JPH0752953A - Container with reinforcing rib - Google Patents

Abstract

PURPOSE:To obtain excellent strength in the facing direction of the long sides and diagonal direction of the corners of a container having almost a square cross section without an increase in the number of ribs by a method wherein the rib having a trough-shaped cross section is provided around the body of the container and the bottom of the rib is formed in an arc-shape so that the bottom of the rib becomes deepest in the middle of each long side. CONSTITUTION:A container 1 has a cross section of an inequilateral octagon that is created from a square by cutting off its four corners at an angle of 45 deg.. A rib 3 having a trough-shaped cross section is provided around the middle of a body 2 of the container 1, and the bottom 20 of the rib 3 is formed in an arc-shape that is curved inward so that the bottom 20 is shallow at both ends 11 of each long side 10 and gradually deeper toward the middle 12 of the long side 10. Therefore, the cross section of the rib 3 continuously changes, forming a bridge. As a result, there is not a risk of losing its strength sharply with a remarkable change in the shape of the rib 3, so that an excellent strength can be obtained not only in the facing direction of the long sides 10 of the container 1 but also in the diagonal direction of th corners 16 of the container 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container with reinforcing ribs in which a reinforcing rib is formed on the container.

[0002]

2. Description of the Related Art In recent years, a synthetic resin container has been generally used as a container for soft drinks and so-called PET container has been widely used.

In this PET container, it is relatively easy to make the container thin, but if this is done, the strength of the container is reduced, and therefore ribs are formed on the container to reinforce it.

By the way, although there are various forms of the cross-sectional shape of the container, in addition to a circle and a square, the four corners of a quadrangle are 45
There is a deformed octagon cut out at °. In the case of the deformed octagonal shape as described above, since the strength of the container in the facing direction cannot be sufficiently obtained, a method of providing one concave rib around the body of the container is adopted.

The relationship between the concave rib 3 and strength will be described below. FIGS. 15 to 19 show a first comparative example formed by a conventionally known structure, in which the container 1 is made of PET (polyethylene terephthalate: Young's modulus E = 3).
50 kg / mm ² , Poisson's ratio ν = 0.4, wall thickness 0.3
5 mm uniform, the same below), and the body 2 of this container 1
One rib 3 is formed in the rib 3, the depth d of the rib 3 is 1.5 mm, the angle of the inclined portion from the bottom surface 20 of the rib 3 to the side surface of the body 2 is 45 °, and the bottom surface 20 of the rib 3 is 20 degrees. Width of 4
mm (hereinafter, abbreviated as model M1). 17 is a wire frame diagram.

FIG. 18 shows the container 1 of the first comparative example with the long side 1
The result of pressing with a force of 1 kg in the facing direction of 0 is shown to be about 7.1% (the free length in the X direction is 35 mm, the deformation amount is 2.48 mm, and the deformation ratio is 7.1%). Deformation was observed.

On the other hand, when the container 1 of the first comparative example is pressed by the corner portion 16 in the diagonal direction with a force of 1 kg, as shown in FIG. 19, about 0.37% (the free length in the X direction is 43 mm, its deformation) The amount was 0.158 mm, and the deformation rate was 0.37%).

20 to 23 show that the depth d of the rib 3 of the container 1 of the model M1 of the first comparative example is 4.
This is a second comparative example in which the length is 5 mm (hereinafter abbreviated as model M3). FIG. 22 shows the result of pressing the container 1 of the second comparative example with a force of 1 kg in the facing direction of the long side 10, which is about 0.7.
3% (free length in X direction is 32 mm, its deformation amount is 0.2
32 mm, and the deformation rate was 0.73%).

On the other hand, when the container 1 is pressed by the corner portion 16 in the diagonal direction with a force of 1 kg, it is about 4.2% as shown in FIG.
(Free length in X direction is 40 mm, its deformation amount is 1.66 m
m, and the deformation rate was 4.2%).

FIGS. 24 to 27 show a third comparative example in which the ribs 3 are formed at three places in the container 1 of the model M1 of the first comparative example (hereinafter abbreviated as model M5). FIG. 26 shows the result of pressing the container 1 of the third comparative example with a force of 1 kg in the facing direction of the long side 10, about 2.9%.
(Free length in X direction is 35mm, its deformation amount is 1.03m
m, and the deformation rate was 2.9%). On the other hand, the container 1 of the third comparative example is provided with a diagonal corner 1
When 6 is pressed with a force of 1 kg, as shown in FIG.
73% (free length in the X direction is 43 mm, the amount of deformation is 0.
314 mm, and the deformation rate was 0.73%).

