Micro image cassette and viewer

An improved filmstrip-carrying cassette, the filmstrip carrying thereon microimages arranged in rows and columns, and a viewer for illuminating, projecting, enlarging and reading on a display screen a selected one of the microimages is provided, using a pair of transparent plates to engage a selected portion of the filmstrip on opposite sides to hold same in a precise focal plane for properly illuminating and projecting the selected microimage. The filmstrip has great width to accommodate multiple rows of microimages, and motor means operate to transport the filmstrip selectively in opposite directions to quickly locate the column in which the desired microimage is located. The cassette is carried by a viewer-mounted carriage that is manually reciprocable along a track, so as to traverse the column in seeking the desired microimage. The transparent plates are separated simultaneously with the energizing of the motor means to permit unfettered movement of the filmstrip. In one form of construction, the transparent plates are carried by the cassette. In a preferred form, the cassette carries one transparent plate, and the other plate is carried by the viewer's carriage; the motor means provides selectively fast or slow transport, and the transparent plates are caused to separate only during fast transport, to provide visual coordination for locating the selected microimage with the slow transport of the filmstrip. A modular construction for the light projecting portion of the viewer provides for simplicity of adjustment and servicing.

FIELD OF THE INVENTION 
This invention relates to microfilm cassettes and viewers for illuminating, 
enlarging, projecting and displaying selected frames of the microfilm on a 
viewing screen and more particularly to a novel cassette and viewer 
specially adapted to position microimage frames for projection in a 
pre-selected focal plane. 
BACKGROUND OF THE INVENTION 
The printing of microimages on microfiche cards and the use of viewers for 
illuminating, enlarging, projecting and displaying selected frames of the 
cards on a viewing screen is well known in the art. The printing of 
microimages on filmstrips and the use of viewers for illuminating, 
enlarging, projecting and displaying selected frames of the filmstrip on a 
viewing screen is also well known in the art. 
It is further known to house the filmstrip on a cassette for presenting a 
length of flexible film for projection and display. By storing information 
on a microfilmstrip, an entire book or a lengthy catalog of parts may be 
stored on a single compact cassette. The prior art, as evidenced by U.S. 
Pat. No. 3,700,321, has fixedly located a generally U-shaped cassette with 
a microimage holding bight portion window between an illuminating system 
and a lens assembly to precisely align a selected microimage with the 
optical system of the viewer. 
There exist countless situations in which it would be advantageous to store 
a greater number of microimage frames on a single filmstrip. For example, 
it is desirable to store a full set of volumns of a given reference or the 
entire inventory of a given company within a single cassette. To this end, 
previous patents such as U.S. Pat. No. 3,319,517 have provided a cassetted 
filmstrip, the transverse dimension thereof being great enough to include 
a plurality of rows of microimages so as to substantially increase the 
amount of printed matter that can be stored in a single cassette. 
As the width of the cassetted filmstrip was increased, it became necessary 
to modify existing viewer-cassette assemblies to accept, project and 
display selected microimage frames regardless of their longitudinal or 
transverse location on the filmstrip. Early microfiche viewers provided 
for manual movement of a fiche supporting table in both transverse and 
longitudinal directions to align a selected microimage between a lower 
source of illumination and an upper projection lens system. As technology 
advanced and 8 and 16 mm cassetted microfilm supplanted microfiche, there 
was no need to traverse the width of the film. Because the transverse 
dimension of the filmstrip was relatively small, its full width could be 
projected onto the viewing screen. 
With the continuing development of microfilm technology came the advent of 
wider microfilmstrips. As the full filmstrip width could no longer be 
displayed on the viewing screen at one time, it became necessary to 
incorporate a transverse filmstrip scanner into the viewer assembly. One 
type of scanner was developed in U.S. Pat. No. 3,319,517. The scanner 
basically included a transport assembly on which the film spools were 
secured for slidable movement relative to a lens projection assembly. 
However, the filmstrips of that and other prior art devices were not 
housed in a cassette and therefore were easily scratched and otherwise 
injured by the constant human handling necessary to prepare the filmstrip 
for projection. 
It is accordingly a major purpose of the present invention to provide a 
cassette for housing and transporting filmstrips having transverse 
dimensions great enough to house a large number of microimage frames 
thereacross and to provide a viewer having a movable carriage in which the 
cassette is placed for scanning and projecting those transverse microimage 
frames. 
Of course, the filmstrip length is many times greater than its width. With 
this in mind, prior viewer systems incorporated drive assemblies for the 
selective longitudinal transportation of the filmstrip within the 
cassette. However, none of the previous systems employed a movable 
carriage for transversely scanning the width of a cassetted filmstrip. 
It is yet another object of the present invention to provide a viewer 
having a movable carriage for holding a cassette and in which the drive 
means for transporting the filmstrip and presenting selected longitudinal 
microimage frames for projection are mounted on the carriage for movement 
therewith. 
Many previous viewers for projecting and displaying filmstrips such as the 
viewer shown in U.S. Pat. No. 3,319,517 have tensioned the filmstrip over 
a plastic plate so as to hold the filmstrip in the focal plane of the 
objective projecting lens. But the constant contact between the filmstrip 
and the plate often caused scratching or other injury of the filmstrip 
which seriously interfered with the projected image because of the optical 
magnification occasioned by the viewer. Other viewers held the filmstrip 
in the focal plane by supporting the longitudinal edges thereof in the 
area about the optical path of projected light. Of course, as the width of 
the film increased, such support means failed to adequately maintain the 
entire filmstrip width under sufficient tension, thereby having sections 
thereof buckle out of the focal plane. 
