US3416594A

US3416594A - Rotary continuous casting machine having resiliently movable sidewalls

Info

Publication number: US3416594A
Application number: US523789A
Authority: US
Inventors: Gyongyos Ivan
Original assignee: Alusuisse Holdings AG
Current assignee: Alcan Holdings Switzerland AG
Priority date: 1965-02-02
Filing date: 1966-01-28
Publication date: 1968-12-17
Anticipated expiration: 1985-12-17
Also published as: BE675811A; GB1071306A; CH426115A; AT259781B; NL6600876A; DE1508961A1

Description

3,416,594 IENTLY l. GYONGYCSS Dec. 17, 1968 ROTARY CONTINUOUS CASTING MACHINE HAVING RESIL MOVABLE SIDEWALLS 3 Sheets-Sheet 1 Filed Jan. 2 8. 1966 INVQNTOR:

l VAN Dec. 17, 1968 GYONGYOS 3,416,594

ROTARY CONTINUOUS CASTING MACHINE HAVING RESILIENTLY MOVABLE SIDEWALLS Filed Jan. 28, 1966 3 Sheets-Sheet 2 MIM HIS ATI'02IVEY INV ENTOR IVAN evoweyos,

Dec. 17, 1968 I. GYONGYQS 3,416,594

ROTARY CONTINUOUS CASTING MACHINE HAVING RESILIENTLY MOVABLE SIDEWALLS Filed Jan. 28, 1966 5 Sheets-Sheet 5 v INVQYTOR NAN QYON GYOS,

HIS AT TORNF Y.

United States Patent 3,416,594 ROTARY CONTINUOUS CASTING MACHINE HAV- ING RESILIENTLY MOVABLE SIDEWALLS Ivan Gyongyos, Liebefeld, Bern, Switzerland, assignor t0 Swiss Aluminium Ltd., Chippis, Switzerland, a corporation of Switzerland Filed Jan. 28, 1966, Ser. No. 523,789 Claims priority, application Switzerland, Feb. 2, 1965,

1,412/ 65 Claims. (Cl. 164-278) ABSTRACT OF THE DISCLOSURE A rotary continuous casting machine has a rotor and side rings and an endless cover band defining a mold groove; the cover band makes contacts with the rings and displaces them yieldingly so that the cover band will be in pressure contact with the surface of a casting while the casting is in the mold.

The invention relates to the art of continuous casting, and relates more particularly to continuous casting machines of the rotary type. In rotary continuous casting machines, the casting mold is formed by a portion of an angular groove that is open towards the exterior, and is formed on a rotating cooled casting wheel or casting drum, and a cover band covers that portion and moves synchronously therewith.

Casting machines of this type are used for the continuous casting of billets, particularly composed of aluminum, aluminum alloys, zinc and copper. In the rotary continuous casting machines developed by Ilario Properzi and built by the firm Continuus, which are usually connected to a multiple rolling mill, there are primarily cast metal rods, for instance of triangular or pentagonal cross section. In the adjoining rolling mill, these metal rods are rolled to become wires of circular cross section, for instance of a thickness of 10 mm. Where the casting mold has a rectangular cross section, however, the resulting casting will be a band or slab that has a width that is far in excess of its thickness.

The instant invention primarily relates to the continuous casting of such metal slabs on [a rotary continuous casting machine.

Reference is had to the copending applications Altenpohl and Gyongyos filed Dec. 13, 1965, Ser. No. 513,506; Gyongyos et a1., Ser. No. 447,651, filed Apr. 13, 1965; and Gyongyos Ser. No. 484,691, filed Sept. 2, 1965.

Rotary casting machines now in use, generally work satisfactorily. They are, however, deficient therein that in the casting mold during the solidification of the metal melt, there appears a shrink gap which widens gradually, so that the casting will for its major part be out of contact with the cover band and may even be out of contact with the casting wheel or casting drum itself. Shrink gaps of this type, however, adversely affect the removal of heat from the casting. Normally, the casting wheel drum is cooled, and the cover band is cooled, and by these instrumentalities heat is removed from the casting, promoting its rapid solidification. Air gaps which are formed by the aforesaid shrinking, on the other hand, constitute insulating layers between the casting and its surroundings, which affect adversely any rapid heat removal. Where the cover band is energetically cooled, such a resistance layer will not be very disturbing, as long as the casting product is a narrow endless slab of pure aluminum or pure zinc; present day rotary continuous casting machines, cast in large quantities slabs of pure aluminum of a width of from 100 to 200 mm.

