GB503596A - Improvements in tuning indicators for radio receivers - Google Patents

Abstract

503,596. Adjusting wireless apparatus. HROMADKO, J. F. Nov. 17, 1937, No. 22575. [Class 37] A tuning-indicator for a radio-receiver comprises a band or strip wound from one roller or drum on to another in accordance with the tuning adjustment, a tuning shaft driving one or other of the rollers through gearing including ratchet or clutch mechanism in accordance with the direction of rotation thereof. The tuning knob 10 drives through gearing 19 ... 25, a shaft 26, a helically splined portion 31 of which drives the condenser (not shown) through gears 32. The gear 25 also drives through 27, 28, 33 ... 37, a shaft 38, Fig. 3, a helically splined portion 39. of which carries a double ratchet element 40 so that according to the direction of rotation of the tuning knob 10 the ratchet element 40 is moved axially and drives one or other of the gears 42, 44, which drive the respective indicator drums 17, Fig. 1, through shafts 47, 48, sprocket wheels 49, 50, and chains such as 51. The band 15 carrying the station, wavelength or other indicia in columns, Is kept taut by spring-pressed arms 57 bearing on the flanges of the drums 17 and is viewed through an aperture 18 in the casing 12 and a corresponding aperture in the receiver cabinet. A moving mask controlled by the wave-change switch may be used to obscure all but the appropriate column of indications, or the various colunms could be selectively illuminated under the control of the wave-range switch. In the embodiment shown, however, the appropriate column of indications is brought into register with the panel viewing aperture by sliding the upper casing 12 relative to the lower casing 11 secured to the receiver chassis. This is effected by the wave-change-switch knob 63, through a cord drive 64, gearing 67, 68, 69 and a rack 70 on the casing 12.