| 摘要 |
399,078. Changing signs. JUSTICE, A. V., 25, Regent Street, Nottingham.- (Neustadt, E. ; 228, Kurf³rstendamm, Berlin.) Feb. 6, 1933, No. 3558. [Class 3 (i).] Optical-projection apparatus.-In apparatus comprising projection screens arranged to form a hollow pyramid and projectors disposed opposite the screens, the hollow pyramid is arranged at the bottom of a frame comprising inclined plates carrying the projectors, and an endless picture strip is carried by tension rollers which bend the strip into a pyramidal shape and cause simultaneous changes of pictures in the projectors ; hollow cylindrical shutters may be provided. As shown, projection screens 3 form a square pyramid, and projectors 1 are carried on a frame 2 by inclined plates 4. The plates 4 have slots 7 serving as guides for a picture strip 8 passing over rollers 17 by which it is tensioned. The strip may comprise a metal band provided with apertures over which interchangeable diapositives are mounted and with perforations engaged by a toothed wheel 10 driven by maltese-cross gearing in a casing 12. Open-ended cylindrical shutters 18 having axes perpendicular to shafts 19 on which they are mounted may be rotated by an endless chain 21 and chain wheels 20, one shaft 19 being driven by maltese-cross gearing in a casing 22. The maltese-cross gearings are respectively driven by a motor 16 through worm gearing 14 and through bevel gearing 24 and worm gearing 23. |
