A slide magazine insertable in a side opening in a slide projector and comprising a plastic body with a continuous rail having two elongated sidewalls and two arcuate endwalls, and a cross-plate giving the body an H-shaped transverse cross-section. A grooved drive shaft is rotatably mounted within one arcuate endwall, and a plurality of plastic slide holders are slidably mounted on the rail, each having a dovetail-like notch in its inner side receiving the rail, two detent fingers extending toward each other on the inner side of the rail, and a slotted slide-holding frame on the outer side. The magazine body is divided into relatively movable end sections that are urged together by a spring for pressing the stack of holders toward the shaft, and the track is shaped to tilt the holders toward the shaft for positive pick-up of the detent fingers by the grooves in the shaft, to feed the holders around the rail, the grooves and the fingers having mating V-shaped cross-sections. Slideways span the gaps in the rail between the end sections to support the holders across the gaps, through the fingers, independently of the rail.

The projector includes two projection optics systems and two slide gates which move slides acquired from a slide receptacle into and out of a viewing position in all of the projection optics systems. The slide gates are movable between a first position, which is common to both slide gates and in which slides are moved between the slide receptacle and the side gate means, and the second position in one of the projection optics systems. The slides move by gravity from the slide receptacle into the slide gates and by means of a slide lifter from the slide gates back into the slide receptacle. A combination of a scalloped gear matching the depending lugs on the slide receptacle and a stepping motor to control the movement of the gear provides efficient and economical control over the movement of the slide receptacle. The slide gates, the slide lifter, and the slide receptacle gearing are independent of each other in operation, so that they may be activated in any sequence.

A slide projector system includes a projector and a removable slide cartridge which encloses an endless belt for transporting slides along a generally horizontal pathway. The removable cartridge, when loaded into the projector, advances slides to a viewing gate for projection onto a screen or the like, wherein the viewing gate is associated with an access port in the cartridge to permit direct loading and removal of the slides thereby facilitating the instantaneous projection and viewing of the slides as they are loaded. In one preferred form, the slides are carried along an oblong pathway for presentation at a single viewing gate whereat a drive spindle and a slide catcher wheel cooperate to individually hold the slides. In another preferred form, an expandable endless belt carries the slides along a generally Y-shaped pathway for presentation at either of two separate viewing gates. This expandable belt comprises alternating connected links of slide holders and track-guided expandable webs which are driven through the cartridge by two independently actuated drive spindles.