EP 0169564 A3 19870513 - METHOD AND APPARATUS FOR BENDING ELONGATE WORK PIECES, IN PARTICULAR TUBES
Title (en)
METHOD AND APPARATUS FOR BENDING ELONGATE WORK PIECES, IN PARTICULAR TUBES
Publication
Application
Priority
DE 3427639 A 19840726
Abstract (en)
[origin: US4596128A] 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.
IPC 1-7
IPC 8 full level
B21D 7/025 (2006.01)
CPC (source: EP US)
B21D 7/025 (2013.01 - EP US)
Citation (search report)
- [AD] FR 2392742 A1 19781229 - PRVNI BRNENSKA STROJIRNA [CS]
- [AD] FR 2181642 A1 19731207 - BABCOCK & WILCOX AG [DE]
- [AD] US 4177661 A 19791211 - KOEHLER HORST [DE], et al
- [AD] FR 2128665 A1 19721020 - COJAFEX
- [A] FR 2497696 A2 19820716 - STEIN INDUSTRIE [FR]
- [AD] DE 2738394 A1 19780316 - COJAFEX
- [AD] DE 2112019 A1 19710930 - COJAFEX
Designated contracting state (EPC)
AT BE CH DE FR GB IT LI LU NL SE
DOCDB simple family (publication)
EP 0169564 A2 19860129; EP 0169564 A3 19870513; DE 3427639 A1 19860206; DE 3427639 C2 19880414; US 4596128 A 19860624
DOCDB simple family (application)
EP 85109332 A 19850725; DE 3427639 A 19840726; US 75881185 A 19850725