Abstract: Disclosed is a wafer conveying system for a clean room which is high in wafer conveying efficiency, and makes it possible to achieve a variety of processing operations with high efficiency.

Abstract: A transporting apparatus using a linear motor comprises at least a primary unit and a secondary unit. The primary unit faces the secondary unit with a predetermined gap. The primary unit consists of a core and coils supplied with three-phase alternating currents so that the primary unit generates a progressive magnetic field. The secondary unit at least includes a core and permanent magnets. These permanent magnets are magnetized so that each section of the secondary unit is magnetized in a north pole and a south pole in turn along a longtitudinal direction thereof. Hence, the primary unit can be transported along the secondary unit by controlling the currents supplied to the primary unit.

Abstract: A door apparatus includes a door movable between a closed position and an open position with respect to a stationary structure, and a support device for supporting the door. The support device includes a magnet mounted on one of the door and the stationary structure, and a member of a magnetic material mounted on the other of the door and the stationary structure. The magnet and said magnetic member cooperates with each other to produce a magnetic force therebetween to support at least part of the weight of the door.

Abstract: The present invention is related to a linear motor which is composed of mainly:(a) an elongated primary magnetic member for generating a traveling magnetic field traveling along the length;(b) a secondary magnetic member for generating a stationary magnetic field, the secondary magnetic means having an elongated core, pair of permanent magnets attached to the core so as to sandwich the core from upper and lower sides, each pair being spaced constantly from each other, direction of polarity of the magnets forming a pair coinciding to each other, direction of polarity interchanging in turn from one pair to another; and(c) a support member supporting one of the primary magnetic member and the secondary magnetic member against the other so that the former is slidable along its axis against the latter.

Abstract: A door apparatus includes a door movable between a closed position and an open position with respect to a stationary structure, and a support device for supporting the door. The support device includes a magnet mounted on one of the door and the stationary structure, and a member of a magnetic material mounted on the other of the door and the stationary structure. The magnet and said magnetic member cooperates with each other to produce a magnetic force therebetween to support at least part of the weight of the door.

Abstract: An apparatus for positioning a carriage of an automatic transportation system is provided. At least a pair of magnetic cores spaced from each other in the direction of traveling of the carriage are mounted on a floor at a predetermined position within a stop zone on a track of the carriage. A yoke is mounted on a lower surface of the carriage which is disposed within a magnetic field generated by the magnetic cores when the carriage is within the stop zone. A plurality of reflection plates are mounted on the carriage and are equally spaced from one another in the direction of traveling of the carriage. A pair of reflection-type photosensors are mounted on the floor within the stop zone and output a pair of pulse trains 90.degree. out of phase from each other when the carriage moves within the stop zone. Pulses of the pulse trains are counted taking the direction of movement of the carriage into account to produce data representative of deviation of the carriage from a predetermined stop position.

Abstract: In supplying molten metal to a mold by means of an electromagnetic pump mounted on a metal container, the molten metal received in the pump is held in high temperature by means of partition walls longitudinally extending in the pump, even when the supply of molten metal is suspended for a long period. The partition walls define several passageways. In this period of suspension the driving force of travelling magnetic field is directed to the molten metal container and causes circulation of molten metal through central passageway and side passageways. Through this circulation molten metal in the pump is substantially replaced by molten metal in the container, thus making it possible to prevent solidification of molten metal in the pump by maintaining high temperature therein.