US2525727A - Furnace loading and discharge mechanism - Google Patents

Description

L. B. ROSSEAU FURNACE LOADING AND DISCHARGE MECHANISM Oct. 10, 1950 5 Sheet-Sheet 1 Filed J uly 26, 1946 INVENTOR Leon ATTORNEYS.

Oct. 10,1950 L. B. RossEAu 2,525,727

FURNACE LOADING AND DISCHARGE MECHANISM Filed July 26, 1946 5 Sheets-Sheet 2 6J2 65 fi 6:45

Oct. 10, 1950 L. B. ROSSEAU 2,525,727

FURNACE LOADING AND DISCHARGE MECHANISM Filed July 26, 1946 5 Sheets-Sheet 5 INVENTOR Oct. 10,1950

L. B. ROSSEAU FURNACE LOADING AND DISCHARGE MECHANISM 5 Sheets-Sheet 5 Filed July 26, 1946 I if z 5 M m mw w N 2 a INVENTQR [standing advantages or p freedom from scaling and formity of heating, high speed heating without q compactness of means in the bath to they are heated, lifting them thefurnace in a nearly ingthem for conveyerwithdrawal to the rolling the furnace and heated there.

conveyer to from a C sliding, to withdraw the holding Patented Oct. 10, 1950 UNITED STATES PATENT OFFICE FIlRNACE LOADING AND DISCHARGE- MECHANISM LeonBidwell Rosseau, Narberth, Pa., assignor to Ajax Electric Compan y, Inc., Philadelphia, Pa.,

a corporation of Pennsylvania Application July 26, 1946, Serial No. 686,549

M 1. My "invention' relates to mechanization of i chargingand discharging of pit-type furnaces, *fparticularly salt bath furnaces, especially for heating billets andthe ike. fApurpose ofgmyj nve tion is to make the outit furnace heating, especially in salt baths,. available on a practical :fmass production basis for-:the heating of billets lbillets or similar metallic shapes into and out nOi a pit-type furnace such as a salt bath by an individual holder, preferably in cooperation with guide the holder, means in the bath to support the billet or similar shape during heating and approach and discharge conveyerscooperating with the holder.

A further purpose is mechanically to handle billetsand other sizes of metal, taking them from any suitable source,"tilting them to nearly vertical positions,'lowering them one at a time into a salt bath or other pit-typefurnace, where one at a time from vertical position and tiltof forging point. i v

i A further purpose is to feed billets horizontally upon a horizontal track, which is capable of bebe lowered into After heating, the billets are withdrawn in a nearlyvertical position, are' tilted and are fed by a horizontal the heating rolls, or to the point .at which they are to be forged.

A furtherpurpose of my invention is mechani- /cally to carry billets or other objects to be heated ing tilted so that the billets can "from anysuitable source, to tilt and lower them ;in a salt bath furnace, to heat them within the furnace and to lift them, one ata time, from fthe furnace, tiltingthem for conveyer withdrawalto the rollingor forgin'gpoint.

A further purpose is carriage into engagement hoist, while holding the billet against mechanism so a that the billet is controlled by the yoke and to w' the ke intothe furnace.

the installation due to high to tilt a billetsupporting with a transfer yoke zit-claims; (c1. Zia-18) A further purpose is to transfer 'abillet horizontally to a tilting carriage, tilt the carriage into billet engagement with a suspended yoke and lower the yoke and billet into a heating furnace.

A further purpose is to provide a furnace cover with openings matching'the product to be heated therein, to lower the product one at a time parts seen in Figure 3.

through one i of these openings and as a final part of the lowering operation to close the opening.

A further purpose is to support and guide a *billet in a salt bath on the rest bars inclined to the horizontalat an angle of more than 65, and preferably nearly vertical.

In thedrawings which are largely diagrammatic, I have preferred to illustrate a few slightly different forms only, showing, forms which are practical and effective but which have been selected because they are particularly well suited to carry out my invention.

Figure 1 is a top plan view of a structure capable of carrying out my invention but omitting the hoist seen in other figures.

Figure 2 is a sectional elevation of. the structure of Figure 1, but withlthe hoist in place.

Figure 3 is a fragmentary sectional side elevation showing parts of Figure 2 to a larger scale.

It omits the outline of the salt bath and the hoist.

Figure 4 is a fragmentary end elevation of part tilting table and means for Figure dis a perspective showing the upper of the salt bath, a

. tilting the table.

Figure 5 is a largely schematic perspective view to a smaller scale of a modification of the structure of Figure 5. v

Figure 6 is a perspective view of a portion of the side wall of the salt bath furnace and guides thereon for supporting the billet while in the a bath.

