Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE AND METHOD FOR PACKAGING OF FLAT OBJECTS
The invention relates to a device and a method for packaging of flat objects,
in particular of
flat, bendable printed products, according to the generic term of the
corresponding
independent claims.
STATE OF THE ART
Devices for packaging of flat objects, in particular e.g. newspapers,
magazines, etc., into a
plastic sheet or film are generally known, e.g. from EP 1 751 005. With film-
wrapped
printed products such as magazines manufactured in this manner, the problem
arises of
supplementary products enclosed with the magazine sliding around inside the
film such
that their position is not defined. If such film-wrapped objects are stacked
they may slip in
relation to one another such that the stack becomes unstable and difficult to
handle.
EP 0 397 580 shows a handling device for bottles, which arrive in the device
partly
wrapped with shrink film. Grippers for holding the transported bottles are
provided, which
are designed for pivoting the bottles into a horizontal position. For this
purpose the bottles
must be stiff and they cannot be gripped in the region in which they are
covered by the
shrink film. The pivoting of the bottle into the horizontal position is
necessary in order for
the bottle to be heated regularly and longitudinally when entering a heating
channel for
shrinking on the shrink film.
DE 26 10 051 also discloses a handling device for bottles, which are partly
wrapped with a
shrink film. A specially shaped nozzle installation effects a selective
shrinking of a shrink
film in a first region, such that the shrink film, when transported further,
is fixed for
complete shrinking on.
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In both DE 26 10 051 and EP 0 397 580 the bottle is not completely wrapped by
the shrink
film, because on the one hand this contradicts the function of the shrink film
with relation
to the bottle, and in particular the shrink film covering the bottle's opening
would seal the
bottle there, which is not permissible.
EP 01718 198 shows a packaging device for manufacture of a shrink film
wrapping and
with subsequent shrinking but without the transporting of objects by means of
grippers.
DESCRIPTION OF THE INVENTION
It is thus the object of the invention to create a device and a method for
packaging of flat
objects of the named kind, which removes the above named disadvantages. A
further
io object is to create a method for packaging of flat, bendable objects, which
does not deform
the flat objects.
This object is achieved by a device and a method for packaging of flat objects
with the
characteristics of the corresponding independent claims.
The method for packaging of flat objects, in particular of flat, bendable
printed products,
comprises the following steps:
^ completely wrapping successive flat objects with a film wrapping by means
of a film wrapping unit;
^ gripping completely wrapped flat objects (for which purpose they are
individualised, or separated) each with a gripper of a first conveying device;
^ transporting the wrapped flat objects by means of the first conveying device
to a shrinking unit, wherein the shrinking unit is spatially separated from
the
film wrapping unit;
^ shrinking the film wrappings onto the flat objects by means of the shrinking
unit.
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The flat objects are thus are (indirectly) gripped through the wrapping.
The device for packaging of flat objects correspondingly comprises: a film
wrapping unit
for wrapping of succeeding flat objects with a film wrapping; a first
conveying device for
gripping the completely wrapped flat objects each with a gripper and for
transporting the
completely wrapped flat objects to a shrinking unit, wherein the shrinking
unit is spatially
separated from the film wrapping unit; wherein the shrinking unit is designed
for shrinking
the film wrappings onto the flat objects.
Thus it becomes possible to spatially separate the film wrapping unit from the
shrinking
unit, due to which again a more flexible design of the system becomes
possible. For
example the distance between the film wrapping unit and the shrinking unit is
at least 2
meters or at least 10 meters. Furthermore it also becomes possible to
subsequently equip an
is installation with a shrinking unit by integrating it into a consisting
transport line.
When shrinking the film wrappings onto the flat objects either the flat
objects are held and
transported by means of the grippers of the first conveying device, preferably
in a vertically
hanging position, or they are handed over to a second conveying device before
the
shrinking of the film wrappings. While shrinking the film wrappings the flat
objects are
transported by means of the second conveying device. Thus it is possible to
adapt the
second conveying device to constructional conditions of the shrinking unit
and/or to
prevent a detrimental strain on the first conveying device caused by the
shrinking unit.
Preferably after shrinking the flat objects are transferred back from the
second conveying
device to the first conveying device. The transferring of the flat objects
from the first to the
second conveying device is preferably laid out such that it may be switched on
and off.
Thus it is possible to lead only individual chosen flat objects into the
shrinking unit and not
to subject the remaining flat objects to shrinking. With an increasing
individualisation of
printed products this makes it possible to individually respond to the
necessity of a
shrinking depending on the number or the size of the object and of
supplements.
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In a preferred embodiment of the invention an excess size of the not yet
shrunken film
wrappings and the parameters of the shrinking (in particular time and
temperature) are
matched such that the film wrapping after shrinking is free of tensile stress,
i.e. that a
tensile stress in the film wrapping is substantially zero. Thus it is
prevented that a flexible
printed product is contracted by the tensile stress of the film wrapping and
is bent or
crimped.
