US2402838A

US2402838A - Snap-action switch

Info

Publication number: US2402838A
Application number: US516385A
Authority: US
Inventors: Obszarny Thedore
Original assignee: Guardian Electric Manufacturing Co
Current assignee: Guardian Electric Manufacturing Co
Priority date: 1943-12-31
Filing date: 1943-12-31
Publication date: 1946-06-25
Anticipated expiration: 1963-06-25
Also published as: FR1067801A; BE482396A; GB649821A

Description

June 25, 1946. T, QBSZARNY 2,402,838

SNAP-ACTION SWITCH Filed D80. 31, 1943 Ilsa/alto;

war/Z656 Patented June 25, 1946 SNAP-ACTION SWITCH Thedore Obszarny, Chicago, Ill., assignor to Guardian Electric Manufacturing 00., Chicago, 11]., a corporation of Illinois Application December 31, 1943, Serial No. 516,385

4 Claims.

. 1 This invention relates to the electric switches of the snap-action type adapted for rapidly mak-' ing and breaking electric circuits. More specifically, my invention is directed to snap-action switches of the blade type adapted for controlling either single or multiple circuit, and wherein the switch includes a moveable member adapted to be actuated by relatively small or light force to efiect operation thereof.

The present invention is directed to certain novel improvements and refinements in snapaction switches of the type disclosed Lil). my United States Letters Patent No. 2,378,784, dated June 19, 1945, wherein the switch includes an elongated, resilient moveable contact member and a cooperating resilient, actuating member, and wherein the free end portion of one of the members is formed with a yoke portion, disposed in surrounding relation to the free end portion of the other member, and wherein the free ends of said members are inter-connected by a resilient toggle serving to normally urge the free ends of the two members apart.

One of the objects of the present invention is to provide an improved snap-action switch of the character indicated wherein the resilient toggle connection between the movable contact member and the actuating member is seated on knife edge fulcrums.

Another object is to provide a novel snapaction switch of the character indicated which is so constructed and arranged as to preclude possibility of the moveable contact member and actuati'ng member acquiring a balanced or dead center condition of adjustment, with the contact of the moveable contact member out of engagement with the cooperating fixed contact.

A further object is to provide an improved snap-action switch of the character indicated which is so constructed as to provide minimum frictional resistance due to rocking action of the resilient toggle, and which is positive and sensitive in operation.

Other objects and advantages of this invention will be apparent from the following description, taken in connection with the accompanying drawing in which: I

Figure 1 is a top plan view of the snap-action switch embodying the present invention.

Figure 2 is a side elevational view of the switch.

Figure 3 is a vertical longitudinal section through the switch taken, substantially as indicated at line 3-3 on Figure 1.

Figure 4; is a transverse sectional view through the switch, taken substantially as indicated at line |4 on Figure 2.

Figure 5 is a fragmentary view, partly in section and partly in elevation, through the resilient toggle connection, taken substantially as indicated at line H on Figure 2.

Figure 6 is a fragmentary plan view of the outer end of the actuating member.

Figure 7 is an enlarged sectional view, taken substantially as indicated at line '|1 on Fi ure 6.

Figure 8 is a fragmentary plan view of the outer end of the moveable contact member.-

Figure 9 is an enlarged sectional view, taken substantially as indicated at line 9-9 on Figure 8.

The switch construction as represented in the drawing, is of the so-called "stack type wherein two separate electric circuits are adapted to be controlled by actuation of the switch, and it is manifest that the switch may be constructed for controlling a single circuit. While I have shown in the drawing a switch construction wherein the actuating member must be moved from a normal inoperative position to and beyond an over center position for actuating the switch, and upon removal of the pressure on the actuating member the switch again returns to its normal, or initial position of adjustment, it will be apparent that, if desired, the switch may be so arranged so as to require an actuating force for moving the switch from one position to the other and for moving it from the latter position to the former position. It is also to be understood that the novel characteristics of this invention may be embodied in a snap-action switch of the block type wherein the cooperating blade members are rigidly mounted at one end on a block of insulating material, such as represented inFigures 6 and 9 of the drawing of my above mentioned co-pending application.

The switch as represented in the drawing, includes a pair of superimposed, elongated, relatively rigid, spaced-apart contact bars or fingers, l 0 and II, provided at their outer ends with contact buttons Illa and lla respectively, and their opposite ends being rigidly mounted in insulated relation to each other, between a plurality of insulating blocks or wafers, l4.