Figure 7 is a perspective showing a yoke which i *may be used inhandling the billets.

Figure 8 is a fragmentary perspective of a, salt bath showing refractory rests.

Figure 9 'is adiagrammatic central vertical longitudinal section of a salt .bath showing the work inclined at an angle closely approaching the horizontal. 3

In-the drawlnga'like numeralsJefer to like parts.

In the prior art there are numerous applications in which it is necessary to heat billets, blanks, or similar metallic shapes, for example preliminary to forging or speclalized forging 3 operations such as heading, up-setting or the like, as well as extruding, rolling, and other forming and similar operations. The general prior art practice has been to use radiant fuel heating, which of course presents the difiiculty that the operation is slow and the cycles are correspondingly long, whereas the effect on the work is sometimes harmful, causing scaling, decarburization, carburization, and other similar difficulties.

Numerous advantages exist in pit-type furnaces, but they generally have not been available for heating of billets and similar metallic shapes because it has been impractical on a high production basis to charge and discharge such furnaces. Conventional horizontal conveyers have not been capable of use because the furnaces normally can not be entered except from the top.

Special advantages exist in the use of salt bath furnaces, since they make possible heating under substantially complete protection from oxygen of the air, thus protecting against scaling and decarburization. They necessitate no contact with fuel and therefore protect against carburization, they heat much more rapidly and far more uniformly than fuel fired furnaces, thus reducing the incidence of rejections through cracking, and permitting grain size control, and due to the high production of an individual furnace, it is possible to reduce markedly the size of the installation which would be required where fuel heating was employed.

The problem is complicated because the high production rate and the requirements for uniform and expeditious flow of the material through the furnace preclude the possibility of using the ordinary hand charging and discharging methods. As high temperatures are involved, frequently close to the limit of serviceability of ordinary metallic materials, the materials engineering problem further limits the designer in the selection of mechanism to accomplish the purpose.

While the products heated are likely to be billets and will commonly be referred to herein as billets, since they will be generally of rectangular or cylindrical exterior contour, it will be understood of course that other similar shapes may be employed such as shafts, tubes, rods, blanks, and the like which will undergo heating either for purposes of forming such as forging (including specialized types like heading, coining, upsetting) as well as extruding, rolling or the like. It will also be understood that the mechanism of the invention may be used in connection with heat treating, such as austenitizing, quenching, whether isothermal or otherwise, stress relieving or the like. It will also be understood that my invention may be employed to heat only a part of the work piece for selective or localized heat treating, forming or other operations.

In the preferred embodiment, I propose to use a salt bath furnace to support a number of billets side by side in nearly vertical position while 7 they are being heated.

My invention concerns primarily the manner of charging these billets in the intended positions into a salt bath or other pit-type furnace and discharging them from these positions, and of handling the billets from a horizontal position as delivered from a source, to a position within .the bath preferably nearly vertical and, after heating, from the position in the bath to a horizontal conveyer upon which they may be delivered to the rolling mill or to the forging hammer or press, or other point of subsequent use.

source where they are piled horizontally or where readily they can be fed in a horizontal position on approach feed rolls. I am assuming that the billets H] are of nearly square rectangular cross section and are rested edgewise (that is with the edge i l formed by two meeting faces I2, l3 down) but still horizontal in grooved rollers of a conveyer I l where the billets will ordinarily be progressed by hand movement of the billets. There is no need for power driving of the rolls.

For convenience of identification the faces directly opposite l2 and I3 will be indicated as I2 and [3, the leading billet end will be indicated as and the trailing end as [6.

The approach conveyor [4 is illustrated as comprising side rails l1, l8, suitably supported,

in which are carried the spindles I9 of grooved rollers 20 whose grooved faces 2| and 22 receive the billet faces [2 and I3.

The rollers 20 deliver the billets, one at a time, to correspondingly grooved rollers 23 of a train 24 having bearing in the side rails 25 of a carriage 26. The carriage 26 can be moved transversely of the delivery conveyor length so that the train of rollers 24 may be made to align with the delivery train.

In the form of Figures 1 to 5 the carriage spans a considerable range, riding on wheels 21, rotatably mounted on under-carriage structure 2i, and which wheels rest upon the rails 28 of a platform or apron 29. The platform or apron is swung in vertical planes to an arc of nearly so as to swing the platform or apron up into the dot and dash position of Figures 2 and 3, but to swing the carriage along with the platform or apron. In these two figures a portion of the carriage is shown in nearly vertical position but most of it has been left out in the dot and dash showing as unnecessary.

In Figure 5 the carriage only is swung and the platform, in the form of a guide rail only, is fixed as later described.