One additional object of the present invention is to provide a pair of 
transparent glass plates between which a filmstrip, regardless of width, 
may be disposed in non-contacting positions for longitudinal movement 
without contacting either plate and which plates cooperate with a lens 
assembly housed in the viewer to clamp the entire width of the filmstrip 
between the plates into a focusing plane only when the filmstrip is not 
being moved. 
A further object of this invention is to provide a filmstrip-carrying 
cassette and viewer construction, of the type using opposed transparent 
plates for holding a portion of the filmstrip of the cassette in a focal 
plane, wherein one of the plates is carried by and constitutes part of the 
cassette and the other of the plates is carried by the viewer's carriage 
which supports the cassette. 
And another object of the invention is to provide a filmstrip-carrying 
cassette and viewer construction, wherein the transport of the filmstrip 
within the cassette may be selectively controlled for fast or slow 
transport, and wherein the cassette's filmstrip is caused to be free of 
restraints during fast transport, but is, during slow transport, kept in 
such a focal condition that the slow transport may be simultaneously 
coordinated with viewing the projected microimage so as to afford 
efficiency in locating the desired microimage to be projected and viewed. 
More specifically, the filmstrip of the cassette that is normally clamped 
between two transparent plates to be held in a focal plane, is to be 
completely released during fast transport, but is still to be held 
substantially in the focal plane during slow transport. 
And still a further object of this invention is to provide a modular 
construction for the light projecting portion of the viewer, which 
provides for simplicity of adjustment and servicing of the parts thereof. 
These as well as further objects and advantages will become apparent from 
the detailed explanation of the invention that is provided in the 
description and claims, and is illustrated in the accompanying drawings. 
BRIEF DESCRIPTION OF THE INVENTION 
A cassette houses spaced spools upon which portions of an elongated 
microimage bearing filmstrip are wound. The filmstrip is longitudinally 
movable within the cassette in incremental amounts for traversing an 
elongated filmstrip passageway. An aperture is formed through the 
passageway for permitting projected light to pass through a selected 
portion of the filmstrip for enlarging and displaying one of the 
longitudinally and transversely-extending microimage frames. Apparatus is 
provided for positioning the selected microimage frame in a filmstrip 
focusing plane. The apparatus includes a first transparent plate located 
in the path of projected light but spaced to one side of and away from the 
plane formed by the filmstrip traversing the passageway, a second 
transparent plate located in the path of projected light but spaced on the 
opposite side of and away from the filmstrip traversing plane and an 
assembly operable to separate the first and second plates prior to 
filmstrip movement through the passageway and also operable for clamping 
the selected filmstrip portion between the plates in the filmstrip 
focusing plane after a selected portion of the filmstrip has been moved 
into and stopped in the path of projected light through the passageway 
aperture. 
A viewer operatively positions the filmstrip separation-clamping assembly 
in an upper module which is spaced from the base of the viewer. In the 
space between the module and the base, a filmstrip-driving carriage is 
movably suspended for translation along tracks on the underside of the 
module. The cassette is mounted on the carriage for manual translational 
movement relative to the path of projected light to present a selected 
column of microimage frames into the path of the projected light and the 
carriage is adapted to move the filmstrip through the cassette passageway 
to present a selected row of microimage frames into the path of the 
projected light. 
The separation-clamping assembly cooperates with the first and second 
transparent plates to present selected microimage frames and includes a 
slidably-mounted lens plate which normally rests on and clamps the 
filmstrip between the glass plates in the focusing plane. When it is 
desired to transport the filmstrip through the cassette passageway, a 
viewer drive assembly control is activated to energize a solenoid which 
separates the glass plates and releases the filmstrip for movement 
therebetween. 
In the second, or preferred, form of the invention, the movement of the 
filmstrip in the cassette is caused to be fast or slow in opposite 
directions, and controls therefor are provided on the viewer's carriage 
which carries the cassette. One of the two transparent plates for 
positioning the desired portion of the filmstrip in the focusing plane is 
carried by the viewer's carriage, and gravity is relied upon to effect 
clamping the selected filmstrip portion between the plates in the 
filmstrip focusing plane. The controls for effecting fast transport of the 
filmstrip are arranged to cooperate with the carriage-carried transparent 
to effect separation of the plates simultaneous with initiation of fast 
transport. 
In the module construction for the light-projecting portion of the viewer, 
the light source, and light intensity enhancing mirror are pre-assembled 
on a structure that may be selectively removed for servicing of those 
units, and when pushed back into assembled condition, effects the 
necessary electrical hook-up with the source of power.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, one form of the improved microfilm cassette 
is shown in FIGS. 1-9 and generally shown as 10, with the improved 
microfilm viewer generally indicated as 50. 
