A push fit attachment

摘要

A push fit attachment for connection to a pipe (A) push fitted into the attachment, the attachment comprising an outer tubular cover open at at least one end to receive the pipe and containing a grip ring (20) to grip the inserted pipe. The grip ring (20) has a cylindrical rim (30) and an annular array of teeth (34) in which each tooth (34) extends generally radially with respect to an axis of the annular array and with circumferential spacing (36) between adjacent teeth. Each tooth has a radially inner tip (44) comprising an edge (46) extending generally circumferentially, and the annular array is disposed in a generally frusto-conical array with a narrower end of the frustum of cone facing generally along a direction (Z) of insertion of a said pipe (A) through the grip ring from the open end of the cover. Within the frustum each tooth (34) has a main surface (42) facing in a general direction towards the open end of the cover. Each tooth has a said edge (46) comprising first and second longitudinal edge portions (48, 50, 54) and two points (60, 62) at an intersection of aforesaid edge portions. The second edge portion (54) forms a side of a scallop shaped notch (54) in the tooth at the tip (44) thereof and extending into tooth material radially outwards beyond each point (60, 62). At the tip (44) the tooth (34) is formed so that the points (60, 62) each extend out of said main surface (42) such that the point faces or points in a pointing direction (64 or 66) inwardly of the ring. The pointing direction (64 or 66) has a component of direction (68) opposite to the direction (Z) of tube insertion such that each point (60, 62) tends to dig into a said tube (A) when an attempt is made to withdraw the tube in the opposite direction to (Z) when the attachment is in use.