GB537008A - Improvements in press-button operated tuning devices for radio receiving apparatus - Google Patents

Abstract

537,008. Tuning wireless receivers. FABBRICA ITALIANA MAGNETI MARELLI. Sept. 14, 1939, Nos. 25863 and 25864. Convention dates, Sept. 16, 1938 and June 12, 1939. [Class 40 (v)] [Also in Groups XXXV and XXXVI] In radio receivers of the type in which the receiver is pre-tuned to a number of selected stations by sets of coils each coil having within it a magnetic core the pre-set tuning being effected by relative adjustment of the cores and coils and the required set of coils for the particular station desired being thrown into circuit by the operation of a push button the coils are mounted on insulating sleeves supported in a box in which the whole tuning unit is contained and in which screws are journalled, the displacement of the cores being effected by rotation of the screws. The cores 10 slide in guiding sleeves 7 around which the coils 8, 9 are wound. The cores are adjusted individually by rotating screws 15 in the arms 14 of a slide which is itself adjustable by rotating a threaded screw 12 by means of its head 121. The required set of coils is thrown into circuit by depression of a rod 19 by means of its push button 16 so as to close the switch 17, 18. In a modification, Fig. 6, the cores 10 are connected by means of resilient rods 31 to screw threaded sockets 32 formed in the arms 341 of a slide 34 adjustable by means of a nut 13 on a threaded rod 12. The slide 34 is provided with a flattened extension 36 projecting through an aperture 37 the projecting portion being calibrated so that the setting of the cores may be determined.