GB603775A - Improvements in tuning apparatus for radio receivers or the like - Google Patents

Abstract

603,775. Adjusting radio apparatus. COLE, Ltd., E. K., and KNIPE, A. R. April 29, 1939, No. 12840. [Class 40 (v)] In a two-speed drive for a radio tuning unit, a cord is wound upon or unwound from two pulleys of different diameters over a planet roller which moves into the path of a stop to give a direct drive between the knob and the variable tuning element. As shown, the shaft S of a variable condenser is connected through a pointer support L and a link J to a sleeve M, rotatable about the shaft, carrying a driven pulley R1. A driving pulley R2, of smaller diameter than R1, rotatable about the sleeve M, is held against the condenser mounting by a friction disc E and spring F. A cord U, anchored by a spring to the pulley R1, passes round this pulley, over a planet roller C, on to the pulley R2, round another planet roller C to a point of anchorage on R2. The rollers C rotate about threaded pins B mounted on a spider P which is secured to a sleeve A carrying the knob K and freely rotatable about the shaft S. During slow motion tuning the rollers C rotate around the pins B in opposite directions till one of them engages a stop D carried by the pulley R2, when a solid drive is obtained between the knob K and shaft S. If the knob is then rotated in the opposite direction, fine adjustment is possible till the other roller C has moved sufficiently far. along the pin B to engage the stop D. In a modification, only one planet roller is used, a spring between the pulleys maintaining the tension in the cord.