US2884503A - Coupling device for multi-spring snap action electric switches - Google Patents

Description

April 1959 E. c. CONNELLY 2,884,503

COUPLING DEVICE FOR MULTI-SPRING SNAP ACTION ELECTRIC SWITCHES Filed Jan. 21, 1958 II ulnar-f 1 27 INVENT OR.

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United. States Patent COUPLING DEVICE FOR MULTI-SPRING SNAP ACTION ELECTRIC SWITCHES Eugene C. Connolly, Chicago, IlL, assi or to Electro- Snap Switch & Mtg. (10., Chicago, ll a corporation of Illinois Application January 21, 1958, Serial No. 710,262

7 Claims. (Cl. 200-172) This invention relates to snap action electric switches having a plurality of bridging contact springs operated simultaneously by a single operating button and has for a principal object the provision of a new and improved switch of this type. I

It is a main object of the invention to provide a new and improved coupling device for connecting the operating button of an electric switch to the spring link assembly, by which the plurality of contact carrying springsof the switch are operated by an operation of the operating button.

Another object of the invention is to provide a coupling device which insures positive drive action between the operating button and spring link assembly of a multispring snap action electric switch.

Another object of the invention is to provide a coupling device which can be manufactured and assembled at low cost without sacrificing quality.

Further objects of the invention not specifically mentionedhere will be apparent from the detailed description and claims which follow, reference being had'to the accompanying drawings in which a preferred embodiment of the invention is shown by way of example and in which:

Fig. 1 is a side elevational view of a switch embodying the invention, drawn to an enlarged scale;

Fig. 2 is a front elevational view of the switch of Fig. 1, with the cover removed from the casing;

Fig. 3 is an exploded view in perspective of the yoke and part of the spring link assembly of the switch;

Fig. 4 is a rear elevational view of the operating button; and

Fig. 5 is a side view, partly in section, of the operating button, yoke and spring link assembly of the switch.

Multi-spring electric switches of the snap action type are usually encased in a casing composed of an insulating material and from which casing an operating button is projected. Within the casing, contact carrying bridging springsare connected together by a spring link assembly which mechanically couples together the compression tongues of the springs while maintaining the same electrically independent each of the other.

In prior art switches of this type, of which I am aware, the operating button has been connected to the spring link assembly by means of a pin carried by the button and projecting through a slot in a metallic end member of the assembly which projects into a cavity in the button. In other instances, a plungerlike head on the end of the link assembly is projected into a cavity in the button and a spring made to bear against the plunger to cause movement of the button to move the spring link assembly.

The present invention provides a new and improved arrangement for coupling the operating button of a switch or this type to the spring link assembly thcreof. In its preferred form the coupling device of the present inventionconsists of a metallic yoke fixed in a cavity in the 31110011. projecting from the button-and eontaining-perfora- 2,884,503 Patented Apr. 28; 1959 "ice tions through which a metal end piece on the spring link assembly is projected, that end piece containing slots into which the yoke projects to secure the yoke to the link assembly. Through this arrangement a positive drive con- 5 nection is established between the operating button of the switch and the spring link assembly by which the bridging springs of the switch are moved to overcenter position. This positive drive insures that after slack has been taken up, each increment or movement of the operating button produces a like increment of movement of the link assembly, thereby permitting more accurate adjustment of the switch with respect to the position-of the operating tton at the momentgthe bridging springs overccnter.

a panying drawings in which in Figs. 1 and 2- a multi-spn snap action switch of known design is shown, this switch consisting of a casing 1 composed of an insulating material and having within it two or more transverse cavities 2, in'each of which contact bridging spring 3 is located. The casing also contains a cavity 5 in which the spring link assembly 6 is positioned and contains a perforation 7 through which the operating button 8 projects. In the switch shown by way of example, there are three bridging springs 3, each of which is of known construction having outer tension arms connected together at their ends by contact carrying end portions, from which end portions centrally located compression tongues extendtowards the center of the spring.

As will be seen in Figs. 3, 4 ands, the coupling device of the present invention consists of a yoke 10 having an endwall 11 that contains a rectangular slot 12. Generally rectangular arms 13 project from the sides ofthe end wall 11 andcontain near, their outer ends cars 14 bent out of the arms 13, and increasing the effective thickness of these arms.

The spring link assembly 6, which is of known design, consists of insulating members 15 which in a 3-spring switch are two in number, connected together by a mew tallic member 16 that contains a perforation 17 into which the compression tongues of the central bridging spring are projected. The link also contains a similarend member 18 and a second end member 19, to which'latter member the present invention particularly relates.

As will be seen in Figs. 3 and 5, the end member 19 contains a tonguelike portionZt), a perforation 21 into which the compression tongues of one of the bridging springs lit, and rectangular slots 22 opening into the edges of the member. The inner ends of the slots 22 define between them a neck portion 23 having width transversely of the member 19 slightly less than the width of the slot 12 in the yoke.

