US3528273A - Rolling mill with roll-deflecting attachment - Google Patents

Description

p 1970 D. A. L. ELTON ET AL 3,528,273

ROLLING MILL WITH ROLL-DEFLECTING ATTACHMENT Filed June 27, 1966 5 Sheets-Sheet 1 Sept. 15, 1970 D. A. ELTON ET AL, 3,528,273

ROLLING MILL WITH ROLL-DEFLECTING ATTACHMENT Filed June 27, 1966 3 Sheets-Sheet 2 44 4-0 InvenlorS DEREK ARTHUR LAMBERT ELTON ROBERT JAHES'HARLOW JOHN AN DRE 'RA P 1970 D. A. ELTON ET AL. 3,528,273

ROLLING MILL WITH ROLL-DEFLECTING ATTACHMENT Filed June 27, 1966 5 Sheets-Sheet 5 Inventors DEREK ARTHUR LAMBERT ELTON ROBERT JAMES HRLOW JOHN ANDRE'TAC United States Patent Olfice 3,528,273 Patented Sept. 15, 1970 3,528,273 ROLLING MILL WITH ROLL-DEFLECTIN G ATTACHMENT Derek A. L. Elton, Poole, Dorset, Robert J. Harlow, Parkstone, Dorset, and John A. Tracy, Bournemouth, England, assignors to The Loewy Engineering Company Limited, Bournemouth, England, a corporation of Great Britain Filed June 27, 1966, Ser. No. 560,404 Claims priority, application Great Britain, July 12, 1965, 29,502/ 65 Int. Cl. B21b 13/14 US. Cl. 72-237 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a rolling mill having housing and chocks for supporting the rolls of the mill in said housings and includes a rolldeflecting attachment providing for at least one roll, said attachment comprises bearing support from said chocks and mounted on the end of said roll; pressure means acting on said bearings so as to apply couples of forces to said bearings and to deflect said roll for the purpose of varying the pass opening of the mill, said bearing having radial extensions to which the roll-deflecting forces are applied by said pressure means, and members extending longitudinally of said roll from one of said bearings to the other, said longitudinally-extending members being so arranged with respect to said bearings and to said pressure means as to be in pressure-transmitting contact with the radial extensions of said bearings.

This invention relates to rolling mills with roll-deflecting attachments, especially attachments of this kind which are provided for compensating deflections of the rolls of a rolling mill caused by the forces which act on these rolls during a rolling operation. These latter deflections cause changes in the shape of the pass openings between the working rolls of rolling mills, the openings becoming wider at their centres than at their ends, with the result that articles which are reduced in thickness by these openings vary in thickness across their width. These variations often exceed the prescribed tolerances, with the result that the rolled articles are unacceptable. This is most frequently the case with thin, flat articles, such as sheet or strip.

It has been attempted to remedy this deficiency by forming the rolls of a rolling mill with a camber or crown in their centre, which gives the rolls such a contour that the pass opening between the working rolls will, under no-load conditions, be of a shape which is the reverse of the shape produced by the rolling load. As the load of the mill rolls during rolling tends to widen the pass opening in the centre, the rolls are so contoured that they are thicker in the centre than at their ends. However, compensation of the deflection imposed on the rolls by their working load could only be achieved if this deflection was of the same magnitude as the roll crovm. This was a serious limitation.

In order to overcome this limitation, it has been pro posed to apply to the ends of the rolls of a rolling mill controllable forces which produced bending moments in the rolls which counteracted the bending moments produced by the rolling load. The crown of the rolls was In known rolling mills, the means for producing the crown-controlling bending moment generally included pressure units which acted on the ends of the rolls, so as to deflect them in the desired direction and to the desired extent, the pressure of the units being controllable in order to obtain bending moments of the required size. The pressure units acted on separate bearings arranged at. the ends of the rolls, the bearings being unsupported in the mill housings, so that the bearings of the roll ends encompassed by them could yield to the forces of the pressure units.

