Rolling mill with roll bending unit

A rolling mill includes an assembly which can be withdrawn from the two housings. The assembly has two rolls with each roll having a pair of bearing chocks on the roll necks and a pair of further chocks positioned outwardly of the bearing chocks one on each of a pair of extensions of the roll necks. Fluid operable means positioned between the corresponding further chocks permit bending forces in one direction to be applied to the rolls and bending forces in the opposite direction are applied to the rolls by fluid operable means acting between the further chocks of one roll and a reaction member fixed relative to the further chocks of the other roll.

This invention relates to rolling mills which have provision for bending 
the rolls during operation of the mill and to an assembly for use in such 
a mill, the assembly comprising the rolls and the means for bending them. 
It is now well known to provide roll bending facilities on a pair of rolls 
of a rolling mill in order to produce a rolled product having improved 
uniformity in gauge and flatness. The provision for roll bending may be 
provided on a pair of work rolls of a rolling mill or on a pair of back-up 
rolls. Various forms of roll bending have been put forward and some 
schemes need a complicated housing design and others need the provision of 
heavy beams to take the reaction of the roll bending forces and these 
beams necessitate the mill housings being enlarged. Furthermore in the 
known schemes complications can occur at roll changing in that, in many of 
the schemes, the roll changing apparatus has to be dismantled before the 
rolls can be withdrawn from the mill housings. 
It is an object of the present invention to provide an assembly for use in 
a rolling mill in which at least some of the above-mentioned difficulties 
present in the known schemes are overcome. 
It is a further object of the present invention to provide a rolling mill 
which includes such an assembly. 
According to a first aspect of the present invention, an assembly for use 
in a rolling mill comprises first and second rolls each having a roll 
barrel, a roll neck at each end of the barrel, a first bearing chock on 
each neck and a further bearing chock on an extended portion of each neck 
positioned outwardly of the first bearing chock, the rolls being arranged 
one above the other with their longitudinal axes parallel, each of the two 
further chocks on the first roll having a reaction member positioned on 
the side of the corresponding further chock of the second roll which is 
remote from the first roll, fluid operable means positioned between the 
corresponding further chocks of the two rolls and arranged so that on 
being actuated the separation of the further chocks is increased and fluid 
operable means positioned between the reaction member and the further 
chocks of the second roll and arranged so that on being actuated the 
separation of the further chocks is reduced. 
According to a second aspect of the invention, a rolling mill has a pair of 
spaced apart housings each defining a window, a pair of rolls arranged one 
above the other with their longitudinal axes parallel and each supported 
in two bearing chocks located one in each of said windows, and each roll 
having an extension at each end outwardly of the bearing chocks and a 
further bearing chock on each extension, the further bearing chocks at the 
corresponding ends of the rolls having fluid operable means located 
therebetween and arranged such that on being actuated the means urge the 
further chocks apart to apply roll bending forces of one sense to the 
rolls, each of the two further bearing chocks on one of the rolls having a 
reaction member fixed relative thereto and positioned on the opposite side 
of the corresponding further bearing chock of the other roll, and fluid 
operable means located between the further bearing chocks of said other 
roll and the reaction members and arranged such that on being actuated the 
means urge the further bearing chocks towards each other to apply roll 
bending forces of the opposite sense to the rolls. 
In one embodiment of the invention, each reaction member is part of a 
closed loop surrounding the two further chock assemblies at each of the 
corresponding ends of the rolls. Alternatively, however, the reaction 
member may take the form of a U-shaped yoke having one of the further 
bearing chocks mounted across its open end with the other further bearing 
chock movably mounted within the yoke, one of the fluid operable means 
acting between the movable chock and the yoke in the direction towards the 
other bearing chock. 
With such an arrangement, the further bearing chocks at each of the 
corresponding ends of the rolls can be forced apart by applying fluid to 
the operable means located between the bearing chocks thereby providing 
roll bending forces on the rolls or alternatively by applying fluid to the 
other operable means, one of the bearing chocks is urged towards the other 
to apply roll bending forces of the opposite sense to the rolls and the 
reaction is contained within the reaction member. Consequently, no bending 
beams are required in the housings of the mill and no increase in size of 
the housings is necessary. In fact, no significant modification to the 
housing windows of a mill without this roll bending facility is necessary 
in order to provide the roll bending facility on the mill. During roll 
changing, the roll assembly can be withdrawn in situ through the housing 
windows of the mill stand by conventional roll change methods.

