US2261624A - Heat treating apparatus - Google Patents

Description

Nov. 4, 1941. H. v. INSKEEP v 2,261,624

HEAT TREATING APPARATUS Filed June 8, 1940 V 2 Sheets-Sheet 1 INVENTOR g i ARRY V. IN SKEEP ATTORNEY Nov. 4, 1941. I H. v. INSKEEP HEAT TREATING APPARATUS Filed June a, 1940 2 Sheets-Sheet 2 HA INVENTOR M 4,145 I BY RIRY v. INSKL.- P

ATTORNEY Patented Nov. 4, 1941 UNITED STAT-ES PATENT OFFICE HEAT 'rnmrmc APPARATUS Harry V. Inskeep, North Plainfield, N. 1., assignor to The Linde Products Company, a corpora- 7 tion of Ohio Application June s, 1940, Serial No. 339,423

15 Claims.

the critical range, and the heated surface portion is then cooled to harden the same. More. particularly, this invention relates to apparatus for heat treating, in succession, each member of a group of articles, each group comprising a pluis reduced to a minimum-and, in a sense, is negligible because the next article to be treated is placed in .positionwhile the previous article is being treated.

Among the objects of this invention are to provide apparatus for heat treating or hardening each of a plurality of similar articles quickly and expeditiously; to providesuch apparatus in which the time required for positioning and/or rallty of articles of substantially the same size replacing atreatd article with an untreated aris hardened, which results in a loss of ductility and toughness in the interior of the article; and the highest surface hardness obtainable has often been sacrificed to preserve sufficient ductility in the interior of the article. Such articles, of course, wear more rapidly than, ar-

ticles whose surfaces are hardened to a greater degree. By hardening only the surface portions subject to wear without hardening the interior of the article, the desired ductility and toughness in the interior can be retained, and, at the same time, a harder and longer wearing sur- 8 face can be provided.

Selected surface portions of a metal article can be hardened in a short time by applying localized high temperature heat, such as provided by oxyacetylene heating flames, to a, surface portion to be hardened, and then quenching the heated surface portion. However, with previous apparatus, the time consumed in placing an article to be treated in the proper position for heating and quenching is often so great that such hardening suflfers economically in comparison with continuous processes, such as furnacetieatment.

in order that-the hardening of selected 1 surface portions can compete economically with continuous processes, it is desirable that the. treatment be carried out on a production basis. More particularly, itis desirable that the'time consumed in placing an article in position for treatment be reduced to a minimum; With the apparatus of this invention, the time consumed in placing an article in position for treatment ticle is reduced to a minimum; to provide such apparatus which may be made substantially automatic in operation; to provide such apparatus.

in which the operations of heating an article to be hardened *and replacing a treated article with an untreated article are carried on simul- ,taneously; to provide such apparatus in which an article to be heated is moved into position concurrently with quenching of an article previously heated; and to provide such apparatus which will be simple in construction and emcient in operation.

Other objects and novel features of this invention will become apparent from the following description and accompanying drawings, in

which: Fig. 1 is a top plan view of apparatus constructed in accordance with this invention;

Fig. 2 is a vertical sectional view; taken' along '30 line 2- of Fig. l;

Fig. 3 is a fragmentaryv front view, taken along line 3-3 of Fig. 1, of mechanism at one end of a work support forming a part of the apparatus of Fig. 1; 5 Fig. 4 is a vertical sectional view, taken along linel4ofFlg.3;

Fig. 5 is a fragmentary front view, similar to Fig. 4, but taken along line 5-5 of Fig. 1 and showing the mechanism at the opposite end of the work support; and

Fig. 6 is a vertical sectional view, taken along line66ofFlg.5. I Referring to Figs. 1 and 2, a preferred type of apparatus constructed in accordance with this supported for reciprocatory longitudinal movementon a pedestal P; a reversible motor M for moving carriage C from left to right, and vice versa; a tank T supported by a framework F water; a work support W pivotally mounted on carriage C and provided with work holders H and H, each of' which supports for rotation an article A or A to be treated; and ,a motor M, mounted on carriage C. Motor Mflacts through invention comprises, in general, a carriage C and containing a quenching medium Q, such as gearing G to rotate the articles A and A, while selected surface portions of the same are being heated by suitable heating means, such as blowpipes B. When work support W pivots downwardly, the heated articles are immersed in quenching liquid Q, downward pivotal movement of work support W being arrested by a stop S secured to the inner wall. of tank T. Suitable mechanism, described in detail later, is operable by motor M and gearing G to cause work support W to pivot upwardly and downwardly at predetermined time intervals which are correlated with the movement of carriage C from left to right, and vice versa. The lower leg L of pedestal P is bolted or suitably secured to the floor to prevent overturning due to the overhanging weight of the various parts.

