US2265849A

US2265849A - Heat treating apparatus

Info

Publication number: US2265849A
Application number: US349676A
Authority: US
Inventors: Marsh Kirtland
Original assignee: Aluminum Company of America
Current assignee: Howmet Aerospace Inc
Priority date: 1940-08-02
Filing date: 1940-08-02
Publication date: 1941-12-09
Anticipated expiration: 1958-12-09

Description

K. MARSH 2,265,849

HEAT TREATING APPARATUS Dec. 9, 1941.

Filed Aug 2, 1940 6 Shets-Sheet 1 INVENTOR. K irI/and Harsh ATTORNEY.

Dec. 9, 1941. K. MARSH I HEAT TREATING APPARATUS Filed Aug. 2, 1940 6 Sheets-Sheet 2 'INVENTOR. Kiri/and l'larsh BY WW Dec. 9, 1941. K. MARSH A HEAT TREATING APPARATUS Filed Aug. 2, 1940 6 sheets sheet 4 INVENTOR. /f iri land Mars/I jBY Dec. 9', 1941. K. MARSH 2,265,849

HEAT TREATING APPARATUS Filed Aug. 2, 1940 G'Sheets-Sheet' 5 4 zao===s 1 'i'ii'n V V III'IIIIIIIIIIIIIIIIII 1 INVENTCR. Kiri/and Marsh 6 Sheets-Sheet 6 INVENTOR. Kiri/and Marsh ATTORNE Dec. 9, 1941. K. MARSH HEAT TREATING APPARATUS Filed Aug. 2, 1940 Ill Patented Dec. 9, 1941 HEAT TREATING APPARATUS Kirtland Marsh, Pittsburgh, Pa., assignor to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Application August 2, 1940, Serial No. 349,676

(Cl. 26H) 16 Claims.

This invention relates to apparatus for heat treating metals and alloys. It pertains particularly to a system wherein apparatus is provided for handling, heating, quenching, and drying of metal which is to be subjected to a heat treatment process. It further relates to'combinations and sub-combinations of such apparatus.

The invention will be described with reference to the heat treatment of metal sheets of aluminum alloys though it is in no way confined thereto. Heat treating is defined for purposes of this invention as heating metal to a desired elevated temperature, holding the metal at that temperature for a prescribed length of time, and then rapidly quenching or cooling the metal in a fluid coolant. metal, accurate temperature control and uniformity of temperature throughout the furnace heating chamber are desired. Likewise, the ability to rapidly quench the metal after it has been subjected to the required amount of heating, without excessive loss of heat from the heat-.

-ing chamber, is desired. The invention, therefore, contemplates the provision of apparatus arquickly, and uniformly, and to quench the heated load of metal with great rapidity. While the apparatus of the invention is particularly adapted to the performance of the above defined heat treating process, it will appear upon a reading of this specification that the invention may be useful in such other material treating processes as annealing, drying, baking, soaking, and preheating of metal or other materials. In many of such processes apparatus of the character here described and claimed may find utility.

Heat treating furnaces employed prior to this invention are characterized by numerous disadvantages. For instance, it has been known to so position a furnace heating chamber and a load quenching tank as to require that the load of metal be immersed in the water of the quenching tank before it is moved into the heating chamber. Such an arrangement is undesirable because it requires additional input of heat to the load to evaporate the water clinging thereto af er it is drawn into the furnace chamber, and also because it results in a tendency for the, load to e non-uniformly heated. With some materals such as aluminum and its alloys the presence of water on the surfaces of the metal being heated may even result in staining or marking of the metal, which is of course undesirable, if not detrimental.

Prior efforts to construct a furnace arranged to In a furnace for heating the.

Noting the aforementioned disadvantages of A prior furnaces, the general object of this invention may be stated as the provision of a heat treating apparatus having a heating chamber spaced from a quenching tank a distance sulficient to permit supporting of a load therebetween, and having improved load handling apparatus associated therewith.

A further object of the invention is the provision of heat treating apparatus adapted to dry charging of a load of metal and yet adapted to rapid quenching thereof.

Another object is the provision of a tracksupported load carrier adapted for movement under a heating chamber and over a quenchin tank. It is also an object to provide suitable load hoisting means for lifting a load carrier into a heating chamber and for lowering it into a quenching tank.

80 Another object is the provision of a retractable (0 ticularly in combination with yieldable door sealload carrier track under a heating chamber arranged to permit the lifting of a load of material into a heating chamber and lowering thereof into a quenching tank.

Another object is the provision ofa slidable door for a bottom opening of a heating chamber. It is also "an object to provide door traversing means adapted to withdraw a door from under a heating chamber, and to return the same, paring means,

Another'object is the provision of a track-sup- I ported slldable door for the bottom of a heating chamber adapted to be traversed lengthwise of 4 the heating chamber to permit entry and removal heat treating apparatus.

ing, drying, and unloading of one or more loads of metal.

The invention also has: for an object the cooperative inter-relation of some or all of the aforementioned devices. It is particularly an object to provide a retractable load carrying track and a slidably removable door under the heating chamber of a heat treating apparatus having a quenching tank spaced therebelow a distance greater than the vertical height of a furnace load.

These and other objects will be appreciated more fully upon a reading of the following description of a preferred form of heat treating apparatus embodying the invention. The objects are to be taken either singly or in combination, and are to include such other advantages as are explained herein but not above particularly expressed.

