US3004121A

US3004121A - Electrical relay

Info

Publication number: US3004121A
Application number: US760161A
Authority: US
Inventors: Rolland M Purdy
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1958-09-10
Filing date: 1958-09-10
Publication date: 1961-10-10
Anticipated expiration: 1978-10-10
Also published as: FR1234634A; GB889544A

Description

Filed Sept. 10, 1958 INVENTOR.

ROLLAND M. PURDY ATTO NEYS Unite This invention relates to an improved electrical switch and to a relay incorporating such switch.

The invention has among its objects the provision of a novel electrical switch of simple rugged construction.

A further object of the invention resides in the provision of an electrical switch which successfully stands high temperatures and which may be subjected to high accelerations without fortuitously opening a closed circuit or closing an open circuit.

Yet another object of the invention lies in the provision of a relay of novel construction, such relay incorporating a plurality of switch cont-act sets made in accordance with the invention, and operating such contact sets simultaneously. The above and further objects and novel features of the invention will more fully appear from the following description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are forthe purpose of illustration only and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is a view in vertical section through a preferred embodiment of relay made in accordance with the invention, the switch parts being shown in the position they assume when the solenoid of the relay is deenergized, certain of the parts being shown in elevation, the section being taken substantially along line 1-1 of FIG. 3;

FIG. 2 is a fragmentary view in vertical section of a central portion of the switch of FIG. 1 on an enlarged scale, the parts of the switch being shown in the position they assume when the solenoid of the relay is energized;

FIG. 3 is a plan view of the relay;

FIG. 4 is a fragmentary view in vertical section on an enlarged scale showing the right hand set of contacts as they are shown in FIG. 1, the section being taken generally along line 4-4 of FIG. 3; and

FIG. 5 is a view in horizontal section through the relay, the section being taken generally along line 5-5 of FIG. 1.

The relay of the invention, and the switch portion thereof, may be used to advantage in aircraft missiles and rockets wherein it may be subjected to high accelerations and to at least moderately elevated temperatures;

One specification for a relay for missile and rocket use above specification and has numerous additional advantages such as simplicity, compactness, and ruggedness of construction. I

Turning now to the drawings, the relay shown in FIG. 1 is designated generally by the reference character 10. The relay includes a multi-contact, double-throw, switch, generally designated 11, and a solenoid, generally designated 12, for operating the switch. The relay has a cupshaped housing 14, made of magnetic metal such as iron,

States Patent "ice the housing containing a solenoid coil 15 having a central magnetic core 16 attached centrally to the enclosed bottom of housing 14, as shown. An annular metal member 17 snugly fitting within housing 14 above coil 15 constitutes a first, outer pole piece of the solenoid. An enlarged metal head member 18, secured to theupper end of core 16, and spaced inwardly of member 17 constitutes a second, inner pole piece of the solenoid.

Pole pieces

17 and 18 are separated by an annular gap which is enlarged at four equally spaced zones to form recesses 52 receiving the lower ends of stems 39, to be described. An annular spacing sleeve 21 is positioned within the upper end of housing 14, and rests upon the outer pole piece 17 so as accurately to position the switch assembly with relation to the pole piece of the solenoid.

The switch assembly has an outer metal rim 19 which fits accurately within the upper end of'housing 14 and rests upon spacing ring 21. Metal ring 19 serves to support an insulating plate 20 on which the various contacts of the switch are mounted. Plate 20 may be made of sintered glass, the metal rim 19 and the various contacts and their supporting posts being held in a suitable jig while the glass to form plate 20 is deposited and sintered in the rim 19 and about the posts, As shown, the upper outer edge of metal rim 19 may be slightly relieved so that after the contact mounting plate has been assembled in the housing it may be permanently secured thereto as by edge welding at zone 22. The relay may be provided with a mounting flange secured thereto, as shown in FIG. 1, such flange having cars 24 by which it may be secured to a mounting member such as a panel. Coil 15 of the bered posts or terminals projecting through and sealed to plate 20, as shown in FIG. 3.

The embodiment of switch 11 shown has four similar contact sets spaced equally about the vertical axis of the relay. Two such contact sets are indicated in' FIG. 1, wherein the parts thereof are designated by the same reference characters. As shown each set has two

upper contacts

27, 29 which are mounted upon and electrically connected to

posts

30 and 31, respectively, which project through and are sealed to plate 20. Each contact set has two lower contacts of which one is shown in FIG. 1. The construction of the lower contacts and their relation to the upper contacts in each set will be more readily understood upon consideration of FIG. 4. Opposed

lower contacts

32 and 34, project inwardly from mounting

posts

35 and 36, respectively, and are angularly displaced from the upper contacts of each set so as to provide adequate spacing between the mounting posts for the various contacts. The spacing of the

posts

30, 31, 35, and 36 will be more readily apparent upon consideration of FIG. 3.

