Browse Prior Art Database

Coded Overlay Sensing Mechanism

IP.com Disclosure Number: IPCOM000043739D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Keplar, KW: AUTHOR

Abstract

Various keyboards exist of membrane, mechanical or capacitive, electronic or magnetic technology in which changeable indicia overlay sheets are employed with coded elements on their edge to identify to a using system which overlay is in place to modify the interpretation given to the key strokes when they are decoded. In fast food and other similar industries, a contamination shield or permanent membrane must be in place over the key elements to avoid fouling due to spilled foodstuffs and the like. This disclosure provides a coded overlay indicia sheet with encoding tabs on its edge that actuate mechanical switches beneath the permanent contamination shield on such a keyboard to indicate to a using system which overlay is in place.

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Coded Overlay Sensing Mechanism

Various keyboards exist of membrane, mechanical or capacitive, electronic or magnetic technology in which changeable indicia overlay sheets are employed with coded elements on their edge to identify to a using system which overlay is in place to modify the interpretation given to the key strokes when they are decoded. In fast food and other similar industries, a contamination shield or permanent membrane must be in place over the key elements to avoid fouling due to spilled foodstuffs and the like. This disclosure provides a coded overlay indicia sheet with encoding tabs on its edge that actuate mechanical switches beneath the permanent contamination shield on such a keyboard to indicate to a using system which overlay is in place. In the figure, a keyboard assembly 1 has a number of key switches or sensing switches 2 which are provided with output leads or conductors 3. The framework 4 separates the areas of the keyboard 1 into compartments or acts as a divider between the various key switches 2. Located along one edge, which is shown in cross section in the figure, a number of the overlay sensing switches 2 having actuator tops 9 are placed beneath a spring pressure element 5. A permanent protective contamination shield of flexible plastic or rubber material is shown as element 3 overlying the tops of the actuators 9 and shielding the switches 2 from any contamination from above. A protective edge cover 6 shields the spring element 5 along the edge of the keyboard 1 but liquids or foodstuffs might still enter in the opening between the contamination shield 3 and the cover 6. This opening must be present to allow the removable indicia overlay sheet 7 to be inserted. Individual tabs, shown as 8, along the edge of the re...