US3737618A - Method and apparatus for resistance heating slotted tubes - Google Patents
Method and apparatus for resistance heating slotted tubes Download PDFInfo
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- US3737618A US3737618A US00177932A US3737618DA US3737618A US 3737618 A US3737618 A US 3737618A US 00177932 A US00177932 A US 00177932A US 3737618D A US3737618D A US 3737618DA US 3737618 A US3737618 A US 3737618A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/40—Direct resistance heating
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- ABSTRACT A method and apparatus for resistance heating an elongated tube having a slot-like area therein extending generally longitudinally over a portion of the length, which tube is to be subsequently formed at the slot area following heating.
- the tube is clamped between first and second pairs of contacts spaced immediately adjacent each end thereof.
- Third and fourth pairs of contacts are then clamped over the tube adjacent each end of the slot-like area and between the first and second pairs of contacts.
- An electrical current is then caused to flow through the tube between the first and third and the second and fourth pairsof contacts to effect heating of the tube ends.
- the third and fourth pairs of contacts are then removed from contact with the tube and an electrical current is caused to flow through the tube between the first and second pairs of contacts to effect desired heating over the entire length of tube.
- the invention is particularly applicable to resistance heating slotted tubes which are to be formed at least at the slot area following heating and will be described with particular reference thereto; however, it will be appreciated that the invention has broader applications and may be employed in any instance where elongated workpieces having at least one aperture therein are de-:
- Previous apparatus and methods for resistance heating elongated slotted workpieces have generally comprised placing the tube between first and second pairs of spaced apart heating contacts so that the tube was held therebetween at substantially the end points thereof. An electrical current was then caused to flow through the tube between these pairs of heating contacts in order that the desired resistance heating would be effected.
- certain inherent drawbacks were present making it virtually impossible to obtain uniform heating over the entire tube length: This, of course, was primarily due to the presence of an elongated slot-like area in the tube itself.
- resistance heating there is an actual current flow through a workpiece being heated and, as current generally seeks the path of least resistance, the tube is heated to substantially higher temperatures along the sides of the slotted areas than at the ends of these areas and the ends of the tube itself. This,
- the present invention contemplates a new method and apparatus which overcome the above referred problems and provides a new method and apparatus for heating elongated slotted tubes which is economical to employ, provides uniform heating over substantially the entire tube length and is readily adaptable to use with other elongated workpieces having slotted or other recess areas therein.
- a method of heating an elongated workpiece having first and second terminal end portions and an intermediate portion having an intermediate portion having an aperture therein comprising a. clamping the workpiece between first and .second pairs of contacts at first and second spaced positions along the workpieces;
- the method of resistance heating further includes the steps of removing the third and fourth pairs of contacts from the clamping positions when those portions of the slotted tube disposed between the first and third pairs of contacts and the second and fourth pairs of contacts have been heated to a predetermined desired temperature; and, causing an electrical current to flow through the workpiece between the first and second pairs of contacts to heat the tube to a predetermined desired temperature over the entire length thereof.
- an apparatus for heating an elongated workpiece having at least one slot-like area extending longitudinally therealong.
- the apparatus in cludes first and second spaced apart pairs of contacts having a first opened condition and a second workpiece clamping and heating conditionatfirst and second positions adjacent the ends of the workpiece and first means for forcing the first and second pairsof contacts between the first and second conditions.
- Third and fourth pairs of contacts are spaced between the first and second pairs of contacts and from each other. These pairs of contacts have a third opened condition and a fourth workpiece clamping and heating condition and further include means for forcing them between the third and fourth conditions.
- Means areincluded for supplying electrical current to the first and third pairs of contacts when thefirst pair of contacts is in the second condition and the third pair of contacts is in the fourth condition and to the second and fourth pairs of contacts when the second pair of contacts is in the second condition and the fourth pair of contacts is in the fourth condition.
- the apparatus includes means for supplying electrical current to the first and second pairs of contacts when theyare in the second condition and the third and fourth pairs of contacts are in the third condition.
- the principal object of the present invention is the provision of a method and apparatus for resistance heating an elongated slotted workpiece which provides uniform heating over the entire workpiece length.
- Another object of the present invention is the provision of a method and apparatus for resistance heating an elongated slotted workpiece which is simple and economical to use. 5
- FIG. 2 is a cross sectional view taken along lines 2--2' in FIG. 1 showing in particular the type of heating contacts utilized.
- FIG. 3 is a front view showing the first heating stage of the subject new method and apparatus for resistance heating.
- FIG. 4 is a front view showing the second stage of the subject new method and apparatus for resistance heatmg.
- FIGURES show an elongated slotted tube A clamped in a heating positionbetween pairs of heating contacts of resistance heating apparatus B.
- FIGS. 1 and 2 show the prior art apparatus hereinbefore used where there is shown a length of steel tubing having ends 12, 14.
- tubing 10 is of a thin wall type (FIG. 2), although other types of tubing or elongated workpieces have been heated by this type of apparatus.
