US2631343A - Continuous casting machine - Google Patents

Description

March 17, 1953 J. L. HUNTER 2,631,343

CONTINUOUS CASTING MACHINE Filed May 17, 1950 5 Sheets-Sheet l IN VEN TOR.

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CONTINUOUS CASTING MACHINE Filed May 1'7, 1950 5 Sheets-Sheet 2 J25 INVENTOR.

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5 Sheets-Sheet 3 J. L. HUNTER CONTINUOUS CASTING MACHINE March 17, 1953 Filed May 17, 1950 M m W II r 2, fl m1 5 4 a w M y f g w 'I/II/II/l/II/l/II///I/////I/I/////////// will/Ill),11/0/1////1102/fill/1011111100 87 1 f3 w a w flu w o J 1 a Z 1 W March 17, 1953 J. L. HUNTER CONTINUOUS CASTING MACHINE 5 Sheets-Sheet 4 Filed May 17, 1950 iii/7W 5% March 17, 1953 J. L. HUNTER CONTINUOUS .CASTINGHMACHINE 5 Sheets-Sheet 5 Filed May 1'7, 1950 IN VEN TOR. /oism Z Mwrm BY J 4. GENT Patented Mar. 17, 1953 CONTINUOUS CASTING MACHINE Joseph L. Hunter, Riverside, Calif., assignor to Hunter Douglas Corporation, Riverside, Calif., a corporation of Delaware Application May 17, 1950, Serial No. 162,510

9 Claims.

This invention relates to continuous casting machines, and has for its principal object the provision of an improved horizontally arranged machine for the continuous casting of one or more metal bars which may be cut to any desired length. The casting machine of the invention has proved itself capable of producing continuous lengths of cast metal bars that are remarkably free of shrinkage cavities and porosity, and which may be rolled readily to thin gauge strip of high quality. For example, the machine has been used with outstanding success in the continuous casting of aluminum bars approximately one inch thick which have been subsequently reduced by rolling to gauges of 0.010 inch and less for use as Venetian blind strip stock without cracking or the development of surface defects of any substantial character.

In the new casting machine, the mold cavity is defined by a cooperating pair of endless chains of articulated mold blocks, and means are provided for revolving each of said chains about its own center. The chains are mounted so that over a portion of their length they are in engagement one with the other and define between them a mold cavity having Walls which move continuously as the respective chains are revolved together at the same linear speed. Coolant passageways are formed in each of the mold blocks, and coolant is supplied thereto and withdrawn therefrom through rotatable coolant distributors connected to the coolant passageways by lengths of flexible hose or other flexible couplings. Provision is made for rotating each coolant distributor in synchronism with the endless chain of mold blocks to which it is connected by the flexible couplings, whereby a continual stream of coolant may be passed through each mold block at all times during revolution of the endless mold block chains.

The coolant passageways of each alternate mold block on each chain are advantageously connected to the coolant passageways of one of the adjacent intervening blocks, and the rotatable coolant distributor is formed with separate coolant inlet and outlet chambers. Flexible couplings connect the distributor inlet chamber to the coolant passageways of said alternate blocks, and separate flexible couplings connect the distributor outlet chamber to the coolant passageways of the intervening F blocks. Thereby coolant flows from the distrib utor inlet chamber through the coolant passageways of the alternate blocks, then back to the distributor outlet chamber through the coolant passageways of the intervening blocks.

In each pair of mold blocks whose coolant passageways are interconnected, the alternate block (Which receives fresh coolant from the distributor inlet chamber) is advantageously the block that is the last to come in contact with molten metal during each revolution of the chain, and the intervening block (from which coolant is returned to the distributor outlet chamber) is the block which first comes in contact with molten metal during each revolution of the chain. Thereby each block, as it comes in contact with the molten metal, is at substantially a constant temperature determined by the temperature of the coolant.

Molten metal is delivered tothe interior of the traveling mold through aspout of such crosssectional size and shape as to fit closely within the mold cavity. The spout thus forms a plug at one end of the horizontal mold cavity which prevents molten metal from flowing out that end before it has solidified. The spout is advantageously formed at the end projecting into the mold cavity with a central face perpendicular to the axis of the mold cavity and with side faces swept back therefrom at a substantial angle. Passages for conveying molten metal to the mold open to the mold cavity at each of said faces. Thereby molten metal is delivered into contact with the traveling side walls of the mold shortly in advance of the delivery of metal to the center of the mold cavity. In this manner solidification of the molten metal at the sides of the cast bar is caused to occur sufficiently in advance of solidification of metal at the center of the bar so that any shrinkage pipe tending to form at the bar center is kept filled with molten metal delivered through the passage terminating at the central face of the spout.

The solid cast bar of metal emerging from the traveling mold is engaged by a pair of pinch rolls driven (advantageously through an interconnection with the drive for the mold block chains) at a speed just about equal to the linear speed of travel of the mold blocks less the linear rate of thermal contraction of the cast bar between the point of solidification thereof and the point of engagement by the pinch rolls. In this manner the cast bar is relieved of longitudinal stresses which might otherwise cause it to crack or break in the region where its temperature is so close to its melting point as to make it mechanically weak.

The foregoing and other features of the new casting machine are described below in greater detail with further reference to the accompanying drawings, wherein:

Figure 1 is a side elevational view or the entire apparatus for carrying out the casting operation, showing the melting furnace, casting machine, cut-off shears, and the entrance end of a holding oven;

Figure 2 is an enlarged perspective view of the casting machine, as seen from the end into which the molten metal is introduced;

Figure 3 is another perspective view of the casting machine, as seen from the end at which the bar leaves the machine;

Figure 4 is a top plan view of the machine;

Figure 5 is an enlarged sectional view of the same, taken along the line 5-5in Figure 4;

Figure 6 is an enlarged transverse sectional View through the driving end of the up er chain of mold blocks, taken along the line 8-6 in Figure 5;

Figure '7 is a sectional view through one of the mold blocks, taken at l! in Figure 6;

Figure 8 is an enlarged, fragmentary sectional view taken at line 8-8 in Figure 5;

Figure 9 is a perspective view of the feed spout throu h which the molten metal is introduced into the mold cavity;

Figure 10 is a transverse sectional view through the spout, taken at l9ln in Figure 9;

Figure 11 is .a longitudinal horizontal section through the spout. taken at l ||I in Figure 9;

Figure 12 is a horizontal section through two adjacent mold blocks, as seen at l2.|2 in Figure6;

Figure 13 is an eleva'tional view of the driving mechanism at the rear of the machine;

Figure 14 is an elevational view of the mechanism for driving the coolant distributor heads, as seen at Ml4 in Figure 4;

Figure 15 is an enlarged sectional view through one of the distributor heads, taken along the line |5l5 in Figure 4; and

Figure 16 is an enlarged longitudinal vertical section through the flying shear mechanism which cuts the bars off at predetermined lengths, so that the bars can be stored in the holding oven, taken at |6|6 in Figure 4.

