US3171305A

US3171305A - Rolling mill

Info

Publication number: US3171305A
Application number: US107506A
Authority: US
Inventors: Morris D Stone
Original assignee: United Engineering and Foundry Co
Current assignee: United Engineering and Foundry Co
Priority date: 1961-05-03
Filing date: 1961-05-03
Publication date: 1965-03-02
Anticipated expiration: 1982-03-02
Also published as: GB952135A

Description

M. D. STONE March 2, 1965 ROLLING MILL 5 Sheets-Sheet 1 Filed May 3. 1961 INVENTUR. J/OPR/S 0. STONE BY @G- 1 ATTOR/Vf) March 2, 1965 a M. D. STONE 7 ROLLING MILL Filed May 3. 1961 5 Sheets-Sheet 2 INV EN TOR.

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Filed May 3. 1961 INVENTOR. Maze/s 0. b7'0/VE ATTORNEY Fig.4

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ROLLING MILL Filed May a. 1961 5 Sheets-Sheet 4 INV EN TOR.

MORE/.5 0. STONE Aime/var M. D. STONE ROLLING MILL March 2, 1965 Filed May 3. 1961 5 Sheets-Sheet 5 M6 M0 w m a $1.. L7 Arron/v57 United States Patent 3,171,305 ROLLING MILL Morris D. Stone, Pittsburgh, Pa., assignor to United Engineering and Foundry Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed May 3, 1961, Ser. No. 107,506 8 Claims. (Cl. 80-38) This invent-ion relates to an apparatus for processing metallic strip and, in particular, to a rolling mill having improved means for controlling the transverse thickness of the strip.

One mechanical way of correcting for transverse variations in strip gauge during the rolling process employing multi-high mills is to bend or flex one or more of the backing-up rolls in a direction to eliminate or reduce the inherent deflections of the working rolls caused by the holling loads. It will be appreciated that in this operation the net effect is to impose a crown on the working rolls, thereby to obtain a transverse uniform passhence, it is customary to refer to the operation as a crown control procedure. In the present day designs of multihigh rolling mills that have employed the aforesaid crown control procedure, it has been the practice to extend the necks of the backing-up rolls outward from their main bearings, and to which ends bending forces are imposed, thereby the moments thereof bend or flex these rolls. The bending forces of this dynamical condition must be taken by the main backing-up roll bearings and in turn by the screws of the mill. Accordingly, the employment of the crown control procedure necessitates substantially increasing the sizes of the bearings and mill screws over normal mill designs. An even more serious limitation, because of the enlargement of the size of the mill screws, is the requirement that the normal size of the mill housings be made substantially larger. Since these changes greatly increase the cost of the mill, they are obviously highly objectionable.

It is one of the objects of the present invention to provide means for resisting the bending forces of the roll bending moments, whereby to mitigate the effect of such forces when imposed upon the screws of the mill, and as a consequence, the screws and mill housings need not be increased in size.

It is another object of this invention to provide hydraulic means interposed between the housings and chocks of the backing-up rolls, and so arranged with respect to the mill screws that they will resist some or all of the bending forces imposed on the rolls, whereby such forces will not be imposed upon the mill screws.

It is another object of this invention to provide, at a location between the crown control roll bending means and the main bearings of the rolls, to which the roll bending means is associated, hydraulic means for exerting a force in opposition to the roll bending forces in a manner to resist such forces, whereby the main bearings and screws will be rendered free from the bending forces.

It is a further object of this invention to provide for associating the piston cylinder assemblies employed for bending the rolls with the piston cylinder assemblies for resisting the bending forces, whereby the last mention assemblies may be automatically operated in a manner to exert a presure which will be correlated to the bending forces.

It is a still further object of this invention to provide means for the quick and efiicient removal of the piston cylinder assemblies employed for bending the rolls from the rolls and for the quick removal of the roll to which such assemblies are normally operatively secured.

It is another object of this invention to provide for bending the backing-up rolls of a 4-High rolling mill or imposing a force tending to bend these rolls by arranging a pair of piston cylinder assemblies between the ends of the rolls, which assemblies are arranged to permit free removal of the working rolls, and are connected to the backing-up rolls in such a manner so as to assure that the bending forces will be imposed in a vertical plane passing through the axes of the rolls.

