GB373402A - Improvements relating to combined electric switch and fuse gear - Google Patents

Abstract

373,402. Snap-action switches. DOBSON, E. and FOSTER ENGINEERING CO., Ltd., Apex Works, South Wimbledon, London. May 18, 1931, No. 14637. [Class 38 (v).] A double pole switch-fuse has contact blocks on the base adapted for engagement by the clips of fuse holders carried by the cover thus ensuring that the fuses are disconnected when the cover is removed. The switch comprises a moulded insulating case 1 in which is mounted an insulating contact spindle 3 having a bearing in the casing at one end 6 and formed at the other end with a spigot which engages a central recess in a handle 4 which also has a bearing in the casing. U-shaped movable contacts, embedded in the contact spindle, co-operate with contacts on the base which are connected to contact blocks. Two pairs of these contact blocks are adapted to engage with the clips 13 of fuses which are passed through tunnels 18 in ridges on the insulating cover 2, which is held in position by a screw 19. On removal of the cover the fuses are thus disconnected. The snap action mechanism (not shown) comprises a spring coiled round the spigot end of the contact spindle and having its ends engaged by projections on the handle and spindle so that movement of the handle is transmitted to the spindle. A spring pawl 23 engages a recess in the spindle 3 to hold it until the spring is sufficiently strained, when a cam on the handle lifts the pawl, allowing the contact spindle to move rapidly. A projection 29 on the spindle 3 engages fixed stops on the casing to limit the movement of the spindle. Hooks or stumps may be provided on the lid to engage the movable contact member to lock the casing while the switch is on.