U.S. patent number 3,737,941 [Application Number 04/838,760] was granted by the patent office on 1973-06-12 for apparatus for cleaning film.
This patent grant is currently assigned to Jerome B. Gracey, Dominic J. Squatrito. Invention is credited to Arthur J. Miller, Raymond Perkins, Harold E. Sullivan.
United States Patent |
3,737,941 |
Miller , et al. |
June 12, 1973 |
APPARATUS FOR CLEANING FILM
Abstract
An ultrasonic film cleaner has an enclosed shell within which is
provided an internal solvent recovery system for recapturing
solvent stripped from the ultrasonically cleaned film. The
recovered solvent is recirculated to fluid nozzles which add
solvent to a cleaning tank to skim dirty solvent over a spillway
into an offset boiling tank, where contaminates precipitated to
avoid build up of contamination in the solvent bath. An air
filtration and recirculation system is provided to maintain a dust
free environment within the shell. The film transport mechanism
preferably has rolls with snap-on mountings for ease in adapting
the cleaner for various width films.
Inventors: |
Miller; Arthur J. (Fort Lee,
NJ), Perkins; Raymond (Plainville, CT), Sullivan; Harold
E. (East Hampton, CT) |
Assignee: |
Gracey; Jerome B. (Hartford,
CT)
Squatrito; Dominic J. (Manchester, CT)
|
Family
ID: |
25277980 |
Appl.
No.: |
04/838,760 |
Filed: |
July 3, 1969 |
Current U.S.
Class: |
15/100; 134/9;
15/302; 134/64R |
Current CPC
Class: |
G03D
15/00 (20130101) |
Current International
Class: |
G03D
15/00 (20060101); B08b 007/02 () |
Field of
Search: |
;134/1,9,15,64,122,90,107,108 ;15/302,306,307,100,4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Moore; Richard E.
Claims
We claim:
1. An apparatus for ultrasonically cleaning strip material
comprising, in combination:
an enclosed shell defining a cleaning compartment;
an ultrasonic cleaning unit including a cleaning chamber containing
an ultrasonically agitated solvent bath mounted within said
shell;
means for continuously removing contaminants from said solvent
bath;
a nozzle positioned above said solvent bath to add make-up solvent
to said solvent bath;
a drying chamber mounted within said shell;
means for mounting feed and take-up reels within said shell;
a strip transport mechanism for sequentially passing a strip of
material from said feed reel through said solvent bath for cleaning
and through said drying chamber for stripping to said take-up
reel;
means for forcing a flow of filtered air heated to a temperature
greater than the boiling point of said solvent through said drying
chamber to evaporatively strip solvent from said strip;
a solvent recovery chamber mounted within said shell having an
inlet adapted to receive said drying air from said drying chamber
and an outlet;
refrigerating means disposed within said solvent recovery chamber
between said inlet and said outlet to condense and separate said
evaporated solvent from said drying air;
means for recirculating said separated solvent back to said nozzle;
and
means for continuously forcing a flow of filtered air over said
feed and take-up reels.
2. The apparatus of claim 1 in which said means for forcing a flow
of heated filtered air through said drying chamber and means for
forcing a flow of filtered air over said feed reel and take-up reel
comprise:
an air blower mounted within said shell to circulate air
therethrough;
a filter;
conduit means for directing air from the pressure side of said
blower to said filter;
a heating chamber opening into said drying chamber;
means for directing a portion of said filtered air to said heating
chamber;
means for directing the remainder of said filtered air over said
take-up and feed reels;
a return duct interconnecting the outlet of said solvent recovering
chamber with the suction side of said blower to recirculate said
drying air; and
a return duct adapted to direct the air flowing over said reels to
the suction side of said blower for recirculation, whereby a
substantially dust-free environment is maintained within said shell
by an internally contained air recirculation system.
