Multi-stand rolling mill for rod-shaped bodies comprising three motorized-rollers stands

Abstract

The present invention relates to a multi-stand rolling mill (1) for tubular bodies. The rolling mill comprises a first section (10) for rolling on mandrel defined by a first plurality of rolling stands (15′, 15, 15″) arranged in sequence along a rolling axis (100). According to the invention, the rolling mill also comprises a second rolling section without mandrel, arranged down-stream of said first section, which comprises a second plurality of stands (25′, 25, 26, 27, 26′, 27′) arranged in sequence along said rolling axis (100). Each stand (25′, 25, 26, 27, 26′, 27′) of said second section (20) comprises three rollers having rotation axes which are arranged at 120° from one another. The rotation axes for each stand (25′, 25, 26, 27, 26′, 27′) are rotated by 180° with respect to corresponding rotation axes of an adjacent stand. According to the invention, at least one stand of said second section (20) comprises a motorized roller having a vertical rotation axis.

1 . A rolling mill for tubular bodies comprising a first section for rolling on mandrel defined by a first plurality of rolling stands arranged in sequence along a rolling axis, characterized in that it comprises a second section for extracting said mandrel and calibrating the diameter of said tubular bodies, said second section being downstream of said first section, whereby said tubular bodies exiting from said first section directly enter said second section, said second section comprising a second plurality of rolling stands without mandrel, arranged in sequence along said rolling axis, wherein each stand of said second section comprises three rollers, the rotation axes of which are arranged at 120° relative to one another and wherein, for each stand, said rotation axes are rotated by 180° relative to corresponding rotation axes of an adjacent stand, said position of said rotation axes being assessed with respect to a vertical reference direction, and wherein at least one stand of said second section comprises a motorized roller having a vertical rotation axis. 
     
     
         2 . The rolling mill according to  claim 1 , wherein said second section comprises at least one fixed rollers stand. 
     
     
         3 . The rolling mill according to  claim 1 , wherein said second section comprises at least one adjustable rollers stand. 
     
     
         4 . The rolling mill according to  claim 1 , wherein said second section comprises a first series of fixed rollers stands arranged in sequence along said rolling axis starting from an inlet side of said second section, at least one of said fixed rollers stands comprising mechanical drive means configured to transmit the motion from said motorized roller having vertical rotation axis to the other rollers of the same stand. 
     
     
         5 . The rolling mill according to  claim 1 , wherein said second section comprises at least one dummy stand comprising at least one guide roller. 
     
     
         6 . The rolling mill according to  claim 1 , wherein each stand of said first section comprises three rollers, the rotation axes of which are arranged at 120° relative to one another and wherein the rotation axes of the rollers of an outlet stand of said first section are rotated by 180° with respect to the rotation axes of the rollers of an inlet stand of said second section. 
     
     
         7 . The rolling mill according to  claim 1 , wherein said second section comprises a first stretch which defines a first plurality of lodging positions each of which configured for accommodating a fixed rollers stand or a dummy stand, said second section comprising a second stretch, downstream of said first stretch, which defines a second plurality of lodging positions each of which configured for accommodating a fixed rollers stand or a dummy stand or an adjustable rollers stand. 
     
     
         8 . The rolling mill according to  claim 3 , wherein said second section comprises a group of adjustable rollers stands, said group comprising:
 a first stand and a second stand adjacent to said first stand, wherein said first stand comprises at least one roller motorized by an actuating means;   a transmission device which operatively connects said at least one roller of said first stand to at least one roller of said second stand so that both the rollers are actuated by said actuating means.   
     
     
         9 . The rolling mill according to  claim 7 , wherein said second section comprises a group of adjustable rollers stands, said group comprising:
 a first stand and a second stand adjacent to said first stand, wherein said first stand comprises at least one roller motorized by an actuating means;   a transmission device which operatively connects said at least one roller of said first stand to at least one roller of said second stand so that both the rollers are actuated by said actuating means, and   
       wherein said second stretch of said second section defines three lodging positions and wherein said group of adjustable rollers stands is configured to occupy the first lodging position and the second lodging position downstream of said first stretch. 
     
     
         10 . The rolling mill according to  claim 7 , wherein said second section comprises a group of adjustable rollers stands, said group comprising:
 a first stand and a second stand adjacent to said first stand, wherein said first stand comprises at least one roller motorized by an actuating means;   a transmission device which operatively connects said at least one roller of said first stand to at least one roller of said second stand so that both the rollers are actuated by said actuating means, and   
       wherein said second stretch of said second section defines three lodging positions and wherein said group of adjustable rollers stands is configured to occupy the second lodging position and the third lodging position downstream of said first stretch. 
     
     
         11 . The rolling mill according to  claim 8 , wherein said group comprises at least a first transmission device which operatively connects a first vertical axis roller of said first stand to a first vertical axis roller of said second stand. 
     
     
         12 . The rolling mill according to  claim 8 , wherein said first stand and said second stand of said group are integrated in a single body defining an operating recess inside which the rollers of said first stand and the rollers of said second stand are accommodated. 
     
     
         13 . The rolling mill according to  claim 8 , wherein said first stand and said second stand of said group each comprise:
 a first roller having a vertical rotation axis;   a second roller having a rotation axis inclined by 120° with respect to said vertical rotation axis of said first roller, said second roller being operatively positioned above a horizontal reference plane on which said rolling axis lies;   a third roller having a rotation axis inclined by 120° with respect to said rotation axes of said first roller and of said second roller, said third roller being operatively positioned below said horizontal reference plane, and wherein said group comprises a second transmission device which operatively connects said third roller of said first stand to said second roller of said second stand, said third roller of said first stand being actuated by an actuating means.   
     
     
         14 . The rolling mill according to  claim 13 , wherein said group comprises a further transmission device which operatively connects said second roller of said first stand to said third roller of said second stand, said third roller of said second stand being actuated by a further actuating means.