US2202758A - Apparatus for progressive heat treatment - Google Patents

Description

y 1940. F. s. DENNEEYN ET AL 2,202,758

APPARATUS FOR PROGRESSIVE HEAT TREATMENT Original Filed Sept. 24, 1934 3 Sheets-Sheet l I as v INVENTORS y 28, 1940- F. s. DENNEEN ET AL 2,202,758

APPARATUS FOR PROGRESSIVE HEAT TREATMENT Original Filed Sept. 24, 1934 3 Sheets-Sheet 2 35 5 3 K 55% s&% 5 I J I I 3 Z 4 /IIIIIIIIIIIIIIIIIIII'/Z 5 z INVENTORS jg%%azaaJda iawwzba m V. Y L.

May 28, 1940. F. s. DENNEEN El AL 2,202,758

APPARATUS FOR PROGRESSIVE HEAT TREATMENT Original Filed Sept. 24, 1934 3 Sheets-Sheet 3 III? g /42 III/ /A {w M Patented May 28, 1940 UNITED STATES PATENT OFFICE APPARATUS FOR PROGRESSIVE HEAT TREATMENT corporation of Ohio Application September 24, 1934, Serial No. 745,194 Renewed November 9, 1938 29 Claims.

The present invention, as a further improvement on that shown and described in our copending application Serial 689,904, relates, as indicated to apparatus for progressive heattreatment, and illustrates one form of apparatus suitable for following the method and producing the article described and claimed in our application Serial No. 745,195 entitled Progressively heat-treated article and method of producing same being filed even date herewith. This invention is particularly useful in the heat-treatment of large metal parts of cylindrical or of modified cylindrical form such as rolls, shafting and tubing and of special forms of beams, rails and other articles in which the portion desired to be heat-treated is either too large or too irregular in form to be treated in its entirety in a single momentary operation without change of position of the heating element with respect to the work.

In general, the means and method described herein for the practice of our invention pertain to the progressive heat-treatment of a part, or parts, of an article by heating, quenching, and 5 tempering, and offer particular advantages in the surface zone hardening of such articles as shafts, mill rolls, and the like. While the preferred means and method of heating, which is one of the principal steps in our process, depend 30 upon induction heating accomplished through the use of a heating element spaced from the article and supplied with alternating currents of relatively high frequency, we have shown and described other means and methods of heating that 35 may be satisfactorily used. We have further pointed out various uses for our invention whereby different results may be obtained and on articles of various shapes and made from various materials.

40 In heat-treatments there have been no teachings providing for a progressive heating and quenching of such articles which do not change the chemical composition of the metal being treated, or leave untreated areas or imperfectly 45 treated areas, or disturb physical qualities already provided in portions adjacent to those areas desired to be heat-treated.

It is to be understood that the heat-treatments described in this specification will apply to a wide range of metals other than ferrous metals and that the results may be of a widely varying nature, but readily controlled by the apparatus employed and the various possible methods of its use.

Heretofore, when cylindrical articles were heattreated, such as for surface hardening or surface annealing, it was necessary to heat all parts of the entire surface substantially simultaneously and to quench likewise by a process applying simultaneously to all parts heated, otherwise Ii there would be laps or joints in which the hardness would differ from that of the remainder of the area heat-treated. In case of large articles, this required large and expensive apparatus, and

a heavy consumption of power and usually pro- 10 duced irregular and unsatisfactory results. This was particularly true in the treatment of cylindrical pieces having a step or shoulder and in which it was desired to heat-treat the cylindrical surface to, but not into, the region of the shoulder.

Furthermore, the treatment of tapered or otherwise modified portions of an article would require specially formed heaters or heating elements which would be diflicult to adapt to other 20 portions of the article and would require special quenching means as well. There has been, heretofore, no automatic means for progressively changing the form of heating or quenching elements in passing from one part of the article to another.

