Patents by Inventor Geoff McFarland
Geoff McFarland has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8939008Abstract: 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.Type: GrantFiled: July 20, 2011Date of Patent: January 27, 2015Assignee: Renishaw PLCInventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
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Publication number: 20110277534Abstract: 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.Type: ApplicationFiled: July 20, 2011Publication date: November 17, 2011Applicant: Renishaw plcInventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
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Patent number: 8001859Abstract: 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.Type: GrantFiled: June 26, 2009Date of Patent: August 23, 2011Assignee: Renishaw PLCInventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
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Publication number: 20100005852Abstract: 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.Type: ApplicationFiled: June 26, 2009Publication date: January 14, 2010Applicant: Renishaw plcInventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
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Patent number: 7568373Abstract: 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.Type: GrantFiled: September 22, 2004Date of Patent: August 4, 2009Assignee: Renishaw PLCInventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
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Patent number: 7533574Abstract: 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.Type: GrantFiled: November 15, 2004Date of Patent: May 19, 2009Assignee: Renishaw PLCInventors: David R. McMurtry, Geoff McFarland, Kevyn B. Jonas
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Publication number: 20070051179Abstract: 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.Type: ApplicationFiled: November 15, 2004Publication date: March 8, 2007Applicant: Renishaw plcInventors: David McMurtry, Geoff McFarland, Kevyn Jonas
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Publication number: 20060266100Abstract: 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.Type: ApplicationFiled: September 22, 2004Publication date: November 30, 2006Applicant: Renishaw picInventors: David McMurtry, Geoff McFarland, Kenneth Nai, Stephen Trull, Nicholas Weston
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Patent number: 7127825Abstract: A measurement probe (10) has a stylus part (12) connected to it by means of a ball and cup universal joint (24/25 FIGS. 2 and 3). The stylus part (12) is reorientable relative to the probe and during reorientation is held by means of magnetism or suction to an at tractor (50) whilst the probe (10) is moved. The stylus part (12) is held in static relation to the probe during measurement by means of magnetism or vacuum. The stylus part (12) may be exchanged for another, e.g. 12a or 12b? at rack (100). During exchange the magnetism or vacuum holding (15) the probe and stylus part in static relation is reduced.Type: GrantFiled: June 13, 2002Date of Patent: October 31, 2006Assignee: Renishaw PLCInventors: David Roberts McMurtry, Geoff McFarland
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Publication number: 20040163268Abstract: A measurement probe (10) has a stylus part (12) connected to it by means of a ball and cup universal joint (24/25 FIGS. 2 and 3) The stylus part (12) is reorientable relative to the probe and during reorientation is held by means of magnetism or suction to an at tractor (50) whilst the probe (10) is moved. The stylus part (12) is held in static relation to the probe during measurement by means of magnetism or vacuum. The stylus part (12) may be exchanged for another, e.g. 12a or 12b′ at rack (100). During exchange the magnetism or vacuum holding (15) the probe and stylus part in static relation is reduced.Type: ApplicationFiled: November 19, 2003Publication date: August 26, 2004Inventors: David Roberts McMurtry, Geoff McFarland
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Patent number: 6718647Abstract: A measurement probe (10) is disclosed having strain sensing elements (36) mounted on spokes (38) of a strain sensing member (34). The member (34) is disposed in parallel and spaced from a diaphragm (42). Inner portions of the member and diaphragm are connected to a stylus holder (26) and outer portions of the member and diaphragm are connected to probe body (32). The probe can be used to produce a signal when contact force on the stylus (12) is within an adjustable upper and lower limit, and is thereby suited to use with a manually manipulatable coordinate measuring device.Type: GrantFiled: February 14, 2002Date of Patent: April 13, 2004Assignee: Renishaw PLCInventors: Stephen James Trull, Geoff McFarland, Andrew Daniel Huber, Peter George Lloyd
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Patent number: 6633143Abstract: An articulating probe head includes motors 12 and 18 for driving respective output shafts 14 and 20 about respective orthogonal axes z and x to move a stylus 22 over the surface of a workpiece under the control of a controller 26. At least one of the motors is inertia balanced by mounting the stator 32 of the motor on bearings 42 to allow it to rotate in opposition to the rotation of the rotor 34. Control of the speed of the spinning stator is achieved by connecting it to the winding assembly 46 of an additional “back-to-earth” motor 47 the magnet assembly 48 of which is connected to the housing. The motor 47 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 26.Type: GrantFiled: September 28, 2001Date of Patent: October 14, 2003Assignee: Renishaw PLCInventors: Nicholas J. Weston, Kenneth C-H Nai, Geoff McFarland, David R McMurtry
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Publication number: 20020162230Abstract: An articulating probe head includes motors 12 and 18 for driving respective output shafts 14 and 20 about respective orthogonal axes z and x to move a stylus 22 over the surface of a workpiece under the control of a controller 26. At least one of the motors is inertia balanced by mounting the stator 32 of the motor on bearings 42 to allow it to rotate in opposition to the rotation of the rotor 34. Control of the speed of the spinning stator is achieved by connecting it to the winding assembly 46 of an additional “back-to-earth” motor 47, the magnet assembly 48 of which is connected to the housing. The motor 47 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 26.Type: ApplicationFiled: September 28, 2001Publication date: November 7, 2002Inventors: Nicholas J Weston, Keneth C-H Nai, Geoff McFarland, David R McMurtry
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Publication number: 20020104227Abstract: A measurement probe 10 is disclosed having strain sensing elements 36 mounted on spokes 38 of a strain sensing member 34. The member 34 is disposed in parallel and spaced from a diaphragm 42. Inner portions of the member and diaphragm are connected to a stylus holder 26 and outer portions of the member and diaphragm are connected to probe body 32. The probe can be used to produce a signal when contact force on the stylus 12 is within an adjustable upper and lower limit, and is thereby suited to use with a manually manipulatable coordinate measuring device.Type: ApplicationFiled: February 14, 2002Publication date: August 8, 2002Inventors: Stephen James Trull, Geoff Mcfarland, Andrew Daniel Huber, Peter George Lloyd
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Patent number: 5886352Abstract: A readhead for an opto-electronic encoder includes a light source, an analyser grating and a detector. The light source illuminates a scale of the opto-electronic encoder such that the light passed on by the scale forms a periodic light pattern. The analyser grating interacts with the periodic light pattern to generate a resultant fringe pattern. The resultant fringe pattern is incident upon the detector which generates a plurality of phase shifted cyclically modulating signals upon relative movement of the readhead positioned in registration with the scale. Either the periodic light pattern or the resultant fringe pattern is a linear pattern while a remaining one of the periodic light pattern and the resultant fringe pattern is an angular pattern.Type: GrantFiled: July 1, 1997Date of Patent: March 23, 1999Assignee: Reinshaw plcInventors: David A Wright, Geoff McFarland