Patent ID: 6981722

Claim:
A pipe coupling device comprising: a main body defining a main body passage hole to permit communication between inside the main body passage hole and outside the main body passage hole; a fixing screw member joined to the main body and surrounding a periphery of the main body passage hole, the fixing screw member having external threads formed on its outer peripheral surface, and exhibiting a substantially hollow cylindrical hollow shape; and a sleeve inserted in the fixing screw member; a tilt-preventing gap and a mouth deformation allowing gap being defined between the sleeve and the fixing screw member, the tilt-preventing gap and the mouth deformation allowing gap being axially in series; a pipe fastening screw member that is coupled to a pipe so as to be rotatable with respect to a tip end thereof, the pipe fastening screw member having internal threads formed on an inner peripheral surface thereof engaged with the external threads of the fixing screw member, whereby: an intra-pipe passage defined in the pipe communicates with the main body passage hole through a sleeve passage hole formed at a center of the sleeve; a first convergently tapered portion formed at said tip end of the pipe presses against a first pressure bearing surface formed at a first end of the sleeve to form a first seal portion; and a second convergently tapered portion formed at a second end of the sleeve presses against a second pressure bearing surface formed at an opening portion of the main body passage hole to form a second seal portion, wherein the mouth deformation allowing gap is defined radially outside of and axially overlapping with the first pressure bearing surface and has a radial dimension that is larger than a radial dimension of the tilt-preventing gap such that a clamping load applied to the first pressure bearing surface of the sleeve substantially eliminates the tilt-preventing gap to prevent tilting of the sleeve within the fixing screw member and allows the first end of the sleeve to freely radially deform.