Patent GB-196243-A (GB)
Title: Machine for printing positive films
IPC: G03B27/16
Filed: 1922-11-24
Abstract: 196,243. Debrie, A. L. V. C. April 13, 1922, [Convention date]. Printing-apparatus with continuous movement of negative and printed surface.-In apparatus for printing kinematograph films of the kind described, for example, in Specification 179,538, having means for automatically varying the intensity of the printing light for different sections of the film by a stencil strip driven intermittently from the negative film, (1) electric contacts controlling the intensity of the printing-light are operated by two series of levers co-operating, through selectively-arranged perforations in the stencil strip, with two series of depressions in a drum over which the stencil strip passes, and (2) a device is provided which ensures proper insertion of the stencil strip into the apparatus. In the form shown, the drum 2 which drives the stencil 1, and is driven by a maltese-cross arrangement as in the machine described in Specification 179,538, has four sets of nine notches, each set comprising two rows 4, 5, the sets being 90‹ apart, and each notch being adapted to receive a projection 8 or 10 on one of a set of nine levers 7, 12 which are pressed against the drum 2 by spring-urged levers 13, 18. Contacts 17, 22 on the levers are included in parallel arms in the lighting circuit shown in Fig. 2, so as to cut in various sections of a rheostat comprising two parts 23, 24, the first of which is in large steps wired to the contacts 17, and the second in small steps wired to the contacts 22. The stencil travels between the levers and the drum and is perforated so that at each quarter-turn of the drum a selected projection 8 and a selected projection 10 drop into the corresponding notches, and close a contact 17 and a contact 22. Contacts 17<1> and 22<2> are shown closed in Fig. 2, thus completing the circuit of the printing lamp 25 through all the part 23 of the rheostat and two steps. of the part 24. The arrangement shown gives twenty different intensities of illumination. The stencil 1 has a notch 29 in one edge, and is inserted so that this notch coincides with a recess 30 formed on the drum between the two rows 4, 5 of one set of notches. Into the recess 30 fits a roller 31 on a spring-urged lever 32 controlling contacts 34, 35 in the circuit of a solenoid 37, Fig. 3, whose core 38 acts as a stop for a cam 40 on the spring-controlled shaft of a lever 42 which serves to actuate the main driving clutch of the machine. When the roller lies in the recess, the solenoid is energized and the core 38 withdrawn from the cam 40, the driving gear being therefore unclutched. The apparatus is started by turning the handle 42 by hand into the position shown in Fig. 3, and holding it there until the drum 2 has been displaced, as described in Specification 179,538, to effect a change in the printing-light. This displacement causes the notch 29 to move away from the roller 31 whereupon the edge of the stencil displaces the roller away from the drum, opening the contacts 34, 35 and de-energizing the solenoid 37, so that the core 38 drops into engagement with the cam 40 and holds. the clutch in engaged position for the subsequent operation of the apparatus.