US2538732A - Time delay relay - Google Patents

Description

Jan. 16, 1951 Filed May 31, 1946 W. D. MACG EORGE NVENTOR #444/4/1/ Q MCGfO/QGA ATTORNE a 1951 w. D. MACGEORGE 2,533,732

TIME DELAY RELAY Filed May 51, 1946 2 Sheets-Sheet 2 INVENTOR Mu MM 5 A/JGGZORGE @Z M v%%;

ATTORNEYS Patented Jan. 16, 1951 to Automatic Temperature Control 00., Inc., Philadelphia, Pa., 'acorporation of Pennsyl vania Application May 31, 1946, Serial No. 673,683

8 Claims.

This invention relates to time delay relays. It is among the objects of the invention: to provide improvements in time delay relays; to provide a double time delay relay by which the time of make of relay as well as the time of break of the relay, after respective making and interruption or breaking of the circuit thereto, are independently timed; to provide a double time delay relay for operating a Thyratron control circuit or the like by which, after closing the circuit, a predetermined time interval elapses during which the Thyratron tube is heated before the load circuit is established, and which, pursuant to a temporary interruption of the current for an interval less than that for which the device is predetermined, closes the load circuit again, without requiring such predetermined time interval to elapse and which, in'the event that the Thyratron has had time to cool below the safety point, reestablishes the preliminary warm-up time interval, the elapse of which is a prerequisite to the sequential closing of the load circuit; to improve differential mechanisms: to improve differential mechanisms for partial strokes; to improve the indicating qualities of time relays and the like; and many other objects and advantages of the invention'will become more apparent as the description proceeds.

In the accompanying drawings,

Fig. 1 represents a front elevation of the differential time delay relay of this invention, at the start of a timing interval prior to relay circuit closing. 4

Fig. 2 represents a transverse'section taken on line 2-2 of Fig. 1.

Fig. 3 represents a lateral section taken on line 3--3 of Fig. 2.

Fig. 4 represents a plan, partially in section, of the device of Fig. 1.

Fig. 5 represents a view similar to Fig. 1 with anchors the pinion gear II against rotation. On

parts broken away and with the relay at the close of the timing interval at the closing of the So far as the preferred form of the relay is concerned, it preferably comprises a unidirectional motor I0, supported on one side of a panel board 24, and driving a pinion gear II on the an axis parallel to that of the pinion gear II, a shaft I2 is journalled on the panel board 24, and toward the front end the shaft pivotally carries the depending lever arm I3, hanging or depending substantially vertically and movable in a con-- trollabl'e, relatively slight, oscillation 32 between its normal position held against the adjustable stop I4 by the spring deviceI5, andthe operating stud I6 of a micro-switch or the like II. A large sprocket I8 is journalled on a shaft 20 carried by the operating lever I3, in mesh with the alternate or selective driving stop pinion II. It will be seen that in a movement of lever I3 counterclockwise of and about the shaft I2 from its position of normal rest against the stop I l, the transverse movement of the lever I3 will impart rotation to the sprocket I8, when the pinion II is held locked. As viewed in Fig. 1, this rotation of the sprocket I8 will be clockwise. In a reverse movement of the lever re-traversing path 32, in moving from stud I6 tostop I4, the sprocket I8 is shifted bodily across the peripheral edge of the adjacent portion of the pinion I I in a counterclockwise direction of rotation. Although an exaggerated movement of the lever in either direction would bring the teeth of sprocket I8 out of mesh with the pinion gear II, this is guarded against in the normal operation of the device in nalled on the shaft I2, concentric witli the axis.

