US3123874A

US3123874A - Metal casting apparatus

Info

Publication number: US3123874A
Authority: US
Priority date: 1958-03-17
Publication date: 1964-03-10
Anticipated expiration: 1981-03-10
Also published as: NL123039C; ES247936A1; DE1268319B; GB912744A; FR1218995A; NL237185A; CH375846A; BE576793A; GB912742A; US3036348A

Description

March l0, 1964 R. w. HAzELETT ETAL 3,123,874

' METAL CASTING APPARATUS original Filed March 1T, 195e e sheets-sheet 1 @MHA/QD Haga. 77' @y ma ffm/f vif/M ATTORNEYS March 10, 1964 R. w. HAzELl-:TT ETAL 3,123,874

METAL CASTING APPARATUS ATTORNEYS March 10, 1964 R. w. HAzl-:LETT ETAL 3,123,874

METAL CASTING APPARATUS Original Filed March 17, 1958 6 Sheets-Sheet 3 MINVENTORS @5er WML/A3? HAZELEI'T BY un firm? 750g-C ATTORNEYS March 10, 1964 R. w. HAZELETT ETAL 3,123,874

METAL CASTING APPARATUS e sheets-sheet 4 Original Filed March 17. 1958 INVENToRs 05567' W/L/AM HAZELE/'f /P/C/HED HAZELET' ATTORNEYS NNN March'lO, 1964 R. w. HAZELETT ETAL 3,123,874

A METAL CASTING APPARATUS orglginal Filed March 17, 1958 6 Sheets-Sheet 5 FIG. 5.

ST. s i mn Z Z 5 NLT R EE .rO A* ,i|- L E L H H WM@ .M n 2/7@ 2m +R` mv, ,y f mi i; 3 0f@ MT m w m .a W A -illl f B w 5 m. C...

March 10, 1964 R. w. HAzELETT ETAL 3,123,874

METAL CASTING APPARATUS 6 Sheets-Sheet 6 Original Filed March 17, 1958 INVENTORS HAZELEI'T @lc/IARD HHZELETT United States Patent Office 3,123,874 Patented Mar. 10, 1964 3,123,874 METAL CASTlNG APPARATUS Robert William Hazelett, Burlington, Vt., and Richard Hazelett, Rocky River, hio, assignors to Hazeiett Strip-Casting Corporation, Fairfield, Conn. Original appiication Mar. 17, 1958, Ser. No. 722,005, now Patent No. 3,036,348, dated May 29, 1962. Divided and this application May 17,. 1961, Ser. No. 115,850

12 Claims. (Cl. 22-57.4)

This invention relates to machines and processes for casting metal strips directly from molten metal and more particularly for continuously casting metal strips between spaced parallel portions of a pair of flexible metal belts which are moved along with opposite surfaces of the strip being cast.

The invention is described as embodied in the structure and operation of a continuous strip-casting machine in which the molten metal is fed into a casting region between opposed parallel portions of a pair of moving flexible metal belts. The moving belts coniine the molten metal between them and carry the molten metal along as it solidies into a strip between them. Spaced rollers having narrow ridges support and drive the belts while holding them accurately positioned and aligned as they move along so as to produce metal strip of high quality and having good surface qualities. The vast quantities of heat liberated by the molten metal as it solidiiies are withdrawn through the portions of the two belts which are adjacent to the metal being cast. This large amount of heat is withdrawn by cooling the reverse surfaces of the belts by means of rapidly moving substantially continuous lms of liquid coolant travelling along against these surfaces.

It is an object of the present invention to provide apparatus for continuously casting metal strip of high quality directly from molten metal.

It is an object of the present invention to provide apparatus for continuously casting metal strip directly from molten metal enabling the operator quickly and easilyv to adjust for casting strip metal of various widths and thicknesses as may be desired.

Among the many advantages of the illustrative embodiment of the invention described herein are those resulting from the fact that the moving belts are accurately supported and steered while being maintained under high tension so as to produce metal strip smoothly and continuously of the desired width and thickness.

Among the further advantages of the machine described herein are those resulting from the fact that the steering action of the belts is accurate and is positive in action by skewing the axis of one of the main rolls at one end of each carriage with respect to the axis of the main roll at the opposite end or" the carriage. Moreover, this skewing motion is readily and accurately produced and controlled in spite of the high tension in the casting belts which exerts a large force on these main rolls. The bearing at one end of each skewed roll is held fixed and the bearing at the other end is supported on a slide which is linked to an eccentric. By twisting the eccentric this slide is caused to move as desired to control the position of the bearing.

