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Sandwich Keyboard

IP.com Disclosure Number: IPCOM000051592D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Seibold, HK: AUTHOR

Abstract

A keyboard comprises a sensor plate 1, a spring plate 2 and a flexible cover plate 3 which are arranged on top of each other. Cover plate 3 of molded plastic has frustrum-like raised lands at the key locations. Each land is provided with a cover 4 bearing the character symbol associated with the respective key 5. At each key location, spring plate 2 has two spring tongues 6 and 7. Spring tongue 6 is formed by a U-shaped recess 9 in spring plate 2, and is bent upwards from the plane of the latter in such a manner that in the area of the hollow frustrum it rests against bottom 9 of the cover plate. Spring tongue 7 is formed by a U-shaped recess 10 in spring tongue 6.

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Sandwich Keyboard

A keyboard comprises a sensor plate 1, a spring plate 2 and a flexible cover plate 3 which are arranged on top of each other. Cover plate 3 of molded plastic has frustrum-like raised lands at the key locations. Each land is provided with a cover 4 bearing the character symbol associated with the respective key 5. At each key location, spring plate 2 has two spring tongues 6 and 7. Spring tongue 6 is formed by a U-shaped recess 9 in spring plate 2, and is bent upwards from the plane of the latter in such a manner that in the area of the hollow frustrum it rests against bottom 9 of the cover plate. Spring tongue 7 is formed by a U-shaped recess 10 in spring tongue 6. It protrudes from spring tongue 6, being convexly inclined downwards relative to sensor plate 1, without touching the latter when key 5 is in the inoperative state.

Spring tongues 6 and 7 form a spring snap system which generates a sensible and audible signal upon depression of key 5. When key 5 is depressed, spring tongue 7 touches sensor plate 1 after a particular operating stroke, causing an input pulse corresponding to the respective key to be generated in a known manner. When key 5 is depressed further, spring tongue 7 is tensioned with a sensible and audible snap effect, without spring tongue 7 and sensor plate 1 losing contact. When key 5 is depressed still further, spring tongue 6 comes to rest in a neutral area of sensor plate 1, limiting the operating stroke of the key.

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