GB1478841A - Film transport system - Google Patents

Abstract

1478841 Film transport systems R FIELD K VINCENT and H NADIG 20 June 1974 [20 March 1973 21 June 1973] 13410/73 and 29470/73 Heading G2E A film transport system accurately positions frames of a film strip at a gate aperture by comparing the actual position, as detected by a sensor, with a pre-programmed position, generating an error signal to correct the motion of the motor shaft driving the film. The sensor may detect the location of a perforation edge, or coded marks along the film strip. Alternatively an encoder may be attached to the driving motor shaft, whose angular position is detected by the sensor. The sensors read the precise position in the film gate, which reading is fed back to a central electronic network which compares that position with a preprogrammed velocity/position curve. The position or velocity of the film frame is thus continually corrected. The shutter comprises a segmented disc (7), Figs. 1 and 2 (not shown), and it may be controlled electronically in a manner identical to the film drive. Both the film drive and shutter drive are controlled and co-ordinated by a central timing circuit, as shown in the block diagram of Fig. 3. The description is amplified in some detail in the two Provisional Specifications.