Method and apparatus for positive positioning of slides

A method and apparatus for positioning slides in a slide tray for either front or rear projection, so that all slides align top to bottom and side to side in a slide tray. Whether viewing either by front or rear projection, a slide is loaded with the image upside down into a slide tray. Through the use of rectangular guides mounted on opposite sides down the length of a reversible slide tray top, which guides, when viewed in cross-section, are symmetric to the vertical centerline of the slide at the approximate meeting of the slide and the top in the slide tray, whereby if the top is reversed the guides maintain their left and right relationship to said centerline but reverse their up and down relationship, all slides bearing a rectangular cutout in the top edge of each slide frame, which cutout is just able to receive either guide, are properly oriented in the slide tray for front or rear projection only if the top seats.

BACKGROUND 
1. Field of Invention 
This invention relates to slide trays for slide projectors. 
2. Description of Prior Art 
A slide projector is used to project either to a front or to a translucent 
reverse screen. Generally, slide projectors utilize a slide tray with a 
locking top. A slide may be positioned into a slot in the slide tray in 
one of eight positions, each of four sides up and to the front and rear. 
Only one position is correct. Heretofore, aids for the orientation of 
slides included color coding and labelling. Nevertheless, each of these 
aids required the projectionist to review each slide for orientation as it 
was loaded into the slide tray. Even then, the projectionist was free to 
make an error in orientation of the slides. 
SUMMARY OF INVENTION, OBJECTS AND ADVANTAGES 
Several objects and advantages of the present invention are: 
(a) to provide for visual alignment of the slides by a projectionist 
viewing the alignment of a cutout in the slide frame; 
(b) to provide confirmation of a projectionist's visual alignment of slides 
by means of a tray cover which will not seat if all the slides are not in 
proper alignment; 
(c) to provide for carryover from machine processed film orientation in a 
slide frame bearing a cutout to positive orientation of slides in the 
slide tray by a projectionist; and 
(d) to provide a design adaptable to inexpensive modification of existing 
slide tray covers and slides to benefit from the invention. 
Still further objects and advantages will become apparent from a 
consideration of the ensuing description and drawings.