The illustrative embodiment of the present invention enables much greater widths of metal strip to be continuously cast than have been made heretofore, and the casting belts are of much greater width. However, the operator may, from time-to-time wish to cast a strip which is not as wide a-s the full width of the belts. This use of very wide belts, and particularly the casting of narrower strip on wider belts results in a condition which we call cold-framing of the belts. That is, the center portions are heated along the full length of the belts and expand from heating while their edges are cooler and do not expand so much. Because of this dilerential expansion across the belt width the center portions lose their tension and become slack compared with the taut edges. The tendency thus is to form scallops or flutes extending longitudinally along the center of the belts while the edges appear to form a at cold-frame. For the purpose of preventing cold-framing by providing a lateral tension to the belts so as to maintain them iiat by stretching the belt edgewise, we nd it to be advantageous to use very slightly reverse-crowned rolls at opposite ends. That is, the center portions of the rolls are of slightly less diameter than the ends. For example, with a belt 46 inches wide the ends of the main rolls may advantageously measure about 0.005 of an inch more in diameter than their centers. This reverse crown imposes an extreme tension on the very edges of the belt adjacent to the main rolls causing the two edges of the belt to bow out slightly away from each other so as to maintain the center under lateral tension so as to prevent formation of longitudinal scallops due to cold-framing.

In this specication and in the accompanying drawings, are described and `shown metal casting apparatus embodying this invention and various modifications thereof are indicated, but it is to be understood that these are given for purposes of illustration in order that others skilled in the art may fully understand the invention and the manner of applying the apparatus in practical use so that they may modify and adapt it in various forms, each as may be best suited to the conditions for casting a particular metal or alloy.

The various features, aspects, and advantages of the present invention will be more fully understood from a consideration of the following description of continuous strip casting apparatusincorporating the invention, considered in conjunction with the accompanying drawings, in which:

FIGURE l is a perspective view of a continuous stripcasting machine embodying the present invention as seen looking at the input end (molten bath region) of the machine from a position adjacent to the control panel, which is positioned near one corner of the reservoir tank for the cooling liquid. For convenience of illustration the box for the molten metal and the pour distributor which feeds the molten metal down into the bath region are omitted from this View;

FIGURE 2 is a perspective view of this machine as seen looking at the output end, and showing the control panel;

FIGURE 3 is a longitudinal elevational sectional View taken along a plane perpendicular to the axes of the various rolls and with parts shown partially broken away for clarity of illustration;

FIGURE 4 is a cross sectional view of the machine taken along the line 4-4 of FGURE 3 looking toward the input end;

FIGURE 5 is an enlarged sectional View of the upper downstream roll and of the adjacent catcher and gutter assembly for catching and removing the cooling liquid which shoots out above the top of the roll along the inner surface of the upper beit after rushing up and around from beneath the roll;

FIGURES 6A and B are diagrammatic exaggerated views of the lower belt illustrating the method and operation of the beit steering mechanism;

FIGURE 7 is an elevational view of the lower carriage belt steering mechanism which operates by moving one of the bearing pillow blocks of the lower upstream pulley so as to skew very slightly the axis of the pulley for steering the belt; and

FIGURE 8 is a partially cut away cross sectional view taken generally along the line 8-8 of FIGURE 7 look- 3 ing toward the left and showing details of the steering mechanism.

General Description In this example, as shown in FIGURE 3, the molten metal is supplied from a pouring box 2 made from heat insulating material. The incoming metal is smoothly and uniformly released beneath the surface of the existing molten pool or bath B, which is maintained during operation.

From the bath B the molten metal is carried into the casting region formed between the opposed surfaces of upper and lower

flexible casting belts

20 and 22, respectively, and generally indicated at C (please see FIG- URE 3). These casting belts are formed of flexible and heat resistant sheet metal having a relatively high tensile strength, for example, conventional cold-rolled low-carbon sheet steel having its ends welded together with both surfaces at the weld being ground smooth and flush to form a continuous wide band or belt having a smooth outer or front surface operates very well. The belts are relatively wide and thin, for example, of the order of 46 inches in width and, for example, having7 a thickness lying in the range from 0.015 to 0.035 of an inch. This illustrative system operates very well with belts having a thickness of 0.025 of an inch. The two belts are supported and driven by means of upper and lower carriages, generally indicated at U and L, respectively.