In addition, in changing from one portion of the article to another, the power required usually changes, due to a change in the amount of metal exposed to the heating effect. In applications heretofore used, this change required more or less complicated adjustments in the various circuits pertaining to the supply source of the heating current. Further, no means has heretofore been provided for distributing the necessary power output between two or more elements heating different parts of the article simultaneously. As has been pointed out in co-pending application Serial No. 718,003, it is highly important in zone hardening the surface of a steel article that the heating of the zone to the correct temperature for quenching'be accomplished at so high a rate that there will be insuflicient time for the heat to travel appreciably beyond the zone to be hardened. Further, the quenching must be vigorous and must be accomplished immediately when the zone has reached the proper temperature and the cooling accomplished almost instantaneously. Only in this way is it possible to obtain a strong intimate bond area between the hardened zone and the core, for if high rate 01. heating and of cooling are not accomplished, appreciable quantities of free ferrite will form in the bonding area greatly injuring the strength of the bond. Another important need for high rate of heating and quenching is that with slower heating the heat penetrates a considerable distance beyond the zone to he hardened, snaking immediate quenching impossible due to the thickness of the layer through which the heat must be removed and, too, where substantially all of the heat cannot be immediately removed in the quench the heat in the areas removed from the zone will travel back into a part of the zone where hardening has already been accomplished, tempering or softening that part of the zone, thereby undoing a part of the hardening that had been accomplished. In our invention we have provided means and method for accomplishing both the desired high rate of heating and high rate of cooling. I

This invention has for its chief object the provision of apparatus whereby an article may be progressively heat-treated. Another object of this invention is to provide means for controlling a progressive method of heat-treatment whereby a region adjacent to a shoulder of an article may be treated in uniformity with other parts of the treated surface. A further object is to provide means for progressively and simultaneously both hardening and tempering an article. An additional object is to provide means for uniformly distributing heat over an article of varying form thus progressively being heat-treated. A still further object is to provide means for automatically varying the position of heating elements during the heating interval. Another object is to provide means for progressively transferring the heating effect and in varying amount from one heating element to another and thus to transfer the heating effect from one part of the article to another.

With these and other objects in view which will appear as the description proceeds, said invention then consists of the apparatus hereinafter explained and the method of use of this apparatus and such modifications of them as will produce the results described. We desire to have it understood that the invention is not limited to the details of construction and arrangement of parts illustrated in the accompanying drawings as the invention is capable of many other embodiments, and the phras'eology employed is for the purpose of description and not for limitations.

In said annexed drawings:

Fig. 1 is a diagrammatic elevation partly in section showing the elements of our improvement applied to a plain cylindrical object. Fig. 2 is a view in the direction indicated at section 2-2 of Fig. 1. Fig. 3 is a diagrammatic elevation similar to Fig. l but showing modified parts. Fig. 4 is an elevation similar to Fig. 3 but of a still further modification. Fig. 5 is an elevation, partly in section, showing the general arrangement of an automatic means for heat-treating a stepped cylinder. Fig. 6 is a section on line 66 of Fig. 5. Fig. 7 is a section similar to Fig. 6 but showing a modified form of heater. Fig. 8 is a view similar to Fig. 3 but showing an alternative heating means. showing an alternative quenching means. Fig. 10 is a section on an enlarged scale of the upper heating element. Mg. 111 shows a modification of the device illustrated in Fig. 4. Mg. 12 shows a modification of the apparatus adaptable to the heat treatment of pipes or tubes.

In Fig. 1 the cylindrical article it to be treated is supported the cable or red ii and eye it in such a Way as to he lowered at at any ether d si ed rate.

more tide Fig. 9 is a view similar to Fig. 3 but Fears i3 definitely secured in place are employed as means for guiding the direction of the cylinder in its movement. the arms 86 and il serving as. intermediate members for holding the cylinder in definite position relative to the guide bar and sliding thereon. The cylinder is provided with an extension I! serving as a guide bearing and the shank I! of the eye l2 serves as a guide hearing at the opposite end of the cylinder. These bearings, being in alignment, permit the cylinder to rotate when a rotating or oscillating motion is given to the supporting cable or rod ll.

Secured to the guide bar, or to some other part of the structure carrying the guide bar, are the heating and quenching elements. When correctly arranged relative to each other and to the article to be heat-treated, and supplied with the correct amount of heating energy and refrigerant, these being supplied at the proper time and rate for the article being heat-treated, this device will produce almost any desired heat-treatment consistent with the material of the article.

