US2419367A - Control system for hydraulic hoists - Google Patents

Description

April 22, 1 947 H. RANDOLPH ETAL 2,419,367

CONTROL SYSTEM FOR HYDRAULIC HOIST Filed May, 4, 1940 5 Sheets-Sheet '1 INYENTORSI GAROLD AKANE HARRlSON RANDOEPH 922g; 'ATTORNEY.

3 a wm April 22, 1947. H. RANDOLPH ET AL 2,419,367

CONTROL SYSTEM FOR HYDRAULIS] HOIST Filed Ma 4, 1940 5 Sheets-Sheet 2 1 April 22, 1947 I H. RANDOLPH ETAL 2,419,367

CONTROL SYSTEM FOR HYDRAULIC HOIST Filed May 4, 1940 1 3 Sheets-Sheet 3 A X 192 w //%7 1651 36M [67 26; 165 6 65 36cc j' Z INVENTOR 405 01.17 II. lflm I64 365/ 26 362 BY m msm zrnunoLpu Patented Apr. 22, 1947 CONTROL SYSTEM FOR HYDRAULIC HOISTS Harrison Randolph and Garold A. Kane, Minneapolis, Minn, assignors Company, Minneapolis,

Minnesota to The Northern Pump Minn., a corporation of Application May 4, 1940, Serial No. 333,366

32 Claims.

This invention relates to a control system for hoists and particularly to a hydraulic control system for hoists, While the control system might be applicable to various types of hoists, it is illustrated as applied to hoists of the endless conveyer type. One of the specific hoists illustrated with the control is of said endless type having carriers at opposite sides, One carrier is at the top of one side or at the upper flight level, while the other carrier is at the bottom at the opposite side or at the lower flight level. The hoist is alternately driven in opposite directions so that the carrier at one side is raised while the carrier at the other side is lowered. 1

Another type of hoist illustrated is of the endless conveyer type having a series of carriers thereon adapted to be loaded or unloaded at the same side thereof, said conveyer being adapted to be reversed to raise or lower the material handled.

It is an object of this invention to provide a hydraulic control system for a hoist having two flights movable to upper and lower positions, the control system functioning to initiate a cycle of movement of said hoist under certain conditions of load on the hoist.

It is a further object. of the invention to provide a hydraulic control system for a hoist havingtwo fl ghts, said control system being movable to operative position to initiate a hoisting cycle of movement of said hoist when the lower flight of said hoist is loaded and the top flight is empty.

Another object of the invention is to provide a hydraulic control system for a hoist having upper and lower flights, said system so controlling said hoist that said hoist is inoperative-with both of said flights empty and is inoperative with both flights loaded.

It is a further object of the invention to provide a control system for a hoist having upper and lower flights, said system including means for controlling the movement of said hoist so that a cycle of lowering movement of said hoist may be initiated with the upper flight of said hoist loaded and the lower flight of said hoist empty.

It is another object of the invention to provide a hydraulic control system for a hoist which is constructed to run in either direction under power operation comprising a manual control lever movable to hoist and stop positions, said control system acting to stop said hoist when run ning in either direction if said control lever is moved to stop position.

It is also an object of the invention to provide a hydraulic control system for a hoist having upper and lower flights, control elements actuated from said upper and lower flights, a manually operated control lever movable to hoist and stop positions and a member adapted to be moved to initiate a hoisting cycle of movement of said hoist which is movable only when said control elements are in certain definite positions and said control lever is in hoist position.

- It is still another object of the invention to provide a control system for a hoist having upper and lower flights comprising a hydraulic motor for driving said hoist, a stop means for preventing movement of said hoist, a manually operated control lever movable to hoist and stop positions, a hydraulic control unit including a member movable to power and manual positions, means operated by said hydraulic control unit to release said stop means when said member is in power position and an auxiliary manually operated means for releasing said stop means whe said member is in manual position. I

It is a further object of the invention to provide a control system for a hoist having an upper flight position and a lower flight position, a hydraulic motor connected to said hoist for driving the same, a stop means preventing movement of said hoist, a manually operated member adapted to release said stop means to initiate a cycle of movement of said hoist and a hydraulic control unit controlling hydraulic means for releasing said stop means to initiate a cycle of movement of said hoist.

It is still another object of the invention to provide a control means for a hoist having upper and lower flight positions, a hydraulic motor connected to said hoist for driving the same, a hydraulic control unit including a manually operated member movable to hoist and stop positions, a driven pump, a fluid power line supplied from said pump for operating said hydraulic motor and means for unloading said power line to stop said hoist whenever said manually operated member is movable to stop position;

These and other objects and advantages of the invention will be fully set forth in the following descriptionmade in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

Fig. 1 is a diagrammatic or schematic view partly in vertical section showing one form of control; I

Fig. 2 is a diagrammatic view of the type of hoist to which the control means. in Fig. 1 is applied;

Fig. 3 is a diagrammatic or schematic view partly in vertical section of a slightly different form of control means;

Fig. 4 is a diagrammatic view of the type of hoist with which the control means shown in Fig. 3 is used;

Fig. 5 is a sectional view through a hand drive unit used taken substantially on line 5-5 of Fig. 6;

3 Fig. 6 is a vertical section taken on line 6-6 of Fig.

Fig. 7 is a view inside elevation of a brake ring used;

Fig. 8 is a section taken on line 8-8 of Fig. 1; and

Fig. 9 is a view in side elevation of the parts shown in Fig. 8, some being diagrammatically shown in different positions in dottedlines.

Fig. 10 is a vertical section through'a reversing valve, shown on an enlarged scale;

Referring to the drawings, particularly Figs. -1 and 2, a control system for a hoistsuch as shown in Fig. 2 is illustrated. A hydraulic motor I5 is shown which preferably is of the parallel piston type. Motor l5 has a driven or power output shaft I6 to which is connected a stop cam I1 and a latch cam I8. Shaft it has a beveled gear [9 secured thereto meshing with another gear 20 secured to a shaft 2| journaled' in suitable bearings 22 shown as of the ball bearing type and shaft 2| is connected directly to the hoist driving mechanism. A worm gear 23 is connected to shaft 2i and meshes with a worm wheel gear 24 secured to a timing shaft 25. Timing shaft 25 has'secured thereto a notched timing cam 21, a deceleration cam 28, a snap action valve crank 29 and a deceleration pilot valve cam 3!. It will benoted that shaft I6 is driven at much higher speed than shaft 25. Shaft 25 will make something less than one revolution per cycle, depending, of course, on the ratio of reduction gears 23 and 24 and the number of revolutions of shaft 21 required for a cycle of movement of the hoist.

'Motor I5 is supplied with operating fluid, such as oil, by conduits 34 and 35. These conduits lead to certain ports or passages in a control member casing 36* or valve block assembly. The operating fluid, such as oil, for the motor is supplied by a pump 40. This pump is preferably of the positive displacementconstant discharge type and may be of the gear type. Pump 49 is located in a fluid supply tank 4! and is driven by a constant speed electric motor 42 illustrated as flange mounted vertically on tank 45. Motor 42 also drives in tandem with pump 45 another pump 43 which is of the same type as pump 48. Pump 40 has an inlet 44 and a discharge conduit 45'which leads to a valve block 15 in which is disposed a valve 41 urged to closed position by a compression coiled spring 48 disposed in a chamber in block .46 and having one end engaging valve i! and its other end engaging a closing plug 49 for said chamber. A conduit 59, is connected totank 4i and connects with a pass-age 46a in block 46 shown as connected to apassage 46b with which discharge conduit 45 connects. A pilot valve 41a is disposed in a cylindrical chamber in block 46 acted on at one end by a compression coiled spring 5!. Said chamber has a drain or discharge passage 46h. Member 41a is shown as having spaced lands, one of which is engaged by one end of spring 5| and which controls a vent passage 46d. The other end of said spring 5! engages an apertured closing plug 52 closing one end of the chamber in block 46 which receives member 410,. The other land of valve Ha is disposed in an enlarged chamber in block 46 which is connected by openings with passage 4%. With valve 47a in the position shown,,passa-ge Gdis cut off. Pressure at times can build up below the lower land of member 47a and compress spring 5|. This will permit venting through passage 46d. Valve 41 is arranged to insure a. specific minimum. pressure at all times in conduit 59 when motor 42 and pump 40 are operating. The adjustable spring below valve 41 will be set for a lower pressure than spring 5|. This pressure is determined by the setting of spring 48. Conduit 50 is the conduit for supplying operating fluid under pressure for the parts incontrol casing 36. Also in valve block 46 is a valve 54 acted upon by a compression coiled spring 55 and adapted to control a discharge-passage 46 with which connects one of the power discharge conduits 55 leading to pump 40. Valve 54 is later more fully described. Conduit 56 connects with a port and passage in control casing 38. Another power discharge conduit 51 connects with tank 4| and with a passage in control casing 36. The valve 54 is provided to open at a certain pressure as later described so as to maintain the required pressure in the power line to meet the demands of operation and acceleration of the hoist.

Casing 36 is provided with a plurality of valve passages or cylinders in which are disposed a plurality of valves respectively. A valve 60 is movable in casing 36, the same being shown at the bottom of said casing in Fig. 1, said valve being movable to either of two positions determined by an operating lever El connected thereto and carried on a shaft 62. Conduit 5B connects with a passage 36a leading to the chamber of valve 60. Valve lever BI is movable to one position for power control of the hoist and is shown in this position in Fig. l. Said lever is movable clockwise to another position for manual control of the hoist. Valve-60 is adapted to control venting passages 36b and 360 leading from the chamber thereof. In the power control position in which valve 69 is shown in Fig. 1, it will be seen that con duit 58 is connected through said valve to a passage 3611 leading to the valve chamber of a valve 55 shown as located just above valve 60. Valve is arranged to bemanually operated by a hand control lever 66 carried on a shaft 6! and said lever 65 is movable to either of two positions, one of which is a position to cause the hoist to move through a cycle and is called the hoist position and to another position for stopping movement of the hoist called the. stop position. In Fig. 1 lever 66 is shown in its stop position. Valve 65 controls a venting passage 36?: as well as the passage 35d and another passage 36/ leading from its chamber to the chamber of valve 60. Valve 65 also controls a. passage 36g shown as leading from the upper side thereof and extending to another valve chamber to be later described. Valve 65 also controls another venting passage 35h shown in Fig. 1 as at the top side thereof. Lever 65: has connected thereto a link 68 extendlng upwardly to one arm of a lever 70. It will be seen that lever 10 is of the bell crank type and. has another arm engaging the downwardly extending arm Ha of a bell crank lever 1! having an arm Hb in which is secured a pin projecting into a hori-' zontal slot in a block 72 which has projecting upwardly threfrom a plunger 13 to be referred to later. Apair of valves i5yand 16 are shown disposed in chamber in casing or block 38 above valve 65 and these valves are respectively connected to an upper, flight level control member or lever 11 'and'to a lower. flight level controlling member or lever '18. Lever 11 is adapted to be moved in a counterclockwise direction as shownby a pro- .iectile or shell carried on the hoist as the hoist and shell reach the upper end or upper flight level in the hoist cycle. Lever 11 is carried on a shaft BI and is of the bell crank typehaving its other arm connected to a lever 82 carried on. a