- Disposed in tubing 10 and extending transversely therethrough is an elongated slot or aperture generally desig-' nated 18 and having parallel side wall portions 20,22 and opposed radiused end portions 24,26 which interconnect the side wall portions.
- This type of slotted tube is used for a variety of purposes in the industrial environment such as, for example, as the outer sleeve for providing an adjustment device.
- FIG. 1 a pair of contact-arm assemblies generally designated 30,32 are shown in clamping engagement with the tube adjacent ends 12,14 respectively.
- Contact arm assembly 30 includes a pair of opposed contact areas 34,36 and contact arm assembly 32 includes a pair of similarly opposed contact areas 38,40.
- FIG. 2 shows contact arm assembly 30 in more detail, it being understood that contact arm 32 is identical therewith except where otherwise specifically noted..
- Contact assemblies 34,36 include copper contact blocks 35,37 respectively which include V-shaped workpiece receiving grooves 42,43 therein which is known in the art.
- Contact assembly 34 is affixed to a contact arm 50 and contact assembly 36 is affixed to a contact arm 52, arms 50,52 being pivotally mounted relative to each other at pivot area 54.
- the result of this arrangement is to provide a scissors-like structure with the contact areas disposed at one end and a fluid power cylinder 56 disposed at the other and mounted to each of the contact arms by convenient means such as standard clevis mountings.
- contact areas 34,36 are moved toward each other to engage a workpiece in grooves 42,43 of contact blocks 35,37.
- a current supply generator generally designated 60 is provided to selectively supply current to contact blocks 35,37.
- the current supply source is also attached to the contact blocks of contact areas 38,40 to effect a current flow between assemblies 30,32 through tube 10.
- contact arm assemblies 30,32 are positioned away from each other in order that they will engage the tube substantially adjacent ends 12,14 as it has been found and is known that the most efficient resistance heating occurs throughout the workpiece when so positioned.
- the contact areas 34,36 and 38,40 in a first or spaced apart condition, the workpiece is positioned between them and cylinders 56 energized to extend so that contact assemblies are moved to a second or clamping and heating condition. Thereafter electrical current is caused to flow through the workpiece to effect the heating.
- the current flow lines through tube 10 in FIG. 1 are along lines a as shown therein.
- the areas of the tube extending coextensive with side walls 20,22 of slot 18 receive the bulk of the cur rent flow and therefore heated to a far greater degree than that portion of tube 10 adjacent end wall portions 24,26 of the slot and ends 12,14 of the tube itself.
- a third contact arm assembly generally designated is disposed adjacent assembly 30 and a fourth contact arm assembly 72 is disposed adjacent assembly 32.
- Assembly 70 includes a pair of opposed contact areas 74,76 and assembly 72 includes a pair of opposed contact areas 78,80. These contact areas are similar to the previously hereinabove described contact areas.
- contact arm assemblies 70,72 include power means (not shown) for moving the contact areas between a third spaced apart condition and a fourth clamping condition in contact with the tube as also has been hereinabove described.
- assemblies 30,32 are trans versely spaced apart from each other so that their respective contact areas will engage tube 10 immediately adjacent ends 12,14. Further, assemblies 70,72 are spaced inboard of assemblies 30,32 and transversely spaced apart from each other so that when their respective contact areas are moved to the fourth condition,
- Means known in the art and generally designated 90,92 are provided to establish electrical current flow through the tube between the contact areas of assemblies 30,70 and between the contact areas of assemblies 32,72 respectively.
- electrical supply means 90,92 When the tube is in position, clamped between contact areas of the contact arm assemblies 30,70 and 32,72 and electrical supply means 90,92 are energized, the ends of the tube, outboard of and including end wall portions 24,26 are heated as shown by the schematic current flow lines generally designated b.
- electrical supply means 90,92 are deenergized and the contact areas of assemblies 70,72 are moved to the third or spaced apart condition. -'This movement is best shown in FIG. 4.
- an electrical current supply means generally designated 94 interconnected between assemblies 30,32 is energized so as to provide current flow through tube between them as hereinabove previously described with reference to the Prior art.
- the lines of current flow are schematically shown in FIG. 4 by lines c.
- the principal portion of the tube heated is that section extending along side wall portions 20,22 which was previously unheated and a portion of the tube between end 12 and end portions 24 and. end portions and end 14 and end portion 26 which had previously .been heated to a temperature of approximately 2, O00F. As the end portions are also receiving some heating, they will not cool substantially while the initially unheated portion is being heated to bring the tube to the final desired temperature.
- the contact areas of contact arm assemblies 30,32 may be moved from the second heating condition shown in FIG. 4 to the first openedcondition and the tube removed therefrom, another unheated tube inserted and the process repeated as desired.
- the heated tube may then be moved for further processing and forming as desired.
- step of clamping said workpiece at first and second spaced positions comprises the step of clamping said workpiece adjacent the ends thereof.
- step of resistance heating substantially the entire workpiece comprises the steps or removing said third and said fourth contacts from electrical contact against said intermediate portion and causing an electrical current to flow through said workpiece between said first and said second contacts.
