US3318131A - Multiple-roll rolling mill for exchangeable work rolls of substantially varying diameter - Google Patents

Description

May 9, 1967 K. J. NEUMANN MULTIPLE-ROLL ROLLING MILL FOR EXCHANGEABLE WORK ROLLS OF SUBSTANTIALLY VARYING DIAMETER 2 Sheets-Sheet 1 Filed Nov. z, 1964 mm a 5 am R mm R w May-9., 1967 K. J. NEUMANN 3,313,131

MULTIPLE-ROLL ROLLING MILL FOR EXCHANGEABLE WORK ROLLS OF SUBSTANTIALLY VARYING DIAMETER Filed Nov. 2, 1964 2 Sheets-Sheet 2 Fig. 2

United States Patent 3,318,131 MULTIPLE-ROLL ROLLING MlLL FOR EX- CHANGEABLE WORK ROLLS 0F SUBSTAN- TIALL'Y VARYING DIAMETER Karl Josef Neumann, St. Ingbert, Saar, Germany, as-

signor to Verwaltangsgesellschaft Mueller & Neumann ofiene Handelsgesellschaft, St. Inghert, Saar, Germany Filed Nov. 2, 1964, Ser. No. 408,427 Claims priority, application Germany, Oct. 31, 1963, V 24,787 5 Claims. (Cl. 72-243) The invention relates to a cold rolling mill having more than four rolls, especially to a so-called multiple-roll rolling mill for rolling thin sheets or strips. It is known that the thinnest strip thickness which may be rolled on a cold rolling mill determines the diameter of the working rolls. Thick working rolls of a four-high rolling mill allow substantial pass reductions but roll only down to a strip thickness at which the roller flattening, due to the solidification of the strip, becomes greater so that even with an increased rolling pressure no further noticeable reductions can be obtained. In the case the strip is to be rolled even thinner, or in the case where a hard material is worked, one must use a multiple-roll rolling mill having small diameter working rolls.

It is therefore an object of this invention to provide a multiple-roll rolling mill which has the advantage of a four-high rolling mill with thick work rolls, that is to say large pass reductions at the beginning of the rolling operation of a strip are combined with the advantages of a multiple roll rolling mill having thin or small diameter working rolls, namely the possibility of a further rolling also of hard strips down to the smallest strip thicknesses.

It is a further object of the invention to provide a multiple-roll rolling mill for inserting working rolls of substantially varying diameter.

Multiple-roll rolling mills are already known in which instead of a two-high or four-high roll set also roll sets having thin work rolls are built-in and in which the thick work rolls are supported on the sides by a series of additional backing rolls. While in the case of a four-high operation the thick work rolls are driven it is necessary to change the drive to the backing rolls upon a transition to thin work rolls.

It is a further object of the invention to maintain the coupling of the driving spindles with the driven rolls in the case where the rolling operation is changed from thin or small diameter working rolls to thick or large diameter working rolls. By thick working rolls are to be under: stood those which have a diameter comparable to the usual Working roll diameters employed in four-high rolling mills.

The objects of the invention are to be accomplished with the smallest possible number of rolls. The best known multiple-roll rolling mill presently has twenty rolls.

Contrary to this the rolling mill according to the invention should comprise not more than ten rolls.

The invention is based on a multiple-roll rolling mill having on both sides of the rolling gap roll sets comprising each an equal amount of rolls, and each set consisting of a working roll, two driven intermediate rolls and two backing rolls for absorbing the forces received by the intermediate rolls, wherein the intermediate rolls are mounted in chocks which are guided radially of the axial center lines of the backing rolls. Based on the knowledge that in the case of such a ten-roll rolling mill whose rolls are disposed in an X-arrangement as disclosed in British Specification 870,777 the varying forces resulting from the rolling pressure, the driving moment and the strip tension, which act on the intermediate rolls and depending on the diameter of the working rolls, must be taken up without additional intermediate or backing rolls by the inclined guides of the intermediate roll chocks, it is the purpose of the invention to eliminate the force components resulting from the rolling pressure and having the effect of a bearing pressure in the intermediate roll chocks as it is the case in a four-high rolling mill. This is to be expected when in each working roll diameter the axis center lines of the intermediate rolls each are adjusted to the inclined connection lines between the axis center lines of the associated working roll and of the backing roll against which the intermediate roll bears. This adjustment is obtained according to the invention in that the guides for the chocks of the driven intermediate rolls consist of pivot elements which are movable around the axis center lines of these backing rolls both symmetrically in that the horizontal distance of the intermediate rolls from each other is adjustable by means of a displacing device which engages directly or indirectly at the pivot elements in the same pivot direction to set the axial center lines of the intermediate rolls unsymmetrically out of alignment with the connection lines between the working roll and the axial center of the backing rolls.

