Patent Publication Number: US-6209377-B1

Title: Housingless roll stand

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to rolling mills, and is concerned in particular with an improvement in the design of so-called “housingless” roll stands. 
     2. Description of the Prior Art 
     In the conventional housingless roll stand, the roll necks of the two work rolls are journalled in bearings contained in pairs of clocks located on opposite sides of the mill center line. The chocks of each pair are interconnected by two screw posts. The four screw posts (two on each side of the mill center line) absorb the roll separating forces during rolling. 
     The screw posts have opposite hand threaded portions engageable with nuts carried by the chocks. Symmetrical roll parting adjustments are effected by simultaneously rotating all four screw posts. 
     There are several drawbacks associated with this type of arrangement. For example, insertion and removal of the work rolls and their respective chocks entails painstaking and precise alignment of coacting components, requiring the use of expensive specially designed robotic equipment. 
     Moreover, the multiple pairs of screw posts and the gear drives required to effect their simultaneous rotation adds significantly to the initial price of each roll stand. 
     Accordingly, a primary objective of the present invention is the provision of a housingless roll stand which has a simplified compact design, in which only two screw posts are required to effect symmetrical roll parting adjustments. 
     A companion objective of the present invention is to simplify the task of removing and inserting the work rolls, chocks and associated adjustment mechanisms, thus making it unnecessary to resort to the use of specially designed and expensive robotic equipment. 
     SUMMARY OF THE INVENTION 
     A roll stand in accordance with the present invention includes a support structure adapted to be fixed at a selected location along the mill center line. First and second work rolls are configured and arranged to roll products directed therebetween. The first work roll has its roll necks journalled for rotation in bearings contained in first chocks, and the second work roll has its roll necks likewise journalled for rotation in bearings contained in second chocks, with the first and second chocks being arranged in pairs on opposite sides of the mill center line. 
     The first and second chocks of each roll pair are connected to the support structure for pivotal movement respectively about parallel first and second connecting axes which extend in parallel relationship with respect to the roll axes and orthogonally with respect to the mill center line. An adjustment mechanism simultaneously pivots the first and second chocks of each pair in opposite directions about their respective connecting axes in order to symmetrically adjust roll parting. 
     Preferably, the adjustment mechanism comprises nut members carried by the first and second chocks of each pair, a pair of threaded posts, one post being associated with each chock pair and having opposite hand threaded portions engageable with the chock nuts, and a remotely operable gear drive for mechanically coupling and simultaneously rotating both threaded posts. 
     Advantageously, the rotational axes of the rolls lie in a first plane, the chock connecting axes lie in a second plane parallel to and on one side of the first plane, and the threaded posts are contained in a third plane also parallel to the first plane and on a side thereof opposite to that occupied the second reference plane. 
     Preferably, the support structure includes a pair of link members separably connected to a base, with the first and second chocks of each pair being interconnected by and pivotally connected to one of the link members, and with the rolls, chocks, link members and mechanically interconnected threaded posts being separable as an integral assembly from the base. 
     These and other objects, features and advantages of the present invention will now be described in greater detail with reference to the accompanying drawings, wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a horizontal housingless roll stand in accordance with the present invention; 
     FIG. 2 is a top plan view of the roll stand shown in FIG. 1; 
     FIG. 3 is a sectional view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a sectional view taken along line  4 — 4  of FIG. 1; 
     FIG. 5 is an enlarged view of a connecting link and its associated prestressing elements; and 
     FIG. 6 is a view similar to FIG. 1 showing the roll stand in a disassembled state. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     With reference initially to FIGS. 1-3, a horizontal housingless roll stand in accordance with the present invention is generally depicted at  10 . The roll stand includes a support structure generally indicated at  12  adapted to be fixed at a selected location along the mill center line “CL”. The support structure has a base comprising a rectangular platform with side members  14   a ,  14   b  interconnected by end members  16   a ,  16   b  and upstanding walls  18   a ,  18   b . A pair of T-shaped caps  20  are fixed to the upper edge of wall  18   a . The caps are slotted as at  21 . 