The general description of the operation of the apparatus which follows will assist in understanding the correlation and functions of the vatigous' parts, which will be described in detail la r.

With the work support W in the upper left, or full, position of Figs. 1 and 2, selected surface portions of rotating article A are heated by blowpipes B. During heating of article A, holde H is in the loading and unloading position so that the second article A may be placed in holder H. As soon as second article A is placed in holder 11, it will be started, rotating, in a manner to be described later. When the selected surface portions of article A have reached the desired temperature, after a predetermined time interval of heating, work support W is caused to pivot downwardly to the lower or dotted position of Fig. 2, thus lowering articles A and A into the quenching medium Q. The carriage C is therein' holder H is then in position for heating, and treated article A in holder H is replaced by the next, or a fourth, article to be treated while the article in holder H is being heated. The foregoing cycle of operation is repeated until all of the articles in the group have been treated. Articles A and A and the remainder of any particular group of articles treated during one setting of the apparatus, are, of course, substantially identical and require the same amounts and times of heating as well as the same amounts and times of cooling. Also, the relative location of blowpipes B with respect to the periphery of each article in such a group is substantially the same.

While the articles A and B are illustrated in the drawings as transmission shafts having a bearing area III at either end and an enlarged central portion 1 I, it will be understood that the articles may be rolls, shafts, small gears 0 pinions formed integrally with shafts or mounted on arbor's or mandrels, etc.--i. e., any article which may be rotated. during heating and-quenching. In addition, by appropriate changes in work holders H and H, any other type of article which is disposed in a single position during heating, such as the extending portion of an individual cam or selected surface portions of short bars, plates, etc., may be treated.

The outstanding features of the apparatus of this invention are the simultaneous heating of one article while a previously treated article is replaced by the next article to be treated, and the quenching of the heated article while the next article to be heated is traveling to the heating position. These features result in a tremendous saving of time and reduce the cost of treatment proportionately. Consequently, the treatment of any group of articles which are capable of treatment by apparatus having such features is rendered more economical.

For heating the articles A and A, as in Fig. 1,

1 four blowpipes may. be employed. Two outer also insures uniform and adequate quenching ,as

the heated articles pass laterally through the quenching medium, particularly when the cooling mediumis water, since there will be no oppor-- tunity for bubbles of steam to collect beneath heated surface portions.

As soon as work support W reaches the lower right position, the work support is caused to pivot upwardly to the upper right, or dotted, position of Fig. 1, thus lifting both articles out of the quenching medium. In such a position, rotating article A will be in operative relation with respect to blowpipes B so that the selected surface portions thereof may be heated, and holder H and treated article A will be in the loading and unloading position. During heating of article A, treated article A is replaced by the next or a third article to be treated. As soon as article A has been heated, the work support is again caused to pivot downwardly, dropping the heated article A into the quenching medium and again assuming the lower right position, i. ,e. beneath the dotted position of Fig. 1. Carriage C is then moved from lower right to lower left positions, i.'e. from beneath the dotted position of Fig. 1 to beneath the full position of Fig. 1, and during this movement the heated surface portions of article A in holder H will be quenched and thereby hardened. When the work support reaches the lower left position, it is again caused to pivot upwardly, thus rising to the upper left, or full, position of Figs. '1 and 2. The article blowpipes]! are adapted to heat bearing areas III,- while two inner blowpipes I3 are adapted to heat the central portions i I. Blowpipes I2 and I3 are preferably adjustably supported, and it is I to be understood that a greater or lesser number of blowpipes may be employed, and the relative positions of the same varied in accordance with the articles being treated. In addition, in treat ing articles which are not rotated but remain stationary during heating, the blowpipes B may be reciprocated during heating. Or, by suitable changes in work holders H and H, the articles themselves may be reciprocated during heating.

