Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Descrl ~ on
M~LTIPLE PROJECTION OPTICS SLIDE PROJECTION
APPARATUS USING A CIRCULAR SLIDE TRAY,~
HAYING FIXED-POSITIO~ SLIDE GATES
Technical Field
This invention relates generally to thP slide
projector art~ and more specifically concerns a multiple
projection optics slide projection system which includes a
circular slide tray and two fixed-position slide gates in
which slides are projected.
Ba~round Art
In the consumer slide projector market, the most
successful design in recent years incorporates a circular
slide receptacle or tray, for storage of the 91 ides to be
projected~ In operation, the slide tray, which is mounted on
top of the slide projector, is rotated abou~ a fixed verti-
cal axis so that the compartment containing the slide to be
projected is in regi5try with the slide gate therebeneath.
The slide moves through a slot in the bottom of the slide
tray by gravity into the slide gate and is then projected.
Following projection, the slide is moved by a mechanical
lifter from the slide gate back into its compartment in the
slide tray. The same process occurs for each slide to be
projected.
Exemplary of this design currently on the market
is a Kodak slide projector and its mating slide tray, sold,
respectively, under the trademark Carousel. An example of
a similar projector in the patent literature i~ U~ S. Patent
~5~
No. 3,276,314 to Robinson. Such mechanically operated and
controlled slide projectors have been extremely successful
in the consumer slide projector marketO
However, such conventional slide projectors have
only one projection optics system, including a single pro-
jection lens. Thus, the previously projected slide must be
moved from the slide gate back into its original compartment
in the slide tray before the next slide can be moved into
the gate and projected. Thi~ results in a delay between the
projection of successive slides7
Lap-disYolve projector arrangements have been
developed to eliminate this delay and provide a smooth tran-
sition between successive slidesO In one solution, which is
currently used extensively, several single optics slide
projectors are operated together, controlled by an interface
device. It is not uncommon for three or even more projectors
to be used together for a sophisticated slide presentation.
Another solution i~ a single projector having
multiple projection optics systems. However, significant
difficulties have been encountered with 5uch an arrangement,
particularly with respect to the slide movement between the
slide tray and the two optics systems. Initial attempts
included two magazine-type slide trays, one for each optic~
sy-~tem. Such an arrangement basically is two p~ojectors
contained in a single housing. The next development used a
sin~le magazine or drum slide tray in which slides were
moved out of the slides of the slide tray. The slide tray
wa~ moved forwards and backwards in a particular sequence in
order to maintain proper storage of the slides. Such a StLU-
ctur~ is shown in U. S. Patent No. 3,462,215 to Floden.~lthough the optic~ systems for both of the above solutions
are relatively simple, neither solution was usable with a
circular slide trayO
Initial development of a multiple-optics slide
projector which was capable of using a circular slide tray
is ~hown in U. S. Patent No. 3,501,233 to Winkler et al.
~ ~s~
However, the Winkler structure is quite complicated, in-
clude~ a slide tray support structure in which the ~ray is
alternately rocked about points on opposing sides of the
tray, and more importantly, reyuires a careful initial pos-
itioning of the slides into two separate group~ in the tray.
The next advance in the art is exemplified by U.
S. Patent No. 3,6fl9,140 tO Harvey, which teaches a circular
slide tray and two projection optics systems, in which
81 ides can be loaded in the tray in a normal sequence How-
ever, the tray in operation is shifted laterally to acsessthe two slide gates, as well as rotated. Such a structure is
complex mechanically and expensive to implement. The next
development in the art is exemplified by Patent No.
4,165,161 to Kramer, which solved ~he problem of Harvey by
uslng swinging slide gates, which moved in operation between
a common load position and separate project positions. The
Kramer structure, how0ver, is also fairly complex and fairly
~ophisticated to both operate and maintain~
Thus, the lap-dissolve ~lide projectors known to
the art at the t~me of applicant's invention were quite
complex mechanically, particularly with respect to the tray
drive system and/ox the projection optics sy~em, an~ in
~ome cases required special loading of the slides in the
slide tray.