3. The apparatus set forth in claim 1 in which said means for
removing contaminants from said solvent bath comprises:
an offset boiling tank; and
one wall of said cleaning chamber having an aperture therein which
is in fluid communication with said boiling tank, the lower edge of
said aperture defining a spillway for said solvent bath to allow
contaminated solvent to continuously spill over into said boiling
tank as clean solvent is added to said solvent bath, whereby
contaminants may be continuously precipitated from said solvent as
the solvent is vaporized in said boiling tank.
4. The apparatus of claim 3 in which said ultrasonic cleaning unit
further includes:
a chilling chamber positioned above said cleaning chamber;
refrigerating means secured within said chilling chamber to
condense vapor emitted by said boiling tank;
a solvent collecting trough positioned within said chilling chamber
below said refrigerating means to collect condensed solvent;
a reservoir secured to the exterior of said cleaning tank; and
a conduit interconnecting said collecting trough and said
reservoir.
5. The apparatus of claim 4 in which said solvent recovery chamber
is secured to the exterior of at least one wall of said chilling
chamber, said separated solvent recirculating means comprising:
a conduit interconnecting said solvent recovery chamber and said
reservoir;
a conduit interconnecting said reservoir and said boiling tank;
a pump;
a conduit interconnecting said reservoir and the suction side of
said pump; and
a conduit interconnecting the pressure side of said pump with said
nozzle.
6. The apparatus of claim 5 wherein said drying chamber is
positioned above said cleaning chamber which further includes
mechanical stripping means mounted in said drying chamber for
mechanically stripping liquid solvent from said film, said
mechanically stripped solvent falling back into said ultrasonic
cleaning unit for recirculation.
7. The apparatus of claim 1 in which said strip transport mechanism
includes a plurality of rolls, each said roll having a detachable
roll mounting assembly comprising:
a ball resiliently secured to the central bore of said roll
assembly, said ball extending into said bore in its rest
position;
a shaft having a cross-section complementary to said bore, said
shaft having a longitudinal ball guiding groove formed therein
extending from its terminal end inward to a recessed nest having a
configuration complementary to said ball, whereby said roll may be
mounted on said shaft by relative movement between said shaft and
roll wherein said ball is guided axially along said ball guiding
groove until it is resiliently urged into said nest.
8. In an apparatus for cleaning strip material having a cleaning
chamber containing an ultrasonically agitated solvent bath, an
evaporative drying chamber, and means for sequentially passing the
strip therethrough, means for forcing a flow of filtered air heated
to a temperature greater than the boiling point of said solvent
through said drying chamber, means for continuously removing
contaminants from said solvent bath which comprises: an offset
boiling tank; one wall of said cleaning chamber having an aperture
which is in fluid communication with said boiling tank, the lower
edge of said aperture defining a spillway for said solvent bath to
allow contaminated solvent rinsed from the film to continuously
spill over into said boiling tank as solvent is added to said
solvent bath, whereby said contaminants may be continuously
precipitated from said solvent as the solvent is vaporized in said
boiling tank.
9. In an apparatus for cleaning strip material having a cleaning
chamber containing an ultrasonically agitated solvent bath, an
evaporative drying chamber for stripping solvent from the strip,
and means for sequentially passing the strip therethrough, a
chilling chamber positioned between the cleaning chamber and drying
chamber having refrigerating means for condensing solvent vapor in
said chamber.
10. The apparatus of claim 9 in which said apparatus further
includes a solvent boiling tank, and means providing a passageway
for permitting solvent from the cleaning chamber to flow to the
boiling tank and permitting vaporized solvent from the boiling tank
to flow into the chilling chamber.
11. The apparatus of claim 9 in which said refrigerating means is
disposed along the interior surface of the chilling chamber and a
trough extends along the bottom end of the chilling chamber for
collecting condensed solvent.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to the cleaning of photographic
films and the like and is more particularly directed to an improved
apparatus for ultrasonically cleaning strips of motion picture
film, magnetic and video tapes and similar strip materials.
