Patent ID: 7559581

Claim:
A coupling structure for use with a pipe, the coupling structure comprising: a tubular inner sealing portion formed from an elastic material, the tubular inner sealing portion having an abutment surface configured to abut against an inner circumference of the pipe; a tubular outer sealing portion formed from an elastic material, the tubular outer sealing portion having an abutment surface configured to abut against an outer circumference of the pipe, and an axial end of the tubular outer sealing portion being connected to the tubular inner sealing portion so as to enclose an end of the pipe; and a fastener for holding and fastening the pipe to the tubular inner sealing portion and the tubular outer sealing portion in a radially inward direction and a radially outward direction respectively, wherein one of an inner circumference of the tubular outer sealing portion and an outer circumference of the tubular inner sealing portion is fabricated into wave form having concave sections and convex sections arranged alternately in an axial direction, and another of the them is fabricated into a smooth cylindrical form, wherein the concave sections and convex sections are fabricated into helical forms in a circumferential direction, and wherein the fastener comprises an inner ring that is fit into a recess formed on an end portion of the inner circumference of the tubular inner sealing portion, the end portion being on an opposite side in the axial direction from a junction connecting the tubular outer sealing portion and the tubular inner sealing portion.