Patent GB-534440-A (GB)
Title: Improvements in or relating to slide changing devices for projection apparatus
IPC: G03B23/04
Filed: 1940-02-26
Abstract: 534,440. Optical-projection apparatus. KODAK, Ltd. Feb. 26, 1940, No. 3543. Convention date, March 3, 1939. [Class 97 (i)] A slide changing device for optical-projection apparatus comprises slide supply and take-up magazine secured to opposite ends of an apertured plate on which is movably mounted a slide shifting member which, when moved in one direction feeds a slide from the supply magazine into registry with the aperture and simultaneously ejects a slide from the registering position into the take-up magazine, together with shouldered springs which resiliently hold the slide in registry with the aperture and prevent its being moved back on reverse movement of the shifting member. As shown, trough-form magazines 21, 22 are secured to opposite ends of a plate 14 in which is a projection aperture 15. Forwardly-bent flanges 16 at the top and bottom of the plate 14 are secured to rails 17 on a channel-shaped front plate 18, forming grooves 19 in which slides a plate 20 forming the slide-shifting member. The supply and take-up slide magazines 21, 22 are identical, the stack of slides being urged towards the end wall by a follower 35 carried by an inverted-U shaped guide member 34 movable by means of a helical spring 32 in a channel 31 extending beneath the floor of the magazine and projecting forwardly of its front edge. On withdrawing the guide member 34 and tilting it as shown in Figure 9 to engage the shoulder 47 with the front edge of the base of the channel it is held in this position to facilitate the insertion and removal of the slides. A removable inverted-U form clip 37 covering the front end of the channel 31 retains the guide member 34 in position, and when removed allows it to be detached. The slide shifting member 20 is reciprocated by a flexible wire 84 attached to an operating ring 90 and to a post 85 which is secured to the member 20 abd extends through a slot 79 in the plate 18. On the forward stroke a lug 53 on the member 20 engages the edge of the innermost slide 51 in the supply magazine and moves it along the grooves 19 into registry with the aperture 15. A pair of leaf springs 55, Figure 8, bear on the upper and lower margins of the slide and hold it in position, and shoulders 62 on these springs engage the edge of the slide and prevent its moving back on the return movement of the member 20. Simultaneously, the offset leading edge of the member 20, which is bent to form a lug 83, engages the edge 54 of the previously positioned slide and moves it into the take-up magazine 22, the leading edge of the slide engaging an inclined surface 81 formed on a tongue 76 which guides it between the tongue and the slides already in the magazine. On the return stroke of the slide shifting member 20, its leading edge slides over the face of the slide held over the aperture 15 by the springs 55, and at the end of the stroke a spring 69 secured to it and bearing on the rails 17 forces it back against the plate 14 so that its leading edge is in position to engage the edge 54 of the slide on the next forward stroke to move it into the take-up magazine.