The First Form Of The Invention 
The cassette 10 houses a pair of conventional, spaced annular spool means 
12, upon which an elongated microimage bearing filmstrip 14 (FIG. 4) is 
wound. The cassette 10 includes an elongated filmstrip passageway 16 
formed by the horizontal path of travel of the filmstrip 14 as it 
traverses the distance between the spaced spool means 12. A pair of idling 
rollers 17 are rotatably mounted within the cassette 10. The filmstrip 14 
is trained over the idling rollers 17 for selected incremental movement 
through the elongated filmstrip passageway 16. The path of the filmstrip 
14 as it traverses the passageway 16 between the pair of idling rollers 17 
defines a filmstrip traversing plane 18 (FIG. 6). 
The elongated passageway 16 includes a transverse aperture 20 for 
permitting projected light to pass through a selected portion of the 
filmstrip 14 for greatly enlarged and focused display of the microimage 
that is provided on the selected portion of the filmstrip. First and 
second generally rectangular transparent, glass plates, 22 and 24 
respectively, are disposed within the transverse aperture 20 parallel to 
each other and filmstrip 14. The upper plate 22 is located in the path of 
projected light and spaced to one side of and away from the filmstrip 14 
in its filmstrip traversing plane 18 while the lower plate 24 is also 
located in the path of projected light but spaced on the opposite side of 
and away from the filmstrip 14 in its filmstrip traversing plane 18. 
With specific reference to FIG. 6, filmstrip 14 can be seen to be in its 
filmstrip traversing plane 18 wherein it is disposed parallel to the upper 
plate 22 and the lower plate 24. The lower plate 24 is fixedly mounted 
relative to the aperture 20 in the filmstrip passageway 16. The upper 
plate 22 is of slightly greater width than both the lower plate 24 and the 
aperture 20 such that the edges 25 of the aperture 20 retain the upper 
plate 22 within the aperture 20 and limit the upward movement of the upper 
plate 22. The lower plate 24, being fixedly mounted, limits the downward 
movement of the upper plate 22. Stop mountings 26 are provided beneath 
each corner of the upper plate 22 and serve to support upper plate biasing 
springs 28. The springs 28 normally bias the upper plate 22 into an 
uppermost position against the edges 25 of the aperture 20. Downward 
pressure on the upper plate 22 acts against the bias of springs 28 to move 
the plate 22 downwardly, through the filmstrip traversing plane 18, to 
clamp the filmstrip 14 against the lower, fixed plate 24 so as to lie in 
and define a filmstrip focusing plane. When the cassette 10 is placed in 
operative position in the microfilm viewer 50 and the filmstrip 14 is 
clamped between upper plate 22 and lower plate 24, the filmstrip 14 
thereby lies in the proper focal plane for illumination, enlargement and 
display on a viewing screen. 
In the first embodiment, the cassette 10 is generally U-shaped and includes 
a pair of leg enclosure means 30 connected by an intermediate bight 
portion 32. The bight 32 is defined as that portion of the cassette 
between the leg means 30 in which the filmstrip 14 is trained over idler 
rollers 17 to locate the filmstrip traversing plane 18. The front and back 
sides, 34 and 36, of the enclosure means 30 rotatably support the spool 
means 12 for winding the filmstrip 14 thereon and rotatably support the 
idler rollers 17 for training the filmstrip 14 thereover. Since the 
cassette 10 of the present invention does not grip the longitudinal 
filmstrip edges, the idler rollers 17 must be at least as wide as the 
filmstrip being used to support the filmstrip 14 in its traversing plane 
18. 
The Viewer 
The microfilm viewer 50 of this invention comprises several major 
components, each of which is being described in detail below. 
The Module 
The viewer 50 includes an upper module 52. The module 52 is spaced by 
vertical support means 54 from a viewer supporting base 56. The module 52 
is enclosed by side panels 58 and 60, top panel 62, back panel 64 and a 
substantially transparent microimage display and viewing screen 66. The 
precise configuration of the respective panels is not critical, but in the 
preferred embodiment they form a generally rectangular container. The 
bottom panel 68 of the module 52 includes a light ray window (not shown) 
formed by cutting away a portion of the bottom panel 68. The bottom panel 
68 also has a pair of spaced, parallel, carriage-mounting tracks (not 
shown) constructed thereon and extending along at least part of the depth 
of the module between the viewing screen 66 and the back panel 64. 
The bottom panel 68 of the module 52 has an elongated slot 63 extending 
therethrough. An electrical control panel 65 is housed adjacent the back 
panel 64. Wires from the control panel 65 are bound together to form an 
"umbilical cord" 67 passing from the module 52 to a cassette carriage 74 
for reasons explained below. 
The Enclosure 
Centrally located in the space between the module 52 and the base 56 and 
resting on the base 56 in a filmstrip illuminating enclosure 70 having a 
light passing opening 71 formed in its upper surface 72, directly below 
and aligned with the light ray window in the bottom panel 68 of the module 
52. The height of the enclosure 70 is less than the height of the space 
between the base 56 and module 52. 
The Carriage 
A cassette-driving and translating carriage 74 includes an upper, generally 
horizontally-disposed frame 76 and filmstrip driving casing 78. The casing 
78 is generally rectangular in shape and depends from one side of the 
horizontal frame 76. A pair of elongated filmstrip-winding spindles 80 
extend outwardly from the front side of the casing 78 on opposite sides of 
the enclosure 70 and are arranged to slidably enter the bores of the 
annular spools 12 and to effect driving connection therewith through the 
medium of one-way sprag clutches not shown, but well known in the art, 
carried by spools 12. Secured to the side of the horizontal frame 76 
opposite the casing 78, a pair of elongated runners (not shown) are spaced 
so as to engage the track on the underside of the bottom panel 68 and 
support the carriage 74 for translational movement relative to the viewer 
module 52 and the enclosure 70. 
