Signal processing circuit for trigger probe
US5671542A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 4, 1996 |
| Grant date | Sep 30, 1997 |
| Priority date | — |
| Expiry date | Jan 4, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interface circuit for processing signals from a touch trigger probe is adapted to prevent the generation of false trigger signals during an inspection cycle. The probe incorporates a plurality of strain gauges, the voltage across which rises above a predetermined threshold when a stylus supported by the probe contacts a surface. When the probe is moved away from the surface and the stylus loses contact, the outputs across the gauges drop below the trigger threshold. The interface prevents false triggers When, while the stylus is in contact with a surface, a machine vibration occurs which causes an oscillation in the voltage across the gauges; the voltage dropping below the threshold level (causing the interface to reset), and then immediately passing back up through the threshold, causing the interface to emit a trigger signal. The interface of the present invention prevents such an occurrence by returning to its seated level only if, at a predetermined time interval after the sensor signal has passed below the predetermined threshold, the signal level from the or each sensor has not once again exceeded the predetermined threshold value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.