Joint assembly for flexible and semi-rigid pipings

A joint assembly for flexible, semi-rigid or rigid pipings, comprising:

• a) a joint end sleeve including first and second co-axial sections with circular cross sections and a third section for connection to a piping system, said joint end sleeve including a passing duct;
• b) said first section including a cylindrical end with an outside diameter slightly smaller than the inside diameter of the piping and at least one annular groove;
• c) said second section being axially adjacent to said first section, said second section including a cylindrical threaded section;
• d) a tightening ring having an external truncated-cone shaped surface and an internal cylindrical surface with a diameter slightly larger than the diameter of the piping, said tightening ring having on said internal cylindrical surface at least one annular edge to cooperate with said at least one annular groove in such a way that an inside diameter of said annular edge is substantially equal to the outside diameter of the piping;
• and
• e) a nut made of a material harder than the material used in the piping and with a hardness higher or equal to one used in said joint end sleeve, said nut having a first internal surface cylindrical with a diameter slightly larger than the outside diameter of the piping, said nut having a second internal truncated-cone shaped surface with a conicity substantially similar to the conicity of said tightening ring, the smaller diameter end of said internal truncated-cone shaped surface is adjacent said cylindrical internal surface, said truncated-cone shaped surface having a smaller diameter end a size larger than said diameter of said internal cylindrical surface, said internal truncated-cone shaped surface having a larger diameter end a size slightly larger than said smaller outside diameter of said tightening ring, said nut including an internal threaded surface with a pitch diameter slightly larger than the diameter of said internal cylindrical surface, said internal threaded surface being complementary to said cylindrical threaded section of said joint end sleeve.