Variable width apparatus for induction heating of moving workpieces

Claim 1

Induction heating apparatus comprising a pair of opposed coil assemblies between which a workpiece to be heated is moved, wherein each of said coil assemblies includes a plurality of loop windings arranged generally in a plane parallel to the plane of movement of the workpiece between said coil assemblies, said windings being arranged in groups with the windings in each of said groups being aligned transversely of the direction of movement of the workpiece, said windings of each of said groups having turned end portions that extend substantially perpendicularly to the plane of the remainder of said windings and away from the plane of movement of the workpiece, core members carrying said windings, each of said core members carrying a plurality of said windings aligned in the direction of movement of the workpiece, said core members of each of said coil assemblies being mounted for movement relative to each other in a direction transverse to the direction of movement of the workpiece to vary the spacing between said turned end portions of adjacent said windings, said adjacent turned end portions of said windings of each of said groups being separated by passive spacer members of magnetically permeable material which serve to maintain the flux pattern generated by associated said windings.