Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DEVICE AND METHOD FOR PACKAGING FLAT ARTICLES
CONVEYED IN A CONVEYING STREAM
The invention is related to the field of materials-handling and packaging
technology
and concerns a device and a method for packaging flat articles conveyed in a
conveying stream in accordance with the generic term (preamble) of the claims
1, resp.,
11. The device according to the invention serves for the packaging of flat
articles, for
example, of individual printed products, of stack-shaped groups of printed
products or
of stack-shaped groups of printed products and other flat articles, such as,
for example,
CDs, flat sample articles or flat sample bags.
From EP-A 0 712 782 or WO 2005/118402, for example, it is known how to pack
flat
articles of the type mentioned above with the help of a so-to-say endless
packaging
material web , e.g., a plastic foil or paper web fed-in from a roll. In doing
so, at least
one packing material web is placed around articles being conveyed in a row one
after
the other and at a distance from one another, or at least one packaging
material web is
fed-in on both sides to a row of this kind. Thereupon the packaging material
web is
closed transverse to the longitudinal direction with transverse seams between
two
successive articles respectively. Possibly in longitudinal direction on the
top of the
row or at its side longitudinal seams are also produced. In this manner the
articles are
enclosed by a closed - or only open in longitudinal direction envelope of
packaging
material. The enveloped articles, resp., the envelopes are normally separated
immediately after the establishment of the transverse seams or simultaneously
with it.
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In case of the utilisation of plastic foil as packaging material, the
longitudinal, resp.,
transverse seams are normally produced by welding, wherein it is possible,
that the
separation of the packaged articles is carried out simultaneously to the
establishment
of the transverse seams. In case of the utilisation of paper as packaging
material, for
example, immediately before the feeding-in of the packaging material web to
the row
of the articles to be packed at the points of the longitudinal -, resp.,
transverse seams an
adhesive activatable by heat is able to be applied to the packaging material,
so that the
seams then are capable by being established with similar means to the welded
seams
on plastic material packagings. It is also possible to close the seams by
means of
embossing or by other known methods known and adapted to the packaging
material.
For such processing operations like welding, gluing, etc., printed articles
are conveyed
in conveying streams to a processing station and conveyed onwards from it
again. The
processing station advantageously is equipped in such a manner, that the
conveying of
the packaged articles does not have to be interrupted for the processing, but
rather is
able to be operated continuously.
A problem in case of such devices with articles continuously conveyed in a
conveying
stream without any intermediate storage are the envelopes of packaging
material,
which because of a deficient supply remain empty, for example, when in a
regular row
of continuously supplied products one or several products are missing (gap).
In this
case, it is possible, that by transverse connections in the material web or in
another
manner envelopes are produced, which do not contain a product (empty
envelope).
The empty envelope is capable of disrupting the onward conveyance and the
further
processing of the enveloped articles, for example, if it because of the size -
and weight
differences is not gripped by the onward conveyor. This is particularly
applicable in
case of high processing - and conveying speeds of several thousand copies per
hour,
such as occur in the processing of printed products. Here there is the
increasing
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tendency to also protect printed products such as newspapers and magazines
with a
foil envelope.
The invention is based on the objective of making available a device and a
method for
the packaging of articles with a web of material, wherein empty envelopes are
not
capable of disrupting the further processing of the articles.
The objective is achieved with a device and a method with the characteristics
of claim
1, resp., 11. Advantageous further developments are described in the dependent
claims,
the description and the drawings.
The device comprises a conveying installation for conveying the flat articles
in a
conveying direction, a processing means for producing at least partially,
e.g., in
transverse direction, closed envelopes out of a packaging material with the
inclusion
of a product as well as a conveying onwards device.
In accordance with the invention, downstream of the processing means an
outward
transfer (removal) device is located. This is capable of removing empty
envelopes not
containing a product from the conveying stream. The empty envelopes are then
able to
be collected outside the conveying stream and disposed of. While the conveying
stream after the removal of the empty envelope has a gap, in contrast to an
empty
envelope, however, this gap does not represent a danger of disruption of the
further
processing and conveying. The gap in the conveying stream is able to be closed
again
by evening out.