Disclosure of the Invention
Accordingly, the present invention is a slide
projection apparatus which is adapted to carry a circular
slide tray which has a lower pan portion with at least one
slot therein through which slides can move and an upper
receptacle portion comprising a ~eries of compartmant~ in
which slides are arranged in a predetermined sequence, thP
receptacle portlon being rotatable relative to said pan
portion about a single vertical axis. The projection appara-
tu~ includes first and second projec~ion optic~ systemsdefining first and second image projection paths, each pro-
~ :il ~5~3~f~
jection optics system including a fixed-position slide gate
located beneath the circular slide tray, wherein slides move
into and from said slide gat~s ~elative to the circular
slide tray, the image projection systems being arranged
5 relative to each other and to the slide tray such that each
compartment in the slide tray can be brought into regis~ry
with each slide gate and such that slides poRitioDed in the
slide tray in the predetermined sequence can be displayed
without reversal, in said predetermined sequence. The ~lide
10 projection apparatus includes means for rotating the circu-
lar slide tray about the fixed vertical axis to access each
. compartment of the circular slide tray relative to each
51 ide tray.
15 Brief Description of the Drawings
Figure 1 is a plan view of one embodiment of the
slide projection ~pparatus of the present invention~ showing
two independent projection optic~ sy~tems, with fixed posi-
tion slide gates, the slide tray for the apparatus being
20 shown superimposed relative to the projection optic~ sys-
tems.
~ igure 2 is a single projection lens embodimen~ of
the slide projection apparatus shown in Figure 1.
Figure 3 is a variation of the embodiment of Fig-
25 ure 2, with only one light source.
Figure 4a is a plan view showing a portion of one
embodi~ent of the tray drive structure of the present inv2n-
tion which can be used with any oE the embodiments of Fig-
ures 1-3.
Figure ~b is an elevation view of the structure of
Figure 4a.
Figure 5a is a bottom plan view showing a portion
of another embodiment of the tray drive ~tructure of the
present invention which can be used with any of the embodi-
35 ments of Figures 1-3.
s
Figure 5b i~ an elevational view of the embodiment
of Figure 5a,
Figure 6 i5 an elevational view showing a str~c
ture for driving the receptacle portion of the ~lide tray
which can be used with the embodiments of Figures 4 and 5.
Best Mode For Carryin~ Out The Invention
Figure 1 shows one embodiment of the apparatus of
the pre~ent invention, in which each of two projection op-
tic8 systems includes a separate projection lens. The slidetray is shown superimposed in dashed outline to ~how the
relationship between the two projection optic~ systems and
th~ tray.
Projection optics system~ 12 and 14 are contained
in a conventional projector hou~ing 10. A single circular
slide tray 16 is used to store the ~lide~ for the apparatus.
~he slides may be conventionally loaded in the slide tray in
the sequence in which they are to be displayed. In opera-
tion, slide~ move from slide tray 16 by gravity~ lo~ered by
a conventional lifter apparatus (not shown), into one or
the other oE the projeetion optic~ eystem~, and are moved
rom the projection optics system~ back into the slide tray
16 by means o~ the lifter. The particular mechanism or
a~tually moving a slide between the slide tray and the image
projection s~tems form no part of the present invention,
and hence is not shown herein in detailO Referen~e i~ made
to the patents mentioned above, particularly the '161 pat-
ent, for example~ of approximate ~lide moving structure.
Projection optics ~yst*m 12 define~ a straight
projection path along the left ~ide of the projector. It
include~ a conventional light source 18~ a heat filter 20, a
conden~er len~ 22, a fixed po~ition ~lide gate 24 into and
from which slides are moved relative to the tray 16~ and a
projection lens 26~ An additional light filter element ~not
shown) can be positioned in projection op~ic~ ~ystem 12 to
equalize the light on the ~creen between the two optic~
systems, if necessary. The indlvidual elements par se of
the projection optics ~ystem 12 and their relative spacing
are known in th~ art. Slide gate 24 in the pr~ent invention
is positioned within the projector apparatus such that the
compartments of the 51 ide tray 16 may be sequentially moved
into registry therewith by rotation of the tray alone~ i~e.