When the carriage and platform of Figures 1 to 5 inclusive are swung to the dot and dash position together, it will be evident that the wheels 2'! must be protected from falling off of the rails 28. For this reason a guard rail 30 is used which prevents the wheels 2'! from leaving the track.

It is also clear that the billets l0 shown in Figure 2 will slide off their rollers when the. carriage has been tilted in a nearly vertical plane unless the billets are restrained by some stop. In order to take care of this, a hook 3|, pivoted at 32, is pressed upwardly by spring 33 so as to engage the billet end. The billet can be released from the hook by pulling the hook away from the billet by any implement inserted within an opening 34.

Because it is the intention to tilt the billet nearly 90 to some such position as 35, but not too far for a vertical component of the billet weight to rest upon the train of rollers 24 upon the carriage, the billet will be held by the hook until the hook has been released as indicated.

The tilting frame or apron as shown is made up of channels 3? (Figure 5) welded to transverse tieing channels 37 supported when down by a shape shown as an I-beam 38 on brackets 35 connected with or adjacent to the side of the salt bath furnace. The frame is swingably supported and tilted by arms w connected to a shaft ll rotatably supported on'thefurnace by brackets 12. The frame or table merely rests 'ul onTthe Mam which gives it. support at all points along thelength of the beam.

.The salt bath furnace43, as shown, is. provided with guides against which the billets can rest, and for that reason considered. as restsjf .At. intervals along the length of one inside wall 43' of the furnace .parallelthereto there are four such rests shown, .eachoneduplicating thatshown in Figure 6, and comprising .parallel guides, rods or bars 44, supported by brackets .45 and. The parallel bars. are sloped downwardly; and i111- wardly; toward the interior. of the furnace .so as to make sure thatthe billetsrest uponthe bars and against a stop 41 and do not fall away from the rest bars. The angle of the bars shouldprefl.

erably be almost but not quite verticalas shown; most desirably making an angle of from 65 to 85 with the, horizontal, but permissibly being inclined at a less steep angle as later shown. In Figural, four of such pairs. of rest bars are shown, spaced along the side wall 43 of the furnace. N

The salt bath may be heated in any preferable manner, but in the preferred embodiment it is intended to be of the electrode-heated type. Accordingly suitable pairs of electrodes 46 are illustrated. It is preferred to provide an ample quantity of salt at B adjacenteach billet. The electrodes are suitably electrically connected to an electric heatingdevice 5 I, which may be a transformer or other suitable mechanism for operating salt bath electrodes. n

In addition to the sides43 and 49, the furnace .is provided with ends 5 2,,bottom 53 and top or cover 53' and a charge of fused salt 54.

In Figure 7, I show. a holder, yoke or cradle 55 of high temperature alloy, suitably comprising side pieces 56 connected atthe top bya tie 51 inwhich eye 58 is carried, and a cross piece 59 near the bottom which is adapted to support the bottom of the billet at such time as the carriage is elevated and the hook 3 i has been released. At the bottom of the side bars of the holder, cradle or yoke are provided feet 60 which engage the front surfaces of the pair of rest bars 44 with which the yoke is associated. There is a separate yoke for each pair of guides and the yokes stay in the salt bath during the heating operation. In the elevated position of the yoke, the feet iii] engage stops 60' extending beyond the rest bars on the outsides, out of line with the billets and are prevented from leaving the rest bars at the upper ends. i l

Asshown in the drawings, the guide bars or rests will normally be spaced more closely than the side bars 55 of the yokes so that while the billets are resting gon and guided by the guide bars, they will be surrounded by the side bars .56 ofthe yoke.

Before the billet is tilted in position, and as a part of the operation of delivering it to the furnace to be heated, the carriage must be aligned with a pair of empty rest bars in the furnace, and the yoke used with this pair of rest bars must be elevated and held in elevated position so as to permit the billet to be inserted between the side .bars of the yoke.

The carriage is shifted along the length or the rails 28 until it reaches a notch where it can registered and held by the catch.

The empty yoke or cradle is lifted to elevatedposition and held tight in the position shown in dot and dash lines in Figure 2 by a hoist which comprises a hydraulic cylinder 65, supported at a piston (not seen) from which piston rod l 66 is operated, a rack 6'! moved by the piston rod- 66, a rack gear 68 engaging the rack and a pulley,

69 fastened to the same shaft as the gear. A- valve I55 controls fluid operation of the cylinder.- The pulley mounts cable ID. I

The cable is removably connected to the eye 58, so that by admitting fluid underpressure tothe cylinder 65 to force the piston to the right in the cylinder, the yoke can be lifted and held under tension in the position seen in Figure 2.4 The feet of the yoke engage the fronts of the rest bars and the bottom of the yoke is thus sup-- ported. The feet are limited, in upward move-- ment, as by the steps 50. i a i The yoke is shown in Figure 2 (dot and dashl as extended all the way out and the cable is under tension. When the carriage is tilted against a yoke in upper position, the billet is delivered between the side bars of the yoke, since the spacing has been selected to fit the billet, and if the yoke be supported upon the upper part of the rest bars of the pair, the upper part of the yoke is suspended and may be held tight by the cable Ill. The parts are held in this position while the hook 3 I, seen in Figure 2, is withdrawn from the end of the billet to allow the end of the billet to rest upon the cross bar 59 of the yoke.