Referring first to Figures 1 to 4, the reference numeral 26 designates a melting furnace of the open hearth reverberatory type, which supplies molten metal to a continuous casting machine 22. The casting machine comprises an endless chain of mold blocks which, in the apparatus shown in the drawings, form two traveling mold cavities for the purpose of casting two bars simultaneously. The mold blocks of the machine are cooled by fluid coolant circulated from and back to a coolant'distributor 24. Beyond the casting machine 22 are pinch rolls 26 which engage and drive the bars of metal cast by the machine, and .beyond the pinch rolls is a flying. shear cut-01f 28 that cuts the bars 011 to a predetermined length so that they can be stored in a holding oven 30, or otherwise handled.

The furnace 28 compirses a main housing 3| enclosing the melting hearth, and an external holding well 32 connected therewith, from which the molten metal is drawn through a tap hole, indicated at 33, during operation of the casting machine. The molten metal discharged through the tap hole 33 runs down a channel-shaped launder 34 to a box 35 at the entrance end of the casting machine 22, and thence through two spouts 36 into the two mold cavities of the machine. Both the launder 3d and box 35 are made ofa suitable refractory material to withstand the high temperature of the molten metal. The box,35 is supported on a horizontal shelf 40 which is formed integrally with the supporting structure of the machine, and the launder 34 is secured to the wall or other structure of the furnace well 32 adjacent to the tap hole 33. The box 35 is divided by a partition 4! into two chambers 42 and :83 which feed the two spouts 3B (Figure 4), and these chambers are connected by openings 44 with the channel of .the launder 34 near the bottom thereof, so that the metal fiowing down the launder is admitted to the chambers.

The box 35 rests on a plate 45 which is secured to the top of shelf 46, and is clamped tightly against the rear end of the spouts 36 by means of a screw 46 (Figure 2) which is threaded through a tapped hole in an upstanding flange '50 of an angle bracket 5!, the horizontal flange of which is welded or otherwise secured to the plate'45. The end of screw 6'6 bears against a protective metal plate 52 on the side of launder 34, clamping the latter tightly against the box 35 and holding the box against the ends of the spouts 36. The spouts 36 are themselves connected to a transversely extending, horizontal angle iron 53 (Figure 5) in a manner to be described in more detail hereinafter; the said angle iron 53 being welded or otherwise fixedly attached to the shelf 39.

Referring now to Figures 5 to 8, the casting machine 22 is seen to comprise a pair of endless chains of articulated mold blocks 69, each of said chains being trained around horizontally spaced pairs of drive sprockets 6i and driven sprockets 62, and one of said chains being disposed directly above the other and parallel thereto. The top chain of blocks is designated generally by the reference numeral 63, and the bottom chain by the numeral 64. The two chains are driven in opposite directions by their respective drive sprockets 8!, so that the bottom course of the top chain 63 and the top course of the bottom chain 64 travel together from left to right, as seen in Figure 5, and at the same rate of speed.

Each of the mold blocks 66 is a massive block of hard, dense cast iron or steel, ground on all sides and in the machine as shown, having two shallow channels 55 and 65' (see Figures 2, 3 and 6) formed in the outer face thereof. Each of the channels 65, 85 constitutes one half of the mold cavity for one of the bars of metal cast by the machine, and when the mating blocks of the adjacent courses of the top and bottom chains are brought together in proper registration with one another, they form a pair of laterally spaced, open end mold cavities of uniform cross section that extend longitudinally through the center of the machine. Transverse alignment of the mating mold blocks within extremely close tolerances is obtained by means of small rectangular end plates 61 which are secured by screws to opposite ends of each block in the top chain 63 and project outwardly for a short distance beyond the outer face of the block to form flanges that fit snugly down over the ends of the companionate block in the bottom chain 64. The bottom block is thus confined between the end plates 67, and is prevented thereby from shifting transversely with respect to the top block; hence the two blocks are always maintained in accurate transverse alignment with one another during the period of their conjunction.

As best shown in Figures 6 and '7, each of the mold blocks is provided with a plurality of closely spaced transverse cylindrical bores 66 of small diameter, the said bores lying in a horizontal plane just below the bottom surfaces of the channel 65, 65'. These bores 66 are passages which carry the water or other fluid coolant that removes the heat of the molten metal from the blocks 56, and their connections with the coolant circulating system will be described in detail presently. The passages 65 may conveniently be formed by drillin holes into the block from one end thereof, stopping just short of the far end, and then driving tapered plugs 58 into the open ends of the holes, as shown in Figures 6 and 12.

One thing that should be noted at this point is the close proximity of the fluid passages as to the bottom of the mold cavities E5, as this is an extremely important factor in eliminating any tendency of the block (it to bow upwardly as a result of unequal expansion between the top and bottom sides of the block. The magnitude of the distortion problem becomes immediately evident when it is realized that during operation of the machine, the channels as, are filled with molten metal (e. g. molten aluminum at 1250 F.

to 1400 F.), whereas the opposite side of the block may be at only to F. By placing the coolant passages 55 as close as possible to the bottom of the channels 65, 65', the mass of metal heated by the molten metal is reduced to the minimum, and the rate of heat transfer to the coolant is accelerated due to reduction of metal thickness through which the heat must travel. In order to counteract the expansive force of even the small mass of metal lying above the passages 66, it is desirable to provide a large mass of metal on the opposite side of the passages, which remains cool, and therefore is relatively unaifected by the heat of the aluminum, and to. this end the underside of the block 59 is pro- I vided with an integral massive transverse rib or buttress E0 of solid metal which reinforces and stiffens the block against bending forces.

