GB379063A - Improvements in combined switches and wall connectors - Google Patents

Abstract

379,063. Plug couplings. LUNDBERG & SONS, Ltd., A. P. and PEGG, G., 477, Liverpool Road, Holloway, London. July 23, 1931, No. 21073. Addition to 327,021, [Class 38 (i), Electric couplings &c. [Class 38 (i).] In a combined switch and plug coupling of the type wherein the switch cannot be switched on until the plug has been pushed home, and the plug cannot be withdrawn until the switch has been switched off, the plug part has standard plug pins, i.e. plain unmodified solid or split pins, and is gripped in the socket by a cam device. As shown, a socket 7 for an earthing pin 19 is formed with a slot 11 in which is pivoted at 13 a cam 15 the edge 17 of which is clear of the socket when the switch is off. The tail 21 of the cam 17 is received in a recess 24 in a locking plate 23 which forms an extension of a U-shaped yoke 25 pivoted on the pivots 27 of the blades 29 of a tumbler switch 3. When the switch is put on, the.yoke 25 and plate 23 are rocked about the pivots 27 by the action of the blades 29 on pins 31 which lie in notches 33 in the yoke 25. Until the plug has been pushed home, the switch is locked by a lever 43 pivoted at 45 and extending into a notch 49 in the plate 23. The lever 43 carries a spring 51 connected at both ends to the lever and passing through a hole in the tail-piece 21. When the plug is pushed home, the lever 43 is depressed, and the plate 23 is then free to move, so that the switch can be put on. At the same time, the spring 51 is stressed, so that the edge 17 of the cam is caused to grip the plug pin, which cannot then be withdrawn until, by turning off the switch, the cam has been returned to its inoperative position by contact of the plate 23 with the tail-piece 21. Fig. 5 shows a modified construction in which the lever 43 is replaced by a bar 61 fixed to a plunger 63 in the socket. Until the plug has been inserted, the free end of the bar 61 lies in the notch 49 of the plate 23 and locks the switch. Insertion of the plug depresses the plunger 63 and bar 61 against the action of a spring 67, and unlocks the switch. The spring 51 is normally in stressed condition and is connected to a projection 69 on the side of the socket block. A rotary switch may be provided instead of a tumbler switch, and the cam may be caused to grip one of the current-carrying pins.