without lateral movement or rocking of the tray~
Projection optiGs sy~tem 14 defines an angled
projection path~ The ini~ial portion of the projec~ion path
Of optics system 14 is at an angle to the projection path
of projection optics system 12. ~he remaining portion of the
projection path of optic~ sy~tem 14 is parallel to the pro-
jection path of optics system 14, so ~hat the lon~itudinal
axe~ of the respectiv~ projection lenses thereo~ are paral-
lS lel. P~ojection optics system 14 includes a light source 30,a heat filter 30, a condenser lens 34, a fixed po~ition
slide gate 36, a reflecting mirror 38 and a projection lens
40. Again, the ~lem*nts per S8 of projectlon optic~ sy~tem
14~ including mirror 28~ and the relative spacing thereof,
29 ar~ known-
Projection optics sy~tem 14 is arrangPd 8C thatthe slide tray compartments can be moved sequentially into
registry with the slide gate 36, and slide gate 24, by rota-
tion of the tray alone, without any lateral movement there-
Of D Further~ projection optic~ sy~tem 14 is arranged rela-
tive to projection optics system 12 ~uch that the re~pective
pro~ection lenses 26 and 40 are ~ub~tantially adjacent each
o~her~ with projection lens 40 being positioned slightly
forwardly of projection lens 26. The arrangement of Figure
1, as with the arrangement of Figures 2 and 3, permits
slides to be load~d in a conventional sequence in the ~lide
tray and di~played in that sequence, without any reversalO
Thus, special loading of the slides in the slide ~ray is not
necessary,
~ ~ ~5;~
The fixad position slide gates 24 and 3S are con-
ventional in construction, configured and arranged 50 aB to
hold a ~lide firmly in position by clamping, typically at
one side toward the other side and against the face of the
slide, following movement of the slide from the tray into
the gate. After the slide has been projected, the slide is
lifted back up into iks original compart~ent in the slide
tray, typically while it i5 still clamped. The clamps on
the gate a~e then released to allow the movement of the next
slide into the gate.
In the embodiment shown, the arrangement of the
respec~ive projection optics systems 12 and 14 is such that
the hou~ing within which they are positioned i~ approximate-
ly the size of a conventional slide projector. The two fixed
ga~e~ ~4 and 36 in the embodiment shown are at an angle of
approximately 105 degrees relative to each o~h~r. ThiR ar
rangement h~s proven to be advantageous in th~ spacing of
the two projection optics sy tems, but also re~ults in a
relatively close side-by-side positioning of the respective
projection len~e~ thereof, with a relatively ~inimum dif~er-
ence ~approximately 1/2 inch) in the relative longit~dinal
po~ition thereof~
In an alternative arrangement, projection optics
~ystem 14 is arranged at an angle of approximately 65 de-
grees, similar to that shown in Figure 2. In thi~ arrange-
ment~ again referring to Figure 1, the mirror 38 i~ posi-
tioned on the other side o the projection path oE
projection optics sy tem 12, 80 that the projection path of
optic~ system 14 in effect cros~es the projection path of
optics system 12. In all such embodiment~, however, the
di~tance between the Plide and the projection lens in each
optics system i~ the ~ame if the ~ame projection len~e6 are
used in each optic system~ The two projection lenses 26
and 40 are supported such that ~hey can be mov~d toward and
away from each other to accomplish image separation, such as
di~closed in U. S, Patent No. 4,41-6,520 to Milo Kramer.
In Opera~iOD of the apparatus of Figure 1, slide
tray lS i8 rotated about a fixed vertical axis, without
rocking or other lateral movement, to service both projec-
tion optics systems. Tray 16 i~ driven at its rim by tray
drive element 420 The conventional 80 compartment slide tray
16 includes a plurality of downwardly projecting pin-like
alements at its periphery, which in one çmbodiment are
operated on by a gear portion of drive element 42 to pro-
vide the desired po~itive control over the movement of the
tray. Such a sy~tem can only ~e used, however, with the 80
compartment tray. In both the 80 compartment and the 140
compartment trayg the lower periphery o the slide tray ha~
a notch in it. Another tray drive embodiment includeQ a
drive ring which surrounds the peripheral edge of the tray
and has a projection which engages the notch in the tray.
The drive ring in turn is driYen by element 42, Such an
embodiment can be used with either the 80 or 140 compartment
tray. ~he ~equence of movement of the ~ray, as well as
additional disclosure concerning the tray driv~ ~ystem; will
2~ be di~cussed in more detail hereinafter.
