segments 4 the serrations 12 of the segments are thus forced radially inwards to engage the pipe 6 if tension is subsequently applied to the pipe 6 it is prevented from pulling out of the socket 5 by this engagement between the segments 4 and the pipe as the gripping ring is in the form of a series of segments 4 and can easily be pulled over even a distorted pipe of oval cross section the resistance to forces tending to pull the pipe away from the fitting is very large typically grater than that required to result in failure of a polyethylene pipe for example fig7 illustrates an alternative embodiment of the invention suitable for forming a seal with the inner wall of a pipe in fig7 a pipe 20 receives a tubular fitting body 21 around which are positioned a sealing ring 22 a force transmitting ring 23 segments 24 which may be identical to those illustrated in fig4 a tubular push ring 25 and a nut 26 engaging a thread 27 provided on the body 21 the nut 26 can be tightened to apply an axial load to the ring assembly thereby compressing the sealing ring against a shoulder 28 supported in the body 21 the axial load also forces the segments 24 radially outwards to grip the pipe 20 a significant advantage of the described arrangements is that gripping rings of different nominal diameter can be produced simply by adjusting the number of segments in each gripping ring thus a single basic component can be used to form gripping rings.