Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR PACKING ITEMS, LIQUID OR LOOSE
MATERIAL IN FILM BAGS, AND A BAG WEB
Field of the Invention
The present invention concerns a method for packing articles, liquid or loose
material
in film bags which are conveyed through a filling station in a continuous web
of bag
items, wherein the bag openings are kept open for reception of articles after
which the
bags are closed and separated from the web, by which method the bag web
initially
and along its opening edges is brought into guiding connection with guide
means
adapted for retaining and guiding peripheral areas at the opposing bag opening
edges
along a conveyor path through the filling station, as in connection with this
passage
the guide means force the bag opening edges apart for successive opening of
the bags
in the filling station, and then, after filling the bags, joining the bag
opening edges for
closing the bags, by which method the opposing bag opening edges are mutually
unfolded and by which method the bag web is brought to engage the guide means
by
being conveyed on a support rail, the guide means ensuring retention of the
bag web
along the conveyor path through the filling station.
The invention furthermore concerns an apparatus for performing such a method,
including:
- a filling station in which the bag openings are kept open for reception of
articles;
- guide means adapted for retaining and guiding peripheral areas at the
opposing outer
bag opening edges along a conveyor path through the filling station, as in
connection
with this passage the guide means force the bag opening edges apart for
successive
opening of the bags in the filling station, and then, after filling the bags,
joining the
bag opening edges for closing the bags again;
- a support rail for conveying the bag web for engagement with the guide
means.
The invention further concerns a bag web for use by such a method and in such
an
apparatus, the bag web including a contiguous series of bag items separated by
a
number of slits extending from a bottom edge of the web to a point below a
upper
edge of the web, the lateral edges of the webs being closed by welds, and
where the
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bag web includes a central support region extending longitudinally of the bag
web, the
support region connecting bag items that are disposed side by side
transversely of the
web.
Background of the Invention
A basic example of this technology is mentioned in EP-696997 in which it is
stated
that the opposite upper edge areas of the bag item web is made with bent
peripheral
parts formed by grooves for drawing in on conveyance bars which have a mutual
expansion for producing an opening of the bag items in the direction of
conveyance,
such that these can be filled, for example through a superjacent funnel,
whereafter the
conveyance bars are narrowed against each other again for temporary closing of
the
filled bag items. These may then be closed finally by welding below the said
duct
parts, after which these are cut off and the items are mutually separated. As
alternative
is specified that instead of the channel parts there may be used edge
thickenings that
may be received in slotted guide tubes for corresponding conveying of the bag
items.
Since then other types of means have been suggested for catching and carrying
the
opposite upper edges of the bag item web, for example as stated in EP 0 555
321 B
where special catching chains are used for the purpose without special
requirements to
the design of the upper edge areas of the folded bag item web. This is of
substantial
significance in that as an end product a simple rolled op flat film web
without local
thicknesses may be used, however in return there are considerable problems
with
regard to both the guidance of the opposite edges of the bag items for a safe
engagement with the chains and with regard to a desirably inexpensive
embodiment of
these chains.
In EP 0 396 838 and EP 0 825 116 it is furthermore stated that a flat pipe web
of the
film can be applied which can continuously be cut open along its upper edge
with
integrated unfolding and catching of the thus cut open upper edges without
these
being specifically designed neither as grooves nor with thickenings which will
indicate a distinct simplification of the requirements for the formation of
the bag web.
The cut up upper edge parts are unfolded for squeezing between respective
moved
belts, which are formed with longitudinal recesses and corresponding cords for
pressing in, whereby a suitably firm carrying engagement can be established.
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This engagement, however, is not more firm than axial slipping may occur
between
the upper edges of the bag web and associated belt conveyor means, whereby
uncertainty may arise as to whether a conveyed item has been conveyed entirely
synchronously with the conveyor belts. Furthermore, deviations with regard to
level of
the area of the web sides squeezed between the conveyor belts may arise, which
can
have significance to whether the filled bags are finally closed just on the
spot intended
for this purpose, e.g. with regard to print on the bag.