of the pivot of the lever I3, and the gear 2I is also in constant driving relation to the relatively small pinion gear 22 mounted on a shaft I9 journalled in the panel 24 and carrying a larger gear 23 on the rear face of the panel. The gear 23 on the back of panel 24 is in mesh with a relatively small pinion gear 25, of a shaft carrying the relatively large brake drum or stop gear 26. It will be observed that with drum 26 free to turn, the rota.- tion of the motor driven pinion II, through its meshing engagement with the sprocket I 8, will drive the entire train of gears, including the terminal drum element 26, in idle rotation while the lever arm I3 remains against the stop I4, unaffected by the drive from motor Ill. On the other hand, if the drum 26, and thus the entire train of recited gears to and including sprocket I8, is locked and held against rotation, then the driven rotation of pinion II, in its meshed engagement with the locked sprocket I8, causes sprocket I8- to function as a transversely movable rack, and by forcing the sprocket I3 to climb transversely on pinion II, it moves or takes the lever I3 with it transversely across in front of panel 24. This causes the lever I3 to leave stop I4 at the beginning of the timed interval determined by the closing of the circuit through the motor, and to traverse the, predetermined distance 32 between the edge remote from the stop I4 when in engaged relation thereto, and the control knob or button, It of the single pole, double thrown switch, such as a micro switch IT. This desired timed interval could only happen, however, when and; if the terminal gear or brake drum 26', and thus the; entire gear train, was locked against rotations.

To look the gear 26, selectively, an electromagnet Z'l is mounted on the panel 24, and is.

the periphery of the gear 26, to form a positive stop to the rotations of the gear train when the magnet is energized. When the magnet is deenergized, in the normal course, the lever arm 28 snaps up under the bias 29, removing. the tooth detent 30 from the meshed engagement with the ear 26.

The detent 30 on the lever 28 is located slightly off center, as far as. a vertical plane containing the axis of the brake drum or gear 26 is concerned, and this fact, in addition to the almost inevitable presence of a small residual back lash in the relatively long gear train, and the resilience of the lever 28, enables the detent 30, to enter directly between the. teeth of the gear 26, regardless of the setting of the adjustable stop I4, and it also enables easy and quick removal of the detent 36 from gear 26 when the electro-magnetic circuit is broken and the spring- 29 functions to snap the lever upwardly and away from the gear 25.

By coupling the motor I and the electro-magnet 21 in parallel with the power source, as shown in Fig. 6, with the circuit through the motor only passing through one side iii of the single pole, double throw, snap switch ll, there will be simultaneous energization of both the motor and the magnet when the main power switch 39 is closed. The electromagnet 21 is energized simultaneously with the starting of motor l0 and the detent 30 snaps in, to lock the gear train, and the rotatably locked sprocket. I8 starts to move transversely across the face of the panel 24, about: pinion II, driven by the motor It. If the closing of this circuit has also been accompanied by the closing of the circuit through the cathode circuit of the Thyratron tube, if this is the timed associated element, then by the time that the. lever I3 has moved across; the gap 32 (Fig. 1) to. a point such as to actuate the knob or control element I6 oi the switch H, the cathode circuit of the Thyratron has been on for a safe period so that the load circuit 343' controlled by circuit controller 33 of the switch I'l, can be cut in through the anode circuit of the Thyratronf This is accomplished by opening the circuit through the motor Iii, through circuit controller 3I of switch II, which stops the motor and holds the pinion I I stationary and thus the lever I3 in its extreme timed positioning against the actuating control device It. If everything proceeds properly, this is the operating condition, with detent 30 still engaged to lock the gear train and the motor I0 stopped, and with the load circuit coupled to the power lines.

