GB492912A - Improvements in, or relating to, electrical couplings of the plug-and-socket type - Google Patents

Abstract

492,912. Two-part couplings. CRABTREE & CO., Ltd., J. A., McLOUGHLIN. H. F., and HARRISON, B. G. April 9, 1937. No. 10079. [Class 38 (i)] A range of plug-and-socket fittings have the spacing and dimensions of the contacts the same for all ratings, one socket and the corresponding plug of each member having means that obstructs the engagement of the members so that only plugs of the same or less rating than any specified socket can be inserted therein. The spacing and diameter of the contacts may be the standard dimensions of. the 15 amp. rating and each lower rating has a projection h<1>, h<2>, h<3> partially obstructing the earth socket f<3>. The position of the projection varies with the rating of the socket, and the corresponding earth pin e<3> has grooves i<3> corresponding only to the projection of its own socket and to those of higher rating. The projections h<1> . . . h<3> may be carried on plates g<1> . . . g<3> for insertion in a slot in the socket or in the cover, or between the two. Each plug member may be distinguished by a mark or colour, each socket member bearing the marks or colours of all the plugs that can be inserted therein. Other means for obstructing the entry of the plugs into the sockets may be employed, such as hollow plugs coacting with cores in the sockets rendered selective by variation of diameter or eccentricity, or slotted plugs coacting with transverse blades in the sockets.