Microfilm cassette and the projection apparatus for the viewing of same

A cassette is fitted with two cylindrical chambers, each of which has, in its center, a spool axis or shaft. The width of the cassette is slightly greater than the width of a strip of microfilm. The two chambers are joined by a pair of separate, flat plates, which extend the walls of the chambers so that the strip of film runs between the two plates, with a window in the central zone of the two plates. The width of the interval between the two plates is small, to press the film accurately into place at a focal plane of the optical system of a microfilm projector. The apparatus for the use of the cassette makes it possible to cause the film to circulate in both directions.

The present invention relates to a microfilm cassette which may be either 
put into or removed from a reading apparatus without having to rewind the 
film. It also relates to means which make it possible to conduct a search 
through film in, such a cassette. 
Known microfilm cassettes comprise only one magazine. To read the film, it 
is necessary to engage a starting strip on a receiver spool. To remove the 
film, it is first necessary to rewind the entire film into the loader. 
Those maneuvers require a non-negligible time and require the operator to 
handle the film with two hands. 
One object of the present invention is to provide a microfilm cassette 
which avoids those drawbacks, and which is easy and fast to handle. 
According to a characteristic of the invention, a microfulm cassette, which 
is similar to a magnetic tape cassette, has two magazines, each one of 
them having in its center a winding shaft. The width of the cassette is 
slightly greater than the width of the microfilm. The two magazines are 
joined by a pair of separate plates which extend the walls of the 
magazines, so that the film runs between the two plates, the central zone 
of the two plates being transparent. 
According to another characteristic, the width of the interval between the 
two plates is small so that it presses against the film and thus 
accurately positions it in the light trajectory. 
According to another characteristic, the apparatus for using the cassette 
comprises, in addition to the conventional optical devices, a chassis with 
two shafts capable of driving the spools of the cassette's magazines. 
According to another characteristic, the apparatus comprises a cradle 
mounted on glides which make possible its transverse displacement. The 
cradle is fitted to receive the cassette and comprises an opening or a 
transparent zone facing the transparent zone of the cassette, with driving 
means for the transverse displacement of the cradle, the shafts of the 
chassis sliding into the shafts of the spools. 
According to another characteristic, each shaft of the chassis can be 
driven only in its direction of the rewinding of the spool located in the 
corresponding magazine.

The cassette in FIG. 1 is formed of two partial cylinders 1 and 2, closed 
at their non-visible ends, and comprising the slit 3 in one and the slit 
4, in the other cylinder. The edges of the slits 3 and 4 are respectively 
joined by plates 5 and 6. In their centers, as indicated by rectangle 7, 
the plates 5 and 6 are transparent. 
In the centers of the closing plates, not shown, of cylinders 1 and 2, 
there are bearings, not represented, in which are mounted spool shafts 8 
and 9. Shafts 8 and 9 are hollow, with longitudinal keying ribs and 
grooves on the inside, to make it possible to drive them. Film 10 runs 
between plates 5 and 6 and forms on two spools 11 and 12, respectively, 
around shafts 8 and 9. The space between plates 5 and 6 is reduced so that 
the plates serve as film-pressing device, for positioning the film with 
precision in the optical trajectory. 
Of course, the space existing between the two cylinders 1 and 2, and below 
zone 7, must be free from any opaque obstacle, in order to let the light 
go through zone 7 and the film positioned therein. The rear closing 
plates, not represented, are closed by a veil is which closes the edges 
between plates 5 and 6. Such a veil also provided on the front face to 
make the cassette dustproof. 
Inside the cylinders, felts 13 and 14, respectively, are carried by springs 
15 and 16, which, in turn, are respectively mounted, in a suitable manner, 
to ensure the tension of the windings on spools 11 and 12, and to prevent 
an ill-timed unwinding of the film. Another braking and dustproofing 
system for the spools can also be executed using two toric joints per 
spool, mounted, respectively, at the ends of the shafts of the spools, and 
which are in abutment with the front and rear veils. 