.desired to have the hoist shaft 83 and having oppositely extending arms,

the one opposite that connected to lever 11 being connected to a link 84 which is in turn connected to another bell crank lever 85 carried on a shaft 86 connected in turn to a link 81 which is connected to a control shaft 88 through a lever 89. Shaft 89 is connected through a suitable lever to valve 15 so that said valve is moved'to the left as shown in Fig. 1 when shaft 88 is moved in the clockwise direction, which latter movement occurs when the shell 80 nears the top of the hoist. Lever I8 is operated by 'a projectile 99 when the projectile is placed on the hoist at the lower flight or at the bottom thereof. Lever I8 is shown as of the bell crank type having another arm pressing on a collar 9| surrounding and slidable on a link 92 and having a collar 92a at its lower end. A compression coiled spring 93 surrounds link 92 having its ends respectively engaging collars 9! and 92a and thus acting to urge the left hand end of lever l8 upwardly. When a shell 99 is placed on the lower flight of the hoist the right hand end of lever 18 is moved upwardly and spring 93 is compressed. There is a pot (not shown) in the hoist and the operator puts the shell through the door of the hoist and inserts its pointed end into the said pot. The operator then pushes the shell to vertical position The shell engages the side of lever 18 and cams the same in a counterclockwise direction as indicated in Fig. 1. Link 92 and lever I8 are normally urged to the position shown by spring I98 of valve I6. Spring 93 is provided so that if movement of link 92 is prevented by some extraneous means,

:such as the door latch L, said spring would be compressed and would act to move link 92 as soon 'as said means was removed. A door of the hoist be left open to so position latch L. It is inoperative if said door might is open. Said door would thus have to to be closed before movement of link 92 could occur. As soon as the said shell leaves the lower flight by movement of the hoist, valve spring I99 raises the left hand end of lever I8; Link 92 is connected to a bell crank lever 94 carried on a shaft 95, the other arm of which lever is connected to a link 96, the other end of link 96 being connected to a lever arm 91. Arm 91 is secured to a shaft 98 to which is also secured a lever arm 99. Lever arm 99 has a pin I09 projecting therefrom disposed in a slot in one arm of a bell crank lever IBI, which lever has another arm shown as engaging arm Ila already described. Lever I9! is oscillatable about shaft 88 and has an arm Iilla pivotally connected to valve I6. An arm or lever l92 is secured to'shaft 88 and is adapted to move toward and from and en age depending arm Ila, said lever I92 thus being connected to valve I5. It will be noted that passage 35h in casing 36 communicates with a passage 361 extending at right angles thereto and transversely of block 36, passage 352' having a passage 357' communicating therewith adjacent one side of casing 35 which is controlled by valve 65. Passage 362 communicates at the opposite side of block 36 with a conduit IM which extenm to a hand drive unit I16 for a purpose to be later described. Passage 362' also extends upward in block 36 to adjacent the top thereof as shown in Fig. l and communicates with the chamber of a valve at the top of block 39 to be later described. Valve I5 is engaged by a spring l9? tending to move it to the right as seen in Fig. 1 and said valve controls a passage 96k shown as at the lower side thereof. Valve I5 also controls a passage 36m be moved extending to the chamber of valve I6 and it controls another passage 361: shown as extending to another valve in block 36 to be later described. Valve I6 has a collar 16a at its inner end of smaller diameter than the chamber in which it is disposed, which chamber is open at the side of block 36. It will be understood that block 36 will be contained in an oil-containing casing. Collar 'I'Ea is engaged by a compression coiled spring I08, the other end of which en ages the inner end of said chamber. Valve I6 has an intermediate reduced portion 1% at the inner end of which are a plurality of radially extending slots 16c. Fluid can thus pass from about portion 16b through slots ltc to the chamber containing spring I98 and collar 160. A by-pass creeper valve H9 is shown in block 35 above valve 16, the same being adapted to be adjusted to control the rate of flow of oil through a passage 360 which extends upwardly to the chamber of a decelerator valve to be later described. A valve H2 is disposed in a H217 therethrough into which plunger I3 is adapted to enter at certain times. Extension I I'm also has a slot in the top in which is disposed the lower end of a lever arm I l5 secured to a shaft I I6 journaled in suitable bearings H'I, which shaft extends upward and has secured to its upper end a lever arm I I8 which has its end disposed in a slot intermediate the ends of a pin or plunger H9. Plunger H9 is adapted to cooperate with a snap action valve in the upper end of block 36 to be later described. A lever arm I2! is shown as mounted on a shaft 22 and moving between stops i 23 and as being acted upon at one side by a light spring I24. Lever IZI also has an extension I2Ia movable along the top of extension IIZa over aperture H212. Stops I23 are provided so that lever l2l will not be moved sufficiently to place excessive drag on pin I3 or to move valve H2 so that its inner end will engage plug H4. Lever i2% is an auxiliary hand lever adapted to initiate a cycle, or in other words to start the hoist in a cycle of movement when it is under manual control. Extension 2a has connected to its outer end a link E25, the other end of which is pivotally connected to a starting latch I29. Starting latch 526 has a tooth or dog at one end adapted to ride upon the latch cam I8 and to engage against a shoulder on said cam. The stop cam l! is engaged by a stop latch or dog I28 oscillatable about the axis of shaft I29 on which it is carried. Stop latch I29 has a tooth or dog at one end adapted to ride upon cam I! and to engage the shoulder of a projection Ila thereon. Latch I28 also has a toothor dog adapted to ride upon the periphery ofcam 2'! and to engage a shoulder 21a on said cam. Latch 728 is moved toward cam 2'! by a plunger E36 carried in a casing I3I and urged toward latch 929 by a compression coiled spring L92. Another plunger I33 in casing it! engages the side of arm '5 l a tending to move it in a clockbrake ring I92 is disposed in the casing of the hand drive unit having radially disposed teeth I92a-on one face thereof adapted to engage similar teeth I93a on a member I93. The teeth IBM and H331: are normally held in engagement by a compression coil spring I94 engaging members I99 and I92. Members I99 and I92 are .connected by interengaging radial teeth I92d and I99b. -The shaft I9I is connected to'a member I95 whichcarries a pair of radially and oppositely extended-rollers I96 having trunnions which are disposed in member I95 and pinned therein by pins two.oppositely disposed pins I98 which are disposedin elongated slots I92b, and member I92 has in its face oppositely disposed V-shaped grooves I920 in which rollers I96 are normally disposed. The described structure is such that upon-rotation of shaft I9I through an arc sufflcient to take up the lost motion of pins I98 in slots I921) the rolls I96 will move out of the slots or grooves I920 and will separate teeth I92a, I93a, member I92 thus moving toward member I99.

The required operation of the hoist is as follo'wsz I With both flights of the hoist loaded or with articles on both carriers 299 and 29I the hoist is inoperable. With both ofsaid flights or carriers empty the hoist is inoperable. With the lower flight or carrier loaded and the topflight or carrier empty and manual control lever in hoist position the hoist operates to move through one cycle.

That is, the lower flight or carrier 299 will move'to its upper position and the upper flight or carrier 29I will move to its lower position. In other words, with 299 as shown in Fig. 2 --loaded and 29I empty, when the proper combination of parts is secured the hoist will operate to move 299 to the upper flight, indicated in Fig. 2, andi'zfll will move to the lower level as indicated in Fig. 2. This movement comprises a, cycle. As before stated the movement of the endless chain or endless member of the hoist is reversed for each successive cycle. With thehoist running in either direction (under power operation) throwing the manual control lever 66 to stop position stops the hoist.

Reviewing the diflerentvalves described it may bestated that valve 41 functions to insure a speciflc minimum pressure in conduit 59 which supplies'the fluid or oil under pressure to control casing 36 and parts therein. The relief valve 54 opens at a specific pressure determined by the setting of pilot spring 5|. This pressure is set according to the acceleration demands of the h'oistp Valve 69 is manually operated through lever 6I. When placed in power position pressure is admitted to the control system through -conduittil, passage 39a and passage 36d. Valve 69-is shown in power position in Fig- 1. When this valve is placed in manual position it moves to the right as shown in Fig. 1 and its centralland cuts off passage 39a, thus shutting oil fluid under pressure from the control casing 36 and parts therein. Pressure in the control system'is relieved and spring IBI acts to engage clutch I86 and connect hand drive unit II6 with output shaft 21'. If valve .99 is moved to its manual control position While the hoist is running this will cause no damage as the hoist will merely be braked through the friction clutch I86. Another function of valve 69 is to relieve the pressure on topof valve I52 or event said valve. This is done throughpassa'ge' 36g which leads to the chamber I91. Member I95 also has secured therein of valve I52 and then downward as shown at the left hand side of block 36 to valve 65. Passage 36 leads from valve 65 through the chamber of valve 69 to a vent passage 36c.

Valve 65 has two positions and is manually operated by the hand control lever 66. Said lever as above stated is movable to one position called the hoist position and another position called the.stop.position. With said lever 96 in stop position the hoist is inoperable regardless of the positions of'the other parts or ,valves. As above stated throwing control lever 99 to stop position stops the hoist immediately and unloads the main flow if the decelerator valve I46 is in closed position. This is done by relieving the pressure on valve 52 through the passages just above traced. Valve. E52 opens and the fluid passes from power pressure line 55 through passage 39a past valve I52 now open and around decelerator valve I46 sure conduit 59 then passage 36a, valve 69, passage 35d, valve 65, passage 39h, valve I5 (lower flight loaded), passage 66m, valve l5 (upper flight empty) and passage 3911 to valve I I2.

Valve II.2.is' normally under pressure of spring H3 and serves two functions. (When operating conditions are correct it acts to initiate'aghoist cycle by. being moved to the left as shown in Fig.

1 to swing start latch I29 out ofengagement with latch cam I8. Valve II2 also acts to unload or relieve the main line whenever start latch I26 is engaged with cam IIB. This unloadingor relief can be traced from the chamber "of valve I52 through the vertical portion of passage 369 through its, horizontal portion to the intermediate part of valve H2 and then through passage 36p. The stop cam I1 and the latch cam I8 are rigidlysplined to shaft I6. 7

Valve I49 has two positions, and as shown, is actuated by a two-level decelerate valve pilot cam 3|. Positioned in combination with valve II9 it admits pressure to .or relieves pressure from the decelerating valve plunger I46 according to the operation of the hoist and the requirements of the control system. The admission of pressure to valve I46 may be traced from passage 361 throughpassage 3911. through valve65 through passage 36d and through valve 69 tothe pressure line. 59.. From passage 961 the pressure is transmitted through passage 36M through passage 36r through valve I49 and through passage 36g to the right hand end of valve I49. With valve I49 in its other position, that is, moved ,to the left from the position shown in Fig. 1, the pressure would be relieved from valve I46 through passage 39g, passage 36t, one end of valve I64, passage 39cc, through valve I19 and out through passage 36ee.-

Valve I64 as stated is a reversing valve which directs flow to the hydraulic motor I5 in onedirection or another according to the direction of rotation and the movement of the hoist required. It will be seen that when said valve is moved to the left the discharge pressure line 59 from pump- 49 will be connected to conduit 34 and whensaid valve is moved to the right said pressure line 56 will beconnected with conduit 35. Thelands on valve I 64 are undercutto permit bypassing of the .1 1 fluid with the valve positioned in'its centralposition, as shown in Fig. 1. This isv the normalposition with the hoist inoperable and for manual operation of the hoist.