Mounted between the contact bars Ill and I I is a relatively resilient, elongated, moveable contact member l5, provided at its free end, on opposite sides thereof, with contact buttons l 50 and lib, adapted to cooperate respectively with the contact buttons Ilia and Ila of the contact bars insulating blocks I4, in spaced insulated relation to the contact bars Ill and II.

An elongated, stamped yoke member ii, of resilient metal, which for convenience may be termed the actuating member, is mounted at its.

of the moveable'contact member. The contactbars l and II and the moveable contact memher Ii are provided at their rear end portions with laterally extending ears or lugs, indicated at Inc, Ilc and lie respectively, to which maybe conveniently connected, as by soldering, con-- ductor wires of the electrical circuits to be controlled by the switch.

The insulating blocks I 4, together with the switch elements, aswell as the actuating member I8, are each provided with a pair of longitudinally spaced-apart aligned apertures, in which are snugly fitted tubular insulating sleeves I9, so as to positively insulate the rigid contact bars III and II and the moveable switch member Ii, from each other. The assembly of the various elements, in stack formation on the tubular insulating sleeves, is adapted to be secured to a convenient mounting by means of bolts or screws as indicated at 2|.

As may be seen in Figure 1 of the drawing, the opening lid of the yoke portion of the actuating member I8 is so dimensioned as to permit free movement of th outer end portion of the moveable contact member Ii and actuating member l8 relatively to each other.

The extreme outer end portion of the moveable contact member Ii is provided with a projection lid, partially formed by a pair of spaced-apart longitudinal incisions l is in the extreme end portion of said member, as clearly seen in Figure 8 of the drawing. The projection lid is formed in upwardly oiiset relation to the main body por-- tion of the member Ii, as clearly seen in Figure I89 are preferably located substantially centrally of the thickness of the respective projections lid and lid, as shown in Figures 9 and 7 of the draw- The knife edges lig and Ila of themoveable contact member I! and actuating member II, respectively. constitute abutment shoulders or seats, which serve as fulcrums or axes for the rocking movement of a resilient toggle connection, which as herein shown, includes a pair of flanged

tubular eyelets

22 and 23, disposed in telescopic relation to each other, with their flanged ends surrounding the respective projections lid and 18d of said members and seating respectively upon the two sets of knife edges lig and IE9, of said members. A coil spring 26 surrounds the pair of tubular eyelets and abuts at its opposite ends against the inner faces of the flanges thereof, tending to urge the eyelets apart, and likewise tending to urge the free end portions of the respective members I5 and I8 apart, as seen in Figures 2 and 3 of the drawing.

When force is initially applied to the outer end of the actuating member I i, for actuating the switch, said member is moved from the position seen in Figure 2 in the drawing, to the position seen in Figure 3 of the drawing. For causing such actuation-of the switch it is only necessary to move said member through and beyond the plane of alignment with the outer free end portion of the moveable contact member Ii. As the member I8 passes beyond said plane, the moveable contact member Ii is moved by virtue of the resilient toggle connection, with a snap-action 9 of the drawing. The portions on opposite sidesof the projection lid are bent upwardly as seen in Figures 8 and 9, in a manner to provide true knife edge fulcrums, as indicated at Iig, which actually is an edge defined by the juncture of one of lower face and the end face of the moveable contact member Ii.

The yoke portion of the actuating member, at the inner edge of the opening adjacent the end oi. moveable member Ii, is provided with a projection lid, partially formed by a pair of spacedapart longitudinal incisions He, said projection being upwardly offset with respect to the main body of the actuating member, as clearly seen in Figure '7. Similar incisions Iii, in alignment with the side edges of the yoke opening, define portions on opposite "sides of the projection lid which are bent upwardly as seen in Figure '7 to provide true knife edge rocking fulcrums as indicated at l8g, defined by the lower face and said inner edge of the yoke opening of said member to separate the contact buttons lie and I be and cause firm contact engagement of the contact buttons lib and Ila a seen in Figure 3 of the drawing. During such movement of the actuating member I8 the coilspring 25 becomes slightly compressed until the actuating member Ii approaches alignment with the flexible contact member I i, and as the actuating member passes beyond the plane of a free end portion of said member I i, the force of the compressed spring is expended to move the contact member Ii with snap-action to it opposite position of adjustment. When force is removed from the actuating member I8, the switch again assumes a position as seen in Figure 2 of the drawing. As above stated however, the actuating member I8 may be so constructed and arranged as to cause the switch parts to remain stable in either of its two positions of adjustment as represented in Figures 2 and 3 of the drawing, which would necessitate force being applied to opposite sides of the actuating member for moving the switch from one position to the other.