In the drawings cation:

Fig. 1 is a plan view of the heat treating apparatus constituting the preferred embodiment of the invention, showing the load handling means, the heating chamber, the drying chamber, and other parts thereof;

Fig. 2 is a side elevation of the apparatus of Fig. 1 (to the same scale), showing in addition thereto the quenching tank and other parts thereof; 7

Fig. 3 is an enlarged plan view taken on the line IIIIII of Fig. "I and showing the heating forming part of this specifisuch loads may be supported on a load carrier in parallel spaced relation, the spacing between v sheets being preferably at least 1% inches from center to center. The above load specifications are setv forth merely as exemplary of the purposes to which the invention may be applied.

The preferred apparatus may be generally identified as an elevator type of furnace with a quenching tank directly under a heating chamher, but with sufllcient vertical height between the bottom of the heating chamber and the top of the quenching tank, at floor level, to permit a load of material of the character above described to be moved therebetween on an overhead roller track. One or more load carriers may be' employed with this apparatus to support loads of sheets of the character above dechamber and part of the load handling means shown generally in Fig. 1, a portion of the heating chamber .and hoisting means thereon being broken away to illustrate apparatus associated therewith;

Fig. 4 is a side elevation, with parts broken away, of that portion of the apparatus shown in Fig. 3 (to the same enlarged scale), showing in addition thereto the quenching tank and other parts thereof;

Fig. 5 is a plan of the door traverse mechanism, part of the load handling means, and part of the drying chamber shown generally in Fig. 1 (to the same enlarged scale), a portion of the I door being broken away to illustrate other parts of the apparatus;

Fig. 6 is a side elevation of that portion of the apparatus shown in Fig. 5 (to the same enlarged scale);

Fig. '7 is a vertical section taken on line VIIVII of Fig. 3 and showing the heating chamber, bottom door therefor, load handling means, and quenching tank (to the same enlarged scale), the door being shown in sealed and unsealed positions on opposite sides of the center line;

Fig. 8 is an enlarged detail and sectional view door sealing means, taken along the line XI-Xf of Fig. 8.

The furnace apparatus shown in the drawings was designed for the heat treatment of 6,000 pound loads of aluminum alloy sheet or plate made up of as many as 36 sheets, each 28 feet scribed, and a suitable track is preferably provided for movably supporting a load carrier under the heating chamber and for conveying a load carrier beyond the heating chamber to a drying chamber and back to a reloading-position. The apparatus is preferably provided with suitable load hoisting means for lifting a load carrier and load supported dependingly therefrom into the heating chamber, lowering it into the quenching tank, and again raising it to the track under the heating chamber. A slidably removable door is preferably provided at the bottom of the heating chamber, with suitable mechanisms for opening and closing the same. The track for supporting the load carrier under the heating chamber is preferably made retractable to permit free passage of a load carrier into the heating chamber and into the quenching tank. Turning now to the drawings, particularly to Figs. 1 and 2 thereof, the preferred form of heat treating apparatus will now be described.

Loading transfer To the left in Figs. 1 and 2 there is shown a loading transfer I manually or otherwise laterally movable on two transfer rails 2 between a position in alignment with a return load carrier track made up of rollers l (as in Fig. 1) and a position in alignment with a furnace heating chamber 5. This loading transfer I preferably consists of a frame fabricated from structural shapes and having longitudinal side members tied together by suitable lateral members. The loading transfer I is dependingly supported from the two transfer rails 2 by means. of overhead transfer rollers 0 at each corner thereof, the rails 2 being supported from the floor at-their ends by structural, rail supporting columns I.

, The longitudinal side members of loading transfer I each carry a longitudinally extending series of inwardlypresented track rollers l which form a load carrier track serving as an extension of the return load carrier track, above generally referred to. when in alignmenttherewith.

The track rollers I of loading transfer I are arranged for the support and e thereover of a load carrier ll (see also Figs. 3 and 4) which. consists of a frame similar in character to the frame of transfer I. It is made up of longitudinal side members tied together at their ends and at intermediate points with suitable lateral members. The longitudinal side members of load carrier l0 are shouldered as at ll (see Fig. 4) to fit the track made up of rollers I. Thus, load carrier Ill, through shouldered portions II, is adapted to ride on the track rollers 8 of the transfer I.

long and inches wide. The sheets forming It will be noted that load carrier II is proof. The eyes I2 are adapted to be engaged by suitable attaching means, associated with hoisting apparatus, for lifting of the load carrier III into the heating chamber 5 and lowering there of into a quenching tank I5 under chamber 5. Supported dependingly from load carrier I6 are a plurality of load hangers I3 arranged in a plurality of longitudinal rows and attached to Iongitudinal structural members (not shown) forming part of the load carrier I 0. Each hanger I3 comprises a depending rod, cable, or wire and a suitable clip, clamp, or wedging gripper adapted to engage the upper edge of a metal sheet or plate. The details of the hangers I3 are not here important since any of various known devices of this character may be employed for attaching the metal sheets to be heat treated to the load carrier II). By arranging hangers I3 in longitudinal rows a plurality of metal sheets may be hung from the load carrier II) in parallel spaced relation. A large'number of hangers I3 is employed to securely and uniformly support each sheet forming part of the load, since it is desirable to prevent sagging of the sheets during heat treatment and to keep one sheet from touching another as far as practicable.

In the practice of the invention a load carrier I0 is loaded with a plurality of sheets, by securing the same to hangers- I3, when the loading portions of a load carrier track comprised of retractable track rollers I4 under heating chamher 5 and delivery track rollers I6, the latter being supported by structural members I'I extending beyond the end of the heating chamber 5 opposite to loading transfer I. It will appear then that a load carrier III may be manually or otherwise moved from the loading transfer I onto the retractable track rollers I4, under the heating chamber 5.

Furnace apparatus heating chamber 5. The retractable rollers I4 and apparatus thereabove are located above'the floor level sumciently for the passage of a load to charging. position, the quenching tank I5 being directly below the heating chamber 5 but depressed below the floor level.