- An apparatus for resistance heating an elongated workpiece having at least one slot-like area extending longitudinally therealong comprising:
- first and second spaced apart pairs of contacts each pair having a first opened condition and a second workpiece clamping and heating condition wherein when said firstand second pairs of contacts arein said second condition, said first pair of contacts engages said wOrkpiece adjacent one end thereof and said second pair of contacts engages said workpiece adjacent the other end thereof;
- first means for selectively forcing said first and second pairs of contacts between said first and second conditions
- each of said third and fourth pairs of contacts spaced between said first and second pairs of contacts respectively and from each other, each of said third and fourth pairs of contacts having a third opened condition and a fourth workpiece clamping-and heatingco'ndition wherein when said third and fourth'contacts are in said fourth condition, said thirdpair of con first means for supplying electrical current to saidfirst and third pairs of contactswhen' said first pair of contacts is in said second condition and said third pair of contacts is in said fourthcondition; and, 4 second means for supplying electrical current to said" second and fourth pairs of contacts when said-second pair of contacts is in said second condition and said fourth pair of contacts is in said fourth condition.
- the apparatus as defined in claim 7 further including third means for supplying electrical current to said first and second pairs of contacts when said first and second pairs of contacts are in said second condition and said third and fourth pairs of contacts are in said third condition.
- first, second and third supplying means comprise a single supplying means selectively controllable for supplying electrical current to said first and third, said second and fourth and said first and second pairs of contacts.
- an apparatus for resistance heating an elongated workpiece having first and second terminal end portions and an intermediate portion having an aperture with'two longitudinally spaced terminal areas, one terminal area facing said first end portion and the other terminal area facing said second end portion, said apparatus including first and second spaced contacts, first means for selectively forcing said first and second contacts between a spaced apart condition and an electrical contacting condition with said workpiece at said first and second terminal end portions respectively and first means for causing electrical current flow through said workpiece between said first and second contacts, the improvement comprising:
- a third contact including second means for selectively forcing said third contact between a spaced apart condition and an electrical contacting conditiOn with said workpiece at said one terminal area;
- a fourth contact including third means forselectively forcing said fourth contact between a spaced apart condition and an electrical contacting condition with said workpiece at said other terminal area;
- said third and fourth contacts each comprise a pair of contacts, at least one contact in each of said pairs being selectively movable relative to the other contact in said pairs between said spaced apart conditions and ,said
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Abstract
A method and apparatus for resistance heating an elongated tube having a slot-like area therein extending generally longitudinally over a portion of the length, which tube is to be subsequently formed at the slot area following heating. The tube is clamped between first and second pairs of contacts spaced immediately adjacent each end thereof. Third and fourth pairs of contacts are then clamped over the tube adjacent each end of the slot-like area and between the first and second pairs of contacts. An electrical current is then caused to flow through the tube between the first and third and the second and fourth pairs of contacts to effect heating of the tube ends. The third and fourth pairs of contacts are then removed from contact with the tube and an electrical current is caused to flow through the tube between the first and second pairs of contacts to effect desired heating over the entire length of tube.
Description
United States Patent 1 Arnosky METHOD AND APPARATUS FOR RESISTANCE HEATING SLOTTED TUBES lnventorz- Joseph E. Arnosky, Broadview Heights, Ohio 44147 Park-Ohio Industries Inc., Cleveland,0hio
Filed: Sept. 7, 1971 Appl. No.1 177,932
Assignee:
US. Cl. ..2l9/l56, 219/56, 219/58, 219/59, 219/67 Int. Cl. ..C21d 9/62 Field of Search ..219/156, 59, 64,
References Cited UNITED STATES PATENTS June 5, 1973 [57] ABSTRACT A method and apparatus for resistance heating an elongated tube having a slot-like area therein extending generally longitudinally over a portion of the length, which tube is to be subsequently formed at the slot area following heating. The tube is clamped between first and second pairs of contacts spaced immediately adjacent each end thereof. Third and fourth pairs of contacts are then clamped over the tube adjacent each end of the slot-like area and between the first and second pairs of contacts. An electrical current is then caused to flow through the tube between the first and third and the second and fourth pairsof contacts to effect heating of the tube ends. The third and fourth pairs of contacts are then removed from contact with the tube and an electrical current is caused to flow through the tube between the first and second pairs of contacts to effect desired heating over the entire length of tube.
11 Claims, 4 Drawing Figures PATENTEUJJH 5% 3,737. 618
INVENTOR. JQSEPH E. ARNOSKY 2% vfigy AT TOR NEYS.
METHOD AND APPARATUS FOR RESISTANCE HEATING SLOTTED TUBES This application pertains to the art of resistance heating and more particularly to a method and apparatus for resistance heating an elongated slotted workpiece.
The invention is particularly applicable to resistance heating slotted tubes which are to be formed at least at the slot area following heating and will be described with particular reference thereto; however, it will be appreciated that the invention has broader applications and may be employed in any instance where elongated workpieces having at least one aperture therein are de-:
sired to be uniformly heated over the entire length thereof.
