Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS AND METHOD FOR DOCTOR BLADE ` -,
REPLACEMENT IN A FLEXOGR~PHIC PRESS ~-
~ACKGROUND AND SUMMARY OF INVENTION~
This invention relates to an apparatus and method for
doctor blade replacement in a flexographic press and, more
particularly, to a fountain embodying a movable holder for the
blades. --~
Conventionally, doctor blades are provided to define
the upper and lower ends of a fountain associated with an~ink,
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transfer roll -- such as an anilox roll. Illustrative of the
basic structure is that shown in co-owned Patent S,125,341.
When it is desired to replace the doctor blades, a
labor-intensive situation arises. Bolts have to be loosened and
then retightened in order to clamp the doctor blades and if the
operation is not carefully handled, a wave will be introduced
into the blade. This is avoided by the instant invention which
provides a doctor blade holder which is movably mounted on a
sub-frame of the press. The sub-frame of the press is part of
the basic fountain structure and is located immediately adjacent
the anilox roll. The sub-frame has portions for clamping the
doctor blade in place on the holder and bearing against the
anilox roll. The invention makes it possible to equip the
movable holder with the blades at either the press or at a
location remote from the press -- but in any event, quickly
install the blades thereby avoiding the laborious operations of
the past.
Other objects and advantages of the invention may be
seen in the details of the ensuing specification.
BRIEF DESCRIPTION OF DRAWING:
The invention is described in conjunction with
illustrative embodiments in the accompanying drawing, in which
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FIG. 1 is a perspective view, somewhat simplified, of a
portion of a flexographic press;
FIG. 2 is a side elevational view of certain of the
3~8 ~ .
elements of FIG. 1 as they would be disposed during "inking" of
the anilox roll;
FIG. 3 is a fragmentary perspective view of the
apparatus of FIG. 2;
FIG. 4 is a view similar to FIG. 2 but with the
subframe pivoted away from the anilox roll preparatory to doctor
blade replacement;
FIG. 5 is a view similar to FIG. 4 but with the doctor :~
blades unclamped for ease of replacement; :
FIG. 6 is a fragmentary perspective view of the
apparatus of FIG. 4; ;~
FIG. 7 is a fragmentary side elevational view of a
modified version of the invention featuring a removable holder;
FIG. 8 is a sectional view taken along the sight line ~-~
8-8 applied to FIG. 7;
FIG. 9 is a view similar to FIG. 8 but showing the
parts in a different operating condition; ~ :~
FIG. 10 is a side elevational view, partially
schematic, of a flexographic press equipped with another
modified cartridge of the invention; and
FIG. 11 is a fragmentary perspective view of the
cartridge portion of FIG. 10.
DETAILED DESCRIPTION~
In the illustration given and with reference first to
FIG. 1, the numeral 20 designates generally a fragment of the
frame of the flexographic press. A similar fragment is seen in
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331)8
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FIGS. 3 and 6. Other details of the frame are omitted for ease
of presentation but additional details can be seen in co-owned
Patent 5,012,736. -;
The frame 20 rotatably supports an anilox roll -
generally designated 21 which can be considered an ink transfer
roll of the type described in greater detail in the
above-mentioned 5,012,736 patent. Movably mounted on the frame
for coaction with the anilox roll 21 is a subframe generally
designated 22 and which is seen to be essentially C-shaped in
side elevation. Still referring to FIG. 1, it is seen that the
subframe 22 carries fluid pressure cylinder means 23. These
cylinder means in turn carry the blade-mounting holder 24. The
holder 24 is equipped with an upper doctor blade 25 and lower
doctor blade 26. These blades, along with end seals 27 (only
one seen at the left of FIG. 1), holder 24 and anilox roll 21
define an ink chamber 28 (see FIG. 2).
In normal operation, ink is contained in ink pail 29
and is delivered through supply line 30 by motorized pump 31.
The ink enters a lower port 32 in the holder 24 and the excess
exits from an upper port (not shown) through the return line 33
to the pail 29.
FIG. 2 shows the orientation of the just-described
elements during "inking", i.e., printing. At that time, the
doctor blades 25, 26 are firmly clamped to the holder by the
subframe 22. More particularly, the ends of the subframe
adjacent the anilox roll 21 are equipped with a top clamp
33~
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blanket 34 and a bottom clamp blanket 35 -- see the right and
central portions of FIG. 5. These blankets extend the length of
the blades -- see for example, the blanket 35 in FIG. 6. A
plurality of cylinders 23 are provided along the blanket length
for lmiform clamping pressure.
For blade replacement, the subframe 22 is pivotally
mounted on the press frame as at 36 and the pivoted "away"
position is seen in FIGS. 4-6. Then the holder is withdrawn
from the blankets 34, 35 by the cylinder means 23 -- see FIG.
4-
The pivot axis 36 is located on the frame 20 so that
both the edge of the lower doctor blade 26 and the part of the -
bracket 35 closest to the anilox roll 21 will clear the roll and ;
without the need for translating the subframe 22.