The heating chamber 5 is provided with door 20 for the receipt and discharge of the load through the bottom thereof, door 20 being removable from under the heating chamber 5 by horizontal sliding movement to the right, as

. viewed in Figs. 1. and 2, where it is shownin open position. For supporting the door during opening and closing movements, there is provided'a door track 23 formed of angles at either longitudinal side of heating chamber 5 and extending beyond the same at one end as above described.

An operating cylinder 2| and mechanism associated therewith, which will be described later, are employed for effecting the movement of door 20 on tracks 23. provided on each side of heating chamber 5 for actuating a door locking means, which will also be later described, adapted to seal the door against the bottom of the heating chamber 5. The aforementioned angles forming track23 support the door 26 during its horizontal movement at positions above a load carrier III and track rollers I4 and I6 for supporting a load carrier III.

The retractable track rollers I4 are mounted on two longitudinally extending structural members 25 (see Fig. 3), each of which is retractable to the side of the heating chamber 5 through the actuation of an operating cylinder 26 and mechanism associated therewith. This mechanism, to be later described in detail, is arranged to move the structural members 25 into and out of projected operative position. Fig. 3 shows structural members 25, carrying track rollers I4 in projected position.

As aforementioned, the quenching tank I5 is located beneath the floor level and below the heating chamber 5. It is of conventional construction and deep enough to accommodate a full load of maximum size sheets along with a load carrier I0 which supports the same (as in Figs. 2 and 4). The usual spill drain 28 is provided at the upper portion of the quenching tank I5.

The heating chamber 5 is preferably heated by electric resistance heaters in conventional fashion. Surmounting the chamber 5 are six furnace blowers 29 for the forced circulation of the furnace atmosphere. heating and circulating the furnace atmosphere are not important to the present invention, and will not be further described. Also, surmounting the heating chamber 5 there is provided a hoist frame 30 supporting a load hoist mechanism.

The hoist mechanism comprises eight hoisting cables 3| passing downwardly through the roof of the heating chamber 5 to a pair of interto the top of hoist frame 36. They each pass I around two

pulleys

34 and 35, the fixed pulleys '35" being suitably mounted on the base of hoist frame 36. The movable pulleys 34 are mounted on a movable carriage 36 sothat they may be moved to the left or right (as viewed in Figs. 2 and 4) to, in effect, shorten or lengthen the hoisting cables 3I. Carriage 36 is a fabricated structure supported by rollers 43 at the sides thereof (see Fig. 3) adapted to ride in guide rails 4| mounted on hoist frame 30. Forward position of carriage 36 is limited by a stop 42 (see Fig. 4), and rearward position thereof is limited by the upward position of load lift beam 32 in heating chamber 5, or by the stroke of the hoist operating cylinder 38. The carriage 36 is secured to the piston rod 31 of operating cylinder 36, by

actuation of which the load lift beam 32 may be raised or lowered as is desired. in a known manner. Associated with the piston rod 31 and cylinder 38 there is provided a latch 39 to lock the hoisting apparatus when the load is within the heating chamber 5 so as to prevent accidental release thereof before retractable rollers I4 are retracted. The details of this latch 39 are not An operating cylinder 22 is The details of apparatus for a essential to the invention, and will not be further described.

At the lower extremities of the hoist cables 3I on either side of the heating chamber 5 are secured, through suitable connecting links, the two longitudinally extending portions of the load lift beam 32 which may be, as is shown in Fig. 4, made up of a plurality of hingedly related beam sections disposed on opposite interior sides of the heating chamber 5, tied together by suitable cross members. The load lift beam 32 is, in effect, one simple frame but is constructed for slight hinged relation of the aforementioned sections to make it more easily attached to the load carrier III, and to allow for variable heat expansion thereof. Depending from the load lift beam 32 along each longitudinal side portion thereof are a plurality of hooks 48 adapted to be engaged with the eyes I2 on a load carrier III. A load carrier I8 is engaged with the load lift beam 32 by moving the load carrier on track rollers I4 a few inches beyond registering position with the load lift beam, then lowering the load lift beam. so

that the hooks 40 are opposite the eyes I2, and then slightly moving the load carrier to place the eyes I2 over the hooks 40. Thereupon, the load lift beam 32 may be raised by the hoisting mechanism, actuated by the operating cylinder 38, to lift the load carrier I and load supported thereby. In this manner the load carrier I0 may be removed from its support on retractable track rollers I4. When it is desired to re-deposit the load carrier III upon the rollers I4, and dis engage the load lift beam 32 from the load carrier III, the reverse of the above described procedure may be employed.

Drying apparatus Leaving for later discussion further details of the apparatus associated with the heating chamber and quenching tank- I5, it is pointed out that a load carrier III will be removed from under the heating chamber 5 by passage along the retractable track rollers I4 over onto the delivery .track rollers I5. The load will be moved furbers carrying the inwardly presented track rollers 45. It is dependingly supported by overhead transfer rollers 41 on three transfer rails 48 for movement'from a position in alignment with the track formed by rollers I8 to a position in alignment with the aforementioned return track rollers 4. The transfer rails 48 are supported by suitable structural rail supporting columns 44. The lateral transferring motion of drying transfer 45 may be imparted manually or by suitable mechanical means. Further associated with the drying transfer 45 is a U-shaped enclosing shell, having a partial top and no bottom, and having an open end for receipt and delivery of the load. The loading transfer, midway of its motion between the position in alignment with the track rollers I8 and the position in alignment with track rollers 4, is adapted to be stopped and located under a drying apparatus 58 mounted on transfer rails 48, so that the drying apparatus 58 and transfer 45, in cooperation with the floor, form a. drying chamber open only, if desired, at the left end (as viewed in Figs. 1

aperture 43 is provided in the partial top of dryapparatus 58. The drying apparatus 50 comprises suitably arranged blowers 5| adapted to blow air through electric or steam heaters, and through. aperture 48 into drying transfer 45, to circulate heated air through the load for evaporating the quench water therefrom.

