Thin keyboard having torsion bar keyswitch hinge members

• US 6,005,209 A
• Filed: 11/24/1997
• Issued: 12/21/1999
• Est. Priority Date: 11/24/1997
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Pai, Derek Solomon, Eisbach, Christopher Karl, Dyer, William Marvin, Selker, Edwin Joseph, Burleson, Winslow Scott
• Primary Examiner(s): FRIEDHOFER, MICHAEL A
• Application Number:
  US08/979,341
• Time in Patent Office: 757 Days
• Field of Search: 200/5 R, 200/5 A, 200/511-517, 200/341-345, 400/472, 400/490, 400/491, 400/495, 400/495.1, 400/496
• US Class Current: 200/343
• CPC Class Codes: H01H 13/705 characterised by construction, mounting or arrangement of operating parts, e.g. push-buttons or keys
• CPC Class Codes: H01H 2221/004 U-shaped openings surrounding keys
• CPC Class Codes: H01H 2221/044 Elastic part on actuator or casing

Abstract

A keyboard apparatus is provided for small and lightweight computers and the like. Keyswitches and a keyboard assembly comprise a sheet member having a plurality of key faces fixed thereon in a conventional keyboard arrangement. A plurality of cutouts are provided in the sheet member, partially surrounding each key face. A living hinge member is provided in the sheet member at one side of each key face. Each living hinge member includes a base section, an intermediate section, and a key face section. The former two and the latter two sections each interface at a living hinge. Depressing the key face causes the key face section to pivot about the living hinges to operate a corresponding set of electrical contacts, indicating operation of the key. A conventional rubber spring may transmit the pivot motion of the key face to the electrical contacts. The living hinges are made to have a greater resilience and flexibility than those of the sections, such as by scoring, scribing, perforation, or other suitable treatment. Accordingly, the intermediate section is able to serve as a torsion bar, advantageously limiting the key'"'"'s freedom to twist under the user'"'"'s finger pressulr.

Claims

1. A keyswitch assembly comprising:

electrical contact members having normally separated contacts, which make electrical contact when the keyswitch assembly is vertically compressed; and

a thin sheet of resilient material having a cutout hinge member, the hinge member pivotable about first and second horizontal axes intersecting the hinge member, the hinge member having a first resiliency, the hinge member including a base section and an intermediate section which interface at a first living hinge along the first axis, the hinge member further including a key section supporting a key face affixed thereon, said key section interfacing with the intermediate section at a second living hinge along the second axis, the first and second living hinges having a second resiliency which is greater than the first resiliency, wherein the base section defines a first plane and the key section defines a second plane substantially parallel to said first plane when said hinge member is in a quiescent condition, said intermediate section defining a third plane traverse to said first plane and said second plane when the hinge member is in said quiescent condition;

whereby, when the key face is pressed, the hinge member pivots about the first and second axes to make the electrical contact between the electrical contact members, and the intermediate section acts as a torsion bar to restrain the key face from twisting when pressed.

2. A keyswitch assembly as recited in claim 1, wherein the first and second living hinges have a chemical makeup, as a result of one of (i) optical treatment, (ii) chemical treatment, and (iii) thermal treatment, which results in the second resiliency.

3. A keyswitch assembly as recited in claim 1, wherein the hinge member has perforations at the first and second living hinges.

4. A keyswitch assembly as recited in claim 3, wherein the perforations are evenly spaced along the first and second living hinges.

5. A keyswitch assembly as recited in claim 3, wherein the perforations are circular.

6. A keyswitch assembly as recited in claim 3, wherein the perforations include perforations elongated along the first and second axes.

7. A keyswitch assembly as recited in claim 3, wherein the perforations include a combination of generally regular perforations and perforations elongated along the first and second axes.

8. A keyswitch assembly as recited in claim 7, wherein:

the living hinges each have ends and a middle; and

the perforations include generally regular perforations near the ends of the first and second axes, and elongated perforations near the middles of the first and second axes.

9. A method for producing a keyswitch assembly from a thin sheet of resilient material having a first resiliency, the method comprising the steps of:

cutting out a keyswitch keyface hinge member from the sheet of material, the keyface hinge member having a base section and an intermediate section which interface at a first living hinge along the first axis, the hinge member further including a keyface section which interfaces with the intermediate section at a second living hinge along the second axis, the base section including a side still connected to a remainder of the sheet, the key face section being farthest from the connection to the remainder of the sheet, wherein the base section defines a first plane and the keyface section defines a second plane substantially parallel to said first plane when said hinge member is in a quiescent condition, said intermediate section defining a third plane traverse to said first plane and said second plane when the keyface hinge member is in said quiescent condition; and

increasing the resiliency of the first and second living hinges to a second resiliency greater than the first resiliency.

10. A method as recited in claim 9, wherein the step of increasing the resiliency includes changing a chemical makeup of the material at the first and second living hinges.

11. A method as recited in claim 10, wherein the step of changing the chemical makeup includes of one of (i) optical treatment, (ii) chemical treatment, and (iii) thermal treatment.

12. A method as recited in claim 9, wherein the step of increasing the resiliency includes making perforations in the hinge member at the first and second living hinges.

13. A method as recited in claim 12, wherein the step of making perforations is executed concurrently with the step of cutting out.

14. A method as recited in claim 12, wherein the step of making perforations includes making perforations that are evenly spaced along the first and second living hinges.

15. A method as recited in claim 12, wherein the step of making perforations includes making perforations that are circular.

16. A method as recited in claim 12, wherein the step of making perforations includes making perforations that are elongated along the first and second axes.

17. A method as recited in claim 12, wherein the step of making perforations includes making a combination of generally regular perforations and perforations elongated along the first and second axes.

18. A method as recited in claim 17, wherein:

the living hinges each have ends and a middle; and

the step of making perforations includes making generally regular perforations near the ends of the first and second axes, and making elongated perforations near the middles of the first and second axes.

19. A keyswitch assembly comprising:

electrical contact members having normally separated contacts, which make electrical contact when the keyswitch assembly is vertically compressed;

a resilient material having a cutout hinge member, the hinge member supporting a key face affixed thereon and pivotable about first and second horizontal axes intersecting the hinge member, the hinge member having a first resiliency, the hinge member including a base section and an intermediate section which interface at a first living hinge along the first axis, the hinge member further including a key section which interfaces with the intermediate section at a second living hinge along the second axis, the first and second living hinges having a second resiliency which is greater than the first resiliency, wherein the first and second living hinges have a chemical makeup, as a result of at least one (i) optical treatment, (ii) chemical treatment, and (iii) thermal treatment, which results in the second resiliency;

whereby, when the key face is pressed, the hinge member pivots about the first and second axes to make the electrical contact between the electrical contact members, and the intermediate section acts as a torsion bar to restrain the key face from twisting when pressed.

20. A method for producing a keyswitch assembly from a resilient material having a first resiliency, the method comprising:

forming a keyswitch keyface hinge member from the material, the keyface hinge member having a base section and an intermediate section which interface at a first living hinge along the first axis, the hinge member further including a keyface section which interfaces with the intermediate section at a second living hinge along the second axis, the base section including a side connected to a remainder of the sheet, the key face section being farthest from the connection to the remainder of the sheet; and

increasing the resiliency of the first and second living hinges to a second resiliency greater than the first resiliency, wherein the step of increasing the resiliency includes changing a chemical makeup of the material at the first and second living hinges.