In EP 1 087 890 is described a technique which uses a simplified flat bag web
as said
opening edge is merely closed when the web is introduced on a single carrier
bar and
is continuously cut open in a station whereby the thereby upright peripheral
strip parts
are unfolded in order to be laid down on opposite chains. These strip parts
are made in
advance with a row of holes which are moved down onto upwardly pointed holding
studs on the carrier chains during folding down whereby a safe carrier and
propelling
engagement is achieved without any special profiling of the opening edges.
EP 1 451 069 discloses a similar technique. Here, edge strip parts will also
be made in
advance with a row of holes which are moved down on upwardly directed holding
studs on the carrier chains during folding down such that a secure carrier and
propelling engagement is achieved without any special profiling of the opening
edges.
Common to all these prior art systems, the bag web is conveyed with a series
of bag
items that are positioned in longitudinal direction and filled successively.
US 2003/0165278 A, EP 1733970 A, US 2004/0134166 A, WO 02/070349 A, and DE
3839336 A all disclose filling of various bag types in bag webs with two bag
rows
with a central extending support region running longitudinally of the film
web.
For many years there has been a wish for increasing the rate of filling and
for
producing the bags more cheaply. It is primarily a wish in connection with the
technology of the two latter European patents where the use of studs provide a
secure
carrier and propelling engagement. However, there is a similar wish in
connection
with the other described prior art techniques.
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Object of the Invention
It is the object of the invention to provide a method for packing articles,
liquid or
loose material in film bags, which in a continuous web are conveyed through a
filling
station that provides a high filling rate.
A further object of the invention is to indicate a bag web of bag items
enabling a high
filling rate and cheap production of the bags.
Description of the Invention
According to the present invention, this object is achieved by a method of the
kind
mentioned in the introduction, and which is peculiar in that the bag web is
provided
with a central support region extending longitudinally of the bag web, the
central
support region formed as an entirely or partially closed channel, and where
the central
support region connect bag items that are disposed side by side transversely
of the
web, the central support region being conveyed on the support rail along the
conveyor
path through the filling station, and that peripheral areas at the outermost
opposite bag
opening edges of two juxtaposed bag items are brought in guiding connection
with the
guide means.
An apparatus according to the invention is peculiar in that the support rail
extends
along the conveyor path through the filling station for supporting the bag web
at a
central support region extending longitudinally of the bag web and connecting
bag
items that are disposed side by side transversely of the web, as the support
rail is
adapted for being received in the entirely or partially closed channel in the
central
support region of the bag web.
A bag web according to the invention includes a central support region
extending
longitudinally of the bag web and connecting bag items that are disposed side
by side
transversely of the web, and which is peculiar in that the central support
region is
formed as an entirely or partially closed channel, and that the peripheral
areas at the
outermost opposite bag opening edges of two juxtaposed bag items are adapted
to be
brought into guiding connection with guide means.
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In a surprisingly simple way it appears to be possible to increase the filling
rate
significantly and at the same time reduce the price of producing and filling
the bags,
just by providing a bag web having bag items disposed side by side
transversely of the
web. The bag web thus appears with two juxtaposed rows of contiguous bag
items.
5 These two rows are connected with the central support region extending
longitudinally
of the bag web.
This central support region is supported on the support rail which is known
from the
technique in the two European patents EP 1 087 890 and EP 1 451 069. It is
only
necessary to extend such a support rail so as to extend along the conveyor
path
through the filling station for supporting the two juxtaposed bag webs in the
filling
station. Bag items from each of the two rows will be supported by the common
central
guide rail at their common central support region, and supported by the guide
means
at each of the peripheral areas at the outermost opposite bag opening edges of
two
juxtaposed bag items.
When the central support region is formed as an entirely or partially closed
channel, a
more secure guiding of the bag web is achieved. Furthermore is achieved the
advantage that different weights of the two juxtaposed bag items will not draw
the
web askew. By using a channel at the central support region it becomes
possible to fill
the two juxtaposed bags with different weight. They can also be filled at
different
times. The requirements for positioning of filling funnels and similar filling
equipment
will therefore be more flexible than in a situation where simultaneous filling
of two
juxtaposed bags has to be performed.
