US3528487A

US3528487A - Continuous casting machine

Info

Publication number: US3528487A
Application number: US643562A
Authority: US
Inventors: James N Wognum; Emil Simich; Alvin L Winkler
Original assignee: Interlake Steel Corp
Current assignee: Acme Steel Co
Priority date: 1967-06-05
Filing date: 1967-06-05
Publication date: 1970-09-15
Anticipated expiration: 1987-09-15
Also published as: CH498674A; GB1222988A; DE1758454A1; NL6807794A; BE716065A; LU56195A1; DE1758454B2; AT287944B

Description

Sept. 15, 1970 wo uM ET AL 3,528,487

CONTINUOUS CASTING MACHINE Filed June 5. 1967 '7 Sheets-Sheet 1' p 15, 1970 J. N. WOGNUM ETAL 3,528,487

' CONTINUOUS CASTING MACHINE 7 Sheets-Sheet 2 Filed June 5. 19.67

In 1/ e7z/Z0ns' mes/VT Wqgnum P 15, 1970 J. N. WOGNUM El'AL 3,528,487

J. N. WOGNUM ETAL 3,528,487

CONTINUOUS CASTING MACHINE Sept. 15, 1970 Filed June 5. 1967 s Q 7 w J 0, a r w M M 3 w w W a rm m .59 m WM? m 7 m m l w E 3 W lv 1 w 1/ M a 5 if 0 a a 6 a w M L 4 w 5 N\\\\\\\\hi\\i\\\\\\\\\ y 1% w a I. I- l 3 0 a w w Sept. 15, 1970 J. N. WOGNUM ETAL 3,528,487

CONTINUOUS CASTING MACHINE '7 Sheets-Sheet 5 Filed June 5, 1967 yen Zora fines A! 'Waymmz/ affair? L. Wzmr EmiZ5z'mz'c2 (5/ lww PPMCMA Sept. 15, 1970 J. N. WOGNUM EI'AL CONTINUOUS CASTING MACHINE 7 Sheets-Sheet 6 Filed June 5, 1967 1 r IA Sept. 15, 1970 J. N. WOGNUM ETAL 3,528,487

CONTINUOUS CASTING MACHINE Filed June S 196? 7 Sheets-Sheet 7 ("H-F1 T I ,14 l I l I ll ,71.

uww QQ MI United States Patent ice 3,528,487 Patented Sept. 15,, 1970 3,528,487 CONTINUOUS CASTING MACHINE James N. Wognum, Emil Simich, and Alvin L. Winkler, Chicago, Ill., assignors to Interlake Steel Corporation, Chicago, 11]., a corporation of N ew York Filed June 5, 1967, Ser. No. 643,562 Int. Cl. B22d 11/00 US. Cl. 164280 8 Claims ABSTRACT OF THE DISCLOSURE Apparatus for continuous casting of metal having a cavity formed by a plurality of flexible mold sections which minimize the problems of mold warpage by thermal expansion. Resilient backup for the mold sections for controlling mold cavity contour, improved mold section operating means and arrangement therefor is also provided.

This invention relates to the art of continuous casting and particularly relates to improvements in continuous casting in a machine of the vibrating mold type as, for example, shown in U.S. Pat. No. 3,075,264 in the name of James N. Wognum.

The type of continuous casting machine is one having a cavity extending longitudinally through it, the cavity being open at its opposite ends and formed by the inside surfaces of a plurality of vibrating mold sections located around the cavity, one of the open ends of the cavity being the receiving end through which molten metal can be introduced into the cavity and the other end being for discharge of the metal after it is solidfied as a casting as it passes through the cavity. The mold sections may be vibrated in closed orbital paths to drive the casting being formed in the cavity through the cavity.

One of the problems associated with the operation of this type of continuous casting machine is created by thermal expansion of the [mold sections which creates an undesirable warping of the mold sections which, if permitted, can bind the machine and make it inoperative. Previously, solution of this problem has been sought by employing larger masses of metal for the mold sections to counteract the warpage by reliance on the strength of the extra metal. Experience shows that objectionable differentials in expansion of different parts of the mold sections due to the various temperature differentials is not arrested by the use of the added metal. Instead, applicant has discovered far more can be accomplished by the use of flexible and resilient mold sections of relatively small cross section and of minimal metal mass. By the use of flexible mold sections, applicant has found that the mold sections can be retained in their proper shape without warpage, even though thermal stresses are present. Therefore, it is the principal object of this invention to provide an improved continuous casting machine employing flexible mold sections of relatively small mass which, although subject to thermal stresses due to temperature differentials, can be easily retained in a proper configuration without objectionable warpage.

In order to accomplish the aforesaid object, it is another object of the invention to provide resilient backing means for each mold section which can be used to apply forces along the mold sections to keep them in their proper configuration when subject to the tendency for warpage due to the thermal stresses.

This can be accomplished by employing resilient means, such as springs, or by means of inflatable cushions, as another example, and in other ways.

One of the current problems with continuous casting machines, also involving thermal considerations, is that there is a tendency for the casting to shrink away from the internal side walls of the mold as the casting solidifies. The result is that the casting portions out of contact with the mold are difficult to cool properly. For this reason, even though coolant is circulated through openings in the mold itself, the lack of contact between the casting and the mold reduces the conduction of heat from the casting to the mold where the heat can be removed by the coolant. In fact, this separation of the casting from the mold leaves an air or gas space which is a poor conductor of heat which acts more like a heat insulator. For this reason, it is common to employ water spray cooling on the portions of the casting exiting from the mold. Water spray cooling is in some instances objectionable because it does not permit the casting to be transported directly from the mold into a controlled atmosphere for purposes of retaining a bright finish on the surface of the casting. In order to overcome this problem, it is another object of this invention to provide a mold having flexible mold sections which can be insured of ,contacting the external wall surfaces of the casting so that efficient transfer of heat can be effected from the casting through the internal walls of the mold and to the coolant circulating through the mold without necessarily requiring additional external cooling, as by water spray cooling, for example.

