Abstract: A joint (and method) connects synthetic resin corrugated pipes, each of the corrugated pipes including a pipe wall having sectionally rectangular wall portions and sectionally circular wall portions disposed alternately in a longitudinal direction of the corrugated pipe. The sectionally circular wall portions each include an annular-shaped protrusion projecting outwardly from the sectionally circular wall portions disposed substantially at a center of the sectionally circular wall portion between adjacent sectionally rectangular wall portions in the longitudinal direction.

Abstract: A connector for mounting a pipe member (P) having a spiral-shaped wall to a through hole (h) formed in a wall member (W), the connector comprises a bellmouth (1), a holder (2) and a waterproof packing member (3). The bellmouth (1) includes an engaging projection (13) which is formed on the outer periphery (12) of a cylindrical-shaped portion (11) thereof and is engageable with the inner peripheral surface of the pipe member (P). The holder (2) includes a spiral-shaped projection (23) which is formed on the inner peripheral surface (22) of a cylindrical-shaped portion (21) thereof and fittingly engageable with the outer periphery spiral-shaped portion of the pipe member (P). The waterproof packing member (3) is disposed between the wall member (W) and the holder (2).

Abstract: A corrugated synthetic resin pipe comprises a pipe wall including sectionally rectangular wall portions and sectionally circular wall portions disposed alternately in a longitudinal direction of the pipe. Each of the sectionally circular wall portions has an annular projected portion disposed at a substantially center of the sectionally circular wall portion between adjacent sectionally rectangular wall portions in the longitudinal direction, to thereby prevent parallel layout or stack layout of pipes from being disturbed.

Abstract: A pipe having a substantially square cross section portion and a substantially circular cross section portion are disposed alternately in the axial direction of the pipe. The thickness of the circular portion is set uneven in the circumferential direction. In particular, the thickness of the portions of the circular portion that correspond to the corner portions of the square portion is set larger than the thickness of the portions that correspond to the central portions of the respective sides of the square portions. Accordingly, a pipe having corner portions with increased pressure deformation resistance is obtained. Also, the pipe is capable of being manufactured in a high efficiency manner.