These two casting belts are driven at the same linear speed. During operation these belts are held under a high tension, for example, such as 10,000 to 12,000 pounds of tension force are exerted by the main end rolls on each belt for a belt 46 inches wide, as shown. The belts are supported, that is, backed up so that their opposed front surfaces are held planar and uniformly spaced over the length of the casting region C. The molten metal is solidified between the casting belts by withdrawing heat through them by means of liquid coolant 24 (FIGURES 1 and 2) supplied into numerous nozzle and

header assemblies

23 and 25 from a reservoir tank 26 extending beneath the machine.

As shown in FIGURE 2, the liquid coolant 24 is drawn from the reservoir 26 through a large conduit 27 feeding to a large capacity centrifugal pump (not shown), for example, such as a double-suction, single stage centrifugal pump having a capacity of 3,000 gallons per minute and driven by a 75 horsepower motor. This liquid is returned through a flexible coupling conduit 29 to a coolant supply main 31 (please see FIGURES 1 and 4) which extends along the rear of the machine and feeds coolant into the various nozzle and

header assemblies

23 and 25 and also to other headers. Because of the large quantities of coolant being pumped, it is desirable to avoid any sharp bends in the conduit or supply main. The pump is positioned as close to the side of the tank 26 as convenient and then a large radius sweeping curve feeds up into the flexible coupling 29.

The upper carriage U can be raised further away from the lower carriage or lowered down closer to the lower carriage so as to cast strips of various thickness. The width of the strip being cast is determined by the spacing between a pair of moving side dams 2S and 30 which run between the respective edges of the casting belts in the casting region (please see also FIGURE 4) and also is determined by the spacing between a pair of stationary side dams 32 and 34 (please see FIGURE l) in the bath region which are associated with the respective moving

side dams

28 and 30. This spacing between these sets of dams is readily adjusted so as to change the width of cast strip.

One of the advantages of the present apparatus is the ease with which adjustment is made to produce strips of different widths. The upper ends of the stationary dams 32 and 34 are adjustably held by a pair of

clamps

60 and 62, respectively. Each clamp includes a pair of grooved slides 64, as indicated in FIGURE 1, which run along lateral ways 66 formed by the opposite edges of the upper flange of an I-beam 65. These ways 66 are machined so as to be square edged and truly parallel. To lock these clamps in position, the operator tightens the clamping screws 67 which are anchored in the edges of a vertical bracket having a pair of slots in its upper end so as to permit vertical adjustment of the free end of the stationary dam which is locked to these slots by clamping bolts 70 (as shown also in FIGURE l).

As mentioned in the introductory portion of the speciiication, the molten metal solidilies between the upper and

lower belts

20 and 22. During this solidication tremendous quantities of heat are liberated per unit weight of strip being cast because, in addition to cooling the molten metal down to its freezing point, its heat of fusion must be removed as it solidities, and then cooled further before discharge from between the belts.

In order to give the reader an impression of relative size it is noted that in this example the total distance in FIGURE 3 from the point beneath the nip roll 44 A at which the upper belt 22 iirst straightens out after passing under this roll over to the point beneath the upper downstream main roll 73 at which the upper belt iirst begins to curve up around this roll is 4 feet and 1 inch. The total distance from the point at which the lower belt 20 rst straightens out after passing around the lower upstream roll over to the point at which the lower belt begins curving down around the lower downstream roll 82 is a total distance of 6 feet 5 inches.

In order to provide tremendous cooling capacity to these planar portions of the belts, substantially continuous high speed lms of coolant are created and maintained flowing along at high speed against their respective reverse surfaces.

In order to isolate the upper and lower belt carriages U and L from any stresses imposed on the framework of the apparatus such as may occur during transportation, installation, or over periods of time, there is an advantageous three-point cantilever support system.

As seen in FIGURES l, 2, 3, and 4 the main framework of the apparatus includes a pair of columns 188 and 139 near the input and discharge ends, respectively. A top beam 190 spans across between the upper ends of these columns, and it has a downward inclination corresponding to that of the casting region C. As seen in FIG- URE 4 this top beam 190 is formed by a pair of spaced back-to-back channel members 191 and 192, which are rigidly fastened together by pairs of plates 193 and 194 (FIGURE l) and braced by pairs of diagonals 195 and 196 (FIGURE 3). A hoist plate 197 (FIGURE 1) is secured to the column 188 between the diagonal braces 195, and other hoist connections (not shown) are provided near the corners of the machine inside of the tank 26 near the bottom. As seen best in FIGURES 3 and 4 a sill I-beam 198 spans between the

columns

188 and 189 and is parallel with the top beam. This sill beam is braced from underneath by diagonal members 199 and 200er which extend down to the bottom of the tank adjacent to the foot of each of these columns.