Designated as conveying stream is the totality of all articles, which are
transported by
the conveying device, resp., the onward conveying device, resp., the spatial
zone
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covered by them during the transportation. It is limited in downwards
direction by the
conveying support, e.g., the conveyor belt of the feeding device, resp., the
conveying
plane defined by it. By deflecting from the conveying stream it is understood,
that the
empty envelopes are moved in such a manner, that their bottom side at least
partially is
not anymore in the conveying plane. Preferably, but not limited to, the
envelopes are
pushed upwards.
The conveying device in preference also transports a quasi endless packaging
material
web . In preference it is a belt conveyor. The articles preferably are
arranged in the
packaging material web or between two packaging material webs in such a
manner,
that they are covered by packaging material on both sides. The packaging
material web,
resp., a part of it, for this purpose is lying on the belt of the conveyor
belt. On it there
are the products, which in turn are covered with the packaging material from
above.
With a processing means, e.g., a welding element, transverse connections
between an
upper zone and a lower zone of the packaging material web are established, in
order to
produce a closed envelope of packaging material at least at a leading edge as
well as at
a trailing edge and to enclose and protect the product in this manner. The
onward
conveying device serves to convey onwards articles enclosed by such envelopes
of
packaging material; it is also possible that it is a component part of the
above
mentioned conveying device.
The conveying device may also be capable of serving as counter tool for the
processing means, or else it is also possible, that there are counter tools
moved
synchronous with the processing means. The processing means is moved up and
down
or also along a bent closed circulating track, for example, by being fixed to
a rigid
body or moved along rails. For producing transverse connections in a plastic
foil, in
preference a welding element, such as described, e.g., in WO 2005/118402 is
utilised.
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The transfer device may be able to grip and to remove the empty envelopes from
the
conveying stream, for example, by means of a movable mechanical element, which
is
controlled in a suitable manner.
In a preferred further development of the invention, the outward transfer
device,
however, only comprises construction elements arranged in a stationary way and
does
without movable parts. In preference these construction elements comprise
suction
and/or blowing devices, which operate continuously and/or in a controlled
manner.
With this, it is possible to realise shorter reaction times. As a result, a
complicated
mechanism and the driving of moving parts become unnecessary, which otherwise
would be necessary for implementing the required as short as possible reaction
time
(immersion into the conveying stream, gripping the empty envelope, removal of
the
envelope from the conveying stream, return to the starting position) of a
moving
mechanical element.
In preference the transfer device comprises a suction device, with which the
empty
envelopes are sucked from the conveying stream, e.g. in the manner of a vacuum
cleaner. The suction device preferably is operated continuously, wherein its
suction
power is such, that only empty envelopes are sucked up and transported away,
not,
however, those containing an article. The sucked up empty envelopes are in
preference
collected in a collecting basket in such a manner, that the suction power of
the suction
device is not impaired. As an alternative, the sucking up may only take place
when an
empty envelope is present.
Alternative to or in addition to the sucking up, empty envelopes in preference
are
deflected from the conveying stream with compressed air. By using compressed
air,
individual envelopes are able to be specifically influenced, wherein
nonetheless one is
able to do without movable mechanical components, which have to be
accelerated.
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The removed envelopes thereupon in preference, but not imperatively, are able
to be
sucked up by a suction device as already described. In this, by the deflection
it is
achieved, that the suction device with the same suction power is able to be
located at a
greater distance from the conveying plane. As a result, the susceptibility for
errors and
the passage height of the device (distance from conveying plane to suction
element)
and with this its flexibility for packaging articles of different thickness is
increased.
It is possible that the compressed air is continuous and calculated in such a
way, that
only empty envelopes are removed, but on the basis of their greater weight no
enveloped articles. In a preferred variant, the compressed air is supplied
under control,
when an empty envelope comes into the zone of influence of the outward
transfer
device, wherein the supply otherwise is interrupted. Herein it is possible
that higher
pressures, resp., outflow speeds are used and the empty envelope therefore is
very
easily deflected, resp., even blown away from the conveying stream.
