Patent ID: 7222804

Claim:
An arrangement for adjustment in the position of a shearbar relative to knives of a chopper assembly, the arrangement comprising: a first adjusting drive configured to move a first end of the shearbar with respect to the knives of the chopper assembly; a second adjusting drive configured to move a second end of the shearbar with respect to the knives of the chopper assembly; a spacing measurement arrangement configured to provide information regarding a position of the shearbar with respect to the knives; and a control arrangement connected to the first adjusting drive, the second adjusting drive, and the spacing measurement arrangement to control the first and second adjusting drives; the control arrangement being configured to cause the first adjusting drive to position the first end of the shearbar at a predetermined first spacing from the knives, the control arrangement configured to cause the second adjusting drive to position the second end of the shearbar with respect to the knives such that the spacing measurement arrangement indicates that the second end of the shearbar is equal to or less than a threshold distance from the knives while the first end of the shearbar is at the predetermined first spacing from the knives; the control arrangement being configured to cause the second adjusting drive to position the second end of the shearbar at a predetermined second spacing from the knives, the control arrangement configured to cause the first adjusting drive to position the first end of the shearbar with respect to the knives such that the spacing measurement arrangement indicates that the first end of the shearbar is equal to or less than a second threshold distance from the knives while the second end of the shearbar is at the predetermined second spacing from the knives; the control arrangement being configured to cause the first and second adjusting drives to position the first and the second ends of the shearbar with respect to the knives such that the first and second ends are respectively located first and second desired distances from the knives, the first and second desired distances based on the information regarding the position of the shearbar with respect to the knives when the first and second ends of the shearbar are at the first and second threshold distances, the first and second predetermined spacing from the knives being respectively greater than the first and second desired distances from the knives.