Patent GB-271923-A (GB)
Title: Improvements in or relating to kinematograph and optical projection apparatus
IPC: G03B21/32
Filed: 1926-01-28
Abstract: 271,923. Thornton, J. E. Jan. 28, 1926. Kinematograph apparatus. - A kinematograph or other projector for use with a separate spoolcase containing a feed-drum, a supply spool, and a take-up reel, comprises a driven crown wheel which engages a similar crown wheel carried by the feeddrum; spindles engaging the spools, and hand-adjusted mechanism for alternatively driving the spools may also be provided. As shown in Figs. 4 and 5, the projector comprises a frame A carrying an enclosed gear case B and having a hinged lid A<1> which, when closed, presses the film holder E downwards against the action of springs N. Four fingers O on rods o, rotatable by a, handle O<1> and a crank disc linked to the rods, may be provided to enable the spoolcase to be raised out of operative connection with the projector mechanism. The spoolcase is constructed as described in Specification 271,922, and comprises a feed-drum E<1>, a supply spool F<2>. and a take-up reel F<3>. The drum E' is formed with crown teeth e which engage crown teeth d<4> on a sleeve D<3> running on a ball race d<5>. A geneva wheel D<1> engaged by a pin f on a locking wheel G may be provided to rotate the sleeve D<3> intermittently, or toothed gearing may be provided to rotate the sleeve D<4> uniformly. The shaft g of the wheel G is driven through screw gears g<1>, g<2>, a shaft G', clutch G<2>, and worm gear h<1>, by a motor H. Alternatively, it may be driven directly by a detachable handle M through bevel gearing m'. when single images are to be projected for a prolonged time, the clutch G<2> being then disengaged. The take-up reel F<3> is driven during projection by a spindle K having crown teeth engaging similar teeth in a hole in the reel hub, the spindle K being provided with a metal or fibre disc wheel k engaged by a similar wheel L<4> on a stud L' driven through gears L, k<2> from the shaft G<1>. The supply spool F<2> may be similarly driven, but at a greater speed, when the film is to be rewound, by crown teeth and disc wheels ;, L<5>, the stud L<1> being carried by an arm L<2> which may be swung over so that a disc wheel L<3> engages the wheel L<5> and the wheel L<4> disengages the wheel k. A clutch may be inserted between the wheels G, g<1> so that the drive for the drum E' may be disconnected during rewinding. A drum shutter S having one or three blades, and rotated at three or one revolution respectively per picture shift, mav be provided within the sleeve D<3>, and may be driven by gearing s from the shaft g; alternatively it may surround the lens P or may be replaced by a disc or fan shutter between the film and lens. Mica windows may be provided in the shutter openings to cut off the heat in the light beam, or an auxiliary shutter of known type may be provided for this purpose. The lamp P<1>, a condenser P<3>, and a concave reflector, may be adjustably arranged in the sleeve D<3>, and the lamp chamber may be cooled by a suction fan drawing air therefrom. the fan being combined with the drum S or being otherwise driven. The lamp may be of high or low voltage, and may be supplied from the house mains, through an adjustable resistance in the base of the apparatus, or by storage batteries or a dvnamo coupled to the motor. Figs. 16 and 18 show in plan and end elevation a construction of the apparatus in which the spoolcase E is arranged vertically in a cage B<4> movable' laterally on rods b<1> by a rack and pinion b<2> or by toggle links, to bring it into operative engagement with the projector. The film may be illuminated by a lamp P<1> &c. and a reflector P<4> within the feed-drum. The relative positions of the lamp and lens P may be reversed, and the light source may consist of an electric lamp or an inverted incandescent mantle having a parabolic reflector above it to direct light downwards on to a curved reflector directing it through a condenser on to the film. Specification 164,467 is referred to.