US2314995A - Electric switch - Google Patents

Description

March 3o, 1943.

Gf A. LENNHOLM ELECTRIC SWITCH Filed OCfc. 23, 1940 A TTORNE Y 1N VEA/TOR i g1/@afar E arUI/alz.

Patented Mar. 30,

ELECTRIC swrron` A Gustav A. Lennholm, nes Moines, iowa, assirnnr to Square D Compan poration of Michigan y, Detroit, Mich., a cor- .I imputation october z3, 1940, serial No. :02,339

' (o1. zoo-67) I 10, Claims.

'I'hls invention relates to electric switches and more particularly t an improved form of electric switch operating with a snap action.

One object of the present invention is to provide I an improved form of electric switch having an economy and simplicity of construction.

Another object of the present invention is to provide an improved form of electric switch having provision for breaking a contact weld and restoring the switch to. normal operation,

Another object of the present invention is to provide an improved form of electric switch in which the contacts are .so moved as to provide a substantial wiping action before moving to disengaged position.

Another object of the present invention is t0 provide an improved snap acting electric switch in which a substantial contact pressure is maintained until the instant/the contacts are quickly snapped to disengaged position.

Other objects and features of this invention will be readily apparent to those skilled in the art from the following specification and appended .drawing illustrating certain preferred embodi- Figure 4 is a sectional view on the line IV-IV of Figure 2.

Figure 5 is a sectional view on the line V V of Figure 1.

Figure 6 is a sectional view on the line VI--VI of Figure 2.

The switch of the present invention is adapted for actuation both manually, and automatically in response to an external force. The embodiment as illustrated can be used in connection with a float' for sump operations. Reversing of the switch top for bottom enables its use for tank operations.

closure I at one end thereof and on these ledges are secured conducting members 1 and H by means of studs 8 and I2, the member II being further secured to the back Wall lI3 of the en' closure as by a stud I4. Studs I5 and `I6 are threaded into the conducting members 1 and II members l and II by an upstanding wall portion- 2l.v A generally U-shaped lever or supporting member 22 is pivotally mounted upon the supporting member I9, the legs of the lever 22 pivoting within seats provided by the legs 23 and 24 of the supporting member I 9. switching member 25 formed of an insulating plate 26 and a metallic member 2l has an opening 2B therein through which projects a narrowed ex,-

tension 29 of the lever 22 with the shoulder portions 3I on the lever 22 affording a support for insulating plat. 26. loosely supported on the plate 26 at .one end thereof and serves to bridge the stationary contacts I'I and I8 to complete the circuit therethrough. A depending tongue 33 bent' from the metallic member 21 extends through opening 28.

and provides a point of attachment for one end of an operating spring 35. The tongue 3,3 is bent upwardly atits end 36 where the operating spring is attached and extends through the legs 31'and 38 of the lever member I9 when the contacts are in engaged position. This thus places the point -of attachment Aof the end of the spring 35 above the plane of the upper face of lever member 22 as viewed in Figure l for a purpose to be hereinafter described; 'l ie opposite end of the spring 35 is secured to a. generally U-shaped operator 4 I. The

'. operator is pivotally mounted upon the supporting The electric according .to the present' y invention, comprises an enclosure I having a removable iront cover 2, adapted to bev secured thereto. Two winglike portions 3 and 4 having openings therethrough for the passage of studs are provided upon the enclosure for the ready attachment of the switch at the desired operating point. Ledges 5 and 6 are provided within the enmember I9, with its legs disposed outside the supporting member but having projections thereon cooperating with seats provided in the legs 42 and 43 of the supporting member. The spring 35 serves to definitely bias both the lever 22 and the operator 4I firmly within their respective seats on the supporting member. The extent of pivotal movement of the operating member 4I is defined by the oppositely disposed surfaces 45 and 43 on the legs 23 and 25 of the supporting member. Ari. inwardly directedangell carried by la. leg of A contact carrying or A movable contact 32 is the operating member 4I is adapted to positively engage the lever member 22 to initiate the movement of the parts from the engaged to the disengaged position. This flange, through its ability to positively engage the lever member 22, thereby also serves to force the contacts apart to break any weld which might occur between the contact surfaces. A terminal junction plate 48 is secured tothe back of the base I3 of the enclosure I by a stud 49 and carries the studs 5I and 52 to serve as means for connecting circuit wires thereto, this junction plate being insulated from the other switch parts.

