Push button switch with elastic conductive sheet

• US 3,898,421 A
• Filed: 08/16/1973
• Issued: 08/05/1975
• Est. Priority Date: 08/18/1972
• Status: Expired due to Term

• Current Assignee: Masaki Suzumura
• Original Assignee: Masaki Suzumura
• Inventors: Suzumura, Masaki
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Smith, William J.
• Application Number:
  US05/388,827
• Time in Patent Office: 719 Days
• Field of Search: 200/159B,5A,83N,83B,83P,241,243,168G,83Y,83W,67DB
• US Class Current: 200/517
• 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 2203/02 Interspersed fingers
• CPC Class Codes: H01H 2207/01 from bottom to top layer
• CPC Class Codes: H01H 2209/078 Conductive rubber
• CPC Class Codes: H01H 2213/004 Scavenger; Filter
• CPC Class Codes: H01H 2215/008 Part of substrate or membrane

Abstract

There is provided a push button switch using an elastic conductive sheet having a spherical protuberance which is adapted to be deformed by a keytop for electrically connecting fixed electrodes formed on a printed circuit board. Spring means for returning the keytop is not required, so that the construction is simplified. Also, excellent switching action, operability and reliability can be ensured.

Claims

1. A push button switch comprising support means;

a pair of fixed spaced electrodes located on said support means; and

an elastic conductive sheet having a dimple positioned adjacent said electrodes and spaced therefrom by a predetermined distance, said dimple including a central portion and an annular shoulder separated from said central portion by a flexural node, said dimple being deformable with a double snap action when depressed by a force exerted on the central portion thereof, the first snap action of said dimple forcing said annular shoulder into contact with said pair of fixed electrodes thereby making electrical contact therebetween, and the following snap action forcing the central portion of said dimple between said electrodes.

2. A push button switch comprising a printed circuit board;

spaced fixed electrode means printed on said printed circuit board;

an elastic conductive sheet having a dimple positioned adjacent said electrodes and spaced therefrom by a predetermined distance, said dimple including a central portion and an annular shoulder separated from said central portion by a flexural node, said dimple being deformable with a double snap action when depressed by a force exerted on the central portion thereof; and

a keytop slidably supported above said dimple for depressing said dimple, the first snap action of said dimple forcing said annular shoulder into contact with said pair of fixed electrodes thereby making electrical contact therebetween, and the following snap action forcing the central portion of said dimple between said electrodes.

3. The push button switch according to claim 2, which further comprises an insulating member having a hole therein in the position corresponding to said dimple, said insulating member being disposed between said conductive sheet and said printed circuit board.

4. The push button switch according to claim 2, wherein said printed circuit board has a small hole for the escape of air.

5. The push button switch according to claim 2, which further comprises a fibrin filter provided on the underside of said printed circuit board.