US2239426A - Electric switch - Google Patents

Description

D. G. KIMBALL ELECTRIC swrrcn Filed April 19, 1959 April 22, 1941,

Inventor: Donaid G. Kimball,

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Patented Apr. 22, 1941 ELEQTRIC SWITCH Donald G. Kimball, Stratford, Conn, assignor to General Electric Company, a corporation of New York Application April 19, 1939, Serial No. 268,737

(01. ENG-$) 2 Claims.

My invention relatcs to electric switches, and more particularly to electric switches of the push button type.

It is an object of my invention to provide an improved construction and arrangement in switches of the type described composed of relatively few parts which are easily assembled and manufactured at low cost.

In the accompanying drawing, Fig. l is a view of the switch mounted on an electric range; Figt 2 is a cross-sectional view through the switch showing the interior thereof and the manner in which it is mounted on a support; Fig. 3 is an exploded view showing a sub-assembly of the switch mechanism; Fig. 4 is a perspective View of the switch; Fig. 5 is a perspective View of the switch housing; and Fig. 6 is another cross-sectional view through the switch showing a modified form. of mounting means.

Referring to the drawing, my switch it includes a base member I I made of insulating material, for example, a phenolic condensation product and filler. The base is provided with mounting arms l2 extending from opposite sides thereof and a centrally disposed recess 13 extending from the rear of the base to the front face thereof. In the form of the invention illustrated, I have shown the base and recess as of generally rectangular formation, but it should be manifest that other forms may be employed.

Mounted upon the base and extending into the recess is a switch operating mechanism, shown by Fig. 3. A supporting plate M of insulating material, for example, sheet fiber, is provided with mounting arms 1 5 extending from opposite sides thereof for cooperation with the mounting arms l2 of the base member. Two terminal members it are carried by the plate 44 and each supports a spring contact arm 11. Each terminal member is formed of flat sheet metal lying against the face of the insulating plate and the corresponding terminal members and contact arms are secured to the base by the rivets it. In this manner, the respective contact arms and terminal members are electrically connected to one another. One end of each contact arm is bent inwardly, as shown at 9, for engagement by the rivet I8, in the manner just described, and the other end is formed in a wide loop bend with a contact surface 2| at the end of the bend. The loops 20 extend toward and are biased into engagement with one another so that the contact surfaces 2| interengage, as shown in Fig. 3, to permit a flow of current through the switch. In order to separate the contact surfaces to interrupt the flow of current through the switch, a plunger 22 is provided at one end with a tang 23 of insulating material which passes between the contact surfaces, as shown by Fig. 2. At the other end, the plunger is formed with a handle 24 for operating the switch. A conductor 25 is secured to each of the terminal members 16, for example, by a spot weld 26, and forms part of the switch assembly.

The structure thus far described constitutes a sub-assembly and may be mounted as a unit upon the base It with the insulating plate i4 resting flush against the rear of the base, the contact members resting in the recess 13, and the plunger passing through an opening 21 extending from the face of the base to the bottom of the recess 13. The plunger is provided with an integral flange 28 which engages the wall of the recess and prevents the plunger from falling out of the housing.

At the rear face of the base ll, two grooves 2e are arranged symmetrically on opposite sides of the recess and are of a depth and configuration to receive the terminal members It. The grooves span the recess I3 and the bottoms of the grooves are deepened on opposite sides of the recess, as shown at so, to receive the welded ends of the conductors so that the insulating plate it rests directly against the rear face of the base. A cover plate 3i of insulating material overlies the plate I 4 to protect the exposed ends of the rivets l8 and is of a shape conforming to that of the base. Both the supporting plate l4 and the cover plate 3| are secured to the base by hollow rivets 32 passing through the arms I2 of the base member.

In assembled position, the contact members are completely enclosed Within the base or housing member H and they are supported against lateral or twisting movement by the walls of the recess 13. To move the switch to off position,

the plunger is pressed inwardly to the positionshown by Fig. 2 so that the tang 23 separates the contact surfaces 2!. In this manner the resilient spring contact arms grip the sides of the tang and hold the plunger in depressed position. The end of the tang is beveled to facilitate separation of the contact arms upon depression of the plunger while depression of the plunger is limited by the engagement of the plunger body with the looped portion of the contact arms, as shown by Fig. 2. When the plunger is pulled outwardly, the tang is removed from between the contact arms permitting them to snap together to close a circuit through the switch. Outward movement of the plunger is limited by engagement of the flange 28 with the bottom wall of the recess.

