Improvements in and relating to safety signalling appliances for the guidance of enginemen at collieries and the like

摘要

168,761. Leitch, J. July 31, 1920. Mine and colliery signals.-In mine-signalling apparatus a bell-crank lever a, having one arm a2 attached by wire to the visual signalling apparatus, is placed over the bell hammer lever g in such a way that a slight movement of the latter is sufficient to transmit a signal to the visual signalling-apparatus. The bell-crank lever a is fulcrumed at b to a vertical standard consisting of two inverted U-shaped supports c bolted to a base-plate e. The arm a3 carries a helical spring a5 and may carry a sleeve weight a4.