In the operation of the device from .the "on position shown in Figure 1 to the off position shown in Figure 2, the operator 4I moves in a clockwise direction to first bring the flange 41 int?) engagement with the lever member 22 thereby initiating the movement of the lever member 22 and of the switching member 25 carried thereon. Movement;` of the operator moves the operating spring 35 and this tends to move the contact carrier generally vertically, as shown,v the lever 22 pivoting about its mounting or supporting member I9. The movements of both the operator 4I and the lever 22 continue thus until spring 35 is carried through the pivots of lever 22 whereupon the lever quickly snaps to its full open position of Figure 2. The lever 22 is limited in its opposite movements by the engaging of insulating plate 26 with top and bottom walls of the enclosure. -It is to be noted that the attaching of the end of operating spring 35 to the portion 35 of the tongue 33 to place the point of attachment above the plane of the upper surface of lever member 22 and above the horizontal on the stationary contact surfaces while contact pressure' is positively maintained. 'I'his movement continues either through positive engage-- manually or by any exterior means, but the plane through the point of engagement of carriez-25 and lever member 22 when the contacts are engaged will cause the force of the spring $5 to act upon the contact carrier 25 to urge it in 4a. clockwiseA direction about its abutting engagement with the shoulders 3l of the lever member 22. The carrier is prevented from-moving in this direction through the engagement of the movable'contact 32 with the stationary contacts .I'I and I8 so that the force of `thespring 35 urging the clockwise movement of the carrier 2l causes the movable contact 22 to presstightly against the stationary contacts I'I and I8 thereby providing a. very definite contact pressure. This definite contact pressure is maintained while the contact carrier 25 and the movable contact 32 are being moved in a generally vertical direction and until the spring 35 is carried through the pivot point of the lever 22 to thereby shift the direction of the force of the spring 35 to quickly move said lever 22, the contact carrier 25 and the movable contact I2 thereon in a counterclockwise direction.

In the movement of the operating member 5I from the o to the on position, spring 55 is carried inthe reverse direction through the pivots of lever 22 whereupon the carrier 25, contact I2 and lever 22 will be quickly snapped in clockwise direction to the contacts engaged position of Figure 1. In this movement, prior to the snapping action, the carrier 25 will rotate counterclockwise about the shoulders 3| so that proper engagement of contact I2 with the stationary contacts is assured and the possibility of accidental edge contact is prevented. An additional feature of the switch is the relatively large wiping action of the contacts which is secured. In the movement from on" to off, the movable contact will slide for a very appreciable distance switch has shown itself especially adapted for operation by a float in response to changes in liquid level, such as used in the control of sump pump motors and similar liquid level regulators.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto and is to be given its broadest possible interpretion within the terms of the following claims.

What is claimed is:

1. In an electric switch, a stationary contact.

-switching member, .means operative to displace the point of attachment of saidovercenter spring to the switching, member from one side to the other of the pivotal Asupporting element to urge a rotative movement of said switching member relative to said pivotal supporting element before said switching Imember and said pivotal 'supporting yelement are fsnapped to a second position.

2. Inlanelectric switch, a stationaryV contact, a movable contact, a yswitching member movable tomove said movable'contact to engaged 'and disengaged "positions, a fixed supporting `member, a generally U-shapedmember supporting said switching member and. being pivotally mounted on the fixed supportingmember, an

overcenter spring-means secured to said switching member, means operativeito move saidv overcenter spring means to wholly displace the line of action thereof from one side of said U-shaped member to the other side thereof to effect a pivotal movement of said U-shaped member while said U-shaped member is moving between con- .taJcts engaged and disengaged positions, said means including a pivotally mounted operating lever having the legs thereof disposed outside oi' said generally IJ-shaped member.'

3. In an electric switch, a stationary contact, a movable contact, a switching member movable to move said movable contact into and out of engagement with said stationary contacts, a ilxed .supporting member, a' movable supporting member for said switching member pivoted on said fixed supporting member, an overcenter spring means `secured to said switching member, said spring means exerting its bias to maintain said movable supporting member in position upon said iixed supporting membenmeans to move said spring means to effect pivotal movement of said movable supporting member and a generally rectilinear movement of said movable contact face across said stationary contact lface before said spring means passes through the p ivot of said movable supporting member, movement of the spring means through said pivot eifecting snap movement of said movable supporting member and said switching member'from an engaged to a disengaged position.