It will be apparent that the spring 25 is at all time confined d telescopic movement of the eyelets and precl, des lateral buckling of the spring during such movement. Thus the full balanced pressure of the spring is utilized for effecting the snap-action movement of the moveable contact member I5, and tends to maintain a uniform pressure between the contact buttons of the moveable contact member and the respective, fixed contact bars I0 and II. By virtue of the true knife edge fulcrums constituting seats for the resilient toggle, friction incident to rocking movement of the toggle is reduced to a minimum and the toggle i sensitive and responsive to extremely small amounts of movement of the actuating member I8, with respect to a moveable contact member Ii. By actual tests it has been found that when the actuating member II is moved at an extremely slow rate of speed, that as it approaches alignment with the plane of the moveable contact member that the snap-action of the switch will occur by further movement of. approximately one thousandth of an inch. Hence it is practically an impossibility to have the actuating member and moveable contact member acquire a state of balance or dead center relation, with the contact buttons of the moveable contact member out of engagement with either of the cooperating contacts of the fixed contact bar and II. This extreme sensitivity of actuation is of utmost importance when the switch is used for controlling the operation of certain apparatus. To more clearly represent the true knife edge fulcruming action of the resilient toggle connection, I have shown diagrammatically in Figures '7 and 9 of the drawing two sets of dot and dash lines, A and B, designating respectively the planes of abutment of the flanges of the

respective eyelet

23 and 22 at the two opposite positions of snap-action adjustment of the switch. The lines designated A, corre- 6 in the normal inoperative position of the switch. Although I have herein shown and described a certain preferred embodiment of my invention, manifestly it is capable of modification and rearrangement and adaptation to other forms of toggle connections without departing from the spirit and scope of this. invention. I do not. therefore, wish to be understood as limiting this invention to the precise embodiment herein disspond to the planes of the abutment face of the flanges of the eyelets when the switch is in the position of adjustment as seen in Figure 2 of the drawing, and the line B designate the planes of the abutment face of the flanges of the eyelets when the switch parts assume the position seen in Figure 3 of the drawing.

In the construction disclosed, and as commercially manufactured, the moveable contact member I5 is made of suitable resilient material of .010" and the resilient material for the actuating member I8 is made of resilient material of .020". It has been found that even with these relatively thin metals that it is possible without applicant's invention to have a switch rendered inoperative and defective by acquiring a balanced or dead center balanced condition wherein the contacts of the moveable contact member are out of engagement with both of the contacts of the fixed contact bars I!) and II, at which position all of the electrical circuits controlled by the switch are open. By virtue of the present construction this condition is for all practical purposes totally eliminated.

For certain uses of the snap-action switch embodying the present invention, I provide a plug of insulating material 21, at the extreme outer end portion of the actuating member l8, whichv plug is adapted to be engaged by any suitable element for applying force or pressure to the actuating member for causing the switch to move from the position seen in Figure 2 of the drawing to the position seen in Figure 3 of the drawing.

To limit the downward movement of the actuating member as seen in Figure 2 of the drawing, I provide a relatively rigid, elongated strip of insulating material 30, mounted against the upper face of the contact bar H with one end thereof fixedly mounted in the stack assembly with the insulating blocks l4, so as to become a part of the total assembly.

The outer or free end of the insulating strip is formed with an arcuate notch 3|, so as to provide clearance for the contact button I la, and to avoid possible interference with the making of proper contact between the contact button I51) and the contact Ila. Said insulating strip 30 has the additional function of retaining the switch parts in a condition of adjustment so as to obtain maximum advantage of the pressure of the spring 25 of the toggle connection for insuring adequate pressure between the contact buttons We and Illa closed, except as I may be so limited by the appended claims.

