US2500956A

US2500956A - Time-delay relay

Info

Publication number: US2500956A
Application number: US588426A
Authority: US
Inventors: Clarence L Mershon
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1945-04-16
Filing date: 1945-04-16
Publication date: 1950-03-21
Anticipated expiration: 1967-03-21

Description

March 21, 1950 c. L. ,MERsHoN 2,500,956

TIME DELAY RELAY Filed April' 16, 1945 5 -F- ---AllllllMmmj-l` WITNESSESE INVENTOR C/df/ce .Many/70N.

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Patented Mu. 2i, 195o TIME-DELAY RELAY Clarence L. Mershon, Lima, O hio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 16, 1945, Serial No. 588,426

(Cl. 175-3Z0) 10 Claims.

My invention relates, generally, to relays and more particularly, to a time delay relay device suitable for use in electrical control systems of various kinds, such as on aircraft and the like, where a light weight, compact, and rugged device is required.

Heretolore. many time delay relays of various kinds have been proposed, but such devices are usually too large. heavy, and complicated, and have too great a variance in time delay with ambient temperature changes to permit of their use where a simple, compact, accurate, and light weight device is required. l

Furthermore, maxrv of these prior art devices do not embody such features as readily adjustable timing periods. a multiplicity of control contacts, electrical timing adjustment instead of mechanical, instantaneous automatic reset from any point in the timing cycle or period; operate on direct current, withstand excessive vibration, and function to provide the desired timing period upon being deenergized.

Accordingly, it is an object ofmy invention,

generally stated, to provide a time delay relay device which shall be of simple, compact, light weight, and rugged construction, and which shall function to provide any desired timing period within its range of operation under such adverse operating conditions as wide changes in ambient temperature and excessive vibration.

' .A more speciilc object of my invention, is to provide a time delay relay device of the character described wherein the timing adjustment may be effected electrically instead of mechanically and which may be readily varied by a simple adjustmentover the operating range of the device. Another object of my invention is to provide a device oi' the character described wherein the timing operation or function is eilected in respouse to the deenergization instead of the energiaation of the device. Another object of my invention is to provid a device of the character described wherein the timing operation is controlled by varying the speed of a direct-current motor which is nor.- maliy deenersiedand. becomes energized in response to the initiation of the timing operation. A still further object of my invention is to provide a device of the characterdescribed wherein a control relay element having one or more contact members` is controlled by a cam-actuated switch operated by an electric motor connected in driving relation therewith through an electromagnetically operated clutch element which is so controlled as to engage the clutch and start the driving motor in response to the deenergization thereof.

Another object of my invention is to provide a device of the character described wherein all of the electrical and mechanical parts thereof except the control relay element are mounted on the motor or gear motor shaft to provide a compact unitary device.

Another object of my invention is to provide a device of the character described wherein the timing period is adjusted by controlling the speed of the motor by means of a variable resistance device in the form of a variable resistor or potentiometer connected in the motor circuit.

These and other objects of my invention will become more apparent from the following detailed description of a preferred embodiment thereof when read in conjunction with the drawing, in which:

Figure l isa diagrammatic view of a time delay relay device embodying the principal features of my invention;

Fig. 2 is a diagrammatic view of a portion of the device of Fig. 1 showing a modification of the speed control for the motor; and

Fig. 3 is a similar view showing a further modification of the speed control.

In practicing my invention in one form thereof, a control relay element is electrically controlled by a normally closed cam-actuated switch,

the cam element of which is driven by a directactuated clutch element, and the energization of the motor controlled by a switch actuated in accordance with the engagement and disengage-y ment of the clutch. The energizing circuitv of the clutch solenoid is controlled externally by control contacts on the device utilized to initiate the timing operation. When the solenoid is energized, the clutch is disengaged, the cam is in a retracted or yreset position. and the motor is deenergized. When the solenoid is deenergizedy, the motor is energized through the closure of its control switch mechanically actuated in re-L spouse to the release of the clutch' to its engaged 3 position, and a timing period or cycle is'initiated. At the end thereof the control relay element is actuated which, in addition to controlling external circuits, also deenergizes the motor. When the solenoid is reenergized, the clutch is disengaged and the cam element of the cam-actuated switch returned to its reset position. The speed of the motor which determines the timing period is controlled by either a variable rheostat or potentiometer in its armature circuit or a` potentiometer connected in both its amature and field circuits.

