Drive arrangement for rotary shredding apparatus

摘要

A rotary shredder for waste materials has a pair of counterrotating cutting shafts, each of which mounts a series of spaced-apart disc-type cutters. The cutters on one shaft extend into the spaces between cutters on the other shaft so that the cutters on the two shafts coact to shred material fed therebetween. The two shafts are driven by a reversible radial piston hydraulic motor through a gear train arranged to rotate one cutter shaft at twice the speed of the other. The hydraulic motor is driven by an electric motor-driven fixed or variable displacement pump. A flow-reversing valve in the hydraulic motor control circuit controls the direction of fluid flow through the hydraulic motor. The reversing valve is electrically actuated automatically by a fluid pressure-operated switch to reverse flow and the direction of rotation of the cutters to prevent jamming whenever fluid pressure in the motor circuit rises to an abnormally high level. Upon detecting high pressure, the switch energizes a time delay relay which closes a relay contact to energize a solenoid which actuates the flow-reversing valve for a predetermined time period, after which the valve shifts to its normal position to operate the hydraulic motor in its normal directional mode to resume shredding.