Abstract: Apparatus for forming tapered spiral tubes from strips, is disclosed. The apparatus comprises a spiral tube forming system for forming a strip into a spiral tube; a strip infeed system adapted for feeding a strip to the pipe forming system; and computer-controlled means for continuously varying the angular orientation of the tube forming system relative to the strip infeed system to selectively vary the diameter of the forming tube. The selective variation of the diameter includes linearly tapered and curved profiles, as well as constant (unchanging) diameter profiles and combinations thereof.

Abstract: A coupling and methods for interconnecting the ends of spirally ribbed pipe are disclosed. Grooves are formed transversely across two or more ribs of the pipe and a coupling ring is secured to the end of the pipe by lugs or cleats which rotatably engage with the grooves. Contact surfaces of the lugs are angled relative to the grooves to center the coupling ring axially of the pipe. The angular relationship of the grooves and contact surfaces of the lugs draw the ring into abutting contact with the end of the pipe as they rotatably engage the grooves.

Abstract: A roll forming process is described wherein longitudinal areas of curvature are formed in strip material between longitudinal areas of narrower width, the areas of curvature being bowed downwardly from the center toward the longitudinal flat areas. As the strip material is fed progressively through roll forming stations, the longitudinal areas of curvature are formed into areas of lesser curvature and finally flattened to provide strip material having relative flat areas separated by substantially rectangular ribs. The process is one in which areas of curvature are provided to initially gather strip material for use in forming the sides of one or more ribs with little or no thinning of the strip material.

Abstract: A method is described for manufacturing helically formed pipe from strip material. One side of the strip material is formed to provide a first side flange that projects substantially 90.degree. relative to the plane of the strip. The opposite side of the strip is formed with a channel that includes a second side flange that also projects substantially 90.degree. relative to the plane of the strip but in the opposite direction from the first side flange. The strip material is then helically coiled while the first and second side flanges are moved into abutting contact. Pressure is then applied radially of the pipe axis, forcing the contacting edges of the flanges together while the flanges are welded, thus forming a rib with a helical weld seam located at or near the line of neutral forces in the rib.

Abstract: A travelling pipe cut-off is described having a pair of knife-edged rollers mounted on a carriage that also supports a cut-off torch. At least one roller is engaged with the smooth surface of the pipe at all times during cut-off, each such roller advancing the carriage while the pipe is being advanced. The two rollers are spaced apart such that, as the bulge of a pipe seam approaches one of the rollers, that roller is moved out of engagement with the pipe, but the other roller remains in engagement. The carriage and cut-off mechanism is, therefore, advanced only by that roller which is engaged with a smooth surface of the pipe.

Abstract: A spiral ribbed pipe formed from an elongate strip coiled helically. The pipe has a helical seam and an integral reinforcing rib formed along and around the seam, thereby increasing strength and rigidity of the pipe and its seam. The helical seam comprises a pair of interlocking edges located radially inward of the rib and intermediate a pair of offsets, whereby the inner surface of each coil of strip is longitudinally aligned with the surfaces of adjacent coils to provide a smooth interior pipe surface.

Abstract: Method for removing camber from strip preparatory to forming helical pipe is taught utilizing the steps of feeding the strip longitudinally along a directional line of feed, sensing lateral deviations of the strip relative to the directional line of feed, laterally moving and realigning the strip in response to lateral deviations, then severing both side edges of the strip on lines parallel with the directional line of feed.

Abstract: Method and apparatus for removing camber from strip preparatory to forming helical pipe is taught utilizing the steps of feeding the strip longitudinally along a directional line of feed, sensing lateral deviations of the strip relative to the directional line of feed, laterally moving and realigning the strip in response to lateral deviations, then severing both side edges of the strip on lines parallel with the directional line of feed.Apparatus for practicing the method comprises a pair of laterally spaced guide rolls which are mounted for lateral adjustment toward and away from the other, means for moving the guide rolls simultaneously as a unit as well as independently of each other, and control means, including servomechanisms for positioning each roll in response to variations in both width of the strip and camber.

Abstract: Double wall helical pipe formed from a single metal strip, pipe forming method and configuration of strip for forming such pipe. A metal strip is formed with pipe seam elements and curled into overlapped helical convolutions, and the seam elements are secured together to provide a helical pipe seam. One or both pipe walls may be corrugated.

Abstract: The present invention relates to machines for recorrugating the ends of a helically corrugated pipe. One end of the pipe is inserted between and engaged by a juxtaposed pair of recorrugating rollers. The rollers are mounted on shafts which are driven to recorrugate the end of the pipe. As an improvement in such machines, the present invention provides a rotatable annular thrust ring, the marginal portion of which passes between the shafts. At least a portion of the end of the pipe to be recorrugated is abutted against the thrust ring to prevent axial movement of the pipe as it is being recorrugated. The ring is allowed to rotate during the recorrugating process to minimize damage to the end of the pipe.