Renishaw Plc

Michael John Wooldridge

Peter Kenneth Hellier

John Charles Ould

Jamie John Buckingham

Paul William Moore

Robert Charles D'Olier Umfreville

Jonathan Paul Fuge

Jack Francis Colebrooke

Ben Richard Holden

Stephen Peter Ewen

Kevin Cullivan

John Ould

Paul Moore

A measurement probe is described that includes a probe body, a stylus that is deflectable relative to the probe body, and a plurality of sensor elements for generating a sensor signal indicative of stylus deflection. An analyser is provided, optionally as part of a trigger unit, to analyse the sensor signals and issues a trigger signal to indicate the stylus has contacted an object. The analyser is arranged to combine a plurality of the sensor signals to generate a resultant deflection signal for comparison to a deflection threshold and is also arranged to detect oscillatory motion of the stylus by analysing at least one of the sensor signals. The analyser only issues a trigger signal when the resultant deflection signal crosses the deflection threshold and no oscillatory motion of the stylus is detected. The measurement probe may be used on a machine tool or other coordinate positioning apparatus.

Measurement probe apparatus and method

A method of scanning an object using an analogue probe mounted on a machine tool, so as to collect scanned measurement data along a nominal measurement line on the surface of the object, the analogue probe having a preferred measurement range. The method includes controlling the analogue probe and/or object to perform a scanning operation in accordance with a course of relative motion, the course of relative motion being configured such that, based on assumed properties of the surface of the object, the analogue probe will be caused to obtain data within its preferred measuring range, as well as cause the analogue probe to go outside its preferred measuring range, along the nominal measurement line on the surface of the object.

Method of measurement on a machine tool

An electro-magnetic brake which is switched between an operative braking position and an inoperative position by transient pulses of current. It is held passively in the operative and inoperative positions with little or no current. This prevents the generation of heat, which would affect the accuracy of measurements where the brake is used in dimensional measuring equipment. In one form, permanent and semi-permanent magnets are arranged in parallel, and the magnetic polarity of the arrangement is flipped by transient current pulses in a surrounding coil. A capacitor may provide a reservoir of current to activate the brake in the event of a power supply failure.

Braking system

A method of scanning an object using an analog probe mounted on a machine tool, so as to collect scanned measurement data along a nominal measurement line on the surface of the object, the analog probe having a preferred measurement range. The method includes controlling the analog probe and/or object to perform a scanning operation in accordance with a course of relative motion, the course of relative motion being configured such that, based on assumed properties of the surface of the object, the analog probe will be caused to obtain data within its preferred measuring range, as well as cause the analog probe to go outside its preferred measuring range, along the nominal measurement line on the surface of the object.

Method of measurement on a machine tool and corresponding machine tool apparatus

A measurement probe, for a co-ordinate positioning apparatus such as a machine tool, is described that includes a stylus holder that is deflectably mounted to a probe housing. One or more sensors are provided for sensing deflection of the stylus holder relative to the probe housing. A processor is included for producing a trigger signal when the deflection sensed by the one or more sensors meets a trigger condition, such as a deflection threshold. The probe also includes an accelerometer for measuring acceleration of the measurement probe. The trigger condition applied by the processor is alterable, during use, in response to the acceleration measured by the accelerometer. In this manner, false triggering can be suppressed.

Touch trigger measurement probe

A dimensional measurement probe () is mounted in a machine tool (), which reorientates the probe about at least one axis A. Strain gauges () sense when a stylus () of the probe contacts a workpiece (), to produce a trigger signal. False trigger signals may be produced when the probe is reorientated. To overcome this, the reorientation is detected by monitoring changes in the fluctuations of the strain gauge outputs, caused by vibrations of the stylus.

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Stroud, United Kingdom

Michael John Wooldridge