Expansion joint

Claim 1

An expansion assembly for coupling first and second lengths of pipe, said expansion joint comprising: a. a rotatable right angle joint coupling a first pipe section at right angles to said first length of pipe; b. a second pipe section coupled at right angles by a rotatable right angle joint to said first pipe section and rotatable about the longitudinal axis of the first pipe section; c. a rotatable right angle joint coupling a third pipe section at right angles to the second length of pipe; d. a rotatable right angle joint coupling a fourth pipe section at right angles to said third pipe section and rotatable around the longitudinal axis of said third pipe section; and e. a fifth pipe section intercoupling said second pipe section and said fourth pipe section by a rotatable right angle joint at each end of the fifth pipe section, such that the second and fourth pipe sections are rotatable around the longitudinal axis of the fifth pipe section; and wherein said joints includes a circumferential groove on the internal surface therein and grooves spaced circumferentially on the outer surface thereof positioned adjacent said internal groove, and wherein the pipe section being joined to said joint includes a cooresponding groove on the outer surface thereof confronting the internal groove of the joint, and further including a key member insertable through the outer groove of the joint into the channel formed by the confronting grooves of the joint and pipe section.