Patent ID: 7846377

Claim:
A method of processing a fully formed synthetic resin tube, which comprises: inserting a mandrel into the fully formed synthetic resin tube while bringing an inner wall of the fully formed synthetic resin tube into contact with the mandrel, wherein the mandrel is a bottomed cylindrical mandrel that is closed at one end, the mandrel having a first mold portion and a second mold portion, wherein the second mold portion has a shape formed in a non-circumferential part of an outer surface of the mandrel, which does not extend around an entire circumference of the mandrel, the shape being selected from a hollowed shape, a raised shape, and a hollowed and raised shape that is different than a shape of the first mold portion, the second mold portion having small through-holes for applying force; heating and softening an area of the fully formed synthetic resin tube in and around an area facing the second mold portion after inserting the mandrel into the fully formed synthetic resin tube; allowing a peripheral portion of the heated and softened area to surround an entire edge of the second mold portion and to come into tight contact therewith, as caused by thermal shrinkage involved in the heating and softening the area of the fully formed synthetic resin tube; after coming into tight contact with the second mold portion by the thermal shrinkage, deaerating the fully formed synthetic resin tube via a central opening and the small through-holes of the second mold portion to mold the heated and softened area of the fully formed synthetic resin tube by vacuuming air in the fully formed synthetic resin tube; and forming in the heated and softened area of the fully formed synthetic resin tube at least one portion selected from a hollowed portion, a raised portion, and a hollowed and raised portion.