Synchronisation of two moving elements

Abstract

Abstract 708,162. Photo-electric control systems. MATERIEL ELECTRIQUE S. W. May 13, 1952 [June 12, 1951], No. 12109/52. Class 40 (3). [Also in Group XXXV] To detect the amount and direction of the lack of alignment between e g. a printing drum 1 and a web 2, the drum is provided with a principal reference mark 3 and five auxiliary marks either side, and the web with a reference mark 12. The marks are detected by photocells 8, 17 which supply pulses 11 to a counter 20, through a gating circuit 11 which blocks all pulses from the drum until the arrival of a pulse from the web circuit. If the web lags on the drum more than six pulses will be counted, if the web leads, less than six. The counter operates a correcting device to vary the relative position of the paper and drum. In one alternative arrangement a vernier scale may be used, Fig. 3, not shown, the web being provided with twelve marks along an equivalent length to eleven on the drum, and the gating circuit is arranged to block until coincident pulses are received from the web and drum. In a further arrangement, Fig. 4 (not shown) the pulses from the drum may be fed into a pair of gating circuits 25, 27 which block the pulses respectively after and before the arrival of the web-pulse. The separate outputs are fed to "stepped" circuit integrators 30, 31, and the number may be indicated by voltmeters 32, 33. The difference in voltage between the two circuits may be fed to a visual indicator 34 and a correcting circuit.

Inventors

No inventors recorded.

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