Abstract: A telescopic swivel pipe joint for coupling a pair of axially spaced pipes each having a connection end comprising a pair of joint connectors each connected to the connection end of a corresponding pipe and having a spherical bearing surface, a pair of main joint tubes each having a cylindrical portion and provided at one end thereof with an integral spherical portion for slidable contact with the bearing surface of a corresponding joint connector, and an auxiliary joint tube removably connected at both ends thereof to the respective cylindrical portions of the main joint tubes, wherein the auxiliary joint tube is telescopic in itself or telescopically fitted at one end thereof to the cylindrical portion of a corresponding main joint tube.

Abstract: A double nut comprising a locking nut body having a threaded axial bore, the locking nut body being formed with a recess defined by an annular internal surface and arranged in communication with the axial bore, a tightening nut body having a threaded axial bore coaxial with and corresponding in diameter to the axial bore of the locking nut body, the tightening nut body being formed with an annular axial projection insertable into the recess and having an external surface, at least one of the internal and external surfaces being conical with a diameter decreasing gradually in a direction of insertion of the axial projection into the recess, one of the recess and the axial projection being eccentric with both of the axial bores, and a connecting web adapted to break at a predetermined circumferential shearing force and extending radially to connect the external surface to the internal surface.