GB837189A - An electrical dead-front socket outlet and a plug cap for use in combination therewith - Google Patents

Abstract

837,189. Cam-operated switches. HUBBELL Inc., H. Aug. 18, 1958, No. 26480/58. Class 38 (5). [Also in Group XXXVI] A socket for use in locations where explosive gases may be present has its spring-pressed contacts 69, 86 (Figs. 1 and 2), connected to the mains 37 and earth wire 38 through switch contacts 64, 80 which are closed to energize the socket contacts 69 by cam surfaces on insulating plate 51. Closure is effected by rotation of shaft 44 when plug member 101 (Fig. 6), has its extension 117 inserted into the socket and turned. When plug extension member 117 is inserted it depresses the socket closure plug 131 against spring 133 and the contacts 118 and earth contact 119 which it carries enter along slots in insulating body member 19 to engage contacts 69, 86. Contact 119 is wider than contacts 118 and the entry slots are of corresponding width so that the plug member can be engaged in one position only. Plug member 101 is retained in engaged position by engagement between contacts 118, 119 and shoulders 109 and also by engagement of channels in the end of extension 117 with ribs 130 on socket closure plug 131 which is itself prevented from turning. Cam-plate 51 is biased to the off position by spring 57. The inner chamber 22 within which the circuit is made and broken is sealed at the cable entry (Fig. 2) and between 22 and member 19 by hard wax seals 93 and 99.