Patents Represented by Attorney Alastair W. Neill

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  • Valves
    Patent number: 5950673
    Abstract: A pilot operated check valve is provided for use in controlling the hydraulic leg 14 of a hydraulic mine roof support, the valve having means 23 to connect a leg extension port 18 to a return port 17 within the valve, when the valve is used to lower the leg 14. This provides more rapid operation than with prior art arrangements in which released pressure from the leg has to return from an extension port back to a remote spool valve controlling leg extension before reaching a return line.
    Type: Grant
    Filed: February 3, 1998
    Date of Patent: September 14, 1999
    Assignee: Joy MM Delaware, Inc.
    Inventor: Peter Elliott-Moore