As will be seen in Fig. 5, coil spring 24 encircles the insulating member 15 adjacent the end piece 19.

as In assembling the link onto the yoke, end piece 19 is inserted through the rectangular slot 12 and then turned through 90' to position the portions of the end wall 11 of the yoke alongside of the slot 12 into the slots 22 in the member 19. The coil spring 24 is thus abutted 60 against the end wall 11 of the yoke.

AswillbeseenbestinFigs.4and5,theoperating button8 eontainsa rearfacezs into whichopeos acavity having a central portion 26 and transversely disposed end portions 27. the cavity being generally I-shape in cross section. 'lhebuttouflisprovidedwithflangesflwhlch transverselydisposed slots 27 andtheendportionztlof theeudpieceflrc'gisteredwithflrecsntralportlon 26 of the cavity. The central portion 26 of the cavity has invention will be bestunderstood by reference to" width greater than the thickness of the tongue portion 20 of the end piece 19, with the result that the tongue loosely fits into the cavity. The transversely disposed end portions 27 of the cavity have thickness less than the effective thickness of the arms 13 produced by the outwardly extending cars 14, and as a result these arms 13 must be forced into the cavity portions 27 and the cars 14 thereby moved towards alignment with the arms 13 out of which they project. Yoke being composed of half hard material, the arms 13 and cars 14 exert considerable pressure on the walls of the cavities 27. This arrangement securely attaches the yoke to the button.

While the width of portion 26 of the cavity in the button is greater than the thickness of the tongue 20, it is not suliicient to permit rotation of the tongue. Thus when the tongue is positioned in the cavity 26, rotation of the button and yoke with respect to the spring link assembly is definitely prevented. This insures that the portions of the yoke projecting into slots 22 will remain therein and the yoke will remain attached to the spring link assembly.

It will be noted that the depth of the cavity in the button is less than the length of the arms 13 of the yoke, with the result that when the yoke is fully installed in the button cavity with the ends of the yoke abutting against the inner end of the cavity, the end wall 11 of the yoke will be spaced from and substantially parallel to the rear face 25 of the button. It will also be noted that the perforation 21 in the end piece 19 is disposed between the end wall 11 of the yoke and the-rear face 25 of the button.

After the yoke has thus been assembled on the spring link assembly and attached to the button, the bridging springs 3 are attached thereto, each with its compres sion tongues registered with one of the perforations such as .17 or 21 in the metallic portions of the link. It will be noted that the casing 1 contains shoulders 9 that project into the cavity 5 of the casing. When the springs, the link, yoke and button are inserted in the casing, the end of the coil spring 24 remote from the yoke is abutted against the ears 9 and the spring is compressed thcreby to urge the button 8 outwardly of the casing thereby to maintain the flanges 28 on the button in engagement with the casing walls. Preferably the button 8 and the perforation 7 are of rectangular shape and rotation of the moving parts'of the switch with respect to the casing is prevented by engagement of thesides of the button with the edges of the perforation.

Assembly of the switch is completed by registering the cover 1A with the casing 1 and securing it thereon.

To operate the switch, operating button 8 is moved inwardly of the casing thereby to move the end wall 11 of the yoke into engagement with the sides of the slots 22, in the end piece 19, that are remote from the button. Further movement of the button inwardly of the casing moves the link assembly 6 through-the positive drive connection established by the en of the rear wall 11 of the yoke with the edges of the slots 22. This movement continues until the springs over-center, thereby to move the contacts carried by these springs from their normally closed to their respective normally open stationary contacts.

If it is desired to provide for sinnlltaneous action of the plurality of bridging springs 3 of the switch, slots 22aremadewideraxiallyofthecpringlinkbly thanthethicknessoftherear'walllloftheyoke. 'lhroughthisamngemenaaseoonasoneofthebridging spring! 3 overcenters, the spring link assembly moves aheadofthe yokeandthe remainingbridglngsprings 3 are thereby overcentered and simultaneous actionis achieved. Inlnsta'nceswheresimultancous actionisnot desired,-thewidthoftheslots zzisnarrowedtolliahtly morethanthe thickness oftherearwalllloftheyoke andnosuchfreemovement ofthcspringlink assembly results.

When operating pressure is removed from. the button 8, spring 24 bearing against the wall 11 of the yoke 10, moves that wall into engagement with the edges of slots 22 adjacent the button, then moves the spring link 6 and the button 8 to normal positions, with the flanges 28 on the button engaging the walls of the casing. Springs 3 are overcentered by this movement returning the contacts carried thereby to their respective normally closed stationary contacts.

From the foregoing, it will be apparent that the coupling device of the present invention possesses many advantages. It is of simple construction and can be assembled easily, at low cost, without sacrificing quality. Should occasion arise, the coupling device can be disassembled easily and without mutilation or destruction of any of the switch parts.

While I have chosen to illustrate my invention by showing and describing a preferred embodiment thereof, I have done so by way of example only, as there are many modifications and adaptations which can be made by one skilled in the art within the teachings of the invention.

Having thus complied with the statutes and shown and described a preferred embodiment of my invention, what I consider new and desire to have protected by Letters Patent is pointed out in the appended claims.