The well known tendency of the inherently soft surfaces of a
photographic film to pick up dust particles, grease, and other
foreign matter presents a continuous problem in the preparation of
motion picture films wherein the single original film must be
copied to produce several hundred exhibition copies of the film.
During the copying process, several direct copies are made from the
original film and the exhibition copies are normally made by
copying the direct copies. Any foreign matter on the film being
copied is magnified during the copying procedure to produce
undesirable blurred areas or spots on the copy negative.
Moreover, as a film is unwound and rewound, it becomes electrically
charged and will pick up dust and dirt from the atmosphere. As the
film is rewound, the winding tensions will cause the collected dirt
trapped between adjacent windings of the reel to scratch the soft
film surfaces, particularly the image carrying emulsion coated
surface. Such scratches also result in imperfections on the copy
produced. It is, therefore, necessary to clean a film periodically
during the copying process to insure that marketable exhibit copies
are produced to protect the high investment represented by the
original.
In the devices heretofore known using an ultrasonically agitated
solvent to clean films, two sources of impurities hinder cleaning
efficiency. The first source of impurities are those removed from
the film which remain in the solvent to progressively contaminate
the solvent bath. The second source of impurities is the atmosphere
from which the film accumulates dust after it leaves the ultrasonic
cleaning chamber and as it is rewound on the take-up reel.
Another undesirable feature of prior art film cleaners is that
expensive external ducts and solvent recovery apparatus are
frequently required to recover the cleaning solvent stripped from
the film. The economic feasibility of employing external solvent
recovery apparatus depends, of course, on the volume of solvent
evaporated and the cost of the recovery equipment. In practice, it
has been found that only those installations using several film
cleaners are able to recoup the cost of external recovery apparatus
in recovered solvent, while installations having a lesser volume of
use incur an increased operating expense in the form of lost
solvent. It is, therefore, highly desirable to provide a film
cleaner with an internal solvent recovery apparatus without greatly
increasing the cost of the machine.
An additional undesirable feature of previous film cleaners is that
the film transport mechanisms therein cannot be readily adapted for
accommodating different width films.
SUMMARY OF THE INVENTION
In accordance with Applicant's invention, a film cleaner is
provided with an enclosed shell. Within the shell are mounted an
ultrasonic cleaning unit, evaporative and preferably mechanical
stripping means, an air filtering and recirculating system and a
solvent recovery system. The film is guided by a film transport
merchanism sequentially from a feed reel, through an ultrasonic
cleaning tank where it is cleaned, preferably past spray nozzles
where a spray of clean solvent rinses dirty solvent from the film,
through the drying chamber where solvent is stripped from the film
preferably by stripping rolls, after which it is evaporatively
dried by a flow of filtered heated air and then wound on a take-up
reel.
Substantially all of the stripped solvent is returned to the
cleaning tank through an internal solvent recovery system to
significantly reduce the operating expense of the device by
minimizing the amount of make-up solvent required.
The cleaning tank is provided with means for continually skimming
contaminated solvent from the cleaning tank into a boiling tank
wherein the contaminants may be precipitated as the solvent
vaporizes to avoid progressive contamination of the solvent bath,
whereby cleaning efficiency is enhanced.
Moreover, filtered air is recirculated throughout the enclosed
shell and through the drying chamber to insure a dust-free
environment that also increases cleaning efficiency.
A further feature of this invention is the provision of a snap-on
mounting means for the rolls of the film transport mechanism to
allow facile interchangability of various sized rolls so that the
cleaner may be rapidly adapted for cleaning different width
films.
It is accordingly an object of this invention to provide an
ultrasonic strip material cleaner having an internal solvent
recovery system capable of recovering substantially all solvent
stripped from the processed material.
Another object of the invention is to provide an ultrasonic film
cleaner in which cleaning is performed in a decontaminated
environment.
It is a further object of the invention to provide an ultrasonic
film cleaner in which contaminants are continuously removed from
the solvent bath.
