A Two-Speed Drive for Continuous Motion-Picture Printers

John J. Graham, Howard F. Ott

In this two-speed drive, adapted to a Bell & Howell Printer, Model D, two motors running continuously drive the fields of two electric clutches in the same direction, one at approximately twice the speed of the other. The armatures of the clutches are on the same shaft and are splined to the hub of a third pulley that drives the printer. An electrical circuit triggered by a cuing system activates one clutch or the other to change the speed of the printer within a short enough interval so that there is no loss in projection quality of the print. Such a speed changer permits optimum productivity on a printer using negatives containing scenes of widely varying densities.

Print ISSN
Published
1959-01
Content type
Original Research
DOI
10.5594/J13854