Machine for producing spiral seamed pipe

Abstract

A machine for producing spiral seamed hollow pipe having a central axis from a metal strip having a first side which becomes the inside surface of the spiral pipe, a second side which becomes the outside surface of the spiral pipe, a width, and two outer edges. The machine includes a being roller station wherein the metal strip is formed into a helix using rolling contact. As the strip is driven through the bending roller station the strip is continuously bent on a bending line which is parallel to the central axis of the spiral pipe and which extends across the metal strip at an angle offset from a right angle with reference to the outer edges of the strip. Within the bending roller station there are a plurality of rollers organized as what may be viewed as staggered roller segments extending across the strip along the bending line which is offset from a right angle. At the same time, the rotational axes of the rollers are perpendicular to the strip.

What is claimed is:  
     
         1 . A machine for producing spiral seamed hollow pipe having a central axis from a metal strip having a first side which is to become the inside surface of the spiral pipe, a second side which is to become the outside surface of the spiral pipe, two outer edges, and a width, said machine comprising: 
 a bending roller station including a plurality of bending roller sets through which the metal strip is driven for continuously bending the metal strip on a bending line parallel to the central axis of the spiral pipe being produced and extending generally across the metal strip but at an angle offset from a right angle with reference to the outer edges of the metal strip as the metal strip enters said bending roller station, the offset angle being determined based on the width of the strip and the diameter of spiral pipe produced, said bending roller sets being positioned generally side-by-side generally in respective roller set planes which are parallel to each other and to the outer edges of the metal strip and perpendicular to the metal strip as the metal strip enters said bending roller station;    each of said bending roller sets including an inside roller, an outside upstream roller cooperating with said inside roller to define a pinch roller pair, and an outside downstream roller, each of said rollers having a respective rotational axis perpendicular to the outer edges of the metal strip as the metal strip enters the bending roller station and an axial midplane perpendicular to the rotational axis, the axial midplanes of said rollers lying generally within the respective roller set plane; and    within each of said bending roller sets, said inside roller contacting the first side of the metal strip along the bending line, said outside upstream roller contacting the second side of the metal strip along the bending line, and said outside downstream roller contacting the second side of the metal strip downstream of the bending line and positioned so as to cause the strip to bend at the bending line for forming the metal strip into a spiral cylinder with the outer edges of the strip adjacent each other.    
     
     
         2 . The machine of  claim 1 , which further comprises: 
 a set of flange forming rollers upstream of said bending roller station for forming the outer edges of the metal strip into mating profiles suitable for forming a lockseam; and wherein    within an interior end one of said roller sets, said inside roller and said outside roller define a seam roller pair to compress adjacent outer edges of the strip to form the lockseam.    
     
     
         3 . The machine of  claim 2 , which further comprises a pipe cutting apparatus including: 
 a cutter support boom extending generally parallel to the pipe central axis past said bending roller station into the spiral pipe being produced;    said cutter support boom including a free end portion which, when cutting is to take place, moves at the same rate and in the same direction as spiral pipe being produced advances so that the free end portion remains in the same axial position with reference to the spiral pipe being produced; a cutting device carried by said free end portion; and    a cutting device carried by said free end portion.    
     
     
         4 . The machine of  claim 3 , wherein said cutting device comprises a plasma cutting torch directed towards the inside surface of the spiral pipe.  
     
     
         5 . The machine of  claim 4 , which further comprises an exhaust gas collector located adjacent the outside surface of the spiral pipe opposite said plasma cutting torch.  
     
     
         6 . The machine of  claim 1 , which further comprises a plasma cutting torch for cutting off a length of spiral seamed pipe as it is produced by said machine.  
     
     
         7 . The machine of  claim 1 , which further comprises: 
 a stationary machine base;    a pivotable base pivotably attached to said stationary machine base for pivoting on a pivot axis perpendicular to and intersecting the spiral pipe central axis and intersecting the bending line generally at a point where outer edges of the metal strip are adjacent each other, the position of said pivotable base being adjusted based on the width of the strip and the diameter of spiral pipe produced; and    said bending roller station being mounted to said pivotable base.    
     
     
         8 . The machine of  claim 2 , which further comprises: 
 a stationary machine base;    a pivotable base pivotably attached to said stationary machine base for pivoting on a pivot axis perpendicular to and intersecting the spiral pipe central axis and intersecting the bending line where said seam roller pair compresses adjacent outer edges of the strip, the position of said pivotable base being adjusted based on the width of the strip and the diameter of spiral pipe being produced; and    said set of flange forming rollers and said bending roller station being mounted to said pivotable base.    
     
     
         9 . The machine of  claim 1 , wherein said inside rollers, outside upstream rollers and outside downstream rollers of said bending roller sets have respective individual roller supports, the positions of which are controlled by servomechanisms for adjustment to produce spiral pipe in different diameters.  
     
     
         10 . The machine of  claim 9 , wherein the positions of said roller supports are adjustable on-the-fly to produce spiral seamed pipe flat oval in cross section.  
     
     
         11 . The machine of  claim 9 , wherein the positions of said roller supports and the position of said pivotable base are adjustable on-the-fly to produce a spiral seamed transition section which varies in diameter along its length.  
     
     
         12 . A machine for producing spiral seamed hollow pipe from a metal strip, comprising: 
 a bending device which forms the strip into a spiral cylinder so that the outer edges are adjacent to each other, and a lockseam roller for joining the adjacent edges to produce a spiral seamed pipe which rotates and advances in an axial direction as it is produced; and    a plasma cutting torch which is energized when a length of spiral seamed pipe is to be cut off, said plasma cutting torch, when cutting is to take place, moving at the same rate and in the same direction as spiral pipe being produced advances so that said plasma cutting torch remains in the same axial position with reference to the spiral pipe being produced.