Film wind-up control apparatus for a camera
US4720721A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1987 |
| Grant date | Jan 19, 1988 |
| Priority date | — |
| Expiry date | Feb 12, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B1/60
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A film wind-up control apparatus of a camera in which a film is transported in zigzag direction passing around at least a guide roller located before an exposure station, is adapted to advance the film a predetermined length of the film when an exposure is made in a predetermined period of time and an extra length in addition to the predetermined length after the predetermined period of time has elapsed, so as to advance that part of the film which was previously positioned around the guide roller, beyond the exposure station. The apparatus is also adapted to indicate the number of possible exposures with one decrement every other occurrence of the extra length of film advance. In this way, film that has become permanently curled around the guide roller never comes to rest in the exposure station; but at the same time, the count of remaining frames is kept accurate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.