Abstract: A probe 8 comprises a housing 10 and a member 20 movable with respect to the housing onto which a stylus 12 may be mounted such that movement of the stylus results in movement of the member and a primary transducer 50, 52 for measuring movement of the member relative to the housing. The member may be located in a precisely defined rest position 22, 24 with respect to the housing, putting the probe in a mechanical datum position. For a combined transducer probe, this enables the primary transducer 52, 54 to be locked whilst enabling use of a secondary transducer 70. The primary transducer outputs can be datumed whilst in this mechanical datum position. Drive 40, 50, 60 or bias 26 means in one axis secure the member in its rest position in all axes.

Abstract: A rotary drive mechanism is disclosed comprising a housing, a first motor having a first rotor and a first stator connected to the housing and a second motor having a second rotor and a second stator connected to the housing characterised in that the second motor is mechanically independent of the first motor whereby acceleration torques of the first motor are at least partially inertia balanced by the second motor. The balancing may be effected by equal and opposite rotation of the second motor. Control means may be provided to provide the second motor with a current which is proportional to that supplied to the first motor. Also disclosed is a positioning device and a probe having the rotary drive mechanism.

Abstract: A module storage rack is disclosed e.g. a probe rack suitable for use with a carrier e.g. a probe measurement head which is movable relative to the rack for picking a module from the rack. The rack comprises a base member and a plurality of storage ports connected to the base for storing the modules, each port having an actuatable connecting or disconnecting tool for connecting or disconnecting a module to or from the carrier, and each storage port being movable relative to the base member the said relative movement providing the actuation of the tool wherein the said plurality of storage ports are movable together relative to the base. Additionally, there is disclosed a linkage having a plurality of pivotally interconnected rigid members being connected to the tool for causing the tool to connect or disconnect the module to or from the carrier. The linkage may be operated by movement of the rack or by alternative means.

Abstract: A method of inspecting a series of workpieces using a coordinate measuring apparatus, comprising the steps of: measuring a calibrated artefact on a coordinate measuring apparatus at a fast speed 28; generating an error map corresponding to the difference between the calibrated artefact and the measured artefact 30; measuring subsequent workpieces at the same fast speed 34 and correcting the measurements of the subsequent workpieces using the error map 36. The artefact may be one of the workpieces.

Abstract: A method of calibrating an analogue probe (10) having a stylus (12) with a workpiece-contacting tip (14) or a non-contact probe (26). A calibration artefact such as a calibration sphere (16) is mounted on a coordinate measuring machine (CMM) (18). The probe (10,26) is mounted on an arm (8) of the CMM and the probe is moved along a path whilst continually scanning the surface of the calibration artefact such that the probe is exercised throughout its working range. For an analogue probe (10) having a workpiece-contacting stylus (12), the path is such that the deflection of the stylus varies along the path For a non-contact probe (26) the path is such that there is variation of the radial distance between the path and the calibration artefact. The probe path may comprise a path parallel to a chord of the calibration sphere or a curved, e.g. a sinusoidal, path.