US20090074333A1

US20090074333A1 - Packaging Bag with Tearing Aid

Info

Publication number: US20090074333A1
Application number: US12/208,472
Authority: US
Inventors: Martin Griebel; Wolfgang Wittenbecher
Original assignee: Jenoptik Automatisierungstechnik GmbH
Current assignee: Jenoptik Automatisierungstechnik GmbH
Priority date: 2007-09-18
Filing date: 2008-09-11
Publication date: 2009-03-19
Also published as: CN101391670A; DE102007044829B4; DE102007044829A1

Abstract

The invention relates to a packaging bag with a tearing aid, with which it is reliably provided that the packaging bag is opened in a defined way by manual tearing by the user, so that no packaging contents are lost. The packaging bag is essentially made from a front and a back, which are connected to each other in their edge regions with a material fit and which thus forms a joint edge, in which an opening notch is formed, whose center line intersects two weakened lines at an intersection point starting at a distance from the notch tip. These weakened lines each extend across the width of the front and the back. The direction of the weakened line at the intersection point encloses, with the center line, a tear angle greater than 0° and less than 90°.

Description

FIELD OF THE INVENTION

The invention relates to a packaging bag made from a flexible one-layer or multi-layer packaging material, such as, paper, plastic, and/or metal, with a tearing aid that allows defined tearing of the packaging bag.

BACKGROUND OF THE INVENTION

The necessity of defined tearing of a packaging bag, when such a bag is opened by manual tearing without the use of any tool, is especially important if the package contents involve such materials as liquid, bulk material, or a plurality of small parts, so that the packaging contents partially or completely escape as a result of uncontrolled opening of the packaging bag.
The packaging size and the packaging material of packaging bags according to the class are defined as a function of the type and quantity of the package contents and can be very different. These packaging bags can indeed differ in shape, but, in the broadest sense, they always involve a packaging bag with a front and a back, which are connected to each other in their edge region with a material fit. The connection can already exist over a part of the edge region due to a folding of the blank for the packaging bag. The other parts of the edge region are connected to each other by adhesion or fusion over a given edge width (called joint edge below).
Upon vertical positioning or holding of the packaging bag, for which the labeling on the packaging bag contains adequate instruction, a hollow space forms in the upper region of the bag volume free of the packaging contents. In this region, the front and the back can be at least partially brought into contact with each other when they are pressed together. So that no packaging contents are lost as the package is being torn, the tear line that is being formed, starting from the edge region bordering the hollow space, may extend only across the regions of the front and back that border the hollow space. However, without a tearing aid, most materials do not always tear in the desired regions.
Examples for packaging bags according to the invention will be discussed below.
For packaging building materials, such as cement, frequently a two-layer packaging material is used that consists of a plastic film, which faces the interior of the bag and which serves the purpose of merely protecting the packaging contents from moisture, and a very tear-resistant, robust paper layer that faces the exterior of the bag and which reliably withstands both the weight of the packaging contents itself, which, in the case of cement, can exceed 30 kg, and the transport loads. The bag shape here is a typical sack shape defined by an upper edge, a lower edge, and two side edges. The side edges, and often the lower edge, are formed here by means of creases. The upper edge is a joint edge with a typical edge width of ca. 1-4 cm.
Rather than weight, but instead requirements for hygiene and long storage life for the packaging contents are important for packages in the food and beverage industry. Particularly for beverage packages, three-layer packaging materials are used consisting of an outer, printed paper or plastic layer, a metal layer, and an inner plastic layer. Here, the typically rectangular bag shapes are often bonded or fused to each other along all of the edges, i.e., the packages have a peripheral joint edge, with a typical edge width of about 2-8 mm.
The packaging material for such items as individually packaged sweets is often only a single-layer plastic film, which is produced, for example, as a tube and which has a lower and an upper joint edge.
In principle, the packaging material is produced in webs or sheets and finished into individual blanks. The blanks are then folded or preformed, and edges lying one on top of another are fused or bonded to each other so that a packaging bag is formed that is completely closed after being filled.
A joint edge is always produced, so that the packaging materials lying directly one on another are connected to each other across a given edge width. The joint edge can be a peripheral, closed edge or can be interrupted by creases.
Packaging bags that have an I-shaped or V-shaped opening notch in a lateral joint edge are widely known. Then, for opening, the packaging bag can be gripped at the joint edge on both sides of the opening notch and pulled apart. The tear is started in the notch direction and should progress through the packaging material in the notch direction, which, however, does not happen in practice if the tear is not guided in this direction.
From practice, solutions are also known in which weakened lines are formed across the width of the front and/or back of the packaging bag, whereby a tear progression is indeed guided, but there is the difficulty of starting the tear at the beginning of the weakened line.
The introduction of an opening notch and a weakened line, which opens into the end of the opening notch, appears to bring together the advantages of both alternatives currently known from past practice. However, to implement this in industrial mass production is very difficult technically, because the two cannot take place in one process, where the opening notch must be positioned exactly relative to the weakened line.
No solutions have been presented that combine an opening notch in the edge region and a weakened line running across the width of a packaging bag.
The formation of a weakened line can take place, in practice, only before the folding or shaping of the packaging bag. Ideally, it is formed into the material web before it is partitioned into blanks for the packaging bag.
The weakened lines can be a partial material separation, a partial material removal, or also embossing along the line course of the desired weakened line.
A partial material separation can be a deep cut that does not completely separate the material, for example, produced with a knife or a stamp.
A partial material removal can be an incomplete separating groove or a perforation or slit line of partially or completely penetrating perforations or slots, or combinations of these.
The formation of an opening notch, in practice, can only be made after the fusing or adhesion of the edge regions. Here, the depth of the notch may not be greater than the width edge of the formed joint edge. To fulfill the mentioned requirements, this processing step must be controlled as a function of the position of the weakened line. Means must be provided that detect the position of the weakened line, in order to control signals that can be derived from these means as control parameters for the positioning of the packaging bag relative to the processing tool for the opening notch, which would be very complicated.

