Title: Filter bag for containing a substance for infusion with the gathered thread attached to the pick up tag and the method for producing the bag
Abstract: A filter bag for containing a substance for infusion in a liquid comprises: a containment chamber with compartments for doses of the substance, sealed by top and bottom joins; a tag for picking up the bag; and a section of thread, wound around the outside of the containment chamber and extending along an outline of the chamber, one end of the thread being connected to the pick-up tag and the other to the top of the containment chamber. The section of thread is longer than the outline of the containment chamber to which it is attached. The excess length of the section of thread relative to the outline of the chamber is gathered on the outside of the containment chamber for the substance for infusion and is attached to the pick-up tag. A method for production of the filter bag is also part of the invention.
Patent Number: 7,021,025 Issued on 04/04/2006 to Romagnoli
| Inventors:
|
Romagnoli; Andrea (Castenaso, IT)
|
| Assignee:
|
Tecnomeccanica S.r.l. (Bologna, IT)
|
| Appl. No.:
|
780958 |
| Filed:
|
February 18, 2004 |
Foreign Application Priority Data
| Jan 11, 2002[IT] | BO2002A0013 |
| Current U.S. Class: |
53/413; 53/450; 53/134.2 |
| Current Intern'l Class: |
B65B 61/14 (20060101); B65B 9/06 (20060101) |
| Field of Search: |
53/413,450,134.2
156/176,297
426/82,83
493/375
|
References Cited [Referenced By]
U.S. Patent Documents
| 2468464 | Apr., 1949 | Salfisberg.
| |
| 2490057 | Dec., 1949 | Irmscher.
| |
| 2852389 | Sep., 1958 | Johnson.
| |
| 2869718 | Jan., 1959 | Whelan.
| |
| 4828851 | May., 1989 | Romagnoli.
| |
| 5399224 | Mar., 1995 | Vernon et al.
| |
| 5580408 | Dec., 1996 | Vernon et al.
| |
| 5871789 | Feb., 1999 | Romagnoli.
| |
| 6389781 | May., 2002 | Ghirlandi.
| |
| Foreign Patent Documents |
| 2850604 | Jul., 1979 | DE.
| |
| 0 806 352 | Nov., 1997 | EP.
| |
| 1002741 | Jun., 1998 | EP.
| |
| 1016599 | Dec., 1998 | EP.
| |
| 1 016 599 | Jul., 2000 | EP.
| |
| 1 223 110 | Jul., 2002 | EP.
| |
| 962 038 | Jun., 1964 | GB.
| |
| 2 052 428 | Jan., 1981 | GB.
| |
| 2052428 | Jan., 1981 | GB.
| |
| 2 333 764 | Aug., 1999 | GB.
| |
| WO99/21762 | May., 1999 | WO.
| |
Other References
European Search Report dated Decembver 29, 2003, corresponding to European Application
No. EP 02 42 5781.
|
Primary Examiner: Sipos; John
Attorney, Agent or Firm: Fay, Sharpe, Fagan, Minnich & McKee, LLP
Parent Case Text
This application is a division of 10/341,570 filed Jan. 13, 2003.
Claims
What is claimed is:
1. A method for producing a filter bag for containing a substance for infusion
in a liquid, said method comprising:
feeding in a predetermined feed direction and parallel with one another: a filter
paper web, a cotton thread positioned longitudinally to and opposite the filter
paper web and a succession of tags, the tags being placed along the web at predetermined intervals;
forming on the thread a succession of first winding loops, separated by an interval
corresponding to the tag interval;
connecting the first winding loops of thread to the pick-up tags, and connecting
the pick-up tags to the paper web;
folding the filter paper web over itself in a direction away from the thread
and tag so that longitudinal edges of the filter paper web which were initially
opposite one another are overlapping, gradually forming a filter paper tube in
which the thread and tag are on the outside of said tube;
depositing a succession of doses of the substance for infusion on the web, before
the tube is definitively formed;
connecting the longitudinal edges of the tube to one another;
making pairs of transverse connections on the tube, upstream and downstream of
each tag, designed to delimit a succession of sealed containment chambers containing
at least one dose of the substance for infusion;
securing the sections of thread between the transverse connections to the tube;
cutting the filter paper web at a predetermined distance from one of said pickup
tags to form a slit; and,
forcing the thread through the slit to form a second loop projecting from the
filter paper web on a side opposite that in contact with the thread.