What I claim is:

1. In a multi-spring electric snap switch, a spring link assembly; an operating button having a rear face into which a cavity of I section opens; a metal member projecting from the end of the spring link assembly and projecting into the central portion of the cavity in the button, said metal member having slots opening into its opposite edges; and a U-shaped metal yoke the closed end of which contains a slot through which said metal member projects, said closed end projecting into the slots in said metal member and the arms of said yoke extending into the transversely disposed end portions of said cavity thereby to connect the button to the link assembly.

2. In a multi-spring electric snap switch: a spring link assembly; an operating button having a flat rear face into which a cavity of I section opens; a flat metal member projecting from the end of the spring link assembly and projecting loosely into the central portion of the cavity in the button, said metal member having slots opening into its opposite edges; a metal yoke having an end wall containing a rectangular slot through which said flat member projects, the portions of said end wall adjacent said slot projecting into the slots in said flat metal member to attach the yoke to the spring link assembly; and parallel arms on said yoke extending at right angles from the ends of said end wall and into the transversely disposed end portions of said cavity to attach the button to the yoke.

3. In a multi-spring electric snap switch, a spring link assembly; an operating button having a rear face into which a cavity of I section opens; a flat metal member projecting from the end of the spring link assembly and projecting loosely into the central portion of the cavity in the button, said metal member having slots opening into its opposite edges; 0. metal yoke having anendwallcontainingarectangularslotthroughwhich said flat member projects, the portions of said end wall adjacent said slot projecting into the slots in said flat metal member to attach the yoke to the spring link assembly; parallel arms on said yoke extending at right angles from the ends of said end wall and into the transversely disposed end portions of said cavity; and cars extending outwardly of said arms and frlctlonally portionsofthebuttondefiningtheeavityto secure the button on the yoke.

4. In a mold-spring electric snap switch, a spring linkassemblmanoperatingbuttonhavingaflatrear face rntowhlehncavltyoflsectionopensraflatmetal member projecting from the end of the spring link assembly and projecting loosely into the central portion of the cavity in the button, said metal member having rectangular slots opening into its opposite edges the inner ends of which slots defining a neck portion of the member; a metal yoke having an end wall containing a rectangular slot through which said neck portion projects, with the portions of said wall alongside said rectangular slot disposed in said slots to attach the yoke to the spring link assembly; and parallel arms on said yoke extending at right angles from the end of said end wall and into transversely disposed end portions of said cavity to attach the button to the yoke.

5. In a multi-spring electric snap switch, a spring link assembly; an operating button having a flat rear face into which a cavity of I section opens; a flat metal member projecting from the end of the spring link assembly and extending loosely into the central portion of said cavity, said metal member having slots opening into its opposite edges; a metal yoke having a flat end wall containing a rectangular slot through which said flat member projects with the portions of the end wall alongside said slot extending into the slots in the metal member; rectangular parallel arms projecting from the ends of said end wall at right angles thereto, the faces of said arms being disposed at right angles to the faces of said flat metal member, said arms extending into the transversely disposed end portions of said cavity to attach the button to the yoke, with said flat end wall disposed parallel to and spaced from said flat rear face on the button.

6. In a multi-spring electric snap switch, a spring link assembly; an operating button having a flat rear face into which a cavity of I section opens; a flat metal member projecting from the end of the spring link assembly and projecting loosely into the central portion of the cavity in the button, said metal member having slots opening into its opposite edges; a metal yoke having an end wall containing a rectangular slot through which said flat member projects, the portions of said end wall adjacent said slot projecting into the slots in said flat metal member to attach the yoke to the spring link assembly; parallel arms on said yoke extending at right angles from the ends of said end wall and into the transversely disposed end portions of said cavity; ears extending outwardly of said arms and frictionally engaging portions of the button defining the cavity to secure the button on the yoke; a casing for said switch, there being a cavity in said casing and a perforation therein aligned with said cavity, said spring link assembly being disposed in said cavity and said button projecting out of the cavity through said perforation; flanges projecting laterally from said button and engaging said casing adjacent said perforation; shoulders in said cavity facing said perforation; and a spring encircling said spring link assembly and abutting against said shoulders and the yoke to yieldingly hold said flanges against the casing.

7. A device for coupling an operating button to the spring link assembly of a multi-spring electric switch comprising: a metallic yoke of generally U-shape having a perforation in its closed end; a flat end member on said spring link assembly projecting through said perforation, said end member containing slots opening into its edges, into which slots portions of the closed end of the yoke project to attach the yoke to the assembly; said button containing a cavity into which the end member projects, the walls of said cavity preventing rotation of the end member with respect to the yoke thereby to prevent detachment of the yoke from the end member; and said button containing cavities into which the arms of the yoke snugly fit to fix the button upon the yoke.

References Cited in the file of this patent UNITED STATES PATENTS 2,106,581 Unwin Jan. 25, 1938 2,376,403 Thompson May 22, 1945 2,750,463 Roeser June 12, 1956 2,815,420 Meyer Dec. 3, 1957

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