US1936719A

US1936719A - Apparatus for and method of heat treating metal

Info

Publication number: US1936719A
Application number: US399753A
Authority: US
Inventors: Horace C Knerr
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-10-15
Filing date: 1929-10-15
Publication date: 1933-11-28
Anticipated expiration: 1950-11-28

Description

NOV. 28, 1933. Q KNERR 1,936,719

APPARATUS FOR AND METHOD OF HEAT TREATING METAL I Filed Oct. 15, 1929 2 Sheets-Sheet l IIIIIII III Nov. 28, 1933.

H. c. KNERR APPARATUS FOR AND METHOD OF HEAT TREATING METAL Filed Oct. 15, 1929 2 Sheets-Sheet 2 MM dHIo-z "e1 Patented Nov. 28, 1933 UNITED STATES PATENT OFFICE APPARATUS FOR AND METHOD OF HEAT TREATING METAL 23 Claims.

My invention relates to apparatus which is adapted for use in the heat treatment of metals and the novel method involved in such treatment.

While the apparatus may be employed for the heat treatment of metal parts of all kinds and variety of shapes, yet it is particularly well adapted for the treatment of, parts which may be employed in aeroplane construction, many of which are of great length compared with their thickness or diameter.

The general object of the invention is to provide both a novel apparatus and a novel method for the heat treatment of metal parts in a manner to prevent distortion thereof and also in such a manner that a uniform and even-application of heat thereto is effected.

It also is an object of the invention to provide an apparatus for the heat treatment of metal parts wherein the heating andquenching operations may be carried on cyclicly, whereby substantial economy of operation may be obtained.

A further object of the invention is to provide an apparatus embodying means for agitating the quenching liquid and for simultaneously protecting the same against fire.

A still further object of the invention is to provide a novel method wherein metallic parts are heated to a predetermined temperature and are then introduced into a quenching liquid and wherein during such quenching additional metal parts are being heated and rendered ready for the quenching operation.

I shall not attempt at this time to enumerate the various objects and advantages of the invention, but will proceed with a detailed description thereof wherein other objects and advan-' tages will be specifically mentioned, or else will be apparent from such description.

In order that the invention may be understood readily and its practical advantages appreciated fully, reference should be had to the accompanying drawings, wherein I have illustrated an embodiment of the same in a form which has been found in practice to be very satisfactory; but it will be understood that the inventionv may be embodied in other forms of construction than that shown, and also that apparatus-of different construction from that shown may be employed in the carrying out or practicing of my novel method.

In the drawings:

Fig. 1 is a view in central vertical section, illustrating the essential parts of the construction embodied in the invention;

Fig. 2 is a view partly in side elevation and partly in section taken on the line 2--2 of Fig. 1;

Fig. 3 is a top plan view of the top part of the container for the quenching liquid and showing work supporting means mounted thereon; )0

Fig. 4 is a vertical central sectional view of the topportion of the container for the quenching liquid; and

Fig. 5 is a view in transverse section taken on the line 5-5 of Fig. 4, the work shown in the latter figure being omitted.

In the drawings I have shown a furnace at 1, the interior lining of which consists of bricks or other suitable lining of highly refractory material.

In the construction as shown, the furnace is heated by means of electric heating elements indicated at 2. I have not shown in detail the resistance devices which constitute the heating elements, because any suitable device or devices for the purposemay be employed. Neither shall I describe in detail the construction of the furnace, because furnaces of different construction in detail may be employed.

The furnace in the construction shown is of relatively great length as compared with its diameter, whereby itis adapted for the treatment of relatively long metal parts, such as are indicated at 3 in drawings. Although parts of this character are shown, it is to be understood that the apparatus may be employed for the heat treatment of parts having shapes altogether different from those shown in Fig. 1; for example, parts such as that indicated at 5 in Fig. 4 of the drawings may be subjected to heat treatment 90, in and by the apparatus of my invention.

