Weighing scale with EMI/RFI shielding

摘要

An electronic weighing device includes a lower electrically conductive plate, an upper electrically conductive plate, a load cell coupled to central portions of the upper and lower plates such that the load cell responds to weight on the upper plate, and a flexible, conductive band coupling the periphery of the upper plate to the periphery of the lower plate. An electronic circuit is coupled to the load cell. The circuit is provided on a board which is mounted on the lower plate close to its center. A pair of bores are provided in the lower plate extending from the circuit board to an edge of the lower plate. A pair of non-conductive rods are coupled to potentiometer on the circuit board. The non-conductive rods extend through the bores from the circuit board to the peripheral edge of the lower plate. The lower plate is provided with a shielded electrical socket which is coupled by shielded cable to the circuit board. A conductive cover is provided over the upper plate, the load cell, and the band. The weighing device provides a conductive envelope which substantially encloses the load cell and associated circuitry. Preferably the band is formed with metallic cloth tape which is applied to the edges of the upper and lower plates in a sideways- OMEGA -shaped configuration. The band does not interfere with the movement of the plates, yet provides an RF/EM shield around the space between the plates.