REFERENCE NUMERALS IN DRAWINGS 
1. Slide tray cover 
2. Slide tray cover wall 
3f and 3r. Slide alignment protrusions, front and rear projection 
respectively 
4. Slide, including film and slide frame 
5. Slide cutout for receipt of slide alignment protrusions 3f and 3r 
6. Slide tray cover seating lips for a rectangular slide tray 
7f and 7r. Cover reversing protrusions for rectangular cover, front and 
rear projection respectively 
8. Slide tray side wall cutouts for receipt of slide tray cover alignment 
protrusions 7f or 7r for a rectangular slide tray 
DESCRIPTION--FIGS. 1 AND 2 
FIG. 1 shows a cross-section perspective of common elements of the 
apparatus forming a slide tray cover at the point of loading a slide into 
a projector. FIGS. 1F and 1R show FIG. 1 in cross-section, reversed around 
the designated X-axis. The cover is designated by general reference 
numeral 1. Cover 1 of the slide tray is formed by a wall 2 of variable 
thickness and surface area, and slide alignment protrusions 3f and 3r 
which are located on opposite sides of wall 2. Wall 2 is of dimension to 
act as a cover for a slide tray. In cross-section, slide alignment 
protrusions 3f and 3r form equal rectangles, typically of width 1.27 cm 
and height 0.5556 cm., which rectangles when cover 1 is seated on the 
slide tray, are symmetric to the vertical centerline of the large surfaces 
of a slide loaded into the slide tray. In length, slide alignment 
protrusions 3f and 3r form continuous guides of uniform dimension down 
cover 1, e.g.; for a annular cover, the alignment protrusions form 
uniform, rectangular rings; for a rectangular cover, the protrusions form 
rectangles. The surfaces of cover 1 bear appropriate legends for front or 
rear projection. 
FIGS. 2F and 2R show a front and rear view respectively of a slide, said 
slide designated by general reference numeral 4. Numerals 5f and 5r 
represent the front and rear views of a single cutout, slide cutout 5, in 
the top edge of slide 4 ("top" in relation to the top of the slide when 
loaded in the tray with the film image loaded upside down), said slide 
cutout 5 being of the same shape but slightly larger dimension than slide 
alignment protrusions 3f and 3r. In operation, the "up" edge of slide 4, 
bearing cutout 5 as depicted in FIGS. 2F and 2R, is approximately flush 
with the bottom of cover 1. 
OPERATION--FIGS. 1 AND 2 
A typical embodiment of a slide's alignment for front projection at its 
point of loading into the projector is illustrated by FIG. 1F and FIG. 2F. 
In use, the legend on cover 1 for either front or rear projection is read 
by a projectionist to determine the proper "up side" of cover 1 for front 
projection. Then the projectionist visually aligns protrusion 3f with 
slide cutout 5 in the 5f position for all slides in the slide tray. Cover 
is then seated to the slide tray to ensure positive alignment of all 
slides. If cover 1 will not seat, one or more of the slides are not 
properly aligned for front projection. Corrective action is removal of 
cover 1 and visual inspection and alignment of cutout 5 for all slides 
until cover 1 will seat. 
A typical embodiment of a slide's alignment for rear projection at its 
point of loading into the projector is illustrated by FIG. 1R and FIG. 2R. 
In use, the legend on cover 1 for either front or rear projection is read 
by a projectionist to determine the proper "up side" of cover 1 for rear 
projection. Then the projectionist visually aligns protrusion 3r with 
slide cutout 5 in the 5r position for all slides in the slide tray. Cover 
1 is then seated to the slide tray to ensure positive alignment of all 
slides. If cover 1 will not seat, one or more of the slides are not 
properly aligned for rear projection. Corrective action is removal of 
cover 1 and visual inspection and alignment of cutout 5 for all slides 
until cover 1 will seat. 
DESCRIPTION--FIGS. 3, 4, AND 5 
FIG. 3A shows a partial front-view, cross-section of an annular slide cover 
seated on an annular slide tray, the annular slide tray cover embodying 
the elements described in FIG. 1. FIG. 3B shows a 1/4 top view of an 
annular slide tray cover, including the solid concentric, rectangular 
rings formed by slide alignment protrusions 3f and 3r and the concentric 
inner and outer sides of wall 2. 
FIG. 4 shows a front-view, cross-sectional perspective of a rectangular 
slide tray cover that embodies the elements described in FIG. 1. 
Additional elements shown are optional slide tray cover seating lips 6 and 
rectangular protrusions 7f and 7r, typically 0.5556 cm. in depth. and 
meeting corresponding cutouts, slide tray side wall cutouts 8, where cover 
1 and a slide tray side walls seat. Slide tray cover seating lips 6 seat 
snugly over the slide tray side walls to a typical depth of 0.5556 cm. 
FIG. 5 shows a cross-section perspective of a rectangular slide tray with a 
visible slide 4 positioned for front projection, the slide tray in 
position to receive the slide tray cover, FIG. 4, by the insertion of 
protrusions 7f into slide tray side wall cutouts 8. 
OPERATION--FIGS. 3, 4 AND 5 
The operation of the elements of FIGS. 1 and 2 are the same for those 
elements embodied in FIGS. 3, 4, and 5. In the case of an annular slide 
tray arrangement, the concentric relationship depicted in FIG. 3 between 
protrusions 3f and 3r ensures that the protrusions will remain to the left 
and right respectively of the centerline as depicted in FIG. 1. In the 
case of a rectangular slide tray depicted in FIG. 5, cover 1 bears 
alignment protrusions 7f and 7r that will not mate in slide tray side wall 
cutouts 8 permitting a meeting between the slide tray cover and slide tray 
unless cover 1 is reversed so that protrusions 3f and 3r remain 
respectively left and right of each other in relation to the centerline in 
FIG. 1. Slide tray cover seating lips 6 for rectangular covers ensure a 
snug fit between the slide tray cover and the slide tray. 
SUMMARY, RAMIFICATIONS, AND SCOPE 
Thus the reader will see that the meeting of the alignment protrusions and 
slide cutout provides a positive means for ensuring the alignment of 
slides in a slide tray. This is particularly useful to align slides for 
front and rear projection. Furthermore, the invention has additional 
advantages in that: 
it provides for visual alignment of the slides in the slide tray by a 
projectionist viewing the alignment of cutouts of slides; 
it provides confirmation of a projectionist's visual alignment of slides by 
means of a tray cover which will not seat if all the slides are not in 
proper alignment; 
it provides for carryover from machine processed film orientation in a 
slide frame bearing a cutout to positive orientation of slides in the 
slide tray by a projectionist; and 
it provides a design adaptable to inexpensive modification of existing 
slide tray covers and slides to benefit from the invention. 
Although the description above contains may specificities, these should not 
be construed as limiting the scope of the invention but as merely 
providing illustrations of some of the presently preferred embodiments of 
this invention. For example, protrusion and cutout can have other matching 
shapes permitting insertion of the protrusion into the cutout including 
squares, half-circles, etc.; the protrusions could be movable rather than 
fixed via a slide, hinge, recess, etc.; the protrusion dimension down the 
long axis of the cover could be continuous or noncontinuous guide; cutouts 
could be of double dimension given in the embodiment with a sliding cover 
over one-half such dimension, or a sliding cutout of single dimension, 
etc.; the protrusions could be on a side wall or a bottom to a container; 
the protrusion wall could be curved, straight, etc.; the slides can be of 
any dimension and curvature; the slides can be replaced by cards, fiche, 
computer cards, blocks and other solids (including curving, corrugated, 
etc.) which can be stacked or aligned; in the standard slide tray where 
each slide is mounted in an individual slot in the tray, the top and 
bottom protrusions could be affixed not only for positive front and rear 
alignment but for specific ordering of slide in the slide tray, e.g. the 
top and bottom protrusions forming an X shape when viewed from above a 
rectangular cover would insert into cutouts in slides forming a diagonal 
corresponding to one diagonal of the X shape for front projection and the 
other diagonal for rear projection when the slides were arranged in proper 
viewing order and loaded into the rectangular slide tray; and the design 
supports a side loading slide projector with a removable top by removal of 
the cover bearing the protrusions after positive alignment of the slides 
but before projection of the slides. 
Thus the scope of the invention should be determined by the appended claims 
and their legal equivalents, rather than by the examples given.