It will be noted in the construction i 'dicated that the parts 3 are of tubular form and that they are supported upon a spider-like frame structure 10 by means of bent wire devices 11 of hair pin shape, the opposite spaced ends of which project respectively into the ends of the tubes and engage holes in the sides thereof, as shown. The devices 11 are looped around cross bars 12 of the spider 10, as is shown in Figs. 1 and 4 of the drawings. The parts supported upon the spider may be so suspended therefrom or otherwise'supported thereby as to balance each other with respect to the upwardly projecting plate portion 15, which extends cross-wise of the bars 12. The portion 15 is provided with openings 16 near the opposite ends thereof. These openings are adapted to be engaged by means of pins 1'7, which are movably supported upon the lower end portions of the rods 18. The upper ends of posite ends with ,thereon, I have provided sprocket these rods are connected to a cross-head 19, supported by means of a cable 20, which operates over pulleys 21 in the'raising and lowering of the said cross-head to raise and lower the said rods. The cross-head 19 is provided at its opgrooved wheels 21, which engage guide rods 21 The cross-head is thereby guided in its vertical movements. The lower ends of the rods are provided with enlarged terminal portions 22. These terminal end portions 22 are provided respectively with slots 23 extending lengthwise thereof, as shown in Fig. 5, and each of them is also provided with a hole 24 extending therethrough and across the slot 23. Each of the terminal portions 22 is provided with an arm 25 having a downwardly extended, angularly related portion 26. The latter is provided with a hole 27 therethrough in adjoining relation to its end. The pins 17 are slidably supported in the said holes 24 and 27. The pins 17 are provided respectively with openings 30, each of which is engaged by the inner lower ends of levers 31 pivoted upon the terminal portions 22 mounted upon the adjoining spaced lower ends of the rods 18. The upper ends of these levers are connected together by means of the crosswise extending bar 32 which constitutes a weight tending to hold the levers 31 in positions to disengage the pins 17 from the openings 24. Any other suitable means which is capable of effecting quick or rapid disengagement of the spider from the rods 18 may be employed.

The rods 18, the terminal parts 22, the

parts

25, 21, 32 and 10 should consist of metal characterized by its ability to withstand high temperatures. It will be apparent that such capacity is necessary when it is realized that all of these parts are subjected to the high temperatures of the interior of the furnace. It may be noted that the metal of these parts may consist of an alloy of nickel and chromium in suitable proportions. The rods extend upwardly through bushings 35, preferably of metal having high heat resisting characteristics, provided in the upper end or top of the furnace 1, and also through openings provided in blocks 36 mounted upon the upper side of the top of the furnace. The upper portions of the openings through these blocks are enlarged as indicated and provided with packing glands, as indicated at 37, which are held in place by means of covers 38 which are secured to the tops of the said blocks. The presence of these glands prevents leakage of gas and thereby avoids upward drafts of air or other gases through the furnace.

The lower open end of the furnace is adapted to be closed by means of a plug 40 of suitable refractory material, which is supported upon a truck 41, the wheels 42 of whichare mounted upon rails 43, which constitute parts of a frame structure 44. The said structure is provided with rollers upon its opposite sides, as indicated at 45, which engage and are guided, by guide slots 46, which are provided upon the irmer sides of upright columns 47. In order to raise and lower the frame 44 with the truck 41 and the plug 40 wheels 50, which are mounted upon stationary stub shafts 51. Sprocket chains extend partly around and are supported upon these sprocket wheels; One end 01' each chain is connected with the frame 44 and the opposite end thereof is provided with a weight, as indicated at 52. The weights" 52 constitute counter-balancing means for the frame 44, the truck and the plug carried thereby, rendering it easy to cause upward and downward movements of the frame to convey the plug 40 into and from the lower open end of the furnace 1. When in its lowered position, with its upper side below the plane of the lower end of the furnace, the truck may be moved laterally so as to carry it out of alinement with the said open end of the furnace.

When the plug is in open position the work may be conveyed upwardly through the lower end of the furnace into the interior thereof, or may be removed therefrom, as is obvious.

