Patent GB-280161-A (GB)
Title: Cinematographic apparatus for the projection of moving pictures
IPC: G03B21/02
Filed: 1927-03-18
Abstract: 280,161. Bogopolsky, J. Nov. 2, 1926, [Convention date]. Kinematograph apparatus.-In a projector, the gate is formed of two members which may be arranged so as to be suitable for films of two different widths, and the intermittent feed mechanism is constructed so as to be suitable for marginal or central film perforations, and is influenced by the gate so that the appropriate feed members become operative. As shown, the apparatus comprises a compartment 2 containing a driving motor 3 and fans 69, 70 for circulating cooling air, a compartment 4 containing intermitmittent feed mechanism, shutters, and a clutch, a compartment 7 containing worm gearing 8, a space 12 containing variable lamp resistances 13, and a compartment 15 containing a lamp 16 and condenser 17. The mechanism is operated from a central shaft 11 driven from the motor 3 by a belt passing round a pulley 5, the pulley being loose on the shaft and carrying a dog 34 which may engage a dog 35 on an axially-movable spring- pressed member 6 secured to the shaft. The pulley 5 serves as an intermittent shutter, and a second shutter 73 may be driven directly by the motor to reduce scintillation during still projection; either or both shutters may serve as fans to cool the film in the gate. The shutter 73 may be replaced by a transparent shutter held stationary in the beam during still projection to cut off heat. The dogs 34, 35 may be disengaged by means of a lever 36 engaging the member 6, and the lever may be operated by a second lever 38, Fig. 5, pivoted at 39. One end 41 of the lever 38 engages the edge of the film, and, when it drops into a recess therein, the opposite end 32<a> engages a pin 40 on the lever 36 to turn the lever into operative position and stop the mechanism. The shaft 11 carries a worm 10 driving a worm wheel 8 on a shaft 55 carrying a sprocket 42 over which the film 47 passes both towards and away from the gate. The shaft 55 also drives, through friction cultches, belt pulleys 46, 54 carried thereon and respectively driving the upper and lower film spools; one-way driving connections are provided between the driven pulleys and the spools so that the spools are alternatively driven for winding or rewinding. The intermittent feed mechanism is operated by a cam 21 on the shaft 11 which raises and lowers a carriage 20 by means of flanges 22, and by a cam 31 which presses a claw carrier 23 towards the film about its pivot axis 24 and against the action of a spring 25. The carrier 23 has marginal claws 27, 28 and a central yieldingly mounted claw 29. The gate comprises members 48, 49, of which the member 49 is vertically movable to bring a large or a small film aperture into the optical axis; the members are shaped so that the vertical movement also causes them to separate or approach one another and form film channels respectively suitable for wide or narrow films. When the member 49 is in the upper position, the marginal claws 27, 28 operate through slots to feed the film and the central claw moves over the surface of the member; when the member 49 is in the lower position, the central claw projects through a slot in the member to feed the film. Vertical movements of the member 49 may be effected by a roller 94, and such movement serves also to adjust the masking. The member 49 is resiliently mounted on the lamp house 15, and the lamp house is movable on rails 75, 76 to facilitate film threading. Means for braking or reversing the motor, for breaking the lamp circuit, for varying the strolie of the feed claws, and for guiding a narrow film are described. The three feed claws may be replaced by one laterally movable claw.