Mold for casting elongated hollow objects

Claim 1

A CONTRACTIBLE TUBULAR CORE WHICH COMPRISES: (A) AN OUTER CYLINDRICAL SHELL HAVING A LONGITUDINAL SEAM FORMED BY RESPECTIVELY OVERLAPPING AND UNDERLAPPING CIRCUMFERENTIALLY EXTENDED MARGINAL PARTS OF THE SHELL, (B) FIRST MEANS INCLUDING AN ACTUATING ROD DISPOSED AXIALLY WITHIN THE SHELL AND A FIRST PLURALITY OF LINKS DISTRIBUTED LONGITUDINALLY AND PIVOTALLY CONNECTED TO SAID ROD AND SHELL FOR CONTRACTING AND EXPANDING SAID SHELL INCLUDING ONLY SAID UNDERLAPPING PART THEREOF BUT EXCLUDING SAID OVERLAPPING PART THEREOF BY MOVEMENT OF SAID ROD, AND (C) SECOND MEANS OPERABLE INDEPENDENTLY OF SAID FIRST MEANS FOR CONTRACTING SAID OVERLAPPING PART BOTH AFTER CONTRACTION AND AFTER EXPANSION OF SAID UNDERLAPPING PART AND FOR EXPANDING SAID OVERLAPPING PART, SAID SECOND MEANS COMPRISING A SECOND PLURALITY OF LINKS PIVOTALLY CONNECTED TO THE SHELL NEAR SAID OVERLAPPING MARGINAL PART AND MOUNTED IN PUSHING AND PULLING RELATION TO A PART OF THE SHELL WHICH IS SUBSTANTIALLY OPPOSITE TO SAID OVERLAPPING PART.