Door apparatus with magnetic support

A door apparatus comprising:

• (a) a door member movable between a closed position and an open position with respect to a stationary structure;
• (b) an elongated guide member mounted on one of the door member and the stationary structure, and extending along the door member to help guide movement of the door member between the open and closed positions, the elongated guide member including
• (i) an inner tube of magnetic material, and
• (ii) an outer tube of non-magnetic and electrically conductive material;
• (c) first magnet means mounted on the other of the door member and the stationary structure, to produce a propulsion magnetic force between the first magnet means and the elongated guide member to move the door member between the open and closed positions;
• and
• (d) second magnet means mounted on the other of the door member and the stationary structure, spaced from the elongated guide member, to produce a levitating magnetic force between the elongated guide member and the second magnet means to support at least part of the weight of the door member and to maintain the elongated guide member spaced from the first magnet means as the door member moves between the open and closed positions the second magnet means comprising a pair of electromagnetic units fixedly mounted on said other of the door member and the stationary structure, said electromagnetic units being spaced from each other and surrounding the elongated guide member to produce said levitating magnetic force to help support the door member and to help guide movement of the door member along the elongated guide member;
• and
• the first magnet means comprising a travelling magnetic field generating unit fixedly mounted on said other of the door member and the stationary structure between the pair of electromagnetic units.