As above explained the valve M6 is a decelera ing valve and cuts ofi the main line flow from the hydraulic motor 15 to the supply tank 4: at a rate determined by the contour of the decelerating cam 28. This cutting off as will be plainly seen is done between passage 35g and 36w and the passage communicating with conduit 57. Any desired or predetermined minimum terminal velocity of the hoist may be obtained by adjustment of the bypass creeper valve H0.

V alve H is a snap action detent valve and has two positions. This valve is put under spring pressure or cocked at the end of each operating cycle by the valve crank 29 placing spring I'H under pressure to move the valve in one directionor the other. When so cocked plunger H9 is engaged in one of the recesses or sockets llila. At the completion of a cycle stop latch. [2'8 drops into its'notch on the timing cam 21. This allows movement of start latch J25 andpermits spring H3 to move valve H2 to the right as shown in Fig. 1. This through lever arm H5 rotates shaft I Hi and through lever arm 5 l8 lowers plunger i ii so that spring Ill is free to move valve no. The position of valve Hi3 determines whether reversing valve Hie-will be in one position orthe other.

This is done through-pressure being placed in either passage 36110. or passage 3500 from pressure-passage 351'.

The purpose of valve ilfi is to control movement of fluid to one side or the other of the reversing valvelfid. The reversing valve must be moved to the proper position either to have the hoist lift or to have it lower. The valve H0 is 'cockedjand'held by the detent I 16 until the proper time to start the cycle for the reversed movement'of the hoist.

- -Thes'tart and stop latches .l26 and I28 are oscilla'table on shaft I29. Latch 1.26 may be disengaged only by motion of the extension 2a of valve I I2. This motion may be initiated by manual operation of auxiliary hand lever l2! or by power through operation of valve I I2. Themain function of the start latch I25 is to prevent initiation of another or reverse cycle before the proper combination of valves and other interlocked portions has been obtained. There is sufficient lost motion between the arm of latch I28 which engages cam 21 andthe sides of the shoulders on notches 27a. to allow the camming ,surface on cam I! at its highportion to disengage latch I23 from said notches or shoulders on cam 21. The lug I28a-onlatch I28 engages the pin' I27 on latch I26 and this prevents the tendency 'of latch I26 to swing under pressure of spring I I3 and to thus engage the notches in the high speed latch cam it before the end of a cycle has been reached. Valve 54 can be called, a pilot-operated relief valve. As shown in Fig. 1 this valve is in closed position, shutting oiT the passage 46] leading downward therefrom into the tank 4|.

it does not obstruct'passage 460 since liquid can pass around it since it .is of smaller diameter thanits chamber. It will be noted that the upper land of valve 4.1a is closing vent passage 46d through passages 46h so that pressure will ;be built up in the chamber of valve 410., which pressure is exerted ontop of valve .54 through passage 469. 'When this pressure exceeds the pressure ofspring-tl valve-41a will be-moved upward by pressure on its'lower land and theupperland thereof will uncover the port of passage 46d so that the pressure will be relieved. Thelower landron valve 41a moves upward andshuts off admission of .pressure to passage 46g so that thereis no pressure on top of valve 54,,passage 35g being now connected with passage 4612. Under these conditions valve 54 can liftand'the main line will be vented or unloaded throughpassage 46]. Spring 55 is provided tostartornormally urge valve .54 toward its seat. The vdescribed parts are provided to take care :of excess pressure which might develop in the line or system. Suchpressure actually develops at the beginning of a hoisting cycle during acceleration of the hoist. In one embodiment of the invention in actual practice the pressure ,at-which spring 5| will compress has been 700 pounds.

The purpose of the device is to properly control the hoist and the hoist has been used to elevate a shell from the magazine of the warship. to the gun. Hydraulic control is .used as there is no danger of sparking as with electric -devices,-and a very accurate control can be secured. The hoist. must move very-rapidly. It must be deaderated so that'there is absolutely no tendency for the shell to move away from the hoist at the end of the lift and sothat the hoist-comes to rest very gently. The hoist must be capable ofzb'eing iinstantly reversedor stopped. All of these movements require thevarious valvespplungersand levers described. Each'of these is necessary. 'As disclosed,.the hoist is directly connected to the output shaft 2|. This connection :isnot-shown but the proper mechanical means will "be-used. The hoist can either be operated manually by putting a crank or other moving element onshaft l'9l, or it can be operated-by power which of course, is the desired way of operatingit. .If lever 6! ismoved 'topower position theparts will be set for fpower operation and if lever 6| is moved to manual position'the parts will be set for manual operation. Lever Bfi canbem'cved to stop position to stop the hoist at any time or it can be moved to hoist position and set the parts for the hoist to operate. Cam shaft 25 is driven at slow speed from the operating shaft 2| and moves through a comparatively small dis-.- tance. Cams 21, '31, 28 and arms 29 are rotated by shaft .25. Shafts l6 and 2l will'make quite'a number of revolutions during the raising or lowering of the'hoist. For either power or manual the lower position or lowertflight level to the upper position or upper fiight level and .vice versa to carry the shells.

Bearing in mind-the above facts the operation of'the hoist is as follows: I

With the parts in the position shown in Fig. 1,

the lever 6| is shown in its power position and it will beseen'that fluid under pressure is delivered from conduit 5ll through valve 60 to passage 36d. 'As above stated however; the hoist is not too'perate until the lower flight is loaded. .With the parts-in the position showninxFig-I,.the.1o.w-

13 er flight is empty and lever Illl through the described linkage to lever 18, isheld in position against lever arm lIa. Lever II therefore, cannot be moved and valve H2 or its extension IIZa cannot be moved to release latch I26 which would permit shaft I6 to rotate. If now the lower flight be loaded, lever l8 will be moved upward as described and through the described linkage lever IIlI will be moved away from the depending lever arm 'IIa. However, arm Ila is still engaged by lever It. This is because hand control lever 66 is in fstop position. This lever must be moved to hoist position before the hoist can operate. This lever now being.

moved to hoist position, thus being moved in counter-clockwise direction, link 68 will be actuated and lever 16 will swing away from arm 'IIa. The'parts are now in position to start a cycle. It will be seen therefore, that in orderto start a cycle, the levers Ill, IDI and I02 must be in proper position. It will be seen that with said levers moved to the proper or operative position they are moved away from arm 'I la so that springactuated plunger I33 will swing arm Ha and plunger or pin I3 will be moved into and through.

aperture H21) in extension II2a by movement of member I2 which is moved by lever II. It will be seen that if lever ll had been in manual position the auxiliary hand lever I2I could now be movedin a clockwise direction and its extension I2Ia would be in position and would engage pin [3 projecting through aperture I I2!) in extension IIZa and thus move extension H211. The start.

latch I216 would thus be disengaged from latch cam I8 so that a cycle could be-started by manual operation. With any one of the levers I6, II or I02 in non-hoist or non-operative position it is impossible to initiate a cycle manually as lever 'II cannot be moved to project pin I3 through extension I I2a and movement of auxiliary hand lever I2I would produce no result.

It may be stated that under normal operation as soon as the projectile or shell 96 being hoisted leaves the lower flight level, lever Ifll by acting on lever II will cause plunger or pin 13 to be withdrawn from valve extension II2a. This will permit spring I I3 to move extension I I2a to bring latch I 26 in position to again engage cam I8- Thus regardless of subsequent movement of the auxiliary lever I2I latch I26 will be in position to engage cam I8 at the completion of the cycle..

If the lever 66 has now been moved to hoist position thus moving valve 65 to the left from its position in Fig. l and with lever 6I in power position with the upper flight lever 11 in the position shown and the lower flight lever 18 in loaded position as above described, conditions are proper for a cycle to be initiated by power operation. The combined positions of valves 66, 65, I and 16 now admit pressure to the chamber of valve I I2. This is done by pressure fluid from conduit 50 passing through passage 36a around valve 60 through passage 3601, around valve 65 now in hoist position, through passage 36h, to valve 16 now in loaded position, through passage 36m, around valve "I5, through passage 36m. to

valve I I2. This pressure of fluid on valve I I2 will move the valve to the left as shown in Fig. 1 and start latch I26 will be moved out of engagement with cam I8. It will be noted that start latch I26 is first moved. Pin I2! is carried on latch I26 and when latch I26 is thus moved to permit the initiation of a cycle pin l2! moves away from lug I28a so that-movement of latch I28 can take place.

Latch I28 of course, does not move until thehoist connected I starts to operate. latch I28 is actuated upon by its cam 21, lug I28a will again engage pin I21 and raise latch I26 so that it will be sure to be kept out of the path of cam I8 during the cycle. Cam 2! acts on latch I28 to hold it out of engagement with cam I'I during the proper period.

When valve II2 thus moves to the left it cuts off the venting passage from valve I52 allowing pressure to build up above or at the left of said valve. Valve I52 is thus moved to closed position. When valve 65 is moved to hoist position pressure is admitted to conduit I04 through conduit 50 around valve 60 through passage 36d, around valve 65, through passage 36h and to passage 362' and conduit I64. This admits pressure to the chamber I88 in the hand driven unit and the friction clutch I86 is released. This clutch should be released so that it will not retard or interfere with the power operation. Snap action Valve I10 admits pressure to the left hand end of reversing valve I64. from passage 3m around valve I70 and through passage tfidd to the chamber of valve I64. Valve I64 is thus moved to its right hand position and fluid'under pressure is now directed from conduit 56 through passage 3% and passage 36a and passage 36b?) through conduit 35 to motor I5 and the fluid returns through pipe 34, passage 36aa and through reversing valve I64 to passages 36y and 36w around valve I46 to conduit 5] and back free flow of the fluid. The motor I5 is thus operated and the hoist lifts. When valve II2 was moved to the left either by power or by the auxiliary lever I2I, plunger M9 was raised and it engaged in one of the recesses IIIIa. Valve I10 is thus held in stationary position. As stated, the purpose of valve I16 is to control the movement of fluid to one side or the other of the reversing valve I64. Valve I64 determines whether the hoist lifts or lowers. ed and held by the detent I I9 so that it will only act at the proper time. As soon as valve 16 moved to its left hand position the pressure on valve H2 was unloaded or vented and this action took place through passage 361i to and around valve 15, then through passage 36m to valve I6 through slots 16c and around valve end 16a to tank. Valve 15 operates to connect passage 3611. to passage 367a and exhaust and to cut off passage 36m so that valve I I 2 is vented and even though valve 16 be operated when a shell is loaded at the lower flight to move lever 18, valve II2 will not be moved until the shell is unloaded at the upper flight. Lever 'II operates to move lever I02 to prevent lever II from operating until lever 11 is I released on unloading. As the rotation of the output-shaft 2I which drives the hoist progresses,

through passage 3600, around valve Ill] and to tank through the'right hand end of passage 36ee.

