| 摘要 |
A pipe coupling comprising a tubular spigot (1) for insertion into the end of a pipe (8) and a sleeve (7) for positioning over the end of the pipe (8) into which the spigot (1) has been inserted. The outer surface of the spigot (1) defines a series of circumferential ribs (4) separated by circumferential grooves (5). When the coupling is assembled the sleeve (7) traps the pipe end (8) against the spigot (1) such that the ribs (4) are pressed into the inner wall of the tube and material displaced by the ribs (4) is pressed into the grooves (5). The mean cross-sectional area of the space defined between the radially outer surface of the spigot (1) and the radially inner of the sleeve (7) in the assembled coupling reduces from the end (2) of the spigot which is first inserted into the pipe. Thus, the compression of the pipe end (8) increases towards the end of the pipe, ensuring that relatively thick walled pipes are tightly gripped close to the spigot end (2) whereas relatively thin walled pipes are tightly gripped by the ribs (4) and grooves (5) remote from the spigot end (2). |
