Patent GB-742939-A (GB)
Title: Improvements in the press button tuning of radio receivers
Inventor: FEARN ALFRED ARTHUR
IPC: H03J5/12
Filed: 1953-02-10
Abstract: 742,939. Adjusting radio apparatus. WORLD RADIO, Ltd. Feb. 26, 1954 [Feb. 10, 1953], No. 3746/53. Class 40 (5). In a push-button radio receiver of the kind wherein the push-buttons each act, when depressed, upon a common tuning means, such as a set of ganged capacitors or inductors, each push-button unit comprises a slide 2, an adjustable member 3, a locking lever 14 and a pushbutton 1 so arranged that normally the adjustable member is held locked (Fig. 2, not shown) by the lever 14, but that when the push-button 1 is withdrawn from the slide 2 and the lever 14 as shown in Fig. 3, the member 3 is released. The member 3 (see Fig. 1) is of substantially semi-circular shape and has projecting lugs which engage with the tuning means when the unit is depressed, depression of the unit when the member 3 is locked serving to effect tuning of the receiver, while depression when the member is unlocked positions the member in accordance with the tuning of the receiver. Continued depression of the push-button 1 in the latter case causes the lever 14 to assume its locking position, thus holding the member 3 at its new setting. Fig. 5 shows the assembly of five push-button units A ... E together with associated manual-tuning apparatus. Manual tuning is provided by a knob 76 which operates through gearing 77, 78 and normally engaged clutch plates 79, 81 to rotate pinion 75 and thus rotate gear-wheel 74 which drives a transversely sliding bar 47. Tuning members comprising ferromagnetic cores 71 movable within inductors 68 are attached to the bar 47 for movement therewith; also attached to the bar are longitudinally extending rods (not visible in the Figure) which engage with the adjustable members 3. When one of the pushbuttons units A ... E is depressed the corresponding projection 5b (see Fig. 1) engages a projection 97 on a bar 95, thus urging the bar upwardly as shown and separating the clutch plates 79, 81 by virtue of an arm 96 projecting from the bar. 95 and bearing upon a rod 87 fixed to the plate 79 and extending through the plate 81 and pinion 75. Consequently, with the member 3 locked, further depression of the push-button unit positions the bar 47 in accordance with the setting of the member 3 and adjusts the receiver tuning correspondingly. When it is desired to alter the tuning provided by any one push-button unit, the corresponding button is first pulled outwards as far as it will go. This causes the button to move outwardly with respect to the remainder of the unit, thus taking up the position shown in Fig. 3 and releasing the adjustable member 3. The unit is then depressed whereupon the member 3 engages the longitudinally extending rods attached to the bar 47 and, being unlocked, takes up a position determined thereby, the position of the bar having been previously adjusted to give the desired tuning by means of knob 76. Upon further depression of the unit the slide 2 engages a stop and continued depression consequently restores the button 1 to its normal position with respect to the slide 2 and locking lever 14, whereupon the member 3 is locked in its new position. Tuning indicators. A pointer 107 positioned at one end of a lever 109 and depending normally thereupon moves over a scale arranged immediately above the push-buttons. A pin at the other end of the lever moves in a slot 112 formed in a bracket secured to the apparatus while a bell-crank lever 114 pivoted at 115 to a fixed bar 43 is also pivoted at 116 to the lever 109. The other end of the bellcrank lever comprises a pin 117 sliding in a slot 118 in the sliding bar 47. Thus movement of the bar to alter the tuning causes movement of the pointer 107, the linkage being such that substantially linear movement ensues. Wave band switching. Wave band switching is effected by rotation of shaft 98 which is rotated by means of a cranked lever 101 which is engaged by the end of the slide of pushbutton unit E when the latter is depressed. When the unit E is depressed to select a second wave-band the lever 101 is rotated and is then held in this position by a plate 103 which latches therewith. However on depression of any of the remaining push-button units, the tip of the corresponding slide pushes upon the plate 103, thus unlatching the lever 101 which returns to its original position under the action of a spring, thereby restoring the tuning to the original wave-band.