US3412350A - Ratchet relay with dual action pawls - Google Patents

Description

Nov. 19, 1968 c R 3,412,350

RATCHET RELAY WITH DUAL ACTION PAWLS 3 heets-Sheet 1 Filed April 11, 1966 WW Id;

new

ATTORNEYS Nov. 19, 1968 A. J. CARLI 3,412,350

RATCHET RELAY WITH DUAL ACTION PAWLS Filed April 11, 1966 5 Sheets-Sheet 2 INVENTOR ALVIN J. CARL] BY v M ATTORNEYS NOV. 19, 1968 3,412,350

RATCHET RELAY WITH DUAL ACTION PAWLS Filed April 11, 1966 5 Sheets-Sheet 3 FIG.3

J 7 94 LIE 95 93 2' 89 97 ll I2 ||r- 96 75 I L Q 86, 85 Ii 5? I I I 90 w 76 74 9 INVENTOR ALVIN J. CARLI I/Eq- ATTORNEYS} United States Patent 3,412,350 RATCHET RELAY WITH DUAL ACTION PAWLS Alvin J. Carli, Sebring, Ohio, assignor to Consolidated Electronics Industries Corp., a corporation of Delaware Filed Apr. 11, 1966, Ser. No. 541,653 18 Claims. (Cl. 335-123) ABSTRACT OF THE DISCLOSURE The disclosure shows a multiple contact electromagnetic relay wherein the armature moves an actuator plate in a rectilinear path. First and second pawls are pivoted on the actuator plate to cooperate alternatively with cylindrical pins on a ratchet wheel. During the attraction stroke of the armature the first pawl rotates the ratchet wheel through a first arc and during the retraction stroke of the armature the second pawl rotates the ratchet wheel through a second arc. A plurality of cams are rotated with the ratchet wheel and some contacts are actuated on the attraction stroke of the armature and others are actuated on the retraction storke of the armature.

The invention relates in general to a ratchet relay and more particularly to a multi-position relay actuated switch capable of having a variety of circuit conditions.

A four-position ratchet relay has been described in Patent 3,178,627 entitled, Electrical Control System for Motor Operated Doors, issued Apr. 13, 1965. The relay of the present invention may be used in a door operator control circuit, as one example of use.

In ratcheting relays involving a plurality of contacts and a plurality of circuit conditions it has been found that for reliable operation a fairly complex and expensive structure has been required. However, the complexity has detracted from the reliability simply because of the large number of parts and also the complexity has increased the labor and hence cost of assembly of the complete relay.

Accordingly an object of the invention is to provide an inexpensive, simple, rugged and reliable ratcheting relay.

Another object of the invention is to provide a relay with multiple conditions of plural contacts yet one which is extremely reliable in operation.

Another object of the invention is to provide a relay with a contact assembly which may be removed and replaced independently of the relay actuating coil and without requiring calibration of the contact positions.

Another object of the invention is to provide a relay with dual stroke capabilities to actuate a ratchet wheel on both the up and down strokes of the relay armature.

Another object of the invention is to provide a ratcheting relay with a simplified cam assembly which may be readily manufactured and assembled without error in assembly and without need to manually calibrate the position of the contact blades actuated by the cam assembly.

Another object of the invention is to provide a ratcheting relay having a given number of active positions of the contacts and moved into those positions by the combined advance and retract movements of the relay armature.

Another object of the invention is to provide a ratcheting relay with rounded ratchet teeth to provide a large bearing surface under all conditions of actuation of the ratchet wheel by a pawl.

Another object of the invention is to provide a ratcheting relay with an actuator plate carrying first and second pawls, both pawls being movable in the same direction 3,412,350 Patented Nov. 19, 1968 for advancing movement of the armature and operative to partially rotate the ratchet wheel, and both pawls being movable in the opposite direction during retract of the armature to again advance the ratchet wheel in the same direction.

