| CPC H01H 36/002 (2013.01) [B65H 3/16 (2013.01); B66C 1/04 (2013.01); H01F 7/021 (2013.01); H01F 7/0226 (2013.01); H01F 7/0242 (2013.01); H01F 7/0257 (2013.01); H01F 7/04 (2013.01)] | 16 Claims |

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1. A magnetic coupling device for magnetically coupling to a ferromagnetic workpiece positioned on a support, comprising:
a housing;
a plurality of workpiece contact interfaces supported by the housing and adapted to contact the ferromagnetic workpiece;
a magnetic flux source including
a plurality of permanent magnets supported by the housing and including a first permanent magnet and a second permanent magnet, and
a coil of wire wrapped around the second permanent magnet of the plurality of permanent magnets; and
an electronic controller operatively coupled to the coil of wire of the magnetic flux source to control a current through the coil of wire, the electronic controller including logic which results in a plurality of states of the magnetic flux source each having a respective level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the plurality of states of the magnetic flux source including:
(a) a first state wherein the magnetic flux source has a first configuration including a first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the first level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being insufficient to lift the ferromagnetic workpiece relative to the support;
(b) a second state wherein the magnetic flux source has a second configuration including a second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the second level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces being sufficient to lift the ferromagnetic workpiece relative to the support, the second level of magnetic flux being greater than the first level of magnetic flux; and
(c) a third state wherein the magnetic flux source has a third configuration including a third level of magnetic flux available to the ferromagnetic workpiece at the workpiece contact interfaces, the third level of magnetic flux being greater than each of the first level of magnetic flux and the second level of magnetic flux, wherein in the first state a north pole of the second permanent magnet is magnetically adjacent a south pole of the first permanent magnet and a south pole of the second permanent magnet is magnetically adjacent a north pole of the first permanent magnet and in both the second state and the third state the north pole of the second permanent magnet is magnetically adjacent the north pole of the first permanent magnet and the south pole of the second permanent magnet is magnetically adjacent the south pole of the first permanent magnet.
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