| 摘要 |
<p>PURPOSE: To prevent the damage of a part of an insertion port even when a propulsion pipe is pushed through a curve-form route and to improve the loading capacity of the propulsion pipe. CONSTITUTION: A notch part 11 extending in a groove-form manner from a spot in the vicinity of the outer peripheral surface of an insertion port to a slope 8c on the outer peripheral surface side is formed in an approximately triangular rib 8 for reinforcing a flange 7. When a propulsion pipe is pushed through a curved route, a flange 7 in a spot on the inner surface side B of the curve part of a pipe coupling and the end face 6 of a socket 2 are brought into firm contact with each other and in this case, a flange 7 and the part 8a, positioned closer to the flange 7, of the rib 8 are formed in such a manner to approach the part 8b, separated away from the flange 7, of the rib 8. A stress is blocked from being concentratedly transmitted to the part 8b, on the side separated away from the flange 7, of the rib 8.</p> |
