Method and apparatus for adjusting a shear bar relative to a cutter head.

摘要

Under the control of a microprocessor (200) first and second motors (110, 112) alternately drive first and second ends (A, B) of a shear bar (102) for adjusting the position of the shear bar relative to a cutter head (100). The shear bar (102) is adjusted so that it is substantially parallel to the cutter head (100) even though the cutter head and shear bar may not be parallel at the time the adjustment is initiated. A knock sensor (118) is provided for sensing impacts between the cutter head (100) and the shear bar (102), the knock sensor output signal being converted to a digital value for controlling the adjusting sequence. A knocker (122) may be provided for inducing vibrations in the shear bar (102) to thereby test the operability of the knock sensor (118) and its output circuitry. The sensitivity of the adjustment system to the output of the knock sensor (118) is set automatically before and adjustment sequence begins to account for variations in the knock sensor, its output circuitry, and "noise" vibrations induced in the shear bar by normal machine operation.