Touch probe and signal processing circuit therefor
US5435072A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1993 |
| Grant date | Jul 25, 1995 |
| Priority date | — |
| Expiry date | Dec 16, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A touch trigger probe incorporates piezoelectric sensors 50, whose outputs are processed by an interface circuit. The interface circuit discriminates between signals generated from the piezoelectric sensors 50 as a result of machine vibration and those generated as a result of a genuine measurement event, by the use of a timing circuit 90. The timing circuit 90 compares the time intervals (t.sub.1 -t.sub.2);(t.sub.2 -t.sub.3) between attainment of first 1.sub.1 and second 1.sub.2, and second 1.sub.2 and third 1.sub.3 output signal levels from the sensor 50, and upon the basis of this comparison validates (or rejects) measurements made with the probe. Additionally, the interface determines whether measurements made with the probe are taken upon the basis of outputs generated by the sensors 50 due to a shock wave in the stylus 24 of the probe, or as a result of strain in the stylus 24; as an alternative, measurements may be made only on the basis of strain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.