2. The method according to claim 1, in which the filter paper web has a layer
of heat-activated adhesive material, wherein the connection of the longitudinal
edges of the tube is made by heat-activation of the layer of adhesive material
on the web.
3. The method according to claim 1, in which the filter paper web has a layer
of heat-activated adhesive material, wherein the pairs of transverse connections
are created by heat-activation of the layer of adhesive material on the web.
4. The method according to claim 1, in which the filter paper web has a layer
of heat-activated adhesive material, wherein the step of securing the sections
of thread between the connections to the tube is done by heat-activation of the
layer of adhesive material.
5. The method according to claim 1, in which the pick-up tag comprises two flaps
which can be folded over one another, wherein the first loop is attached to the
pick-up tag at one flap of the tag, the method comprising a folding step in which
the second flap of the tag is placed so that it overlaps the first loop and is
connected to the first flap of the tag.
6. The method according to claim 5, in which the pick-up tag has a layer of heat-activated
adhesive material, wherein the flaps are connected to one another by heat-activation
of the adhesive material.
7. The method according to claim 5, further comprising a step in which the tag
is creased to form a fold line for facilitated folding of one flap relative to
the other.
8. The method according to claim 2, wherein the step of attaching the pick-up
tag to the filter paper tube is performed by heat-activation of the layer of adhesive material.
9. The method according to claim 1, wherein during formation of the tube the
second loop is housed in a concave section of the web.
10. The method according to claim 1, further comprising a sealing step in which
the second loop and the filter paper web are attached to one another.
11. The method according to claim 10, wherein the step of sealing the second
loop to the filter paper web takes place before the tag is sealed to the filter
paper web.
12. The method according to claim 2, in which the containment chamber is divided
into two adjacent compartments, further comprising a step of folding the compartments
so that they overlap one another and the thread is wound around the overall outline
of the containment chamber so that the tag and first loop connected to it are located
on an outer face of the overall containment chamber; and a step of uniting the
top joins of the tubular compartments to form a single top of the filter bag containment chamber.
13. The method according to claim 12, wherein the step of uniting the top joins
of the containment chamber is performed by sealing by heat-activation of the layer
of adhesive material on the filter paper.
14. The method according to claim 1, further comprising a cutting step in which
the corners of the tops of the containment chambers are removed from the bag.
Description
BACKGROUND OF THE INVENTION
The present invention relates to the automatic packaging of a substance for infusion,
such as tea, chamomile, or similar herbal products, in paper filter bags, designed
to be immersed in a liquid to prepare the infusion. In particular, the present
invention relates to a filter bag with a special structure and the method for its production.
Recent market research has highlighted renewed interest in filter paper bags
with a containment chamber which has two compartments, also known as two-lobed
filter bags, made by heat-sealing. The filter bag is obtained by folding the filter
paper then sealing the folds obtained in this way, using heat to activate a layer
of glue spread on the paper web during one of the production steps.
However, filter bags made of heat-sealable filter paper using the conventional
method are heavier than bags of the same size and shape in which the chambers which
hold the doses of product are obtained by folding alone.
Since the cost of the paper is proportional to its weight, the greater weight
of the bags made of heat-sealable filter paper means that, all other conditions
being equal, they are more expensive than those made using folding alone. Since
they are products with a low absolute weight, even a weight which is just a few
grams higher has a significant percentage effect on the overall cost of the bag.
