US3709019A - Beam backed cluster mill - Google Patents

Abstract

A beam backed cluster mill, wherein deflections of the beams are substantially eliminated by (1) eliminating the horizontal components of the roll separating forces by the provision of multiple saddle blocks, wherein such horizontal components cancel each other, and (2) by prestressing the backing beams by means of moments which oppose the moments generated by the roll separating forces.

Description

PATENTEDJAN 9 I973 SHEET 1 BF 2 W R m M NN r WW S Y w my y m a n U um E v. D W0 m w mwi w 3. l Y

0 United States Patent 1 (111 3,709,019 Sendzimir [4 1 Jan. 9, 1973 54 BEAM BACKED CLUSTER MILL 3,529,462 9/1970 Tracy ..72/237 2 368 030 1/1945 Larsson ..72/242 [76] Inventor: Tadeusz Sendzrmir, PO. Box 1350,

W e bu y, Conn. 06,720 1,959,492 5/1934 Moses ..72/165 [22] Filed: Feb. 3, 1970 Primary Examiner-Milton S. Mehr Att Ml'l1,St ,F t &H ff PP 8,380 amey evi e rasser os er 0 man [57] ABSTRACT [52] US. Cl ..72/242, 72/21 A beam backed cluster mm wherein deflections of the Int. Clbeams are substantially eliminated eliminating [58] Field of Search ..72/242, 237, 21, 8, 241 the horizontal components of the to separating forces by the provision of multiple saddle blocks, [56] References cued wherein such horizontal components cancel each other, and prestressing the backing beams means of moments which oppose the moments 3,286,501 11/1966 Tracy ..72/237 generated by the roll separating forces. 3,147,648 9/1964 Sendzimir... .72/237 X 3,124,982 3/1964 Neumann ..72/21 7 Claims, 11 Drawing Figures PATENTED AN 9 i975 SHEET 2 BF 2 wvemon TADE'USZ SENDZIMIR BY LVILLE STRASSER v POWER 6 HOFFMAN AT TORNEYS BRIEF SUMMARY OF THE INVENTION The invention relates to rolling mill structures and particularly to such structures having incorporated therein cluster mills which may be such as are disclosed in Sendzimir US. Pat. No. 2,170,732, dated Aug. 22, 1939.

In such cluster mills, the roll separating force is taken up in oblique directions by the backing elements. These oblique forces have both vertical and horizontal components and conventionally the horizontal components are taken up by the backing beam of the housing which is rigid both in the direction of rolling and in a direction transverse thereto. The vertical components of course are also taken up by the backing beam. While the elastic deflections of the rigid housing beams are small, they nevertheless must be compensated for in order to produce a flat sheet; and the deflections caused by the horizontal components of the roll separating force add to those caused by the vertical components so that much greater compensation must be provided and thus the principal value and benefit of this type of mill, i.e., rigidity, is reduced.

According to the present invention, a mill is provided having housing beams which are subject to the vertical components of the roll separating forces only. The horizontal components or the majority thereof cancel each other. The structure herein described is particularly advantageous when more than one pair of backed work rolls are placed in tandem relationship for taking successive passes on the strip. Thus, a plurality of clusters may all be located in a single housing providing an extremely short center to center distance between working rolls.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side elevational view ofa pressure bearing element according to the invention.

- FIG. 2 is a fragmentary top plan view partly in horizontal section of a group of elements according to FIG. 1.

FIG. 3 is a fragmentary top plan view partly broken away to show the bottom beam of one embodiment of the invention.

FIG. 4 is a side elevational view of the mill shown in FIG. 3.

FIG. 5 is a view partly in front elevation and partly in vertical section of the mill of FIG. 4.

FIG. 6 is a horizontal cross sectional view through one of the columns.

FIG. 7 is a perspective view of a composite pressure bearing element wherein a plurality oflink saddles support one roll.

FIG. 8 is a side elevational view of another embodiment of the invention.

FIG. 9 is a fragmentary side elevational view of still another embodiment.