Based on the above experimental results, model M1 and model M5
Table 1 shows the comparison with. And
Case 1 in Table 1 shows an experimental result of strength in the facing direction of the long side 10 of the container 1, and Case 2 shows an experimental result of strength in a diagonal direction of the corner portion 16 of the container 1. It is a thing.

[0012]

[Table 1]

[0013]

[Problems to be Solved by the Invention] From the above experimental results,
It can be seen that when the shallow ribs 3 are formed, the strength of the corner portion 16 of the container 1 in the diagonal direction is high, but the strength of the long side 10 of the container 1 in the facing direction decreases. On the other hand, when the deep ribs 3 are formed, the strength of the long side 10 of the container 1 in the facing direction is good, but the strength of the corner portion 16 of the container 1 in the diagonal direction is low.

When the number of ribs 3 is increased, the strength of the long side 10 of the container 1 in the opposite direction is excellent, but the strength of the corner portion 16 of the container 1 in the opposite direction is decreased, and There is a problem that the shape of the mold becomes complicated and the internal volume of the container 1 decreases.

The present invention has been made in view of the above points, and it is possible to obtain excellent strength in the facing direction of the long side of the container and the diagonal direction of the corners without increasing the number of ribs formed. It is a technical object to provide a container with a reinforcing rib.

[0016]

In order to solve the above technical problems, the present invention has the following constitution. That is, the first aspect of the invention is to provide a container 1 in the shape of a square bottle made of polyethylene terephthalate and having a substantially rectangular cross section.
A rib 3 having a valley cross section is provided around the body 2 around the body 2. The ribs 3 are formed on both sides 11 of the long side 10 of the body 2 and on the bottom surface 20 of the rib 3. Depth d up to about 1 mm
Is formed in the range of about 4.5 mm and each long side 10
The bottom surface 20 of the rib 3 is the shallowest at both side portions 11 of each long side 10 and the deepest at the central portion 12 of each long side 10, and is formed in an inwardly curved arc shape to form a container with a reinforcing rib. did.

In a second aspect of the invention, the container 1 according to the first aspect of the invention has a cross-sectional shape in which corners 16 are formed by cutting out the four corners of a square at 45 ° to provide a container with reinforcing ribs. A third aspect of the invention is a container with a reinforcing rib, which is obtained by bending the bottom surface 20 of the rib 3 of the corner portion 16 of the second aspect of the invention so that the central portion bulges outward.

In the fourth invention to the sixth invention, the arc-shaped radius of curvature R of the bottom surface 20 of the rib 3 provided on the long side 10 of any of the first invention to the third invention is 150 mm. A container with a reinforcing rib was used.

[0019]

The rib 3 is formed on the body 2 of the container 1 having a substantially rectangular cross section, and the bottom surface 20 of the rib 3 is curved inward so that it becomes deepest at the central portion 12 of each long side 10. Since the rib 3 is formed in a circular arc shape, the cross-sectional shape of the rib 3 continuously changes, and the shape exhibits a so-called bridge effect.

Therefore, the shape of the rib 3 is not largely deformed, and excellent strength can be obtained in the facing direction and the diagonal direction.

[0021]

Embodiments of the present invention will be described with reference to FIGS. The container 1 is formed by blow molding a parison made of polyethylene terephthalate into a rectangular bottle shape, and the physical properties and thickness of the material are the same as those described above.

[0022]

[First Embodiment] The cross-sectional shape of the container 1 is a square with four corners.
It is an unequal-sided octagon cut out at 5 °, and the distance between its long sides 10 is 73 mm, and the distance between its diagonal portions 16 is 89 mm.
Has become.

A rib 3 having a valley-shaped cross section is provided around the body 2 of the container 1 along the circumference of the body. The depth of the bottom surface 20 of the rib 3 is at both sides 11 of each long side 10. Is the shallowest, and is gradually deepened toward the central portion 12 of each long side 10, and is formed in an arc shape curved inward. The radius R of the rib 3 on the horizontal plane is 150 mm.
Has become.

The strength test results of the container 1 of the first embodiment having the above-described structure as a model M6 will be described with reference to FIGS. 4 and 5. FIG. 4 shows the result of pressing the container 1 of the first embodiment in the facing direction of the long side 10 with a force of 1 kg.
99% (free length in X direction is 31.5 mm, its deformation amount is 0.312 mm, and deformation rate is 0.99%)
Was observed. On the other hand, when the container 1 is pressed in a diagonal direction of the corner portion 16 with a force of 1 kg, it is about 1.
3% (free length in X direction is 40 mm, its deformation amount is 0.5
36 mm, and the deformation rate was 1.3%).

