Electromagnetic devices

Claim 2

An electromagnetic device comprising a pair of relatively movable magnetisable members and an electrical winding means through which can be passed an electric current to produce a magnetic field to effect relative movement of the members, in which one of said members defines a plurality of slots disposed in side by side relationship on one face of the said one member, the other said member defining a plurality of projections entering into the said slots respectively and of a smaller width than the slots, at least some of said slots accommodating said electrical winding means, the connection of the winding means being such that any two slots in which the flow of current in the winding means therein is in the same direction are separated by a slot with a winding means in which the flow of current is in the opposite direction, the arrangement being such that if said members are positioned so that said projections are not centrally disposed in said slots, the members will, upon current being passed through said winding means, be urged relative to each other in an attempt to reduce the size of the smaller gap between each projection and the side faces of the associated slot.

Claim 3

An electromagnetic device comprising a pair of relatively movable magnetisable members and an electrical winding means through which can be passed an electric current to produce a magnetic field to effect relative movement of the members, in which one of said members defines a plurality of slots disposed in side by side relationship on one face of the said one member, the other said member defining a plurality of projections entering into the said slots respectively, said projections being of a smaller depth and width than said slots, each of said slots accommodating said electrical winding means, the connection of the winding means being such that the flow of electric current in the winding means in one slot will be in one direction only, and the flow of current in the winding means in an adjacent slot will be in the opposite direction, the arrangement being such that if said members are positioned so that said projections are not centrally disposed in said slots, the members will, upon current being passed through said winding means, be urged relative to each other in an attempt to reduce the size of the smaller gap between the projections and the side faces of the slots.

Claim 4

An electromagnetic device comprising a pair of relatively movable magnetisable members and an electrical winding means through which can be passed an electric current to produce a magnetic field to effect relative movement of the members, in which one of said members defines a plurality of slots disposed in side by side relationship on one face of the said one member, the other said member defining a plurality of projections entering into the said slots respectively, said projections being of a smaller depth and width than said slots, each of said slots accommodating said electrical winding means, the connection of the winding means being such that the flow of electric current in the winding means in one slot will be in one direction only, and the flow of current in the winding means in an adjacent slot will be in the opposite direction, the arrangement being such that if said members are positioned so that said projections are not centrally disposed in said slots, the members will, upon current being passed through said winding means, be urged relative to each other in an attempt to reduce the size of the smaller gap between the projections and the side faces of the slots.

Claim 5

A device according to claim 2 in which the depth and shape of said slots is such in relation to the size of said projections as to provide accommodation for said winding means.

Claim 6

A device according to claim 2 in which one of said pair of members is of cylindrical form and the other of said pair of members is of annular form, said slots and projections being defined by screw threads formed on the presented surfaces of said pair of members.

Claim 7

A device according to claim 4 in which the screw thread is an even start thread.

Claim 8

A device according to claim 5 in which said winding means comprises a single length of wire.

Claim 9

A device according to claim 6 in which said wire is wound in one groove towards one end of the member and returns in an adjacent groove towards the other end of the member.

Claim 10

A device according to claim 7 in which said wire passes through an aperture formed in the member in which the grooves are formed.

Claim 11

A device as claimed in claim 7 in which a plurality of turns are provided in each groove.

Claim 12

A device as claimed in claim 5 in which each groove is provided with a pair of windings, one of which can be energised to partly magnetize the members, and the other of which can be energised to magnetize the members a further amount to cause relative movement of the members.

Claim 13

A device according to claim 4 in which said other of said pair of members is thinly formed on its outer periphery to reduce the thickness of material and thereby reduce the inertia of the member.

Claim 14

A device according to claim 4 in which said other of said pair of members is provided with projections on its outer peripheral surface and a third annular member is provided surrounding said other of said pair of members, said third annular member having helical slots machined on its internal periphery in registry with the projections on the outer surface of said other of said pair of members, said one of said pair of members and said third member each mounting windings.

Claim 15

A device as claimed in claim 12 in which the windings on said one of said pair of members and on said third member, when energised, effect movement of said other of said pair of members in the same direction.

Claim 16

A device as claimed in claim 12 in which the windings on said one of said pair of members and on said third member, when energised, effect movement of said other of said pair of members in opposite directions respectively.

Claim 17

The combination of a pair of devices as claimed in claim 5 in which the respective devices are coupled together so that energisation of the electrical windings of one of the devices will result in relative axial movement of the devices in one direction and energisation of the windings of the other of the devices will result in relative axial movement of the devices in the opposite direction.

Claim 18

The combination of a pair of devices as claimed in claim 5 in which the respective devices are coupled together, the helix angles of the projections and grooves of one of the devices being opposite to those of the other device so that the turning force generated between the members of each device when the windings are energised is cancelled.

Claim 19

An electromagnetic device comprising a pair of relatively movable magnetisable members and an electrical winding means through which can be passed an electric current to produce a magnetic field to effect relative movement of the members, in which one of said members defines a plurality of slots disposed in side by side relationship on one face of the said one member, the other said member defining a plurality of projections entering into the said slots respectively and of a smaller width than the slots, said winding means including windings in a pair of adjacent slots, the connection of the windings being such that the flow of current in the windings in the pair of adjacent slots is in the opposite direction, the arrangement being such that if said members are positioned so that said projections are not centrally disposed in said slots, the members will, upon current being passed through said windings, be urged relative to each other in an attempt to reduce the size of the smaller gap between each projection and the side faces of the associated slot.

Claim 20

An electromagnetic device comprising a pair of relatively movable magnetisable members and an electrical winding means through which can be passed an electric current to produce a magnetic field to effect relative movement of the members, in which one of said members defines a plurality of slots disposed in side by side relationship on one face of the said one member, the other said member defining a plurality of projections entering into the said slots respectively and of a smaller width than the slots, said winding means including windings in a pair of adjacent slots, the connection of the windings being such that the flow of current in the windings in the pair of adjacent slots is in the opposite direction, the arrangement being such that if said members are positioned so that said projections are not centrally disposed in said slots, the members will, upon current being passed through said windings, be urged relative to each other in an attempt to reduce the size of the smaller gap between each projection and the side faces of the associated slot.

Claim 21

A device according to claim 17 in which the depth and shape of the slots is such in relation to the size of the projections as to provide accommodation for the windings.