Measuring arrangement in a device for automatic unit sprue genuine of at least partially in the table - or copper pass pressure produced documents, in particular bank notes

摘要

1,235,383. Testing banknotes. SODECO SOC. DES COMPTEURS DE GENEVE. 17 June, 1968 [15 June, 1967], No. 28751/68. Heading G4X. Apparatus for testing the authenticity of banknotes includes a differential transformer TA having a feeler A attached to a movable core K for moving over the surface of a banknote, the output of the differential transformer being applied to a null circuit N and after being amplified and rectified, to a logic circuit LS generating an acceptance or non-acceptance signal. In a modification, Fig. 2, the rectified signal Vi is applied to threshold units T3, T4, whereby a non-acceptance signal is generated if the signal Vi moves below or above predetermined limits, and the differentiated signal Vd applied to threshold units T1, T2 feeding counters Z1, Z2 and a logic unit E, whereby a non-acceptance signal is generated if the number of times the signal Vd moves above or below predetermined limits does not fall within preset limits. In another embodiment, the signal Vi is applied to a unit for comparison with a signal generated by a standard banknote. The second signal may be pre-recorded or generated by a second differential transformer.