US2498020A - Electric snap switch - Google Patents

Description

Feb. 21, 1950 F. J. TRAINOR 2,498,020

ELECTRIC SNAP SWITCH Filed Sept. 29, 1947 2 She'ts-Sheet 1 INVENTOR. FOSTER J TRAINOR BY 1% WWW;

ATTORNEY Feb. 21, 1950 Filed Sept. 29, 1947 F. J. TRAINOR ELECTRIC SNAP SWITCH 2 Sheets-Sheet 2 INVENTOR. FOSTER J, TRAINOFZ 11h MU ATTO RNEY Patented Feb. 21., 1950 ELECTRIC SNAP SWITCH Foster J. Trainor,-Holly ,Hill, Fla., assignor to Disto Corporation, Holly Hill, Fla.

Application September 29, 1947, Serial No. 776,771

10 Claims. 1

My invention relates to an electric snap switch.

The object of my invention is to provide a novel snap element for use in snap type electric switches, whereby the switch assembly will consist of a minimum number of parts which can be assembled with a minimum of labor, and when so assembled, provides a compact, reliable and economical mechanism.

The following is a description of my invention, reference being made to the accompanying drawing in which:

Figure 1 is a side view of a single pole double throw snap switchembodying my invention.

Figure 2 is a cross sectional view through plane 2-2 of Figure 1.

Figure 3 is a cross sectional. front elevation of a modified version ofmy switch.

Figure 4 is a section through plane 4.@ of Figure 3.

Figure 5 is a fragmental showing on plane 55 of Figure 3.

Figure 6 is a perspective top view of the snap element in the switchcasing.

Figure 7 is a bottom view of the casing lid.

Figure 8 is a side View of the snap element.

Figure 9 is an end-wise view of the snap element.

In the drawing, the numeral I refers to the snap element per se. This element is made of a resilient material such as Phosphor-bronze and consists generally of a rectangular sheet of suitable size having a substantially semhcircular portion removed from one edge thereof midway between the ends. The material along the semi-circle is stretched or expanded as by peening in order that the. element shall take on a convex shape. It is apparent that if the sheet of resilient material is supported by its ends and the edge opposed to the cut-out portion, that pressure applied to the surface of the sheet on the convex side will cause the sheet tospring to the opposite convex condition. In other words, a sheet of resilient material prepared in accordance with my invention has two conditions of stable equilibrium, and can be made to snap from one of the stable conditions to the other merely by. impressing a force on the convex side,

I apply the snap element to a switch wherein I provide a support for the two ends and the edge opposed to the cut-out, and I further provide switch contact elements in any. convenient. man- 2 ner, and I haveshown the same as separated from the snap element although it is obvious that the material of the snap element can-constitute part of the electrical contacting means if desired.

In Figure l, I show a frame for supporting the snap element consisting of verticalmembers 2 and bottom and top members 3 and 4 respectively. The vertical members and the top. memher have aligned grooves, the bottom of which is indicated by the dotted line 5, I-providean aperture in the top member at about the. median line of the snapelernent, for the purpose :01. accommodating a handle element '6, This;v handle element is provided with a .longitudinalrslot in its lowerportion for the purpose of receiving apart of the snap element as best seen in Fi ure I provide a conducting element in sheet form which is also received in the slot '5 of the-lowerextending portion of the handle element.

The handle elementis securedto the snap element. i and the conducting element.. 8 which is the throw. contact of the swi ch by any suitable' means such as. small olts. dhesive ore I have shown, rivets 9. The rivet passing through the throw contact "is in conducting relation withthe same. The throw element is spaced fromthesnan element in the oove f the han le element 55 if any of t frame mb rs are fabricat-ed ofcohducting material. ,If. he frame isof insulating material itis imm er al whe r he contacting element is insulated from the snap element, andin fact the contacting element 8 can be integral with the snap element.

I provide a connecting means to thethrow contact by securing the flexible jump r B tathe rivet which I have previously described as contactics thev sarca. nd I provide. bindineg ost H which is. insulatinglyv supported on-the switch frame and'to which the jumper is-attached.

I also provide stationarycontacts l2 and :l3 on the bottomframe mem r nd in theplah of the arc of rotation of the throw contact 8. Binding posts 15 and M are provided in conducting relation with the stationary contacts 12 and i3 respectively.

