Patent GB-865348-A (GB)
Title: Machine for projecting cinematograph films
IPC: G07F17/16
Filed: 1958-12-15
Abstract: 865,348. Photo-electric control systems. DESSILANI, T. Dec. 15, 1958 [Feb. 27, 1958], No. 40337/58. Class 40(3) [Also in Group XX] The parts of a kinematograph projection apparatus concerned with the actual projection and with the film transportation are mounted on two support plates which are movable towards or away from each other; a number of pairs of spools are provided, each pair carrying a separate reel of film, together with means for moving a selected one of these reels into the space between the said plates, so that when the plates are brought together they engage with the film in operative contact. General description. A pair of spools 8, 11 are carried each on the end of respective spokes 7, 10. The film 127 passing from one spool to the other is maintained taut and horizontal by guide rollers 191, 191<SP>1</SP>. Similar pairs of spools 8, 11 are carried at the end of similar spokes which radiate from respective wheels 6 and 9 mounted on a fixed cylinder 4. The wheels can be turned by handle 140, so that any pair of spools may be brought into the upper (operative) position. The film is engaged between two plates 24, 25, shown diagrammatically in Fig. 1 and in more detail in Fig. 4. These plates are spring- loaded towards each other, but can be drawn apart by cords 29, 30 operated by a motor 26. The transport mechanism is mounted largely on the lower plate 24, and is operated by a motor-driven shaft 84. This drives a gear wheel 87 carrying a cam 88 which controls aclaw-feed mechanism 122, 99. Gear wheel engages with a gear wheel 91 carrying a pinion 92, which engages in turn with a sprocket chain 129 which transmits the drive to the actual film-carrying sprockets 101. Each of these is formed as a double sprocket wheel, one part 105 engaging with the chain and the other part 101 with the film. The two parts may be coupled together, as required, by a solenoid-operated cam-driven arrangement (Fig. 7, not shown). The lower plate also carries a member 138 which co-operates with a similar member on the upper plate to form a film gate. The upper plate carries a number of rollers for engaging against the film. The sequence of operations commences with plates 24, 25 in separated position, and is controlled by a series of cams on a motordriven shaft. The sprocket wheels are first uncoupled, so that the film-carrying sprockets 101 can turn independently of the chaincarrying sprockets 105. The motor 26 is then energized so that the plates move towards each other. A pawl 95 engaging with a ratchet wheel 141 moves the chain just sufficiently to retract the claw 99. Rollers 74, 125, 78, 81 on the upper plate engage the film, holding it against the sprocket wheels, and against a sound head 128. The rollers 71 press the film down into a loop on each side of the gate, and then retract again, thus allowing sufficient play for movement of the film by the claw feed. The sprocket wheels 101, 105 are then again coupled, and the driving shaft started, so that the chain now drives the claw feed to transport the film. Finally, the projection lamp 180 and the lamp for a photocell 126 are switched on. A wheel 56 driven by a belt from one of the sprockets 101 engages the rim of the spool 8, turning it in the "winding-on" direction. Termination of operations. This is brought about by a transparent section of the film passing in front of the photoelectric cell 126, which again starts the motor operating the control cams. The driving shaft 84 is stopped, the lamps 126 and 180 switched off, and the sprocket wheels uncoupled. Motor 26 then operates again to move the plates apart. Rotation of handle 140 now brings a new reel of film on a further pair of spools 8, 11 into position between the plates, ready to commence the operational sequence once more. Re-winding. A curved lever 34 carrying a roller 37, and normally spring-loaded away from spool 11, can be moved into contact with the spool by energizing a solenoid 36. A motor 38 then rotates roller 37 against the rim of spool 11 to re-wind the film thereon from spool 8. This rewinding can take place after the pair of spools 8, 11 have been rotated away from the operative position between the plates. During re-winding, the film passes in front of an illuminated photocell 40, until finally a blacked-out section causes the photocell to break the motor circuit and de-energise solenoid 36.