Low profile keyboard switch having panel hinged actuators and cantilevered beam snap acting contacts

• US 4,032,729 A
• Filed: 12/21/1973
• Issued: 06/28/1977
• Est. Priority Date: 12/21/1973
• Status: Expired due to Term

• Current Assignee: Rockwell International Corporation
• Original Assignee: Rockwell International Corporation
• Inventors: Koistinen, Clayton W.
• Primary Examiner(s): Scott, James R.
• Application Number:
  US05/427,173
• Time in Patent Office: 1,285 Days
• Field of Search: 200/1 R, 200/5 R, 200/5 A, 200/6 BA, 200/67 D, 200/67 DA, 200/159 R, 200/159 A, 200/159 B, 200/166 BH, 200/166 J, 200/172 R, 200/275-279 , 200/283, 200/293, 200/302, 200/329-340, 235/145 R, 197/98-103, 340/365, 84/433
• US Class Current: 200/5.00A
• CPC Class Codes: H01H 13/7013 in which the movable contacts of each switch site or of a row of switch sites are formed in a single plate
• CPC Class Codes: H01H 2003/466 using a living hinge to connect the levers
• CPC Class Codes: H01H 2221/016 Lever; Rocker

Abstract

A low profile keyboard switch with tactile feel and short key travel is disclosed. The keyboard may be a matrix connected keyboard and includes a lower, fixed contact and an upper, concave contact. The concave contact is supported at one end and operates as a cantilever beam. When pressure is applied by a key, at the unsupported end to cause buckling of the concave contact at its supported end, electrical contact is made with the lower fixed contact. The concave contacts possess the key return force and the snap action desirable for tactile feel and short key travel for a low-profile, low-cost keyboard switch.

Claims

1. A keyboard switch assembly comprising:

at least one elongated stationary lower contact member;

at least one elongated upper contact member;

said upper contact member having a substantially concave configuration;

a housing including a base member and a cover member;

said cover member engaging said base member;

said base member having at least one groove for securing said lower contact member;

said base member including ridges adjacent each groove for supporting said upper contact member transverse to said lower contact member;

said ridges having indentations along at least one wall thereof;

each upper contact member having at least one movable section which is supported at one end as a cantilevered beam;

said movable section being aligned with an associated indentation; and

key means supported by said cover member for selectively forcing said movable section to buckle at the supported end thereof over the associated indentation and causing the end of said movable section to make electrical contact with said lower contact member.

2. The keyboard switch assembly recited in claim 1 wherein the indentations in said ridges of said base member are graduated and have a substantially concave configuration;

and

said ridges further include holes for receiving support posts on said cover member for engaging said base member and said cover member.

3. The keyboard switch assembly recited in claim 2 wherein said upper contact member includes holes through which said support posts are fitted adjacent said supported end of said movable section in order to secure said upper contact member and to assure said supported end of said movable section is positioned over the edge of the associated indentation.

4. The keyboard switch assembly recited in claim 1 including external electrical circuitry, and conductor means connected from said lower contacts and said upper contacts to said external circuitry.

5. The keyboard switch assembly recited in claim 1 wherein said key means is integrally formed with said cover member in at least one pivotal location.

6. The keyboard switch assembly recited in claim 5 wherein said key means includes:

(a) a plurality of integrally formed keys defined therein, each key having a button portion protruding above the surface of said cover member opposite said cover surface and being separated from the remainder of said cover member around three sides of said button portion, said upper surface of said cover member is generally planar except for said protruding button portions of said keys, and wherein said base member has one lower surface also generally planar, said keys having lower surfaces generally spaced upwardly from said one lower planar surface of said base member and having said depending portions located in the place of said one lower surface of said base member, and each key also having a depending portion for engaging said movable section to make contact with said lower contact member.

(b) an intermediate lower portion of each of said keys integrally formed with each key, the lever portion of each key having a selected thickness and being connected at one end to the button portion of the key and laterally extending from one side of said button portion of said key and,

(c) a self-hinge portion of each of said keys integrally formed with each key, the self-hinge portion of each key having a relatively lesser thickness than said lever portion of said key integrally connecting an opposite end of said lever portion to the remainder of said keyboard member, whereby each key is readily deflected against said movable section to make electrical contact with said lower contact member.

7. The keyboard switch assembly recited in claim 1 wherein said upper contact member has a concave configuration and said lower contact member is substantially flat.

8. The keyboard switch assembly recited in claim 1 including projections from the sidewalls of said groove in said base member for retaining said lower contact member in said groove.

9. The keyboard switch assembly recited in claim 1 comprising

a plurality of said lower contact members arranged in parallel grooves in said base member;

and

a plurality of said upper contact members supported on said ridges in said base member such that said upper and lower contact members are arranged orthogonally to each other to provide a matrix type array.

10. A keyboard switch assembly as recited in claim 8 for selectively actuating said matrix type array, said keyboard switch assembly including:

(a) a locating portion for mounting said cover member in overlying relation to said base member, and

(b) a plurality of integral keys disposed in selected spaced relation to each other, each of said keys being defined by a slit in said member extending around three sides of said key for permitting the key to be deflected for engaging said movable section, each of said keys having a push button portion, a depending portion for engaging said movable section, an integral lever portion of selected length and thickness extending from one side of said push button portion, and a self-hinge portion of relatively lesser thickness than said lever portion integrally connecting said lever portion to the remainder of said member for supporting said key on said member, said push button portions of said keys protruding above said lever portions of said keys for permitting said keys to be uniformly deflected by depressing of said buttons.

11. The keyboard switch assembly recited in claim 1 wherein said indentations are graduated in a plurality of steps and have a relatively concave configuration to mate with the concave configuration of said upper contact member.

12. The keyboard switch assembly recited in claim 1 wherein said upper contact member is fabricated of an electrically conductive material, and

said movable section of said upper contact member comprises a tongue-like member which has one end thereof integrally formed with said upper contact member and three sides thereof separated from said upper contact member so that said movable section remains in a first position until deformed by force applied by said key means.

13. A keyboard switch assembly as recited in claim 1 wherein said key means includes a keyboard member, said keyboard member having a plurality of integral keys each defined by a slit in said member extending around three sides of said key for permitting said key to be deflected, said keys being disposed in selected spaced relation to each other to be engaged with respective contact members for actuating said moveable section when said keys are deflected, each of said keys having a push button portion, a depending portion for engaging said respective contact member, an integral lever portion of selected length and thickness extending from one side of said push button portion, and a self-hinge portion of relatively lesser thickness than said lever portion integrally connecting said lever portion to the remainder of said member for supporting said key on said member, said push button portions of said keys protruding above said lever portions of said keys for permitting said keys to be uniformly deflected by depression of said push buttons.