Rigid segmented mandrel with inflatable support

A mandrel apparatus for forming a hollow shell having an interior chamber extending longitudinally along an axis, and first and second end regions adjacent to said axis at respective ends of said shell, said mandrel apparatus comprising:

• a plurality of elongated sector pieces having inner and outer faces and adapted when assembled in an edge-to-edge relationship to form a mandrel having a peripheral wall providing an exterior surface for forming at least a portion of said interior chamber of said shell;
• means cooperating with said peripheral wall for forming an opening into said interior chamber of said shell;
• and,
• bladder means inflatable within said peripheral wall by a pressurized fluid to apply pressure against said inner faces, said pressure maintaining said sector pieces in said edge-to-edge relationship when said bladder is in an inflated condition;
• each of said sector pieces comprising a longitudinally extending wall segment and first and second edge portions extending longitudinally along opposite edges of said wall segment, said edge portions being configured to interlockingly engage corresponding edge portions of adjacent sector pieces when said bladder is in said inflated condition to form connecting joints which retain said sector pieces in a substantially rigid predetermined configuration corresponding to said peripheral wall;
• and said connecting joints permitting said sector pieces to be separated when said bladder means is in a deflated condition, said opening being adapted to pass said separated sector pieces out from said interior chamber of said shell after the forming thereof.