The invention may be incorporated in a ratcheting relay, comprising, in combination, a relay coil, an armature movable upon energization of said coil, a rotatable cam assembly, rotatable ratchet wheel means having teeth and connected to rotate said rotatable cam assembly, pawl means cooperable with said teeth of said ratchet wheel means, means connecting said armature to relatively move said ratchet wheel means and-said pawl means upon movement of said armature, energization of said relay coil moving said armature in a first direction and causing said pawl means to rotate said ratchet wheel means and said cam assembly through a first given arc, deenergization of said relay coil moving said armature in a second direction to rotate said ratchet wheel means and said cam assembly through a second given arc, a contact assembly, first and second pairs of contacts in said contact assembly, rotation of said cam assembly through said first given are positioning said cam assembly for actuation of said first pair of contacts and rotation of said cam assembly through said second given are positioning said cam assembly for actuation of said second pair of contacts.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a elevational View, partly in section of a relay incorporating the invention;

FIGURE 2 is a top view of the relay;

FIGURE 3 is a sectional view on line 33 of FIGURE FIGURE 4 is a sectional View on line 44 of FIGURE FIGURES 5, 6, 7, and 8 are sectional views on the similarly numbered lines on FIGURE 1; and,

FIGURE 9 is a schematic diagram of a motor control circuit with which the relay may be used.

The figures of the drawings show a ratcheting relay 11 which is the preferred embodiment of the invention. This relay may be used in many different circuit arrangements and FIGURE 9 shows one possible use in a door operator control circuit 12. This is almost the same control circuit as shown in Patent 3,178,627 wherein a four-position relay was used to control a motor to open and close a garage door. The relay 11 includes a housing 14 made of identical halves 15 and 16. A relay coil 17 is mounted in the lower end of the housing 14 and includes a permeable frame 18 and a pole piece 19. A movable armature 20 is pivoted to the frame 18 and a leaf spring 21 urges the armature 20 away from pole piece 19. A mounting screw 22 may extend into a threaded aperture in the frame 18 to fasten the entire relay 11 to a support 23.

A rotatable cam assembly 26 is fixed on an axle 27 journalled in the two halves of the housing 14. This cam assembly has an axis 28. An actuator plate or support 29 forms a link between the armature 20 and the cam assembly 26 for rotation thereof. This actuator plate 29 moves in a path perpendicular to the axis 28. The cam assembly 26 includes a ratchet wheel 30 having a plurality of teeth 31. These teeth are in the form of cylindrical pins extending on axes parallel to the axis 28 from a planar face 32 of the ratchet wheel 30.

The actuator plate 29 has an aperture 35 receiving a tongue 36 on the end of the armature 20. This links the armature to the actuator plate 29 to move this plate. First and second pawl arms 37 and 38 are pivoted on the actuator plate 29 by pivot pins 39. A coil tension spring 40 urges the arms together and toward engagement with the ratchet wheel teeth or pins 31. The first pawl 37 is provided with a pull notch 41 and the second pawl 33 is provided with a push notch 42. These notches engage generally diametrically opposed portions of the ratchet wheel 30. In this preferred embodiment there are eight of these pins 31 with eight positions on the cam assembly 26. Four positions make up a complete cycle and hence one revolution of the cam assembly completes two complete cycles of the circuit 12. The actuator plate 29 has a tongue 43 extending through a contact plate assembly 44 which closes the end of the housing 14 opposite the relay coil 17. A coil compression spring 45 is held on the tongue 43 by a retainer 46 and urges the actuator plate 29 upwardly as viewed in FIGURE 1 and hence urges the armature 20 away from the pole piece 19. A stop lug 47 on the actuator plate 29 engages one of the ratchet teeth 31 to limit the down stroke of the actuator plate 29 and a stop lug 48 engages another pin 31 to limit the up stroke of plate 29.

The cam assembly 26 includes first and second cam parts 51 and 52, respectively. The first cam part includes first and second rotary cams 53 and 54, respectively. The second cam part 52 includes third and fourth rotary earns 55 and 56, respectively, and the ratchet wheel 30. The first and second cam parts 51 and 52 are fixed on the axle 27 for positive rotation of the entire cam assembly upon rotation of the ratchet wheel 30. The first and second cam parts 51 and 52 are suitably made from some insulation material such as nylon or Delrin which are easily molded and having smooth, low-friction surfaces. The first cam part includes both the first and second rotary cams 53 and 54 as shown in FIGURES 1, 5, and 6. These two rotary cams 53 and 54 may be made in a simple two-part mold separable on the junction line between the rotary earns 53 and 54. The second cam part 52 may also be made in a simple two-part mold separable on a parting line between the ratchet wheel 30 and the fourth rotary cam 56. This is possible because the fourth rotary cam 56 has no undercuts relative to the third rotary cam 55 and hence the parting line may be at the face of the ratchet wheel 30 which is contiguous to the fourth rotary cam 56. This permits the cam assembly 26 to be made from only two parts for quick and easy assembly and assurance of proper actuation of the contact plate assembly. The two cam parts 51 and 52 may be forced onto a splined portion of the axle 27 in order to assure positive rotation of the parts of this cam assembly 26.