To provide a continuous flow of cooling medium, and a fresh supply of cooling medium at the point at which each heated article first enters the cooling medium, an inlet pipe ll, as in Figs. 1 and 2, supplies cooling medium to the bottom of tank T at the center and beneath the heating position. Warm cooling medium'is withdrawn through outlets ii at either end of the tank, these outlets being located at an appropriate height above the bottom of the tank to maintain the cooling medium at a desired level. Inlet pipe I4 is connected with a. suitable source of supply of cooling medium, such as water, oil, or a sodium hydroxide solution. Outlets I! may lead to a drain-or sewer in case the cooling medium is water, or may be connected with a suitable recirculating pump (not shown) for returning the cooling medium to inlet pipe I, in case the cooling medium is oil or "other liquidexpensive than water.

The carriage C, as in'Figs. 1 and relatively more 2, includes a vertical plate l6. Work support W, gearing G, and motors M and M" are mounted on vertical plate .|6, while V-rails or angles l1 are secured. to the upper and lower edges of plate l6 in any suitable manner, as by welding. Upper rollers l8 and lower rollers I9, respectively, engage the upper and lower rails, and are rotatably mounted rollers l8 assist in guiding the carriage during reciprocatory movement. Upper rollers l8. and lower rollers l9 are disposed opposite one another, above and below plate l6, respectively, except that there is no lower roller I9 directly below the path of travel of motor M and the upper bracket 22 directly above the path of travel of motor M is specialLv shaped to permit the motor to clear the same. The motor M is mounted on one side of plate l6, and the motor M is mounted on the opposite side of the plate, so that the two tend to balance each other. However, to prevent misalignment due to'any torque or twisting movement caused by the weight of work support W and the articles on the front side of plate l6,

intermediate rollers 21 are supported onthe rear side of plate l6 and engage the under side of the top leg of angle 26, beneath upper channel 24. Intermediate rollers 21 are rotatably mounted on stub-shafts 28 clamped in pillow-blocks 29, in turn supported by intermediate brackets 30 secured to plate l6. Consequently, carriage C is relatively easily movable, and is accurately guided by rollers l8 and I9.

Motor M, mounted in a vertical position on th rear side of plat i6, is reversible, and may either be a relatively slow-speed motor or be provided with suitable reduction means, such as a speed reducer 3|. Speed reducer 3| drives a pinion 32 which engages a rack 33, disposed in a horizontal position and secured to lower channel 25. The length of rack 33 is equal to, .or

slightly greater than, the distance through which carriage moves during reciprocation.

The work support Wincludes an integral structure comprising a back bar 35, a pair of forwardly extending arms 36 and 31 supporting at their outer ends work holder H, and a'-second pair of forwardly extending arms 38 and 39, supporting at their ends work holder H'. is adapted to pivot about a horizontal shaft 46, which passes through a suitable hole or aperture in each of arms 36, 31, 38, and 39. Shaft 48, which is rotated relatively rapidly, is journalled a sprocket 46 driven by one ofch ins 43 so as to rotate the live centers and -al 0 articles A and A". The work holders also include dead centers 41, mounted for longitudinal movement in the ends ofarms 36 and 36. Live centers 45 Work support W v in bearings 4| secured to plate I 6, and a pair of one end of which is secured to the latch 68 and from the full position vto the dotted position of engage one end, while dead centers 41 engage the opposit end, of articles A and A. To remove a treated article fromholders H and H,

or to replace 9. treated article with an untreated one, dead centers 41. are movable. inwardly and outwardly by handles--48. As in Fig. 1, brackets 49 are secured to arms 36 and 38 adjacent the outer ends thereof in any suitable manner, as by welding, and the lower ends of handles 48 are pivoted on brackets 49, as in Fig. 2. The ends of dead centers 41 are pivotally attached to handles 48 a short distance from the lower ends thereof, and dead centers 41 pass through the outer ends of brackets 49. Springs 56 are interposed between brackets 49 and abutments 5| formed on dead centers 41 to press dead centers 41 into engagement with'the articles, and also keep the articles in engagement with rotating live centers 45. By moving the upper end of one of handles 48 to the right, as in Fi 1, corresponding dead center 41 may be withdrawn to release articl A or A from the workholder.

