Two types of control systems are described. The type manufactured by Blaw Knox uses electro-mechanical devices; the other made by Grad-Line is designed with solid-state techniques. Both systems detect vertical deviations of the paver from a pre-set datum and then modify the oil supply to the hydraulic rams raising or lowering the screed tow points of the paver accordingly. Levels can be controlled in the direction of travel or transversely. The level sensor can be used with an accurately set tensioned wire alongside the paver, or act from a previously laid mat, kerb or haunch. An averaging beam up to 12 M long can be used to eliminate rapid fluctuations in the base. Accurate crossfall is maintained in the blaw knox unit by a sensor unit mounted on a horizontal cross-member fixed between the side arms of the paver. The sensor is actuated by a pendulum suspended from the cross-member. The grad-line equipment produces A 'dither' signal to counteract any overcorrecting of the paver. Crossfall is controlled by monitoring the slope of the screed using an accelerometer. Future developments may make it possible to correct the paver from measurements made ahead of it. /TRRL/

  • Corporate Authors:

    Embankment Press Limited

    Building 59, GEC Estate, East Lane
    Wembley, Middlesex HA9 7TQ,   England 
  • Authors:
    • Evans, P J
  • Publication Date: 1977-11


  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00174057
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Jun 28 1978 12:00AM