Patent GB-343892-A (GB)
Title: Improvements in and relating to film printing machine
IPC: G03B27/475
Filed: 1929-11-20
Abstract: 343,892. Film-copying apparatus. CROAD, A. K., 70, Chancery Lane, London. -(Photocolor Corporation; 1650, Broadway, New York, U.S.A.) Nov. 20, 1929, No. 35494. [Classes 97 (i) and 98 (i).] A film copying machine has two rotatable heads fitted with supply and take-up spools, copying and exposure gates and intermittent film feed mechanisms. The rotation of the heads and the film movements are both derived from one main shaft. The film-gates are connected by a light trapped lens tube and the heads are adjustable for focusing, alignment and size registration. By alternative gearing between the heads and the main shaft synchronous and alternative relative movements of the negative and positive films are possible for different requirements, e.g. ordinary step printing ; selective step printing ; printing alternate pictures of a negative film on opposite sides of a doubly coated positive stock ; and printing to obtain a positive film with two series of pictures, ACCEE.... and BBDDFF .... respectively on opposite sides of a doubly coated stock from a negative with a series A B C D E F .... The driving connections for some requirements may not involve rotation of the heads. The film gates in the rotatable heads are provided with laterally resilient guides, and a reciprocating pressure plate with four registering pins at the corners thereof . Intermittent brake mechanism is provided for stopping the rotation of the heads, and synchronously acting locking devices for registering the heads in exact operative position. An indicator is also provided for indicating deviations from the correct position. For varying the printing light, more especially for negatives with recurring colour pictures, a filter may be intermittently interposed by electric contacts and solenoid mechanism, or a variable rheostat may be used. The mounting and adjustment of the heads.-The heads 5, 6, Figs. 1 and 5, for the negative and positive films respectively are rotatably mounted in yokes 101, 102 which are slidably adjusted in guideways 101a by screw rods 107, 108 and pivoted arms 105, 106, and can be clamped by bolts 101b, Fig. 2. The heads can be centred in their yokes by adjusting screws 113. Projecting andfocusing arrangements.-Light-tight connection from the lamp house 7, Figs. 1 and 10, through the two gates, is provided by surrounding each head adjacent the gate by a two-part hinged shield 73. The hinged part 75 on the negative head 5 has a bellows connection 77 with the pressure plate at the gate. An outer shield 81, Figs. 5 and 10, carrying the condenser case 80, the shutter and movable light-filter is mounted on a swinging arm 82. Over the fixed part 74 is a similar shield 85 with a tubular passage 79 to the gate. The positive head has a similar swinging shield 88 and tubular fitting, the rear shield being omitted leaving a focusing aperture through the corresponding bellows fitting. The lens mounting 91 is supported on an independent frame 121 and makes telescopic connection with the shields 85, 88. The film arrangements in the heads.-The negative film is wound from a supply drum 53, Fig. 1, to the take up drum 52, which is driven by a belt-driven friction pulley 55, Fig. 3. The belt driving wheel 57 is in gear with an annular gear wheel 58 freely mounted on the head 5, and can be locked to the stationary yoke 101 by the latch 59. Thus locked the wheel 57 and take-up spool are driven on rotation of the head. Alternatively if the head is not rotated the wheel 58 can be driven by using a direct belt drive from a pulley 61, Figs. 2 and 5, on the vertical shaft 71 which also drives the shutter in the casing 80. The positive film is fed in the opposite direction from the spool 95, Fig. 1, to the take-up spool 96 which has similar alternative driving arrangements. The feed sprockets 50, 51 Fig. 3, to and from the gate are driven from a vertical shaft (145<1> shown on Fig. 16), and the intermittent feed through the gate is by a doublecam-operated claw feed mechanism driven from the vertical shaft 145. The film gate and registering arrangements.- Resilient lateral guides 23, 24, Fig. 3, connected by parallel links are provided, one of which may however be fixed. A resilient reciprocated pressure plate 34, Figs. 3 and 19, on the film gate carries four registering pins 35 engaging corresponding recesses 36 round the film aperture. The recesses may be just slightly larger than the pins. The plate 34 is intermittently pressed on to the film by a lever 37 which is pivoted to the gate 25 and reciprocated by a cam 40 on the film feed shaft 27<1> by a two-part slide 41, 42 with a hook connection. To be able to open and close the gate with the registering pins in operative position independently of the normal stopping position of the cam shaft 271, this cam shaft 27<1>, Fig. 21, is driven by a projection 46, Fig. 20, on the driving pinion wheel 45, whereby an independent rotation can be given to the shaft 271. The driving mechanism.-The rotation of the heads and intermittent movement of the films are both derived from the main shaft 10, Figs. 1 and 2, on which are two main pin or star cam wheels 125, 161, Figs. 11 and 12. There are four star wheels 126, 135, 160, 169 which can be fixed or loose on their respective shafts, and the driving wheels 125, 161 can be fitted with alternative numbers of pins or substituted blocks, according to the alternative requirements of the machine. The star 126 is on shaft 127 which is in gear with bevel wheels 129, 136 on the rotating heads. The star 135 is on a shaft 136 which drives a vertical shaft 138 having a pinion 142, Fig. 3, in gear with a loose wheel 143 on the head. This wheel 143 is also in gear with a wheel 146<1> (and another similar wheel not shown) on vertical shafts in the head which operate the film gearing. The film movement is accordingly dependent on the relative movements of the head and the loose wheel 143. The star 135 can be moved into inoperative position (shown in full lines on Fig. 1) and locked by a collar 150 engaging the frame of the machine, whereby the shaft 138, and wheels 146<1>, 143 are locked. Also the feed movement of the film by the shaft 138 can be varied by a double crown pinion 137<1> and alternative pinions 139, 140. The driving means for the positive film.-This is controlled by the cam wheel 161 and star wheels 160, 169. The star shaft 162 has a double reversible pinion drive 163, 164, 173 to the vertical shaft 175 in gear with a loose pinion on the positive head (corresponding to the pinion 143 above described). The star 169 controls the movable clutch 165 of the reversing gearing, which may be fixed in either position or intermittently operated by the star according to the required feed movements of the negative film. Braking and locking mechanism for the heads.- Brakes 200, 201, Fig. 5, are applied by lever mechanism 204, 208 on the shaft 240, Fig. 2, operated by pins on the main star cam wheel 125. The brakes are released by a counterweight 204a and come off just before locking mechanism registering the heads in position operates. This mechanism comprises tapered bolts 212, Fig. 5, engaging holes in a plate 214 on the head. These plates can be preset by precision screws. The bolts are operated by lever mechanism 215, 217, Fig. 2, pins on the driving cam wheel 125, synchronously with the head rotations. Positionindicating mechanism is provided operated by a pivoted lever 115, Fig. 5, one end of which engages notches in the head.