US2744573A - Time delay program relay - Google Patents

Description

y 8; 1956 A. L. JUDSON ETAL 2,744,573

TIME DELAY PROGRAM RELAY Filed Feb. 15, 1954 2 Sheets-Sheet l 2 Z :::I' I:

INVENTOR. A/ber/ L. Judson By Rober/ f. Lac/2 W y 8, 1956 A. L. JUDSON EI'AL 2,744,573

TIME DELAY PROGRAM RELAY Filed Feb. 15, 1954 2 Sheets-Sheet 2 INVENTOR. A/ber/ L. Judson Ruben Zach United States Patent TIME DELAY PROGRAM RELAY Albert L. Judsonaand Robert E. Lach, Portland, 0reg., assignors. to Iron- Fireman Manufacturing Company, incorporation of Oregon Application February 15, 1954, Serial No. 410,165 4 Claims. (Cl. 1611) This invention relates generally to electrical relays and more particularly to relays adapted-to delay the relayed' signal in proportion to another time variable.

Specifically the'relay of this invention is adapted to delay the application of the plate voltage to an electronictube for a sufficient time after the beginning of hcating of the cathode element for the elements of the tube" to attain their'respective desired starting temperatures'.

It should'be understood that this is not the first relay which'has been developed and provided for this purpose since others, more complicated and more expensive, have been used.

It is'therefore a principal object of this invention to provide such a relay of great simplicity relative to its required function.

A relay for the stated purpose has two timingfunctions; The first of its functions is to close the 1oad,.or plate voltage applying switch, a fixed time after receipt ofia starting signal if the electronic tube is cold. The second of its functions is variably to delay the closing of the load switch after an interruption of power supplied to the tube.

Specifically the program required of. the present invention is to close its load switch in three minutes and fifty-five seconds after power is first applied to the tubes cathode heater. Then, if there is an interruption of power to the tube of less than eight and. one-half seconds, to maintain the load switch. closed. If the power interruption lasts eight and one-half seconds, the relay is required to open its load switch and maintain the load switch open for a minimum time of one minute.- Should the power interruption last longer than eight andonehalf seconds and. variably up to a total of six minutes, the relay is required to delay the reclosing of its load switch for one minute plus one-half the amount of time over eight and one-half seconds during which. the power interruption lasts.

It isa second object of this invention tov provide such a relay having. the. stated program characteristic, itbeing.

understood thatthe proportions-of parts and selection of elements may be such as to give any similar program desired.

The novel and useful elements and arrangements discovered and invented jointly by us for the present purpose and. to which we lay claim for these and all analogous. uses are described'in the following'explanation re-' ferring to the attached drawing in which- Fig. lis a viewof our relay in side elevation.

Fig. 2 is a sectional view of our relay along the line 2-2' of Fig. 1.

Fig. 3 is a fragmentary plan view along'the line 3-3' Fig.4 is a fragment of the sectional view of Fig. 2 taken along the line 4-4 of Fig. 3.

Fig. 5 is similar to Fig; 4 with the cycle'further advanced.

Fig. 6 is similar. to. Fig. 5 with the cycle still further advanced.

Like numerals of reference refer to like parts in the several figures of the drawing.

It should also be noted that in each of the figures of the drawing parts have been omitted for the purpose of better disclosure of the remaining parts and their interaction.

As shown in the drawing our relay comprises a base plate 11 on which are secured upright bearingplates 12 and 13 by screws 14 and 15 respectively. Cam shaft 16 journalled in plates 12 and 13 is coupled by coupling 17 to rotor shaft 18 of spring motor 19 having feet 20 secured to base 11 by screws 21. Synchronous timing motor 22 secured to plate 13'by screws 23 through motor case ears 24 has secured to its output shaft 25 drive pinion 26 permanently meshing with gear 27 havinghub 28 freely rotatably supported on shaft 16. Also freely rotatably supported on shaft 16 is hub 35 of gear 29 permanently meshed with pinion 30 secured to pinion 31 with both pinions 30 and 31 freely rotatably supported on pinionshaft 32 journalled in toggle lever clip 33 and guided formotion radial to shaft 16 in slots 34 in plates 12 and 13.

Timing cam 36 having hub 37 secured on shaft 16 is perforatedwith arctuate slot 38 adapted to receive cam drive pin 39 secured to gear 29. The angular length of slot 38 and the diameter of pin 39 are selected to allow a maximum angular movement ofgear 29 with respect to cam 36 of fifty-five and three-quarters degrees. Spring 40 biases pin 39 and gear 29 toward clockwise movement relative tocam 36 as viewed in Figs. 2, 4, 5 and 6.