The aperture in the top member 4 through which the handle element projects is of a size slightly larger vthan the cross section of the handle and is provided with arcuate or convex surfaces inthe two sides normal to the axis of rotation to thereby provide fulcrumbearing surfaces for the handle.

Ishow a prefe r d em d ent in i res .3 to 7 inclusive. A casing is provided having any desired external configuration, but which for purposes of illustration is shown as rectangular in Figure 6. This casing is provided with a pair of opposed grooves in the lateral sides thereof. These grooves may be molded into the casing wall or may be provided by molded bosses as shown.

The lid 2| appears from the underside as shown in Figure 7 and is provided with a transverse groove between a pair of integral bosses as shown. The groove in the lid is so located that it is continuous with the grooves in the casing when the lid and casing are assembled, as shown in Figure 5.

At a position substantially midway between the ends of the snap element receiving groove in the lid I provide a rectangular handle receiving aperture. The groove bosses are removed on planes normal to the plane of the lid at the lateral edges of the aperture. The purpose of this being to restrain a rectangular handle element to a rocking motion in a plane normal to the direction of the lid snap element receiving groove.

The handle 24 is an elongated element having a rectangular cross section along a portion thereof and the remainder having special configurations for purposes now to be described. At the end of the rectangular cross sectional portion and about midway of its length I provide an enlarged section having surfaces on both sides of the rectangular portion normal to the plane of rotation, of the general shape of cylinders of rotation, to provide bearing surfaces therefor. These bearing surfaces are indicated by the numeral 25 in Figure 4.

The underside of the aperture in the lid is likewise provided with cylindrical surfaces 26 to provide the stationary bearing for the handle element portion 25, whereby the handle is enabled to rotate to and fro through a limited arc.

In the andlle element and starting substantially at the center of rotation of the arcuate bearing surfaces thereon, I provide a transverse slot therein extending through the remaining length thereof, and of a width to accommodate the snap element.

While it is the primary purpose of my invention to provide a new type of snap actuating mechanism for a switch, and I contemplate that any of the contact arrangements commonly applied to snap action or toggle switches can be used in my switch, I have shown one very simple form of contacting arrangement in Figure 4. In this embodiment I provide a lateral projection on the side of the lower portion of the handle element. This projection indicated by the numeral 21 is of such a length that positive pressure under the influence of the snap element is exerted against a spring contacting element 28 thereby causing the same to contact the switch element 29 and to connect the same to binding post 38. The spring contacting element is of such an initial configuration that it springs away from conple. I first slip the snap element in the lateral grooves of the casing. In this regard I wish to point out that provision is made to provide clearance between the bottom of the snap element and the bottom of the casing by either terminating the casing grooves slightly short of the hottom of the casing or by removing small wedge shaped portions between the edges and the semicircle on the bottom, as shown in Figure 3.

The remaining steps in the assembling of the switch consists in assembling the handle element in th lid and placing the lid in position on the casing and securing it thereto.

What I claim as new and desire to secure by Letters Patent is:

1. In an electric snap action switch, a snap action element comprising a resilient metallic sheet bounded on first and second sides by parallel edges, on a third side by an edge substantially normal to said parallel edges and connecting an end of each of the same, on a fourth side by an edge including a re-entrant curved portion, said curved portion having a longer length than the projection of the curved portion on a plane passing through the parallel edges, whereby said sheet has two convex conditions of stability with an intervening condition of instability.

2. In an electric snap action switch, a snap action element comprising a resilient sheet hav-- ing a generally rectangular shape, and being bounded on three sides by straight edges lying in a common plane, and being bounded on the fourth side at least in part by a re-entrant curved edge, said re-entrant curved edge being longer in length than the projection of the curved edge on said common plane, whereby the portion of the sheet adjacent the curved edge is caused to assume a convex configuration, and whereby said. sheet has two conditions of stability with an intervening condition of instability.