The container 60 for the quenching fluid, which may be oil or other suitable liquid, is adapted to be moved into and out of position underneath and in alinement with the furnace. The container is provided intermediate its opposite ends with channel bars 63, which are secured to opposite sides thereof. The said channel bars, or other equivalent shapes, are provided in adjoining relation to their opposite ends with projections 64, having openings therethrough, which constitute bearings for the shaft 65, upon the opposite ends of which flanged wheels 66 are mounted. The said wheels are supported upon rails 67, which in turn are which are supported upon upright parts 69 of the frame structure of the apparatus. By thus mounting and supporting the container 60, it will be seen that it may be adjusted or moved back and forth upon the rails or tracks 67. For the purpose of effecting such adjustment, I have provided a sprocket chain 70, one side of which has connection, as indicated at 71 with the container. The said chain is supported upon sprocket wheels 72, mounted upon stationary pivots, as shown in Fig. 1. One of the said sprocket wheels 72 is connected with a sprocket wheel 73, which is adapted to be driven by a sprocket chain 74, which engages a sprocket wheel 75. The latter may be driven by means of a crank 76, or by power otherwise applied. The opposite sides of the sprocket chain 74 are guided at intermediate points by means of a guide sprocket Wheel 77. By rotation of the crank 76, it will be apparent that the sprocket chain 74 may be driven in either of two directions and that when so driven the container 60 will be moved in a corresponding direction.

The container is provided upon one side and in adjoining relation to its upper end with'a bracket support 80, upon which a work support spider 10 is adapted to be supported. First, however, the spider in practice ought or at least will be supported by means of a hook 81 at the end of a chain 82, supported upon a block and pulley arrangement 83. The hook 81 is adapted to engage an eye 84, provided in the top edge of the central plate portion 15 of the spider 10. Thespid'er being supported by the hook 81, the work is mounted thereon and, by manipulating the chain 82, by means of the chain 85, the spider, with the work mounted thereon, may'be deposited upon the bracket support 80. The hook 81 may then be released or disconnected from the eye 84 in the plate 15 of the spider 10. When this has been done, the container 60 preferably should be located in position laterally of the furnace 1,"or towards the right of the position in which it is shown in Fig. 1 of the drawings. The spider, with the work mounted thereon, having been deposited upon the work' support 80, the container 60, with the work supported on the bracket 80, is trans lated toward the left, having reference to Fig. 1 of the drawings, soas to convey the spider on the supported upon beams 68,

support spider.

support into position below and in alinement with the furnace 1. When in such position and assuming that the plug 40 has been moved laterally of the furnace so as to leave the lower end of the furnace open, the rods 18, which are long enough for the purpose, are then lowered so as to place the terminal end portions 22 in proper relation to the plate portion 15 of the spider 10 to cause said plate portion to enter the slots 23 in the said portions, as is indicated in Fig. 5. When such relationship has been established, the levers 31 are actuated by lifting the bar 32 to cause movement of the pins 1'7 through the openings 24 to engage the-elongated openings 16 in the part 15. When such engagement has been effected and a pull, by means hereinafter to be explained, is exerted upon the rods 18 to lift the same and carry or convey the work from the support 80 upwardly into the furnace, the weight of the spider and the work carried thereby is sufficient to establish the friction necessary to prevent movement of the pins 1'7 from their engagement with the openings 16 in the plate 15 of the work The work having been transferred or conveyed into the furnace, the truck 41 with the plug 40 thereon is moved into position underneath the open end of the furnace and when in such position the frame 44 is elevated to cause the said plug to enter and close the lower end of the furnace.

1n the operation of the furnace there will be a tendency for the heat to collect in the upper part thereof. In order to equalize the heat throughout the length of the furnace so that the temperature at all points therein will be substantially the same,- I have provided means for causing a circulation of the heated air and gases within the furnace. The means employed by me for that purpose comprises a passageway within the furnace wall, extending from near the top thereof to the bottom. The upper end of the passageway is enlarged, as indicated at 91. and a fan 92 enlarged portion thereof. The said fan is mounted upon a shaft 93 of an electric motor 94, or other suitable power means. By actuating the fan the heated air and gases may be drawn from the upper end of the furnace chamber into the upper end of the passageway 90 and driven therethrough and caused to" be discharged at the lower end thereof into the lower. end of said chamber. Obviously the heated air and gases may be caused to flow in reverse direction with substantially the same effect. By thus circulating the heated air and gases in the chamber of the furnace to establish and maintain a uniform temperature therein, I am enabled to subject the metal being heat treated throughout its entire extent to substantially the same temperature. During the furnace and is being subjected to heat treatment, the container 60 may be located in a position'to the right hand of that in which it is shown in Fig. 1 of the drawings, so as to locate the work support bracket 80 in position to have an additional or new supply of work deposited thereon. The additional or new work having been deposited upon the quenching fluid container is then transferred into position underneath and in alinement with the furnace 1.

