| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a floating prevention manhole which uses an adjustment ring composing a normal manhole as a floating preventing component, so that assembling construction is easily performed without increase of the number of components. <P>SOLUTION: An oblique wall pipe 6, an adjustment ring 7, a lid receiving frame 10, and an openable lid 11 are sequentially stacked on the top of direct wall pipes 4 and 5 so as to form a floating prevention manhole 1. The adjustment ring 7 having an external diameter larger than the external diameter of the direct wall pipes 4 and 5 comprises a flat plate portion 7a which is placed on the oblique wall pipe 6 and a weight portion 7b which is arranged along the outer peripheral edge of the flat plate portion 7a and has a thickness larger than the thickness of the flat plate portion 7a. <P>COPYRIGHT: (C)2013,JPO&INPIT |