U-sectioned' toggle lever arm 41 having back plate 42 and bottom plate 45 is freely rotatably supported at one endon pin 43 secured in plates 12 and 13 and its other end is hinged. by pin 44 to toggle lever clip 33. Tension spring 46 secured between bottom plate 45 of toggle lever 41 and stationary pin 47 secured to plate 12 biases toggle lever. 41 towards counter-clockwise movement as seen in Fig. 2. Stop 48 secured to plate 13 by screws 49 limits the clockwise movement of lever 41.

Electromagnetic operator 50 secured to plate 13 has magnetically operatedarmature 51 (see Fig. I) extending' laterally across and resting against back plate 42 of toggle lever 41. Armature 51 is guided as shown in notch 52 in plate 13. Clip 53 secured to plate 12 by screw 54limits. the release movement of armature 51 and thus-limits. the counterclockwise movement of-toggle lever 41 under the bias of spring 46. When operator 50 is energized through wires 53a and 54 from direct current source 55'by the closing of starting switch 56 armature 51 moves inwardly pressing toggle lever 41 with'it against the bias of spring 46 and moves pin 44 upward causing pinions 30, 31 on pin 32 guided in slots 34 to move radially. toward gears 29 and 27 respectively and causing pinion 31 to mesh with gear 27. It should be emphasized that pinion 31. and gear 27 have relatively small and therefore radially short, teeth while pinion 30 and gear 29 have relatively large, and therefore radially longer, teeth. Thus when operator 50 is deenergized and toggle lever 41 is moved counterclockwise by spring 46 until stopped by clip 53, pinion 31 is out of mesh with gear 27 but pinion 30. remains meshed with gear 29 at all times. Therefore when. operator 50 is deenergized pinions 31, 30' and gear 29 are free of control by gear 27, but when operator 50 is energized gears 27 and 29 are coupled through pinions 30, 31 and if motor 22 is energized through. wires 57, 58 and switch 60 from electric power source 59, gear. 29 is driven by. motor 22 through pinion 26, gear 27, pinion 31 and pinion 30. motor 22 is selected to drive pinion 26 at 2 R. P. M.,

Since:

sincethe tooth ratio of pinion 26 to pinion 31 is 1 to 2 and since the tooth ratio of pinion to gear 29 is 1 to 6, gear 29 will be driven by motor 22 at a constant rate of one-sixth R. P. M. or an angular rate of one degree per second in a counterclockwise direction as seen in Figs. 2, 4, 5 and 6.

Switch 60 is seen to comprise a pair of terminal straps 61, 62 insulatedly secured by rivets 63, 64 between insulation blocks 65, 66 to bracket 67 secured to plate 13 by rivets 68. Secured at one end to terminal strap 61 is resilient switch blade 69 carrying movable contact 70 biased by blade 69 towards stationary contact 71 carried by terminal strap 62.

Spring actuated motor 19 is a common type of spring actuated timer equipped with an escapement mechanism to drive cam shaft 16 at a coratant rate of one-twelfth R. P. M. in a clockwise direction as viewed in Figs. 2, 4, 5 and 6. Since drive pin 39 is secured at one end to gear 29 and is adapted to engage cam 36 with the other end of pin 39 in slot 38 of cam 36 it is seen that when electric motor 22 is energized it can drive shaft 16 through pin 39 and cam 36 in a counterclockwise direction at a rate of one-sixth R. P. M. and wind the actuating spring of spring motor 19, but if motor 22 is dis engaged from gear 29 by the deenergization of operator motor 19 will drive shaft 16 and cam 36 in a clockwise direction at a rate of one-twelfth R. P. M. The drive of cam 36 by motor 22 is limited by the opening of switch by the engagement of the free end of switch blade 69 by insulating disk 72 secured by rivet 73 to bracket 74 secured to gear 29 by rivet 75. See Fig. 6. The drive of cam 36 by motor 19 is limited by the abutment of radial edge 76 of cam 36 with stop bracket 77 secured to plate 12 by rivets 78.

Pivotally carried on cam 36 by pivot pin is latch lever 80 formed'with latch 81 at one end and carrying roller 82 on pin 83 at its other end., Compression spring 84 secured at one end to cam 36 and at its other end to lever 80 near pin 83 biases lever 80 towards clockwise rotation about pin 79 which motion is limited either by lever 80 striking drive pin 39 or stop pin 85.

