US2896051A - Relay - Google Patents

Description

July 2l, 1959 o. L. TAYLOR 2,896,051

y RELAY Filed March so, 195e 2 sheets-sheet 1 Owen L. Toylor.

ATTORNEY July 21, 1959 o. TAYLOR 2,896,051

RELAY Filed March so, i956 2 sheets-sheet 2 United States Patent O f' RELAY Owen L. Taylor, Easton, Conn., assignor to The Bryant Electric Company', Bridgeport, Conn., a corporation of Connecticut Application March 30, 1956, Serial No. '575,035

Claims'. (Cl. Zim- 122) This invention relates generally to electrical relays, and more particularly to a relay having two positions at which it will remain after removal of operating force.

For certain applications, such as in the low voltage control of residential lighting, a number of relays are required of relatively small size, and in order to achieve maximum public acceptance they should be low in cost. For example, for residential lighting applications, the relays should be small enough to be accommodated in a standard knockout hole of a standard electrical outlet box, and should be susceptible of ready mounting therein. At the same time, the relays must be low in cost since a relay is needed for each electrical outlet.

One object of this invention, therefore, is to provide a novel, simplified type of relay having two positions to which it may be operated, and having means to maintain it as each position after removal of the operating force.

Another object of this invention is to provide a novel type of thermal operating means for a two position type of relay, which is capable of operating the relay to both of its positions.

Another object of this invention is to provide a novel operating mechanism for a snap action type of switch contact.

Still another object of this invention is to provide a novel relay of the type described, with snap action contacts of the type having two stable positions, with electroresponsive means for operating the contacts to each position.

A particular object of this invention is to provide a relay of the type described having a novel casing structure adapted to be secured in a knockout hole of an outlet box by merely inserting a part of said casing therein.

These and other objects of this invention will become more apparent from consideration of the following detailed description of preferred embodiments thereof, when taken in connection with the attached drawings, in which:

Figure 1 is a front elevational view of a relay constructed in accordance with this invention with parts thereof being shown in section;

Fig. 2 is a side elevational view of the relay shown in Fig. l illustrating the relay contacts thereof;

Fig. 3 is a top view of the relay shown in Fig. l;

Fig. 4 is a transverse sectional view of the relay shown in Figs. l to 3 taken substantially on the line IV-IV of Fig. l;

Fig. 5 is a partial sectional view of the lower supporting member for a relay similar to that shown in Figs. l to 4, but illustrating a modified type of support for the relay operating member;

Fig. 6 is a sectional view of a relay similar to that shown in Figs. l to 4 and an outlet box, but with the relay being greatly reduced in size and embodying a modified form of supporting means for the parts of the relay, and including a casing for the relay; and

Fig. 7 is a schematic illustration of a circuit showing one way in which a relay constructed in accordance with this invention may be utilized.

2,896,051 Patented July 21, 1959 While a relay may be constructed in accordance with this invention in many different forms, the illustrative embodiments of the invention shown on the drawings and hereinafter particularly described, disclose particular forms of the invention which have been evolved for a particular application. Referring first to the form of the invention illustrated in Figs. 1 to 4, a supporting base is provided for the parts of the relay comprising this invention which includes a plate portion 2, and a laterally projecting ledge portion 4, which may be formed integral with the plate portion 2, or separately therefrom, and secured thereto in any desired manner. The supporting base comprising the two portions 2 and 4 should be of an electrical insulating material, such as fiber or a molded insulating material.

The relay contacts are supported on the plate portionv 2 of the supporting base, with one contact being supported on an angular terminal member 6, one leg of which is secured to the plate portion 2 of the base by a securing screw 8 which passes through an opening in the base and is threaded into a threaded opening in the terminal 6. Therterminal 6 is provided with a terminal screw 10 for the purpose of securing an electrical conductor thereto, and the leg of the terminal 6 which projects laterally from the plate portion 2 has a stationary contact 12 secured thereon by any suitable means, such as by welding or the like. The contact 12 is preferably of an arc re sistant electrical conducting material, such as silver or a silver alloy.

