GB290315A - Improvements in cinematographic apparatus - Google Patents

Abstract

290,315. Oehmichen, E. Dec. 9, 1926. Kinematograph apparatus. -In apparatus having means for pressing the film in the gate into a flat position during its stationary periods, means are provided for producing a slight pressure on the film during the feeding periods, or during the final portions of such periods, so as to prevent loss of contact between the feed teeth and the film perforations. As shown in Fig. 1, a rigid transparent plate 3 or other pressure member is intermittently pressed against the film in the gate during its stationary periods by a spring 4 under the control of a cam 5 and linked levers 6, '7. A second pressure member 9 exercises a slight constant pressure on the film, and the pressure may be adjustable. Fig. 2 shows a construction in which one pressure member 3 is provided and is acted upon constantly by springs 10 and intermittently by a spring 4. Fig. 4 shows a single pressure member 3 which is engaged by rod 8 carrying a spring 4 extending between a disc 13 formed on it and a sleeve 12 slidably carried by it. The sleeve 12 is controlled by a cam 5 which is shaped so as to cause the sleeve to engage a pin 14 and move the rod from the member 3 during feed movements, so as to produce a slight pressure at the end of the feed movements, and so as to produce a greater pressure during the stationary periods. A modification is described in which a single pressure member is operated by a cam and levers, either through a cushion of elastic material, or directly, the system being elastic. The pressure members &c. may be carried by a movable gate member which may be substituted for an existing gate. As shown in Fig. 5, the intermittently acting pressure members have push rods 8 acted upon by springs 4 which may be lifted by levers 4a engaged by tappets 21 on the hinge pin 16 of the gate. The pin 16 is rocked by a pin 20, lever 6, and cam 18 on a shaft 17 driven by the projector, the arrangement being such that the gate may be freely opened or closed. Modifications are described in which the hinge pin is continuously rotated by bevel gearing, and in v.hich the pressure members are controlled by a longitudinal sliding rod, the rod being carried by the movable gate member or by the body of the projector.