The carriage is maintained in tilted position to support the billet weight under part of the carriage by the rolls 24, while the billet is being lowered (or raised on the reverse movement), the hoist cable is slacked and the billet is allowed to slide down the rolls 24 to a position where the support of thebillet passes to the sloping side, bars of the particular rest pair upon which the billet is to be deposited. In this form, as in Figure 5 2, the billet is maintained in diagonal position, its diagonal sides resting upon the side bars of therest. .As the billet is slid down the roller 24 and the rest bars, the angle 1 l of the billet thus: lies between the rest bars and is pressed against; these rest bars by the horizontal component of; the weight of the sloping billet.

Upon the upper end of the yoke is supported'a. closure ll which fits into anopening l2 in the: cover 53 protecting against loss of heat at this; point. The openings 12 are preferably individuali to each pair of rest bars to permit insertion; and withdrawal of the respective billets and the open ings are covered when the yokes are in lowerposition. 9 1 i i A separate hoist is preferably located above each. of the billet heating positions in the salt bath, although of course, a movable hoist could. be used. The mechanism is provided with suitable supports and the rack is supported against disengagement from the gear by well known.

means.

Considering now the detail of the carriage tilt. ing mechanism, the shaft 4| by which the carriage is tilted, is'mounted to turn in bearings 74.

Along with the arms 40 Supporting the swinging platform, thecarriage weight is..counter-balancedby a weight 15 mounted upon ES and held in position by set screw. 5'1, capable of adj ostment upon this arm to adaptthe counterweight. q to difierent ,weights. .of billets. The adjustingscrew 17' also permits adjustment of weight.

position on the arm 16 or substitution of weights. This adjustment may be desirable for any of a number of reasons, either because a different size billet is being handled or because a billet is of different metal.

At the opposite end of the shaft M from the counterweight is located an arm 18, which is swung by an air cylinder 19, provided with an air control valve '19, through a piston rod 89 fastened to the arm by yoke 8|. The air cylinder is mounted about a pivot rod 82, which is attached to the salt bath casing or to associated structure and is seen in Figure 1.

In operation, before the carriage is aligned with a selected (empty) heating position and is tilted to the position seen in dot and dash in Figures 2 and 3, the yoke for the heating position at which the billet is to be located is connected with its hoist cable It at the eye in the yoke and is pulled out to the position seen in dot and dash in Figure 2.

The cable is held taut and the yoke is maintained in the proper position with respect to the other parts by engagement of its feet with the bars of the rest, so that when the carriage has been tilted the billet is thrown up into the opening between the yoke sides and the bottom of the billet is placed in position to nearly engage with the bar of the yoke. At this time the billet is still held up by the hook 3|. When the parts come to rest in the position shown, the hook is withdrawn by a wire or other implement engaging the opening in the hook and pulling toward the bottom of the illustration Figure 3. This results in the holder releasing the billet from the hook and resting the billet upon the cross bar of the yoke.

The hoist is then slacked and the yoke as well as the billet within the yoke are lowered to a position corresponding with that shown for the billet in Figure 2. The cable of the hoist is then released from the eye of the yoke and the yoke is left within the heating salt, the billet and yoke being heated concurrently and remaining together until such time as the billet is sufficiently hot for the rolling or forging or other operation.

The carriage is again aligned with the billet position, and the carriage is tilted.

Connection is made with the hoist through its cable Hi, and the billet is withdrawn to its position seen in dot and dash lines in Figure 2. The carriage is tilted back to the position seen in full lines in Figures 2 and 3.

During the hoisting operation the billet shoves the hook 3! back against the spring (due to the sloping nose on the hook) and when the billet is fully raised the hook latches under the lower end of the billet which has just been hoisted. The carriage is aligned along the frame with the roller conveyor 73 (suitably identical with the approach 'conveyor) by which the billet is conveyed in the direction of the arrow to the rolling mill, or point at which forging is to take place, or other point of use.

