Tactile keyboard switch assembly with metallic or elastomeric type conductive contacts on diaphragm support

• US 3,879,586 A
• Filed: 10/31/1973
• Issued: 04/22/1975
• Est. Priority Date: 10/31/1973
• Status: Expired due to Term

• Current Assignee: United Technologies Automotive, Inc. (Lear Corporation)
• Original Assignee: Daniel J. Durocher, Gideon A. Durocher
• Inventors: DuRocher, Gideon A., DuRocher, Daniel J.
• Primary Examiner(s): Scott, James R.
• Application Number:
  US05/411,345
• Time in Patent Office: 538 Days
• Field of Search: 200/1R,5R,5A,83N,86R,86A,159R,159B,262,264,267
• US Class Current: 200/5.00A
• 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 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 13/80 characterised by the manner of cooperation of the contacts, e.g. with both contacts movable or with bounceless contacts
• CPC Class Codes: H01H 2201/004 Wiping action
• CPC Class Codes: H01H 2201/016 Roughened contact surface, e.g. anti-adhering
• CPC Class Codes: H01H 2201/032 Conductive polymer; Rubber
• CPC Class Codes: H01H 2205/014 fixed by mechanical deformation
• CPC Class Codes: H01H 2207/002 Conductive rubber; Zebra
• CPC Class Codes: H01H 2207/01 from bottom to top layer
• CPC Class Codes: H01H 2215/008 Part of substrate or membrane
• CPC Class Codes: H01H 2215/028 alterable
• CPC Class Codes: H01H 2217/01 Off centre actuation
• CPC Class Codes: H01H 2227/014 Conductive particles
• CPC Class Codes: H01H 2229/032 Screw
• CPC Class Codes: H01H 2229/044 Injection moulding
• CPC Class Codes: H01H 2229/058 Curing or vulcanising of rubbers
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

A tactile switch plate for a keyboard comprises a non-conductive member sandwiched between a pair of conductors, the member having a planar body portion provided with a plurality of outwardly deformed carrier portions corresponding in number and spacing to the number and spacing of the keys of the keyboard. Each of the carrier portions is resiliently flexible for movement toward the plane of the body and each carrier portion carries a preferably elastomeric switching member that is adapted to bridge the conductors and establish an electrical circuit between the conductors. The plate and switching members preferably are produced by a molding process and the elastomeric switching members are cured by heat generated by an electrical current.

Claims

1. A switch plate adapted for use in an electrical switch for making and breaking an electrical circuit between a pair of conductors, said switch plate comprising a body having a substantially planar portion surrounding a carrier portion extending outwardly of and to one side of the plane of said body portion;

and a switching member carried by said carrier portion and normally occupying a position spaced from said plane, said carrier portion being formed of a stiff material that is sufficiently resilient to enable said switching member to be moved from its normal position toward said plane, the distance between said plane and said switching member when the latter is in its normal position being such that said carrier portion buckles as said switching member approaches said plane and produces a tactile sensation, and the resilience of the material of said carrier portion constantly tending to restore said switching member to its normal position.

2. A construction according to claim 1 wherein said switching member extends through said carrier portion and is exposed on opposite sides of the latter.

3. A construction according to claim 2 wherein said carrier portion is coniform in configuration.

4. A construction according to claim 3 wherein said switching member is located at the apex of said carrier portion.

5. A construction according to claim 1 wherein said switching member normally is conductive.

6. A construction according to claim 1 wherein said switching member normally is non-conductive and is rendered conductive in response to the application thereto of compressive force.

7. A construction according to claim 1 wherein said switching member comprises a pad of resilient, non-conductive material throughout which is dispersed a plurality of discrete, electrically conductive particles.

8. A construction according to claim 1 wherein said switching member comprises an electrically conductive metallic member.

9. In a key operated device having spaced apart electrical conductors and a plurality of movable, spaced apart operating keys, the combination of a tactile switch plate underlying said keys and comprising a non-conductive, substantially planar body having a plurality of spaced apart carrier portions extending outwardly of and to one side of the plane of said body, the number and spacing of said carrier portions corresponding to the number and spacing of said keys, and a switching member carried by each of said carrier portions adapted to bridge selected ones of said conductors and normally occupying a position spaced from said plane, each of said carrier portions being formed of a still material that is sufficiently resilient to enable the associated switching member to be moved from its normal position toward said plane and into bridging engagement with the selected conductors in response to corresponding movement of the associated key, the distance between said plane and each of said switching members when the latter is in its normal position being such that the associated carrier portion buckles as the switching member approaches said plane and produces a tactile sensation.

10. The construction according to claim 9 wherein the resilience of the material of each of said carrier portions constantly tends to return the latter to its normal position following movement thereof toward the plane of said body.

11. The construction according to claim 9 wherein each of said switching members extends through its associated carrier portion and is exposed on opposite sides of the latter.

12. The construction according to claim 9 wherein each of said carrier portions is coniform in configuration.

13. The construction according to claim 12 wherein each of said switching members is located at the apex of its associated carrier portion.

14. The construction according to claim 9 wherein each of said switching members normally is conductive.

15. The construction according to claim 9 wherein each of said switching members normally is non-conductive and is rendered conductive in response to the application thereto by its associated key of compressive force.

16. The construction according to claim 9 wherein each of said switching members comprises a pad of resilient, non-conductive material throughout which is dispersed a plurality of discrete, electrically conductive particles.

17. A construction according to claim 9 wherein each of said switching members comprises an electrically conductive metallic member.

18. The construction according to claim 9 wherein said body is interposed between said conductors.

19. The construction according to claim 18 wherein at least one of said conductors occupies a position between said keys and said body.