The movable contact of the relay is supported on an angularly shaped terminal 14 having one leg secured to the plate portion 2 of the base by a fastening screw 16 in substantially the same manner as terminal 6, and this same leg is also provided with a terminal screw 18, similar to the terminal screw 10 for the terminal 6. A contact blade 20 is adapted to be mounted on the other leg of the terminal 14 by means of a clamping plate 24, and rivets 22 which pass through this leg of the terminal 14, and through the switch blade 20 and the clamping plate 24. The switch blade 20 is preferably of a resilient electrical conducting material, such as a copper alloy, and is formed so as to be operable to open and close the relay contacts with a snap action. For this purpose the switch blade 20 is provided with a generally H-shaped opening 26 (Fig. 3) to form inwardly extending compression legs 28 and 30. The movable contact 32 is mounted on the switch blade 20 adjacent the free end thereof. The contact 32 may be mounted on the switch blade 20 in the same manner that contact 12 is mounted on terminal 6, and may be of the same material.

A generally U-shaped actuating spring 34 is provided for causing the switch blade to open and close the contacts of the relay with a snap action, and this spring may be of any desired resilient material, such, for example, as spring steel. The outer ends of the legs of the actuating spring 34 are curved inwardly and then outwardly as at 36, and are assembled with the switch blade by stressing the legs of the actuating spring 34 towards each other so that the bent portions 36 can have their outer surfaces engaged by the inner ends of thecompression legs 28 and 30, respectively, of the switch blade. The arrangement is such that when the actuating spring 34 engages the compression legs 28 and 30 of the switch blade 20, the actuating spring is under stress and thus exerts a compressive stress on the compression legs 28 and 3Q. In order to define the open circuit position of the relay contacts, an angularly shaped stop member 38 has one leg thereof secured to the plate portion 2 of the base, as by a securing screw 40 which extends through the base and is threaded into a threaded opening in this leg of the stop member 38. The other leg of the stop manner about its points of engagement with the compression legs 28 and 3i), to one side or the other of a central position where the compression legs 2S and 30 are in alignment. Thus, as viewed in Fig. l, the actuating spring 34 has moved in a counterclockwise direction from such a central position so that the compression leg 28 extends beneath the main body of switch blade 20, and the inner end of the compression leg 30 extends above the main body of the switch blade 20. This means that the line of force of the actuating spring 34 is in a direction to move the free end of the switch blade 26 upwardly to cause engagement of the movable contact 32 with the stationary contact 12. This is a stable position of the relay contacts so long as the actuating spring 34 is not permitted to move so'far in a counterclockwise direction that all stress in the spring is relieved. Now by simply moving the actuating spring 34 in a generally pivotal manner in a clockwise direction, it will be observed that the line of action of the free ends of the actuating spring 34 will move over the central position where the compression legs 28 and 30 are in alignment, to a position where the line of action of this spring extends downwardly toward the outer end of the switch blade 20 to cause the movable contact 32 to suddenly move away from the stationary contact 12 and into engagement with the stop member 38 with a snap action, which defines the open circuit position of the relay contacts. This is also a stable position of the contacts so long as the actuating spring 34 is not permitted to go so far in a clockwise direction as would permit relief of all stress in the actuating spring 34. Obviously, movement of the actuating spring in the reverse direction will result in the line of action of the actuating spring moving overcenter in the opposite direction to close the contacts with a snap action.

In order to move the actuating spring 34 in opposite clockwise and counterclockwise directions to operate the relay contacts, there is provided an elongated operating plate 42 which is made of an insulating material, such as ber or a molded insulating material. The operating plate 42 is provided with a central operating projection 43 at its upper end for engaging in a relatively large opening 44 in the bight portion of the operating spring 34. The lower edge of the operating plate 42 is provided with an inwardly extending notch 46 substantially centrally thereof, which has a relatively small spring locating projection 4S at the base of this notch. The notch 46 in the operating plate 42 provides spaced supporting legs 50 at the lower end of the operating plate 42 which are adapted to be loosely received in a groove S2 formed transversely of the ledge portion 4 of the supporting base. An opening 56 is provided in the ledge portion 4 of the supporting base which intersects the groove 52 in substantial alignment with the notch 46 in the lower edge of the operating plate 42 when the plate is mounted in the groove 52. A coil compression spring 54 is adapted to have its upper end received over the projections 48 in the notch 46 of the operating plate 42, and its lower end received in the opening 56 in the ledge portion 4 of the base, where it reacts against the inner end of an adjustable screw 5S threadedly engaged in the opening 56.

