GB254592A - Improvements in electrical plug-switches - Google Patents

Abstract

254,592. Row, F. W. Nov. 16, 1925. Two-part couplings combined with electric switches. - The plug 3, Fig. 2, of a two-part coupling is connected by wires 5 to a stage-lighting circuit &c., the wires passing through the hollow wooden body thereof and being secured by screws 8 to a pair of diametrically-projecting contacts 4. The plug is inserted in a circular aperture 12, Fig. 3, in the top of a casing 9, the contacts 4 passing through gaps 13 therein and through channels 16 in a fixed insulating block 15 into gaps 25 a rotatable insulating ring 23. The plug is then rotated clockwise, carrying with it the ring 23 and the contacts 4 engage between pairs of contact plates 20 secured in spaced relation by distance-pieces 19 and screws 22 on the underside of the block 15. As the supply cables are laid in channels 17 in this block and are connected to the screws 22, connection is effected between these cables and the wires 15. The plates 20 are of arcuate shape and are located in a circumferential groove 24 in the ring 23, which serves to cover the contacts when the plug is withdrawn. The ring is retained in place by a spring 26, and another spring 30 presses on an axially-movable block 29, which by engaging with the bottom of the plug 3 serves to eject the latter when it is turned counter-clockwise. In a modified construction, the block 29 is secured against rotation, and in its raised position engages the ring 23 by splines so as to prevent rotation of the latter. Thus the contacts cannot be uncovered until the plug has been inserted so as to depress the block 29.