Optics: motion pictures – Shutters
Reexamination Certificate
1999-07-09
2001-07-10
Adams, Russell (Department: 2851)
Optics: motion pictures
Shutters
C352S159000, C352S166000, C352S184000
Reexamination Certificate
active
06257725
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to motion picture film projectors, and more particularly to a shutter assembly for carrying a film shutter into and out of alignment with a motion film projector aperture block.
2. Description of the Background Art
Motion picture film generally consists of a succession of still images or frames, which are sequentially projected onto a surface to produce the illusion of motion. Motion film projectors are, therefore, configured to transport each frame from a feed reel or spool to an aperture block, where the frame is held in stationary register for a period of time required for projection of the associated image. The frame is thereafter transported to a take-up. reel or spool. Similarly, a motion film camera is configured to transport each unexposed frame from a first location to the aperture block, where the frame is held in stationary register during exposure of the frame, and thereafter to a second location in the camera.
One motion film projector design is described in U.S. patent application Ser. No. 09/193,373, entitled System and Method for Transporting Film and Motion Film Projector Utilizing Same, filed Nov. 17, 1998. This design includes a plurality of shutters disposed on a moving linear conveyor for selectively shuttering a projector aperture block and for transporting the film across the aperture block. In one embodiment, the linear conveyor is a timing belt driven by toothed conveyor sprockets, which advance the shutters into and out of alignment with the aperture block at high speeds (48 shutters per second).
A need exists to provide a system and method by which a shutter may be reliably and securely mounted on a film projector conveyor such that the shutter is substantially stable. Moreover, a need exists to provide a shutter assembly that is adapted to carry a shutter over both straight and arcuate portions of a shutter travel path. An additional need exists for a shutter truck assembly that permits a shutter to be securely mounted on a toothed conveyor.
SUMMARY OF THE INVENTION
The present invention overcomes or substantially alleviates prior problems associated with motion film projectors and prior systems and methods for coupling a shutter to a conveyor. In general, the present invention provides a shutter assembly that includes a shutter disposed on a mounting bracket, which houses multiple trucks for guiding the shutter through a projector raceway. Preferably, the mounting bracket slidably houses one of the trucks to accommodate for the trucks passing over straight and curved portions of the truck path.
According to one embodiment, the shutter assembly includes a shutter securely mounted on a mounting bracket. The mounting bracket fixedly houses a first truck and slidably houses a second truck. The trucks are rigidly clamped to the conveyor. This configuration permits the shutter to be stably coupled to the conveyor while permitting the shutter assembly to travel along both straight and curved paths by permitting the second truck to slide relative to the mounting bracket as the mounting bracket passes between straight and curved paths.
The shutters are preferably of two general types: primary shutters and secondary shutters. The primary shutters are also referred to as film carriages, because they serve the dual functions of shuttering the film, and also transporting film loops into and out of alignment with a projector aperture block. The secondary shutters preferably include a flat, vertically-oriented, plate for supporting the film and for shuttering frames of the film.
The trucks are generally configured to ride in a raceway, which supports the trucks and maintains, or guides, the trucks along a predetermined truck path. In one embodiment, the trucks include rollers, which roll along an elongated channel formed in the raceway. According to another embodiment, the trucks include air bearings for carrying the truck along a pressurized air raceway.
Further, the trucks preferably include a groove that is sized to receive one of the teeth of the toothed conveyor. In this configuration, the truck may be secured to the toothed conveyor by positioning a conveyor tooth within the groove and then clamping the conveyor to the truck. Maintaining the conveyor tooth within the truck groove helps prevent the truck from moving relative to the belt.
In one embodiment, the shutter assembly path may be generally characterized as having top and bottom portions that are substantially straight, or linear, and side portions that are curved, or semicircular in shape. Because the shutter assembly passes along both straight and semicircular paths, the distance between the trucks rigidly mounted to the belt varies as the shutter assembly passes from a straight portion to a semicircular portion and vice versa. To accommodate for this variance in truck separation distance, the mounting bracket slidably houses one of the trucks so that the slidably housed truck may move relative to the other truck as the shutter assembly moves between straight and semicircular portions.
Additional advantages and features of the invention will be apparent from the drawings and detailed description as set forth below.
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Adams Russell
Advanced Image Systems, Inc.
Carr & Ferrell LLP
Fuller Rodney
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