The carriage 74 translates between a first rearward position in which the 
frame 76 extends only slightly forwardly of the plane of the viewing 
screen 66 and a second forward portion in which the frame 76 extends 
substantially forwardly of the plane of the viewing screen 66. The actual 
length of travel of the carriage 74 on the tracks is not critical, but the 
travel must be at least as long as the width of the filmstrip wound in the 
cassette 10 so that the entire width of the filmstrip can pass over the 
opening 71 in the filmstrip illuminating enclosure 70 for projection onto 
the viewing screen 66. In this regard, the length of the slot 63 through 
the bottom module panel 68, must also be of sufficient length to allow the 
carriage 74 to traverse the length of the tracks. 
The motors and gearing housed within the casing 78 are not picture because 
the drive system used to longitudinally move the filmstrip 14 of the 
present invention closely approximates the motors and gearing fully 
illustrated and explained in U.S. Pat. No. 3,785,728. It should be 
understood that variations and modifications of the drive mechanism may be 
made without departing from the spirit and scope of this invention. The 
drive system is controlled by the umbilical cord 67 extending from the 
control panel 65 through the slot 63 and attached to the motors housed 
within carriage 74. 
A variable speed control 82 is positioned at the center and front of the 
horizontal frame 76 and extends forwardly thereof. By displacing the 
control to the right, the right-hand spindle 80 is rotated to rotate the 
spool 12 in the filmstrip cassette 10 and thereby move the filmstrip 14 to 
the right, whereas displacement of the control 82 to the left similarly 
effects filmstrip displacement in the left-hand direction. The control 82 
is connected to a rheostat for varying the speed of spindle rotation. The 
further to the right or to the left the control 82 is shifted from its 
normal inoperative, centrally located position, the greater is the speed 
of spindle rotation in that direction. 
A centrally elongated, transversely and longitudinally extending cut-out 
(not shown) is located on the frame 76 so as to be aligned with the 
opening 71 in the top surface 72 of the enclosure 70 when the carriage 74 
translates along the module tracks. The frame 76 further includes a pair 
of handles 84 on opposite sides of the speed control 82 for use in 
manually moving the carriage 74 relative to the module 52 and enclosure 
70. A lock 84 may be provided on the frame 76 to fasten the carriage 74 in 
its rearward position when not being used so as to prevent cassette theft 
and unauthorized viewer manipulation. 
The Optical System 
Viewing FIG. 9, the optical system of this invention will now be described. 
The enclosure 70 includes a source of illumination such as light 86 behind 
which a curved reflector 88 directs the light rays emanating from the 
source of light 86 to impinge on a dichroic folding mirror 90 which 
filters out infrared rays and directs the light rays upwardly through a 
condensing lens 92 and through the openings 71 in the upper enclosure 
surface 72. A heat absorbing filter 94 as well as other heat venting 
means, may be included within the enclosure 70 to relieve the temperature 
build-up in the confines of the enclosure 70. 
Because the height of the enclosure 70 does not extend upwardly far enough 
to reach the module 52, a filmstrip 14 may be positioned between the 
opening 71 in the upper surface 72 of the enclosure 70 and the cut-out in 
the horizontal carriage frame 76. The projected light rays then pass 
through the selected portion of the filmstrip trained over the enclosure 
70 and enter the module 52 via the light ray window formed in the bottom 
module panel 68. 
The image bearing light rays pass through an objective projecting lens 96 
and are directed from a first folding mirror 98 to a second folding mirror 
100 to the viewing screen 66 for display. It is to be understood that 
variations in the size and attitude of the viewing screen and the 
orientation of the folding mirrors can be made without departing from the 
scope of the invention. It is however, significant that the optical system 
is fixed within the viewer 50 and that it is the filmstrip that moves 
relative to the fixed optical system. 
The Separation-Clamping Means 
Separation-clamping means 102 provided on the bottom panel 68 of the viewer 
module 52 are operable to move the filmstrip 14 through the filmstrip 
passageway means 16 for effecting separation of the upper and lower 
transparent plates 22 and 24. The separation-clamping means 102 are 
further operable after a selected portion of the filmstrip 14 has been 
moved into and stopped in the path of the projected light emanating from 
the enclosure 70, for clamping the selected filmstrip portion between the 
upper and lower plates, 22 and 24, in the filmstrip focusing plane. 
The separation-clamping means 102 comprises lens assembly means 104 and 
plate separation means 106. 
The Lens Assembly 
The lens assembly means 104 includes generally rectangular plate means 108 
for attaching the lens assembly means 104 to the module 52 so as to be 
positioned directly above the upper transparent glass plate 22 in the 
cassette aperture 20 and the light passing opening 71 in the upper surface 
72 of the enclosure 70. The attachment plate 108 includes a large 
centrally positioned aperture 110 and a pair of smaller apertures 112 
adjacent opposite side edges thereof. A pair of stop sleeves 114 depend 
from the underside of the attachment plate 108 with the bore of the stop 
sleeves 114 aligned beneath the small apertures 112. 