The ends of the rib '58 are cut back from the ends of the block 68, as shown in Figure 6, to provide space for chain (or hinge) links Tl which connect the blocks together to form the endless chains 53 and E4. The links H are secured by bolts '52 to the underside of the blocks 60, and are staggered on alternate blocks so that the projecting ends of adjacent links interengage by overlapping. These overlapped ends of the links are drilled through to receive pin bolts 13, and the latter extend all the way through fromone side of the block E5 to the other, thereby providing a hinge pin connection for the links at both sides of the block. The pins '13 are located with their centers in the planes of the vertical contact surfaces of the blocks 59 at the front and back sides thereof; thus, when the blocks are i;

traveling in a straight line, adjacent faces of each pair of interconnected blocks are laid fiat against one another, forming an unbroken surface from one end of the straight section of chain to the other.

The ends of the pins 73 project beyond the outer links on both sides, and mounted thereon are ballbearing rollers '54 which run on the peripheral edges of rigidly supported side lates :5. Each of the side plates '55 is elongated horizontally, with straight top and bottom edges and semicircular ends having their centers of curvature at the axes of the sprockets 5i and 62. The side plates 15 of each chain 63, 5 3 are mounted on a supporting structure located at one side of the chain mold assembly, and are attached thereto by a pair of laterally spaced, thick-walled steel pipes E5 of large diameter which project horizontally outward from a side wall plate E9 of the supporting structure so between the sprockets El and 62.

The structure 80 is made up of heavy steel'plates' welded together at their edges to form a closed, box-like member of great strength and rigidity, and is advantageously provided with a base plate iii) that is bolted down to the floor. The pipes threaded stud on which a nut 18 is screwed, and

the latter is drawn up tight against a collar 11 that bears against the outside of the outer sprocket 6i. Each of the driving sprockets BI is rotatably supported by a double row ball bearing 66 and a single row ball bearing Bl mounted respectively at the opposite ends of an eccentric bore within a sleeve 88. The sleeve 88 extends through and is rotatable within aligned circular openings 89 and 90 in the front and back wall '19 and 8!, respectively, of the supporting structure 8i). Sleeve 88 is held against axial and rotational movement with respect to the housing 39 by means of bolts 92 which pass through arcuate slots 93 (see Figure 3) in a radial flange 94 at the end of the sleeve 88 projecting from the side wall plate it. The slots 93 are concentric with the axis of the sleeve 88, and thus'permit a limited amount of rotation of the sleeve, whereby the tension in the chains 63, 54, can be adjusted by virtue of the eccentricity of the shaft 85 relative to the outer surface of the sleeve.

The driven sprockets 62 are likewise fixed to shafts 35' corresponding to shaft 85, and the same are rotatably supported by antifriction bearings mounted within a flanged sleeve 88, one end of which appears in Figure 2. The principal difference between the supports for shafts 85 and 85' is that the latter are fixed in position, and are not provided with the eccentric chain tension adjustment of the former. A spur gear 95 is mounted on the end of the upper shaft 85 where it projects from the back of the supporting structure 80, and is secured against rotation relative thereto by means of a key or the like. A corresponding spur gear 95 is secured to the lower sprocket drive shaft, as shown in Figure 13, which is an elevationalview of the drive mechanism for the casting machine. The top gear 95 is meshed with an idler gear 96, which is meshed, in turn, with another idler gear 91 that is also meshed with the bottom spur gear 95'. The idler 91 meshes with a pinion 98 mounted on a shaft 99, and the latter is driven by a sprocket "19 through a friction clutch I01, which is adapted to slip when overloaded, and thus protects the mold chains and driving mechanism from damage in the event that something becomes jammed.

Idler gear 96 is mounted on a shaft 102, which is journaled in one end of an arm N33. The other end of the arm I03 is swingably adjustable about a journal portion 104 provided on a cap I05 that is bolted to the outer end of the sleeve 88, as shown in Figure 6. The journal portion 104 is concentric with the axis of the top sprocket'drive shaft 85, and the arm I03 thus maintains a constant center-to-center distance between gears 95 and 96, even though the shaft 85 may be swung through an arc during adjustment of the tension of the top chain 63.

Gearr95; is, of. coursaxcarried with. shaft 85 during any'rsuchiad'justment of the latter, and arm.I03 causesgearv 96 to. be shifted with gear 95. Once the. properadjustment of. shaft 85 has been obtained, arm I03 is-rigidly secured to thesupportingstructure 80 by a screw I06 which passes througha slotted hole in the arm and fits loosely therein.

The other idler gear 91 is mounted on ashort stub shaft I01, which is likewise maintained at a constant center-to center distance with respect togearv 95. In this instance, shaft I01 is journaled in an arm I08 intermediate the end thereof. Theright-hand end (Fig- 13) of arm- I08 is supported for swinging movement about the axis of the bottom sprocket drive shaft 85, and shaft 90 is journaled in the lefthand endof the arm. Arm I08 maintains. a constant center-to-center distance between shafts 85, I01, and 99, and also. permits the bottom shaft 85 to move through an arcuate path during. adjustment of the tension of the bottom .chain 64. Here again, when. proper adjustment of shaft 85.has been obtained, arm I08 is rigidly secured to the housing 80 by a screw I09 which passes through a slotted hole in the arm and fits loosely therein.

Trained around the sprocket I is a roller chain IIO which extends downwardly to and is trained around a sprocket I I I mounted on the drive shaft of an electric motor II 2. A second sprocket'I I (Figure 4) on the motor shaft drives another chain II3 which is trained around a large sprocket II4 on shaft II5, to drive the pinch rolls 26. The electric motor I I2 also drives the rotatable heads of the coolant distributor 24, and to this end, a sprocket I is mounted on the bottom drive shaft 85, which drives a chain I2I that is trained around another sprocket I22 on a shaft I 23.

