US2195312A - Electric switch - Google Patents

Description

March ze, 1940. i. HUT-T 2,195,312

ELECTRIC. swI'rcH v Filed March 4, 1939 Inventor:

Philip Hutt,

'by Jgd/wy His Attofrweg.

Patented Mar. 26, 1940 PATENT OFFICE ELECTRIC SWITCH Philip Hutt, New Haven,

eral Electric Company,

York

Conn., assignor to Gena corporation of New Applicationl March 4, 1939, Serial No. 259,831

9 Claims.

The present invention relates to electric. switches, and more particularly to electric snap switches having a movable contact assembly adapted to oscillate from one circuit-controlling 6 position to another. l

It is an object of this invention to provide an improved movable contact assembly for a switch of this type which is durable in use and economical to manufacture.

It is another object of this invention to provide a novel contact structure which may be assembled easily on a blade carrier Without additional fastening means.

Further objects and advantages of the present invention will become apparent as the following description proceeds, reference being had to the accompanying drawing, in which Fig. 1 is a plan view of an electric switch embodying the present invention; Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1; Fig. 3 is a sectional view taken along the lines 3-3 of Fig. 1; Fig. 4 is a view of the interior of the switch of Fig. 1 with a portion of the switch mechanism removed; Fig. is an exploded view of a movable contact assembly embodying the present invention, and Fig. 6 is an exploded view of a modied form of the contact structure.

Referring to the drawing, a casing II) of suitable insulating material, such as a molded phenolic condensation product, is recessed from one face to receive the switch mechanism. The opposite side walls of the casing are provided with thickened portions II in which are formed suitable slots or bearing surfaces l2. The slots are formed in alignment and are open at their upper ends to receive the laterally extending trunnions I3 of a substantially Ushaped contact carrier I4 which is adapted to oscillate with respect to the switch casing about an axis passing through tending substantially normal to its axis of oscillation are the movable contact structures designated generally by numeral I5 which are adapted to cooperate with xed contacts secured at opposite 45 ends of the casing to control the electric circuits through the switch. Although not limited there-- to, I have illustrated my invention in connection with a three-way switch having fixed contacts I6 and l1 formed integrally with terminals I8 and 50 I9 respectively and secured in one end of the casing by suitable screws 20. At the other end of the casing fixed contacts 2l and 22 and the terminal 23 are formed from a single stamping of conducting material and are secured to the cas- 55 ing by a screw 24. As illustrated in the drawing the trunnions. Mounted on the carrier and ex- (Cl. o-67) the fixed contacts IB and 22 are positioned nearthe top of the casing and the contacts I'I and 2| near the bottom of the casing, so that with the contact carrier in the position shown in Figs. 3 and 4 an electric circuit is completed from terminal I9 to terminal 23 through contacts I1 and 22 and when the carrier is tilted toits other circuitcontrolling position a circuit is completed from terminal I8 to terminal 23 through the contacts I6 and 2l. lo

An operating mechanism for the movable contact assembly is provided by a toggle lever 25 and an over-center compression spring 26. The toggle lever is pivotally mounted in an opening 21 of a mounting strap 28 by a pin 29 which extends through aligned openings formed in the anges 30 depending from the opposite edges of the mounting strap. The over-center spring is positioned at one end on the blade carrier by an integral projection 3| and is operatively connected at the other end with the inner end of a metallic insert 32 of the toggle lever 25. With this arrangement the compression spring is effective to hold the blade carrier assembled in the casing with the trunnion positioned in the slots I2. A sheet of insulating material 33 which forms a closure for the casing is held between the ends of the pin 29 and the under side of the mounting strap 28 which is secured to the top of the switch casing by suitable bolts 34. With the construction thus far described it is apparent that pivotal movement of the toggle lever 25 is effective to oscillate the contact carrier and its associated contacts from one circuit-controlling position to another with a snap action. The Walls of the slots I2 extend divergently upward from a rounded bottom portion and cooperate with the straight sides of the trunnions to limit the movement of the contact carrier relative to the casing.

In accordance with the present invention a simplified movable contact assembly is provided. Referring now to Fig. 5, each of the movable contact structures I5 comprises a U-shaped gripping member 35 and a pair of contact blades 36, which are preferably of the lidentical construction and stamped from suitable sheet metal conducting material. Each of the bladesis formed with a contact portion 31 at either end and at its central portion with a recess 38 opening on one edge of the blade. The contact blades are arranged on opposite sides of the U-shaped gripping member with the recesses 38 in alignment with the open portion of thc U-shaped member and are secured thereto in any suitable manner. In the particular construction shown in Fig. 5 the blades are spot welded to the arms of the gripping memvber at the four points indicated by numeral 39.

Theinner edges of the arms of the U-shaped gripping member 31 are substantially parallel and are provided with serrations which extend slightly beyond the side walls of the recesses 38 of the contact blades. A U-shaped-groove 4| is formed in each leg 42 oi' the contact carrierfor the reception of the walls of the recessed central portion of the contact structure. The arm portions 43 of the groove are formed in alignment on the opposite faces ol.' the carrier.

In assembling the 'contact structure on the carrier the onen edge of the contact structure is slipped over the lower edge of the carrier with the walls of the contactU structure received between the side walls of the groove 4|. The contact structure is then pressed onto the carrier until the base of the U-shaped gripping member abuts the bottom of the wall of a portion of the groove 4|. The serrations 40 of the gripping member bite into the bottom wall of the arm portions 43 of the groove and prevent the contact structure from sliding off the carrier during operation of the switch. The arms of the U- shaped member are resilient and aid in maintaining the frictional engagement with carrier. The side walls of the groove 4| effectively position the contact structure and prevent its lateral displacement.