SUMMARY OF THE INVENTION

The invention is based on the problem of creating a packaging bag with a front and a back connected by a joint edge, in which, for guiding a tear, an opening notch and weakened lines are formed for guided tear progression.
This problem is solved by a packaging bag with the features set forth in claim 1.
Advantageous improvements are described in the subordinate claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of a packaging bag according to the present invention will be described in more detail below in connection with the annexed drawings, in which:

FIG. 1 a shows a first embodiment in top view;

FIG. 1 b shows a material web with the blank for the first embodiment;

FIG. 1 c shows a cutout from FIG. 1 a;

FIG. 2 shows a second embodiment;

FIG. 3 shows a third embodiment;

FIG. 4 shows a fourth embodiment;

FIG. 5 shows a fifth embodiment;

FIG. 6 shows a sixth embodiment;

FIG. 7 shows a seventh embodiment;

FIG. 8 shows a packaging bag with triangular front and back;

FIG. 9 shows a packaging bag with additional base part; and

FIG. 10 shows a packaging bag with different front and back sides.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

As is known from practice, packaging bags according to the invention have a front 1 and a back 2, which are at least partially fused or bonded to each other in their edge regions. The edge regions bonded or fused to each other form joint edges 3 of a predetermined edge width.
In FIG. 1 a, a first embodiment of a packaging bag according to the invention is shown in top plan view onto the front 1. The front 1 and the back 2, lying behind the front, have a rectangular shape and are connected to each other by means of a peripheral joint edge 3.
A blank 4 for this packaging bag, shown in FIG. 1 b, is advantageously cut to length from a web of packaging material and has twice the width of the packaging bag. Through folding along the center line, the front 1 and the back 2 are placed so that one overlaps the other. The crease formed by the fold forms one of the two side edges. Connecting the other side edge and the bottom edge would be sufficient to create a packaging bag that can be filled. To achieve an overall symmetric impression or to be able to adequately grip the packaging bag peripherally, however, as a rule the edge region along the crease is also formed as a joint edge 3.
It is clear to someone skilled in the art that the blank 4 can also be shaped in such a way that the front 1 and the back 2 can overlap by means of the bottom edge or also the upper edge. In the latter variant, filling would then be performed from below.
The shape of the two sides need not necessarily be rectangular or identical. For example, in addition to FIGS. 1 to 7, in which the shape of the packaging bag is rectangular, at least in the tear region, FIG. 8 shows a packaging bag with two identical triangular side surfaces, FIG. 9 shows a packaging bag with two identical trapezoidal side surfaces and a third round surface forming a base. In a packaging bag according to FIG. 10, the front side is trapezoidal, and the back is rectangular. A third surface forming a base creates the equalization for the edges of different lengths of the front and the back.
All of the embodiments for a packaging bag according to the invention have the following in common:
an opening notch 5 is provided in a joint edge 3;
two weakened lines 6 are provided across the width of the packaging bag, more precisely, the front 1 and the back 2, wherein these weakened lines 6 divide the packaging bag into an upper bag part 9 and a lower bag part 10; and
the center line 7 of the opening notch 5 intersects the weakened lines 6 at an intersection point 8 at an angle greater than 0° and less than 90° (referred to herein as tear angle α) outside of the opening notch 5 at a distance “a” from the notch tip.
The combination of an opening notch 5 with weakened lines 6 in the manner described represents a tearing aid and is essential to the invention.
A special advantage of this tearing aid lies in its simple production.
