Patent ID: 6247889
Filing Date: 2001-06-19
Classification: B25J,H01L

Abstract:
A wafer transport arm link comprising:a tray joint shaft;first and second distal end arms rotatable parallel to each other around said tray joint shaft;a wafer placement tray provided on said tray joint shaft; andfirst, second, third, and fourth magnetic rings in which a plurality of magnets are arranged in one or a plurality of ring shapes at an approximately equal angle pitch in relation to the respective axes;wherein said first and second magnetic rings are each provided rotatably having said tray joint shaft as the rotational axis, and these first and second magnetic rings are coupled to said first and second distal end arms, respectively;said third magnetic ring is magnetically coupled to said first magnetic ring and rotates along with the rotational motion of said first magnetic ring;said fourth magnetic ring is magnetically coupled to said second magnetic ring and rotates along with the rotational motion of said second magnetic ring; andthe rotational motion of said first and second magnetic rings is controlled by magnetic coupling produced between these third and fourth magnetic rings, the relative positions of the respective rotational axes of said third and fourth magnetic rings are kept constant with respect to a straight line that divides in two equal parts the angle between said first distal end arm and said second distal end arm, and the distance between the various rotational axes is equal.