Patent ID: 6466850
Filing Date: 2002-10-15
Classification: E02F

Abstract:
A shovel including a dipper for gathering material from a bank, a platform, an upwardly extending boom connected at a lower end to the platform, a sheave rotatably amounted on the upper end of the boom, a winch drum mounted on the platform, a hoist motor for rotating the winch drum, a hoist rope extending from the winch drum over the sheave and attached to the dipper, a saddle block pivotally mounted on the boom, a dipper-handle slidably supported by the saddle block, and pivotable relative to the boom by the saddle block, dipper handle moving means for moving the dipper and dipper handle away from and towards the boom, said means including a crowd motor, and crowd motor operating means for operating the crowd motor, hoist motor operating means for operating the hoist motor,speed means for monitoring the hoist motor speed, torque means for monitoring the hoist motor torque, and means communicating with said crowd motor operating means, said torque means and said speed means for moving the dipper handle toward the boom when the hoist motor speed is below a low-speed value while under high torque, and for permitting movement of the dipper handle away from the boom when the hoist motor speed is above said low-speed value or not under high torque.