The invention relates to a double or dual slide projector having two projector assemblies combined in a single appliance. Each projection assembly preferably includes a light source, condenser lens, and slide frame, and the projection assemblies are arranged parallel with each other and movable between two positions for projection and slide change. One possible arrangement for such a double slide projector is shown in my U.S. Pat. No. 3,847,472, issued on Nov. 12, 1974.
The double slide projector in which the invention occurs also uses a common magazine for slides, and a common slide changer for moving slides back and forth between the magazine and the projection assemblies. Slide changing occurs along a slide change plane between the magazine and slide frames of the projection assemblies, when the projection assemblies are in their axially rearward position to locate their slide frames on the slide change plane. The magazine proceeds in a "pilgrim step" motion of advancing two steps and retracting one step so that slides alternately moved into the projection assemblies are returned to the magazine in their original sequence. Such a motion is described in my parent application U.S. Pat. No. 725,140. The magazine is preferably movable along a path adjacent the projection assemblies so that one of the projection assemblies is more remote from the magazine and the other projection assembly is nearer the magazine.
Such a double slide projector requires a simple and reliable slide changer mechanism for alternately moving slides back and forth between the magazine and the remote and nearer projection assemblies. This is solved according to the invention with a slide changer having full-stroke and partial-stroke motions for gripping and moving slides alternately between the different distances required. The invention also aims at simplicity, economy, reliability, and quiet and trouble-free operation in a slide changer producing the required slide movement for a double slide projector.