Patents Represented by Attorney Minoru Abe
  • Patent number: 5342568
    Abstract: A method for introducing a prestress into a concrete member includes the steps of passing a steel rod (2) through a hollow steel rod (1), applying a tensile force to the hollow steel rod (1), while using the steel rod (2) as a reaction support member, placing concrete (4) around the hollow prestressed steel rod (1), and hardening the concrete (4). The apparatus includes a flat bearing support plate that abuts the concrete to be prestressed, a jack and ram, a rigid support member for interconnecting the jack and ram to the bearing support plate, and a holding cylinder positioned between the bearing support plate and the jack and ram. The bearing support plate and a leading end of the holding cylinder are apertured and screw threadedly receive the threaded trailing end of a hollow steel rod. The trailing end of the steel rod is screw threadedly received by the trailing end of the holding cylinder.
    Type: Grant
    Filed: May 3, 1993
    Date of Patent: August 30, 1994
    Assignee: Oriental Construction Company
    Inventor: Tsutomu Yokota