Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Translation of replacement pages annexed to the International Prelimin~ry
Fl~mination Report under PCT Article 36. The pages 2/1 to 2/11 and 2/13
to 2/17 replace all of the original pages.
Replacement sheet
2/1
Apparatus for cutting across a paper web
This invention relates to an apparatus for cutting across a paper web, with
a stationary cutting tool which has cooperating cutter blades, with a first feeddevice arranged before the cutting tool and which is driven continuously during
operation of the apparatus, by means of which the paper web is fed between
two successive cutting operations by a prede~e~ ed length each time, with a
clamping device provided in the region between the first feed device and the
cutting tool and driven synchronously with the latter, by means of which the
region of the paper web immediately adjoining and lying before the cutting tool
can be clamped fast for the duration of the cutting operation, until the passagebetween the cutter blades is free again, and with a free space provided in the
region between the first feed device and the cl~mping device, into which the
paper web section continuously fed on by the first feed device during the
cutting operation can expand in the form of a loop bowed out transversely
relative to the theoretical straight feed direction.
In subsequent processing of printed paper webs, e.g. co~ ulel~ output, the
paper web has to be cut off into individual paper sheets with a printed form
height, which can lie between 3" and 12" for example. There exist automatic
cutting machines for this purpose which are equipped with cutting tools which
can cut off the perforated edges of the paper web or divide this in the
lon~ih~ n~l direction, in addition to a cutting tool which serves to cut across
the paper web. Such an automatic cutting machine which has previously been
found outst~nding in practice is described in the brochure of BOWE SYSTEC
AG, D-86135 Augsburg, "Schneideautomat B~WE 310" [BOWE 310
automatic cutting machine, 3/94]. This automatic cutting m~chine handles
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fan-folded printed paper webs. It comprises a cutting tool consisting of a
stationary cutter blade and a cutter blade which moves up and down for the
transverse cutting. A first feed device is arranged ahead of this cutting tool,
formed as a so-called tractor. This consists of two endless transport belts
arranged parallel to one another, which have pins eng~ging in perforations at
the two edges of the paper web. This known automatic cutting m~chine
operates according to the start-stop principle. While the cutter blades are
o separated from one another and the passage therebetween is freed, the tractor
feeds the paper web on by a length corresponding each time to the format
height. Then the tractor stops and the cutter blades of the cutting tool performthe cutting operation. As soon as the passage between the cutter blades is free
again, the tractor is started up again. Although the cutting rate of this known
automatic cutting machine is already pretty high at about 27,000 cuts per hour
with a printed form height of 3" (= 7.5 cuts/s), it no longer matches future
requirements. Modern data processing installahons operate with laser p~ lels
with such a high speed that the known automatic cutting m~çhine would no
longer be able to cut up on-line the paper web printed by the laser, i.e. at theoutput of the printer with a speed corresponding to the operating speed of the
printer. The operating speed of the known automatic cutting m~chines c~nnot
be increased substantially. This is imposed by the start-stop principle of the
system. The paper web has to be brought to a standstill before each cut and be
accelerated again after each cut from stationary up to the full feed speed, and
this more than 30,000 times per hour. The forces of acceleration acting on the
paper web at still greater cutting rates are so large
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that the edge perforations can tear off and if the paper web is provided with
5 transverse perforations, it tears at the transverse perforations.
An apparatus for cutting across a paper web of the kind initially recited is
known from DE-A 3 131 101, in which a second feed device is provided before
the clamping device, consisting of a continuously driven upper feed roller and alower feed roller which can be pressed on the upper feed roller from below and
o can be lowered away from ~e upper feed roller. The lowering movement of the
lower feed roller is effected synchronously with the drive of the clamping
device or the cutter blade, in a manner such that, before a cut the paper web isfirst clamped fast in the clamping device and at the same time the lower feed
roller is lowered. The paper web thus comes to a standstill and the second feed
15 device also no longer acts on the paper web. Since the first feed device feeds
continuously, the paper web jams up and a loop h~n~ing freely downwards
forms between the first and second feed devices. The cutting across is effected
by means of the cutting tool during the clamping of the paper web. After
completion of the cut the clamping is removed and the lower feed roller is
20 pressed against the upper feed roller of the second feed device. Since this
operates with higher feed speed than the first feed device, the loop formed
during the cutting across is pulled flat again. However, it has been found that
the loop formation no longer takes place in an orderly and reproducible m~nner
at higher paper feed speeds above 0.5 m/sec. and correspondingly a higher
25 cutting frequency. As a result of the chaotic conditions in the
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loop formation, cutting inaccuracies above all result in relation to the length of
5 the sheets of paper which are cut off, which lie outside the predelelmined
tolerances. Moreover a substantial amount of noise occurs from the rapid
sequence of loop formation and pulling the loop flat.
