Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02301428 2000-03-16
M.LE.0556.DE
DESCRIPTION
Stack consisting of a multiplicity of bags which are
connected to one another and are made of plastic film,
in particular vending machine bags, and also process
and apparatus for producing and filling bags of this
type
The invention is initially concerned with a
stack consisting of a multiplicity of bags which are
connected to one another and are made of plastic film,
in particular vending machine bags, having a filling
opening and a flap which is on one side and has stack
openings and at least one initial cutting point.
When continuously producing bags, it is
generally known to gather together in a collecting
apparatus a previously specifiable number of bags to
form so-called bag stacks. A suitable collecting
apparatus is, for example, a stud-type stack conveying
device having a stud-type stack conveyor chain which
moves in the horizontal direction and receives the
severed bags on stacking studs. The stack openings,
whose distance apart corresponds to the distances
between the stacking studs on the stud-type stack
conveyor chain, are punched into each bag. During the
production of the bag stacks it is furthermore known to
fix said stacks by means of a wicket, specifically in
such a manner that the limbs of the wicket are guided
through the stack openings in the flap part of the
bags. For this purpose, either the bag stacks are
lifted off the stacking studs of the stud-type stack
conveying device and placed with the bags, which now
rest loosely on one another, onto the limbs of the
wicket, or the limbs of the wicket are inserted into
hollow groove-like recesses in the stacking studs of
the stud-type stacking conveyor chain and the
particular bag stack is removed in this manner. In
order to stabilize the bag stacks and to protect them
against being damaged by the ends of the wickets as a
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plurality of bag stacks are being packaged together,
said bag stacks are laid between a front and rear cover
sheet and are additionally secured by securing washers
or rubber stoppers placed onto the limbs of the
wickets. All of these procedures are generally carried
out manually by an operator.
Apart from the considerable outlay on auxiliary
materials, it can be quite difficult to package and
transport bag stacks of this type because of the
unwieldy wickets.
Considerable disadvantages also arise during
the packing procedure, i.e. when filling a bag with a
product, for example with a loaf of bread or the like.
During the filling procedure, the wicket, which is
inserted through the punched-out stack openings, serves
to fasten the bag stacks in the packaging machine, for
example an automatic packaging machine. Since during
the packing procedure the inserted product, for example
a loaf of bread, is drawn off together with the bag
surrounding it, it follows that the filled bag is
conveyed linearly to a sealing device. The linear
drawing off of the bag with the inserted product not
only requires a bag which is precisely formed in terms
of dimensions, but a sudden initial tearing of the
initial cutting point, which is conventionally located
between the stack openings and the front edge of the
flap, also occurs in this case. The "frayed" edge
region of the flap not only makes the bag look
unsightly, but there is also the fact that the flap
surface is no longer readily suitable for securely
attaching sealing elements, such as sticky labels or
the like, and/or as a surface to print on or hold
information.
Finally, after all of the bags are filled, the
wickets have, if appropriate, to be transported back
again to the manufacturer, i.e. to the producer of the
bags, sorted according to size and, if appropriate,
processed so that they can be reused.
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The invention is based on the object of
providing a bag stack of the type mentioned at the
beginning which manages without complex auxiliary aids
and, as a result, can be handled, in particular packed
and filled, substantially more simply, and, moreover,
is distinguished by having an attractive exterior. At
the same time, a process is proposed by means of which
interconnected bags, in particular vending machine
bags, can be produced in a simple manner, with a good
appearance in the edge region, and can be filled
conveniently and neatly. Furthermore, the intention is
to provide an apparatus for producing and filling
interconnected bags, which apparatus manages without
complex auxiliary aids.
This object is achieved with regard to the
product by the initial cutting point being formed as a
tear-off perforation by perforation lines which in each
case run at an angle with respect to the filling
opening and delimit a corner section, and by at least
one interconnecting point interconnecting the bags in
the stack being arranged in each corner section.
A stack formed in such a way can be produced in
a simple manner, conveniently transported and just as
easily filled. The decisive factor for this is first of
all the fact that the wickets which are otherwise
required can be completely dispensed with. It is
possible, in particular, to organize the production and
further handling of the bags substantially more
cost-effectively, since the costs and, if appropriate,
the transporting of the wickets to and fro between the
packer and the manufacturer are omitted. It is merely
necessary in the packing region to separate the topmost
bag in each case rapidly and reliably from the bag
stack and in so doing to hold the bag in such an
opening position that the product (loaf of bread) can
be inserted in a trouble-free manner into the bag. In
the case of a filling procedure to be handled in
accordance with the process according to the invention,
this can be achieved by, in order to fill the topmost
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bag in each case of the bag stack, holding the bag at
least in the region of its filling opening and/or of
the flap, in such an opening position that the
perforation between the corner sections and the flap is
inevitably at least partially torn open and the bag is
thereby at least partially detached from the
interconnection in the stack.