During the casting of slabs, the shrink gap will, of

Patented Dec. 17, 1968 course, be larger at the narrow sides than at the wide sides; these narrow side gaps, however, usually do not result in any adverse effects.

The shrink gap on the wide sides, on the other hand, is found to be disturbing particularly during the casting of alloys which tend to sweat during solidification. This, for instance, is the case with aluminum magnesium alloys of one (1%) percent magnesium or more, as well as with aluminum zinc magnesium alloys and aluminum magnesium silicon alloys. The sweating is particularly disturbing, as the surfaces of the billets or slabs usually are neither milled nor planed prior to the subsequent rolling. In modern plants, the endless casting band, or slab, that emerges from the rotary casting machine is first passed through a control and regulating equipment and then is passed into the rolling mill that is synchronized with the rotary casting machine.

A brief reference will be made to roll-casting and to casting with a belt-type mold. Roll-casting relates to the continuous casting of endless plates between two rotating rolls (see for instance The Continuous Casting of Steel, Scientific American, New York, Dec. 1963, pp. 75, 76). In casting with the aid of a belt-type mold, on the other hand, the casting takes place between two circulating bands or belts, for instance as practiced in accordance with the Hazelett method (see the aforementioned application of Altenpohl et 211.). With the use of roll-casting and belt-type casting, it has been possible to cast continuously aluminum plates having a thickness of from 7 to 50 mm., and a width of from 800 to 1500 mm. Yet, similar efforts in connection with rotary continuous casting machines, have been unsuccessful to date.

This difference in results is, however, not surprising. During roll-casting, it is not difiicult to maintain a uniform distance between the wide sides of the mold cavity, because the molds are rigid. Also in the case of a belttype mold, it is possible to maintain quite Well the desired thickness throughout the width of the mold cavity, because the belts throughout a straight path remain under high tension between the guiding rolls and the tension rolls; therefore, they cannot draw or vault towards the center of the straight mold cavity, and thus the distance between the wide sides of the mold cavity will remain throughout the entire width practically uniform.

With rotary continuous casting machines, however, different circumstances exist. In fact, conditions are so different, that in the past it had not been possible to cast flawlessly slabs or bands of uniform thickness having a width of about 300 mm. The reason for this is primarily found in the usual arrangement of the casting drum and the casting groove thereon, and the cover band completing the casting mold thereon. The cover band, which is usually a steel band, in constructions heretofore used rests with its edges on two side rings that are rigidly connected to the casting drum and form thereon the side walls of the casting groove. The cover band is suspended and guided by deflecting and tension pulleys.

The casting wheel or casting drum usually comprises a rim which defines an external surface that forms a part of a groove for the casting mold, and side walls. In the interior of the wheel or drum, there is usually provided cooling equipment for the rim. The cooling is customarily carried out by means of flowing or sprayed water. The cover band is often also subjected to cooling, namely near the mold cavity, usually by spraying its external surface with water.

The rim of the casting drum usually is made of a single piece; the side rings, which form the side walls of the mold cavity, are rigidly connected to the main portion of the rim. By this arrangement, the height to which these rings project outwardly beyond the rim, is unchangeable.

Under the tension exerted by the aforesaid pulleys,

the cover band will along the stretch where it forms the wide side of the mold cavity, be pulled at its center section towards the bottom of the mold cavity so that, in a mold having for instance a width of from 400 to 1200 mm., the mold cavity will be much smaller along the longitudinal middle line, than at the sides thereof. Under these circumstances it is not possible to cast plane slabs of the type necessary for rolling into sheet metal.

It is among the principal objects of the invention to provide a rotary continuous casting machine that avoids the drawbacks of the prior art.

It is another object of the invention to provide such a machine, in which the cover band is so guided that, within the region of the mold cavity, it will rest on the casting, thereby preventing the occurrence of any shrink gap on the wide surfaces of the casting. This contact between the cover band and the solidified casting also restrains the inward bending of the cover band into the liquid and into the partially solidified parts of the casting.