With the parts as so far described, it will be understood that it will be necessary to start and q complete a new timed delay cycle before the power lines can be coupled to the load circuit after a break in the power circuit. This is assuming or the sake of the description that the power lines, are common to both the relay and to the load circuit. It will be clear that in the event of even a most transient stoppage of the power line supply, as when changing generators, for instance, the interruption of the circuit through the electr c-magnet 2'! enables the spring 29 to function to snap the lever 28 upwardly on its pivot to withdraw the detent 30 from the gear engagement. This instantly removes, the brake from the gear 25 and under the action of the spring I5 efiective on the lever IS, with the freely rotatable sprocket rotating about the stationary pinion Ii, the lever 23- snaps over into engagement. with the abutment I4, which simultaneously removes the pressure from actuator I6 of, the snap switch I], to successively break the load circuit. through the circuit controller 33, and to reestablish the connections with the power line circuit for ultimate closing of the circuit. through the motor II] when the power circuit is reestablished... This condition, maintains with, no further action until the power line circuit againbecomes closed, when the electro-magnet 27 again snaps the detent. 30 into mesh with the gear 25 as the motor It starts to run, to establish another timed interval before the load circuit again is; closed through actuation of the switch II. The relay with its timed delay as described, is of value in many situations where, safety is more important, than the mere saving of time, It will. be seen, however, that: if the break. in the power supply is purely transi- I! tory, even for a few seconds, perhaps the Thyratron would not have a chance, to cool to a point below which it would. be safe; to reenergize: same immediately after the power lines. were reestablished, following on a break therein; In other words, from the, safety standpoint, even. opening of the cathode circuit for as long as twentyseconds, as a, purely illustrative. instance, and then closing it would find the output of the tube from the anode. circuit, when. also reenergized, adequate for the load purposes. placed? upon it. Thus, if the cathode circuit were closed again within the safe limits and the load circuit were also closed again within the same safe limits, it will be clear that it would be a waste of time to be forced to. await the complete timed cycle of operation incident to bringing the lever 13 from its repose against the abutment l4. through the timing cycle to a point of actuating the switch H.

In order to. effect a safe timed delay on the break, as well as on the make, of the work or load circuit, it is preferred to provide a thermal latch 34', comprising a suitable bi-metallic device energized by the secondary of" a transformoi: 3.5,, theprimary of: which is connected directly across the power circuit. The lei-metallic element 34 has a latching flange 31 juxtaposed to the free endoi the lever: 28 and is so arranged that when suitably heated by the flow of current through the element, for a sufficient time interval, the latch flange 3?; moves over the. nee

end of the depressed lever 28, which at the time, of course, has been pulled in by the electromagnet, as shown in Fig. 5. mother words,

- had been no interruption; This saves repeating when the master circuit switch 39 is closed through both power lines, the electro-magnet 21 is energized, pulling in the lever '28, and at the same time the bi-metallic element 34 is energized and begins to warm up. With a time delay, which is preferably adjustabl to accord with. the various uses of the device, by relative adjustments of the support 36 to move the latch 31' in its plane toward or away from the end of lever 28, the flange 31 of the latch moves slowly across the lever, 28 in increasing overlapping contact therewith as the element 34 becomes hotter. As long as the bi-metallic element retains sufficient heat to maintain a suitable bend, the flange 31 thereof latches the lever 28 by overlapping same and holds it against rising to release the detent 3&3 from the gear 26. With the secondary timed delay arrangement just described, it

may well be that for the purpose of savingpower, I

the electro-magnet 21 and the motor H] are arranged in parallel and both are controlled by the circuit controller 3| of switch [1,, so that when the predetermined timed interval between the starting of the motor It and the breaking of the circuit through switch elements 3| of switch H has elapsed, and the load circuit has been established through the switch elements 33, both the motor 10 and electro-magnet 21 are simultaneously deenergized, and remain so during the continuance of uninterrupted flow through the power lines. As during this entire time, however, the circuit has been flowing in the bi-metallic element 34, flange 31 thereof has attained a maximum overlap on the lever 23, for which it is designed, and holds the lever 28 "in with the detent 3B engaging and locking gear 26 so that the gear train meshing therewith remains locked. Itis preferred, however,

that-the circuit connections for the electro-mag' net be similar to those disclosed in Fig. 6.

When there is an interruption in the power lines, which if held too long would endanger the Working or load circuit elements, if the load circuits were remade immediately when the break ended with the remaking of the power circuits, the first activity following upon the break of the; line connection, is the opening of the circuit through the electro-magnet 27, and the imposition of the spring bias to urge the lever 28 out.