On completion of the drying operation a load carrier III on drying transfer 45 is adapted to be placed in alignment with return track rollers 4 and delivered therealong over to the loading transfer I. The return track rollers 4 form a return load carrier track, the rollers 4 being mounted in structural members 54, supported from the floor by structural columns 55. Thus, it will be seen that the loading transfer I, track made up of rollers I4 and I5, drying transfer 46, and return track made up of rollers 4 provide a load circulating track system capable of accommodating 'several load carriers I8. Load carriers are shown in various positions in the drawings for clarity in description. The load carriers may be unloaded and reloaded at any desired position along this track system. The preferred loading position is at the loading transfer I, and the preferred unloading positions are along return track rollers 4.

Retractable track The retractable track will now be particularlydescribed with reference to Figs. 3, 4, '7, 8, and 10. Description of the retractable track made up of rollers I4 and structural members 25 will be confined to that portion thereof located on one side of the heating chamber 5, which will exemplify the operation of the retractable track as a whole. It will be noted that the track rollers I4 are pin supported in longitudinally-extending structural members 25, being secured thereto by nuts 24 (see Figs. 8 and 10). The structural members 25 extend throughout the length of the heating chamber 5 and are secured by T connections to horizontally disposed rack members 50, perpendicular thereto. The rack members 58 are fabricated structural members made up of two back-to-back channels having secured therebetween, by bolts 51, and facing downwardly, a rack portion 5|. Each rack member 50 is supported indirectly by structural heating chamber columns I8 through the medium of a pair of lower fulcrum rollers 52 and a pair of upper fulcrum rollers 58. The rollers 52 are placed over a pin 53 mounted in a bracket secured by bolts 55 on an angle 55 connecting interiorly with and across the structural columns I8. These lower fulcrum rollers 82 support the rack member 58 on the side of the structural columns I8 facing the interior of the heating chamber 5. Similar upper fulcrum rollers 58 are placed over a pin 59 mounted in a bracket 18 secured by bolts 12 on an angle 'II- connecting exteriorly with and across the structural columns I8. They support the outer end of each rack member 58 I8. The cylinder 25 has a piston rod 13 suitably and 2). An

connected to a rack I4 in engagement with a pinion I5. The pinion I5 is mounted on a shaft I8 extending the length of the heating chamber 5. Shaft ,18 is supported in bearing brackets 'I'I secured by bolts 82 on an angle 18 connecting structural columns I8. The rack 14 is held against the pinion 15 by a suitable backing roller I8 opposite thereto suitably mounted and supported. Operation of the piston rod I3 causes the rack 14 to impart rotary movement through the pinion I to the shaft 18. Spaced opposite each rack member 88 is a suitably keyed pinion 88 on shaft 16 which engages the rack portion 8| of each rack member 88. Thus, rotation of shaft I8 imparts rotation to pinions 88 and thereby efiects inward and outward movement of each rack member 88. Two cylinders 28, one at each side of the furnace, through the aforementioned linkages, are efiective to commonly actuate all of the rack members 68 so as to project or retract the retractable track formed by rollers I4 at the desired times. The mechanism here described is duplicated on both sides of the furnace apparatus, and thus, the simultaneous operation or substantially simultaneous operation of two operating cylinders 28 is effective to project the rollers I4 so as to form a load carrier track, or to retract the same for the vertical raising or lowering therebetween of the load carrier I8 and load supported thereby.

Door operating mechanisms 30 members forming a hollow frame that is filled with suitable insulating material, and is adapted for closing off the opening in the bottom of the heating chamber 5 and sealing the same. To effect the sealing action a-suitable gasket'l8 is provided around the upper edges of'door 28 so 40 that sealing pressure on the bottom of the door 28 may yieldably sealthe door 28 against, the bottom of the heating chamber 5. The longitudinal sides of the door 28' are provided with shouldered recesses 85 (see Fig. 8) containing yieldably mounted spring holders 88. Each spring holder 88 is pivotally secured on a pin 88 to a bracket 81. (see Fig. 11) attached to the door 28 in one of the two shouldered recesses 85. Each spring holder 88, at the other end thereof, is provided witlna cylindrical socket 88 adapted to receive an adjustably compressible spring 88. The spring is held in socket 88 by means of a bolt 8| passing through the lower end of socket 88 and by a washer 82 and nut 88 at the top thereof, these means being arranged to confine the spring between the washer 82 and the bottom of socket 88. The upper end of bolt 8| is adapted to bear against a recess 88- of door 28. The socket 88 of each spring holder 88 is provided with a lug or ear 88 through which a bolt 85 loosely passes. The bolt 85 is carried by the door frame and has adjusting nut 81 and locking nut 88, whereby the spring holder 88 may be adjustably positioned with respect to the door 05 frame. When the spring holders are moved upwardly, the spring pressed bolts 8| engage the bottom of the door frame, and the door 28 is raised thereby to sealing position under a pres sure determined by the pressure of the springs 88. The length and load of each spring 88 may be suitably adjusted by tightening or loosening the nut 88 on bolt 8I. Thus, it will appear that pressure upwardly exerted on each spring holder 88 will be adapted to yieldably and releasably 7 seal door 28 and gasket l8 against the bottom of heating chamber 8.