Shaft "I23 extends forwardly through the supporting'structure 80 (as shown in Figure 3) and is'journaled at the other end in a pillow block I24 (Figure 14) mounted on one vertical edge of a housing I25 that supports the coolant distributor mechanism 24. As shown in Figure 14, a sprocket I26 on shaft I 23 drives a chain I30 Whlch'is trained around sprockets I 3! and 132, and also around an idler sprocket I33. The purpose of the idler sprocket I33, is to enable the chain I30 to be carried around one side of sprocket I32 and around the opposite side of sprocket I3I, so that the'two sprockets are driven in opposite directions. Sprocket I3I drives the upper distributor head I34 of the unit 24, while sprocket I32 drives the lower distributor head I 35' thereof The housing I25 is preferably'constructed of steel plates welded together to form a box-like structure having a'base plate- I40 that is bolted to the floor. The housing I25 is'also connected to the supporting structure 80 of the casting machine by two heavy steel bars MI and I42 (Figure 3) which locate the distributor heads I34 and I35 centrally between the ends of the upper andlower chains 63 and 64.

Fixedly mounted in opposite side walls of the housing I25 are sleeve bushings, such as that shown at I43 in Figure 15, and journaled for rotation'. in these bushings are pipes I44 and I45 to Figure- 15, although it will be. understood that the description applies also to the lower unit. Sprocket I3! is secured to pipe I44 near one end thereof, .and Welded to the other end on the op' posite side of the housing I25 isa closed, cylindrical drum I (see particularly Figure 15), which is divided by a partition I5I into two chambers I52 and I53. Extending through the center of pipe I44 is'a smaller pipe I54 one end of which passes through an opening I55 in partition I5I and thus communicates with chamber I53. Leakage through the clearance between pipe I54 and opening I55 is prevented by two O-ring seals I56.

Mounted on the other end of the pipe I44 beyond the sprocket I3I, as best shown in Figures 1 and 4, is a swivelled fluid coupling I50 which connects a water supply pipe I5! to the inner pipe I54, and a fluiddischarge pipe I52 to the annular space between pipe I54 and the walls of pipe 144. The fluid supply pipe I5I is con nected to a pipe I53 which is connected, in turn, to the output side of a water pump E54 driven by a motor I55. The intake side of the pump I54 is connected by a pipe I56 to a tank I15 near cold water is discharged close to the suction end of pipe 555, whereby a certain portion of the cold water is taken directly into the pump I54, while the balance is mixed with the warm water discharged by pipes 452. An overflow pipe I12 emptying into a drain (not shown) is connected into the tank I10 near the upper end thereof, and warm Water is thus allowed to. escape at the same rate that cold Water is added. A valve I13 in line I1I permits adjustment of the rate of flow of cold water into the tank I10, so that the proportion of newly added cold water to the total volume of water being circulated through the mold blocks canbe regulated over a wide rangeto give any desired water temperature.

The water delivered by pump I54 is discharged into the innerpipe I54, and (see Figure 15) emties into chamber I53 of the distributor drum I 50. A plurality of equidistant, angularly spaced elbow fittings I14 corresponding in. number to one-half of the number ofmold blocks 50 of the upper or lower chain blocks, as the case may be, are screwed into the drum I50 so that they communicate with chamber I53. The elbow fittings I14 are connected by lengths of flexible hose I15 (Figures 2 to 4) to nipples I16 (Figure 6) projecting laterally from the adjacent ends of alternate blocks '55. As Ibe's t shown in Figures 6, 7 and 12, each nilpple I15 is screwed into a tapped hole 5 85, which intersects another hole I 8| at right angles thereto and at a slightly higher level. Hole I8I, in turn, intersects the bores 55 extending transversely across the mold block, and thus serves as a manifold to distribute the water or other fluid coolant uniformly to all the coolant bores 55 therein.

At the opposite end of each block, the bores 66 are again intersected by a cross hole I82 which is intersected, in turn, by a tapped hole I83 extending. into the block from the end thereof. Both of the holes I8I and. I82 are conveniently formed by drilling holes into the block 60 from the leading or trailing edge thereof; the said holes being stopped just short of the distant edge, and being tapped at their open ends to receive a tapered pipe thread plug I19, as shown in Figure '1. A threaded elbow nipple Hi l is screwed into the tapped hole I83, and clamped to the nipple is a short, U-shaped flexible hose 585, which eX- tends inwardly toward the center about which each endless chain revolves in its travel alon the periphery of the plate 15, the other end of said hose being connected to another elbow nipple I86 in the next adjoining block 50 as shown in Figure 12. The construction of all of the blocks is identical, and water passed through one block, say the right-hand block in Figure 12, and discharged through nipple I84 and hose I85 is therefore returned through the adjoining block (i. e. the left hand block as seen in Figure 12) to another nipple I95, which is connected by a return length of flexible hose I9I to one of a second set of elbow fittings I92 (Figure 15) on the distributor head. The elbow fittings I92 are screwed into the drum I55 on the left-hand side of partition II, and therefore are connected into chamber I52. In this way, fluid returning from the mold blocks is sent back through the space between pipe I54 and pipe I-lt to the swivel joint I60, where it is emptied into tank I10 through line I62.

The cooperative operation of the chains of mold blocks and the distributors described above is as follows: When the motor II2 (Figure 13) is energized, the mold block drive gears 95 and 55 are rotated in opposite directions, thus turning the upper and lower sprockets 6| (Figure 5) in opposite directions so that the upper and lower mold block chains 53 and 64 revolve in opposite directions about the geometric centers of their respective supporting side plates 15. The upper chain of mold block 63 revolves in a counterclockwise direction, as viewed in Figure 5, and the lower chain of mold block 54 revolves at the same speed in a clockwise direction. Thus a moving mold traveling at a constant speed (to the right as viewed in Figure 5) is defined between the engaging mold blocks on the lower course of the upper chain 53 and on the upper course of the lower chain 64.

