US2575147A - Electric switch - Google Patents

Description

Nov. 13, 1951 T, UNSWOR'TH 2,575,147

ELECTRIC SWITCH Filed June a, 1949 2 SHEETS- SHEET 1 T. UNSWORTH ELECTRIC SWITCH Nov. 13, 195] 2 SHEETS-SHEET 2 Filed June 8, 1949 Patented Nov. 13, 195i ELECTRIC SWITCH VThomas Unsworth, Wellesley, Mass., assignor to Cole-Hersee Company, Boston, Mass., a corporation of Massachusetts Application June 8, 1949, Serial No. 97,777

Claims. i l

This invention relates to electric switches, and pertains more particularly to improvements in automotive switches or the push-pull type adapted for use in an electric lighting circuit, or other circuits, of an automobile.

The principal purpose of the invention is to provide a push-pull switch which is simple and economical to manufacture, easy to assemble and durable and eflicient in mechanical and electrical operation. More particularly, it is an object of this invention to provide a switch of this type having a flat-formed resilient saddle member, removably and rotatably connected to the operating shaft or plunger, constituting a Contact supporting element and functioning as a spring vto apply equal contact pressure and positive contact location, free from manual torque or strain on the operating shaft, at each position of the switch.

Additional features and advantages of the invention will be apparent from the following description of a recommended embodiment thereof, shown in the accompanying drawings, and

k will-be pointed out in the appended claims. It

will be understood, however, that the structural details of the'switch herein illustrated and described niay be varied to suit particular conditions oi' use, without departing from the essence of'this invention as set forth in said claims. 'In the drawings,

' Fig. 1 is a plan View of a push-pull switch made lin accordance with this invention;

Fig. 2 is a side elevation of the switch;

Fig. 3 is an end view looking to the left of Fig. l;

Fig. 4 is ari enlarged section on line 4-4 Vof Fig. 1?

j Fig. 5 is a transverse section on line .5 5 of FigE 4;

Fig. 6 is a composite View of the switch in the position of Fig. 1, but with its insulating cover plate removed and shown in reversed position; .and

Fig. 7 is an exploded view showing various separable elements of the switch, in perspective. In lthe particular embodiment chosen for the purpose of illustration, the improved push-pull switch is of the multi-pole and multi-throw type, having one inoperative and two operative positions, but it will be apparent that the switch rmay be of the single pole and single throw type, or any combination of these types. The illustrated switch is manually controlled in both directions of movement of the operating shaft or plunger; but it will be understood that it may be of the spring-loaded plunger type which is soif-returning, in one direction or tne other.

y',l'he switch comprises a ocx-line metal casing l I which inay be iormed or sneet nietai, or otherwise, and which nas an open top provided with marginal tongues iz for retaining tiie cover piate it and its associated eieiiients ori tne top or the case. rlne cover piate may consist oi a laminated norous or plastic insulator, provided on its inner side ilrig. o) with tWo pairs or' side button contacts I4 and la, respectiveiy, and two center contacts lo and' l, respectiveiy, and with ernbossed buttons it and It', formed oi the insuiatirig material, to ensure a straight line wiping action oi the sliding contact meiiioer hereinaiter described.

ih-e `outer side of the insulating plate carries terminals It and I8 Ifor the contacts :o and I5, respectively, at one side of the plate; a common termi-nal IS for the contacts lll and i5 adyacent the other side of the piate and a common terminal 2U for the center contacts iii and l5. rl'he base may also carry a fuse 2i between the terminal 2U and a lead-in terminal 22. The construction and arrangement of the terminals and fuse connections are not, however, material to the present invention.

One end oi the switch box or casing Il, which may be formed by the inwardly directed ilanges 23 of the casing sides and an interior plate (Fig. .6) lis fitted with a threaded bushing 2,5 .carrying nuts 26 for attaching the switch to the instrument panel oi other structural part .of the vehicle, and receiving the slidabie operating shaft 2l. The outer end of the shaft has an operating knob 28 which may be threaded thereon or otherwise attached thereto.

