GB257043A - Improvements in or relating to power digging devices - Google Patents

Abstract

257,043. Withers, J. S., (Erie Steam Shovel Co.). June 8, 1925. Scoop-arm machines.-A power digging device of the type involving a crane-like structure has a primary motor which operates the digging element directly and also actuates energy-storing means from which other movements are effected through a secondary motor or motors. As shown, an internal-combustion engine 63 drives a chain 60 which through transmission gearing 58 drives the hoisting drum 39 of the scoop arm 12, or drives the traction mechanism of the machine, the chain 60 also acting through sprocket 87 to operate a compressor 81 which forces air under pressure into containers 35, 35<a> ; this air is employed to drive a crowding engine 22 controlling the racking gear 15 of the scoop arm and an engine 7b controlling rotation of the superstructure through gearing 7 and a circular rack 7<a>, and is also used to control clutches &c. The transmission gearing 58 comprises a driven wheel 59, Fig. 4, loose on shaft 56 and pinions 141, 155 co-operating respectively with pinions 142, 157 secured respectively to drums 144, 158; friction bands under control of fluid pressure cylinders 152, 162 lock the drums 144, 158 to give a low speed or reverse drive respectively, or the gear 59 may be locked to the shaft 56 by a friction clutch 164, 165, 169 operated by admitting- fluid to a cylinder 167 whereby a high speed drive is obtained. The hoisting drum 39 is locked to its driving gear 42 by a band clutch operated by a fluid pressure cylinder 50 carried by the gear, lever 47 and eccentric pin 46. The hoisting 'drum shaft also drives the traction mechanism through clutch 64 and gearing 66, 70, 71, 74, 77. The air supply to, and exhaust from, cylinders 152, 162 and 167 controlling the transmission mechanism and the cylinder 50 controlling the hoisting drum clutch are controlled by one rotary valve 174 operated by a lever 183. The inlet pipe 94a leading to the compressor is provided with a valve 101, Fig. 7, secured to a spring- pressed piston 103; if the pressure in the receivers 36, 35a is excessive, air passes from receiver 35 through pipe 108<b> to raise a spring- pressed plunger 108 carrying a needle valve 107 and depresses piston 103 to close the compressor inlet and thereby relieve the engine. Similarly, if the speed of the engine is too low, the governor 113 opens a valve 120 to admit air from pipe 125 through pipe 126, and past check valve 127<a> to close the compressor inlet; further when the hoisting drum 39, driven at low speed, is lifting the scoop arm during digging, air passes from the pipe 153 of the low speed control cylinder 152 and through a valve 202 and pipe 203 to close the compressor inlet as before, while when the traction mechanism is in use, the valve 202 is set to connect the receiver 35<a> to the pipe 203 whereby the compressor inlet is again closed. Specification 257,044 is referred to.