View finder for photographic apparatus utilizing objectives having different focal lengths
US4038673A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 20, 1976 |
| Grant date | Jul 26, 1977 |
| Priority date | — |
| Expiry date | Aug 20, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B13/12
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A view finder for use in photographic apparatus which embody or are connectable with two objectives having different focal lengths has a field lens, an eye lens behind the field lens, and two intermediate lenses each of which is pivotable in the housing about a fixed axis between an operative position in which it extends across the path of scene light between the eye lens and the field lens and a retracted position. A link is articulately connected to both intermediate lenses whereby the connection between the link and one of the intermediate lenses constitutes a pin-and-slot connection. A second pin-and-slot connection attaches the link to one arm of a two-armed lever which is pivotably mounted in the housing and the other arm of the lever is coupled to a reciprocable slide by a third pin-and-slot connection. When the slide is moved in one direction, one of the intermediate lenses is retracted and the other lens moves to operative position. The movements of the intermediate lenses are reversed when the slide is moved in the other direction. A prestressed looped spring engages the connections between the link and the intermediate lenses to yieldably urge either intermediate lens to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.