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US 4,596,128 AGranted
Method and apparatus for bending elongate workpieces, particularly pipes
AssigneeCojafex B.V.
InventorsJelke Ringersma, Johannes M. Hofstede
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AssigneeCojafex B.V.
InventorsJelke Ringersma, Johannes M. Hofstede
Estimating the term…
A method and apparatus for bending elongate workpieces, particularly pipes, by applying a bending moment to the workpiece while inductively heating a cross-sectional zone of the workpiece to provide a nonuniform temperature distribution along the circumference of this cross-sectional zone by means of an induction loop which surrounds the workpiece and by cooling the workpiece in at least one adjacent zone. According to the method of the invention, within a partial region of the circumference of the workpiece to be bent, which partial region is to be set at a relatively low temperature, the electrical current of the induction loop is branched off into a plurality of partial currents of which at least one is inductively directed primarily onto the cross-sectional zone to be heated and at least one other partial current is inductively directed primarily onto an adjacent zone of the workpiece, and the inductive heating of the respective adjacent zone is partially or completely cancelled out by cooling. The branching may be realized in the apparatus by a bypass line which divides a portion of the induction loop into parallel branches.
In a method of bending elongate workpieces, particularly pipes, including:
Apparatus for bending elongate workpieces, particularly pipes, comprising in combination:
Dependencies are inferred from the claim text.