초록 ▼

A positioning table includes a pair of parallel rails defining an axis of motion. A movable assembly including a first linear motor assembly disposed for motion along one of the rails. An outboard linear motor assembly on the other rail is rigidly bridged to the first linear motor assembly for conce

A positioning table includes a pair of parallel rails defining an axis of motion. A movable assembly including a first linear motor assembly disposed for motion along one of the rails. An outboard linear motor assembly on the other rail is rigidly bridged to the first linear motor assembly for concerted motion therewith. The first linear motor assembly includes a plurality of permanent magnets defining a plane at a predetermined angle to the horizontal and an armature defining a plane at the same angle closely spaced from the permanent magnets. The permanent magnets may be disposed on the movable element of the linear motor assembly or on the first rail. The armature is disposed on the other of the movable element and the first rail. First and second bearings on the movable element of the linear motor assembly, which may be air bearings support loads in the vertical and horizontal directions. The predetermined angle establishes the direction of a magnetic attractive vector between the permanent magnets and the armature. The predetermined angle is adjusted to proportion the total load of the static and dynamic load and the magnetic attractive force to a desired value. The outboard linear motor assembly on the second rail includes a plurality of permanent magnets and a second armature. The outboard linear motor assembly and the second rail may include provision for magnetic attraction at the same predetermined angle as that employed in the first linear motor assembly.

대표청구항 ▼

A positioning device for positioning an object along at least one axis comprising: first and second rails disposed parallel to said at least one axis; at least said first rail including a horizontal top surface, a vertical side surface and a first sloping side surface; said first sloping side surfa

A positioning device for positioning an object along at least one axis comprising: first and second rails disposed parallel to said at least one axis; at least said first rail including a horizontal top surface, a vertical side surface and a first sloping side surface; said first sloping side surface making a predetermined angle with the horizontal; a first movable assembly, movable along said at least one axis; said first movable assembly including a linear motor assembly proximate to said first rail and an outboard linear motor assembly proximate to said second rail; means for rigidly connecting said linear motor assembly to said outboard linear motor assembly for concerted movement thereof; vertical bearing means for supporting vertical forces on said linear motor assembly on said horizontal top surface; horizontal bearing means for supporting horizontal forces on said linear motor assembly on said vertical side surface; a first plurality of permanent magnets defining a first plane parallel to said first sloping side surface; an armature having magnetically attractable material therein defining a second plane parallel to said first sloping side surface and closely spaced facing said first plane, whereby a first magnetic attraction exits therebetween; said first plurality of permanent magnets being disposed on one of said first sloping side surface and said first movable assembly and said armature being disposed on said other of said first sloping side surface and said first movable assembly; said second rail having a second horizontal top surface; said outboard linear motor assembly including second vertical bearing means for bearing against said second horizontal top surface; and said predetermined angle being a value effective for apportioning a total load on said vertical and horizontal bearing means in a predetermined proportion.