Note: Descriptions are shown in the official language in which they were submitted.
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Device for wrapping packages.
The invention relates to a device for the wrapping
packages, such as mineral wool sheets or rolls and
comprising a conveyor on which the package is displaced, a
roll of film positioned at a distance above and below the
conveyor device, a welding bar and a striker bar, which can
be brought towards one another in such a way that between
them, the ends of the wrapping can be clamped and welded
together, and wherein a cutting device for cutting the
formed transverse weld in a manner such that ends of the
wrapping and the ends of the films which can be separated
while welded together.
Devices of the above-mentioned type are known in
practice. They operate in such a way that package, for
example, packages of mineral wool sheets stacked on top of
each other, are supplied in rows, one after another, by
means of a conveying device. The ends of the films, which
can be pulled or unrolled from an upper and lower roll of
film, are joined together by a weld so as to form a
curtain. The package unit in question is then moved
against this curtain so that sections of film are pulled
from the upper as well as the lower roll of film. The
package keeps moving and takes along the film until it has
moved over a striker bar. The package, for example, the
package of mineral wool sheets, then stops at a distance of
about 10 to 20 cm past the striker bar. At this point, the
package is wrapped on three sides, approximately in a U-
shape, by the plastic film. In this position, the welding
bar moves against the striker bar and pulls an additional
section of the plastic film from the adjacent roll of film.
In the striking position, an electric heater, located in
the welding bar, is heated so that a weld, running
transversely to the direction of conveyance, is formed.
After rapid cooling of the weld, the latter is cut in the
middle in such a way that in the first place, the package
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unit remains completely wrapped in the plastic film and in
the second place, the ends of the sections of film, on both
sides, unrolled from the rolls of film, are welded together
so that a curtain is again formed. The welding bar then
returns to the starting position and the wrapping operation
can be repeated. Subsequent to this operation, the wrapped
package unit is led into a shrinkage tunnel, in which the
plastic film is heated in such a way and upon cooling
again, shrunk in such a way, that it fits tightly about the
entire circumference of the package. The film wrapping of
the ready packed package unit then has two welds, running
over the entire width. A shrink film, actually of a
polyethylene material, is used as the plastic film.
Such package units are generally extremely bulky. As
the plastic film is very slippery, the packages are very
difficult to handle. For storage, however, they have to be
stacked mostly by hand in large quantities, transferred to
trucks, unloaded again at the dealer or at the construction
site and finally transported again for use. During these
operations, the bulky package units have to be seized with
widely extended arms by the workmen in question, lifted and
carried further, in which case they often slip due to the
slippery plastic film and fall to the floor so that the
plastic film can be damaged
In contrast, a feature of the present invention is to
provide a device capable of producing a wrapping wherein
the package units are easy to handle.
The above mentioned disadvantages are solved in that
the welding bar and the striker bar, seen in the direction
of conveyance of the package unit, are designed so wide and
the welding bar is provided with at least two heating
~ones, spaced at a distance from one another, that a
carrying strap is formed on the periphery of the wrapping.
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The present invention is further characterized by a
package of mineral wool sheets or rolls with a wrapping,
which consists of a shrinkable plastic film and of which
the ends are joined together by a weld which forms a
carrying strap defined by a flange or flap extending
outwards.
Accordingly, from a broad aspect, the present
invention provides a device for wrapping a package of
mineral wool sheets or rolls. The device has a conveyor
for conveying the package. A roll of film is spaced a
distance above the conveyor and a further roll of film is
disposed below the conveyor. The welding bar and a
stricker bar are movable against one another for clamping
ends of films between them and forming a wrapping. A
cutting device is provided for cutting through a
transversely running weld at the ends of the films of the
wrapping. The films are pulled from the rolls of films by
the moving package. The device is characterized in that
the welding bar and the stricker bar, seen in a direction
of conveyance of the package, are of a predetermined width
and the welding bar is provided with at least two heating
zones which are spaced at a distance from one another so
that on the periphery of the wrapping, a carrying strap is
formed.
~ ccording to a still further broad aspect of the
present invention, there is provided a package of mineral
wool sheets or rolls having a wrapping which consist of a
shrinkable plastic film and of which the ends of the film
are joined together with a weld. The package is
characterized in that the weld defines an outwardly
extending flange defining a carrying strap.
A preferred embodiment of the present invention is
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described with reference to the accompanying drawings:
Fig. 1 is a side view of a device at a starting
operating position;
Fig. 2 is a side view of the device according to Fig.
1, but in an intermediate operating position;
Fig. 3 is a side view of the device according to Fig.
1 or 2 in an operating position during the welding
operation;
Fig. 4 is a side vi~w corresponding to Fig. 3, but
showing a modification of the device;
Fig. 5 is a side view of the device according to Fig.
4 in an operating position after completion of the welding
operation;
Fig. 6 is a top view on a wrapped package;
Fig. 7 is an enlarged partial cross-section view of
the carrying strap, and
Fig. 8 shows enlarged partial cross-section view along
cross-section line VIII-VIII of Fig. 6.
For the exemplified embodiments described herein, the
following, the same designations were used in each case for
components which are the same or operate in the same way,
so that the description relating to these apply to the
different illustrated embodiments. In the embodiment,
according to Figs. 1 to 3, two conveying devices 1, 2 in
the form of roller conveyors are provided. Instead of the
roller conveyors, other suitable conveying devices, for
example continuous conveyor belts, can also be used.
