US 4,468,549 AGranted

Induction heater arrangement for forging bar stock

AssigneePark-Ohio Industries, Inc.

InventorJoseph E. Arnosky

Life of this patent

Estimating the term…

Loading patent…

Abstract

An induction heating arrangement for heating an end length of a forging bar following the cut-off therefrom of a previously heated and forged end length is arranged to heat the end length to a uniform temperature despite the existence of a residually heated terminal end from the previous heat. The heating arrangement has an induction heating coil with a longitudinally extending axial passageway therethrough for receiving the bar length to be heated by insertion into the passageway through the feed-in end thereof. A reciprocable flux diverter or robber ring is moved into the open other end of the coil passageway to surround the residually heated terminal end of the inserted bar end length, during a predetermined portion of the total coil heating cycle, to divert the flux from and prevent it from penetrating and heating the residually heated terminal end, whereby the inserted bar end length is evenly heated throughout its entire axial extent to the desired uniform forging temperature.

Claims25

Dependent claims

An induction heating apparatus for heating an end length portion of an elongated workpiece to a processing temperature during a heating cycle of said apparatus, said end length portion having a terminal end residually heated from a prior heating cycle and an axial length substantially less than said end length portion, said apparatus comprising:

an inductor having a multiturn heating coil with a linear coil axis and a workpiece-receiving passageway coaxial with said coil for accommodating the said end length portion entirely therewithin;
said passageway having an open front end at one end of said coil through which the workpiece is inserted residually heated end first, into said passageway and an open rear end at the other end of said coil, a movable flux diverter ring of high electrical conductivity, low permeability material and normally located in an inoperative position outside and adjacent the said rear end of said coil passageway, and means mounting said flux diverter ring for movement from said inoperative position into the said rear end of and axially aligned with said passageway and moving said ring to an operative position therein surrounding the said residually heated terminal end of the workpiece, during one or more portions of said heating cycle, to divert the flux generated by the energized coil away from said heated terminal end and prevent heating thereof during said heating cycle portion or portions.

Dependencies are inferred from the claim text.