This venting in mid cycle has no effect on the;

It may be stated that when- This pressure is applied Valve I'I'il is cooked or load- 15 operation. of the hoist, that is, on the flow from the hydraulic motor as the high side of the deceleration cam 29 is under the plunger roller at the-moment of release. It howeven prepares the deceleration valve for functioning under the action of its compression spring I41 at the end of the cycle. Near the end-of the cycle, crank-or lever 29 engages collar il'2a to compress spring I'H, valve l'iIl being held by detent plunger H9, and when the high point of cam 21 passeslatch I28, I28 will be operated by I39 to move to the low point of cam 27 so that I290, may move up from pin 12'! so that spring H3 moves extension I IZa to the right, thereby releasing plunger H9 from its opening I'Hia so that valve I19 will be shifted at this time. Also when valve I I2 moves -to the right the chamber behind valve I52 is vented through passages 36g and 36p so that valve I52 will open to relievepressure in line 55 and thus act to stop operation of motor I5. When plunger II9 releases valve I79, spring I'H will move valve I 19 to the left so that pressure is admitted to passage 3600 to move valve I94 to the left at this time. Also as cam 3I has moved valve I49 to the left at this time to connect passage 39f to passage 35g, pressure will be admitted to move valve 49 to the left so that valve I64 will be ready to reverse the flow in motor lines 34 and 35 upon closure of valve I52. As the cycle continues spring I 4! acts to move deceleration valve I46 to the right and the slots I46a gradually throttle the return of oil orfluid to tank so that the desired deceleration takes place. At the completion of the cycle the start latch I26 which is already described, has been moved to position to engage its .oam, again engages with cam I8 and latch J28 engages with cam I7 and the cycle of liftiscompleted. Another cycle cannot be initiated until the levers 79, I9! and I 92 are in proper position and lever 68 is either moved to hoist position or auxiliary lever i2! is again operated. If lever 65 is kept in hoist position the projectile removed at the top flight level, and another projectile placed on the lower flight, the hoist will continue to operate.

During a cycle therefore, as stated, 2% as shown in Fig. 2 moves from the lower flight level to the upper flight level and 29! moves from the upper flight level to the lower flight level, as indicated in said figure. As stated, with 299 at the lower flight loaded and lever 6! in power position, and lever 95 in hoist position, and 29I empty, a cycle will be initiated. The loading of the shell at the lower flight moves lever 18, as stated, to bring about one of the requirements for the initiation of a cycle. 299 then moves upwardly and lever l? is operated as the shell nears the upper flight. Lever 'l? is so held until the shell is unloaded at the upper flight. Reverse operation, therefore, cannot begin until 296 is unloaded. After 29% is unloaded and 29I is loaded (being now at the lower position) to move valve H2 to the left, to now latch plunger H9 into the other recess Him, to hold valve Ill? in its new position, the operationin the reverse direction will begin, i. e., 29! will rise and 299 will lower. When 29I rises, it operates valve l5 through lever 11 as described, so that pressure will be relieved from valve I I2 and lever arm 29 willoperatevalve I79 to shift the same after the highpoint of the cam 21 passes latch 28 so that H2 can move to the right torelease plunger 5 I9 to permit such movement. Then, as already described, 2-9I must be unloaded to release valve 15 before loading of 209 at the lower level will cause release of latches sion coil spring 231.

. ment of spring 23?.

I23--and I26, pressure being admitted to passage 36?; to move valve-t 2 to the lefton operation of levers l8 and ll. The main or pressure line being vented at the-end of the cycle, the hoist will stop when the stop'latch I28 engages stop cam I 1. It will'remain stopped until conditions are again present for the initiation of a cycle. 'As stated, if lever 8| remains in power position and lever 66 remains in hoist position, another cycle Will start immediately if the lower flight is loaded and the upper flight is empty.

Referring to Figs. 3 and 4 a control system having many features similar to that illustrated in Fig. 1 is shown. The'system comprises a hydraulic motor 2l5 having a driving shaft 2I6. Shaft 256 has secured thereto a gear 2I'l meshing with a gear 2E9 which is secured toand drives a shaft-2I9 which may be called the output shaft and which is directly connected to the hoist.-

ShaftZ I9'also has connected thereto a bevel gear 229 meshing with a beveled pinion 22I secured to a shaft 222 to which is secured a gear 223 in turn meshing with a gear N8 of the hand drive unit I'll-3 illustrated in Fig. 5. Shaft 2I9 also has secured thereto a gear 224 meshing with a gear 229 secured to and driving a timing shaft 226. Timing shaft 226 has secured thereto a hoist stop cam 221, a lower stop cam 228, a snap action valve cam 229, a decelerating cam 230 and a flight level cam 23 I. Fluid is supplied to-the motor 2I5 from a pump 43:disposed in the supply tank M and driven from electric motor 42 in tandem with pump 49. A supply conduit 234 extends from pump 43 to a valve block 235. Conduit 234 connects with a passage 235a in block 235 which is governed by a valve 235 acted on by compres- Valve 236 acts to maintain a certain minimum pressure-in a passage 23% and a conduit 249, depending upon the adjust- Another valve 24I is acted upon by a spring 242. Valve MI is pilot operated and controls a passage 2350. The pressure at which this valve opens is determined by the settingof a pilot spring238 of a valve 239 adapted to control a vent passage 233d. Valves 236, MI and 239 and their cooperating passages are identical with valves 4?, 54 and 46a and their cooperating passages in Fig. 1 and need not be again described. A return conduit 244 is shown as connected to tank 4!. Timing shaft 226 makes one revolution per cycle.

A valve block 248 is shown and conduit 244 communicates with a passage 249a therein leadingto the cylindrical valve chamber of valve 249 which is a decelerator valve, the same being shown as acted upon by compression coil spring 259, one end of which engages the end of said valve and the other end of which engages the end of said valve chamber. A vent passage 24Gb extends from one end of said valve chamber to theside-of block 248 and thus to a tank or casing in which block 248 will be disposed; Valve 249 has an operating head at its left hand end and g is shown as having a plurality of circumferentially spaced arcuate passages or slots 249a at one end. Valve 249 also-has an operating plunger shown at its right hand end and a passage 248a communicates with the valve chamber at the right of said operating plunger, said passage connecting with aconduit 29! leading to another valve control assembly comprising a casing or valve block 252. Valve 249 has a'rod projecting therefrom arranged to engage a cam roller arm 24'! having a cam roller 248 journaled therein adapted to be engaged by cam 230. Arm 241 is oscillatably mounted on a shaft 24111. A passage 248d extends downward from the chamber of valve 249, this being one of the passages of the power line and is the passage adapted to be cut oil by movement of valve 249. Passage 248d extends through the valve chamber of a valve 253. Said valve has a valve plunger acted upon by a compression coil spring 254. Pressure of spring 254 can be adjusted by plug 255 engaged by one end of said spring and threaded into block 246. A passage 248a extends from one end of the valve chamber of valve 253 to the valve chamber of a reversing valve 256. A short passage 248 extends from passage 248d to adjacent one end of the valve chamber of valve 253. The valve 253 is provided to impose a restriction in the return flow of fluid from the hydraulic motor during a lowering cycle. It is provided to prevent undue acceleration of the hoist if the direction is changed in mid-cycle from hoisting to lowering. Valve 253 also functions to impose a restriction on the flow of fluid in hydraulic motor 2E5 when the hoist is being operated manually in a lowering cycle. This restriction imposes a sufficient back torque on output shaft 2|6 to insure quiet operation of the hand drive unit I16 when performing a lowering cycle with a loaded hoist. Passage 246d also extends to the chamber of reversing valve 256. A ball check valve 258 is provided in block 248 shown as having its chamber connected to passage 248e. Said valve is of the usual ball and spring type. Passage 248d communicates with an annular port about valve 258 and one or more holes 258a communicate with this port. Valve 256 as stated, is a reversing valve having lands symmetrically disposed about the center thereof and being acted upon at each end by compression coil springs 259. It controls passages 243e and 248d as well as passages 2489 and 24872. which lead to the conduits 266 and 26! connected to hydraulic motor 2l5. It will be obvious that as valve 256 is moved to one side or the other that it will reverse the direction of flow through conduits 266 and 26l to the motor 2i5. A conduit 262 extends from one end of the valve chamber of valve 256 to the valve block 252. Another conduit 263 extends from the opposite end of the valve chamber 256 to the valve block 252. It will be seen that a passage 2482' in block 248 communicates with conduit 243 leading from valve block 235 in tank 4| and is connected to a passage 2487' shown as extending downwardly centrally from the valve chamber of reversing valve 256 to the closing or sealing end of a valve 264 shown as acted upon by a compression coil spring 265. Said end of the chamber of valve 254 is also connected by a passage 24870 to passage 248a adjacent the top of block 248. Valve 264 is so constructed that it will open when pressure on top of it or at the right of it as shown in Fig. 1 is relieved. Valve 264 is similar to valve I52 shown in Fig. 1. It will be noted that the said valves have a central opening adjacent the seatthereof which communicates with a passage having lateral openings adjacent the seat. When said valve is moved to closed position by its spring oil from the pressure line can pass through said lateral openings and through said central opening and build up a pressure above the valve which will tend to hold it closed. When the chamber above the valve, however, is vented through conduit 261, around valve 326 and passage 252s, then this pressure cannot build up and said valve will open by the pressure around its lower or seating end.

A conduit 261 leads from the top of valve 264 and its valve chamber to valve block 252.