DOCTOR BLADE CHANGEOVER
This sequence is started with the doctor chamber inked
up at the end of a run, and the following steps performed:
1. Remove ink from doctor chamber by draining
through supply side hole line 30.
2. Pivot the doctor blade subframe 22 to FIG. 4
position to expose chamber. This is accomplished by backing off
the upper thumb screws 37 and manually pivoting the subframe
against a stop provided by the frame at 38 (see FIG. 6). There,
the pivot handle is designated 39 and is seen abutting the part
38 of the frame.
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3. Unclamp the doctor blades by retracting air
cylinder means 23 -- compare FIGS. 4 and 5.
4. Remove the used blades.
5. Wipe the remaining ink off of the anilox roll 21
and doctoring system, i.e., the holder 24, and seals 27, etc.
6. Replace the end seals 27 if needed.
7. Place new steel blades against magnets in the
doctor blade holder. The magnets can be best seen in FIG. 10.
In lieu of ferrous material blades-- as where plastic blades are
used -- a seating recess or shoulder can be provided.
8. Clamp the blades in place with air cylinder 23.
9. Pivot doctor blade chamber back to run position
and lock in place with the thumb screws 37.
10. The chamber 28 is then filled with ink and the
drive for the anilox roll is started. Any excess ink on the
- roll is caught in the ink pan 40 -- see FIG. 2.
The features/benefits of the invention are:
1. Time Saving -- the system pneumatically clamps
and unclamps blades without the use of any tools and fasteners
-- with approximately ten minutes saved per blade change.
2. operator friendly -- the blade holder 24 stays
in the press requiring only the handling of the blades and the
end seals.
3. Safer system -- Spent blades can be removed
prior to chamber washup.
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4. Compatibility -- Interchanges with previous ~
doctor blade holders with minimal changes. ~;
5. Ease of Cleanup -- Shallow chamber 28 with drain
system greatly reduces amount of ink in the chamber prior to
cleanup.
STRUCTURAL DETAILS
These are now described first with reference to FIGS. 3
and 6. Each of these fragmentary perspective views is generally '`~
in the direction of the arrow A as applied to FIG. 1. So, in
FIG. 3, the hose 30 is readily seen. So also is the handle 39
and cylinder means 23.
In FIG. 6, the same three elements are designated,
viz., 23, 30 and 39. Also seen clearly in FIG. 6 is the locking
pin 41. This is the pin held in place by thumb screw 37
compare FIGS. 2 and 4.
Referring again to FIG. 6, there is seen a slot 41a
provided in the frame 20 which receives the pin 41 when the
fountain is in the inking or printing mode. The pins 41 (one at
each end) are carried by an adapter bar 42 -- see FIGS. 4 and
5. The bar 42 is slidably mounted on the subframe 22 and ~ `
carries the holder 24 and the cylinder means 23. The piston rod
43 of the cylinder means 23 is attached to the bight portion 44
of the subframe 22 -- still comparing the right portions of
FIGS. 4 and 5.
E~30DIMENT OF FIGS. 7-9
Here like numerals are applied to similar elements but
-- 7 --
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with the addition of 100. In FIGS. 8 and 9 the numerals 121
designates an anilox roll. A holder 124 is provided which has
doctor blades 125 and 126 held on by magnets 145, 146 (see FIG.
9). The essential difference of this embodiment from that of
FIGS. 1-6 is in the provision of a different subframe generally
designated 122. However, as before, the subframe 122 and the
holder 124 make up the fountain and the subframe 122 is again
generally C-shaped.
Physically supporting the holder 124 is an L-shaped
bracket 147. The bracket 147 is slidably supported on rods 148
which constitute the lower legs of the C-shaped subframe 122
(see also FIG. 7). The rods 148 are rigidly fixed in the
subframe 122 and, more particularly to the bight portion 149 of
the generally C-shaped subframe 122. Pivotally mounted on the
upper end of bight portion 149 is clamp member 134 -- see the
extreme right of FIG. 9. Completing the C-shape is the bottom
clamp member 135 mounted on rods 148. Like their counterparts
in the embodiment of FIGS. 1-6, the members 134 and 135 clamp ~-;
the doctor blades 125, 126 against the holder 124 so as to
define chamber 128 (see FIG. 8).
As can be seen in FIG. 7 at the left hand end, the
bracket 147 is equipped with an end bore 150 which provides
journal 151. A similar arrangement is provided at the right
hand end (not shown) so as to rotatably support the overall
fountain assembly on the machine frame (not shown).
Once the holder 124 is desired to be replaced, the
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subframe 122 is retracted away ~rom the anilox roll 121. This
can be appreciated from a consideration of FIG. 9. This differs
from the showing in FIG. 8 where the fountain is in operational
position with the doctor blades 125, 126 bearing against the
anilox roll 121.
To proceed from the disposition of elements in FIG. 8
to that of FIG. 9, we both retract and rotate the holder 124.
