Stereoscopic viewer

A stereoscopic viewer for a plurality of discrete film images equally spaced peripherally around the edge of a disc-shaped card, said film images being arranged in stereo-pairs of images which provide a stereoscopic effect when said pairs are viewed together through a pair of eyepieces each having a magnifying lens with a focal plane, said card having a plurality of equally spaced radial slots therearound and circularly arranged printed indicia thereon, said viewer comprising:

• a housing including a rear element and a front element, said rear element being completely translucent and having a rear face and a peripheral flange, said rear element having a substantially semicircular bottom portion, and a top portion comprising a first flat top part extending partially across said rear element above a first of said eyepieces, and a substantially rectangular finger grip defining portion extending across the remainder of said rear element above a second of said eyepieces and having a second flat top part with a height greater than the height of said first flat top part, said rear face carrying a detent comprised of a pair of indexing means for registering with a pair of said slots in said card to hold said card selectively stationary with said pair of images aligned in front of said eyepieces;
• said front element including a flat opaque front face having a peripheral flange therearound which mates with said rear face peripheral flange along substantially the entire peripheries of said front and rear face flanges, said front element having a rectangular cutaway portion between said eyepieces through which said printed indicia on said card can be viewed, said front element having a finger grip defining portion opposing said finger grip defining portion of said rear element, said finger grip defining portions of said front and rear elements defining a trigger area therebetween, said front element also forming a cylindrical receptacle;
• an advancing plate for incrementally advancing said card sequentially to view pairs of images on said card, said plate having a hub which projects into said receptacle and rotates relative thereto such that said plate is oscillatable about an axis perpendicular to said faces, between a rest position in which said pair of images are viewed through said eyepieces and an advanced position, said plate having a flat top trigger engaging portion projecting into and across said trigger area between said finger gripping portions of said front and back elements, said advancing plate being cut away adjacent said trigger engaging portion so as to extend below said cutaway portion and the bottom of said first eyepiece such that said plate does not obstruct said first eyepiece and the printed indicia on said card when said plate is in said rest position;
• said plate further comprising a boss adjacent said hub in the direction of said trigger engaging portion, and a window means in register with said second eyepiece when said plate is in said rest position for framing one of said pair of images;
• spring means connected between said plate and said front face for biasing said plate toward said rest position;
• trigger means for moving said plate from said rest to said advanced position, said trigger means including:
• a cylindrical actuator extending through said peripheral flange on said second flat top part of said front element and projecting upwardly from said finger grip member;
• a leg depending from said cylindrical actuator, said leg having a finger means engaging said flat top trigger engaging portion of said plate when said plate is in said rest position for imparting initial rotation to said plate, and lower finger means for pushing said boss to complete said movement of said plate to said advanced position, said lower finger means being out of engagement with said boss when said plate is in said rest position;
• engaging means on said plate for engaging and rotating said card as said plate moves from said rest to said advanced position, said engaging means comprising a yieldable arm on said plate, said arm carrying a pawl for engaging in one of said slots on said card, said pawl having a flat leading face which engages an edge of said slot to advance said card when said plate rotates from said rest to said advanced position, and a curved trailing face which disengages said pawl from said slot when said plate returns to said rest position, said pawl being inclined at an acute angle to said plate in the direction said plate moves to reach said advanced position;
• and
• an opaque mask in front of said focal plane of said lenses between said lenses and said card, said mask having an opening in front of each lens, each opening being a sufficient size and distance from said card to allow viewing of only one framed image through each lens.