Previous apparatus and methods for resistance heating elongated slotted workpieces have generally comprised placing the tube between first and second pairs of spaced apart heating contacts so that the tube was held therebetween at substantially the end points thereof. An electrical current was then caused to flow through the tube between these pairs of heating contacts in order that the desired resistance heating would be effected. However, in using this approach for elongated slotted tubes, certain inherent drawbacks were present making it virtually impossible to obtain uniform heating over the entire tube length: This, of course, was primarily due to the presence of an elongated slot-like area in the tube itself. In resistance heating, there is an actual current flow through a workpiece being heated and, as current generally seeks the path of least resistance, the tube is heated to substantially higher temperatures along the sides of the slotted areas than at the ends of these areas and the ends of the tube itself. This,
of course, is because there is less tube area to be heated along the sides of the slots so that the current flow is concentrated at that area to thereby cause a faster heating rate. The result has been ineffective and nonuniform heating which left cold spots along certain areas of the tubes. These cold spots oftentimes created difficulties when the forming step was attempted such that undesirable scrap workpieces were generated. v
The present invention contemplates a new method and apparatus which overcome the above referred problems and provides a new method and apparatus for heating elongated slotted tubes which is economical to employ, provides uniform heating over substantially the entire tube length and is readily adaptable to use with other elongated workpieces having slotted or other recess areas therein.
In accordance with. one aspect of the present invention, there is provided a method of heating an elongated workpiece having first and second terminal end portions and an intermediate portion having an intermediate portion having an aperture therein comprising a. clamping the workpiece between first and .second pairs of contacts at first and second spaced positions along the workpieces;
b. clamping the workpiece between third and fourth pairs of contacts at third and fourth spaced positions between the first and second positions respectively with the third and fourth positions each being disposed adjacent an end of the slot-like area; and, y I
c. causing an electrical current to flow through the workpiece between the first and third pairs of contacts and through the workpiece between the second and fourth pairs of contacts.
In accordance with a more limited aspect of the present invention, the method of resistance heating further includes the steps of removing the third and fourth pairs of contacts from the clamping positions when those portions of the slotted tube disposed between the first and third pairs of contacts and the second and fourth pairs of contacts have been heated to a predetermined desired temperature; and, causing an electrical current to flow through the workpiece between the first and second pairs of contacts to heat the tube to a predetermined desired temperature over the entire length thereof.
In accordance with another aspect of the present invention, there is provided an apparatus for heating an elongated workpiece having at least one slot-like area extending longitudinally therealong. The apparatus in cludes first and second spaced apart pairs of contacts having a first opened condition and a second workpiece clamping and heating conditionatfirst and second positions adjacent the ends of the workpiece and first means for forcing the first and second pairsof contacts between the first and second conditions. Third and fourth pairs of contacts are spaced between the first and second pairs of contacts and from each other. These pairs of contacts have a third opened condition and a fourth workpiece clamping and heating condition and further include means for forcing them between the third and fourth conditions. Means areincluded for supplying electrical current to the first and third pairs of contacts when thefirst pair of contacts is in the second condition and the third pair of contacts is in the fourth condition and to the second and fourth pairs of contacts when the second pair of contacts is in the second condition and the fourth pair of contacts is in the fourth condition.
In accordance with a more limited aspect of the present invention, the apparatus includes means for supplying electrical current to the first and second pairs of contacts when theyare in the second condition and the third and fourth pairs of contacts are in the third condition.
The principal object of the present invention is the provision of a method and apparatus for resistance heating an elongated slotted workpiece which provides uniform heating over the entire workpiece length.
Another object of the present invention is the provision of a method and apparatus for resistance heating an elongated slotted workpiece which is simple and economical to use. 5
Another object of the present invention is the provision of a method and apparatus for resistanceheating an elongated slotted workpiece which method and apparatus are readily adaptable for use with elongated workpieces having any cross sectional configuration l FIG. 2 is a cross sectional view taken along lines 2--2' in FIG. 1 showing in particular the type of heating contacts utilized.
FIG. 3 is a front view showing the first heating stage of the subject new method and apparatus for resistance heating; and,
FIG. 4 is a front view showing the second stage of the subject new method and apparatus for resistance heatmg.
Referring now to the drawings wherein the showings are for the purposes of illustrating the preferred embodiment of the invention only and not for purposes of limiting same, the FIGURES show an elongated slotted tube A clamped in a heating positionbetween pairs of heating contacts of resistance heating apparatus B.
