Touch switch and contactor therefor

• US 4,243,861 A
• Filed: 11/20/1978
• Issued: 01/06/1981
• Est. Priority Date: 06/24/1977
• Status: Expired due to Term

• Current Assignee: Cornelius Co. (Minnesota) (IMI PLC)
• Original Assignee: Cornelius Co. (Minnesota) (IMI PLC)
• Inventors: Strandwitz, Peter
• Primary Examiner(s): Marcus, Stephen
• Application Number:
  US05/962,540
• Time in Patent Office: 778 Days
• Field of Search: 200/5 A, 200/86 R, 200/159 B, 200/262, 200/267, 200/292, 200/340, 340/365 R, 340/365 A, 340/365 E, 428/255
• US Class Current: 200/512
• 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 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/026 non precious
• CPC Class Codes: H01H 2201/03 Composite
• CPC Class Codes: H01H 2203/02 Interspersed fingers
• CPC Class Codes: H01H 2203/032 Metal foil
• CPC Class Codes: H01H 2203/054 for redundancy, e.g. several contact pairs in parallel
• CPC Class Codes: H01H 2209/002 Materials
• CPC Class Codes: H01H 2209/01 Increasing rigidity; Anti-creep
• CPC Class Codes: H01H 2209/048 metallic
• CPC Class Codes: H01H 2227/002 Layer thickness
• CPC Class Codes: H01H 2227/018 Printed contacts; Metal foil
• CPC Class Codes: H01H 2229/028 Adhesive
• CPC Class Codes: H01H 2239/034 Environmental protection
• CPC Class Codes: H01H 2239/038 Anti-vandalism

Abstract

An electrical touch switch having a printed circuit baseboard with two circuit patterns electrically isolated and spaced a predetermined distance from one another has a contactor having a resiliently flexible substrate with a plurality of small contactor dots positioned randomly with respect to the circuit patterns, each contactor dot is sufficiently large to span across the spacing between the circuit patterns and depression of any one of these dots against the circuit patterns will provide continuity between the circuit patterns; the contactor substrate also has embedded structural fibers which span across the contactor dots.

Claims

1. An electrical touch switch, comprising:

(a) an electrically non-conductive base board;

(b) an electrically conductive contact grid upon said board, said grid having

(1) a first circuit pattern having means for electrical connection to a first electrical lead, and

(2) a second circuit pattern electrically isolated and spaced a predetermined distance from said first pattern, and having means for electrical connection to a second electrical lead;

(c) means for securing a contactor sheet to said base board and atop of said grid;

(d) a contactor sheet secured to said board by said securing means, said contactor sheet having an inner surface facing towards, exposed to and spaced from said grid, and being resiliently flexible with respect to said board such that a portion of the contactor sheet facing directly against the grid may be manually depressed for biasing said sheet inner surface toward said grid; and

(e) a plurality of discrete electrically isolated and electrically conductive contactor dots on the inner surface of said contactor sheet and facing directly against said first and second circuit patterns and being normally spaced from said patterns, said contactor dots each having a major distance thereacross which is greater than said predetermined distance between said first and second circuit patterns for providing electrical continuity between said patterns upon physical contact of any one of said contactor dots against said patterns, with every pair of adjacent contactor dots being identically equidistant from each other, and in which a minor distance across each contactor dot is greater than the combined distance of the spacing between said first and second circuit patterns and the width of a contact element of either circuit pattern.

2. A touch switch according to claim 1, in which the minor distance across each contactor dot is at least equal to the combined width of a pair of adjacent elements of said contact grid, and one and one-half times the predetermined distance between said adjacent contact elements.

3. An electrical touch switch, comprising:

(a) an electrically non-conductive baseboard;

(b) an electrically conductive contact grid upon said board, said grid having

(1) a first circuit pattern having means for electrical connection to a first electrical lead, and

(2) a second circuit pattern electrically isolated and spaced continuously equidistant from said first pattern, and having means for electrical connection to a second electrical lead;

(c) means for securing a contactor sheet to said baseboard and atop of said grid;

(d) a contactor sheet secured to said board by said securing means, said contactor sheet having an inner surface facing towards, exposed to and spaced from said grid and being resiliently flexible with respect to said board such that a portion of contactor sheet facing directly against the grid may be manually depressed for biasing said sheet inner surface toward said grid;

(e) a plurality of discrete electrically isolated and electrically conductive contactor dots on the inner surface of said contactor sheet and facing directly against said first and second circuit patterns and being normally spaced from said patterns, said contactor dots being identical to one another with each having a major distance thereacross which is greater than said predetermined distance between said first and second circuit patterns for providing electrical continuity between said patterns upon physical contact of anyone of said contactor dots against said patterns, and in which

(f) said contactor dots are a uniformly repetitive pattern randomly positioned on said contactor sheet and with respect to said contact grid.

4. An electrical touch switch according to claim 3, in which said contactor has been randomly cut from a bulk sheet of contactor material.

5. An electrical touch switch, comprising:

(a) an electrically non-conductive baseboard;

(b) an electrically conductive contact grid upon said board, said grid having

(1) a first circuit pattern having means for electrical connection to a first electrical lead, and

(2) a second circuit pattern electrically isolated and spaced a predetermined distance from said first pattern, and having means for electrical connection to a second electrical lead;

(c) a contactor sheet secured to said board and having an inner surface facing towards, exposed to and spaced from said grid, said contactor sheet being resiliently flexible with respect to said board such that a portion of the contactor sheet facing directly against the grid may be manually depressed for biasing said contactor sheet toward said grid;

(d) a plurality of discrete electrically isolated and electrically conductive metal foil contactor dots in a continuous repetitive pattern on the inner surface of said contactor sheet, some of said dots facing directly against said first and second circuit patterns and being normally spaced from said patterns, said contactor dots each having a major distance thereacross which is greater than said predetermined distance between said first and second circuit patterns for providing electrical continuity between said patterns upon physical contact of one of said contactor dots against said patterns;

(e) a metal margin on said baseboard, said metal margin being on opposite sides of and on the same side of the baseboard as said contact grid and being electrically isolated from said grid and spaced from said grid a distance greater than the major distance across any discrete contactor dot; and

in which

(f) some of said contactor dots are secured to said baseboard metal margin, said contactor sheet being secured to said board via such secured contactor dots.