Especially when casting high alloy metals, it is desirable to employ molds of long length in order to insure that sufficient wall portions of the casting freeze thick enough so that the casting skin does not break and allow hot metal from the core of the casting to pour out through it which is a dangerous condition and one which causes a poor surface condition. With high alloy metals, the freezing range of the metal is very wide and this is the reason why more mold time is desired. However, in other molds, as the casting cools, it shrinks away from the mold wall surface and the cooling by lack of contact with the mold sections becomes inefficient. In fact, it seems that the mold for cooling purposes, should be no longer than the length which remains in contact with the casting. Thereafter, since the mold is very ineffective for cooling by conduction, it is desirable to employ a Water spray directed onto the casting emerging from the mold section. But, this suggests shortening the mold when the high alloy materials indicates the opposite requirement that the mold should be longer. Due to the increased assurance of proper cooling in the mold for its entire length because of the improvements of this invention, it is another object of the invention to provide an improved mold which can be made in longer lengths to accommodate those situations requiring the longer lengths.

Another object of the invention is to provide flexible mold sections which are connected only at one end to the mold section support structure. This permits the mold sections to freely lengthen and shorten longitudinally as heating and cooling occur. This further minimizes the stresses due to temperature differentials causing thermal expansion and contraction.

In order to maintain high heat transfer through the mold sections along their lengths, efforts have been made to provide special contours for the mold walls according to the expected thermal shrinkage of the casting as it progresses through the mold. However, this has been relatively unsuccessful because different contours are required for each different metal used because the different metals expand or contract by different amounts when subject to the same temperature differentials. Further, if advancement speed of the castings through the mold varies, each different speed suggests that a different contour be required. It is an object of this invention to provide a flexible mold section so that the mold can be employed with many different metals of different physical thermal properties and be operated at many different speeds without requiring any special predetermined coutouring of the mold sections to overcome difliculties created by uneven thermal expansion and contract and which can be adjusted while operating to cause the mold sections to deflect into proper contours according to the actual shrinkage contours of the castings.

It is another object of the invention to provide an improved modular type of construction for a continuous casting machine involving a casting unit module having all of the basic casting components contained within it which lends itself to ready insertion or removal in a continuous casting system and which has its major moving parts housed in dust-proof enclosures.

It is another object of the invention to provide a modular continuous casting machine having an improved radical construction readily permitting basic components to be employed for changeover to cast different sizes of cross section of castings.

It is another object of the invention to provide a continuous casting machine which can be assembled and disassembled readily for easy access to all parts of it.

It is still another object of the invention to provide such a machine which has an improved driving arrangement for causing the mold sections to vibrate through their orbital paths, including suitable vernier adjustment means for fine adjustment of the spacing of the mold sections relative to each other.

It is another object of the invention to provide improved linkage mechanism in the driving means for the mold sections, which linkage provides the desirable vibratory paths for the mold sections.

It is also another object of the invention to provide a resilient takeup for any play existing between the operating shafts and the bearings supporting them so that the linkage mechanisms employed are without looseness, even though there are no precision fits at the bearing connections.

Because it is desirable to have the individual mold sections fluid cooled by passing the coolant through bores extending internally through the mold sections and to have the mold sections easily removable from the casting machine assembly, it is necessary to have quick disconnects between the fluid coolant inlets and outlets to the mold sections. It is an object of this invention to provide improved disconnects which either automatically connect or disconnect the fluid coolant outlets and inlets or which can be operatively connected or disconnected to the mold sections. The means for accomplishing this can be by use of a connecting tubular piston which abuts against the mold section by means of spring pressure to close the connection or by means of fluid pressure.

It is a further object of the invention to provide improved corner inserts mounted between adjacent mold sections for the purpose of minimizing leakage of liquid metal from the casting at the corners of the mold while the casting is propelled through the mold. These improved corner inserts are made flexible and provided with relatively flexible backings which may be further backed by resilient members urging the corner inserts into intimate contact against the mold sections and thereby seal the flow of liquid metal from between the interfaces adjacent mold sections and corner inserts to follow the changeable contours of the flexible mold sections.

It is another object of the invention to provide certain proximity devices behind each mold section for the purpose of indicating externally of the mold that the contacting mold surfaces are in complete contact with the casting surfaces. These proximity or sensing devices provide sig- 4 nals for detecting and indicating this information while the mold is in operation. This is important because it is necessary for accuracy that the mold sections be adjusted dynamically during the casting operations so that the mold sections are accurately relocated to the changing sizes of shrinking or expanding portions of the moving casting while the casting is being progressively cooled.

It is another object of this invention to provide a continuous casting machine of the type described which has adjustable means at both the upper and lower ends of each mold section to allow for radial adjustment of either of the mold sections as required. This allows the lower ends of the mold sections to be radially shifted relative to the upper ends of the mold sections in order to compensate for the shrinkage of the casting as it solidifies.

It is another object of the invention to provide retainer blocks for the mold sections which are relatively rigid and made of material with relatively low susceptibility to thermal warpage at the operating temperatures of the machine. This provides relatively rigid backup means for the mold sections even though the mold sections themselves are flexible. It is important that the backup means for the mold sections be rigid in order to provide dimensional stability to the apparatus.

Other objects and advantages of the invention should become apparent upon reference to the accompanying drawings in which:

FIG. 1 shows a preferred embodiment of continuous casting machine made according to the invention in the form of a modular unit;

FIG. la shows a cross-sectional view of a spring retaining means employed with the unit of FIG. 1;

FIG. 2 shows a horizontal cross section of the major functional parts of the mold portion of the preferred embodiment of the continuous casting machine shown in FIG. 1;

FIG. 3 shows a perspective view, primarily from the rear, of a mold section support and the mold section it supports;

FIG. 4 shows a perspective view, primarily of the front portion of the apparatus shown in FIG. 3;

FIG. 5 shows a perspective exploded, partially cutaway and partial sectional view of a mold section and its related components separate from its support indicated in FIGS. 3 and 4;

FIG. 5a shows a cutaway sectional view of an alternate construction of mold section to that shown in FIG. 5;

FIG. 5b shows a partially cutaway sectional and exploded perspective view of one form of resilient cushion employed as a backup for a mold section;

FIG. 50 shows a cutaway portion in section of an alternative form of resilient backup means for mold section.