It is expedient if the tearing open of the
perforation takes place before the product to be
packaged is inserted into the bag. This enables an
exact tearing off along the perforation lines to be
ensured in a simple manner.
The tearing open of the perforation by means of
the opening procedure can be exactly regulated, namely
by the configuration of the perforation lines, in
particular their angular position and/or strength
and/or their continuous or shortened extent between the
side wall and the front edge of the flap, and the
opening procedure during the filling of a bag being
coordinated with each other.
Furthermore, this manner of proceeding makes it
possible for the opening procedure to cause the
perforation between the secured corner sections and the
flap to be torn open, and also to cause the bag, which
is detached from the bag stack, to be held in the
opening position. In this manner, two functions are
solved by one procedure, namely firstly the tearing
open of the perforation, and secondly the securing of
the bag during the packaging procedure.
If the aim is to obtain exact tearing off,
particular attention has to be paid, among other
things, also to the securing and interconnecting of the
bags and of the bag stack. A particularly favorable
solution is produced if the interconnections provided
in the corner sections are designed as interconnecting
holes, and the bag stack is suspended and/or held via
these interconnected suspension openings during filling
of the bags.
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When the bag stack is suspended in such a way,
it is possible, in principle, to dispense with
particularly large punched holes as suspension
openings, as have hitherto been necessary for the
wickets, in the remaining flap. However, in order to be
able to collect the bags in a collecting device during
the production process, the stack openings are either
produced by pin holes, or else cross recesses are
punched into the flap in order to form the stack
openings.
With regard to the apparatus, the holding of
the opened bag and the tearing off thereof from the bag
stack in the filling station can be achieved in a
particularly simple manner if an expanding device can
be moved into a tear-off position effecting the only
and at least partial severing of the tear-off
perforation of the bag to be filled. The tear-off
position can preferably correspond to the opening
position which is necessary in order to insert a
product or a loaf of bread. In contrast to the previous
function of an expanding apparatus, which merely had
the task of forming the bag opening approximately
corresponding to the shape and dimensions of the
product to be packaged, the current expanding device
has two additional functions, namely firstly to secure
the bag during the packaging procedure, and secondly to
undertake the opening movement in such a manner that
the expanding elements cause the perforation to be
broken open completely or virtually completely.
Finally, the holding of the bag stack in a
packer is assisted by a clamping plate being provided
below the plane of movement of the expanding elements
of the expanding device, and finally an adapter being
used which has holding rods, at a distance from the
interconnecting holes of the bag stack, and, with the
interconnection of a transverse bracket, has fastening
rods whose distance apart and diameter correspond to
the dimensions of the limbs of a conventional wicket or
receiving spikes of the packaging machine. The use of
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this adapter has the substantial advantage that the
conventional packaging machine or automatic packaging
machine, as was previously used for the insertion of
wickets, hardly needs to be changed, if at all.
In addition, the use of an adapter gives the
option of designing the lengths of the holding rods in
such a manner that a plurality of comparatively large
bag stacks can be stacked one above another, so that
there is overall a noticeable increase in productivity
during packing.
Preferred exemplary embodiments of the
invention are illustrated in the drawing and are
described in more detail below. In the drawing:
Figure 1 shows a bag stack forming part of the
prior art and having a wicket,
Figure 2 shows a bag stack consisting of bags
according to Figure 3,
Figure 2a shows an illustration corresponding
to Figure 2 of a bag stack consisting of bags according
to Figure 3a,
Figure 3 shows a first design of a bag,
Figure 3a shows a modified design of a bag,
Figure 4 shows a schematic side view of a bag-
producing machine,
Figure 5 shows a plan view of a filling station
with a preassembly station of a packaging machine (not
illustrated in detail), for example an automatic
packaging machine,
Figure 6 shows a perspective illustration of
part of a packaging apparatus of the filling station,
Figures 7 to 9 show details of a packaging
procedure,
Figure 10 shows a ready-packaged bag,
Figure 11 shows a detail in the sealing region
of a packaged bag,
Figure 12 shows a perspective illustration of a
bag stack with an adapter receiving said stack,
Figure 13 shows a modified design of the
adapter with a plurality of bag stacks,
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Figure 14 shows a plan view of a plastic film
web for producing double-film web sections, and
Figure 15 shows a delivery device in the form
of a stud-type stack conveying device with a double bag
stack.
According to Figure 1, a bag stack 1 has, in a
conventional manner, in the region of flap 2 stack
openings 3 through which a wicket 4 is inserted. With
the aid of the wicket and rubber stoppers (not
illustrated) which are pushed onto its limbs 5, the bag
stack can be held together reasonably well.
