ROLLING MILL STAND

Abstract: A rolling mill stand has a pair of work rolls which are movable axially. At least one of the rolls has a pair of rams attached to the mill housing and having a part displaceable in the direction of the length of the roll. The displaceable part of the ram is engageable with, and disengageable from, the bearing chock assembly at one end of the roll in order to axially displace the roll.

Description: ROLLING MILL STAND This invention relates to a rolling mill stand in which at least one of its pair of work rolls is displaceable to a limited extent in the direction axially of its length. Conveniently, both the work rolls are displaceable axially to a limited extent. During the rolling of metal strip, it is desirable to be able to move the work rolls in the direction of their longitudinal axis in order to spread out the wear on the rolls which occurs during a period of rolling. According to the present invention, a rolling mill stand comprises a pair of spaced apart housings each defining a window; a pair of work rolls each supported by a pair of bearing chock assemblies located in respective housings windows; and characterised in the provision of a pair of rams each secured to one of the housings on opposite sides of the window and having a part displaceable in the direction parallel to the longitudinal axes of the rolls; said displaceable part of each ram having means which is engageable with, and disengageable from, co-operating means on one of said bearing chock assemblies whereby displacement of the parts of the rams, while the means are engaged with the co-operating means on the bearing chock assembly, causes the bearing chock assembly and, hence, the roll to be displaced in the axial direction of the roll. Conveniently, each work roll has a pair of rams each secured to one of the housings on opposite sides of the window and having a part displaceable in the direction parallel to the longitudinal axes of the rolls, said displaceable part of each ram having means which is engageable with, and disengageable from, co¬ operating means on one of the bearing chock assemblies of the roll whereby displacement of the parts of the rams, while the means are engaged with the co-operating means on the bearing chock assembly, cause the bearing chock assembly and, hence, the roll to be displaced in the axial direction of the roll. The co-operating means on the bearing chock assembly for the or each ram comprises a plurality of co-operating means arranged successively in the direction parallel to the longitudinal axes of the rolls whereby successive displacement of the parts of the ram, while the means are engaged in turn with the co-operating means, causes the bearing chock assembly and, hence, the roll to be displaced in the axial direction of the roll by a distance which is greater than the stroke of the ram. The co-operating means on the displaceable parts of the rams and on the corresponding bearing chock assembly allow the bearing chock assembly and, hence, the roll which is supported in it to be displaced parallel to the longitudinal axis of the roll. By enabling the co-operating means to be disengaged, the bearing chock assembly can be moved relative to the corresponding rams as, for example, at the time for changing the rolls. The co-operating means conveniently take the form of latches mounted on the displaceable part of the rams and engageable with slots on the bearing chock assembly. By engaging the co-operating means on the displaceable parts of the rams and on the bearing chock assembly, the bearing chock assembly and, hence, the roll which is supported in it can be displaced parallel to the longitudinal axis of the roll. By disengaging the co-operating means in the displaceable parts of the rams from one of said co-operating means on said bearing chock assembly and connecting the co¬ operating means with a second co-operating means on the bearing chock assembly, a further displacement of the bearing chock assembly can be made. By successively engaging the co-operating means on the bearing chock assembly, a displacement of the bearing chock assembly and, hence, the roll can be made which is greater than the stroke of the rams. In one embodiment of the invention, the latches are mounted on the displaceable cylinders of the rams and means are provided for rotating the cylinders with respect to their pistons so that the latches can be engaged with, and disengaged from, the grooves on the bearing chock assembly. The cylinders of the first and second sets of rams may also include spindle supports which, when the cylinders of the first and second sets of rams are disengaged from the bearing chock assemblies, are positioned so as to support a drive spindle which is disconnected from the adjacent end of the work rolls. In this way, the spindles are supported in the correct location ready to receive the roll ends of the replacement rolls. In order that the invention may be more readily understood, it will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a sectional plan view of part of a rolling mill stand in accordance with the present invention, the right-hand side of the drawing showing the apparatus in the roll change position and the left- hand side of the drawing showing the rolling mill stand in its operative position; Figure 2 is a diagrammatic end elevation of part of the apparatus shown in Figure 1; and Figure 3 is a sectional plan of an alternative embodiment. A rolling mill stand has a pair of work rolls 1, 3 supported at their ends in bearing chock assemblies 5, 7, respectively. The bearing chock assemblies at one