[0025]

[Second Embodiment] Next, a second embodiment will be described with reference to FIGS. A rib 3 having a valley-shaped cross section is provided around the trunk of the body 1 of the container 1 along the circumference of the trunk.
The bottom surface 20 has a depth d that is the shallowest at both side portions 11 of each long side 10 and is gradually deepened toward the central portion 12 of each long side 10 so as to be curved inwardly. ing.

The cross section of the rib 3 is such that the radius R of the bottom surface 20 of the rib 3 provided at the corner 16 of the quadrangle is curved to 12.5 mm, and the bottom surface 20 of the rib 3 provided at each long side 10 is centered. The portion 12 has an arcuate shape that is curved inward so as to be the deepest. The radius R of the rib 3 on the horizontal plane is 150 mm. .

The container 1 having the above-mentioned structure is used as a model M7, and the strength test result will be described with reference to FIGS. 8 and 9.
FIG. 8 shows the result of pressing this container 1 in the facing direction of the long side 10 with a force of 1 kg, which is about 0.74% (the free length in the X direction is 0.233 mm, and the deformation rate is 0.74%. Was)
Was observed.

On the other hand, the corner portion 16 of this container 1 is applied with a force of 1 kg.
When it is pressed in the diagonal direction of about 2.2% as shown in FIG.
(Free length in the X direction is 41 mm, the amount of deformation is 0.909.
mm, and the deformation rate was 2.2%).

The above results are summarized in Table 2. Then, Case 1 and Case 2 are similar to those in Table 1.

[0030]

[Table 2]

[0031]

[Third Embodiment] Next, a third embodiment will be described with reference to FIGS.
It will be described based on. In this embodiment, horizontal ribs 4 having a corrugated cross section are formed in multiple stages on a body 2 of a container 1, and a rib 3 having a valley-shaped cross section is provided around the body around the center of the body 2. It is a thing. The depth of the rib 3 is 1 on each long side.
It becomes the shallowest on both sides 11 of 0, and the central part 1 of each long side 10
It is formed in an arc shape that curves inward so that it becomes deeper as it reaches 2.

That is, the AA 'cross section in FIG.
Looking at the BB ′ cross section and the CC ′ cross section, as shown in FIG. 12, the depth d of the bottom surface 20 of the rib 3 is 2.5 mm at the shallowest part d1, 3.2 mm at d2, and the deepest part (center). Part) is 4
mm.

Although the surface width L of the rib 3 is the same,
The width L'1 of the bottom surface 20 is 6 mm, L'2 is 5 mm, and L'3
Is 4 mm. In this way, the rib 3 has a deep valley at the center when viewed in the plan view shown in FIG.

As a result of the strength test of the container having the above structure,
The following results were obtained. First, when the container 1 was compressed with a strength of 1 kg in the facing direction of the long side 10, as shown in FIG. 13, about 2% on the pressing surface side (the free length in the X direction is 33 mm, the deformation amount is 0.648 mm). The deformation rate was 2%) and the side surface was approximately 1.9% (the free length in the Y direction was 33%).
mm, the deformation amount was 0.621 mm, and the deformation ratio was 1.9%).

Subsequently, the container 1 is set to 1 at the diagonal corners 16.
When compressed at a strength of kg, as shown in FIG. 14, about 1.1% in the diagonal direction in the stress direction (the free length in the X direction is 4
2 mm, the amount of deformation was 0.497 mm, and the deformation rate was 1.1%.) Deformed and expanded about 1.1% even in the diagonal direction orthogonal to the stress direction (free length in Y direction was 42 m.
m, the deformation amount is 0.468 mm, and the deformation rate is 1.
It became 1%).

In this way, the strength of the long side 10 in the facing direction and the strength of the corner portion 16 in the diagonal direction can both be achieved, and the buckling does not occur due to an external force. This is because the cross-sectional shape of the rib 3, in particular, the depth of the bottom surface 20 is formed inwardly so as to be the deepest in the central portion 12 of each long side 10, and is formed in a curved arc shape so as to be continuously changed. Therefore, it is considered that the bridge is structurally configured to exert a resistance force against an external force. Further, in the embodiment, the width L'of the bottom surface 20 is also narrowed toward the center, and it is considered that the synergistic effect of these increases the strength further.

Incidentally, the minimum depth and the maximum depth of the rib 3 are not limited to the above-mentioned examples, and it is needless to say that they can be appropriately set within the range of about 1 mm to about 4.5 mm. As described above, the strength in the facing direction and the strength in the diagonal direction can be made compatible in any of the embodiments. It is considered that this is because the cross-sectional shape of the rib 3, in particular, the depth is continuously changed, so as to structurally form a bridge and exert a drag force against an external force.

