Patent GB-510347-A (GB)
Title: Improvements in and relating to projection devices
IPC: G03B21/11
Filed: 1937-10-27
Abstract: 510,347. Optical-projection apparatus. PRATT, V. E., and TAKATS, Z. Oct. 27, 1937, No. 29327. Void. Convention date, Nov. 18, 1936. [Class 97 (i)] Optical - projection apparatus comprises a rotary cylindrical lens or a glass drum supporting a film at the projection position; the film may carry images of the pages of a telephone book, and means may be provided for moving the film, lamp &c. transversely to the direction of feed, so that projection from a single column of any page may be effected, and for feeding the film at either of two speeds forwardly or in reverse. As shown dn Fig. 1, a film 90 passes between spools 77, 78 in a magazine ,59 and over a cylindrical lens 58, to rotate the lens. The film on the lens is illuminated by a lamp 30 adjustable in a lamp house 24, and an image, projected by a lens 157, is reflected by mirrors 163,.166, 170, 175 to a screen 176 in a hood 21 ; the hood 21 may be omitted, the screen being placed within the part 22 of the casing, or both hood and screen may be omitted, a screen being provided in place of the mirror 175. 'The walls of the magazine form a cavity 73, having a slot 178 extending over the width of the film, and also an arcuate recesss 72 clearing the lens 58. A bar extending across the recesss, and movable around it by a grip. 197, may be located as indicated in Fig. 1 while the film is being fed, and may be moved to a position in the projection axis, while the magazine is being loaded into the apparatus, so as to hold -the film out of engagement with the lens 58 during the loading. The magazine is located in the apparatus by pins 6.0 having tapered portions. 65 entering holes 60a and engaging screws 66 adjustable therein, being held in place by a spring-pressed plunger 67 carried by the door 69 of the apparatus. The - spools 77, 78 are carried in the magazine by hollow, internally-splined pivots 79 and by pivots 81 engaging a fixed spring plate 83 ; the film ends are clamped to them by separable hub segments 88 secured by screws 89. The pivots 79 are engaged by splined spindles 107, 110 secured to rotatable sleeves 102 through friction clutches. Alternative forms of gearing are described whereby a driving handle 119, when in the position shown, rotates one or other of the spindles 107, 110, in accordance with its direction of rotation, at a high speed, and, when withdrawn on its spindle to the position shown in broken lines, rotates one or other of these spindles at a low speed. The film may carry a series of images of pages of a telephone book, each page comprising columns spaced laterally across the film, and the lamp 30, projection lens' 157, and mirror 163, may be laterally movable to effect projection of part of the desired column. Rotation of a knob 153, on a spindle carrying a pinion 151 engaging a rack 150 on a yoke 141, moves the yoke laterally. The yoke carries a sleeve 155, containing the lens 157, and the mirror 163, and also carries a rack 148 engaging a pinion 149 on a spindle carrying a pinion 40 engaging a rack 39 on a slidable plate 25 carrying the lamp 30. The lens 157 may be focused by rotation of a knob 162 on a spindle movable with the yoke and carrying a worm 159 engaging a rack on the lens barrel. Each magazine carries a plate 186 formed with projections 187, spaced in accordance with the columns on the film, to snap into a slot in a resilient tongue 188 extending from the yoke, and locate the yoke laterally. Index characters on the plate 186 are visible through a window opening 192 and a slot 191 in the tongue 188. The lamp house 24 is formed with upper and lower louvers for air circulation and with a shield 34 having a light slit. Figs. 22 and 23 show a modification in which the cylindrical lens is replaced by a glass drum 236, and the casing carries a lamp house 216 and contains a condenser system 225, a projection lens 241, mirrors 243, 244, and a screen 214 ; the mirror 244 and screen may be removed and be replaced by a screen 304. The magazine 220 is similar to that previously described except that the light aperture is larger and contains a film having images in which vertical lines run transversely of the film. The mechanism is driven from a handle 297 through a two-speed gearing driving a pulley 291, a belt 290, bevel gears 285, 284, and gearing carried by rocking arms so as alternatively to engage gears on the spool spindles. The lens 241 and mirror 243 are carried by a yoke 240 movable transversely to the film by a linkage operated by rotation of a knob 250 on a sleeve 249 ; a further linkage connected to the sleeve 249 moves a pointer 260 over index characters on a plate 262 on the film magazine visible through a window 263. Focusing of the lens is effected by rotating a knob 265 on a shaft 264, within the sleeve 249, carrying a worm 266 engaging teeth on a lever 269 having a forked end engaging a pin 272 on a sliding bracket 237 carrying the yoke and lens.