The contact plate assembly 44 includes an insulator plate 59 which closes the open end of housing 14. This insulator plate 59 has tabs 60 extending through apertures in the side wall of housing half 15. Spring clips 61 plus the tabs 60 retain this insulator plate 59 on the housing 14. A plurality of pairs of contact strips may be mounted on the insulator plate 59. FIGURE 2 best shows that in this preferred embodiment four fixed contact strips are provided, numbers 62 to 65 respectively, and four movable contact strips are provided, number 66 to 69 respectively. Cooperating contacts are provided on the outer ends of each respective pair of contact strips as illustrated in FIGURE 3. Each of the movable contact strips 66-69 includes a U-shaped carn follower 70 on the inner end for cooperation with the respective rotary cam of the cam assembly 26.

With the eight ratchet teeth or pins 31 provided, eight positions of the relay switch 11 may be accommodated. In the preferred embodiment only four switch conditions are needed and accordingly two complete cycles of switch conditions are provided for each full revolution of the cam assembly 26.

FIGURE 9 shows a door operator control circuit 12 With which this relay 11 may be used. The circuit 12 includes a motor 74 having a stator winding 75 energized directly for the upward movement of a garage door and having another stator winding 76 energized directly for the reverse rotation of the motor to cause downward movement of the garage door. The contact plate assembly 44 includes pairs of contacts 81, 82, 83 and 84 on the first through fourth contact strips respectively. These pairs of contacts are illustrated in the circuit diagram of FIG- URE 9. The circuit is energized from a suitable voltage source 85 such as 115 volts AC. 60 cycle with energization to the motor including a conductor 86 to one end of both stator windings 75 and 76. A conductor 87 leads to a radio connector plug 88 for energization of a radio receiver which may also receive signals to control operation of the control circuit 12. A conductor 89 connects to conductor 87 and supplies source voltage to the stator windings 75 and '76 through the relay contacts 82 and 83, respectively. Relay contacts 84 control a lamp 90 for illumination of the garage. Relay contacts 81 control application of low voltage power such as 24 volts from a transformer secondary 91 to the relay coil 17. One end of the secondary 91 may be grounded at 92 and relay contacts 81 are connected to ground through a conductor 93 and several switches in parallel. These switches include an up limit switch 94, a down limit switch and a torque switch 96. A push button switch 97 is also connected to ground to energize the relay coil 17.

Operation When the relay coil 17 is energized, the armature 20 will be attracted toward the pole piece 19. This moves the actuator plate 29 downwardly, as viewed in FIGURE 1. The first pawl 37 has the pull notch 41 in engagement with one of the pins 31. The downward movement of actuator plate 29 thus pulls on the engaged pin 31 to rotate the cam assembly 26 about 22%; degrees in a clockwise direction as viewed in FIGURE 4. The stop lug 47 engaging one of the pins 31 limits this first arcuate motion of the cam assembly 26. During this downward movement of actuator plate 29, the second pawl 38 also moves downwardly because it is also pivoted on plate 29. The push notch 42 has thus moved into engagement with the next adjacent pin 31. Upon deenergization of the relay coil 17, the springs 21 and 45 effect retractile movement of the armature 20 away from pole piece 19 and this moves the actuator plate 29 upwardly as viewed in FIGURE 1. During this upward movement, the pawl 38, by means of the push notch 42, rotates the ratchet wheel 30 approximately another 22% degrees for a total of 45 degrees arcuate movement for one energization and deenergization of the relay coil 17. A second arcuate motion of the cam assembly 27 is limited by the stop lug 48 engaging one of the lower ratchet teeth or ratchet pins 31. The push button switch 97 is connected from one end of relay coil 17 to ground 92. When this push button switch 97 is actuated, the relay coil 17 will be energized. This moves the cam assembly 26 about 22 degrees, as described above. This closes contacts 83 and 84 to turn on the lamp 90 and also to start the motor 74 running to open the door. When the push button 97 is released the relay coil 17 will be deenergized. This moves actuator plate 29 downwardly rotating cam assembly 26 about another 22 degrees clockwise. This closes contacts 81 and maintains contacts 83 and 84 closed. Closing of contacts 81 does not change the circuit condition, it merely places into the circuit the switches 94, 95, and 96 to control energization to relay coil 17. The torque switch 96 may be like a centrifugal switch driven from the output of the motor 74 to be closed when the motor is at rest and to be opened when the motor is up to speed. The limit switches 94 and 95 may be actuated at the ends of travel of the door moved by the motor 74.