As a variant to the pure compressed air supply, for the ejecting, for example,
a
pneumatically driven pusher is conceivable, which also makes a short reaction
time
possible.
For controlling the compressed and/or suction air supply, in preference a
control
system is present, which acts in conjunction with a detection device, in
particular with
an optical sensor. The detection device detects the presence of an empty
envelope in
the conveying stream, e.g., by measuring the optical transparency or by edge
detection,
and transmits a corresponding signal to the control system.
Overall a system for the outward transfer of empty envelopes is proposed,
which is
mechanically simple, is capable of operating with little control technology
effort and
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which comprises a low susceptibility for errors as well as a high flexibility
with respect
to the articles to be packaged.
Examples of the invention are depicted in the drawings and described in the
following.
These purely schematically illustrate:
Fig. I An overall view of a device in accordance with the invention, which
comprises a controlled compressed air nozzle as well as a suction device;
Fig. 2+3 a suction device utilisable in the device from Fig. I in two
different views;
Fig. 4 a detailed view of a catching basket.
Fig. 1 schematically illustrates an overall view of a device in accordance
with the
invention with a conveying device 24, a processing means 16, an onward
conveying
device 26 and a transfer/removal device 28.
With the conveying device 24, here a belt conveyor, articles 10 are
transported in the
conveying direction F lying on a lower material web 12 and covered with an
upper
material web 14. Upper and lower material webs 12, 14 normally are connected
with
one another. The articles 10 in the conveying direction F are at a distance
from one
another, wherein the distance of the leading edges of two successive articles
10 is
normally constant. On the basis of errors in the feeding-in, it is, however,
also possible,
that there are gaps in the conveying stream; the mentioned distance then
amounts to,
for example, double the normal distance.
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The processing means 16 serves to produce transverse connections 18 between
the
upper and the lower material webs 12, 14 and therefore to split-up the
packaging
material tube into individual envelopes (packages) 20 transverse to the
conveying
direction F, which here each respectively contain one article 10. The
individual
packages 20 are separated by lateral material displacement during or shortly
after the
production of the transverse connections, e.g., during the welding of a foil
seam. In
case of a gap in the fed-in conveying stream, an empty envelope 22 of
packaging
material is produced, because the processing means 16 also processes the
material
webs 12, 14 at a gap. It is possible that envelopes are produced, the length
of which is
greater than a typical product length, e.g., when several articles are missing
behind one
another and the transverse welding is interrupted.
The onward conveying device 26, which in preference conveys at a higher speed
than
the conveying device 24, serves to convey the enveloped products 10, resp.,
envelopes
in a continuous conveying stream. The filled envelopes 20 (resp., their bottom
sides)
15 are moved in a conveying plane E, which here, for example, is defined by
the
conveying support 26' (conveyor belt, conveyor strap) of the onward conveying
device
26.
The transfer device 28 serves to remove the empty envelopes from the conveying
stream. It is arranged downstream of the processing means 16 and here is
located in the
20 zone of the onward conveying device 26; it is also possible, however, that
it is
arranged between the conveying device 24 and the onward conveying device 26 or
in
the zone of the conveying device 24. The outward transfer device 28 comprises
a
controlled compressed air supply 30 as well as a suction device 40.
The compressed air supply 30 comprises a compressed air nozzle 31, a
compressed air
source 32, e.g., a compressor or a compressed air reservoir. The connection
between
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the compressed air nozzle 31 and the compressed air source 32 is capable of
being
specifically opened, resp., closed by means of a controllable valve 34. The
opening 31'
of the compressed air nozzle 31 is arranged in the vicinity of the conveying
plane E, so
that it is possible to specifically exert an influence on the conveying
stream. Here the
compressed air nozzle 31 is arranged in the zone between two partial
conveyors, out of
which the onward conveying device 26 is constructed. The distance between the
partial conveyors here is depicted exaggerated. Any element, which limits the
air
stream laterally, is capable of serving as compressed air nozzle 31, e.g.,
also a hole in a
supporting substrate of the onward conveying device 26. It goes without
saying, that
instead of air it is also possible to utilise another gas.
