Patent GB-921706-A (GB)
Title: Method and apparatus for operating motion picture cameras without exchange of reels
IPC: G03B19/18
Filed: 1959-06-08
Abstract: 921,706. Kinematograph cameras. CONTINA BUREAUXUND RECHENMACHINENFABRIK A.G. June 8, 1959 [June 19, 1958; Oct. 17, 1958; Nov.14, 1958; April 21, 1959], No. 19568/59. Class 97 (1). In order that two longitudinal strips of a film may be successively exposed in a camera without the necessity for lateral adjustment of the optical system or of exchanging spools, the film is fed from one spool to another to expose the first strip and after twisting the film through 180 degrees during the first exposure or rotating the film in its plane through 180 degrees after the first exposure so that the second strip lies in the light path from the optical system, is then re-wound on to the original supply spool. As shown in Fig. 24, the first strip may be exposed by feeding the film through a gate 263 from a spool 266 to a spool 267 and the second strip exposed, after rotating a shaft 265 which carries the spools and the film gate through 180 degrees, by re-winding the film on to the spool 266. Alternatively, the film may be twisted through 180 degrees as at 270 in Fig. 25 in its path to the take-up spool 267 and only the film gate 263 and associated gate rollers 268, 271 rotated. The film may also be given a second 180 degree twist in its path from the supply spool 266 to the roller 268. In a further alternative, Fig. 23, the film may be twisted through 180 degrees between rollers 258, 259 and two film pressure plates 4 and 248 may be carried by semicircular table 256 which, after exposure of the first strip, is rotated through 90 degrees. This arrangement may be further modified by mounting the spools on a circular table rotatable through 90 degrees (Fig. 22, not shown). A more detailed description is given of one embodiment in which the film is twisted through 180 degrees and the spools are mounted on a circular turntable which is rotated througn 180 degrees between the two exposures. In this camera, Fig. 9, the turntable 12 carries the spools 1 and 10 and film pressure plates 4 and 8. For the first exposure the film 2 is fed from spool 1 to the spool 10 which is driven by a sun-wheel 76, Fig. 13, rotated by a gear 86. This sun-wheel has a rim 77, Fig. 14, meshing with a gear 89 engaging a gear 88 on the shaft of reel 10. On its way from spool 1 to spool 10, the film is twisted through 180 degrees by oblique rollers 6 and 7 and so engages under tension a roller 14 carried by a double arm lever 17, 18 which is pivoted at 16. The decrease in tension due to the trailing end of the film leaving the oblique rollers 7 allows the levers 17, 18 to pivot under spring action and so impale the trailing end 19 of the film on pins 20 and 21, Fig. 4, on the film pressure plate 8. At the same time this movement of the levers 17, 18 releases the spring-loaded catch 23 from a fixed stop 25 so that the turntable 12, which has a rim 70 meshing with a spring driven gear 71, Fig. 13, rotates through 180 degrees. This rotation of the turntable 12 brings projections 82 on the axially displaceable hub 79 of sun-wheel 76, Fig. 14, into engagement with openings in a cover plate 84 and so allows displacement of this hub by a coil spring. Such displacement disengages the sun-wheel gear 77 from the gear 89 but engages the sun-wheel gear 78 with the gear 87 driving the shaft 46 of the spool 1. Rotation of the turntable 12 also causes a nose 52 on a collar 53 to retract the originally used film pressure plate 4 and at the end of the rotation to bring the other film pressure plate 8 into operative position relative to the aperture plate 5. Also at the completion of the rotatable movement of the turntable, a pin 68 thereon operates a cam 62 so that pivoted guides 35 and 36 take up positions in which one end of the guide 36 engages a slot 44 in the hub of the spool 1 and prevents further rotation thereof. Feeding movement of the film through the gate by the usual claw feeding mechanism then causes the original trailing end 19 of the film to be guided into the cavity between the hub 33 of spool 1 and the shaft 46 of this spool, Fig. 7. Projections 48 on shaft 46 thereupon engage in the film perforations so that further movement of the film causes the latter to buckle at 47 with result that the guides 35 and 36 are pressed away from slot 44 and the hub 33 of the spool 1 can again be rotated. This rotation of the spool 1 to rewind the film and allow of the exposure of the second film strip is effected by the sun-wheel gear 78 and the gear 87, the spool 10 free wheeling. The film guide roller 9 adjacent the spool 10 may be positively driven by the sun-wheel 76 through a gear on the spool 10 during exposure of the first half of the film and be provided with sprocket teeth which engage the film perforations. A spring-loaded arm rotatable on the shaft of the roller 9 disengages the film from the sprocket teeth, during exposure of the second strip of the film. Modifications are also described in which the film in its path between the oblique rollers 6 and 7 passes through a guide consisting of a plate which is hinged to a base plate and has a snap fastening therewith and in which a spring biased tongue has projections which move to engagement with the supply spool and hold it fast at the end of the first exposure (Figs. 1 and 2, not shown).