It is technically simple to produce an opening notch 5 and the weakened lines 6 with the given conditions because the introduction of the opening notch 5 need not be oriented exactly to the position of the already given weakened lines 6. In particular, if the opening notch 5 is located in the upper bag part 10, it can deviate considerably from its desired position relative to the weakened line 6, without this having significant effects on the tear behavior. In FIG. 8, examples of permissible position deviations are shown.
By spreading apart the regions bordering the opening notch 5, as known from practice, a tear is introduced by means of the notch tip. The tear propagates from the notch tip in an uncontrolled way in the front 1 and the back 2 of the packaging bag until it meets the weakened lines 6 at an intersection point 8. Strictly speaking, as it leaves the joint edge 3, i.e., at the end of the material connection between the front 1 and the back 2, the spreading tear divides into two tears. Because they spread in an uncontrolled way, they could also meet the weakened lines 6 at different intersection points 8. However, in order not to unnecessarily complicate the description of the invention, only one tear is referred to below, which, starting from the notch tip, meets the weakened lines 6 at an intersection point 8.
From there, the progression of the tear is guided along the weakened lines 6, that is, the packaging bag is separated in a defined way into a lower bag part 9 and an upper bag part 10, apart from a negligibly short path. The separation line defines the opening edge of the lower bag part 9 that is formed. Through a selected guidance of the weakened lines 6, which form the separation line, the opening edge can be advantageously formed for discharging or pouring out the packaging contents.
The weakened lines 6 need not be identical in their line course on the front 1 and on the back 2. Also, the distance “a” and the intersection point 8 need not be identical, relative to the front 1 or the back 2. However, in order not to unnecessarily complicate the description of the invention, a congruent line layout shall be assumed, which has the same spacing “a” and the same intersection point 8 on the front 1 and the back 2. An identical line layout is advantageous for the tear behavior, because both weakened lines 6 should be separated simultaneously under the action of a tear force.
Certain advantageous parameter variations of a packaging bag according to the invention are discussed hereinbelow.
Essentially, the positioning of the opening notch 5, the opening angle, and the depth of the opening notch 5, the line layout of the weakened line 6, and its formation, the tear angle α and the distance “a” can vary.
The opening angle of the opening notch 5 has significance only insofar as the opening notch 5 can be better visually detected with a larger opening angle. For fulfilling its function, the opening notch 5 can also be limited to a narrow slot.
The depth of the opening notch 5 must be selected so that the notch tip still lies completely in the joint edge 3. For an opening notch 5 whose center line 7 meets the edge of the joint edge 3 at a right angle, this means that the depth of the opening notch 5 is smaller than the edge width of the joint edge 3. The opening notch 5, however, is at least deep enough that the packaging material can be separated by a moderate tearing force up to the intersection point 8 with the weakened lines 6.
For the tearing behavior, the tear angle α should be as small as possible. Indeed, the reliability of the tear intersecting the weakened lines 6 increases when the tear angle α is larger, but for a small tear angle α, the component of the tearing force in the direction of the weakened line 6 increases as the tear angle α decreases. Preferably, the tear angle α should therefore be greater than 10° and less than 45°.
The distance “a” should be as small as possible. However, if it is selected too small, then position deviations of the opening notch 5 from its desired position could have the effect that the center line 7 intersects the desired line in the opening notch 5. A tear propagating from the notch tip would then not intersect the weakened lines 6.
The weakened lines 6 can be produced by any known material attenuation that can be realized along a line. In particular, the weakened line 6 can be