As the endless chains of mold blocks are revolved, the distributor heads 134 and I (Figure 3) are driven in synchronism therewith by the shaft I23, which is operatively connected to the driving mechanism of the mold block chains. As described above, the sprocket I3I (Figure 14) through which the upper distributor is rotated turns in the opposite direction to the sprocket I34 through which the lower distributor I35 is rotated. The size of these sprockets (and of the other sprockets in the distributor drive) are so chosen that the distributors each make just one complete revolution for each complete revolution of the chains of molds blocks about their respective geometric centers. Thus the upper distributor I34 (Figures 2 and 3), which is connected by one set of hoses 515 and I5] to the upper mold block chain 53, rotates in the same direction as and substantially in synchronism with that chain, and the lower distributor I535 rotates in the same direction as and substantially in synchronism with the lower block chain 64 to which it is connected by the lower set of hoses I15 and I9I. The distributors are positioned so that their axes of rotation lie respectively on projections of the axes of revolution of the mold block chains 63 and 64.

As the chains of mold blocks revolve, the coolant distributors rotate with them, permitting the flexible coolant hoses I15 and I9I to be carried continuously around and around with the mold blocks to which they are connected. In this manner a continual stream of coolant is enabled to flow from the distributors I35 and I35 through the mold blocks of the respective chains 63 and 54 and back again to the respective distributors, without the hoses either becoming entangled with one another or interfering in any way with revolution of the mold block chains.

One important factor that should be brought out at this point is that each pair of mold blocks connected together by the U-shaped hose section I85 is connected to its associated distributor head I34 or I35 so that the water is circulated first through the trailing block of the pair, and then is returned to the distributor head through the leading block of the pair. The advantage of this arrangement is that a high degree of uniformity of temperature is obtained at the mold block encountered by the molten metal issuing from the feed spout, regardless of whether it is the leading or trailing block of an interconnected pair. This is due to the fact that at the instant the leading block moves into position to receive the molten metal from the feed spout, the water circulating through the passages 66 is at the same temperature as the water entering the trailing block, since the latter will not yet have been heated up by the hot metal. Thus, if the temperature of the water entering the trailing block is 60 F., it will still be at 60 F. when it enters the leading block (the cavities of which are now filled with molten metal) on its return trip to the distributor. As the trailing block of the pair moves into position to receive the molten metal, it will of course still be at 60 F., and from this it will be evident that the walls of the mold cavity will always be at a relatively uniform temperature at the instant of contact by the molten metal. The maintenance of uniform mold block temperatures is important, because the grain structure and other physical characteristics of the metal are greatly influenced by the rate at which the metal is chilled. Thus, a temperature difference between adjoining blocks would result in objectionable variations in grain size and structure along the length of the bar. The importance of maintaining an absolutely uniform mold block temperature diminishes after the metal has been initially chilled, and any slight temperature difierential between the trailing and leading blocks as the mold blocks continue their travel through the machine has no apparent ill effect on the bar cast by the machine.

The feed spouts 35 by which molten metal is fed into the traveling mold assembly are shown in detail in Figures 9, 10, and 11, and each is seen to comprise a centrally bored, two-piece body I95 of insulating refractory material enclosed within a rectangular, box-like steel case I95. Projecting from one end of the case is a tip I51 of insulating refractory material, which is shaped to conform closely to the cross sectional contour of the mold cavity, but is provided with clearance on all sides to permit free movement of the mold blocks past the same. The length of the feed spout is governed by the position of the terminal end of the tip I91 within the mold cavity. In order to prevent molten metal from escaping through the crack between adjacent blocks as the latter come together after passing around the sprockets 62, it is necessary that the tip I91. project into the "between them. to the blocks 2I9,*the spout is solidly held in assists .1 l moldcav-ityto a point not less than 1 block width beyond the centerline of the sprockets 62.

The case I 96 comprises side plates I 98 to which top and bottom plates I99 and 290 are secured by countersunk screws 20I. The top plate I99 is somewhat shorter than the bottom plate 299, and formed in the inner faces of the exposed end portions of the side plates I98 are vertically extending notches 282 which receive tongues 293 projecting laterally from opposite sides of the tip I91 at the base end thereof. The tip I9? is thus keyed to the side plates of the'case by a tongue and groove connection, and is conveniently inserted into the case or removed therefrom by "merely slipping the back end of the tip down into the open notches 202. Metal cheeks or lands 2M are secured by screws to'the outsides of the side plates I 98 at theextreme ends thereof, and these are contoured to fitthe sides of the mold cavity. The cheeks 2% provide solid backing for the extreme outer edges of the tip I91, and protect the latter against breakage or excessive abrasion in the event that the spout becomes slightly misalined within the mold cavity.

At the rear end of the case I96, the top, bottom, and side plates have vertical notches 205 formed therein'to receive keys 206 that flt into notches in the inside faces of two laterally spaced blocks 2 Ill. The blocks 2 I I] are welded or otherwise fixed "to the top of angle iron 53, and are spaced apart just far enough to receive the rear'end of the case With the case thus keyed place, and the box 35 can be clamped tightly against the rear ends of the two spouts, as described earlier.

The refractory body I95 of the feed spout is preferably made of two pieces for convenience in removing the solid plug of metal that freezes in the passages 2II each time that the machine is shut down. The passages 2II extend longitudinally through the body I95 from one end to the other, and may be drilled out, as shown in Figure 10, or formed in any other suitable manner. The

.rear end of the body I95 projects slightly beyond the end of the metal case I96, and terminates in a perfectly square, fiat face 2 I2 which abuts against the outside of the box 35, with the passages 2 I I registered with openings 2 I3 (Figure 5) in the box, through which the molten metal flowsfrom the box into the spout.

The extreme outer end of the tip I9? is preferably formed as shown in Figure 11, with a center ,face 2I4 perpendicular to the axis of the spout, and two outwardly facing, slightly concave faces '2I5 that are swept back at an angle of about 35 to the face 2I4. Three outwardly diverging passages 2I6 are formed in the tip; one going to each of the three angularly related faces.

'The purpose of this tip configuration is to promote freezing of the metal at the sides of the mold first, so that the shrinkage cavity that tends to form in the cast bar as the metal solidifies and cools can be fed and filled by molten metal issuing from the center pasage 2H3. The water-cooled mold blocks chill the metal so suddenly that freezing of the molten metal occurs almost instantaneously, and the bars are probably solid all the way through, although somewhat mushy in character, within a very short distance from the tip. The progressive freezing of the bars from the sides in toward the center that is obtained with the tip just described, enables the fluid metal discharged from the middle passage to keep full the shrinkage cavity that -would otherwisebe-likely-to form, until the center of the bar finally solidifies,- and as a result the bars produced by the machine are sound and entirely free'of'shrinkage pipes and porosity.

