O-ring seal with high resilience - has core of coiled wire spring enclosed in sheath of flexible plastic

摘要

An O-ring seal has a core made from a length of coiled wire spring. The wire (4) is of rectangular cross-section with the dimension chosen to give the required resilience of the O-ring. A gap (5) is formed between successive coils equal to about one tenth of the width of the wire section. The ends of the coil are joined together to make a torus and the ring is then enclosed in a sheath of plastic such as P.T.F.E. This sheath may be formed by wrapping a piece of platic sheet around the coil to form several layers. Alternatively separate sheets may be used, the ends of each sheet being butt welded together.