Patent GB-272256-A (GB)
Title: Improvements in kinematograph and optical projection apparatus, and spoolcases and films for use therewith
IPC: G03B21/30
Filed: 1925-12-11
Abstract: 272,256. Thornton, J. E. Dec. 11, 1925. Kinematograph apparatus; optical-projection apparatus.-Kinematograph or other projecting apparatus using film strips comprises a detachable supply spool D with or without a spoolcase, a permanently-fixed receiving reel E, and a long blank leader strip E<1>, the strip E' being permanently attached at one end to the reel T, and having, at the other end, a hook or other means for connecting it to the film or to a leader strip f thereon provided with the hook etc.; a second leader strip may be permanently attached to the supply spool and to the film. The leader strips may consist of metal, of a double strip of linen, or of two strips of parchementized paper cemented to a central linen strip, the whole strip being rendered fireproof. The strip secured to the supply spool may have a long slot, or be formed without perforations, so that film movement ceases when the film has been wholly exhibited. The apparatus may be provided with a spring gate and any known form of intermittent-feed mechanism, or, as shown in Fig. 1, with a hollow intermittently-rotated drum K carrying the film in the exposure position and large enough to contain a lamp B, condenser B', and a concave reflector. Alternatively, the drum K<1>, Fig. 9, may be of small diameter, and contain only a prism P to reflect the projection beam through a right angle. The shutter, in such constructions, may comprise a drum M' within the drum K having one or three blades, and being rotated at three or one revolutions respectively per picture shift. The shutter drum may be alternatively arranged round the lens C, or may be replaced by a crank-operated reciprocating blade or by a rotary disc. Mica windows may be provided in the shutter openings to cut off the heat in the light beam, or a centrifugally controlled cut-off shutter may be used. In constructions comprising a feed drum producing curvature of the film at the exhibiting position, a correcting lens c may be provided as described in Specification 272,371. Anv of the lighting and optical arrangements described in Specification 272,371 may be employed, and various constructional embodiments are described and illustrated. The light source may consist of high or low voltage electric lamps, an incandescent gas burner, daylight &c. The lamp house may be cooled by a suction fan N, Fig. 9, in a fan box having inlets n from the lamp house L. Fig. 11 shows a construction of apparatus wherein the spool D and fixed reel E are arranged behind a gate h<1>, and intermittent sprockets h<2> are provided both above and below the gate. The apparatus may be adapted for use with double-width films exhibited by winding first in one direction and then in the other, and the film-carrying parts of the apparatus may, in such case, be movable laterally in relation to the lens by a rack R and pinion r as shown in Fig. 12. A handle d' and one-way clutch d<2> may be provided to enable the film to be rewound on to the spool D. According to the Provisional Specification, double-width films may be provided with a row of perforations in each margin, with a single row down the middle of the film, or with perforations between successive pictures. Specification 272,140 is referred to.