Patent ID: 6135702
Filing Date: 2000-10-24
Classification: B25J,H01L,Y10S

Abstract:
An apparatus for preventing over-tilt of a rotating arm in a cassette loader comprising:an arm having a center aperture at one end mounted to a shaft for rotational motion of the arm and a cassette gripper at the other end for gripping a wafer cassette,a first sensor arm rigidly mounted to said shaft for moving unitarily with said rotating arm in a rotational motion for sensing a maximum downward tilt position,a second sensor arm rigidly mounted to said shaft for moving unitarily with said rotating arm in a rotational motion for sensing a maximum downward tilt position, said second sensor arm functions only when said first sensor arm fails to sense the maximum downward tilt position, anda switch for switching by said second sensor arm at a position just before said over-tilt position is reached such that power supply to said rotating arm is interrupted for stopping the motion of the arm.