More specifically, FIGS. 1 and 2 show the prior art apparatus hereinbefore used where there is shown a length of steel tubing having ends 12, 14. In the preferred embodiment, tubing 10 is of a thin wall type (FIG. 2), although other types of tubing or elongated workpieces have been heated by this type of apparatus. Disposed in tubing 10 and extending transversely therethrough is an elongated slot or aperture generally desig-' nated 18 and having parallel side wall portions 20,22 and opposed radiused end portions 24,26 which interconnect the side wall portions. This type of slotted tube is used for a variety of purposes in the industrial environment such as, for example, as the outer sleeve for providing an adjustment device. Most often, a slotted area is machines in tubing 10 and the tubing then heat treated. In FIG. 1, a pair of contact-arm assemblies generally designated 30,32 are shown in clamping engagement with the tube adjacent ends 12,14 respectively. Contact arm assembly 30 includes a pair of opposed contact areas 34,36 and contact arm assembly 32 includes a pair of similarly opposed contact areas 38,40. FIG. 2 shows contact arm assembly 30 in more detail, it being understood that contact arm 32 is identical therewith except where otherwise specifically noted..
In using the above described prior apparatus, contact arm assemblies 30,32 are positioned away from each other in order that they will engage the tube substantially adjacent ends 12,14 as it has been found and is known that the most efficient resistance heating occurs throughout the workpiece when so positioned. With the contact areas 34,36 and 38,40 in a first or spaced apart condition, the workpiece is positioned between them and cylinders 56 energized to extend so that contact assemblies are moved to a second or clamping and heating condition. Thereafter electrical current is caused to flow through the workpiece to effect the heating. However, as current flow through any conductor has the tendency to flow through the path of least resistance, the current flow lines through tube 10 in FIG. 1 are along lines a as shown therein. As can be seen, the areas of the tube extending coextensive with side walls 20,22 of slot 18 receive the bulk of the cur rent flow and therefore heated to a far greater degree than that portion of tube 10 adjacent end wall portions 24,26 of the slot and ends 12,14 of the tube itself. a
To overcome these prior difficulties, the subject invention provides the method and apparatus which will hereinafter be described with reference to FIGS. 3 and 4. Like components will be described with like numerals and new or additional components will be described with new numerals. With reference to FIG. 3, and in accordance with the present invention, a third contact arm assembly generally designated is disposed adjacent assembly 30 and a fourth contact arm assembly 72 is disposed adjacent assembly 32. Assembly 70 includes a pair of opposed contact areas 74,76 and assembly 72 includes a pair of opposed contact areas 78,80. These contact areas are similar to the previously hereinabove described contact areas. Further, contact arm assemblies 70,72 include power means (not shown) for moving the contact areas between a third spaced apart condition and a fourth clamping condition in contact with the tube as also has been hereinabove described.
In utilizing this structure, assemblies 30,32 are trans versely spaced apart from each other so that their respective contact areas will engage tube 10 immediately adjacent ends 12,14. Further, assemblies 70,72 are spaced inboard of assemblies 30,32 and transversely spaced apart from each other so that when their respective contact areas are moved to the fourth condition,
they will engage the tube immediately adjacent end wall portions 24,26. Means known in the art and generally designated 90,92 are provided to establish electrical current flow through the tube between the contact areas of assemblies 30,70 and between the contact areas of assemblies 32,72 respectively. When the tube is in position, clamped between contact areas of the contact arm assemblies 30,70 and 32,72 and electrical supply means 90,92 are energized, the ends of the tube, outboard of and including end wall portions 24,26 are heated as shown by the schematic current flow lines generally designated b. In the preferred embodiment, when the temperature of those portions of the tube being heated have reached a temperature of approximately 2,000F., electrical supply means 90,92 are deenergized and the contact areas of assemblies 70,72 are moved to the third or spaced apart condition. -'This movement is best shown in FIG. 4.
Once the contact areas of assemblies 70,72 have been moved to the third condition, an electrical current supply means generally designated 94 interconnected between assemblies 30,32 is energized so as to provide current flow through tube between them as hereinabove previously described with reference to the Prior art. The lines of current flow are schematically shown in FIG. 4 by lines c. Because of the current flow, the principal portion of the tube heated is that section extending along side wall portions 20,22 which was previously unheated and a portion of the tube between end 12 and end portions 24 and. end portions and end 14 and end portion 26 which had previously .been heated to a temperature of approximately 2, O00F. As the end portions are also receiving some heating, they will not cool substantially while the initially unheated portion is being heated to bring the tube to the final desired temperature. Once the desired temperature is obtained, the contact areas of contact arm assemblies 30,32 may be moved from the second heating condition shown in FIG. 4 to the first openedcondition and the tube removed therefrom, another unheated tube inserted and the process repeated as desired. The heated tube may then be moved for further processing and forming as desired.
The invention has been described with reference to the preferred embodiment. Obviously, modifications and alterations will occur to others upon the reading and understanding of this specification. It is my intention to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Having thus described my invention, I now claim: 1. A method of resistance heating an elongated work piece having at least one slot-like area extending generally-longitudinally along a portion of said workpiece, said method comprising the steps of:
clamping said workpiece between first and second pairs of contacts at first and second spaced positions along said workpiece;
-clamping said workpiece between third and fourth pairs of contacts at third and fourth spaced positions between said first and second positions respectively with said third and fourth positions each being disposed adjacent an end of said slot-like area; and,
causing an electrical current to flow through said workpiece between said first and third pairs of con- :tacts and through said workpiece between said second and fourth pairs of contacts.