FIG. 10 is a fragmentary vertical sectional view showing a detail of the invention; and

FIG. 11 is a diagrammatic side view ofa detail of the invention.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention there is provided what is referred to herein as a link saddle, a plurality of which may be placed along the length of each work roll 1. Two backing shafts for the work roll are supported by the link saddles and there is one backing bearing between each two saddles. By an examination of the arrows in FIG. 1, it will be seen that the roll separating force 11 is resolved into the oblique forces 12 and 13 against the backing bearings 2. The oblique thrust on the backing bearings is resolved into vertical and horizontal components. In FIG. 1, it will be clear that the horizontal components 12' and 13 cancel each other so that only the vertical components are transmitted to the link saddle base 5. It may be mentioned that the only result of the opposite horizontal components l2 and 13' is to produce tension in the web of the link saddle 3 and this of course produces a slight amount of stretch. However, the amount of stretch is equal for all the saddles across the strip and need there fore not be compensated.

One embodiment of the invention is disclosed in FIGS. 3, 4 and 5 where there is shown a complete tandem strip mill having lower and upper housing beams 21 and 21', against which the several link saddles 3 bear. The mill housing proper consists of the lower beam 21, the upper beam 21 and four connecting columns 22. In each column 22 there is provided a tiebolt 23 and the tiebolts 23 are capable of providing a prestressing force which is considerably in excess of the roll separating forces which tend to push the beams 21 and 21 apart.

It will be observed that the tiebolts 23 do not pass through the center of the respective columns but are eccentric thereto in the direction of the centerline of the mill. By this arrangement, the pressure is greater toward the inside portions of the columns so that the interfaces between the columns and beams are not subjected to uniform I prestressing pressure. "The prestressing as described herein results in the beams 21 and 21' being very slightly bent so that the enters thereof are closer to each other. This is desirable since the roll separating forces tend to bend the beams in the opposite direction. Therefore, suitable proportioning and dimensioning of the columns, tiebolts and beams results in the faces of the beams, which carry the link saddles, being flat on their mutually opposed faces when subjected to roll separating forces.

Since the roll separating forces vary, it is preferred to use tiebolts 23 whose tension can be controlled. While this may of course be accomplished by means of hydraulic cylinders, one for each tiebolt and capable of exerting tension on it, a simpler way is shown in FIG. 6. Each tiebolt 23 may be provided with a central bore in which a controllable heating element 24 may be disposed. The tiebolt 23 is wrapped with a heat insulating layer 27. The temperature of each tiebolt may be determined in accordance with the prestressing force required as indicated by suitable deflection gauges measuring the deflection of the beams 21 and 21' both in the direction along the work rolls 1 and also in the direction of rolling. Such gauge for measuring deflections along a work roll may by example be placed inside a row of saddles 3 as shown in FIG. 1 by disposing a reference rod 14 with sufficient clearance in holes provided in the lower portions of the saddles 3. The rod 14 is anchored in the endmost saddles and carries a proximity probe 15 facing the central saddle 3 for measuring the vertical distance from it to the surface of the hole. This proximity probe may be of any type, as for example the KAMAN manufactured by Kaman Sciences Corporation of Colorado Springs, Col., which is a subsidiary of Kaman Nuclear Corporation. A signal from a proximity gauge 15 may, in a conventional manner, actuate an automatic temperature controlling system for the tiebolts 23.

For very wide mills, the above described control for assuring flatness of the mutually opposed beam faces across and along the strip may not be sufficient. In such cases similar tierods 17 may be disposed horizontally and transverse the rolling direction and engaging ledges 25 at the outside edges of the beams 21v and 21 so as to exert a bending moment upon each beam which is opposed .to the moment produced by the roll separating pressure. This structure is clearly shown in FIGS. 3, 4 and 5.

A row of saddles 3 is provided for each work roll 1 and the backing bearings 2 contacting the work roll along substantially its entire working face. The saddles may consist of individual piecesor an entire row of saddles can be fabricated as a single element as shown in FIG. 7. The saddles are secured to the faces of the housing beam 21 and 21 by suitable clamps and precision keys to insure parallelism.

