| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent troubles caused by dregs derived from press boring on the common wall of the outer tube and inner tube of a double tube for connecting the inner tube. <P>SOLUTION: The inner tube 2 is installed in the outer tube 1. The outer tube 1 and the inner tube are constructed in a unity with a part of the walls thereof shared. The inner tube 2 has side walls 21 facing each other that extend parallel with the radial direction of the inner tube 2 from the common wall 3 of the outer tube 1 and inner tube 2. The back wall 22 of the inner tube 2 that is located at the ends of the side walls 21 and faces the common wall 3 of the outer tube 1 and inner tube 2 is made not wider than the distance between the side walls 21. <P>COPYRIGHT: (C)2012,JPO&INPIT |