It is a further object of this invention to provide for connecting the roll bending cylinders to the ends of the rolls in such a manner that, notwithstanding the deflections of the rolls, the axes of the pistons and cylinders will be maintained substantially coincident.

These objects, as well as the other features and advantages of the present invention, will be better appreciated when the following description is read in light of the accompanying drawings of which:

FIG. 1 is a side view of a 4-I-ligh rolling mill incorporating the features of the present invention;

FIG. 2 is an end view of the operators side of the mill shown in FIG. 1;

FIG. 3 is an enlarged fragmental side view of the drive side of the mill shown in FIG. 1 having the working rolls removed and the hoist in position to effect removal of the roll bending cylinders.

FIG. 4 is an enlarged fragmental end view of the drive side of the mill that is shown in FIG. 3 having the working rolls removed and the hoists in position to efiect removal of the roll bending cylinders.

FIG. 5 is an enlarged end View, partly in section, of the bending moment resisting cylinder assemblies; taken on lines VV of FIG. 6;

FIG. 6 is a plane section view taken on lines VIVI of FIG. 5;

FIG. 7 is a view illustrating the hydraulic arrangement for the roll bending and moment resisting piston cylinder assemblies shown in the aforesaid drawings; and

FIG. 8 is a diagrammatical view of a modified form of the present invention.

With reference to FIGS. 1 and 2 there is illustrated a 4-High rolling mill comprising a pair of spaced apart housings 11 and 12 having

elongated windows

13 and 14 into which there is received chock-bearing assemblies 15 and 16 of a pair of

working rolls

17 and 18. In the mill shown, the working rolls are designed to be driven by spindles 19 which are connected to a drive, not shown.

Each of te working

rolls

17 and 18 are supported by backing-up

rolls

20 and 21 having main chock

roll hearing assemblies

22 and 23 mounted on the necks thereof and received

inthe windows

13 and 14. The various other components that go to make up the necessary operative parts of the rolling mill, including the screwdown assembly, will not be particularly referred to since they are not considered important in obtaining an understanding of the present invention. It is important, however, to make particular reference to the

screws

24 and 25 of the mill, which are vertically arranged in the upper portion of each housing 11 and 12, whereby their upper ends are drivenly associated with the screwdown gearing and their lower ends are engaged by the top horizontal surfaces of the top backing-up

roll chocks

22 and 23. This engaging relationship can be best seen in referring to FIGS. 2 and 5.

The crown control apparatus With reference again to FIG. 1, it will be noted that the necks of the backing-up

rolls

20 and 21 are extended outward from the housings 11 and 12, and on the end portions thereof there are secured bearing members 26. As shown in FIGS. 3 and 4 each bearing member consists of a combination radial roller-thrust bearing 27, received in a bearing chock 28, the chock having opposed horizontal projecting cars 29, which terminate into reduced cylindrical portions 31. It is a feature of this construction that the bearing chocks 28 be designed so that they are freely rotatable about the necks of the rolls, the significance of which will be explained hereinafter. The exact locations of the bearing members 26 relative to the center lines of the housings, of course, will be determined by the degree of crown control desired or allowable under the particular circumstances.

As shown in the first four figures of the drawings, connected to and extending between the reduced cylindrical portions 31 of the bearing members 26 are cooperative pairs of roll bending

piston cylinder assemblies

32 and 33 consisting of

pistons

32a, 33a and cylinders 32b and 33b. The cylinders of each pair are arranged in parallelism and spaced apart sufliciently to permit, particularly with respect to the operators side of the mill, the free removal of the working rolls, 17 and 18, with their chocks and 16, as illustrated best in FIG. 2. On the drive side, the spaced apart relationship of the cylinders afiord the necessary space to permit the spindles 19 to be drivenly connected to the working rolls.

