Abstract:
A rolling mill has upper and lower rolls with axes which cross each other. These two rolls are pivoted at ends diametrically opposite to each other. Only rolls chocks mounted at the non-pivoted ends of the rolls are allowed to be hydraulically moved the same distance in the same direction, i.e., the rolling direction or the reverse direction, in a symmetrical relation with respect to the center line of the rolling mill.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cross-rolling mill having upper and lower rolls which are inclined at a small angle to each other and between which a strip is passed to roll the strip. 
     2. Description of the Related Art 
     As shown in FIG. 4, the axes of the upper and lower rolls of a prior art cross-rolling mill intersect each other at a point. Roll chocks mounted on the work side see (FIG. 3) and on the driver side, respectively, moved so that the intersection point is maintained on the center line (see Japanese Patent Laid-Open Nos. 195521/1982 and 64908/1980). In the prior art rolling mill, the two roll chocks are simultaneously moved to cause the axes of the upper and lower rolls to cross each other. Hence, the structure is complex and expensive to manufacture. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a rolling mill that is simple in structure and requires less maintenance than conventional rolling mills. 
     The above object is achieved by a rolling mill in which each of the upper and lower rolls is movable only about one end thereof which allows the axes of the two rolls cross each other. That is, when the rolls are moved, if the chock on the work side of the upper roll is pivoted, then the chock on the driver side of the lower roll is pivoted. 
     The movement of the axes of the rolls is shown in FIG. 1. Driver devices are provided to move each roll about its one end. When the driver devices are operated, the intersection point of the axes moves on the center line but does not leave it. Thus, the axes of the upper and lower rolls intersect each other. Therefore, the shape of the rolled strip can be controlled by varying the distance between the upper and lower rolls in a symmetrical relation with respect to the center line. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation of the rolls of a cross-rolling mill according to the present invention, showing the arrangement of the rolls; 
     FIG. 2(a) is a plan view partially in cross section of the upper roll of the mill depicted in FIG. 1; 
     FIG. 2(b) is a plan view partially in cross section of the lower roll of the mill depicted in FIG. 1; 
     FIG. 2(c) is a schematic illustrating an alternative system for crossing operation of the rolls; 
     FIG. 3 is a view similar to FIG. 2(a), but showing a prior art cross-rolling mill in which the angle that the center line of the work roll forms with the center line of the mill is zero; and 
     FIG. 4 is a schematic representation of the rolls of the prior art cross-rolling mill of FIG. 3, showing the arrangement of the rolls. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 2 and 3, there is shown a rolling mill embodying the concept of the present invention. This mill has a housing 1 on the work side, a second housing 2 on the driver side, a project block 3, a hydraulic cylinder plunger 4 for crossing operation, a hydraulic cylinder cover 5, a roll chock 6 on the work side, a work roll 7, a second project block 8, a second hydraulic cylinder plunger 9 for crossing operation, a second hydraulic cylinder cover 10, a lever 11, a link 12, a thrust pad 13, a clamp plate 14, a chock clamp body 15, a roll chock 16 on the driver side, a chock liner or flat liner 17, a housing liner or cylindrical liner 18, a project block 19, a spindle 20, radial bearings 21 on the work side, thrust bearings 22, radial bearings 23 on the driver side, further hydraulic cylinder plungers 24 and 25 for crossing operation, and hydraulic cylinders 26 for roll bending. 
     Referring specifically to FIG. 2, the upper roll 7 is held by a work roll-chock assembly mounted on the work side. This assembly comprises the work roll chock 6, the chock liner 17, the lever 11, the link 12, and the thrust pad 13. The work roll chock 6 incorporates the radial bearings 21 and the thrust bearings 22. The thrust pad 13 incorporates spherical bearings or spherical roller bearings (not shown), and cooperates with the lever 11 and the link 12 to constitute a thrust bearing mechanism that follows the crossing operation of the rolls. 
     The chock clamp body 15 is rigidly fixed to the side of the housing 1. The thrust bearing 13 is held between the clamp body 15 and the clamp plate 14, so that the bearing can be shifted back and forth to axially place the work roll in position. The project blocks 3 and 8 are rigidly attached to the inner surface of the opening formed in the housing 1. The block 3 incorporates the cylinder plunger 4, the cylinder cover 5, and the corresponding hydraulic cylinder 26 for roll bending. Similarly, the block 8 incorporates the cylinder plunger 9, the cylinder cover 10, and the corresponding cylinder 26. 
     The project block 19 is firmly mounted to the housing 2 on the driver side. This block 19 is equipped with no crossing cylinders, but incorporates only the cylinder for roll bending. The block 19 is connected to the chock liner 17 via the cylindrical liner 18. The work roll chock 16 on the driver side incorporates the radial bearings 23. The work roll 7 is rotated by the mill spindle 20. The lower roll has the crossing cylinders 24 and 25 disposed on the driver side in an opposite relation to those disposed on the upper roll. No crossing cylinders are provided on the work side. The roll chock and the project block are connected together via the flat liner and the cylindrical liner. 
     In the rolling mill constructed as described above, the upper roll crossing cylinders 4 and 9 on the work side are moved toward the exit end of the mill, and the lower roll crossing cylinders 24 and 25 are moved toward the exit end of the mill to produce the condition shown in FIG. 1, where the axes of the rolls cross each other when viewed in plan. This operation is enabled by the fact that the chock liner 17 on the driver side of the upper roll is a flat liner and that the housing liner 18 on the work side of the lower roll is a cylindrical liner. This crossing operation prevents the intersection point from moving awa from the center line. Therefore, the roll gap can be varied in a symmetrical relation with respect to the center line, according to the angle at which the axes of the rolls cross. Hence, the shape of the rolled material can be controlled according to the conditions of rolling. 
     In the present example, the rolls are moved in such a way that their axes cross each other by the actuation of hydraulic cylinders. The invention can also have a system, as shown in FIG. 2(c) where the axes of the rolls are made to cross each other on one side by electric motors. Also in the above example, the crossing cylinders are mounted on the work side of the upper roll and on the driver side of the lower roll, respectively. It is also possible to mount the crossing cylinders on the driver side of the upper roll and on the work side of the lower roll. 
     The novel rolling mill is simple in structure, requires less maintenance, and easily accommodates the foundation and other devices, such as a roll exchange device.