Flexible expansion joint

An extensible flexible joint wherein hollow spherical portions formed at ends of first and second opposed tubes are fitted to each other inside and outside so as to couple the first and second opposed tubes in a manner such that the first and second opposed tubes can be bent, said joint comprising:

• a packing in which two opposed recessed portions are formed, said packing being provided between an open end face of the hollow spherical portion fitted outside and an outside section of the hollow spherical portion fitted inside;
• at least one lip portion formed on each of the recessed portions;
• and
• a holding member coupled to the open end face of the hollow spherical portion fitted outside so as to hold the packing between the open end face of the hollow spherical portion fitted outside and the outside section of the hollow spherical portion fitted inside;
• wherein:
• at least one of the first and second opposed tubes comprises a holding seat provided at a tube end portion opposite the hollow spherical portion thereof;
• said holding seat is adapted to accommodate another packing having opposed recessed portions formed therein;
• said another packing is adapted to form a seal with an intermediate fitting tube to be fitted to said one of the first and second opposed tubes;
• said intermediate fitting tube comprises a stopper adapted to be engaged with the packing holding seat of said one of the first and second opposed tubes;
• and
• said stopper is held in place on said intermediate fitting tube by a removable fixing member, and said stopper is selected to have a length in accordance with a desired extensibility between said intermediate fitting tube and said one of the first and second opposed tubes to which said intermediate fitting tube is to be fitted.