I claim as my invention:

l. In a snap-action switch comprising a fixed contact, an elongated, resilient contact member movable into and out of cooperative engagement with the fixed contact, an elongated, resilient actuating member, said members extending in the same direction in superimposed relation and being mounted at one of their corresponding ends, the other ends of said members being free to move relatively to each other, the free end portion of one of said members being formed as a yoke disposed in surrounding relation to the free end portion of the other member, the free end portions of each of said members being provided with a projection, said projections extending toward each other, and resilient toggle means engagin said projections for normally urging the free ends of said members apart whereby movement of the free end portion of the actuating member through and beyond the plane of the free end of the moveable contact member causes said toggle means to be rocked to effect movement of said moveable contact member with a snap-action into or out of cooperative engagevment with the fixed contact; the improvement characterized by the projection on one of said members being laterally offset from the planes of thickness of said one member, and the provision of abutment shoulders adjacent the projection on each member to constitute rocking seats for said toggle means, said shoulder of said one member being formed by a portion bent in the direction of offset of said projection, with the juncture of two contiguous surfaces of said portion constituting a single knife-edge fulcrum.

2. In a snap-action switch comprising a fixed contact, an elongated, resilient contact member moveable into and out of cooperative engagement with the fixed contact, an elongated, resilient actuating member, said members extending in the same direction in superimposed relation and being mounted at one of their corresponding ends, the other ends of said members being free to move relatively to each other, the free end portion of one of said members being formed as a yoke disposed in surrounding relation to the free end portion of theoth'er member, the free end portions of each of said members being provided with a projection, said projections extending toward each other, and resilient toggle means engaging said projections for normally urging the free ends of said members apart, whereby movement of the free end portion of the actuating member through and beyond the plane of the free end of the moveable contact member causes said toggle means to be rocked to effect movement of said moveable contact member with a snapaction into or out of cooperative engagement with the fixed contact; the improvement characterized by the projection on one of said members bein laterally offset from the planes of thickness of said one member, and the provision of abutment shoulders adjacent the projection on each member to constitute rocking seats for said toggle 7 means, said shoulder oi said one member being formed by a portion bent in the direction oi oi!- set-oi' said projection, with the juncture of two contiguous surfaces of said portion constituting a single knii'e-edge fulcrum, disposed intermediate the planes defining the thickness of said P oflset proiection.

3. In a snap-action switch comprising a fixed contact, an elongated, resilient contact member moveable into and out of cooperative engagement with the viixed contact, an elongated, resilient actuating member,- said members extending in a free end portion oi the other member.- the freeend portions of each of said members being provided with a projection, said projections extending toward each other, and resilient toggle means engaging said projections for normally urging the free ends of said members'apart, whereby movement of the free end portion of the actuatin end of the moveable contact member causes said toggle means to be rocked to eflect movement of said moveable, contact member with a snapaction into or out of cooperative engagement with the fixed contact; the improvement characterized by the projections being laterally offset from the planes of thickness of said members, and the provision of abutment shoulders at opposite sides of each projection to constitute rocking seats for the toggle means, said shoulders of the respective members being formed by portions being bent in the direction of oifset of the projection on the respective members with the juncture of two conmember through and beyond the plane of the tree a v 4 8- tiguous suriaces of said heat portions constituting single knife-edge iulcrums.

4. In a snap-action switch comprising a fixed contact, an elongated, resilient contact member moveable into and out of cooperative engagement with the fixed contact, an elongated, resilient actuating member, said member extending in the same direction in superimposed relation and being mounted at one of their corresponding ends, the other ends of said members being free to move relatively to each other, the free end portion of one of said members being formed as a yoke disposed'in surrounding relation to the free 'end portion of the other member, the free end portions 01 each of said members being provided with a projection, said projections extending toward each other,.and resilient toggle means engaging said projections for normally urging the free ends of said members apart, whereby'movement or the free end portion of the actuating member through and beyond the plane 01' the free end of the moveable contact member causes said toggle means to be rocked to efiect movement of said moveable contact member with a snapaction into or outof cooperative engagement with the fixed contact; the improvement characterized by the projections being laterally offset from the planes of thickness of said members, and the provision of abutment shoulders at opposite sides of each projection to constitute rocking seats for the toggle. means, said shoulders of the respective members being formed by portions being bent in the direction of oifset of the projection on the respective members with the juncture of two con tiguous surfaces of said bent portions constituting single knife-edge fulcrums, disposed intermediate the planes defining the thickness of the offset projections of the corresponding members.

THEDORE OBSZARNY.