To improve appearance of a finished product, to suppress production of a waste material and to reduce material cost by preventing leakage of a hydraulic material charged between an outer tube and an inner tube when a laminated tube obtained by forming a hydraulic curing body layer between the outer tube and the inner tube is manufactured.
The inner tube is arranged along the outer tube so that at least one end thereof is located inside the outer tube having both end parts opened in an axial direction. A sealing member is arranged so that one end of the inner tube is covered from the opening direction of the outer tube and is joined to the inner wall of the outer tube in order to seal a space between the outer tube and the inner tube. The hydraulic curing body layer is formed by charging the hydraulic material between the outer tube and the inner tube to manufacture the laminated tube. When the laminated tube is manufactured, a leakage prevention implement prevents leakage of the hydraulic material from a clearance which is formed between one end part of the inner tube and the sealing member and is opened toward the radial direction of the inner tube. The leakage prevention implement includes a sealing means which is arranged along the clearance so as to seal the clearance, and an energizing means which energizes the sealing means from the inside of the inner tube in the radial direction to the outside.
TAKETSU HITOMI
KITAGAWA AKIRA
YAMASHITA MASAHIRO
OKAMOTO YOSHIKAZU
FUNAKOSHI YUSUKE
KURIMOTO CONCRETE IND LTD
OKAMOTO KENSETSU YOHIN SEISAKU
Seiichi Yakumaru
Hiroaki Nakatani
Yuichi Koyama