FIG. 5a' shows a cutaway portion in section of still another alternative form of resilient backup means.

FIG. 52 shows a cutaway portion in section of still another alternative form of resilient backup means.

FIG. 6 shows a partially cutaway sectional and perspective view of a linkage box, including the linkages and drive shafts for vibrating a mold section;

FIG. 6a shows a sectional view along the line 6a-6a of FIG. 6;

FIG. 7 shows a partially exploded perspective cutaway and sectional view of a corner insert and mounting structure for it; and

FIG. 7a shows a partially cutaway and sectional view I of the lower portion of the apparatus shown in FIG. 7.

The preferred embodiment of the invention shown in FIG. 1 consists of an entire continuous casting machine 1 containing all of the basic components of the machine in a modular unit. The machine is provided with an upper rigid plate 2 and a lower rigid plate 3 which are spaced from each other and extend in planes parallel to each other. The upper plate is provided with four grooves 4 extending at right angles to each other and radially outward from the center line 5 of the casting machine. The lower plate 3 is also provided with four radially extending grooves 6 which extend directly opposite the grooves 4. These grooves 4 and 6 function as keyways for relatively long rectangular keys 7 (FIG. 6) which are also keyed into grooves 8 provided in the upper and

lower surfaces

9 and 10 respectively, of a linkage box 11. In the particular embodiment shown, there are four linkage boxes 11 because there are four mold sections operated. Of course, if fewer or more mold sections are employed, there will be required a linkage box 11 for each mold section to be vibrated.

These linkage boxes 11 are suitably positioned and located radially between the upper and lower plates 2 and 3 and then secured in place suitably by means of screws 12 extending through the plates 2 and 3 and the keys 7 and into the upper surfaces 9 of the linkage boxes 11.

Surrounding each linkage box 11 is a mold section support 13 which is driven by means of the linkage and shafts contained therein, as hereinafter more fully described. Each of the mold section supports 13 supports a mold section 14. Each mold section support 13, particularly shown in FIGS. 1, 3 and 4, consists of a longitudinal frame member 15 joined to two side plates 16.

The side plates are substantially triangularly shaped andprovided with a rear brace 17 bridging between them. The frame member .15, the side walls 16 and the rear brace 17 are suitably connected by welding or screws into an integral box-like shape. The upper regions of the side plates 16 are provided with round openings 18 and the lower portions are provided with other round openings 19. As hereinafter described, these

openings

18 and 19 provide journals for the ends of certain shafts which are driven through orbital paths to cause the mold section supports 13 to move through corresponding orbital paths.

In order for the machine to cast a casting having a substantially square cross section, the principal functional parts of the machine are arranged as shown in FIG. 2. Four mold sections 14 are alternately positioned with mold sections 14 in pairs facing each other so that the inside surfaces 14a of the four mold sections 14 face in- Wardly toward the center of a cavity formed by the mold sections 14 through which the casting 20 is propelled by the mold sections 14. As previously mentioned, each mold section 14 is supported by a frame member 15. Each of these frame members 15 is provided with a T-shaped groove 21 extending for its entire length. This groove 21 is bounded by two inwardly extending lips 22 having rear surfaces 23 against which edge flanges 24 of each mold section can abut as a limit on the movement of the mold section inwardly toward the center line of the mold cavity. A rear wall 25 of the frame member 15 provides the bottom surface of the T-shaped groove 21.

In the embodiment shown in FIG. 2, each mold section 14 is spaced from the rear wall 25 by means of an inflatable cushion or pillow in the form of a tube 26 which can be inflated to bear against the mold section 14 and urge it inwardly toward the center of the mold cavity. To act as a spacer shield and partial insulator between the mold section 14 and the inflatable cushion 26, a flat stainless steel strip 27a is positioned between the rear wall 14b and the front wall 26a of the cushion 26.

The purpose of the inflatable cushion 26 is to provide a continual pressure substantially uniformly along the entire length of a mold section 14 to counteract any tendency of the mold section .14 to objectionably bow or otherwise warp and to allow the mold section 14 to be displaced relative to its frame member 15 when the inside surfaces 14a of the mold sections are brought firmly into contact against the surface 20a of the casting 20.

In the copending application of James N. Wognum, Ser. No. 601,738, filed Dec. 14, 1966, there is disclosed the use of corner inserts for minimizing leakage at the corner regions between the mold sections 14. In the embodiment shown in FIG. 2, these corner inserts 27 are of 6 substantially square cross section and positioned between the side walls of adjacent mold sections 14 to bridge the corners 28 of the casting 20. Similarly, to maintain the corner inserts 27 in position, a T-shaped backing plate 29 is provided with its leading edge abutting against the insert 27. This backing plate has two shoulder surfaces 30 which are limited in their movement toward the center of the mold cavity by other shoulders 31 on a frame member 32 which are surfaces of a T-shaped groove 33 extending longitudinally along the frame member 32. Provided in the groove 33 is another inflatable cushion or tube 34 which, when inflated, bears against a flat retaining strip 35 which in turn presses against the rear surface of the backing plate 29 to urge the backing plate into contact with a corner insert 27 The corner inserts 27 are preferably made of small cross section, as indicated, and of a material such as graphite which has a smooth surface and is a good heat conductor.

