Push button body for a push-button switch providing snap-action of the switch

• US 3,932,722 A
• Filed: 04/16/1974
• Issued: 01/13/1976
• Est. Priority Date: 04/16/1974
• Status: Expired due to Term

• Current Assignee: Shin-Etsu Polymer Company Limited (Shin-Etsu Chemical Company Limited)
• Original Assignee: Nippo Communication Industrial Company Limited
• Inventors: Saito, Takashi, Obata, Akira
• Primary Examiner(s): Scott, James R.
• Assistant Examiner(s): Smith, William J.
• Application Number:
  US05/461,369
• Time in Patent Office: 637 Days
• Field of Search: 200/302, 200/340, 200/159 B, 200/159 R, 197/98
• US Class Current: 200/513
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 2215/004 Collapsible dome or bubble

Abstract

A push button of rubber or other resilient material for use with a push-button switch and comprising a hollow tilting wall of a mesa shape. The tilting wall of the resilient push button serving as an operating portion is constructed such that its thickness gradually decreases in going from an upper portion toward an intermediate portion and gradually increases in going from the intermediate portion to a lower portion. A curved surface curving inwardly toward the interior of the switch is formed to extend from the intermediate portion to the upper portion. When pressure is first applied to a key top, the curved surface is bent inwardly toward the lower portion of the switch; and when further pressure is applied to the key top, the surface area of the intermediate portion, which is bent inwardly, is increased until the pressure affects the upper portion of the tilting wall. Then, the direction of curving of the curved surface portion is suddenly reversed and the curved surface curves outwardly, whereby the operator can learn by tactile sensation that a switching operation has occurred.

Claims

1. A push-button switch comprising a push-button body of a hollow mesa shape, being of a resilient material, and interposed between a key top and a printed pattern board, said push-button body having an inclined wall consisting of an upper portion, an intermediate portion and a lower portion, said inclined wall having a larger thickness at said upper portion and the thickness of the inclined wall being gradually reduced to a minimum thickness at the intermediate portion, the thickness of said inclined wall gradually increasing from said minimum thickness intermediate portion to a larger thickness lower portion, said upper portion, said intermediate portion and said lower portion being smoothly contiguous with one another.

2. A push-button switch as claimed in claim 1 wherein said intermediate portion of the push-button body of the hollow mesa shape is normally gently curved inwardly toward the interior of the push-button body.

3. A push-button switch as claimed in claim 1 wherein said inclined wall of the hollow mesa shaped body is normally always inclined inwardly upwardly.

4. In a push button switch including:

a board for mounting at least two separated electrodes;

a hollow body of elastomeric insulating material having a base portion in which a substantially cylindrical hollow is provided, a frustoconical-shaped portion integrally formed with said base portion at the edge of the cylindrical hollow, and a top surface portion integrally formed with the frustoconical-shaped portion and extending perpendicular to the common axis of said cylindrical hollow and the frustoconical-shaped portion, said hollow body being mounted on said board with said substantially cylindrical hollow being approximately in registry with said two separated electrodes; and

a conductive member secured to said top surface portion within the hollow of said hollow body so as to face said two electrodes, the improvement comprising

said frustoconical-shaped portion having a minimum thickness portion intermediate of said base portion and said top surface portion in a circumferential direction of the frustoconical-shaped portion, and

the thickness of said frustoconical-shaped portion being gradually increased from said minimum thickness portion to both said top surface portion and said base portion, respectively, such that upon a force exerted on said top surface portion a bending point is developed initially at the minimum thickness portion of the hollow body, and rapidly thereafter two bending points are developed in the frustoconical-shaped portion of the hollow body on opposite sides of said minimum thickness portion, thereby providing a smooth snap-action feel to an operator.

5. In a push button switch including a push button body interposed between a key board top and a printed pattern, said push button body being of a resilient material, and said push button body having a base portion with a circular opening, an inclined wall portion integrally formed with said base portion surrounding said circular opening and a top surface portion integrally formed with said inclined wall portion to form a generally frustoconical-shaped structure with a hollow within said inclined wall portion and said top surface portion, the improvement comprising said inclined wall portion having a thickness being large at said base portion, the thickness of the inclined wall portion gradually decreasing to a minimum thickness intermediate of said base portion and said top surface portion, and said thickness of said inclined wall portion gradually increasing from said minimum thickness to a larger thickness at said top surface portion such that a force exerted by said key top on said top surface portion initially bends the intermediate minimum thickness inclined wall portion inwardly into said hollow, and thereafter provides two bending points in said inclined wall portion on opposite sides of said intermediate minimum thickness inclined wall portion.