Assuming that the work within the furnace has been subjected to the required .heat treatment, the frame 44 with the furnace closing plug 40 supported thereby is lowered and the latter ,by which the new the period that work is located within support bracket 80, the

moved from underneath the furnace. The work is then lowered into the quenching fluid of the container 60.

After the heat treated work has been lowered into the quenching fluid in the container, the latter is then conveyed a further distance towards the left so as to transfer the supporting bracket 80, with the work thereon, into position underneath and in alinement with the furnace. Again the rods 18 are connected with the spider,

ported, and such new lot of work is conveyed into the furnace, after which the lower end of the latter is closed, as previously described.

The new lot of work having been removed from the bracket 80, as stated, the'container then is moved toward the right to a position underneath the lower end of the chain 82, whereupon the hook 81 is again connected with the eye 84 of the spider 10 and the treated work removed. After it is removed additional work may be mounted upon or connected with the spider and deposited upon the work support bracket 80 in the manner previously described or in any other manner. This having been done, the container 60 is returned to a position underneath the furnace 1, and the second or successive lot or batch of work inserted into the quenching fluid, as before described. These cycles of operation may be continued indefinitely or as long as there is a supply of metal parts to be treated.

For the purpose of raising and lowering the rods 18, together with the work supported thereby, I have provided means for winding and unwinding the cable 20 about'a drum 100. For causing rotation of the drum to wind the cable 20 thereon, I have provided a crank 101, by means of which'a gear 102 may be rotated. The latter is in engagement with a relatively large spur gear 103, with which is connected a pinion 104, which is in "engagement with a gear 105, which is mounted upon the same shaft as that upon which the drum 100 is mounted, or is otherwise connected with the said drum. Upon rotation of the crank 101 in the direction indicated by the arrow associated therewith, the drum 100 will be driven to wind the cable 20 thereon to effect an upward or elevating movement of the rods 18, the said drum and intermediate gears rotating in the directions indicated by the arrows associated therewith.

For the purpose of regulating the unwinding rotative movement of the drum 100, Ihave provided a fluid or hydraulic braking means, comprising a pump 108, the rotor or other pumping means of which (not shown) is adapted to be actuated by means of a pinion 109, which is in engagement-with a pinion having rigid connection with a pinion 111, which is in engagement with the gear 103. Rotation of the latter causes rotation of the pinion 111, which in turn causes operation of the pump 108. The latter is connected with a system of piping, through which the fluid, as for example oil, maybe.

driven. When the crank 101 is rotated in the direction to wind the 100, the fluid will be driven from the pump through a pipe 112, which has connection with a pipe 113 at a point a distance from a container 114, which is adapted to hold an extra quantity or surplus of fluid. The fluid which is driven through the pipe 112 passes therefrom into thepipe 113 and flows through the end portion 113 of the latter through the check valve 114, and

lot or batch of work is sup-- cable 20 upon the drum' thence through a portion of a pipe 115 to the opposite side of the pump 108.

The check valve 114'is so constructed as to permit a continued flow of fluid in the manner 5 described during the period that the cable 20 'tative movement of the is being wound upon the drum 100; but tending to prevent flow in the opposite direction and therefore to oppose movement of the drum in an unwinding direction. The cable having been wound up so as to elevate the work into the furnace, the drum may be locked or held in position to sustain the work in the furnace by any suitable means which may be selected, as, for example, a pawl 115. When the drum 100 rotates in a direction, the reverse of that already described, to permit or efl'ect the unwinding of the cable 20, the several gears and the pump 108, previously described, will be driven in directions the reverse of those in which they moved during the rotation of the drum 100 in a direction to wind the cable thereon. To permit unwinding of the drum and corresponding rotation of the various gears the pawl 115 must be released or unlocked. .As the result of such reverse rotation or operation of the drum 100, the fluid will be driven in a reverse direction. In other words, it will be driven from the pump through the pipe 115. The presence of the check valve 114 will cause the fluid to continue through the pipe 115, through the valve 120 (which normally is open) and also through the valve 121 and thence to the container 114, and from the latter through the upper portion of the pipe 113 and through the pipe 112 to the op site side of the pump 108. If, after the work has reached its position in the furnace, the valve at 120 be closed and the crank 101 released the drum 100 would tend to unwind. Such tendency to unwind would tend to operate the pump 108 in a direction to drive the fluid from the pump through the pipe 115- and, the valve at 120 being closed, it will be apparent that the pump will be held against operation except for such leakage of the fluid as may take place. To prevent any unwinding rodrum at such time the pawl 115' should be returned to operative or locking position;

