Patent ID: 8347477

Claim:
A pipe producing apparatus for continuously feeding an elongated profile strip into an existing pipe, helically winding the profile strip, and joining adjacent windings of the profile strip to form a tubular structure, and further feeding a new winding of the profile strip to a front of the tubular structure, thereby progressively and additionally forming a tubular structure, wherein the apparatus comprises a shaping frame provided in the existing pipe, and a plurality of guide rollers rotatably supported by the shaping frame, the shaping frame includes a drive unit for forcedly feeding the profile strip from an inside of the shaping frame, and a bending link coupled with the shaping frame, wherein the bending link is bent toward an inside of the shaping frame, in the shaping frame, a plurality of linking bodies including a pair of linking elements rotatably coupled via coupling shafts, are coupled with the drive unit and the bending link such that the plurality of linking bodies, the drive unit and the bending link form a substantially enclosed annular shape, and the bending link includes an actuator for changing a bent shape of the bending link, wherein a length of a circumference of the shaping frame is expanded or contracted by increasing or decreasing a bent angle of the bending link, thereby applying tension to a previous winding of the profile strip via the guide roller.