The operating plate 42 and its biasingl spring 54 are restrained by expansible wires 60 and 62 at opposite sides of the operating plate 42, respectively. These wires 60 and 62 are of a relatively high resistance electrical conducting material, having, for example, a resistance of several hundred ohms, and a suitable material may be a nickel-chromium alloy, formed into a wire Vhaving a diameter of about 3 mils, but capable of continuously carrying current in the control circuit to which these wires may be connected. The expansible wires 60 and 62 each connect the upper end of the operating plate 42 and a part rigid with the base, as will be described. Each of the wires 60 and 62 is anchored toI identically formed spaced terminal strips 64. There are four of the terminal strips 64 mounted on the ledge portion 4 of the base, with two located at each side of the operating plate 42, and with each terminal strip being secured to the ledge portion 4 of the base with a strip of insulating material 66 interposed between the terminal strips 64 and the ledge portion 4. Each of the terminal strips 64 and its insulating strip 66 is secured in .place by means of a fastening screw 68, which extends through the ledge portion 4 and an opening in the insulating strip 66, to be threadedly engaged in a threaded opening provided in each terminal strip 64. It will be noted that each of the insulating strips 66, which may be of any desired insulating material such, for example, as ber or the like,'projects inwardly beyond the inner end of its associated terminal strip 64, for a purpose to be described. Each of the terminal strips 64 is provided at its outer end with a terminal screw 70 for the purpose of securing an electrical conductor thereto. Each of the terminal strips 64 is also provided with an adjustingscrew 72 which passes through each terminal strip 64 and its associated insulating strip 66 and is threadedly engaged in a threaded opening provided in the ledge portion 4 of the base. The central portion of the upper surface of the ledge portion 4 of the base is recessed, as indicated at 73,' to permit adjustment of the inner end of each termina-l strip and its associated insulating strip 66 toward and away from the ledgeportion 4 of the base. Preferably the'terminal strips 64 should be of a good electrical conducting material which has some resilience, so that the inner end thereof can be moved toward the ledge portion 4 bythe adjusting screw 72, and upon backing` out of the screw it will return to its original position.v By the same token, the insulating strips 66 should be of a material having some exibility, so that the inner ends thereof will be able to` follow the abovementionedmovement of the terminal strips 64.

Considering rst the expansible wire 60, it has one end 74 secured to the terminal 64 remote from plate portion 2 at the right-handside of the relay as viewed in Fig. l, for example, by welding, soldering or the like. The wire then extends beneath the inner end of the correspondinginsulating plate 66 and then upwardly through an opening therein and around an upper projection 76 formed on the upper end of the operating plate 42, and thereafter it 'is reversely bent downwardly through another opening yin the same insulating plate 66, and then upwardly through another opening in this insulating plate 66 to extend around another projection 78 at the upper end of the operating plate 42 to return once more through an' opening in the same insulating plate 66. From this point the wire 6G extends across the space between the two terminals 64 at theV right side of the relay, as viewed in Fig. l, to the innermost terminal 64 where it extends through an opening in the insulating plate 66 of that tcrminal and then up and around another projection 86 at the top of the operating plate 42 from whence it passes down through a second opening in the same insulating plate 66 and the other end S2 of the wire is then brought up and secured to this inner terminal 64. The expansible wire 62 is similarly secured in place and extends in several courses between the terminals 64 at the left-hand side of the relay, as viewed in Fig. l, and the upper end of the operating plate 42. Thus, one end 84 of the wire 62 is secured to the terminal 64 more remote from the plate portion 2 of the base at the. left-hand side of the relay (Fig. l), andv then eX- tends upwardly through theinsulatingplate 66 of that terminal t0 be looped around a projeCtAOL' Sis al the top of the operating plate 42, from whence it returns to extend down through another opening of the insulating plate 66 for this same terminal, and from there extends across the space between this terminal and the terminal closest to the plate portion 2 at the left-hand side of the relay (Fig. l), where it extends upwardly through a rst opening of the insulating plate 66 of this terminal to be looped around another projection 88 at the top of the insulating plate 42 and back down through another opening and up through a third opening in the inner end of this same insulating plate 66 to be looped around still another projection 90 at the top of the operating plate 42, and from there it extends back through an opening in the same insulating plate 66, and the other end 92 of the wire is then brought up to be secured to the innermost terminal 64 at the yleft side of the relay (Fig. 1).