In the simplest embodiment of a rolling mill according to the invention the pivot element of each backing roll may be displaced individually or in pairs of superimposed backing rolls together. In this manner one is able to adjust the pivot elements of a pair of intermediate rolls which drive a work roll unsymmetrically to the vertical plane running through the axis center lines of the work rolls in order to produce in the intermediate roll chocks a force component resulting from rolling pressure directed against the bearing pressure in the intermediate roll chocks, which equals the resulting bearing pressure derived from the driving rotation moment and the strip tension which engages at the two driven intermediate rolls in the same horizontal direction. This is obtained by the individual displacement of the axis center lines of the intermediate rolls laterally of and out of alignment with the mentioned inclined connection line between the working roll center and the backing roll center, called hereafter articulated position.

In this manner it is obtained that from the intermediate rolls only forces directed radially to the backing roll axis center lines are transferred and that the forces which exert on the pivot elements a rotating moment to be absorbed by the displacing device disappear.

From a construction view point it is advantageous to make the pivot elements adjustable relative to each other symmetrically to the vertical plane which runs through the center lines of the Working rolls so that rotating moments are constantly effective at the pivot elements whereby the adjusting parts remain loaded. In order to displace also in the case of a symmetrical displacement of the intermediate rolls opposite to each other, which is to be carried out upon a transistion to another working roll diameter, the intermediate roll axis center lines laterally away from the connection lines between the working roll and backing roll axis center lines for setting the articulated position, whereby the forces arising from the rolling pressure at the intermediate rolls are directed against the forces resulting from the driving rotation moment and the strip tension, the invention provides that the pivot elements are also pivotable in a displacement in the same direction of rotation.

As the forces resulting from the driving moment and the strip tension which are effective at the intermediate rolls change their direction with each reversing pass, the invention purposes that the pivot elements may be switched over with each reversing pass in the same pivot direction, namely between two predetermined pivot positions which are symmetrical to the inclined connection line of the axis center lines of the associated backing rolls and working rolls.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawings which illustrate an embodiment of the invention.

FIGURE 1 shows the lower roll set of a ten-roll rolling mill with an adjusting device for the pivot elements, the roll set in side view and the displaying device in crosssection.

FIGURE 2, a cross-section along line II-II in FIG- URE 1 showing parts of the roll assembly with a pivot element and FIGURE 3, a roll asembly including the composition of forces.

As may be seen with reference to FIGURE 1, the roll set consists of a working roll 1, two intermediate rolls 2, 3 engaging the working roll, and of two large backing rolls 4 and 5. The intermediate rolls 2, 3 are driven by suitable means (not shown). For setting the position of the intermediate rolls 2, 3 they are mounted in chocks 6, 7 which are guided by bolts 8, 9 in cross bores 10, 11 of the backing roll shaft 4a, a radially to the axis center line 4b, 5b of the backing rolls, so that the intermediate rolls bear always against the backing rolls even after some wear. The pivot elements 12, 13 are secured on the backing roll shafts 4a, 5a at both ends, for example by a shrunk-fit, and these pivot elements extend the guide bores 10, 11 for the bolts 8, 9.

The horizontal distance between the intermediate rolls may be varied in opposite direction to each other with respect to the vertical center plane 14 by a symmetrical pivoting of the pivot elements 12, 13. This displacement is carried out when instead of the thin work roll 1, which in the embodiment shown, has a diameter of 80 mm., a thick working roll 15 shown in dot-and-dash lines and having a diameter of 250 mm. is to be inserted. The intermediate rolls are then moved into the positions 2a, 3a, shown in dot-and-dash lines, in which positions the axis center lines of the intermediate rolls are located on the inclined connection lines 16, 17 between the axis center lines of the working roll 15 and on the axis center lines 4b, 5b of the backing rolls 4, 5. This position of the intermediate rolls in alignment with the axis center lines of the adjacent rolls Will be called hereafter the neutral position.

