# US 6,878,953 B2 · Optical measuring apparatus for measuring objects on machines

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- Number: US 6,878,953 B2
- Document ID: US6878953B2
- Status: Granted
- Kind: B2
- Application number: 10/678,075
- Filed: 2003-10-06
- Published: 2004-04-15
- Granted: 2005-04-12
- Earliest claimed: 1999-11-22
- Assignees: Renishaw PLC
- Inventors: Victor G Stimpson; Jon P Fuge; William K Davies; Norman J Leete; Colin T Bell
- Web page: https://patentgrep.com/patent/US6878953B2

## CPC

- B23Q 17/20: for indicating or measuring workpiece characteristics, e.g. contour, dimension, hardness
- B23Q 17/24: using optics {or electromagnetic waves}
- B23Q 17/2485: {using interruptions of light beams}
- G01B 11/005: {coordinate measuring machines}
- G01B 11/028: {by measuring lateral position of a boundary of the object (G01B11/022, G01B11/024, G01B11/04 take precedence)}
- G01B 21/047: {Accessories, e.g. for positioning, for tool-setting, for measuring probes}
- G01V 8/12: using one transmitter and one receiver
- H03K 17/94: characterised by the way in which the control signals are generated
- H03K 17/941: {using an optical detector (H03K17/968 takes precedence)}
- H03K 2217/94104: using a light barrier
- H03K 2217/94116: increasing reliability, fail-safe
- Y10T 408/14: Responsive to condition of Tool or tool-drive
- B23Q: DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING (tools of the kind used in lathes or boring machines B23B27/00); MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention teaches a method and apparatus for making measurement of an object on a machine, such as a machine tool, using an optical measuring apparatus which includes a light source for generating a beam of light which is incident on a detector. A detection signal is generated within the detector each time the beam is interrupted. The duration and/or frequency of the detection signals are evaluated and an output signal is emitted from the detection only if a further detection signal is present within the detector in a specified time interval from the generation of an earlier detection signal.

## Claims

### Claim 1

A method for making measurements of a rotating object and for producing an output, using an optical measuring apparatus which includes a light source which generates a beam of light and a detector for receiving the beam of light, comprising:
rotating the object;
causing a beam of light to be emitted from the light source;
displacing the object transversely relative to the beam;
detecting an extent of the beam of light at the detector while the object is being displaced transversely relative to the beam;
generating a signal from the detector when a predetermined extent of light is present at the detector;
delaying the output for at least one revolution of the object following the generation of the signal, and;
causing an output to issue from the apparatus only if the predetermined extent of light is present at the detector at the end of the delay.

### Claim 2

A method for making measurements of a rotating object and for producing an output, using an optical measuring apparatus which includes a light source which generates a beam of light and a detector for receiving the beam of light, comprising:
rotating the object;
causing a beam of light to be emitted from the light source;
displacing the object transversely relative to the beam;
detecting an extent of the beam of light at the detector while the object is being displaced transversely relative to the beam;
generating a signal from the detector when a predetermined extent of light is present at the detector;
delaying the output for at least one revolution of the object following the generation of the signal, and;
causing an output to issue from the apparatus only if the signal is present at the detector at the end of the delay.

### Claim 3

A method for making measurements of a rotating object and for producing an output, using an optical measuring apparatus which includes a light source which generates a beam of light and a detector for receiving the beam of light, comprising:
rotating the object;
causing a beam of light to be emitted from the light source;
displacing the object transversely relative to the beam;
detecting an extent of the beam of light at the detector while the object is being displaced transversely relative to the beam;
generating a signal from the detector when a predetermined extent of light is present at the detector;
causing a clock pulse to start, having a duration substantially equal to at least one revolution of the object, each time a signal from the detector is generated; and delaying the output until the end of the clock pulse.