A still further object of the invention is to provide a strip
material transport mechanism with rolls having snap-on mountings
for rapid and easy mounting and dismounting of the rolls.
These objects and other objects, features and advantages of the
present invention will become apparent as the description proceeds
with reference to the drawings wherein:
FIG. 1 is a front elevation of the preferred embodiment of an
apparatus according to the invention;
FIG. 2 is a side elevation of the apparatus shown in FIG. 1 with
the right wall of the shell broken away;
FIG. 3 is a perspective view of the ultrasonic cleaning unit
employed in the preferred embodiment;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 3;
FIG. 5 is a sectional view taken along line 5--5 of FIG. 3;
FIG. 6 is an exploded side elevation illustrating the snap-on
mounting provided for the rolls of the film transport;
FIG. 7 is a side elevation of a roll for wider film which has the
same snap-on mounting as that shown in FIG. 5; and
FIG. 8 is a section of the safety roll assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The description of the preferred embodiment of the invention will
now proceed with continued reference to the drawings wherein like
reference numerals are used to identify the same elements in the
various views. It should be understood that the invention may be
used to clean strip materials other than motion picture film as
described, such as magnetic and video tapes and the like.
Referring initially to FIGS. 1 and 2, a cleaner 10 has a
rectangular shell 12 which surrounds the sides of the apparatus. A
vertical mounting panel 14 secured within the shell 12 intermediate
its front and rear edges divides the cleaner into two general
compartments, a forward enclosed cleaning compartment 16, wherein
the cleaning elements hereinafter discussed are mounted, and a rear
compartment 18 wherein the electrical and mechanical accessories
needed to actuate the film transport are mounted. The cleaning
compartment 16 is sealed to the ambient atmosphere by glass doors
20 mounted on the forward edge of the shell 12 upon hinges 22 and a
forward cover plate 23 which is broken away to expose the elements
mounted in the lower portion of the cleaning compartment.
Positioned within one side of the cleaning compartment 16 are a
feed reel 24 for dirty film 26 mounted on a feed reel shaft 28
secured to the mounting panel 14 and a take-up reel 30 mounted on a
driven take-up shaft 32, the latter shaft also being secured to the
mounting panel 14.
Briefly following the travel of the film through the cleaning
compartment 16, the film 26 passes from the feed reel 24 over a
guide roll 34 downward into an ultrasonic cleaning chamber 36
provided in the bottom portion of an ultrasonic cleaning unit 38.
The ultrasonic cleaning chamber 36 contains an appropriate liquid
solvent bath 40 which is ultrasonically agitated in a conventional
manner by transducers 42 and 44 to effectively clean the film 26 as
the film passes horizontally through the cleaning chamber 36 over
frame guide rolls 46 and 48.
On exiting from the solvent bath 40, the emulsion and base sides of
the film 26 are preferably rinsed by a flow of clean solvent
emanating from a pair of spray nozzles 50 and 52. The rinsed film
is then passed upward through a chilling chamber 54 to a drying
chamber 56 where the liquid solvent superficially adhering to the
film is stripped. Two stripping means are shown. The first means is
a pair of soft fiber-surfaced stripping rolls 58 and 60 rotatably
mounted within the drying chamber, which rolls are accurately
spaced on each side of the film 26 so as to lightly contact the
film. The stripping rolls 58 and 60 are preferably Dacron fiber
plush rollers of the type developed by Eastman Kodak Company. By
rapidly rotating the stripping rolls against the flow of the film
26 in the direction indicated, say at 3,000 rpm, some of the liquid
solvent is mechanically brushed from the film without causing
damage thereto. The remainder of the liquid solvent is
evaporatively stripped by a downward flow of heated, dust-free air.