For controlling the compressed air supply, resp., the valve 34, there is a
control device
36. This receives a signal from a detection device 38, e.g., an optical
sensor, which
indicates the presence of a gap, resp., of an empty envelope 22 in the
conveying stream.
This signal makes the control system 38 enable the compressed air supply at
the point
in time, at which the empty envelope is being conveyed in the zone of the
compressed
air nozzle 31. Thereupon the empty envelope 22 is deflected from the conveying
stream in upwards direction.
The suction device 40 is located above the compressed air nozzle 31. It
operates
continuously. Its suction power and its distance from the conveying plane E is
selected
in such a manner, that empty envelopes 22 deflected from the conveying plane
are
sucked off and removed, not, however, products in envelopes 20. By the
compressed
air pulse therefore, with the same suction power the distance of the suction
tube
opening from the conveying plane E can be greater than without a compressed
air
pulse. The distance in preference is selected as so great, that a conveying
through or
away of products with a predefined maximum thickness is possible.
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The empty envelopes 22 are transported away through the suction tube 42,
collected
and disposed of The uninfluenced products 20 are conveyed on and if so
required
further processed.
The device demonstrated and described above is mechanically and control-wise
simple, is flexible with respect to the product thickness and operates
reliably.
An example for a suction device 40 is illustrated in Fig. 2 in a longitudinal
section
(vertical to the conveying plane E) as well as in Fig. 3 in cross section
(parallel to the
conveying plane E). The suction tube 42 already depicted in Fig. 1 leads into
a housing
44, which is capable of being closed air-tight, resp., into a catching basket
46 installed
in it. The cross section of the suction tube 42 may be round, rectangular or
shaped in
any other manner; it is also possible, that its area is smaller than that of
typical empty
envelopes 22, because these as a rule are capable of being deformed. The
housing 44 in
its bottom plane has a connection 54 for an under-pressure - / suction air
source 48,
which in an as such known manner, for example, comprises a blower 50 and an
exhaust air outlet 52.
The catching basket 46 is at least partially permeable to air and, for
example, as a
whole or partially consists of a perforated plate. The catching basket 46 here
is
dimensionally stable, it is, however, also possible that it is as a whole or
partially
flexible (net, bag).
Because of the following construction of the catching basket and of the
housing 44
explained in more detail with reference to Fig . 2 - 4 it is assured, that the
suction
power is maintained even if there are already empty envelopes in the catching
basket
46:
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The catching basket 46 consists of three sheet metal parts 60, 62, 64 arranged
in a
U-shape. The sheet metal parts 60, 64 form the side walls of the catching
basket 46 and
are located at a distance from the corresponding side walls of the housing 44.
The floor
surface 62 of the catching basket 46 is located at a distance from the floor
of the
housing 44 and therefore also at a distance from the connection 54 for the
suction air
source 48. In this manner it is assured, that suction air is able to get to
the suction tube
42 through the side walls 60, 64 of the catching basket 46, even when empty
envelopes
22 cover the as such permeable to air floor surface 62 and thus make it
impermeable to
air. The lower zone 46a of the catching basket 46 is permeable to air (e.g.,
consists of
perforated plate), while the upper zone 46b, in particular the zone around the
mouth 43
of the suction tube 42 into the catching basket 46, is impermeable to air. By
this it is
prevented, that empty envelopes 22 get deposited in the zone around the mouth
43 and
with this block the suction air supply through the suction tube 42.
The in the view in Fig. 4 rear and upper edges of the sheet metal parts 60, 64
adjoin the
housing 44, so that the catching basket 46 does not require a ceiling - and
back surface
of its own. The front of the catching basket 46 is open and here is located at
a distance
from the front of the housing 44 (not imperative), so that the empty envelopes
22 are
capable of being removed simply by opening the housing door 45.
