Car radio tuning device with push-button station selector - with coupling device actuated after pre-locking to prevent de-tuning

摘要

An S-shaped clamping lever is provided with an engagement contour near one extremity that first applies a light preclamping pressure allowing a semicircular half disc to accommodate its position to that of the tuning element set by a tuning knob, as a station selector push-button is first moved from its extreme withdrawn position inwardly. Until this pre-clamping operation is completed, the tuning knob remains coupled to the tuning element of the radio receiver. As the push-button is further actuated inwards, an offset arm on a strip-shaped member operates a coupling device to release the coupling between the tuning knob and the tuning element. The clamping lever than progressively provides more force until it reaches a stable position where the half disc is locked to the tuning slide. The bearing element against which the contour of the clamping lever works is a roller bridging a slot in the inner end of the strip-shaped member, and the friction of the engagement is low enough so that if the stable locked position is not reached, a push-button will be restored to its withdrawn position by a leaf spring acting on the clamping lever.