Renishaw Plc

Reinshaw Plc

Geoff McFarland

David R McMurtry

Nicholas John Weston

Stephen James Trull

Kenneth Cheng-Hoe Nai

Kevyn Barry Jonas

David Allan Wright

Peter G Lloyd

Kenneth C-h Nai

Andrew Daniel Huber

A method of calibrating an articulating probe head comprising the steps of measuring an artifact of known dimensions with the workpiece sensing probe mounted on the articulating probe head, in which the articulating probe head is unlocked. An error functional map is generated corresponding to the difference between the measured and known dimensions of the artifact. Subsequent workpieces are measured with the articulating probe head unlocked and the corresponding correction applied. The true dimensions of the artifact may be determined by measuring it with a probe mounted on an articulating probe head in which the axes of the articulating probe head are locked. A mechanical lock is provided to lock the axes of the articulating probe head.

Calibration artefact for calibrating an articulating probe head

A method of calibrating an articulating probe head comprising the steps of measuring an artefact of known dimensions with the workpiece sensing probe mounted on the articulating probe head, in which the articulating probe head is unlocked. An error functional map is generated corresponding to the difference between the measured and known dimensions of the artefact. Subsequent workpieces are measured with the articulating probe head unlocked and the corresponding correction applied. The true dimensions of the artefact may be determined by measuring it with a probe mounted on an articulating probe head in which the axes of the articulating probe head are locked. A mechanical lock is provided to lock the axes of the articulating probe head.

Method of error compensation in a coordinate measuring machine

A method of error compensation for measurements taken using a co-ordinate positioning apparatus comprising an articulating probe head having a surface detecting device. The surface detecting device is rotated about at least one axis of the articulating probe head during measurement. The method comprises the steps of: determining the stiffness of the whole or part of the apparatus; determining one or more factors which relate to the load applied by the articulating probe head at any particular instant, and determining the measurement error at the surface sensing device caused by the load.

Method of error compensation

A measurement probe () has a stylus part () connected to it by means of a ball and cup universal joint (FIGS.and). The stylus part () is reorientable relative to the probe and during reorientation is held by means of magnetism or suction to an at tractor () whilst the probe () is moved. The stylus part () is held in static relation to the probe during measurement by means of magnetism or vacuum. The stylus part () may be exchanged for another, e.g.or' at rack (). During exchange the magnetism or vacuum holding () the probe and stylus part in static relation is reduced.

Stylus orientation

A measurement probe ( ) is disclosed having strain sensing elements ( ) mounted on spokes ( ) of a strain sensing member ( ). The member ( ) is disposed in parallel and spaced from a diaphragm ( ). Inner portions of the member and diaphragm are connected to a stylus holder ( ) and outer portions of the member and diaphragm are connected to probe body ( ). The probe can be used to produce a signal when contact force on the stylus ( ) is within an adjustable upper and lower limit, and is thereby suited to use with a manually manipulatable coordinate measuring device.

Force sensing probe

An articulating probe head includes motors and for driving respective output shafts and about respective orthogonal axes z and x to move a stylus over the surface of a workpiece under the control of a controller . At least one of the motors is inertia balanced by mounting the stator of the motor on bearings to allow it to rotate in opposition to the rotation of the rotor . Control of the speed of the spinning stator is achieved by connecting it to the winding assembly of an additional &ldquo;back-to-earth&rdquo; motor the magnet assembly of which is connected to the housing. The motor acts as a brake to prevent overspeeding of the rotatable stator, and can have power supplied to it to ensure that the stator does not slow down excessively when the main motor is running at constant angular velocity. Control of the power supply to the motors is achieved by the controller

Growing community of inventors

Dursley, United Kingdom

Geoff McFarland