To avoid film damage the film 26 should be completely dry before it
passes over a first drying chamber roll 62 mounted within the
drying chamber 56. Such stripping may be accomplished solely
evaporatively without the stripping rolls 58 and 60 by lengthening
the distance between the nozzles 50 and 52 and the first drying
chamber roll 62, increasing the temperature and flow rate of the
drying air and/or by decreasing the film feed rate. We prefer to
mechanically strip a portion of the adhering solvent with the
stripping rolls 58 and 60 to avoid increasing either the length of
the drying chamber 56 or the heat transfer requirements necessary
to recover evaporated solvent for processing film at high
speed.
The dried film then passes over the roll 62 downward under a second
drying chamber roll 64 and then upward out of the drying chamber 56
over a film drive roll 66 under a safety roll 68 and then under a
conventional tension control arm 70 to the take-up reel 30. The
mounting of the reels 24 and 30 and the rolls 34, 46, 48, 62, 64,
66 and 68 (hereinafter collectively referred to as the film
transport mechanism) will be described in greater detail below. A
U-shaped shield 71 is provided under the second drying chamber roll
60 to shield the dry film from any solvent splashing up from the
stripping rolls.
The structure of the ultrasonic cleaning unit 38 is best seen in
FIGS. 3, 4 and 5 and generally comprises the lower cleaning chamber
36 and the larger chilling chamber 54 positioned above and
symmetrically about the cleaning chamber 36. The upper edges 72 of
the cleaning chamber walls 74 extend into the lower portion of the
chilling chamber 54 and the lower portion of the chilling chamber
walls 76 have inward turning depending flanges 78 which are secured
to the cleaning chamber walls 76 to form a solvent collecting
trough 80. An upper and lower set of chilling chamber cooling coils
82 and 84 respectively, are secured to the inner sides of the
chilling chamber walls 76 directly above the solvent collecting
trough 80.
A solvent recovery chamber 86 is disposed externally around and
secured to two sides of the chilling chamber 54. The solvent
recovery chamber 86 receives the drying air passing through the
drying chamber 56 through an inlet port 88 and passes the drying
air through a series of baffles 90 over cooling fins 92 to an
outlet port 94. A deflector plate 96 (see FIG. 1) is provided to
deflect most of the vaporous solvent laden drying air and the
liquid solvent brushed from the film 26 into the inlet port 88. The
vaporous solvent evaporated from the film 26 in its passage through
the drying chamber 56 is condensed from the drying air by the
cooling fins 92 and falls to the bottom of the solvent recovery
chamber together with the brushed off liquid solvent. The
solvent-free drying air exiting through the outlet port 94 is
recirculated through the apparatus in the manner hereinafter
described. The recovered solvent passes through a drain conduit 98
interconnecting the bottom of the solvent recovery chamber 86 with
a solvent reservoir 100 secured to the exterior of the cleaning
chamber 36, which reservoir also contains cooling coils 102.
An offset boiling tank 104 provided with conventional heaters 106
is positioned adjacent the cleaning chamber 36 and is in fluid
communication therewith through an aperture 108 feeding into the
upper portion of the cleaning chamber. Solvent vapor enters the
cleaning compartment through the aperture 108 and forms a vapor
blanket above the surface of the solvent bath 40 in the chilling
chamber 54. The height of the vapor blanket is controlled by the
cooling coils 82 and 84 which condense the vapor and cause it to
drop into the solvent collecting trough 80, from whence it passes
to the solvent reservoir 100 through a drain conduit 110 (FIG. 5).
The temperature of the chilling chamber cooling coils should
preferably maintain the vapor blanket at a height intermediate the
cooling coils 82 and 84 so that no solvent leaks into the remainder
of the cleaning chamber. The cooling coils 82 and 84 also condense
vaporous solvent from any drying air not deflected into the inlet
port 88 of the solvent recovery chamber 86, while stray brushed-off
solvent falls either into the solvent bath 40 or the collecting
trough 80.
