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1947-48 Theatre Catalog, 6th Edition, Page 342 (328)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 342
Page 342

1947-48 Theatre Catalog, 6th Edition, Page 342

FIGURE 8-511 proiector switching is accomplished in a terminal box located at the top of the mechanism case and these iactlities consist of a motor switch, framing light switch, and changeover button. This location places all changeover operations within the span of a hand. This eliminates the spreadout swttchlng method so commonly used, with its attendant diiticulties in operational procedure.

FIGURE s-The soundheud portion of the projector is built around an internally stabilized flywheel tilter system utilizing a coupling fluid relatively uniform in its t '

I I per ormance over a wrde ran e of variations of temperature. 'l'he rotary stabilizer tunctions in coniunciion with the film loops as Established for its correct operation so effectively as to reduce speed variations to less than 0.25 percent.

The mass weight and the weight ratio between the shell and its internal inertia wheel is such as to allow full stability of filtering to be reached in less than 5 seconds. In explanation of its filter performance, the film is isolated from intermittent sprocket fluctuations by a combined isolation and feed sprocket feeding the film to the sound drum, with its associated scanning components. The holdback sprocket for the takeup reel serves a dual purpose as the sound sprocket.

The film path between this combined sound and takeup sprocket passes around an idler roller in such a manner as to form two film spring elements of great effectiveness in increasing filter effie ciency. The entire bearing assembly for the sound drum and flywheel combines into a readily replaceable unit featuring again rapid equipment serviceability. Figure 9 demonstrates the compactness and field serviceability of the entire assembly.

Sound Track Adiustmen'l'

Film lateral adjustment is obtained by movement of the pressure pad roller holding the film in secure contact with the sound drum laterally and providing a means to secure this adjustment ,permanently by a locking screw. The pad roller additionally is supported on conical bearings which guarantee long life, a low frictional impedance, and low mechanical noise factor.

Edge Guiding

An additional adjustment is supplied in the pad roller bracket assembly for adjusting the tension upholding the film on the sound drum in such a manner that a component of force exists forcing the tilm to guide against the sound track side of the pad roller flange.

This eliminates the necessity of splitting the pad roller and applying direct pressure to the film for guiding.

Sound Optics

The sound optics (Figure 10) is of a type utilizing a cylindrical reduction lens system with the photoelectric cell located inside of the sound drum. This allows full use of all of the illumination transmitted through the film and eliminates the necessity for condensers or mirrors between the film and photocell. Figure 10 shows the location of the components.

A 6-Volt, l-ampere lamp of pro-focus type is utilized for the light source and is held in fixed relationship to the cylindrical reduction lens system. It elimine ates cxciter alignment problems and guarantees rapid, correctly registered replacement of cxciter lamps in case of burnouts.

The cylindrical reduction lens system is adjustable from the front of the proA jcctor mechanism both as to focus and azimuth. As can be seen, all mechanical parts, slit system, photocell and exciter lamps are readily accessible from the front of the projector for replacement or inspection.

The photocell used is of the type CE25 and is protected from electrical disturbances by adequate shielding. The photocell wires are led to the outside of the projector case by a low capacitance neoprene type cable, where it terminates in


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1947-48 Theatre Catalog, 6th Edition, Page 342