when it is desired to lower the work in or to remove it from the furnace the valve 120 may be ..opened, whereupon the weight of the work, to-

gether with the rods 18 and other appurtenant parts, causes through the action of the cable 20 rapid unwinding rotation of the drum 100. By

adjustment of the valve120 the speed of the unwinding rotation of the drum and of the descending movement'of the work may be regulated or controlled. In order to. stop the work when it has reached a position in its descent which is desired, I have provided a rock shaft 125, having am 126 projecting laterally therefrom into the path of the cross-head 19; When the latter descends it contacts with the arm 126 to rock the shaft 125. The said shaft is also provided with an arm 127 tothe outerend of which the .upper end of a rod 128 is connected. The lower end of the said rod is connected to a cam lever 129 which is in engagement with a pin projecting from the outer end portion of a lever 130 which in turn has connection with and operates to actuate the movable valve member of the valve 121 to close thesame. a

Normallyfthe valve at 121 is open, but when the arm or lever 126 is depressed by the contact therewith of the crosshead 19 to eflect elevation .of the cam lever 129, the lever 13Q is lifted'to into the compartment effect the closing of the valve 121. The closing of this valve interrupts the flow of fluid through the pipe system and thereby stops the downward movement of the work. Obviously, by properly designing valve 121 and its actuating levers and cam, a gradual braking action may be had to gently bring the descending work to a stop at the desired point.

If it shouldbe desired to adjust the work to a lower position after its downward movement has been stopped by closing the valve at 121, such adjustment may be effected by opening the normally closed valve 132 provided in the cross or by-pass pipe 133. The valve 132 is normally retained in a closed position by a spring 134 acting lever 135. Upon the opening of the fluid is permitted to flow from the pipe 115 through the pipe 133 upwardly through a portion of the pipe 113 and thence through the pipe 112. By manipulating the valve 132, the work may be permitted to descend such further distance, after it has been stopped by the closing of the valve 121, as may be desired or until the spider sustaining the work is deposited upon the brackets 135 provided upon the inner side of the upper end portion of the container 60.

In order to prevent the work, in its descending movement, from contacting with or catching "upon the brackets 135, I have provided protecting plates 136, which are pivotally supported at their upper edges as indicated at 137. Their lower edges are held inwardly so that they occupy positions slightly inside of or beyond the inner edges of the brackets 135, as shown in Fig. 1.

Springs 138 interposed between the protecting plates 136 and the adjoining portions of the walls of the container 160 operate to hold the. said plates 136 inwardly, as shown in Fig. 1 of the drawings. The weight of the spider and of the work is suflicient to deflect the plates 136 outwardly'to permit the opposite ends of the spider to engage and rest upon the brackets 135. It will be noted that the container is located above a sump tank 140, the top provided with an elongated opening or slot 142, through which certain pipes, which have connection with the container, project. The sump tank 140 is divided into two

compartments

143 and 144 by means of apartition plate 145. One end of the said plate is connected to an end wall of the tank 140, as indicated at 146, the opposite end of which is spaced from the opposite end wall, as indicated at 147.

The quenching fluid is adapted to be withdrawn with an overflow pipe 151, the upper end of which is connected to and is in communication with the said container near the upper end thereof. The overflow liquid from the container discharges 143. If desired, the quenching fluid may be discharged quickly from the container 60 into the compartment 143 through a relatively large pipe 152, which is controlled by a valve at 153. This valve'may be opened by any suitable means.

A It will be seen that by the provision of the partition plate 145 and by the delivery of the quenching fluid into a compartment on one side 141 of which is By the operation of the said plate and by the withdrawal of the quenching fluid from the compartment upon the opposite side of the said partition plate, a circulation of the fluid within the tank is eflected.