In operating the device shown in Fig. 1, and assuming it is desired to heat-treat the surface of the cylindrical article shown for its entire length, the lower end of the article is first brought to a line above the heating element I8 and the article is then lowered or passed for its full length through the entire series of heating and quenching elements. The heating element It ordinarily is supplied with low frequency current and serves as a pre-heating means only for the surface metal of the cylinder as it enters the group of heating and quenching elements. Under many conditions, however, the use of the pre-heating element may be entirely dispensed with. The portion of tlie surface thus pre-heated enters the preferably water cooled heating element I9 which is preferably supplied with current having a frequency appreciably higher than 60 cycles so com monly used in electrical supply circuits and is brought to a relatively high temperature before this surface emerges from this last element. The portion of the surface thus heated passes the insulating shield 20 and then enters the annular quenching ring 2| from which quenching fluid is projected vigorously onto the heated surface through orifices 22 which are directed in any suitable way to help prevent the fluid from rising upwardly and passing the edge of the shield 20.

As the cylinder continues to move downwardly the quenched portion passes the shield ring 23 and enters the heating element 24 which reheats the surface to any desired degree after which it is permitted to cool in the air or any other atmosphere. This, in the case of a ferrous material, tempers the surface hardened by the preceding heating and quenching. The shank I! of the supporting eye is made of sufficient length to permit the upper edge of the cylinder to pass completely through the tempering ring 24 before arm i4 reaches heating element l8.

The foregoing procedure is particularly applicable in the case of an article made of steel having a carbon content of approximately .35 or more and will produce a surface zone of substantially uniform hardness and substantially free from objectionable strains that may have been set up during the hardening process and substantially free from certain other strains that may have existed prior to hardening.

Articles made from a Wide variety of different materials including metallic as well as non-metallic, react diiferentiy when subjected to this presses. For instance, co seer, brass, or bronze articles may be appreciably softened or annealed by the heating and subsequent quenching herein described. Depending upon the material in the article and the results desired to be obtained, the use of either the pre-heating element I. or the tempering element 24 or both of these may be omitted.

When it is desired to heat-treat a shaft having a shoulder as illustrated in Fig. 3, a somewhat different arrangement of heating elements or heaters is desirable. In this figure the actuating and guiding means for the cylinder are not shown but may be made similar to those illustrated in Fig. 1.

- In the device shown in Fig. 3 the upper heater 25 is so formed at 26 as to reduce as much as possible the heating of the face 21 of the shoulder when this shoulder comes into its position of closest proximity with this heater. This heater has an inner annular chamber 28 and an outer annular chamber 29. The inner chamber carries quenching fluid and the inner annular wall has perforations 30 for projecting this fluid onto the walls of the cylindrical articles 3|. The outer annular chamber 29 serves as a cooling jacket for the heater itself.

Below heater 25, but separated from it by insulating ring 33, is the heater 34. Immediately below heater 34 is the insulating shield ring 35 which also serves as a spacer for the annular quenching ring 36. As both heaters 25 and 34 supply heat simultaneously for the surface of the cylinder 3| the heating of this surface progresses as the cylinder 3| is moved relative to the heaters, the surface temperature of the cylinder being least at the entrance to the upper heater and being greatest adjacent to the shield ring 35. By regulating the relative inputs of energyto the two heaters at the time shoulder 21 reaches its limiting position relative to heater 25, the rate of heating of heater 34 is reduced and that of heater 25 is increased so that for a short interval after the cylinder 3| has stopped in its axial movement, the heating is distributed substantially evenly over the surface enclosed by the heaters. At the termination of this heating interval, quenching liquid is projected onto this surface. usually through orifices such as 30 and the entire convex surface is thus heated and quenched to produce substantially uniform physical properties. Fig. 10 illustrates means for using chamber 28 as a cooling jacket. In this the annular space 28' carries the cooling and quenching fluid which, during the heating and idle intervals, is filled with this fluid circulating under relatively low pressure. At the instant quenching is required, this pressure is suddenly increased by any suitable means and valves 30' which may be numerous and assume a variety of forms, and which are held closed normally by resilient means such as spring 29', quickly open, spraying large quan tities of quench onto the heated surface of the cylinder 3| and cooling it very suddenly. It will be evident that the heater 34 may be omitted and approximately the same results will be obtained.

