Actuation apparatus

Claim 1

An apparatus for positioning a workpiece, said apparatus comprising: a movable member connectable to the workpiece; energizable first electromagnetic actuating means for, when energized, producing a first force which acts on said movable member in a first direction; energizable second electromagnetic actuating means for, when energized, producing a second force which acts on said movable member in a second direction which is opposite to said first direction; said first and second forces being (i) dependent upon the position of said movable member relative to said first and second actuating means and (ii) equal when said movable member is moved to a desired position by appropriate energization of said first and second actuating means; said first and second coils being respectively associated with first and second coaxial cylindrical members which provide magnetic flux paths for said coils and which are separated by a non-magnetic spacer, said movable member being movable in a direction parallel to the axes of said first and second cylindrical members; said first and second cylindrical members forming a housing having an internal cavity and openings, said movable member being mounted in said internal cavity in said housing; mounting means for mounting the workpiece thereon; and coupling means extending through said openings in said housing and for connecting said movable member to said mounting means.

Claim 2

An apparatus for positioning a workpiece, said apparatus comprising: a movable member connectable to the workpiece; energizable first electromagnetic actuating means for, when energized, producing a first force which acts on said movable member in a first direction; energizable second electromagnetic actuating means for, when energized, producing a second force which acts on said movable member in a second direction which is opposite to said first direction; said first and second forces being (i) dependent upon the position of said movable member relative to said first and second actuating means and (ii) equal when said movable member is moved to a desired position by appropriate energization of said first and second actuating means; said first and second coils being respectively associated with first and second coaxial cylindrical members which provide magnetic flux paths for said coils and which are separated by a non-magnetic spacer, said movable member being movable in a direction parallel to the axes of said first and second cylindrical members; said first and second cylindrical members forming a housing having an internal cavity and openings, said movable member being mounted in said internal cavity in said housing; mounting means for mounting the workpiece thereon; and coupling means extending through said openings in said housing and for connecting said movable member to said mounting means.

Claim 3

An apparatus for positioning a workpiece, said apparatus comprising: a movable member connectable to the workpiece; energizable first electromagnetic actuating means for, when energized, producing a first force which acts on said movable member in a first direction; energizable second electromagnetic actuating means for, when energized, producing a second force which acts on said movable member in a second direction which is opposite said first direction; said first and second forces being (i) dependent upon the position of said movable member relative to said first and second actuating means and (ii) equal when said movable member is moved to a desired position by appropriate energization of said first and second actuating means; and a support rod, said movable member including a hollow cylinder slidably mounted on said support rod.

Claim 4

An apparatus for positioning a workpiece, said apparatus comprising: a movable member connectable to the workpiece; energizable first electromagnetic actuating means for, when energized, producing a first force which acts on said movable member in a first direction; energizable second electromagnetic actuating means for, when energized, producing a second force which acts on said movable member in a second direction which is opposite said first direction; said first and second forces being (i) dependent upon the position of said movable member relative to said first and second actuating means and (ii) equal when said movable member is moved to a desired position by appropriate energization of said first and second actuating means; and a support rod, said movable member including a hollow cylinder slidably mounted on said support rod.

Claim 5

An apparatus for positioning a workpiece, the apparatus comprising: a tubular movable member connectable to the workpiece and comprising electrically conductive material; and an energizable electromagnetic actuating device for, when energized, producing a magnetic field which induces eddy currents in the movable member, the eddy currents induced in the movable member and the magnetic field produced by the actuating device interacting to produce a force which acts on the movable member in a predetermined direction to position the workpiece.

Claim 6

An apparatus for positioning a workpiece, the apparatus comprising: a tubular movable member connectable to the workpiece and comprising electrically conductive material; and an energizable electromagnetic actuating device for, when energized, producing a magnetic field which induces eddy currents in the movable member, the eddy currents induced in the movable member and the magnetic field produced by the actuating device interacting to produce a force which acts on the movable member in a predetermined direction to position the workpiece.

Claim 9

An apparatus for positioning a workpiece, the apparatus comprising: a tubular movable member connectable to the workpiece and comprising electrically conductive material; an energizable first electromagnetic actuating device for, when energized, producing a first force which acts on the movable member in a first direction; and an energizable second electromagnetic actuating device for, when energized, producing a second force which acts on the movable member in a second direction which is opposite to the first direction; the first and second forces being (i) dependent upon the position of the movable member relative to the first and second actuating devices, and (ii) equal when the movable member is moved to a desired position by appropriate energization of the first and second actuating devices.

Claim 10

An apparatus for positioning a workpiece, the apparatus comprising: a tubular movable member connectable to the workpiece and comprising electrically conductive material; an energizable first electromagnetic actuating device for, when energized, producing a first force which acts on the movable member in a first direction; and an energizable second electromagnetic actuating device for, when energized, producing a second force which acts on the movable member in a second direction which is opposite to the first direction; the first and second forces being (i) dependent upon the position of the movable member relative to the first and second actuating devices, and (ii) equal when the movable member is moved to a desired position by appropriate energization of the first and second actuating devices.

Claim 13

An apparatus for positioning a workpiece, said apparatus comprising: a movable member connectable to the workpiece; energizable first electromagnetic actuating means for, when energized, producing a first force which acts on said movable member in a first direction; and energizable second electromagnetic actuating means for, when energized, producing a second force which acts on said movable member in a second direction which is opposite to said first direction; said first and second forces being (i) dependent upon the position of said movable member relative to said first and second actuating means, and (ii) equal when said movable member is moved to a desired position by appropriate energization of said first and second actuating means; said first and second actuating means including respective first and second coils which are connectable to respective separate AC voltage supplies, said movable member being electrically conductive, each of said first and second forces being caused by the interaction of eddy currents induced in said movable member with the magnetic field produced by the respective coil.

Claim 14

An apparatus for positioning a workpiece, said apparatus comprising: a movable member connectable to the workpiece; energizable first electromagnetic actuating means for, when energized, producing a first force which acts on said movable member in a first direction; and energizable second electromagnetic actuating means for, when energized, producing a second force which acts on said movable member in a second direction which is opposite to said first direction; said first and second forces being (i) dependent upon the position of said movable member relative to said first and second actuating means, and (ii) equal when said movable member is moved to a desired position by appropriate energization of said first and second actuating means; said first and second actuating means including respective first and second coils which are connectable to respective separate AC voltage supplies, said movable member being electrically conductive, each of said first and second forces being caused by the interaction of eddy currents induced in said movable member with the magnetic field produced by the respective coil.