| 摘要 |
PURPOSE: To improve the strength of the biting projection of a dropping-out preventing tool by providing a circular theft part in the corner angle part between the diameter contracted surface on a joint body side and the dropping-out preventing tool inner surface, and dispersing a stress to the whole projection, when a large force is added to the foot part of the projection, without collecting the stress to the foot part. CONSTITUTION: The joint body 20 consisting of forgeable cast iron material of a tube fitting for polyethylene tube connection has a male screw 21 on the end part outside, and a push ring 30 having integrally having an inward collar 32 is screwed to it. A packing 40 is installed between the packing chamber 22 of the joint body 20 and a pipe 7 inserted thereto, and this packing 40 holds the outer surface of the connecting pipe 7 in cooperation with a dropping-out preventing tool 60 the diameter of which is contracted by the tapered inner surface 33 of the push ring 30. This dropping-out preventing tool 60 has three biting projection streaks 62 formed on the inner circumferential side, and a circular theft part 65 is provided in the corner angle part between the diameter contracted surface 64 of the projection 62 and the dropping-out preventing tool inner surface 63, whereby a stress added to the projection foot part is dispersed. |
