| 摘要 |
1,074,341. Optical projection apparatus. BELL & HOWELL CO. June 11, 1964 [June 11, 1963], No. 24259/64. Heading G2J. In a film-strip or slide projector, loose film-strips or loaded cartridges (74), Fig. 2 (not shown), are received by a magazine comprising a portion (69) which is fixed to the projector housing, and a cover (71) hinged at (72), the film being driven by main sprocket (79) and an auxiliary spring-loaded sprocket (80) which engages the film actually inside the magazine or cartridge, the film passing vertically down between diagonal guides (81, 82) to the film gate passage (137). Plastics spring arms (130) keep the film coiled and engaging sprocket (80). The film gate is defined by two spring- biased glass plates (143) within plates (138, 139) and is swung back to the broken line position to permit the use of framing aperture (28) for slide projection. The film take-up unit (143) is pivoted at (163) to permit this gate movement. Slide transparencies in a carrier are manually fed horizontally in trackway (29) past aperture (28). Vertically downward slide feeding is possible through track (178). The film-strip is manually advanced by rotation of knob 94 against a ball detent, Fig. 1, on the shaft 87 of sprocket (79), sprocket (80) being driven in the opposite direction. Power drive is provided by a reversible electric motor in unit 199, Fig. 1, whose shaft (204), Fig. 5 (not shown), drives worm (208) through dog clutch (207), whereby Geneva movement (209), (213) rotates sprocket shaft (87) incrementally. The projection lens is manually focused by means of knob 45 and a pinion (48), Fig. 3 (not shown), which engages annular teeth (49) in the lens tube (41). Power-driven focusing is provided by shifting worm clutch (207) into engagement with focusing drive worm (232) which rotates focusing gear (240) through intermediate gears and a friction slip clutch. Gear (240) engages the teeth (49). Cooling is by means of centrifugal fan 34, Fig. 1, driven by motor 35, which sucks air over lamp 23 and exhausts it through opening 40. Remote control of the projector is possible, and the film drive may be automatically run by a cam-operated switch (252), Fig. 3 adjacent the Geneva movement. |
