Patent GB-934503-A (GB)
Title: Apparatus for the selection and projection of a film
IPC: G07F17/16
Filed: 1960-06-27
Abstract: 934,503. Multiple-film projection apparatus. MOVIESBOX GENERAL SYSTEM S.r.1. June 27, 1960 [June 27, 1959; Feb. 9, 1960], No. 22524/60. Class 97 (1). An apparatus for the selective projection of one of a plurality of films comprises, within a casing, a mobile magazine unit carrying a plurality of projection elements each of which contains a removable film, sound head and a known film-feed system couplable with an external drive and, in response to a manual selection operation, can be positioned in alignment with a fixed optical projection system including a light source, in which position it is engaged by a locating element and also by the driving shaft of an electric motor, the engaging movement of these latter being initiated by the coming to rest of the magazine unit, the light source and driving mechanism and sound reproducing devices then becoming energized to back-project the film on to a viewing screen integral with the apparatus. As shown in Fig. 1, an array of projection elements 3 is carried on an endless chain 5 (Fig. 2) looped over two wheels 7, 6, the latter being rotatably driven via its spindle 6<SP>1</SP> and belt 11 from motor 8. The projection elements 3 are detachably fixed to the chain 5 by a dovetail coupling 4 and are formed as a pair of mating boxes 20 (Fig. 3) and 20<SP>1</SP> (Fig. 4). Box 20 contains a drive shaft 17, couplable at 17<SP>1</SP> to the conical extremity 12 of the shaft of a motor 13, the shaft 17 meshing via worms 21, 22 with helically geared wheels 23 and 24, the latter being connected with a Maltese cross mechanism 26<SP>1</SP>, the spindle 39 of which extends into the box 20<SP>1</SP> to operate a film feed sprocket 38 geared with a shutter 40. The spindle 26 of wheel 23 also extends into box 20<SP>1</SP> where it drives, via wheel 27, a main feed sprocket 29 to which film spools 30, 30<SP>1</SP> are linked via belts and pulleys. Pins 32, 35 which are rigid with pulleys 31, 34 respectively extend into box 20 where pin 32, via worms 43, 45 and helically geared wheels 44, 46, drives wheel 47 to which is secured one end of a coil spring 48, the other end being secured to a fixed part of the projection element, whereby spring 48 becomes tensioned during projection of the film as the latter runs off spool 30 in the direction shown so that when projection has been completed and the drive disconnected the film is rewound by the spring tension, the stop 49 on wheel 47 engaging a notch to arrest the rewind at a predetermined position. When the selected projection element 3 arrives in the projection position (Fig. 2) electromagnet 16 becomes energized pivoting lever 14 in the direction F whereby a conical locating stem 18 and the drive shaft 12 of a motor 13 carried on the lever enter, respectively, a recess 19 in the projection element housing and a recess in the drive shaft 17 of the projection element mechanism. A mirror 52 reflects into the element light coming from a lamp 50 (cooled by fan V) via condenser 31 and after passing through the shutter 40 and the film leaves through aperture 53 and is focused by the fixed projection lens 55 (see Fig. 1) via mirrors 56 on screen 54. A sound head 57 is provided in each projection element. In an alternative embodiment the projectionelement-carrying chain is carried by only one wheel, and the film in each projection element is held by four resilient tensioning spools in a single open reel unwound from its innermost turn and rewound on the outside of the reel. The other mechanical and optical details are varied but equivalent.