US2916582A - Timing relays - Google Patents

Description

2 Sheets-Sheet 1 A. HUFNAGEL.

TIMING RELAYS Dec. 8, 1959 Filed Sept. le, 1958 INVENTOR. fzdpew Haz/hagel 0- A .Qinfm5' HTTOHN'Y Dec. 8, 1959 A. HUFNAGEL 2,915,582

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HIS TTORNEY United, States Patent Office 2,916,582 Patented Dec. 8, 1959 TIlVIING RELAYS Andrew Hufnagel, Penn Hills Township, Allegheny County, Pa., assign'or to Westinghouse Air Brake Colnpany, Wilmerding, Pa., a corporation of Pennsylvania Application September 16, 1958, Serial No. 761,435

' l,9 claims. (el. zool- 97) My invention'relates to timing relays, and more particularly to relays'of the type comprising a contact which becomes closed at the expiration'of a time interval of relatively long duration after therelay becomes energized. An object of my invention s the provision, in a relay of the foregoing type, of novel means for maintaining constantitheftime required to close the timecontacts irrespective of variations in the source of voltage supplying the'relay and irrespective of variations in the ambient temperature. y Y u In theattainment of the vforegoing object I provide a self-timing relay including an operating coil, an armature operable Vin responser to `the` energization of the operating'coil,`an]oscillating pendulum operatively connected tofthe'armaturea `df'said'pendulum in turn controlling the"'nergi`zati'on lof'the.a rn`1 at ure.,' A timing mechanism actuatedjby th`e"armratu're"movement is effective to close aj Contact afteij'af predetermined time interval.

Otheriobjects andfadvantages of my invention will become apparent 1from' the ffollowfing description and the accompanying drawings in which:

i"Figl isfa sideeleva'tionalview of a relay in accordance with4l y'inlventio'n; y .A n

f' Fig.2"1s'aifront,elevational View of the relay of Fig.` 1; Fig. 3 fis'aplanviewhof the relay of Fig. 1;

Eig. `fifisfani enlarged isometric view of a portion of the armature of the "relay of Fig. 1;and, Fig. 5 is a Aschematic diagram of electric;V circuitry rforfthe relaybf Fig.

' `lshall tfdezscribe yone embodiment of my invention and shallrft en"'vpointy. out thehnovel features thereof in theappended I 'f n f 'Referlringrftofthe drawings, timing relay 11 includes a U-shapedbackstrapf 13 which "receives an electromagnet orstepping.jmagnet,"14. consisting of an operating coil winding 15 mounted on a'central core 17, which core is aixed to backstrapu13 as by a` screw 19. Backstrap13 is'firiturn aflxed 4tofrelay base 21 as by screws 23. An L-shaped armature 25.7is pivotally mounted on pin 24 welded on thefree end of leg`13b of backstrap 13 to permitthe'inner 'angle of thearmature to rock with respectlto leg 13b offbackstrap V13. One leg 25a of `armature' 25 extends transversely across the end of core 17, andthe other leg.25b extends downwardly adjacent leg 13b of backstrap 1,3. Y A depending arm 27 is aixed to leg 255 of armatureZS.

Avhollow rod 29 ismounted on base 2 1 as by bolt 31. As best seen in Fig. 3, a lateral extension 33 mounted on rod 2.9 by `b olt31 retains a coil spring 35 in position to bias armature 25 to' a normally nonattracted or open position,`thatis, with lthe leg-25a separated from the end of core17.' QA`` button 33a formed on the end of extension A3'3, vanda `buttfon27aformed on arm 27 hold spring asY ramadan. j

As best seen in Fig. 4a projection 25e is formed on le`gg25bmof armature 25. One end of a downwardly extendingreedV 28 ofisuitable conductive material isY dis-F a, portion `ofv 'theVw i `planetary.,assembly 53.

posed between a pair of insulative blocks 30 and affixed to projection 25e as by rivets 32. Suitable insulative bushings, not shown, are interposed between rivets 32 and the apertures in reed 28. A weight 34 is secured as by a screw 36 to the lower end of the reed 28. A contact button 36a is welded on the head of screw 36. An electrical lead, indicated schematically in Fig. 5, is connected to reed 28. Reed 28 and weight 34 form a compound pendulum 38 whose oscillating frequency is essentially fixed by factors such as gravity, the mass of the weight 34, the stiffness of reed 28, and the stiiness of the member, here a contact 40a mounted on a spring 40, which contact button 36a engages.

One end of the leaf type contact spring 40, of suitable conductive material, is mounted on a J-shaped back plate 42, see Fig. 3, which plate is in turn mounted between leg 13a of backstrap 1'3 and base 21. Spring 40 is aiiixed to plate 42 as by screws 44 and 46 extending through insulative blocks 48. As best seen in Fig. l, in order to insulate spring 40 from the remainder of the relay, spring 40 is initially axed between insulative blocks 48 by screws 44 and then this assembly is in turn affixed by screws 46, spaced from screws 44, to plate 42. An electrical lead, indicated schematically in Fig. 5, is connected to spring 40.

