Apparatus for manufacturing wrinkled pipes

A wrinkled pipe manufacturing apparatus in which an elastic member is inserted into a pipe to be worked and is pushed from at least one side so that it may be radially bulged to form an annular bulge on the circumference of said pipe and in which a punch and a chuck disposed around the circumference of said pipe are axially moved relative to each other to form an annular wrinkle from said annular bulge, the annular wrinkle defining an external diameter and an axial length, wherein the improvement comprising:

• first and second mandrels held over a bed to move freely in axial directions along an upper face of said bed, said mandrels having outer circumferences dimensioned to be inserted into the pipe for supporting the pipe;
• first drive means for driving said mandrels in said axial directions;
• an elastic member arranged in said pipe and between opposed leading end faces of said first and second mandrels;
• second drive means for moving at least one of the punch and the chuck toward one another;
• and
• a chuck guide sleeve and a punch guide sleeve projecting axially toward one another from the chuck and the punch respectively, the punch guide sleeve defining an internal diameter substantially equal to the external diameter of the annular wrinkle to be formed and defining an axial length substantially equal to the axial length of the annular wrinkle to be formed for controlling said external diameter and axial length of each wrinkle to be formed, the punch guide sleeve further having an external surface defining an external diameter, the chuck guide sleeve having an internal surface defining an internal diameter substantially equal to the external diameter of the punch guide sleeve, the internal surface of the chuck guide sleeve and the external surface of the punch guide sleeve being in abutting sliding relationship with one another for accurately guiding said chuck and said punch in said axial directions.