The pressure units were usually of the hydraulic type comprising a cylinder element and a piston element. The unit were either arranged between the corresponding ends of two rolls which together defined the roll-pass opening, or they were arranged between the bearings of one roll and rolling mill housings. The former arrangement had the disadvantage of obstructing access to the rolls and to the pass opening. Both arrangements also had the drawback of transmitting reactions to other parts of the rolling mill, in particular, to the main hearing chocks of the rolls and to their screwdowns. These reactions were often considerable and therefore added materially to the stresses to which the rolling mill components were subjected by the rolling load. Finally, the known arrangements were sometimes of complicated design and rather heavy.

It is an object of the invention to provide a roll-deflecting attachment which is free from these drawbacks.

The attachment according to the invention comprises bearings separate from the chocks of the roll to be deflected by the attachment, and mounted on the ends of that roll. The bearings may be outside those chocks or between them, the former arrangement being preferred. Pressure means are provided in the attachment which means apply couples of forces to the rolling question so as to deflect it for the purpose of varying the pass opening of the mill. The above-mentioned separate bearings have radial extensions to which forces are applied by the pressure means, thus producing couples of forces in those bearings which deflect them together with the roll ends.

An attachment according to the invention is provided with members extending longitudinally of the roll to be deflected and from one of the separate bearings of that roll to the other. These members are so arranged with respect to the separate bearings and to the pressure means of the attachment as to be in pressure-transmitting contact with the radial extensions of the bearings.

In this way, a roll-deflecting attachment is provided for rolling mills which is of simple and compact design. The attachment according to the invention can be fitted to a mill and removed from it without requiring dismantling and re-assembly of parts of the mill itself. The roll-deflecting forces produced through the attachment and which are often considerable are balanced within the attachment and therefore not transmitted to the mill itself. Thus, there is no need to strengthen part of the mill or to provide in the mill special means for taking these forces or their reactions. A roll-deflecting attachment according to the invention can therefore be used with existing mills without requiring substantial changes in the mill, if any.

Preferably, the pressure means provided in the rolldeflecting attachment according to the invention and acting on the bearings separate from the chocks of the roll to be deflected, are arranged between a bearing and the adjacent ends of the longitudinally-extending members.

The pressure means may be formed by at least one hydraulic unit having a cylinder element and a piston element, one of said elements being mounted on or attached to one of said bearings, and the other being mounted on or attached to the longitudinal members at their ends. The axis of the hydraulic unit is preferably parallel to the axis of the deflected roll.

Common pressure means may be provided in respect of both bearings of the deflected roll. In this case, the pressure means may be provided on one of these bearings, the roll-deflecting couple for the second bearing being transmitted thereto through the longitudinally-extending members from the pressure means. This results in a particularly simple arrangement, as one side of the rolling mill can be kept entirely free from any pressure means, and especially from any hydraulic units. It is also possible to divide the longitudinal members into two sections and to arrange the pressure means between the two sections. Alternatively, separate pressure means may be provided in respect of each of the two separate bearings of a deflected roll.

The longitudinally-extending members may consist of tie-rods, preferably arranged in pairs, the tie-rods of one pair being arranged parallel to and symmetrically with respect to the axis of the deflected roll, the ends of the tie-rods of a pair being connected to each other by crossbars.

During the operation of a roll-deflecting attachment according to the invention, axial forces are set up in the separate bearings and in the roll ends. These forces can be resisted by thrust bearings provided on the roll ends. However, this would increase the length of the deflected roll and add to the cost, particularly when the axial forces are considerable, as is frequently the case.

According to the invention, there are provided between the separate bearings of a deflected roll, one or more longitudinally-extending compression members which take the axial forces to which the separate bearings of the deflected roll are subjected by the roll-deflecting couples, said compression members being in engagement at both their ends with abutments formed on the separate bearmgs.

The compression members and the abutments may have curved contact surfaces so as to allow the bearings to rotate relative to the compression members when the bearings are subjected to the roll-deflecting forces.

Several embodiments of the invention will now be described in detail by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a side elevation of a rolling mill provided with a roll-deflecting attachment according to the invention.

FIG. 2 is a vertical section through the mill of FIG. 1 along the line II-II of FIG. 1.

FIG. 3 is a horizontal section through the mill of FIG. 1 along the line III-III of FIG. 1.