Spring 40 is formed and mounted to be strongly biased toward reed 28. Contact button 40a on the lower end of spring 40 normally closes or engages Contact 36a when relay 11 is deenergized. The extreme lower end of spring 40 is bent and arranged to engage an L-shaped stop member 50 which is affixed to base 21 by nuts 52. Stop 50 is arranged to position spring 40 approximately parallel to reed 28, that is, stop 50 limits any movement of spring 40 toward reed 28. Stop 50 also limits any excessively large amplitude swings of pendulum 38 toward spring 40, as will be explained hereinbelow.

The details of the gearing assembly are similar to those shown and discussed in Patent No. 1,966,965, issued on July 17, 1934 to B. Lazich and H. E. Ashworth, now expired, and which patent is assigned to the same assignee as the present invention. Therefore, for present purposes, only a brief description of the gearing assembly will sufiice for an understanding of the operation of my relay.

One end of a leaf spring 37 is aflxed as by rivets to the lower end of an arm 27 and a pawl 39 is afxed to the other end of spring 37. Pawl 39 engages a ratchet wheel 41 afiixed on the end of a rotatable shaft 43. A spur gear 45 is affixed on the opposite end of shaft 43, see Fig. 2. A clutch assembly 47 including a clutch wheel 49 and a spur gear wheel 51 is rotatably mounted intermediate the ends of shaft 43. A planetary gear assembly 53 is rotatably mounted on shaft 43 at a point Vbetween clutch assembly 47 and spur gear 45. Spur gear 45 operatively meshes with a spur gear 55 which is affixed on one end of a countershaft 57 of A sun gear 59 afiixed on the opposite end of countershaft 57 engages a gear wheel 51 of clutch assembly 47. Sun gear 59 rotates about wheel 51 when a brake arm 61 is actuated by means, not shown, to drop against or engage wheel 49 of clutch assembly 47 to hold the clutch assembly including gear wheel 51 stationary. An index plate 56 is aflixed to gear assembly 53 and is rotated by the movement of sun gear 59 around wheel 51. Link member 64 carrying a movable timing contact 66 is aixed to plate 56. A timing segment 58 is movably positioned with respect to plate 56 by interval adjusting worm 60 and locked by nut 62. Adjustment by worm 60 of segment 58 with respect to plate 56 determines the initial spacing between the movable contact 66 and a stationary timing contact 68 and thus the time interval between actuation of the brake 61 and the closing of the timing contact 68. When the timing contacts 66 and 68, close, a separate contact, not shown, is opened to cause relay 11k to be` deenergized. When `brake 61 is actuated to disengage clutch wheel 49, planetary assembly 53 returns to its initial position due to gravity in preparation for the next timing operation.

Fig. shows a schematic diagram of a portion of the electrical circuitry of the relay 11. A source of potential here shown as a battery 75 is connected to the operating coil 15 of relay 11 over a circuit which may be traced from the positive terminal `of battery 75, through a suitable energizing switch 77, contact spring 4t) and contact buttons 40a and 36a, reed 28, and coil 15 to the negative terminal of battery 75. A snubbing resistor 79 is connected in parallel with coil 15 to suppress contact arcing and to control the pickup and release time of the relay. As will presently be explained, the energy impalted to pendulum 38 by movement of the armature 25 is substantially constant.

It has been experimentally found that by properly selecting the value of resistor 79` with respect to the impedance of coil 15 a maximum energy can be imparted to the pendulum at a normal operating voltage. Further, a resistor selected for purposes of causing maximum energy to be imparted to the pendulum at normal voltages is also effective, at relatively higher voltages, to limit the amplitude of oscillations of the pendulum. It has thus been found possible to operate the timing relay over a wide range of voltages, in one embodiment from 13 to 32 volts, with the frequency lbeing the same at 'both extremes of voltage and a maximum of 2% higher at some intermediate voltage.

The operation of relay 11 is substantially as follows: When switch 77 is closed, coil 15 will be energized over the circuit previously traced causing armature 25 to move to its attracted position. Movement of armature 25 moves reed 28 aflixed thereto to the right, as oriented in Fig. l, and thus imparts mechanical energy to pedulum 38 causing said pendulum to swing to the right, and thereby to disengage or open the contacts 36a and 40a. Coil 15 is then deenergized and its flux field 'will decay. Armature 25 will then `be returned to its nonattracted position by the force of the biasing spring 35. This second movement of armature 25 imparts additional mechanical energy to pendulum 38 and said pendulum reverses its direction of oscillation and moves to the left toward engagement with spring 49. With contacts 40a and 36a closed, coil 15 will again `be energized and the cycle of operation will be repeated.