For the purpose of automatically regulating the heating as this heating progressively approaches the shoulder of a shaft or other cylindrical form, the heating elements or heaters may be made in the form of a flexible and variable helix as shown at 38 in Fig. 4. Suitable current is supplied at the terminals 39 and 40. This helical conductor is supported by the quenching ring 4|, suitable insulation being employed as at 42. As the cylindrical article 43 passes into this helix it is heated by the coils and as it emerges is quenched by the fluid from ring 4|. When shoulder 44 engages the upper part of the helix through insulation 45, the helix is compressed and more and more heat! ing is concentrated adjacent to the shoulder causing the depth of heating to become equalized. At the time the spaced coils reach a substantially closed relationship the heating is completed. All the heated surface above the ring 4| is then quenched rapidly and uniformly by a sudden increase of pressure within the hollow conductors causing a joint line extending along the inner part of the helix at 4| of Fig. 11 to open by wall deflection as indicated by the broken lines at 4|" along its entire length and quickly flooding all the surface of the cylinder still remaining unquenched. As an alternative or supplemental quenching means, a system of nozzles as at 42' of Fig. 11 may be arranged to project streams of quenching fluid through the helical space between the coils and onto the heated surface, the quench being supplied by a series of circumferentially spaced headers 43" fed by piping such as 44'.

As it is frequently desired to heat treat cylindrical articles having tapered portions or portions of a modified form and to apply this heattreatment to large quantities of these articles, an automatic heating and quenching mechanism is desirable. Such a mechanism is shown in Fig. 5. In this mechanism, the cylinder 46 to be heat-treated is secured to the screw shaft 41 so as to be suspended thereby and to rotate therewith. The lower end of the cylinder is centered as at 48 to insure against any irregular or eccentric movements. At the upper end of the screw shaft and secured thereto is the gear 49. Meshing with gear 49 is the gear 50 having a face of sufflcient width to permit its engagement with gear 49 through the latters entire range of axial movement. Gear 50 is carried on shaft 5| which has worm wheel 52 keyed thereto. The worm 53 meshes with worm wheel 52 and is driven by a motor (not shown) carried on the frame of the machine. Screw shaft 41 engages sleeve 54 which is provided with external screw threads to engage the metal of theframe of the machine at 55 as well as with internal threads to engage the shaft 41. The leads of the internal and external threads of sleeve 54 are' different so as to produce different rates of axial movement of the cylinder depending on whether sleeve 54 is held stationary by a friction brake 54' engaging the radial flange thereof as shown or whether the stop pin 55 has engaged the sleeve and has caused it to rotate with the shaft, thereby overcoming the resistance of the brake. Stop pin 56 may be moved to another position as at 55 to change the position where a different rate of axial movement starts.

As the motor driven gearing, above described, causes the screw shaft 41 carrying the cylinder 46 to descend, the yoke 51 secured to the guide bar 58 and in engagement with the annular groove provided by the collar 59 at the lower end of screw shaft 41, causes this guide bar to descend with the cylinder and through the stock 60 carried at the lower end of this bar maintains the center 5| in engagement with the cylinder at 48 thus insuring concentric axial movement of the cylinder.

Supported in the lower part of the machine by guide block 52 carried on the frame 53 of the machine are the heaters 64 and 55. Each of these heaters is made up in sections as shown at 65, 61 and 68 of Fig. 6. The guide bar 58 maintains the section 66 in correct location and other also of rectangular section prevent the heater sections from rotating and thus cause them to have only a radial movement relative to the cylinder. These guide bars are insulated from the heaters and are provided with pressure blocks l2 and guided springs it for maintaining the heaters in contact with the keys or cams. Each of the heater sections has a portion it formed to properly engage its controlling cam or key.

The heater sections 6E5, 671 and 88 are provided with interengaging portions at if and it to insure a substantially continuous form and with flexible conductors at ll and ill. The inner contours of the sections as at l9 are made to approximate the average form of the tapered or otherwise formed portion of the cylinder so that the heating will be substantially uniform around its periphery, the rotation of the cylinder during the heating interval compensating for any lack of uniformity which. may otherwise be present.

In the modification shown in Fig. 7 the heater is a single loop which may be made in numerous ways, either from a single piece of material or in composite form as shown. The inner portion 8d which may be a. laminated member conducts current in close heating relationship to the cylinder 46 and theouter supporting element 8i which may serve as-a cooling jacket is made of varying radial thickness so that the heater. as a whole, in opening and closing through a reasonable range; will maintain a. substantially circular interior form thus making it'possible to provide for a uniform air gap and uniform heating, even if the cylinder were not rotated during the heating interval. To maintain a uniform gap as the heater opens and closes, this opening and closing is definitely controlled by guide bars 82 and 83 similar to' guide bars 58, 69 and HI and which are likewise provided with cam members such as 85 and 85. In this construction the guide bars are Provided with a limited amount of rotative freedom for purpose of self alignment. Springs 86 and'.-spring seats 81 are provided similar to the construction shown in Fig. 6 for maintaining contact with the cams. Both the heaters shown in Figs. 6 and 7 may be made in multiple as shown at 64 and 65 of Fig. 5 or as shown in Figs. 1 and 3, the guide bars and cams being arranged to control each heater separately.

