Brake point film metering
US5655169A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 1995 |
| Grant date | Aug 5, 1997 |
| Priority date | — |
| Expiry date | Jun 1, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B1/60
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Film winding between exposures in a photographic camera is interrupted and/or braked as a function of film velocity. The camera uses velocity in a control mechanism that stops the winding motor as a function of the velocity in response to detection of a film perforation. The function acts on a time interval between sensing a perforation and stopping the motor or applying a brake. The perforation detector and the velocity sensor use a single sensing element that generates first and second signals at the respective leading and trailing edges of a perforation. The time interval between the first and second signals is indicative of film velocity, and is used to determine the stopping function preferably in accordance with a predetermined look-up table. The control then selects an appropriate time interval between sensing a respective one of the perforations and stopping said motor. A brake also may be applied for stopping film movement, and the control applies the brake as a function of the velocity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.