Referring now to Fig. 1 of the drawing, the numeral I designates, generally, a time delay relay device constructed in accordance with the principles of my invention and embodying one form of the speed control for the motor.

This device, in general, embodies Ya control relay element II, a cam-actuated switch I2, an electromagnetically actuated clutch I3, and a driving motor I4. The control relay element II is provided with an operating winding I5, a plurality of control contact members I6 for use in external circuits, and a normally open contact member I1 connected in the holding circuit for this relay element.

The control relay element I I may be energized from any suitable source of current such as a. battery I8, which also may be used to energize the driving motor I4 and other electrical elements of the device.

In this embodiment of the invention, provision is made for normally retaining the control relay element II in an energized condition and for deenergizing and releasing it at the end Aof the timing period or cycle as provided by the other elements of the device.

Accordingly, the energizing circuit for the control relay element I I includes the normally closed contact'members I9 of the cam-actuated switch I2 and also the normally open contact members 2I of a control switch 22, the purpose of which will be described hereinafter. The holding circuit for the control relay device II includes its normally open contact member I1 connected in shunt relation to the contact members 2| of control switch 22, as shown.

As shown in the drawing, the device is in a deenergized condition, and, therefore, the control relay element II is open or deenergized, the clutch I3 is engaged, and the contact members 2l are in their normally open position. It will be noted that the cam element 23 is in a reset or retracted position which is its normal non-operating position, as determined by the functioning of the reset spring 24 and the adjustable stop 20.

The clutch device I3 comprises a clutch element 25 having one portion 26 thereof mounted upon the end of shaft 21 which carries the cam 23, and the other portion 28 thereof mounted upon the end of shaft 29 which is connected to the motor I4 through suitable gears 3l.

The clutch device I3 also includes a solenoid comprising an armature member 32 and a winding 33. The armature 32 is connected to the movable element 28 of the clutch, and both are slidably mounted upon shaft 29. A The solenoid Winding 33 is mounted within a casing 34 which is stationarily mounted, and in which4 are both slidably and rotatably mounted the armature 32 and a flanged member 35 carried by the shaft 29.

The end of the armature which is connected to the movable portion 28 of the clutch is provided with a longitudinal slot 33 through which a pin 31 extends. This pin is attachedto the shaft 29 and functions to connect this shaft in driving relation with the movable element 28 of the clutch and permits the armature 22 to move longitudinally upon the shaft 23 to effect the engagement and disengagement of the clutch.

It will be readily understood that when the solenoid winding 33 is energized such as by closing the switch 38, the amature 32 will be actuated to the left, as viewed in the drawing. to disengage or open the clutch.

The switch 38 may be representative o! the contact members of any switch device or relay actuated in accordance with some external oondition in response to the occurrence of which it is desired to initiate the operation of the time delay relay device to effect a timing operation through the operation of the control relay element II.

In order to limit the movement of the armature 32 toward the left, as viewed in the drawing, a pair of cup-shaped washers 4I and 42 are mounted in facing relation upon the enlarged portion 39 of the shaft 29, which is provided with a shoulder at 43 and a coil spring 40 disposed between these washers upon the shaft. This arrangement provides for normally biasing the clutch to its engaged position when the solenoid winding 33 is deenergized and permits movement of the armature 32 and the flanged member 35 to the left in response to the energization of the solenoid winding.

In this embodiment of the invention, the timing period or cycle is provided by effecting the engagement of the clutch and at the saine time effecting the energization of the driving motor I4. Thus, it is apparent that the driving motor must be maintained in a deenergized condition until the timing operation is initiated, and it is a function of the control switch 22, previously referred to, to control the energization of the motor. This switch 22 is arranged to be actuated to one or the other of its two operating positions in accordance with the movement of the clutch element 28.