As aforementioned, there are a plurality of spring holders 86 secured, as above described, along the shouldered recesses on either side of door 28. A plurality of roller clamps I88 are adapted to press against the spring holders 88 to raise the door 28 into sealing position. These roller clamps I88 take the form of cranks, secured to stub shafts I8l that extend crosswise of the furnace from immediately under the longitudinal edges of the door 28 to the outside of the frame work of the apparatus. The roller clamps I88 extend normally parallel to spring holders 88 and are provided with pin supported clamping rollers I82 adaptedto bear against the spring holders 88. The shafts I8I are mounted in suitable bearings in brackets I88 dependingly supportedfrom door track angles 23 and angles 'II above mentioned.

' On the outer end of each shaft I8I there is secured a crank lever I84. Each of the crank levers I84, along the length of each side of the furnace,- is connected by suitable clevis and pin. The opera" connection to an operating rod I85. ating rods I85, at the end of the heating chamber 5 adjacent the loading transfer I, are connected by links I 88 to bell cranks I8'I rotatably mounted on pins supported in brackets I88 (see Fig. 3) secured to structural columns 'I'8. The other ends of bell cranks I8'I are secured to piston rods I88 of the operating cylinders 22.

Thus, it will appear that motion of a piston rod I88 will impart rotary movement to a bell crank I81 which, through a link I88, will move 'an operating rod I85 lengthwise of the heating 45 the door 28. The springs 88 are adapted to permit the necessary amount of overtravel inherent in the use of a plurality of commonly actuated roller clamps I88, and furthermore, by their adjustability are adapted to exert a predetermined sealing pressure on the door 28. The

pressure exerted by each roller clamp I88 on the door 28 through each spr ng holder 88 will be determined by the amount of precompression of each spring 88 attained through the adjustment of each nut 88.

What has been just described is the actuating mechanism for vertically moving the door into and out of sealing position. In its lower open position, the door is supported on the heretofore mentioned track 28' by means of a series of rollersll8 disposed along each lateral edge of the door, as best seen in Figs. 7 and 8. The track rails 23 are secured to the lower flanges of channels III that are secured to the under side of the furnace structure. The door also is provided with guide rollers II8 that are joumalled on vertical axes for engagement with the webs of the channels III during travel of the door on the track 28.

Referring now in particular to Figs. 5 and 6, the mechanism which may be employed for removing the door 28 from beneath the heating chamber 8 and returning the same will be described. The door 28 is arranged to be traversed on the track 28 beneath the heating chamber 8 a direction.

over onto an extension of track 23 formed by similar angles supported'upon structural members II4, which portion of track 23 extends beyond the heating chamber on the end opposite to the loading transfer I. In these figures, the door is shown so removed from under the heating chamber 5 and resting upon the extended track 23.

The traversing longitudinal movement of door 20 between its position under the heating chamber 5 and the position shown in Figs. 5 and 6 is effected by means of pairs of traversing cables I I5 and I I5a, respectively, passed over pulleys I I6 secured to the base of heating chamber 5 and over pulleys II'I secured to cross pieces II8 mounted upon transfer rails 48 adjacent the drying apparatus 50. Each end of the upper strands of cables H5 and II5a is secured in multiple wraps over one of four driving drums or pulleys H9, the wrappings of the respective pairs of cables on their drums "II! being effected in opposite directions. Each end of the lower strands of cables I I5 and I I5a is secured, through a suitable adjustable anchor connection I20 to a bracket extension I22 of the door 20 provided at the end thereof nearest the drying apparatus 50. Thus, it will appear that rotation of the driving drums I I9 in one direction will efl'ect winding of the cables of one pair and unwinding of the cables of the other pair upon their respective drums. whereby the door is moved longitudinally in one Rotation of the drums in the opposite direction will effect travel of the door in the opposite direction.

The driving pulleys II! are suitably keyed to a common shaft I24 mounted in bearing brackets I25. mounted on cross members I21 supported by the aforementioned structural columns II4. A pair of channels I25, likewise supported on cross members I21, supports the operating cylinder 2I. This cylinder is disposed with its axis parallel to the longitudinal direction of motion of the door 20 and has a piston rod I30 secured to a rack I3I, the latter meshing with a pinion I34 mounted centrally of the shaft I24. For holdin the rack I3I against the pinion I34 an overhead backing or guide roller I35 is provided opposite the pinion I34, which guide roller I35 is secured in suitable retaining members I35. The end of the rack I3I is provided with a supporting roller I30 adapted to ride on a rail I39 mounted at one end on a beam I26 and extending over to a cross member I40 supported adjacent the drying apparatus 50. Cross member 0' is mounted on cross pieces II8 bridging transfer rails 43. From the foregoing description, it will appear that motion of the rack I3I imparted by operating pressure from cylinder 2I may be employed for rotating drive pulleys Ill and traversing the door 20 to and from its position beneath the heating chamber 5.

Operation The preferred mode ofoperation of the heat treating apparatus herein described may be most Brackets I25 are secured to beams I25 paratus, as shown in Fig. I, and that there is a load of material in unloading position supported crating cylinder from a third load carrier I0 on the return track formed by rollers 4.

The load carrier I0 on loading transfer I will be in the process of being loaded with sheets to be heat treated, these sheets being secured to the load hangers I3 depending from the load carrier I0. Likewise, at-the same time, the load carrier I0 which is in unloading position on the return track may be in the process of being unloaded by removal of the metal sheets from the load hangers I3, which support the same. These loading and unloading operations will take place during the period of heat treatment including heating and quenching, if desired, of still another load in the furnace heating chamber 5 or in the quenching tank I5. Thus, a new load of material will be ready for entry into the heating chamber 5 as soon as the preceding load is removed from the furnace or the quenching tank, and an unloaded carrier I0 will be ready to be loaded immediately following the loading operation on the previous load carrier I0.

