Flexible keyboard switch with integral spacer protrusions

• US 4,145,584 A
• Filed: 04/25/1977
• Issued: 03/20/1979
• Est. Priority Date: 04/28/1976
• Status: Expired due to Term

• Current Assignee: Jon L. Otterlei
• Original Assignee: Jon L. Otterlei
• Inventors: Otterlei, Jon L.
• Primary Examiner(s): Scott, James R.
• Application Number:
  US05/790,759
• Time in Patent Office: 694 Days
• Field of Search: 200/1 R, 200/5 R, 200/5 A, 200/16 A, 200/86 R, 200/159 R, 200/159 A, 200/159 B, 200/292, 200/83 L, 361/398, 174/68.5, 200/83 L
• 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 13/703 characterised by spacers between contact carrying layers
• CPC Class Codes: H01H 2203/02 Interspersed fingers
• CPC Class Codes: H01H 2203/054 for redundancy, e.g. several contact pairs in parallel
• CPC Class Codes: H01H 2207/004 Printed circuit tail
• CPC Class Codes: H01H 2207/022 Plug
• CPC Class Codes: H01H 2209/014 composed of different layers; Lubricant in between
• CPC Class Codes: H01H 2209/032 non elastomeric
• CPC Class Codes: H01H 2209/07 metallic
• CPC Class Codes: H01H 2211/03 Ridges on layers
• CPC Class Codes: H01H 2219/028 Printed information
• CPC Class Codes: H01H 2219/034 Coloured areas
• CPC Class Codes: H01H 2219/036 Light emitting elements
• CPC Class Codes: H01H 2223/024 Screw
• CPC Class Codes: H01H 2223/034 Bezel
• CPC Class Codes: H01H 2227/002 Layer thickness
• CPC Class Codes: H01H 2227/024 Spacer elements
• CPC Class Codes: H01H 2229/028 Adhesive
• CPC Class Codes: H01H 2229/038 Folding of flexible printed circuit
• CPC Class Codes: H01H 2229/05 Forming; Half-punching
• CPC Class Codes: H01H 2229/062 : Maintenance or repair facilities
• CPC Class Codes: H01H 2231/012 : Household appliance
• CPC Class Codes: H01H 2239/01 : combined with other elements on the same substrate

Abstract

A keyboard switch construction in which contacting surfaces in spaced apposition on resilient, flexible, electrically non-conductive laminae are prevented from making contact in the absence of outside pressure by ribs formed in the material and substantially surrounding the conducting surface on one lamina. The switch construction is used in a control panel arrangement in which pilot and operative components are separately mounted and are associated by printed circuitry carried on a flexible insulating strip which may be physically continuous or may be electrically continuous using a multi-contact connector to interconnect two physically separate halves of the sheet.

Claims

1. In combination:

a pair of smooth sheets of flexible, resilient, electrically insulating material having first surfaces in apposition, said sheets being of uniform thickness;

a first area of electrically conductive material on said first surface of one of said sheets;

a second area of electrically conductive material on the first surface of the other sheet in apposition with said first area;

means independently making electrical connection with said areas;

and a raised ridge embossed in one of said sheets substantially surrounding one of said areas closely enough to normally prevent contact between said areas in the absence of pressure applied externally to the sheets within the outline of said areas, the height of said ridge being of the same order of magnitude as the thickness of the sheet.

2. A keyboard switch construction comprising, in combination:

a sheet of foldable, resilient, electrically insulating material having a fold line, said sheet being of uniform thickness;

a first area of electrically conductive material on one face of said sheet and on one side of said fold line;

a second area of electrically conductive material on the same face of said sheet on the opposite side of said fold line, so that when said sheet is folded on said line, said areas are in apposition;

means independently making permanent electrical connection with said areas;

and a raised ridge embossed in said sheet substantially surrounding one of said areas closely enough to normally prevent contact between said areas in the absence of pressure applied externally to said sheet within the outline of said areas, the height of said ridge being of the same order of magnitude as the thickness of said sheet.

3. A keyboard switch construction, comprising, in combination:

a smooth sheet of foldable, resilient, electrically insulating material of uniform thickness having a fold line;

a first area of electrically conductive material on one face of said sheet and on one side of said fold line;

an elongated conductor on the same face of said sheet on the opposite side of said fold line, so that when said sheet is folded said area and said conductor are in apposition;

and at least one elongated raised ridge embossed in said sheet and along and adjacent to said conductor and close enough thereto to normally prevent electrical contact thereof with said area, the height of said ridge being of the same order of magnitude as the thickness of said sheet.