To make bags made of heat-sealed paper economically competitive with bags made
using folding alone, it is common practice to give the bags made of heat-sealed
paper smaller overall dimensions than those of the corresponding bags made of folded paper.
When the bag made of heat-sealed paper is made with the pick-up tag connecting
thread wound around the bag and precisely as long as the outline of the bag, the
latter's reduced dimensions mean that the working length of the thread available
is shorter.
If the infusion is prepared in certain types of tea-pots or in particularly tall
cups or glasses, said thread length may be insufficient to prevent the tag from
accidentally slipping over the edge of the infusion container during infusion and
falling into the infusion liquid, with obvious consequences in terms of hygiene
and/or pick-up tag recovery.
Moreover, bags made of heat-sealed paper using the known method, at the
production step also involve the use of a blob of adhesive—normally Mylar®,
which, attached to the thread and the bag, allows them to be held together in a
compact structure, preventing the tag from dangling freely from the bag.
The material used for the blob of adhesive has its own cost, which disadvantageously
increases the overall cost of the filter bag. Other costs are also related to the
complex construction of the packaging machines which require a purpose-designed
unit for the adhesive for the bag.
SUMMARY OF THE INVENTION
The main aim of the present invention is to overcome the aforementioned disadvantages
by providing a bag made of heat-sealable paper which is designed in such a way
that it has a section of connecting thread whose length is not related to the length
of the outline of the filter bag.
Another aim of the present invention is to eliminate the need for Mylar,
making the filter bag even more economical and the equipment used to make it less
complex and expensive.
According to the invention, these and other aims are fulfilled by a filter
bag for containing a substance for infusion in a liquid comprising a containment
chamber, with at least one compartment for holding a dose of the substance which
is sealed by top and bottom joins; a tag for picking up the bag; and a section
of thread, wound around the outside of the containment chamber and extending along
an outline, one end of the thread being connected to the pick-up tag and the other
end connected to the top of the containment chamber, and wherein the section of
thread is longer than the outline of the containment chamber to which it is attached,
the excess length of the section of thread relative to said outline being gathered
on the outside of the containment chamber for the substance for infusion. The present
invention also refers to a method for producing the bag.
BRIEF DESCRIPTION OF THE DRAWINGS
The technical features of the present invention, in accordance with the above-mentioned
aims, are set out in the claims herein and the advantages more clearly illustrated
in the detailed description which follows, with reference to the accompanying drawings,
which illustrate a preferred embodiment of the invention without limiting the scope
of the inventive concept, and in which:
FIG. 1 is an enlarged side assembly view of a bag made in accordance with the
present invention;
FIG. 2 is a front view of the bag illustrated in. FIG. 1;
FIG. 3 is a detail of the bag illustrated in FIG. 1 seen from the side opposite
that in FIG. 2;
FIGS. 4 through 13 are schematic views of the succession of steps embodying
the method for production of the bag illustrated in FIGS. 1-3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the accompanying drawings, FIG. 1 illustrates as a whole a
filter bag
1 for containing a substance for infusion in a liquid, such as
tea, chamomile or other herbal products, which basically comprises a chamber
2
for containing the substance and a tag
6 for manually picking up and holding
the containment chamber
2 during infusion, connected to one another by a
section of thread
7.
The containment chamber
2 has two separate compartments
3 for doses
of the substance, which are connected to one another at a top join
4 and
a bottom join
5.
The compartments
3 are set opposite one another, overlap and are connected
by a folded base
14 which is "V"-shaped, with the narrow base of the V pointing
upwards towards the inside of the containment chamber
2.
The section of thread
7 is wrapped around the outside of the containment
chamber
2. It extends along an outline of the chamber and one end of the
thread is connected to the pick-up tag
6, whilst the other end is connected
to the top
15 of the containment chamber
2.