The expansible Wires 60 and 62 may be either mounted in place inthe manner described above with the compression spring 54 stressed, or with the adjusting screw 58 backed out so that no stress will be exerted on the compression spring 54, but in either case the wires should be mounted so that the lengths thereof at each side of the operating plate are substantially equal so that when the compression spring 54 is stressed, for example, byturning in the adjusting screw 58, the wires 60 and 62 will maintain the operating plate 42 at a substantially central vertically extending position as shown in Fig. l of the drawings. This should be the position of the operating plate when both wires 60 and 62 are at the same temperature. This can be easily adjusted when the wires are cold and not subjected to an electric current which would heat them, by the adjusting screws 72, until the operating `plate 42 is substantially at a vertical position, as mentioned above. It will be noted that the operating plate 42 is not at its normal central position as shown in Fig. l, but that it is inclined somewhat to the right, which is the position it will assume when the wire 62 is supplied with electric current suficient to heat and expand the same. It will further be noted, that at this position of the operating plate 42 the contacts are closed, the actuating spring 34 having been moved overcenter in a counterclockwise direction, and it has overtaken the operating projection 43 so that the left-hand side of the opening 44 in the actuating spring 34 is in engagement with the left-hand side of the operating projection 43. Starting at this position, if the wire 62 is deenergized and permitted to cool, the operating plate 42 will return substantially to its normal vertical position, but due to the fact that the opening 44 in the spring 34 is of a considerably greater extent than the thickness of the operating projection 43 it will not move the actuating spring 34 clockwise a sufficient distance to move it overcenter. Movement overcenter will not occur until the wire 60 is energized and heated sufficiently to expand an amount that will cause the compression spring 54 to move the upper end of the operating plate 42 to the left a further amount beyond its normal central position, whereupon the overcenter movement of the actuating spring 34 will occur as previously described, and thus cause the movable contact y32 to assume its open circuit position with a snap action, all as previously described. As soon as the actuating spring 34 moves overcenter, its line of force will not only cause opening of the contacts, but also tends to cause further movement of the actuating spring clockwise until it overtakes the operating projection 43, with the right-hand side of the clearance opening 44 in the spring engaging the right-hand side of the operating projection 43. Again, if wire 60 is then deenergized and permitted to cool, the operating plate 42 will assume its central vertical position, but again, this will not move the actuating spring 34 overcenter due to the lost motion connection of the operating projection 43 and the actuating spring 34. Heating of wire 62 will permit the operating plate to move to the right and move actuating spring 34 overcenter counterclockwise back to the position shown in Fig. l. It will be noted that movement of the operatingplate 42 is caused by the compression spring 54 when one of the wires 60 or 62 is heated and elongates. In order to effect movement of the operating plate 42, the compression spring exerts a force longitudinally of the operating plate, and actual movement `occurs due to the angle of incidence of the wire which is not elongated. Inasmuch as the diameter of the expansible wires is kept quite small the motion in response to heating of the wire is quite rapid, and for the same reason the cooling rateof the Wires is also quite rapid, which tends to rapidly reset the operating plate 42 at its normal central location. Since movement of the operating plate 42 is due-to a difference in length between the expansible wires 60 and 62, it may be operated in opposite directions quite rapidly, because in moving in opposite directions the differential will be maintained as one wire will always be heating up while the other is cooling, so that the actual rate of movement remains relatively constant, Furthermore, since the wires 60 and 62 are on opposite sides of the operating plate 42 and of substantially the same length, ambient temperature has no effect on the normal central position of the operating plate 42.

The modification of the invention illustrated in Fig. 5 of the drawings pertains to a variation in the manner of supporting the operating plate 42, which comprises a plunger 94 sildably mounted in the opening 56 through ledge portion 4 of the base. The plunger 94 has a socket 96 formed in the upper end thereof for receiving the projection 48 in the notch 46 in the lower edge of the operating plate 42, with considerable clearance. The plunger 94 is biased upwardly by a leaf spring 98 which has one end bearing against the lower end of the plunger 94, and has its other end offset therefrom and secured to the ledge portion 4 of the base, as by a rivet 100.

