GB467660A - Improvements in or relating to mercurial electrical cut-outs - Google Patents

Abstract

467,660. Mercury switches. JENKINS, F. T. Oct. 16, 1935, No. 28624. [Class 38 (v)] [Also in Group XXXVI] A mercury thread cut-out comprises two mercury columns 1, 2 each contained in a ceramic body and connected at their lower ends with conductors, either of which can be connected at will by a change-over switch 17 to an incoming lead not shown. The upper ends of the columns communicate with a chamber formed in a metal block 53 to which is connected an outgoing lead (not shown). As shown, column 2 is completed, the upper end being in connection with the block 53 and the lower end is connected in circuit bv switch 17. On overload, the column 2 is ruptured and the ejected mercury is deflected by a surface 3b of a plug 50 so as to fall on the other side of a ridge on block 53 to complete column 1. This can then be connected in circuit by turning the switch 17. Fig. 6 shows a form of cut-out adapted for mounting in a screw socket of the Edison type. In this form the mercury columns 1, 2 discharge into trap chambers on opposite sides of a ridge on the common terminal block 15, each trap chamber having a sloping floor causing the discharged mercury to flow to complete the other column. The lower ends of the columns are connected to contact blocks which may be selectively connected by a rotary change-over switch 17 to a central terminal 24 of a screw coupling. The outer coupling member comprises a screwed sleeve 22 rotatable but not axially movable on the body of the switch. The sleeve 22 has a flange 40 which projects beyond the body of the switch and is knurled or has a series of holes in it to enable it to be screwed into a socket while the switch is kept upright. A spring 47 connects the flange 40 with the common terminal block 15. Specification 438,190 is referred to.