Patent ID: 7167805

Claim:
A reference position correcting device for a conveying mechanism including: a moving member disposed in a conveying vessel, the moving member being capable of moving in a horizontal moving direction; a rotary table attached to the moving member, the rotary table being capable of turning in a horizontal turning direction and moving in a vertical direction; two arm mechanisms attached to the rotary table through vertical rotary shafts spaced apart from each other, the arm mechanisms being capable of bending and stretching in a horizontal operating direction; and picks attached on distal ends of the respective arm mechanisms, each for holding an object to be conveyed; said correcting device comprising: a light emitter fixedly positioned on the conveying vessel, for emitting a sensing light beam in a horizontal direction crossing the moving direction of the moving member; a light detector fixedly positioned on the conveying vessel to receive the sensing light beam, for detecting a light-transmitting state and a light-shielding state of the sensing light beam; a light-shielding member attached on the rotary table, for switching the sensing light beam between the light-transmitting state and the light-shielding state in compliance with a movement and a turn of the rotary table; and correcting means for correcting reference positions of the rotary table in the moving, vertical, and turning directions, and for correcting a reference position of the arm mechanism in the operating direction, based on a detection by the light detector about the light-transmitting state and the light-shielding state of the sensing light beam switched in compliance with the movement and the turn of the rotary table.