Figure 2 shows an alternative embodiment u~ing
only one projection lens. A first projection optics system
50 includes a light ~ource 52, a heat f i 1 ~er 54, a condenser
lens 56 and a fixed slide gate 58. ~mage splitter 60 and
projection lens 62 are shared with the other projection
optic~ system 51. Projection op~ics sys~em 51 comprises a
light BOurCe 64, a heat filter 66, a condenser lens 68 and a
slide gate 70, in addition to image splitter ~0 and projec-
tion lPns 62. Projection optics ~ystem 50 define~ a
straight image projection path along the left side of the
projector; similar to that shown for the embodiment of Eig-
ure lo The image of optics system 50 is projected through
image 5pl itter 60 and through projection len~ 62 onto the
screen~
Image projection system 51 i~ po~itioned in the
embodiment shown such that its ~ixed slide gate 70 is at an
angle of approximately 65 degrees relative to ~lide gate 5B
in projection optic~ system 50. Thus, the im~ge projection
path of projection optics system 51 is angled, with the
image being reflected from image splitter 60 and then
through the single projection lens 6~ onto the creen. The
arrangement of Figure 2 is advantageous because it res~lts
in a reduced projector ~ize, and is less expen~ive and eas-
ier to operate.
Figure 3 ~ho~s a variation of the embodiment ofFigure 21 with only one light source. Two projection optics
system~ 72 and 74 are arranged ~imilarly to those shown in
Figure 2/ sharing an image splitter 76~ and a single projec-
lS tion lens 78. Both projection optics system share in addi-
tion a single light source 80, the light from which i pro-
vided to the respective projection optics system~ by means
of a 1 igh~ shutter 82 and replecting mirrors 84 and 8S.
Mirrors 84 and 86 could be "cold" mirrors, which pass most
of the infrared light while re~lecting the rest of the
light. I~ may be possible to eliminate ~he heat filter~ with
such an arrangeMentO
Light shutter 82 in the embodiment shown co~prises
two thin vertical plates supported in a track/ the plate~
2S having a xeflecting surace nearest light source 80. When
~hutter 82 i~ ope~, light from ~ource 80 i reflected off
mirror 84 into the path of projection optics system 74~
When light ~hutter 82 i~ closedl light from source 80 is
reflected off shutter 82, through a heat filter 90, and then
i~ reflected off m$rror 86 into projection optics sys~em
720 The arrangement of Figure 3 ha~ the advantage of elimi-
nating blackout flaps, and po3~ibly di~mer control circuitry
a~ well, which are necessary in more conventional lap-dis-
solve slide projectors.
, }~x~ .... . ....
~ 5~
Figures 4A, 4B and 5A, 5B show two embodiments for
moving thP slide tray between the two fixed gates in any of
the embodimen~s of Eigures 1-3c A conventional ciroular
~ray to be used with the present inven~ion includes a bottom
metal pan portion 100 and an upper slide recep~acle portion
102f typically made of plastic. The slide rec~ptacle portion
iB divided into compartments, typically 80 or 140, which
house the 31ide3. The tray i8 arranged such that the recep-
tacle is movable relative to the pan, ~hen the ~lide tray
ig po~itioned by the operator on a conventional slide pro-
jector, the pan is engaged so that in operation i~ remain~
fixed in po3ition while the receptacle rotates relative
thersto to acce~s the Rlldes.
In the conventional cs~mercial slide ~ray; the pan
ha~ one slot therein through which slide~ move between the
~lide receptacle and the slide gate in which ~lides are
projeoted. In a irst embodiment of the tray drive ~tructure
of the pre~ent invention; shown in Figuree 4A, 4B, the
conventional pan i9 modified by cutting another slo~ 101 in
the pan 100, ~lmilar in size and configuration to the orig-
inal ~lot, The additional ~lot i~ po~itioned in the pan 100
~uch that when the ~lide tray i~ positioned on the ~lide
pro~ector of the pre~ent invention, the two 810ts ar2 po~i~
tioned directly over the fixed ~lide gates. With this em-
bodiment, it is unnecessary to move the metal pan 100 during
operation of the slide projectorO The desir~d compartment in
the ~lide receptacle 102 is addres~ed by movement of th
receptacle 102 relative to the pan 100, a~ is the case for a
convantional slide projector O
As~ociated with each ~lide gate in the above em-
bodiment is a slide retainer or ~hoe and a ~lide lifter.
Referring ~pecifically to Figure~ 4A and 4B, which show~ the
~hoe and the lifter for one slide ga~e, the ~lide ~hoe in-
cludes an elongated arm 104 with a small rounded foot 106 at
the end thereof. ~n the embodimen~ shown~ arm 104 and the
foot 106 are aligned along the qame radiu~ as its asqociated
slide gate. The slide shoe i~ mounted such that it moves
bstween ~wo po~itions in a subs~antially radial direc~ion J
~hrough a piston-like action accomplished by means of a
~olenoid or similar mechanism ~not shown). It should be
understood, however, that the ~lide ho~ could be mounted
and move in other direction~, such as at a right angle or
tangentially to the slot, as opposed to radially.