Themotor M .is-rnounted in a horizontal position on the front side of 'plate l6, and may be provided with an adjustable speed reducer 52, provided with a. control handle 53. Speed reducer 52 is directlyconnected to shaft 40 to ro- The mechanism for causing work support W to pivot upwardly and tate articles A and A.

nalled in a bearing bracket 58 secured-to plate l6. Bevel gear 56 engages a second bevel gear 59 mounted on the end of a drive shaft 66;which is rotated relatively slowly and is journalled in bearing 6| and 62 secured to plate l6. Pinions .63 and 64 are keyed to shaft 66 adjacent bearings 6| and 62, and engage gears 65 and 66, respectively. Gears 65 and 66 are mounted on, but otherwise not connected with, shaft 46, and ro- -tate relatively slowly, due to the reductionin speed afforded by transmission from worm 54 to gear 55, and from pinions 63 and 64 to gears 65 and .66, respectively. Gears 65 and 66, 'respectively, form the primary operating part of the mechanism for lowering, an'd the mechanism for raising, the articles into and out of the quenching tank, i. e.. for causing work support W to pivot downwardly and upwardly. The relatively slow rotation of gears 65 and 66 is utilised to time the pivoting of work support W.

The details of the lowering mechanism are illustrated more clearly in Figs. 5 and 6. Since the normal tendency for work support W is to pivot downwardly into the quenching tank, due to the unbalanced weight at the front thereof, work support W is, normally held in horizontal position by a latch 68 pivoted at its upper end on an ear 69 depending from bearing 6|, the lower end of latch 68 normally engaging the upper surface of back bar'35 of work support W. Latch 68 is pressed forwardly by a coil spring 16,

the other end of which surrounds a stud .1|

mounted on plate l6. To release latch 68, gear 65 is provided with a pin 12, which is adapted to engage-the latch as the gear rotates slowly in the directionof the arrow of Fig. 6. Pin 12 is adapted to force the latch backwardly, as in movement Fig. 6. This releases the work support and per- ;mits the forward end of the work support to drop into the quenching tank, 1. e. causes work support W to pivot downwardly to the dotted position of Fig. 6. The rear of bar 85 is curved so that in 12 will pass by easily, while the rear of arm 38 may be thickened up to shoulder l3 as shown, or a suitable collar or washer interposed between arm 38 and gear 65, both to hold gear 85 in longitudinal alignment and to permit pin 12 to clear arm 38 during further rotation of gear 65. As soon as pin 12 passes downwardly below thedotted position of Fig. 6, spring 18 will force latch 68 outwardly against rear bar 35. When the work support is caused to pivot upwardly by the raising mechanism to a posi-' tion slightly above the horizontal, spring 10 will force latch 68 outwardly to the full position of Fig. 6, where the latch will again hold the work support in a horizontal position.

When the work support W is caused to pivot downwardly to the dotted position of Fig. 6, the

may be provided with a shock resistant cap 15,,

formed of rubber or other suitable material.

. The details of the raising mechanism are illustrated more clearly in Figs. 3 and 4. At the expiration of a predetermined time interval, the work support W is raised from the full position of Fig. 4 (which corresponds to the dotted posi-- tion of Fig. 6) to'the intermediate dotted position of Fig. 4, and then to the upper dotted position of Fig. 4, where the latch 68 of Figs. 5 and 6 will retain the work support in a horizontal position, as explained above. For raising the work support W, a lever '16 is pivoted on a pin TI mounted on gear 68. A leaf spring 18, one end of which is secured to a pin 18 mounted on gear 86 and the opposite end of which engages lever I8 above pin TI, normally maintains the lower end of lever 16 sufficiently close to the center of gear 66 so that as gear 86 rotates slowly, the lower and stopped only once during treatment of any particular group of articles.