It is further assumed that the furnace door 20 is under the heating chamber 5 and sealed thereagainst. After the load in the heating chamber 5 has been raised to a heat treating temperature and retained at such temperature for the desired length of time, the following steps will be carried out. The retractable rollers I4 beneath the heating chamber 5 will be retracted to the sides of the heating chamber 5 by the operation of the operating cylinders 25 associated therewith. When the load track formed by retractable rollers I4 has been retracted, the door 20 will be moved to unseal thesame from the heating chamber 5. To perform this operation, the operating cylinder 22 will be actuated to release and lower the door sealing roller clamps I00. 'Release of the roller clamps I00 will permit the door 20 to move downward until its rollers IIO engage the door track 23. 'Thereupon, the door 20 will be withdrawn from beneath the heating chamber 5 by actuation of the operating cylinder 2I, exerting a pulling force through the traversing-cables II5a. Thus, the door will be released and removed from beneath the heating The load lift beam 32 i adapted to support the load carrier I0 and load dependingly hung therefrom in the quenching tank I5 for the desired quenching period. In cases where it may be desirable to do so, the load lift beam 32 may be disengaged from the load carrier I0 when it is in, or immediately above, the quenching tank I5. However, this is not the preferred cycle of operations. Such deviation from the preferred cycle of operations would probably require the provision of a load carrier rest in the quenching tank similar to the retractable rollers I4 adapted to support the load carrier I0 between the heating chamber 5 and the quenching tank I5.

When it is desired to raise the load out of the quenching, tank I5, the hoisting cables II will again be raised by the operation of the op- 33. The lifting operation undertaken by the hoisting cables 3| will be discontinued when the load carrier I is disposed slightly above the level of the retractable rollers I4. Thereupon, the retractable rollers I will be projected into their inward positions by the operation of operating cylinder 26, so that the rollers M will be in position under the load carrier Hi to support the same. Thereupon, the load carrier I will be deposited upon the retractable rollers M by slight lowering of the hoisting cables 3| through actuation of the operating cylinder 38. Following the depositing of the load carrier 10 on the retractable rollers M, the hoisting cables will preferably be lowered a little so as to permit disengagement of the hooks 40 on load lift beam 32'from the eyes [2 of the load carrier I0. Thereupon, disengagement of hooks 40 and eyes 12 will be effected by slight horizontal motion of the load carrier ID with reference to the loadlift beam 32. Upon disengagement of the load lift beam 32 from the load carrier II), as described, the load lift beam 32 will preferably be raised slightly above the load carrier It so as to permit the free passage of load carrier l0 over the rollers l4 and beyond the heating chamber 5 onto the rollers l6 forming a delivery track. The load will be moved over to the rollers l6 manually or by suitable-mechanical devices.

If it is desired, the load lift beam 32 may be fully retracted within the heating chamber 5 to permit closing of the heating chamber by traversing the door 20 thereunder and sealing the same thereagainst. This may be desirable if there is to be appreciable time between the removal of one load and the insertion of another load.

As soon as the load, which has been above described, has been moved over onto rollers IS, the new load which has been secured to the load carrier II) on loading transfer I will be moved from the loading transfer I onto the retractable rollers l4 under the heating chamber 5. If the door 20 has been closed, it will be opened to permit receipt of the newly placed load carrier I0. Assuming the door to be open,- the load carrier III will be raised into the heating chamber 5 upon the performance of the following operations. The load lift beam will be lowered, throughoperation of the hoisting cables 3| and operating cylinder 38, so that the hooks 40 are again opposite eyes l2 of the load carrier Ill. Thereupon, the load carrier ID will be engaged with the hooks of the load lift beam 32, and the load lift beam 32 and loadcarrier III will be raised into .the heating chamber 5,through op- Upon the sealing of the door 20, the heating portion of the heat treating process will be instituted, and upon its completion, the cycle of operations which has been hereinabove described will be again carried out with reference to the load within the heating chamber 5. At this time, the load carrier l0, which has been in unloading position on the delivery track 4, will be delivered onto the loading transfer I and there loaded.

The load carrier which was moved out onto delivery rollers IG will be preferably immediately moved onto the rollers 45 of the drying transfer.

drying transfer 46 will preferably be moved laterally into alignment with the return track rollers 4. Thereupon, the load carrier III will be convenient loading and unloading of material to be subjected to a heat treating process, and that it permits rapid entry of the material into the heating chamber and rapid delivery of the material from the heatingchamber to the quenching tank. It will further appear that it presents an organization of apparatus particularly well adapted to the dry charging of a load into the heating chamber and to the rapid quenching thereof, as well as to the-rapid removal and disposition thereof both in a drying chamber and to an unloading P sition, and that the several operations of the entire system can be carried out substantially concurrently.

While the invention has been described with reference to its adaptability to handle loads of metal to be heat treated, particularly loads made up of metal sheets, it will appear that it is adapted to the handling of other types of loads, and that the apparatus may be useful in the performance of other metal treating processes, or to the performance of processes on other materials.

Numerous modifications may be made in the mechanical structure of the apparatus described.

eration of the operatingcylinder 38 and hoisting cables 3|. The lifting of the load into the heating chamber may be temporarily interrupted after partial lifting of the load carrier lfl-to permit retraction of retractable'rollers It in order to prevent any interference of the load thereof with load carrier l0 and its load as it passes into the load chamber 5. The retraction of the rollers 14 at this time, it is noted, does away with the necessity of retracting the same when it is desired to lower the load-from the heating chamber 5 into the quenching tank l5.

