Browse Prior Art Database

Keyboard with Pretravel Force

IP.com Disclosure Number: IPCOM000052925D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Perkins, NK: AUTHOR

Abstract

A buckling spring-type keyboard utilizes a spring having a larger diameter in one section than in another to provide two levels of force as the keybutton is depressed.

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Keyboard with Pretravel Force

A buckling spring-type keyboard utilizes a spring having a larger diameter in one section than in another to provide two levels of force as the keybutton is depressed.

Keybutton 11 is depressed by an operator, causing it to move downward relative to housing 13. Buckling spring 15 has a larger diameter at 17 than at 19. Thus, the spring collapses at 17 first at approximately 20 grams of pressure. As the keybutton 11 continues down, the smaller section at 19 starts collapsing and encircling the conical stud 21 on pivot plate 23. This section of the spring provides a greater resistance force in the neighborhood of 4O to 6O grams. At a predetermined point in the downward stroke, the body of the spring 15 buckles, causing the pivot plate 23 to pivot on heel 25 so as to contact the pad card 27. This contact is capacitively sensed to indicate keybutton actuation.

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