Rotation occurs about the axis 151a of the journals 151 -- see
the lower center of FIG. 8. For this purpose, we connect the -
ends of the L-shaped bracket 147 to a suitable
retraction/rotation means such as a stepping motor driving a
screw actuator as seen in co-owned Patent No. 5,184,556.
Alternatively, the retraction/rotation means may be in the
nature of a pressure fluid cylinder, ball and screw arrangement,
etc. so as to retract the ends of L-shaped bracket 147 and also
rotate the same to the condition depicted in FIG. 9.
Either simultaneously with the foregoing movement or
shortly thereafter, the pancake cylinder 123 is energized to
unclamp the holder 124. For that purpose, the cylinder 123 is
rigidly mounted on the bight portion 149. The piston rod 150 of
the cylinder 123 extends through the portion 149 and is coupled
to the L-shaped bracket 147. As the piston rod is retracted
into the air cylinder, the bight portion 149 moves toward the '~
L-shaped bracket 147. This unclamps the lower blade 126 from
the angled surface of the member 135 (see the upper left center -~
of FIG. 9).
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For unclamping the blade 125 from the clamping surface
on the member 134, the member 134 is pivoted by the withdrawing
action of the piston rod of the cylinder 123. More
particularly, the member 134 is pivotally mounted as at 151 at
the upper end of the bight portion 149. As the piston rod 150
i8 retracted (going from the FIG. 8 showing to that of FIG. 9),
the bight portion 149 moves to the left and the number 134 bears
against and pivots on a mushroom-shaped button 152. This
unclamps the upper blade 125. The member 134 is urged back into
clamping position by the torsion spring 154 -- so that when
fluid pressure is removed from the cylinder 123, the spacing 153
moves the member 134 back to its FIG. 8 position. This occurs
by virtue of the torsion spring 153 being fixed at its lower end --
as at 153a and bears against a post 153b on member 134 at its
upper end.
MBODIMENT OF FIGS. 10-11
Again, the frame 220 supports an anilox roll generally
designated 221. Movably mounted on the frame for coaction with ~-
the anilox roll 221 is a subframe generally designated 222 and
which is seen to include two portions or members 254 and 255.
These members are pivotally interconnected at 256 and the member
255 can be pivoted to the position 255' shown in dotted line.
This is advantageously achieved through a pressure fluid -
cylinder 223 which is mounted on a clevis fixed to the member
254. The piston rod 257 of the pressure fluid cylinder is seen
to be equipped at its work end with an arm 258 rigidly connected
-- 10 --
to the upper member 255. Retraction of the rod 257 pivots the
upper member 255 to the 255' position and effectively unclamps
the holder 224.
It will be noted that each of the members 254, 255 is
generally L-shaped 80 as to provide parts for clamping the upper
doctor blade 225 against an angled clamp surface 258 provided as
part of an arm 259 which in turn is provided as part of the
holder generally designated 224. Thus, the holder 224 and
subframe 222 make up a fountain F.
In similar fashion, the lower member 254 clamps the ;-
lower doctor blade 226 against the surface 260 provided on the
holder 224. More particularly, the holder 224 is C or channel
shaped having the arms 259, 261 connected by a bight portion
262. Completing the closing of the fountain are end seals as at
227 in FIG. 11.
OPERATION
When the holder 224 is installed as seen in FIG. 10,
liquid to be taken up by the transfer roll 221 is introduced via
the conduit 263 into an inlet port in the member 254 and through
an aligned port in the holder 224. The member is recessed so as -
to accommodate the installation of an O-ring 264.
In similar fashion, another O-ring is disposed about
the outlet passage 265 in the member 254 which is aligned with
the conduit 266. This results in a liquid level as at 267 in
the ink chamber 228. The excess liquid, i.e., ink is returned
for recirculation.
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-- 11 --
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With ink in the fountain F, the cavities in the anilox
roll can be filled under the control of the upper doctor blade
225 -- assuming the rotation of the anilox roll to be in the
direction of the arrow applied thereto. With reverse rotation,
the doctoring is provided by the blade 226.
When holder replacement is indicated -- worn doctor
blades, change of liquid, etc., the fountain chamber 228 is
drained and the cylinders 223 actuated to pivot the member
255 to the dotted line position 255'. The member 254 is moved
relative to the frame 220 to space the fountain F from the
anilox roll 221. A suitable mechanism for this can be seen in
co-owned Patent No. 5,184,556. This permits the holder 224 to
be withdrawn from its mounting.
Then, at a site convenient to but generally remote from ~-
the flexographic press, the operator can install new doctor
blades 225, 226. These are mounted against the bearing surfaces
on the holder 224 and because they are normally made of ferrous
material may be advantageously held in place temporarily by use
of magnets 245, 246. ;~
While in the foregoing specification a detailed -
description of an embodiment of the invention has been set down
for the purpose of illustration, many variations in the details
hereingiven may be made by those skilled in the art without
departing from the spirit and scope of the invention.
