An apparatus for lifting and lowering manhole covers is shown and described. The apparatus for lifting and lowering manhole covers includes a main beam secured to a vehicle connection support. A winch is secured along the main beam. The winch is configured to secure to a manhole cover. A support leg secured to the main beam such that the winch is positioned between the vehicle connection support and the support leg.

A magnetic device for magnetically coupling to a ferromagnetic body, comprises a housing having a central bore. A plurality of pole sectors arranged within an envelope of the central bore and forming a workpiece contact interface of the magnetic device, each of the plurality of pole sectors comprising a plurality of spaced-apart pole portions arranged at respective distances, wherein a recess of a plurality of recesses separates each pole portion of the plurality of pole portions, wherein a first sector forms a first pole of the magnetic device and a second sector forms a second pole of the magnetic device. A first permanent magnet. A second permanent being moveable relative to the first permanent magnet. And, an actuator operatively coupled to the at least one second permanent magnet to move the at least one second permanent magnet relative to the at least one first permanent magnet.

A magnet chuck has a piston assembly including a tube shaped permanent magnet and a core yoke able to move on the interior of a cylinder tube. The permanent magnet is provided on the outer periphery of the core yoke, is magnetized in the radial direction, and a magnetic sensor is attached to the side surface of the cylinder tube.

An apparatus for lifting and lowering manhole covers is shown and described. The apparatus for lifting and lowering manhole covers includes a main beam secured to a vehicle connection support. A winch is secured along the main beam. The winch is configured to secure to a manhole cover. A support leg secured to the main beam such that the winch is positioned between the vehicle connection support and the support leg.

An apparatus for lifting and lowering manhole covers is shown and described. The apparatus for lifting and lowering manhole covers includes a main beam secured to a vehicle connection support. A winch is secured along the main beam. The winch is configured to secure to a manhole cover. A support leg secured to the main beam such that the winch is positioned between the vehicle connection support and the support leg.

A magnetic device for magnetically coupling to a ferromagnetic body, comprises a housing having a central bore. A plurality of pole sectors arranged within an envelope of the central bore and forming a workpiece contact interface of the magnetic device, each of the plurality of pole sectors comprising a plurality of spaced-apart pole portions arranged at respective distances, wherein a recess of a plurality of recesses separates each pole portion of the plurality of pole portions, wherein a first sector forms a first pole of the magnetic device and a second sector forms a second pole of the magnetic device. A first permanent magnet. A second permanent being moveable relative to the first permanent magnet. And, an actuator operatively coupled to the at least one second permanent magnet to move the at least one second permanent magnet relative to the at least one first permanent magnet.

Magnetic coupling devices are disclosed which may be configured in at least three states. The various states may be provided through one or more of altering a position of a permanent magnet relative to another permanent magnet and altering a current level in a coil surrounding a permanent magnet.

Magnetic coupling devices are disclosed which may be configured in at least three states. The various states may be provided through one or more of altering a position of a permanent magnet relative to another permanent magnet and altering a current level in a coil surrounding a permanent magnet.

Magnetic coupling devices are disclosed which may be configured in at least three states. The various states may be provided through one or more of altering a position of a permanent magnet relative to another permanent magnet and altering a current level in a coil surrounding a permanent magnet.

Magnetic coupling devices are disclosed which may be configured in at least three states. The various states may be provided through one or more of altering a position of a permanent magnet relative to another permanent magnet and altering a current level in a coil surrounding a permanent magnet.