Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Patent
1997-04-28
1999-02-16
Darling, John P.
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
352156, G11B 23093
Patent
active
058711678
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to movie film cassettes, and more particularly to an expendable cassette designed to receive an unexposed film reel and to store the exposed film until development. The invention more particularly relates to movie films, for example, 16-mm or 35-mm films.
Such films are conventionally included in a magazine associated with a movie camera. The unexposed film is unrolled in front of a shutter from a supply reel engaged about a shaft of a supply compartment through a driving mechanism. The exposed film is wound on a collection reel engaged about a motor driven shaft of a collection compartment of the magazine. Because of the important length of film that is generally used in this type of movie camera, the supply and collection reels are generally wound coaxially about cores which cooperate with coaxial supply and collection shafts, respectively, linked to the magazine.
A drawback of conventional magazines is that the loading of an unexposed film in the magazine and the collecting of an exposed film require absolute darkness, because an unexposed reel is loaded down flat by engaging a first core, around which the film was rolled during fabrication, on the supply shaft of the magazine. The film leader is then engaged in the driving device of the magazine and fixed to a second empty core engaged on the collection shaft of the magazine. Even though the magazine can be closed as soon as the unexposed film is placed about the supply shaft and the film leader is engaged into a slot provided for this purpose, since the supply compartment is isolated from the rest of the magazine, inserting an unprotected reel into the supply compartment may veil the unexposed film. An exposed film is taken out by opening the collection compartment and extracting the core about which the exposed film reel is wound. The exposed film is taken out in a flat position, as for loading, and is not protected from light.
In order to permit to load or to take out the magazine without exposure to day-light, the optic block of the camera, which includes means for engaging the driving mechanism, is generally separated from the magazine including the driving mechanism. Indeed, 35-mm films, and even 16-mm films, are frequently used to shoot feature-length films which require the use of several film reels. Such films are not necessarily shot in studios and are often far away from a dark room where the loading or unloading of the magazine can be safely achieved. Thus, this operation generally requires the use of several magazines which are preloaded to shoot under acceptable safe conditions for the film reels. However, the driving mechanism of the magazine is a very expensive system because it should be noiseless and be very accurately fabricated. Hence, the need for providing a plurality of magazines is expensive.
In the prior art, movie film cassettes including two coaxial supply and collection reels, respectively, have been devised. U.S. Pat. No. 3,829,203 and U.S. Pat. No. 3,475,089 describe such a cassette. This cassette includes, in addition to the two reels, a back pressure pad for urging a portion of the film which passes in front of an aperture of the cassette and which is designed to face a shutter of an optic block of a camera.
A drawback of such a conventional cassette is that it should contain all the guide pins and rollers for bringing the film from the reels up to the back pressure pad. In particular, since the back pressure pad is included in the cassette, the cassette must have means for driving the film from one reel to the other although they are coaxial. This complicates the fabrication and increases the cost. In addition, the constitution of the cassette needs the film to be in contact with fixed or rotating elements, coupled to the walls of the cassette, which constitutes a source of noise because of the fabrication tolerances relative to a low cost expendable cassette.
A further drawback of such a cassette is that it does not ensure accurate positioning of the film in front of the shutter of the opt
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Aaton
Darling John P.
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