Patents Assigned to Hochtief Ag Vorm. Gebruder Helfmann
  • Tunnel lining form
    Patent number: 4621948
    Abstract: A tunnel casing is formed by cylindrical casing sections whose proximal flanges are not only bridged by the usual drawbolts tending to pull the casing sections toward one another, seals and centering elements, but also are provided with wedge or hydraulic spacers which can fix the gap widths at the respective joints by hydraulic or wedge blocking to take up pressure forces which cannot be sustained by the drawbolts.
    Type: Grant
    Filed: November 21, 1984
    Date of Patent: November 11, 1986
    Assignee: Hochtief Ag Vorm. Gebruder Helfmann
    Inventor: Volker Hentschel