Quietly operating anti-backup pawl for manual film advance thumbwheel in camera
US5748988A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 1997 |
| Grant date | May 5, 1998 |
| Priority date | — |
| Expiry date | Mar 13, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B2219/045
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A camera comprising a rear cover part having a rear opening, a rotatable film advance thumbwheel protruding from the rear opening to permit the thumbwheel to be manually rotated in a film winding direction and having a continuous alternating series of teeth and spaces, and a flexible beam projecting from the rear cover part and having an anti-backup pawl to be received in anyone of the spaces to prevent reverse rotation of the thumbwheel but being pushed out of anyone of the spaces to make the beam flex away from the thumbwheel when the thumbwheel is rotated in the film winding direction, is characterized in that the beam has a pair of opposite ends fixed to the rear cover part and said pawl is located between the fixed opposite ends, to make the beam be flexed intermediate its fixed opposite ends when the pawl is pushed out of anyone of the spaces because of manual rotation of the thumbwheel in the film winding direction, whereby the natural frequency of vibration of the beam can be raised to make the noise of the pawl contacting successive ones of the teeth when the thumbwheel is rotated in the film winding direction less noticeable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.