Browse Prior Art Database

Pivot Plate Actuator With Improved Force Loading

IP.com Disclosure Number: IPCOM000048822D
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Bellamy, RL: AUTHOR [+4]

Abstract

In order to insure intimate contact between a pivot plate and its co-acting circuit board in a capacitive switch arrangement as described in U.S. Patent 4,118,611, either an extension of the pivot plate or an extension of the buckling spring is caused to act between the side of the buckling spring and the top surface of the pivot plate as the spring is buckled, thereby providing an additional force point on the pivot plate.

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Pivot Plate Actuator With Improved Force Loading

In order to insure intimate contact between a pivot plate and its co-acting circuit board in a capacitive switch arrangement as described in U.S. Patent 4,118,611, either an extension of the pivot plate or an extension of the buckling spring is caused to act between the side of the buckling spring and the top surface of the pivot plate as the spring is buckled, thereby providing an additional force point on the pivot plate.

A capacitive switch arrangement such as described in U.S. Patent 4,118,611 is depicted in Figs. 1 and 2. Downward motion of a keybutton (not shown) attached to spring 11 causes the spring to buckle from its position shown in Fig.
1. The bottom of spring 11 is connected to pivot plate 13, and the buckling action of the spring applies a torsional moment to pivot plate 13, causing it to rock downwardly onto circuit board 15, changing the value of sensed capacitance on circuit board 15. As spring 11 starts to buckle, its side contacts extension 17 of the spring 11 in Fig. 1 or, alternatively, an extension 19 of pivot plate 13 in Fig. 2, transmitting a direct force to pivot plate 13 at point 21, thereby increasing the force as measured at location 23. This increased force reduces the bounce of pivot plate 13 as it strikes the surface of board 15. The direct force at point 21 occurs on the right side of pivot point 25 and complements the normal axial force applied to the spring post (not shown) of piv...