Abstract: A girder for supporting a movable body has a truss structure of a cross-sectional shape forming an isosceles triangle with a horizontal base. The truss structure is formed of three main tubes of a circular cross section that are located in positions corresponding to respective corners of the triangle and extend continuously over the length of the girder. A plurality of branch tubes of circular cross section are fixed at their ends to respective pairs of the main tubes by joint pieces, such that three branch tubes lie in a plane extending through the respective joint pieces perpendicular to the longitudinal axes of the main tubes so as to form the isosceles triangle. A rail support is secured to each main tube of the base of the isosceles triangle at a position disposed upwardly and outwardly of the center thereof, and a rail, along which the movable body is traversable, is supported on each rail support.

Abstract: A joint for interconnecting a main pipe and an auxiliary pipe of a framework structure. The joint is adapted to envelope the main pipe and to be fixed thereto and is provided with an expanded portion. The auxiliary pipe is adapted to be fixed to the expanded portion of the joint so that the main pipe and the auxiliary pipe are connected to each other through the joint.