US Patent 7516989 Piping connector and method of fabricating the same

A pipe connector for connecting a first pipe and a second pipe includes a socket attached to an end of the first pipe and a plug attached to an end of the second pipe, wherein the plug is inserted into the socket. An inner periphery of the socket is provided with a seal ring for sealing an interval between the inner periphery of the socket and an outer periphery of the plug in an airtight manner and a hold ring for restricting movement of the seal ring in an axial direction. The hold ring includes a groove in a ring-like shape for constituting a burr storing space at an outer periphery thereof and is welded to the inner periphery of the socket by ultrasonic welding.