The operation of the particular support for the operating plate 42 illustrated in Fig. 5 results in substantially the same relay operation as the mode of support illustrated in Figs. 1 and 2, the only substantial difference being that no means of adjustment of the spring pressure is provided in the form of support shown in Fig. 5, whereas the compression spring 54 in the form of support shown in Fig. 1 can be adjusted by means of the adjusting screw 58.

Referring to Fig. 6 of the drawings, there is illustrated a portion of an electrical outlet box 102 having an opening 104 in one wall thereof, which may be formed as the result of removing a standard type of knockout plug normally provided in this type of box. These knockout openings 104 are generally circular in form. The relay illustrated in Fig. 6 is provided with a separate base 106 on which the terminal 64, operating plate 42 and wires 60 and 62 are mounted. This supporting base 106 is generally circular in form, and should be of an insulating material, such, for example, as fiber or a molded insulating material. The base 106 is adapted to be mounted in one end of a generally cylindrically shaped housing part 108, which extends for substantially the entire length of the actuating plate 42 and may be made of metal, preferably a metal having some resiliency, such as sheet steel. The base 106 is secured in the left-hand end of the cylindrical housing part 108, as viewed in Fig. 6, in any desired manner, being located by la flange on the base engaging the flanged end 110 of the cylindrical housing part 108. This permits the outer side of the base 106 to project through the reduced opening lformed by the flange end 110 to permit attachment of conductors in a control circuit to terminal screws associated with each of the terminals 64. The cylindrical housing part 108 preferably has longitudinally extending detent ribs 111 formed thereon which may be spaced about the housing part 108 and terminate short of the inner end of the cylindrical housing part 108 where an outwardly extending ange 112 is formed.

The relay contacts in this embodiment of the invention are mounted within a laterally enlarged casing part 114 of insulating material, such as amolded insulating material, and this casing part is assembled to the part 108 in any desired way, for example, as by screws 116 which extend through the flange 112 of the cylindrical casing part 108 to be threadedly engaged in openings provided in the casing part 114. The casing part 114 is provided with suitable openings for conductors 118 which connect vto the electrical outlet which may be mounted in the box 102.

The reason for the particular Way of supporting the relay and the particular casing therefor illustrated in Fig. 6 is to facilitate mounting the assembly in a knockout opening 104 of an outlet box 102. It is believed apparent that such assembly can readily take place by merely inserting the cylindrical housing part 108 into the knockout opening 104 from the interior of the outlet box 102, until the inner wall of the box engages the flangev112 on the housing part 108, at which time the detent ribs 111, which engage the edge portions of the knockout hole 104 during insertion ofthe housing part 108, will slip past these edge portions of the knockout opening and engage over outer edge portions of the knockout opening edge portions, to. securely yet releasably fasten therelay in place in the lknockout opening 104. If it is desired to replace a relay mounted in this manner, it can be readily done by simply withdrawing the cylindrical housing part 108 inwardly from the knockout opening 84, and a new relay mounted in the opening in the same manner described above.

As mentionedat the outset, one application of a relay constructed inaccordance with this invention is in the low voltage control of residential wiring, where these relays maybe mounted in residence outlet boxes in the manner shown in Fig. 6, and described above. In this type of application the relay is connected in circuit'sub stantially as shown in Fig. 7, where the power supply conductors are connected to the primary winding 124 of a transformer having a low voltage secondary winding 126. One illustrative example would be Where the primary voltage is about 115 volts, and the secondary voltage is about volts. One end of the secondary winding 126 may be connected by a conductor 12S to one end of each of the expansible wires 60 and 62 by'rneans of their respective conductors 120. The other side of the low voltage secondary winding 126 may be connected by a conductor 130 to the movable contacts 132 of single pole double throw control switches, each having a pair of stationary contacts 134 and 136. One of the supply conductors is connected to one of the conductors 11S leading to one of the relay contacts 20, while the other supply conductor 122 is connected by means of a conductor 138 to the load and this, in turn, is connected by means of the other conductor 118 to the other contact 12 of the relay.