The invention is therefore based on the object of providing an apparatus
for cutting across a paper web of the kind initially referred to, in which a high
o cutting accuracy is obtained even at very high paper feed speeds and a high
cutting frequency, while the burden of noise is at the same time substantially
reduced.
This is achieved according to the invention in that a guide plate is
provided between the first feed device and the clamping device, in that the
15 guide plate is provided with a plurality of openings and in that the space above
the guide plate is enclosed by a damping hood, which is spaced from the loop.
The damping hood leads in combination with the guide plate provided
with openings to a great cutting accuracy even at very high paper feed speeds
and high cutting frequencies. Even with paper feed speeds above 0.8 m/sec.
20 and a cutting frequency of more than 10 cuts/sec., cutting accuracies in the
tenth of a millimeter range with a tolerance of ~0.3 mm are obtained. This is
attributable to the fact that the defined and constant air pressure conditions
exist inside the damping hood, which isolate the loop from ambient effects,
such as air ~ lellls, heat effects and the like during the loop formation.
25 Moreover vibrations of the loop are damped and through this
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ordered, reproducible loop formation is ensured. In this connection, the
5 arrangement of the guide plate provided with openings is also of importance.
The guide plate ensures that the loop can only form in one direction, upwards,
while the openings assume decisive importance. Thus, during the whirling out
of the loop, air can enter rapidly into the space between the loop and the guideplate but in particular the air can escape rapidly from this space again when the
o loop is pulled flat again by the second feed device, after completion of the
cutting operation. The invention makes it possible to increase the cutting rate to
about 80,000 cuts per hour with a printed form height of 3 ". Thanks to the highcutting rate it is possible to carry out the cutting across on-line at the output of
a laser printer, which contributes further advantages.
15 Advantageous emborliment~ of the invention are characterized in the dependent
claims.
The invention will be explained below in more detail, with refel-ellce to
several embodiments shown in the drawings, in which:
Figure 1 is a longitudinal section of the apparatus for cutting across a
20 paper web,
Figure 2 is a partial lon~ 1in~1 section of this apparatus in the region of
the loop formation to a larger scale,
Figure 3 is a partial plan view in the direction III in Figure 2.
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The apparatus for cutting across a paper web according to the
embodiment shown in Figures 1 and 2 comprises a cutting tool 1 with a
5 stationary cutter blade 2 and a cutter blade 3 which can move up and down. A
first feed device 4 is provided, spaced before the cutting tool 1 and is in the
form of a so-called tractor in this embodiment. The tractor consists of two
conveyor belts S arranged parallel to one another, whose pins 6 engage in
perforations at the two sides of the paper web 7. The feed device 4 is driven
o continuously with a peripheral speed Vl, which corresponds for example to the
discharge rate of a preceding laser printer, not sho~n. In the region between
the feed device 4 and the cutting tool 1 there is provided a clamping device 8
driven synchronously with the latter. This clamping device 8 is preferably
arranged in the vicinity of the cutting tool 1, i.e. its distance from the cutting
15 tool 1 is smaller than its distance from the feed device 4.
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In between the clamping device 8, which will be described in more detail
below, and the cutting tool 1 a second continuously driven feed device 9 is
s preferably arranged directly adjoining the cutting tool, with its feed speed (=
peripheral speed) V2 greater than the feed speed Vl of the first feed device 4.
