Patent ID: 9248485
Filing Date: 2016-02-02
CPC Classification: B21C,B29C,B29D,B29L,F16L

Claim Text:
1. A method for producing a spiral pipe, comprising: disposing the pipe-producing machine in a manhole; separately disposing a curl-forming apparatus on an upstream side of the pipe-producing machine, the curl-forming apparatus including: an arc-like plate so as to configure a part of a spiral; and a support base; placing the support base on a ground near the manhole or on a bottom portion inside the manhole; placing a reinforcing material-attached profile strip in which joint portions are formed at both side edge portions and to which a reinforcing material continuously formed in a longitudinal direction is attached, along a concave surface of the arc-like plate; pushing or taking the reinforcing material-attached profile strip, providing arc-like curls having a radius of curvature substantially similar to or not greater than a radius of curvature of a spiral pipe, and subjecting the reinforcing material-attached profile strip to plastic deformation to form a spiral; joining the joint portions of adjacent parts of the reinforcing material-attached profile strip, using the pipe-producing machine having a joining mechanism, thereby producing a spiral pipe; and revolving the pipe-producing machine about an axis of the spiral pipe in the manhole, and drawing or pressing the spiral pipe in a state where the spiral pipe is not removed from the pipe-producing machine, and thereby inserting the spiral pipe into an existing pipe without being wound, wherein the pipe-producing machine never proceeds into the existing pipe.