The section of thread
7 is longer than the outer outline of the containment
chamber
2 to which it is attached. The excess length
8 of thread
7 relative to the length of the outline is looser than the rest of the section
of thread
7 which, in contrast, is pulled taut along the outline of the
containment chamber
2 and is gathered, on the outside of the containment
chamber
2 for the substance for infusion, in the form of one or more first
winding loops
10 attached to the pick-up tag
6.
This is clearly visible in FIGS. 1 and 2 which illustrate in particular that
the pick-up tag
6 includes two flaps
9a, b, folded over one
another by rotation about a shared edge
35, parallel with the section of
thread
7 wound around the outline of the bag
1. The excess length
8 of the section of thread
7 is held between these flaps
9a,
b.
The pick-up tag
6 preferably has a layer of adhesive material on the faces
of the flaps
9a and
b facing the excess length
8 of
thread, which can be activated by suitable heat, so that the flaps
9a,
b of the tag
6 stick together and hold the excess length
8 of
the section of thread
7 there gathered tightly and in an orderly fashion.
This hold, sufficient to prevent any change in the state of the package during
handling, is removable and can be overcome by applying a small amount of pulling
force to the section of thread
7 outside the tag
6 to unwind the
first loop(s)
10 and allow the consequent extraction of the excess length
8 of thread from the bag
1 pick-up tag
6.
The fixing to the tag
6 of the free end
36a of the section
of thread
7 adjacent to the excess length
8 is achieved by passing
it through and sealing flaps
37 of the tag
6 transversally to the
section of thread
7. The flaps
37 are connected internally by a sealing
bead
38 and the free end
36a of the section of thread projects
from them towards the top
15 of the bag
1.
FIG. 2 also shows how the pick-up tag
6 is connected to the side wall
16 of the containment chamber
2 by a seal—labeled
13—also
obtained using a layer of heat-activated adhesive on one of the faces of the flap
9a of the tag
6 flaps
9a and
b, that
is, the one facing the containment chamber
2.
The section of thread
7 also comprises a second loop
11, housed
in the compartment
3 of the containment chamber
2 opposite and separate
from the compartment
3 contiguous with the tag
6. This second loop
11 has diverging ends
12a,
12b which project
from the compartment
3. One end
12a goes towards the top
15,
the other
12b towards the bottom
14 of the containment chamber
2. The end
12a which goes towards the top
15 is gripped
and secured between opposite faces of the compartment
3 which are sealed
together to form the top join
4—by heat activation of a layer of adhesive
on the filter paper of which the walls of the compartment are made. The end
12b
which goes towards the bottom
14 of the chamber projects through the
side wall
16 opposite that on which the tag
6 is fixed, at a convenient
slit
22 in the side wall
16.
Since, as illustrated in FIG. 3, the ends
12a,
12b
of the second loop
11 are moved relative to one another transversally
to the section of thread
7, pulling the section of thread
7 connected
to the ends
12a and
12b wrinkles the top
15
of the containment chamber
2, guaranteeing that the section of thread
7
is secured to the top
15.
Therefore, in the filter bag
1 described above, the ends
36a
and
36b of the section of thread
7 are secured to the
top
15 of the containment chamber
2 at the two top joins
4
which also seal the two separate containment chamber
2 compartments
3.
The aforementioned filter bag
1 is used for conventional infusion by manually
picking up the tag
6 with the containment chamber
2 suspended from
it. However, the presence of the excess length
8 of thread gathered between
the pick-up tag
6 flaps
9a and
b allows a change at
the user's discretion in the actual distance between the tag
6 and the top
15 of the bag
1, so that on each occasion the length of the section
of thread
7 can be made compatible with the different sizes of cups or glasses
in which the infusion is prepared. This is all possible without the risk of the
pick-up tag
6 accidentally falling into the infusion liquid.
FIGS. 4 to 13 schematically illustrate the operating sequence consisting of
the succession of steps for production of the filter bag
1 disclosed.
