US2378784A

US2378784A - Snap-action switch

Info

Publication number: US2378784A
Application number: US479180A
Authority: US
Inventors: Obszarny Thedore
Original assignee: Guardian Electric Manufacturing Co
Current assignee: Guardian Electric Manufacturing Co
Priority date: 1943-03-15
Filing date: 1943-03-15
Publication date: 1945-06-19
Anticipated expiration: 1962-06-19
Also published as: GB646476A; BE482394A

Description

June 19, 1945. r OBSZARNY 2,378,784

SNAP-ACTION SWITCH Filed March l5, 1943 2 Sheets-Sheet l Jiffy/a 'azz lllllllllllllirllAf-m June 19, 1945. T. oBszARNY 2,378,784

SNAP-ACTION SWITCH Filed March 15, 1943 2 Sheets-Sheet 2 Patented June 19, 1945 UNITED 'STATES PATENT lOFFICE SNAP-ACTION swrrca Thedore Obszarny, Chicago, Ill., assigner to Guardian Electric Manufacturing Co., Chicago, lll., a corporation of Illinois application March 15, 194s, serial No. 479,180

z claims. (ci. zoo-.61)

This invention relates to electrical switches a cooperating resilient actuating member, and of the snap-action type, -adapted for rapidly wherein one of the members is formed with a making and breaking electrical circuits. yoke portion disposed in surrounding relation to More particularly my invention is directed to the free end portion of the other member, and snap-action switches of the blade type adapted 5 wherein the free ends of said members are interfor controlling either single or multiple circuits, connected by a coil spring toggle serving to norand wherein such switches are usually of a relamally urge the free ends of the members apart. tively small compact construction, requiring a The present invention is directed to improvereliively Small r light force to effect operation ments in snap switches of the type referred to thereof. Due to the construction and character 1o in the foregoing paragraph, and has for one of of operation of switches of this type as heretoits objects the provision of stop means for limitfore manufactured, they have necessarily been ing the movement of the actuating member relamade as precision devices, requiring relatively tive to `the contact member, in one direction, to small tolerances. preclude separation of the switch contacts.

Certain switches of this general type. now availl Another object is to provide improved stop able, are manufactured to such precision that it means locatedyin a position so as to be directly has been found desirable to perform certain operengaged by the Vactuating member for limiting ations 0n Darts thereof after complete assembly movement relative -to lthe movable contact memof the switch. Such operations obviously inber in one direction.

crease cost of manufacture of the switch. More- A further object is .to provide a novel form and over the switches of this general type now availarrangement cf stop means, which is in .the na- Bille Practically 91,11, include e movable member ture of a cantilever member, positioned to be or element formed of a strip of spring metal directly engaged by the actuating member for which is mifmuy deformeg 'to provide what is limiting i-ts movement in one direction and by known as a sensitive area to which area presvirtue of its construction, is adapted to permit Sure is applied @C produce mixing of the Contact a slight excessive amount of movement of the frying portion of the member with a snap actuating member, as a safety factor, in the event action. Another construction oi' this general type utilizes a. strip of spring metal which is initially lgttlerggttmg member moved through too bowed and held .in such position so that it func' 30 Other objects and advantages of my invention tions as a tension member. Still another type i will be apparent from the following description utilizes a strip of spring metal disposed m bowed taken in connection with the accompanying formation between the free ends of two relatively drawings m which: movable actuating members and contact mem- Figure 1 is a top plan View of a switch em] dy bers of the switch. 35

ing the present invention. All of such switch structures above referred to Figure 2 is a side elevational view of the switch. are of somewhat limited life` because of the tend Figure 3 is a vertical longitudinal section ency of the strip of deformed or tensioned spring metal to cr tamz a en;` i through the switch, taken substantially as indiys e t c a n areas due to Ire cated on lines 3--3 of Figure 1, showing the switch quent flexing 'actuation thereof. 40 c Another objectionable characteristic lof a switch m another position of adjustment' of the last-mentioned type, is that in the event Figure 4 is a transverse sectional View 'through of excessive movement of the actuating member the Switch taken substantially as indicate@ on in one direction, the pressure between the switch unes 5 4 0f Figure 2- contacts is reduced, and in some instances may Figure 5 .is a fragmentary View' partly in sec' even result in separation of the contacts. This non and Partly in, elevation through 'the Spring condition is highiy objectionable particuIariy in toggle connection. and taken substantially as ciectricoi circuits where it is important that after indicated cn lines 5-5 cf Figure 2.

a contact is made, such contact be maintained Figure 6fis a top Plan View 0f a modified fOrm for a certain period of time. 60 of snap switch, embodying the present invention.