Referring again to Figure~ 4~ and 4B, foot 106 and
th arm 104, in their retraGted position, are completely
free or removed from the slo$ 101 in the pan 100, which slot
i~ directly over the slide gate and the slide therein 108,
if any. In the retracted position, thP slide shoe has
moved radially towards the center of the slide tray. In the
extsnded po~ition oP the slide ~hoe, oot 106 i5 approxi-
mately at ~he midpoint of 510t 101, with a portion of foot
106 extending upward into slot 101 so that there exists a
continuous surface over a portion of ~he total length of the
slot~ In this position of the slide shoe, the receptacle 102
i free to rotate without the slide~ dropping through either
of the slots in the pan 100.
To load slides into the slide gates, recsptacle102 ~ rotated until tha compartment containing the desired
~lide to be projected i~ in ~egi~try with the fir~ ~lide
gateO The lifter 112 i in the raised position, having re-
25 mained ~here following the lifting o~ the previous slideback into its original compartment or having moved ~p with-
out a slide prior to the loading of the first slide into the
gateO The slide shoe in the embodiment shown is in the ex-
tende~ position when the receptacle moves and there is a
~lide in the slide gataO ~hen there iB no slide in the qlide
gatep the lifter i~ raised, and th~ slide shoe remains in
its retrac~ed position. The slide shoe and ~he lift0r are
arranged so that they can move as explained above without
interfering with each other~
,< ~,r. ' ! ' '
12
After the ~lide shoe is moved, if necessary, from
it~ extended position to its retracted position, the slide
to be projected re~ts on the lifter, and the slide in ef-
fect drops by gravity, but guided by the lifter, into th2
slide gate, clamped as explained above. There is al~o a
slide drop sensor in the ~orm of a light sen~or or the like
Inot shown) which provide~ an indication of the dropping of
a slide. Tn soms cases9 it will be undesirable to drop a
51 id~, and when the sensor iR ~ctuated, the 81 ide shoe can
be brought back to its extended position under the slide,
thereby preventing the ~lide from reaching the slide gate.
Af ter the 51 ide has raached the slide gate and
clamped, it is projected. The ~lide shoe is then moved back
to it~ extended po~ition. The lide recepkacle 102 is the~
moved until the compartment containing ~he desired ~lide to
be pro~ected i~ in rPgistry with the second ~lide gate. The
slide ~hoe for that gate is ln it5 extended position, it is
moved to its retracted po~ition~ as explained above, and
that slide then moves by gravity, with the lifter ~uppoLting
2~ it; into the slide gate, where it is ready to be projected
ollowing the projection of the ~lide already in the first
~lide gate. ~he slide shoe for the second ~lide gate is ~hen
moved back in it R extended po~ition.
~he receptacle 102 is then rota~ed back ~o that
the compartment originally containing tha fir~t desired
~lide i3 again ln reqistry with the first ~lide gate. When
the projection of that slide in the irst slide gate is
completed~ the slide ~hoe i8 retracted and ~he slide lifter
112 i~ opexated to lift the 81ide back up into the compart~
ment. ~he lift~r ~tays up, with the slide ~hoe retracted 9
and the receptacle is then rotated to acces~ the compart-
me~t containi~g the next slide to be projected with the
first ~lide gate. Thi~ process continue3 for each slide to
be projected in sequence between the two fi~ed gates. After
tne presentation is complete, the slide tray is removed from
the projec~or in conven~ional fashion.
13
Figures 5A and 5B shsw a ~econd embodimen~ for
driving the lide tray in the pre3ent invention. In this
embodiment~ th~ slide tray pan 120 ha~ only the one conven-
tional ~lot 1~1, and therefore is ldentical to a conven-
tional panO Conventional commercial circular ~lide tray~ canthus be used without any modification in this embodimen~v
~xt~nding slightly downwardly from th~ bottom ~urface of the
tray pan 120 i~ a dimple 122, in the center of which i~ an
opening 124~ The projection apparatu6 of the pre~ent inven-
tion include~ a small vertical pin 126 ~ee Figure 5B),mounted on a section of gear 128~ which i typically po~i-
.tionad in a clo3ed track or ~lst (~ot shown) in the projec-
torO The gear and pin structure i~ so positioned that when
the sllde tray i8 po~itioned on the projector, in it~ ref-
erence position, pin 126 extends upwardly through opening124, engaging the metal pan of the ~lide tray.