It is a further object of the invention to provide such a rotary continuous casting machine in which the side rings are not rigidly connected to the rim of the casting drum or wheel, but are radially movable relative thereto and resiliently journalled, and mounted in such a manner that they are driven in unison with the casting drum, in spite of the aforesaid movable and resilient connection.

It is yet another object of the invention to provide a machine with movable side rings of the type described, which are neither integral with the casting drum or rim nor rigidly connected thereto, and which under the pressure of the cover band yield resiliently. Thus the rings are displaceable in the region of the mold cavity in a direction towards the axis of rotation of the drum, so that the height of these side walls of the mold cavity will gradually become smaller in correspondence to the shrinking of the casting. The resilient yielding of the side rings within the region of the mold cavity avoids the occurrence of any shrink gap parallel of the cover band, not only for slabs, but even for rods.

It is yet a further object of the invention to provide such a machine, in which the mold cavity is -being narrowed in a direction at right angle to the wide surfaces of the casting in correspondence to the progress of the shrinking.

This arrangement has the advantage that the cover band will, within the region of the mold cavity, by the pressure it exerts onto the casting, generate a reaction pressure by the rim. This co-action of pressure and counterpressure has the effect that, in accordance with the instant rotary continuous casting machines for wide slabs, for instance of 400 mm. width or more, the cover band throughout the major portion of the mold cavity no longer can bend or vault towards the rim; the cross section of the mold cavity accordingly will substantially be uniform throughout its width.

With the above and other objects of the invention in view, the invention consists in the novel methods, construction, arrangement and combination of various devices, elements and parts, as set forth in the claims hereof, certain embodiments of the same being illustrated in the accompanying drawings and described in the specification.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary vertical sectional view of a rotary casting machine in accordance with the prior art;

FIG. 2 is a fragmentary vertical sectional view similar to FIG. 1, but showing an embodiment of the instant invention;

FIG. 3 is a fragmentary schematic sectional view showing the general construction of a rotary cont'muous casting machine;

FIG. 4 is a fragmentary schematic sectional view, similar to FIG. 3, but showing a modified construction;

FIG. 5 is a fragmentary schematic sectional view, similar to FIG. 4, showing the preferred embodiment of the instant invention, but omitting for the sake of clarity the molten metal feeding means;

FIG. 6 is a fragmentary large scale sectional view, taken on the line 6-6 of FIG. 5;

FIG. 7 is a large scale fragmentary sectional view showing a modified detail of FIG. 5; and

FIG. 8 is a fragmentary schematic end elevational view, embodying a modification.

In carrying the invention into'etfect in the embodiments which have been selected for illustration in the accompanying drawings and for description in this specification, and referring now particularly to FIGS. 1 and 2, the effect of the instant invention may clearly be gleaned by comparing these views. In FIG. 1, there is shown the occurrence of shrink gaps developed in rotary casting machines of the prior art. FIG. 1 shows such a casting machine of the prior art. A casting rotor 11a is provided, in the instant case a rotary drum that has a rim 11. The rotor 11a rotates in the direction A about its axis of rotation. Above the rotor, there is mounted revolubly a deflecting pulley 10, that revolves in the direction B about its rotational axis. The axes of the pulley 10 and of the rotor are disposed on the same vertical plane. A cover band 12 is guided by the pulley 10 and by another pulley, not shown in FIG. 1. The cover band 12 is endless and is so circulated (see FIG. 3), that a portion of it that is in contact with the peripheral part of the rotor moves synchronously therewith. The mold cavity 16 is formed between the rim 11 and the cover band 12. A tundish 13 feeds the molten metal 14 into the entrance opening 15 of the mold cavity 16. The molten metal begins to solidify at 17 and 18 near the wall of the mold cavity 16. The completely solidified metal is indicated at 19.

As shown in FIG. 1, shrink gaps begin to form at 20 and 21, and become wider at 22 and 23. At 24, the solidified slab 19 again makes contact with the surface of the rim 11, thus discontinuing the lower shrink gap 23. The upper shrink gap 22, however, not only continues, but increases in thickness for an amount that corresponds to that of the lower shrink gap 23, and is due to the latters elimination. The

shrink gaps

22 and 23 form insulation layers filled with air, which are detrimental to a rapid and uniform cooling of the slab 19.