corresponding end of the rolls are located in a window 9 in a housing 11 and the bearing chock assemblies at the other end of the rolls are similarly supported in the window of a mill housing (not shown). The rolls are driven by a pair of spindles 13, one of which is shown in Figure 1. The end of each spindle carries a coupling 15 by which the spindle can be releasably connected to the end of the corresponding work roll. A pair of hydraulically operated rams 17 are mounted on the housing 11 on opposite sides of the longitudinal axis of the upper work roll 1. A similar pair of hydraulic rams 19 are mounted on the same housing 11 on opposite sides of the longitudinal axis of the lower work roll 3. Each of the rams 17, 19 has a cylinder structure 21 with a piston structure 23 within it. The outer end of the piston structure is rigidly secured to the housing 11. By applying hydraulic fluid to the cylinders 21, the cylinders can be caused to move in the axial direction of the pistons 23 and the pistons are arranged so as to extend parallel to the longitudinal axes of the work rolls 1, 3. The cylinder structure of each ram is rotatable relative to the longitudinal axis of its piston and it carries a lug 25 and a latch 27. The latch co-operates with a recess or slot 29 formed in an extension 31 of the appropriate bearing chock assembly. Hence, by rotating the cylinder structure of the ram, the latch 27 can be engaged with, or disengaged from, the recess 29 thereby either connecting the ram and the bearing chock assembly or disconnecting them. When the latches are engaged with the recesses, displacement of the cylinder structures causes the bearing chock assembly to be displaced in the direction of the roll axis from the position shown on the left-hand side of Figure 1 to that shown on the right-hand side of the figure. Rotation of each cylinder structure is brought about by a rack and pinion device 33 and the two rams on one side of the vertical plane containing the roll axes are connected to one rack 33 and the pair of rams on the opposite side of the vertical plane containing the roll axes are connected to a separate rack 33. By displacing the racks 33 in a vertical direction by a piston-cylinder device secured to the upper end of each rack, the cylinder structures can be rotated to engage or disengage their latches 27 in the appropriate recesses 29. The cylinder structure of each ram also carries a support 35 for a spindle coupling 15. When the latches 27 are disengaged from the recesses 29, the two spindle supports are arranged in a position where the spindle coupling can readily be supported. As shown on the left-hand side of Figure 2, however, when the latches are engaged in the recesses, the spindle supports 35 are not in a locating position. In use, the racks 33 are operated to rotate the cylinder structures so that the latches of all the rams are engaged in the corresponding recesses. When fluid is applied to the cylinder structure, the cylinders are displaced relative to the pistons and the bearing chock assemblies and the rolls are displaced in the direction axially of the rolls. The bearing chock assemblies slide on beams 37. When the rolls are to be changed, the cylinders are rotated so as to disengage the latches from the recesses and to position the supports 35 ready to receive the spindle couplings. The couplings are removed from the rolls, the couplings supported on the supports and the rolls are withdrawn from the housings. In the arrangement shown in the figures, the cylinder structures are rotated with the aid of racks 33 which engage with toothed parts of the cylinder structures. Clearly, other means could be employed to rotate the cylinder structures. For example, electric or hydraulic motors could be employed either directly or indirectly. Referring to Figure 3, which has some parts very similar to what is shown in Figures 1 and 2, the end of each work roll adjacent the housing 101 is the drive side of the mill stand and a drive shaft is removably connected to this end of the work roll. At the other side of the mill stand, a pair of hydraulically operated rams 113 are mounted on the housing 103. Each ram has a piston 115 which is connected at its outer end to the mill housing and a cylinder 117 surrounds part of the piston. When fluid is introduced into the cylinder, the cylinder moves relative to the piston in a direction parallel to the longitudinal axis of the top roll. The cylinder 117 is rotatable with respect to the piston 115 and an operating rod 119 is connected to one side of the cylinder to enable a limited angular rotation to be applied to the cylinder. On the other side of the cylinder there is a latch 121. This latch co-operates with grooves 123 formed on an extension 125 of the bearing chock assembly at that end of the roll. The extension of the bearing chock assembly extends in the direction parallel to the longitudinal axis of the roll and the grooves are spaced apart in the direction parallel to the longitudinal axis of the roll. In Figure 3, the right-hand side of the drawing shows the upper work roll in its normal operating position and the left-hand side of the drawing shows the work roll after it has been axially displaced. Referring to the position shown on the right-hand side of the drawing, the latch 121 of each ram is located in the groove 123 which is furthest from the housing 103. When the rams 113 are actuated, the cylinders 117 are displaced by the full stroke of the rams and the bearing chock assembly is also displaced by an amount equal to the displacement of the rams. The cylinder of each ram is then rotated by the