An upper generally rectangular lens plate 116 includes a centrally 
positioned aperture 118, an eccentric receiving notch 120 on the underside 
thereof and a pair of rods 122 secured at one of their ends to and 
depending from the opposite side edges of the upper lens plate 116. The 
diameter and location of the rods 122 are such that they may be slidably 
received in apertures 112 and the central bore stop sleeves 114. 
A lower, generally rectangular lens plate 124 also includes a centrally 
positioned aperture 126 and secures the other ends of rods 122 at its 
opposite side edges. When the attachment plate 108 is securely mounted in 
the bottom of upper module 52 of the viewer 50, the upper and lower lens 
plates 116 and 124 are movable en masse as the rods 122 reciprocally slide 
in the apertures 112. When so mounted, the apertures 110, 118 and 126 are 
positioned in vertical alignment with each other and with the light 
passing opening 71 in the upper surface 72 of the enclosure 70, the 
aperture 20 in the cassette 10 and the light ray window in the bottom 
panel 68 of the viewer module 52. The downward motion of the lens plates 
116 and 124 is limited by the bottom surface of the stop sleeves 114. 
An elongated lens-sleeve-receiving-casing 128 is secured to the underside 
of the upper lens plate 116 for movement therewith. The outer diameter of 
the lens casing 128 is smaller than the diameter of the attachment plate 
aperture 110 so that the lens casing 128 is free to slide through the 
aperture 110 as the upper and lower plates 116 and 124 reciprocate. The 
lens casing 116 includes a centrally threaded bore 130 therethrough and a 
notch 132 at its upper plate contacting edge. When the lens casing 128 is 
secured to depend below the upper plate aperture 118, the lens casing 
notch 132 and the upper plate notch 120 define an eccentric-receiving 
opening 134. 
An elongated lens sleeve 136 has at its lower end an enlarged-knurled 
flange 138. The lens sleeve 136 is externally threaded at 140 for 
reception in the internally threaded bore of the lens casing 128. The 
knurled flange 138 has a diameter greater than the diameter of the 
attachment plate aperture 110 so that the lens sleeve 136 must be inserted 
into the lens casing 128 from below the lens attachment plate 108. Even 
when so inserted, the lens sleeve 136 is reciprocally movable with the 
lens casing 128. A projection lens 142 is mounted on lens insertion means 
144 to be held within the bore 146 of the lens sleeve 136 is any desirable 
manner. 
A polycarbonate ring 148 may be secured on the bottom side of the lower 
lens plate 124. The ring 148, being fabricated from a soft, resilient 
material, will not scratch or otherwise injure a surface with which it 
makes contact. 
Although not shown, an oil stone bearing washer may be inserted in the 
eccentric-receiving notch 120 formed on the underside of upper lens plate 
116. The purpose of the oil stone washer is to soften the sound of impact 
of the eccentric as it contacts the upper plate 116. 
The Separation Means 
The separation means 106 includes a solenoid 150, an eccentric shaft 152 
and an eccentric 154 at the end of the shaft 152. The shaft 152 is 
rotatably secured at one end to the solenoid 150. The opposite end of the 
shaft 152 is placed within the eccentric-receiving opening 134 formed by 
the lens casing 128 and the upper lens plate 116. The solenoid 150 is then 
fastened to the bottom of the viewer module 52, whereby activation of the 
solenoid 150 rotates the eccentric 154 within the eccentric opening 134 
such that it strikes the upper plate notch 120, causing the upper and 
lower lens plates 116 and 124 and parts mounted thereon to slide upwardly 
from their normal downwardly, gravity-biased position. 
Operation 
The operation of the microfilm viewing system of the present invention will 
now be described. The cassette 10 is snapped onto the carriage 74, in the 
space between the upper viewer module 52 and the viewer base 56, such that 
the carriage drive spindles 80 engage the cassette spools 12 for rotation 
thereof. In the preferred embodiment, the cassette 10 is generally 
U-shaped and the spool enclosure leg means 30 are positioned on opposite 
sides of the enclosure 70. The window 20 in the bight portion 32 which 
includes upper and lower glass plates 22 and 24 is positioned to be 
directly aligned with the opening 71 in the top surface 72 of the 
enclosure 70, the cut-away portion of the carriage frame 76, the slot in 
the bottom module panel 68 and the apertures 124, 110, 118, in the lens 
plates 124, 108 and 116. In this manner an optical light path is formed 
from the enclosure 70, through the opening, the cassette window 20, the 
carriage frame 74, the bottom module plate 68 and into the objective 
projection lens 142. 
In the normal, unactivated position of the glass plate separation-clamping 
means 102, the weight of the lens plates 118 and 124, the lens sleeve 136 
and the lens casing 128, acting under the influence of gravity, slides the 
separation-clamping means 102 downwardly. In this downward position, the 
polycarbonate ring 148 rests on and depresses the upper glass plate 22 
against the bias of the springs 28 to move the filmstrip 14 from the 
filmstrip traversing plane 18 to the filmstrip focusing plane in which the 
filmstrip 14 is clamped between the upper and lower glass plates 22 and 24 
at the focal point of the projection lens 142. In this position the 
carriage 74 may be translated along the tracks to select a microimage 
frame from a column of frames printed on the filmstrip width. 