More specifically this invention is directed to Figure 7 is a side elevational view of the modiimprovemen-ts in a switch of the type disclosed iicd i0rm 0f my SWiiChin my copending application Serial No. 465,332, Figure 8 is a .transverse sectional view through filed November l2, 1942, wherein I employ an the switch taken substantially as indicated on elongated, resilient, movable contact member and lines 8--8v of Figure 7.

Figure 9 is an end elevational view of the contact making and breaking end of the switch.

Referring now to the switch construction disclosed in Figures l to 5 of the drawings, it will be noted that said switch is of the so-called stack type and includes a pair of superimposed, elongated, relatively rigid spaced apart contact bars or fingers IU and II provided at their outer ends with contact buttons I la and IIa respectively. The contact bars are rigidly mounted at their rear ends in insulated relation to each other between a plurality of insulated blocks or waters I I.

Mounted between the contact bars III and II is a relatively resilient, elongated, movable contact switch member I5, provided at its free end, on opposite sides thereof, with contact buttons I5a and I 5b adapted to cooperate respectively with the contact buttons Ia and II a of the contact bars I and II.` The movable contact mem.

ber I is mounted at its rear end in the stack of insulating blocks I l, in spaced insulated relation to the contact members I0 and II as seen in the drawings.

An elongated stamped yoke member I8, of resilient metal, which may be termed the actuating member, is flxedly mounted at its rear end in contact with the rear end portion of the movable contact member I5, in insulated relation to the contact bars I0 and II, and has its outer or free end portion disposed in surrounding relation to the outer free end portion of the movable contact member. The relatively rigid contact .bars I0 and II and movable contact member I5 are provided at their rear ends with laterally extending ears or lugs indicated at IIlc, IIc and I5c respectively, to which may be conveniently connected, as by solderingl conductor wires of the electrical circuit to be controlled by the switch.

As is conventional in switches of this general type, the insulating blocks Il and switch elements, as well as the yoke member I8, are each provided with a pair of aligned apertures in which are snugly fitted tubular insulating sleeves I9. so as to positively insulate the relatively rigid contact bars I0 and I I, and the movable switch member I5 from each other. To further rigidify the entire assembly, the stack of insulating blocks are capped, both at the top and bottom, by metal plates 20, and the total stack assembly is adapted to be secured to a convenient mounting by means of screws or bolts as indicated at 2 I.

It will be noted that the opening Ia of the yoke of the actuating member I5 is so dimensioned as to permit free relative movement of the free end portion of the movable contact member and actuating member relatively to each other.

The extreme outer free end portion of the movable contact member I5 is provided with a projection I5d, which is in the nature of a tapered tang, and the yoke member, at the adjacent inner edge of the opening, is provided with a projection `ltd extending in the direction of the projection I5d, and which likewise is in the form of a tapered tang. The marginal edge portions of the respective members I5 and I8 immediately adjacent the respective projections serve as abutment shoulders,

The two members I5 and I8 are interconnected at their free outer ends by a toggle spring arrangement which includes a pair of flanged

tubular eyelets

22 and 23 disposed in telescoping relation to each other, with their flanged ends surrounding the projections I5d and Ild of said members, and seated against said abutment :,svavas shoulders. A coil spring 25 surrounds the telescoping eyelets and abuts against the inner face of the ilanges of the respective eyelets, tending to urge the eyelets apart, and likewise tending to 5 urge the free end portions of the respective members Il and I8 apart. as seen in Figures 2 and 3 of the drawings.