As best shown in FIGS. 3 and 4 the outer ends of both the pistons and cylinders are provided with semi-circular recesses corresponding approximately to the diameters of the reduced cylindrical portions 31 of the bearing members 26, to which means they are secured by bearing caps 34 through the agency of a series of bolts 35. Retainer plates 36 are bolted to the ends of the cylindrical portions 31, and are extendable beyond the adjacent surfaces of the bearing caps 34, thereby to prevent the piston cylinder assemblies from working 01f the end portions of the bearing members 26. It is to be pointed out that the bolts 35 are made intentionally long in order to permit the caps34 to be loosened so that the piston cylinder assemblies can be slid off the ends of the bearing members 26, and yet avoiding the need for disconnecting the caps. The length of these bolts also plays a significant part in cooperating with the trolley hoist mechanism, yet to be explained.

It is important to observe that the piston cylinder assemblies 32 and 33 are so connected to the bearing members 26 that on actuation of the assemblies the pistons and cylinders of each assembly will always remain on the same center line, thereby avoiding any tendency of the piston and cylinder to cant relative to each other when the backing-up rolls and 21 are deflected. To accomplish this result, the cylindersand pistons (i.e. the pistons, when referring to the top backing-up roll 20 and the cylinders, when referring to the bottom backing-up roll 21), are permitted to rotate on the cylindrical portions 31 of the bearing chocks 28. In this connection, it will be noted in FIG. 3 that on the actuation of the piston cylinder assemblies both ends of the assemblies (i.e. the

pistons and cylinders) will move about radii drawn from points on the vertical center lines of the housings. In this case, since the cylinders and pistons are permitted to pivot on the deflection of the backing-up rolls, they will simply move vertically. about the aforesaid radii and since these radii are the same and the degree of the deflections of the two backing-up rolls are equal, the cylinders and pistons of each respective assembly will always remain on a common vertical center line.

As'mentioned heretofore, the bearing members 26 are freely rotatable about the necks of the backing-up rolls 20 and 21. To assistin explaining the aspects of this construction, reference is made tov FIG. 4, wherein there is illustrated the pair of roll bending cylinder assemblies 33 employed on 'the drive side of the mill, and where it will be observed that-the projecting cylindrical portions 31 of the bearing members 26 extend past the window 14 to a position in front of the housing 12. In the roll changing operation of the backing-up rolls 2t) and 21, for obvious reasons, it is desirable 'to remove the main

chock bearing assemblies

22 and 23 and the bearing members 26 as a unit. To obtain this result, the present invention provides for the bearing members 26 to be rotated degrees whereby the projecting ear portions 29 may be brought within the

windows

13 and 14, thus to take the dotted line position illustrated in FIG. 4. As illustrated, in this position the members 26 will pass readily through the

windows

13 and 14, and wherein their adjacent ends are secured together by a channel bar 37 which prevents their rotationduring the roll changing operation.

Another important feature of the freely rotatable bearing member construction is that it provides an arrangement whereby the roll bending forces will always be imposed on the backing-up rolls on the center line thereof and there will be no tendency, should there by any differential movement of the pistons, to create eccentric forces.

Apparatus for removing the roll bending piston cylinder assemblies toward and away from the rolls As shown in FIGS. 1, 3 and 4 it is a feature of this invention to provide a device for quickly and efilciently removing the

piston cylinder assemblies

32 and 33 from their connections with the bearing members 26. For sake of clarity, this device has only been shown on the drive side of the mill.

With reference to FIGS. 3 and 4 there is shown secured to the top of the housing 12 brackets 38 which extend away from the housing and terminate at a point directly above the upper bearing member 26. Aflixed to the brackets and extending in a horizontal direction is a large Lbeam 39 having flanged portions 41 which serve as tracks. The beam, as shown in FIG. 4, extends beyond the outer vertical faces of the housing 12 and at its ends there are mounted stop members 42. The length of the beam is of'course determined by the distance necessary to assure that the piston cylinder assemblies when retracted will clear the ends of the projecting ear portions 29 and allow the bearing members 26 to be rotated 90 degrees.

