Patents Assigned to Wilkinson Heavy Precast Limited
  • Manhole with extension wings
    Patent number: 6309139
    Abstract: A manhole for a storm sewage system comprising a structure having at least two outwardly extending substantially vertical flat panels projecting outwardly from the exterior surface a predetermined distance on opposite sides of the base portion of the manhole.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: October 30, 2001
    Assignee: Wilkinson Heavy Precast Limited
    Inventor: John Tran-Quoc-Nam