GB393097A - Improvements in or relating to devices for controlling apparatus, such, for example,as wireless receivers - Google Patents

Abstract

393,097. Control of motors. RADIO CORPORATION OF AMERICA, 570, Lexington Avenue, New York, U.S.A. June 25, 1932, No. 18005. Convention date, June 25, 1931. [Class 38 (iii).] Travelling to predetermined limits.-An electrical control device for radio-receiving apparatus &c. comprises a control shaft 6 adapted to be rotated to a preselected position or positions by an electric motor 18, a contactor or contactors 17 for controlling the motor, a cam or cams 13 frictionally mounted on the shaft and means such as spring-restrained pushbuttons 37 co-operating with slots 36 in flanges 41 on the cams for holding a cam in fixed relation to its contactor when the control shaft is rotated to change the pre-selected position, the arrangement being such that each cam is adapted to actuate its contactor so as to de-energize the motor and stop the control shaft at the preselected position without the necessity for providing a positive stop. Each contactor 17 co-operates with a fixed contact 21 for one direction of rotation of the reversible motor 18 and with a contact 22 for the opposite direction of rotation, these fixed contacts being carried by conducting bars 23 connected in circuit with the motor as shown in Fig. 2. The cams are frictionally connected to the shaft by plungers 35 of aluminium or leather held in hubs 33 of the cam discs and pressed against the shaft by garter springs 34. The motor is operated by closing any one of the switches 25 by pressing a selector button 45 and the button is held depressed until the motor stops by the opening of the circuit at the corresponding contactor 17. In this position the notch 36 of the cam disc lies directly opposite the end of the setting plunger 37 which is then pressed to lock the cam in a fixed position with the contactor open. By manual operation of a knob 8, the control shaft is then turned so that the tuning condenser 5 is in the correct position for the particular station desired and the setting button is released. Thereafter, if the tuning control shaft be in any other position, pressure of the button 45 will cause the corresponding cam member 13 to open the contactor 17 at the same setting as before. The same operation is repeated for all the other cams. The selector buttons 45 and setting buttons 37 are mounted on a panel 39 and between the two rows of buttons a readily changeable indicator card 46 is held in a channel holder 47. Extension wires 32, Fig. 2, may be provided for remote control. Specification 341,464, [Group XXXVIII], is referred to.