Patent ID: 8277716

Claim:
An apparatus for manufacturing a composite tubular, comprising: a filament winding machine a mandrel around which a filament is adapted to be wound, the mandrel having a chamber within, the mandrel being mounted on the filament winding machine for being rotatably driven by the filament winding machine, the mandrel further comprising: an outer cylindrical shell having a first end that is closed and a second end; an inner cylinder having a piston portion adjacent the first end and a shaft portion extending from the piston portion into abutment with an internal shoulder adjacent to the second end of the outer cylindrical shell, the piston portion having a seal between its outer diameter and the outer cylindrical shell, defining the chamber between the piston portion and the first end of the outer cylindrical shell; and a port located on the mandrel and in communication with the chamber, the port being connectable to a pressure source to allow pressurization of the chamber in order to create a compressive force on the inner cylinder and thereby stiffen the mandrel.