A stage device usable, e.g., in an X-ray exposure apparatus, for moving a semiconductor wafer placed in a vacuum ambience and held by a wafer chuck, is disclosed. In the stage device, the wafer chuck holds the wafer so that the surface of the wafer onto which a circuit pattern is to be transferred is placed in a vertical plane, and the wafer chuck is moved vertically and horizontally for step-and-repeat exposure of the wafer. The device includes a guide mechanism, locking mechanism and a constant-tension spring mechanism, to thereby ensure high-accuracy movement of the wafer chuck in the vertical direction as well as high-precision positioning of the wafer. Further, in the stage device, a drive source producing a drive to move the wafer chuck is disposed in a vacuum ambience while, on the other hand, the supply of operating fluids to air bearing assemblies, for guiding the movement of the wafer chuck, is achieved by use of metal pipes coupled by rotary joints. The wafer chuck is resiliently supported by one of the air bearing assemblies, such that the wafer chuck can be moved in the vacuum ambience very accurately and without difficulties.

A first frame is provided, having a pair of parallel pusher bars, the inside surfaces thereof pressing against outer surfaces of a unitary workpiece support block positioned within the frame, and a second frame has a pair of pusher bars having inside surfaces pushing against the remaining outer surfaces of the unitary support block. Stationary drive means cause the independent orthogonal motion of each frame to thereby position the unitary block fitted between the overlapping frames. In a second arrangement, the unitary support block or post means is replaced by first and second pairs of post members in contact with inside surfaces of the parallel pusher bars of the first frame and in contact with outside surfaces of the parallel pusher bars of the second frame, and third and fourth pairs of post members are similarly positioned with respect to the frames. As a result, a shallow X-Y positioning system is provided enabling the direct transfer of the workpiece load through the post members to the base plate, thereby eliminating cross axis influences producing positioning inaccuracies. The overlapping relationship between the frame members also enables the X-Y motions to be very large if desired, and the second arrangement provides a central placement area for tooling.

A support structure for a signature loader or other such loading machine used in conveying of signatures for book binding comprises a fixed base having a rectangular plan form and carrying a movable support frame which is slidable along guides extending transversely of the length of the fixed base and the support frame whereby the support frame may be displaced transversely of its length so as to laterally adjust the delivery position of signatures loaded thereby. Clamping means carried by the movable support frame allow this latter to be fixed in any laterally adjusted position with respect to the fixed base once appropriate adjustments have been made to adapt the signature loader to the dimensions of signatures to be loaded at any one time.

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.

A bearing (32) for a coordinate measuring instrument including a slide (36) which can be axially displaced in relation to a fixing device (34) and which can be supported opposite the fixing device by means of at least one air bearing (38, 40). In order to be able to utilize the bearing for all axes of the coordinate measuring instrument while simultaneously using outer surfaces of the slide as mounting surfaces for sensors, the invention provides that a force that works counter to the air bearing can be generated by a magnetic field (42, 44).