One highly important feature of the. invention has to do with the manner whereby the tip I91 acts to seal the back end of the mold cavity against leakage of molten metal. As mentioned earlier, the tip I91 is shaped to conform closely tothe cross sectional contour of the mold cavity, and is provided with clearance on all sides to permit free movement of the mold blocks past the tip. This clearance may range from a few thousandths of an inch up to ,4, or more, and the highly fluid, molten metal under a head of several inches in the box 35, has a tendency to fiow into the same. However, the cold mold blocks extract heat "so-rapidly from the molten metal in'the comes viscous or'slushy, with a thin skin formed on its surface'whichprevents penetration of the metal into the crevice between the tip I91 and the mold-blocks.

As the mold blocks'move away from the tip, the skin is ruptured; and fluid metal flows back into the corner, where it is again chilled and another skin formed on the surface. This process is-repeated with-great rapidity'all of thetime that the machine is in operation, producing'a faintly rippled surface on the bars; each ripple 'mold blocks isprevented, and at the same time,

a sealing action is obtained that prevents the molten metal-from flowing into the clearances.

On leaving the machine at the exit endthereof, the barsof metal are-guided laterally into the pinch rolls 2B between outer rollers 22!) and tandem inner rollers 22I (Figure v4) .which are *rotatably supported on .a horizontal shelf 222 projecting laterally from 1 the supporting .structure 80. The pinch rolls 26 comprise an upper -roll' 223 and a lower roll .224 whichextend transverse to the direction of travel of the cast bars, and whichare rotatably. supported at their ends in bearing blocks "225. The bearing blocks 225 are slidable vertically between laterally spaced pairs of guide posts 226, which are mountedon a horizontal shelf plate 230 projecting laterally from the side of the supporting structure 80, the top ends of eachpair of posts being connected together by abridge -member 23L Long bolts 232 extend upwardly through the shelf .230, guide posts 226, and bridge member 23I to secure the side frames intoa solidstructure. An adjusting screw 233 is threaded downwardly through the bridge member'23I and engages the top bearing block 225 to adjust the spacing between the rolls 223, 224.

The bottom-roll 224 is connected at its back end to the sprocket shaft II5 (Figure13) and is driven thereby in the clockwise direction, as viewed inFigure 5; the top roll 223 being driven by the'bottom roll in the opposite direction and at the same rate of speed through a pair of inter- As best -shownin Figures -3 -and '5, "the two rolls 223, 224 are water cooled, and to this end are provided with cylindrical bores 235 (Figure through Which a pipe 236 of somewhat smaller outside diameter is passed. Fitted on extensions of the roll necks and pipes 236 beyond the gear housing 234 are swivel couplings 240 which, deliver water to the inner pipe 236 and exhaust the water from the space between the pipe and the walls of the bore 235. The inlet sides of the couplings 24s are connected to pipes 24! which are joined together and connected to the main water pipe I11; while the outlet side of the couplings is connected to a pipe 242 (Figures 1 and 3) that returns the used water to the tank H0.

The rolls 223 and 224 have two important functions: First, they are driven at a speed carefully computed to regulate the speed of the bars to the linear speed of the chains 63, 64, less the linear rate of thermal contraction of the cast bars that has taken place between the point in the machine where the metal becomes solid and the point of contact of the rolls 223, 224; and second, they perform the work of pushing the bars into the holding oven 36, thereby relieving the chains 63, 64, of this relatively heavy load. The first-named function is important because of the low tensile strength of most metals at temperatures near the melting point. Aluminum, for example, is characteristically hot short at temperatures just below its melting point. and in the hot-short temperature range the tensile strength of the metal is substantially zero. The rapid cooling of the metal in the casting machine causes a very considerable amount of shrinkage in the bar, and if the bar is allowed to leave the mold blocks at the same speed as the linear travel of the chains 63, 64, the lengthwise shrinkage of the bar within the mold cavities of the machine will cause the bar to pull apart or at least crack, in its weak, hot-short zone. The pinch rolls 223, 22 hold back on the bar so that the amount of shrinkage is taken up, and the exit speed of the bar from the machine is somewhat less than the linear speed of the chains 63, 52. The proper peripheral speed of the pinch rolls is obtained by proportioning the sprockets lid and H6 so that a rotational speed is obtained which is correct for the diameters of the rolls 223 and 224.

The second-named function is important where long lengths of bar have to be pushed into the oven. In such instances, the work required to overcome friction of the bar sliding over its supports within the oven may exceed the pushing capacity of the casting machine, since the ma chine has only the friction of the mold blocks on the bars to drive the latter, and in that case the mold blocks would merely skid along the bars. The pinch rolls 223, 224 may be tightened down onto the bars by the adjusting screw 233 to secure a powerful frictional grip thereon.

As the bars leave the pinch rolls, they are engaged on their outer edges by two guide rolls 256 (Figures 3 and 4) which are supported on a narrow shelf 25f projecting laterally outward from the supporting structure 80 at the extreme end thereof.

Beyond the guide rolls 256, the bars pass through the flying shear cut-01f 28, where they are automatically cut to predetermined lengths while continuing in motion. The flying shear cut-off (best shown in Figures 3 and 16) is essentially a hydraulically operated shear mounted on a freely movable carriage that is adapted to travel with the bars while the latter are engaged by the shear blades. The carriage for the shearing mechanism comprises two side plates 252 which are bolted at their bottom ends to bosses on opposite sides of a vertically disposed cylin der 253. Near their upper ends, the side plates 252 are bolted to a cross bar 254, and bolted to the underside of the cross bar is a stationary shear blade 255, the cutting edge of which is designated at 256. Rotatably mounted on the outside of each of the side plates 252 at the leading and trailing edges thereof are two wheels 25!] that run on laterally spaced pipe rails 26l. The rails 26I are supported at their ends on posts 262, and are preferably inclined very slightly downhill toward the casting machine so that the carriage tends always to return by gravity to the end of the track adjacent the pinch roll unit 26.