4. In combination:

a pair of sheets of flexible, resilient, electrically insulating material of uniform thickness having first surfaces in apposition;

electrically conductive means carried by at least one area of said first surface of one of said sheets;

further electrically conducting means carried by at least one area of the first surface of the other sheet in apposition to the first named electrically conducting means;

independent conductor means making permanent electrical connection to the electrically conductive means of at least one area so that when said areas are brought into engagement an electrical circuit is completed between said conductive means;

and a raised ridge embossed in at least one of said sheets adjacent at least one of said areas and close enough thereto to normally prevent engagement between said areas in the absence of pressure applied externally to the sheets within the outline of said areas, the height of said ridge being of the same order of magnitude as the thickness of the sheet.

5. The method of preventing unintended contact between electrically conductive areas on apposed surfaces of resilient non-conductive sheet material of uniform thickness which comprises bordering one of the areas with a ridge embossed in the material to substantially and closely surround the conductive area thereon, the height of said ridge being of the same order of magnitude as the thickness of said sheet.

6. A composite structure comprising, in combination:

a first, flexible sheet of insulating material of uniform thickness;

a second, smaller, rigid sheet of insulating material having one face secured to a first portion of one face of said first sheet;

a plurality of discrete electrical components mounted by their conductors on the other face of said second sheet with the conductors passing through apertures in both said sheets;

a printed circuit on the other face of said first sheet interconnecting said components and extending beyond said second sheet to form the fixed contacts of a bank of normally open switches;

a stiffener sheet smaller than said first sheet and secured to a second portion of said one face of said first sheet opposite said fixed contacts;

means mounting said sheets with said second sheet parallel to and spaced from said stiffener sheet, said components being contained between said second sheet and said stiffener sheet, and said first sheet being folded so that said fixed contacts are on the outside of the space containing said components;

flexible electrically conductive means mounted in alignment with said contacts of said bank of switches for actuation into engagement therewith selectively to close said switches;

means normally preventing engagement between said fixed contacts and said flexible conductive means;

and means for applying localized pressure to said flexible electrically-conductive means to enforce engagement thereof with selected fixed contacts of said bank of switches.

7. A composite structure comprising, in combination:

a rigid mounting sheet of insulating material;

a stiffener sheet;

means mounting said sheets in aligned spaced relationship with inner faces thereof in apposition;

a folded sheet of flexible insulating material having an inner face secured to the outer faces of said mounting sheet and said stiffener sheet;

a plurality of discrete electrical components mounted by their conductors on the inner face of said mounting sheet with the conductors passing through apertures in said mounting sheet and said folded sheet;

a printed circuit on the outer face of said folded sheet interconnecting said components and extending beyond said mounting sheet to comprise the fixed contacts of a bank of normally open switches supported by said stiffener sheet;

flexible electrically conductive means aligned with said contacts of said bank of switches for actuation into engagement therewith to close said switches;

means normally preventing engagement between said fixed contacts and said flexible conductive means;

and means for applying localized pressure to said flexible electrically-conductive means to enforce engagement thereof with selected fixed contacts of said bank of switches.

8. A structure according to claim 7 in which said folded sheet is discontinuous at the fold and a multiple-contact electrical connector enables separation and reconnection between the portions thereof at said discontinuity.

9. A control structure comprising, in combination:

a rigid mounting sheet of insulating material;

a stiffener sheet;

means mounting said sheets in aligned spaced relationship with inner faces thereof in apposition;

a folded sheet of flexible insulating material having an inner face apposed to the outer faces of said mounting sheet and said stiffener sheet, and secured to the outer face of said mounting sheet;

a plurality of discrete electrical components mounted by their conductors on the inner face of said mounting sheet with the conductors passing through apertures in said mounting sheet and said folded sheet

a first printed circuit, on the outer face of said folded sheet in apposition with said mounting sheet, interconnecting said components;

a second printed circuit, on said folded sheet in apposition with said stiffening sheet, interconnected with said first printed circuit and comprising the fixed contacts of a bank of normally open switches;

flexible electrically conductive means between said stiffener sheet and said second printed circuit and aligned with said contacts of said bank of switches for engagement therewith to close said switches;

means normally preventing engagement between said fixed contacts and said flexible conductive means;

and means for applying localized pressure to said folded sheet against said stiffener sheet to enable engagement of selected switch contacts with said flexible conductive means so as to close selected switches.