In inserting thick work rollers the roll sets of the rolling mill are to be separated from each other a corresponding amount by a screw-down device (not shown). In the case of a ten-roll rolling mill the screw-down distance is to be so measured that instead of thick working rolls 51 for rolling down a strip thin working rolls 1 of less than half the diameter of the thickest working rolls 15 may be inserted.

The backing rolls 4 and 5 consist of stationary shafts 4a, 5a with individual roller bearing rings "19 mounted in spaced relationship. The shafts 4a, 5a are mounted on both sides of the bearing rings 19 in common frames 18. By means of this known type of backing roll construction having thick shafts it is possible, according to the invention, to provide the displacement devices for pivoting and setting the pivot elements 12, 13 only on one side of the roll sets, as the pivot elements on the other side of the torsion resisting backing roll shafts 4a, 5a are also coupled to them non-rotatably and follow the rotation.

In order to adjust the pivot movements of the pivot elements 12, 13 moving in opposite directions or in the same directions in a simple manner, the invention provides for each roll set displacement devices which comprise displacement elements which may be driven in opposite directions or in the same directions and which may be fixed in position.

The drawing shows a displacement device which has the advantage of not requiring any linkage parts and which may be so tensioned that during the rolling operation no play can be effective in the displacement parts. For displacing each pivot element 12 or 13 of a roll set a setting cylinder 21, 22 respectively is provided which may be displaced in the axial direction, these setting cylinders being guided in the embodiment illustrated in a common guide cylinder 20. The setting cylinders 21, 22 each receive a pair of pistons having pistons 23, 24, and 25, 26 which may be moved back and forth hydraulically in pairs in the same direction. These piston sets engage on each side a lever arm 12a or 13a of the pivot elements 12 and 13. Between the lever arms and the piston pairs an articulated connection is provided at which the lever arms carry ball-shaped recesses 1212 or 1312 and the pistons 23 to 2d ball-shaped pressure parts 27. The pistons 23, 24 may be put under pressure over hydraulic conduits 28 and 29 in the opposite direction by hydraulic pressure so that the joints at the lever arms 12a and 13a are always without play. In the illustrated neutral position of the intermediate rolls 2 on the connection line between the axis center line of the work roll 1 as well as of the backing roll 4 both pistons 23 and 24 have a small axial play relative to the cylinder covers 2111 of their common cylinders 21. This axial play makes it possible to displace by alternate admission of pressure against the one or the other piston 23 or 24 through conduits 28, 29 the lever arm 12a of the pivot element 12 and thus also the intermediate roll 2 toward the one or the other side from the neutral position. The same hydraulic displacement in the same direction is also provided by the pistons 25, 26, which are displaceable over hydraulic conduits 30, 31 through the axial play s relative to their stationary cylinder 22.

- movements of cylinders 21, 22 inwardly may be carried out, when the pressure in pressure chamber 33 is cut off. After each displacement of the cylinders 21, 22 over the stop spindles 34, 35 pressure is again generated .in pressure chamber 33 in order to make the mechanism of the displacement device free of play. In order to fix the stop spindles 34, 35 hand wheels 38, 39 are provided in order to counter the thread connection.

It is to be understood that a displacement device for pivot elements 12, 13, described herebefore, must also be provided at the upper roll set of the ten-roll rolling mill (not illustrated).

The operation of the ten-roll rolling mill of the invention as well as the possible working processes and their operation will now be explained in greater detail:

The setting 0 the intermediate rolls In FIGURE 1 the intermediate rolls 2, 3 for the bearing of the very thin working roll 1 are set to a minimum distance from each other. Before inserting a thicker working roll 15 it is necessary to swing the pivot elements 12, 13 in opposite directions outwardly to such an extent that the intermediate rolls 2, 3 move into the position 2a, 3a shown in dot-and-dash lines, in which symmetrical position their axis center lines lie on the connection lines 16 and 17 between the axis center lines of the Working roll 15 and the backing rolls 4 and 5. The axis center lines of the intermediate rolls move on arcs 40 and 41 during this displacement. The setting position is released in that first the counter hand wheels 33, 39 are loosened and the cylinders 21, 22 are brought closer to each other 5 by threading in the stop spindles 34, 35. During this operation the pressure in the chamber 33 must be let off temporarily. It is to be understood that instead of the manual operation also a motor drive may be provided for the stop spindles 34, 35. The correct adjustment of the cylinders 21, 22 corresponds to the diameter of the new working roll 15 and may be determined from a dial (not shown).