Valve block 252 has a valve chamber therein at its bottom in which is disposed a valve 210. Valve 210 is moved by a manually operated lever 21! movable to two positions, one of which is for power operation of the hoist and the other of which. is for manual operation of the hoist. These positions are indicated by M and P adjacent lever 21!. Valve 216 in Fig. 3 is shown in'position of power operation. Valve 210 controls the supply of fluid under pressure to the control assembly in block 252 and controls a passage 252a communicating with conduit 240 above described and through which fluid under pressure is supplied to the control assembly and block 252. Valve 216 controls venting ports 252p and 2520. Said valve at its upper side also controls passages 25201 and 252e which lead to the valve chamber of a valve 212. Valve 212 is moved by a manually operated lever 213 which is movable to three positions, namely: a hoist position, a stop position, and a lower position which is the position for lowering the hoist. These positions are indicated in Fig. 3 by the letters H, S and L respectively. It will be noted that lever 213 is shown in its stop position. Valve 212 controls a vent passage 2521 having two branches communicating with its valve chamber and said valve is shown as controlling passages 252g and 252h leading from the upper side thereof. It will be noted that with lever 213 in the stop position shown that the upper end of passage 252e is shut oil so that no fluid under pressure from conduit 246 can pass above valve 212. It will be noted .that passage 252e has a branch shown as leading to the right between valves 216 and 212, which passage extend upwardly to adjacent the top of block 252 and communicates with a valve chamber at the top of block 252 to be later described. It will be seen that with valve 210 in its power position as shown fluid under pressure is supplied to passage 252e. Lever 213 has one arm thereof connected to a link 214, the upper end of which is pivotally connected to a lever 215 having a vertically extending portion. Another valve 216 is disposed in a chamber above valve 212 in block 252. This valve has connected thereto a lever 211 which is controlled from the lower flight of the hoist. Said lever has three positions, one of which it occupies, when the lower flight of the hoist is empty, another of which it occupies when the hoist is not operated or in neutral, and theother of which it occupies when the lower flight is loaded. These positions are indicated in Fig. 3 by the letters E, N and L. It will be seen that the chamber of valve 216 has an enlarged portion at it right hand end in which is disposed a compression coil spring 218 acting on valve 216 tending to move it to the position shown, which is the position with the lower flight of the hoist empty. It will be seen that valve 216 controls passages 252k and 252g at its lower side. Said valve also controls the passage 252i shown at the upper side thereof as well as another passage 2527' at its upper ide and a passage 252k at its upper side. It will be seen that a portion of the valve shown as adjacent the enlarged part of the chamber has circumferentially disposed slots 216a therein through which the fluid may pas from the valve chamber into the passage 252k. Lever 211 is secured to a shaft 219 about I the axis of which lever 215 oscillates and which shaft has secured thereto a lever 280 shown as disposed adjacent lever 215 already described and 19 having a vertically extending portion adjacent the similar portion of lever 2'55. Block 252 also has therein a valve chamber in which is received the valve 282 shown at some distance above the valve 212 and this valve has connected thereto a lever 283 which is operated from the upper flight of the hoist, said lever having three positions, namely: one position when the upper flight is empty, another position when the upper flight is loaded and another position when the hoist is inoperable, or in neutral. The loaded, neutral and empty positions are indicated in Fig, 3 by the letters L, N and E. It will be seen that lever 283 has an arm connected to a link 234 which is shown as extending downwardly and pivotally connected at its lower end to a lever 292. Lever 290 is shown of the bell crank type similar to lever 275 and has an upstanding portion disposed adjacent the upstanding portions of levers 275 and 280. The levers 275, 239 and 293 are adapted to have said upstanding portions engage the depending end of a lever 29! pivoted on a shaft 2920!. having another end pivotally connected to the lower end of a vertically movable rod 292 guided in a bracket 2% and having a pin projecting laterally from its upper end disposed in the slot of a plunger head 294a of a plunger 294 for a purpose to be later described. Said vertically extending portions of lever 275, 2th and 290 are also adapted to engage with the depending end of a lever 296 also oscillatable about shaft 292a and having an arm pivotally connected to the lower end of a rod 291 also guided in bracket 233 and having a pin projecting laterally from its upper end disposed in a slot in a plunger head 288a of a plunger 238 "to be later described. It will be seen that valve 232 like valve 213 thus has three positions. Valve 282 controls at its lower side a passage 25272 which extends downward to the valve chamber of valve 273. Valve 282 also controls on its lower side a passage 252k already described which extends down to valve 225 adjacent the right hand end of the latter. Valve 282 also controls at its upper side a passage 252m which extends upward to another valve chamher in block 252 to be later described. Passage 252m has a branch 2520 communicatin with the chamber of valve 222 some distance from passage 25211. The chamber of valve 282 at its right hand end is enlarged and said valve has a portion thereof surrounded by a coil compression spring 293 one end of which bears against the inner end of said enlarged portion and the other end of which bears against a flange or collar on valve 282 so that said spring tends to .rnove said valve to the right or to its position shown. A plunger 32!) is disposed in a chamber of a casing 30! and is pressed upon at its inner end by a compression coil spring 322. Spring 3E2 tends to press plunger 390 against the lower end of lever 29L Another plunger 303 is disposed in a chamber in a casing 32% and is acted upon by a compression coil spring 335 tending to move it into engagement with the lower end of lever 29!).

A valve 322 is disposed in a valve chamber above valve 213 in block 252, said valve having projections at its ends adapted to engage projections on closing plugs 30? and 338 in the ends of its valve chamber. Valve 335 is adapted to cooperate with passages 252i and 2527' already described and with a passage 252p shown as disposed therea'b'ove and which communicates with a conduit 339 shown as extending to portion l8! of the hand power unit and which will correspond to conduit I04 illustrated in Fig. 1. Valve 306 is a shuttle valve and is provided to ensure that fluid under pressure will be admitted to chamber I88 of hand drive unit I76 regardless of the direction of flow of the fluid in the control system.

Above valve 326 block 252 has a valve chamber therein in which is disposed a valve 3E2. Valve 3E2 has a stem projected from block 252 having thereon a block 3l2a having an aperture therethrough through which pin or plunger 294 is adapted to be moved by rod 292 actuated by lever 29!. Valve 3l2 is adapted to have pressure placed on its left hand end through a passage 252q and said valve has its right hand end disposed in a rather large chamber in block 252, which right hand and is acted upon by compression coil spring 1H3 which tends to move valve 312 to the left. The rod projecting from valve 352 is pivotally connected at its outer end to a stop latch 3M adapted to cooperate with and engage a step or shoulder on hoist stop cam 221. Latch 3M is shown as swingable about a shaft 3-l5. Another valve 316 is disposed in a chamber in block 252 above valve 3H2, valve 3L6 also having a rod projecting from said block, the same carrying a rectangular block 3l6a which has a vertical aperture therethrough through which plunger 298 is adapted to be moved at certain times. An auxiliary hand control lever 3| 1 is provided, the same being shown as oscillatable about a shaft 318 and having a downwardly extending arm provided with a central open-ended slot into which projects a pin 319 secured to a member or dog 320 which has arms or pins projecting therefrom disposed respectively over and movable over the blocks 3l2a and 3l6d. A tensile coil spring 321 is shown as connected to a third arm of lever 3! l and extending to and connected to casing portion 322. The rod projecting from valve 3E5 is pivotally connected to a stop latch 3H cooperating with lower stop cam 228. It will be seen that if lever 3!"! is swung in a counter-clockwise direction that it will move dog 320 to the right as shown in Fig. 3. If one of the plungers 294 and 238 is projected above blocks MM and 3l6a it will be engaged by the respective portion or pin projecting from dog 323 and will be moved to the right, thus moving with it the rod of either valve M2 or ens. Valve 3l6 is adapted to have fluid pressure applied thereto at its left hand end through a passage 2521, which passage extends upwardly to another valve to be later described. Valve 316 is engaged at its right hand end by a compression coil spring 324 which tends to move it to the left as shown in Fig. 3, or in a direction to engage stop- 3 with its cam. Valves M2 and M6 are coupled to another valve 326 by a coupling member 326a which is also acted upon by a compression coil spring 32'! tending to move it to the left as seen in Fig. 3. Valve 326 controls a vent passage 252s and also controls a passage 252i which communicates with the conduit 26'! and has a portion extending downwardly and connecting with passage 252d just above valve m. Valve 326 is an unloading valve pilot provided to unload the main line through valve 264 at the completion of a cycle of movement of said hoist in either direction when both stop latches 3H and 3M engage. Said valve controls the motion of unloading valve 264 by cutting oil or venting ,a line from its chamber.

.Another valve 335 is provided in valve block 252, the same having .an extension or red projecting from said block and provided with a cam roller 33l adaptedto engage cam 229. Valve 330 is moved by the cam against the pressure of a compresison coil spring 332a engaging the same and tending to move the same to the left as shown in Fig. 3 or to move roller 331 toward cam 229. Valve 330 has a recess 330a therein adapted to receive a detent plunger 333 which is moved toward said valve by compression coil spring 332. Plunger 333 is arranged to be moved away from valve 330 by fluid pressure applied thereto through a passage 252a. Passage 2521.; connects with passage 2521" already described. Valve 33!! also controls a passage 252v shown as leading from the lower side thereof down to and connecting with passage 252h. Valve 330 also controls a passage 252w shown as leading from the top of its chamber to the chamber containing spring 332 and thence to the outside of block 252. It will be understood that block 252 is contained in a casing or tank of oil so that oil may be vented or relieved therefrom to such casing or tank through passages leading from said block. Valve 33!] also controls passage 2522 with which connects conduit 25! which leads from decelerating valve 249.

Another valve 335 is disposed in block 252, the same being shown as acted upon at one end by a compression coil spring 331 which acts to move said valve to the right. Valve 335 controls passage 252m. extending from valve 282 and also controls passage 2521' which leads to valve 3H5. Valve 336 controls a vent passage 252aa shown as disposed at its lower side and is moved by pressure in a passage 252bb extending from its upper side, and in a passage 252cc extending from its upper side.

Another valve 340 is disposed in block 252 being shown adjacent the top thereof, which valve has an extension or rod projecting from casing 252 and equipped with a cam roller 34! engaging the flight level cam 23!. Valve 340 is acted upon by coil compression spring 342 tending to move the same to the left as seen in Fig. 3 or in a direction to engage cam roller 341 with cam 23!. Valve 340 controls passage 2521)?) and passage 25200. It also controls the passage 252@ which extends upward from valve 210 as well as controlling vent passages 252dd and 252cc.

A vent passage 252ff extends along one side of block 252 communicating with the valve chambers of valves are, 212, 216, 282, 33!] and 340. A

The valve 335 has two positions and is a snap action valve which is placed under tension or cooked by its cam 229. This cocking takes place approximately midway of the hoisting cycle and immediately after the initiation of the lowering cycle. The function of said valve is to supply pressure to or relieve pressure from the plunger of deceleration valve 249 at the proper time during the movement of said hoist.

Valve 34B is provided to admit fluid under pressure to the right hand chamber of the'valve 336 which could be called a shuttle valve, which pressure is admitted only at a flight level. At this time roller 36! enters a notch or depression 23la in cam 22! as seen in Fig. 3. It will be seen that valve 335 has pressure applied thereto as shown in Fig. 3 from line 249 through valve 218, then through passage 252 through valve 34!! and through passage 25200. The function of valve 336 in turn is to insure that fluid under pressure will be admitted to detent plunger 333 and to valves tit and 3l2 for withdrawing latches 3H and 3M only at a flight level. A by-pass creeper 22 valve 360 is mounted in valve block 248 controlling a passage 248m leading from the chamber of decelerator valve 249 to tank. Valve 360 may be adjusted as desired.

Referring again briefly to some of the valves described it may be stated that valve 210 which is manually operated when placed in power position, admits the liquid under pressure to the control assembly. lSaid valve is shown in its power position and it will be seen that the liquid under pressure from conduit 24!! can pass through valve 21!! to passage 252e which extends to valves 212 and to valve 340. When valve 210 is placed in manual position fluid from pressure in line 240 is cut off and pressure in the control system is relieved permitting spring I8l to engage clutch 152 and thus connect the hand power unit We to the power shaft 222 for operating the hoist. Positioning valve 212 in manual position while the hoist is running will cause no damage since the hoist motion will merely be braked through the above mentioned clutch 185. A further function of valve 216 is to unload or relieve the pressure from above or at the right of valve 264. This relief may be traced from said valve through conduit 251 through passage 25213 to and through passage 252d, around valve 210 now in manual position and to tank through passage 2520. This relieving or unloading of valve 264 prevents the building up of fluid pressure in the pump circuit when the hoist is being driven manually with the electric motor 42 running and the reversing valve 256 in centered position.

