Apparatus for Working Tubes, Bars, Sections and Similar Blanks, Comprising a Plurality of Machines Arranged in Line

Abstract

The apparatus includes a plurality of machines ( 10, 12, 14 ) arranged in line along a longitudinal direction (x) coinciding with a feed direction of the blank (C). Each machine ( 10, 12, 14 ) is provided with rollers ( 18, 20, 22 ) arranged to be driven into rotation by respective motors to work simultaneously on the blank (C) and with a control unit arranged to control these motors. Each machine ( 10, 12, 14 ) is provided with a measuring device ( 24 ) adapted to provide the control unit of that machine with a measure of the overall reaction exerted by the blank (C) under working on the rollers ( 18, 20, 22 ) of that machine along the longitudinal direction (x). The control unit of each machine ( 10, 12, 14 ) is arranged to torque-control the rollers ( 18, 20, 22 ) of that machine in such a manner that the overall reaction exerted by the blank (C) under working on the rollers ( 18, 20, 22 ) of that machine along the longitudinal direction (x) is equal to a predetermined value, zero included.

What is claimed is: 
     
         1 . An apparatus for working elongated blanks (C), such as tubes, bars, sections and strips, comprising a plurality of machines ( 10 ,  12 ,  14 ) arranged in line along a longitudinal direction (x) coinciding with a feed direction of the blank (C),
 each of said machines ( 10 ,  12 ,  14 ) comprising at least one working member ( 18 ,  20 ,  22 ), which is rotatably mounted about an axis of rotation (z 1 , z 2 , z 3 ) and is adapted to work on the blank (C) so as to apply on it a force having a component directed along the longitudinal direction (x), a driving unit for driving said at least one working member ( 18 ,  20 ,  22 ) into rotation, and a control unit for controlling said driving unit,   wherein each machine ( 10 ,  12 ,  14 ) is provided with a measuring device ( 24 ) for providing the control unit of said machine with a measure of an overall reaction force exerted in operation by the blank (C) on said machine along the longitudinal direction (x), and   wherein the control unit of each machine ( 10 ,  12 ,  14 ) is arranged to control said driving unit in such a manner that the value, provided by said measuring means, of the overall reaction force exerted in operation by the blank (C) on said machine along the longitudinal direction (x) is equal to a predetermined value, zero included.   
     
     
         2 . The apparatus of  claim 1 , wherein at least one of said machines ( 10 ,  12 ,  14 ) is mounted on a respective support structure ( 26 ) with a translational degree of freedom in the longitudinal direction (x) and wherein the measuring device ( 24 ) of said at least one machine ( 10 ,  12 ,  14 ) is interposed between the machine ( 10 ,  12 ,  14 ) and the support structure ( 26 ). 
     
     
         3 . The apparatus of  claim 2 , wherein said at least one machine ( 10 ,  12 ,  14 ) is mounted on the respective support structure ( 26 ) by means of linear guides ( 28 ). 
     
     
         4 . The according of  claim 2 , wherein said measuring device ( 24 ) comprises a load cell connected on one side to said at least one machine ( 10 ,  12 ,  14 ) and on the other to the respective support structure ( 26 ). 
     
     
         5 . The apparatus of  claim 1 , wherein said driving unit comprise, for each working member ( 18 ,  20 ,  22 ), a respective motor. 
     
     
         6 . The apparatus of  claim 5 , wherein the control unit of each machine ( 10 ,  12 ,  14 ) is arranged to torque-control each motor of said machine. 
     
     
         7 . The apparatus of  claim 6 , wherein the control unit of at least one of said machines ( 10 ,  12 ,  14 ) is arranged to define the torques to be applied by the motors of said machine on the basis of a predefined proportionality criterion. 
     
     
         8 . The apparatus of  claim 6 , wherein at least one of said machines ( 10 ,  12 ,  14 ) comprises an additional measuring device for measuring the normal force exerted between the blank and each working member ( 18 ,  20 ,  22 ) and wherein the control unit of said at least one machine ( 10 ,  12 ,  14 ) is arranged to define the torques to be applied by the motors of said machine on the basis of the force measures provided by said additional measuring device. 
     
     
         9 . The according of  claim 3 , wherein said measuring device ( 24 ) comprises a load cell connected on one side to said at least one machine ( 10 ,  12 ,  14 ) and on the other to the respective support structure ( 26 ).