It will now be apparent that when force is initially applied to the outer end of the yoke member I5 for causing it to move from the position seen in Figure 2 of the drawings to the position shown in Figure 3 of the drawings, only suiilcient movement is necessary to shift the yoke member I8 through and beyond the plane of the outer free end portion of the movable contact member I5, and as it passes beyond said plane, the movable contact member I5 moves, by virtue of the toggle spring connection, with a snap-action to separate the contact buttons I5a and Ia and cause iirm contact engagement of the contact buttons I 5b and IIa. It will be observed that during such movement of the actuating member I8, the coil spring 25 is slightly compressed, until the actuating member IB approaches alignment with the ilexible movable contact member I5, and as the free end of the actuating member passes over or beyond the plane of the free end portion c! said contact member, the force of the compressed spring is expended to move the contact member I5 with a snap-action, to its opposite position o! adjustment.

The extreme outer end portion of the actuating end portion I8 is provided with a plug 21 of insulating material, which is adapted to be engaged by any suitable element foi applying the force or pressure to the actuating member for causing it to move from the position seen in Figure 2 of the drawings to the position seen in Figure 3 of the drawings.

It is to be understood that in the construction disclosed, the actuating member I8, is so constructed that when pressure on the plug 21 is released, the switch parts automatically resume a position as seen in Figure 2 of the drawings. It is to be understood however that the actuating member I8 may be so constructed that the switch parts may remain relatively stable in either of its two positions of adjustment as indicated in Figures 2 and 3 of the drawings, while still obtaining the same substantial advantages of the snap-action employed.

It will be apparent that by reason of utilizing a pair of telescoping eyelets the coil spring 25 is at al1 times guided during its movement from one position of adjustment to the other, as illustrated in the drawings, and precludes any lateral buckling of the spring during such movement. 'I'hus the full balanced pressure of the coil spring is utilized for effecting the snap-action movement of the movable contact member I5. and also tends to maintain a uniform pressure between the contact buttons of the movable contact member I5 and the respective contact bars III and I I.

Because of the possibility of movement of the actuating member, in either direction, beyond what may be considered a proper or normal range, I provide suitable stop means in the form of relatively rigid elongated strips of insulating material as indicated at l0, mounted against the undersurface of the respective contact bars I0 and I I and having their ends mounted in the stack assembly between the insulating blocks Il so as to become a fixed part of the total assembly. As may be seen in the drawings, the insulating strips 30 are approximately of the same width as the overall width of the actuating member Il and are thus engageable by 'said member for limiting the movement thereof in either direction. as clearly seen in the drawings. The outer ends of the insulating strips 38 are formed with arcuate notches l8l so as to provide clearance around the contact buttons Ilia and ila respectively, to avoid possible interference with the making of proper contact with the contact buttons lia and IIb of the movable contactmember.

It will be observed that if the actuating member I8 is moved through too great a range, there is a normal tendency for the

eyelets

22 and 23 to become disengaged and render the switch inoperative. Further, such excessive movement decreases the pressure of the coil spring 25 and thus decreases the eil'ective pressure between the contact buttons. It is highly desired that the pressure between the contact buttons be oi suilicient quantity, in order to insure making of good electrical contact. By virtue of the provision of the stop members 80, the actuating member is arrested at a proper position, at opposite ends of a desired operating range of movement, at which it is possible to obtain the use oi' the full force of the coil spring 28 for maintaining the contact buttons in ilrm engagement with each other. 'I'he stops also serve the purpose of eliminating the tendency to deform the actuating member I8, which may result by movement thereof through too great a range, and which would impair proper snap-action operation.

In the modified constructions illustrated in Figures 6 to 9 inclusive, there is employed an elongated base member of suitable insulating material, which serves as the mounting for the snapaction switch. Rigidly mounted at one end of the base 88 is a relatively flexible elongated actuating member 88 and a relatively iiexible elongated movable contact member 31, the latter being formed as a yoke and dimensioned with respect to the actuating member 36 so as to permit rela-'- tive movement of the free end portions of the movable member relatively to each other. Said members are rigidly secured at one end, on said base by means ofA rivets 39. Mounted between the mounting ends of the respective members is a terminal plate 4| which includes an extension projecting around theadjacent end of the base and terminating at the underside thereof in an ear 4in. l

'I'he outer or free end of the movable contact member l1, which is of yoke formation, is provided at its opposite faces with contact buttons 31a and I'lb, adapted to engage respectively with contact buttons 44a and 45a of a pair of contact strips 44 and 45, rigidly attached to the opposite end of the base 40, at the underside thereof, as clearly seen in the drawings. The lower ends of said strips terminate in ears 44h and 45h. Said terminal ears 4ia, 44h and 45h are adapted to be connected, such as by soldering, to conductor wires for embodying the switch in an electrical circuit.