2.The method as defined in claim 1 further including thesteps of removing said third and fourth pairs of contacts from. said clamping positions when the portions of said-workpiece disposed between said first and third pairs of contacts and said second and fourth pairs of contacts have been heated to a predetermined desired temperature; and,
causing an electrical current to flow through said .workpiece between said first and second pairs of contacts to heat said elongated workpiece to a pre- I .determined desired temperature.
3. Themethod as defined in claim 1 wherein said step of clamping said workpiece at first and second spaced positions comprises the step of clamping said workpiece adjacent the ends thereof.
4. A method of heating an elongated workpiece hav-- ing first and second terminal end portions "and an intermediate portion having an aperture therein, said workpiece in electrical contact with one of said terminal end portions; placing a second contacta'gains't said workpiece in electrical contact with the other of'said terminal end portions; placing a third contact against said workpiece in electrical contact with said intermediate portion at the end of said aperture adjacent said one of said terminal end portions; placing a fourth contact against said workpiece in electrical contact with said intermediate portion at the end of said aperture adjacent said other of said terminal end portions; causing an electrical current to flow through said workpiece between said first and said third contacts; and, causing an electrical current to flow through said workpiece between said second and said fourth contacts.
6. The method as defined in claim 5 wherein the step of resistance heating substantially the entire workpiece comprises the steps or removing said third and said fourth contacts from electrical contact against said intermediate portion and causing an electrical current to flow through said workpiece between said first and said second contacts.
7. An apparatus for resistance heating an elongated workpiece having at least one slot-like area extending longitudinally therealong, said apparatus comprising:
first and second spaced apart pairs of contacts, each pair having a first opened condition and a second workpiece clamping and heating condition wherein when said firstand second pairs of contacts arein said second condition, said first pair of contacts engages said wOrkpiece adjacent one end thereof and said second pair of contacts engages said workpiece adjacent the other end thereof;
first means for selectively forcing said first and second pairs of contacts between said first and second conditions;
third and fourth pairs of contacts spaced between said first and second pairs of contacts respectively and from each other, each of said third and fourth pairs of contacts having a third opened condition and a fourth workpiece clamping-and heatingco'ndition wherein when said third and fourth'contacts are in said fourth condition, said thirdpair of con first means for supplying electrical current to saidfirst and third pairs of contactswhen' said first pair of contacts is in said second condition and said third pair of contacts is in said fourthcondition; and, 4 second means for supplying electrical current to said" second and fourth pairs of contacts when said-second pair of contacts is in said second condition and said fourth pair of contacts is in said fourth condition.
8. The apparatus as defined in claim 7 further including third means for supplying electrical current to said first and second pairs of contacts when said first and second pairs of contacts are in said second condition and said third and fourth pairs of contacts are in said third condition.
9. The apparatus as defined in claim 8 wherein said first, second and third supplying means comprise a single supplying means selectively controllable for supplying electrical current to said first and third, said second and fourth and said first and second pairs of contacts.
10. In an apparatus for resistance heating an elongated workpiece having first and second terminal end portions and an intermediate portion having an aperture with'two longitudinally spaced terminal areas, one terminal area facing said first end portion and the other terminal area facing said second end portion, said apparatus including first and second spaced contacts, first means for selectively forcing said first and second contacts between a spaced apart condition and an electrical contacting condition with said workpiece at said first and second terminal end portions respectively and first means for causing electrical current flow through said workpiece between said first and second contacts, the improvement comprising:
a third contact including second means for selectively forcing said third contact between a spaced apart condition and an electrical contacting conditiOn with said workpiece at said one terminal area;
a fourth contact including third means forselectively forcing said fourth contact between a spaced apart condition and an electrical contacting condition with said workpiece at said other terminal area;
means for selectively causing an electrical current flow through said workpiece between said first and third contacts when said first and third contacts are in said contacting conditions; and,
means for selectively causing an electrical current flow through said workpiece between said second and fourth contacts when said second and fourth contacts are in said contacting condition.
11. The improvement as defined in claim 10 wherein said third and fourth contacts each comprise a pair of contacts, at least one contact in each of said pairs being selectively movable relative to the other contact in said pairs between said spaced apart conditions and ,said
electrical contacting conditions. r
Claims (11)
1. A method of resistance heating an elongated workpiece having at least one slot-like area extending generally longitudinally along a portion of said workpiece, said method comprising the steps of: clamping said workpiece between first and second pairs of contacts at first and second spaced positions along said workpiece; clamping said workpiece between third and fourth pairs of contacts at third and fourth spaced positions between said first and second positions respectively with said third and fourth positions each being disposed adjacent an end of said slot-like area; and, causing an electrical current to flow through said workpiece between said first and third pairs of contacts and through said workpiece between said second and fourth pairs of contacts.
