Patent ID: 6070480
Filing Date: 2000-06-06
Classification: B23Q,F16H,Y10T

Abstract:
A differential motor drive for an XY stage comprising:a fixed base with a first surface and with a first edge and a second edge opposite the first edge;a first motor having an axis of rotation, said first motor being mounted to the fixed base on the first surface along the first edge;a second motor having an axis of rotation, said second motor being mounted to the fixed base on the first surface along the first edge so that said second motor is located a spaced distance from said first motor;a first pulley having an axis of rotation, said first pulley being mounted on the first surface along the second edge of said fixed base;a second pulley having an axis of rotation, said second pulley being mounted on the first surface along the second edge of said fixed base so that said second pulley is located a spaced distance from said first pulley, wherein said first and second motors and said first and second pulleys form a rectangular configuration and wherein said first pulley is opposite said first motor and the axis of rotation of said first and second motors and said first and second pulleys are parallel;a first moveable platform, with a first edge and a second edge opposite the first edge, said first moveable platform moveably mounted to said fixed base between said first and second motors so that the first edge of said first moveable platform is substantially parallel and adjacent the first edge of said fixed base;a third pulley having an axis of rotation, said third pulley being mounted along the first edge of said first moveable platform;a fourth pulley having an axis of rotation, said fourth pulley being mounted along the first edge of said first moveable platform so that said fourth pulley is located a spaced distance from said third pulley, and so that said third pulley is closest to said first motor;a fifth pulley having an axis of rotation, said fifth pulley being mounted along the second edge of said first moveable platform;a sixth pulley having an axis of rotation, said sixth pulley being mounted along the second edge of said first moveable platform, wherein said third, fourth, fifth, and sixth pulleys form a rectangular configuration with said fifth pulley being located opposite said third pulley, and wherein the axes of rotation of said third, fourth, fifth, and sixth pulleys are substantially parallel to the axes of rotation of said first and second motors and said first and second pulleys;a first belt routed from said first motor to said third pulley and then to said fourth pulley and then to said second motor and then to said second pulley and then to said sixth pulley and then to said fifth pulley and then to said first pulley and then back to said first motor;a second moveable platform moveably mounted to said first moveable platform, wherein the second moveable platform is attached to said first belt between said third and fourth pulleys so that when said first and second motors rotate in the same direction said first moveable platform remains substantially stationary and said second moveable platform translates substantially parallel to the first edge of said fixed base;a secondary flexible drive member forming a loop from the fifth pulley around the sixth pulley, and where the second moveable platform is attached to the secondary flexible drive member between the fifth and sixth pulleys on the side of the loop closest to the second edge of the first moveable platform.