Motion Picture Daily (Oct-Dec 1955)

14 Motion Picture Daily Friday, October 7, 1955 FIGURES 3 and 4: The Todd-AO projector. Parts numbered in Figure 3, above, are — I. lamp (not included in Todd-AO equipment); 2. projector head; 3. upper magazine; 4. window; 5. upper fire trap; 6. lens and mount; 7. lens mount bracket; 8. upper motor; 9. inching Itnob; 10. belt housing; II. lower motor; 12. upper base; 13. water line connections; 14. cutout for electrical leads; 15. hold-down screws; 16. leveling screws; 17. lower base; 18. lamp bracket; 19. lamp push button switches; 20. motor push button switches; 21. lower fire trap; 22. motor selector switch; 23. connector hole, optical sound cable; 24. lower magazine. Parts of the mechanisms drawn in Figure 4 are: I. upper fire trap guide roller; 2. fire trap rollers; 3. upper pad roller; 4. feed sprocket; 5. nylon pressure roller; 6. tension indicator; 7. piloting guide roller; 8. adjustable guide roller; 9. lens mount clamping bolt; 10. lower pad roller; II. lower fire trap rollers; 12. fire trap guide roller; 13. hold back sprocket; 14. optical soundhead; 15. sound drum; 16. pressure roller; 17. guide roller; 18. lower film gate pad roller; 19. intermittent film sprocket; 20. aperture plate; 21. pressure bands; 22. upper loop; 23. intermediate sprocket; 24. upper film gate pad roller; 25. film gate; 26. lower loop; 27. lens mount lever; 28. exciter lamp. threaded for optical sound (also see Figure 4). however, according to American Optical technologists, to figure in the optics of Todd-AO projection lenses. 1' ilm pads are accordingly flexible, being long and thin to hug the film continuously as it slides over the curved shoes of the minute, approximately 2800 feet of film are required for 20 minutes of running time. Theatre reels designed for the Todd-AO projector take a total of 3700 feet. PROJECTOR DESIGN The projector of the Todd-AO system is of integrated design developed in collaboration by the American Optical Company and by Philips Industries of Eindhoven, Holland, and New York (North American Philips Company). Fabricated by Philips, it embodies special features of unity and flexibility, including the ability to project standard and CinemaScope film, utilizing either magnetic or optical sound. For shift from one film speed to the other, two motors are installed, one operating the drive at Todd-AO speed, the other operating it at standard speed. A throw-over switch is provided so that only one motor may be energized at any onetime. Both motors are permanently coupled to the mechanism by Gilmer belts and sprocket type pulleys, thus giving a quiet drive. The entire projector, omitting only a light source, has been engineered as a complete unified assembly. The equipment is shown in Figure 3. In Figure 5 the mechanism is pictured from operating side, threaded for optical sound. The various components of the projector mechanism and integrated sound-heads are identified in Figure 4. In Figure 4 the projector is threaded as with 70mm Todd-AO film, through the six-track magnetic pickup. Running through this sound unit, the film is isolated from the rest of the projector by a driven sprocket, one before and one following the unit to prevent unnecessary flutter due to erratic motion of the reel in the upper magazine. It will be noted in illustrations of the projector mechanism that the film proceeds through the gate in a curve. A curved runner plate has been prompted by the greater amount of film exposed to heat of the projection light, and also with reference to the greater weight of Todd-AO film. The curve is of considerably smaller radius above and below the aperture, but slight across the aperture, where its radius is about 25 inches. This bending lends the film added stiffness in a crosswise direction, minimizing undesirable motion across the width of the wide-film aperture. Curvature at the aperture is sufficient,