US2391238A - Snap switch - Google Patents

Description

Dec. 18, 1945. J HORMAN 2,39L23 SNAP SWITCH Filed March 27, 1945 2 Sheets-Sheet 1 I n n. IL/717 HM. "M I IINVENTOR ATTORNEYS Dec. 18, 1945. .1. H. HORMAN 2,391,233

5m? SWITCH Filed March 27, 1943 2 Sheets-Sheet 2 51 Hu /J in, Q

INVENTOR MMM ATTO R N E YS Patented Dec. 18, 1945 SNAP SWITCH John H. Horman, Tuckahoe, N. Y., assignor, by

mesne assignments, to Allied Control Company, Inc., New York, N. Y., a corporation of New York A Application March 27, 1943, Serial No. 480,743

2 Claims.

This invention relates to snap switches of the type illustrated in Patent No. 2,355,951 to John M. Coffeen, issued August 15, 1944.

Such a switch comprises a hollow body member in which is supported a diaphragm having a snap action in two directions and normally flexe d to a position at one side of its neutral point and exerting a continuous reaction to return thereto when moved to a position at the other side of its neutral point. An operating member for the diaphragm has a portion extending through the wall of said body to be accessible from the exterior. Within the body are one or more stationary contacts and the diaphragm carries a like number of contacts for co-operation with the stationary contacts to close a circuit. The movable contacts engage the stationary contacts when the diaphragm is in its normal position and are disengaged therefrom when the diaphragm is flexed to its other position. The movable contacts are mounted on a plate carried by a rigid stud attached to the diaphragm. Any adjustment of the movable contacts has to be effected by bending the supporting plate prior to final assembly of the switch elements within the body. It is therefore often diflicult to obtain proper spacing between the stationary contacts and the movable contacts in the flexed position of the diaphragm and often requires several trial assemblies prior to final assembly. Unless proper spacing of the contacts in this position is accomplished, the life of the contacts and consequently the life of the switch is materially reduced.

An object oi this invention is a switch of the I type above referred to of such structure and arrangement that the relationship of the movable contacts to the diaphragm and. therefore, to the stationary contacts when the diaphragm is in its flexed position, may be adjusted after the switch elements have been assembled in .the body.

According to the present invention, the support for the'movable contacts is adjustably attached to the diaphragm by means including a nut and the body 0r casing is provided with an' following specification and accompanying drawings, wherein:

Fig. 1 is a plan view of a switch embodying the invention;

Fig. 2 is a section on the line 22 of Fig. 1 with the diaphragm in normal ponition;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a view similar to Fi 2 with the diaphragm flexed, and

Fig. 5 is a section on the line 5-5 of Fig. 3.

The casing or body I0 is formed of a pair of recessed members II and I2 composed of moldable insulating material such, for example, as Bakelite. The two portions are held together by bolts |3 or other suitable means and between the meeting edges of the two members are received the rim of a flexible diaphragm M and an annular gasket I5. The diaphragm l4 divides the interior of the casing into two chambers and the gasket l5 provides a seal for the lower chamber. The inner portion of the diaphragm It provides a snap action in two directions, that is, it resiliently urges its center to the fully-retracted position shown in Fig. 2 with a major force. Only when an external force greater than said major force operates on the diaphragm can the center of the diaphragm be moved from its retracted position past a neutral point. When the center is moved past a neutral position, the center is resiliently urged by the stored energy of said diaphragm to an advanced position with a minor force. However When the center is in the neutral and/or the advanced position, the major force operates to urge said center to return to the retracted position. As soon as the superior external force is removed, the major force operates to return the center to its retracted position. The major and minor forces are stored within the diaphragm itself which is so prepared as to inherently possess the desired resilient characteristics.

Stationary electrical contacts I6 and i! are electrically connected to bus bars I8 and 9 by means of rivets 20 and plates 2|. A conductor 22 carries movable contacts 23 and 24 which are normally pressed against the stationary contacts. Thus, when the switch is normally closed, it is efiective to normally pass electrical current from the bus bar I8 through the rivet 20, plate 2|, stationary contact l6, movable contact 23, plate 22, movable contact 24, stationary contact plate 2| and rivet 20 to the bus bar 9. The switch may be used to close a circuit adapted to be opened by an external force. An actuator 25 is provided for moving the inner portion of the diaphragm H. The actuator may be in the form of a Bakel l l lite recessed button secured to a metal stem 2t extending through an opening 21 in the casing II). In the operation of the switch, the stem 26 is depressed from the position shown in Fig. 2 to the position shown in Fig. 4, thereby causing the actuator 25 to move the diaphragm from the position shown in Fig. 2 to the position shown in Fig. 4. The diaphragm is depressed with a snap action and is maintained in an advanced position beyond its neutral point with a minor force.

A U-shaped member 28 is attached to the diaphragm I4 by a bolt 29 passing through the diaphragm and the bight of the U in co-operation with a nut 30. The end of each leg of the U 28 is reduced to form a tongue 3| which is slidably received in a slot 32 in the plate 22. The bolt 29 extends through the plate 22 and an expansion spring helix 33 is interposed between the bight of the U member 28 and the plate 22. A nut 34 is threaded on the end of the bolt 29 and limits movement of the plate 22 under the influence of the spring 33. By rotation of the nut 35. the plate 22 is either drawn toward the diaphragm against the action of the spring 33 or is moved away from the diaphragm by the action of the spring 33. By rotation of the nut 34, the relationship between the stationary contact I1 and the movable contacts 24 in the flexed position of the diaphragms may be adjusted.

In order to permit adjustment of the movable contacts after the switch mechanism has been assembled in the casing, an aperture 35 is provided in the casing wall in alinement with the bolt 29 and nut 36, this aperture being of sufficient area to permit the insertion of a socket wrench capable of receiving the nut 34. After adjustment of the movable contacts by rotation of the nut 34 and removal of the tool, the aperture 35 is closed by a suitable plug 36 preferably composed of the same material as the casing.

I claim:

1. In an electric switch, a stationary support, a movable support, a threaded bolt carried by one support, a U-shaped element having its bight contacting said support and having a bight opening through which said bolt extends, means on said bolt attaching said U element. to said support, a first contact member slidably connected to the leg ends of said U-shaped element, an expansion spring interposed between said first contact member and the bight of said U-shaped element, a nut threaded on said bolt and engaging said first contact member to limit movement thereof away from said one support, and a second contact member carried by the other support.

2. In an electric switch, a stationary support, a movable support, a threaded bolt carried by said movable support, a U-shaped element having its bight contacting said support and having a bight

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