Abstract: A magnetic base adapted to be secured to a magnetic substance attractively, wherein a permanent magnet 20 having a small reversible permeability .mu. is employed as a rotary magnet housed in a magnetic block 18 and rotated for switching magnetic active surfaces 24 of the block from an unexcited state to an excited state, thereby effecting a light and smooth rotation.

Abstract: The lifting device consists of an outer magnetic yoke and internal pole pieces forming an anchoring or working surface, with secondary permanent magnetic elements located between the yoke and the aforementioned pole pieces. There is also a reversible permanent magnetic element which may be rotated manually on a parallel axis to the said pole pieces, between an operative position in which its magnetic field is parallel to that of said secondary magnetic elements, and an inoperative position in which the magnetic field is short-circuited.

Abstract: A composite magnet includes at least two magnet members oriented to have their polar axes parallel and aligned, with corresponding poles facing the same direction, and two pole members made of magnetically attractive material abutting the polar surfaces of the magnets, each one abutting all the poles of a particular polarity so that one pole member forms a composite North pole and the other forms a composite South pole. A permanent magnet anchoring assembly includes a casing, made of a non-magnetically attractive material, encasing a permanent magnet member to expose at least one surface thereof. The casing is formed with at least one bearing edge located adjacent and extending parallel to and in the same plane as the exposed surface and a leverage arm extends generally perpendicular to the bearing edge for rotating the anchoring assembly about the bearing edge.

Abstract: A permanent magnet energized holding device, which has a maximum holding power for a given volume of magnetic material, can be readily switched on and off with a minimum of force. At least two pairs of plate-shaped poleplates are provided with a permanent magnet arrangement sandwiched in between. Each pair of poleplates are separated by a non-magnetic medium. The permanent magnet arrangement consists of a fixed magnet, having a circular opening, and a disc shaped magnet rotatable in the opening. The two magnets are magnetized in the direction of their smallest dimension with portions of each having opposite magnetic polarity. The portions of the stationary magnet are arranged to magnetize the pole plates with opposite magnetic polarity.

Abstract: A web treatment element in the form of a roller is attracted to one side of a web by magnetic attraction from a magnetic element positioned on the opposite side of the web. The magnetic element includes a plurality of electromagnets and a switch connected thereto to reverse the polarity of at least a portion of the electromagnets to selectively alter the polarity alignment of the electromagnets.