Each bag has a filling opening which is
indicated by 6 and by which the bag can be filled with
a product, for example a loaf of bread or the like, in
a manner described further below in more detail. The
flap 2 has an initial cutting point 8 in each case in
the region between the stack openings 3 and a front
edge 7 of the flap 2.
A bag stack 1 according to Figure 1 is
conventionally fitted with the wicket 4 in a collecting
device, and together with said wicket and further
auxiliary aids, such as the rubber stopper, cover
sheets etc., is packaged in cartons and supplied for a
filling operation.
With the aid of the wickets 4, the bag stack 1
is held in a packaging machine, for example an
automatic packaging machine, in such a manner that with
the assistance of air and/or suckers and an expanding
device, the topmost bag in each case of the bag stack
is brought into an opening position. The product to be
inserted, for example a loaf of bread, is pushed via
the filling opening 6 into the held-open bag with the
aid of a slider (not illustrated), for example. The
discharge force produced in this case causes the bag to
start to tear along the initial cutting point 8
provided in the region of the stack opening, and so the
bag comes free from the bag stack. Because the bag is
torn off linearly, the flap 2 is unable to have a
smooth front edge 7, i.e. the bag has an unsightly
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appearance because of the comparatively large
punched-out stack holes and the rip locations.
Figure 2 illustrates a first design of a bag
stack which is formed according to the invention and
has, in the region of the flap 2, corner sections 11
which are delimited by perforation lines 9 running
obliquely with respect to the filling opening 6. The
perforation lines 9 run continuously from the side
edges of the bags as far as the front edge 7 of the
flap 2. Located in the corner sections 11 are
interconnecting points 12 which are used to hold
together the bags, which consist of plastic film, in
the bag stack 1. The interconnecting points 12 are
designed as interconnecting holes and thereby offer the
option of suspending or holding the bag stack on a
holding device (described further below in more detail)
in the automatic packaging machine.
In order to collect the individual bags to form
the bag stack 1 in a collecting device of an automatic
bag-producing machine, use is made of stack openings 13
which are arranged in a central region, delimited by
the perforation lines 9, of the flap 2 and are formed,
for example according to Figure 2, by pin holes. This
means that the individual bags are speared on pins in
the collecting apparatus and in this manner are
initially held in the bag stack 1 in a positionally
correct manner before they are interconnected. Instead
of pin holes, the stack openings 13 may also be formed
by cross recesses 13', for example, as is shown in
Figures 2a and 3a.
Figure 3 illustrates, with reference to an
individual bag of the bag stack according to Figure 2,
that the perforation line 9 is not implemented as far
as the front edge 7 of the flap 2, but rather an
unperforated part remains which is indicated in
Figure 3 by S. This distance S can be varied, depending
on the discharge force in an automatic packaging
machine. Finally, the angle of the perforation line 9
can also be varied - as indicated by 9' - and finally
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so can the perforation, strength. Owing to these
conceivable changes of the corner perforation, it is
possible - as is explained further below in more
detail - for a certain initial tearing behavior of the
perforation lines 9 or 9' to be optimally determined.
A bag-producing machine 14, which is
illustrated in Figure 4, is suitable for producing bags
and bag stacks 1 according to the invention. The bag-
producing machine includes a supply stand 15 having a
winding roll 16 consisting of a thermoplastic film web.
The latter may, for example, be designed as a flat film
web 17. The flat film web 17 is guided within a
processing stand 18 (only indicated schematically) via
guiding rollers (not illustrated) which are
accommodated in it, and also via a folding device and
tension rollers. The processing stand 18 has a
bottom-fold inserting apparatus 19. A perforator 20 and
a cross-hole punching device 21 for making cross
recesses 13', for example, are arranged behind the
processing stand. The hole-punching device 21 is
followed by a transverse-weld severing device 22 and a
transfer device 23, which is finally adjoined by a
stacking apparatus 24 having a stud-type stack
conveying device 25. Finally, an interconnecting
station 26 is arranged in the region of the stud-type
stack conveying device 25. Said interconnecting station
can be adjoined by an unloading station (not
illustrated) for the interconnected bag stacks 1.
Figure 5 illustrates part of an automatic
packaging machine 27. The automatic packaging machine
27 has a preassembly station 28 which is mounted
upstream of a filling station 29 (explained in more
detail below) and serves to prepare bag stacks 1 for
filling. In the preassembly station 28, one or more
interconnected bag stacks 1, which lies or lie on a
support surface 31, are held by a holding apparatus 32.