A third feed device 10 is advantageously provided after the cuffing tool 1
and is also continuously driven, namely with a feed speed V2 which
corresponds to the feed speed V2 of the second feed device 9.
o The clamping device 8 comprises two jaws 11 which are spaced from one
another in the transverse direction of the paper web 7 and of which only one is
shown in the drawing. These jaws 11 cooperate with a stationary bed 12. Each
jaw 11 is disposed on one end (the lower) of plunger 13 movable transverse to
the feed direction A of the paper web 7, the other (upper) end carrying a roller14 which cooperates with a cam disc 15. The cam disc 15 can be driven in
synchronism with the cutting tool 1. To this end a common belt drive is
provided. The belt drive also drives the movable cutter blade 12. The drive of
the belt drive is advantageously effected continuously but it can also be
The drive speed n of the belt drive is so adjustable in relation to
the feed speed Vl of the first feed device 4 that
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a cut always takes place when the paper web 7 has been moved on by the feed
device 4 by a length corresponding to the desired format height (= printe~ form
5 height) relative to the cutting tool 1.
The second feed device 9 and the third feed device 10 advantageously
each comprise a continuously drivable feed roller 20 and 21 respectively and at
least one pressure roller 22, 23 axially parallel thereto, which bear under elastic
bias 24 on the feed rollers 20 and 21 respectively. The elastic bias 24 is
o preferably adjustable. The drive of the two feed rollers 20, 21 can be effected
by a third motor for example. This third motor imparts a feed speed V2 to the
feed rollers 20, 21 which is four times as larges as the feed speed Vl of the
first feed device 4 for example.
Furthermore a bowing out device 25 is provided between the first feed
15 device 4 and the clamping device 9 [8], which exerts a force P directed
transversely relative to the feed direction A at least intçrrnitt~ntly. If the feed
direction A runs substantially horizontally, as is the case in the embodiment
shown in Figures 1 and 2, tbe force P should be di~ected u~wardly. This has
the advantage that the advance of the paper web section 7a stored during the
20 cutting operation is also assisted by gravity after the release of the clamping
device 8, as will be described in more detail below.
In order to generate the force P in the first place there can be provided a guide
plate 26, which
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is bowed out transversely to the feed direction A relative to a plane E-E
tangential to the feed elements 5 of the first feed device 4 and the clamping
5 elements 11, 12 of the clamping device 8. In the embodiment shown the
bowing out 26a is upwards.
The manner of operation of the apparatus described above is as follows:
During the operation of the apparatus, the first feed device 4 is driven
continuously with a feed speed Vl and the second and third feed devices 9 and
10 respectively are driven continuously with a greater feed speed V2. The
movable cutter blade 3 can also be driven continuously, so that a cutting
operation and freeing the passage between the cutter blades 2 and 3 take place
alternately. While the latter case applies the clamping device 8 is also opened,so that the paper web 7 is moved on in the direction A by the feed devices 4
15 and 9 and also by the feed device 10 with greater format heights. As soon as
the paper web has moved relative to the cutting tool 1 by the set format height,the cam disc 15 presses the plunger 13 down, so that the paper web is clamped
fast between
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the jaws 11 and the stationary bed 12. The feed rollers 20, 21 of the second
- feed device 9 and the third feed device 10 carry on tllrnin~. The movable cutter
5 blade 3 moves down and cuts off a paper sheet 7b of the desired format height,which is moved on irnmediately by the third feed device 10. The feed rollers
20, 21 have a smooth, steel surface and the elastic bias 24 is so chosen that the
feed rollers 20, 21 can continue to turn during the clamping of the paper web,
without ~m~ging this.
While the paper web is held fast by the clamping device 8 for the duration
of the cutting operation, the first feed device 4 feeds the paper web on
continuously. This paper web section which is fed on is stored in the form of a
loop 7a bowed out transversely upwards relative to the theoretical straight feeddirection A. The bowing out is promoted by the bowed out guide plate 26 and
15 it is therefore ensured that the bowing out talces place in a predetermined
direction, namely upwards. During the bowing out a stress develops in the loop
7a, like in a kinked rod. When the passage between the cutter blades 2, 3
becomes free again on completion of the cutting operation, the clamping device
8 also opens, in that the region lSa of the cam disc 15 comes into the range of
20 the roller 14. As soon as the clamping device 8 has opened, the second feed
device 9 feeds on the end of the paper web adjoining the cutting device 1 with
a feed speed V2, which is higher than the feed speed Vl of the first feed device4.
