Film transport assembly
US4778093A · kind A · utility
Inventor
Key dates
| Filing date | Apr 13, 1987 |
| Grant date | Oct 18, 1988 |
| Priority date | — |
| Expiry date | Apr 13, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B1/18
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
An improved film transport assembly is provided for intermittently advancing film, without pulldown claws or similar mechanisms for engaging film perforations to obtain intermittent transport, with extended dwell period past the film gate of a camera or projector, particularly such as a motion picture camera or projector adapted for high speed film transport or for handling relatively large film formats. The transport assembly includes film supply and takeup sprockets for constant velocity film transport respectively to and from the film gate, with the film passing over a primary roller and a compensation roller interposed between each sprocket and the film gate. The pairs of primary rollers and compensation rollers are displaced generally sinusoidally and at different cyclic rates to increase the film path length between the supply sprocket and gate while decreasing the film path length between the takeup sprocket and gate, and vice versa, resulting in a net film velocity of zero at the gate for a dwell period of up to 180 degrees, followed by generally sinusoidal transport of the film through a transport period of about 180 degrees to register the next film frame with the gate. L…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.