The latter has a special adapter 33 which is described
in more detail in conjunction with the filling
procedure described below. The ready-prepared bag
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bundle is supplied to the filling station 29 in
accordance with arrow 34, and is deposited there on a
stacking table 35 which - as emerges from Figure 6 - is
designed such that it can be adjusted in height. In the
filling position, the bag stack bears with the flap 2
of the topmost bag of the bag stack 1 against a stop
plate 36 whose one, essentially horizontal, web 37
protrudes into the region of the flap 2 of the bags,
while the other web 38, which preferably runs
vertically to the web 37, of the clamping plate
constitutes, for example, a stop for the front edge 7
of the bags.
For the sake of clarity, the adapter 33, which
has already been mentioned above, is illustrated
separately from the bag stack 1 in Figure 6, although
it is actually plugged in the interconnecting openings
12 of the bag stack 1 with holding rods 39. The adapter
has a transverse bracket 41 which has fastening rods 42
arranged on its side facing away from the holding rods
39. The distance between, and diameter of, the two
holding rods 42 correspond to the dimensions of a
conventional wicket, as has hitherto been used in
automatic packaging machines for filling vending
machine bags.
The actual filling procedure is explained in
detail below with reference to Figures 7 to 9:
The automatic packaging machine includes, inter alia,
an air-blowing device 43 (Figure 7). Instead of blown
air, a suction device may also be provided.
Furthermore, an opening device having an expanding
device 48 is provided which has lower expanding
elements 49 and upper expanding elements 51 and - as
emerges from Figure 8 - can be inserted into the
preopened filling opening 6 of the topmost bag.
Expansion of the bag at least in the region of the
filling opening 6 causes the bag which is held open to
be severed from the bag stack along the perforation
lines 9 starting from the side edge of the bag
(Figure 9). The bag is held at the filling opening
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solely by the expanding elements of the expanding
device and in the region of the flap 2 by the web 37 of
the clamping plate 36. A product, for example a loaf of
bread 52, is inserted through the opened expanding
elements by means of a slider, indicated by the arrow
53, or a pair of tongs into the bag and the bag is then
supplied together with the loaf of bread to a sealing
device (not illustrated). Figure 10 shows the ready-
packaged bread package, where it can be seen, and also
from Figure 11, that the edge region of the bread bag
seal no longer has frayed edges and the package
therefore obtains a pleasing exterior. As the height of
the bag stack decreases, the stacking table 35 is moved
up against the clamping plate 36.
It can be seen from Figure 12 that the holding
rods 39 of the adapter 33 are substantially longer than
the fastening rods 42. This provides the option of also
receiving a plurality of bag stacks one above another
on the adapter 33, as is shown by way of example in
Figure 13.
Depending on the size and weight, in the case
of hygiene bags, instead of the wicket clamps fastening
sleeves, preferably made of plastic material, are used
per stack in order to bring the formed bag bundles
securely and in a targeted manner into the packaging
machine, in order to fill them there.
The bags or bag stacks designed according to
the invention mean that it is possible for the
fastening sleeves and their manual handling to be
omitted. A plurality of bag stacks can likewise be
inserted in the packaging machine one above another. As
a result, the automatic packaging procedure is
considerably less adversely affected than has
previously been the case.
Instead of cross recesses, it is possible, for
example, also for star-shaped recesses or the like to
be punched in. The crucial factor is that no material
waste occurs.
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A clamping device or, for example, fixed
supporting bolts of the automatic packaging machine are
also conceivable as the securing device for the corner
sections. The crucial factor is that during the opening
procedure of the bag to be filled, it is ensured that
said bag is held in a stretched manner, particularly in
the region of the flap.
In each case, two opposite individual bags 50'
are produced from a double-layered plastic film web 50,
which is indicated in Figure 14 by dash-dotted lines.
For this purpose, a strip can be cut out of the one
film layer symmetrically with respect to a central
separating line 54, so that the flange-like flap 2
remains in the other film web. Alternatively, it is
possible to cut open the, for example, tubular plastic
film web in the longitudinal direction and guide the
tubular film web in each case on both sides of the
central separating line 54 in such a manner that the
desired excess for the flap 2 likewise remains in the
one film web.
The individual bags, which are provided with
the corner perforation sections 11 and are severed
transversely from the web but are still joined
together, are suspended stackwise via stack openings 13
which are produced in the flap 2 and are formed by pin
holes of pins 55 of the stacking apparatus 24, which is
indicated in Figure 15 and is in the form of a
stud-type stack conveying device 25. After that, the
two opposite bag stacks 1 are interconnected via
interconnecting points 12, after which the double bag
stack is divided into two bag stacks 1 by a separating
cut along the separating line 54. If the
interconnecting points 12 are designed as inter-
connecting holes, the latter can be used as suspension
openings for suspending the bag stacks in the automatic
packaging machine.