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The stored loop 7a is caused to decay by this. The further movement of the
paper web section stored in the loop 7a is also promoted by the stress generated5 in the loop, which pushes the free end of the paper web on in the direction ofthe cutting tool 1. The loop 7a cannot expand to the rear because the paper web
is constantly fed on by the first feed device 4. In addition to the stress built up
in the loop 7a, gravity can also be effective in the embodiment shown, pushing
the loop 7a down and thus moving the paper web on in the direction towards
o the cutting tool 1. The second feed device 9 therefore only has to move on thesmall paper section 7a stored in the form of the loop, this ollw~-d movement
being promoted by the stress built up during the clamping and by gravity.
The holding fast of the paper web can also be effected in another way, for
example by clamping pincers which engage the edge of the paper web. What
s matters is merely that the clamping device is so driven synchronously with thecutting tool that the clamping device holds the paper web fast during the
cutting operation.
[There is no replacement page 2/12 for original page 12, since this was
cancelled in its entirety.]
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An important contribution to the increase in the cutting rate is given by
the formation of the region in which the loop formation takes place, shown in
5 Figures 2 and 3. It has in fact been ascertained that, with paper feed speeds
from about 0.8 m/s (which corresponds to about 38,000 cuts per hour with a
printed form height of 3"), unacceptable fluctuations in the cutting accuracy
arise. In order to achieve an adequate cutting accuracy in the range of tenths of
a millimeter, e.g. in the range +0.3 mm in spite of higher feed speed and higherlO cutting rates,
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it is advantageous to make use of the features described below in combination.
The guide plate 26 is bowed upwardly, where the bowing is obtained by a
s bend 26b in the guide plate. The guide plate 26 is furthermore provided with aplurality of openings 36, e.g. circular holes. Air can enter rapidly between theloop and the guide plate through these openings 36 during the bowing of the
loop but in particular the air can escape rapidly from the space between the
loop 7a and the guide plate 26 when the loop is pulled flat again by the second
o feed device 9 after completion of the cutting operation. The paper web 7 then
comes into contact with the bend 26b. The result of the friction occurring at
this place is that the tension exerted on the paper web by the second feed
device cannot propagate fully to the first feed device 4.
Furthermore, deflector plates 37, 38 which affect the loop formation are
lS provided in the front and rear regions of the guide plate 26, as regarded in the
feed direction A of the paper, above the guide plate and inclined oppositely
towards one another. These deflector plates 37, 38 are fitted to assist uniform
loop formation. The effect of the deflector plates 37, 38 is that the loop
formation always takes place at approximately the same place and that the loop
20 does not wander forwards or backwards in the feed direction A. Above all the
loop formation is reproducible because of the deflector plates 37, 38. In order
to be able to affect the loop formation it is further advantageous for the
inclination of each deflector plate 37, 38 relative to the guide plate 26 to be
adjustable.
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To this end the deflector plates 37, 38 can each turn about an axis 39, 40
extending transversely to the feed direction A and can be fixed by a device
5 which is not shown.
Furthermore, the space above the guide plate 26 and above the deflector
plates 37, 38 is enclosed by an damping hood 41. The damping hood 41 should
be arranged a large distance from the loop 7a, so that there is enough air spacebetween the loop 7a and the interior of the damping hood. The damping hood
o functions on the one hand as an air chamber which damps the vibrations which
occur with the loop formation at high speeds and it serves on the other hand
also for sound insulation.
The features used together in the embodiment shown in Figures 2 and 3
lead to stabilization and reproducibility of the loop formation, which
15 experience has shown is a pre-condition for high cutting accuracy at high
cutting rates, with tolerances in the range of tenths of a millimeter.