Referring to FIG. 1, an assembly 1 suitable for installation in a rolling 
mill comprises a pair of rolls 3, 5 arranged one above the other. Each 
roll has a pair of bearing chocks 6 mounted on the necks of the rolls. 
Each neck has an extension portion and on this extension portion there is 
a further bearing chock positioned outwardly of the bearing chocks 6. The 
further bearing chocks for the roll 3 are indicated by reference numeral 9 
and the further bearing chocks for the roll 5 are indicated by reference 
numeral 11. Each of the bearing chocks 11 has a yoke 13 associated with 
it. The yoke is fixed relative to the chock 11 and is of U-shape and 
passes around the further bearing chock 9 at the corresponding end of the 
roll 3. As will be described later with reference to FIG. 2, the yokes 13 
are pivotally secured to the chocks 11 so that they can be pivoted 
outwardly with respect to the chocks 11 to enable the roll 3 with its 
bearing chocks to be lifted away from the lower roll 5. 
Referring now to FIG. 2, the housing 15 of a rolling mill defines a window 
17. Within the window there are mounted the bearing chocks 6 of the rolls 
3, 5. The bearing chocks are displaceable vertically in the window of each 
housing by means of a hydraulic piston and cylinder assembly 19 located in 
the bottom of each window. 
The yoke 13 can be seen to be of U-shaped form and a pair of blocks 20 are 
positioned inside the open ends of the yoke and each one is pivotally 
secured to the adjacent limb of the yoke by a pivot pin 21. The bearing 
chock assembly 11 has a pair of cut away portions 22 positioned on 
opposite sides which receive the blocks 20 in order to mount the chock 11 
across the open end of the yoke. The further bearing chock 9 is positioned 
within the yoke above chock 11 and has limited vertical movement with 
respect to the yoke. 
Mounted in the upper surface of each of the further chocks 11 are a pair of 
fluid operable piston and cylinder devices 24 which bear against the 
adjacent under surface of the further chock 9. In a similar manner a pair 
of fluid operable piston and cylinders 26 are located in the upper surface 
of the chock 9 and the plungers of the piston and cylinder devices engage 
against the adjacent end of the yoke 13 which serves as a reaction member. 
If the fluid operable devices 26 are not supplied with fluid under pressure 
but fluid under pressure is supplied to the devices 24, then the chock 9 
is urged away from the chock 11. Forces are thus applied to the two rolls 
3, 5 through the bearing chocks 9 and 11 and these forces bend the two 
rolls. The ends of the rolls are forces apart bringing the barrels of the 
two rolls closer together. Alternatively, the piston and cylinder 
assemblies 24 are de-actuated and fluid under pressure in introduced into 
the devices 26, then the chocks 9 are urged towards the chocks 11. This 
again applies bending forces to the two rolls, but in this case the ends 
of the rolls are urged towards each other and the roll barrels are urged 
away from each other. 
In the arrangement shown, the open end of the yoke 13 is closed by the 
bottom bearing chock 11. In an alternative arrangement the yoke could be 
closed by a member which is separate from the chock 11, in which case both 
of the bearing chocks would be contained within a closed loop. In a 
further arrangement, the chocks 11 could be bolted to the side limbs of 
the yokes. 
In the arrangement shown, the rolls are the work rolls of a two-high mill, 
but the invention is applicable also to the back-up rolls of a four-high 
rolling mill. During roll changing, the two rolls with their bearing chock 
assemblies 6, 11 and 9 and the yokes 13 are withdrawn from the mill as an 
assembly. It can be seen from FIG. 2 that the dimensions of the yokes 13 
and the chocks 11 are such that they can readily pass through the windows 
defined by the mill housings. In the arrangement shown, the yokes 13 can 
be pivoted about the pins 21 after the assembly has been removed from the 
mill so that the top roll can be lifted off the bottom roll and the bottom 
roll can then be lifted off the blocks 20.