Patent ID: 6486574
Filing Date: 2002-11-26
Classification: G05D,Y10T

Abstract:
A small footprint vertical lift and rotary positioning stage comprising:a base plate; first and second side plates perpendicular to the base plate and fixed near opposite edges of the base plate; a bottom wedge and a top wedge, said bottom wedge having a bottom face parallel with the base plate and an upper face forming an angle alpha with the bottom face, said top wedge having a top face parallel with the base plate and a lower face forming an angle alpha with the top face; a first linear bearing between the base plate and the bottom face of the first wedge; a second linear bearing between the upper face of the bottom wedge and the lower face of the top wedge; cam grooves in the first plate having cam surfaces for receiving cam follower rollers journaled to the top wedge for constraining the motion of the top wedge in a direction perpendicular to the base; a brushless linear motor comprising an armature winding fixed to the second side plate and a rare earth magnet track fixed to the bottom wedge for moving the bottom wedge back and forth along a path constrained by the first linear bearing and in consequence thereof raising and lowering the top wedge constrained by the cam surfaces and cam rollers; a linear encoder comprising an encoder reader fixed relative to the base plate and an encoder scale fixed to the bottom wedge extending parallel to the base plate and the direction of travel of the bottom wedge; a rotating stage having a circular plate fixed to the top surface of the top wedge; a circular table rotatably mounted to the circular plate and having a first cylindrical flange extending downward from a segment of the circumference of the circular table; a bracket mounted on the side of the top wedge, said bracket supporting an upwardly extending second cylindrical flange coaxial with the circular table and the first cylindrical flange; a brushless curvilinear motor comprising an armature winding fixed in the second cylindrical flange and a rare earth magnet track fixed in said first cylindrical flange; and an encoder comprising an encoder reader mounted on the top wedge adjacent the circumference of the rotating table and an encoder scale mounted on the circumferential edge of the circular table.