Patent GB-381621-A (GB)
Title: Improvements relating to cinematographic cameras and projectors
IPC: G03B19/18
Filed: 1931-07-14
Abstract: 381,621. Kinematograph apparatus. SMITH, W., 109, Queen Anne Avenue, Bromley, Kent. July 14, 1931, No. 20262. [Class 97 (i).] In cameras and projectors wherein reversal of the direction of feed is automatically effected without reversal of the drive, e.g. apparatus of the type described in Specification 319,644, [Class 97 (i), Optical systems &c.], and wherein the lens system is laterally movable and the film has two ranks of images, the motive power for effecting the movements required for reversal is derived from a spring which is wound by the drive shaft and is then disconnected therefrom until after the reversal ; reversal may be controlled by one film edge, and means for arresting the film under the control of the film perforations, and for restarting it by hand, may be provided. As shown in Fig. 5, a driving crank 8 is directly connected to a crown wheel 9 rotating on a fixed axle 29 carrying a spring barrel 12 and an eccentric 18. The barrel 12 is provided with a lug 17 which is engaged by a projection 16 within the crown wheel to rotate the barrel and wind its spring 13 ; the inner end of the spring 13 is connected to the sheave 18 of the eccentric, and the barrel and sheave have helical meeting surfaces 27, kept in engagement by a spring 28, so that the barrel, as it is rotated, moves along the axle 29 and causes disengagement of the lug 17 and projection 16 when the spring is fully wound, the barrel being then held by a pawl carried by the crown wheel and engaging teeth 14 on the barrel. The sheave 18 carries an arm 22 and is normally held by engagement of the arm with either of two stops 23, 24 on spring-influenced levers 30 carrying rollers 31 engaging a film edge. Recessed parts of the film edge near its ends permit rotation of the levers and release the arm 22 so that the sheave rotates. The strap 19 of the eccentric forms part of a forked lever 20 which rocks about a pin 21 when the sheave rotates ; the lever 20 controls a claw-feed mechanism through a rod 41, and a lug on the strap controls through linkwork, the spool drives, and the lateral positions of the lens, an aperture plate in the gate, projection lamp, &c. The claw member 37 has a fork 37<1> engaged by a pin 37<2> on rod 37<3> reciprocated vertically by a link 42 connected to a pin 43 on a shutter 11 which is itself driven by a pinion 10 meshing with the crown wheel 9. The claw member 37 comprises claws at its upper and lower ends which are respectively used for feeding the film upwards and downwards, the member 37 being rocked about a pivot 38 during its vertical movements under the control of a pin 39 thereon moving within a fork 40 carried by the rod 41 ; movement of the fork by the rod 41 and lever 20 determines the direction of the feed movements. The spools are carried on spindles 6, 7, and are alternatively driven by belts 48, 49 passing round grooves on the crown wheel 9 and round idle pulleys 50, 51, so as to embrace pulleys 46, 47. The upper pulley 46 is connected through gears 44, 45 to the spindle 6, and the pulley 47 is secured to the spindle 7 ; the belts are alternatively tightened to engage these pulleys by jockey pulleys 52, 53 carried on the ends of a rocking lever 54 having an arm 55 connected by a link 56 to a bell crank 57 linked to the lug on the strap 19. The bell crank 57 is also connected by a link 65 to a lever 63 having a spring arm 64 engaging a fork 62<1> secured to a shaft 62 carrying an arm 61 supporting the lens 60. A second arm 68 on the shaft 62 carries a gate aperture-plate, and a lamp house and condenser may be mounted on a bracket detachably secured to the shaft 62; movement of the bell crank thus shifts the lens, the gate aperture, lamp house, &c. from one row of images to the other. The shaft 62 may be axially adjustable, to focus the lens for shortrange projection, by means of a lever 69, and a detachable part of the casing, when placed in position, may engage the lever 69 to adjust the lens focusing to infinity. The lens is provided with an adjustable diaphragm comprising V-shaped notches in two pivoted leaves 66 capable of being pressed apart by means of a cam operated by an external thumb wheel 67 to vary the size of the aperture. The film gate may be secured in its closed position by a slide member 4a having two inclined cam surfaces 4b which press back the rollers 31 when the slide is released to open the gate. A spool box permitting daylight loading with sensitive film comprises end walls 76, Fig. 14, holding a rotatable bobbin 75 and connected by a spiral wall 74 having overlapping ends forming a delivery channel. The film perforations may be interrupted, or one perforation may be elongated, to render the claw movements ineffective at desired points of the film so that prolonged exhibition of titles &c. may be secured. Means comprising additional claws, operable manually through a spring- loaded plunger to restart the film feed, is described. According to the Provisional Specification, the spool spindles may carry indicators visible outside the apparatus to inform the operator as to the direction of feed &c.