For the purpose of agitating the quenching liquid or fluid within the container 60, and at the same time protecting the liquid against'fire. assuming that the liquid is of an inflammable character, I have provided a means for discharging into the liquid at or near the bottom of the container 60 a suitable gasas for example carbon dioxide. The carbon dioxide may be contained in a pressure tank 155 and conveyed therefrom through

pipe connections

156 and 157. The lower end of the pipe 157 terminates in a nozzle 158, which may be circular in form. Upon the release of the carbon dioxide under pressure from the nozzle 158, it travels upwardly through the liquid and, in so doing, agitates the latter and tends to maintain the same at a uniform temperature. The carbon dioxide, being of a higher specific gravity than air, settles upon the top of the quenching liquid and, being a non-supporter of combustion, operates to protect the latter against ignition.

For the purpose of cooling the quenching liquid within the tank 140, I have provided pipes 160 in the bottom thereof, through which a cooling fluid medium is, or may be, conducted.

It will be seen that by my invention I have provided an apparatus of unitary structure wherein the parts embodied therein co-act and co-operate to effect a result highly practical and desirable in character.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An apparatus of the character described comprising a furnace having a chamber within which metal parts are adapted to be heated, the lower end of said furnace being open, means for opening and closing the open end of said furnace, a container for holding a quenching fluid, a cooling and circulating tank, means free of mechanical connection with said tank for passing the quenching fluid to and from saidtank to cool and circulate the fluid, means whereby the said container may be adjusted into and out of position in alignment with said furnace, means for transferring the heated metal parts from the chamber of said furnace into the said container, and means for agitating the quenching fluid.

2. An apparatus of the character described comprising a furnace having a heating chamber, the lower end of said furnace being open, means for closing and opening the said open end, a container for holding a quenching fluid, means for adjusting said container into and out of position underneath the open lower end of said furnace, means for conveying work into said furnace through the open end thereof and supporting the same therein out of contact with any part thereof, means for releasingthe said supporting means to permit descending movement of the work into the quenching fluid in the said c0n-. tainer, and means adapted to be actuated by a descending part of the said supporting means for interrupting the descending movement thereof at a predetermined point and to thereby interrupt the descending movement of the work in desired relation to the quenching fluid in the said container.

3. An apparatus of the character described comprising a furnace having an open lower end, means for closing and opening the said open end, work supporting means adapted to be moved back and forth in said furnace to convey work thereinto and therefrom, means for elevating the said work supporting means in the said furnace, hydraulic means for holding the said work supporting means in elevated position, means for releasing the said hydraulic holding means to permit descending movement of the said work supporting means to convey the work from the said furnace, and means operable by said supporting means during descent thereof for rendering the said hydraulic means effective to interrupt the descending movement of the said work supporting means.

4. An apparatus of the character described.

with the said supporting means, a drum upon.

which said cable is adapted to be wound and unwound, rotatable means for effecting rotation of the said drum, a closed fluid containing pipe line, a pump included in the said pipe line, and operable by said rotatable means whereby rotation of the said rotatable means to wind the said cable upon the said drum actuates the said pump to cause a flow of fluid in one direction through said pipe line, means whereby when the said drum rotates in a direction to unwind the said cable to actuate the said pump in an opposite direction the flow of fluid through the said pipe line is prevented thereby preventing unwinding operation of the said drum, means for rendering said last means inefiective to permit unwinding rotation of the said drum, and means actuated by contact therewith of a downwardly moving part of the said supporting means for stopping the flow of fluid to interrupt the downward movement of the said supporting means.

5. An apparatus of the character described comprising a furnace having an open lower end, adevice to which work is adapted to be connected, supporting means, means for detachably connecting the said device to the said supporting means, means for elevating the said supporting means to convey the work supported thereby into the said furnace, means for retaining the said supportingmeans in elevated position in the said furnace to support the work therein while it is being heated, means to permit the lowering of the work from the said furnace, a movable container for holding a quenching fluid, means within said container for engaging the said device and supporting the same with the work therein, and means whereby the said supporting means is automatically disconnected from the said device when the latter is engaged by said last means.

6. An apparatus of the character described comprising a furnace having an open lower end,

a device to which work is adapted to be connected, work sulpporting means which is adapted to be raised and lowered in the said furnace,

means for detachably connecting the portions of said supporting means located within the said furnace to the said device whereby the said device and the work connected thereto may be conveyed into, supported within and conveyed out of the said furnace, a movable container for holding a quenching fluid, said container having projections upon the inner side thereof 'near its upper end, upon which projections the said device is adapted to be deposited for support, and means whereby the said device is automatically d sconnected from the said supporting means when it is deposited upon the said projections.

