Abstract: Tool-switching device for a machine for measuring coordinates wherein the tool is fastened on the tool-carrier and held by the action of elements exerting an axial force. The locking force is taken over symmetrically by the elements of a Boys connection, which increases the repeatability of the connection; in one embodiment, two pins or spheres are driven by a sliding bushing provided with two “V”-shaped slits or with two lateral gorges. In the subsequent embodiments, the pins are replaced by spheres, by levers or by a stirrup.

Abstract: A stylus is supported by an upper coupling member which is supported by a lower coupling member which is supported by a probe which is movably supported by a rail of a coordinate positioning machine. The coupling members are held together by a permanent magnet, and their relative positioning is established by first and second sets of positioning elements provided on the first and second coupling members respectively. The sets of positioning elements are mutually engagable in a plurality of angular orientations about the axis of the coupling to provide a plurality of angularly indexed positions at which the lower coupling member has stable and repeatable positions relative to the upper coupling member. The coupling is carried to the indexing dock where a carrier engages the lower coupling member, and the lower coupling member is released from the upper coupling member by energizing an electromagnet which repels the coupling members apart.