Motor M may be started and stopped by a push-button switch 81, as in Fig. 1, mounted at end 01' lever 16 will catch the end ofback bar 85 and cause the work support to pivot upwardly tothe intermediate dotted position of Fig. 4. At this point, the upper end of lever I8 engages an ear 80, which functions as a cam and is formed as an extension of or is secured to the under side of bearing 62 in any suitable manner, such as by welding. Furtherrotation oi! gear 68 causes the lower end of lever 16 to be pushed outwardly away from the center of gear 86 by ear 88, thereby causing the lower end of lever 18 to begin to slide past the rear of bar 35, as in the upper dotted position of Fig. 4. At this point, latch 88 6i--Figs. 5 and 6 will be pushed forwardly and above the upper surface of bar 35, and as lever the right on tank T and from which a suitable electrical cable leads to motor M. It is preferred, however, to use switch 81 to place into and out of operation a suitable timing mechanism 89 which controls the operatic of reversing motor M. The rotation of gears 8 and 88, including the position of pin 12 and lever 16, are so correlated with this control mechanism that as the motor M is started up, to move the carriage from left to right, or vice versa, pin 12 will engage latch 68 to cause the workholder to pivot downwardly and into the quenching tank, and when the carriage C has reached the end of its traverse and motor M is stopped, the lower end of lever 18 will simultaneously engage bar 35 to cause the work support to pivot upwardly and raise from the quenching tank. Gears 65 and 66 are rotated once during the heating and quenching of a single article and or 8 R. P. M. and

or slightly less than 1% R. P. M. The articles are rotated at a speed, depending upon the size and type thereof, which normally varies within limits ranging from to 200 R. P. M. Since both the heating and quenching times and the speed of rotation normally vary in accordance with the size of the article, and changes in speed oftgears 65 and 86 thus normally correspond to changes in the speed of rotation of the articles,

changes in speed of gears 65 and 86 normally may be effected by adjustable speed reducer 52,

which at the same time adjusts the speed of rotation of articles A and A.

Due to the fact thatthe quenching time is relatively short, the blowpipe flames may be left lighted during the entire cycle, particularly when heating and quenching times of small duration are used; However, when heating times such as 25 to 30 seconds and correspondingly longer quenching times are necessary, it may be desirable to shut oil the heating flames while the carriage is traveling from left to right, and vice versa. One or. more automatically operated shut-0i! valves, such as valve 88, as in Fig. 2,

operated by a solenoid 8| which is controlled by the timing mechanism 89. may be utilized for turning the heating gaseson and oil. Also, a small lighting blowpipe may be mounted adjacent blowpipes B, so that as soon as the heating gases are turned on, the heating jets issuing from the blowpipes will be ignited.

In hardening selected surface portions of each of a group of similar or substantially identical articles, of which articles A and A may be taken as examples, the preliminary operations comprise 'moving dead centers 41 to the proper longitudinal positions; positioning blowpipes B to heat the desired surface portions; adjusting the combustible mixture of gases, normally oxygen and acetylene, so that the heating flames will burn properly; adjusting timing mechanism 89 so that motor M will start, stop, reverse, and.

stop at desired predetermined time intervals; adlusting speed reducer 52 so that the articles A and A will be rotated at the desired speed, within limits, and so that gears 65 and 66 will rotate at the proper speed; and adjusting the circumferential positions of gears 65 and 66 so that pin 12 will .trip latch 66 and lever I6 will engage back bar 35 at the desired moments. The

backwardly through plate l6 to actuate a switch 92 (indicated by dotted lines in Fig. 6), switch 92 being utilized to start motor M when latch 68 is pushed backwardly by pin 12 against elongated stud Il. Lever I6 may be utilized in a similar manner to stop motor M, a suitable switch (not shown) being mounted above bearing 62 and having a switch actuating arm extending downwardly from above bearing 62 to a point at which the switch arm will be actuated by lever 16 as it begins to cause the work sup-.

port to pivot upwardly. Or, suitable stop-limit switches may be mounted on pedestal P to be actuated by one of brackets 30, so that when the carriage has traversed the desired distance, the stop-limit switches will operate to shut of! motor M, the motor being started by switch 92. Other variations of mechanism for starting and stop-- ping motor M are within the scope of this invention, and it will be further understood that various changes, other than those mentioned specifically, may be made which will not depart from the spirit and scope of this invention.

to reposition gear 65.for treatment of a different roup of articles.