Means for supplying cooling and quenching fluid are illustrated in Fig. 5. Fluid for the lower heater is supplied from pipe 88 through valve 89 and pipe 80. Similarly, fluid from pipe 9i through valve 92 and pipe 93 is supplied to the upper heater. In this construction, the extension 94 on the stock 68 engages the arms 95 and 96 of the valves as the stock moves downward during operation thus first closing valve 89 and subsequently opening valve 32 after the shoulder 91 of the cylinder has approached closely enough to heater ill and the surface of the cylinder adja= cent to the shoulder has been suihciently heated.

As indicated in Fig. 5, current is supplied to the heaters hy conductors lid and 9E] connected FIX ltl

lilli secured to a suitable frame till. The axial movement of the primary readily controls the flux threading through the two or more parallel single turn elements of the secondary and thus controls the current and power output of these elements. By the upward movement of this primary coil, the current delivered to the lower heater 65 may be reduced and that delivered to upper heater increased. By a sunlcient move ment of this primary, currentfrom coil llli may be reduced substantially to zero and this move= ment of the primary coil thus may-be used to en= ergize or de-energize one or the other of the secondary circuits. By this means a very convenient and rapid change in current in heaters 64 and 85 is accomplished without arcing and without any serious disturbances in the cir-= cuits, thus making it possible to increase the rate of heating from heater 64 as this heater is approached by the shoulder 9'5 and simultaneously reducing the heating effect of heater 65 thus making a uniform heating and quenching of the entire cylindrical and conical part of the work possible. By varying the spacing of the coils in the primary member of the transformer a wide variation in the energy delivered by the secondary member may be accomplished.

For the purpose of making the operation of this transformer control automatic, arm I85 which. is hinged at 8 on a bracket I89 on the frame of the machine is engaged by the end ll of the yoke 51 .as the work is lowered and thus raises the primary coils I02 at the desired rate. 'By making the end ill of arm I05 adjustable or by providing adjustments on the end it of the yoke, the timing and rate of movement of the primary coils and the resulting secondary currents are accurately and conveniently controlled.

Variations in the form and extent of the areas to be hardened on article 46 may require controls more accurate and capable of more sensitive regulation than those provided by the movement of the primary coil I02. To the accomplishment of this, an automatic control which regulates the total energy delivered to the primary is provided. This comprises the cam H2 replaceably and adjustably carried on shaft H3. Shaft H3 is driven by gear H4, this gear being actuated by the rack H5 integral with or secured to the guide bar 58 which moves at the same rate as the work being hardened. The rotation of cam i ii actuates the plunger M6 in the carrier bracket 0 ll, compressing the return spring i it and causing rod H9 to rotate lever E20, this lever being carried by shaft i2l. As the lever ltd is moved by action of the cam it'd, the lever end 522 contacts with the rheostat resistance 823, van'irig and corrtrolling the current delivered by the exciter it"! to the generator field H25, thereby controlling the output of the generator 025 which supplies the energy to the leads ltd and tilt of the primary coil m2. lit will he understood that the cam it would he so shaped and timed that the energy delivered to the heating elements would be varied and controlled so as to maintain the correct rate and intensity of heating even though the dimensions or. form of -the surface being heated be constantly changing.

