GB776708A - Improved push button tuning apparatus for radio sets - Google Patents

Abstract

776,708. Adjusting radio apparatus. RANDERSON, K. D. June 29, 1955 [June 26, 1954], No. 18794/55. Class 40(5) In push-button tuning apparatus, each push-button comprises a member which, when the push button is depressed, engages pins projecting from the sides of a respective disc mounted upon the shaft of a rotary capacitor and thus rotates the capacitor to a position depending upon the angular setting of the disc upon the shaft. Each push button comprses a sliding cross-piece 8 which is supported by guide rods 9, 10 and biased outwardly by a spring 15, each cross-piece 8 having end surfaces 8e, 8h and being also provided with projecting tongues 8d, 8g which are disposed on opposite sides of the plane of the member 8. Co-operating with each cross-piece is a disc 17 which is mounted and held frictionally upon the shaft 3 of a rotary tuning capacitor 2. Each disc 17, Fig. 5, is provided with projecting pins 18, 19, 20, 21, the pins 20, 21 being longer than the pins 18, 19 and the pin 21 being arranged on the rear side of the disc as seen in Fig. 5. Assuming the disc 17 is disposed on the shaft 3 as shown in Fig. 1 when the corresponding push button is depressed, the tongue 8g engages the long pin 20, Fig. 6 (not shown) and pushes the disc round in an anti-clockwise direction until the pin 20 moves out of the path of the tongue 8g, by which time the pin 18 has come into a position in which it is engaged by the endface 8h of the cross-piece 8, Fig. 7 (not shown). Being short, the pin 18 is able to move without obstruction from the tongue 8g, which as stated above does not lie in the same plane as the main portion of the cross-piece, and hence the disc continues to rotate with further depression of the push-button until the pin 19 meets the end-face 8e, Fig. 8, when further movement of the push-button or of the disc is impossible. This position of the disc represents the desired setting of the capacitor. In the operation described above the tongue 8d and the pin 21 were not involved. When however the initial and desired settings of the shaft are such that clockwise motion is required, the disc will have such a setting with respect to the member 8, that the tongue 8d, passing behind the disc as seen in the figures engages the pin 21 to commence the clockwise motion, this being subsequently taken over by the endface 8e engaging pin 19. The shaft 3 is provided with a knob, Fig. 3 (not shown), for effecting manual adjustment. When it is desired to set a particular push-button to a given radio station, the button is held depressed while manual adjustment of the capacitor is effected, the disc then taking up the appropriate angular setting on the capacitor shaft 3.