Electricity: circuit makers and breakers – Multiple circuit control – Multiple switch
Patent
1989-02-02
1990-04-24
Burr, Edgar S.
Electricity: circuit makers and breakers
Multiple circuit control
Multiple switch
200517, 341 22, 361398, 400479, 400689, H01H 114, B41J 1904, B41J 2910
Patent
active
049202375
ABSTRACT:
A membrane keyboard has two spaced flexible membranes (1 and 2) carrying contact pad assemblies. Acoustic pads (15) of expanding ink are printed on the top surface of the upper membrane (2) between the contact pads (4) and the key buttons used to operate the contact switches formed by the pairs of opposed contact pads, thus reducing the acoustic noise and improving the contact bounce characteristic.
Optionally, printed expanding ink is also used to form the spacer (5) between the membranes (1 and 2).
REFERENCES:
patent: 3503031 (1970-03-01), Nyhus et al.
patent: 3981757 (1976-09-01), Larson
patent: 4143179 (1979-03-01), Nishikata et al.
patent: 4349712 (1982-09-01), Michalski
patent: 4439647 (1984-03-01), Calandrello et al.
patent: 4539554 (1985-09-01), Jarvis et al.
patent: 4795861 (1989-01-01), O'Rourke
"New Pressure conductive Rubber Changes Keyboard/Switch Concepts", by Amase, pp. 18-24, JEE (1/1979).
"Reduction of Bounce & Noise in a Membrane Keyboard", IBM Technical Disclosure Bulletin, vol. 28, No. 7, pp. 2773, 12/1985.
Eardley Richard A.
Keenan Brian J.
Lawson Ian A.
McAllister John
Burr Edgar S.
Cohen Moshe I.
International Business Machines - Corporation
Letson Laurence R.
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