With drive pin 39 (see Figs. 2 and 3) biased by spring 40 towards the end of slot in which it .is shown in Figs. 2 and 3 and with cam 36 against 77 which limits its clockwise motion, with motor 22 energized and operator 50 deenergized, the mechanism is ready to begin a timing cycle when operator 50 is energized and motor 22 is coupled to shaft 16 as previously explained. Gear 29 and drive pin 39 travel counterclockwise with cam 36 held sta- L tionary against stop 77 by spring motor 19. Overcoming 4 of fifty-five and three-fourths seconds until it strikes the forward end of slot 38 and then carries cam 36 with it until load switch S5 is closed and motor switch 60 is opened. The mechanism of load switch 85 will now be explained.

Bracket 86is secured by screws 87 to insulating plate 88 secured to plate 13 by screws 89. Resilient switch blade 90 carrying movable contact 91 of switch 85 is secured at one end to bracket 86 and is biased at its other or free end towards contact of contact 91 with stationary contact 92 carried on bracket 93 secured by rivets 94 to insulating plate 95 secured to plate 12 by screws 96. Load circuit wires 97, 98 are secured to switch terminal brackets 93 and 86 respectively by screws 99 and 100.

Bell crank 101 is formed with vertical pivot slot 102 adapted to receive pivot pin 103 fixed to plate 12. Spring 104 secured at one end to bell crank 101 and at the other to stud 105 secured to plate 12 biases bell crank 101 downwardly and counterclockwise as viewed in Fig. 2. Nylon cam rider 106 is secured by rivets 107 to the upper end of bell crank 10]. Flange 108 formed on the lower free end A of hell crank has its upward motion limited by screw 109 threaded into lip 110 punched from and part of plate 12. Contacts 91 and 92 of switch 85 are opened against the bias of blade 90 by upward motion of nylon disk 113 secured to the lower leg of bell crank 101 by rivet 111.

The operation of load switch 85 is as follows. Follow ing the start of the timing period as above explained pin 39 travels for fifty-five and three-fourths seconds .in slot 38 and then picks up cam 36 and continues to run counterclockwise. When cam 36 has progressed for seconds pin 39 has been travelling 230 and three-fourths seconds and forward edge 112 of cam 36 strikes the under side of cam follower 106 which is carried upward against the bias of spring 104. At this time slot 102 raises along pin 103 further opening switch 85 as bell crank flange 108 pivots on screw 109 and bell crank 101 pivots clockwise. After an additional travel of cam 36 of four and one-quarter seconds or a total travel of pin 39 of three minutes and fifty-five seconds bell crank 101 has moved clockwise sufiiciently for cam follower 106 to slide off the radial edge 112 of cam 36 and due to the bias of spring 104 bell crank 101 slides vertically downward guided by pin 103 in slot 102 and cam follower 106 resting against the arcuate outer edge of cam 36. Disk 113 falls with bell crank 101 and due to the bias of blade 90 contacts 91, 92 of switch 85 close. It is thus seen that our relay times out a delay of three minutes and fifty-five seconds after operator 50 is energized before load switch 85 is closed, and immediately after load switch 85 is closed disk 72 carried by gear 29 on bracket 74 strikes blade 69 of switch 60 and opens the circuit of motor 22 to halt the progress of shaft 16 and cam 36.

Once a communication system is operating it .is important that it keep operating as scheduled. However, power interruptions will occur and when they do occur it is important to resume operation as soon as possible after power is restored. In the particular system for which the form of our relay here typically shown is adapted for the purpose of applying plate voltage to an electronic tube only after the tube is thermally stabilized it has been found that for a power interruption of up to eight and one-half seconds voltage can be restored to the plate circuit imme diately on the restoration of power. Therefore on a power interruption of up to eight and one-half seconds voltage can be restored to the plate circuit immediately on the restoration of power. Therefore on a power interruption signalled by the deenergization of our operator 50 our load switch 85 will not open for eight and one-half seconds. If the power interruption lasts eight and one-half seconds the tube should be heated for one minute before voltage is restored to the plate circuit. If the power interruption lasts longer than eight and one-half seconds the tube should be heated for one minute plus one-half the time .in excess of eight and one-half seconds that the power interruption lasts. And finally if the power interruption extends for six minutes it is assumed that the tube is cold and the full heating delay of three minutes and fifty-five seconds is required before plate voltage is applied. As above noted power interruption to the system is evidenced at our relay by the deenergization of operator 50. Plate voltage to the tube is applied on closure of load switch V toggle arm 41 drops releasing pinion 31 from mesh with gear 27, gear 29 is free to rotate on shaft16 except for its restraint by latch 81 on pin 39 and the bias of spring 40. Also shaft 16 with cam 36 is relieved of the restraint of motor 22 and starts to rotate clockwise at a constant rate of one-twelfth R. P. M. under the influence of the unwinding force of spring motor 19.