The guide means can thus be designed according to the above described prior
art
techniques as well as the peripheral areas of the bag items can be designed
according
to the prior art techniques. There is only need for modifying the filling
station in a
way so that it e.g. has two filling units that fill the two juxtaposed bag
items
simultaneously.
Carrier chains or similar in the guide means can therefore be moved through a
course
wherein in the filling station they will draw the two outermost bag edges
apart in such
a way that the two juxtaposed bag items are caused to open in order to enable
filling
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of products into the two bag items from above or possibly from the side. The
bag
edges can then be guided together again for the purpose of final closing and
cutting
off of the filled bag items.
At the end of the filling station, the guide means will typically be drawn
apart such
that the cut off bags can be gripped and moved away, or just fall down upon a
conveyor belt.
It is not important how accurately the conveying is effected, whether a
certain tension
arises on the bag web during conveying if carrier chains provided with studs
are used,
as the bag web will be conveyed in full synchronisation with the carrier
chains in a
secure way.
According to an embodiment, the method may be peculiar in that the peripheral
areas
at the outermost opposite bag opening edges of two juxtaposed bag items are
joined
by welding or welded together with the central support region. Hereby is
achieved an
improved guiding of the outermost bag opening edges.
According to a further embodiment, the method may be peculiar in that the
peripheral
areas at the outermost opposite bag opening edges of two juxtaposed bag items
are
free peripheral areas. This simplifies the bag making itself, though the free
peripheral
areas put greater demands on guidance during conveying of the bag web through
the
apparatus.
According to an embodiment, the apparatus may be peculiar in that the support
rail
includes an endless band, belt or similar for supporting the bag web. The
bands or
belts may thereby contribute to the conveying of the bag web. However, usually
it is
preferred to use a smooth guide rail on which the bag web slides.
According to a further embodiment, the apparatus may be peculiar in that the
filling
station includes a first and a second filling unit, or alternatively includes
a
displaceable filling unit for filling the two juxtaposed bag items. The choice
of filling
unit depends on whether it is the same articles that are filled into both
bags, or
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alternatively whether the advantage achieved by the invention by the option of
filling
different articles into two bag items conveyed in parallel is utilised.
According to a further embodiment, the apparatus may be peculiar in that the
guide
means include conveyor chains with projecting parts projecting freely from the
conveyor chains and which can engage perforations or holes in respective
peripheral
areas, a guide channel that can engage a bead in respective peripheral areas,
guide
rails that can engage a channel in respective peripheral areas, or squeezed
chains or
belts that can engage respective peripheral areas by friction. As mentioned,
by the
invention the options known from the prior art described in the introduction
can be
applied.
According to an embodiment, the bag web may be peculiar in that the peripheral
areas
at the outermost opposite bag opening edges of two juxtaposed bag items are
joined
by welding or welded together with the central support region. Hereby is
achieved a
better guiding of the outermost peripheral areas by conveying through the
apparatus.
According to a further embodiment, the bag web may be peculiar in that the
peripheral
areas at the outermost opposite bag opening edges of two juxtaposed bag items
are
free peripheral areas. This simplifies the bag production.
According to a further embodiment, the bag web may be peculiar in that the bag
web
is formed of a film web which is folded about folding lines in longitudinal
direction of
the bag web, the folding lines disposed with a spacing largely corresponding
to one
fourth of the width of the film web from each side edge of the film web for
forming
the two juxtaposed bag items. The two juxtaposed bag items can thus
advantageously
be made from one film web without any need of combining several film webs.
According to a further embodiment, the bag web may be peculiar in that the
peripheral
areas of the bag web at the outermost opposite bag opening edges of two
juxtaposed
bag items are each provided with a series of perforations for the guide means
in an
apparatus according to the invention. Secure and firm gripping of the
peripheral areas
is hereby achieved.
