Device for the scanning measurement of the thickness of a continuous sheet based on air cushion sensor heads mounted on thrust pistons operated by the same compressed air which feeds the air cushions

摘要

In-line sensor for sheet thickness capable of travelling from one edge of the sheet to the other comprising two heads on the opposite sides of the sheet separated from it by air cushions of stable thickness. On the upper head there is mounted an inductive sensor of the distance between the heads from which measurement of the sheet thickness is derived. The heads are mounted on pistons which receive a force pressing them towards the sheet from the pressurised air in two appropriate thrust chambers behind fed by the same source of air as feeds the two air cushions. The upper thrust chamber discharges to atmosphere while the lower discharges to the outlet of a pressure regulator in order to balance the force driving the two heads together. IMAGE