Moving Picture Age (Jan-Dec 1920)

February, 1920 MOVING PICTURE AGE 29 iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiio^ Any questions pertaining to projection of films and slides | on the screen will be answered by this department. Address | "Projection," Moving Picture Age, 418 So. Market St., Chicago | If an answer by mail is desired, enclose stamped envelope. | iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiip^ Projection All About the "Rotary" A representative of this department witnessed a demonstration this week of the new Rotary Projector, the world rights to which are owned and controlled by the Educational Films Corporation, 729 Seventh avenue, New York City. The Rotary is of special interest to the school and church because of its several distinctive features, making for compactness, safety and lightness. Also, its mechanism is the result of over two years of experiment, resulting in the "Rotary" as a projector of the "suitcase" type. For several months its sponsors had been working^ on it and ironing out a few unimportant kinks before placing it before the public. They had asserted that it should not be placed on the market until every part of the mechanism had been made as nearly perfect as their mgenuity would make possible. As a result, when the machme was shown and demonstrated to a few interested individuals there was not a hitch in its performance. The "Rotary" threw a picture which for steadiness, clearness, definition and general all-round satisfactory operation has never been bettered by any suitcase type of projector while those present at the demonstration were thoroughly convinced that flicker— the troublesome pest of the usual suitcase machinehad been all but eliminated in the "Rotary." ^^ . So much for the general operation of the machine. Ihe factors just mentioned are exceedingly important to the ultimate user of motion picture machines. He wants a machine that will not produce eye-strain, that presents a screen picture to which he can point with pride and one with a minimum of parts to be cared for and to replace. All of these requirements seem to have been adequately cared for by the designers of the "Rotary." The "Rotary' The "Rotary," showing mechanism. The new machine has many features of construction that are a distinct departure in motion picture equipment, the most noteworthy being the "rotary presser," from which the machine derives its name. This device was worked out to replace the long established Geneva Star and pin-and-cam form of intermittent. The latter mechanism and its derivatives have for many years been employed by both the standard theatrical projectors and the suitcase type, to produce the intermittent motion of the film. But the inventors of the "Rotary" had a new idea. They proposed to employ a scheme whereby the film would be set in motion by a device which exerted its pressure over a considerable length of the film strip instead of through the agency of sprocket teeth and perforations. In their plan the sprocket holes would be used for feeding of film, but not for producing the intermittent motion. In this way there could be no wear on the perforations and the possibilitity of ruptured films would be practically eliminated. After much experimentation they succeeded in accomplishing what they set out to do and in a manner that had proved to be entirely practicable. The remainder of the projector is not dissimilar to others of the same type, with the single exception of the presser. The film comes from the feed reel in the lower compartment, passes through fire valves, over a driving sprocket to which it is held by a pad roller and an idler. After taking a turn up toward the top of the mechanism chamber the film is looped and passes downward through the gate. The gate, which opens by unlatching a simple catch, is equipped with a double pair of tension shoes. The tension exerted by these shoes may be varied by a simple knurled screw on the back side of the gate. At this point in the travel of the film, the machine departs from the standard projector. After passing through the gate the film strip runs under the "rotary presser" up and over an idler, then under the framing device and finally to the take-up reel in the lower compartment. In operation the film is fed continuously to the upper part of the gate. The take-up draws the film tightly along the under-side of the presser. From here on the action is as simple as could be imagined. The presser works continuously. First the toe of the mechanism (where the holes are seen) engages the film by pressing the latter along its edges. Half a cycle later the heel of the presser relieves the toe from its duty and takes up the slack in the celluloid strip. Suppose the machine is about to start and that the presser is in the position for starting. As the motor turns the driving shaft, the toe of the presser bears down upon the film. The latter cannot be drawn back since it is held by the sprocket. There is nothing for the film to do but to be drawn down through the gate by the pull of the presser. At the end of its travel the presser has passed the vertical position and the heel engages with the film and takes up the slack as the toe releases it. _ The rotary presser has been designed in the correct proportion to insure a movement of the film equivalent to four sprocket holes or one frame. Once these dimensions have been established thera is no way by which the extent of the pull-down can be any less or any greater. This does away with chances of unsteady pictures. In framing a picture, the framing device, working similar to an idler, is changed in position and the travel of the film during the next cycle is increased or decreased according to the need. There is little that need be said on the remainder of the projector. Its illumination is adequate for all purposes for which it would be used. A 400 watt incandescent lamp with reflector is the light source. Two piano convex condensers, 3 in. in diameter, and a spirally focused objective made up the optical system. A two-wing flicker shutter is used and, as has been said before, does not cause the annoysome flicker so common with most suitcase machines. Protection from the heat of the light source is assured by a gravity controlled, centrifugally actuated fire-shutter. COLD FIBRE SCREENS MINUSA MAZ-DA-LITE SCREENS A special creation for Churches, Schools, Lodges, etc., made in sizes to suit your requirements. Distributors from Coast to Coast SampUs and information upon re<iiiett MINUSA CINE SCREEN CO. WORLD'S LARGEST PRODUCERS OF r — ] MOVING PICTURE SCREENS. , jP'^agCrfl Bomont and Morfian ' St., Louis. Mo. |El>¥^^i