Twin track cartridge stereoscopic viewer

Claim 1

A multi-track stereoscopic viewer comprising: a hollow magazine having a pair of spaced apart reels disposed therein, a multi-track film having parallel rows of pairs of related stereoscopic images thereon disposed between said reels, said reels including extensions projecting from said magazine whereby said reels can be manually turned to advance the film, said magazine having a viewing aperture whereby a portion of said film is exposed when it is transported between said reels, said hollow magazine having spaced apart guide means disposed therewithin normal to the direction of film transport mounted on both sides of said viewing aperture and a backing member including a flat surface fitted in said viewing aperture with spaced apart elongated framing windows therein which cooperate with the guide means to keep said multi-track film wound on said reels flat against said surface for viewing; a binocular eyepiece including lenses to opTically increase the size of said images slidably mounted on said magazine closing said viewing aperture, said eyepiece having a pair of spaced apart framing windows whereby said eyepiece can be shifted on said magazine to adjacent stereoscopic images on said film whereby related stereoscopic images register with said framing windows of said eyepiece when such images are selected; a stop means cooperating with the magazine to prevent the release of said eyepiece from said magazine and to index it with the several different stereoscopic images of the film when it is shifted to different images, said stop means being removable to permit the eyepiece to be removed, parallel guides on said magazines slidably receiving rail means on the eyepiece, said parallel guides cooperating with the stop means to retain said rail means within said guides, a source of light within the magazine whereby any pair of images can be selected and viewed through said eyepiece, said source of light including a light admitting aperture in the magazine remote from the viewing aperture which is covered by a translucent diffusing screen to provide a subdued source of light within said magazine from light sources outside the viewer, said backing member being disposed between said multi-track film and the slidably mounted eyepiece to protect the film surface, said backing member being apertured to avoid interference with the framing windows and having a felt-like film contacting surface to prevent film scratching.