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According to a further embodiment, the bag web may be peculiar in that the
peripheral
areas of the bag web at the outermost opposite bag opening edges of two
juxtaposed
bag items are each provided with a longitudinal bead for engaging the guide
means in
an apparatus according to the invention. The guide means will include a
channel or a
chain which by friction can grip around the bead.
According to a further embodiment, the bag web may be peculiar in that the
peripheral
areas of the bag web at the outermost opposite bag opening edges of two
juxtaposed
bag items are each provided with a longitudinal channel for engaging the guide
means
in an apparatus according to the invention. The guide means will include guide
rails
that can be received in the channels and thereby provide secure guiding of the
peripheral areas.
When performing the invention, the constructional details of bag web and
apparatus
known from the two European patents EP 1 087 890 and EP 1 451 069 can
therefore
be applied. Thus no detailed explanation thereof is given.
Also, only bag webs with two juxtaposed bags have been mentioned. However,
within
the scope of the invention it will be possible to increase the number of
juxtaposed
bags such that even three or four bags are juxtaposed in transverse direction
and
moved through a filling apparatus.
Description of the Drawing
In the following, the invention will be explained in more detail with
reference to the
enclosed schematic drawing where the channel essential for the invention in
the
central support region is only seen in Figs. 8-9, and wherein
Fig. 1 shows a perspective view for illustrating a technique known
from EP
1 087 890 with a bag web including a single row of bag items;
Fig. 2 shows a perspective partial view of a bag web with two rows
of
juxtaposed bag items in partly open condition in a bag web
according to the invention;
Fig. 3 shows a partial view from above of the bag web shown in
Fig. 2, but
with the bag items in fully open condition;
Figs. 4A-4F show six different possible bag webs according to the
invention;
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Figs. 5A-5C show sectional views for illustrating three steps of
inserting a bag
web shown in Fig. 4A into a filling apparatus;
Fig. 5D shows a perspective partial view of a bag web in the first
step shown
in Fig. 5A;
Figs. 6A-6C show sectional views for illustrating three steps of inserting
a bag
web shown in Figs. 4B-4F into a filling apparatus;
Fig. 6D shows a perspective partial view of a bag web in the first
step shown
in Fig. 6A, with one welding;
Fig. 6E shows a perspective partial view of a bag web in the first
step shown
in Fig. 6A, with two weldings;
Figs. 7A-7D show sectional views for illustrating four alternative
guide means in
an apparatus according to the invention;
Figs. 8A-8B show two further possible bag webs according to the
invention; and
Figs. 9A-9C show sectional views for illustrating three steps of
inserting a bag
web shown in Figs. 8A and 8B into a filling apparatus.
Detailed Description of Embodiments of the Invention
In the explanation of the Figures, identical or corresponding elements will be
provided
with the same designations in different Figures. Therefore, no explanation of
all
details will be given in connection with each single Figure/embodiment.
Fig. 1 shows prior art and serves to illustrate a principle for designing
peripheral areas
at the outermost opposite bag opening edges and guide means adapted to retain
and
guide the peripheral areas at the opposing bag opening edges.
In Fig. 1 is shown that from a supply roll 2 a film material web 4 can be
unrolled,
consisting of a double film folded around a bottom edge 6 and joined along the
upper
edge by a simple welding 8, without any foldings or thickenings of any kind.
Therefore, it may also be a tubular film. In the web appears a series of slits
10 that
extend from the bottom edge 6 up to a point below the upper edge 8 so that the
web
appears with mutually separate bag items 12, the side edges of which closed by
weldings 14. Right over the top of the slits 10, the double web is cut by
respective
horizontal lines 16 extending shortly out at either side of the associated
slits 10.
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Between the upper edge 8 and the cutting lines 16, the peripheral areas 40 of
the web
are penetrated by a single row of perforations 18.
This previously made web 4, which instead of being rolled up better can appear
in a
5 supply box in zigzag folded shape, is unwound by a filling unit on a
support bar or rail
extending from a fixed support member 22 of the unit and serving as simple
support for the closed upper edge 8 of the web 4.
