GB858307A - Radio tuning mechanisms - Google Patents

Abstract

858,307. Push-button tuning mechanisms. PLESSEY CO. Ltd. May 20, 1957 [May 18, 1956], No. 15642/56. Class 40(5). [Also in Group XXXV] A tuner particularly for television receivers comprises an inductor the turns of which are intercolated with a set of non-magnetic, conductive plates, movable by means of a push-button arrangement. As shown, the inductor comprises a number of loops 12 retained in a plate 11 and connected in series by means of straps 13. The tuning is varied by means of copper plates 15 mounted on a carriage 14 and pivoted at 17. A pair of treadle bars 21 are coupled to the movable carriage 14 via members 22, 24. The setting of the treadle bars 21 and hence the tuning of the inductor 12 is adjustable by means of plates 20 pivoted to rods 19 carrying push buttons 18 but preset at a given angle corresponding to the television channel required. The plates 20 are locked against the flat rods 19 by means of a spring strip 19a, the end of which is forced into a tapered sleeve 26 by pressure on the push button 18 to the left. When it is desired to reset any push button 18 to a different channel, the carriage 14 is first adjusted manually to the required channel, the appropriate push button 18 is then withdrawn to the right as shown in Fig. 2, releasing the plate 20. When the push button 18 is depressed the plate 20 takes up the angle between the treadle bars 21 and the spring strip 19a is forced into the tapered socket 26 thus locking the plate 20 in position. Fine manual tuning. Fig. 3 shows a modification in which a clutch plate 33 is spring biased against the bracket 16. Fine manual tuning is available by means of a knob 34 and a friction wheel 31. When any push button is operated a cam surface 19b at the end of the push-button rod 19 displaces a member 38 to the left to disengage the clutch. Specification 858,306 is referred to. Reference has been directed by the Comptroller to Specifications 521,817 and 770,301.