4. In an electric switch, a stationary contact,

`a movable contact, a switching member movable to move said movable contact into and out of engagement with said stationary contact, a xed supporting member, a generally .U-shaped member supporting said switching member and being pivotally mounted on the xed supporting mem ber, and overcenter spring means secured to said switching member, means operable to move said spring means to effect pivotal movement of said movable supporting member and a generally rectilinear movementl of the movable contact face across the stationary contact face 'before said spring means passes through the pivot of the movable supporting member, movement of the spring means through said pivot eecting snap movement of said movable supporting member and said switching member from an engaged to a disengaged position, said means including a pivotally mounted generally U-shaped operating member having the legs thereof disposed outside of said generally U-shaped supporting meml ber, -v

5. In an electric switch, a stationary -contact, a movable contact, a switching member movable to move said movable contact i-nto engaged and disengaged positions, a pivotal member support# ing said switching member and having. an open-- ingprovided therein, a projection on said switching member extending through said opening when the contacts are in engaged positlon'and moving out of saidopeningwhen said movable contact is moved to disengaged position, means to move said pivotal member and to urge rotative movement of said switching member about its support while said pivotal member isin motion to maintain substantial contact pressure between said stationary and movable contacts until the instant of disengagement, said means including an operating member and spring means interconnecting said operating member and said projection on said switching member.

6. In an electric switch, a stationary contact, a movable contact, a switching member movable to move said movable contact into engaged and disengaged position, a pivotal member supporting said switching member and having an opening provided therein, means carried by said l switching member and oscillatably movable 5 through said opening from one side to the other of said pivotal member, means operative to move said pivotal member and to urge rotative move'- ment of said switchingmember about its suppOrt while said pivotal member is moving to maintain substantial contact pressure between said stationary and movable contacts until the instant of disengagement, said means including an operating member and springmeans interconnecting said operating member and said 'oscillatable' means. Y

'7. -In an electric switch, a stationarycontact, a movable contact, a switching member carrying said movable contact for cooperation with said stationary contact, a pivotal Vmember supporting said switching member and having an opening therethrough, a projection on said switching member extending through said opening means to oscillatably move said projection through said opening `from one side of said pivotal member to the other to eiiect iirst a rotative movement of said switching member about its engagement with the pivotal member and then to eifect a snap movement of said switching 5 member and said pivotal member, said means including an overcenter spring secured to said projection and an operating member for actuating said overcenter spring.

8. In an electric switch, a stationary contact, a

pivotal lever, a contact carrier supported intermediate its ends upon said pivotal lever and at substantially right angles thereto, said contact carrier having a contact surface disposed thereon adjacent one end thereof for cooperation with said stationary contactsl to' make and break an y electrical circuit therethrough, a projecting member provided' on said contact carrier at the opposite end thereof, a pivotal operating member, a spring interconnecting said operating member and said projecting member, an extension on said operating member for movementA thereof, to move the point of attachment of the spring to the projecting member from one side to the other of the point of support"l of said contact carrier on said pivotal supporting member to move said pivotal supporting member and to urge rotative movement of said contact carrier Y about its support while said pivotal member is in I motion to maintain substantial contact pressure 3'0 between the contacts until-said spring means snaps said contact carrier to off position.

9-. Inv an electric switch, a stationary contact, a rst pivotal lever, a second pivotal lever, each of said pivotal levers being movable from one 5 side of the other levers pivot to the other, a contact carrier supported/intermediate its ends upon said iirst pivotal lever, a contact surface disposed upon said contact carrier adapted to cooperate with said stationary contact, a projec- 40 tion' upo'n said contact carrier, and extending from the same side of said contact carrier as said contact surface is disposed, a spring means interconnecting said projection and said second pivotal lever, an extension on said second pivotal lever-whereby said lever may be moved to move the line of'force of said spring means from one side to the other of the plane containing the pivots of said levers to move said projection and actuate said rst pivotal member and urge rotative movement of said switching member about its support whilesaid first pivotal member is moving to maintain substantial contact pressure between said stationary and movable 'contacts until the instant oi' disengagement.

10. In an electric switch, a stationary contact, a support, a pair of oppositely extending pivotal levers mountedthereon, the pivotal axis foreach lever being located on said support intermediate the ends or the other lever, a contact carrier so having a contact surface thereon for cooperation with said stationary contacts and supported upon one of said pivotal levers 'atsubstantially right angles thereto, a projecting member on saidcontact carrier, a spring means interconnecting said projecting member and the second of said pivotal levers. an extension onA said second pivotal lever -for effecting movement thereof to actuate said springmeans. to move said projecting portion from one side of'- a plane containing said pivotal axes' to the other to actuate said first pivotal.

member and to urge rotative 4movement ofsaid switchingmember about its supportwhile, said pivotal member is inmotion.

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