It will be obvious that the several roller conveyors can be operated by power if desired but that normally the distance of travel and the absenc of regularity, and the fact that the billets must be handled when they are heated sufficiently and when the rolling mill pass or forging hammer or press is ready to receive them rather than on a time schedule, makes it ordinarily not worth while to apply power to these horizontal conveyors.

it will be evident that an important advan tage of the invention is that the billets are preferably nearly vertical when they are heated, so that distortion will be a minimum, and the billets are laterally supported over their entire length, further reducing distortion.

In Figure structure is shown capable of performing the functionperformed in Figures 2 and 3, namely of feeding a billet or other article to be heated in a furnace near its charging opening and tilting the billet to a particular position above and in line with a resting place in the furnace for the billet. However, instead of operating a carriage on which the billet is mounted along the length of a platform or frame fixed except for tilting of the structure as in Figure 5, the form of Figure 5 operates on a wholly fixed bed or table and not only tilts the carriage at a proper place for performing the function, but shifts the carriage on the length of the fixed table.

In this figure the furnace 43 is shown in fragmentary form supporting the brackets 83 upon which a rail 84 is fixed. The carriage 85 is indexed by a pivoted latch 86 engaging in one of the notches 81 in the rail so that the carriage may be stopped directly opposite a pair of rests within the furnace, which rests are intended to receive this particular billet.

A square shaft 88 extends across the furnace parallel to the rail, and carries a sliding collar 89 along the shaft. At any point at which it is desired to tilt the carriage, the shaft 88 is turned by mechanism of the same character as shown in Figure 5 by which in that figure the support or table is tilted.

The carriage in Figure 5 is provided with rollers 90 resting upon the rail 84.

The carriage in Figure 5 when shifted performs the same functions that the carriage shown in Figures 1 to 4 performs. Figure 5 illustrates the fact that the carriage and table are capable of presentation in different forms to secure the same result.

In Figure 5 the carriage is tilted directly rather than by tilting a platform upon which a carriage runs. Consequently the weight to be moved is rested upon a carriage which is connected slidably with a non-circular or splined shaft by which the carriage will be tilted. The tilting mechanism may correspond otherwise in all particulars with the tilting mechanism shown in Figure 5.

The non-circular or splined shaft is connected through an arm 9| with the carriage which in the present case merely rests through supporting rollers 90 upon a single fixed rail along which it travels in order to serve the particular rest slide or guide in the furnace at which the billet is to be deposited for heating.

After the selected position has been found, the operation is carried out by the cylinder, piston rod and lever shown in Figure 5, carrying out exactly the previous operation of throwing the billet carriage upinto nearly vertical position, attaching the hoist cable for the particular position in question to the eye in the upper end of the yoke, pulling the hook out of its position and lowering the billet into its proper place in the furnace by use of the cylinder, rack, gear, drum and cable corresponding to those -in Figure 2.

It will be apparent of course that while in the preferred embodiment I have shown metallic bars or rods, suitably of heat resisting alloy, making up the rests 44, it is not essential to employ such material. Figure 8 illustrates one or a group ofrefractory rests 4'4 which may be functionally identical with the, metallic rests shown, and may be constructed as a part of or adjunct of the furnace wall 43. As shown, the refractory rest is inclined slightly to the Vertical and is provided with bar-like guide edges 92 suitably spaced to engage adjoining sides of the billet or the like, and having a longitudinal recess 93 between the edges 92.to receive the longitudinal edge of the billet which adjoins the wall 43'. At the bottom an abutment 41' is provided to engage the lower edge of the yoke and support the billet in heating position. To permit circulation of hot salt behind the billet, the edges 92 are preferably notched at 94 and a series of openings 95 are provided into the space 93. The structure of Figure 8 may operate as in the other forms.

In some cases the invention may be applied to applications in which it is necessary to incline the rests 44 at an angle which slightly varies from the horizontal as shown in Figure 9. This illustrates the heating of the end of a long tube 96 for a forming operation. The tube is inserted long-ways of the salt bath on a rest M supported bysupports 45' and 46 and having a suitable stop H for the yoke 55. The yoke 55 may suitably be identical with the yoke shown in the other forms, except that since the tube 96 is of indefinite length, the upper end of the yoke is provided with a bridge ,9! which extends above the tube and connects two sides of the yoke, carrying an eye 58 for engagement by the hoist.

It will be evident of course that thislor other forms of the invention may equally well be appliedfor heating parts for heat treatment,

rather than forming. For example, the, tube 96 may be heated for hardening in the case of steel, or for precipitation hardening in the case of a non-ferrousalloy of precipitation hardening type.

My invention is capable of operating with furnaces of other types but it has been illustrated upon a salt bath furnace of rectangular cross section with mechanism by whichthe billets to be heated may be immersed side by side in the molten salt and from which they can be withdrawn.