In addition to the normally open contact members 2|, the control switch 22 is provided with normally closed contact members 44. The actuating arm 45 of this switch is pivotally mounted at 46, and its upper end 41 is biased into engagement with the flanged member 35 by a spring 48. It will be readily understood that by means of this arrangement the movement of the armature 32 to the left, as viewed in the drawing, effects the closure of contact members 2| and the opening of contact members 44. The switch is maintained in either one of its two operating positions regardless of the rotation of shaft 29 because of the sliding engagement between the flanged member 35 and the upper end 41 of the actuating arm 45.

In this embodiment of the invention, the motor I4 is disposed to be energized from the battery I8 through the contact members 44 of control switch 22 and the normally open Contact members II of the control relay element Il.

In order to provide for adjusting the timing period or cycle of the relay device, provision is made for controlling the speed of the driving motor I4. In this instance, a variable resistor 5I connected in the armature circuit of the motor I4 is utilized. It will be readily understood that by adjusting the movable contact element 52 of this resistor, the armature current and thus the speed of the driving motor may be varied at will over the operating range of the device. As shown in Fig. 1, the motor Il is a direct-current motor having a self-excited shunt field winding Ila.

An additional adjustment of the timing period may be made by adjusting the stop 20, if desired, which determines the length of travel of the cam.

In the operation of this device. it may be assumed that the control switch 38 is closed which energizes the solenoid winding 33 from the battery I3 over an obvious energizing circuit.

Upon energization of the solenoid winding 33, the amature 32 is moved to the left to open the clutch and at the same time actuate the control switch 22 so as to cause its contact members M to open and contact members 2| to close. The closure of contact members 2| completes an energizing circuit for the control relay element which extends from one terminal of the battery Il through conductors 53 and 5I, contact members 2|, conductor 55, contact members I9, con- ,ductor 56, operating winding |5, and conductor l1 to the other terminal of the battery.

Upon the closure of control relay element its contact members I1 are closed to establish a holding circuit in shunt relation to Icontact members 2| of the control switch 22 so that this switch may be actuated to its other positijon without deenergizing the control relay element.

Upon the occurrence of an external condition such as to call for a timing operation, the solenoid winding 33 is deenergized by the opening of switch 33. When this occurs, the clutch becomes engaged as the result of the force exerted by the biasing spring 40 and the movement of the flanged member 35 to the right actuates the control switch 22 to its other position where its contact members M are closed, as shown.

With the clutch now engaged, the motor I4 becomes energized through a circuit extending from one terminal of the battery through conductors 8| and 62, the motor armature, the variable resistor conductor 63, contact members Il, conductors 55 and B4, contact members |1, and conductor 53 to the other side of the battery.

The motor now drives the cam 23 through a partial revolutionl at which time contact members I9 are opened. The opening of these contact members interrupts the energizing circuit of the control relay element and it moves to its deenergized position to effect the desired control operations controlled through its contact members I6.

The opening of contact members |1 of the control relay element interrupts the energizing circuit of the motor I4 to stop the movement of the cam 23. At this time, the clutch is still engaged, and the cam 23 remains in the position in which it was stopped so that contact members I3 remain open. As soon as the switch 38 is closed to reenergize the solenoid winding 33, the clutch is again actuated to its disengaged position, and when this occurs, the spring 2l resets the cam 23 to its original starting position. It will be apparent that this resetting operation occurs very quickly in response to the disengagement oi' the clutch. This completes the cycle of operation of the time delay relay device, and it is now in condition to function in the same manner in response to a subsequent opening of switch 38.

Referring now to Fig. 2 of the drawing, there is shown a modification of the control for the motor I4 wherein a potentiometer 1| is used instead oi the variable resistor 5| -as in Fig. 1. In this instance, 'when contact members 44 of the 6 co'ntrol switch 22 are closed, the potentiometer is connected across the battery I3. 0ne terminal lof the armature of the motor Il is connected directly to one side of the battery through conductor 62, and the other terminal of the armature is variably connected to the potentiometer 1|. v It will be apparent that by means of this arrangement, the speed of the motor I4 may be adjusted to control the timing period-,or cycle of the relay device in exactly the same manner as in the system of Fig. 1.