In some, applications of this apparatus, it may be found desirable to enclose the mechanism or certain parts of it. In this event the frame of themachine will be extended as indicated by broken lines at I26. It will be understood that this may enclose the transformer and the heaters as well as the other parts of the mechanism. When a full enclosure is employed, an opening is provided for retracting the work and its supporting structure, such opening being closed during operation by the cover indicated by broken lines at I26 In some instances where electric energy of suitable character is not available for heating the article, combustion means may be employed as illustrated in Fig. 8. In this construction an annular burner I2! preferably water cooled, and having suitable mixing nozzles I28, surrounds the article I29 to be heat-treated, This burner may consist of a series of individual nozzles either fixed as at I33 or adjustable as at I28, or the burner may have a relatively thin continuous aperture all the way around, that will produce a sort of ribbon form heating flame extending completely around the article. Fuel, which may be a gas, a liquid, or a finely divided solid, is introduced through the space I30 within the burner and the flame is projected with considerable intensity against a relatively narrow zone of the article. The shield I3I of heat resisting material serves as a means of limiting the downward projection of the flame. As the heated zone passes downwardly past the shield I3I it enters the space within the ring type quenching manifold I32 from which cooling fluid is projected vigorously and continuously onto the heated surface during the time the article is traveling through this manifold. Under certain conditions it may be desirable to rotate the article I29 in addition to traversing it through the heating and quenching elements.

In Fig. 9 the article I34 is progressively heated as it passes the heater I35 and the surface zone is quenched and hardened as the heated article is lowered into the tank I36 containing quenching medium I31, a deflector I38 serving to aid in preventing the quenching medium from interfering with the heating.

The processes herein described have further advantage over other processes in that the heating is so rapid and by the use of sufficiently high frequency in the electric supply source may be confined to so shallow a zone that the heated zone may be quenched and cooled almost instantaneously so that with the use of steel of the proper analysis and characteristics, practically any desired degree of hardness may be obtained. Further, the heating and cooling is accomplished at so high a rate that practically no free ferrite forms in the bond area between the hardened zone and the core, thus obtaining maximum strength and insuring against fracture or breakage of the hardened zone. It is well known that when an article has been hardened by heating and immediate and thorough quenching so as to produce extreme hardness, severe strains are set up which, if not properly relieved by tempering or drawing, result in checks or cracks that gradually increase, spoiling the surface and often resulting in complete fractureof the piece. The detrimental effects resulting from the strains set up in hardening an article increase greatly as time elapses between the hardening and drawing operations. It the drawing is properly done immediately after hardening, the detrimental effects of the hardening strains become practically negligible.

In our process we have provided means whereby this annealing may be quickly and economically accomplished immediately after the article has been hardened, the drawing action taking place progressively and immediately following the hardening, thereby practically nullifying detrimental effects that would otherwise result from hardening strains.

'While the apparatus illustrated in the accompanying drawings is shown as arranged for heat treating exterior surfaces of articles, simple modiflcations may be made whereby selected portions of interior walls in holes or recesses may be heat treated. For instance, the inside wall of a pipe or tube may be progressively heat treated by heating from within with an open ring type heater supplied with current from an alternating current source and arranged to deliver heating energy to the inner wall of the pipe, the heater and pipe being moved with respect to each other and a quenching fluid being discharged against the heated area.

Another modification in heat treating an article such as a pipe or tube would be to heat through the wall from an externally placed ring type heater as shown at I39, Fig. 12 and to quench the inside wall as it is heated to the proper temperature by projecting quenching fluid from nozzles I40 in spray head I42 which is supplied by piping I43 and I44, relative movement between the tube and the heating unit being provided for, so that the heat treating may be progressive.

Obviously, in the case of a bar or tube the article could be heat treated all the way through and progressively by heating and quenching from the outside or by heating from one side and quenching from the other.

Other modes of applying the principle of our invention may be employed instead of the ones explained, change being made as regard the means herein disclosed, provided those stated by any of the following claims or their equivalents be employed.

We, therefore, particularly point out and distinctly claim as our invention:

1. In a device for heat treating, a substantially annular current conductor serving as a heating element, the heating element embracing a part of an article to be heat treated, quenching means within said heating element, a second heating element, means for causing relative movement progressively between the aforesaid article and said heating elements during a heating interval, and cam means extending axially through a part of each heater for progressively changing the form of the heater.

2. In a device for heat treating, a. conductor in heating relationship with an article to be heat treated, said conductor comprising relatively moveable members, means for causing relative movement between said members during a heating interval, and means whereby said relative movement causes the conductor to be varied in form during said heating interval to substantially conform with a varying form of the article.

3. In a device for heat treating, a conductor in heating relationship with an article to be heat treated, said conductor comprising relatively moveable members, means for causing relative treated, said conductor comprising a series of substantially rigid connected members, means for producing relative movement between said members and said article, means for movingv said members relatively to each other during a heating interval, said last named means being controlled by mechanism operating coincidentally with the relative movement of the article and the con-' ductor.

