Patent ID: 8209096
Filing Date: 2012-06-26
Classification: E02F,G01G,G01L

Abstract:
1. A method of determining a crowd length offset for a shovel including a base, a dipper, a boom pivotally mounted on the base, a hoist rope extending from the base to the dipper and wrapped over a sheave mounted on the end of the boom, and a dipper arm supporting the dipper on an end thereof, the dipper arm being pivotally mounted on the boom, a crowd resolver mounted on the boom and responsive to record an arm extension and retraction reading, where arm length is equal to arm offset plus arm gain times the crowd resolver reading, the method comprising: automatically recalibrating a dipper position information, storing maximum values of the crowd resolver, using the known length of the arm at maximum extension positions, calculate offset value for each resolver maximum value, obtaining an array of readings from the crowd resolver to calculate an array of calculated rope wrap angles, obtaining an array of rope wrap angles from another device for measuring the rope wrap angles, and selecting the crowd length offset that minimizes a difference between the two sets of calculations.