The operative confronting portions of the upper and lower contacts of each set lie generally at the same distance from the vertical axis of each Contact set. Vertically movable between the upper and lower contacts of each contact set is a circular disc contactor 37 which is reciprocable along a central axial mounting stem 39 which is secured to insulating plate 20. Thus contactor 37 is electrically insulated from the chassis of the switch.

Disposed about stem 39 and interposed between movable contactor 37 andplate 20 is a first coil compression spring 40 which constantly urges contactor 37 downwardly toward engagement with lower contacts 32 and34. Each spring 40 is overcome, however, when the coil 15 of the solenoid is deenergized, by a second stronger coil compression spring 41 disposed about each stem 39 and acting between a head 42 on the lower end of the stem 39 and the contactor 37. The upper end of spring 41 abuts an electrically insulating sleeve 44, made, for example,

of fiber, disposed about stem 39. A metal washer 45 having for example four equally spaced sequentially oppositely disposed shallow bends therein is interposed between the upper end of bushing 44 and the lower surface of contactor 37, whereby to provide a limited rocking engagement between the bushing and the contactor.

The coil compression spring 40 is of such strength relative to the mass of contactor 37 that when, in effect, the action of spring 41 is removed from the contactor the contactor is held firmly and in engagement with

lower contacts

32 and 34 despite subjection of the relay to high accelerations. In order selectively to remove the action of spring 41 from the contactor 37, thus to close the lower pairs of contacts of all the sets thereof, there is provided a solenoid plunger 46 in the form of a thin ferro-magnetic disc which has four equally spaced holes 48 through which the stems 39 and bushings 44 extend, disc 46 being supported on flanges 47 at the lower end of each of bushings 44. The diameter of each hole 48 somewhat exceeds the diameter of the body of each bushing 44, so as to provide limited freedom of rocking movement of disc 46' relative to the bushings.

When solenoid coil 15 is deenergized, the parts occupy the position indicated in FIGS. 1 and 4, the springs 41 of each of the contact sets holding the respective contactors 37 in elevated position. The strength of each of coil springs ill is such that in such position it not only overcomes its respective spring 40 but maintains

parts

44, 45, and 37 in elevated position in spite of the subjection of the relay to high accelerations. When however, solenoid coil 15 is energized, solenoid plunger disc 46 is drawn downwardly, simultaneously depressing each of the sleeves 44 and permitting springs 40 to advance the contactors to their lower positions. The relatively loose mounting of disc 46 on bushings 44 permits the disc to assume a position in which it transmits substantially equal and simultaneous thrusts to each of bushings 44. Accordingly, upon energization or" the solenoid, all contactors 37 move to their lower positions at substantially the same time. Upon deenergization of the solenoid, each of the substantially identical springs 41 insures the return of its contactor 37 to the upper position at substantially the same instant.

A vertically disposed pin 49 extends through and is secured at a central hole through disc 46. Pin 49 has an enlarged, upwardly converging, frusto-conical head 54 above the disc. Centrally disposed on plate 20 is a depending, downwardly open sleeve member 50 having its lower annular edge inclined parallel to the frusto-conical surface of head 54. The parts are so arranged that the lower edge of sleeve 50 engages and centers head 54, and thus plunger disc 46, when the solenoid coil is deenergized.

The plunger disc 46 is raised to the position of FIG. 1, when the solenoid coil is deenergized, by a coil compression spring 56 the upper end of which is telescoped over the depending pilot portion 55 of pin 49. The lower'end of spring 56 abuts the bottom of a central hole 53 in the inner pole piece 1 8 of the solenoid.

Engagement between

members

50 and 54, when the disc 46 is in its elevated position, centers the disc and prevents its misalignment when the relay is subjected to severe sidewise accelerations. In its lower position, when the solenoid coil is energized, the plunger disc 46 of the illustrative embodiment of relay contacts and is firmly held by the

pole pieces

17 and 18 of the solenoid.

in the embodiment shown, the interior of the relay is exhausted, and may be filled with inert gas, if desired, through a tube 57 the lower end of which extends through and is seal d to plate 29 and into sleeve 56, as shown. After air has been exhausted from the interior of the relay through the tube 57, inert gas may be introduced therethrough, following-which the outer end of the tube may be pinched together and soldered or welded.