2. The method as defined in claim 1 further including the steps of removing said third and fourth pairs of contacts from said clamping positions when the portions of said workpiece disposed between said first and third pairs of contacts and said second and fourth pairs of contacts have been heated to a predetermined desired temperature; and, causing an electrical current to flow through said workpiece between said first and second pairs of contacts to heat said elongated workpiece to a predetermined desired temperature.
3. The method as defined in claim 1 wherein said step of clamping said workpiece at first and second spaced positions comprises the step of clamping said workpiece adjacent the ends thereof.
4. A method of heating an elongated workpiece having first and second terminal end portions and an intermediate portion having an aperture therein, said method comprising the steps of: resistance heating said terminal end portions; and, resistance heating substantially the entire workpiece including said terminal end portions and said intermediate portion.
5. The method as defined in claim 4 wherein the step of resistance heating said terminal end portions comprises the steps of placing a first contact against said workpiece in electrical contact with one of said terminal end portions; placing a second contact against said workpiece in electrical contact with the other of said terminal end portions; placing a third contact against said workpiece in electrical contact with said intermediate portion at the end of said aperture adjacent said one of said terminal end portions; placing a fourth contact against said workpiece in electrical contact with said intermediate portion at the end of said aperture adjacent said other of said terminal end portions; causing an electrical current to flow through said workpiece between said first and said third contacts; and, causing an electrical current to flow through said workpiece between said second and said fourth contacts.
6. The method as defined in claim 5 wherein the step of resistance heating substantially the entire workpiece comprises the steps or removing said third and said fourth contacts from electrical contact against said intermediate portion and causing an electrical current to flow through said workpiece between said first and said second contacts.
7. An apparatus fOr resistance heating an elongated workpiece having at least one slot-like area extending longitudinally therealong, said apparatus comprising: first and second spaced apart pairs of contacts, each pair having a first opened condition and a second workpiece clamping and heating condition wherein when said first and second pairs of contacts are in said second condition, said first pair of contacts engages said wOrkpiece adjacent one end thereof and said second pair of contacts engages said workpiece adjacent the other end thereof; first means for selectively forcing said first and second pairs of contacts between said first and second conditions; third and fourth pairs of contacts spaced between said first and second pairs of contacts respectively and from each other, each of said third and fourth pairs of contacts having a third opened condition and a fourth workpiece clamping and heating condition wherein when said third and fourth contacts are in said fourth condition, said third pair of contacts engages said workpiece adjacent one end of said slot-like area and said fourth pair of contacts engages said workpiece adjacent the other end of said slot-like area; means for selectively forcing said third and fourth pairs of contacts between said third and fourth conditions; first means for supplying electrical current to said first and third pairs of contacts when said first pair of contacts is in said second condition and said third pair of contacts is in said fourth condition; and, second means for supplying electrical current to said second and fourth pairs of contacts when said second pair of contacts is in said second condition and said fourth pair of contacts is in said fourth condition.
8. The apparatus as defined in claim 7 further including third means for supplying electrical current to said first and second pairs of contacts when said first and second pairs of contacts are in said second condition and said third and fourth pairs of contacts are in said third condition.
9. The apparatus as defined in claim 8 wherein said first, second and third supplying means comprise a single supplying means selectively controllable for supplying electrical current to said first and third, said second and fourth and said first and second pairs of contacts.
10. In an apparatus for resistance heating an elongated workpiece having first and second terminal end portions and an intermediate portion having an aperture with two longitudinally spaced terminal areas, one terminal area facing said first end portion and the other terminal area facing said second end portion, said apparatus including first and second spaced contacts, first means for selectively forcing said first and second contacts between a spaced apart condition and an electrical contacting condition with said workpiece at said first and second terminal end portions respectively and first means for causing electrical current flow through said workpiece between said first and second contacts, the improvement comprising: a third contact including second means for selectively forcing said third contact between a spaced apart condition and an electrical contacting conditiOn with said workpiece at said one terminal area; a fourth contact including third means for selectively forcing said fourth contact between a spaced apart condition and an electrical contacting condition with said workpiece at said other terminal area; means for selectively causing an electrical current flow through said workpiece between said first and third contacts when said first and third contacts are in said contacting conditions; and, means for selectively causing an electrical current flow through said workpiece between said second and fourth contacts when said second and fourth contacts are in said contacting condition.