3. The combination of a snap action element and an operator element including a sheet of resilient metal material having a boundary portion on at least half of its perimeter lying in a plane, and having in the remaining boundary a reentrant curved portion, said re-entrant curved portion being longer in length than a projection of the same on the said plane whereby the snap element is caused to assume a convex shape; said operator element having a bifurcated portion straddling the resilient sheet along the median line of the re-entrant curved portion, means for supporting the boundary portion lying in a plane and means for pivotally supporting the operator element for limited pivotal motion transverse to a tangent to the curved portion where straddled by the operator element, whereby said snap element can be transformed from either condition of convexity to the other condition of convexity by pressure on said operator element and whereby said snap action is obtained by a wave motion passing along the sheet material along the curved boundary in two directions away from the operator element.

4. In a snap action device, a sheet of resilient metal having a generally rectangular outline being bounded on three adjacent sides by edges lying in a plane and being bounded on the fourth side by an edge including a re-entrant semicircle, said semi-circle having a length longer than the projection of the same on the said plane, whereby said resilient sheet is caused to assume the shape generally of an axially bisected frustocone; means for moving the middle portion of said semi-circle in a direction opposed to the direction of the frusto-cone whereby a condition is reached in which said middle portion is urged past the said plane and consummating by a wave motion the reversal in direction of the bisected frusto-cone.

5. In a snap action switch, a snap action element, a frame, and a handle; said snap action element comprising a sheet of resilient material having a re-entrant curved boundary on one edge thereof intermediate the ends thereof and being elongated in the portion adjacent said curved boundary; said frame having a pair of opposed parallel grooves and a third groove normal to and joining said pair of grooves to provide a support for two end edges and an edge opposed to the edge containing the curved boundary of the snap action element; said handle element being bifurcated in its lower portion whereby it is adapted to straddle the snap action element, and having a pivot portion intermediate its length, whereby a force applied to said handle in a direction to impress a force on the snap action element causes the said snap action element to snap by a wave motion into an alternate condition.

6. In a snap action switch, a snap action element, a frame, and a handle element; said snap action element being a sheet of resilient metal and having a rectangular shape except for a semi-circular portion removed from one of said edges mid-way of the ends thereof, the material of the sheet adjacent the semi-circular boundary thereof being expanded whereby said sheet has two convex conditions of stability with an intervening condition of instability; said frame having grooves in two opposed sides thereof lying in a single plane and a groove in a third side thereof normal to the first grooves and joining the same whereby a support is provided for the ends and the edge of the snap action element opposed the the edge having the removed portion; said frame having an aperture in said third side symmetrical with the groove therein, adapted to receive a portion of said handle element; said handle element being elongated and having a handle portion, a pivot portion and a bifurcated portion, said pivot portion being adapted to engage the walls of the aperture in said frame third side, and said bifurcated portion being adapted to straddle said snap action element; whereby a force applied to said handle portion in a direction to transmit a force to the convex side of the snap action element causes the same to snap into its alternate convex condition.

7. The device of claim 6 wherein stationary contacts are supported on the frame, and a movable contact is attached to the bifurcated end of said handle element.

8. In a snap action a switch, a casing, a snap action element, and a handle element; said tea ing having a central chamber circumscribed by lateral and end walls and a bottom wall and a detachable lid, a pair of opposed vertical grooves in said lateral walls, and a groove in said lid joining the vertical grooves; said snap action element comprising a sheet of resilient metallic material having a generally rectangular boundary and having a length substantially equal to taining the semi-circular groove adjacent the bottom of said casing; said lid having a cylindrical portion removed midway of the groove therein and extending through said lid to provide an arcuate bearing surface; said handle element having a handle portion, an enlarged intermediate portion having a pair of cylindrical surfaces and a lower portion having a bifurcation and a lateral extension, said handle being adapted to straddle said snap element and to pivot in said lid arcuate bearing surface.

9. The device of claim 8 wherein wedge shaped portions are removed from the lower edge of said snap element.

10. The device of claim 9 wherein switch elements are supported on an end wall of said casing and adapted to close when engaged by said handle element lateral extension.

FOSTER J. TRAINOR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 186,169 Rowbotham Jan. 9, 1877 1,200,847 Kaisling Oct. 10, 1916 1,593,511 Spencer July 20, 1926 1,895,592 Spencer Jan. 31, 1933 1,929,545 Arnold Oct. 10, 1933 2,340,615 Rath Feb. 1, 1944 2,368,193 Boynton Jan. 30, 1945

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