Patent GB-540474-A (GB)
Title: Improvements in or relating to cinematograph projection printing apparatus
IPC: G03B27/475
Filed: 1940-08-13
Abstract: 540,474. Printing kinematograph films. BROOKES, N. E. (Technicolor Motion Picture Corporation). Aug. 13, 1940, No. 12951. [Class 98 (i)] A projection printer for kinematograph films is provided with a device disposed in the optical axis which is tipped about two axis perpendicular to one another and to the optical axis, in order to correct for defective registration of the frames on the film being copied, by means each comprising an actuator for tipping the device about one axis and a controller to regulate the degree of tipping. The actuator is movable in opposite directions by spring-pressed pushers engaging shoulders on it, the movement being limited by abutments on the controller, which is provided with means for adjusting it in the same directions, the actuator being prevented from following a re-setting movement of the controller until a detent which holds it is released by means controlled by the film. In the apparatus shown a plane parallel-sided glass plate 1 is placed in the optical axis of a projection film printer between the objective and the film to be printed, and is mounted in the inner ring 2 of a gimbal mounting so that it may be tilted in any direction to adjust the position of the printed frames on the film to correct for lack of registry on the film from which the print is made. The angular positions to be occupied by the inner and outer gimbal rings 2, 4 are predetermined by hand-set controls according to a chart prepared for the film in question, the adjustment coming into operation on release of a holding member or detent 50 by an electromagnet 56 which is energized by the closure of a switch effected by a notch in the edge of the film. Fig. 6 shows only the mechanism for adjusting the tilt of the inner gimbal ring 2. An actuator formed by a rod 17 has a central portion 20 of larger diameter slidably mounted in a reduced central part of the bore of a sleeve 25, forming the controlling member, which is slidable in the bore of a casing 15. Compression springs 23, 24 extend between heads 18, 19 carried by the rod 17 and sleeves 21, 22 which are slidable on it and butt against the ends of the central portion 20. Axial movement of the rod 17 produces tilting of the inner gimbal ring 2 through mechanism comprising a link 36 connecting the head 19 to the lower end of an arm 38 pivoted at 39 and having a pin carrying a roller engaging between flanges 42 on a sleeve 41 which is slidable on the shaft 8 and is connected by a link 44 to an arm 10 depending from one of the trunnions of the ring 2. The device is pre-set by axial adjustment of the sleeve 25 through a rack 27 and pinion 28 on the shaft of a rotary control (not shown) having a spring-actuated locking plunger to maintain it in set position. The movement of the sleeve 25 comprises one or other of the springs 23, 24, but movement of the rod 17 is prevented by the pivoted member 50 which engages and locks a rod 47 secured to the head 19 until released by the energization of the magnet 56. The rod 17 then moves until the springs 23, 24 again counterbalance, thus rocking the gimbal ring 2 to the extent predetermined by the control. Similar means, disposed axially in line with those shown, are provided to rock the shaft 9 of the outer gimbal ring 4, the head corresponding to the head 9 operating directly on the shaft 9 through teeth engaging spiral grooves on the latter.