US3656294A

US3656294A - Hydraulic control device

Info

Publication number: US3656294A
Application number: US797594A
Authority: US
Inventors: Pierre A Praddaude
Original assignee: Poclain SA
Current assignee: Poclain SA
Priority date: 1968-02-07
Filing date: 1969-02-07
Publication date: 1972-04-18
Anticipated expiration: 1989-04-18
Also published as: JPS5114666B1; ES363363A1; GB1256629A; FR1604145A

Abstract

An hydraulic control device which can be used particularly for the control of a winch driven by an hydraulic motor, having two slide valve distributors, whose slide valves are subjected to the action of a spring to position them in a rest position. The slide valves are each capable of occupying two positions and are coupled to a single operating lever. A first distributor situated in a duct ensures the permanent opening of the duct in the rest position while the second distributor situated in series with the first, is of the reversing device type and places the first distributor in selective communicating with two other ducts connected respectively to a source of fluid under pressure and to a discharge reservoir. The rest position of the second distributor corresponds to the connection of the first with the reservoir. The slide valve of the first distributor is coupled on the one hand to a single acting ram supplied by the fluid conveyed between the first and the second distributor.

Description

United States Patent Praddaude [451 Apr. 18, 1972 [54] HYDRAULIC CONTROL DEVICE 3,253,613 5/1966 Richolt ..137/625.69 3,274,779 9/1966 Klein ..9l/420 [72] praddaude 3,426,648 2/1969 Fehlings ..91/420 [73] Assignee: Societe Anonyme Poclain, Le-Plessis-Bel- Primary Examiner-Paul E. Maslousky leville, Oise, France Attorney-Mason, Fenwick & Lawrence [22] Filed: Feb. 7, 1969 [57] ABSTRACT [21] Appl 797594 An hydraulic control device which can be used particularly for the control of a winch driven by an hydraulic motor, having [30] Foreign Application Priority Data two slidevalve distributors, whose slide valves are subjected to the action of a spring to position them in a rest position. The Feb. 7, France slide valves are each capable of occupying v0 positions and are coupled to a single operating lever. A first distributor situ- [52] 11.8.0 ..60/1,9l/42(l)53/1g262, med in a duct ensures the permanemopening ofthe duct in the rest position while the second distributor situated in series 22 ifi 'ms 55 148: with the first, is of the reversing device type and places the 1 1e 0 91/146. 1372625 60/1 first distributor in selective communicating with two other ducts connected respectively to a source of fluid under pressure and to a discharge reservoir. The rest position of the [56] References cued second distributor corresponds to the connection of the first UNITED STATES PATENTS with the reservoir. The slide yalve olt" the first distributor is coupled on the one hand to a single acting ram supphed by the 1; 6 g fluid conveyed between the first and the second distributor. or 1115 2,964,908 12/1960 Pomper et al ..91/446 12 Claims, 2 Drawing Figures PATENTEUAP 18 I972 INVENTOR Piazza APQAbu-AuoE wasg'u A- 7 ATTORNEYS It is known that certain hydraulic motors and in particular winch motors are subjected permanently to a couple in a definite sense by reason for example of the existence of a load at the end of the winch cable. Thus in operation four phases are produced which can be summarized as follows:

1. Stopping and, possibly, locking.

2. Controlled rotation in a first sense (lifting).

3. Controlled rotation in the second sense (controlled lowering).

4. Free rotation in the second sense (free lowering).

Hydraulic distributors have already been thought of having four positions ensuring these four phases of operation. However, in the position of free lowering" which is often called the float position, it is necessary to provide a speed limiter, constituted by a calibrated valve or preferably by a valve driven by the pressure of the fluid delivered by the pump. At any rate, in these known arrangements when the motor is in the stop position the fluid delivered by the pump must pass through the speed limiter valve: thus a wastage of power results.

Thus the present invention has for its object a hydraulic control device for this kind of motor, or more generally receiver, particularly applicable to the control of winch motors.

According to the invention it comprises two slide valve distributors, the slide valves of which subjected to the action of a spring restoring them to a position, called the rest position, are each capable of occupying two positions and are coupled to a single operating lever. A first distributor situated in one duct ensures the permanent opening of the said duct in the rest position and, of course, its closing in the other position.

The second distributor of the reversing device type, is in series with the first distributor and places it in selective communication with two other ducts connected respectively to a source of fluid under pressure and to a reservoir.

Finally, the slide valve of the first distributor is coupled to a single acting ram supplied by the fluid conveyed by the duct connecting the first distributor to the second.

When the control device is used for the control of an hydraulic receiver, motor or ram, the movement of which can be effected in two opposite senses, the two supply conduits of the receiver are arranged in parallel on the first distributor.

As will be shown further on, these arrangements make available a control having four positions, one phase in the operation of the receiver corresponding to a movement which is effected under the action of an external force.

Furthermore the invention will be better understood and certain other characteristics will become apparent in the course of the description of one embodiment given solely by way of example with reference to the accompanying drawing in which:

FM. 11 illustrates a diagrammatic view of a device in accordance with the invention;

Fit 2 illustrates a diagram of the connections of the device in the case of its application to the control of a winch motor, the different parts being in the position corresponding to the stop position of the motor.

