Workpart centering mechanism for a chuck
First Claim
1. In combination with a workpart chuck having a chuck axis of rotation for rotating a workpart about its workpart axis when the axes are substantially aligned, apparatus for centering the workpart on the rotating chuck from an initial offset position where the workpart axis moves in an eccentric path relative to the chuck axis, comprising:
- a centering member movable relative to the chuck axis as the chuck rotates the workpart and engageable with the workpart for moving the workpart axis toward the chuck axis with said eccentric path changing as the workpart moves, means for sensing the extent of eccentric movement of the workpart as the centering means moves the workpart and generating a signal that is indicative of the extent of said eccentric movement, and means for moving the centering member toward the chuck axis until said signal reaches a predetermined value indicative that the workpart is rotating substantially about its own workpart axis.
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Accused Products
Abstract
A workpart chuck is provided with a centering member that is movable toward the axis of rotation of the chuck as the chuck rotates the workpart in an eccentric non-centered position. As the centering member moves the workpart, a sensing device senses the extent of changing eccentric movement of the workpart and generates an electrical signal that is indicative of the extent of such eccentric movement. The workpart is moved toward the chuck axis until the signal reaches a predetermined value indicative that the workpart is rotating about its axis; i.e., the workpart axis and chuck axis are substantially coaxial. The centering member is offset slightly relative to the chuck axis of rotation to assure that excessive movement of the centering member placing the workpart center beyond the chuck axis of rotation will not result in the workpart being driven to an extremely eccentric position and possibly even off the face of the chuck. The sensing device will detect a sudden shift of the workpart position relative to the centering member indicative of such movement beyond center, whereupon the control system will cause the centering member to retract a small distance and advance in a new attempt to center the workpart.
11 Citations
21 Claims
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1. In combination with a workpart chuck having a chuck axis of rotation for rotating a workpart about its workpart axis when the axes are substantially aligned, apparatus for centering the workpart on the rotating chuck from an initial offset position where the workpart axis moves in an eccentric path relative to the chuck axis, comprising:
a centering member movable relative to the chuck axis as the chuck rotates the workpart and engageable with the workpart for moving the workpart axis toward the chuck axis with said eccentric path changing as the workpart moves, means for sensing the extent of eccentric movement of the workpart as the centering means moves the workpart and generating a signal that is indicative of the extent of said eccentric movement, and means for moving the centering member toward the chuck axis until said signal reaches a predetermined value indicative that the workpart is rotating substantially about its own workpart axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- 10. A method for centering a workpart on a rotating chuck comprising the steps of rotating the chuck with the workpart geometrical axis offset from the chuck axis of rotation so that the workpart axis moves eccentrically, moving the workpart axis toward the chuck axis as the chuck rotates such that the eccentric movement changes as the workpart axis is moved toward the chuck axis and generating a signal that is indicative of the extent of eccentric movement as the workpart axis moves toward the chuck axis.
Specification