'Ihe free ends of the actuating member 38 and movable contact member 31 are provided with cooperating tangs or projections 36e and 81o and are interconnected by a spring toggle of the same general construction and arrangement as described in connection with the structure shown in Figures 1 (to 5 inclusive of the drawings, and the action of the spring toggle is identical and it is therefore deemed unnecessary to again repeat the construction and operation thereof, and the corresponding parts are accorded similar reference numerals, supplemented by the letter a.

In the' position of the switch parts as seen in Figure 7 of the drawings, the resilient actuating member 38 is seated upon the head 48 of an operating plunger pin 48, slidably guided in a suitable recessed aperture formed in the base 35. It will be apparent that when the outer or exposed end oi' the plunger 49 is depressed, the'head 48 impinging upon the ilexibie actuating member 36, moves the free end portion thereof through the opening of the yoke type movable contact member 81, and as it passes through and beyond the plane of the latter, the spring toggle arrangement operates with a snap-action to move the contact button 31a out of engagement with contact button 44a and causes engagement of the button 31h with the contact button 45a'. When pressure on the pin 49 is removed, the switch parts move with a snap-action to the initial position as seen in Figure 7. l

In the position of the switch parts seen in Figure 7 of the drawings, the head 48 of the plunger pin serves as a stop i'or limiting the position of the actuating member I8 in one direction. To limit the movement of said member in the other direction, -I provide a relatively rigid cantilever stop BI, mounted at one end on top of the movable contact member 3l, by means of the rivets 38. Thus the stop arrangement provided herein serves to limit the range of movement of the actuating member 38, so as to utilize and obtain the maximum advantage of the spring pressure of the toggle connection forf insuring proper pressure between the cooperating contact buttons.

I `Although I have herein shown and described certain preferred embodiments of my invention, manifestly it is capable of further modication and rearrangement of parts without departing from the spirit and scope thereof. I do not. therefore, wish to be understood as limiting this invention to the precise forms herein disclosed, except as it may be so limited in the appended claims. y

I claim as my invention:

1. A unitary, stack type, snap-action switch assembly comprising a pair of elongated, relatively rigid contact bars disposed in aligned, spaced apart relation, an elongated, resilient contact member movable into and out of engagement with said contact bars, an elongated, resilient actuating member, said members extending in alignment with said bars and rigidly connected at one end and the free end portion of one member being formed as a yoke and disposed in surrounding relation to the free end portion oi the other member, said contact bars being rigidly connected at one end in insulated relation to said rigidly connected ends of said members, the free end portions of said members being provided with projections extending toward each other, a spring toggle connection including a coil spring mounted on said projections and urging the free ends of said members apart, whereby movement of the outer free end portion oi the actuating member through and beyond the plane of the free end of the movable contact member effects movement of the later with a snap-action into and out oi.' engagement with said contact bars, and stop means positioned to be engaged by said actuating member for limitingits movement in one direction, said stop means comprising a relatively rigid strip of insulating material seated against the inner surface of one of said contact bars and rigidly connected at one end to the assembly of said bars and members.

2. A unitary, stack type, snap-action switch assembly comprising a pair of elongated, relatively rigid contact bars disposed in aligned, spaced apart relation, an elongated. resilient contact member movable into and out of engagement with said contact bars, an elongated. resilient actuating member, said members extending in alignment with said bars and rigidly connected at one end and the free end portion o! one member being formed as a yoke and disposed in surrounding relation to the free end portion of the other member, said contact bars being rigidly connected at one end in insulated relation to said rigidly connected ends o! said members, the free end portions of said members being provided with projections extending toward each other, a spring toggle connection including a coil spring mounted on said proiections and m1- ing the tree ends o! said members apart, whereby movement o! the outer free end portion of the actautins member through and beyond tbe piane oi the free end oi the movable contact member eilects movement o! the latter with a snap-action into and out of engagement with said contact bars. and stop means positioned to be engaged by said actuating member for limiting its movement in both directions, said stop means eamprising a pair of relatively rigid strips of insulating material seated respectively against the inner surfaces of said contact bars and rigidly connected at one end to the assembly of said bars and members.

'I'HEDORE QBBZARNY.