Keyboard with metal cover and improved switches

• US 4,771,139 A
• Filed: 06/27/1986
• Issued: 09/13/1988
• Est. Priority Date: 06/27/1986
• Status: Expired due to Fees

• Current Assignee: EXPO Telektron Safety System Limited
• Original Assignee: Gregory L. Desmet
• Inventors: DeSmet, Gregory L.
• Primary Examiner(s): Scott, J. R.
• Application Number:
  US06/879,284
• Time in Patent Office: 809 Days
• Field of Search: 200/5 A, 200/83 B, 200/86 R, 200/159 B, 200/160, 200/302.1, 200/302.2, 200/308, 200/310, 200/314, 200/317, 200/329, 200/340
• US Class Current: 200/5.00A
• CPC Class Codes: H01H 13/7006 comprising a separate movable contact element for each switch site, all other elements being integrated in layers
• CPC Class Codes: H01H 13/807 characterised by the spatial arrangement of the contact sites, e.g. superimposed sites
• CPC Class Codes: H01H 2207/022 Plug
• CPC Class Codes: H01H 2209/07 metallic
• CPC Class Codes: H01H 2219/028 Printed information
• CPC Class Codes: H01H 2221/002 integral with membrane
• CPC Class Codes: H01H 2223/002 sealed
• CPC Class Codes: H01H 2225/002 superimposed
• CPC Class Codes: H01H 2225/014 normally closed combined with normally open
• CPC Class Codes: H01H 2229/016 Selective etching
• CPC Class Codes: H01H 2237/006 Guided plunger or ball
• CPC Class Codes: H01H 2239/004 High frequency adaptation or shielding
• CPC Class Codes: H01H 2239/034 Environmental protection
• CPC Class Codes: H01H 2239/072 High temperature considerations
• CPC Class Codes: H01H 9/042 Explosion-proof cases

Abstract

An improved keyboard is provided with a flexible metal cover, normally closed switches, and multiple throw switches. The metal cover is made flexible in the area of each key or switch by the provision of grooves in the metal surrounding each flexible portion. The normally closed and multiple throw switches include pellets which transmit the actuating force on a key or switch through a substrate on which a switch is mounted. The device may be configured in such a way that the pellet will push the normally closed contacts of a switch out of contact, or the pellet or pellets may mechanically link a stacked set of switches in order to provided ganged, multiple throw operation.

Claims

1. A keyboard comprising

a layer of metal etched with a plurality of closed-loop grooves, at least one pair of said grooves defining a keysite region wherein said region is made flexible by a bellows effect;

and

an insulating layer disposed between said keysite region and a switch contact;

wherein said keysite region is thinner than said layer of metal.

2. The invention of claim 1 wherein said grooves are disposed on alternate sides of the sheet.

3. The invention of claim 1 wherein the depths of said grooves are approximately one-half thickness of said layer of metal.

4. The device of claim 1 wherein at least a portion of said layer of metal is affixed to a base, said portion and said base thereby defining a sealed compartment.

5. The device of claim 1 wherein the laterally adjacent edges of a first and a second of said plurality of grooves are separated by less than approximately twice the thickness of said layer of metal.

6. A keyboard as claimed in claim 1, wherein said grooves are substantially shallower than the thickness of said layer of metal.

7. A keyboard as claimed in claim 1, wherein said layer of metal is substantially fluid-tight.

8. A keyboard as claimed in claim 1, wherein said key site region is substantially planar with a region of said layer of metal local to said key site region.

9. A keyboard comprising

a metal sheet having at least one region defined by an area of reduced thickness and a groove surrounding said area, wherein said region is made flexible by a bellows effect;

and

an insulating layer disposed between said region and a switch contact;

wherein said region is thinner than said metal sheet.

10. The invention of claim 9 wherein said groove is on the opposite side of said sheet from said area of reduced thickness.

11. The invention of claim 9 wherein the depths of said groove and of said area of reduced thickness are approximately one-half the thickness of said metal sheet.

12. A keyboard comprising a layer of metal etched with a plurality of closed-loop grooves, at least one pair of said grooves defining a keysite region wherein said region is made flexible by a bellows effect, comprising

first and second contact electrodes,

a substrate having an opening therethrough,

a resilient electrically conductive member in contact with said first contact electrode and held in contact with said second contact electrode by a spring force, such that an electrical circuit is completed between said first and second electrodes and the electrically conductive member, and

a pellet positioned in said opening in said substrate,

whereby movement of an actuating cover toward the substrate will be transmitted by the pellet through said opening in said substrate to the resilient electrically conductive member, urging it out of contact from said second contact electrode and thereby breaking the electrical circuit.

13. The invention of claim 12, further comprising

a second pellet operatively connected to said first pellet disposed in line with said first pellet and said actuating cover;

a second resilient member operatively connected to said second pellet disposed in line with said second pellet and said actuating cover, whereby a spring force generated by said second resilient member causes said actuating cover to be urged outwardly from said substrate.

14. The invention of claim 13, wherein said second resilient member is a dome spring having an edge resting on a second substrate.

15. The invention of claim 12 wherein said keyboard includes a region with a pushbutton shape.

16. Apparatus comprising a plurality of switches arranged on an axis, each switch comprising first and second contact electrodes mounted on a flat substrate, and a resilient electrically conductive member for completing an electrical circuit between said first and second contact electrodes in a first position along said axis, and for opening said electrical circuit in a second position along said axis;

said first position and said second position being independently defined for each switch;

a pellet disposed between and resting against each resilient electrically conductive member and the resilient electrically conductive member immediately axially adjacent thereto; and

each said substrate defining a hole through which said pellet may move, transmitting mechanical movement of an actuating cover to each electrically conductive resilient member.

17. The device of claim 16 wherein at least one of said pellets is of a generally compliant material.

18. The device of claim 16 wherein said substrates comprise circuit board material pre-impregnated with epoxy adhesive.

19. The device of claim 16 wherein at least one of said plurality of switches comprises a normally closed switch in which said resilient electrically conductive member rests in contact with said first and second contact electrodes, said pellet resting against said resilient electrically conductive member whereby mechanical movement of said actuating cover is transmitted to said member thus interrupting said electrical circuit.

20. A metal keyboard cover having at least one key site defined by and made flexible by the provision of substantially laterally adjacent grooves and having an insert capable of transmitting light being bonded to said cover over said opening;

an insulating layer disposed between said key site and a switch contact;

wherein said key site is thinner than said metal keyboard cover.

21. A keyboard comprising

a hermetic layer of substantially non-resilient material;

at least one region in said layer defined by a plurality of closed-loop grooves, said region being made flexible by a bellows effect;

an insulating layer disposed between said region and a switch contact;

wherein said keysite region is thinner than said layer.