With the above adjustments made, the first of a group of articles to be treated may be placedin either holder H or H depending on which is in the loading and unloading position. The heating gases are then turned on and the heating flames ignited, or, if a lighting "blowpipe is used, the pilot light ignited. Motor M is then startedby switch 85, and, just as pin 12 trips latch 68, motor M is started by switch 81 which starts timing mechanism 89 in operation. As-

suming that the first article was placed in holder I H, tripping of latch 68 and starting offmotor' M will cause the work support to pivot downwardly and travel to the left along stop S. When the carriage reaches the left position, motor M will stop and lever 16 engage bar 35.120 cause the work support to pivot upwardly. At the end of a predetermined time interval of heating, during which the second article is placed in holder- H', gear 65'will have rotated until pin 12 trips latch 68 tocause the work support to pivot downwardly. Simultaneously, motor M is started and the carriage C and work support W move to the right. During such movement, the heated surface portions of the first article are quenched and thereby hardened. When work support W and carriage C reach the right position, motor M is stopped and work support W caused to pivot upwardly, thereby placing the second article in heating position. During heating'of the second article, the first article, now treated, is replaced by the third article of the group, in holder H.

The sequence of operations is then repeated, as 7,

indicated previously. 7

It will be understoodv that a source-.or sources of high temperature heat other than'blowpipe flames may be used. Electrical heating means, such as an induction heating element, or any other suitable source of localized high tempera.

ture heat, may be utilized.

It will be further understood that various changes may be made in-theapparatus. For instance, in lieu of timing mechanism 89, a suit-- able switch for controlling motor may be mounted on carriage C and actuated y support W as it pivots on shaft 40. Again, stud ll may extend further outwardly from plate It and also From the foregoing description, it will be ap-- Parent that by use of the apparatus of this invention, selected surface portions ofeach of any group of a pluralityof similar or substantially identical articles canbe hardened quickly, eflec' tively, and efliciently. It will further be apparent that by use of the apparatus of this invention, the time required for positioning articles is reduced to a minimum, and the apparatus may readily be made sufliclently automatic so that the only manual operations required are the replacing of treated articles by untreated ones. What is claimed is: 1-Apparatus for heat treating in successio each article of a group of similar articles, such apparatus comprising movable means for supporting in spaced relationship two articles to be treated; means for heating selected surface por-' tions of said articles; means fon intermittently moving said supporting means between a position in which'one of said articles is disposed in operative relation with respect to saidheating means and the other of said articles is disposed at a point spaced from said heating means, and

' movement of said supporting means to a second position in which the latter article is disposed in operative relation with respect to said heating means and the former article is disposed at a point spaced from said heating means; and means for cooling the heated surface portions of .the former article during movement of said supporting means from said first position to said second position and for cooling the heated surface portion of the latter article during movement of said supporting means fromsaid second position to said first position.

2. Apparatus as defined in claim 1, in which said cooling means comprises a body of quenching liquid, and which includes means for moving said articles into said quenching liquid during and for moving said articles out of said quenching liquid at the termination of each intermittent movement of said supporting means.

3. Apparatus as defined in claim 1, in which said supporting means includes a mgvable carriage and a support for said articles pivotally mounted on said carriage.

4; Apparatus as definedin claim 1, in which i said cooling means includes a body of quenching liquid and said article supporting means includes a movable carriage and a support for sa d articles pivotally mounted on said carriage for movement of said articles into and out of said quenching liquid.

5. Apparatus as defined in claim 1, including means for automatically starting and stopping movement of said supporting means at predetermined time intervals. I

6; Apparatus for heat treating in succession a plurality of substantially identical articles wherein an article tobe treated is disposed in operative relation with respect to a source of high temperature heat and after heating is subjected to the action of a quenching medium, such ap- Daratus comprising, in combination, a horizontally movable carriage; means pivotal about a horizontal axis and mounted on said carriage for supporting two articles to be treated in horizontally spaced relationship; means for heating selected surface portions of said articles; means comprising a body of quenching liquid for cooling the heated surface portions of said articles with respect to said heating means and a second so as to harden the same; means for intermit- 'tently moving said carriage between a first position in which one of said articles is disposed in horizontal alignment with said heating means r and a second position in which the other of said articles is disposed in horizontal alignment with said heating means; and actuating means for causing said article supporting means to pivot means for rotating said articles; means comprising a body of quenching liquid for cooling the heated surface portions of said articles so as to harden the same; means for reciprocating said carriage from a first position in which one of said articles is disposed in horizontal alignment position in which the other of said articles is disposed in horizontal alignment with respect to said heating means; and actuating means for causing said article supporting means to pivot,

