The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 03, 1984
Filed:
May. 17, 1982
Walter L Cherry, Winnetka, IL (US);
Cherry Electrical Products Corporation, Waukegan, IL (US);
Abstract
An improved capacitive keyboard includes a plurality of switch keys that each define a minimum capacitance when in a fully extended rest state and a maximum capacitance when pressed. Each switch key has a plunger mechanism that compresses a capacitive spring when the key is pressed and releases the spring when the key is released. Each capacitive spring is affixed in operational orientation over an associated capacitive pad by soldering areas of the base coil of the spring to adjacent plated holes in a supporting printed circuit board. In operation, molten solder is applied at the underside of the printed circuit board and passes up through the plated holes by capillary action to contact the base coil of the spring. The hardened solder holds the spring in its operational position on the printed circuit board and conductively contacts the spring with an output terminal of the board.