Valve 212 as stated has three positions determined by its control lever 213. With the control lever in step position as shown in Fig. 3 the hoist is inoperable regardless of the positions-of the other valves. When in power operation with the hoist running in either direction and the flights at any point of their travel throwing control lever 213 to stop position stops the hoist immediately and unloads the main line flow by unloading valve 234 causing it to open. This un loading may be traced through conduit 2551, passage 252t, passage 252d, through the chamber of valve 212 and through passage 252 to tank. With the main line thus relieved or unloaded the hoist is inoperable.

Valves 218 and 282 as stated are actuated from the lower and upper flight levels by the interlocked levers at the lower and upper flights respectively. With lever 21! in power position it is the positioning of valves 216, 282 and 212 in combination which causes an operating cycle to be initiated by admitting pressure to the plunger or to the left hand ends of valves 352 and 316. This pressure is admitted through the flight level shuttle valve 336 as already described, which is controlled bythe cam Zfi-liacting on valve 320. The flow of liquid under pressure to valves 312 and 3H5 and to detent plunger 333 may be traced from conduit 240, through passage 252a, around valve 213, through passage 252e, around valve 212 now in hoist position, upward through passage 25211 to valve 216 now in loaded position, around valve 216 and upward through passage 2521: to valve 282, around valve 282, upward through passage 252m to valve around valve 335 and down through passage 2521 to valve 3 Hi and through passage 252g to valve 3 l2. The fluid also passes from passage 252'! through passage 25211. to detent plunger 333. When valves 21%, 282 and 212 are in any one of the non-operating combinations they act to vent the line from valves 3l2 and 316. This venting-by valve 213 can be 23 traced from vent passage 252hh adjacent valve 216 through the chamber of said valve through passage 25212 through valve 282 through passage 252m through valve 336 and thence through passages 2521* and 252g to the pressure chambers ;of valves 352 and 3E6. As stated valve 216 is in .a position with its control lever 21'! at the position of lower flight empty so that a hoisting :cycle cannot be initiated.

Pressure operated valves H2 and BIG serve to disengage the latches 3M and 3! l as above described. These valves are linked to the unloading ilot valve 326 which functions to unload the main line pressure at the completion of a cycle .of movement of the hoist in either direction when the stop latch is engaged. Valve 32% cuts off the unloading line from valve 26d. This line extends from said valve through conduit 26? to passage 252i. As stated, the stops on cams 22 i and 228 and the latches Shi and 3H are arranged so that one of the cams is free to rotate in a direction .corresponding to hoist regardless of the position of its engaging latch the other cam is free to rotate in a direction corresponding to lowering the hoist regardless of the position of its engaging latch. Thus in order to have movement of the hoist in either direction it is necessary .to disengage the latchwhich would otherwise prevent rotation in that direction. In power operation both stop latches 3H and 3M are withdrawn simultaneously by the action of the rods extending from valves 3H5 and 352. In manual operation one or the other of said stop iatches are withdrawn by the action of the auxiliary hand lever .ill'.

The requirements for operation of the hoist are follows:

It may be stated that with the embodiment of the invention illustrated one practical use of the hoist contemplated is that of an ammunition or powder hoist on a war ship. The hoist is shown diagrammatically in Fig. 4. With ammunition units in both flight level stations, that is, at the upper flight 2H] and lower flight 2i i, the hoist is n perable. With both flights of the hoist empty the hoist is inoperable. With the lower flight or station loaded and the upper station or flight empty and the manual control lever 213 moved to hoist 'position, the hoist will operate to raise or move upward one cycle. With the upper station or flight loaded, the lower station or flight empty and the manual control lever 213' in its lower position the hoist will operate to move downward or lower through one cycle. With the hoist running in either direction (in power operation) throwing the manual control lever 213 to stop position, stops the hoist. This unloads the main line as has already been described.

'To initiate a cycle of movement of the hoist in manual operation, it is necessar that each of the three independently actuated levers, 215, 280 and 29!! be positioned in the proper combination. This is necessary to permit movement of the auxiliary hand lever 3| 1 which is used to initiate a cycle of movement of the hoist manually to become efiective in disengaging one or the other of the stop latches which in their engaged position prevent operation of the hoist. When an operating combination is obtained, such as, upper fl ht empty, lower flight loaded, and hand control lever 213 in its hoist position, movement of lever 3|! will move the extensions of one of the valves 3l2 and 316 and withdraw the proper latch 3M or 3. It will be seen that when lever 21'! is moved to its loaded position that this will rotate shaft 219 and move lever 28.0 clockwise so that its upper portion as shown in Fig. 3 will move to the right. When lever 213 is moved to hoist position it will swin lever 215 through the link 214 and will engage the lower end of lever .296, the latter being already positioned by the action of lever 290 as shown, to its extreme right hand setting. When lever 29!] is in an operative position as with the upper flight empty as shown in Fig. 3, its vertical extension also engages the lower end of lever 296. All three levers thus have their upwardly extending ends as shown in Fig. 3 moved to the right into engagement with the lower end of lever 295. This permits plunger 399 to swing the lower end of lever 29! to the right, moving said lever 29I in a counterclockwise direction, raising rod 292 and plunger head 294a to move plunger 294 through the aperture in block 3|2a. The plunger 294 now proj cts upwardly through the block 3 12a so that when lever 3 l l is swung in a counterclockwise direction the pin projecting from dog 32B movable over block 3I2a will engage the plunger 294 and move block 3 Ha to the right as shown in Fig. 3, thus moving stop latch 3M away from its cam 22'! and permitting rotation of power shaft 219 to operate the hoist. It will be understood that with lever 213 in neutral or stop position plunger 294 is not projected above block 3I2a. It will also be noted that plunger or pin 298 is withdrawn through block 3l6a by movement of upper flight lever 283. As soon as the ammunition unit which is being hoisted leaves the lower flight level, plunger 294 will be withdrawn below the top of block 3 l 2a by action of the lower flight level lever 27'! moving to its empty position, thus rotating shaft 27.9, swinging lever 280, moving lever 29l in a clockwise direction and pulling down on rod 292. Spring 353 can now move valve 3l2 and its extension to the left so that latch 3M will be in position to engage its cam 221 at the end of the cycle. Thus regardless of how the operator may subsequently move the auxiliary lever 3|? the extension of valve 3l2 will be in position to permit engagement of the stop latch M4 at the completion of the cycle.

In power operation as already stated the latches 3H and 3 are withdrawn by pressure being applied to valves Sit and M2 to move them to the right as shown in Fig. 3 and thus disengage latches 3| l and 3 Id. In Fig. 3 the parts are shown in position with the hoist inoperative. Manually operated lever 273 is as stated set in its stop position. Both flights of the hoist are empty and as stated, the main line is unloaded through valve 284, which unloading line has been previously traced. The main line is also unloaded due to the position of pilot valve 326 as well as the position of hand control valve 212. Both of the stop latches 3H and 3 are engaged with their respective cams 228 and 227. Line 309 from the clutch I86 in hand drive unit .1 F6 is vented to tank through conduit 3139, around valve 306, passage 2522', around valve 276, passage 252k, through the chamber of valve 212 and through passage 252) to tank. Pressure from line 24!) to the control system is blocked by valve 212, blocking passage 252e. Reversing valve 256 is in centered position, both lines to the pressure chambers at the ends thereof being vented to tank. The ventin from one side of the valve takes place through conduit 253, passage 2527', around valve .216, passage 252g, chamber of valve 272 through passage 252 to tank. The venting from the other side of the valve occurs through conduit 262, through passage 2521', around valve 27.5,

. pling around valve 210,

passage 2487' into through passage 25272. to valve 212 and through said valve and passage 2521 to tank. Deceleration valve 249 is in closed position, shutting off passage 248a. The line 251 extending to the pressure chamber of deceleration valve 249 is vented through passage 2522, through valve 336 and through passage 252w to tank. The motor 42 is running as is pump 43, valve 236 is open and valve 241 is closed. The pilot 239 and its spring 238 which controls the opening of this valve has been set to the pressure required for acceleration of said hoist, which in one embodiment in practice was about 600 pounds.

To initiate the cycle of movement of the hoist in power operation, lever 213 is moved to hoist position. As stated, the lower flight must be loaded and lower flight valve lever 211 and its valve 216 are thus moved to loaded position. Also as stated, upper flight level must be empty and thus the upper flight lever 283 and its valve 282 are at the empty position or the valve will move to its normal right hand position. Shuttle valve 306 will move to its right hand position admitting liquid under pressure to line 309 which will .be transmitted to will disengage clutch 186 so that the hand drive unit is disconnected from the output shaft. This liquid under pressure is delivered to conduit 309 from conduit 24!], through passage 252a, around valve 210, through passage 252e, around valve 212 now moved to the right to its hoist position, through passage 252h to valve 216 now in its loaded position, around said valve and through passage 2522' to shuttle valve 366 and through said valve to conduit 309. With the valves 340 and 336 in the position shown in Fig. 3 liquid under pressure is admitted to the detent plunger 333 and valves 312 and 316 as soon as an operative combination of the three valves 212, 216 and 282 is obtained. As above explained, a cycle can only be initiated when such as an operative combination is obtained. With the levers 213, 211 and 263 in the positions described pressure is admitted to valves 312 and 316 through passages 2521" and 252q and pressure is admitted to detent plunger 333 through passage 252u as above traced and valves 312 and 316 move to the right disengaging latches 314 and 311. Valves 312 and 316 have thus moved to the right and through cou- 326a have moved valve 326 to the right. Valve 326 thus has cut off passage 25225 which communicates with conduit 261. Said conduit is thus closed off and with valve 212 in hoist position any pressure to conduit 261 is also cut ofi. Conduit 261 is thus closed and this allows pressure to build up on top of or at the right of valve 264 as seen in Fig. 3 and valve 264 is moved to closed position. This cuts off passage 248k: so that fluid under pressure is delivered to the main line and to hydraulic motor 215. Pressure is supplied from pressure conduit 246 through passage 2520., through passage 252e, around valve 2'12, into passage 2521i, around valve 216, to passage 2522' and into conduit 262 to the right of valve 256. This moves valve 256 to the left, the release from the left side of said valve occurring through conduit 263, passage 2527', around valve 216, through passage 252g and around valve 212 through passage 252) to tank. With valve 264 closed, fluid from the pressure line goes into passage 248i and into passage 2481i. The valve 256 being in hoist position, the fluid then goes from line 248 and into conduit 260 and to the hydraulic motor 215. Returning from the motor, the fluid goes through conduit 261 into passage 24811. and into passage 248d through the hand drive unit 116 and L 26 exit path, through the decelerating valve 246 and back to tank. A cycle is thus started. When this occurs cam 231 moves the extension rod of valve 340 to the right and this admits liquid under pressure to the left hand side of valve 336'. This pressure line can be traced from pressure conduit 2416, through passage 256a, around'valve 216, through passage 2526 to the top of valve 340, through said valve to passage 2521)?) and thus to the leftof valve 336. .Valve 336 thus moves to the right and this relieves pressure on the valves 312, 316 and the detent plunger 333 through passage 252? with which passage 25214 from said detent plunger connects, around valve 336 now moved to the right and out through passage 252aa. Valves 312 and 316 can thus be moved to the left by their springs and position latches 311 and 314 so that they will be again engaged when cams 226 and 221 arrive at the proper position. Reversing valve 256 will be moved to its left hand position in response to the setting of valve 212 in its hoist position. Pressure on the right of reversing valve 256 can be traced through conduit 262 to passage 252i, around valve.216 now in its loaded position, around valve 212 now in its hoist position and around valve 210 in its power position as shown in Fig. 3 to pressure conduit 246. It may be stated that spring 332a moves valve 336 to the left when detent plunger 333 is acted upon by pressure through passage 252a, so that vent passage 252w is cut off and pressure from 2521) is admitted to passage 2522 and conduit 251 to move valve 249 to the left. Decelerating valve 249 is thus open as pressure is applied to its right hand end from passages 25211. and 2522) around valve 330 through passage 252a and conduit 251 and the flow through the power line from conduit 243 through passage 2842', through reversing valve 256 as stated in its left hand position, through passage 2487', passage 248g through conduit 260 to motor 215, through conduit 26! from the motor through the reversing valve 256, through passage 24801, through the chamber of valve 253 and passage 248d through the decelerating valve 249 now moved t the left from its position in Fig. 3, through conduit 244 to tank 41, is unrestricted and the hydraulic motor 215 is free to operate and the hoist is operated. As soon as the ammunition unit leaves the lower flight, valve 216 will be shifted to the position shown in Fig. 3. As the hoist moves valve 330 will be cooked in mid-cycle by its cam, detent plunger 333 moving into recess 336a. When this valve is in this position pressure is relieved in the pressure chamber or at the right hand end of decelerating valve 249. This relief takes place I through conduit 251, passage 2522, around valve 336 and out to tank through passage 252w. The spring 256 is thus put in control of valve 249 to cause the deceleration as permitted by cam 236. The, said relief occurs at a point where cam roller 246 is at the high side of cam 230 so that deceleration is delayed by the cam until the proper point in the operating cycle. As the hoist reaches the end of the cycle, valve 340 will take the position shown in Fig. 3 as cam roller 341 will drop into recess'231a. This will again permit a.