The lower belt carriage L which supports and operates the lower belt 22 includes a pair of parallel long narrow rectangular frames 200 extending between opposite ends of the main lower rolls Si) and 82. As seen most clearly in FIGURES 1 and 2 these main lower rolls have short projecting

shafts

201 and 202 which are journaled in bearings carried by pillow blocks 203 and 204 at each end of each frame 200. Each frame 200 includes a longitudinal upper frame element 206 carrying the back-up rollers and

cooling header assemblies

23 and 25 and includes a longitudinal lower frame element 208. In order to prevent racking of the lower carriage, an X-frame formed by a pair of angle irons 209 and 210 (FIGURES 3 and 4), extends across between the longitudinal elements 20S, with a wide thick plate brace forming the bottom of a gutter 129 and providing additional strength.

This lower carriage is suspended solely by means of a pair of spaced, parallel inverted T-shaped cantilever arms 212 and 214 (FIGURE 3) which extend across the width of the lower carriage passing between the upper and lower longitudinal elements 266 and 208. It will be noted in FIGURE 4 that the ends of the X-frarne 209 and 210 are secured to the lower flanges of these cantilever arms at 215 and 216.

These cantilever arms 212 and 214 are each supported at a point where they rest on top of the sill beam 198, as seen in FIGURE 4, thus providing two points of support for the lower carriage. A third free-floating point of support for the back ends of these two cantilever arms 212 and 214 is provided by a pivoted link 217. The upper end of this link 217 is loosely held by a pivot pin 218 passing through a pair of channels 219 and 220 which interconnect the rear ends of the cantilever arms 212 and 214. A pivot pin 221 secures the lower end of this link to a pair of blocks 222 which are rigidly secured to a second sill I-bearn 223 which runs along the rear edge of the tank 26. This beam 223 is supported at one end by a column 224 (FIGURE l) and at the other end by a column 225 (FIGURE 2).

In order to prevent any racking movement of the cantilever arms 212 and 214 with respect to each other they are rigidly tied together by a large diameter torqueresisting brace 226. This brace 226 is welded to triangular end plates 227 secured to the outer flanges of the cantilever arms and to saddle plates 228 welded to the inner ange of each arm. Thus, it will be appreciated that the lower belt carriage L is rigidly stilfened internally by an X-frarne and a large torque brace and is externally supported at two points by the sill beam 198 and at a third free-floating point by the link 217 which is loosely pivoted at both ends. Thus, the cantilever arms 212 and 214 are advantageously isolated from any motion of the sill beam 223 relative to beam 198 as caused by external forces.

By virtue of the cantilever support, the front side of the lower carriage L is entirely accessible, and the belt 22 and

dams

28 and 30 can be readily slid on and off. The large tension force for the lower belt is applied by a rubbercoated tensioning roller 230 which is operated by a bellcrank 232 and a pressure-operated cylinder and piston 234 secured to the carriage frame 200 by a bracket 236 (FIGURE 2) and pivot pin 237; a similar arrangement is used for tensioning the upper belt.

The upper belt carriage U is generally similar to the lower one except that the two rectangular frames 240 are shorter and higher and have input end members 241 extending up to carry an upper main roll 242 which is located generally above the nip roll 44. The upper downstream roll 78 is carried by a pair of pillow blocks 243, and a rubber-coated belt-tensioning roller 230 is used. Each frame 24) includes a lower longitudinal element 244 carrying the back-up rollers 86V and the nozzle and

header assemblies

23 and 25, and includes an upper parallel longitudinal element 246.

As seen in FIGURE 3, the two end members 241 are held rigidly together by a horizontal and a vertical brace plate 247 and 248. Another wide horizontal brace plate is shown at 249 extending between the longitudinal elements 246 and a second vertical brace plate at 250. These brace plates are all lightened by central circular cut-outs7 as seen in section.

As shown in FIGURE 4 the upper carriage advantageously is supported so as to float entirely free of the framework of the machine by meansof a pivoted link 252 whose lower end is loosely fastened by a pivot pin 253 to a pair of blocks 254 secured to the channels 219 and 220 above the link 217. Also, as seen in FIGURES l, 2, 3, and 4, a large pressure-operated cylinder and piston 255 are supported on the channels 191 and 192 of the top beam 190 by means of a pair of trunnion pivots 2,56 and 257. A piston rod 258 extends down from the cylinder 255 and is connected by a pivot 259 to a pair of parallel links 260 so as to support the upper carriage U. In this way the upper carriage is quite isolated from stresses in the framework.

