Patent ID: 8672666

Claim:
Apparatus for making a tubular body, comprising a base, an outer mold for receiving a flowable material and having an open mold end closed off by the base, and an inner collapsible mold that is initially attached on a plunger piston for movement therewith into the outer mold and later detachable from the plunger piston, said inner collapsible mold having a smaller transverse dimension than the outer mold to define a space therebetween, said inner collapsible mold having an overlapping region along a longitudinal slit therein, said inner collapsible mold initially attached on the plunger piston and said outer mold being relatively movable to move the inner collapsible mold initially attached on the plunger piston into the flowable material residing in the outer mold with an end of the plunger piston engaging and moving the flowable material into the space between the outer mold and inner collapsible mold where it can form a tubular body and to eventually contact the plunger piston with the base to form an open end of the tubular body, said inner collapsible mold being detachable from the plunger piston after the tubular body is formed so as to remain in the tubular body and thereafter collapsible in transverse dimension to accommodate shrinkage of the tubular body to avoid cracking of the tubular body.