. To the beam 39 there is secured, for each piston cylin' der assembly, a manually operated trolley hoist 43. In view of the fact that these machines are well known com mercial units their details and operational functions are deemed to require no description. It may be well,- how ever, to state that the continuous chains 44, illustrated in part on FIG- 4, will be employed by a workman standing on the floor to operate the hoists and by which means he also will pull the hoists, including the piston cylinder assemblies, away from the rolls. Before the bolts 35 are loosened to free the caps 34, as previously explained, and before the retainers 36 are removed, the hoists are caused to support the weights of the cylinders 33b by means of cables which are shown in FIGS. 3 and 4. When this is done, it will be apparent that the weights of the pistons 33:: will still be carried by the top bearing member 26 In order to remove the weights of the pistons from the top bearing member 26, thereby to facilitate easy removal of the former from the latter, the pistons, after the fluid is permitted to be bled off from the cylinders, are allowed to lower themselves into the cylinders 33b. This is brought about by loosening the bolts 35 which are made long enough to permit the lower ends of the pistons to bottom in the cylinders, but yet still permit the caps 34 to be connected to'the pistons. Once this is performed the hoists may be pulled to the one side of the mill where they will come to rest against the stops 42. After this, the backing-up rolls can be removed as above explained. When the new backing-up rolls have been inserted into the mill, the piston cylinder assemblies may be brought back into their operative positions and quickly re-connected to the bearing members 26.

Pressure resisting means for the bending forces of the roll bending means As previously mentioned, the bending of the backing-up rolls to eifect crown controlling of the working rolls. necessitates, in present day mill design, an alteration of the mills to the extent of providing for large mill screws in order to withstand the bending forces set up in flexing the backing-up rolls. The present invention provides for resisting the bending forces in such a manner that the size of the mill screws will not be affected and, consequently, the size of the housings need not be increased.

This object is accomplished by providing in the preferred form means capable of creating a force equal to and exertable in a direction opposite from the bending forces of the bending moments at the point where the bending forces would normally be transmitted to the mill screws. With reference to FIGS. 5 and 6 there is shown an enlarged view of the operators side of the mill including the upper backing-up roll 20, its main chock bearing assembly 22, the mill screw 24 and the resisting means for the bending forces of the bending moments. It will of course be appreciated that a similar construction is provided for the mill screw on the drive side of the mill.

As shown in FIG. 5 the top surface of the chock 22 is relieved along its opposite sides for the entire distance of the chock, which construction presents two horizontal spaced apart surfaces 40 running parallel to a vertical plane passing through the axis of the screw 24. The surfaces serve to support the reaction or resisting

piston cylinder assemblies

45 and 46, each assembly being made of an integral forging provided with three cylinder bores 47, into which are received pistons 48. The cylinder assemblies are secured to the vertical walls of the chock by bolts 51 which are shown only in FIG. 6 and to the horizontal surfaces of the chock by another series of bolts 52, shown both in FIGS. 5 and 6. The chock is provided with outward extending lugs 53, the top surfaces of which are in line with the cylinder supporting surfaces of the chock and serve as continuation of these supporting surfaces in order to support the lower end portions of the

outer cylinders

45 and 46.

At the top of the window directly below the pistons 43, the housing 11 is relieved and provided with hardened steel discs 49 against which the pistons 48 of the cylinders engage.

Before the operation of the resisting piston cylinder arrangement is further explained, a description of the hydraulic system will be given.

Hydraulic system With reference to FIG. 7 there is illustrated the preferred hydraulic arrangement for the crown control procedure herein disclosed. As previously stated, it is one of the features of this invention to provide pressure means that will furnish a pressure equal to and exertable in a direction opposite from the bending forces that are imposed on the top backing-up roll 29 and which pressure will automatically adjust itself to the bending forces on the experience of a change in the latter. In the arrangement shown in FIG. 7, it will first be appreciated that the strokes of the roll bending

piston cylinder assemblies

32 and 33 and the reaction or resisting

cylinder assemblies

45 and 46 are equal. Moreover, the aggregate areas of the two groups of cylinders are also equal, i.e., the areas of the one pair of

piston cylinder assemblies

32 and 33 equal the areas of one set of the six

piston cylinder assemblies

45 and 46. In the illustrated hydraulic arrangement the cylinder assemblies are connected to a common hydraulic supply system, the result being that the pressure of the six cooperative reaction or resisting

piston cylinder assemblies

45 and 46 will always be equal to the roll bending pressure of the cooperative bending

piston cylinder assemblies

32 and 33.