In the rotary continuous casting machine in accordance with the instant invention, shown in FIG. 2, these drawbacks are eliminated. In this view, similar reference numerals have been used as in FIG. 1. After solidification of the casting at 17 and 18, there occurs no shrink gap, because the cover band 12 is pressed in accordance with the arrows C into contact with the outer wide surface 19a of the solidified slab 19.

The elimination of the shrink gap formation offers the advantage of trouble-free casting even with alloys that normally tend to sweat during casting. Furthermore, the increased cooling effect resulting from the lack of shrink gaps, offers advantages for the casting of pure metals as well as of alloys. These advantages include an increased casting speed resulting in a higher production, and the use of a shorter mold cavity permitting the use of a shorter cover band 12. These cover bands, as best shown in FIGS. 3, 4 and 5, are endless bands. They must from time to time be replaced. The shorter the band, the smaller the replacement cost. A shorter mold cavity, furthermore, for instance extending only through about one-fourth of the circumference of the rotor instead of the usual one-half of the circumference, permits a reduction in the number of deflecting and tensioning pulleys from the usual four to three.

In FIG. 3 there is shown a rotary continuous casting machine with four deflecting and tension pulleys 10, 25, 26 and 27. A shorter mold cavity, in accordance with the invention, makes it possible to substitute for the two pulleys 25 and 26 a single pulley 28, shown in broken lines in FIG. 3, providing at the same time for a correspondingly shortened cover band 12.

In FIG. 4, there is shown a rotary casting machine having, in accordance with the invention, a shortened mold cavity 16 that extends only throughout about onefourth of the circumference of the rotor 11a. Three deflecting and tensioning pulleys 10, 28 and 29 are provided which suspend and guide and move the cover band 12 in the usual manner, so that along the mold cavity 16 the cover band 12 will move synchronously with the circumferential speed of the rotor 11a. The roll 30 serves a different purpose and does not participate in the suspensioning of the cover band 12. Water spray nozzles 31 are provided for cooling the cover band 12 near the mold cavity 16, and wipers 32 are provided for guiding away the excess cooling water. Instead of cooling by water, however, cooling may be carried out by blowing air or water vapor onto the cover band 16.

As best shown in FIG. 5, there is provided a rotor 34, for instance a revolving drum, that rotates in the direction A. The rotor 34 includes an annular rim section or rim 42 that has an external annular surface 42a which forms the bottom of a groove, a portion of which forms part of the mold cavity 16. Two rings 33 (see FIGS. 5 and 6) are mounted on the rotor 34 near the annular rim 42 thereof. The two rings 33 are spaced apart from each other on the rotor 34, and each ring 33 is mounted adjacent one side of the rotor rim 42.

The rings 33 project outwardly beyond the external surface 42a of the rim 42 and these radial projections form the side walls of the aforementioned groove and the mold cavity 16.

As best shown in FIG. 5, the rings 33 are eccentrically displaceable on the rotor 34. The axis of rotation of the rotor 34 is indicated at 40, while the common axis of the rings 33, shown displaced in FIG. 5, is indicated at 41. It will be noted, however, that the eccentricity of the rings 33 relative to the rotor 34 and its rim 42 has been exaggerated in FIG. 5. The eccentricity is brought about by pressure exerted by the cover band 38 against the rings 33, as has been indicated in connection with FIG. 2, and as will be explained in greater detail hereinafter. The rings 33, however, are so mounted on the rotor 34, that they are normally in the absence of any external force held resiliently concentrically therewith.

The cover band 38 is suspended on three deflecting and tension pulleys 35, 36 and 37. The pulleys guide the cover band 38 and move it in such a manner that the portion of the cover band 38 that is adjacent the periphery of the rings 33 will be moved substantially in synchronism with the circumferential speed of the rings 33.

The mold cavity 16 extends from its entrance opening 43 to its exit opening 44 throughout about one-fourth of the circumference of the rotor 34. The pulley 35 is mounted near the entrance opening 43 of the mold cavity 16, and the pulley 36 is mounted near the exit opening 44 thereof. The pulley 36, in contrast to the pulley 35, however, is disposed movably, so that it can move in the direction of the arrow 39, for a distance, in correspondence to the extent of shrinking of the slab in the mold cavity 16. The extent of shrinking depends on the metal of the casting, as well as on the casting speed and the temperature.

