Control apparatus

Claim 1

An improved control apparatus, comprising: a cylinder having one end closed to form a chamber and provided with a pair of apertures apart from each other in the axial direction of the cylinder, a control fluid being introduced into and discharged from the chamber through said apertures; a piston having a head movable within the chamber in its axial direction between the pair of apertures, and a rod integral with the head, said rod extending outward through the bottom of the cylinder; control means variably extending inside the chamber through the closed one end, the sliding motion of the piston head being defined by the control means and the bottom of the cylinder; an adaptor for fixedly mounting the control apparatus to a member to be controlled; said adaptor having an externally threaded part formed at one end thereof; coupling means for connecting the cylinder to the adaptor, said coupling means being rotated to move the cylinder in its axial direction without rotating the cylinder and having an internally threaded annular part formed at one end thereof and meshing annularly around the externally threaded part of the adaptor; the coupling means having first connecting means provided round the outer circumference of the cylinder and being capable to abut the cylinder, the rotation of the first connecting means serving to move the cylinder in its axial direction; rotation preventing means to prevent rotation of said adaptor and said cylinder during rotation of said coupling means, said rotation preventing means including second connecting means permitting the cylinder to move in its axial direction relative to the adaptor; the cylinder having an annular groove formed along the outer circumference thereof, the first connecting means having an indwardly projected member engaged with the annular groove; the second connecting means having a pin whose one end is fixed to one of the cylinder and the adaptor with the other end slidable along an axial hole bored in the other member; the inwardly projected member of the first connecting means having an element engaged with the annular groove of the cylinder via a radial hole bored through the coupling means, and the pin of the second connecting means being fixed to one of the cylinder and the adaptor by forcedly inserting the pin into an axial hole provided therein.