At a short distance in front of the carrier member 22, the support bar 20 has
an
10 upwardly projecting cutter member 24 which by advancing the web will
continuously
cut the upper edge of the latter, and thereafter is arranged a continuing
carrier system
consisting of opposing parallel chain runs 26 that are made with upright
holding studs
28 for engaging holes 18 in respective top parts of the web that are laid out
at both
sides, and by a pressing roller 30 which after threading the film web in
provides for
15 drawing down the said unfolded upper edge areas of the web 4 towards the
firmly
supported carrier chains 26 for horizontal bearing against the top sides of
the latter,
and thereby under pivoting down of the holes 18 in such a way that the holes
18 are
pivoted down and engage over the chain studs 18. The pressing roller 30 has
turned-in
grooves 32 for enabling free passage of the outer end parts of the chain studs
28, and
20 in these grooves there are embedded transversely positioned studs (not
shown) which
like a cogwheel can interact with the chain studs 28 for automatic synchronous
driving
of the pressing roller 30.
The opposing upper edge parts of the web 4 will then be securely anchored to
the
carrier studs 28, and the carrier chains may then be guided through a desired
course
for successive opening of the bag items as indicated by 34, whereby they can
be filled
by a filling apparatus 36 disposed above the open bag item and for closing the
items
after filling thereof. The filling apparatus 36 is provided with a filling
unit in the form
of a filling nozzle 38. It is considered unnecessary to indicate this in more
detail.
However, it is to be noted that the studs 28 are provided in the neutral lines
of the
chains such that the bag item web is not subjected to tensioning or slacking
in
passages with changes of direction.
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The filled bags are released from the rest of the web, which is rolled up as
excess, by
weld closing of the bag items immediately under the top of the slits 10 and
possible
subsequent cutting off.
It is to be mentioned that on the fixed carrier member 22 there is preferably
provided a
guide body with a double-wing ploughshare shape that actively produces or
initiates
the shown unfolding of the perforated web periphery areas, whereby an improved
security can be achieved with regard to the important function that is the
guiding of
the holes down over the studs 28.
Fig. 2 shows an apparatus according to the invention, wherein a bag web with
two
juxtaposed bag items 12 is used. At the outermost peripheral areas 40, the bag
items
12 are penetrated by perforations 18 that enable fastening to the retainer
studs 28. At
the bag sides which are disposed close to each other, the peripheral areas of
the bag
sides are formed of a central support region 42 extending longitudinally of
the bag
web. The central support region 42 is placed on the support rail 20. According
to the
invention, the support rail 20 is extended compared with the length shown in
Fig. 1.
The support rail 20 will therefore extend along the conveyor path through a
filling
station 44 where the filling apparatus 36 is provided. The filling apparatus
36 has two
juxtaposed filling nozzles 38 for simultaneous filling of the two juxtaposed
bag items
12.
In a situation before the partial view shown in Fig. 2, the film web can be
handled by a
system as described with reference to Fig. 1. In a situation after the partial
view shown
in Fig. 2, the bag web can be closed and cut off in a way analogous to that
explained
in connection with the bag web shown in Fig. 1.
Fig. 3 shows a view corresponding to the view shown in Fig. 2, but seen from
above.
It is seen here how the bag items 12 are moved farther away from each other
such that
they now are completely open. In this situation, the bag items 12 will be
located at the
filling station 44 (not depicted in Fig. 3 for the sake of clarity).
The bag items 12 have side edges that are closed by means of welds 14.
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Figs. 4A-4F show various possible foldings of bag webs according to the
invention.
The provision of a central support region 42 serves to connect two juxtaposed
bag
items 12. The central support region 42 also serves to provide support on the
support
rail 20 when inserting the bag webs into an apparatus according to the
invention.
In Fig. 4A is seen that the two outermost opposite peripheral areas 40 are
provided as
free edge areas that are not attached to each other or to the support region
42.
Fig. 4B shows a situation where the peripheral areas 40 are fastened to the
central
support region 42 by means of welds 46.