Referring to the drawing, it can be seen that the device comprises essentially two slide valve distributors l and 2 arranged in series in a duct 3. The slide valves lie and 2a of these distributors are coupled to a control lever t through a pivot point do and through a guide rod hinge db. On the other hand these slide valves, capable of occupying two positions, are subjected to the action of springs 5 which restore them into their rest position and which is that illustrated in the drawing in full lines. However, the slide valve la is furthermore shaped at its free end to form a piston operating in a cylinder ti, the assembly thus constituting a single acting hydraulic pilot ram acting against the corresponding spring 5 and supplied through a duct 7 connected to the duct 3 between the two distributors.

The distributor 1 permits selective closing of the duct 3 but, in its rest position, ensures the permanent opening of this duct. On the other hand, the distributor 2 is of the reversing device type and permits selective communication between the duct 3 and one of the two

ducts

8 and 9 which lead respectively to a source of fluid under pressure, for example a pump ll) which can be seen in FIG. 2, and to a discharge reservoir ill. in the rest position of the distributor 2, the duct 3 is in communication with the duct 9 and the reservoir 11. Referring more particularly to FIG. 2, it can be seen that the application of a device in accordance with the invention to the control of an hydraulic winch motor 12, or more generally of a receiver, the

"

supply ducts

13 and 14 are connected on the one hand to the duct 3 and on the other hand to the: distributor ll. However, it must be noted that the duct 13 whose fluid supply under pres sure corresponds to the rotation of the motor in the sense of lowering of the load, is connected between the two distributors l and 2.

Beyond the distributor l the duct 3 is connected to the duct 8 between the pump 10 and the distributor 2. Furthermore a non-return valve 15 is arranged in this portion of the duct 3 and only allows the passage of fluid coming from the pump.

Finally a tapping 16 is connected to the duct 3, after the distributor 1, this tapping being connected to the reservoir duct 9. It contains a pilot valve 17 controlled in a quite normal fashion, by fluid pressure at a predetermined location. In this case, the duct 18 forcontrolling this valve 17 is connected to the duct 3 between the distributors l and 2. The fluid can only pass the valve 17 towards the reservoir llll if the pressure in the duct 18 is suti'icient.

In the operation of the embodiment of the invention illustrated in FIGS. 1 and 2, when the control lever Al is in the position as illustrated by the solid lines in FIG. 1, so that distributor 1 is in the open position and distributor 2 communicates fluid line 3 with fluid discharge line 9 as illustrated in FIG. 2, fluid under pressure will flow from the pump ll) through fluid line 8, the portion of fluid line 3 interconnecting fluid line ti and distributor 2 which includes one-way valve 115, distribu tors 1 and 2, and fluid discharge line 9, into the reservoir ill. Under such conditions, fluid under pressure will be bypassed through the distributor 1 and will not be supplied to the fluid motor 12 to operate the motor in either forward or reverse drive. In addition, the valve 17 will remain closed, and the winch operated by the fluid motor 12 will be inactive.

When it is desired to operate the winch to lift a load, control lever 4 is pivoted about the pivot point 4b to the position A as illustrated in FIG. 1, whereupon distributor 1 closes and distributor 2 continues to communicate the portion of fluid line 3 interconnecting distributors 1 and 2 with fluid discharge line 9. Under such circumstances, pump 10 supplies fluid under pressure through fluid line 8, the portion of line 3 interconnecting fluid line 8 and distributor I, and fluid line lid to operate fluid motor 12 in the reverse direction thus causing the winch to rotate and provide a lifting action. Fluid is returned to reservoir 11 from fluid motor 12 through fluid line 13, the portion of fluid line 3 interconnecting distributors l and 2, distributor 2 and fluid discharge line 9. During this phase of operation of the control system, the valve 17 remains closed.

If then it is desired to utilize the winch for lowering a load, control lever 4 is moved to the position B as illustrated in FIG. 1 so that distributor 1 is in the closed position and distributor 2 functions to communicate fluid line 8 with the portion of line 3 interconnecting distributors 1 and 2. Under these conditions, pump 10 will supply fluid under pressure through fluid line 8, distributor 2, the portion of fluid line 3 interconnecting distributors l and 2, and fluid line 113 to fluid-motor 12 to operate the motor in forward drive. When fluid is applied to fluid line 13, fluid under pressure will be supplied to the end of distributor 1 through the fluid line 7 to urge the sliding spool of distributor 1 in the closed position. A predetermined amount of pressure in fluid line 3 between distributors l and 2 also will apply a sufficient pressure to line 18 to open valve 17'.

The opening of valve 17 permits fluid to return from fluid motor 12 through fluid line 14, a portion of fluid line 3 interconnecting

fluid lines

14 and 16, and fluid line 16 to the reservoir 11. In this phase of operation, the speed of the fluid motor 12 can be controlled by regulating the distributor 2. The pressure in fluid line 3 between distributors l and 2 will vary the pressure applied to valve 17 and thus regulate the return of fluid from the motor 12. The valve 17 thus may function as a speed regulator when the control system is operated to lower a load.

