Abstract: By previously press-fitting a ring (40) into one end portion (12) of a tube (11), the one end portion (12) is held in the flared state. With an inner cylindrical portion (22) of the joint main body (20) having been inserted into this ring (40) while the one end portion (12) having been press-fitted into a recessed groove (21) to the innermost recess portion, a greatest wall thickness portion (41) of the ring is covered. In this state, with a cap nut (30) being screwed with the joint main body (20), the greatest wall thickness portion (41) of the ring is pressed against the inner cylindrical portion (22) together with the one end portion (12) through an outer cylindrical portion (23), and a hole peripheral edge (34a) of an insertion hole (34) of the cap nut is pressure-contacted with a bent portion (12c) of the tube by the ring (40).

Abstract: By previously press-fitting a ring (40) into one end portion (12) of a tube (11), the one end portion (12) is held in the flared state. With an inner cylindrical portion (22) of the joint main body (20) having been inserted into this ring (40) while the one end portion (12) having been press-fitted into a recessed groove (21) to the innermost recess portion, a greatest wall thickness portion (41) of the ring is covered. In this state, with a cap nut (30) being screwed with the joint main body (20), the greatest wall thickness portion (41) of the ring is pressed against the inner cylindrical portion (22) together with the one end portion (12) through an outer cylindrical portion (23), and a hole peripheral edge (34a) of an insertion hole (34) of the cap nut is pressure-contacted with a bent portion (12c) of the tube by the ring (40).

Abstract: A fusion joining device for plastic tubes with which a pair of clampers 30 is supported such that it can be pivoted between the closed position where the joint portion T1 is sandwiched from both sides through a pair of members for heat conduction 20 and the open position where the spacing between the pair of members for heat conduction 20 is widened; and a pair of heaters 40 made of a resistance heat generation material in the shape of a sheet is formed such that it is along the pair of members for heat conduction 20, respectively, in order to heat the joint portion T1 through the pair of members for heat conduction 20.

Abstract: A joint for tubings with which, in tightening the nut member (20), the friction torque applied to the first end face (32) of the control ring (30) by the bore peripheral face (25) of the internally threaded bore (21) of the nut member (20) is greater than the friction torque applied to the second end face (34) of the control ring (30) by the stopper portion (17) of the joint main body (10, and thus the nut member (20) is reliably turned together with the control ring (30) at the final stage of tightening the nut member (200, which allows the proper initial tightening position of the nut member (20) to be determined.

Abstract: The present invention relates to a method of constructing a tube joint wherewith one end T1 of a tubing T is heated to be softened; the softened end T1 of the tubing T is inserted into a drop-off prevention ring 30; the end T1 of the tubing T is upset by means of an upsetting core 50 such that the anchoring portion 35 of the drop-off prevention ring 30 bites into the softened end T1 of the tubing T; and the end T1 of the tubing T is cooled to be hardened with the anchoring portion 35 of the drop-off prevention ring 30 being kept biting into it, and to such tube joint.

Abstract: A joint for coupling tubes forming a large diameter portion near one end of a fluorocarbon resin tube and forming a fastened portion by clamping at a crimp portion of the large diameter portion with a cap nut includes of a main body of rigid resin joint having a cylindrical portion formed a ring-shaped groove and cut a bevel at its inner wall end and a hard cap nut having a inner shoulder formed an acute-angle hook. The major portion of the large diameter portion of the fluorocarbon resin tube is inserted into the ring-shaped groove. A tube clamp portion as a hermetic portion is formed to press hard a tube crimp portion against the inner wall end of the cylindrical portion with the inner shoulder of the hard cap nut by tightening the hard cap nut on an external thread of the outer wall of the cylindrical portion.