It is necessary that the billets be spaced by a sufficient bulk of molten salt so that each billet is heated independently of any other, whether r there be another billet in the adjacent position or not. l

The billets to be heated inevitably tend to chill the salt of the bath and the heat withdrawn by one or more of the billets must be replaced by heat addedto the bath, From this standpoint my heating system is not independent of the number of objectsfherei-n called billets for convenience-but the volume of bathmandthe actual space between adjacent, billets must 1 suflicient so that the bath is not undulychilled by the insertion of a new billet or the withdrawal of the heated billets. l

In order thatthe billets may reliably maintain their position as set, the pairs of guides or rests are spaced fromthe furnace wall by the brackets so as to give a slope against which the billets will rest reliably. The spacing of the rests both from the walls and from each other is for the purpose of providing abody of molten salt between the bar andthe wall and for supporting the billets in such a way that the billet sides are diagonal to the adjacent side of the furnace, so that the excess of molten salt in the furnace will be equal} ized on the two facesbetween the billets and the wall and the two faces away from the wall. The diagonal placing of the billet is a further and decided mechanical advantage in that the spaced rests perform a better guiding and supporting function against a rectangular cross section turned 45 than they would against the same section lying fiat on the guides. For example, if the billets were packed with one flat side toward the closely adjacent wall, the necessary supporting bars or plates would undoubtedly shut off access of the salt=to that place and there would be salt from that side available to one face only, whereas the salt of the bath would have access to the remaining three sides, except insofar as structure preventing side movement might interfere with side access of salt to the two adjacent sides.

At a suitable point near the bottom of the guide bars individual stops are intended to limit the downward feeding movement of the individual billet and to support the billets so that the cable hold by which they have been lowered may be released and the billets may be relied upon to lie against the sloping guide bars without other support. This makes it possible to use a single hoisting and lowering mechanism for all of the billets fedin whatever position they are to rest,

with release of the lifting and lowering mechanism during the time when the billet is soaking in the bath.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying thestructure'shown, and I, therefore, claim all such insofar as spirit and soopeof my claims.

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

1. An approach conveyor, a carriageadapted to be adjusted to align with the approach conveyor, a salt bath furnace having restsior the object to be heated at intervals along the length of the furnace, to which rests the carriage may be brought in alignment, tilting mechanism by which the carriage may be tilted and returned to the horizontal, hoist mechanism by which the object to be heated may be lowered andsubsequently' may be lifted, being intermediately heated, and a discharge conveyor with which the carriage may be aligned to deliver the objects to a point of use after the objects have been heated.

2. A work carriage movablealong the edge outside ofa furnace, 'a conveyor upon the carriage adapted to receive a billet to be heated,

tilting means for thecarriage whereby the billet is heldin nearly vertical position, a yoke for, en,-

gaging thebillet when'the carriage is tilted, hoist means for lifting and lowering the yoke in alignfnent with the conveyor upon the carriage and w a rest for the billet in alignment with the con veyor on the carriage.

3, In a charging and discharging mechanism for furnaces heating billets and the likega support for a billet in a horizontal position, tilting means for the supporttilting the billet, 'a stop preventing the billet from sliding from the support, a yoke for receiving the billet, a hoist hold ing the yoke in a-position to which the billet is tilted, and a rest within the furnace in line with the yoke, whereby when the stop is released the.

they fallxwithin' the reasonable 1 1 billet may be lowered by the hoist to its position of rest within the furnace.

4. In a charging and discharging mechanism for billets and the like, a furnace, a rest and guide within the furnace sloping with respect to the vertical, the furnace being open above the guide to admit the billet, a yoke connected with the guide, means on the yoke to prevent withdrawal of the yoke wholly from the guide, a hoist adapted for connection with the yoke to hold the yoke in raised position and to lower the yoke and billet into the furnace, a tilting support for a billet adjacent to the furnace, a stop upon the support to prevent sliding of the billet, registry means connected with the support to determine a point of alignment with the rest and yoke, tilting means for tilting the outside support to bring the billet up into the yoke and means for releasing the stop to permit lowering on the tilting support while the billet is carried b the yoke.

5. In a charging and discharging mechanism for furnaces, a carriage, tilting means for turning the carriage from approximately horizontal to nearly vertical position, a conveyer on said carriage upon which billets are carried, a furnace at whose edge the carriage is located, guiding and supporting means in the furnace adapted to receive the billet, a stop preventing the billet from sliding prematurely from the carriage as the carriage is tilted, elevating means for lifting the billet in its tilted position or for allowing it to lower and a support connecting the elevating means with the billet.