Between the two conveying devices, there is a stationary
striker bar 13, of which the upper striking surface is at
the level of the upper conveying surface of the conveying
devices 1, 2. Vertically, at a distance above the roller
conveyor 1, a roll of film 3 is provided. Another roll of
film 4 is likewise installed rotatably below the roller
conveyor 1. From the upper roll of film 3, a film 5 can be
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pulled and from the lower roll of film 4, another film 6,
in which case the rolls of film always turn in the
direction of the arrows 20 and 21. The ends of the two
sheets of film 5, 6 are joined together by a weld 7, which
runs at right angles to the plane of Fig. 1 and extends
across the entire width of the strip of film. Close to the
rolls of film, there are guide rolls 8 and 9 which are
arranged in such a way that the lower sheet of film 6
passes through a gap ~etween the conveying device 1 and the
striker bar 13.
In the starting operating position according to Fig.
1, there is on the roller conveyor 1, a package unit 14,
which in this exemplified embodiment consists of a stack or
a package of mineral wool sheets 15 stacked one on top of
another. Further, there is a welding bar 10 which, by
means of a rod 11, herein shown in a simplified form, can
be moved up and down in the direction of the arrow 12. The
travel of the welding bar 10 is also greater than the
height of the package unit 14.
In the operating position according to Fig. 1, the
welding bar is in its upper position. If now the package
14 or the stack of sheets is moved in the direction of
arrow 16, into the operating position according to Fig. 2,
a section of the sheets of film 5, 6 is pulled from the two
rolls of film 3, 4 so that in this operating position, the
bottom and the front end of the package, in the direction
of conveying, are first wrapped by the plastic film. In
the further operation, the welding bar 10 is moved over the
travel distance down to the striker bar 13, resulting in
the operating position according to Fig. 3. During the
travel of the welding bar, the strip of film 5 is lifted
from the guide roll 17. The package unit is wrapped on the
entire circumference by the plastic film.
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As illustrated in Figs. 1 to 3 a~nd also Figs. 4 and 5,
there is shown another embodiment and wherein , the welding
bar 10 and the striker bar 13, seen in the direction of
conveyance 16 of the package 14, are designed very wide.
The welding bar 10 is provided with at least two heating
zones 18, 19, spaced at a distance from one another. During
the welding operation, a carrying strap 23 is formed on the
peripheral edge of the wrapping 26. Advantageously, the
heating zone 18 can also be of a double design so that two
welds, spaced closely next to one another, are formed,
between which a cutting operation can be effected.
According to Fig.3, the section of film of the wrapping 26,
on the rear end, runs at an acute angle, shown exaggerated
for better clarity, so that there exists still a wedge-
shaped gap. After severing the package, the latter is
moved into a shrinkage tunnel (not shown) where the plastic
film is shrunk to fit tightly against the package over its
entire circumference.
In the embodiments shown in Figs. 4 and S, both the
welding bar 10 and the striker bar 13 are displaceable by
means of the rods 11 and 22, shown simplified, so that the
two bars meet each other approximately at halfway the
height of the package.
The cutting device, which is well known is either
combined with the striker bar or disposed separately and is
controlled in such a way that it becomes operative shortly
after the welds are made and after they are cooled.
Advantageously, the cutting device according to the
invention has at least one additional tool for punching out
a grip opening in the carrying strap 23. In the embodiment
according to Fig. 6, three grip openings 27, 28 and 29 are
provided. For making the grips, three additional tools are
arranged in such a way to provide a central grip opening 28
and two edge grip openings 27 and 29, close to the edge of
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the carrying strap 23, (see Fig 6). The grip forming
tools have an oval cutting edge so that the grip openings
allow easy handling.
As illustrated in Figs. 6 to 8, the carrying strap 23
has weld lines 24 and 25 on opposed sides thereof. For
further reinforcement of the grip openings, an additional
oval weld 30 can be provided about their circumference. To
make this, the welding bar 13 has an additional oval
heating æone close to the edge of the respective grip
openings 27, 28 or 29. The sections of film inside the
grip openings can be punched out completely. But, it is
also possible to design the cutting edge of the additional
tool in such a way that it only extends over the two curved
sections 31 and 32 and an intermediate connecting edge 33
between the two curved sections so that the punched out
sections of film can be ~olded over the other, opposite
intermediate connecting edge 34. The folding can also take
place over the outer connecting edge 33 with an
appropriately reversed tool.
By means of the devices, described above, one obtains
a package unit of mineral wool sheets or alternatively also
of a roll of mineral wool, which is rolled together from a
sheet, with a wrapping 26 that consists of a shrinkable
plastic film and of which the ends are joined together by a
weld and in which case a carrying strap 23, pointing
outwards, is flanged on the weld. For manufacturing
reasons, the carrying strap 23, as was described above, is
formed from the extended ends of the plastic film sheet, in
which case the outer edge of the carrying strap 23 has
suitably in addition a further weld 24. The carrying strap
23 has one or several grip openings 27, 28 and 29 which,
for reinforcement, are surrounded by the welds 30. In
general, it is sufficient to provide just one single grip
opening at the centre. If, however, the package units are
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particularly large and heavy, the two outer grip openings
can be provided instead of the centre grip opening, or in
addition to this, so that two persons can handle the
package and especially for quick stacking and unloading.
In the case of a square or cubic package unit, the
carrying strap can be formed along one of its edges as
illustrated in Fig. 3. In the more suitable embodiment,
however, the carrying strap 23 is formed according to Fig.
5, disposed in the middle of a wrapped surface.
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