[0038]

According to the present invention, a rib 3 having a valley-shaped cross section is provided around a body 2 of a container 1 having a substantially rectangular cross section, and the bottom surface of the rib 3 on each long side 10 is provided. 20 is
Since it is formed in an arcuate shape that curves inward so that it becomes deepest at the central portion 12 of each long side 10, the cross-sectional shape of the rib 3 changes continuously, and that shape constitutes a bridge.

For this reason, there is no fear that the shape of the rib 3 will be greatly deformed and the strength will be sharply reduced, and it is particularly excellent not only in the facing direction of the long side 10 of the container 1 but also in the diagonal direction of the corner portion 16 of the container 1. Strength is obtained. In addition, the shape of the mold is simpler than that of the rib 3 having a large number of stages, and it is possible to minimize the decrease in the volume of the container.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the first embodiment of the present invention.

FIG. 3 is a wire frame diagram of the first embodiment of the present invention.

FIG. 4 is a graph showing the results of a strength test in the facing direction of the first embodiment of the present invention.

FIG. 5 is a graph showing the results of a diagonal strength test of the first embodiment of the present invention.

FIG. 6 is a cross-sectional view of the second embodiment of the present invention.

FIG. 7 is a wire frame diagram of the second embodiment of the present invention.

FIG. 8 is a graph showing the results of the strength test in the facing direction of the second embodiment of the present invention.

FIG. 9 is a graph showing the results of a diagonal strength experiment of the second embodiment of the present invention.

FIG. 10 is a side view of the third embodiment of the present invention.

FIG. 11 is a plan view of a third embodiment of the present invention.

12 is a sectional view of a third embodiment of the present invention, FIG.
0 is a sectional view taken along the line AA ′, FIG. 10B is a sectional view taken along the line BB ′ of FIG. 10, and FIG. 10C is a sectional view taken along the line CC ′ of FIG. 10.

FIG. 13 is a graph showing the results of the strength test in the facing direction of the third embodiment of the present invention.

FIG. 14 is a graph showing the results of a diagonal strength experiment of the third embodiment of the present invention.

FIG. 15 is a partial side view of the first comparative example of the present invention.

FIG. 16 is a cross-sectional view of a first comparative example of the present invention.

FIG. 17 is a wire frame diagram of a first comparative example of the present invention.

FIG. 18 is a graph showing the results of the strength test in the facing direction of the model M1 of the first comparative example of the present invention.

FIG. 19 is a graph showing the results of a diagonal strength experiment of the model M1 of the first comparative example of the present invention.

FIG. 20 is a cross-sectional view of a model M3 of the second comparative example of the present invention.

FIG. 21 is a wire frame diagram of a second comparative example of the present invention.

FIG. 22 is a graph showing the results of the strength test in the facing direction of the model M3 of the second comparative example of the present invention.

FIG. 23 is a graph showing the result of a diagonal strength experiment of the model M3 of the second comparative example of the present invention.

FIG. 24 is a partial side view of a model M5 of a third comparative example of the present invention.

FIG. 25 is a wire frame diagram of a third comparative example of the present invention.

FIG. 26 is a graph showing the results of the strength test in the facing direction of the model M5 of the third comparative example of the present invention.

FIG. 27 is a graph showing the result of a diagonal strength test of the model M5 of the third comparative example of the present invention.

[Explanation of symbols]

 1 Container 2 Body 3 Rib 10 Long Side 11 Both Sides 12 Central Part 16 Corner 20 Bottom Bottom d Depth to Bottom of Rib

Claims (4)

[Claims] 1. A rectangular bottle-shaped container 1 made of polyethylene terephthalate having a substantially rectangular cross section is provided, and a rib 3 having a valley-shaped cross section is provided on a body 2 of the container 1 along the circumference of the body 2. The ribs 3 are provided on both sides 11 of the long side 10 of the body portion 2, and the depth d to the bottom surface 20 of the rib 3 is about 1 mm.
While being formed in a range of about 4.5 mm, the bottom surface 20 of the rib 3 of each long side 10 becomes the shallowest at both side portions 11 of each long side 10, and becomes the deepest at the central portion 12 of each long side 10, A container with a reinforcing rib formed in the shape of an arc curved inward. 2. The container 1 has a cross-sectional shape in which the four corners of a square are four.
The shape having a corner 16 cut out at 5 ° is provided.
Container with reinforcing rib as described. 3. The container with reinforcing ribs according to claim 2, wherein the bottom surface 20 of the rib 3 of the corner portion 16 is curved so that the central portion bulges outward. 4. The container with reinforcing ribs according to claim 1, wherein the bottom surface 20 of the rib 3 provided on the long side 10 has an arcuate radius of curvature R of 150 mm.