6. In a charging and discharging mechanism for furnaces, a rest within the furnace upon which a billet is adapted to be placed, a yoke surrounding the billet and adapted to remain in the furnaceduring the heating of the billet, a hoist for raising and lowering the yoke, a carriage having conveyer rollers adapted to be tilted into position in line with the hoist and yoke, means for tilting the carriage to inclined position, a stop preventing the billet from movement from the carriage in one direction, a track for the carriage,

an approach conveyer with which the carriage 1 is adapted to register at one end of the movement of the carriage on the track and a discharge conveyer with which the carriage is adapted to register at an opposite end of the carriage movement.

'7. In a furnace, a downward sloping pair of guides in the furnace, a stop limiting the lower movement on the guides, a transfer yoke moving on the guides, a carriage adapted for movement along the side of the furnace, means for tilting the carriage to move the billet into the transfer yoke, hoisting means for maintaining the position of the transfer yoke and a movable stop for holding the billet in the carriage until it reaches its position in the transfer yoke.

.8.,In a charging and discharging furnace, a plurality of downwardly sloping guides and rests side by side along at least one furnace wall, a tilting carriage movable along the length of the wall, indexing means for insuring registry of the tilting carriage with a particular guide and rest, a movable stop engaging the end of the billet to prevent accidental sliding of the billet along the tilted carriage, a transfer yoke adapted to follow a pair of guides, a hoist for lifting and lowering the yoke and holding it in raised position registering with the position of the billet when the carriage is tilted and means for moving the stop out of the way whereby the weight of the billet is assumed by the transfer yoke.

9. In a charging and discharging mechanism for furnaces, a furnace having supporting means therein and a stop to limit the extent to which a billet is fed into the furnace, a yoke adapted to cooperate with the supporting means to lift and lower a billet, feet. upon the yoke adapted to rest upon the supporting means when a yoke and billet are lifted to an upper yoke position, a hoist connected with the yoke to lift and lower the yoke and a swinging carriage adapted to carry a billet and in one swinging position adapted to insert a billet within the yoke.

10. In a charging and discharging mechanism, a furnace having billet supporting guides sloping downwardly and inwardly along at least one furnace wall and open at the top to permit billet insertion, transfer yokes adapted to engage the guides, means for preventing the transfer yokes from being removed wholly from the furnace, hoists adapted to move the yokes up and down, each hoist being individual to each set of supporting guides and rests, a carriage adapted to move into alignment with any one of the sets of guides, tilting mechanism for the carriage, means for alignment of the carriage with any of the sets of guides and a removable stop preventing sliding movement of the billet upon the carriage.

11. In charging and discharging mechanism for furnaces, a furnace having supporting means therein and a stop to limit the extent to which a billet is fed into the furnace, a yoke adapted to cooperate with the supporting means to lift and lower a billet, a hoist engaging the yoke and lifting or lowering as required, a furnace cover having an opening for insertion and removal of billets and a closure for the cover opening carried by the yoke and removed when billets are hoisted and reset when a billet is lowered into the furnace.

- 12. A salt bath furnace, a cover therefor having an opening, a yoke adapted to carry work down into the furnace and remove the work therefrom through the opening and a closure for the opening carried by the yoke, whereby the closure is removed during upward movement of the yoke giving space for the work being heated to come out through the opening and the closure is replaced to close the opening.

13. In a furnace for heating billets, a furnace casing, a furnace cover having an opening, a support for a billet beneath the opening, and sloping with respect to the vertical, a yoke maintained in contact with the support and adapted to carry work into the furnace to a position resting on the support and to withdraw it therefrom and a closure for the opening carried by the upper part of the yoke.

14. In a furnace for heating billets, a furnace casing, a cover therefor having an opening, a support for a billet beneath the opening, and sloping with respect to the vertical, a yoke maintained in contact with the support and adapted to hold a billet during raising or lowering, a closure for the opening carried by the upper part of the yoke, a carriage, rollers on the carriage supporting a billet, means for shifting the carriage so that the carriage corresponds in position with the support, means for tilting the carriage to bring the billet within the yoke and means for lifting or lowering the billet and the yoke.

15. In a furnace for heating billets, a furnace casing, a furnace cover having an opening, a support for a billet beneath the opening, and sloping with respect to the vertical, a yoke maintained in contact with the support, a closure for the opening carried by the upper part of the yoke, a tilting carriage adapted to convey the billet, means for tilting the carriage to bring the billet within the yoke, a stop against which the billet slides by reason of the tilting of the carriage, and a hoist for manipulating the billet and yoke to lower it into and take it out of the furnace.

