GB714029A - A tuning and indicating device for combined am and fm receivers - Google Patents

Abstract

714,029. Adjusting radio apparatus. STANDARD TELEPHONES & CABLES, Ltd. Oct. 31, 1952 [Nov: 10, 1951], No. 27443/52. Class 40 (5) In a receiver employing separate tuning and indicating means for two wave-ranges (e.g. in a combined frequency-modulation and amplitudemodulation receiver), the tuning over both ranges is carried out by means of the same driving shaft and the changeover from one range to the other is so performed by means of a wavechanging. switch, that the tuning and the indication for each range are unaffected by the changeover to the other. Rotation of the wave-changing shaft 18 causes the slide 14, which is coupled to the shaft 18 via pin 16 and member 17, to move in a direction perpendicular to the shaft 18 carrying the coupling member 9 with it. The coupling member is mounted upon a splined portion of the tuning shaft 1 and is thus free to move longitudinally along this shaft but fixed as regards rotation with respect thereto. A toggle action is provided by means of the member 13. In the position shown in Fig. 1 the coupling member 9 co-operates with a pulley member 6, mounted freely upon the tuning shaft 1, so that rotation of the shaft 1 causes rotation of the pulley member and drives the tuning condenser and indicating device 8 for the amplitude-modulation range of the receiver. In the other position of the member 9, Fig. 2, it co-operates with a toothed wheel 22 driving a shaft 19. The shaft 19 is screw-threaded and has mounted thereon a member 26 which moves longitudinally with respect to the shaft upon rotation thereof due to rotation of the shaft 1. The member 26 is connected by a cord 27 to the core of a tuning inductor 28 for the frequencymodulation range. A further cord 23 wound around the shaft 19 and passing over pulleys 24 drives the associated indicator 25.