Scale with weight-to-period transducer
US4239088A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 8, 1979 |
| Grant date | Dec 16, 1980 |
| Priority date | — |
| Expiry date | Jan 8, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01G23/3707
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A postage scale includes a directly loaded weight-to-period transducer which provides an oscillating output, the period of which varies as a function of the weight to be measured. The transducer includes a disc of piezoelectrically active material bonded to an inactive substrate base which dishes at its center in response to the weight to be measured. The transducer frequency output is processed to provide a digital period signal. A reference oscillator having matched temperature characteristics generates a high frequency count calibrated for scaling the transducer period to a weight count. The high frequency signal and the period signal are gated to provide an input to a counter which generates a digital weight information signal. The weight information signal is transmitted to a mailing system processor for use in determining the postage requisite for mailing the article.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.