The inner end of the operating shaft 2l is slidable axially within the casing Il, and is provided with one or more pairs of side notches 29 for Yremovably receiving a slotted thrust plate or spacer 30, the edges of which have sliding relation with the interior surfaces of the casing. The top edge of the plate 3B is preferably provided with marginal points or projections 3i (Fig. 7) which bear on the inner surface of the insulating plate I3, so that the central portion of said edge clears the contact and insulating Abuttons on the inner side of the insulating meinber. The plate 3B constitutes a stop engageable Vwith the -end piece of the casing to limit outward movement of the shaft. The plate may lbe disposed in the dotted line position of Fig. 4, if it is desired to shorten the shaft movement to provide but one operative position of the switch.

The extreme inner end of the shaft 21 has an annular groove 32 which removably receives a slotted portion 33 of the sliding, resilient contact supporting element 34. The sliding support or carrier 34 consists of a strip of fiat-formed spring metal bent to form a saddle, substantially U- shaped in longitudinal section and providing a bottom plate 35, a top plate 36 and an integral connecting web or end portion 31. The web is slotted at 33, as aforesaid, the slot extending from top to bottom of said end portion, and one end of the slot being sufficiently wide to receive the tip 33 of the shaft 21 when the slotted end of the saddle is removably and rotatably tted into the groove 32.

The bottom plate 35 of the saddle bears slidably against the bottom wall 39 of the casing II, and said parts preferably have complemental recesses and projections, as indicated at 4D (Fig. 4), for releasably holding the contact in each of the adjusted positions of the switch. The free end of said plate is engageable with the adjacent end wall of the casing, to limit inward movement of the shaft. The top plate 36 of the saddle is spaced from the insulating plate I3, and carries and extruded, eyelet-like projection 4I which is loosely received in a central aperture 42 of a ilat insulator piece 43, removably fitted on the saddle plate 36.

The top face of the insulator 43 carries a substantially Y-shaped, bridging conductor 44, formed with three upstanding contact points including a pair of complemental contacts 45, at the end portions of the arms of the Y-shaped piece, and a contact 46 at the stem of said piece. The extreme ends of the strip forming the conductor 44 are bent transversely at 41 and 48 and provide locating tabs which are received in the notches 49 and 50, respectively, of the insulator 43 (Fig. 7), so that said conductor is supported in operative position during movement of the spring saddle 34. The pair of contacts 45 have sliding engagement with the respective pairs of contact buttons I4 and l5 and the pair of insulated buttons I 6; and the contact 46 has sliding engagement with the contact buttons I4' and I5' and the insulated button I6', respectively, in the selected positions of the switch. The spring saddle ensures adequate pressure contact at each of said positions, and the provision of the embossed, insulated buttons in association with the projecting contact buttons on the cover plate I3 ensures equal contact pressure in all positions of the switch, as aforesaid.

By providing a loose, slidable and rotatable connection between the spring saddle 34 and the end of the operating arm 21, instead of a rigid or fixed connection at that point, any manual torque or strain on the operating shaft is not transmitted to the saddle or the conductor and contacts carried thereby. The provision of the thrust plate 30, as a separate guide for sliding movement of the inner end of the operating shaft, further assists in avoiding the transmittal of torque or strain from the shaft to the spring saddle 34 or conductor 44.

The operation of the switch will be evident from the foregoing description. -In the off position, the shaft or plunger is pushed inwardly, and the saddle and contact member assume the position shown in the drawings. In this position, the contacts 45 engage the insulated buttons I6, and the contact 46 engages the center insulated button I6'. When the plunger is pulled outwardly to the rst operative position, the contacts 45 engage the button contacts I4, and the contact 46 engages the button contact I4'. When the shaft is pulled further to its second operative position, the contacts 45 engage the button contacts I5, and the contact 46 engages the button contact I5'. As previously stated, the novel features of this invention may be embodied in a single-pole, single throw switch, as well as in a double-pole, double throw switch, as herein described; and it is evident that the improved construction may be utilized for any purpose for which a push-pull switch of this type is suitable.

Each of the elements carried by the operating shaft and movable therewith, are separably associated, so that the parts can be manufactured simply and economically and may be readily assembled in the switch casing, after the operating shaft has been installed.

I claim:

1. A push-pull switch comprising a casing having a bottom, sides and ends, a cover plate of insulating material removably attached to the top of the casing, said cover plate having terminals on its outer side and complemental contacts on its inner side, a shaft mounted in one end of the casing for sliding movement longitudinally thereof, a spring metal saddle slidable longitudinally within the casing and having a bottom portion slidably engaging the casing bottom, an integral end portion and an integral, flexible, and resilient top portion disposed substantially in spaced parallel relation to said cover plate, means comprising a slot extending from top to bottom of said end portion for removably and rotatably connecting said saddle to the inner end of said shaft, an insulator on the toppertion of said saddle, and a bridging conductor on said insulator, said conductor having contacts slidably engageable with complemental contacts on said cover plate.