It is apparent that any desired number of control switches having movable contacts 132 may be provided, with each contact 134 thereof being connected to the conductor 120 leading to the other end of one of the expansible wires 60, and the other contact 136 of each control switch being connected to the other end of the other expansible wire 62 by means of a conductor 120.

As stated above, this permits any desired number of low l snap action, and provides stability in each of these positions. Moreover, the contacts are under the control of an actuator spring 34 which is moved in a generally pivotal manner to cause the above-mentioned snap action movement. Finally, the spring actuator for the contacts is actually moved by an operating plate 42 and its biasing spring under the control of expansible wires 60 and 62. While the movement due to expansion of such wires is relatively small, the particular arrangement permits sufficient movement of the Contact operating spring 34 as to cause the snap action movement of the relay contacts previously referred to. The size of the expansible wires 60 and 62 is kept small to maintain a rapid heating and cooling rate and the arrangement is such that movement is due to the differential expansion of the two expansible wires 60 and 62, so that a rapid back and forth open and closed operation of the relay can occur.

Having particularly described preferred embodiments of this invention as required by the patent statutes, it is desired that the invention be not limited to these particular structures as it will be apparent to persons skilled in the art that many modifications and variations thereof may be made without departing from the broad spirit and scope of this invention. Thus, variations in the supporting base structure have been illustrated herein, as well as supporting structure both`with and without an enclosing casing. Likewise, it is apparent that relays constructed in accordance with this invention may be employed for many uses other than the particular one which has been referred to, namely the low voltage control of residential electrical outlets. Thus, the invention should be interpreted as broadly as consistent With the prior I claim as my invention:

l. A relay comprising, a base of insulating material, separable contacts mounted on said base, an elongated contact operating member having one end supported on said base for longitudinal and pivotal movement, means engaging the other end of said operating member for operating said contacts in response to lateral movement of said other end of the'operating member, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and spring means reacting between said base and said operating member to bias said member longitudinally toward its aforesaid other end to place said wires under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position.

2. A relay comprising, a base of insulating material, separatble contacts mounted on said base, an elongated contact operating member having one end pivotally mounted on a support which is slidably supported on said base for movement in a direction longitudinally of said operating member, means engaging the other end of said operating member for operating said contacts in response to lateral movement of said other end of the operating member, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and spring means reacting between said 4base and said support for biasing said support in a direction longitudinally of said operating member toward its aforesaid other end to place said wires under tension so that when one wire is heated said other end of the operatingmember is moved toward the opposite side by said spring means to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position.

3. A relay comprising, a base of insulating material, separable contacts mounted on said base, an elongated contact operating member having one end mounted on said base for both longitudinal movement away from said base and pivotal movement, means engaging the other end of said operating member for operating said contacts in response to pivotal movement of said operating member about an axis adjacent said base, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, spring means reacting between said base and said support for biasing said operating member longitudinally toward the aforesaid other end of said operating member to place said wires under tension so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire and said spring means to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position, and manually adjustable means engaging said spring means for selectively varying the force exerted thereby.

4. A relay comprising, a base of insulating material, separable contacts mounted on said base, an elongated contact operating member having one end loosely received in a recess formed in said base, means engaging the other end of said operating member for operating said contacts in response to pivotal movement of said operating member about an axis adjacent said base, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and spring means reacting between said base and said operating member for biasing said operating member longitudinally outwardly of said recess to place said wires under tension so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire and said spring means to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position, and means for adjusting the force exerted by said spring means,

5. A relay comprising, a base of insulating material, separable contacts mounted on said base, means including a member movable overcenter for moving one of said contacts with a snap action to and from stable positions where said contacts are open and closed, respectively, an elongated contact operating member having one end movably mounted on said base, a lost motion connection between the other end of said operating member and said contact moving means for operating said contacts in response to pivotal movement of said operating member about an axis adjacent said base and permitting said overcenter member to move beyond the portion to which it is moved by said operating member, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and said wires being under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position.

6. A relay comprising, a base of insulating material, separable contacts mounted on said base, an elongated contact operating member having one end movably mounted on said base, means engaging the other end of said operating member for operating said contacts in response to pivotal movement of said operating member about an axis adjacent said base, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, said wires being under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position, and each of said wires comprising a continuous length of wire wound in multiple loop-s between the base and said' other end of the operating member.