One embodiment of the mounting construction for a mold section is shown in FIG. 5. The frame member 15 is also substantially T-shaped with flange portions 15a providing the means for securing the side walls 16 thereto. The central region of the frame member 15 is pro vided with a bore 36 through which coolant fluid is introduced for maintaining the temperature of the mold section 14 at its proper level. Secured to the rear lower face of the frame member 15 is a manifold 37 which carries suitable openings for the proper introduction of coolant and air under pressure. In the embodiment shown in FIG. 5, the manifold has an opening 38 leading to the bore 36, an opening 39 leading to the bore 40 and an opening '41 leading to the bore 42. There is also an opening 43 which leads to a bore 44 which is a conduit for two wires 45 leading to and from a proximity device 46, as hereinafter more fully described,

The same coolant that is introduced into the bore 36 returns after it has passed through the upper length of the frame member 15 and through openings 14c extending through the mold 14 until it reaches the bore 42 and passes out through the opening 41 in the manifold 37.

Air under pressure is introduced through the opening 39 into the bore 40 where it passes through the central bore 47 of a tube 48 around which the tubular stem 49 of the inflatable cushion 26 is positioned to allow the cushion 26 to be inflated. This provides the resilient backup for the mold section 14, as previously described upon reference to FIG. 2. A suitable packing plug 50 is provided in an enlarged portion 51 of the bore 40 in order to suitably retain the pin 48 and the tubular stem 49.

As indicated in FIG. 5, the inflatable cushion 26 extends for a substantial distance from adjacent the bottom of the frame member 15 to a location indicated at 52. Also, the mold section 14 is unrestrained in longitudinal sliding movement relative to the frame member 15 except at the upper end of the frame member 15 where suitable retaining means is provided from which the mold section 14 is hung. This retaining means consists of a retainer block 53 which is provided with a hollow bore 54 which connects with the bore 36 of the frame member 15 at an abutting region 55. The bore 54 has a front surface 56 which closely abuts the rear surface 14b of the mold section 14. A transverse rectangularly shaped key 57 extends in

suitable keyways

58 and 59 provided in the mold section 14 and the retainer block 53 respectively. In order to assemble the mold section into its proper location, the retainer block 53 is keyed to the mold section 14 and manually together they are lowered into place from the upper end of the frame member 15. After positioning, set screws 60 threaded through openings in the upper rear portion 15b of the frame member 15 are tightened against the rear wall 53a of the retainer block 53. In addition, an upper end cap 61 is positioned against the upper end of the retainer block 53 and upper end of the portion 15b of the frame member 15 and held in place by means of screws 62 as a further retaining means for the retainer block 53.

The bore 54 of the retainer block 53 is L-shaped to lead into the upper ends of the bores 140 of the mold section 14 so that there can be a complete circuit of flow of coolant through the frame member 15, the retainer block 53 and the mold section 14.

At all necessary junctures between the parts where there is fluid flow of coolant, suitable O-rings are provided to prevent leakage. For example, an O-ring 63 is provided at the upper end of the assembly between the bore 54 of the retainer block 53 and the bores 140 of the mold section 14.

With the arrangement shown, it should be apparent that the mold section 14 is truly hung from the upper end of the frame member 15 and it is free to expand and contract longitudinally as it is guided in the T-shaped opening 21 of the frame member 15. This lack of restraint, minimizes the tendency to bow or warp which is evident in mold constructions having fully restrained mold sections.

In order to maintain a leakproof seal at the lower end of the mold section 14 which is free to deflect radially of the machine, a plunger 64 is provided in the bore 42. The plunger 64 is provided with a helical spring 65 encircled about it which reacts against a Wall 66 of the frame member 15 and an annular flange 67 on the plunger 64. The spring 65 urges the plunger toward the opening 41 in the manifold 37. When the mold section 14 is properly positioned, air is supplied through the bore 40 to inflate the inflatable cushion 26. Simultaneously, the air is directed through another small bore 68 leading to an annular region 69 in the rear of the annular flange 67. The air pressure urges the plunger 64/ in a direction away from the opening 41 in the manifold 37 and toward the mold section 14. The end of the plunger 64 is provided with an O- ring 70 which is thereby urged into intimate contact around the openings leading to the bores 14c of the mold section 14 to thereby provide a fluid type connection. When it is necessary to remove a mold section 14 for replacement or repair, the air pressure is removed from the bore 40 which relieves the pressure in the inflatable cushion 26 and against the annular flange 67 of the plunger 64 so that the spring return relieves the pressure of the O-ring 70 from against the mold section 14. At that time, upon suitable loosening of the set screws 60 and the screws 62, the mold section 14 can be removed from the upper end of the assembly.

The proximity device 46 is one which provides a signal in the form of a change in D.C. voltage when there is a change in the presence of metal adjacent the front surface 46a of a detector 46b. A suitable proximity device is one which can be purchased from Bently Nevada Corp., Box 157, One Airport Road, Minden, Nev. The change in presence of metal is sensed by the detector 46b which is connected by the wires 45 to a detector driver 46c which has a D.C. voltage output which varies with the change in presence of metal at the detector. The variation in voltage output can be visually indicated on a meter 46d.

A proximity device 46 is provided in each mold section support 15 and there is a corresponding detector driver 46c and meter 46a for each proximity device 46. In operation, the mold sections 14 are placed in their orbital vibratory paths by means of their mold section supports 15 suitably driven through the drive systems mentioned by means of the motors 140. With no casting metal present, the inflatable tubes 26 keep the mold sections 14 pressed radially toward the center of the mold so that the edge flanges 24 of each mold section abut against the rear surfaces 23 of the inwardly extending lips 22 on the mold section supports 15. As casting begins, the metal casting travels through the mold cavity of the machine. The metal adjacent the top of the mold fills the cavity and presses against the inside surfaces 14a of the upper ends of the mold sections 14. However, ordinarily the casting shrinks as it progresses through the mold cavity so that there is a tendency for the mold portions of the inside surfaces 14a of the mold sections 14 to be out of contact with the casting at its lower end, To overcome this, the eccentric adjustments are made on the pins 130 to adjust the links 133 radially inwardly toward the center line 5 of the mold cavity until the inside surfaces 14a of the mold sections contact the casting. The indication that contact has been made by a mold section against the casting is when a cyclical pulsing of increasing and decreasing voltage appears on the meter 46d. This signifies that the mold section 14 is cyclically pressing against the casting as its edge flanges 24 reciprocate away from and toward the lips 22 of the mold section support 15. In order to make the proper adjustment, the eccentrics on the pins 130 are adjusted until the cyclical voltage variations on the meters 46d are pronounced and then the eccentric adjustments are made until the cyclical voltage variations are minimal. That point is reached when the edge flanges 24 of the mold sections 14 no longer reciprocate back and forth away from the lips 22 of the mold section supports 15.