In Fig. 3, there is shown a further modification of the motor control system wherein one terminal of the motor is variably connected to a potentiometer `12 in the same manner as in Fig. 2, and the shunt ileld winding lla. is also variably connected to the potentiometer 12. By means of this arrangement, the voltage to which the field winding Ila is subjected may be varied as well as the armature voltage.

Referring again to Fig. 1, it will be apparent that all of the operating elements of the device except. the control relay element I| may be mounted upon the motor shaft or, as shown, upon the shaft of the gearing 3|. While the motor Il and gearing 3| have =been shown separately, it

is to be understood that they may be combined in the form of a gear motor having a main drive shaft represented by the shaft 29 upon which the solenoid winding 33, armature 32, clutch element 25, cam 23, and other elements ofthe device may be mounted so as to form a unitary structure of a compact and light weight nature.

In view of. the foregoing description, it will be apparent that my invention provides a time delay relay device which is of simple and light weight construction suitable for controlling a multiplicity of circuits and which has a readily adjustable timing period or cycle. In addition, the relay device of my invention automatically functions to reset itself immediately upon becoming reenergized after eifecting the timing operation. In View of the fact that a directcurrent motor is utilized to drive vthe timing cam, the timing period may be readily adjustedv by varying the motor speed. The device is capable of functioning satisfactorily over an ambient temperature range of from 50 C. to +50 C.

Another important feature of the invention is that it provides for an electrical timing adjustment instead of a mechanical adjustment through the use of a simple variable resistor or potentiometer. Vibration has no effect upon the iming period or cycle in view of the fact that the timing cam is positively driven by an electric motor.

While I have shown and described three specic embodiments of my invention in more or less schematic form, lit is to be understood that changes and modifications may be made therein without departing from the principles of the invention and that it may take other forms as determined by manufacturing processes and methods.

I claim as my invention:

1. A time delay relay device comprising, a control relay having an operating winding and normally open contact members, a cam-actuated switch having normally-closed contact members and a cam disposed to actuate said contact members to their open position in response' to a predetermined movement thereof from a normal start position, means connected with the cam normally biasing it to its normal start position, circuit means. including said normallyclosed contact members connected to control the energization of said relay operating winding, a driving motor for actuating said cam-actuated switch, an energizing circuit connected to operate said motor including the normally open contact members of the control relay, electrically actuated clutch means mechanically interposed between the motor and cam operable to mechanically connect and disconnect the motor to and from the cam, circuit means including a switch connected to control the energization of the clutch means, a switch disposed to be actuated to two different circuit controlling positions `"directly in accordance with the position of the clutch means, said switch being connected to both the energizing circuit for the control relay and for the motor so as to be eil'ective in one position to complete the energizing circuit ior the control relay through the normally-closed contact members of the cam-actuated switch in response to the disengagement of the clutch means to close the normally open contact members of the control relay and eifective in the other position to complete the energizing circuit for the motor through the contact members of the control relay when said clutch means is engaged, whereby the motor is energized and then deenergized upon the deenergization of the control relay and the opening of its contact members in response to the opening of the cam-actuated switch.

2. A time delay relay device comprising, a control relay having an operating winding and a normally open contact element, an energizing circuit connected to the operating winding of said relay including said normally open contact element of the relay, a cam-actuated-switch including normally-closed contact members also connected in said energizing circuit for the control relay, and a cam disposed to actuate said contact members to their open position in response to predetermined movement thereof from a normal reset position, means connected with Athe cam normally biasing it to its normal reset position, a motor for actuating the cam-actuated switch, an energizing circuit including the normally open contact element of the control relay connected to the motor, a magnetically actuated clutch including a solenoid interposed in mechanical driving relation between the motor and the cam of the cam-actuated switch, said clutch being normally biased to its engaged position when the solenoid is deenergized, a control switch disposed to be actuated to different controlling positions in accordance with the position of the clutch, said switch having contact members which are connected in the energizing circuit for the control relay in parallel circuit relation with the contact element of the control relay and which are closed to energize the control relay and close its contact element when the clutch is disengaged and additional contact members which are connected in the energizing circuit for the motor and which are closed to complete the energizing circuit of the motor through the closed contact element of the control switch when the clutch is engaged.