2. A push-pull switch comprising a casing having a bottom, sides and ends, a cover plate of 1 insulating material removably attached to the top of the casing, said cover plate having terminals on its outer sides and complemental contacts on its inner side, a shaft mounted in one end of the casing for sliding movement longitudinally thereof, a spring metal saddle slidable longitudinally within the casing and having a bottom portion slidably engaging the casing bottom, an integral end portion and an integral, flexible, and resilient top portion disposed substantially in spaced parallel relation to said cover plate, means comprising a slot extending from top to bottom of said end portion for removably and rotatably connecting said saddle to the inner end of said shaft, an insulator on the top portion of said saddle, and a bridging conductor on said insulator, said conductor having contacts slidably engageable with complemental contacts on said cover plate, and a thrust plate disposed transversely within the casing and removably connected to said shaft forr guiding the movement of the shaft and limiting outward movement thereof. Y

3. A push-pull switch comprising a casing having a bottom, sides and ends, a cover plate of insulating material removably attached to the top of the casing, said cover plate having terminals on its outer side and complemental contacts on its inner side, a shaft mounted in one end of the casing for sliding movement longitudinally thereof, a spring metal saddle slidable longitudinally within the casing and having a bottom portion slidably engaging the casing bottom, an integral.

end portion and integral, exible, and resilient top portion normally disposed in spaced parallel relation to said cover plate, means comprising a slot extending from top to bottom of said end portion for removably and rotatably connecting said saddle to the inner end of said shaft, an insulator on the top portion of said saddle, and a bridging conductor removably applied to the exposed surface of said insulator, said conductor having contacts slidably engageable with complemental contacts on said cover plate, and having locating tabs engageable with the edges of said insulator.

1. A push-pull switch comprising a casing having a bottom, sides and ends, a cover plate of insulating material removably attached to the top of the casing, said cover plate having terminals on its outer sides and complemental contacts on its inner side, a shaft mounted in one end of the casing for sliding movement longitudinally thereof, a spring metal saddle slidable longitudinally within the casing and having a bottom portion slidably engaging the casing bottom, an integral end portion and an integral, exible, and resilient top portion normally disposed in spaced parallel relation to said cover plate, means comprising a slot extending from top to bottom of said end portion for removably and rotatably connecting said saddle to the inner end of said shaft, an insulator on the top portion of said saddle, and a bridging conductor on said insulator, said conductor having contacts slidably engagea'ble with complemental contacts on said cover plate, the bottom portion of the saddle having an extruded projection, and said insulator having an opening therethrough receiving said projection for loosely and removably interconnecting said parts.

5. A push-pull switch comprising a casing having a bottom, sides and ends, a cover plate of insulating material removably attached to the top of the casing, said cover plate having terminals on its outer side and complemental contacts on its inner side, a shaft mounted in one end of the casing for sliding movement longitudinally thereci, a spring metal saddle slidable longitudinally within the casing and having a bottom portion slidably engaging the casing bottom, an integral end portion and an integral, ilexible, and resilient top portion normally disposed in spaced parallel relation to said cover plate, means comprising a slot extending from top to bottom of said end portion for removably and rotatably connecting said saddle to the inner end of said shaft, an insulator on the top portion of said saddle, and a bridging conductor removably applied to the top surface of said insulator, said conductor having contacts slidably engageable with complemental contacts on said cover plate and having locating tabs engageable with the edges of said insulator, and a slotted thrust plate disposed transversely within the casing and connected to said shaft for guiding the movement of the shaft and limiting out'- ward movement thereof, said shaft having notches removably receiving the slotted plate, the top portion of said saddle having an extruded projection and said insulator having an opening therethrough receiving said projection for loosely and removably interconnecting said parts.

THOMAS UNSWORTH.

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

UNITED STATES PATENTS Number Name Date 1,906,085 Norviel Apr. 25, 1933 2,323,050 Johnson June 29, 1943 2,346,311 Johnson Apr. 11, 1944 2,380,933 Bolley et al. Aug. 7, 1945

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