new operating cycle to be initiated as above described when the proper combination of valves 212, 216 and 282 is again obtained. As the hoist comes to the end of the cycle the lowergstop latch 3i 1. will drop off the high side of its cam 228 and this will permit movement of valve 316 under the influence of spring 324 which will allow valve 326 to move to the position shown in 27 Fig. 3 under the action of spring'321. Valv'es3'l2 and 3|6 are under control of springs 3|3 and 324 respectively as previously set forth in the description of the initiation of a cycle. This relieves pressure on valve 26 which will open and unload the main line through passages 2487', 248k and conduit 244. The hoist thus again comes to stop position. If the load is removed from the top flight another load placed on the lower flight and lever 2'73 left in hoist position, another cycle will be immediately instituted which will take place as above described.

To initiate a lowering cycle of movement of the hoist the operation is much the same as described except that hand lever 213 will be set for its lower position, lever 283 will be in loaded position and lever 2?? will be in empty position. With this combination pin plunger 298 will be projected through block 3115a and a cycle can be initiated manually by swinging lever 3H. The projection on dog 320 movable over block 3I6a will engage pin 2%, move said block and withdraw latch 3i I permitting movement of the hoist in a direction to lower. With hand lever 213 in lower position valve 2l2 will direct liquid under pressure to-the left hand end of reversing valve 256; This liquid under pressure will be transmitted'from conduit 240 through passage 252a, through valve 2min power position, through passage 2'52e to and through the valve chamber of valve 272 now in its lower position, through passage 252g to and through valve 276, through passage-252gi to conduit 263 to the left hand end of reversing valve 255. Valve 216 will be moved to its empty position since to lower the hoist the lower flight must be empty. Valve 282 will be moved-toits left hand position or with lever 283 in loaded position, since to lower the hoist the upper flight must be loaded. Owing to the position of valve 272' no liquid under pressure is admitted to the pressure chamber of decelerating valve 249 through conduit 25!. The valve 369 will be opened suflioiently to allow slow speed rotation of' the hydraulic motor 2l5 even with decelerationvalve 249 completely closed off. The valves 212, 2? and 282-wi11 be brought to an operative combination by their levers being moved to the positions just above mentioned. Pressure is-adn'iitted through conduit 2%, passage 252a, around valve 270 to passage 2526 around valve 212 to passage 2525;, through slots 215a to passage 2521c; around valve 282 (now in loaded position) into passage 2520, around valve 335 to passage 252r and passage 2'52q to the left end of valves 356 and 3! 2 to withdraw the latches 3H and 3 |fi se that the cycle is initiated. The deceleration valve 2 l9will be gradually opened by its earn 236. The return flow from the hydraulic motor will pass through the adjustable foot" valve 253. This in combination with the gradualopening of the valve 259 prevents undue acceleration of the hoist in its lowering movement. The function of the remaining valves in th'ecycle of lowering is similar to that already described for the cycle of hoisting.

The cycle oflowering movement for the hoist can,.of' course, be initiated by power as above described or by use of the hand power unit I16. If the hoist isto be lowered manually, lever 2H will be moved to its manual position thus cutting oif liquid under pressure to the control assembly byshutting off conduit 240. This as already described cuts off liquid under pressure to conduit sflfl permitting engagement of clutch I86 in the hand drive unit so that said unit is connected to output shaft 2H3; With an operating compine-tion placing levers 215; 229 and: 290in 'an operative combination, auxiliary hand lever 3|! can be moved as" already describedfor releasing one or the other of the latches 3H or 31$. In a manual lowering cycle circulation of fluid in' the hydraulic motor 2454s restricted to a degreedetermined by the adjustment of foot valve 253'; restriction is imposed as it is desirable to have a back torque in the hydraulic motor 215 when lowering to insure quiet operation of the hand drive unit.

The cam 229 has a high portio'nfor the greater part of its circumference adapted'to engage cam roller 33!. As above stated valve 330 is put under tension er cockedby cam 229 in mid-cycle and is h'eld'so by plunger 333. With valve 330 in this position the pressure chamber of decelerating valve 229 is vented to tank through conduit 25! as above described. Pressure is only admitted to the pressure line from conduit 24%] through passage 252a and upward through passage 2521; and to the decelerating valve when lever 273 is in' its hoist position and" the conditions to initiate a cycle as previously set forth, are present. This means that valve E72 must be in its hoist'position so that passage 252e will be connected to passage 252. 1, valve 2% must be in its loaded position so that passage 2527i is connected to passage 2521a, valve 282 must be in its empty position so that passage 25211 is connected to passage 252m, valve 236 must be movedto the left so that 252m is connected to passage 2521' leading to passage 252a to lift plunger 333 and thus permit spring 332a to move valve 333'to the left to connect passages 25212 and 252s, and valve 340 must be in its left position as shown in Fig. 3 before valve EEG is moved to its left position by fluid admitted through passage 252e, valve 340 and passage 25200 to move valve 335 to the left. Should the hoist be running in a lowering direction'and be reversed by the lever 213 being moved to hoist position pressure will be admitted through the line as above indicated to decelerating valve 249, moving it to its left hand position and allowing unrestricted flow through the hydraulic motor 215 and to tank. Under such conditions if valve 338 were notcontrolled the hoist would wheel into the mechanical stops of cams 22? and 228 at full speed. To prevent this the high portion'is provided on cam 229 so that if the timing shaft 226 revolves through a comparatively small arc this will be sufllcient to move valve 339 and cut off the pressure to decelerating'valve 228. This valve will then be acted on by its spring 250 and the hoist can move no faster than permitted by the decelerating valve and the creeper valve 368. In the lowering cycle pressure goes from pressure line 24!) through passage 252a, around valve 210, passage 252e, around valve 25'2 into passage 2529, through passage 2527c, around valve 282 (now in loaded position) into passage 2520 to passage 252m through the chamber of valve 336 through passage 2527 through passage 252a. As soon as pressure is present in passage 252a, plunger 333 lifts and valve 338 is moved to the left by spring 332a.

From the above description it will be seen that we have provided a very compact,-eflicient and quickly operating control for a hoist. The movement of the hoist is controlled with great precision. As pointed out in the description it is impossible for the hoist-to operate until the desired operating conditions are present. The hoist may be changed from power drive to manual drive at will as described and can be started either-with a hydraulic control or bythe au-XiIia-ryhand con- 29 trol. The movement of the hoist is accurately decelerated as described. A cycle of movement of the hoist as will be apparent from the preceding description embodies the movement of the hoist from the time it is started until it is stopped.

The control system has been amply demonstrated in actual practice, found to be very successful and efficient and is being made for actual use. I

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

1. A control system for a hoist having a lower flight position and an upper flight position having in combination, a hydraulic motor connected to said hoist for driving the same, means for supplying fluid under pressure to said motor to operate the same, an output member driven by said motor, a hand drive unit by which said output member may be actuated, a clutch for connecting said hand drive unit and said output member, means normally holding said clutch engaged, a hydraulic control unit for said hoist including a member movable to power and manual positions, said hydraulic control unit acting with said first mentioned means when said member is moved to power position to release said clutch so that said hoist may be driven from said hydraulic motor and acting when said member is moved to manual position to permit operation of said hand drive unit.

2. A hydraulic system for a hoist having in combination, a hoist movable through a cycle from an upper flight to a lower flight and vice versa, a hydraulic motor directly connected to said hoist for moying the same, a pump for supplying fluid to said hydraulic motor, an electric motor for driving said pump, a hydraulic control unit including a reversing valve for reversing .the direction of flow of liquid through said motor for reversing the movement of said hoist in successive cycles, a manually operated control lever, control elements operated from said flights respectively cooperating with said control lever'to initiate a cycle of said hoist when said control lever and control elements are in definite combinative positions, means for setting said reversing means in accordance to whether said hoist moves in one direction or the other and means for stopping the movement of said hoist at the end of a cycle.

3. A hydraulic control system for a hoist having a lower flight position and an upper flight position having in combination, a hydraulic motor connected to saidhoist for driving the same, means for supplying fluid under pressure to said motor for operating the same, an output member driven by said motor, a hand drive unit for said hoist adapted to be connected to said output member, a manually operative clutch for connecting said hand drive unit and said output member and a hydraulic control unit including means operated by said first mentioned means for hydraulically rendering said clutch inoperative for disconnecting said hand drive unit and output member when said hoist is operated by said motor,

4. A hydraulic control system for a hoist having upper and lower flight positions and movable through a cycle to move fro m one of said posi tions to the other having in combination, a hydraulic motor directly connected with said hoist for moving the same, a motor driven pump for supplying fluid .to said motor, means connecting said pump and motor including a hydraulic control unit, a member movable to hoist and stop positions, control member movable from said hoist cooperating with said last mentioned member to initiate a cycle of movement of said hoist,

a valve in said hydraulic control unit for causing deceleration of said hoist as it approaches the end of a cycle and means driven from said hydraulic motor cooperating with said decelerating valve to control the deceleration of said hoist.

