A Simplified Method of Conversion of Standard Intermittent Motion-Picture Projectors for Use with Television Pickup Tubes

A 35mm Simplex projection head was converted for use as a television projector with the 3:2 field-sequence method of utilizing film taken at the rate of 24 frames/sec for the 30-frames/sec television standard. A 35% application time is obtainable with a 5-in.-diameter shutter blade running at 3600 rpm. The entire mechanism, including the feed and holdback sprockets, shutter and intermittent Geneva, is driven from a single 1800-rpm synchronous motor. A timing belt drive is used for the intermittent mechanism. An eccentric toothed idler pulley of twice the diameter of the Geneva drive pulley is interposed between the motor and the Geneva drive to produce the required advance and retard modification of the rotary motion. The timing and change of acceleration are illustrated by curves. This method of conversion offers the advantages of simplicity and economy. Very little added noise or acceleration loading is produced and long operating life may be expected.

Print ISSN

0361-4573

Published

1960-02

Content type

Original Research

DOI

10.5594/J14417