Abstract: An apparatus for adjusting the position of a work mounted on a machine tool. A base is fixed to a work table of the machine tool, and the position of a mounting member is adjusted with respect to the base. The work is mounted on a mounting surface of the mounting member. The positions in the Z-axis direction of central portions of the four sides of the mounting member are adjusted by first driving and fixing members so that a work surface of the work is along an X-Y plane. The position where the mounting member is rotated around the Z-axis is then adjusted by second driving and fixing members arranged in the central portions of the pair of opposite sides of the mounting member so that a plane of the work is parallel to an X-Z plane. Each of the driving and fixing members includes piezoelectric displacement elements for adjusting an amount of displacement in response to an applied voltage so as to fix the mounting member in a state where the amount of displacement is adjusted.

Abstract: A pipe joint comprising a joint body provided with an insertion hole into which a pipe to be joined is inserted to be retained and a screw member adapted to engage with a fixing hole bored in the joint body and to form a recessed part on the outer periphery of the pipe by the engagement thereof with the joint body. Turning direction of the screw member conforms to pipe insertion direction. When joining two pipes together, a set of screw members for tightly fixing the pipes to the joint body respectively are provided in such an arrangement as perpendicular with each other. A boring member such as a drill is provided on the tip of the screw member so as to form the recessed part on the periphery of the pipe by cutting.