Although only a limited number of embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing specification, it is to be expressly understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may be made therein without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

1. An electrical switch having opposed contacts, a post mounted between said contacts, a contactor slidably mounted on said post and selectively movable in opposite directions between said contacts into terminal positions in engagement therewith, a first weaker coil compression spring disposed about said post urging the contactor in a first of said opposite directions, a second stronger coil compression spring disposed about said post urging the contactor in a second of said opposite directions, the second spring normally overcoming the first spring, reciprocable contactor operating means selectively operable at least partially to suppress the action of the second spring on the movable contactor so that the first spring may then move the contactor in the first direction to its respective terminal position, said last mentioned means comprising a bushing slidably mounted on the post and interposed between the inner end of the second, stronger spring and the respective contactor, said bushing having an abutment thereon forming pant of a lost motion connection between it and said contactor operating means, said lost motion connection permitting the contactor operating means to move freely an appreciable distance in said first direction before it retracts the bushing in said first direction.

2. An electrical switch as claimed in claim 1, comprising means coacting with the contactor operating means to stop its movement in the second direction free from operative contact with the abutment means on said bushing.

3. An electrical switch as claimed in claim 2, comprising a plurality of additional posts mounted parallel to said one post and spaced appreciably laterally therefrom, and wherein said contactor operating means is a disc mounted on said one and said additional posts for reciprocation therealong.

4. An electrical switch as claimed in claim 3, comprising a solenoid having a coil and opposed poles, and wherein the contact operating disc coacts with the solenoid poles as a solenoid plunger.

5. An electrical switch as claimed in claim 4, wherein the solenoid coil is elongated, said solenoid poles are positioned at one end of the coil, one of the poles is positioned centrally of the coil, the other of the poles is an nular and is disposed coaxially around and spaced from said central pole, and said contactor operating disc is located coaxially of and close to said poles for movement toward and away from said poles as the solenoid coil is energized and deenergized, respectively.

6. A multi-contact double throw electrical relay including a solenoid having a coil, a plurality of sets of contacts each comprising opposed pairs of contacts, the contacts of each pair being transversely aligned, said sets of contacts beingspaced over the transverse area of the solenoid, each set of contacts having a contactor selectively movable in opposite directions between the opposed contacts thereof, first, weaker resilient means urging each contactor in a first of said opposite directions, second, stronger resilient means urging each contactor in a second of said opposite directions, each of said second resilient means normally overcoming each of the first resilient means, a solenoid plunger mounted to reciprocate relative to the solenoid coil, and means connecting the solenoid plunger to each of the second resilient means so that when the solenoid coil is energized the action of each of the second resilient means is at least partially suppressed so that each of the first resilient means may then move its respective contactor in the first direction to its respective terminal position.

7, A multi-circuit double throw electrical switch ineluding a plurality of similar sets of contacts each comprising opposed pairs of contacts, the contacts of each pair being transversely aligned, said sets of contacts being compactly grouped and spaced over a relatively small area, each set of contacts having operatively associated therewith a contactor selectively movable in opposite directions between the opposed contacts thereof, first, weaker resilient means urging the contactor in a first of said opposite directions, second, stronger resilient means urging the contactor in a second of said opposite directions, said second resilient means normally overcoming the first resilient means, contactor operating means reciprocable in said first and second directions, and means operatively connecting the last named means to each of the second resilient means so that when the contact operating means is moved in said second direction it at least partially suppresses the action of each of the second resilient means so that each of the first resilient means may then move the contactor as sociated therewith in the first direction to its respective terminal position.

8. An electrical switch as set forth in claim 7, comprising a post mounted between the contacts of each set and extending in said first and second direction, and wherein each of said contactors are washer-like members slidably mounted on the respective posts, a bushing slidably mounted on the post of each contact set and interposed between the inner end of each second spring and the contactor operatively associated therewith, each bushing having an abutment thereon forming part of a lost motion connection between it and the contactor operating means, said lost motion connection permitting the contactor operating means to move freely an appreciable distance in said first direction before it retracts the bushings in said first direction.

9. An electrical switch as claimed in claim 7 comprising means for mounting said contactor operating means wherein the same may move freely an appreci' 6 able distance in said first direction before it suppresses the action of each of the second resilient means.

10. An' electrical switch as claimed in claim 8 comprising means co-acting with the contactor operating means to stop its movement in the second direction free from operative contact with the abutment means on said bushings.

11. An electrical switch as claimed in claim 10 comprising resilient means for constantly urging said contactor operating means in the second direction.

12. An electrical switch as claimed in claim it) comprising means to center said contactor operating means at its terminus after travel in said second direction.

13. An electrical switch having opposed contacts, a post mounted between the contacts, a contactor slidably mounted on said post, a first weaker resilient means urging the contactor into engagement with said contacts, a second stronger resilient means urging the contactor away from said contacts, the second resilient means normally overcoming the first resilient means, reciprocable contactor operating means selectively operable at least partially to suppress the action of the second resilient means on the movable contactor so that the first resilient means may then move the contactor into engagement with the contacts, and means for mounting said contactor operating means wherein the same may move freely an appreciable distance away from said contacts before it suppresse the action of said second resilient means.

References Cited in the file of this patent UNITED STATES PATENTS