The setting the intermediate rolls to the articulated position Before the setting of the pass reduction of the first pass with inserted strip by the screw-down device acting on the upper roller set (not shown) for a rolling direction as shown in FIGURE 3 going from left to right the pressure lines 28 and 31 are connected with the pressure source, and the pressure conduits 29, 30 are switched in reverse. Thereby the piston pairs 23, 24- and 25, 26 are displaced toward the right by their axial play s, so that the intermediate rolls 2 and 3 move into the full line articulated position according to FIGURE 3. In this articulated position the intermediate rolls 2 and 3 are displaced with respect to the connection lines 16, 17 of the neutral position opposite to the rolling direction. This articulated position of the driven intermediate rolls 2, 3 reduces the forces which are produced from the driving rotating movement and the strip tension and which act as rotating moment on the pivot elements 12, 13. According to the invention the displacement of the axis center lines of the intermediate rolls 2, 3 is switched over beyond the neutral position opposite to the new rolling direction with respect to the changing direction of the forces which occurs during the reversing before each reversing and before each pass reduction by the screwdown device. The new position of the intermediate rolls is shown in FIG. 3 in dash-and-dot lines. For this position the pressure conduits 29, 30 are simply connected to the pressure source and the pressure conduits 28, 31 are switched to reversing. Upon a change-over of the articulated position the piston pairs 23, 24 and 25, 26 therefore move in the same direction, in each case double the amount of their axial play s. As each piston abuts alternately against the cylinder covers 21a depending on the articulated position and as thehydraulic pressure bears on the oppositely located piston the joints between the pistons 23 to 26 and the pivot elements 12, 13 or their lever arms 12a, 13a remain loaded.

In order to determine the end positions of the articulated positon one must investigate the forces which arise in the system. In the force plan according to FIGURE 3 the intermediate rolls 2, 3 are displaced for the rolling direction from left to right opposite to the rolling direction relative to the connection line 16, 17 of the neutral position. The rolling force P is divided into the unequal components P and P which are directed to the axis center lines of the intermediate rolls 2, 3 and into two components which are directed perpendicularly thereto, which are not of interest in this connection. With reference to the intermediate rolls the components P and P may again be divided into forces P or P directed to the axis center lines 4b, 5b of the backing rolls and into forces P or P which are perpendicular thereto. It is these forces which exert-' over the checks 6, 7 of the intermediate rolls 2, 3 as hearing pressure a rotation moment on the pivot elements 12, 13 where no equal oppositely directed forces oppose them.

The opposiing forces are derived from the peripheral forces which engage at the driven intermediate rolls, namely the forces P and P resulting from the driving rotation moment and the strip tension as well as the forces P and P resulting from the roll friction moments between the intermediate rolls and the backing rolls as well as from their roller bearings. By parallel displacement of these forces P and P identified hereafter as buckling forces result by subtraction of the smaller P -forces from the always larger P -forces counterforces P and P which are directed opposite to the buckling forces P and P In the force plan according to FIG. 3 the conditions are assumed to be such that the buckling force P for the intermediate rolls 3 is equal to the counterforce P Therefore no rotation moment which would have to be taken up by the displacement device is exerted on the pivot element 13.

As for the other intermediate roll 2 the counterforce P is equal to P but the buckling force P is smaller due to the outwardly directed articulated position (P smaller than P A remaining force is effective at the intermediate roll 2 which tends to drive the intermediate roll 2 inwardly. This remaining force is absorbed over the piston 23 by the pressure means when the pressure conduit 28 is closed.

As embodiment of this working process it is assumed that a strip is to be rolled with a constant rolling pres sure of P equals 1000 t. The driving rotation moment is assumed to be 2830' mkg. at the first pass, the strip tension 12 t. It is further assumed that the forces P and P resulting from the driving rotation moment and the strip tension, which always act against the rolling direction on the intermediate rolls 2, 3 and are calculated for the first pass as 16,200 kg. becomes smaller from pass to pass, namely in the ratio 4:1, calculated from the first to the last pass. At the last pass the forces P and P are therefore 4050 kg. The end positions of the articulated positions of the intermediate rolls are now so chosen that the buckling forces P and P amount on the average to about two and a half times the smallest P -forces of 4050 kg., thus 10,200 kg. If six passes are assumed and the P -forces decrease from 16,200 kg. linearly to 4050 kg. the following table is obtained:

PAR= AR, a= aZ AR- PAnPa,

It will be observed that the remaining forces which would engage at the axis center lines of the intermediate rolls 2, 3 are at a maximum at the first and last pass and tend due to their opposite directions in the middle passes, to a minimum. By the working process described the maximum remaining forces which arise are kept small.