3. A time delay relay device comprising, a control relay having an operating winding and normally open contact members, an energizing circuit connected to said winding, a cam-actuated switch having normally-closed contact elements connected in said energizing circuit and a cam disposed to actuate said contact members to their open position on predetermined movement of the cam from a normal starting position, means connected with the cam normally biasing it to its normal starting position, a motor i'or actuating said cam-actuated switch, an energizing circuit connected to operate the motor, a normally engaged clutch mechanically interposed between the motor and cam-actuated switch, electromagnetic means operable when energized to actuafe the clutch to its disengaged position, an energizing circuit connected' to the electromagnetic means, a control switch disposed to be actuated in accordance with the movements of the clutch between two diiierent contact making positions corresponding to the engaged and disengaged positions oi' the clutch, said control switch being effective when in one contact making position corresponding to the disengaged position oi the clutch to complete the energizing circuit of the control relay through the normally closed contact elements of the cam-actuated switch and effective when in its other contact making position corresponding to the engaged position o! the clutch element to complete Ithe energizing circuit for the motor, said the motor including said normally open auxiliary contact members of the control relay which are closed when said relay is energized, and switch means for selectively controlling the energizing circuit of the electromagnetic means.

4. A time delay relay device comprising, a control relay having an operating winding, a camactuated switch having normally-closed contact members and a cam disposed to open said contact members on predetermined rotation thereof from a start position, means connected with the cam normally biasing it to its start position, circuit means including said normally closed contact members of the cam-actuated switch connected to control the energization of said control relay winding to operate said relay, a direct-current drive motor for the cam-actuated switch, an'

electromagnetically operated clutch mechanically interposed between the cam and drive motor, said clutch being normally engaged when deenergized, circuit means including a switch connected to control the energization of the clutch, additional circuit means including a switch actuated to closed position in response to the deenergization of the clutch connected to energize the motor to eiect the opening of the contact members oi the cam-actuated switch to deenergize the control relay, and Variable resistance means connetced in the energizing circuit of the motor for determining the speed thereof to control the length of the timing period by controlling the speed of movement of the cam.

5. A time delay relay device comprising, a control relay having an operating winding and a normally open contact element, an energizing circuit including said normally open contact element connected to said relay Winding, a camactuated switch having normally-closed contact members connected in said energizing circuit and a rotatable cam disposed to actuate said contact members to their open position in response to a predetermined degree of rotation of said cam from a start position, spring means normally biasing the cam to its start position, a directcurrent drive motor, an energizing circuit including the normally open contact element of the control relay connected to said motor, an electro magnetically operated clutch mechanicallyinter-` posed between the cam and drive motorsaid clutch being disengaged when energized, switch means actuated to two diierent circuit controlling positions in accordance with the engaged and energizing circuit iol'y disengaged positions of the clutch for controlling the energizing circuits of the motor and control relay, saidv switch means being operable in one circuit controlling position when the clutch is energized and disengaged to shunt the normally variable resistor connected in series circuit relar tion with the armature of the motor for varying it speed to control the speed of rotation of the cam and thereby the timing period.

6. A time delay relay device comprising, `a control relay having an operating winding, a camactuated switch including normally-closed contact members and a rotatable cam disposed to actuate said contact members to their open position in response to a predetermined degree of rotation of saidcam from a starting position, adjustable stop means determining the starting position of the cam, means normally biasing the cam to its starting position, circuit means including said normally-closed contact members connected to control the energization of said control relay winding to, operate the control relay, a direct-current drive motor, an electromagnetically operated clutch interposed between the cam and drive motor, circuit means including a switch connected to control the energization of the clutch, additional circuit lmeans. including a switch actuated to closed circuit controlling position in direct response to the engagement of the clutch connected to control the energization of the motor, and a variable potentiometer connected with the armature circuit of the motor for varying is speed to determine the length of the timing period by controlling the speed of rotation of the cam.

