Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE INVE~TION
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This invention relates to printing presses of the
type in which the printing roll is provided with a
removable sleeve. These rolls are used e.g. in flexographic
printing for transferring an image to the substance being
printed~
BACKGROUND OF THE INVEMTION
Printing sleeves are removable from the rolls by
various known means, some employing air under pressure
(see U.S. Specification No.3146709) and others
radial expansion upon axial contraction 5see U.S.
Specification No.2450727). In particular there has
recently been proposed the use of rolls where the
core is of different diameters at its two ends, with
a corresponding difference on the interior of the
sleeve, with air pressure Vents from the core.
The use of such sleeves opens up the need for a
printing machine in which the sleeve removal can be
carried out in situ on the machine itself.
When a new image is to be printed a new sleeve is
provided and in the past this has meant the removal
of the complete roller from the printing machine and
~ its subsequent replacement after the sleeve has been -
; changed. It is further necessary to re-adjust the
contact pressures between the sleeve and the
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impression cyllnder and the sleeve and tne inking ..
roller. All of these operations are costly, both in ~ ;
terms of labour charges and of unproductive or down- ~ .
time of the printing machine~ -
: SUMMA Y OF THE INVENTION
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A considerable part of these expenses are avoided
if the printing sleeves of all types are changed
while the printing roll remains in the printing ..
machine and enabling this is the subject of the
present invention.
According to one aspect of the present invention
therefore, there is provided a printing machine having
at least one printing roll with a removable sleeve
which provides its printing surface, the roll being
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journalled in side frames of the machine one beyond
each axial end of the roll by bea:rings in the
respective side frames, the bearing in one of those
.~ frames being removable from the side frame and :
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irom the roll so as to allow for operations to be
. ~ 20 carxied out upon the roll from that axial end, and
. means beyond the other side frame for counterpoising
:~ ~ : tha roll when the ramovable bearing has been removed. :
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~;: In another aspect of the invention there is ~ :.
.`. provided a method of changing a sleeve upon a printing ;
~: roll which is borne in journals i.n a printing machine . .
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- : which consists of removing one only of the journals
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from the roll so as to leave that end of the
roll axially accessible, counterpoising the mass
of the roll by applylng downward pressure beyond
the other o~ the journals to an axl~ extendin~
from the roll, removing a sleeve from the roll
by axial movement over the said end of the roll,
replacing the sleeve by a fresh sleeve and repositioning
the first mentioned journal in the printing machine.
DESCRIPTION OF T~ DRAWINGS A~D OF A PREFERRED EMBODIME~T
~ particular embodiment of the invention and
method of carrying it out will now be descrlbed with :
reference to the accompanying drawings wherein -
Figs. 1,2 and 3 show in side elevation and partial`
section three successive stages in carrying out the
method, ;
Fig.4 is a side view, on a larger scale~ of a
counterpoising means,
Fig.5 is a sectlon of a removable journal, and
Fig.6 is a section~on the line VI-VI of Figure 5, -~
some parts being ur-ther cu~-away. `
~ ~ ~ Figure 1 shows diagrammatically the normal working
; ~ condition of a printing machine with a printing roll
~ 1 fitted with a demountable printing sleeve and in
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position in the printing machine, of which side
~rames are seen at 3 and 4 respectively. The roll 1
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has axles 5 and 6 which are journalled in side frame 3
and bearing block 7 borne on side frame 4. As will
be explained in more detail the bearing block 7 is
removable. Beyond the other of the journals is
provided conventional drive gear 8 and an extension 9
of the axis 6.
The sleeve 2 is of a type which is removable
from the roll 1 as is particularly valuable in
flexographic printing. In particular, the roll 1
may have ends of different diameters, with a ..
corre~ponding difference on the inner surface of the
sleeve and be provided with pneumatic rèmoval means ..
as has been described in the said co-pending
patent appl.ication.
To remove the sleeve 2 while the roll; remains
. in situ in.the p.rinting machine, the bearing block 7
is removed axially, a counterpoise for the mass of the ..
: . roll lk In a simple version, the counterpoise is a ` .
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~ ~ stop 10 in the form of a braclcet which is placed in
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position on the side frame of -the machine and bears
. downwardly on the axial extension 9. . . .
A stop 10 :i5 seen in dotted lines in Fig.2, for
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example.