7. A relay comprising, a base of insulating materiaL separable contacts, one of which is mounted at a xed position on said base and the other of which is mounted on one end of a resilient member having its other end mounted on said base, said resilient member having an intermediate, substantially H-shaped cutout portion to provide opposed integral arms extending inwardly from each end, an actuating member having opposed outwardly biased arms pivotally engaging the inner free ends of said integral arms so that generally pivotal movement of said actuating member in opposite directions will cause movement of said integral arms in opposite directions to result in snap movement of a contact mounted on said resilient member to and from two stable positions where said contacts are open and closed, respectively, an elongated operating member having one end movably mounted on said base and its other end engaging said actuating member for operating said contacts in response to pivotal movement of said operating member about an axis adjacent said base, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and said wires being under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position.

8. A relay comprising, a base of insulating material, separable contacts, one of which is mounted at a fixed position on said base and the other of which is mounted on one end of a flexible member having its other end mounted on said base, said flexible member having compression members extending inwardly from each end with at least the inner ends of said compression members being movable relative to each other, an actuating member having opposed outwardly biased arms pivotally engaging the inner free ends of said compression members, so that generally pivotal movement of said actuating member in opposite directions will cause movement of said compression members in opposite directions to result in snap movement of a Contact mounted on said resilient member to and from two stable positions where said contacts are open and closed, respectively, an elongated operating member having one end movably mounted on said base and its other end engaging said actuating memberfor operating said contacts in response to pivotal movement of said operating member about an axis adjacent said base, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and said wires being under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position.

9. A relay comprising, a base of insulating material, separable contacts, one of which is mounted at a fixed position on said base and the other of which is mounted on one end of a flexible member having its other end mounted on said base, said exible member having spaced opposed portions associated with the aforesaid ends of said ilexible member, respectively, so that at least the spaced opposed edges of said portions are movable relative to each other, an actuating member having opposed outwardly biased arms pivotally engaging said opposed 11 l edges of said portions, so that generally pivotal Vmovement of said actuating member in opposite-directions'willcause movement of said opposed portions in opposite directions to result in snap movement of a contact mounted on said resilient member to and from two stable positions where said contacts are open and closed, respectively, an elongated operating member having one end movably mounted on s aid base and its other end engaging said actuating member for operating said contacts in response to pivotal movement of said operating member about an axis adjacent said base, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and said wires being under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position.

10. A relay comprising, a base of insulating material, separable contacts, one of which is mounted at a xed position on said base and the other of which is mounted on one end of a llexible member having its otherend mounted on said base, said flexible member having longitudinally spaced opposed portions associated with the opposite ends of said exible member, respectively, and the spaced opposed edges of said portions being movable in opposite directions relative to each other, an actuating member having opposed outwardly biased arms pivotally engaging said opposed edges of said portions so that generally pivotal movement of said actuaing member in opposite directions will cause the aforesaid movement of said opposed portions to result in snap movement of the contact mounted on said flexible member to and from two stable positions where said contacts are open `and closed, respectively, and pivotally mounted electroresponsive means directly engaging said actuating member to cause generally pivotal movement thereof in opposite directions.

ll. A relay comprising, a base of insulating material, separable contacts, one of which is mounted at a fixed position on said base and the other of which is mounted on one end of a flexible member having its other end mounted on said base, said ilexible member having longitudinally spaced opposed portions associated with the opposite ends of said ilexible member, respectively, and spaced opposed edges of said portions being movable in opposite directions relative to each other, an actuating member having opposed outwardly biased arms pivotally engaging said opposed edges of said portions, so that generally pivotal movement of said actuating member in opposite directions will cause the aforesaid movement of said opposed portions to result in snap movement of the Contact mounted on said llexible member to and from two stable positions where said contacts are4 open and closed, respectively, and pivotally mounted electroresponsive means having a direct lost lmotion connection exible member to and fr m tworstable positions where said contacts are open and closed, respectively, and pivotally mounted electroresponsive means directly engaging said actuating member to cause generally pivotal move ment thereof in opposite directions.