     Disposed oppositely to the caps  20  are links  24  slotted as at  26 , with laterally extending arms  27  removably attached to the upper edge of wall  18   b  by means of swing bolts  28 . 
     First and second work rolls  30   a ,  30   b  are located between the support structure walls  18   a ,  18   b . The work rolls are configured and arranged to roll products (not shown) directed therebetween along the mill center line CL. The first roll  30   a  has its roll necks  32   a  journalled for rotation in bearings  34   a  contained in first chocks  36   a , and the second roll  30   b  likewise has its roll neck  32   b  journalled in bearings  34   b  contained in second chocks  36   b . It will be seen from FIG. 3 that the first and second chocks  36   a ,  36   b  are arranged in pairs on opposite sides of the mill center line CL. 
     The chocks  36   a ,  36   b  have laterally extending flanges  38  received in the slots  26  of the links  24 . Robust pins  40  extend through aligned openings in the chock flanges  38  and links  24  to connect the chocks  36   a ,  36   b  to the support structure  12  for pivotal movement about parallel connecting axes A 2  which extend in parallel relationship with respect to the rotational axes A 1  of the work rolls  30   a ,  30   b  and orthogonally with respect to the mill center line CL. 
     As can best be seen in FIG. 5, the links  24  additionally carry rotatable bell cranks  42  having first lever arms  42   a  engageable with contact pads  44  on the chock flanges  38 , and second lever arms  42   b  acted upon by spring loaded plungers  46 . The plungers  46  act through the bell cranks  42  to resiliently spread the chock flanges  38  and thus take up any clearances existing between them and the links  24  and pins  40 . 
     The opposite sides of the chocks  36   a ,  36   b  are grooved and notched to define laterally spaced cheeks  48  between which are located nuts  50  and captured by caps  52 . The nuts  50  have trunnions  54  which project laterally through openings defined by semicircular notches in the cheeks  48  and caps  52 . 
     A pair of screw posts  56  is provided, one on each side of the mill center line CL to service a respective pair of chocks  36   a ,  36   b . As can best be seen in FIG. 4, each screw post has opposite hand threaded portions  58   a ,  58   b  engaged respectively with one of the nuts  50  carried by each chock of a given pair. The lower ends of the screw posts are supported on the base platform by pillow blocks  60  and are provided at their upper ends with gears  62 . 
     It will be seen from FIG. 1 that the axes A 1  of the work rolls lie in a first reference plane P 1 . The connecting axes A 2  lie in a second reference plane P 2  on one side of reference plane A 1 , and the screw posts  56  lie in a third reference plane P 3  on the side of plane P 1  opposite to that occupied by reference plane P 2 . 
     The gears  62  are engaged by worms  64  carried on a cross spindle  66  driven by a motor  68 . The motor  68  is remotely operable to simultaneously rotate the screw posts  56 , which in turn act through the chock nuts  50  to simultaneously pivot the chocks  36   a ,  36   b  of each pair in opposite direction to thereby symmetrically adjust the parting between the rolls  30   a ,  30   b.    
     Only two screw posts with minimal gearing are required to effect such adjustments. The first, second and third planes P 1 , P 2  and P 3  respectively containing the roll axes A 1 , connecting axes A 2  and screw posts  56  are tightly arranged with minimum spacing therebetween, thereby providing a compact assembly. 
     As shown in FIG. 6, by simply loosening and dislodging the swing bolts  28 , an integral assembly comprising the rolls  30   a ,  30   b , chocks  36   a ,  36   b , links  24  and screw posts  56  with associated coupling and drive components can be lifted away from the support structure  12  and quickly and easily replaced with a replacement assembly. This can be accomplished by conventional lifting equipment without having to utilize specially designed robotic tools. 
     The compact nature of the design and the pivotal interconnection of the chocks is highly resistant to deflection under rolling loads. 
     In light of the foregoing, it will now be appreciated by those skilled in the art that various structurally and functionally equivalent components may be substituted for those herein illustrated and described without departing from the spirit and scope of the invention as defined by the claims appended hereto. For example, other types of adjustment mechanisms including hydraulically actuated cylinders and the like may be employed to pivotally adjust the chocks. The roll stand may be of the horizontal type, as illustrated, or of the vertical type.