. - ~ In a preferred system, a counterpoise is provided
. bv a hydraulic cylinder 12 piv~tally anchored to
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the machine rame/floor and acting through a pull rod
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13 and yoke 14, surrouncling -the ext.ension 9 of the
roll axle and engaged to it by a removable end-cap
15. The end-cap normally remai.ns permanently engaged
on the axle extension, and is rotatable within the
yoke 14 in roller bearing 16.
; A pivot 17 links the rod 13 to the yoke 14. The
rod 13 includes a turnbuckle 18 which is set so .
that, when pressure is applied within the c~linder
12 to drive the pis-ton 19 (coupled to the rod 13)
downwardly to its fullest extent (see Fig.2),
the roll 1 is maintained in substantially the same .
position as it.occupied when working~ but separated
by a small distance ~rom both impres.sion and inking
rol.lers, and with the driving gear 8 remaining in
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partial engagement with the gear trai~ as is normal :
when a printing mach.ine of this type is stationary. .
rrhen, as seen in Figure 3, an air-line 11 is brought up
to an air inlet provided in the end of the axial extension
9, air is passed to the hollow core of the roll 1 .
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escaping by apertures provided in its surface, and .~.~-
the sleeve 2 is slid axially off the roll over the
axle 5 r~he removal of the bearing block 7 has
allowed access to that end of the roll~ To fit a
sleeve~ all that needs to be done is the bringing up . .
of a fresh stage o~ the pneumatic means as described
in the said co~pendlng application, the returning
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of the bearing block 7 iIltO position and the
machine is then ready to work. 0~ course, the
present invention is equally applicable to any other
sleeve-removal systems which require free access
to one axial end of a roll core.
The removable bearing block is seen in more
detail in Figures 5 and 6.
The side frame 3 terminates in a separate block
20 which incorporates a rolling contact bearing 21
which runs on the journal 5. The bearing is axially
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immovable in the blocX. The blocX 20 is screwed down
onto the side frame 3 by long-stemmed bolts 22
engaging in threaded bores 22 in the side frame 3
and turnable by hand knobs 24. A spring 25 is
compressed between the undersurface of nob 24 and
an end of an enlar~ed housin~ 26 in the block 20.
For exact positioning oE the block 20 side walls of a
platform 27 on the side frame 3-engage tightly with
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side walls of respective ridges 28,29 on the block.
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- 20 Because the bearing block 20 must be axially
slldable off the roll ~ournal 5, the bearing 21
; has no axial retention capacity, its inner race
sliding freely on the journal 5. Axlal re-tention
capacity is~provided by an adjustable restrainer 30.
A rotatable shaft 31 is borne in a bore 32 in
the bloc7~ 20 5in Fig.6 the restrainer 30 has been
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removed). It is rotatable by hand knob 33 and is ~ ~
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axially immovable relative to block 20, being
retained by a shoulder 3A and collar 35. It is : :
screw-threadedly engaged at 36 with a restrainer
body 37. A locking screw 38 in the body 37 can
be tightened onto the shaft 31 to prevent it
ro-tating.
The body 37 has an apertured lug 39 which acts
as a yoke receiving within its circular aperture
40 a rolling contact bearing 41 which is axially
retained by circlip 42 and shoulder A3. An
extreme end portion of the axla 5 is made up of
an integral part 44 of a diameter to engage within
the bearing 41 and of a separate screw part 45 which
is screw-threadedly engaged with the shaft 5 by
means of a screw-threaded post 46. of the part 4
In the running condition of lhe machine a
shouldered washer 47 is clamped to the bearing 41
by screw part 4~. The axial position of the roll is
- adjusted by rotation of hand screw 33 and is locked
20 . by locking screw 38.
: ~ . To remove the journal (the machine being stopped)
- and after the counterpoise has been provided, -the~ -
screw part A5 is unscrewed and shouldered washer 47
: removed. ~earing 41 is now free to be slid axially :.
.~ ~ oEf the shaft part 44 and now the whole bearing block .~
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~ 20 may be removed, once bolts 22 have been undone.
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Bearing 21 offers no impediment to this removal.
Ihe bearing 41 is housed in a rlanged bush ~
of which the bush part 48 has an outer diameter 49
eccentric of its inner bore diameter 50, the lat-ter
being the diameter which receives the outèr race
of bearing 21. The flange 51 of the bush ~ has an -.
arcuate slot 52 by which a bolt 53 can locX the
bush ~ in a desired attitude, so that the .
eccentricity of the bush corrects for errors in
printing plates or sleeves on the roll, in a
manner known ~ se.
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