Patent ID: 7712228

Claim:
A method for effecting automatic centering of an annular workpiece on a surface having a rotational center, comprising: arbitrarily positioning an annular workpiece on a rotating surface, the annular workpiece possessing a center; applying a support to the workpiece by contacting the workpiece with a first contact member and a second contact member that are spaced apart from one another and that are reciprocatingly movable towards and away from a rotational center of the rotating surface, wherein at least one of the first and second contact members comprises a driven rotary element; gradually retracting the first and second contact members away from the rotational center of the rotating surface until the workpiece is unaffected by the contact members during one revolution of the rotating surface, whereby the workpiece is centered so that the center of the workpiece coincides with the rotational center of the rotating surface; and driving the rotary element in a direction and at a speed for counteracting a friction force acting on the workpiece, which friction force otherwise would result in a force component acting upon the workpiece urging the workpiece to move radially outwardly from the rotational center of the rotating surface.