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Stabilized molded rubber keyboards

  • US 4,764,770 A
  • Filed: 06/11/1986
  • Issued: 08/16/1988
  • Est. Priority Date: 06/11/1986
  • Status: Expired due to Term
First Claim
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1. In a keyboard assembly having a PC board providing a series of switches and a molded rubber keyboard providing a rubber base sheet overlying said PC board and having a series of rubber keys integral with said base sheet, each said key having contact means on its bottom surface for closing each said switch when its key is depressed, said keyboard having sufficient inherent elasticity to restore any depressed key back to its original position when the key is released, the combination therewith ofstabilizing membrane means for preventing said keys from wobbling or binding, said membrane means having a first surface disposed on an opposite side of said rubber base sheet from said PC board and a second surface separated from said first surface by the height of said membrane means, said keys extending through said membrane means such that each said key extends from beneath said first surface to above said second surface so that each said key can be depressed by direct contact by a finger of a user, said membrane means being substantially continuous around the periphery of each said key for snugly engaging each said key around substantially its entire periphery, said membrane means being flexible along its Z axis, but sufficiently still along its X and Y axes, to remain in contact with substantially the entire periphery of each said key and to limit the movement of said keys to a strictly linear movement toward and away from their respective PC board switches, the flexibility of said membrane means along its Z axis enabling said membrane means to follow each said key up and down without binding it.

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