Cluster mill arrangements as herein described, for example in connection with FIGS. 3 to 5 inclusive, permit of free shifting of the positions of the saddles in the rolling direction while maintaining their parallelism. It will be clear that when the axis ofa pair of work rolls do not lie in the same vertical plane, the pass line between them is not horizontal and causes the strip to follow a sinuous path. Such a sinuous path is desirable in many rolling operations since the rolls then tend to produce a flatter strip-Furthermore, when rolling very thin and wide strip, opposite rolls aid in preventing formation of longitudinal wrinkles. The shifting of the saddles may be accomplished as shown in FIG. 11. The normal position of the link saddle is shown in broken lines and the offset position in solid lines. In the normal position, base 5 of the-saddle 3 contacts a clamp 42. In the opposite position, a spacer 41 is inserted between the base 5 and the clamp 42. The horizontal dimension of the spacer 41 determines the amount of offset. In FIG. 11 the work roll la is shown in the position it occupies when offset from its normal position 1 and the upper work roll is simply lowered by the regular mill screwdown into appropriate pass position, thereby producing deflection of the strip.

The pyramid of rolls necessary for rolling hard metals which require very small diameter work rolls, can also benefit ifrom the present invention. Such an arrangement is shown in FIG. 8 wherein each work roll 1 is backed by a pair of first intermediate rolls 1. These in turn are backed by a cluster of three second intermediate rolls 1 of which the two outer ones are preferably driven. The three rolls 1" are in turn backed by four rows of spaced bearings 2 located in the saddles 3 which rest directly on the inner faces of the, beams 21 and 2l' or, as in the case of the saddles 7 and 7', they rest on spacers 28 which are keyed and secured to the inner surfaces of the beams. It will be clear that the horizontal components of the forces borne by the saddles 7 mutually cancel each other between two neighboring clusters, the endmost saddles 7 must have other means to take up the horizontal thrust. This is done by providing the sills 8 bolted to the housing beams 21 and 21' by bolts 26 and suitably keyed for parallelism.

It is the mutual cancellation of the horizontal pressure between the clusters which is responsible for the compactness of this type of mill and the maximum proximity of centers of adjacent mill clusters, regardless of the type and arrangement of backing elements. The mounting of the sills 8 and the spacers 28 is rigid in relation to the beams 21 and 21 so that any excess of horizontal pressure exerted by the backing bearings of one stand with respect to those of the adjacent stand, create bending moments which can easily be borne by the sills and spacers and the small deflection which may be caused for suchexcess is uniform over the whole width of the strip.

The compactness of the 1-2-3-4 tandem mill of FIG. 8 is further improved by limiting the outline of the. columns to the outline of the sills 8. This insures sufficient stability for the mill structure.

FIG. 9 shows one end of a mill similar to FIG. 8 but having what might be termed an outboard cluster. Thus, the beams 21 and 21 are extended beyond the corner columns by extensions 31 and 31 at one or both ends of the mill. This arrangement is very useful particularly for rolling hard materials because the relatively large diameter working rolls 1 of the outboard clusters may be used primarily for calibrating and tensioning the strip in preparation for the first real reducing pass by the first 1-2-3-4 cluster, while the 1-2 stand at the other end of the mill will be used to produce even exit tension and thereby assist in the production of flatter strip.

It is worthy of notice that under roll separating pressure, the overhanging portions 31 and 31' of the beams 21 and 21' produce a bending moment on said beams which counteracts the bending moments produced by the clusters between the columns of the mill, thereby reducing the total deflection.

While the side window of the mills shown in FIGS. 4, 8 and 9 must be kept free, at least on the operators side, to permit removal of rolls and saddles, removable intercluster columns or other means may be provided to reduce still further the deflection of the beams 21 and 21.

FIG. 10 shows a fragmentary cross section of the mill in a plane where two neighboring clusters meet. Projec-. tions 32 and32 are provided symmetrically at the right and left side of the mill to receive tierod 33 similar in all respects to the stationary tierods 23 described above. The projections 32 and 32' however are provided with slots rather than holes to accommodate the tierods 33 to facilitate removal thereof after expansion by a hoist or other means. One independent reference rod 34 is provided for each tierod 33 to measure the actual deflection of the beams 21 and 21 to provide a signal to counteract automatically the deflection by causing the respective tierod 33 to exert the correct amount of tension. Thereby the need for a prestressed column at this spot is avoided.