7. A time delay relay device comprising, a control relay having an operating winding, a cam-actuated switch including normally-closed contact membersand a rotatable cam disposed to actuate said contact members to their open position in response to a predetermined degree of rotation of said cam from a starting position, means Ynormally biasing the cam to its start ing position, circuit means including said normally-closed contact members connected to vcontrol the energization of said control relay winding to effect its operation, a direct-current drive motor, an energizing circuit connected to said Inotor, a normally engaged electromagnetically operated clutch mechanically interposed between the cam and drive motor, switch means actuated directly in accordance with the position of the clutch, said switch means having contact members connected in the energizing circuit of the motor and which are closed to energize the motor in response to the engagement of the clutch, additional circuit means including a switch connected to selectively control the energization of the clutch, and a variable potentiometer connected to the armature and eld circuits of the motor for Varying its speed to determine the length of the timing period by controlling the speed of rotation of the cam.

8. A time delay relay device comprising, a control relay having normally open contact members and an operating winding, an energizing circuit connected to the winding of said relay, said circuit including its normally open contact members, normally-closed contact members connected in said energizing circuit, a cam for actuating the normally-closed contact mem- -bers to ytheir open position on predetermined movement of the cam from a start position, means normally biasing the cam to its start `po sition, a motor for actuating the cam, an energizing circuit including the normally open contact members of its control relay connected to the motor, a normally engaged clutch element mechanically interposed between the motor and cam, a solenoid operable when energized to disengage the clutch, circuit means including a switch connected to selectively control the energization of the solenoid, and switch means disposed to be actuated to one circuit controlling position when the clutch is disengaged to complete the energizing circuit of the controlrelay winding through the normally closed camactuated contact members by shunting the normally open contact members of the control relay and to another circuit controlling position when the clutch is engaged to complete the energizing circuit of the motor through the closed contact members of the control relay.

9. A time delay relay device comprising, a control relay. having an operating winding, circuit means connected to said relay winding to control the energization thereof, normally-closed contact members connected in said circuit means and operable to open position to deenergize said relay, a rotatable cam disposed to actuate said contact members to their open position on predetermined rotation of the cam from a start position, means connected with said cam to normally bias it to its start position, adjustable stop means engaging a portion of the cam to determine its start position, a driving motor for actuating said cam, an energizing circuit connected to said motor, an electrically actuated clutch mechanically interposed between the motor and cam operable to connect and disconnect the motor to and from the cam, saidv clutch being normally engaged when deenergized, switch means including an energizing circuit connected to the clutch for selectively controlling the energizationof the clutch, and switch means disposed to -be actuated in accordance with the position of the clutch connected to control the energizing circuit of the motor, said switch means being actuated to its closed position when the clutch is deenergized and engaged, whereby the motor is energized in response to the engagement of the clutch to effect the opening of the normally-closed cam-actuated contact members and the deenergization of the control relay' winding with a time delay as determined by the predetermined rotation of the cam.

10. A time delay relay device comprising, a control relay having normally open contact members and an operating winding, an energizing circuit connected to said relay winding, a camactuated switch having normally-closed contact members connected in the energizing circuit of said relay winding and a cam operable to actuate said contact members to their open position on predetermined movement of the cam from a normal starting position, biasing means normally determining said normal starting position, a driving mot-or for actuating said cam, electrically actuated clutch means mechanically interposed between the motor and cam operable to connect 'I5 and disconnect the motor to and from the cam,

connected to shunt the normally open contact 10 Number members of the control switch to complete its energizing circuit and to another circuit closing position in response to the engagement of the clutch means connected to complete the enerl2 gixing circuit for the motor through the closed contact members of the control relay.

CLARENCE L. MERBHON. REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date 667,625 Hopkinson et al. Feb. 5, 1901 2,103,907 Kearsley Dec. 28, 1937 2,120,787 Lowkrantz June 14, 1938 2,385,013 MacNeill et a1 Sept. 18, 1945