In Fig. 6 a modified stationary contact structure is illustrated which is very similar to that just described. In this modification the contact blades 36 are provided with integrally formed inturned flanges 44, each of which extends from the inner face of one of the contacts an amount equal to half the thickness of the gripping member 38. As shown in Fig. 3 these iianges are arranged to engage the inner surface 45 of the base of the U-shaped gripping member so that they are clamped against the bottom surface of the groove 4|. As before the serrated portions 40 of the gripping member engage the bottom Walls of the aligned arms 42 of the groove 4| and prevent the contact structure from slipping from the carrier.

By utilizing a contact carrier of insulating material it is possible to mount the movable contact structure without the use of insulating washers and bushings and, in this way, the number of parts required is materially reduced. The presen t invention provides a very simple and inexpensive yet very effectiveA construction for utilizing a contact carrier of insulating material in an electric snap switch.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. In an electric switch, a casing, fixed contacts secured to said casing, a contact carrier of insulating material mounted for oscillating movement with respect to said casing, a movable contact structure adapted to connect certain of said fixed contacts in one position of said carrier, said contact structure having a contact portion at either end and a central portion recessed from one edge thereof, the opposite side walls of said recess being substantially parallel, said movable contact structure being positioned on said contact carrier with said side walls in frictional engagement with opposed surfaces on said carrier, and means on said insulating carrier for preventing lateral displacement of said contact structure.

2. A movable contact assembly for an electric switch comprising a contact carrier of insulating material adapted to be mounted for oscillating movement with respect to a switch casing and having aligned grooves formed in opposite faces thereof and a movable contact structure having a central portion recessed from one edge thereoi', the opposite side wallsy of said recess being substantially parallel and provided with serrations. said movable contact structure being positioned Ion said contact carrier with said side walls in said grooves and with said serrations in biting engagement with the bottom walls of said grooves.

3. A movable contact assembly for an electric switch comprising a Vcontact carrier adapted to be mounted for oscillating movement with respect to a switch casing, a movable contact structure having a central portion recessed from one edge thereof, the opposite side walls of said recess being substantially parallel and provided with serrations, said movable contact structure being positioned on said contact carrier with said serrations in biting engagement with opposed surfaces on said carrier, and means on said carrier for preventing lateral movement of said contact structure.

4. A movable contact assembly for an electric switch comprising in combination a contact carrier of insulating material and a contact structure, said contact structure comprising a U- shaped gripping member having serrations formed on the inner edge of the opposed arms thereof, a pair of contact'blades having a central portion recessed from one edge, said blades being welded to the opposite faces of said U-shaped member with said recesses in alignment with the open portion of said U-shaped member, said contact structure being positioned on said carrier with the serrated edges of said U-shaped member in biting engagement with opposed surfaces on said carrier.

5. 'A movable contact assembly for an electric switch comprising in combination a contact carrier of insulating material and a contact structure carried thereby, said contact structure comprising a U-shaped gripping member and a contact blade recessed from one edge, said blade being secured to one face of said gripping member with said recess in alignment with the open portion of said U-shaped member, said contact .structure being positioned on said carrier with the opposed arms of said U-shaped member in frictional engagement with opposed surfaces on said insulating carrier.

6. A movable contact assembly for an electric vswitch-comprising a substantially U-shaped contact carrier having laterally extending trunnions adapted to mount said carrier for oscillating movement with respect to a switch casing and a contact structure having a central portion recessed from one edge thereof, said contact carrier having aligned grooves formed inthe opposite side Walls of one armv thereof, said lcontact structure being positioned on said arm with the opposite walls of said recess positioned in said grooves and frictionally engaging the walls thereof to hold said contact structure on said carrier.

7. A movable contact assembly for an electric switch comprising in combination, a substantially U-shaped contact carrier of insulating material having laterally extending trunnions adapted to mount said carrier for oscillating movement with respect to a switch casing and a contact structure mounted on said carrier and extending in a direction normal to the axis of oscillation of said carrier, said contact structure comprising a con- 7g tact blade having a contact portion at either end and a central portion recessed from one edge thereof, means secured to said blade and extending along the opposite side walls of said recess, the edges of said means adjacent said recess being provided with serrations, said contact structure being positioned on said one arm of said contact carrier with the serrated edges of said means in biting engagement with opposed surfaces on one arm of said U-shaped carrier.

8. A movable contact assembly for an electric switch comprising in combination, a substantially U-shaped contact carrier of insulating material having laterally extending trunnions adapted to mount said carrier for oscillating movement with respect to a switch casing and a contact structure mounted on said carrier and extending in a. direction normal to the axis of oscillation of said carrier, said contact structure comprising a U-shaped gripping member having serrations formed on the inner edge of the opposed arms thereof, a pair of contact blades having a contact portion at either end and a central portion recessed from one edge thereof, said blades being secured to said U-shaped gripping member with said recesses in alignment with the open portion of said U-shaped srippins member, said U- opposite faces of shaped contact carrier having aligned grooves on serrated edges of said U-shaped gripping member in biting. engagement with the bottom walls of said grooves.

9. A movable contact assembly forv an electric switch comprising in combination a blade carrier of insulating material' and a contact structure, said contact structure comprising a U- shaped gripping means having the inner edge of each a'rm thereof provided with serrations, a pair of contact blades each recessed from one edge and having a flange portion adjacentthe bottom wall of said recess extending normally to the plane of said contact blades, said blades being arranged on opposite sides of said gripping means with said flanges in engagement with the inner edge of the base of said U-shaped member, said blade carrier having a groove formed in three sides thereof, said contact structure being positioned in said groove with said iiange portions clamped against the bottom wall of a portion of said groove and with said serrations in biting engagement with the bottom walls of other portions of said groove.

one arm thereof, said contactstructure being positioned on said arm with the

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