The mold cavity 16 of FIG. 5, as previously explained, is defined by the external surface 42a of the rim 42, by the outward radial projections of the rings 33, and by the cover band 38. The cover band 38, as best shown in FIG. 6, is in contact with the outer edges 33a of the rings 33 throughout the extent of the mold cavity 16. The radial distance between the rim surface 42a and the band cover 38 varies, in accordance with the invention, in dependence of the thickness of the slab, while the distance w (FIG. 6) between the rings 33 determines the width of the slab to be cast, taking shrinking into account.

In FIG. 5, the means for delivering the molten metal to the mold cavity has been omitted, in order to simplify the drawing. A tundish 13 of the type shown in FIGS. 3 and 4 may be used. Furthermore, there have been omitted from FIG. 5, again for the sake of simplicity and clarity, cooling means for the cooling of the cover band 38 and of the rotor 34. The feeding of the molten metal preferably is carried out in such a manner that the metal level in the tundish will be higher than the lowest point of the pulley 35, so that at the entrance opening 43, the mold cavity 16 will be completely filled with molten metal. In the mold cavity 16, the metal will first be liquid substantially throughout the entire cross section; it forms there, as best shown in FIGS. 1 and 2, the liquid casting head 16a. Thereafter, as the mold continues in its rotation in the direction A, the metal begins to solidify. The thickness of the solidified crust near the walls of the mold cavity 16 will increase rapidly, until the slab will be solidified throughout its cross section.

During the cooling, there will first occur a shrinking due to solidification, and thereafter a shrinking due to cooling. As evident from FIG. 5, that section of the cover band 38 that is in contact with the peripheral edge portions 33a of the rings 33, will exert a pressure in the direction 401: towards the rotational axis. This pressure is due to the positioning of the

pulleys

35, 36 and 37, and of the cover band suspended thereon, relative to the rings 33, and the resulting tension in the cover band 38. Under this pressure, the rings 33 will yield in correspondence to the extent of shrinking, and will be displaced eccentrically, at right angle to the wide surface of the slab in the mold cavity 16. Thus the height of the mold cavity 16 will gradually be shortened due to the shortening of the height of the aforementioned radial projections of the rings 33 beyond the rim surface 42a.

As a result, due to this yielding displacement of the rings 33, and in contrast with machines of the prior art, the cover band 38 will remain in contact with the casting in the mold 16.

As the rings 33, under the pressure exerted by the cover band 38, are displaced in the direction 40a, the rim 42 of the rotor 34 will, contrastingly, exert an opposite pressure in the direction 37a against the slab in the mold cavity, and through the slab onto the cover band 38, preventing the cover band 38 from vaulting transversely against the surface of the rim 42. The distance between the rim 42 and the cover band 38 will be shortened in correspondence to the extent of shrinking, and will be substantially uniform throughout the width of the slab. The resulting slab will at any one cross section have substantially uniform thickness.

Resilient means, such as helical compression springs 45, are provided between the rotor 34 and the rings 33, which urge the rings 33 into the aforesaid normal position concentrically with the axis 40 of the rotor 34. The springs 45 are held in opposite depressions, namely in depressions 46 of the rings 33 and depressions 47 of the rotor 34 disposed oppositely thereto. In FIG. 5, four springs 45 have been shown; it will be understood, however, that the number of springs 45 can be varied, though there will need to be provided at least three springs 45 for each ring 33. It is preferred, however, to employ from four to six springs 45. Instead of helical compression springs, there may be used leaf springs or other conventional resilient means.

The rim 42 has two lateral parallel radial faces 49, and each ring 33 has a corresponding surface 48. The play between each surface 48 of a ring 33 and the respective face 49 of the rim 42 is so dimensioned as to promote an easy sliding of the rings 33 relative to the rim 42, but sufliciently small so that molten metal may not penetrate therebetween.

The distance a between the lower Surface 50 of each ring 33 and the upper surface 51 of the rim 42 (FIG. 6) may be slightly larger than the shrinking gap that occurs during shrinking. At a mold width w (FIG. 6) of from 400 to 1000 mm. and a thickness of slab of from 7 to 25 mm., the aforesaid distance a should not surpass the depth of the shrinking gap for more than 2 mm. Great care should be exercised in dimensioning the structure of the machine, so as to avoid that during a breakdown of the casting operation the cover band 38 would be positioned too close to the surface 42a of the rim 42.

