PURPOSE: To make it possible to pull out the title mold easily and surely by piercing a heated and softened resin-made inner mold with two or more rods, expanding and contracting the diameter around the center of the pipe axis, rotating the rods around the center of the pipe axis, winding the inner mold around the rods and pulling the inner mold out in the pipe axis direction.
CONSTITUTION: A piston 41 of an expanding and contracting cylinder apparatus 4 is contracted and piercing rods 3 are made under a parallel condition. A mold release apparatus 1 is set in such a way that the axial direction of an inner mold 8 coincides with the axial direction of a rotating axis 2. Then, the piston is extended to pierce the inner mold 8 with the piercing rods 3. Then, the piston part 52 of the expanding and contracting cylinder apparatus 5 is contracted to expand the diameter of a circle formed by the piercing rods 3 around the axial center of the inner mold 8. The rotating axis is rotated by rotating a motor 6 through a gear 63, a gear 61 and a spline part 20.
ISHIYASU TOSHIYUKI
OKOSE TATSUO
OKAYAMA SEKISUI KOGYO KK