- a continuous cut line with a constant or variable depth of cut,
- a line of slits or perforations or combinations of these, which are separated by connecting pieces and penetrate or do not penetrate the material,
- a stamped line, or
- a line along which the packaging material has different material properties.

In FIGS. 1-10, the weakened lines 6 are each shown as dashed lines, which represent all of the mentioned embodiments.
As tools for production, typical tools for material separation, material removal, or material modification can be used.
A laser appears to be especially well suited. The possibilities in the selection of a laser with a wavelength suitable for the corresponding packaging material, the adaptation of the laser parameters to the desired material attenuation, and also the variable controllability of the laser radiation, such as, by means of a robot arm or a scanner, make a laser the tool of choice and a lased weakened line a preferred implementation of a weakened line 6.
The weakened lines 6 divide the packaging bag into a lower bag part 9 and an upper bag part 10. When the packaging bag is completely torn, the upper bag part 10 is separated from the lower bag part 9, and the packaging contents should be located completely in the lower bag part 9.
The line course of the weakened lines 6 is preferably straight, angled, or curved, wherein changes in direction should be as continuous as possible.
In the first embodiment of a packaging bag shown in FIGS. 1 a-1 c, the weakened lines 6 have an angled line layout, and these weakened lines correspond to the three edges of the peripheral line of an isosceles trapezoid. The opening notch 5 is formed in the joint edge 3 bordering a side edge, wherein the center line 7 is at a right angle to the side edge. At the intersection point 8, the direction of the line course of the weakened lines 6 encloses, with the side edge and thus also the center line 7, a tear angle α of greater than 0° and less than 90°, ca. 45° here, for example. The distance “a” is selected so that a tear introduced via the opening notch 5 intersects the weakened lines 6 outside of the joint edge 3. If the distance “a” is selected to be too large, then there is the risk that the progressing tear will spread in an uncontrolled way into the lower bag part 9 and, thus, a defined opening would no longer be possible, even before it intersects the weakened lines 6.
In a second embodiment shown in FIG. 2, the distance “a” is reduced in order to increase the reliability that an introduced tear actually intersects the weakened lines 6 and does not run away from these lines in an uncontrolled way. The intersection point 8 still lies within the joint edge 3. This has the effect that the guidance of the progressing tear still starts within the joint edge 3. Instead of an abrupt change in direction according to FIG. 1 a, the line layout of the weakened line 6 has a continuous change in angle, due to the rounding of the angled line layout.
Like all of the embodiments described below, the third embodiment shown in FIG. 3 differs from the two aforementioned embodiments in that the opening notch 5 is not formed within the lower bag part 9, but instead within the upper bag part 10.
This has the advantage that a tear that progresses from the notch tip of the opening notch 5 intersects each of weakened lines 6 completely independently of the distance a.
In this third embodiment, the lateral edge regions are not formed as a joint edge 3, but instead are delimited exclusively by creases. Here, the packaging bag is closed across its length, as shown, on the back 2. The opening notch 5 is located in the joint edge 3 bordering the upper edge of the packaging bag.
The fourth embodiment, shown in FIG. 4, has a sinusoidal line course of the weakened lines 6. Therefore, the open edge of the lower bag part 9 (bag opening) is constructed in such a way that the valley of the sinusoid forms a spout in the front 1 and the back 2. Because the spouts are not exactly opposite in the periphery of the bag opening, liquid packaging contents will be emptied exclusively through one of the spouts, as long as it is held at the lowest point.
In the fifth embodiment shown in FIG. 5, the line course of the weakened lines 6 is again a sinusoid, which is shifted by a half period relative to that in FIG. 4, so that the weakened lines 6 taper off into a valley at the side edges. Here, the valleys could also be used as spouts, in particular, the one opposite the opening notch 5. The opening notch 5 is here formed again in the joint edge 3, bordering a side edge, and is nevertheless located in the upper bag part 10.
Such a construction appears to be especially advantageous because, by means of the opening notch 5 in the upper bag part 9, it is assured that the tear will intersect the weakened line 6, that the packaging contents can be easily emptied and that the user can tear the packaging bag in the usual way, starting from one side edge.
The advantage of a sinusoidal line layout or another periodic line layout also lies in its simple realizability, such as, by means of a laser scanner.
In FIGS. 6, 7, and 8, embodiments are shown in which the line layout of the weakened lines 6 corresponds to a straight line. So that the weakened lines 6 and the center line 7 of the opening notch 5 nevertheless intersect each other at a tear angle α, the opening notch 5 in the sixth embodiment shown in FIG. 6 is formed at a corner, wherein the joint edge 3 limited here would have a wider construction.
In the seventh embodiment disclosed in FIG. 7, the opening notch 5 would be formed at an angle to the side edge, i.e., the center line 7 is not perpendicular to the side edge.
In the embodiment shown in FIG. 8, as already explained, the front 1 and the back 2 are triangular surfaces, which is why an opening notch 5 formed perpendicular to the side edge intersects a straight weakened line 6 running across the width of the packaging bag at a tear angle α. In such a solution, the tear angle α. equals the vertex angle of the triangle, here 35°. Alternative locations for the opening notch are shown at (5).
The smaller the tear angle α, the more easily the tear can transition into the weakened line 6.
List of reference symbols