Connecting means are provided to establish a positive driving connection between the rotor 34 and the rings 33, which operative in all positions of the rings 33 on the rotor 34, so that the rings 33 will at all times rotate together with the rotor 34. A preferred embodiment of the connecting means is shown in FIG. 5. Each ring 33 is provided with a plurality of radially inwardly extending noses 52. The rotor 34, on the other hand, is provided with corresponding radially inwardly extending recesses 53, one recess 53 being provided for each nose 52. The noses 52 cooperate with the recesses 53 in the manner of an involute gearing. An involute gearing of this type, as shown in FIG. 5, permits the eccentric displacement of each ring 33 relative to the rotor 34, while retaining a positive driving connection between the rotor 34 and the rings 33. The number of noses 52 may be varied, though at least two noses 52 will need to be provided for each ring 33. In accordance with a preferred construction, there will be provided as many noses 52 as there are springs 45.

Different connecting means may, however, be provided instead. In FIG. 7, the connecting means comprise pins 54 that are disposed in opposite recesses of the rotor 34 and of each ring 33. The recesses in the rings 33 are designated 56. Springs 55 are provided in the recesses 56, and the springs 55 in each recess 56 engage the pin 54.

It may be desirable to arrange the casting machine in such a manner that throughout a predetermined portion of the molding cavity 16 the rings 33 are fixed and unyielding relative to the rotor 34. The purpose of such an arrangement is to avoid thereby that any pressure would be exerted by the cover band 38 onto the casting in the mold cavity 16 while the casting is either still liquid or at least to a large extent still pasty. A construction of this type is embodied in FIG. 5. A pair of rolls 57 is mounted radially adjustably adjacent the peripheries of the rings 33. Each roll 57 may be adjusted to a position where it engages the outer edge portion 33a of one of the rings 33 at a point spaced from the entrance opening 43 of the mold cavity 16 in advance thereof. At that point, the rolls 57 will exert radial pressure against said outer edge portions 33a. These rolls 57 permit a pre-setting of the rings 33 resiliently into a position of predetermined eccentricity relative to the rotor 34, for determining the point of the mold cavity 16 at which, due to the resilient displacement of the rings 33 by the cover band 38, there will commence the exertion of pressure by the cover band 38 onto the slab in the mold cavity. It will be understood, however, that the aforesaid pre-setting means are a further development of the instant invention, but not an absolutely necessary part thereof.

Where it is desired to pre-set exactly the position of the rings 33 relative to the rotor 34, two pairs of take-up rolls may be used instead of the single pair of rolls 57. An arrangement of this type is shown in FIG. 8 and in broken lines in FIG. 6. The first pair of rolls 58 of this type is disposed in the vertical plane of the axes of rotation of the rotor 34 and of the pulley 35. A second pair of rolls 59 will be positioned about midway of the length of the mold cavity 16. The pair of rolls 58 is adjustable radially in opposite directions, as shown at 60, whereas the pair of rolls 59 is adjustable radially as shown at 61, as well as peripherally, as indicated by the arrows 62 and 63. In the illustration of FIG. 6, the take-up rolls 58 have not been shown adjustably. The pairs of take-up rolls 58 and 59 determine the eccentricity of the rings 33. By this radial pre-setting of the rings 33, the distance between the cover band 38 and the rim surface 42a will diminish in the direction A of the casting movement. As previously mentioned, the distance becomes shorter in accordance with the shrinking at right angle to the wide surface of the slab.

In FIGS. l5, rotary continuous casting machines are shown, in which the metal is fed to the machine near the top of the rotor. It is possible, instead, to arrange the mold cavity, and to position the pulleys, in such a manner that the metal is fed into the mold at an incline, or vertically, downwardly or at an incline, or vertically, upwardly. For the upward feeding, there will need to be provided closed feeding nozzles, for instance as used for roll casting by the Hunter Engineering Company (see for instance E. Herrmann, Handbuch dcs Stranggiessens (Handbook for Continuous Casting) p. 542, Aluminium Verlag G.m.b.l-l., Dusseldorf, 1958). Lastly, the metal may be fed horizontally to the lower ortion of the rotor.