There are thus two sources of solvent for the reservoir 100, the
solvent recovered in the recovery chamber 86 and solvent vaporously
emanating from the boiling tank 104 which is condensed in the
chilling chamber 54 and collected in the collecting trough 80. A
portion of the condensed solvent is circulated from the reservoir
to the cleaning tank through flexible piping 112 to the suction
side of a pump P and hence from the pressure side of the pump P to
the spray nozzles 50 and 52, via piping 114, which nozzles serve
the primary function of adding make-up solvent to the solvent bath
40 while also rinsing the film. The remainder of the condensed
solvent passes to the boiling tank 104 through conduit 116 for
recirculation as described above. The apparatus, therefore,
incorporates an internal solvent recovery system that recovers in
excess of 90 percent of the solvent stripped from the film.
Any water present in the solvent or drying air floats to the top of
the solvent in the reservoir and passes out the U-shaped water
drain 118. The solvent level in the boiling tank 104 is maintained
at a predetermined height by a conventional pressure gage 107
provided on the bottom of the tank 104, which gage deenergizes the
heaters 106 when the solvent level is too low to avoid boiling the
boiling tank dry.
As shown in FIG. 4, the level of the solvent bath 40 in the
cleaning chamber 36 is regulated by the lower lip 120 of the
aperture 108 which functions as a spillway. The contaminants
removed from the film 26 remain on the top of the bath 40 in either
dissolved or undissolved form and continuously spill over into the
boiling tank as solvent is added by the nozzles 50 and 52. As the
solvent is vaporized the impurities precipitate to the bottom of
the boiling tank 104, from whence they may be periodically removed
through a removable clean-out door 122. Thus impurities are
continuously removed from the recycled solvent. If desired, a
filter may be placed in conduits 112 and 114 to further insure that
the solvent in the cleaning chamber 36 is clean.
The chilling chamber cooling coils 82 and 84, solvent recovery
chamber cooling fins 92 and reservoir cooling coils 102 are
sequentially supplied in a conventional manner with an appropriate
refrigerant through conduits 124 to preferably maintain the upper
cooling coils 82 at 35.degree. -40.degree. F so as to achieve
maximum condensation while avoiding frosting, with the remaining
cooling elements maintained at temperatures lower than the boiling
point of the solvent.
With reference once again to FIGS. 1 and 2, ultrasonic energy is
supplied the transducers 42 and 44 from a conventional ultrasonic
generator 126 in a conventional manner.
The upper immersible transducer 42 and the frame rolls 46 and 48
are mounted on a frame 128, which frame has appropriate bearings
that slidably engage vertical slide rods 130 and 132 secured to the
mounting panel 14. The frame 128 also has a vertical toothed rack
134 which meshes with a pinion 136 mounted on the drive shaft of a
slide motor 138, the latter being mounted on an appropriate bracket
140 in the rear compartment 18. The travel of the frame 128 on the
slide rods 130 and 132 is accurately controlled by microswitches
142 and 144 which are connected to the slide motor 138 through
appropriate circuitry to deenergize the slide motor when tripped by
the frame. The lower microswitch 144 should be positioned so that
when the frame 128 is lowered into the ultrasonic cleaning unit 30
during cleaning (FIG. 1), the frame rolls 46 and 48 guide the film
horizontally between the transducers at the optimum distance for
cleaning. The upper microswitch 142 should, of course, be
positioned so that the frame 128 may be raised sufficiently to
allow easy access to the frame rolls for threading. The drying
chamber 56 also has a hinged door 146 to give access to the
stripping rolls 58 and 60 and the drying chamber rolls 62 and 64
for threading.
The description will now proceed to the air circulation and
filtration system provided to recirculate dust-free air throughout
the cleaning compartment. A blower 148 located in the bottom of the
cleaning compartment 16 forces air through an air supply duct 150
which runs along the bottom and up one side of the cabinet to feed
into an enclosed plenum 152 at the top of the cleaning chamber.
