Abstract: In an embodiment, a long reinforcing material-attached profile strip (100) in which joint portions are formed at both side edge portions and to which a reinforcing material continuously formed in the longitudinal direction is attached is supplied, and mutually adjacent joint portions are joined to each other, thereby producing a spiral pipe (S). A curl-forming apparatus (3) includes a sending roller for the reinforcing material-attached profile strip (100) and a curl guide. Using the curl-forming apparatus (3), adjacent parts of the reinforcing material-attached profile strip (100) are subjected to plastic deformation to form spirals by being provided with arc-like curls having a radius of curvature substantially similar to or not greater than the radius of curvature of the spiral pipe (S). Accordingly, the spiral pipe (S) can be produced while suppressing the action of a restoring force that restores the reinforcing material-attached profile strip (100) to its original radius of curvature.

Abstract: In an embodiment, a long reinforcing material-attached profile strip (100) in which joint portions are formed at both side edge portions and to which a reinforcing material continuously formed in the longitudinal direction is attached is supplied, and mutually adjacent joint portions are joined to each other, thereby producing a spiral pipe (S). A curl-forming apparatus (3) includes a sending roller for the reinforcing material-attached profile strip (100) and a curl guide. Using the curl-forming apparatus (3), adjacent parts of the reinforcing material-attached profile strip (100) are subjected to plastic deformation to form spirals by being provided with arc-like curls having a radius of curvature substantially similar to or not greater than the radius of curvature of the spiral pipe (S). Accordingly, the spiral pipe (S) can be produced while suppressing the action of a restoring force that restores the reinforcing material-attached profile strip (100) to its original radius of curvature.

Abstract: In an embodiment, a long reinforcing material-attached profile strip (100) in which joint portions are formed at both side edge portions and to which a reinforcing material continuously formed in the longitudinal direction is attached is supplied, and mutually adjacent joint portions are joined to each other, thereby producing a spiral pipe (S). A curl-forming apparatus (3) includes a sending roller for the reinforcing material-attached profile strip (100) and a curl guide. Using the curl-forming apparatus (3), adjacent parts of the reinforcing material-attached profile strip (100) are subjected to plastic deformation to form spirals by being provided with arc-like curls having a radius of curvature substantially similar to or not greater than the radius of curvature of the spiral pipe (S). Accordingly, the spiral pipe (S) can be produced while suppressing the action of a restoring force that restores the reinforcing material-attached profile strip (100) to its original radius of curvature.

Abstract: In an embodiment, a long reinforcing material-attached profile strip (100) in which joint portions are formed at both side edge portions and to which a reinforcing material continuously formed in the longitudinal direction is attached is supplied, and mutually adjacent joint portions are joined to each other, thereby producing a spiral pipe (S). A curl-forming apparatus (3) includes a sending roller for the reinforcing material-attached profile strip (100) and a curl guide. Using the curl-forming apparatus (3), adjacent parts of the reinforcing material-attached profile strip (100) are subjected to plastic deformation to form spirals by being provided with arc-like curls having a radius of curvature substantially similar to or not greater than the radius of curvature of the spiral pipe (S). Accordingly, the spiral pipe (S) can be produced while suppressing the action of a restoring force that restores the reinforcing material-attached profile strip (100) to its original radius of curvature.