A piston 263 is slidably disposed within the cylinder 253, and secured to the top end of the movable piston is a plate 264. Welded to the top of the plate 264 is a transversely extending bar 265, and bolted to the top surface thereof is a movable shear blade 266, the cutting edge of which is designated at 261. The bar 265 and shear blade 266 are engaged at their ends between pairs of spaced, parallel guides 210 which are welded to the side plates 252, said guides holding said movable shear blade to a vertical path of travel such that the edge 261 passes the stationary cutting edge 256 in a shearing relationship.

During the shearing operation, the bars are clamped firmly against the underside of the stationary blade 255 by means of a clamping plate 211 which is slidably supported on three laterally spaced guide rods 212 that are screwed into the plate 264; only one of said guide rods being visible in Figure Hi. The plate 211 is pressed upwardly against heads 214 at the top ends of the rods 212 by springs 213, and in this upperlimit position, the top surface of the plate is flush with the top surface of the movable shearing blade 266. The three guide rods 212 are located so that the two bars pass between them; the center rod being between the bars, and the end rods being on the outer sides thereof. Reces'ses 215 are provided in the bottom surface of the stationary shear blade 255 to receive the heads 214 when the piston is at the top of its stroke.

Fluid under pressure is admitted to the bottom of the cylinder 253 through a flexible hose 226, which is connected to a hydraulic pump (not shown). The fluid is discharged into the cylinder when a limit switch (not shown) at the far end of the oven 50 is engaged and closed by the ends of the bars of metal that are being fed into the oven. Closing of this switch actuates a solenoid-operated by-pass valve on the hydraulic pump, causing the fluid discharged by the pump to be directed through the hose 216 into the cylinder, and as the fluid pressure builds up within the cylinder, the piston 263 moves upwardly, carrying the clamping plate 211 and shearing blade 266 with it.

As the bars are engaged and clamped against the shearing blade 255 by the plate 2H, and as the edge 261 begins to bite into the metal, the carriage is carried along the rails 26! with the bars. Shearing is usually completed within a second or two, and the top surface of one of the sheared bars then engages and depresses a plunger 286 projecting downwardly throughv a hole in cross bar 25.4v from a switch 28;! mounted ontop. of the cross bar. Switch 28 i is a normally-v closed. switch connected serially into the circuit of the solenoid on the by-pass valve, and is opened when plunger 28% is depressed, thereby restoring the by-pass valve to its, original position and allowing the fluid, in the bottom of the cylinder to escape. The switch 28.! is protected from damage by a shield 2,1,9 having end plates 218 that are bolted to. the side plates 2.52, of the carriage. As the piston 263 drops down to the bottom of the cylinder, the bars are released, and the carriage is, freed to roll back to its original position.

The holding oven 38 forms no part of the present invention, and is merely included in the drawings. by way of illustration. Accordingly no description of the oven is deemed necessary, other than to mention that the bars are fed into the oven through a flared throat 282 (Figure l).

The mold cavity channels 65., 85' are wiped clean and lightly oiled on each circuit. of the chain by means of oiling pads 235 and 285 (Figures 2 and 3) on the top of the machine. These pads are preferably of felt, and are attached to metal holders 290 which are swingably supported from transversely extending rods 2! that are attached to the top of the supporting structurev 8B. Torsion springs 292 holdv the pads down against the surfaces of the mold blocks.

The operation of the casting machine isv believed to be self-evident from the foregoing description. When the machine is first started up, the openings ZIS in the box 35 through which molten metal flows into the spouts 36 are blocked oif, and the furnace is tapped. Molten metal is allowed to fill the chambers 42 and 43, and to overflow through a notch 283 in the side of, the box, running down a gutter 284 into pig molds, until the launders 3d and box 35 have-been thoroughly heated and the temperature of the metal in the box is right for casting. The passages 2J3 arethen uncovered, and metal is allowed to flow through the spouts 35 into the mold cavities. The mold: cavities are usually plugged with a block so as to prevent the metal from flowing along the mold cavity until the latter has been filled, These blocks are carried through the machine on the front ends of the bars, and drop off when the bars push out of the machine at the exit end thereof; While the speed of the machine depends upon a number of variables, I have found that the most satisfactory operation for, aluminum alloys is obtained with a chain speed of approximately feet, per minute.

When the machine is to be stopped, thetap, hole '33 of the furnace is plugged, and when the chambers 42, 33 have emptied, the keys 2&5 are pulled out, releasing the spouts so that they can travel through the machine with the now-solidified bars. The tips. i 91 are usually destroyed in the process, but. these areinexpensive andare considered ex- 'pendable.

While I have shown and described in considerable detail the presently preferred form of my invention, it will be. understood that the description herein is merely illustrative, and that various changes may be made in the part and components of the machine and in their arrangement relative to each other without departing from the broad scope of the invention as defined in the appended claims.

I claim:

1. Acontinuous casting machine comprising; an endless chain of articulated mold blocks having Cil coolant p s a ay pr v ded. her n. mea s f r revolving said endless chain in a non-circular path, a, rotatable coolant distributor, flexible couplings connecting said distributor with the cool! ant passageways in said blocks, and means for rotating said distributor in synchronism with said endless chain of blocks.

2; A continuous casting machine comprising an endless chain of articulated mold blocks having coolant passageways provided therein, means for revolving said endless chain, means connecting the coolant passageways of each alternate block to the coolant passageways of an adjacent intervening block, a rotatable coolant distributor having coolant inlet and outlet chambers, flexible couplings connecting said distributor inlet chamher to. the coolant passageways of said alternate blocks and connecting the distributor outlet chamber to the coolant passages of said intervening blocks, and means for rotating, the coolant distributor in synchronism with the endless chain of blocks.

3:. In a continuous casting machine, an endless revolvable chain of articulated mold blocks defining a travelling mold arranged to receive a stream of molten metal adjacent one end thereof, said blocks having coolant passageways formed therein, conduits connecting the coolant passageways of adjacent pairs of blocks, a source of coolant, and a, conduit connecting the last of each of said pairs, of blocks to come. in contact with molten metal during each revolution of the chain with said coolant source, whereby coolant from said source flows first through the blocks of each of said pair that are the last to come in contact with molten metal during each revolution of the chain and therefrom flows through the blocks of each pair that are first to come in contact with molten metal during each revolution of the chain.