When it is desired to move the filmstrip 14 longitudinally the control 82 
is pushed in the right or left-hand direction to correspondingly move the 
filmstrip 14. The further to the right or left the control 82 is shifted, 
the greater is the speed of spindle rotation. The solenoid 150 is 
energized simultaneously with activation of the control 82. Energization 
of the solenoid 150 rotates the eccentric 154 at the end of eccentric 
shaft 152 within eccentric opening 134 to contact the bottom of the upper 
lens plate 116 and thereby lift the glass plate separation-clamping means 
102 upwardly. As the separation-clamping means 102 moves upward, the upper 
glass plate 22 is also allowed to move upwardly under the bias of the 
spring 28. This serves to release the filmstrip 14 for longitudinal 
movement through the transverse passageway aperture 20 in the filmstrip 
traversing plane 18 to present a selected row of microimage frames in the 
aperture 20. 
It is thus seen that the use of the control 82 and the traversing carriage 
74, presents a selected microimage frame from any filmstrip row or column 
into the path of projected light for illumination, enlargement and display 
on the viewing screen 66. 
THE SECOND FORM OF THE INVENTION 
In the description of the preferred embodiment of the invention which 
follows, elements substantially identical to those elements described in 
the First Form Of The Invention, are given like reference numerals with a 
prime (') added. 
Referring now to the drawings, major elements of the second form are shown 
generally in FIGS. 10-17 in which the microfilmstrip cassette is depicted 
generally at 10' and the microfilmstrip viewer is generally indicated at 
50'. 
The Cassette 
The cassette 10' is generally U-shaped, the legs of the U being formed by a 
pair of box-like enclosures 30' between which extends the U's bight that 
includes cross bars 11 and provide support for a transparent glass plate 
22' carried by the cassette 10'. The oppositely facing side walls of the 
two enclosures are apertured to provide passageways 16, above the plate 
22', through which the filmstrip 14' passes from one to the other of the 
enclosures 30'. The filmstrip 14' is moved from a pair of spool means 12' 
trained over spaced idling rollers 17, FIG. 4, located within the 
enclosures 30'. The idling rollers 17 operate to define a filmstrip 
traversing plane as the path the filmstrip 14' moves through in passing 
between the enclosures 30', the path being spaced above of and not 
contacting the upper surface of the transparent plate 22'. 
The presence of the transparent plate 22' supported only at its ends in the 
bight portion of the cassette 10' provides a transverse aperture means 20' 
for permitting projected light to pass through the plate 22' and a 
selected portion of the filmstrip 14'. The plate 22' is fixed by the 
cassette 10' at an attitude parallel to, but below the horizontal path of 
travel of the filmstrip 14' when in its filmstrip traversing plane. More 
specifically, the transparent plate is arranged to lie, at each end, in a 
recess and on a shoulder 15 defined in the cross bar 11. 
Referring to FIG. 15, the filmstrip 14' is shown in the filmstrip 
traversing plane wherein it is disposed parallel to, but spaced above the 
plate 22'. There is sufficient "give" in the coiled portions of the 
filmstrip located in the enclosure 30' to permit the filmstrip 14' to be 
moved downwardly until its bottom surface 14' engages the top surface of 
the plate 22'. With the cassette 10' operatively positioned in the viewer 
50' and the filmstrip 14' engaging the transparent plate 22', the 
filmstrip 14' lies in the proper focal plane for illumination, projection 
and display on the viewer's viewing screen. 
The Viewer 
The major components of the microfilm viewer 50' are described in detail 
below. 
The Enlarging And Viewing Module 
The viewer 50' includes an upper enlarging and viewing module 52' being 
spaced by upright support sides 54' above a viewer support base 56'. The 
module 52' is enclosed by side panels 58' and 60', top panel 62', back 
panel 64', a translucent microimage display and viewing screen 66', and a 
bottom panel 68'. 
The bottom panel 68' of the module 52' includes a light projection window 
(not shown) formed by cutting away a portion of that panel. The bottom 
panel also has a pair of spaced, parallel, carriage-mounting tracks (not 
shown) constructed thereon and extending along at least part of the depth 
of the module between the viewing screen 66' and the back panel 64'. 
The bottom panel 68' of the module 52' further has an elongated slot 63, 
see FIG. 5, extending therethrough. Electrical controls are housed 
adjacent the back panel 64' and wires from the electrical controls are 
bound together to form an "umbilical cord" 67 and pass from the module 52' 
to a cassette carriage 74'. 
The Light Projecting Enclosure 
Centrally located in the space defined vertically between the module 52' 
and the base 56', and mounted on the base 56' is a light projecting 
enclosure 70', see FIG. 1, having a light passing opening 71' formed in 
its upper wall 72', directly below and aligned with the light ray window 
in the bottom panel 68' of the module 52'. The height of the enclosure 70' 
is less than the height of the space between the base 56' and the module 
52'. 