- 1 Front
- 2 Back
- 3 Joint edge
- 4 Blank
- 5 Opening notch
- 6 Weakened line
- 7 Center line of the opening notch
- 8 Intersection point
- 9 Lower bag part
- 10 Upper bag part
- α Tear angle
- a Distance

While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. Packaging bag with tearing aid, comprising a front and a back, said front and back being connected to each other at least partially in their edge regions with a material fit thereby defining a joint edge of a given edge width, an opening notch formed in said joint edge, and two weakened lines which extend across the width of the packaging bag defining a tearing region on the front and the back and which divide the packaging bag into an upper bag part and a lower bag part, wherein an extension of a center line of said opening notch intersects said weakened lines at an intersection point at a distance from the tip of said notch outside of said notch forming a tear angle with said weakened lines of greater than 0° and less than 900.

2. Packaging bag according to claim 1, wherein said front and said back have a rectangular form at least in said tearing region, and said opening notch is formed on one of the side edges, and wherein said center line of said opening notch extends perpendicular to a side edge, and wherein the direction of the line layout of said weakened lines at said intersection point encloses an angle greater than 0° and less than 90° with said side edge.

3. Packaging bag according to claim 2, wherein the course of said weakened lines represents an angled straight line.

4. Packaging bag according to claim 2, wherein the course of said weakened lines is a sinusoid.

5. Packaging bag according to claim 1, wherein said front and said back have a rectangular form at least in said tearing region, wherein said opening notch is formed on one of the side edges of said bag, and wherein said center line of said opening notch extends at an angle greater than 0° and less than 90° relative to said side edge, the course of said weakened lines is a straight line.

6. Packaging bag according to claim 1, wherein said front and said back have, at least in said tearing region, the shape of an isosceles triangle, and said opening notch is formed on one of said side edges of said bag, wherein said center line of said opening notch extends perpendicular to a side edge, and the direction of the course of said weakened lines at said intersection point encloses, with said side edge, an angle greater than 0° and less than 90°.

7. Packaging bag according to claim 1, wherein said front and said back have the shape of an isosceles triangle, at least in said tearing region, and said opening notch is formed on one of the side edges of said bag, wherein said center line of said opening notch extends at an angle greater than 0° and less than 90° relative to said side edge, and the course of the weakened lines is a straight line.

8. Packaging bag according to claim 1, wherein said opening notch is in the upper bag part.

9. Packaging bag according to claim 1, wherein said intersection point lies within said joint edge.

10. Packaging bag according to claim 1, wherein said tear angle is greater than 10° and less than 45°.

11. Packaging bag according to claim 1, wherein said weakened line is a lased line.