Note: Descriptions are shown in the official language in which they were submitted.
CA 02350547 2001-06-14
Stack Comprising a Plurality of Elongated Bags of Plastic Film that are Joined
to Each
Other, in Particular Such Bags Intended for Newspapers, and a Method and
Machinery for
Manufacturing These
The present invention relates, first, to a stack comprising a plurality of
elongated bags that are
of plastic film and joined to each other, in particular, such bags as are
intended for
newspapers, preferably with at least one additional pocket, with at least one
suspension
opening in the area of the insertion opening for the bag, and a suspension
element that is
joined to each bag in the stack so as to be removable therefrom.
Bags of the type discussed herein are used, in particular, to provide a large
measure of
protection against the weather for newspapers, magazines, or the like. Very
often, these
elongated bags incorporate an additional pocket in which a diskette or the
like can be
inserted.
As a rule, some 10 to 20 , at most 25, such bags are combined to form a stack
and are held
together by a cardboard handle strip. This handle strip, which serves as a
suspension element
can be secured at the edge of a tear-off tab by clasps.
CA 02350547 2001-06-14
For practical purposes, a stack up of this kind is carried by a newspaper boy
who, when so
required, and if this has not already been done, fills a bag with a newspaper
or magazine in
order that the filled bag can be torn off the stack and then placed in a
position that is
accessible to the recipient.
The use of three different materials, namely, cardboard for the handle strip,
metal for the
clasps, and plastic for the actual bag results in considerable recycling
costs, since these
materials have to be collected separately from each other. In addition,
manufacturing bags of
this kind is extremely difficult, so that in practice such bags can only be
manufactured at a
speed of some 40 to 60 cycles per minute.
It is the objective of the present invention to produce a stack comprising a
plurality of
elongated bags that are of plastic film, in particular such bags as are
intended for newspapers,
which are joined to each other, and which can be transported and handled
easily. In addition,
the present invention proposes a method for manufacturing bags of this kind
that can be
combined to form a stack, whereby a simple and cost-effective manufacturing
process is
made possible. Finally, machinery is to be created that to a large extent uses
familiar
assemblies and makes it possible to manufacture bags of the type discussed
herein at a
comparatively high cyclic rate.
From the standpoint of the product, the objective of the present invention has
been achieved
in that the suspension element is formed by a tear-off section of plastic film
that protrudes at
one end of the bag. This tear-off section can be formed, for example, from a
separate tab that
is welded to one wall of the bag in the area of the insertion opening,
essentially parallel to a
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line of perforations. The insertion opening can be closed advantageously by a
draw string or a
rain flap.
A further advantageous feature of the present invention is that the pocket is
attached to the
end of the bag that is opposite the insertion openings, and that on its filler
opening, which is
essentially parallel to the insertion opening, this pocket has a flap that
projects on one side.
If necessary, this can be made in one piece from the material used for the
pocket and can be
provide on its inner side with a strip of adhesive that can if necessary be
covered by a
protective strip.
From the standpoint of the machinery that is used, the present invention is
distinguished
mainly in that the device that is used to join the individual bags to each
other in the stack is
configured as a blocking machine and in that, in addition, a tab-strip supply
device is also
provided. The continuous feed of a tab strip makes it possible to achieve a
comparatively high
cyclic rate of, for example, 100 to 125.
This is further facilitated in that the device has two separator welding tools
that are arranged
transversely to the direction in which the web of plastic film is fed and
which can be moved
synchronously up and down, and in that, in addition, the collector that is
arranged after the
separator weld tools as viewed in the direction of feed of the plastic film
incorporates the
stack- pin belts of a stack-pin conveyor, in which the bags with the tab
strips are taken from
the stack belts, the bags being held by the pins on the conveyor belts as far
as the stack belts
and then discharged in the area of the stack-pin conveyor by a removal device,
and are then
blocked with each other in the area of the tab-strip.
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Preferred embodiments of the bags that are discussed herein are shown in the
drawings
appended hereto. These drawings show the following:
Figure 1: a newspaper bags that has been cut off and is used to contain a
newspaper and
a diskette;
Figure 2: different versions of the suspension area of the newspaper bag;
Figure 3: a stack made up of a plurality of bags as shown in Figure 1;
Figure 4a and 4b: a plan view of a machine used to manufacture newspaper bags;
Figures Sa and Sb: the associated side view;
Figures 6 to 10: additional, modified embodiments of the bag.