Remembering that motor 22 is adapted to drive shaft 16 counterclockwise at one-sixth R. P. M. and that motor 19 is adapted to drive shaft 16 clockwise at one-twelfth R. P. M. it is seen that for the same angular travel cam 36 takes twice the time to move clockwise as counterclockwise. Therefore it is seen that it will take eight and one-half seconds time of clockwise travel (timed power interruption) with load switch S closed for cam 36 to move from the position shown in Fig. 6 for radial edge 112 of cam 36 to move downward sufficiently for the lower edge of cam follower 106 to move thereover under the influence of spring 104.

As soon as gear 29 with cam 36 starts to move clockwise disk 72 moves away from blade 69 which closes switch 60 so that motor 22 can take charge of cam 36 immediately after power is restored. But if the power interruption lasts eight and one-half seconds as above noted cam 36 moves away to allow spring 104 to rotate bell crank 101 counterclockwise about pin 103 until flange 108 strikes screw 109. This is sufiicient movement of bell crank 101 for its lower leg carrying disk 113 to move upward and open switch 85 and for its upper leg to move to the left with cam follower 106 sliding along cam edge 112 and striking roller 82 to rotate latch lever 80 counterclockwise and release drive pin 39 from latch 81 as shown in Fig. 5. When latch 81 releases pin 39, spring 40 moves pin 39 with gear 29 to the clockwise end of slot 38. Therefore should power be restored in eight and one-half seconds it will take the motor 22 one minute to reclose load switch 85 and reapply voltage to the plate circuit of the tube.

Should the power interruption last longer than eight and one-half seconds cam 36 will continue to travel clockwise from the position shown in Fig. 5 an additional time which will be twice as long as the time required when power is restored for motor 22 to return cam 36 to the position shown in Fig. 5. Should the power interruption last for six minutes or more cam 36 will travel counterclockwise until stopped at its cold start position with edge 76 of cam 36 against stop 77.

Having thus recited some of the objects of our invention, illustrated and described one form in which our invention is practiced and explained its operation, we claim:

1. In combination, a cam shaft, means supporting said shaft for rotation between limit positions in either direction, a cam secured on said cam shaft to rotate therewith, a first rotational bias means connected with said shaft continuously to urge said shaft towards rotation at one constant speed in one direction towards one of said limit positions, a second drive means, means for energizing said second drive means continuously to rotate at another constant speed in the other direction, transmission means including a coupling means for coupling said second drive means to said cam shaft when said coupling means is energized to drive said cam in said other direction against the bias of said rotational bias means, said transmission means including a lost motion means between said coupling means and said cam, energizing means for said coupling means, said lost motion means including a first resilient means providing a delay in the effectivity of said second drive means in driving said cam for a fixed time period when said coupling is energized, said transmission means including latch means for said lost motion means to incapacitate said resilient means at the end of said fixed time period, stop means for limiting the rotation of said shaft in said one direction, means for limiting the rotation of said shaft in said other direction by said second drive means, a load switch, operating means operable by said cam at a first selected position while said cam is being driven by said second drive means to close said load switch and at another position while said cam is being driven by said first rotational bias means to open said load switch, said operating means including a second resilient means for unlatching said latch means to restore the effectiveness of said lost motion means when said load switch is opened.

2. The combination of claim 1 in which said lost motion means includes an arcuate slot formed through said cam concentric with said cam shaft and a drive pin parallel to said cam shaft and extending into said slot, said drive pin being rotated about said cam shaft by said second drive means from one end of said slot to the other end of said slot against the bias of said first biasing means when said coupling means is energized.

3. The combination of claim 2 in which said latch means includes a lever pivotally secured to said cam for oscillation in a plane normal to said cam shaft, said lever being formed with a latch hook thereon positionable in the path of said drive pin and means for biasing said latch hook end of said lever towards said drive pin to engage said drive pin when said pin is positioned at the end of said slot towards which it is driven by said second drive means and hold said pin at said end of said slot.

4. The combination of claim 3 in which said operating means for said load switch operable at another position while said cam is being driven by said first rotational bias means to open said load switch includes means associated with said cam at said another position to actuate said latch lever to release said drive pin from said latch hook and allow said first resilient means to rotate said drive pin with respect to said cam to the end of said slot opposite the end in which it was latched.

References Cited in the file of this patent UNITED STATES PATENTS

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