In order to hold the two carriages in proper alignment with each other, there are a pair of

upstanding guide rods

262 and 264 rigidly secured to the frames 200 of the lower carriage by pairs of brackets 265 and 266. Corresponding pairs of brackets 267 and 268 are secured to the frames 240 of the upper carriage and slidingly engage these guide rods. These rods are canted at an angle to the vertical so that they are perpendicular to the plane of the casting region C. The upper ends of these rods are loosely held in a bracket 269 which is connected to the top beam 190 so as to isolate the guide rods from the framework. Thus, the guide rods maintain alignment of the carriages as the upper carriage is raised or lowered and in spite of external stresses imposed on the apparatus.

To raise and lower the upper carriage, a lever 270 of the thrid-class is provided, projecting into the upper carriage. The slotted front end of this lever straddles a bracket 271 and is pivoted thereto by a pin 273. This bracket extends down from between a pair of heavy transverse members 272 which are secured to both frames 240 and thus supports the upper carriage. A fulcrum for this lever 270 is established at the remote end by a pivot pin 274 passing through the upper end of the floating link 252. The supporting force is applied to the center portion of this lever 270 by a roller pin 276 passing through the lower ends of the two parallel pivoted links 260 and freely engaging the lower edge of the lever, and thus providing further isolation between the lever 270 and the top beam 190.

In operation the spacing between the upper and lower carriages is provided by a series of precise spacing stops 278 which fit into sockets along the upper edges of the frame elements 206 and engage against the underside of the frames of the upper carriage. When it is desired to cast a thicker or thinner strip the upper carriage is raised and the moving edge dams and spacers 278 are correspondingly changed.

The cantilever support of upper carriage U provides ready accessibility to the casting region merely by raising the upper carriage and enables the upper belt to be quickly and easily slid off and replaced if desired.

Belt-Steering System In order to steer the lower belt 22, as shown in perspective in FIGURES 6A and 6B, the axis of the upstream roll is twisted slightly with respect to the axis of the roll 82. This twisting of the roll axis is accomplished by sliding the front pillow block 203 up and down slightly with respect to the frame 200. When the front end of the axle 201 is raised, as shown in FIGURE 6A, then the upper flight of the belt 22 approaches the roll 82 slightly olf-center from the rear side of the carriage as indicated by the very small angle at 280. This causes the belt to progress slowly along the roll S2 toward the rear side of the machine as indicated by the arrow 281.

When the front end of the axle 201 is lowered, as illustrated in FIGURE 6B, then the upper flight of the belt 22 approaches the roll 82 off-center from the front by a very small angle 282 and it then creeps toward the front as indicated by the arrow 283.

The upper belt is steered in a similar fashion except that it is the downstream roll 78 which is used as the active steering agent. It will be noted from a close study of FIGURE 5 that the upper belt 20 diverges slightly from the upper surface of the slab being cast after'it passes under the last back-up roller 86 so as to provide a clean ance of about I; of an inch beneath the roll 78. Thus, the front end of this roll can be raised or lowered slightly for steering without jamming it down against the slab being cast.

In the operation of the lower belt steering mechanism as illustrated in greater detail in FIGURES 7 and 8, the front pillow block 203 is secured by screws 284 to a movable plate 25 which can be slid up and down a total distance of approximately 1/s of an inch along a at bronze bearing plate 286. This bearing plate 286 is held rigidly 1n place by screws 287 engaging an end frame member 288 which extends up and down between the ends of the longitudnial elements 206 and 208. Because the belt 22 is under a tension of 10,000 to 12,000 pounds, the movable plate 285 presses tightly against the flat bearing plate 286, and thus a very precise but powerful action is required to effectuate the steering.