The bag 1 that is shown in Figure 1, which is of plastic film, has at its
upper end an insertion
opening 2 that extends as far as a lower bottom seam 3 of the bag and serves,
for example, to
hold a newspaper 4, a magazine, or the like. In the lower area of the bag 1
there is a pocket 5
that is similarly of plastic, for example transparent plastic, and is welded
to one wall of the
bag 1 by a welded seam 6. This pocket is used as an advertisement pocket and
can be used,
for example, to hold a diskette 7, as is shown in Figure 1. A flap 8 is
provided to close the
pocket 5, and this is arranged either in an extension of the bag 1, as is
shown in Figure 1, or it
can be formed from an offset extension of the bags material. In any case, the
flap is provided
with an adhesive strip 9 so that once the diskette has been inserted, the
pocket can be closed
off at the lower end. If the pocket is not used, the adhesives strip 9 can be
covered by a
protective strip (not shown herein).
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At the upper end of the bag, i.e., in the area of the insertion opening 2,
there is a line of
perforations 11 in the rear wall of the bag. A suspension element in the form
of a tab-strip 13
that is of plastic is welded essentially parallel to this line of perforations
by way of a welded
seam 12. The tab strip 13 incorporates a suspension opening 14 and, if
necessary, stack-pin
openings 15 and blocking points 16. A plurality of bags is combined to form a
stack 17 using
these blocking points 16, as is shown in Figure 3.
Figure 2 shows different suspension openings in the suspension element 13.
These are
configured depending on the purpose of the bag and their utility. Above all,
it is possible to
select the shape of the suspension element and/or the thickness of the
material that is used, as
is required.
Figures 4a and Sa show a supply station 18 that is used to feed a first web
19, a second web
21 for manufacturing the bag, and a supply device 22 for a web (not shown in
detail herein)
for manufacturing the pocket 5. In order to produce the appropriate, necessary
longitudinal
welded seams, the webs are passed along a first longitudinal welding machine
23 and a
second longitudinal welding machine 24. In addition, reference point 25 shows
an additional
feed station for the tab strips, which is not shown in detail in Figures 4a
and Sa. A strip
deflection system is shown at reference point 26. An adhesive-strip feed
station 27 and an
adhesive application station 28 are also provided. Beneath the adhesive-strip
feed station
there is a longitudinal perforating device 29, and a machine for punching the
holes in the
handle is shown at reference point 31.
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The machinery shown in Figure 4b and Sb is used for the further production of
the bag
according to the present invention. Essential for the present invention is a
transverse-cut
welding device 32 that incorporates two welding tools 33, 34 that are arranged
essentially
transversely to the direction of movement of the webs and can be moved
synchronously up
and down; the spacing between these two welding tools is equal to twice the
width of a bag
section of the web of plastic film. Thus, two bags can be manufactured in each
cycle of the
machinery.
In practice , the bag or the pocket can be filled by machine, although this is
not shown herein.
In order to achieve the comparatively high cyclic rate of at least 100 to 125,
a collector 35 is
arranged after the separating welding device 32; this is described in greater
detail below.
First, the collector has a conveyor 36 that extends on one side into the area
of a guide table 37
or of guide belts in the area of the transverse-cut welding device 32. The
conveyor 36 has
endless belts 38 that are routed about guide rollers. The belts can be
provided with pins that
can penetrate the edges of the bag when the bag is moved in the direction of
feed. By this
means, the bags can be moved into the area of a stacking pin conveyor 9 that
lies partially
beneath the transport device 3G. The bags on the stacking pins 41 of the
stacking-pin
conveyor can be moved off by a removal device (not shown in detail herein) and
gathered into
stacks. Before the bags that are stacked in packets are removed, they are
blocked together by a
blocking device (not shown herein).
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Figure 6 and Figure 7 show the configuration of the bag as a so-called draw-
string bag. Once
it has been removed from the stack 17, a bag of this kind can be closed at the
insertion
opening 2 by a draw tape or string 42.
Another alternative is shown in Figure 8 to Figure 10. In this embodiment, the
bag 1 can have
the insertion opening 2 closed by a rain flap 43 that is secured by an
adhesive strip 44.
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