13. A relay comprising, a base of insulating materiaL separable contacts, one of which is mounted at a tixed position on said base and the other of which is mounted on one end of a llexible member having its other end mounted on said base, said liexible member having spaced opposed portions associated with the opposite ends of said flexible member, respectively, so that at least the spaced opposed edges of said portions are movable relative to each other, an actuating member having opposed outwardly biased arms pivotally engaging said opposed edges of said portions, so that generally pivotal movement of said actuating member in opposite directions will cause movement of said opposed portions. in opposite directions to result in snap movement of the contact mounted on said flexible member to and from two stable positions where said contacts are open and closed, respectively, an elongated operating member extending from said actuating member substantially transversely of said flexible member to have its remote end movably mounted on said base and its other end engaging said actuating member for operating said contacts in response to pivotal movement of said operatingl member about an axis adjacent said base, thermally expansible wires connecting said other end of the operating member to said base at opposite sides of said operating member, respectively, and said wires being under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position, and said operating member is moved in the opposite direction when the other wire is heated to move said contacts to another position.

14. A relay comprising, a base of insulating material, separable contacts, one of which is mounted at a xed position on said base and the other of which is mounted on one end of a flexible member having its other end mounted on said base, said flexible member having spaced opposed portions associated with the opposite ends of said ilexible member, respectively, so that at least the spaced opposed edges of said portions are movable relative to each other, an actuating member having opposed outwardly biased arms pivotally engaging said opposed edges of said portions, so that generally pivotal movement of said actuating member in opposite directions with said actuating member to cause generally pivotal opposed outwardly biased arms pivotally engaging the inner free ends of said integral arms, said integral arms being movable in opposite directions relative to one another lso that generally pivotal movement of said actuating member in opposite directions will cause movement of said integral arms in the aforesaid manner to result in snap movement of the contact mounted on said will cause movement of said opposed portions in opposite directions to result in snap movement of a contact mounted on said flexible member to and from two stable positions where said contacts are open and closed, respectively, an elongated operating member extending from said actuating member substantially transversely of said flexible member to have its remote end movably mounted on said base and its other end engaging said actuating member for operating said contacts in response to pivotal movement of said operating member about an axisadjacent said base, thermally expansible wires connecting said other end of the operating ,member to said base at opposite sides of said operating member, respectively, and said Wires being under tension when cool so that when one wire is heated said other end of the operating member is moved toward the opposite side by the tension in the other wire to operate said contacts to one position, and said operating member is moved in the opposite direction when the other Wire is heated to move said contacts to another position, a casing for said relay comprising a generally cylindrical part enclosing said operating member and expansible wires, and a transverse casing part at one end of said cylindrical part enclosing said contacts, and said cylindrical casing part having a detent portion formed thereon adjacent said transverse casing part for cooperation with the edge of a circular 13 mounting opening of a size to just receive said cylindrical casing part to secure the relay in such an opening.

15. A relay comprising, a base of insulating material, separable contacts, one of which is mounted at a xed position on said base and the other of which is mounted on one end of a exible member having its other end mounted on said base, said llexible member having a pair of longitudinally spaced opposed portions associated with the opposite ends of said ilexible member, respectively, and the spaced opposed edges of said portions being movable in opposite directions relative to each other, an actuating member having opposed outwardly biased arms pivotally engaging said opposed edges of said portions, so that generally pivotal movement of said actuating member in opposite directions will cause the aforesaid movement of said opposed portions to result in snap movement of a contact mounted on said resilient member to and from two stable positions where said contacts are open and closed, respectively, and operating means pivotally and movably mounted on said base and directly engaging said actuating member for operating said actuating member to cause generally pivotal movement of the latter in opposite directions.

References Cited in the le of this patent UNITED STATES PATENTS 1,773,708 Whittingham Aug. 19, 1930 1,868,500 Hanel July 26, 1932 2,076,275 Jorgenson Apr. 6, 1937 2,256,499 Schmidinger Sept. 23, 1941 2,308,522 Leuthold Jan. 19, 1943 2,340,877 Hausler Feb. 8, 1944 2,387,089 Peterson et al Oct. 16, 1945 2,429,074 Rugh Oct. 14, 1947 2,547,999 Brockway Apr. 10, 1951 2,558,219 Kohl June 26, 1951 2,595,967 McCloy May 6, 1952 2,689,283 Pulvari Sept. 14 1954 2,747,052 Blume May 22, 1956 2,811,603 Koch et al. Oct. 29, 1957

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