Patent ID: 7708517

Claim:
A workpiece transfer method comprising: providing a first pallet containing a workpiece at a first location adjacent to a robot having a transfer device with a hand frame that is movably attached to the robot to pick up the workpiece; transporting the workpiece from the first pallet using the transfer device to a positional adjustment part in response to pre-programmed operations of the robot; performing a workpiece alignment operation to align a workpiece holding position in which the workpiece is held by the hand frame relative to the robot; setting a prescribed distance corresponding approximately to a distance between an end of the workpiece to the positional adjustment part in an adjustment direction from the end of the workpiece to the positional adjustment part when the robot is positioned at an alignment operation starting position and the workpiece holding position is aligned with a reference holding position of the robot, the prescribed distance being larger than a displacement between the end of the workpiece to the positional adjustment part in the adjustment direction when the robot is positioned at the alignment operation starting position and the workpiece holding position is misaligned with the reference holding position; and moving the robot from the alignment operation starting position towards the positional adjustment part in the adjustment direction by the prescribed distance such that the end of the workpiece contacts the positional adjustment part thereby to move the hand frame relative to the robot in a direction opposite the adjustment direction by an amount of a difference between the prescribed distance and the displacement and to align the workpiece holding position with the reference holding position.