In' order to slide the plate 285 up or down along the bearing plate 286, there is a pressure-operated cylinder and piston 290 (please see FIGURE l) held at one end by a pivot 291 and a frame bracket 292. The piston rod 293 is pivotally connected by a clevis 294 to a steering arm 295 whose upper end is locked by a key 296 to an operating shaft 297 projecting eccentrically from a journal 298 held in a bearing sleeve 299 within the frame member 288. A corresponding operating shaft 300 projcgt eccentrically from the opposite end of the journal In operation the steering arm is swung back and forth between the position shown in full lines in FIGURE 7 and its other position shown in dashed lines at 295. A pair of

stop bolts

302 and 303 limit the movement of the steering arm 295. As the steering arm moves from the stop 302 over toward the other stop 303, the journal 298 turns within the sleeve 299 so that the two

shafts

297 and 300 move upwardly because of their eccentric positions, and vice versa. This up and down movement of the

eccentric shafts

297 and 300 is transferred to the slidable plate 285 by means of a pair of pivotally mounted

swing links

305 and 306 which straddle the end frame member 288 and have their lower ends pivotally mounted on the opposite ends of a manually adjustable eccentric, generally indicated at 308. The center portion of this eccentric 308 is journaled in a hole 310 in the lower end of the slidable plate 285 and is locked in the desired adjusted position by a set screw 311. The purpose of this manually adjustable eccentric 308 is to set up the desired limits of steering movement for the pillow block 203 when the apparatus is first being put into operation, and thereafter it is usually not necessary to change this adjustment. A pair of flats are formed on the projecting end 312 of this eccentric 308 to provide purchase for a wrench.

It will be noted that the

stop bolts

302 and 303 are held in the swing plate 305 as being a convenient location adjacent the steering arm 295.

The steering mechanism for the upper belt has corresponding reference numbers for it is similar to that for the lower belt, except that it is located at the downstream end. The only other difference as seen in FIGURE 1 is the position of the

stops

302 and 303 which are engaged by a lower end of the steering arm 295 extending down beyond the eccentric shaft. This arrangement of the stops is more convenient on the upper carriage.

In order to control the steering mechanisms, solenoidoperated air valves regulate the compressed air which is fed to the two cylinders 290. Electric switches control the solenoids in accordance with changes in the positions of the rear edges of the two belts. The rear edge of each belt is engaged by a sensitive position-responsive element or probe, such as engaging the upper belt 20 and operating a switch (not shown) on the opposite side of the protective panel 316.

The reason that the probe is located at the input end of the belt 20 rather than being at the output end near the movable roll 78 is to provide a sensitive indication of actual belt position without responding directly to the lateral shift of the belt near the roll 78 as the axis of the roll 78 is being shifted from time-to-time during steering. For similar reasons, the probe (not shown) for the lower belt 22 is located at the output end of the machine (please see FIGURE 2) and operates a switch behind the protective panel 318.

Slight Reverse Crownng of Main Rolls To Prevent Cold Framing of Belts As mentioned in the introduction the

main rolls

242, 78, and 82 have a reverse crowning of 0.005 of an inch, that is, their diameter at their ends is slightly larger than the diameter at the center. A conical taper runs from the center of these rolls out to both ends. This reverse crowning places the edges of the belts under greater tension than the centers and results in a tendency to roach the two edges so that they pull laterally away from the centerline of the belt to maintain the center portion of the belt flat. This effect can be visualized by taking a long rectangular piece of paper and pulling in opposite directions along one of the long edges, this edge will be seen to bow out or roach, thus pulling outwardly from the centerline of the rectangle.

As indicated in FIGURE 6B, the excessive tension at the edges of the belt as they leave the

rolls

80 and 82 tends to distribute itself inwardly at points further removed from these rolls, thus producing arcuate lines of

action

320 and 321 for this tension effect. These arcuate lines of action pull outwardly as indicated by the arrows 323 so as to hold the belt at and prevent any longitudinal scalloping or uting due to cold framing effects.

These rolls have a diameter of approximately one foot, and we find that a reverse crowning in the range from 0.002 up to 0.018 of an inch caii be used, depending upon the thickness and the length of the belt. Longer, thinner belts can utilize more reverse crowning than shorter, thicker ones. Generally speaking, the value of 0.005 works very well for a 46-inch wide belt which is 0.025 of an inch thick and operating on a carriage having a length of approximately 4 to 6 feet.

As shown most clearly in FIGURES 2 and 3, the belts 20 and 21 are driven at an adjustable speed by means of a 2-H.P. electric motor 322 coupled through a variable speed reducer 324 to a sprocket chain 326. This chain passes around a fixed sprocket 328 and engages suitable sprockets xed on the shafts of the

rolls

78 and 82. An automatic spring-loaded chain tensioner and sprocket is shown at 330. With this drive arrangement the upper belt can always be driven regardless of the elevation of the upper carriage.

As used herein the following word is intended to have the following meaning: Strip is intended to include an elongated plate or slab having substantial width and thickness as well as thin, narrow slats.

