Photography – With film drive – Mechanical detail
Reexamination Certificate
1999-02-12
2001-01-23
Gray, David M. (Department: 2851)
Photography
With film drive
Mechanical detail
C396S413000
Reexamination Certificate
active
06176625
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a camera, and to a method of loading a camera.
In recent years cameras known variously as disposable or single-use cameras, or referred to by some as lens-fitted photographic film packages, have become increasingly popular. These are cameras of simple construction which are pre-loaded with film by the manufacturer. Once the user finishes the film, the user returns the entire camera to the photolab for developing of the film. The manufacturer may then either discard the camera in its entirety, or subject to appropriate checks that the camera is still functional, re-load the camera. Alternatively the manufacturer may re-use specific components of the camera.
As the awareness of problems of environmental contamination increases, as well as for economic reasons, consumers are less willing to tolerate disposable products. There consequently exists a need for a very simple and cheap camera and yet which can be re-used at least several times by a user.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a camera having a film-cassette chamber for receiving a film cassette having a spool therein on which film is wound and a film receiving chamber, the camera further comprising a film advance wheel including means for engaging the film cassette to allow film to be wound into the cassette; a rotatable spool disposed in said film receiving chamber to which a leading end of the film can be attached; a film pre-wind wheel connected to the spool, at least a portion of said pre-wind wheel being accessible externally of the camera by a user; and means for selectively ensuring unidirectional rotation of the film advance wheel during film advance after each exposure, said means being selectively disengageable to allow free rotation of the film advance wheel.
The ability to disengage the film advance wheel allows the user to withdraw the film from the cassette themselves, and thereby reload the camera.
Preferably, the camera further comprises means for selectively engaging means on said rotatable film take-up spool to ensure unidirectional rotation of said spool during a film pre-wind operation. This assists the user in the pre-wind operation, ensuring the film is wound on to the spool in the right direction, and does not loosen if the user stops unwinding the film.
In a preferred embodiment the means for selectively ensuring unidirectional rotation of the film advance wheel comprises a ratchet pawl selectively movable into engagement with the film advance wheel. The ratchet pawl is biased in a direction into engagement with said film advance wheel, and movable actuating means are provided to disengage the ratchet pawl from the film advance wheel. The movable actuating means comprise a slidable arm which acts on a portion of said pawl to push it out of engagement with said film advance wheel. The slidable arm is provided with a portion thereof adapted to engage in one or other of a pair of detents which thereby define the engaged and disengaged positions of the slide arm and ratchet pawl.
Preferably, the means to selectively engage said rotatable take-up spool comprise a second ratchet means, and said means on said rotatable film take-up spool comprise the pre-wind wheel which is provided with a plurality of teeth. The second ratchet means includes a springy slide arm movable into engagement with said pre-wind wheel to allow rotation of the wheel in one direction only. The springy slide arm is provided with a portion thereof adapted to engage in one or other of a pair of detents to thereby define the engaged and disengaged positions of the springy slide arm.
The means for selectively engaging means on said rotatable take-up spool may alternatively be operatively connected to said means for selectively ensuring unidirectional rotation of the film advance wheel. This allows the user to effect disengagement/engagement of both film advance and pre-wind wheels by operating a single switch. Preferably, the means for selectively engaging means provided on said rotatable take-up spool comprise a second ratchet pawl, and the means provided on the rotatable take-up spool comprise the pre-wind wheel which is provided with a plurality of teeth. The second ratchet pawl is biased by resilient means into engagement with said further wheel.
The camera preferably includes a removable rear cover which includes a latch to releasably secure the rear cover to the camera. Alternatively, the camera may include a hinged back portion which may be opened to allow for reloading.
The camera may also be of the type adapted for use with film carrying pre-exposed latent images, as for example discussed in U.S. Pat. No. 5,187,512 of Polaroid. In this case, the camera includes masking means for masking a portion of said exposure window.
According to a further aspect the invention resides in a method of loading a film into a camera comprising a film cassette chamber and a film take-up spool housed in a film receiving chamber, a film advance wheel including means for engaging a spool of the film cassette to allow film to be wound into the cassette, a film pre-wind wheel connected to the film take-up spool at least a portion of which is accessible by a user, and means for selectively ensuring unidirectional rotation of the film advance wheel the method involving the steps of: (a) inserting the film cassette into the cassette chamber and attaching a leading end of the film to the film take-up spool; (b) disengaging said means for selectively ensuring unidirectional rotation of the film advance wheel, and engaging the means for selectively ensuring unidirectional rotation of the film take-up spool; and (c) rotating said film pre-wind to unwind the film from said cassette on to said take-up spool.
This method may be carried out by the manufacturer or user, and if carried out economical out in a dark environment it is unnecessary to close the camera back. The method may be carried out by the user on re-loading in which case the method would usually be carried out with the winding occurring after the back of the camera has been fitted.
Preferably, the camera has means for selectively ensuring unidirectional rotation of the film take-up spool, wherein step (b) of the method further involves engaging the means for selectively ensuring unidirectional rotation of the film take-up spool. After step (c), the method preferably requires the step of (d) engaging said means for selectively ensuring unidirectional rotation of the film advance wheel, and disengaging said means for selectively ensuring unidirectional rotation of the film take-up spool.
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patent: 5452033 (1995-09-01), Balling et al.
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patent: 5576789 (1996-11-01), Patton
patent: 5689733 (1997-11-01), Zawodny et al.
patent: 5758198 (1998-05-01), Watkins et al.
patent: 5778269 (1998-07-01), Williams
patent: 0750214 (1996-12-01), None
patent: 557664 (1943-11-01), None
patent: 563884 (1944-09-01), None
patent: 708506 (1954-05-01), None
Gray David M.
Samuels Gauthier & Stevens
LandOfFree
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