This is ineffective, however, because of the latching function of flange 31. At the same time, the heating circuit through the bi-metallic element 34 is interrupted and the element starts to cool. As it cools, it straightens out and gradually withdraws the flange 31 from overlapping the lever 23. If at any time before complete withdrawal of the flange 31 from its overlyinglatching relation with the lever 28, the power circuit is again completed, that is, within the time set bythe initial normal disposition of the bi-metallic element 34 and flange 31 relative to the lever 28, the power lines through the load are reestablished instantaneously. This is because the lever [is has remained in operative contact with the actuating stud it of the switch 11, the latter remains with circuit controller 33 thereof closed, and, therefore, the motor Ill and electromagnetic coils 2? controlled by circuit controller 3| of that switch, have not been placed in circuit with the power lines. As the load circuit the time delay before the load circuit can be reestablished and speeds up the operation of the machine associated with the relay.

When, however, the duration of the break in the power line exceeds that for which the device is preset, the bi-metallic element 34 has an op portunity to cool sufficient as to completely withdraw the flange 3'! from the overlapping relation tothe lever 28, which promptly snaps upwardly, withdrawing the detent 30 from the gear, which is immediately followed by the rapid idle rotation of all of the gears in the train under the urge of the spring bias l5, permitting the lever is to move away from the switch H to engage the abutment M, and thus to set the conditions for the ultimate reestablishment of the actuating circuit, by which to restart the load circuit after the predetermined delay prior to such restarting incident to the movement of lever I3.

It will be' evident that in many cases it is of importance to know how far along in a given cycle of operations the timing delay device may be, and to this end suitable indicating means is associated with parts of the mechanisms having preferably an oscillation of less than 360 in the normal operation of the device. To a suitable member of restricted angular movement, such as to. the shaft IQ. of the first pinion gear 22 in the train above the sprocket [8, a pointer 41! is affixed in position'to overlie the graduations of the indicating dial 38, and so arranged as to move on its axis in shaft is as a relatively small angular ,function of the angular movement of the lever I3 in its timing function movement. Of course, for this purpose also, the indicator 4!! could be carried directly by the lever 13 for the same effect.

It will be apparent that if with the gear train completely locked so that the sprocket l8 climbs transversely over and relative to the rotatin pinion gear 8 l actuated by the motor, the lever it moves a given fraction of an inch in a given time interval, then if the braking on gear 26 were look the gear train from above similarly to the lock accomplished by the detent 36 on gear 25. On, the other hand, if gear 25 were driven in a given direction at a given different rate of speed from that at which the pinion gear I l were driven, the progress of the lever 13 would be as the diiferential between the two speeds, or as the sum of the two speeds if the directions of rotation were properly coordinated for the purpose. It will be seen that with the device as shown in Fig. 8, with motors 3| and I0 turning in mutually cancelling directions at nearly the same speed, the rate of rate indeed. The possibilities with either different speeds of the motors, or with diiferent ads justments for speeds of the respective gears ii and 25, for adjustable timing intervals for timing relay purposes are practically without limit.

'The advantages of the invention will be apparent to those skilled in the art.

Having thus described my invention, I claim: 1. A time delay relay comprising a lever having an arc of movement about a pivot, a sprocket assays a gear, means for mounting the sprocket gear "ro tatably on and for bodily movement with the lever between the pivot and the freeend of the lever for movement in translation with said lever, a pinion gear meshing with said sprocket gear on the opposite side of said sprocket from said pivot and fixed against translational movement, motor means for driving the pinion in one direction,

stop means, spring means urging the lever toward one side of its arc of movement against said stop means, a switch, operating means for the switch located at the other side of the said are of movemom of said lever, electrical means selectively operable for locking said sprocket against rotation and for unlocking said sprocket, means for operating said electrical means, means independent of said electricalmeans establishing anoperating circuit for the motor means through said switch broken when said switch operating means is actuated by said lever, said sprocket when locked serving as a toothed rack member movable bodily by the pinion to move the lever in a timed interval through its arc of movement to engage and actuate said switch-operating means to stop the motor and hold said lever against said switchoperating means. until said means for operating is actuated to unlock said sprocket to permit the lever to leave the engagement with the switchoperating means under the influence of said spring.