FIG. 4 is a partial end view of another embodiment of a roll-deflecting attachment according to the invention.

FIG. 5 is a partial end view of a still further embodiment of the roll-deflecting attachment according to the invention.

The rolling mill shown in FIGS. 1 to 3 has two laterally spaced-apart housings joined together at their tops by a crossbeam 12. The mill is of the four-high type and accordingly has two small-diameter working rolls 14 and 114 defining together a pass opening in which flat metal articles, such as sheets and strip, are reduced in thickness. Associated with each working roll is a large-diameter back- up roll 16, 116 respectively. The working rolls have at their ends necks 15, 115 respectively, and the back-up Iolls have necks 17, 117 respectively. The working rolls are driven through spindles 18, 118 respectively from a source of power, not shown.

The'housings 10 have windows 19 in which are provided bearing chocks 20 and 120 for supporting the necks 17 and 117 of the back-up rolls 16 and 116 respectively, as well as hearing chocks 22 and 122 for supporting the necks 15, 115 of the working rolls 14 and 114. Screwdown spindles 26 act on the chocks 20 of the upper backing roll 16 for adjusting the vertical positions of both the 4 i roll 16 and its associated working roll 14, whereby th distance of that latter roll from the other working roll 114, and thereby the pass-opening between the rolls 14 and 114 can be altered.

The design of a rolling mill so far described is wellknown.

In accordance with the present invention, the backing rolls 16 and 116 are provided with attachments for deflecting these rolls and their associated working rolls 14 and 114 in their common axial plane for the purpose of compensating deflections which these rolls undergo as a result of forces which act on them during a rolling operation.

In the following, an attachment according to the invention is described with reference to the upper back-up roll 16, but it is understood that a similar attachment is provided also for the lower roll 116.

The attachment shown in FIGS. 1 to 3 includes bearings 30 mounted on the overhanging ends of the necks 17 of roll 16, the bearings 30 being thus outside the bearing chocks 20 of that roll. The bearings 30 are not supported in the housings 10, but means may be provided for preventing their rotation about the axis of roll 16. They have housings 31.

It is to be understood that the roll-deflecting attachment may be provided in respect of the working roll 14 instead.

The housings 31 of the bearings 30 are fitted with bushes 32 in which the necks 17 are journalled, and are shown in FIG. 2 as being closed at their ends by caps 33 to protect the necks from dirt and scale. At their ends near the chocks 20, the housings 31 are provided with radial extensions in the shape of wings 34 projecting from the main part of the bearings 30 in an upward direction. A crossbar 36 is arranged next to each bearing 30 and outwardly of its wing 34. The two crossbars of the attachment are connected to each other by tension members consisting of two tie-rods 38 extending longitudinally of the roll 16 and parallel to its axis, the tie-rods being disposed symmetrically with respect to the vertical axial plane of roll 16 and secured to the crossbars by nuts 40.

Thus, the tie-rods and the crossbars form together a closed rectangular frame. Recesses 42 are provided in the chocks 20 "for the passage therethrough of the rods 38.

Pressure means are provided on one of the bearings 30 of roll 16, these pressure means consisting of a hydraulic unit 44 positioned between the wing 34 of the right-hand bearing housing 31 and the crossbar 36 arranged outwardly of the wing projection (FIG. 2). The hydraulic unit comprises a piston 46 and a cylinder 48, the former acting on the centre of the crossbar, while the latter is formed on the wing 34, but this arrangement may be reversed. Piston 46 may be secured to the crossbar 36 by any suitable means. The axis of the hydraulic unit 44 is above and parallel to the axis of roll 16.

In the embodiment of FIGS. 1 to 3, left-hand bearings 30 of roll 16 is not equipped with separate pressure means. Instead, a stud 50 is interposed between the wing 34 of the left-hand bearing 30 and the crossbar 36 arranged outwardly of that wing.

