Patent ID: 7862050

Claim:
An apparatus for centering a workpiece, comprising: a centering tool which has a pair of action pads adapted to come into engagement with a circular part of the workpiece attracted to a chuck, a support block having the action pads mounted thereon in a fashion that the action pads are spaced away from one another, and a moving part to bear the support block for free turning on a fulcrum of the support block; wherein the centering tool includes a support plate for the support block, and the pair of action pads made in a fashion raised above the support plate; a shank fastened to a moving holder and mounted to the support plate to provide the fulcrum on which the support plate is allowed to turn freely, and a stopper fastened to the shank so as to come into abutment against recessed edges that are in opposition to one another on both sides of the stopper, and wherein as the moving part gets the fulcrum of the support block that moves towards a rotational center of the chuck, the action pads alternately come into engagement from any one side against the workpiece that is held at off-center relation in the chuck, thereby compensating the off-center of the workpiece to bring a center of the workpiece in alignment with the rotational center of the chuck.