It will be clear that numerous modifications may be made without departing from the spirit of the invention and, therefore, no limitation not specifically set forth in the claims is intended or should be implied.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A rolling mill structure comprising two parallel beams, vertically spaced to accommodate roll structures therebetween, through which a strip may pass symmetrically in a rolling operation, said beams being connected to each other by at least four columns, one at each corner, disposed outside the width of the strip to be rolled, said columns determining the spacing between said beams, and at least one tension means for each column, said tension means being normal to said beams and disposed eccentrically with respect to the respective columns toward the centerline of the mill structure, said tension means being capable of exerting prestressing forces considerably in excess of the roll separating forces to be encountered, and said eccentric disposition imposing bending moments on said columns and beams in opposition to those produced by the roll separating forces.

2. The structure of claim 1, wherein said tension means are controllable to vary the magnitude of the bending moments that produce in accordance with the actual roll separating forces encountered.

3. The structure of claim 1, wherein said beams are provided with ledges along their opposite outer edges in the rolling direction, and wherein a plurality of tie rods normal to the rolling direction engage the respective ledges so as to exert bending moments on said beams in opposition to those produced by the roll separating forces.

4. The structure of claim I, wherein at least one cluster mill is disposed in the space between said beams, said mill having spaced backing bearings, and link saddles for said backing bearings, said link saddles transmitting the vertical components of the roll separating forces to said beams, while absorbing the horizontal components thereof.

5. The structure of claim 4, having more than one cluster mill, wherein the horizontal thrusts exerted by the link saddles of one cluster are cancelled by opposite thrusts exerted by the link saddles of the adjacent cluster, while sills attached to said beams take up the horizontal thrusts of the endmost saddles.

6. The structure of claim 4, wherein said beams extend beyond said column, and an additional cluster is disposed in the extended portion of said beams, whereby the bending moments produced by the roll separating forces of said additional cluster counteract the bending moments produced by the roll separating forces on the clusters inside said columns.

7. A rolling mill according to claim 1, including means to detect a deflection of said beams, said tension means being adjustable, whereby any detected deflection of said beams may be eliminated by adjustment of said tension means.

Claims (7)

1. A rolling mill structure comprising two parallel beams, vertically spaced to accommodate roll structures therebetween, through which a strip may pass symmetrically in a rolling operation, said beams being connected to each other by at least four columns, one at each corner, disposed outside the width of the strip to be rolled, said columns determining the spacing between said beams, and at least one tension means for each column, said tension means being normal to said beams and disposed eccentrically with respect to the respective columns toward the centerline of the mill structure, said tension means being capable of exerting prestressing forces considerably in excess of the roll separating forces to be encountered, and said eccentric disposition imposing bending moments on said columns and beams in opposition to those produced by the roll separating forces.

2. The structure of claim 1, wherein said tension means are controllable to vary the magnitude of the bending moments that produce in accordance with the actual roll separating forces encountered.

3. The structure of claim 1, wherein said beams are provided with ledges along their opposite outer edges in the rolling direction, and wherein a plurality of tie rods normal to the rolling direction engage the respective ledges so as to exert bending moments on said beams in opposition to those produced by the roll separating forces.

4. The structure of claim 1, wherein at least one cluster mill is disposed in the space between said beams, said mill having spaced backing bearings, and link saddles for said backing bearings, said link saddles transmitting the vertical components of the roll separating forces to said beAms, while absorbing the horizontal components thereof.

5. The structure of claim 4, having more than one cluster mill, wherein the horizontal thrusts exerted by the link saddles of one cluster are cancelled by opposite thrusts exerted by the link saddles of the adjacent cluster, while sills attached to said beams take up the horizontal thrusts of the endmost saddles.

6. The structure of claim 4, wherein said beams extend beyond said column, and an additional cluster is disposed in the extended portion of said beams, whereby the bending moments produced by the roll separating forces of said additional cluster counteract the bending moments produced by the roll separating forces on the clusters inside said columns.

7. A rolling mill according to claim 1, including means to detect a deflection of said beams, said tension means being adjustable, whereby any detected deflection of said beams may be eliminated by adjustment of said tension means.

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