From the plenum 152 the air passes through absolute filters 154
which filter it to 0.5 microns with a greater than 99 percent
efficiency to render it substantially dust-free. The filtered air
is then divided into two streams. One stream, indicated by arrows
156, passes through a perforated covering plate 158, downwardly
over the take-up and feed reels 30 and 24 to insure that the film
26 is processed in a decontaminated atmosphere. The air flow 156
passes back to the suction side of the blower 148 through return
duct 160 for recirculation.
Another stream of air as indicated by arrows 162 passes through the
filters 154 into a heating chamber 164 through a cut out portion
159 of the perforated plate 158 where it is heated by conventional
heater 166 to a predetermined drying temperature. The heated air
then passes to the drying chamber 56 in a flow counter to the
direction of film travel to evaporatively strip solvent from the
film. The solvent laden drying air then enters the solvent recovery
chamber 86 through the inlet port 88, and, after solvent has been
condensed therefrom, the drying air flow 162 passes from the outlet
port 94 to the blower 148 via a drying air return duct 168 for
recirculation through the cleaner.
In practice, we have found it desirable to deliver approximately
175 cfm of air from the blower 148 to the plenum 152 at 1/2 inch
static pressure. The drying air flow 162 is preferably about 100
cfm and the reel air flow 148 should be about 75 cfm. Regulation of
the division of air flowing from the plenum can, of course, be
accomplished by appropriate design of the perforated cover plate
158 and cut out portion 159 thereof.
The drying air flow 162 should be heated by the heater 166 to a
temperature greater than the boiling point of the solvent used but
should not be so great as to cause the film to curl or otherwise
become distorted. We have found that for use with the preferred
type of solvent described below, an air temperature in the range of
130.degree. to 140.degree. F is satisfactory.
The preferred type of solvent for use in the cleaner is one with a
relatively low boiling point to facilitate recovery in the solvent
recovery chamber 86, one which does not attack either the materials
from which the cleaner is constructed or the strip material being
cleaned, and yet one which will effectively clean the strip
material when subjected to ultrasonic energy. An example of such a
solvent is an azeotropic mixture of 88 percent
trichlorotrifluoroethane and 12 percent ethanol which boils at
about 115.degree. F, is an effective cleaning solvent and does not
attach standard construction materials such as stainless steel,
aluminum, brass and nylon. The high specific gravity of this
solvent also effectuates skimming of contaminants from the solvent
bath 40 into the boiling tank 96 and separation of water from the
solvent in the reservoir 100 because water and contaminants float
in the solvent. It should be appreciated that the above-mentioned
solvent is only an example of a solvent capable of satisfactory use
with the invention, and other solvents having similar properties
may be used as well.
With reference now to FIG. 2, the film is driven through the
cleaner 10 by the drive roll 66 which is mounted on the drive shaft
170 of a film motor 172. The film motor 172 is secured in the rear
compartment 18 to the mounting panel 14 upon an appropriate bracket
174 with its drive shaft 170 passing through the mounting panel
14.
To insure a uniform tension in the film an electrical pot 176 is
secured to the feed reel shaft 28 to produce a minimum drag so that
the feed reel 24 does not coast as its speed of rotation
accelerates due to the constant rate of film removed while the
diameter of reeled film decreases. On the other hand, the take-up
reel 30 must rotate at progressively decreasing velocity to
accommodate a constant take-up film while the diameter of the
reeled film increases. To this end, the take-up reel shaft 32 is
driven by a take-up motor 178 mounted in the rear compartment 18 on
bracket 180 through an electrical clutch 182 and brake 184. An
electrical pot 186, also positioned on the shaft 32, actuates the
brakes 184 and clutch 182 to insure that the torque on the take-up
reel shaft 32 is constant by causing the electrical clutch 174 to
slip more and more at the reeled film diameter increases.
