Connecting device for corrugated pipe and coupling method thereof

A corrugated pipe connection device comprising:

• a corrugated pipe comprising a groove and a ridge that are successively and alternately formed;
• a nut into which one side portion of the corrugated pipe is inserted, wherein the nut has a screw-thread on an inner circumferential surface thereof;
• a clamping ring being formed in a ring shape cut at one place thereof and comprising an inner portion formed convexly in a radially inward direction of the corrugated pipe to be inserted into the groove of the corrugated pipe and an outer portion protruded in a radially outward direction from the inner portion, wherein the outer portion comprises an outer circumferential surface;
• and
• a socket having a screw-thread on an outer circumferential surface thereon onto which the nut is screwed,
• wherein the inner circumferential surface of the nut is formed with a first seat portion on which the clamping ring is seated and a second seat portion on which the outer protrusion is seated,
• wherein the socket is formed on a front surface thereof with an outer protrusion having no screw-thread thereon protruding towards the clamping ring in a longitudinal direction of the socket, wherein an outer diameter of the outer protrusion is smaller than an outer diameter of the screw-thread of the socket,
• wherein the outer protrusion is configured to be inserted into a gap between the inner circumferential surface of the nut and the outer circumferential surface of the clamping ring, such that the outer circumferential surface of the outer protrusion and the second seat portion of the nut come into a close surface contact to each other,
• wherein a distal end of the corrugated pipe is configured to be pressed between the front surface of the socket and the clamping ring,
• wherein the front surface of the socket is formed with an inner protrusion so that the inner protrusion is spaced radially inwards apart from the outer protrusion,
• wherein a groove is formed between the inner protrusion and the outer protrusion, and
• wherein the inner protrusion is formed so as to face the one side surface of the clamping ring for pressing the distal end of the corrugated pipe towards the clamping ring.