operating rod 119 in order to disengage the latch from the groove. The rams are actuated to allow the cylinder to move relative to the piston. The cylinder is rotated to engage the latch with the adjacent groove 123 and the rams are actuated again in order to displace the bearing chock assembly and, hence, the roll by a further distance equal to the stroke of the rams. The procedure is then repeated and the latches 121 are engaged with the grooves which are closest to the housing 103 and, again, the displacement of the cylinder of each ram causes further axial movement of the roll. Consequently, a series of operations of the rams can produce an axial displacement of the roll by a distance which is greater than the stroke of each ram. The displaced position of the work roll is shown on the left-hand side of Figure 3. Each of the rams may have a linear transducer associated with it so that the exact position of the bearing chock assembly and, hence, the work roll can be determined. The sequential movements of the rams and the co-operating parts on the bearing chock assemblies can be controlled by a computer-based control system. Although in the arrangement shown in Figure 3 the rams are on the opposite side of the mill to the drive side, where spindle positions allow the rams can be positioned on the drive side of the mill. In Figure 3, the rams are shown associated with the upper work roll and a similar arrangement of rams co-operating with the bearing chock assembly of the lower work roll could also be provided. All the rams could be operated simultaneously so that the two rolls are displaced together or the rams associated with one of the rolls could be operated independently of the rams associated with the other roll so that the rolls move independently of each other. In the arrangement shown in Figure 3, the co¬ operating means on the rams co-operate with means on the bearing chock assembly. In an alternative arrangement, each bearing chock assembly is supported on a pair of axially slidable blocks and the co¬ operating means on the rams co-operate with the slidable blocks to displace the blocks and, hence, the bearing chock assembly.

Claims: Claims : 1. A rolling mill stand comprising a pair of spaced apart housings each defining a window; a pair of work rolls each supported by a pair of bearing chock assemblies located in respective housings windows; and characterised in the provision of a pair of rams each secured to one of the housings on opposite sides of the window and having a part displaceable in the direction parallel to the longitudinal axes of the rolls; said displaceable part of each ram having means which is engageable with, and disengageable from, co-operating means on one of said bearing chock assemblies whereby displacement of the parts of the rams, while the means are engaged with the co-operating means on the bearing chock assembly, causes the bearing chock assembly and, hence, the roll to be displaced in the axial direction of the roll. 2. A rolling mill stand as claimed in claim 1, characterised in that each work roll has a pair of rams each secured to one of the housings on opposite sides of the window and having a part displaceable in the direction parallel to the longitudinal axes of the rolls, said displaceable part of each ram having means which is engageable with, and disengageable from, co¬ operating means on one of the bearing chock assemblies of the roll whereby displacement of the parts of the rams, while the means are engaged with the co-operating means on the bearing chock assembly, cause the bearing chock assembly and, hence, the roll to be displaced in the axial direction of the roll. 3. A rolling mill stand as claimed in claim 1 or 2, characterised in that the co-operating means on said bearing chock assembly comprises for each ram a plurality of co-operating means arranged successively in the direction parallel to the longitudinal axes of the rolls whereby successive displacement of the parts of the ram, while the means are engaged in turn with the co-operating means, causes the bearing chock assembly and, hence, the roll to be displaced in the axial direction of the roll by a distance which is greater than the stroke of the ram. 4. A rolling mill stand as claimed in claim 1, 2 or 3, characterised in that the piston of each ram is secured to the housing and the cylinder of each ram is the displaceable part. 5. A rolling mill stand as claimed in claim 4, characterised in that the means on the cylinder of each ram is a latch and the or each co-operating means on the bearing chock assembly is a slot. 6. A rolling mill stand as claimed in claim 5, characterised in that the cylinder of each ram is rotatable relative to the piston and means are provided to rotate the cylinder in one direction to insert the latch in a slot and to rotate the cylinder in the opposite direction to withdraw the latch from a slot. 7. A rolling mill stand as claimed in claim 6, characterised in that the means for rotating the cylinder is a rack displaceable in the direction of its length and engageable with a pinion associated with the cylinder. 8. A rolling mill stand as claimed in claim 5, 6 or 7, characterised in that the cylinder of each ram carries a support for a spindle, said support being in spindle supporting position when the cylinder is disengaged from the bearing chock assembly.

Inventors: LISTER MICHAEL, MARSHALL ROBERT, TAYLOR LEONARD GUY, LISTER, MICHAEL, MARSHALL, ROBERT, TAYLOR, LEONARD, GUY
Applicants: DAVY MCKEE SHEFFIELD, DAVY MCKEE (SHEFFIELD) LIMITED
Application year: 1988
Main classification: B21B31
IPC codes: B21B31, B21B35