5. In a device for heat treating, a plurality of conductors in heating relationship with an article to be heated, said conductors being in series and forming a loop surrounding the article, means for causing relative movement between said article and said conductors during a heating interval, means for relativelymoving the conductors to change the loopduring the heating interval, and means for progressively varying the current in one of said conductors, said last named meansbeing interconnected with the means for causing the relative movement. 1

6. In a device for heat treating, a conductor in heating relationship with an article to be heated, means for producing relative movement between said article and said conductor during a heating interval, and cam means for progressively varying the current in one of said conductors to correspond with variations in the relative positions of the conductor and article, said last named means being actuatedcoincidentally with the relative movement between said article and said conductor, the relative. movement being produced by an axially extending sliding cam having driving connection withzthe aforesaid cam means.

7. In a devicelfor heat treating, a. conductor in heating relationship with an article to be heated, automatic means for causing relative movement between said article and said conductor at different rates during a heating interval in accord with a pre-determined ratio, means for varying the current in said conductor during the heating interval, and quenching means.

8. In apparatus of the character described, a conductor embracing a part of an article to be heated, a support for said article, said support comprising a threaded stem attached to' the article, said stem serving as means for simultaneously rotating the article and advancing the article thru the conductor, means for supplying heating current to the conductor, and means associated with the advancing means for controlling the heating current.

9. In apparatus of the character described for heat treating an article, conductors surrounding said article, the, conductors being in substantially parallel spaced relationship, each conductor being composed of relatively movable parts, means for moving the article relative to the con ductors whereby the article passes successively through the conductors, means interconnected with the moving means for moving the relatively moveable parts of one of the conductors while the article is being moved relative thereto, passages in the conductor for projecting a quenching fluid onto said article, and valve means for controlling the flow of quenching fluid, the valve with the moving means for controlling a flow of current in the secondary of the transformer.

11. In apparatus of the character described, a substantially annular inductor extending circumferentially around a cylindrical article to be heat treated, said article being of varying diameter,

I means for rotating said article while passing it axially through the inductor, the inductor having a jacket for acooling fluid, axially extending cams slidable in said inductor for modifying the diameter-of the annular inductor to maintain a substantially uniform space between the article and the inductor, and means for controlling current being delivered to the'inductor.

12. In apparatus of the character described, a conductor extending peripherally around an article to be heat treated, means for progressively moving the article thru the conductor, an axially extending cam moving with the article, said cam displaceably engaging a part of the conductor for moving said part of the conductor transversely relative to the direction of motion of the article, and means moving with said article for operating a valve controlling a flow of cooling fluid.

13. In apparatus of the character described, a conductor extending peripherally around an article to be heat treated, a transformer supplying current to said conductor, means for progressively moving the article thru the conductor, an axially extending cam moving with the article, said cam displaceably engaging a part of the conductor, and means movingwith the article for relatively moving the primary and secondary coils of the transformer whereby current in the conductor is regulated.

14. In apparatus of the character described, a conductor extending peripherally around an article to be heat treated, a transformer supplying current to said conductor, means for progressively moving the article thru. the conductor, an axially extending member moving with the article and displaceably engaging said conductor, means moving with the article for relatively moving the primary and secondary coils of the transformer whereby current in the conductor is reduced, and means moving with the aforesaid axially extendingmember for controlling a. supply of cooling fluid to said conductor.

15. In apparatus of the characterdescribed. a conductor extending peripherally around an article to be heat treated, a transformer supplying current to said conductor, supports at opposite ends of the article, means moving said supports whereby said article passes thru the conductor, means associated with said supports for displacing a member of the transformer to control current in the said conductor, and means carried'by one of said supports for operating a valve for projecting quenching fluid onto a face or the article 16. In apparatus of the character described, a conductor extending around an article to be heat treated, means for progressively moving the article thru the conductor, the said conductor serving as means for causing heating current to flow in a surface of the article, and means for controlling the heating current, said last named means comprising a regulating a generator, an axially movable cam, the rotating cam being geared to said axially moving cam, and the axially moving cam regulating a space between the conductor and the article.

17. In apparatus of the character described, a heater extending around an article to be heat treated, and means for progressively moving said article thru said heater, said means comprising a threaded shaft, an externally threaded nut receiving the shaft, and means for limiting a movement of the shaft in the nut whereby the nut is caused to rotate and change the rate of the progressive movement of the article thru the heater.