When the door has reached the end of its upward travel to an open position, the up limit switch 94 will be actuated. This energizes relay coil 17 moving actuator plate 29 downwardly to rotate the cam assembly 26 approximately another 22 degrees. The open contacts 81 and 83 and contacts 84 are maintained closed to maintain the lamp 90 illuminated. With contacts 83 open, the motor 74 is deenergized. The opening of contacts 81 relieves the grounding condition on the relay coil 17 and thus it is deenergized permitting actuator plate 29 to move upwardly rotating cam assembly 26 another approximately 22 degrees. This does not change the condition of the contacts 8184.

Upon the push switch 97 again being actuated the relay coil 17 is energized to move the armature and actuator plate 29 downwardly. This again rotates the cam assembly 26 approximately 22 /2 degrees clockwise. This closes contacts 82 and maintains contacts 84 closed. This conditions the motor 74 for a reverse direction of movement to close the door, and the motor starts to run. When the pus-h button switch 97 is released, the relay coil 17 is deenergized and the actuator plate 29 moves upwardly to move the cam assembly 26 another approximately 22 /2 degrees clockwise. Such movement closes contacts 81 and maintains contacts 82 and 84 closed. Thus the motor continues to run in reverse and the lamp 90 is energized and also the closing of contacts 81 means that switches 94, 95 and 96 are now available to control energizati-on or relay coil 17. When the motor reaches its down limit, either the down limit switch 95 is actuated or the torque switch 96 is closed by stalling of the motor 74 and this energizes the relay coil 17. This pulls actuator plate 29 down to open the contacts 81 and 82, yet contacts 84 remain closed. Opening of contacts 82 deenergizes the motor 74 and opening of the contacts 81 removes the energizati-on for relay coil 17, hence it is deenergized. Upon deenergization of this relay coil 17, the actuator plate 29 moves upwardly to rotate cam assembly 26 another approximately 22%. degrees, and this opens contacts 84. Thus the complete cycle of openation of the door operator control circuit 12 has been achieved by one-half revolution of the cam assembly 26.

It will be noted at the beginning of the cycle contacts 83 and 84 are closed upon the advance movement of the armature 20 whereas contacts 81 do not close until the retractile movement of this armature 20 and contacts 83 and 84 remain closed. This has a very definite advantage in the relay 11. In the prior Patent 3,178,627 it was necessary to have separate switch 60 actuated by the condition of the relay armature in order to control the circuit effectiveness of the up and down limit switches and the torque switch. In the present relay construction the necessity for this series switch 60 is eliminated. In many garage door operators such as on commercial garages and other such establishments, it is necessary to hold the push-button switch depressed in order to make the door move in an up or down direction. Accordingly some people, not familiar with the proper operation of a household garage door operator, may hold the push button switch 97 depressed during the entire door movement in an up or down moving direction. This was the reason for providing the switch controlled by the armature position in the Patent 3,178,627, because it prevented the control system from getting out of synchronization with the door openator. If the contacts 81 in the present invention were to close immediately upon armature advance movement, along with closure of contacts 83 and 84, then the motor 74 would start to run to move the door. However if the push button switch 97 were held depressed for the entire door opening movement, then this would keep the relay coil 17 energized and when the limit switch 94 was actuated it would not be able to again energize the relay 17 to again ratchet the cam assembly 26 to the next position whereat the motor wouldnbe deenergized. The person would observe that the door had completely closed or completely opened and then would release the push button switch 97, however the relay coil 17 would remain energized, because of the now closed limit switch 94, 95 or torque switch 96. If this were a door closed condition, and

the person left the garage, then the relay coil 17 could be retained energized and burn out this relay, especially after several hours of energization.

