| 摘要 |
<p>PURPOSE:To secure water passages at the time of a decrease in diameter of a tube due to a pressing load by forming side wall portions of a reinforcing hollow projecting stripe provided in a corrugate tube main body thicker toward the lower portion thereof, and setting bending strength of the side wall portion of a top portion lower than that in the side portion. CONSTITUTION:A corrugate tube 1 is provided with a corrugate tube main body 2 and reinforcing hollow projecting stripes 3 spirally formed on the surface of the main body 2. Both side wall portions 3b of the hollow projecting stripe 3 are formed thicker toward the lower portion thereof, and the top wall portion 3c of the hollow projecting stripe 3 is formed thinner than the side wall portion 3b. Upon applying a pressing load onto the corrugate tube 1 having the above- mentioned constitution under the ground,l buckling is first generated in the top portion of the corrugate tube 1, and at last, the cross section of the tube 1 is deformed into a spectacle shape. For further deformation, such a large pressing load as not to be really supposed is required. Therefore, two right and left water passages can be secured under a normal pressing load in the case of the deformation of the spectacle shape.</p> |
