Patent GB-191415441-A (GB)
Title: Light-regulating Device for Film Printing Machines.
Inventor: ALLISON CHARLES ARTHUR
IPC: G03B27/16
Filed: 1914-06-27
Granted: 1915-04-15
Abstract: 15,441. Allison, C. A., [Motion Picture Apparatus Co.]. June 27. Printing-apparatus. - Relates to apparatus for printing kinematograph film negatives containing several sections and having means, controlled by the negative, for automatically controlling the resistance of the lamp circuit for the various sections of the film. The film controls a switch of a circuit which itself controls the lamp-circuit resistance. The lamp circuit passes through a resistance box containing a number of spaced circular conductors with intermediate resistances and a number of radial conductors extending radially across the circular conductors and spaced therefrom by an insulated card having selective conductive connexions to connect in turn the radial bars with a selected circular conductor. The film 69, Fig. 9, is notched at each change of section, and by means of a trip 71, an electromagnet 73 is energized. The electro-magnet actuates an armature 75, Fig. 5, which forms part of an escapement mechanism 76, 79, which steps a disk 81 and an arm 40 secured thereto. The arm 40 carries an insulated contact 39 one end of which contacts with an insulated ring 38 in the lamp circuit 48, 49, 53, 55, Figs. 2 and 5, and the other end of which contacts with one of a series of contacts 37, each of which is thus automatically engaged in turn, as the arm 40 is stepped, and is in circuit with the selected resistance and the lamp circuit terminal 18<1>. The resistance box and selector comprises a folding box 13, 15. The part 13 is fitted with a series of contact rings 10 embedded in an insulating-material 11, and between each of which is connected a resistance 17. The outer ring is connected at 18<1> with the lamp circuit. The other part 15 contains the electro-magnets and automatic mechanism above described, the electro-magnets being in circuit with the trip 71 through insulated slip-rings 87 secured to the pivot of the casing 13, 15, and spring contacts 92. The part 15 further contains a series of radial bars 33 connected by insulated contacts 27, 25 to the contacts 37. The bars 33 are pivoted at 32 and resiliently mounted by springs 31. The radial bars 33 are adjacent to the rings 10, but between these is inserted a selector chart 62, Fig. 4, which determines which particular ring 10 is to be in circuit with each contact 37 and the corresponding radial bar 33, and thus determines what number of resistance sections 17 are to be in circuit for the corresponding film section. The chart is of insulating-material and is divided into sections corresponding to each film section marked 1 to 25, and an eyelet 63 is fixed in each section at a radial distance corresponding to the ring 10 and resistance to be required. The chart is registered in position by holes 67, 68. An index disk 84, Fig. 7, is marked on its periphery with corresponding numbers 1 to 25, and indicates through the opening 85 the particular film section being printed. Further, to ensure an exact registration of the chart, the lip 105, Fig. 6, of the case 13 is formed with a depending wedge 106 engaging in a corresponding opening 107 in the lip 100 of the part 15, and is held therein by the latch 104. The apparatus may be used for preparing the chart in the following way. A chart, Fig. 8, is divided into sections, and eyelet connexions are fitted at successive distances from the centre corresponding to the rings 10. To find the resistance required for any particular section of film, the contact-arm 40 is stepped by hand until the required resistance is in circuit, and the position of the eyelet and the corresponding ring are indicated by the disk 84. This determines the position required for the eyelet in the film chart 62.