2. A time delay relay comprising a frame, an element supported on the frame for movement from a starting position to a final switch-actuating position, a sprocket journalled on said means and movable bodily therewith, a motor, a pinion gear journalled on the frame and in mesh with the sprocket gear, means operatively coupling the motor and the pinion gear to drive the latter when the motor runs and to hold the pinion gear stationary when the motor is stationary, a switch having two positions and controlling two different circuits, means located at said switch actuating position and engageable by the movable means to open and close the two different circuits in alternation, means locating said motor in one of said controlled circuits for running the motor until the switch has been actuated by said movable means, means operative during the time of running of said motor at least for locking said sprocket against rotation during rotation of the driven pinion to secure the movement of said means, a load circuit controlled by the other'of the two controlled circuits of the switch which is closed when the movable means engages the switch actuating means to open the circuit through the motor, and thermal means holding said locking means in looking operative relation to said sprocket to prevent rotation of the sprocket relative to the stationary pinion for a predetermined interval, and means urging the movable means from its switch actuating position to the variable starting position operative when the sprocket is unlocked for rotation on the 'statiom ary pinion gear.

3. A time delay relay comprising a gear train having primary and secondary terminal gears, a member movable in a predetermined path between limits, spring means urging the member against one of said limits, one of said terminal gears mountedrotatably on'said'member, a pinion gear fixed for rotation adjacent to said path and in mesh with the terminal gear mounted onsaid member, a motor for driving the pinion gear, electro-magn'etic means for brakingthe otherof saidterminal gears to lockthe gear train'against rotation, means for'energizing the electr c-magnetic means and the motor to cause the pinion gear todrive the locked terminal member to move the member away from one limit toward the other in a timed interval against the resistance of said spring means, a two position'switch having contacts such that in a first unengaged position of the switch a circuit through said motor is established, and in the other position the circuit through the motor is broken and a circuit is established through a load, means at the limit'of the predetermined path operable by said member the circuit through the motor while breaking the load circuit, and thermal means for delaying for a predetermine'd'interval the release of the braking means after the interruption of the circuit through the electro-magneticmeans.

4. A time delay relay comprising a frame, an element supported on the frame for movement between starting and switch actuating positions, a sprocket journalled on said element and movable bodily therewith, a motor, a pinion gear journall'ed ontheframeinmesh with the sprocket and in drivenengagement w-ithsaid'motonmeans for urging the element "toward its starting position, means'foi" locking the sprocket againstrotation to enable driven actuation of the pinion to move the element from its starting position toward its switch actuating position against the resistance 'of the mean's foru'rging at a timed rate, and separate meanshaving a predetermined time delay for releasing the means for looking to permit the sprocket to turn idly relative to the pinion while moving bodil with-said'element to enable the means for urging the element tomove it to its starting position.

5. A time delay relay comprising a frame, an element supported on the frame for movement from a starting to a switch actuating position, a sprocket journal-led on said element and movable bodily therewith, a motor, a pinion gear journalled ontheirain'ein mesh with the sprocket and in driven engagement with said motor, means for urging the element toward its starting position, means for locking the sprocket against rotation to enable driven actuation of the pinion to move the element from its starting position toward its switchactuating position against the resistance-of the means for urging at'a timed rate, said locking means including an electromagnetically operated device and means closing a circuit therethrough in effective parallelism with the circuit through the motor, a switch in position to be actuated by said element at the end of its movement and including a circuit controller through which the-motor circuit passes, means establishing'a loadcircuit, a circuit controller for the load circuit controlled by said s'witchin alternation tothe motor circuit, and a thermal latch, means establishing a circuit through the thermal latch in effective parallelism with the circuit through the electro-magnetic device, said latch when suitably heated being arranged as-a d'etent to therel'ease of said brake when the electromagnetic circuit is broken, and arranged when suitably cooled topermit the release of said elect'ro-magnet icdevice.