16. In a charging and discharging mechanism for furnaces, a rest within the furnace upon which a billet is adapted to be placed, a yoke surrounding the billet and adapted to remain in the furnace during the heating of the billet, furnace walls including a furnace covering having an opening for insertion and withdrawal of the billet, a closure for the opening carried by the yoke and adapted to be in closed position when the yoke and the billet are in the furnace, and a hoist for the yoke in line with the rest and the opening.

17. A heating furnace of pit type having an opening in the top and having side and bottom walls and a working space between the same, a pair of spaced downwardly inclined rail-like guides adjacent the working space and at their top cooperating with the opening, engaging and directly supporting longitudinal sides of a billet, which is adapted to slide down the guides, rest on the guides during heating and then slide up the guides during withdrawal, a slidable yoke having an open interior and surrounding the billet while the billet rests on the guides, and

a hoist above the opening in the top and connected to the yoke to move the same up and down the guides while the yoke lifts thebillet and the billet is supported on the guides, the

yoke remaining in the furnace working space with the billet during heating.

18. A heating furnace of pit type having an opening in the top and having side and bottom walls and a working space between the same, a pair of spaced downwardly inclined rail-like guides adjacent the working space and at their top cooperating with the opening, engaging and directly supporting longitudinal sides of a billet, which is adapted to slide down the guides, rest on the guides during heating and then slide up the guides during withdrawal, a slidable yoke having an open interior, resting on and guided by the guides during sliding and surrounding the billet while the billet rests on the guides, and

a hoist above the opening in the top and con- I nected to the yoke to move the same up and down the guides while the yoke lifts the billet and the billet is supported on the guides, the yoke remaining in the furnace working space with the billet during heating. V

19. A heating furnace of pit type having an opening in the top and having side and bottom walls and a working space between the same, a pair of spaced downwardly inclined rail-like guides adjacent the working space and at their top cooperating with the opening, engaging and directly supporting longitudinal sides of a billet, which is adapted to slide down the guides, rest on the guides during heating and then slide up the guides during withdrawal, a slidable yoke having an open interior and surrounding the billet while the billet rests on the guides, a tilting mechanism for supporting and inserting a billet in the open interior of the yoke longitudinally aligned with the same when the yoke is in raised position and for supporting and withdrawing a billet from the open interior of the yoke, and a hoist above the opening in the top and connected to the yoke to move the same up and down the guides to a position cooperating with the tilting mechanism while the yoke lifts the billet and the billet is laterally supported on the guides, the yoke remaining in the furnace working space with the billet during heating.

20. A heating furnace of pit type having an opening in the top and having side and bottom walls and a working space between the same, a plurality of pairs of individually spaced downwardly inclined rail-like guides spaced along the working space and at their top cooperating with the opening, engaging and directly supporting longitudinal sides of individual billets, which are adapted to slide down the guides, rest on the guides during heating and then slide up the guides during withdrawal, a slidable yoke for each pair of guides having an open interior and surrounding the individual billet while the billet rests on the particular pair of guides, a carriage movable along the outside of the furnace adjoining the side of the opening in the top to positions cooperating selectively with different pairs of guides, a tilting mechanism on the carriage for supporting and inserting a billet in the open interior of an one of the yokes longitudinally aligned with the same when the yoke is in raised position and for supporting and withdrawing a billet from the yoke, and a hoist above the opening in the top and adapted to connect with any one of the yokes to move the same up and down its guides while the individual yoke lifts its billet and the billet is supported laterally on the guides, the yoke remaining in the furnaceworking space with the billet during heating.

21. A heating furnace of pit type having an opening in the top and having side and bottom walls and a working space between the same, a pair of spaced downwardly inclined rail-like guides adjacent the working space and at their top cooperating with the opening, engaging and directly supporting longitudinal sides of a billet, which is adapted to slide down the guides, rest on the guides during heating and then slide up the guides during withdrawal, a slidable yoke having an open interior and surrounding the billet while the billet rests on the guides, a cover for the opening mounted on the yoke and movable therewith and a hoist above the opening in the top and connected to the yoke to move the same up and down the guides while the yoke lifts the billet and the billet is laterally supported on the guides, and to lift and lower the cover, the yoke remaining in the furnace Working space with the billet during heating.

LEON BIDWELL ROSSEAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 66,305 Crookes July 2, 1867 1,011,266 Sundh -1 Dec. 12, 1911 1,066,312 Page July 1, 1913 1,084,376 Sykes Jan. 13, 1914 1,555,139 Mossa Sept. 29, 1925 1,773,049 Lobley Aug. 12, 1930 1,858,499 Hathway May 17, 1932 2,014,296 Rosenberg Sept. 10, 1935 2,297,447 Albrecht Sept. 29, 1942 FOREIGN PATENTS Number Country Date 310,209 Germany Feb. 21, 1918 489,970 Germany Jan. 24, 1930

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