On the external surface of each one the cylinders 1 and 2, there is 
provided, in a suitable location, which may be chosen close to the front 
of the cassette as indicated in FIG. 1, a hollow keeper 17 which 
cooperates with a locking ball detent, which will be seen below. 
In the representation of the projection apparatus in FIG. 2, there can be 
recognized a cassette 19 which is identical with the one in FIG. 1. This 
cassette is introduced and maintained in a casing, the opening of which is 
protected by a door 20. The front face of the apparatus comprises, 
further, a button 21 which governs the passing of the film in cassette 19, 
a button 22 which governs the translation of the cassette from the front 
to the rear (and vice-versa) in its casing, a button 23 which regulates 
the lens of the apparatus, a go-stop button 24 which also makes it 
possible to adjust the intensity of light, a `on` signal 25 and a screen 
26. In FIG. 2 there has also been represented in dash lines a halogen lamp 
27, its reflector 28 and a condenser lens 29. 
In the section view in FIG. 3, there is seen again, in the casing lamp 27, 
condenser lens 29, flats or plates 5 and 6 which hold the film 10, as if 
in a sandwich. A first mirror 31 sends back the light beam received from 
lamp 27 passing through film 10 toward a second mirror 32, which sends the 
light back to the rear face of screen 26. Buttons 23, 22 and signal 25 
also are indicated in FIG. 2. The section view in FIG. 3 makes it possible 
to illustrate the optical functioning of the apparatus, which is entirely 
conventional. 
In FIG. 4, there has been represented in perspective a cradle for receiving 
cassette 19. It is essentially formed of a rigid sheet 33 comprising an 
upper flat face 34, with a window 35 corresponding to zone 7 of the 
cassette, the flat face being extended to the right and to the left by two 
half-cylinders 36 and 37. The common diameter of these half-cylinders 
corresponds to the common external diameter of cylinders 1 and 2. Each 
half-cylinder 36 or 37 carries on the outside, along its horizontal 
generatrix, a slider, 38 or 39 respectively. In addition, slider 38 has at 
its two ends, projecting toward the outside, two small blocks 40 and 41 
which comprise threaded holes which are aligned and which define the axis 
of an endless feed screw 42, FIG. 6., driven by an operation of button 22. 
The rear ends of the half-cylinders 36 and 37 form veils presenting 
openings for shafts 43 and 44 which drive the shafts of spools 8 and 9. 
Finally, the cradle comprises, in front of sliders 38 and 39, lodgings for 
conventional locking ball detents 45 and 46, which may assume an unlocked 
position toward the outside and a locked position toward the inside. 
Locking systems others than the detent which has just been described could 
also be used. 
In FIG. 5, there has been represented cradle 47 seen from the front, and 
mounted in the casing of the projection apparatus. That casing is limited 
by two lateral faces 48 and 49, but especially it comprises two vertical 
partitions, each of which has a horizontal groove 52 or 53. Inside the 
grooves, there are respectively sliders 38, 39. 
The view from the top in FIG. 6 shows the other parts of the casing 
according to FIG. 5, that is to say back 54 and a vertical wall 55 are, 
perpendicular to walls 50 and 51, and are placed slightly forward of back 
54, and a front face 56 into which there is cut out an opening for making 
it possible to introduce the cassette, the opening being normally closed 
by the door 20 in FIG. 2. Feed screw 42 is mounted at the end of which 
button 22, and is carried by bearings from back 54, and the front face 56. 
As screw 42 runs through the threaded holes of blocks 40 and 41, it is 
possible to displace in translation, by operating button 22, cradle 47 
sliding in grooves 52 and 53. A shaft 57 is mounted at the end of which 
button 21, and is carried by bearings of back 54 and of the front face 56. 
Shaft 57 is fixed in solidary with a gear 58 close to back 54. Shaft 44 is 
carried or supported by bearings on back 54, and on wall 55. There are two 
gears 59 and 60 placed in front of each other between walls 54 and 55. 