The proximity device 77 indicated in FIG. 5a is of the same kind as proximity device 46 and it is suitably con nected by Wires to a detector driver and a meter similar to

items

460 and 46d for proper operation. Its adjustment is in an identical manner for the mold section 72 as for the mold section 14 when employing the proximity device 46.

As an alternate to the mold section support indicated in FIG. 5, there is another embodiment shown in FIG. 5a. There are basically the same components but their structures are somewhat different. There is a manifold 71 corresponding to the manifold 37, mold section 72 corresponding to the mold section 14, a frame member 73 corresponding to the mold section 14, a frame member 73 corresponding to frame member 15, an inflatable cushion 74 corresponding to inflatable cushion 26, a bore 75 through the frame member 73 corresponding to bore 36, a bore 76 corresponding to bore 40, a proximity device 77 corresponding to the same device 46 and a plunger 78 corresponding to plunger 64. There is also a spring 79 which acts reversely of the spring 65. Spring 79 urges the plunger 78 toward the mold section 72 rather than away from it, as does spring 65.

The lower end of the mold section 72 is provided with a sloped surface 80 which reacts against the leading sur face 81 of the plunger 78 which is urged against the mold section 72. The plunger surface 81 is likewise directed along the same angular inclination as the surface 80 and the plunger 78 is guided in a bore 82 which is similarly sloped and which carries the spring 79. With this construction, as the mold section 72 is lowered into position, its lower surface 80 cams against the surface 81 of the plum ger 78 and the plunger 78 remains in contact with the mold section 72 by the action of the spring 79, regardless of the relative position of the mold section 72 radially relative to the center of the mold. This system of maintaining of fluid-type connection at the lower end of the mold section 72 has the advantage that no air pressure is required. Instead, reliance on a spring is all that is necessary. v

Another significant difference is the manner in which the mold section 72 is suspended from the upper end of the assembly. The upper end of the mold section 72 is provided with a keyway 83 which engages with a shoulder 84 of a retainer block 85. The retainer block 85 has a sloped bottom surface 86 which mates with a correspondingly sloped surface 87 at the upper end of the frame member 72. For assembly purposes, the mold section 72 is assembled to the retainer block '85 by engaging the shoulder 84 with the keyways 83. In assembled form the mold section 72 is then lowered into a T-shaped slot corresponding to the slot 21 in the frame member 15. Another surface 86 bottoms on the surface 87 and further downward urging of the retainer block 85 causes tighter engagement of the shoulder 84 in the keyway 83. This provides an insured tightness. Then, with the retainer block 85 and the mold bar 72 in position, an end 88 is positioned above the retainer block 85 and secured in place by means of screws 89 extending through the cap 88 and the frame member 73.

Although the inflatable cushion 26 can be made of molded plastic or rubber in a single piece, the inflatable member 74 is shown to be of a different construction. As indicated in FIGS. a and 5b, it consists of a flattened tube 74a as a main body portion which can be made of thin wall brass tubing or other metal. The ends of the tube 74a are provided with plugs 74b which are preferably made of brass and silver soldered in place. Also soldered at the lowerend of the tube 74a is a sleeve 740 which is provided with a central bore 74d which leads to an opening 74e in the wall of the tube 74a so that air under pressure can be introduced into the tube 74a. Because of the limited travel required of the expanding walls of the tube 74a, this particular structure is quite suited for the purpose intended, especially because of its greater durability over the inflatable cushion 26 made of rubber or plastic. In addition, as a suitable shield for the inflatable cushion 74,

flat strips

90 and 91 of stainless steel are positioned along opposite surfaces of the tube 74a.

Another important feature of the mold section 72 is the use of transverse grooves 92 cut into the mold section 72. The purpose of these is to make the mold section 72 as flexible as possible so that minimum forces are re quired to keep the mold section 72 free of an undesirable warpage from thermal stresses and to allow the mold section to conform to the shrinkage contour of the surface of the casting.

With reference to FIGS. 7 and 7a, each of the corner inserts 27 is supported in a manner similar to each of the

mold sections

14 or 72, as previously described with reference to FIG. 2. Further, although inflatable cushion 34 shown in FIG. 2 can be made of rubber or plastic, it can also have a construction similar to that which is shown in FIG. 5b for the inflatable cushion 26.

As indicated in FIG. 7, the backing plate 29 or the corner insert 27 can be provided with transverse slots 93 which are intended to make the backing plate 29 more flexible. There is no equivalent of the backing plate 29 shown for the support of the

mold sections

14 or 72. These slots 93 extend to intersect circular bores 94 extending transversely through the backing plate 29 for the purpose of minimizing stress concentrations which can lead to cracking. The upper end of the assembly is provided with an end cap 95 which is held in place on the frame member 32 by means of two screws 96. This end cap 95 keeps the backing plate 29 securely positioned. This arrangement makes it very simple to replace corner inserts 27 which may become damaged or broken.

Keyed to two projecting

key portions

97 and 98 at the rear of the frame member 32 are two

brackets

98 and 99 which are provided with mounting

holes

100 and 101 which permit securement to the upper and lower plates 2 and 3 of the machine.