upwardly and downwardly at predetermined intervals, so as to place the article in horizontal alignment with said heating meansin operative position with respect to said heating means at the termination of each reciprocatory movement of said carriage and to lower the heated article into said quenching liquid at the beginning of the next reciprocatory movement of said carriage.

12. Apparatus as defined in claim l1,in which said supporting means includes a rotating center at one end of each article and a longitudinally movable center at the other end of each article.

13. Apparatus as defined in claim 11, including adjustable power means connected with said rotating means and said actuating means, whereby adjustment of said power means to change the the termination o movements of said carriage and to lower the h article into said quenching liquidjat the beginning of the next move ment of said carriage.

7. Apparatus as defined in claim 6, which includes means for arresting the downward motion of said supporting means so as to maintain the previously heated article substantially at a predetermined height in said quenching liquid during movement through said liquid.

8. Apparatus as defined in claim 6, in which said actuating means includes a latch for holding said supporting means in an upper position and means for tripping said latch.

9. Apparatus as defined in claim 6, in which said actuating means includes a latch for holding said article supporting means in an upper position, means for tripping said latch to cause a heated article to be lowered into said quenching liquid, and means for engaging said supporting means to cause said supporting means to pivot upwardly and thereby cause an article to be treated to be placed in position for heating.

10. Apparatus as defined in claim 6, in which said heating means is disposed centrally with respect to the limits of movement of said carriage, and which includes means for introducing fresh cooling liquid into said body of quenching liquid adjacent said heating means and means for withdrawing liquid from said body of quenching liquid adjacent points spaced from said heatspeed of rotation of said articles will effect a corresponding change in the time intervals at which said supporting means is caused to pivot upwardly and downwardly.

14. Apparatus for heat treating in succession a plurality of substantially identical articles, comprising a horizontally reciprocable carriage;

. a support pivotal about a horizontal axis and mounted on said carriage, said support including two sets of forwardly extending and horizontally spaced arms, each set having adjacent the ends thereof means for holding an article to be treated; means for heating selected surface p01- tions of said articles; means comprising a body of quenching liquid for cooling theheated surface portions of said articles so as to harden the' same; means for reciprocating said carriage between a first position in which one of said ar-. ticles is in horizontal alignment withs'aid heating means and the other of said articles is spaced from said heating means at one side thereof, and

a second position in which the other articleisin' port is in an upper position while an article is be-- ing heated, said support is caused to pivot downwardly substantially simultaneously with the beginning of movement of said support from one position to the other position so that the previously heated article'is immersed in the quenching liquid during such movement and' the heated surface portions thereof are thereby hardened, and said supporting means is caused to pivot upwardly as said movement terminates so that the treated article may be replaced by the next article to be treated.

15. Apparatus for heat treating in succession a plurality of substantially identical articles, wherein an article to be treated is mounted upon a support and moved into operative relation with respect'to a source of high temperature heat paratus comprising, in combination, a reciprocable carriage; means movably mounted on said carriage for supporting two articles to be treated in spaced relationship, said supporting means including a rotatable center engaging one end of each article, a longitudinally movable center engagingthe opposite end of each article, resilient means for forcing said last-named centers against said articles to hold said articles between said centers, and means for moving said last-named centers to release said articles from between said centers; means for heating selected surface portions of said articles; a body of quenching liquid for cooling the heated surface portions of said articles so as to harden the same; and means for alternately reciprocating said carriage and moving said supporting means so as to position one of said articles in operative relation with respect to said heating means and the other of said articles at' a point spaced from and at one side of said heating means, and then to positionthe other of said articles in operative relation with respect to said heating means and the previously heated article at a point spaced from and at'the other side of said heating means; said reciprocating and moving means being so constructed and v the other of said positions.

HARRY V. INSKEEP.

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