GB374637A - Plug-in connection for electric switches - Google Patents

Abstract

374,637. Plug and socket couplings. PRENTICE, H. B., Primley Park Road, Alwoodley, Leeds. June 18, 1931, No. 17649. [Class 38 (i).] A switch of the kind wherein the live contact members are carried by a bar 1 rotated by a spring-controlled toggle and operating lever, is combined with a plug- and-socket coupling so arranged that the plug cannot be removed when the toggle is in the " on " position, by the action of means which are spring-retained out of action when the switch is " off, " the spring being overcome by spring- loading of the toggle when the means are put in action by the movement of the switch to " on." In the example, the means comprise a hook-ended lever 15, kept in the position shown by a spring 22, until the rotation of the bar 1 causes a pin 20 to engage in the slot 21 and cause the hook 17 to pass through the hole 13 in the earthing pin socket 11. As shown, the switch cannot be put " on " until the plug is in position, a plunger 23 being then displaced inward and the hook engaging an aperture in the earthing plug. In a modification, the plunger 23 is omitted, the switch can then be moved to " on " in the absence of the plug but the hook 17 would then prevent insertion of the plug.