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

A method of adjusting the position of a shear bar relative to a rotating cutter head in a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, and first and second bidirectional motors connected to move first and second ends of said shear bar, said method comprising the steps of:

• energizing said first motor to move a first end of said shear bar toward said head for a fixed interval of time or until it contacts said cutter head and then energizing said first motor to move said first end away from said cutter head a predetermined distance,
• deenergizing said first motor;
• energizing said second motor to move a second end of said shear bar toward said cutter head for a fixed interval of time or until it contacts said cutter head and then energizing said second motor to move said second end away from said cutter head said predetermined distance;
• deenergizing said second motor;
• and
• repeating each of the preceding steps until said first and second ends of said shear bar each contacts said cutter head on each of two separate energizations of the respective motors which move said ends.

In a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, and a vibration sensor for sensing contact between said bar and head, the improvement comprising:

• first means for inducing vibrations in said shear bar which may be sensed by said vibration sensor;
• an analog to digital converter responsive to said vibration sensor for producing a digital value indicative of the magnitude of output signals produced by said vibration sensor in response to vibrations in said shear bar;
• indicator means;
• and,
• microprocessor controlled means for energizing said first means to induce said vibrations, comparing said digital value to a reference value, and energizing said indicator means if said digital value is less than said reference value.

In a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, the improvement comprising:

• vibration sensing means for sensing vibrations in said shear bar;
• analog to digital converter means responsive to said sensing means for producing a digital value indicative of the magnitude of vibrations in said shear bar;
• motor means for selectively moving said shear bar toward or away from said cutter head;
• and,
• sequence control means for selectively energizing said motor means to move said shear bar away from said cutter head, sensing said digital value and adding a reference value thereto to obtain a sensitivity level value, moving said shear bar toward said cutter head while sampling said digital value for evidence of contact between said shear bar and cutter head, and stopping movement of said shear bar toward said cutter head when said sampled digital value exceeds said sensitivity level value.