This result is assured by connecting the roll bending

piston cylinder assemblies

32 and 33 by piping 54 to a main supply line 55, to which also the reaction

piston cylinder assemblies

45 and 46 are connected by piping 56. An operating valve 57 is provided in the main line 55, interposed between a pumping station and the piston cylin- 6 der assemblies. The valve 57 has the usual fluid dis= charge port which communicates with the pumpingstation 58 through piping 60. The necessary control relief valves 59 and 61 are installed in the hydraulic system, through which means a wide range of controllable pressures are made available.

In the operation of the roll bending apparatus, the operator will adjust the relief valves 59 and 61 so that on the opening of the valve 57 the pressure admitted to the roll bending piston cylinder assemblies will yield the desired crown. As explained above, the aggregate pressures of the reaction or resisting

piston cylinder assemblies

45 and 46 will equal the aggregate pressures of the roll bending

piston cylinder assemblies

32 and 33. As the desired degree of bending of the back-up rolls takes place, the pistons 48 of the resisting piston cylinder assemblies will exert their pressures against the top of the housings 11 and 12 and in turn against the top chocks 22, in a direction opposite to the bending forces of the bending moments imposed on the top backing-up roll 20 thereby to relieve the mill screws 24 and 25 of the bending forces.

Second embodiment With reference to FIG. 8 there is shown a second embodiment of the present invention. This embodiment has the advantage in that it will not only relieve the mill screws of the bending forces of the bending moments incident to the crown control procedure, but will also relieve the main backing-up roll bearings of such forces. As diagrammically shown in FIG. 8, there is provided a pair of working rolls 65 having chocks 66, the working roll being supported in the usual manner by backing-up rolls 67, the chocks 68 of which along with the working roll chocks 66 being mounted on the necks thereof and received in mill housing 69. The top backing-up roll chuck 68 is engaged by a mill screw 71 which extends vertically from the housing; Each backing-up roll has extended neck portions 72 on which is mounted a pair of spaced apart bearings 75 to which there is secured individual piston cylinder assemblies 73 and 74. The manner of connection between the bearing and piston rods of the asemblies may be similar to what has been illustrated in the first embodiment of the invention. As shown, the upper cylinder assemblies are connected rigidly to extensions '76 of the housing 69, whereas the lower ones are supported by the foundation. In this arrangement the innermost cylinder assemblies 73 are designed to furnish resisting forces equal to and in the direction opposite from the bending forces of the bending moments which are created by the roll bending cylinder assemblies 74. It is to be noted in this case that the beinding on the backing-up rolls by applying opposite directional forces creates a couple external of the main backing-up roll bearings 68. Hence, the main backing-up roll bearings 68 will only be exposed to the rolling load and not to the bending forces.

In accordance With the provisions of the patent statutes, I have explained the principles and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof. However, I desire to have it understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. Ina rolling mill for processing material in strip forrn comprising:

a housing;

at least one pair of rolls arranged in said housing having necks at their opposite ends;

chocks arranged in said housing mounted on the necks of each of said rolls;

a pair of screws arranged in said housing engageable with the chocks of one of said rolls for adjusting said roll toward and away from the material being processed;

means for imposing first forces in one direction on 7 each neck of said adjustable roll thereby to deflect said roll in a plane containing the axes of said rolls and wherein said screws are subject .to at least a portion of said first forces; and means for imposing second forces on each neck of said adjustable roll in a direction opposite to that in which said first forces are applied and at locations spaced from the application of said first forces to olfset the influence of said first forces on said pair of screws- 2. In an apparatus according to claim 1 in which said roll positioning means comprises a pair of screws, and said means for resisting the bending forces comprising first piston-cylinder assemblies for each screw engageable with said housing and chocksand arranged adjacent to said screws. 3. In an apparatus according to claim 2 in which said first piston-cylinder assemblies comprise:

more than one piston-cylinder unit and wherein at least one of said units is arranged on each of the opposite sides of said screws. 4. In an apparatus according to claim 2 in which said means for imposing bending forces on said roll comprise:

second piston-cylinder assemblies secured to the opposite ends of the rolls, the aggregate areas of the secondpiston-cylinder assemblies and the aggregate areas of the first cylinder assemblies forresisting the bending forces being equal; a fluid supply source; means for connecting said first piston-cylinder assemblies for resisting the bending forces and the second piston-cylinder assemblies for imposing the bending forces to said fluid supply source whereby the aggregate pressures exertable by said first and second assemblies will be equal, and means for regulating the pressure in said fluid supply source. 5. A rolling mill comprising: a pair of housings; windows in said housings; a pair of working rolls mounted in said windows; backing-up rolls mounted in said windows for supporting said working 'rolls and having their axes substantially in a plane containing the axes of the working rolls; main bearing-chock assemblies for said rolls; 7 outboard bearing chocks secured to the ends of said backing-up rolls at points outward of their main bearing-chock assemblies;

said outboard bearing chocks having opposed projecting portions extendable outward of two opposite ends of the chocks of said working rolls;

a pair of parallel spaced apart piston-cylinder assemblies at each of the ends of the backing-up rolls and extendable between the backing-up rolls and connected to said projecting portions of asid outboard bearing chocks to bend the backing-up rolls to effect crown control of the working rolls,

said piston-cylinder assemblies at each end of said backing-up rolls forming openings through which said working rolls pass during their removal from and insertion into the mill.

6. A rolling mill according to claim 5; wherein said piston and cylinder of each of said piston-cylinder assemblies are trunnion mounted on said projecting portions of said outboard bearing chocks whereby on operation of said piston-cylinder assemblies to bend the backing-up rolls the axes of the pistons and cylinders of each assembly will be maintained coincident.

7. A rolling mill according to claim 5; having hoist means mounted on said housing for engaging and supporting the weight of said piston-cylinder assemblies and for moving them laterally to and from the ends of the backing-up rolls.

8. A rolling mill, according to claim 5, wherein said outboard bearing chocks are rotatably mounted on said backing-up rolls so that they can be rotated to a first position where their ends will extend beyond said windows to a point in front of said housings, and to a second position where their ends will clear the said housings so that they can be removed with the backing-up rolls through said windows.

References Cited in the file of this patent UNITED STATES PATENTS 1,934,233 Malkin Nov. 7, 1933 2,039,959 'Iversen May 5, 1936 2,430,410 Pauls Nov. 4, 1947 2,611,150 Goulding Sept. 23, 1952 2,850,952 Horrib'ostel Sept. 9, 1958 2,897,538 Shapiro et al Aug. 4, 1959 FOREIGN PATENTS 1,233,402 France May 2, 1960 234,837 Germany Mar. 27, 1910 747,347 Great Britain Apr. 4, 1956

Claims

1. IN A ROLLING MILL FOR PROCESSING MATERIAL IN STRIP FORM COMPRISING: A HOUSING; AT LEAST ONE PAIR OF ROLLS ARRANGED IN SAID HOUSING HAVING NECKS AT THEIR OPPOSITE ENDS; CHOCKS ARRANGED IN SAID HOUSING MOUNTED ON THE NECKS OF EACH OF SAID ROLLS; A PAIR OF SCREWS ARRANGED IN SAID HOUSING ENGAGEABLE WITH THE CHOCKS OF ONE OF SAID ROLLS FOR ADJUSTING SAID ROLL TOWARD AND AWAY FROM THE MATERIAL BEING PROCESSED; MEANS FOR IMPOSING FIRST FORCES IN ONE DIRECTION ON EACH NECK OF SAID ADJUSTABLE ROLL THEREBY TO DEFLECT SAID ROLL IN A PLANE CONTAINING THE AXES OF SAID ROLLS AND WHEREIN SAID SCREWS ARE SUBJECT TO AT LEAST A PORTION OF SAID FIRST FORCES; AND MEANS FOR IMPOSING SECOND FORCES ON EACH NECK OF SAID ADJUSTABLE ROLL IN A DIRECTION OPPOSITE TO THAT IN WHICH SAID FIRST FORCES ARE APPLIED AND AT LOCATIONS SPACED FROM THE APPLICATION OF SAID FIRST FORCES TO OFFSET THE INFLUENCE OF SAID FIRST FORCES ON SAID PAIR OF SCREWS.