18. In apparatus of the character described, a conductor extending around an article to be heat treated, means for progressively moving the article thru the conductor,' said means comprising a rotating threaded shaft supporting the article, an operating arm moving longitudinally with the article, a transformer supplying current to the conductor, said transformer having relatively moveable members, and means whereby the operating arm moves a member of the transformer to control current in the said conductor.

19. In apparatus of the character described, a conductor extending around an article to be heat treated, means for progressively moving the article thru the conductor, said means comprising a traveling support for the article, a longitudinally extending arbor being attached to' the support and moving therewith, said arbor having a cam, the said cam engaging a part of the conductor for varying the position of the conductor relative to an axis of the article, and means for controlling current in the conductor.

20. In apparatus of the character described, a conductor extending around an article to be heat treated, a threaded shaft being attached to the article and serving as means for moving the article thru the conductor, an externally threadednut engaging the shaft and serving as a support therefor, and braking means for resisting a movement of the nut whereby the nut is prevented from rotating with said shaft until the article has reached a predetermined position.

21. In a device for heat-treating, a substantially annular high-frequency current conductor serving as a heating element and embracing part of an article to be heat-treated, means for progressively changing the form of the conductor to vary the flux field set up thereby, quenching passages in the conductor, and means for causing substantially continuous relative axial movement between said article and said heating element during a heating interval.

22. In a device for heat-treating, a conductor in heating relationship with an article to be heat-treated, said conductor comprising elements shiftable to occupy varying relative positions, means for causing relative movement between said elements and said article, guiding means adapted to maintain spaced relationship between said elements and said article, and means for varying the form of said conductor, said means for varying the form of the conductor rotating cam for a I ductor, means to vary the being controlled by the relative movement between said elements and said article.

23. In a device for heat-treating, a conductor adapted to lie in heating relationship with an article of a varying form to be heated, means for changing the position of said conductor relative to said article during the heating interval, said means being automatically actuated by relative movement of a member with a form corresponding to the varying form of said article.

24. In apparatus of the character described, a high-frequency conductor adapted to peripherally embrace an article to be heat-treated, a support for said article, means for producing relative movement between said article and said conductor, a source of high-frequency current leading to said conductor, and control mechanism actuated by movement of the article and the conductor with respect to each other to vary both the said rate of movement and the amount of current fed to said conductor.

25. In apparatus of the character described, a variable conductor adapted to peripherally embrace an article to be heat-treated, means to supply electrical energy to said conductor to set up a flux field of pre-determined value, active on the entire zone embraced, a support for an article to be heat-treated by induction due to said flux field, mechanism operable to pass said article progressively through the flux field at a variable rate of speed, and means to automatically control the value of the flux field by varying the form of the embracing conductor and further varying the speed of movement of the article and the fiux field with respect to each other in accord with a predetermined ratio.

26. In apparatus of the character described, a conductor adapted to closely approach an article to be heat-treated, a source of high-frequency current to establish a flux field to heat said article, means to supply the current to said constrength of the fiux field in said article, a support for the article to be acted on by said conductor, mechanism to cause the supported article and the conductor to move with respect to each other, means to vary the rate of said movement, and control mechanism to automatically vary the flux value and the said rate of movement in a pre-determined manner.

27. Apparatus for heat-treating an article with a projecting shoulder comprising an inductive electric heating element adapted to encircle said article, mechanism to progressively pass part of the body portion in proximity to said element to heat part of said body, fluid quenching means adjacent said element to quench a progressively heated body portion of the article, and means to stop or retard the relative movement between the article and the heating element adjacent said shoulder to heat and quench a zone adjacent the shoulder during said stopped or retarded relative movement between the article and the heating element.

28. In apparatus of the character described, a conductor of variable form extending peripherally around an article to be heat-treated, a cam for controlling the form thereof, means for progressively advancing the article through the conductor, and means for regulating current induced in a surface zone of the article whereby heating of the said zone is controlled, said means comprising a field circuit control cam having geared connection with the cam controlling the form of the conductor.

w mauve m'im ammary with fie fm 0E; m each mmer m cmtml the current; deiivexed in said fimlmmr.

EWRANCIES S. DENNEEN.

C. DUNN. 6

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