The enclosure 70' further includes side walls, 73 and 75, rear wall 77, 
base plate 79 and front wall 81. The walls may be provided with elongated 
ribs such as 83, FIGS. 16 and 17, on their exterior surface from which to 
dissipate heat generated within the enclosure 70'. The front wall 81 is 
secured to the base plate 79 by a pair of screws 104 having enlarged, 
knurled heads 85. The heads 85 may be rotated to firmly engage a pair of 
spaced, tubular extensions 93 of base plate 79. A tight connection is 
important to insure proper conduction and dissipation of heat from the 
front wall 81. Mounted on the base plate 79 is a light socket 90 which 
receives a high intensity light bulb 86'. Light rays from the bulb 86' are 
reflected by a concave mirror 88' that is held in position on an upright, 
base-mounted frame 95, by means of a leaf spring 97. The light socket 90 
receives power via wires 96 which connect to an electrical 
power-receiving, socketed receptacle 98. The socketed receptacle 98 is 
adapted to receive power-transmitting prongs secured within the enclosure 
70'. 
The front wall 81 and base plate 79, with the illumination and projection 
elements mounted thereon, constitute a cartridge that is selectively 
removable from the remainder of the enclosure 70'. Because the light 
projection means are removable as a cartridge, the illumination and 
projection elements may be replaced, or adjusted for alignment, by simply 
removing the cartridge to a convenient location for work thereon. Upon 
re-insertion of the sub-assembly, the socketed receptacle 98 receives the 
electrical male power prongs to energize the light bulb 86'. 
The Carriage 
The carriage 74' includes an upper, generally horizontally disposed tray 
76' and a drive casing 78' depending from the rear portion of the upper 
tray 76'. A pair of elongated filmstrip winding spindles 80' extend 
forwardly from the front wall of the carriage drive casing 76' and on 
opposite sides of the projection enclosure 70' and are shaped to slidably 
enter the bores of the annular spools 12' and to effect driving connection 
therewith through the medium of one-way spring clutches. Also secured to 
the front wall of the drive casing 76' above and below each spindle 80', 
are a pair of elongated stop means 105 that are to be abutted by the 
cassette 10' to properly position the cassette 10' on the carriage 74'. 
Secured to the top side 130 of the tray 76' are a pair of elongated track 
gripping members 102, spaced so as to engage the track on the underside of 
the bottom panel 68' and to thereby support the carriage 74' for back and 
forth translational movement relative to the viewer module 52' and 
projection enclosure 70' . 
The carriage 74' translates between a first, rearward, position shown in 
broken lines in FIG. 10, in which the drive casing 78' extends rearwardly 
of the plane of the back panel 64', and a second, forward, position, shown 
in full lines in FIG. 10, in which the drive casing 78' lies substantially 
flush with the plane of the back panel 64'. The actual length of travel of 
the carriage 74' on the tracks is not critical, but the forward-rearward 
travel must be at least as great as the width of the filmstrip in the 
cassette 10', so that the entire width of the filmstrip can be exposed to 
the light projection opening 71'. 
Four control buttons, 112, 114, 116 and 118, are positioned at the front 
center of the horizontal tray 76' and project forwardly thereof. The 
control buttons are adapted to be manually depressed against a restoring 
spring bias for controlling the speed and direction of spindle rotation. 
The laterally outermost buttons, 112 and 118, preferably control fast 
filmstrip winding in opposite directions, while the inner buttons, 114 and 
116, control slow filmstrip winding in opposite directions. A rheostat 
control interposed in the circuits, controlled by the manual controls, may 
be used to vary the speeds of spindle rotation. 
A generally centrally located, elongated cut-out 120 is located through the 
tray 76'. It is sized and positioned to receive a transparent upper plate 
24' that will cooperate with the transparent plate 22' on the cassette 
10', as described hereinafter. The carriage 74' is shaped to include a 
pair of handles 84' located on opposite sides of the speed controls 112, 
114, 116 and 118, for use in manually moving the carriage 74' forwardly 
and backwardly. And the bottom and sides of the carriage 74' may be 
partially enclosed by thin sheets, such as 111 and 113 to help support the 
weight of the cassette 10'. 
Referring particularly to FIGS. 11-14, the upper plate 24' and its movement 
will now be described. Adjacent each of the longitudinal edges of the 
cut-out 120 are a pair of spaced bores 124 in which upper pivot pins 126 
are horizontally positioned. A link-receiving slot 128 is formed through 
the depth of the tray 74' in association with each horizontally-positioned 
pin 126. Another slot 130 is defined exteriorly of each first slot 128 to 
receive a retaining washer 132 which secures one of the pivot pins 126 in 
position. A flat, elongated link 134 pivots at one end thereof on pin 126 
within slot 128. 
A generally rectangularly-shaped frame 136 is provided with spaced bores 
(not shown) into which lower pivot pins 138 are horizontally positioned. A 
link-receiving slot 140 is formed in the support frame 136 in association 
with each horizontally-positioned pin 138. The other end of each link 134 
is pivotally connected to the lower pivot pin 138 on frame 136, to thereby 
provide parallelogram-type linkages between carriage 74' and frame 136. 
Secured to the plate support frame 136 and extending therebelow, as seen 
in FIGS. 13 and 14, is the transparent glass plate 24' which has a length 
greater than the width of the filmstrip 14'. 
