Abstract: A transmission mechanism includes an outer sleeve and an eccentric wheel. The outer sleeve is fixed to a movable block. The eccentric wheel is rotatably installed in the outer sleeve. The eccentric wheel is rotatable relative to the outer sleeve. The eccentric wheel has a mounting hole mountable on a drive shaft. A central axis of the mounting hole is parallel to, and at a predetermined distance from, a central axis of the eccentric wheel, such that the transmission mechanism can convert a rotational motion of the drive shaft into a linear reciprocating motion of the movable block.

Abstract: A pushbutton switch for use in a keyboard attached to a computer system, word processor, electric typewriter, etc., is implemented to give the operator both a tactile feel and a click sound when a key is entirely depressed. The switch comprises a housing, an actuating arm, a stem and a leaf spring mechanism. The leaf spring has an upright portion with a hook, a bent portion, a spring portion and a protruding portion. It is mounted in the housing such that when the stem is partially depressed, it forces the upright portion to slant toward the inner surface of side wall of the housing and the spring portion to be compressed. When the spring is depressed beyond a certain position, the protruding portion of the leaf spring slips off the ledge of the step portion of the side wall of the housing, causing the bent portion to snap toward and collide with the outer surface of the stem, thus producing the desired click sound.

Abstract: A keyboard switch for use with a membrane switch array (20) to provide a tactile feeling and, optionally, a click sound comprises a housing (10) which is positioned on the membrane switch array (20). A plunger (13) is reciprocally mounted within the housing (10) and projects outwardly from the housing, the plunger having a cam portion (133). An actuating arm (14) is pivoted to the housing (10) and has a first portion (141) extending beneath the plunger (13) and a second, cam follower portion (142) which engages the cam portion (133) of the plunger (13). The first portion (141) of the actuating arm (14) has a boss (1412) on its surface facing away from the plunger (13) for engaging the switch array (20). A compression spring (15) extends between the plunger (13) and the first portion 141 of the actuating arm (14) to urge the plunger (13) outwardly from the housing (10 ).