Patents Assigned to Sanwa Kokan Kabushiki Kaishas
  • Patent number: 4726211
    Abstract: A method of cold drawing seamless metal tubes each having an upset portion on each end. A draw bench used for carrying out the method of this invention comprises a die control device, a plug control device including a plug having large and small diameter bearing portions and a draw unit. The die control device and the plug control device are movable with each other for changing a cross sectional reducing area between the reducing die and the plug. The method is characterized in that the cross sectional reducing area between the reducing die and the plug is preferably changed in accordance with the desired forms of a mother tube to be drawn by longitudinally transferring the reducing die and the plug and fixing them at the selected positions.
    Type: Grant
    Filed: May 1, 1986
    Date of Patent: February 23, 1988
    Assignee: Sanwa Kokan Kabushiki Kaishas
    Inventors: Yutaka Sunaga, Toshio Sakurai