The stripping rolls 58 and 60 are mounted on rotatable shaft which
shafts pass through the mounting panel 14 where a pair of meshed
pinion gears are mounted thereon. One of the shafts is driven
directly by a stripping roll motor mounted to the rear of the
mounting panel 14 upon an appropriate bracket, with the
intermeshing of the gear pair providing the requisite
counter-rotation for the other shaft. The driving means for the
stripping rolls is well known to those skilled in the art and it is
therefore believed that further illustration is not necessary.
The safety roll 68 is mounted on a non-rotating shaft 188 which is
pivoted within a housing 190 secured to the mounting panel 14. An
actuating rod 192 is slidably mounted through the panel 14 and is
secured to the shaft 188 in a conventional manner to reciprocate
horizontally in response to pivoting of the shaft 188 so that when
the film 26 passing under the roll 68 is tensioned, the shaft 188
is horizontal and the rod 192 depresses a microswitch 194. The
energizing circuitry for the drive motor 172, the take-up motor 178
and the stripping rolls motor is coupled through the microswitch
194, which motors will operate only when the switch 194 is
depressed. If the film 26 breaks during cleaning, the upward
pressure on the safety roll 68 will be released to cause the shaft
188 to pivot, whereby the microswitch 194 will be released to
deenergize the film transport.
A feature of the present invention is that provision is made for
easily changing the elements of the film transport for use with
various width films. With reference now to FIG. 6 wherein the
assembly for mounting the idler roll 34 is shown in an exploded
view, the idler roll 34 is preferably fabricated of Nylon and has a
central bore 196 and collar 198 adapted to receive a complementary
bushing 200, preferably of aluminum or stainless steel. The roll 34
and bushing 200 may be assembled by passing a set screw or the like
through the radial holes 202 and 204, respectively. The bushing 200
has a central bore 206 adapted to fit on a complementary idler 208
and also has a spring loaded ball 210 extending partially into the
bore 190 in its rest position. A longitudinal ball guiding groove
212 is formed on the surface of the idler shaft 208 and extends
longitudinally from the shaft terminal end 214 to a recessed nest
216 having an appropriate configuration to receive the
spring-loaded ball 210, whereby the roller and bushing assembly may
be securely mounted on the shaft 208 by merely inserting the
bushing and roller assembly onto the shaft with the ball 210
passing along the guide groove 212 until the ball snaps into the
nest 216. This mounting process may be reversed to dismount the
roll 34 for replacement with a different width roll.
It should be apparent that rolls 34 of various widths may be
provided with similar snap-on fittings so that the film transport
may be easily converted for processing various width films by
merely changing the roll size used. For example, the roll 34 shown
in FIG. 6 is for 16mm film while roll 34' shown in FIG. 7 is for
35mm film, which rolls can both be mounted on the same shaft 208
with the same bushing 184. If it is desired to clean wider material
such as 3 inch wide video tapes, the shaft 208 and bushing 200 may
be elongated accordingly. The width of the stripping rolls 58 and
60 should preferably equal the width of the widest material to be
processed by the cleaner 10, for example 3 inches for television
video tape.
The shaft 208 is rotatably mounted within a shaft housing 218 on
appropriate sealed bearings 220, the housing 218 being secured to
the mounting panel 14 as by screws passing through a raised
mounting flange 222.
The mounting of the idler roll 34 is shown for illustrative
purposes, and it should be understood that the other elements of
the film transport (with the exception of the safety roll 68) are
similarly mounted on rotatable shafts, either on the mounting panel
14 or the frame 128, as the case may be. Since the safety roll
shaft 188 does not rotate axially, bushing 224 of the safety roll
68 (see FIG. 8) has bearings 226 in its outer surface to allow the
roll 68 to rotate about the bushing 224, while the bushing 224 may
be mounted on the shaft 188 by the interaction of ball 210 and nest
216 in the same fashion as the other film transport elements. A
snap ring 228 prevents axial movement between the safety roll 68
and the bushing 224.
It should be understood that the present disclosure is solely for
the purpose of illustration and that this invention includes all
modifications and equivalents falling within the scope of the
appended claims.
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