To facilitate the adjustment of the height of an apparatus of heavy duty by combining a bolt whose head bearing surface part is formed with a spherical surface shape and whose part of a cylindrical part under head is provided with longitudinal stripes, with a nut whose bearing surface part is provided with a spherical surface shape and whose inner periphery is formed with a through-hole having longitudinal stripes.

A bolt 3 whose bearing surface part is formed with a spherical surface seat 1 and whose outer periphery under head is provided with longitudinal stripes 2 is inserted in a mounting hole 11 formed a part of flange metal fitting 10 together with a washer 8. A nut 6 whose inner periphery is formed with a hole 5 with longitudinal stripes and whose bearing surface part is formed with a spherical surface seat 4 is fitted in a longitudinal groove 2 together with a washer 9, and is tightened and fixed by a tightening nut 7. As a result, both of rotation transmission capability and linear mobility which the longitudinal groove shape owns and oscillating capability which the spherical surface shape owns can be attained, thus it is possible to facilitate the installation of an apparatus even on an inclined floor surface, and height adjustment.