In the present invention this lack of synchronization of the relay position and the door operator condition is eliminated. When the person observes that the door has opened or closed and has removed his finger from the push button 97, this will deenergize the relay coil 17 and close relay contacts 81. With a closed door condition and either the limit switches 94 or closed and also the torque switch 96 closed, this will again energize the relay coil 17 to ratchet the cam assembly 26 to the next condition whereat the motor 74 will be deenergized and also the relay coil 17 will be deenergized. Thus by having the relay contacts 81 not closed until after the armature retractile movement has completed, the present invention of a relay eliminates the need for the series switch 60 of Patent 3,178,627 and also prevents the door operator from getting out of synchronization with the relay 11.

The contact plate assembly 44 may easily be removed by removing the spring clips 61, the retainer 46 and spring 45 and then the contact plate assembly 44 may easily be slipped from the end of the housing 14. Because the housing 14 may be made from two molded halves of insulating material, the dimension between the end of the housing upon which the contact assembly 44 seats and the journals for the axle 27 may be precisely controlled. Also the insulator plate 59 may be made from insulation material in a simple two-part mold and the dimensions thereof may be controlled quite accurately. Accordingly it is possible to assemble tall the contact strips on the insulator plate 59 and then to mount this contact plate assembly 44 on the end of the housing 14 for actuation by the rotatable cam assembly 26 without any calibration or adjustment of the contact strips 6269. In the usual relay construction it is necessary, after assembly of the complete relay, to bend the contact strips to adjust the position thereof to be properly actuated upon movement of the armature of the relay. In this relay 11 the position of these contact strips and hence the contacts is carefully controlled during manufacture so that any one contact plate assembly 44 will fit on the housing 14 without the necessity of adjusting the positions of the contacts. This saves considerably in assembly time and thus lowers the cost of the relay.

It will be noted that both pawls 37 and 38 move in the same direction upon advance movement of the armature 20 and both pawls 37 and 38 again move in the same opposing direction upon retractile movement of the armature 20. First the pawl 37 pulls the cam assembly through a first given are and second the pawl 38 pushes the cam assembly 26 through a second given arc. In this preferred embodiment each of the two arcs are preferably the same and about 22 /2 degrees for a total 45 degree rotation for advance and retract of the armature 20. Because the pawls 37 and 38 act on generally diametrically opposed portions of the ratchet wheel 36 and because they 'act alternatively, no locking pawl is necessary as is usually found in ratchet wheel mechanisms. Such normal locking pawl is one which prevents reverse rotation of the ratchet wheel during the retract stroke of the pawl normally causing arcurate movement. This is another simplification in the relay 11 by elimination of such locking pawl.

The ratchet teeth 31 being cylindrical pins provides a large cylindrical bearing surface between the notches 41 and 42 and the teeth or pins 31. In the normal ratchet wheel mechanism there is only a line contact between the pawl and the tooth of the ratchet wheel and thus this can cause rapid wear on the pawl and on the ratchet teeth. With this large cylindrical bearing surface of the present invention, such rapid wearing is eliminated and also the cylindrical bearing surface is maintained even during rotation of the cam assembly 26, which changes 7 the attitude of the cam assembly 26 relative to the pawls 37 and 38.

The present disclosure includes that contained in the appended claims, as well as that of the foregoing description.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. A ratcheting relay, comprising, in combination, a relay coil, an armature movable upon energizing of said coil, a rotatable cam assembly means,

rotatable ratchet wheel means having teeth and connected to rotate said rotatable cam assembly, pawl means cooperable with said teeth of said ratchet wheel means, means connecting said armature to relatively move said ratchet wheel means and said pawl means upon movement of said armature,

energization of said relay coil moving said armature in a first direction and causing said pawl means to rotate said ratchet wheel means and said cam assembly through a first given arc,

deenergization of said relay coil moving said armature in a second direction causing said pawl means to rotate said ratchet wheel means and said cam assembly through a second given are,

a contact assembly,

first and second pairs of contacts in said contact assembly,

means establishing actuation of said first pair of contacts upon rotation of said cam assembly means through said first given arc,

and means establishing actuation of said second pair of contacts upon rotation of said cam assembly means through said second given arc.