What is claimed is:

1. Multiple-roll rolling mill including two sets of rolls on both sides of the rolling gap; each roll set comprising a work roll of small diameter, two driven, horizontally spaced intermediate rolls engaging said work roll and two horizontally spaced backing rolls arranged at a fixed distance from one another for engaging each one of said two intermediate rolls; said intermediate rolls being supported in checks carried on guide means mounted for adjustment radially of the axial center lines of said backing rolls, said guide means including pivot elements movable about the axial center lines of said backing rolls; a diplacement device for moving said pivot elements both symmetrically to change the horizontal distance of said intermediate rolls from each other for adapting said distance to the actual working roll diameter, and in the same pivot direction to set the axial center lines of said intermediate rolls unsymmetrically and out of alignment with the connection lines between the axial center of the working roll and the backing rolls. to absorb the components force resulting from the rolling pressure, the driving rotation moment and the strip tension, taken up by said pivot elements.

2. Multiple-roll rolling mill according to claim 1 in which the amount of horizontal spacing of said intermediate rolls is adapted for inserting selectively thick and thin work rolls for cold Working operation, each said thick Work roll having a diameter more than twice the diameter of each said thin Work roll.

3. Multiple-roll rolling mill according to claim 2 in which said displacing device for one pivot element consists of a setting cylinder movable in an axial direction containing two pistons hydraulically reciprocable in the same direction, said pistons engaging in pairs a lever arm of said one pivot element on opposite sides.

4. Multiple-roll rolling mill according to claim 3 in which the setting cylinder is guided like a piston in a stationary guide cylinder which forms on one side of the setting cylinder a pressure chamber for introducing pressure fluid means whose pressure loads a mechanically operated setting device at the other side of the setting cylinder.

5. Multiple-roll rolling mill according to claim 4 in which said setting cylinders for moving said pivot elements of a roll set are disposed in a common guide cylinder and form between them said pressure chamber for loading adjustable stop spindles which act from the outside against said setting cylinders.

References Cited by the Examiner UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner.

E. M. COMES, Assistant Examiner.

Claims (1)

1. MULTIPLE-ROLL ROLLING MILL INCLUDING TWO SETS OF ROLLS ON BOTH SIDES OF THE ROLLING GAP; EACH ROLL SET COMPRISING A WORK ROLL OF SMALL DIAMETER, TWO DRIVEN, HORIZONTALLY SPACED INTERMEDIATE ROLLS ENGAGING SAID WORK ROLL AND TWO HORIZONTALLY SPACED BACKING ROLLS ARRANGED AT A FIXED DISTANCE FROM ONE ANOTHER FOR ENGAGING EACH ONE OF SAID TWO INTERMEDIATE ROLLS; SAID INTERMEDIATE ROLLS BEING SUPPORTED IN CHOCKS CARRIED ON GUIDE MEANS MOUNTED FOR ADJUSTMENT RADIALLY OF THE AXIAL CENTER LINES OF SAID BACKING ROLLS, SAID GUIDE MEANS INCLUDING PIVOT ELEMENTS MOVABLE ABOUT THE AXIAL CENTER LINES OF SAID BACKING ROLLS; A DISPLACEMENT DEVICE FOR MOVING SAID PIVOT ELEMENTS BOTH SYMMETRICALLY TO CHANGE THE HORIZONTAL DISTANCE OF SAID INTERMEDIATE ROLLS FROM EACH OTHER FOR ADAPTING SAID DISTANCE TO THE ACTUAL WORKING ROLL DIAMETER, AND IN THE SAME PIVOT DIRECTION TO SET THE AXIAL CENTER LINES OF SAID INTERMEDIATE ROLLS UNSYMMETRICALLY AND OUT OF ALIGNMENT WITH THE CONNECTION LINES BETWEEN THE AXIAL CENTER OF THE WORKING ROLL AND THE BACKING ROLLS TO ABSORB THE COMPONENTS FORCE RESULTING FROM THE ROLLING PRESSURE, THE DRIVING ROTATION MOMENT AND THE STRIP TENSION, TAKEN UP BY SAID PIVOT ELEMENTS.

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