'I. An apparatus of the character described comprising a furnace having an opening therein through which work is adapted to be conveyed into and from the furnace, a device to which the work is adapted to be connected, supporting means projecting into the furnace at a point opposite the said opening, means for detachably connecting the said device to the said supporting means, means for causing movement of said supporting means from and toward the said opening,- a container for holding a quenching fluid, which container is adapted to be adjusted into position in opposed relation to the opening of said furnace whereby the work may be conveyed directly from the said furnace into the said container, the said container having projections which extend inwardly from points near the upper end thereof, which projections are adapted to engage and support the said device, and means for automatically disconnecting the said device from the said supporting means when the said device is deposited upon the said projections.

8. An apparatus of the character described comprising a furnace having an opening in its lower end, a device to which work is adapted to be connected, work supporting means extending into the said furnace through the upper end thereof, means for detachably connecting the said device to the said work supporting means, means for raising and lowering the said. work supporting means to convey work into and from the said furnace, a container for holding a quenching fluid, said container having projections upon 4 its inner side near the upper end thereof upon which the said device is adapted to be deposited when the work is lowered from the furnace into ,the quenching fluid in the said container, and

yieidingly supported means extending inwardly in adjoining relation to the edges of the said projections and operating to prevent engagement of thework with the said. projections upon the downward movement of the work into the said container. 1 a

9 An apparatus of the character described comprising a furnace having an opening in its lower end through which work is adapted to be .-conveyed into and fromthe furnace, work supporting means by which work is adapted to be conveyed into, supported within and conveyed from the furnace, a container for holding a quenching fluid, means whereby said container is adjustably supported for movement transverse- 1y of the said furnace into and out'of position in opposed relation to "the open lower end thereof,

a sump tank located below the said container, an overflow pipe extending from near the top of the said container into the said sump tank, a

discharge pipe extending from near the lower end .of said container into the said sump tank, and a pump mounted for movement with the said container for transferring quenching fluid from the said sump tank intothe said" container.

10. An apparatus of the character described comprising a furnace having an open lower end, means for supporting work within said furnace while it is being heated and for transferring the work from the said furnace, a container for holding a quenching liquid, means for adjustably supporting said container to permit movement thereof transversely of the said furnace into and out of position in opposed relation to the opening in the said furnace, the work being adapted to enter thesaid container as it is transferred from the said furnace. and'means for discharging a gas under pressure into the bottom of the quenching liquid, the said gas being incombustible and operating to agitate the quenching liquid as it flows upwardly therethrough and settling upon and forming a cover for the top surface of thesaid liquid to prevent ignition thereof upon the insertion of the heated work into the said container.

11. An apparatus of the character described comprising a furnace for subjecting metal parts to heat, a container for holding a quenching liquid, means for transferring the said metal parts into the quenching liquid, -a sump tank for containing a supply of the quenching liquid, a partition wall extending through the said sump tank and dividing the same into compartments, pipes leading from the said container and projecting into one of the said compartments and adapted to discharge quenching liquid from the said container into the said compartment, and a pump having an intake pipe which projects into the other of said compartments and also having a pipe leading to the said container, the withdrawal of liquid from the last mentioned compartment through the said-intake pipe causing circulation of the liquid in the said tank.

12. An apparatus of the character described comprising a furnace having an open lower end, work supporting means, a container for holding a quenching liquid, a work supporting bracket projecting from a side of said container, a device to which the work is adapted to be connected, means for depositing the said device with work connected thereto upon the said bracket, means for adjusting the said container to place the said bracket with the said device thereon underneath and in alinement with the open lower end of the said furnace, means for connecting the work supporting means to the said device, and means for elevating the said work supporting means for conveying the said device and the work connected thereto from the said bracket into the said furnace. l

13. Apparatus of the type described, comprising a vertical furnace having an opening in the bottom thereof through which work to be treated may be passed, a quenching tank for said work adapted to be positioned beneath said opening, means for raising and supporting said work within said furnace and adapted to allow the work gradually arresting the downward motion of said 1 work to bring the same in desired relation to the quenching fluid in said tank.