2. A ratcheting relay as defined in claim 1 wherein said pawl means includes first and second pawls, said first pawl positively rotating said cam assembly in a given rotational direction for the first direction of movement of said armature and said second pawl positively rotating said cam assembly in said given rotational direction for the second direction of movement of said armature to have said rotatable cam assembly always under positive rotation and to thereby preclude reverse rotational direction of said rotary cam assembly without need for any locking pawl.

3. A relay as defined in claim 1 wherein said pawl means includes two pawls mounted on a common actuator to move both pawls in one direction upon said armature moving in said first direction and to move both pawls in the opposite direction upon said armature moving in said second direction.

4. A relay as defined in claim 1 wherein said pawl means includes two pawls which cooperate with generally diametrically opposed portions of said ratchet wheel means.

5. A relay as defined in claim 1 including a planar surface on said rachet wheel means perpendicular to the axis of rotation thereof,

a plurality of cylindrical pins extending from said planar surface parallel to said axis,

, and arcuate engagement surfaces on said pawl means to engage the cylindrical surfaces of said pins as the teeth of said ratchet wheel for an arcuate bearing surface between said pins and pawl means despite changing attitudes therebetween throughout said first given are.

6. A relay as defined in claim 1 including a frame,

means to journal said cam assembly on said frame,

means to fix said ratchet wheel means to said cam assembly for mutual rotation, and means to move said pawl means upon movement of said armature to rotate said ratchet wheel means. 7. A relay as defined in claim 1 wherein said firs-t and second given arcs are approximately equal,

rotation of said cam assembly through said first given arc actuating said first pair of contacts and rotation of said cam assembly through said second given are actuating said second pair of contacts. 8. A relay as defined in claim 1 wherein said rotatable ratchet wheel means is a single ratchet wheel,

means causing said pawl means to act on one side of said ratchet wheel during movement of said armatrue and in said first direction, and means causing said pawl means to act on the generally opposite side of said ratchet wheel during movement of said armature in said second direction for unidirectional movement of said ratchet Wheel and cam assembly without need for a locking pawl. 9. A relay as defined in claim 1 including said first pair of contacts being actuated closed upon movement of said armature in said first direction and wherein said second pair of contacts are actuated closed and said first pair of contacts are maintained closed upon movement of said armature in said second direction.

10. A relay as defined in claim 1 including first and second rotary cams on said cam assembly,

said first and second rotary cams being formed from insulation material and being moldable in a two-part mold separable on a parting line at the junction of said first and second rotary cams. 11. A relay as defined in claim 1 including first and second rotary cams on said assembly,

said first rotary cam being adjacent said ratchet wheel means, said first and second rotary cams and said ratchet wheel means being of insulation material with said first rotary cam contiguous to said ratchet wheel means and having no undercuts relative to said second rotary cam in order to permit manufacture in a twopart mold separable on a parting line between said ratchet wheel means and said first rotary cam. 12. A ratcheting or stepping relay, comprising, in combination, a relay coil.

an armature movable in an advancing stroke upon energization of said coil, said armature being movable in a retracting stroke upon deenergization of said coil, rotatable ratchet wheel means, pawl means cooperable with said ratchet wheel means, contact means, means acting through said ratchet wheel and pawl means effective upon completion of said advancing stroke of said armature to establish said contact means in a first condition, and means acting through said ratchet wheel and pawl means effective upon completion of said reaction stroke of said armature to establish said contact means in a second condition. 13. A relay as defined in claim 12, including cam means actuated by said ratchet wheel means and pawl means,

said cam means establishing said first and second conditions of said contact means upon said advancing and retracting strokes of said armature. 14. A ratcheting relay, comprising, in combination, a frame,

a relay coil mounted on said frame, a movable armature cooperating with said coil, a rotatable cam assembly journalled on an axis on said frame, a rotatable ratchet wheel having teeth and connected to rotate said rotatable cam assembly, first and second pawls each moved by said armature and cooperable with said wheel,

