| 主权项 |
1. A magnetic substance holding device for holding and detaching a workpiece, the workpiece being a magnetic substance, the device comprising:
a base being a magnetic substance; a first pole piece having a holding face on which the workpiece is attached, the first pole piece being in contact with the base and being a magnetic substance; a contact pole piece having a holding face on which the workpiece is attached, the contact pole piece being spaced apart from the base and from the first pole piece and being a magnetic substance; a second pole piece being movable between a first location, at which it is spaced apart from the base and is in contact with the contact pole piece, and a second location, at which it comes in contact with the base and is spaced apart from the contact pole piece, the second pole piece being a magnetic substance; a primary permanent magnet disposed between the first pole piece and the second pole piece, one of an N-pole and an S-pole of the primary permanent magnet coming in contact with one of the first pole piece and the second pole piece while the other of the N-pole and the S-pole of the primary permanent magnet being spaced apart from the other of the first pole piece and the second pole piece; at least one coil wound around at least one of the first pole piece, the second pole piece, the base and the contact pole piece; and a control device controlling electric current applied to the coil, wherein the control device applies electric current to the coil to magnetize at least one of the first pole piece, the second pole piece, the base and the contact pole pieces to thereby control the second pole piece to be at the first location at the time of holding the workpiece so that the second pole piece comes in contact with the contact pole piece, and the second pole piece to be at the second location at the time of detaching the workpiece so that the second pole piece is spaced apart from the contact pole piece. |