When the load lift beam 32 has been raised to carry the load carrier l0 into proper position within the heating chamber 5, the door- 20 will be traversed under the heating chamber 5 by operation of the operating cylinder 2|. It will then be raised into sealing position by the operation of the operating cylinders 22, as above described.

paratus have been only generally referred to since their design will become apparent to those skilled in the art upon the reading of this speci- Y flcation. The invention is therefore set forth in the appended claims with the intent that they be read broadly in the light of the objects of this invention, and with only such limitations as are imposed by the prior art. f

What is claimed is:

1. In combination with a furnace having a heating chamber, a bottom door for said cham-; her, a tank located below said chamber a distance greater than the load height thereof, means for supporting a furnace load between said chamber and said tank, said load supporting means being retractable from supporting positron, and means for liftinga furnace load from said load supporting means into said chamber, said lifting means being adapted to lower the lifted load into said tank when said load supporting means are retracted. I

zontal delivery therealong of a furnace load, said load supporting track being retractable toward at least one side of said chamber, and means for lifting a 'furnace load from said load supporting track into said chamber, said lifting means being adapted to lower the lifted load into said tank when said load supporting track is retracted.

3. In combination with a furnace having a heating chamber, a bottom door for said chamber, a tank located below said chamber a distance greater than the load height thereof, a load supporting track beneath said door for horizontal delivery therealong of a furnace load, said load supporting track being retractable toward at least one side of said chamber, hoist means for raising, lowering, and holding a furnace load between and at positions in said chamber, in said movable door adapted to be upwardly sealed against the bottom of said chamber, yieldable means for releasably pressing said door into sealing position, means beneath said chamber and extending beyond at least one end thereof for supporting said door for horizontal opening and closing movement when released, means for moving said door along said door supporting tank, and on said load supporting track, and 1 means for retracting said load supporting track to permit raising or lowering of a furnace load and for projecting the same to receive and support a furnace load.

4. In combination with a furnace having a heating chamber, a horizontally movable bottom door for said chamber, means for opening and closing said door by sliding movement, a tank located below said chamber a distance greater than the load height thereof, means for supporting a furnace load between said chamber and said tank, said load supporting means being retractable from supporting position, and means for lifting a furnace load from said load supporting means into said chamber, said lifting means being adapted to lower the lifted load into said tank when said load supporting means are retracted.

5. In combination with a furnace having a heating chamber, a horizontally movable bottom door for said chamber, means for opening and closing said door by sliding movement, a tank located below said. chamber a distance greater than the load height thereof, a load supporting track beneath said door for horizontal delivery therealong of afurnace load, said load supporting track being retractable toward at least one side of said chamber, and means for lifting a furnace load from said load supporting track into said chamber, said lifting means being adapted to lower the lifted load into said tank when said load supporting track is retracted.

6. In combination with a furnace having a heating chamber, a horizontally movable bottom door for said chamber, means for opening and closing said door by sliding-movement, a tank located below said chamber a distance greater than the load height thereof, a load supporting track beneath said'door for horizontal delivery therealong of a furnace load, said load supporting track being retractable toward at least one side of said chamber, hoist means for raising, lowering, and holding a furnace load between ing beyond at least one end thereof for support-- a ing said door for horizontal opening and closing means, a quenching tank located below said chamber a distance greater than the load height thereof, means for supporting a furnace load between said chamber and said tank, said load 'supporting means being retractable from supporting position, and means for lifting a furnace load from said load supporting means into 'said chamber, said lifting means being adapted to lower the lifted load into said tank when said load supporting means are retracted.

8. In combination with a heat treating furnace having a heating chamber, a horizontally movable door adapted to be upwardly sealed against the bottom of said chamber, yieldable means for releasably pressing said door into sealing position, means beneath said chamber and extending beyond at least one end thereof for supporting said door for horizontal opening and closing movement when released, means for moving said .door along said door supporting means, a quenching tank located below said chamber a distance greater than the load height thereof, a load supporting track beneath said door for horizontal delivery therealong of a furnace load, said load supporting track being retractable toward at least one side of said chamber, and means for lifting a furnace load from said load supporting track into said chamber, said lifting means being adapted to lower the lifted load into said tank when said load sup porting track is retracted.

9. In combination with a heat treating furnace having a' heating chamber, a horizontally movable door adapted to be upwardly sealed against the bottom of said chamber, yieldable means for releasably pressing said door into sealing position, means beneath said chamber and extendmovement when released, means for moving said door along said door supporting means, a'

quenching -tank located below said chamber a distance greater than the load height thereof, a

- load supporting track beneath said door for horiand at positions in said chamber, in said tank,

zontal delivery therealong of a furnace load, said load supporting track being retractable toward at least one side of said chamber, hoist means for raising, lowering, and holding a furnace load between and at positions in said chamber, in said tank, and on said load supporting track, and means for retracting said load supporting track to permit raising or lowering of' a furnace load and for projecting the same to receive and support a furnace load. 4

10. A heat treating apparatus comprising a heating chamber elevated above floor level, a

' quenching tank under. said chamber but depressed below floor level, said chamber and said tank being vertically separated a distance greater than the load height of saidchamber to provide therebetween a loading space at and above floor level, a load carrier track extending through said loading space for movably'supporting a load carrier, a load carrier adapted to move along said load carrier track and to carry a furnace load of metal sheets dependingly hung therefrom, a door in the bottom of said heating chamber adapted to be opened and closed for the receipt and discharge of a load carrier, hoisting means withdrawable into said chamber and extendable into said tank, means for attaching said hoisting means to said load carrier, and means for retracting at least that portion of said load carrier track which is directly under said chamber to at least one side of said chamber after engagement of said hoisting meanswith said load carrier, said retracting means being adapted to subsequently project said portion of said load carrier track to load supporting position, whereby the load carrier and its load maybe withdrawn into said chamber, lowered into said tank, and returned to said load carrier track by said hoisting means, and whereby said load carrier track provides delivery and removal means for said load carrier.

