| 摘要 |
1,222,072. Piston rings. WELLWORTHY Ltd. 10 April, 1968 [12 April, 1967], No. 16880/67. Heading F2T. A piston ring 1 is coated on its working surface with wear-resistant material 4 which, in order to facilitate running-in, is formed on its outer peripheral surface with axially spaced circumferentially extending lands 5 or a single helical land. The ring 1 may be of cast iron or steel and the coating 4, which may be chromium, molybdenum, aluminium oxide or tungsten carbide, may be deposited in a circumferented channel (6), Fig. 1 (not shown), in the ring. As shown in Fig. 3, the coating 4 may be covered with an overlay 8 of soft material, e.g. copper, tin, P.T.F.E., or silver, which fills the grooves between the lands 5.
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