On admission of pressure fluid to the unit 44, two opposite forces are produced which act on the wing 34 and on the crossbar 36 respectively of the right-hand bearing. It will be readily seen from FIG. 2 that the force acting on that wing results in a couple which tends to turn the end of the roll 16 encompassed by that hearing in a counter-clockwise direction, thereby deflecting the hearing and the roll-end upwards. The force acting on the above crossbar 36 is transmitted through the tie-rods 38 to the other crossbar 36 and from there through the stud- 50 to the wing 34 of the left-hand bearing 30. This force produces in the left-hand bearing a couple tending to deflect that hearing and the end of the roll 16 encompassed by that hearing in a clockwise direction, thereby deflecting the bearing and the roll-end also upwards.

The pressure of the fluid admitted to the unit 44 is controllable, and thereby also the forces produced by that unit. Any known and suitable fluid pressure control means may be provided for that purpose.

If desired, each of the two bearings 30 of roll 16 may be provided with separate hydraulic units 44, in which case the stud 50 on the left-hand bearing is replaced by a hydraulic unit similar to that shown in FIG. 2 in respect of the right-hand bearing. In this case, force are produced by the two units which act in opposite directions on the wings 34 of both bearings 30, the reactions to these forces being taken by the tie-rods 38. The pressure of the fluid admitted to both units is controllable. As it is generally desirable that the deflections of both roll-ends are of the same magnitude, suitable means may be provided for equalising the pressure at both units. However, if, for any reason, unequal deflection of both roll-ends is required, for instance, in the case of the roll load being unevenly distributed over the roll, this can be taken into account by applying different pressures to each unit.

The couples acting on both bearings 30 set up axial forces in these bearings. These forces can be resisted by thrust bearings provided on the roll-ends. However, this would increase the length of the roll 16, and add to the cost, inasmuch as the axial forces can be considerable. According to the invention, there are therefore provided instead compression members which resist the above axial forces. These compression members are shown in FIGS. 1 and 2 as consisting of a pair of struts or beams 52 extending longitudinally of and parallel to the axis of roll 16, the two struts of a pair being arranged at opposite sides of the vertical axial plane of roll 16, and below the tie-rods 38. In the embodiment shown, the struts 52 are arranged substantially at the same level as the roll 16. The bearing housings 31 are provided at both sides with lugs 54 which contact the ends of the struts 52. A tight fit between the struts 52 and their lugs 54 may be obtained by providing the contact surfaces of the lugs of at least one bearing 30 on a separate piece and by making this piece adjustable in a direction towards the struts, for instance, by a wedge, not shown. In this way, attachment and detachment of the struts is also facilitated.

The ends of the struts 52 and the lugs 54 may have curved contact faces so as to enable the bearings 30 to follow freely the deflections imposed on them by the afore-mentioned couples.

The struts are shown in FIGS. 1 and 2 as being of rectangular cross-section and pass through recesses 56 in the chocks 20.

In the foregoing, a roll-deflecting attachment has been described with reference to the upper backing roll 16. A similar attachment is provided also in respect of the lower backing roll 116. The reference numbers used in the drawings for the roll-deflecting attachment of the lower backing roll are those used for the corresponding parts of the attachment for the upper backing roll, in-

creased by 100. The wings 134 of the bearings 130 of the roll 116 project downwardly from the housings 131, while the struts 152 are arranged above the tie-rod 138 substantially at the same level as the roll 116.

During the operation of a rolling mill as described, a flat imetal article enters the pass opening between the working rolls 14 and 114 after the latter have been adjusted by means of the screwdown spindles 26. As well known, the rolling operation produces a force in the mill which tends to separate from each other the two working rolls 14 and 114 and also the backing rolls 16 and 116. This force is strongest in the middle of the rolls, so that the pass opening during rolling becomes greater in its middle than at its ends; consequently, the rolled articles will be of non-uniform thickness across their width, which very often is a serious defect. The roll-deflecting attachment according to the invention is provided to remedy this. On the admission of pressure fluid to the units 44 and 144, the ends of the rolls 16 and 116 will be so deflected that the middles of these rolls tend to approach each other, with the result that the pass opening between the working rolls 14 and 114 is reduced in its size in its middle. By making controllable the pressure acting in the units 44 and 144, the roll deflection can be so adjusted that the deformation of the roll pass opening caused 'by the separating force is compensated and a pass opening of uniform size obtained. It will be understood that the deflections of the backing rolls 16 and '116 produced by the units 44 and 144 respectively are transmitted to the working rolls 14 and 114.