In a preferred embodiment of the invention the conveying device runs in at
least one
section between the film wrapping unit and the shrinking unit on a course
above head
height and/or is fastened to a ceiling of a building. The conveying device
thus runs at least
2 to 3 meters above ground level. Thus the conveying device is arrangeable
such that it
does not collide with other units or passages. Preferably the shrinking unit
is hereby also
arranged above head height and/or on a ceiling of a building. Thus an even
more space-
saving design of the installation is made possible.
In an alternative preferred embodiment of the invention the shrinking unit is
arranged
below head height and the first conveying device or a second conveying device
conveys the
flat objects from the height above head height to the height below head
height. Thus the
accessibility of the shrinking unit is improved, though more space is
required.
Further preferred embodiments emanate from the dependent claims. Hereby the
characteristics of the method claims and those of the device claims may be
correspondingly
combined.
SHORT DESCRIPTION OF THE DRAWINGS
In the following the object of the invention is explained in more detail on
the basis of
preferred embodiment examples, which are shown in the enclosed drawings.
Hereby, in a
schematic manner:
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Figure 1 shows an overview of a device according to the invention;
Figures 2 and 3 show further variants for feeding a shrinking unit; and
Figures 4a and 4b show an object wrapped in film before and after shrinking.
The reference numerals in the drawings and their denotations are summarized in
the list of
reference numerals. In the figures identical parts are basically denoted with
identical
reference numerals.
WAYS FOR CARRYING OUT THE INVENTION
Figure 1 shows an overview of a device according to the invention. A film
wrapping unit 1
io is installed for wrapping a sequence of flat objects 5. These are
subsequently completely
wrapped by a film wrapping 6, transported by grippers 4 of a first conveying
device 2 to a
shrinking unit 3 and through the shrinking unit 3.
The shrinking unit 3 heats the film wrapping for shrinking, e.g. by means of
thermal
radiation or by means of heated air, which is heated by means of electric
energy or gas or
oil and blown onto the wrapped flat objects 5.
In Figure 1 the shrinking unit 3 is shown arranged above head height. Figure 2
shows a
further variant for feeding a shrinking unit 3, in which the shrinking unit 3
is mounted at
ground level and the first conveying device 2 is lead from a course above head
height back
down to the height of the shrinking unit 3.
In Figures 1 and 2 the first conveying device transports the flat objects 5
with the grippers
4 through the region of the shrinking unit 3. Hereby the shrinking unit 3 is
preferably
designed to heat the flat objects 5 and the film wrapping 6 to a lesser degree
in the region
of the grippers 4 than in other regions of the flat objects 5 or the film
wrapping 6.
In a preferred embodiment of the invention the shrinking unit 3 itself
comprises additional
gripping means or retainers 4' (shown diagrammatically and in broken lines).
These are
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arranged and activated for intermittent holding and transporting of the flat
objects 5. The
additional retainers 4' hold and transport the flat objects 5 for a determined
length of time
in a transport section of the shrinking unit 3 synchronously with the grippers
4. The
additional retainers 4' e.g. hold the objects 5 from one or from both sides or
from above,
but next to the gripper 4. The gripper 4 of the conveying device 2 temporarily
releases the
flat objects 5 within this length of time. Thus it is possible to better
expose the sections of
film 6 held and covered by the grippers 4 to the heat of shrinking unit 3 and
to shrink them.
Figure 3 shows a second variant for feeding a shrinking unit. In this variant
a second
conveying device 7 is arranged for transporting of the flat objects 5 through
the region of
the shrinking unit 3. A transfer device 9 is arranged for transferring the
flat objects 5 from
the first conveying device 2 to the second conveying device 7 and a pick-up
device 10 for
taking up the flat objects 5 onto the first conveying device 2 from the second
conveying
device 7. The second conveying device 7 thus forms a bypass 8 or detour from
the first
conveying device 2 through the shrinking unit 3. The second conveying device
e.g.
comprises a conveying belt 11 for transport of the flat objects through the
shrinking unit.
In a preferred embodiment of the invention the conveying belt 11 is followed
by a further
conveying means, in particular a further conveying belt 11', which transports
the flat
objects 5 further. In addition a switchable diverting device may be provided,
which,
selectively guides the stream of conveyed objects 5 back to the conveying
device 2 or
leaves them on the further conveying belt 11'.
Preferably the transfer device 9 may be switched on and off, wherein when the
transfer is
switched on the flat objects 5 are transferred to the second conveying device
7 and when
the transfer is switched off the flat objects 5 are transported onward by the
first conveying
device 2. The switching on and off of the transfer device 9 is coupled to a
coordinated, i.e.
delayed in correspondence to the transport speed, switching on and off of the
grabbing
device 10.
Figures 4a and 4b show a film wrapped object 5 held by a gripper 4 before and
after
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shrinking. In Figure 4a the film 6 lies relatively loosely around the object
5. In Figure 4b
the film 6 is shrunk onto the object 5 and lies tightly around it, preferably
with little
tension, such that a bendable object 5 is not bent by the tension of the film
6.
REFERENCE NUMERALS
1 film wrapping unit
2 conveying device
3 shrinking unit
4 gripper
4' additional retainers
5 flat object
6 film
7 second conveying device
8 bypass
9 transfer device
10 pick-up device
11 conveying belt
11' second conveying belt
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