As indicated in FIG. 7a, there is shown the details of the lower portion of the assembly for holding corner insert 27. The bracket 99 is secured to the frame member 32 by means of two

screws

102 and 103 and a locating pin 104. The screw 102 and the locating pin 104 extend through another mounting bracket 105 which has a vertical wall 106 against which the frame member 32 rests. An upper Wall 107 of the mounting bracket 105 provides support for a cover plate 108 secured to the bottom end of the backing plate 29 and the backing plate 108 also supports the lower end of the corner insert 27. The screw 103 passes through a threaded hole 109 which is sloped downwardly so that the end of the screw 103 can react against a ,sloped surface 110 on the frame member 32 to thereby firmly retain the assembly by urging the frame member 32 snugly against the vertical wall 106 of the 10 mounting bracket 105. The inflatable cushion 26 is of the same general construction as the cushion 741: shown in FIG. 5b, as employed as a backing for the

mold sections

14 or 72. However, the other type made of rubber or plastic can also be employed. However, as shown in FIG. 7a, the lower end of the inflatable cushion 26 is provided with an inlet conduit 111 which is preferably silver soldered to the cushion 26 and which permits the inflating .of it with a source of pressurized air. In addition, the

backing plate 29 shown in FIG. 7a is provided with additional slots 112 which can be added along the front edge of the backing plate 29 to further increase the flexibility of the backing plate 29 to further minimize the forces required to resist undesirable Warpage or deformation due to thermal stresses.

As shown in FIG. 6 and partially in FIG. 1, the linkage box 11 has two side walls 11a which are joined with upper wall 9, the lower wall 10 and front and back walls 11b and to provide an entirely enclosed container for the linkages required to properly actuate the mold sections.

Within each linkage box 11 is a main driven link 113 which is journaled at its lower end 114 on an eccentric portion 115 of a shaft 116. The upper end of the link 113 is pivoted on a pin 117 to one end 118 of a link 119. The other end 120 of the link 119 is journaled on a shaft 121 whose outer ends on either side of the link are journaled in a fixed position in the side walls 11a of the linkage box 11. Adjacent to the upper end of the link 113 is another shaft 122 which extends through the side walls 11a of the linkage box 11 clear of any contact with the linkage box 11 and journaled into the openings 18 previously mentioned as provided in the side walls 16 of the mold section support 13. Suitable bushings or other bearings can be provided for increasing durability of these bearing connections.

Intermediate between the upper and lower ends of link 113 is another pin 123 extending through the link 113 with its ends journaled in one end 124 of a link 125 whose other end 126 is journaled on a pin 127 mounted at the upper end 128 of a link 129. The link 129 extends substantially parallel to the link 113 and has its lower end provided with a pin 130' whose ends are journaled in a fixed position in the side walls 11a of the linkage box 11. Slightly above the lower end of the link 129 another pin 131 is provided in the link 129 with its ends extending laterally therefrom and journaled to one end 132 of another link 133 whose other end 134 is provided with a shaft 135 extending laterally from both sides of the link 133 and through the side walls 11a of the linkage box 11 without any contact thereof and journaled in the holes 19 previously referred to in the side wall 16 of the mold section support 13. Suitable bushings or other bearing means can be provided in these regions for durability, similar to What are provided for shaft 122.

Two

spacers

136 and 137 are provided between the side walls 11a of the linkage box 11 and they are suitably secured in place by screws or other fastening means.

With the linkage arrangement disclosed, it should be apparent that rotation of the main shaft 116 causes its eccentric portion 115 to provide a vibratory orbital movement of the lower end 114 of the link 113. This orbital motion is imparted to both of the

shafts

122 and 135. Such motion is delivered to the shaft 122 directly through the link 113. Such motion is delivered to the shaft 135 through the link 125, the link 129 and the link 133. Suitable variations in the positions of the

shafts

122 and 135 relative to the linkage box 11 can be obtained by providing the

shafts

121 and 130 with adjustable eccentric bearing supports for the end portions of the

links

119 and 129 they support which

shafts

121 and 130 are adjustable by rotation. The purpose of these adjustments is to vary the location of the

shafts

122 and 135 relative to the linkage box 11 in order to vary the positioning of the

mold sections

14 or 72 as desired. By having varia tions on both

shafts

121 and 130, it is possible to vary the in and out positions of either the upper end or lower end of each mold section 14 without any significant change in the location of the other end not adjusted. In FIG. 6a, a suggested mounting for eccentric adjustment of the shaft is shown. The shaft 130 is provided with a central portion 130a which is eccentric of the center line 13% of the shaft 130. Two reduced portions 1300 and 130d of the shaft 130 are journaled directly in bearings 130a and the free end 130 extends beyond the portion 1300. A nut 130g is threadably secured on a threaded portion 13011 of the shaft 130 and ordinarily tightened against a shoulder 1301'. The eccentric portion 130a is mounted in a lower bearing 130i which journals it to the link 129. When it is desired to adjust the spacing of the shaft 130, the nut 130g is loosened and the shaft 130 is rotated by external access to the end 130f. The shaft 130 is rotated until the eccentric portion 130a rotates sufficiently to properly adjust the position of the bottom end of the link 129. This adjustment of the bottom end of the link 129 in turn adjusts the position of the link 133 and, in turn, that of the shaft 135. Similarly, the shaft 121 can be provided with an adjustment identical to that as shown for shaft 130 in FIG. 6a in order to adjust the position of the link 119 to, in turn, adjust the position of the shaft 122.

Another manner of acquiring some adjustment, not indicated, is to provide each

link

119, 125 and 133 with a turnbuckle centrally located on each one. Rotation of the turnbuckle can provide lengthening or shortening of the link desired. The advantage of the eccentric adjustment is that it can be arranged for external adjustment while the machine is operating.

The main shaft 116, as indicated in FIG. 1, is coupled at 138 to the drive shaft 139 of a driving motor 140. In the arrangement shown, there are four linkage boxes 11 because there are four mold sections shown as required to be driven and, likewise, there are four motors 140 for driving them. The motors are of a standard synchronous type so that the proper phase relationship of the motion of the mold sections can be maintained at all times during the operation of the device.