Gear 59 comprises a circular groove on which there is mounted a belt 61 
which runs over a pulley 62 mounted on the shaft 43 between walls 55 and 
54. Shaft 43 is carried or supported by bearings on walls 54 and 55. 
It appears in FIG. 6 that the depth of cradle 47 is in the order of one 
half of the depth of the volume defined by partitions or walls 50, 51 and 
55. In that volume, the shafts 43 and 44 form pins on which fit the hollow 
shafts 8 and 9 of the cassette mounted in cradle 47. Shafts 43 and 44 of 
course have ribs and grooves, to drive shafts 8 and 9 into rotation. 
Shaft 57 now can rotate when button 21 is depressed, but it can be pushed 
in as shown in FIG. 6, a position in which its gear 58 engages gear 60 
which is fixed on shaft 44, or it can be pulled toward the front, as shown 
in FIG. 7, a position in which its gear 58 engages gear 59 which is 
mounted, free to rotate, on shaft 44. 
In the pushed down position, when button 21 is rotated in the 
counterclockwise, the film is wound around spool 9, driven by shaft 44. In 
the pulled out position, it is possible, by rotating button 21 in the 
opposite or clockwise direction, to rewind the film around spool 8, driven 
by shaft 43, pulley 62, belt 61 and gear 59. A wrong maneuver is easily 
detected because the film does not move. 
It thus appears that by maneuvering button 21 it is possible to cause the 
film to run under area 63, from the right to the left, or from the left to 
the right. In addition, by maneuvering button 22, there is a translation 
of cradle 47 which carries the cassette that is to say the film, is 
displaced from the front to the rear or vice-versa under area 63. Area 63 
is located on the optical axis of the apparatus. Thus buttons 21 and 22 
make it possible to center the image on screen 10. 
FIG. 8 is a section view taken along the line VIII--VIII in FIG. 6, in 
which there are found again button 22, shaft 42, the blocks 40 and 41, and 
partition 50. 
With reference again to FIG. 6, it appears that the internal front parts of 
walls 50 and 51 are made thinner in areas 64 and 65, to make it possible 
for locking devices 45 and 46 to disappear. 
In order to use the projection apparatus with film cassettes, according to 
the present invention, the empty cradle, by means of button 22, is 
displaced forward. It is assumed that grooves 52 and 53 (FIG. 5) are 
closed toward the front in order to form an abutment. When the cradle has 
come against the abutment, the locking devices 45 and 46 move into spaces 
64, 65 and are unlocked, this making it possible to introduce the cassette 
into the cradle. The cradle is pushed in completely. Afterwards, as soon 
as the cradle which contains the cassette moves back, the locking system 
45, 46 move out of spaces 64, 65 and immobilizes the cassette in the 
cradle. 
As a function of the picture projected, the operator either unwinds or 
winds the film. It is possible to provide, for example, on the edge of the 
film for a footage marking. Once the desired image zone has been found, 
the image is centered by means of buttons 21 and 22; then, button 23 may 
be used to permit a change of lens and ensure the correct magnifying power 
of the image which has to be consulted. 
It must further be understood that the cassette and the apparatus make it 
possible to view the microfilm either over its entire width and over a 
length which is the equivalent of the transparent window 7 of the 
cassette, or over a reduced part, by using lenses with different 
magnifying powers, associated with adjustable diaphragms or a slide with 
holes lodged above the condenser. 
It is also possible to provide for a motorization of the reading table, the 
buttons of the manual mechanical control being replaced by pushbuttons 
governing micro-motors mounted, especially at the ends of shafts 42 and 
57. 
In addition, it is possible to provide, on the edge of the film, for a 
magnetic footage marking which, associated with a suitable reading head, 
makes it possible to perform an automatic search. 
On the transparent parts of plate 5, horizontally indexed marking lines may 
be engraved, traced or drawn, so that it is possible to locate, during 
projection, the lateral zone which are sought. 
The apparatus can, for example, serve as map reader in a vehicle, the maps 
to be consulted being recorded on the film.