11. A heat treating apparatus comprising a heating chamber elevated above floor level, a

quenching tank under said chamber but depressed below floor level, said chamber and said tank being vertically separated a distance greater than the load height of said chamber to provide therebetween a loading space at and above floor level, a load 'carriertrack extending through 'said loading space for movably supporting a load carrier, a load carrier adapted to move along said load carrier track and to carry a furnace load of metal sheets dependingly hung therefrom, a door in the bottom of said heating chamber adapted to be opened and closed for the receipt and discharge of a load carrier, yieldable means for releasably pressing said door upwardly against the bottom of said chamber and into sealing engagementv therewith, a door supporting track above said load carrier track extending under said door and beyond one-end of said chamber, means for horizontally moving. said door when released onto said door supporting track to and from a position under said chamber, hoist means for raising, lowering, and holding a furnace load between and at positions in said chamber, in said tank, and on said load carrier track, and means for retracting said load supporting track to permitraising or lowering of a. furnace load and for projecting the same to receive and support a furnace load.

12. A heat treating apparatus comprising a. heating chamber elevated above floor level, a quenching tank under said chamber but depressed below floor level,said chamber and said tank being vertically separated a distance greater than the load height of said chamber to provide therebetween a loading space at and above floor level, a load carrier track extending through said loading space for movably supporting a load carrier, a return load carrier track along one side of said heating chamber and substantially parallel to said first mentioned load carrier track, transfer tracks. movable for alignment with either of said load carrier tracks at each end thereof for transferring a load carrier from one to the other of said load carrier tracks, a load carrier adapted to move along said load carrier track and to carry a furnace load of metal sheets dependingly hung therefrom, a door inthe bottom of said heating chamber adapted to be opened and closed for the receipt and discharge of a load carrier, hoisting means withdrawable into said chamber and extendable into said tank, means for attaching said hoisting means to said load carrier, and means for retracting at least that portion of said load carrier track which is of said chamber after engagement of said hoisting, means with said load carrier, said retracting means being adapted to subsequently project said portion of said load carrier track to load supporting position, whereby the load carrier and its load may be withdrawn into said chamber, lowered into said tank, and returned to said load carrier track by said hoisting means, and whereby said load carrier tracks provide a circulatory load delivery and removal system.' 7

13. A heat treating apparatus comprising a heating chamber elevated above floor level, a quenching tank under said chamber but depressed below floor level, said chamber and said tank being vertically separated a distance greater than the load height of said chamber to provide thereing a flow of heated air through said drying receipt and discharge of a load carrier, hoisting chamber to evaporate clinging quench water from a furnace load carried by a load carrier on said transfer track, a load carrier adapted to move along said load carrier track and to carry a furnace load of metal sheets dependingly hung therefrom, a door in the bottom of said heating chamber adapted to be opened and closed for the means withdrawable into said chamber and extendable into said tank, means for attaching said hoisting means to said load carrier, arid means for retracting at least that portion of said load carrier track which is directly under said chamber to at least one side of said chamber after engagement of said hoisting means with said load carrier, said retracting means being adapted to subsequently project said portion of said load carrier trackto load supporting position, whereby .the load carrier and its load may be withdrawn into said chamber, lowered into said tank, and'returned to said load carrier track by said hoisting means, and whereby said load carrier tracks provide a circulatory load delivery and removal system.

directly under said chamber to at least one side 14. In a heat treating system of the type described, the combination comprising an elevated track structure, a plurality of carriers movable along said track and adapted for upward movement with respect thereto, a portion of said track being laterally retractable for movement of a carrier below the plane of said track, a heating chamber above said portion of said track, a tank spaced below said heating chamber a distance greater than the load height thereof to permit movement -of a loaded carrier therebetween, means engageable with-said loaded carrier be neath said chamber for raising the same into said heating chamber and for lowering the same into said tank, means for actuating said retractable portion of said track when the loaded carrier is disposed above or below the plane of said track, a bottom closure for said chamber, and means for actuating said closure for entry and discharge of said loaded carrier into and out of said chamber.

15. In a heat treating system of the type described, the combination comprising an elevated track structure, a plurality of carriers movable along said track and adapted for upward movement with respect thereto, a portion of said track A being laterally retractable for movement of a carrier below the plane of said track, a heating chamber above said portion of said track, a tank spaced below said heating chamber a distance greater than the load height thereof to permit movement of a loaded carrier 'therebetween, means engageable with said loaded carrier beneath said chamber for raising the same into said heating chamber and for lowering the same into said tank, means for actuating said retract able portion of said track when the loaded carrier is disposed above or below the plane of said track, a bottom closure for said chamber, and means for actuating said closure for entry and discharge of 'said loaded carrier into and out of said chamber, said track structure being arranged to accommodate said plurality of carriers simultaneously at a loading station, at an unloading station, and at a. treating station located at said heating chamber for movement through a path extending from each of said stations to the next station.

16. A heating. treating mechanism comprising in combination, a heating chamber disposed and aligned above a quenching tank, a track extending between chargingand discharging stations at opposite ends of the heating chamber, said track lying in a plane directly below the heating chamber and above the quenching tank, a second track in the same plane but spaced from and parallel to the first-mentioned track, at'least one carriage adapted to be translated along said tracks, cross rails adjacent the charging and discharging stations for connecting the parallel tracks, whereby a carriage may be laterally shunted from one to the other of the parallel tracks, means for hoisting and lowering a carriage from the track immediately below the heating chamber, a section of said last-mentioned track being adapted to be spread sufliciently to permit lowering a carriage through the same into the quenching tank, and said parallel track arrangement providing storage for a number of carriages.

KIRTLAND MARSH.