Patents Assigned to Geotechnical Digital Systems Limited
  • Pressure source
    Patent number: 4566868
    Abstract: A liquid pressure source, e.g. for use in soil mechanics laboratories, has a piston-cylinder unit driven by a stepper motor: a pressure transducer indicates the liquid pressure and a digital feedback control unit responds to generate stepping pulses to maintain a desired pressure. A step counter can be included to provide an accurate indication of volume change, and backlash compensation may be provided by arranging that the counter, following a direction change, ignores motor steps until a pressure change occurs.
    Type: Grant
    Filed: September 11, 1981
    Date of Patent: January 28, 1986
    Assignee: Geotechnical Digital Systems Limited
    Inventor: Bruce K. Menzies