11. The improvement as defined in claim 10 wherein said third and fourth contacts each comprise a pair of contacts, at least one contact in each of said pairs being selecTively movable relative to the other contact in said pairs between said spaced apart conditions and said electrical contacting conditions.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US17793271A | 1971-09-07 | 1971-09-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3737618A true US3737618A (en) | 1973-06-05 |
Family
ID=22650512
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US00177932A Expired - Lifetime US3737618A (en) | 1971-09-07 | 1971-09-07 | Method and apparatus for resistance heating slotted tubes |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3737618A (en) |
| CA (1) | CA941025A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5744773A (en) * | 1995-09-19 | 1998-04-28 | Newcor, Inc. | Resistance heating process and apparatus |
| US6037558A (en) * | 1998-06-30 | 2000-03-14 | Newcor, Inc. | Integrated low inertia projection welding head and cylinder |
| US20030217991A1 (en) * | 2002-03-22 | 2003-11-27 | Benteler Automobiltechnik Gmbh | Method of and apparatus for the electrical resistance heating of metallic workpieces |
| US20070215588A1 (en) * | 2006-03-16 | 2007-09-20 | Noble International, Ltd. | Method and apparatus for the uniform resistance heating of articles |
| US20100285328A1 (en) * | 2008-05-16 | 2010-11-11 | Toyota Jidosha Kabushiki Kaisha | Press-forming method and press-formed part |
| US20160136712A1 (en) * | 2013-06-05 | 2016-05-19 | Neturen Co., Ltd. | Heating method, heating apparatus, and hot press molding method for plate workpiece |
| US20180054859A1 (en) * | 2016-08-17 | 2018-02-22 | Ratier-Figeac Sas | Heating device |
| US20180070409A1 (en) * | 2009-08-07 | 2018-03-08 | Radyne Corporation | Heat Treatment of Helical Springs or Similarly Shaped Articles by Electric Resistance Heating |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1299931A (en) * | 1918-08-13 | 1919-04-08 | Gen Electric | Metal-heating device. |
| US1324001A (en) * | 1919-12-02 | Hugh a | ||
| US1344961A (en) * | 1919-10-04 | 1920-06-29 | Thomson Electric Welding Compa | Electric metal-working apparatus |
| US2969448A (en) * | 1959-03-03 | 1961-01-24 | Continental Can Co | Heater vaporizer element support |
-
1971
- 1971-09-07 US US00177932A patent/US3737618A/en not_active Expired - Lifetime
-
1972
- 1972-07-26 CA CA147,982A patent/CA941025A/en not_active Expired
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1324001A (en) * | 1919-12-02 | Hugh a | ||
| US1299931A (en) * | 1918-08-13 | 1919-04-08 | Gen Electric | Metal-heating device. |
| US1344961A (en) * | 1919-10-04 | 1920-06-29 | Thomson Electric Welding Compa | Electric metal-working apparatus |
| US2969448A (en) * | 1959-03-03 | 1961-01-24 | Continental Can Co | Heater vaporizer element support |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5744773A (en) * | 1995-09-19 | 1998-04-28 | Newcor, Inc. | Resistance heating process and apparatus |
| US6037558A (en) * | 1998-06-30 | 2000-03-14 | Newcor, Inc. | Integrated low inertia projection welding head and cylinder |
| US20030217991A1 (en) * | 2002-03-22 | 2003-11-27 | Benteler Automobiltechnik Gmbh | Method of and apparatus for the electrical resistance heating of metallic workpieces |
| US6897407B2 (en) * | 2002-03-22 | 2005-05-24 | Benteler Automobiltechnik Gmbh | Method of and apparatus for the electrical resistance heating of metallic workpieces |
| WO2007109546A3 (en) * | 2006-03-16 | 2008-03-20 | Noble Int Ltd | Method and apparatus for the uniform resistance heating of articles |
| WO2007109546A2 (en) * | 2006-03-16 | 2007-09-27 | Noble Advanced Technologies, Inc. | Method and apparatus for the uniform resistance heating of articles |
| US20070215588A1 (en) * | 2006-03-16 | 2007-09-20 | Noble International, Ltd. | Method and apparatus for the uniform resistance heating of articles |
| US7714253B2 (en) * | 2006-03-16 | 2010-05-11 | Noble Advanced Technologies, Inc. | Method and apparatus for the uniform resistance heating of articles |
| US20100285328A1 (en) * | 2008-05-16 | 2010-11-11 | Toyota Jidosha Kabushiki Kaisha | Press-forming method and press-formed part |
| US9003857B2 (en) * | 2008-05-16 | 2015-04-14 | Toyota Jidosha Kabushiki Kaisha | Press-forming method and press-formed part |
| US20180070409A1 (en) * | 2009-08-07 | 2018-03-08 | Radyne Corporation | Heat Treatment of Helical Springs or Similarly Shaped Articles by Electric Resistance Heating |
| US11044788B2 (en) * | 2009-08-07 | 2021-06-22 | Radyne Corporation | Heat treatment of helical springs or similarly shaped articles by electric resistance heating |
| US20160136712A1 (en) * | 2013-06-05 | 2016-05-19 | Neturen Co., Ltd. | Heating method, heating apparatus, and hot press molding method for plate workpiece |
| US20190030584A1 (en) * | 2013-06-05 | 2019-01-31 | Neturen Co., Ltd. | Heating method, heating apparatus, and hot press molding method for plate workpiece |
| US20180054859A1 (en) * | 2016-08-17 | 2018-02-22 | Ratier-Figeac Sas | Heating device |
Also Published As
| Publication number | Publication date |
|---|---|
| CA941025A (en) | 1974-01-29 |
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