| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an earthquake-resistant fitting of a novel structure to perform a jacking method by using the fitting. <P>SOLUTION: Grooves 15 and 12 allowing the axial movement of a lock ring 11 are formed in the fitting on a spigot 1 side and a socket 2 side. Normally, the lock ring 11 is brought into a state in contact with (or in proximity to) the inside end walls 12a and 15a of both grooves 12 and 15. When the spigot 1 is pulled out (when a pipe P is pulled out by an extraction force applied to the pipe P), the lock ring 11 is moved until coming into contact with the outside wall end wall 12b of the groove 12 of the socket 2 (tolerance of extraction L1), and the further extraction thereof is prevented by that contact (locking). To the contrary, when the spigot 1 is inserted, the lock ring 11 is moved until coming into contact with the outside end wall 15b of the groove 15 of the spigot 1 (push-in tolerance L2), and the further insertion thereof is prevented by that contact (locking). A distance L1 + L2 = L becomes an extension/retraction tolerance. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