14.,Apparatus of the type described, comprising a furnace for heat treating metal parts, a

quenching tank containing a quenching medium, -means for adjusting said tank into and out of position for quenching, means for transferring said parts to said tank when it is in quenching position, means for continuously introducing cool quenching medium into the bottom of said tank 1 0 to thereby replace the heated quenching medium of said tank with fresh'quenching medium, means for removing the heated quenching medium from the top of said tank, means for cooling the heated quenching medium to enable repeated use thereof, means for continuously agitating the quenching medium insaid tank, and means for quickly removing the quenching medium from said tank when desired.

15. Apparatus of the'type comprisl50 ing a vertical furnace having an opening in its lower end through which work to be treated may be passed, one or more heat resisting rod-like work supporting members extending through openings in the top of said furnace, and means for sealing said latter openings at all times to prevent leakage of gases and creation of upward drafts of air through said furnace, whereby said furnace is open at its lower end only.

16. Apparatus of the type described, comprising a vertical furnace having an opening in its lower end through which work to be treated may be passed, one or more heat resisting rod-like work supporting members extending through openings inthe top of said furnace, and means comprising packing glands through which said rod-like members pass for sealing said latter openings to prevent leakage of gases and creation of upward drafts of air through said furnace, whereby said furnace is open at its lower end only.

17. Apparatus of the type described, comprising a vertical furnace having an opening in the bottom only thereof through which work to be treated may be passed, heat resisting work carrying spiders to which respective lots of work may be connected outside said furnace, and one or more heat resisting rod-like spider supporting members extending into said furnace through the top thereof andadapted to be raised and lowered therethrough to convey said work lots into and out of said furnace.

18. Apparatus of the type described, comprising a vertical furnace having an opening in the bottom only thereof through which work to be treated may be passed, heat resisting work carrying spiders to which respective lots of work are adapted to be connected outside said furnace, and a plurality of heat resisting rod-like spider supporting members extending into said furnace through the top thereof and adapted to be raised and lowered therethrough to'convey said work lots into and out of said furnace, said rod-like members having quick detachable spider engaging devices at their lower ends.

19. An apparatus of the character described comprising a furnace having an opening therein through which work is adapted to be conveyed into the interior thereof, a device to which the said work is adapted to be connected, supporting means for said device, means for raising said supporting means and adapted to normally permit rapid descent thereof, means for holding said raising means in position to sustain the work within the said furnace, means for releasing said holding means, and means operable by said supporting means in its downward movement to reestablish the said holding means to interrupt the downward movement of said work.

20. In apparatus of the type described, a vertical furnace having an opening in the bottom only thereof through which work to be treated may be passed, a door for said opening, and. means for supporting said door mechanically free of said furnace so as to permit bodily vertical movement of said door to open and close said opening and sideward movement thereof to clear said'opening for work.

21. An apparatus of the character described comprising a furnace having an opening in its lower end, a device to which work is adapted to be connected, work supporting means extending into the said furnace through the upper end thereof, means for detachably connecting the said device to the said work supporting means, means for raising and lowering the said work supporting means to convey work into and from the said furnace, a container for holding a quenching fluid, said container having projections upon its inner side near the upper end thereof upon which the said device is adapted to be deposited when the work is lowered from the furnace into the quenching fluid the said container, and yieldingly supported means extending inwardly in adjoining relation to the edges of the said projections and operating to prevent engagement of the work with the said projections upon the downward movement of the work into the said container, said last means comprising plates submerged in the quenching fluid which serve as dash-pot cushions to reduce the shock of landing of said work on said projections.

22. Apparatus of the type described, comprising a vertical furnace having an opening in the bottom thereof through which work to be treated may be passed, a quenching tank for said work, means for rectilinearly adjusting said container into and out of position underneath said opening, and means for raising and lowering said work into and out of said furnace.

nace for heat treating metal parts, a quenching tank adapted to contain a combustible quenching fluid, means for transferring said parts to said tank, means for supplying quenching fluid to said tank, means for preventing said fluid from rising in said tank above a predetermined level to maintain a space in said tank above said fluid, a storage tank adaptedto contain a heavy non-combustible gas under pressure, and a conduit leading from said storage tank and terminating in a discharge nozzle inside said quenching tank near the bottom thereof, whereby gas from'said storage tank may be discharged into said quenching medium near the bottom of said quenching tank.

HORACE C. KNERR.