5. A control system for a hoist having upper and lower flight levels and movable through a cycle from one .to the other having in combination, a hydraulic motor connected to said hoist for moving the same, a pump for supplying fluid to said motor, an electric motor for driving said pump, a haft driven from said hydraulic motor, a timing shaft driven from said first mentioned shaft, fluid conducting means connecting said pump and motor including a hydraulic control unit for controlling movement of said hoist and including a decelerating means, automatic means for moving said decelerating means and a cam on said timing shaft cooperating with said automatic means to controi said decelerating means.

6. A hydraulic control system for a hoist adapted to be operated in successive cycles respectively to move between upper and lower flight positions having in combination, a hydraulic motor directly connected with said hoist for driving the same, a motor operated pump for supplying fluid to said motor, a power shaft driven by said motor, a timing shaft driven from said power shaft, fluid conducting mean including a hydraulic control unit for governing supplying of fluid to said hydraulic motor also including a reversing valve, a pilot valve for directing fluid to either end respectively of said reversing valve and a member driven from said timing shaft for placing said pilot valve under tension during a cycle of movement of said hoist to move to another position upon initiation of the next cycle .to properly position said reversing valve for said next cycle of movement of said hoist.

7. A control system for a hoist having upper and lower flights comprising a hydraulic motor for driving said hoist, a stop means for preventing movement of said hoist, means for supplying fluid under pressure to said motor including a hydraulic control unit having a manually operated control member movable to hoist and stop positions, a second manually operated control member movable to power and manual positions, means operated by said hydraulic control unit to release said stop means when said second manually operated member is in power position and an auxiliary manually operated means for releasing aid stop when said first mentioned manually operated member is in hoist position,

8. A control system for a hoist having a lower flight position and an upper flight position and movable through a cycle from one of said positions to the other having in combination, a hydraulic motor connected to said hoist for driving the same, a stop means preventing movement of said hoist, a manually operated member adapted to release said stop means to initiate a cycle of movement of said hoist and means for supplying fluid under pressure to said motor for operating the same including a hydraulic control St unit for releasing said stop means to initiate a cycle of movement of said hoist.

9. A control system for a hoist having a lower flight position and an upper flight position and movable in a cycle from one position to the other having in combination, a hydraulic motor connected to said hoist for driving the same, a member movable for manually initiating a cycle of movement of said hoist, a second member movable to hoist or stop positions, a control element at said lower flight movable to positions to permit or prevent the initiation of a cycle of movement of said hoist according to whether said flight is loaded or empty, a second control element at said upper flight movable to positions to permit or prevent initiation of a cycle of movement of said hoist according to whether said upper flight is loaded or empty and means rendering operable said first mentioned movable member to initiate a hoisting cycle of movement when said second member is movable to hoist position, said first mentioned control element is in loaded position and said second mentioned control element is in empty position and means for stopping said hoist at the completion of a cycle.

10. A hydraulic system for a hoist having in combination, a hydraulic motor connected to said hoist for moving the same, a driven pump for supplying fluid to said hydraulic motor, fluid conducting means connecting said pump and motor including a hydraulic control unit including a decelerating valve, means normally urging said valve in one direction to cause deceleration of said hoist, means driven from said motor acting on said valve and cooperating with said second mentioned means to control the movement thereof for decelerating said hoist and means for controlling the delivery of fluid to said valve to move said valve to non-decelerating position including means driven from said hydraulic motor.

11. A hydraulic system for a hoist having in combination, a hydraulic motor connected to said hoist for moving the same, a driven pump for supplying fluid to said hydraulic motor, fluid conducting means connecting said pump and motor including a hydraulic control unit which includes a decelerating valve, means normally urging said valve one direction to decelerate said hoist, means driven from said motor acting on said valve and cooperating with said second mentioned means to control the movement thereof for decelerating said hoist, a second valve for controlling fluid delivered to said first mentioned valve for moving it to non-decelerating position, means normally urging said second valve in one direction and means driven from said hydraulic motor cooperating with said last mentioned means to control the movement of said second valve.

12, A hydraulic system for a hoist movable in a cycle from an upper to a lower flight position and vice versa having in combination, a hydraulic motor connected to said host for moving the same, means for supplying fluid under pressure to said motor including a hydraulic control unit which includes a reversing valve, a control valve for said reversing valve, means for moving said control valve during a cycle of movement of said hoist to place the same under stress tending to move it to one position, means for holding said control valve under said stress and means operable near the end of said cycle for permitting movement of said control valve under said stress to direct fluid to one end or the other bination, a hydraulic motor connected to said hoist for driving the same, means for supplying fluid under pressure to said motor for operating the same, an output shaft driven from said motor, a stop cam on said shaft, a latch cam on said shaft, a stop engaging said latch cam and preventing movement of said shaft and hoist, means for moving said stop to permit movement of said shaft and hoist, a plurality of levers movable to positions respectively to permit and to prevent the operation of said last mentioned means and a plurality of means including means depending on the position and loaded condition of said hoist for moving said levers to positions respectively to permit operation or" said means for moving said stop, means for conducting fluid to said motor when said stop is so moved and a stop latch for engaging said stop cam at the end of said cycle to stop said hoist at the completion of a cycle.

14. A hydraulic control system for a hoist, which hoist has upper and lower flight positions, a hydraulic motor for driving said hoist, a driven pump for supplying fluid to said motor, fluid conducting means connecting said pump and motor, a member driven by said motor, a stop engaging said last mentioned member to prevent operation of said hoist, a member movable to positions according to Whether the lower flight is loaded or empty, a control member movable to hoist and stop positions, means for releasing said stop, a manually operated member for actuating said last mentioned means, a hydraulically operated member for actuating said last mentioned means, said means being operable only when said control member is moved to hoist position and when said second mentioned member is in position to which it is moved by the lower flight being loaded.

15. A control system for a hoist, which hoist has a lower flight position and an upper flight position and is movable from one position to the other during a cycle of operation, having in combination, a hydraulic motor connected to said hoist for driving the same, means for conducting fluid under pressure to said motor for driving the same, a stop preventin operation of said hoist, a member movable to release said stop, a control element for controlling the operation of said member, means located at one of said flights for controlling the position of said control element, a second control element for controlling the operation of said member, means located at said other flight position for controlling the position of said second control element, whereby said member connot operate to permit said first mentioned means to operate until said elements are in positions respectivel to permit said member to be moved to release said stop.

16. A control system for a hoist having a lower flight position and an upper flight position and movable through a cycle from one position to another, having in combination a hydraulic motor connected to said hoist for driving the same, means for supplying fluid under pressure to said motor, a control member normally urged to a position to prevent operation of said hoist but movable to position to permit operation of said hoist, a plurality of control elements cooperating with said member to determine its position,-

'ineans at one of said flights for controlling one -of said elements to determine the position of said member, depending on Whether said hoist is unloaded at said last mentioned flight whereby 'said hoist cannot operate until the proper loaded and unloaded conditions are present for positioning said control elements to permit movement ofsaid control member and operation of said first mentioned means.

17. A control system for a hoist, which hoist has a lower flight position and an upper flight position and is movable from one position to the other during a cycle of movement having in combination, a hydraulic motor connected to said hoist for driving the same, means for supplying fluid under pressure to said motor including a hydraulic control means, a deceleration valve forming part of said control means, resilient means acting to move said valve in one direction, and a cam cooperating with said means for controlling the position of said valve and the degree ofdeceleration of said hoist.

18. The structure set forth in claim 17 and fluid operated means for moving said valve in the opposite direction to open position during the first part of said cycle.

19. A control system for a hoist, which hoist has a lower flight position and an upper flight position and is movable from one position to the other during a cycle of movement having in combination, a hydraulic motor connected to said hoist for driving the same, means for supplying fluid under pressure to said motor including a hydraulic control means, a fluid operated reversing valve movable to positions respectively to direct fluid in one direction or the other to said r motor, a second valve for controlling the supply of fluid to said reversing valve, means for moving said second valve during said cycle, and placing the same under spring pressure, means for holdhas a lower flight position and an upper flight position and is movable from one position to the other during a cycle of movement having in combination, a hydraulic motor connected to said hoist for driving the same, means for supplying fluid under pressure to said motor includ ing a hydraulic control means, said hydraulic control means including a valve, means connected to said valve for moving the same andhaving a position for manual operation of said hoist and a position for power operationof said hoist, a second. valve, means connected to said second valve for moving the same and having a hoist position and a stop position, a third valve, means connected to said third valve for moving the same and disposed at the lower of one of said flight positions and adapted to be operated to ,loaded and empty positions, a fourth valve, means connected to said fourthvalve for'moving the same and having a portion disposed at the upper of said flight positions adapted to be moved to loaded and empty-positions, and means preventing operation of said hoist until said first mentioned valveis moved .topower position,

34 said second valve is movedto hoist,.position, said portion at said lower flight is moved to loaded" position and said portion atsaid upper flight is moved to empty position;

21. The structure set forth in claim 20,'a cam,

- a start latch engaging said cam preventing starting of said hoist, a manually operated means for -moving said start latch .away from said cam to permit operationof said hoist, and means rendering said last mentioned means operative when said means connected to. said firstv mentioned valve is moved to manual position.

22. The structure set forth in claim 20, a hand driving unit for said hoist includinga clutch, means 'normallyholding said clutch iniengaged driving position, and fluid operated means for moving said clutch to disengaged position when said means connected to said flrst mentioned valve is moved to power position.

23. A control system for a hoist, which hoist hasa lower flight position and an upper flight position and is movable from one position to the other during a cycle of movement, having in combination a hydraulic motor connected to said hoist for driving the same, means for supplying fluid under pressure to said motor, a start latch cam, a stop latch cam, a start latch adaptedto engage said start latch cam, a stop latch adapted to engage said stop latch cam, fluid operating means for moving said start latch away from its cam to permit movement of said hoist, meansfor moving said stop latch away from. its cam, and means on said stop latch engaging said start latch for holdin the latter away from its cam.

24. A hydraulic control system for a hoist having in combination, a hydraulic motor constructed and arranged to be directly connected with said hoist for moving the same and having a power output member, a driven pump for supplying fluid to said motor, a hydraulically controlled means, a hand drive unit for said hoist adapted to be connected to said output member, a control lever movable to power and manual positions, said hand drive unit comprising a clutch, means normally r holding said clutch in engaged position, a'member movable by said control lever when moved to power position to supply fluid to said hydraulic control means to disengage said clutch and movable when said control lever ismoved to manual position to cut off'fluid: to said hydraulic control means and permit engagement of said clutch, so that said hoist can be manually operated.

25. 'A control system for a hoist having a lower flight and an upper flight position having in combination, a hydraulic motor connected to said hoist for driving the same, astop-preventing operation'of saidhoist, means for moving said stop to' permit operation of said'hoist, a plurality; of control elements, means at one flight of' said hoist for controlling one of said elements and moving the same to positions either to permit'or prevent movement of said'stop, means atsaid other flight for controlling another of said elements and movingthe same 'to positions either 5 to permit or prevent movement of said stop,

means for' actuating said first mentioned means operative only when said control'elements'have been moved to positions permitting'movement of said stop, and means for supplying fluidu'njder pressure to said motor to operate said hoist when pump for supplying fluid under. pressure .for said

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