Japanese Patent JPS557643

B2

1430399 Retractive switches BOWMAR INSTRUMENT CORP 20 Dec 1973 [2 Jan 1973] 59172/73 Heading H1N A keyboard switch assembly comprises pushbuttons 22 each of which actuates a resilient, conductive switch device 14 from a rest position to a deflected position in which it interconnects co-planar conductors such as 30-3, 32, Fig. 5, carried by, for example by being printed on, an insulating board 12, at least one other conductor being provided on the board spaced from and co-planar with the first-mentioned conductors and extending under the switch device but having no electrical connection therewith in either of its positions. As shown, the switch device is a snap-acting dome of, for example, square, triangular or circular shape and formed with dimples or projections 64, 66 on its periphery and at the centre thereof respectively, which form contact portions for engaging the conductors. The switching devices are located in apertures 74 in an insulating sheet 16 superimposed on the board 12 and over which is laid a flexible insulating cover sheet 18. The assembly is completed by a cover member 20 which is apertured at 76 for retention and location of the push-buttons. The latter have X-shaped projections 78 which act through the sheet 18 on the switching devices. The conductors and parts thereof which are not engaged by a particular switching device may be covered with an insulating layer (56), Fig. 7 (not shown), and the contact portions of the conductors may be plated with gold on nickel. Fig. 11 shows a modification in which an insulating sheet 82 extends between the sheet 16 and board 12 and has apertures such as 86, 88 which expose the contact portions of the conductors for engagement by the dimples 641, 66 of the switching device 141.

JP14461773A

February 27, 1980

December 27, 1973

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G06F3/02; H01H13/48; H01H5/30; H01H13/52; H01H13/70; H01H13/785

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