The gear ~ection 128 i~ driYen through a horizon-
tal arc by a gear 132, which in turn is driven by a motor
130. Thus, in thi~ embodiment, the tray pan 120 is po~-
20 i'~ively driven~ independently of the slide receptacle 129.In the ~equence o movements of th~ tray to load or unload
~lide8 from the r~spective fi~ed ~lid~ gates, the tray pan
120 is first moved 40 that the ~lot in the tray pan i8 in
registry with the particular ~lide gate which i~ ~o be
loaded/unloadedO
A ~ingle ~lide sho~ in the embodiment shown~
moves with the tray pan in an ~xtended po~ition, to block
any po33ible movement of ~lide~ through the ~lot., Alterna-
tively, the projector could include a ~erie~ of flxed shoes
along the path of the slot between the two slide gates whlch
operate in ~equ~nce to provide continuou~ support benea~h
the 310t a~ it move~, or the tray could be moved as a com-
plate unit with an empty compartment above the ~lot. Typi--
cally~ but not neces~arily, th~ ~lide receptacle moves with
35 the tray pan when the tray pan i~ moved to po~ition the slot
th~r~in in registry with a ~lide gate. When the ~lot i
14
po~Qitioned, the re~eptacle i~ then moved independently to
acce~s the desired compartment. The shoe i~ then retracted
and the slide may be moved.
More ~pecifically with respect to the operational
sequence, a~suming that the re~Qpective slide gates are
5 initially both empty, the slide ~ray is first positioned by
the operator in it~ reference po3itlon on the projector. The
tray pan and the r~ceptacle are then rotated as a unit a~
explained above until the ~lot 121 in the pan 120 i3 in
registry with the first slide gate. The slide receptacle 129
is th~n moved alone until the compartment containing the
fir~t slide to be projected i~ in registry with the ~lot 121
and the first sl1de gate. The li~ter ~not shown) i5 Up a~
thi~ point. ~he slide shoe (not shown) is then retracted,
opening the ~lot, and the first slide move~ down into the
15 slide gate by gravity, reQting on the lifter. The ~lide ~hoe
ig then extended. ~he tray pan a~d the tray receptacle are
then moved as explained above to load the second slide into
th~ ~econd slide yate.
The tray pan and the xeceptacle are then rotat2d
20 back together to the point where the 510t 10l i~ above the
firat slide gate. The slide receptacle i~ then rotated by
itself to the point where the compartment originally con-
taining slide one iQ in registry with the slot 101 and the
~lid2 gate, The ~hoe is then retracted and the lifter i5
25 actuated, moving the slide back up into the compartment.
Tha lifter remains in the raised po~ition. The ~lide recep-
tacle i~ then rotated so that the compartment containing the
third slide to be projected i5 in registry with the ~lot and
the 81 ide gate, and the slide lowered into the ga~e for
3û pro~ection. Thi~ proceQ~ continue~ until the 31ide prl3senta-
tioT~ i~ completed~
The ~lide receptacle will typically have either 80
or 1~0 compartment~, The 80 compartment receptacle typically
includes a plurallty of lug~ or pi~8 which depend downwardly
from the lower peripheral edge of the ~ray, one lug for each
compar~ment. In one embodiment, ~he receptacle i3 then
driven a~ shown in ~igure 5Br with gear 112 ma~ing with the
lug~ on the tray and mo~or 114 driving the gear. The 80 and
the 140 position receptacles both have a single notch in
5 their lower peripheral surface. In another embodiment, drive
ring surrounds the lower peripheral edge of the tray, with a
projection which extends into the notch in the tray. Figure
6 ~hows a portion of a tray receptacle 140, th~ notch in the
lower edge thereof 142~ and the drive ring with its projec-
10 tion 1~4. The drive ring is rotated by a gear 146, which i8driven ~y a motor 148. Such a driYe ~tructure for the 8Q
compartment tray i5 an alternative to the s~ructure des-
cribed above~
Thus, an apparatus has been de~cribed which pro-
15 vide3 a multiple i~age slide prcjection capability with
fixed slide gate~ using a conventional circular slide ~ray
which is rotated about a fixed central vertical axi~
though a preferred embodiment of the invention has been
disclo~ed herein for illustration, it should be understood
that various changes, modifications and ~ubsti~utions may be
incorporated in such embodiment without depar~ing from the
spirit o~ the invention a~ defin~d by the claims which fol-
low~
