Browse Prior Art Database

Reversible Film Transport

IP.com Disclosure Number: IPCOM000081173D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Dennis, RE: AUTHOR

Abstract

A stepping motor, controlled by logic pulses, and synchronized with a film gauge shutter by a "Hall effect" device provides variable frames per second (FPS), in forward and reverse directions, as well as single frame operation of the transport.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 71% of the total text.

Page 1 of 2

Reversible Film Transport

A stepping motor, controlled by logic pulses, and synchronized with a film gauge shutter by a "Hall effect" device provides variable frames per second (FPS), in forward and reverse directions, as well as single frame operation of the transport.

A stepping motor 10 drives a sprocket 12 by a double-sided timing belt 14 through a capstan 16 and a series of idlers 18' and 18''. The sprocket 12 drives a film strip 20. Power for the stepping motor 10 is provided by shutter mechanism through a logic circuit 24. Control pulses are supplied as a second input to the element 24. The control signals determine the direction, and speed with which the sprocket 12 conducts the film strip 20 to be transported.

The shutter mechanism comprises a slotted disc 26 disposed between a light source, not shown, and the film strip 20. The disc 26 is driven constant speed by a motor 28. Light is passed through a slot 31 and the film strip 20 at defined intervals. A series of magnets 3O are attached to the periphery of the disc 26 and pass by a Hall sensor 32 at time intervals, corresponding to the opening of the shutter or when the slots 31 are between the light source and the film strip
20. The sensor 32 generates a pulse to synchronize the shutter with the movement of the stepping motor 10.

Fig. 2 is a timing diagram where the ordinate describes the rotation of the stepping motor 10 in 15 degree increments for stepping speeds of 6, 18 and 24 FPS. The abscissa rep...