GB602457A - Improvements in or relating to radio tuning apparatus - Google Patents

Abstract

602,457. Push-button tuning mechanism. CRAMER, S. S. Oct. 24, 1944, No. 20615. Convention date, Dec. 30, 1943. [Class 40 (i)] A preset tuning device has means for moving a tuning member, first to one extreme position and then towards the other, means being provided to stop the member on the return, when it reaches a predetermined position. Figs. 1, 5 and 8 show'one arrangement, in which energization of an electromagnet 10 (Fig. 8), oonnected in series with electromagnet 46 and a selected one of the group of electromagnets 41 causes an armature 8 connected to the capacitor rotor to -rotate against spring 13 (Fig. 1). On reaching the " all out " position, the rotor plates depress an arm 53 (Fig. 8), cutting out electromagnet 10, so that the armature is rotated by the spring in the opposite direction. A locking device, including electromagnet 46 is provided to prevent the return of member 53 until the circuit is de-energized. The energization of one of electromagnets 41 causes an associated pivotally mounted member 32 (Fig. 5) to be pulled into the path of a pin mounted on shaft 19 which is connected through gearing to the capacitor rotor, so that the rotor is stopped in a position dependent on the setting of member 32, which is determined by a setting screw 28. In a modification (Fig. 9, not shown), a member carried by the armature cuts out the driving electromagnet 10 by striking a contact actuating member, which also locks itself in position by causing a current to flow through a winding of which it forms the core. The set may be muted during tuning by grounding the aerial, shorting the speaker, or cutting off the receiver supply. Indication that tuning has been effected may be given by lighting lamps mounted behind translucent push-buttons. Specification 600,717, [Group XXXV], is referred to.