6. A double time delayrela-y comprising a sup-- 9 port, an element mounted for pivotal movement about the axis on the support, a sprocket gear journalled on the element for bodily movement therewith, a gear concentric with said axis in permanent mesh with said sprocket, a train of gears in mesh with said concentric gear and terminating in a braking gear rotatable on the support, a pinion journalled on the support and in permanent mesh with the sprocket, a motor for driving the pinion, a stop, a spring for urging the element against the stop, a switch-actuating means spaced from the stop in the path of movement of said element, a lever overlying said braking gear, resilient means urging the lever away from said braking gear, electro-magnetic unlock the train of gears but operative when,

cooled to withdraw said flange to permit such unlocking, and means establishing a circuit through the thermal element effectively in parallel with the circuit through the electro-magnetic means, said thermal element arranged to impose a time interval after the interruption of the circuit through the electro-magnetic device and the thermal unit before permitting unlocking of the train of gears and their idling rotation in moving the element back toward the starting position. a

7. In time delay relays, a support, a lever, means mounting the lever for oscillation on a pivotal axis relative to the support, a sprocket, means mounting the sprocket for rotation on the lever on an axis parallel to the said pivotal axis, a first and a second abutment means on the support in relatively spaced relation in and limiting the path of oscillation of said lever, a circuit controller having a yieldable actuating element, one of said abutment means comprising the yieldable element of said circuit controller, motor means, circuit means for the motor controlled by said circuit controller, a pinion gear mounted on the support in driven relation to the motor means on an axis parallel to said pivotal axis generally between said first and second abutment means and in mesh with said sprocket, electrical means independent of the said circuit means operable selectively to unlock or lock said sprocket against rotation on its axis, the spacing between the abutment means being closer than would permit the pinion and sprocket to unmesh through relative bodily movement of the sprocket with the lever, means for biasing the lever toward one abutment means, said sprocket when locked by said independent electrical means functioning as a rack to move the lever against its bias under torque from said pinion during the closing of the motor circuit, said circuit controller opening said circuit to stop the motor when the yieldable member thereof has been engaged by said lever with the lever continued in engagement with said yieldable member, and said sprocket when unlocked by said electrical means turning freely to permit the lever to respond to the bias and move toward the abutment means toward which it is biased regardless of the running of said motor initiated by closing of the motor circuit when the yieldable means is released by said lever.

8. In time delay relays, a frame, a lever, means mounting the lever in a substantially pendular suspension'on a pivotal axis to the frame, a sprocket, means mounting the sprocket on the lever on an axis in parallel spaced relation to the pivotal axis, an adjustable abutment on said frame in the path of arcuate swing of said lever generally on one side of a substantialy vertical line passing through said pivotal axis, switch means comprising an abutment element in the path of arcuate swing of said lever generally on the other side of such substantially vertical line and transversely spaced from said abutment, a pinion gear, means mounting said pinion gear on the frame on an axis parallel to the pivotal axis on the other side of said sprocket from said pivotal axis and disposed generally medially between the abutment and said abutment element, a motor for driving said pinion gear, said pinion gear being in constant mesh with said sprocket and the spacing between the abutment and said abutment element being sufliciently close as to limit the arcuate swing of said lever between the abutment and the abutment element always to a swing smaller than would be necessary to unmesh the pinion gear and sprocket pursuant to bodily translation of the sprocket with said lever in its arcuate swing, means for biasing the lever toward the abutment, separate electrical means for selectively locking and unlocking said sprocket to prevent or permit rotation of said sprocket on its said axis on the lever, said sprocket when locked functioning as a rack to move the lever against its bias under torque from said pinion gear and when unlocked turning freely relative to said pinion gear to permit the lever to respond to the bias in returning to engagement with said abutment, and circuit means independent of said separate means for selectively locking controlled by said switch means for stopping said motor when the lever engages the abutment element.

WILLIAM D. MACGEORGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number

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