294 MODERN GASWORKS PRACTICE
bolted to the channels of the hanging frame. The current for the two motors is co 11 eet ed from two overhead bare copper conductors by means of two trolley poles fixed near the top of the machine frame. From these poles the current is led by means of stranded copper insulated conductors carried in steel conchiits to the switch and connection box on the platform. The connection box is fitted with the necessary double pole switch, automatic circuit breaker and distributing fittings. From this box the current is led to the reversing controller of the hoisting and pro-pelling motor and to two bare conductors strained vertically on one side of the machine frame. The motor driving the telescopic ram collects its current from these conductors by means of two short trolley poles fixed to the hanging frame. An automatic cut-oft is arranged so that the controller is returned to the “ off ” position at each end of the stroke of the ram, also wlien th.e hanging frame is moved to the top and bottom positions. A foot brake is attached to the machine for bring-ing it to rest exaetly in front of the retort which is to be discharged.
Fig. 212.— Drake’s Pusher, showing Constbuction ok thb Chain.