Finally, when it is desired to freely lower the winch load, the control lever 4 is moved to position C as illustrated in FIG. 1 to open distributor 1 and cause distributor 2 to communicate fluid line 8 with the portion of fluid line 3 interconnecting distributors 1 and 2. Under such conditions, fluid under pressure will be supplied to the fluid line 18 through distributor 2 and the portion of line 3 interconnecting distributors 1 and 2, to open valve 17, thus permitting fluid under pressure to circu late through fluid line 8, the portion of fluid line 3 including one-way valve and fluid line 16, to reservoir 11. Simultaneously, fluid in the fluid motor 12 will be caused to circulate freely through fluid line 13, the fluid motor 12, fluid line 14 and that portion of fluid line 3 including the distributor 1.

From the above description of the operation of the embodiment illustrated in FIGS. 1 and 2, it will be appreciated that by simple manipulation of the control lever 4 into the various positions as illustrated in FIG. 1, the fluid motor 12 may be operated to hold, lift, lower at a controlled rate or lower at a freely falling rate, a particular winch load.

It must be noted that the control in accordance with the invention provides a high degree of safety. In effect the freedom given to the motor or more generally to the receiver, to be freely moved under the action of an external force is subordinate to the exercise of a considerable force on the part of the operator at the lever 4 to overcome the force of the pressure on the slide valve 1a.

Of course the invention is not limited to the embodiment described and illustrated but on the contrary covers all variants and in particular all uses whatever may be the type of receiver under control.

Iclaim:

1. A fluid control system comprising a fluid motor, a first fluid line including first and second valves disposed in series, said first valve being movable selectively into open and close positions, said second valve being operable to selectively communicate said first fluid line with a source of fluid under pressure and a fluid discharge, a portion of said first fluid line connected only to said first valve being communicable with said source of fluid under pressure, and second and third fluid lines connected to said first fluid line and operatively connected to said fluid motor whereby said fluid motor is connected in parallel relative to said first valve.

2. A fluid control system according to claim 1 wherein said first valve normally is in the open position and said second valve normally communicates said first fluid line with said fluid discharge.

3. A fluid control system according to claim 1 wherein said first valve is urged into the closed position responsive to a predetermined pressure in said second fluid line.

4. A fluid control system according to claim 1 including actuating means operatively connected to said fiist and second valves.

5. A fluid control system according to claim 1 wherein said first valve consists of a slide valve having a movable spool, said spool being movable responsive to a predetermined pressure in said second fluid line to urge said first valve in the closed position.

6. A fluid control system according to claim 1 wherein said first and second valves consist of slide valves having movable spools provided with actuating rods, and including a control lever pivotally connected to the actuating rods of said first and second valves. I

7. A fluid control system according to claim 6 wherein said pivotal connections are spaced along the length of said control lever.

8. A fluid control system according to claim 1 including a one-way valve disposed in said first fluid line in series between said first valve and said fluid discharge.

9. A fluid control system according to claim 1 including a fourth fluid line interconnecting said first fluid line between said first valve and said source of fluid under pressure, and said fluid discharge, said fourth fluid line including a normally closed valve operable to open responsive to a predetermined pressure in said first fluid line between said first and second valves.

10. A fluid control system according to claim 1 including a one-way valve disposed in said first fluid line in series between said first valve and said source of fluid under pressure, and a fourth fluid line interconnecting said first fluid line between said first valve and said one-way valve, and said fluid discharge, said fourth fluid line including a normally closed valve operable to open responsive to a predetermined pressure in said first fluid line between said first and second valves.

1 1. A fluid control system according to claim 1 wherein said first and second valves consist of slide valves having movable spools provided with actuating rods, and including a control lever pivotally connected at spaced points along its length to said actuating rods, a one-way valve disposed in said first fluid line in series between said first valve and said source of fluid under pressure, and a fourth fluid line interconnecting said first fluid line between said first valve and said one-way valve, and said fluid discharge, said fourth fluid line including a normally closed valve operable to open responsive to a predetermined pressure in said first fluid line between said first and second valves.

12. A fluid control system according to claim 11 wherein said first valve is urged into the closed position responsive to a predetermined pressure in said second fluid line.

Claims

4. A fluid control system according to claim 1 including actuating means operatively connected to said first and second valves.

6. A fluid control system according to claim 1 wherein said first and second valves consist of slide valves having movable spools provided with actuating rods, and including a control lever pivotally connected to the actuating rods of said first and second valves.

11. A fluid control system according to claim 1 wherein said first and second valves consist of slide valves having movable spools provided with actuating rods, and including a control lever pivotally connected at spaced points along its length to said actuating rods, a one-way valve disposed in said first fluid line in series between said first valve and said source of fluid under pressure, and a fourth fluid line interconnecting said first fluid line between said first valve and said one-way valve, and said fluid discharge, said fourth fluid line including a normally closed valve operable to open responsive to a Predetermined pressure in said first fluid line between said first and second valves.