By the construction described, a switch mechanism is to be had which comprises relatively few parts and which may be manufactured and assembled at low cost. Inasmuch as the arrangement of the terminal plates and contact members on the supporting plate is symmetrical, the subassembly comprising the contacts and operating plunger, shown by Fig. 3, may be placed in position either end up upon the base H. This makes for speed of assembly. In addition, the contacts and terminal member are identical in construction and the supporting and cover plates may be punched from a single die. Both the base member II and the plunger 22 are molded of insulating material. This greatly simplifies the production of the switch parts. For ease in connecting up the switch, the conductors 25 may be furnished as part of the assembly.

In order to indicate whether or not the switch is in on or off position, a plurality of lines or indentations 33 are formed around the outer periphery of the plunger immediately adjacent the handle 24. In the form of my invention illustrated, a plurality of indentations are provided which are filled with colored paint. However, it should be manifest that the indicating lines of colored material may be painted on the surface of the plunger. The particular employed may be chosen in accordance with the color scheme of the electrical device with which the switch is to be used. When the switch is off, the plunger is in depressed position and the colored indicating lines or indicia are hidden by the wall of the opening 21. However, when the plunger is moved to extended position the indicating lines are exposed to view forcefully calling the attention of the user to the fact that the switch is on.

One use of the switch is to control a warmer unit of an electric range, but obviously there are many other uses to which the switch may be put. In the illustrated use of the device, shown by Fig. 1, the switch is mounted on the panel 34 of an electric range adjacent a convenience outlet 35. The switch base H is provided with an extension 36 which is adapted to pass through an opening in a mounting panel, in this case the panel 34. In this manner, the body of the switch is hidden behind the range panel and that portion of the switch which is exposed, comprising the extension 36 and operating plunger 22, presents a neat and pleasing appearance on the range panel. The indicating lines 33 stand out prominently against the background of the face extension 36. In the form of the invention illustrated by Figs. 2, 3, 4 and 5, the switch is actually supported upon a sub-panel 31. To this end, screws 38 are slipped through the hollow rivets 32 and fastened to the sub-panel. This provides a strong supporting structure for the switch and one which does not mar the appearance of the front range panel 34.

In the modified form of the invention shown by Fig. 6, a simplified design of mounting means is employed, necessitating only a single supporting bolt. The arms l2 are omitted from the base and a substantially U-shaped bracket 39 is wrapped around the base and held in position by the bent-over tangs 4B which engage the wall of the base. The bracket carries a bolt 4! which is fastened to the sub-panel by the washer 42 and nut 43. This construction has the advantage that the switch base is of smaller size and only a single mounting opening is necessary in the sub-panel. In the modification of Fig. 6, the switch mechanism is constructed as described in connection with the showing of Figs. 2, 3, 4 and 5, the only distinction residing in the form of mounting means employed and the shape of the base member I While in the form of the invention illustrated the conductors 25 have been shown as secured directly to the terminal plates 16, it should be manifest that terminal screws or other securing means may be provided for receiving the bared ends of the conductors.

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

1. In an electric switch, a base of insulating material having a recess therein and an opening extending through the bottom of the recess, a supporting plate of insulating material closing said recess, flexible spring contact arms within the recess, one end of each arm being secured to said insulating plate, the other end of each arm being bent in the form of a loop with the looped end folded back toward the plate to form a contact surface, the contact surfaces thus formed being normally biased into engagement with each other, a plunger within the recess having an insulating projection adapted to be moved between said contact surfaces and a handle extending through said opening, said plunger being provided with means engaging the wall of said recess to limit movement of said plunger as the handle is moved outwardly, inward movement of said plunger being limited by engagement of the plunger with the looped portions of the contact element.

2. In an electric switch, a base of insulating material having a recess therein and an opening extending through the bottom of the recess, the rear face of the base being provided with grooves extending to opposite edges thereof, a supporting plate of insulating material closing said recess, terminal members comprising flat strips of metal mounted on said plate and resting in said grooves, flexible spring contact arms within the recess, one end of each arm being secured to a corresponding terminal member, the other end of each arm being bent in the form of a loop with the looped end folded back toward the plate to form a contact surface, the contact surfaces thus formed extending toward each other and being normally biased into engagement with one another, a plunger within said recess having an insulating portion adapted to be moved between said contact surfaces and a handle extending through said opening, said plunger being provided with means limiting outward movement thereof upon closure of said switch, inward movement of said plunger to open the switch being limited by engagement of the plunger with the looped portions of said contact arms.

DONALD G. KlMBALL.

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