GB479431A - Improvements in and relating to electrical remote control apparatus - Google Patents

Abstract

479,431. Electromagnetic relays. WHITELEY, A. H. July 31, 1936, No. 21200. [Class 38 (v)] [Also in Group XL] The output volume of an amplifier or radio receiver and the current supply to the amplifier or receiver are controlled electrically from a distance, the latter control being operable only when the volume control is at or near its minimum setting. Fig. 1 shows a relay of the kind which latches and releases on consecutive energizations and comprises an armature I carrying at its free extremity a hooked wire 16 which engages in a cam track between two members 17, 18. Alternatively, a starwheel latching-release system may be employed. On energization of relay coil 13, armature 11 is attracted to close contacts 19 which then remain closed until the relay is again energized. The relay unit also includes a battery 20, terminals 24, 25 and the receiver mains supply plug 27. Fig. 3 shows the controlled circuits, the terminals 24 being connected to the loudspeaker terminals of a radio receiver or amplifier to which a distant loud-speaker LS is connected. Depression of push-button 22 on the local relay unit 23 at the remote point closes the mains supply 26 to the receiver supply plug 27. In a modification, an auxiliary relay is employed to close the contacts of relay 13, Fig. 4 (not shown). The low-frequency volume may be controlled in known manner by a potentiometer shunted across the loud-speaker leads, such as a resistance winding 31,Fig. 6, tappings from which are brought out to contacts engaged by a rotary switch and knob 34. The rotor spindle is drilled to receive a rod 38 terminating in a spring-loaded press-button 39 which when depressed closes a pair of fixed contacts 35 to switch the set on or off as at 23 of Fig. 3. The bridging contact 36 is mounted on an insulating plate 37 mounted on rod 38 and passing through an aperture in an L-shaped member 40 which rotates with the knob 34. The arrangement is such that the member 37 pivots about member 40 to move contact 36 inwards (to the left) only in the minimum position of the volume-control; depression of knob 39 in all other positions has no effect.