Patent GB-544095-A (GB)
Title: Improvements in or relating to radio-receiving apparatus comprising at least two adjustable members having a common driving device
IPC: H03J5/14
Filed: 1940-06-10
Abstract: 544,095. Tuning wireless sets. PHILIPS LAMPS Ltd. (Naamlooze Vennootschap Philips' Gloeilampenfabrieken). June 10, 1940, No. 10105. [A Specification was laid open to inspection under Sect. 91 of the Acts, Dec. 14, 1940.] [Class 40 (i)] [Also in Groups XXIV, XXXVI and. XXXVII] In a wireless receiving set, a motor 23 drives a shaft 1 first in one direction for determining the setting of a slidable-electrode condenser for tuning and then in the other direction for controlling a wave-changing switch. The shaft 1 carries a pin 3 co-operating with an inclined slot 4 in a clutch-member 5 so that the initial rotation in the first direction shifts the latter to the left to clutch to the shaft a sleeve-member 8 which drives a gear-wheel 17 through a friction coupling 18. A roller 25 on the shaft 26 of the condenser bears on a cam surface 24 on the wheel 17 so that continued rotation drives the shaft 26 to an extreme position whereupon the movement of the wheel 17 is stopped by the engagement of a roller 27 thereon with the member 8 which then imparts its movement through the roller 27 to a drum 28 until an insulating part 35 engages one of a number of wipers 32 corresponding to an operated push-button. The motor 23 now reverses as described later, and the condenser shaft is driven by a spring until it strikes one of a number of stop pins 29 of varying length carried by the drum 28. The wheel 17 returns to normal and opens a contact 36 which disconnects the magnet if no control of the wavechanging switch is necessary. Since the spring of the condenser drives the motor, the clutchmember 5 is not affected until the wheel 17 is at rest, after which it moves to the right to clutch a gear-wheel 12 to the shaft 1. A disc 43 is thus driven through a crank 38 until an insulating part 44 engages an appropriate one of four wipers 45, when the motor circuit is opened, the wave-changing switch being now in the proper position. The push-buttons such as 80, 81, Fig. 5, which have a common lock 94, are arranged between two rails 98, 99 provided with inclined notches 100. Each push-button has a plate 95, Fig. 6, with two protrusions 96, 97 which may be placed in any one of four positions so that when the button is depressed either of the rails 98, 99 is moved in either longitudinal direction to operate one of four sets of contact-springs 82-85 connected to the wipers 45. Four push-buttons, one for each wave range, are provided for bringing the condenser under the control of a hand-knob 52, Fig. 3. The drum 28 is set to a position in which no stop pin is operative, and the return of the wheel 17 allows a rocking plate 57 on a shaft 49 to turn until a pawl 58 falls into a deep notch 63 in a disc 61 integral with the drum 28, thereby withdrawing a rod 56 sufficiently to permit a spring-controlled stop 54. to move into the path of a lug 64 on the condenser shaft. The stop 54 is carried by a nut 53 which moves along a screw-threaded portion of the shaft 49 as the knob 52 is turned. The shaft of the knob 52 is hollow so that the stop pins 29 may be adjusted by means of a screw-driver passed there-through. 'The circuit of the motor 23 is controlled by a pair of relays which are connected up by the push-buttons over the drum 28 and the disc 43 respectively. The contact 36 controlled by the wheel 17 ensures that the motor is energized in the reverse direction until the wheel returns to normal when no movement of the wave-changing switch is necessary. Separate sets of push-buttons with a change-over switch are provided for local and remote control. Specification 543,574 is referred to.