energization of said relay coil moving said armature toward said pole piece of said relay coil and causing said first pawl to move in a first direction to rotate said ratchet wheel and said cam a first given arc,

said second pawl also moving in said first direction to engage the next adjacent tooth to that formerly engaged,

deenergization of said relay coil effecting retractile movement of said armature away from said pole piece to move said pawls in a second opposing direction and causing said second pawl to rotate said ratchet wheel a second given are,

a contact plate assembly having an insulator plate mounted on said frame,

a first pair of contacts on said insulator plate being actuated upon movement of said first pawl in said first direction and a second pair of contacts on said insulator plate being actuated upon movement of said second pawl in said second direction.

15. A relay as defined in claim 14 including an actuator plate slidable on a path in said frame,

means pivoting said first and second pawls on said actuator plate to cooperate with said ratchet wheel,

said actuator plate slidable in a rectilinear path generally perpendicular to the axis of said cam assembly.

16. A relay as defined in claim 14 including an actuator plate moveable by said armature,

means movably mounting each of said first and second pawls on said actuator plate,

said first and second pawls extending in the same general direction and cooperating with generally diametrically opposed portions of said ratchet wheel,

and a pull notch on said first pawl and a push notch on said second pawl for cooperation with said ratchet teeth on opposite strokes of said actuator plate.

17. A ratcheting relay, comprising, in combination, an

enclosing housing,

a relay coil and a pole piece mounted in one end of said housing,

a pivoted armature cooperating with said pole piece,

an actuator plate slidable on a path in said housing and connected to said armature to be slidably moved thereby,

first and second pawl arms pivotedly carried on said actuator plate,

a spring urging said arms toward each other,

a rotatable cam assembly journalled on an axis in said housing perpendicular to said path,

a rotatable ratchet wheel fixed to said cam assembly,

eight pins symmetrically disposed on a circle on said ratchet wheel having the center thereof on said axis,

a pull notch and a push notch on said first and second arms, respectively,

said spring causing said notches to engage pins generally diametrically opposed on said ratchet wheel,

energization of said relay coil moving said armature into close engagement with said pole piece of said relay coil and sliding said actuator plate in a first direction on said path to have said pull notch on said first arm rotate said ratchet wheel and said can] approximately 22% degrees,

said second arm also sliding in said first direction to 10 have said push notch engage the next adjacent pin to that formerly engaged,

deenergization of said relay coil effecting retractile movement of said armature away from said pole piece to slide said actuator plate in a second opposing direction on said path to cause said push notch on said second arm to rotate said ratchet wheel approximately another 22% degrees,

said cam assembly including first and second parts of insulation material,

first and second rotary cams on said first cam part,

third and fourth rotary cams and said ratchet wheel on said second cam part,

said first cam part and said second cam part being assembled on a shaft together to form said cam assembly,

said first cam part being molded in a two-part mold separable on a parting line at the junction between said first and second rotary cams,

said fourth rotary cam on said second cam part being contiguous to said rotary ratchet wheel and having no undercuts relative to said third rotary came in order to permit manufacture in a two-part mold separable on a parting line between said rotatable ratchet wheel and said fourth cam,

a contact plate assembly having an insulator plate mounted on and closing the end of said housing opposite the end containing said relay coil,

said contact plate assembly including four movable contact strips on said insulator plate and each having cam followers for cooperation with a different one of said rotary cams,

four fixed contact strips on said insulator plate and each carrying a fixed contact for cooperation with a movable contact on a respective one of said movable contact strips,

and one of said pairs of contacts being actuated upon movement of said actuator plate in said first direction and another of said pairs of contacts being actuated upon movement of said actuator plate in said second direction.

18. A relay as defined in claim 12, including a support,

said pawl means including first and second pawls carried on said support,

and means guiding said support for rectilinear movement so that each of said first and second pawls cooperates substantially equally with said ratchet wheel means.

References Cited UNITED STATES PATENTS 652,151 6/1900 Tirrill 335-140 2,428,569 10/1947 Hunt et a1 335-440 3,207,873 9/1965 Slonneger 335123 FOREIGN PATENTS 1,281,149 11/1961 France.

BERNARD A. GILHEANY, Primary Examiner.

H. BROOME, Assistant Examiner.

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