Both the working rolls and the backing rolls of a rolling mill to which the invention is applied may be formed with a camber or crown as is the practice in the type of mills to which the present invention refers. This camber can be of an order so as to offset to a certain extent roll deformation caused by the separating force, so that the roll-deflecting attachments provided in accordance with the invention have merely to compensate any remaining excess deformation of the rolls and the pass opening. This condition obtains when the camber or crown of the rolls is smaller than the maximum deformation of the rolls which is to be expected during the normal operation of the mill. As an alternative, the mill rolls may be formed with a camber which is equal to that maximum deformation. In this case, the roll-deflection provided by the attachments according to the invention is used for reducing the camber of the rolls. In order to achieve this mode of operation, the pressure units act on the roll bearings 30 in directions opposite to those occurring in the embodiment shown in FIGS. 1 to 3.

In the embodiment of FIG. 4, the struts 52 are replaced by blocks 60' arranged between lugs 54 and chocks 20. A spreader bar 62 is provided between the two chocks 20 so as to resist the forces imposed on the chocks by the blocks 60, the latter and the spreader bar being secured to the chocks by screws 64. There is then no need to provide recesses 56 in the chocks for the passage of the struts.

In the embodiment of FIG. 5, the struts 52 are replaced by a rod which passes through a central bore in the backing roll 16 and abuts with its ends against the caps 33 of the bearing housings 31. The rod 70 has therefore the same restraining effect on the axial displacement of the bearings 30 as the struts 52. The lugs 54 are then unnecessary.

It will be appreciated that the roll-deflecting attachment according to the invention is of simple and compact design and can be readily fitted to an existing mill. It does not obstruct access to the working rolls, as the attachment is arranged either above the upper backing roll or below the lower backing roll. Furthermore, any stresses set up by the attachment can be fully balanced within that attachment and not transmitted to other parts of the rolling mill.

The invention has been described in the foregoing in relation to a metal-rolling mill, but is equally applicable to rolling mills for plastic articles, such as sheets.

We claim:

1. In a rolling mill having a housing and chocks for supporting the rolls of the mill in said housings, a rolldeflecting attachment provided in respect of at least one roll, said attachment comprising bearings separate from said chocks and mounted at each of the ends of said roll, said bearings having radial extensions, hydraulic pressure means arranged on the radial extension of at least one of said bearings, the axis of said pressure means 7 plane of the mill rolls, whereby said rolls are deflected in said plane.

2. In a rolling mill having a housing and chocks for supporting the rolls of the mill in said housings, a rolldeflecting attachment provided in respect of at least one roll, said attachment comprising bearings separate from said chocks and mounted at each of the ends of said roll, said bearingshaving radial extensions, hydraulic pressure means arranged on the radial extension of at least one of said bearings, the axis of said pressure means being parallel to the axis of said roll and tension members parallel to the axis of said roll, each member extending from a point beyond the radial extensions of one of said bearings to a point beyond the radial extension of the other bearing, said pressure means being arranged between said radial extensions and one of the outwardly projecting ends of said tension members, so as to apply couples of forces to both bearings in the common axial plane of the mill rolls, whereby said rolls are deflected in said plane, at least one compression member which takes the reactions to the forces in said tension members, abutments being formed on said bearings, said compression member being in engagement at both its ends with said abutments.

3. A rolling mill according to claim 2 in which said compression member and said abutments have curved contact surfaces.

4. A rolling mill according to claim 2 in which said compression member comprises blocks arranged between the roll-supporting chocks and said abutments.

5. A rolling mill according to claim 2 in 'which said compression member is formed by a rod passing through an axial bore in said roll.

References Cited UNITED STATES PATENTS 381,746 4/ 1888 Wright 72-244 2,897,538 8/1959 Shapiro et al. 72-245 3,250,105 5/ 1966 Stone 72243 3,364,715 1/1968 OBrien 72-241 3,373,588 3/1968 Stone 72237 3,442,109 5/ 1969 Diolot 72240 LOWELL A. LARSON, Primary Examiner

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