摘要 |
A groove is provided in either one or the other of a cylinder housing or the piston and a pressure sealing ring is mounted in this groove. A resilient ring is in surface engagement with the sealing ring and a semi-resilient ring, also in the groove, is disposed in engagement with the outer edge of the resilient ring whereby upon the application of surface pressure by the sealing ring against the resilient ring as a result of fluid pressure in the cylinder, the resilient ring is compressed. This expands it to a larger diameter which in turn expands the semi-resilient ring to a larger diameter for efficient sealing. A lip on the member with the groove therein projects outwardly for backing up the semi-resilient ring.
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