4. A machine for continuous casting of metal in bar form, said machine comprising a pair of endless chains of articulated mold blocks arranged adjacent one another and cooperating to form a straight mold cavity of uniform cross section, means for driving said chains of mold blocks so that the cooperating blocks thereof forming the mold cavity travel at the same rate of speed and in the same direction, each of said mold blocks having coolant passages provided therein, a source of fluid coolant under pressure, a pair of rotatable coolant distributor heads connected to said source, each of said heads being disposed to one side of and adjacent one of said chains of mold blocks, said heads being driven in the same direction as their respective chains and synchronized therewith, so that each head makes one revolution with each complete circuit of the chain, and conduuit means connecting each of said distributor heads with the fluid passages in the mold blocks of its respective chain.

5. A machine for, continuous casting of metal in barform, said machine comprising a pair of endless chains of articulated mold blocks arranged adjacent one another and cooperating to form a straight mold cavity of uniform cross section, means for driving said chains of mold blocks so that the cooperating blocks thereof forming the mold cavity travel at the same rate of speed and in the same direction, each of said mold blocks having coolant passages provided therein, a source of fluid coolant under pressure, a pair of rotatable coolant distributor heads disposed to one side of and adjacent said chains of mold blocks, each of said heads being provided with inlet and outlet chambers, said inlet chambers being connected to said source of coolant and said outlet chambers being connected to a drain, means for driving said heads in the same direction and at the same speed as their respective chains, whereby each head makes one revolution with each complete circuit of the chain, and conduit means connecting said inlet and outlet chambers of said distributor heads with said fluid passages in said blocks, whereby fluid coolant is circulated through said passages to cool the blocks.

6. In a continuous casting machine of the character described, having an endless chain of articulated metal mold blocks, each block having a channel formed in its outer face, said blocks cooperating so that the channels therein form a continuous mold cavity of uniform cross section, each of said blocks having a plurality of parallel coolant passageways formed therein closely adjacent the bottom surface of said channel, there being a pair of header passageways connecting said coolant passageways together at each end thereof, means for delivering coolant to one of said header passageways and for withdrawing it from the other, and a massive stiffening rib extending from the face of the block opposite that in which the mold channel is formed, said rib being maintained at a relatively constant temperature by the coolant in said passageways, the mass of said rib being substantially greater than the mass of metal lying between said coolant passageways and the bottom of said mold channel, said rib serving to resist the tendency of said mold block to bow outwardly as the metal between said coolant passageways and the bottom of said channel is heated and expanded by the metal poured into the mold cavity.

7. A continuous casting machine comprising a pair of endless chains of articulated mold blocks arranged adjacent one another and cooperating to form a straight mold cavity of uniform cross section, each of said blocks having coolant passageways formed therein closely adjacent the surface of said mold cavity, a coolant distributor comprising a rotatable hollow head associated with each of said endless chains, each of said heads being divided internally by a partition into separate inlet and outlet chambers, coolant circulating means connected to said heads so as to deliver coolant to said inlet chambers and to remove coolant from said outlet chambers. a plurality of flexible coolant pipes connecting the inlet chamber of each of said heads to the inlet sides of the coolant passageways in the mold blocks of the associated chain, a plurality of flexible coolant pipes connecting the outlet chamber of each of said heads to the outlet sides of the coolant passageways in the mold blocks of the associated chain, and motor means for driving said endless chains in opposite directions, and for driving each of said distributor heads in the same direction and at the same rotational speed as its associated chain.

8. A continuous casting machine comprising a .pair of endless chains of articulated mold blocks arranged adjacent one another and cooperating to form a straight mold cavity of uniform cross section, each of said blocks having coolant passageways formed therein closely adjacent the surface of said mold cavity, a coolant distributor comprising a rotatable hollow head associated with each of said endless chains, each of said heads being provided with inlet and outlet hose fittings, coolant circulating means connected to said heads so as to deliver coolant to said inlet fittings and to remove coolant from said outlet fittings, a plurality of flexible hoses connecting the inlet fittings of each of said heads to the inlet sides of the coolant passageways in the mold blocks of the associated chain, a plurality of flexible hoses connecting the outlet fittings of each of said heads to the outlet sides of the coolant passageways in the mold blocks of the associated chain, and motor means for driving said endless chains in opposite directions, and for driving each of said distributor heads in the same direction and at the same rotational speed as its associated chain.

9. A continuous casting machine comprising a pair of endless chains of articulated mold blocks arranged adjacent one another and cooperating to form a straight mold cavity of uniform cross section, each of said blocks having coolant passageways formed therein closely adjacent the surface of said mold cavity, a coolant distributor comprising a rotatable head associated with each of said endless chains and having a plurality of inlets and outlets, a set of flexible hoses connecting said inlets to the inlet sides of the coolant passageways in the mold blocks of the associated chain, a second set of flexible hoses connecting said outlets to the outlet sides of the coolant passageways in the mold blocks of the associated chain, coolant circulating means connected to said inlets and outlets so as to circulate coolant through said hoses and the passageways is said mold blocks, and motor means for driving said endless chains in opposite directions, and for driving each of said distributor heads in the same direction and at the same rotational speed as its associated chain.

JOSEPH L. HUNTER.

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

UNITED STATES PATENTS Number Name Date 342,920 Matthes et a1 June 1, 1886 560,661 Trotz May 26, 1896 1,035,956 Furlow Aug. 20, 1912 1,139,885 Mellen May 18, 1915' 1,139,887 Mellen May 18, 1915 1,157,794 Miller Oct. 26, 1915 1,319,673 Stephenson Oct. 21, 1919 1,870,406 Douteur Aug. 9, 1932 1,997,200 Schumacher et a1. Apr. 9, 1935 2,030,482 Summey Feb. 11, 1936 2,068,835 Wurster Jan. 26, 1937 2,087,824 Tully July 20, 1937 2,127,407 Harbord et a1 Aug. 16, 1938 2,135,183 Junghans Nov. 1, 1938 2,171,132 Simons Aug. 29, 1939 2,521,362 Grausam Sept. 5, 1950

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