From the foregoing it will be understood that the continuous strip casting apparatus of the present invention described above is well suited to provide the advantages set forth, and since many possible embodiments may be made of the various features of this invention and as the apparatus herein described may be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and that in certain instances, some of the features of the invention may be used without a corresponding use of other features, all without departing from the scope of the invention.

This application is a division of our copending application, Serial Number 722,005, led March 17, 1958, now matured into Patent Number 3,036,348.

We claim:

1. Apparatus for casting strips of metal directly from molten metal in a casting region between rectilinear portions of a pair of moving flexible metal bands and for steering said bands comprising a first metal band, rst means supporting said first band for longitudinal movement along a first predetermined path a portion of which is substantially rectilinear including a first roll at one end of the rectilinear path portion around which the first band is flexed land including tensioning means for the first band, a second metal band, and second means supporting said second band for longitudinal movement along a second predetermined path a portion of which is substantially rectilinear and positioned in parallel spaced relationship with said rectilinear portion of said first path, said second means including a second roll at one end of the second rectilinear path portion around which the band is flexed and including tensioning means for the second band, first and second bearing means movably supporting a respective end of each of said first and second rolls, said rst and second bearing means being movable in a direction perpendicular to the rectilinear path portions of said first and second bands, first and second eccentrics coupled to said respective bearing means, first and second poweroperated mechanisms for turning said eccentrics t-o move the respective ends of said rolls, and belt-position sensing means engaging an edge of each belt for controlling the power-operated mechanism.

2. Apparatus as claimed in claim 1 and wherein each belt-position-sensing means is near the opposite end of the casting region from the respective roll controlled thereby.

3. Apparatus as claimed in claim 2 and wherein the respective movable rolls are located at opposite ends of the casting region.

4. Apparatus as claimed in claim 1 and wherein each of said eccentrics is coupled to the respective bearing means by a swing link having two ends, one end of the swing link rotatably engaging the eccentric and the other end of the swing link being pivotally connected to the bearing means.

5. Apparatus as claimed in claim 4 wherein the pivotal connection between the bearing means and each swing link includes a manually adjustable eccentric for adjusting the range of movement of the respective bearing means.

6. In a machine of the type in which molten metal is cast against a planar portion of an endless flexible belt, means for supporting and steering the belt comprising a frame, rolls near opposite ends of the frame around which the belt is flexed, said belt having a planar portion extending between said rolls, bearing means carrying one end of one of said rolls, slidable supporting means extending generally perpendicular to said planar portion of the belt and slidably supporting said bearing means, an eccentric having two eccentrically positioned cylindrical portions, one of said cylindrical portions being rotatably coupled to the frame and the other being rotatably coupled to the slidable supporting means, power-operated mechanism for rotating said eccentric, and belt-position sensing means engaging one edge of the belt for controlling said power-operated mechanism.

7. Apparatus as claimed in claim 6 wherein said one cylindrical portion of' the eccentric is journaled in the frame and the other cylindrical position of the eccentric is coupled to the slidable supporting means by an intervening swingable link and a manually adjustable eccentric having a first cylindrical portion journaled in said slidable supporting means and a second eccentrically-positioned cylindrical portion rotatably engaging the swing link.

8. Apparatus for continuously casting molten metal against a portion of a wide, flexible endless, moving metal belt which is intended to be maintained planar in the said portion against which the metal solidities comprising a wide flexible endless metal belt, and a plurality of rollers around which said belt is flexed, at least one of said rollers being positioned at one end of said portion of the belt and having a slight reverse crown thereon with the diameter at the ends slightly larger than the diameter at the center by an amount in the range from 0.002 of an inch to 0.018 of an inch, thereby to maintain the central region of said portion of the belt fiat in spite of the heating effect of the solidifying metal.

9. Apparatus as claimed in claim 8 and wherein each end of said reverse-crowned roller has a conical taper, each taper extending from a respective end into the center of the roller.

10. In apparatus for continuously casting molten metal against a planar portion of a wide, flexible, endless, moving metal belt, means for maintaining said portion of the belt planar to prevent sagging thereof resulting from the heating action on the central region of said portion of the belt caused by the metal being cast, comprising first and second rolls at opposite ends of the planar portion around both of which the belt is flexed, both of said rolls having a slight reverse crown thereon with the diameter at the ends of both of these rolls exceeding the respective diameters at the centers thereof by an amount in the range from 0.002 of an inch to 0.018 of an inch.

