GB452518A - Improvements in electric fuse switches - Google Patents

Abstract

452,518. Switches held set and freed mechanically. HOPE, V., Upton Hall, Macclesfield. March 18, 1935, No. 8300. [Class 38 (v)] The movable contacts of a triple pole switch fuse are formed of two strips bent round at one end to form contacting parts E2 while the other ends are shaped so as to be clamped by screws 12 round the end caps of cartridge fuses F. The central parts of the contacts are held together by screws 11 and are loosely mounted between pairs of insulating carrier bars J, J<1>, the three pairs of bars, together with two end frames G being clamped together by nuts 17 on transverse bars 15, 16 to form a unitary contact structure. The outer corners of each end frame G are pivoted to a pair of bell-crank levers K, K<1> pivoted to the lid and connected by links 29 so that the line joining the movable contacts keeps parallel to the line joining the fixed contacts. An operating spindle B journalled in extensions A<2> of the lid is driven with lost motion by a handle H and is connected by links C, 35 to the frame G to close the switch against the action of a spring S, the switch being held closed by oversetting the links C, 35 against a stop 39. The outward movement of levers C is limited by rubber cushions 38 on the lid. Interlock levers K<2>, K3, driven by the bell-crank levers K, co-operate with projections 41 on the casing to prevent the lid being opened while the switch is on. A headed thumb screw 42 on one of the levers K2 can be screwed in to holes in the lid to lock the mechanism in either position. When the lid has been opened and the switch mechanism moved to the on position the tail 45 of a spring-urged catch M engages a pin 46 of lever C and prevents accidental movement of the mechanism to the off position to avoid damage to an operator replacing fuses. Specification 291,518, [Class 38 (i)], is referred to.