The rotor may be made of metal having high heat conductivity, for instance copper or aluminum alloy. In rotary continuous casting machines, however, it may be advantageous to make the rings of an inferior heat condoctor, for instance stainless steel.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent, is as follows:

1. In a rotary continuous casting machine:

the combination of a rotor including an annular rim,

two .rings mounted with relation to said rotor, spaced apart from each other, a ring being positioned adjacent each side of said rim, said rings forming radial projections extending outwardly of said rim and terminating in outer edge portions and defining with said rim an annular groove open towards the outside, a cover band moving substantially synchronously with said outer edge portions throughout a portion of said groove and defining with said groove portion a continuous casting mold having entrance and exit end openings, guiding means operable for guiding said cover band in pressure contact with said outer edge portions throughout said portion of said groove, means operable for delivering near said entrance opening molten metal into said continuous casting mold, a

said rings being eccentrically displaceable relative to said rotor,

resilient means urging said rings into a normal position concentrically of said rotor,

said cover by its contact pressure displacing along at least a portion of said continuous casting mold said rings eccentrically against the power of said resilient means to shorten the height of said projections outwardly of said rim, thereby maintaining contact between the cover band and the surface of the casting in the mold, and

connecting means operative for establishing a positive driving connection between said rotor and said rings in all positions of said rings on said rotor, whereby the rings will in all positions rotate with the rotor.

2. Ina rotary continuous casting machine, as claimed in claim 1, said rim having opposite radially disposed annular. side faces, each ring having a surface adjacent a face of said rim and being displaceable with said surface sliding along said face, the play between each respective face and surface being sufficiently large to permit easy displacement sliding movement of the ring and sulficiently small to restrain the entry therebetween of molten metal from the casting mold.

3. In a rotary continuous casting machine, as claimed in claim 1, said connecting means comprising involute gear means, said gear means allowing radial play of the rings relative to the rotor.

4. In a rotary continuous casting machine, as claimed in claim 1, said connecting means comprising involute gear means including a plurality of involute gear teeth and corresponding gear recesses cooperating between the rotor and each ring spaced apart from each other angularly substantially regularly throughout the periphery, said resilient means including a plurality of springs, a spring being positioned between each pair of gear teeth with their recesses.

5. In a rotary continuous casting machine, as claimed in claim 4, three gear teeth and their recesses being arranged and three springs.

6. In a rotary continuous casting machine, as claimed in claim 1, said connecting means comprising involute gear means between each ring and said rotor and including at least two gear teeth and two corresponding gear recesses cooperating between said rotor and each ring, said resilient means comprising at least two springs positioned intermediate said teeth, said rotor and each ring having radial depressions, the depression of each ring facing a depression of said rotor, and each spring being positioned between the facing depressions and acting radially thereby journalling said rings resiliently.

7. In a rotary continuous casting machine, as claimed in claim 1, and setting means operable for selectively variably setting said ring into a position of predetermined eccentricity relative to said rotor.

8. In a rotary continuous casting machine, as claimed in claim 7, said setting means comprising a pair of rolls adjustably positionable and being in rolling pressure contact with said outer edge portions of said rings at a point spaced from the entrance opening of said continuous casting mold at a location of said rotor and rings before they reach said entrance point during their rotation.

9. In a rotary continuous casting machine, as claimed in claim 7, said setting means comprising two pairs of take-up rolls, the first pair being positioned near said entrance opening, the other pair being positioned about mid- Way between said entrance and exit openings, the latter pair being adjustably positionable.

10. A mold Wheel for a rotary continuous casting machine having a cover band, said mold Wheel having a rim portion, a groove recessed in the rim portion extending around the circumference of the wheel and having a depth which changes progressively around the circumference of the wheel, the groove having a floor and side walls, the side walls being resiliently movable, relative to the floor, during rotation of the mold wheel to maintain contact between the casting, the floor and said cover band at any hypothetical point of the groove portion containing the casting, during rotation of the wheel.

References Cited UNITED STATES PATENTS 359,348 3/1887 Daniels 164-278 X 2,128,651 8/1938 Kohler 18-21 X 2,815,573 12/1957 Trelease 18--21 X 2,865,311 12/1958 Thiirlings 18-21 X 3,279,000 10/1966 Cofer l64-277 FOREIGN PATENTS 764,193 12/1956 Great Britain.

I. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner.

US. Cl. X.R. 164-280