Induction-heating apparatus for cold heater

Claim 1

In a cold header having a base with a front and a rear and a bore extending therethrough from rear to front, feed means located rearwardly of the base for feeding elongated metal stock forwardly through said bore, cutoff means at the front of the base in alignment with said bore for cutting off slugs from said stock, header means at the front of the base and offset from said cutoff means for heading said slugs, and holding means at the front of the base for sequentially engaging said slugs and moving them from said cutoff means to said header means; the combination with said header of an elongated induction-heating unit having a body portion disposed within said bore and a forward induction head portion with an induction coil therein located in said header adjacent said cutoff means, said heating unit including electrical conductor means connected to said coil and extending rearwardly through the heating unit and out the rear of the base for connection to an electrical source of supply, and tubular core means defining a feed passage extending longitudinally through the heating unit through which said stock is fed to said cut off means, with a forward portion of said feed passage extending coaxially through said coil for induction heating of said stock as it passes therethrough immediately before it is fed to said cutoff means, said body portion of the heating unit comprising outer and inner concentrically arranged tubular casings composed of electrically conducting material, said casings defining an annular space therebetween which is substantially filled with insulation material, said core means comprising a tube of insulation material concentrically arranged within said inner casing, and said conductor means comprising first and second electrical conductors, said first conductor extending longitudinally along the wall of said inner casing substantially within said annular space and being electrically and mechanically connected to said inner casing, and said second conductor extending longitudinally along the wall of said outer casing substantially within said annular space and being electrically and mechanically connected to said outer casing.