ROLLING MILL AND METHOD FOR ROLLING A SHEET MATERIAL

Abstract: A rolling mill having a pair of intermediate rolls (13, 14) interposed between a pair of working rolls (1, 2) and a pair of backing rolls (28, 29) so that the intermediate rolls (13,14) are axially displaceable in conformity with the width of a rolled material (3) and the intermediate rolls having bend­ ing means (19 to 22) and guiding members (17) so that the shape of the sheet (3) is controlled by adjusting the axial po­ sition of the intermediate rolls (13, 14) and by exerting bend­ ing forces to the intermediate rolls.

Description: This invention relates to a device for moving the intermediate rolls in the housing of a rolling mill according to JP-A 50-12285. From the DE-A-2 440 495 it is known a rolling mill comprising a device for shifting the intermediate rolls in the axial direction. The intermediate rolls are beared in roll chocks, which are guided in the horizontal and vertical directions on projecting blocks attached inside a window of the mill housing. One of the roll chocks of each intermediate roll is provided with two outer arms. The movable parts of two horizontal cylinder units mounted in the mill housing or in the projecting blocks beneath the window are loosely connected to the end of these arms, so that by applying a pressure fluid to the cylinder units the intermediate rolls will be axially shifted together with its roll chocks. But in this known rolling mill only the work rolls are bent or balanced by bending or balancing rams mounted in the projecting blocks. From the DE-A-2 752 750 are known rolling mills in several embodiments having two work rolls, two intermediate rolls and two backing rolls. In one embodiment all rolls have the same length of working surface and means are provided for bending and/or balancing the working rolls and the intermediate rolls. In an other embodiment the working rolls have a longer effective working surface than the intermediate rolls and the backing rolls. The intermediate rolls are not shiftable in the axial direction and provided with bending means. The JP-50-12 385 discloses a four high rolling mill with shiftable working rolls. Movable blocks are provided between projecting blocks attached inside a window of the mill housing and the working roll chocks. Furthermore, hydraulic rams are engaged with said movable blocks. These features effect that bending forces can be applied to the bearing center of the working roll chocks regardless of the axial shift of the rolls, thereby reducing the wear of the bearings. The object of the invention is to provide a device for always applying a stable and positive roll bending force to the axially movable intermediate roll and to reduce the maintenance time of a rolling mill by prolonging the life of the roll bearings and especially by shortening the time necessary for changing the intermediate rolls. From the JP-B-52-26508 it is known a rolling mill having two stiff back-up rolls, two intermediate rolls and two work rolls each supported in roll chocks. For controlling the shape of the rolled material during the rolling operation the work rolls will be bent by bending means and the intermediate rolls will be shifted in axial direction by shifting devices. Each shifting device comprises two lateral worm gears attached on frames for supporting and guiding the free ends of a traverse. Both roll chocks of the intermediate rolls on the operation side of the rolling mill are provided with two laterally projections and in the middle portion of the displaceable traverse are disposed coupling means having two pivotally hooks for connecting and disconnecting the traverse with the roll chock, so that the shifting movement of the traverse driven by the worm gears will be transferred to the intermediate roll through the roll chock and the roll bearing. All of the worm gears are connected together and to a driving motor by several bevel gear boxes, shafts and clutches, disposed around the rolling mill stands. This object will be solved in a device of the type mentioned above by the features of claim 1. The device according to the invention is simple in the construction and has the further advantage that the bending forces can always be applied to the center of the intermediate roll bearings by locating the rams in position. The changing operation of the roll assembly can be carried out quickly since the movable blocks together with the rams remain in the roll housing. Brief description of the drawings Fig. 1 is a front view of an embodiment of a rolling mill; Fig. 2 is a view taken along a line II-II of Fig. 1. There is provided a pair of working rolls 1 and 2 having a small diameter for rolling a material 3 to be rolled, the working rolls being supported at their ends by metal chocks 4, 5. Each of the metal chocks 4, 5 is disposed for upward and downward movements inside of projections 9, 10, of projecting blocks 7, 8 provided in a window of a roll housing 6 and these projections are provided therein with hydraulic rams 11, 12 for bending the working rolls. There is also provided a pair of intermediate rolls 13 and 14 which are disposed on the upper and lower sides of the working rolls 1 and 2, respectively, and ends of the intermediate rolls are supported by metal chocks 15, 16. Each of the metal chocks 15, 16 is disposed for upward and downward movements inside of movable blocks 17, 18 which are axially movably mounted on the projecting blocks 7, 8, and the movable blocks 17, 18 are respectively provided therein with hydraulic rams 19, 20 for applying an increased bending to the intermediate rolls and with hydraulic rams 21, 22 for applying a decreased bending thereto. The decreased bending of the intermediate rolls is effective to control the compensation for the thermal crown of the rolls. The movable block 17 has attached thereto a cylinder 24 for pivotally moving a keeper plate 23 having a convex portion, while a driving metal chock 15′ for the intermediate roll is provided with a concave portion engaging the convex portion. With such arrangement, if the movable block 17 and the driving metal chock 15′ are connected to each other through the keeper plate 23, the intermediate roll together with the movable block will be able to be axially moved under the action of the cylinder 26. In this case, the intermediate roll chocks and the hydraulic rams 19, 20, 21, 22 are moved together and thus the bending forces can always be applied to the center of intermediate roll bearings 27 by locating the rams in position. Moreover, the intermediate rolls are larger in diameter than the working rolls. There are further provided backing rolls 28 and 29 for supporting the intermediate rolls 13, 14, respectively, the backing rolls being larger in diameter and higher in rigidity than those of the intermediate rolls. Metal chocks 30, 31 for the backing rolls are vertically movably provided in the roll housing. With the arrangement described above, when replacing the intermediate rolls, the keeper plate 23 is released by the hydraulic cylinder 24 to permit the removal of only the roll assembly, while the movable block 17 remains in the roll housing 6.

