Subclass 1/32: Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members (B23Q 37/00 takes precedence) Movable or adjustable work or tool supports characterised by constructional features relating to the co-operation of relatively movable members; Means for preventing relative movement of such members Relative movement obtained by co-operating spherical surfaces, e.g. ball-and-socket joints