In order to maintain lateral stability of the mold sections, the mold section supports 13 are held in position by links 141 and 142. Link 141 extends between a side wall of the mold section support 13 and a bracket secured to the undersurface of the bracket plate 2. Link 142 connects between a side wall of the mold section 13 and a plate 143 which supports one of the motors 140. These links 141 and 142 are journaled at their ends to allow for the movement of the mold section supports 13 as they move through their orbital vibrations.

In order to provide a tight, rattle-free movement of each mold section support 13 without the use of precision bearing mounts, a takeup device 144 is provided on each rear brace 17 of each mold section support 13. Its components are particularly shown in FIG. la where each takeup device 144 has an outer cup-shaped shell 145 which is welded directly to a rear brace 17. Contained within a cavity 146 of the shell 145 is a plunger 147 which bears against the outer end of a coil spring 148 having an inner end which bears against the outer wall 110 of a linkage box 11. Secured by screws 149 to the outer wall 110 is a spring end positioning plate 150 provided with a circular opening 151 of slightly larger diameter than that of the spring 148 so that the end of the spring 148 can be contained in this opening 151. The outer end of the shell 145 is provided with a threaded opening 152 connected with an adjusting screw 153 which can be threadably adjusted along the opening 152 to provide for more or less compression of the spring 148 and thereby adjust the reaction forces of the spring 148 between the mold section support 13 and the linkage box 11. The purpose of this spring pressure is to bias all of the linkage shaft trunnion connections in one direction to remove any slack or looseness and thereby create a tight operating condition between the moving parts. This 12 maintains the desired tight condition even though the trunnion connections may not be precision fit and permits the use of standard bearings to minimize the cost of the installation.

Further, the fact that the linkages and mechanisms associated therewith are contained entirely within the linkage boxes 11 without any external exposure, there is excellent protection for these parts from dust or dirt in the area where the machine is to be used.

In the operation of the device, the synchronous motors 140 are operated to rotate the drive shafts 139 and cause the

mold sections

14 or 72 to vibrate through small orbital paths. Experience indicates that the bottom radial amplitude of vibration and the longitudinal amplitude of vibration relative to the longitudinal axis 5 of the mold can vary over a wide range with satisfactory results, and the operating frequency can also vary in a very wide range up to 50,000 cycles per minute and more. The amplitude selected are dependent upon the frequency chosen and the combination of amplitudes and frequency are selected on the basis of the desired surface condition sought on the casting and the speed of travel of the casting through the mold. Ordinarily, the opposite positioned mold sections 14 are vibrated approximately 180 degrees out of phase with the other two mold sections. In this manner, there are substantially always two mold sections approaching the casting 20 while the other two mold sections are moving away from the casting 20. This type of movement is fully described in U.S. Pat. 3,075,264.

The frame members 15 are preferably made of a metal having a very low coeflicient of thermal expansion at the operating temperatures of the machine which, in the vicinity of the frame members 15 is approximately 200 F. A very suitable metal is a low expansion alloy commonly known as Invar metal having an average coefiicient of thermal expansion between 0 F. and 200 F. of about 0.7 1O' which is very low as compared to other metals generally. Invar is an iron-nickel alloy having approximately 36% nickel. It is important that these frame members substantially retain their shape without significant warpage due to any thermal gradient in order to provide the rigid backup for the mold sections which are themselves flexible. It is important that the backup means be rigid and thereby provide dimensional stability to the apparatus. If the frame members 15 did excessively warp, due to a thermal gradient, the range of free movement provided for the flexible mold sections could be restricted too much so that binding of the casting in the mold could occur with resultant hampering of advancement of the casting through the machine.

As alternatives for the resilient backup means shown in FIGS. 2, 5, 5a, and 51), for the

mold sections

14 and 72, and the corner inserts 27, a construction indicated in FIGS. 5c, 5d or 52 can be employed. In FIG. 50, a mold section identical to mold section 72 is shown mounted on the frame member 161 similar to frame member 73, except it is machined to accommodate a plurality of coil type compression springs 162 retained in a plurality of recesses 163 extending in spaced relationship along the length of the frame member 161. These coil springs 162 react against the bottom ends 163a of the recesses 163 and a separator strip 164 which is positioned against the inner surfaces 160a of the mold section 160. There is a space 165 between the strip 164 and the frame member 73 to permit the required range of movement of the mold section 160 relative to the frame member 161 against the resilient pressure of the springs 162. With this arrangement, there is no requirement for fluid pressure as the resilient force against the mold section 160. In a similar manner, the corner inserts 27 can be adapted with suitable springs 162 instead of inflatable cushions or tubes 34.

As a further alternative construction, the parts as indicated in FIG. 5d can be employed. The construction is similar to that which is shown in FIG. 50, except that the recesses 166 shown are larger than the recesses 163 shown 13 in FIG. c. This is necessary to accommodate plungers 167 which substantially surround the springs 162. These plungers 167 react between the springs 162 and the separator plate 164, instead of having the springs bear directly on the separator plate 164. Otherwise the construction is the same.

In FIG. Se is still another construction which does not employ the use of springs. Instead, it is another form which employs fluid pressure introduced through a bore 168 which is substantially similar to bore 76 shown in FIG. 5a. However, the frame member 169 shown which supports the mold section 160 is provided with a passage 170 connected with the bore 168 to receive fluid under pressure from the bore 168. The passage 170 is connected by a plurality of smaller passages 171 to a plurality of cylindrical recesses 172 which contain pistons or plungers 173 guided for reciprocation therein. Each plunger 173 is provided with an annular fluid seal 174 to minimize or prevent leakage of fluid from the .passage 170 beyond the plungers 173 in the direction of the mold section 160. A retainer strip 164 is disposed between the plungers 173 and the mold section 160. It should be evident that the plungers 173 when provided with fluid under pressure from the passage 170 will cause them to bear with resilient pressure against the retainer strip 164 to, in turn, transmit the force to the mold section 160. This effect is quite similar to that achieved when employing the inflatable cushion or tube, previously described.

