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).

  • Patent number: 8939008
    Abstract: 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: Grant
    Filed: July 20, 2011
    Date of Patent: January 27, 2015
    Assignee: Renishaw PLC
    Inventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
  • Publication number: 20110277534
    Abstract: 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: Application
    Filed: July 20, 2011
    Publication date: November 17, 2011
    Applicant: Renishaw plc
    Inventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
  • Patent number: 8001859
    Abstract: 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: Grant
    Filed: June 26, 2009
    Date of Patent: August 23, 2011
    Assignee: Renishaw PLC
    Inventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
  • Publication number: 20100005852
    Abstract: 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: Application
    Filed: June 26, 2009
    Publication date: January 14, 2010
    Applicant: Renishaw plc
    Inventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
  • Patent number: 7568373
    Abstract: 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: Grant
    Filed: September 22, 2004
    Date of Patent: August 4, 2009
    Assignee: Renishaw PLC
    Inventors: David Roberts McMurtry, Geoff McFarland, Kenneth Cheng-Hoe Nai, Stephen James Trull, Nicholas John Weston
  • Patent number: 7533574
    Abstract: 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: Grant
    Filed: November 15, 2004
    Date of Patent: May 19, 2009
    Assignee: Renishaw PLC
    Inventors: David R. McMurtry, Geoff McFarland, Kevyn B. Jonas
  • Publication number: 20070051179
    Abstract: 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: Application
    Filed: November 15, 2004
    Publication date: March 8, 2007
    Applicant: Renishaw plc
    Inventors: David McMurtry, Geoff McFarland, Kevyn Jonas
  • Publication number: 20060266100
    Abstract: 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: Application
    Filed: September 22, 2004
    Publication date: November 30, 2006
    Applicant: Renishaw pic
    Inventors: David McMurtry, Geoff McFarland, Kenneth Nai, Stephen Trull, Nicholas Weston
  • Patent number: 7127825
    Abstract: 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: Grant
    Filed: June 13, 2002
    Date of Patent: October 31, 2006
    Assignee: Renishaw PLC
    Inventors: David Roberts McMurtry, Geoff McFarland
  • Publication number: 20040163268
    Abstract: 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: Application
    Filed: November 19, 2003
    Publication date: August 26, 2004
    Inventors: David Roberts McMurtry, Geoff McFarland
  • Patent number: 6718647
    Abstract: 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: Grant
    Filed: February 14, 2002
    Date of Patent: April 13, 2004
    Assignee: Renishaw PLC
    Inventors: Stephen James Trull, Geoff McFarland, Andrew Daniel Huber, Peter George Lloyd
  • Patent number: 6633143
    Abstract: 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: Grant
    Filed: September 28, 2001
    Date of Patent: October 14, 2003
    Assignee: Renishaw PLC
    Inventors: Nicholas J. Weston, Kenneth C-H Nai, Geoff McFarland, David R McMurtry
  • Publication number: 20020162230
    Abstract: 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: Application
    Filed: September 28, 2001
    Publication date: November 7, 2002
    Inventors: Nicholas J Weston, Keneth C-H Nai, Geoff McFarland, David R McMurtry
  • Publication number: 20020104227
    Abstract: 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: Application
    Filed: February 14, 2002
    Publication date: August 8, 2002
    Inventors: Stephen James Trull, Geoff Mcfarland, Andrew Daniel Huber, Peter George Lloyd
  • Patent number: 5886352
    Abstract: 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: Grant
    Filed: July 1, 1997
    Date of Patent: March 23, 1999
    Assignee: Reinshaw plc
    Inventors: David A Wright, Geoff McFarland