Apparatus for measuring thickness differences in record carriers, such as bank notes and the like

Abstract

The apparatus comprises a roll, having an elastic surface, mounted for rotation about a fixed axis with the elastic surface arranged to engage one surface of a record carrier. A piezoelectric transducer is mounted perpendicular to the axis of the roll and rigidly with respect to the roll, and a sensor is mounted quasi-rigidly, with respect to the transducer, between the roll and the transducer, the sensor being fixedly joined to the transducer. In the quiescent condition, without a record carrier being passed between the sensor and the roll, the distance from the roll surface to the sensor is smaller than the smallest paper thickness to be measured. The transducer is mounted in a holder having a spring member fixedly joining the sensor to the transducer. The sensor may include a sensing roll or may be designed as a sensing runner with a sharp edge, and an elastic damping plate connects the transducer to the sensor.

Dependencies are inferred from the claim text.