The movement of armature 25 between its attracted and nonattracted positions causes arm 27 mounted on the armature to actuate pawl 39 which engages and drives the ratchet wheel 41, shaft li3 and gear 45. When a timing operation is initiated by the actuation of brake 61, clutch wheel 49 is braked and clutch assembly 47 including gear wheel 51 is held stationary. Pinion gear 45 on shaft 43 turns spur gear 55 and causes the countershaft 57 and pinion 59 to rotate. Since gear wheel 51 is stationary, sun gear 59 rotates or climbs around gear wheel 51. The rotation of sun gear 59 causes the planetary assembly 53 including spur gear 55, index plate 56 and llink member 64 to rotate counterclockwise as oriented in Fig. l. Movable timing contact 66 is then moved toward stationary timing contact 68 at a constant predetermined rate. The timing interval is controlled by the initial spacing between contacts 66 and 68 as determined by adjusting 'worm 60. When the timing contacts 64 and 66 close, a separate contact, not shown, deenergizes relay 11 to stop the stepping action. The planetary assembly 53 remains in a position corresponding to the closed position of the timing contacts until brake arm 61 is released, by external means. When brake 61 is released the planetary assembly 53 returns to its initial position under the influence of gravity in readiness to complete a new timing operation.

Pendulum 38 receives energy due to each movement of the armature of relay 11. Initially the amplitude of the swing of pendulum 38 will increase until the energy imparted thereto by armature 25 is equal to the energy dissipated in the pendulum due to mechanical hysteresis, windage, and friction of the Contact buttons 40a and 36a. It will be appreciated that the actual amounts of energy involved are quite small.

The relay coil 15 is energized at a relatively high level, and armature 25 has a stiff biasing spring 35 so that the operating or movement time of the armature is relatively short with respect to the period or time of the pendulum swing. Since the armature 25 operates quickly and with a stroke of fixed length, the mechanical energy imparted to the reed 28 at each stroke is substantially constant irrespective of operating voltage or ambient temperature. Thus the oscillating frequency of pendulum 38 is affected by the stroke and operating time of the armature 25 only to the extent that a relatively small amount of mechanical energy is being imparted to the reed to keep the pendulum swinging. Since the operating frequency of the coil 15 and armature 25 is in turn determined by the pendulum actuated co-ntact 36a actuating cont-act 40a, the frequency of operation of the coil and armature must also remain constant.

Stop 50 lis an included safety factor. Any lessening of friction losses or increase in stroke of the armature might possibly build the amplitude of the pendulum swing to a point of eventually damaging reed 28 or contact spring 40. Stop 50 is therefore added to limit excessive swings of the pendulum 38, but it is located at such a distance that it has only a minor inuence on the normal free swinging characteristics of the pendulum. Stop 50 is nonresilient such that should reed 28 strike the stop enough energy is absorbed to limit the swing of the pendulum 38 in both directions.

While my invention has been described with reference to a particular embodiment thereof, it will be understood that various modifications can be made by those skilled in the art without departing from the invention. The appended claims are therefore intended to cover such modifications within the true spirit and scope of the invention.

Having thus described by invention, what I claim is:

l. A relay including a stepping mechanism for closing a contact after the expiration of a predetermined time interval following the initial energization of said relay comprising, an electromagnet, an armature movable between a biased nonattracted position and `an attracted position in response to the energization of said electromagnet, said armature arranged to actuate said stepping mechanism, an arm carrying a first electrical contact, and a pendulum carrying a second electrical contact, said pendulum being urged to oscillation by the movement of said armature, said pendulum oscillating between engaging and nonengaging positions of said first yand second contacts, whereby said electromagnet is arranged to be periodically energized by a circuit completed through said contacts.

2. In a self-tirning relay having a timing contact which is closed after the expiration of a predetermined time interv-al following the initial energization of said relay, the combination of a stepping magnet including an electrical circuit therefor, an armature movable between an initially biased nonattracted position and an attracted position in response to the energization of said stepping magnet, a resilient contact member in the electrical circuit of said stepping magnet, a pendulum including a resilient arm and an electrical contact, said pendulum being operatively connected to said armature and oscillating at its natural frequency as energy is imparted thereto by movement of said armature, said pendulum and its electrical Contact cooperating with said resilient contact member to control the timing of the energization of said stepping magnet, and means actuated by said armature for closing said timing contact.

3. A timing relay comprising an electromagnet arranged to be energized from a source of potential, an armature operatively connected with said electromagnet and movable from a first to a second position as said electromagnet is energized, a resilient contact member in the electrical circuit of said electromagnet, a pendulum including a resilient arm and carrying an electrical con` tact, said pendulum being operatively connected with said armature and being periodically urged to oscillation at its natural frequency as said armature moves between its said positions, said electrical contact on said pendulum cooperating with said contact member for periodically connecting said electromagnet to its source of potential whereby the natural period of oscillation of said pendulum is unaffected by the operating characteristics of said armature.