Claims: A device for moving the intermediate rolls (13, 14) in the housing (6) of a rolling mill having two thinner working rolls (1, 2), two thicker intermediate rolls (13, 14) and two backing rolls (28, 29) and means for bending the working rolls, said device comprising means (17, 26) for axially displacing the intermediate rolls to position the end portions of the roll barrel thereof on or near the vertical lateral edges of the rolled material and comprising projecting blocks (7, 8) attached inside a window of the mill housing (6), whereby movable blocks (17, 18) are disposed between intermediate roll chocks (15, 16) and said projecting blocks (7, 8) so as to guide said intermediate roll chocks (15, 16) on said projecting blocks (7, 8) in the horizontal and vertical direction, hydraulic rams (19 to 22) are engaged with said movable blocks (17, 18) so as to generate forces vertical to said intermediate roll chocks (15, 16) and to apply larger roll bending forces through said roll chocks (15, 16) to said intermediate rolls (13, 14) than the bending forces of the working rolls (1, 2), hydraulic cylinders (26) provided on the housing (6) are connected to the movable blocks (17, 18), keepers (23) (23) are provided for connecting and disconnecting the movable blocks (17, 18) with said roll chocks (15, 16), and a cylinder (24) is mounted on the movable blocks (17, 18) for moving the keepers (23) by means of articulated levers their respective roll chock (15′), the both movable blocks (17) on one side of the rolling mill are connected together by a cross beam and the cylinder (24) is mounted on said cross beam for pivotally moving the keepers (23) to engage said roll chock (15′), and the movable blocks (17) extend between the roll housings (6) on driving and operating sides. The device according to claim 1, characterized in that the movable blocks (17, 18) are horizontally guided on the projecting blocks (7, 8) and said roll chocks (15, 16) are vertically movably disposed on the movable blocks (17, 18). The device according to claim 1 and 2, characterized in that the rams (19 to 22) are disposed in the movable block (17, 18), so that the bending forces are always applied to the center of the intermediate roll bearings (27). The device according to the claims 1 to 3, characterized in that hydraulic cylinders (26) mounted on the housing (6) beneath the window are connected to the movable blocks (17, 18).

Inventors: KAJIWARA, TOSHIYUKI
Applicants: HITACHI, LTD.
Application year: 1980
Main classification: B21B13
IPC codes: B21B13, B21B37, B21B27, B21B31, B21B29