Patent ID: 7717640

Claim:
A joint structure having a plurality of pipes, comprising: a first pipe having a tenon formed on an end face and a first mortice and a second mortice formed on an outer circumferential surface; a second pipe having a mortice formed on an end face and a first mortice and a second mortice formed on an outer circumferential surface; the end faces of the first and second pipes being joined to and in surface contact with each other over an entire thickness of the first and second pipes, the tenon on the end face of the first pipe being fitted to the mortice on the end face of the second pipe; wherein the tenon on the end face of the first pipe is fixed to the mortice on the end face of the second pipe, and the first pipe and the second pipe are fixedly joined to each other at a non-linear angle; and third and fourth pipes each having a first tenon and a second tenon on a respective end face; the third and fourth pipes respectively being joined to and in surface contact with each of the outer circumferential surfaces of the first and second pipes; the first tenon of the third pipe being fitted to the first mortice on the outer circumferential surface of the first pipe and the second tenon of the third pipe being fitted to the first mortice of the outer circumferential surface of the second pipe; the first tenon of the fourth pipe being fitted to the second mortice on the outer circumferential surface of the first pipe and the second tenon of the fourth pipe being fitted to the second mortice of the outer circumferential surface of the second pipe wherein the end faces of the first, second, third, and fourth pipes are collected at one location and joined to each other without requiring a joint member.