LVDT displacement sensor with signal noise reduction for use in weighing apparatus
US4916391A · kind A · utility
Inventors
Key dates
| Filing date | Mar 21, 1989 |
| Grant date | Apr 10, 1990 |
| Priority date | — |
| Expiry date | Mar 21, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01G9/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
To weigh objects in quick succession, the objects are projected with a known horizontal velocity onto a ramp which has a surface which curves down through 90.degree.. The ramp can move horizontally in response to the impulse corresponding to the change in horizontal momentum of the object. A transducer senses the movement of the ramp and the output horizontal velocity of the object is sensed, enabling the change in horizontal velocity to be calculated. The mass of the object is calculated from the horizontal movement of the ramp and the change in horizontal velocity of the object. In order to obtain accurate sensing of the movement of the ramp, the transducer is a linear variable differential transformer having a primary winding energized by a cyclical carrier signal and two matched secondary windings in series; the secondary winding output signal is rectified to a corresponding DC voltage having ripple components, and a sample is taken of the signal at the zero voltage of the principal ripple component.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.