10. A structure according to claim 9 in which said first and second printed circuits are on opposite faces of said folded sheet.

11. In combination:

a first smooth sheet of flexible, resilient, electrically insulating material of uniform thickness;

a contact area of electrically conductive material at a predetermined location on said first sheet;

a raised ridge embossed in said insulating material substantially surrounding and close to said contact area, the height of said ridge being of the same order of magnitude as the thickness of the sheet;

a second sheet of flexible, resilient, electrically conductive material, mounted in engagement with said ridge of said first sheet to be prevented thereby from physical engagement with said contact area in the absence of enabling force applied in a direction normal to said sheets at the location of said contact area;

and support means preventing overall movement of both said sheets in said direction upon application of said enabling force.

12. A composite structure comprising,

an electrical connector having plural contacts in spaced side by side relationship;

a circuit board having a plurality of discrete electrical components mounted thereon including said connector, and having a first printed circuit interconnecting said components;

a sheet of insulating material having a second printed circuit comprising the fixed contacts of at least one normally open switch and conductors leading therefrom to the edge of said sheet in the same spaced relation as that of contacts of said connector, so that when said sheet is inserted into said connector circuits are completed from said switch contacts to said first printed circuit, said sheet being flexible to enable it to fold over said circuit board in spaced relation therefrom;

a ridge of insulating material substantially surrounding said fixed contacts of each said switch;

a support board between said circuit board and the folded sheet;

and means mounting an electrically conducting surface in line with said fixed contacts and spaced therefrom by said ridge, so that an electrical circuit is completed thereby in response to pressure applied therethrough against said support board.

13. A printed circuit switch comprising, in combination:

a smooth sheet of electrically insulating material of uniform thickness;

a pair of fixed switch contacts, in close, mutually spaced relation, carried by said sheet;

laminar electrical conducting means apposed to said contacts;

means for enabling relative movement between said sheet and said conducting means to enable simultaneous engagement of said conducting means with said fixed contacts, for completing a circuit therebetween and thereby performing a switching function;

said fixed contacts having configurations of conjoint area;

and said sheet including an embossed ridge of electricaly insulating material substantially surrounding said conjoint area closely enough to prevent engagement of said contacts by said conducting means in the absence of applied enabling force at said conjoint area, the height of said ridge being of the same order of magnitude as the thickness of said sheet.

14. A printed circuit switch comprising, in combination:

a smooth sheet of electrically insulating material of uniform thickness;

pairs of fixed switch contacts carried by said sheet, the contacts of each pair being in close, mutually spaced relation;

laminar electrical conducting means apposed to said contacts;

means for enabling relative movement between said sheet and said conducting means to enable simultaneous engagement of said conducting means with the fixed contacts of any of said pairs, for completing a circuit therebetween, and thereby performing a switching function;

the fixed contacts of each pair having comb-like configurations of known conjoint area,

and said sheet including embossed ridges of electrically insulating material substantially surrounding said conjoint areas closely enough to prevent engagement of said contacts by said conducting means in the absence of applied enabling force at one of said conjoint areas, the height of said ridge being of the same order of magnitude as the thickness of said sheet.

15. An article of manufacture comprising, in combination:

a sheet of rigid, electrically insulating material having a field of spaced perforations passing therethrough;

a smooth sheet of flexible, resilient, electrically insulating material of uniform thickness, said sheet being larger than the first named sheet, and having a portion perforated in agreement with the perforations in said first named sheet;

means securing a first surface of the first named sheet to a first surface of said portion of the second named sheet with the perforations in alignment;

electrically conductive material carried on the second surface of the second named sheet, to define a plurality of conductive paths extending from the sites of said perforations and a plurality of conductive areas comprising the fixed contacts of a plurality of normally opened switches at a second portion of said second named sheet;

a plurality of discrete electrical components positioned on the second surface of the first named sheet, and having conductors extending through said perforations to terminate at sites in said conductive paths;

means connecting said conductors to said conductive material at said perforations to mount said components on said first named sheet and complete electrical circuits to said components;

further electrical conducting means movably operable to comprise the movable contacts of said switches; and

means normally preventing engagement between said fixed and movable contacts, in the absence of force applied therebetween, comprising embossed ridges in said second named sheet substantially surrounding said conductive areas.