4. A timing relay comprising an electromagnet arranged to be energized from a source of potential, an armature operatively connected with said electromagnet and movable from a first to a second position as said electromagnet is energized, a resilient contact member in the electrical circuit of said electromagnet, a pendulum including a resilient arm and carrying an electrical contact, said pendulum being operatively connected with said armature and being periodically urged to oscillation at its natural frequency as said armature moves between its said positions, said electrical contact on said pendulum periodically engaging said contact member for connecting said electromagnet to its source of potential, said resilient arm of said pendulum and said resilient contact member cooperating to dissipate a portion of the oscillation energy of said pendulum to control the amplitude of the oscillations of said pendulum, and a stop member arranged to position said resilient contact member rela` tive to the unoperated position of said pendulum and arranged to limit the amplitude of oscillations of said pendulum.

5. In a self-timing relay having a timing contact which is closed after the expiration of a predetermined time interval which remains constant irrespective of the operating voltage of the relay or ambient temperature, the combination comprising an electromagnet arranged to be energized by a source of potential, an armature operatively connected with said electromagnet and movable relative thereto between an initially biased nonattracted position and an attracted position as said electromagnet is energized, a contact member in the `electrical circuit of said electromagnet, a pendulum including a resilient arm carrying a first contact operatively connected with said armature and oscillating in response to the movement of said armature, said pendulum cooperating with said contact member for completing a circuit for energizing said electromagnet, and means actuated by said armature in moving between its positions for closing said timing contact.

6. In a self-timing relay, the combination comprising an electromagnet arranged to be energized by a source of potential, an armature movable between an initially biased first position and a second position in response to the energization of said electromagnet, an arm carrying a first contact connected in the electrical circuit of said electromagnet, a pendulum including a resilient arm carrying a second electrical contact, said pendulum being operatively connected to said armature and oscillating in response to the movement of said armature, said pendulum cooperating with said arm for completing an energizing circuit for said electromagnet, a timing contact, stepping means operatively connected to said contact and said armature and actuated due to movement of said armature, and said stepping means being effective to close said timing contact after the expiration of a predetermined time interval following the initial energization of said electromagnet.

7. In a self-timing relay the combination of a stepping magnet arranged to be energized by a source of electric potential, an armature movable relative thereto between an initial position and a second position in response to the energization of said stepping magnet, a timing contact, stepping means loperatively connected with said armature and actuated by movement of said armature for engaging said contact after the expiration of a predetermined time interval following the initial energization of said stepping magnet, a first contact carrying member connected in the electrical circuit of said stepping magnet, a pendulum including a resilient arm carrying a second contact operatively connected with said armature and having oscillatory motion in response to movement of said armature and between engaging and nonengaging positions of said first and second contacts, and said pendulum cooperating with said contact member in said engaging position for completing an energizing circuit for said stepping magnet whereby said timing means are stepped for closing said timing contact.

8. In a self-timing relay, the combination of electromagnetic means, an armature movable between an initial position and a second position in response to the energization of said electromagnetic means, a contact member, a pendulum operatively connected to said armature and adapted to cooperate with said contact member, an electrical circuit controlled by said pendulum and said contact member for connecting said electromagnetic means to a source of energy, and stepping means actuated by said armature following the initial energization of said electromagnetic means.

9. In a self-timing relay, the combination of an electromagnet and an armature movable between a nonattracted position and an attracted position in response to the energization of said electromagnet, a spring biasing said armature to said nonattracted position, a pawl operatively connected to said armature and actuated by movement of said armature, a gear train including a rotatable clutch assembly, a planetary gear assembly, means for braking said clutch assembly, said planetary assembly arranged to rotate about said clutch assembly in response to the continued actuation of said gear train when said clutch assembly is braked, timing contacts arranged to be closed by said planetary assembly after said planetary assembly has rotated about said clutch assembly for a predetermined distance following the initial energization of said electromagnet, a pendulum aixed to said armature and arranged to be actuated thereby, said pendulum including a reed having a weight and a first contact secured thereto, a exib-le arm including a second contact, an electrical circuit for energizing said electromagnet being completed through said first and second contacts, said pendulum cooperating with said flexible arm so that said first contact engages said second contact for energizing said electromagnet, and a stop member arranged relative to said exible arm and pendulum for positioning said flexible arm and limiting the amplitude of oscillation of said pendulum.

References Cited in the file of this patent UNITED STATES PATENTS 1,622,044 Miller et al Mar. 22, 1927 1,844,169 Livingston Feb. 9, 1932 1,966,965 Lazich et al July 17, 1934 2,653,200 Foster et al Sept. 22, 1953

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