1l. In apparatus for continuously casting molten metal in a casting region defined between portions of first and second wide, flexible, endless moving metal bands and wherein said portions of the casting bands are moving in spaced relationship on opposite sides of the casting region, means for maintaining said portions of the bands flat against a tendency to warp as caused by the heating action of the metal being cast comprising first and second rolls each having a diameter slightly larger at its ends than at its center by an amount in the range from 0.002 of an inch to 0.0018 of an inch, said first roll being positioned at one end of said portion of the first band and said second roll being positioned at one end of said portion of the second band, guide means flexing said bands around said rolls, and tensioning means for placing said bands under a large tension stress, and drive mechanism for moving said bands, whereby the edges of said bands in said portions thereof are placed under a larger tension than the central region in .said portions, thereby maintaining said portions of the bands flat.

l2. In apparatus for continuously casting molten metal in a casting region defined between rectilinear portions of first and second wide, flexible endless moving bands and wherein said portions of the casting bands are moving in spaced relationship along opposite sides of the casting region from one end of the casting region toward the other end thereof, means for steering said bands during the casting operation comprising first and second rolls, said first roll being positioned near an end of the casting region and having the first band curving partially therearound, said second roll being positioned near an end of the casting region and having the second band curving partially therearound, stationary bearing means supporting one end of said first and second rolls, movable bearing means supporting the other respective ends of said first and second rolls, movable mounting means for said movable bearing means arranged to move in a direction perpendicular to the rectilinear portions of .said first and second bands, first and second eccentrics coupled to said respective mounting means, first and second power-operated mechanisms for turning said eccentrics for moving said mounting means, and control mechanism sensing the lateral positions of said bands for controlling the action of said power-operated mechanisms.

References Cited in the file of this patent UNITED STATES PATENTS 2,640,235 Hazelett June 2, 1953 2,904,860 Hazelett Sept. 22, 1959 2,914,957 Johnson Dec. l, 1959 2,925,168 Lorig Feb. 16, 1960 OTHER REFERENCES U.S.S. Lorig Alignor Rolls And Pulleys, paper Lorig presented before annual convention AISE, Sept. 26, 1950. (Copy on file in Division 18, 198-202.)

Claims

1. APPARATUS FOR CASTING STRIPS OF METAL DIRECTLY FROM MOLTEN METAL IN A CASTING REGION BETWEEN RECTILINEAR PORTIONS OF A PAIR OF MOVING FLEXIBLE METAL BANDS AND FOR STEERING SAID BANDS COMPRISING A FIRST METAL BAND, FIRST MEANS SUPPORTING SAID FIRST BND FOR LONGITUDINAL MOVEMENT ALONG A FIRST PREDETERMINED PATH A PORTION OF WHICH IS SUBSTANTIALLY RECTILINEAR INCLUDING A FIRST ROLL AT ONE END OF THE RECTILINEAR PATH PORTION AROUND WHCIH THE FIRST BAND IS FLEXED AND INCLUDING TENSIONING MEANS FOR THE FIRST BAND A SECOND METAL BAND, AND SECOND MEANS SUPPORTING SAID SECOND BAND FOR LONGITUDINAL MOVEMENT ALONG A SECOND PREDETERMINED PATH A PORTION OF WHICH IS SUBSTANTIALLY RECTILINEAR AND POSITIONED PARALLEL SPACED RELATIONSHIP WITH SAID RECTILINEAR PORTIN OF SAID FIRST PATH, SAID SECOND MEANS INCLUDING A SECOND ROLL AT ONE END OF THE SECOND RECTILINEAR PATH PORTION AROUND WHICH THE BAND IS FLEXED AND INCLUDING TENSIONING MEANS FOR THE SECOND BAND, FIRST AND SECOND BEARING MEANS MOVABLY SUPPORTING A RESPECTIVE END OF EACH OF SAID FIRST AND SECOND ROLLS, SAID FIRST AND SECOND BEARING MEANS BEING MOVABLE IN A DIRECTION PERPENDICULAR TO THE RECTILINEAR PATH PORTIONS OF SAID FIRST AND SECOND BANDS, FIRST AND SECOND ECCENTRICS COUPLED TO SAID RESPECTIVE BEARING MEANS, FIRST AND SECOND POWEROPERATED MECHANISMS FOR TURNING SAID ECCENTRICS TO MOVE THE RESPECTIVE ENDS OF SAID ROLLS, AND BELT-POSITION SENSING MEANS ENGAGING AN EDGE OF EACH BELT FOR CONTROLLING THE POWER-OPERATED MECHANISM.