US 5,744,773 AGranted

Resistance heating process and apparatus

AssigneeNewcor, Inc.

InventorsRobert G. Van Otteren, Frank Scott Mellen, Alfred R. Leger, Charles H. Gage

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Abstract

A process and apparatus for effecting preheating of elongate metal parts, such as bars, for permitting subsequent deformative processing of the bar. Electrode-type clamps are attached adjacent opposite ends of the elongate bar, and direct-current electricity is applied to the clamps for transmission longitudinally of the bar to effect heating thereof. A further pair of electrode-type clamps is applied directly at each free end of the bar, with the electrode clamps of each end pair being disposed for engagement on opposite sides of the bar substantially flush with the end face of the bar. An electric current, such as an alternating-current, is applied across the sidewardly-spaced electrode clamps of each end pair to effect transmission of electrical current transversely across the bar in the direct vicinity of the end face to effect additional heating directly at the end of the bar to supplement the heating which is effected by the direct-current passed longitudinally through the bar.

Claims21

Dependent claims

An apparatus for electrical resistance heating of a longitudinally elongate metal workpiece having peripheral side surfaces, the workpiece having a longitudinally elongate center portion joined between opposite first and second end portions each terminating in a transversely-extending end face which defines a free end of the workpiece, said apparatus comprising:

a frame;
first and second collet assemblies mounted on said frame in generally opposed but spaced relation from one another for respectively supportingly engaging respective first and second end portions of the workpiece;
first electrical resistance heating means for applying direct-current electrical energy longitudinally along said workpiece for effecting resistance heating thereof, said first heating means including first and second jaw assemblies respectively provided on said first and second collet assemblies, for engaging a surface of the respective end portion of the workpiece in the vicinity of the respective end face, said first and second jaw assemblies respectively including first and second jaws each comprising an electrode for transmitting electrical current therethrough;
said first heating means also including a first direct-current electrical power source connected to said first and second jaw assemblies so as to define a conductive path longitudinally along said workpiece to effect resistance heating thereof due to passage of direct-current electrical energy longitudinally therethrough;
second electrical resistance heating means for transmitting electrical energy transversely across said first end portion of said workpiece in close proximity to the respective end face for effecting electrical resistance heating thereof, said second resistance heating means including third and fourth jaw assemblies both associated with said first collet assembly for clampingly engaging opposite peripheral side surfaces of said first end portion of said workpiece in directly adjacent relation to the respective end face, said third and fourth jaw assemblies respectively defining third and fourth jaws which are disposed in generally opposed relationship and cooperate as a pair for clampingly engaging opposed peripheral side surfaces of said first end portion of said workpiece therebetween, each of said third and fourth jaws comprising an electrode for transmitting electrical energy therethrough;
and
said second resistance heating means also including a second electrical power source connected to said third and fourth jaws for permitting electrical energy to be transmitted directly between said third and fourth jaws so as to be transmitted transversely across said first end portion of said workpiece in close relation with the respective end face to effect electrical resistance heating of said first end portion.

4 more elements

a frame;
first and second collet assemblies mounted on said frame in generally opposed but spaced relation from one another for respectively supportingly engaging respective first and second end portions of the workpiece;
first electrical resistance heating means for applying direct-current electrical energy longitudinally along said workpiece for effecting resistance heating thereof, said first heating means including first and second jaw assemblies respectively provided on said first and second collet assemblies, for engaging a surface of the respective end portion of the workpiece in the vicinity of the respective end face, said first and second jaw assemblies respectively including first and second jaws each comprising an electrode for transmitting electrical current therethrough;
said first heating means also including a first electrical power source connected to said first and second law assemblies so as to define a conductive path longitudinally along said workpiece to effect resistance heating thereof due to passage of electrical energy longitudinally therethrough;
second electrical resistance heating means for transmitting electrical energy transversely across said first end portion of said workpiece in close proximity to the respective end face for effecting electrical resistance heating thereof, said second resistance heating means including third and fourth law assemblies both associated with said first collet assembly for clampingly engaging opposite peripheral side surfaces of said first end portion of said workpiece in directly adjacent relation to the respective end face, said third and fourth jaw assemblies respectively defining third and fourth jaws which are disposed in generally opposed relationship and cooperate as a pair for clampingly engaging opposed peripheral side surfaces of said first end portion of said workpiece therebetween, each of said third and fourth jaws comprising an electrode for transmitting electrical energy therethrough;
and
said second resistance heating means also including a second electrical power source connected to said third and fourth jaws for permitting electrical energy to be transmitted directly between said third and fourth laws so as to be transmitted transversely across said first end portion of said workpiece in close relation with the respective end face to effect electrical resistance heating of said first end portion;
each of said first to fourth jaw assemblies comprising an elongate platelike clamping member constructed of an electrically conductive material, said elongate clamping member being fixedly mounted adjacent one end thereof and being cantilevered outwardly therefrom and having the respective jaw fixedly mounted adjacent the other end thereof, said jaw being provided on a side face of said clamping member adjacent said other end, said clamping member being resiliently deflectable, and an activating device for effecting resilient deflection of each said clamping member to effect movement of the respective jaw into clamping engagement with the workpiece.

5 more elements

A process for effecting electrical resistance heating of a longitudinally elongate rodlike metal workpiece, comprising the steps of:

providing a longitudinally elongate rodlike metal workpiece having a longitudinally elongate center portion joined between first and second end portions each terminating in an end face which defines a free end of the workpiece, the end portions having first and second pairs of generally parallel and opposite peripheral side surfaces;
attaching first and second electrodes to the respective first and second end portions of said workpiece;
transmitting direct-current electrical energy longitudinally along said workpiece from one of said first and second electrodes to the other of said first and second electrodes to effect resistance heating of the bar by applying direct-current electrical energy to said first and second electrodes;
attaching third and fourth electrodes to diametrically opposite side surfaces of said first end portion in directly adjacent relationship to the respective end face;
and
transmitting electrical energy transversely across said first end portion between said third and fourth electrodes to effect resistance heating of said first end portion by applying electrical energy to said third and fourth electrodes simultaneous with the application of electrical energy to said first and second electrodes.

3 more elements

a frame;
support means mounted on said frame for respectively supportingly engaging said first and second end portions of said workpiece;
electrical resistance heating means for applying electrical energy through said workpiece for effecting resistance heating thereof, said heating means including first and second jaw assemblies provided on said support means for engaging respective spaced apart first and second surface sections of the peripheral side surfaces of said workpiece, said first and second jaw assemblies respectively including first and second jaws each comprising an electrode for transmitting electrical current therethrough;
said heating means also including an electrical power source connected to said first and second jaw assemblies so as to define a conductive path between said first and second surface sections through said workpiece to effect resistance heating thereof due to passage of said electrical energy therethrough;
and
at least one of said first and second jaw assemblies comprising an elongate plate-like clamping member constructed of an electrically conductive material, said elongate clamping member being fixedly mounted adjacent one end thereof and being cantilevered outwardly therefrom and having the respective jaw fixedly mounted adjacent the other end thereof, said respective jaw being provided on a side face of said clamping member adjacent said other end, said clamping member being resiliently deflectable, and an activating device for effecting resilient deflection of said clamping member to effect movement of the respective jaw into clamping engagement with the respective surface section of the workpiece.

3 more elements

Dependencies are inferred from the claim text.