It should be evident that the structure shown in FIGS. 5c, 5d and 5e are all suitable constructions for providing resilient backup means for either the mold sections 160, or the like, or for the corner inserts 27, or the like.

Although the invention has been described as one relating to a particular type of vibratory casting machine, some of the principles can still be applied to other casting machines employing separate mold sections as opposed to the sleeve type mold. Further, although only a single embodiment and variations thereof of the invention have been shown and described, it should be clearly understood that the invention can be made in many diiferent ways without departing from the true scope of the invention as defined by the appended claims in which we claim:

1. Apparatus for continuous casting of metal of a type having a cavity extending longitudinally therethrough open at its ends and formed by the inside surfaces of a plurality of discrete mold sections unattached from each other located in a substantially closed periphery around the cavity with said inside surfaces disposed substantially parallel to the longitudinal axis of the cavity, one of said open ends of said cavity being a receiving end through which molten metal can be introduced into said cavty and the other of said open ends of said cavity being a discharge end through which said metal can be progressively discharged from said cavity, relatively rigid and inflexible frame members in which the mold sections are mounted, said mold sections having sufliciently small beam strength that they readily flex when stressed transversely as a beam as compared to the relatively inflexible and rigid frame members in which the mold sections are mounted.

2. Apparatus as defined by claim 1 characteribed by,

mold section mounting means for supporting said mold sections in their locations around the cavity, and resilient backup means applying a backup force reacting between the mounting means and the mold sections for overcoming the tendency of the mold sections to deform when subjected to the heat of the metal passing through the cavity during the casting period. 3. Apparatus as defined by claim 2 characterized by, said resilient backup means being in the form of an inflatable pillow which provides the backup force upon inflation of the pillow with fluid under pressure, and means for inflating the pillow with fluid under pressure.

4. Apparatus as defined by claim 2 characterized by, said resilient backup means being in the form of a thin walled metal tube which provides the backup force upon inflation of the tube with fluid under pressure, and means for inflating the tube with fluid under pressure.

5. In apparatus for continuous casting of metal of a type having a cavity extending longitudinally therethrough open at its ends and formed by the inside surfaces of a plurality of mold sections located around the cavity with said inside surfaces disposed substantially parallel to the longitudinal axis of the cavity, one of said open ends of said cavity being a receiving end through which molten metal can be introduced into said cavity and the other of said open ends of said cavity being a discharge end through which said metal can be progressively discharged from said cavity, relatively rigid and inflexible frame members in which the mold sections are mounted, said mold sections having sufliciently small beam strength that they are relatively flexible when stressed transversely as a beam, as compared to the relatively inflexible and rigid frame members in which the mold sections are mounted, and having a resilient backup means for applying a backup force to react against the mold sections for overcoming the tendency of the mold sections to deform when subjected to the heat of the metal passing through the cavity during the casting period comprising, said resilient backup means being in the form of-an inflatable tube which provides the backup force upon inflation of the tube with fluid under pressure, and means for inflating the tube with fluid under pressure, said tube being constructed of thin walled metal tubing having walls which readily flex and having fluid-tight end closures and inletoutlet means connected directly to the means for inflating the tube with fluid under pressure.

6. Apparatus as defined by claim 2 characterized by, said resilient backup means being in the form of a plurality of compression springs applying a backup force reacting between the mounting means and the mold sections for overcoming the tendency of the mold sections to deform when subjected to the heat of the metal passing through the cavity during the casting period.

7. Apparatus for continuous casting of metal of a type having a cavity extending longitudinally therethrough open at its ends and formed by the inside surfaces of a plurality of mold sections located around the cavity with said inside surfaces disposed substantially parallel to the longitudinal axis of the cavity, one of said open ends of said cavity being a receiving end through which molten metal can be introduced into said cavity and the other of said open ends of said cavity being a discharge end through which said metal can be progressively discharged from said cavity, said apparatus having an upper rigid plate and a lower rigid plate spaced from each other and extending substantially parallel to each other and in a direction transverse to the longitudinal axis of the cavity of the apparatus, each mold section having an independent mounting means for its support, each of said mounting means being mounted to extend radially with respect to the longitudinal axis of the cavity and between said plates to extend parallel to the longitudinal axis with the upper end of each mounting means secured to the upper plate and the lower end of the mounting means being secured to the lower plate, guide means on the plates for maintaining the mounting means in their radial positions, said mounting means being adjustable radially in the guide means so that the mold sections mounted on the mounting means can be adjustably positioned in movement radially of said longitudinal axis of the cavity.

8. Apparatus for continuous casting of metal of a type having a cavity extending longitudinally therethrough open at its ends and formed by the inside surfaces of a plurality of mold sections located around the cavity with said inside surfaces disposed substantially parallel to the longitudinal axis of the cavity, one of said open ends of said cavity being a receiving end through which molten metal can be introduced into said cavity and the other of said open ends of said cavity being a discharge end through which said metal can be progressively discharged from said cavity, mold section mounting means for sup- 15 16 porting each mold section independently in definite radial 3,321,008 5/ 1967 Jones l64--280 X positions relative to the longitudinal axis of the cavity, 3,388,737 6/1968 Buckwalter et al. 164283 each mold section mounting means being adjustable 3,364,980 1/ 1968 Loewenstein 164-281 radially so that the mold sections can be individually adjustably positioned to different positions radially of the 5 FOREIGN. PATENTS longitudinal axis of the cavity. 528,868 5/ 1954 g 65,298 1/1947 Denmark. References Cited UNITED STATES PATENTS I. SPENCER OVERI-IOLSER, Primary Examiner 2,195,809 4/1940 Betterton et a1. 16482 10 ANNEARAssistantExaminer 3,075,264 1/1963 Wognum 16483 3,237,252 3/1966 Ratcliife 164280 16443