Fig. 4C shows how the two opposing peripheral areas 40 are welded together by
one
welding 48. This single welding 48 can optionally be made with or without
connection
to the central support region 42.
Fig. 4D shows how the two weldings 46 are provided as individual weldings.
Fig. 4E shows an alternative where only one welding 46' is provided, which
simultaneously welds the two outermost opposite peripheral parts 40 to the
central
support region 42.
Fig. 4F illustrates how a welding 48 is used for welding the free peripheral
regions 40
together without connection to the central support region 42.
Figs. 5A-5C show how a bag web is moved and opened when inserted in a packing
apparatus. Fig. 5A shows the two bag webs without opening them and resting on
the
support during their advancing for engagement with the guide means.
Fig. 5B shows the situation where the bag web is brought to engage the guide
means
in the form of the studs 28 engaging perforations on the outermost opposite
peripheral
areas 40.
Fig. 5C shows how the guide means has moved the outermost opposite bag opening
edges from each other such that the bag items 12 are open for filling.
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Fig. 5D shows a perspective view corresponding to Fig. 5A for illustrating how
the
bag web with the two juxtaposed bag items 12 is suspended and resting on the
support
rail 20 via the central support region 42.
Figs. 6A-6E are figures that correspond to Figs. 5A-5D. The differences are
that the
outermost opposite peripheral areas are not free, but welded together in a way
as
explained with reference to Figs. 4B-4F. By this design, the weldings 46 and
18,
respectively, will provide guide channels 50 in which supplementary guide
rails 52 are
disposed extending in parallel with the guide rail 20. This provides good
guidance
when conveying the bag web to the filling apparatus. A cutting up is effected
at the
filling apparatus as explained in connection with Fig. 1 such that the
channels 50 are
opened, whereby the outermost peripheral areas 40 can engage the guide means
in the
form of the studs 28.
Figs. 7A-7D show alternative embodiments of the guide means.
Fig. 7A shows a design where the outer peripheral areas 40 are provided with a
bead
54 guided in a channel 56, which is provided fixed on the filling apparatus
and serves
to retain and guide the peripheral areas at the outermost opposite bag opening
edges
through the filling station.
Fig. 7B illustrates that the outer peripheral areas 40 are provided with a
channel 58.
The channel 58 retains and guides the peripheral areas 40 along the conveyor
path
through the filling station.
Fig. 7C shows how the outer peripheral areas 40 are brought to engage gripping
chains 62. The gripping chains 62 can retain and guide the peripheral areas by
squeezing action along the conveyor path through the filling station. These
guide
means 64 can e.g. include cords or the like that may retain and guide the
peripheral
areas 40.
Figs. 8A-8B show two further foldings of bag webs according to the invention.
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In the central support region 42 connecting the two juxtaposed bag items 12,
there is
here provided a closed channel 65 serving as support on the support rail 20 at
the
insertion of the bag webs in an apparatus according to the invention.
In Fig. 8A is seen that the closed channel 65 is formed by welding a separate
film strip
66, which by two weldings 67 is welded on the film web 4 that is used for
making the
bag items 12.
Fig. 8B shows an embodiment where the closed channel 65 is formed. The film
web 4
is provided with a fold 68 forming the channel 65, which is closed by a
welding 69.
Figs. 8A and 8B show closed channels as the welds 67 and 69 are through-going
welds running throughout the length of the film web 4. However, alternatively
spot
weldings may be applied such that the channel appears as a closed channel.
Figs. 9A-9C are figures that correspond to Figs. 6A-6D. The difference in this
embodiment is that the central support region 42, which is placed on the
support rail
20, in this situation is formed as a closed channel 65. The risk of the film
web being
drawn askew by uneven filling of two juxtaposed bags 12 is hereby avoided.
The guide rail mentioned by the various embodiments may consist of a smooth
rail on
which the central support region slides. The guide rail may alternatively
comprise
belts, chains or similar provided with an endless run in such a way as to
contribute to
conveying the bag web along the conveyor path into and through the filling
station.