With references to these figures, firstly it must be said that the production
process involves the steps of feeding only three packaging materials along a predetermined
feed direction
30 and parallel with one another in a suitable sequence.
These materials consist of a filter paper web
17 with a layer of heat-activated
adhesive, a cotton thread
31 positioned longitudinally and opposite the
filter paper web
17, and a tag paper web
39, from which a set of
tags
6 is made in succession which are positioned along the filter paper
web
17 at predetermined intervals
32.
FIG. 4 shows how the tag paper web
39 being fed in the feed direction
30 is first creased lengthways along the middle of it in order to create
on the web
39 a line
21 that can facilitate folding of the web
39.
Next, the paper web
39 is cut transversally, to form tags
6 with
two separate coplanar flaps
9a, b, separated from one another by
the fold line
21.
After the tag
6 has been cut and positioned relative to the thread
31,
as illustrated in FIG. 5, the process involves the step of forming on the thread
31 and with the aid of suitable fork means
40, one or more first
winding loops
10 gathered in succession one on top of another and designed
to form a sort of hank of thread
31 positioned in front of one
9a
of the tag
6 open flaps
9a and
b.
In a subsequent step, schematically illustrated on the left of FIG. 6, the flap
b of the tag
6 which is not in contact with the hank of thread
31,
is gradually folded about the fold line
21 and brought into position overlapping
the other tag
6 flap
9a. It is then sealed by heat-activation
of the layer of adhesive material which, after folding, the two faces
9a
and
b of the tag
6 hold opposite one another.
At this point, with reference to the right-hand side of FIG. 6, the filter paper
web
17—which in the figure appears to be on top of the thread
31
with the tags attached—is cut in such a way as to make a slit
22 in
the paper.
The thread
31 is forced to pass through the slit
22—on the
left of FIG.
7—over the filter paper web
17 to form the second
loop
11. During the following step, the loop
11 may be tightly secured
to the filter paper by sealing, thanks to conveniently localized heat re-activation
of the layer of adhesive material on the filter paper.
During the same operation a seal may also be made which attaches the filter
paper to the tag
6 below, including the hank of thread.
Then, as shown on the right-hand side of FIG. 7, the process involves the steps
of winding the filter paper web
17 over itself so that the edges
18
initially opposite one another are overlapping, to gradually form a filter paper
tube
34 with the loop
11 inside its internal concave area. Then,
before the tube
34 is definitively formed, two doses
19 of the substance
for infusion are deposited on the web
17 one after another.
When the edges
18, schematically illustrated on the left and at the center
of FIG. 8, are completely overlapping, the process involves the step of connecting
the longitudinal edges
18 of the tube
34 to one another by sealing,
by heat activation of the layer of adhesive material on the filter paper.
During a subsequent step, illustrated on the right of FIG. 8, the tube
34
is divided into separate compartments
3, each containing a dose
19
of the substance for infusion. The compartments
3 are created by making
pairs of sealed transversal connections
20, respectively upstream and downstream
of the tag
6. More specifically, these connections form the top join
4
and the bottom join
5 which seal the compartments
3, also securing
the thread
31 to the filter bag
1 containment chamber
2.
During a subsequent step in the process, schematically illustrated in FIG.
9, sections comprising two adjacent compartments
3 are cut and separated
from the tube
34.
During the step schematically illustrated in FIG. 10, the two adjacent compartments
3 are folded over one another and at the same time an inverted "V" shape
fold is made in the base
14 of the containment chamber
2.
Following sealing of the top, illustrated in FIG.
12—where
the compartments
3 are attached to one another to form a single-piece top
15 of the containment chamber
2, in a subsequent step illustrated
in FIG. 13 the corners
23 of the top
15 of the filter bag
1
are cut off.
The invention described can be subject to modifications and variations without
thereby departing from the scope of the inventive concept. Moreover, all the details
of the invention may be substituted by technically equivalent elements.
*
