Motion Picture News (Jan-Feb 1920)

t anuar y j 4 , i g 20 nil ^[9 ^ixestiorts' I Artswered^ demonstration of New "Rotary'' Projector Gives Convincing Proof of Correct Design Latest Addition to Portable Machines Reveals Novel Departures from Usual Mechanisms 'HE r ""'^ Jeen •> made its debut in last week's several months its sponsors had ■ ■ ' • -tj a i^jfi unimore the public. o: be placed on e\'er> part ot the mechanism nearly perfect as their ingenuit>As a result, when the ma' ~ >:rated to a tew innot a hitch in its threw a picture ness, definition and gen operation has never by any sait-case t>-pe of projector, " at the demonstration were that flicker — the trouble. Jsual suit-case machine — had n all but eliminated in the "Rotarj." So much eration of the ma The Dned are exceeding mportant :o ^luniuu user of motion picmachines. He wants a machine that will not "a: presents a screen picture : with pride and one with a be cared for and to replace, ents seem to have been adeoy the designers of the " Ro Fimld make possible, tune w?.; ;re$tec erf — •h: ra ^ hi : Miroug 1 J So ■hioe. ' •mi new he Dim. machine has many featnres of con".: 2rc a distinct departure in motion the most noteworthy being the from which the machine derives ievice was worked out to replace ed Geneva Star and pin-and-cam ent. The latter mechanism and e for many years been employed ird theatrical projectors and the produce the intermittent motion But the inventors of the Rotar>" had a new ea. The;, proposed to employ a scheme wherewould be set in motion by a de\-ice d its pressure over a considerable -; _:e film strip instead of through the igoKy of sprocket teeth and perforations. In heir plan the sprocket holes would be used for ceding of film but not for producing the intertent motion. In this way there could be no r on the perforations and the possibility of vjred films would be practically eliminated, r much experimentation they succeeded in ac \ Ro:-. }-atine t-e ihat they set out to do and in a man: roved to be entirely practicable. The the only portable machine incorpo rotary presser." on shows, the remainder of the . issimilar to others of the same ype, with the single exception of the presser. Ihe film comes from the feed reel in the lower rooqartment. passes through fire y-alves, over a ariroig sprocket to which it is held by a pad roDer and an idler. After taking a turn up toward he top of the mechanism chamber the film is coped and passes downward through the gate. The gate, which opens by unlatching a simple ratch, 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 fide of the gate. At this point in the travel of the fihn. the ma chine departs from the standard projector, .■\tter passing through the gate the film strip runs under the " rotarj presser " up and over an idler, then under the framing device and finally to the takeup 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 imder-side of the presser. From here on. the action is as simple as could be imagined. The presser works coniir.uousiy. 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 shown in Fig. 1. .\s 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 there 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, .-^s a SPRO I D L CKET FOCUSINC E»» mff ■ ARM PER CEO OCKCT HA MO CRANK Fig. 1 — Mechanism c£ new " Rotary " Portable Projector. Complete marhine shown on next page