Pushbutton tuner

Abstract

A pushbutton tuner has a plurality of pushbutton actuators each comprised of a slide plate carried by a support plate for movement between operative and inoperative positions, a lockable control plate pivotally mounted on the slide plate, and a pair of upright pins fixedly mounted on the control plate. A pair of movable plates are carried by the support plate so as to be movable across the array of slide plates and both movable plates are formed with cam edges adapted to engage one of the upright pins of the pair as the slide plate moves to its operative position. The pair of movable plates are connected at one end to first and second link members which cause the movable plates to move in opposite directions in response to the engagement of respective ones of the upright pins with respective ones of the cam edges of the movable plates. When both upright pins simultaneously engage the cam edges, the movable plates cease to move and a component of force acts on each point of engagement between the pins and the cam edges to prevent further movement of the movable plates to thereby define preset tuning frequencies. A variable tuning element has a pair of movable members connected to the first and second link members such that when one movable member ceases to move, forces acting in the same direction are applied to the pair of movable members to thereby transmit forces acting in opposite directions to the variable tuning element. Such a construction enables smooth movement of the actuators in response to a pushing force of reduced magnitude and eliminates mechanical rattling at the pivotal connection points of the parts.