Gravity acting on the weight of the plate support frame 136 and transparent 
plate 24' operates to normally bias and move the frame 136 and plate 24' 
downwardly. The length of the links 134 is such that when the plate 24' is 
in its lowered position engaging filmstrip 14' and pressing it against 
transparent plate 22' of the cassette 10', the links 134 are still 
inclined, as seen in FIG. 4, thereby insuring that the filmstrip 14' is 
pressed with force against plate 22'. Since the top surface of the 
transparent plate 22' on cassette 10' lies in the focal plane of 
projection, the filmstrip 14' is normally maintained in said focal plane 
by the force of gravity acting on plate 24'. 
An elongated, frame-elevating bar 142 extends between each of the 
high-speed control buttons 112 and 118 and the forward transverse edge 144 
of the plate support frame 136. Inward depression of either of said 
high-speed control buttons, 112, or 118, mechanically moves the 
corresponding bar 142 inwardly against plate support frame 136 to move 
frame 136 and transparent plate 24' to swing upwardly about pivot pins 
126. The filmstrip 14' is now released and may move longitudinally between 
the spools 12' of the cassette 10' without frictional drag or resistance 
from the movable plate 24' or from plate 22'. Since no bar extends to the 
low-speed control buttons, 114 and 116, the movable plate 24' remains in 
filmstrip engagement when the low-speed buttons, 114 and 116, are 
depressed to provide relatively low-speed, or inching, longitudinal 
movement of the filmstrip 14, as indicated by the direction arrows in FIG. 
12. 
Viewing FIG. 12, it will be seen that the width dimension of each of the 
upper and lower link-receiving slots, 128 and 140, is substantially 
greater than the width dimension of the links 134 received therein. 
Because of such clearance, the plate support frame 136, and its plate 24', 
are permitted to move laterally and slightly upwardly from the nadir point 
of the virtual pendulum illustrated in FIG. 14 from the full line position 
to the phantom line position. This slight upward movement of plate 24' 
provides sufficient relief to permit inching movement of filmstrip 14' 
without injury to the filmstrip. 
With the high-speed and slow-speed controls described above, it will be 
understood that a high-speed control button, 112 or 118, is first 
depressed to energize a motor means for moving filmstrip 14 at high speed 
along the rows of microimages to approximate location of the micoimage 
frame desired to be viewed. The carriage may then be manually pulled out 
or pushed parallel to the columns of microimages on the filmstrip 14'. 
Then the appropriate low-speed control button, 114 or 116, is activated to 
inch the microphotograph into alignment for illumination and display on 
the viewing screen 66'. 
The Optical System 
The optical system for this second form of the invention is substantially 
identical with the optical system shown in FIG. 9 and described in 
connection with the first embodiment. 
Referring to FIG. 9, the system includes a light bulb 86' from which light 
rays emanate and are directed to the concave mirror 88' which reflects the 
rays to a reflecting mirror 90 and through a condensing lens 92, the 
cassette's transparent plate 22', the filmstrip 14', the carriage's 
transparent plate 24' and into the upper viewing module 52'. 
In the upper module 52', the light rays pass through an objective 
projecting lens 96 and are directed from a first folding mirror 98 to a 
second folding mirror 100 to the viewing screen 66' for display. It is to 
be understood that variations in the size and attitude of the viewing 
screen and the orientation of the mirrors that fold the optical path can 
be made without departing from the scope of the invention. 
Operation 
The operation of the microfilmstrip viewing system of the present invention 
will now be described. The cassette 10' is fitted into place on the 
carriage 24' in the space between the upper viewer module 52' and the 
viewer base 56', such that the drive spindles 80' enter the central bores 
of the cassette spools 12' for driving engagement thereof. The transparent 
cassette plate 22' presents an upper surface above which the filmstrip 14' 
passes. The movable, transparent carriage plate 24' is normally biased to 
clamp filmstrip 14' against the upper surface of plate 22' which defines 
the focal plane for projection of an illuminated image from the 
microfilmstrip. The carriage 74' may be manually translated along the 
tracks provided to select a microimage from the column of frames imprinted 
along the width of the filmstrip 14'. 
When it is desired to move the filmstrip longitudinally along the rows of 
frames imprinted on the filmstrip, one of the fast-speed control buttons, 
112 or 118, is first manually depressed. Depression of one of the fast 
buttons simultaneously causes a bar 142 to pivot the plate support frame 
136 upwardly out of filmstrip contact, and energizes motor means to drive 
the spindle 80' to move the filmstrip 14' longitudinally in the selected 
direction. The fast-speed buttons are used to quickly bring a desired 
filmstrip microimage frame approximately into view. Once the location is 
approximated, depressing one of the slow-speed control buttons, 114 of 
116, operates to energize a motor means to effect inching of the filmstrip 
14' to effect "fine-tuning control", to move the filmstrip 14' to bring 
the desired image into view. The slow-speed filmstrip movement does not 
fully release the filmstrip 14' from engagement by transparent carriage 
plate 24', but play in the linkage permits some small lifting of plate 24' 
which avoids injury to the filmstrip during movement. 
The use of the speed control buttons, 112, 114, 116 and 118, and the 
translatable carriage 74' is thus able to present a selected microimage 
frame from any filmstrip row or column into the path of projected light 
for illumination, enlargement and display on the viewing screen 66'. 
While one form of the invention has been described, it will be understood 
that the invention may be utilized in other forms and environments, so 
that the purpose of the appended claims is to cover all such forms of 
devices not disclosed but which embody the invention disclosed herein.