JP5713423B2 - container - Google Patents

Description

  The present invention relates to a container that can be easily reduced in volume because it can be crushed with a small twisting force.

  Conventionally, plastic containers such as plastic bottles and cylindrical containers such as aluminum cans have been used as beverage and food containers.

  When this cylindrical container is discarded as it is in a collection box or the like, the collection box is immediately full and overflows, and the collection efficiency during transportation is deteriorated.

  For this reason, the cylindrical container which can reduce a volume manually is developed. For example, in a cylindrical container disclosed in Patent Document 1, a buckling pattern preliminary body is provided as a design that changes to a buckling pattern when a twist about an axis is applied. The pre-buckling pattern body includes a plurality of ridgelines extending in the height direction at intervals in the circumferential direction of the cylindrical container, a plurality of valley lines that span the upper and lower ends of two adjacent ridgelines, It is composed of concave and convex surfaces that are alternately formed between the valley lines, and changes to a buckling pattern with irregularities in the radial direction due to twisting. Then, when the buckling pattern preliminary body changes to the buckling pattern, the cylindrical container is crushed in the axial direction and the volume is reduced.

JP 2008-100724 A

  By the way, in order to crush the cylindrical container, it is necessary to apply a force more than the proof strength of the cylindrical container. However, in the container of Patent Document 1, the above proof strength is a geometric condition (height that is specific to the cylindrical structure).・ In addition to the radius and wall thickness) and material, etc., it varies depending on the shape of the pre-buckling pattern body (specifically, the number and direction of peak lines and valley lines). From this, in order to be able to crush the container of patent document 1 with a small force, it is necessary to adjust the shape of the buckling pattern preliminary body.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a cylindrical body portion, and the body portion is changed to a buckling pattern in which unevenness in the radial direction is generated by twisting. It is a container provided with a pre-buckling pattern body, and can be easily crushed with a small force, so that the container can be easily reduced in volume.

In order to achieve the above object, a container according to the present invention includes a cylindrical body portion, and the body portion is changed to a buckling pattern in which radial unevenness is generated by twisting. A body provided with a body, wherein the pre-buckling pattern body is adjacent to a plurality of ridge lines that are provided at intervals in the circumferential direction of the trunk portion and extend in the height direction of the trunk portion, respectively. A plurality of trough lines that are provided for each of the two peak lines and extend in the height direction of the trunk so as to span the upper and lower ends of the two peak lines, and between the peak lines and the trough lines The plurality of ridge lines and valley lines each have a convex surface and a concave surface that are alternately formed, and each of the plurality of ridge lines and valley lines has a predetermined inclination angle with respect to a line around the body portion connecting the upper ends or the lower ends. Extending in the height direction of the trunk portion, and the inclination angle of the ridge line and the valley line is Inside the barrel at the occurrence position of flexion pattern is adjusted such that the length of the sides is not uniform polygonal cross-section, said plurality of peaks lines or valley lines, the slope of the peak line or valley line The maximum angle or the minimum angle of the angle is set with a difference of 5% or more and 14% or less with respect to an average value of the inclination angles of the plurality of peak lines or valley lines .

  Preferably, the diameter of the trunk portion increases from one end side to the other end side in the height direction of the trunk portion.

  Preferably, a plurality of the buckling pattern preliminary bodies are formed at intervals in the height direction of the body portion.

  Also preferably, the material of the body is made of plastic resin, aluminum, steel, or paper.

  According to the present invention, by adjusting the inclination angle of the ridge line and the valley line in the buckling pattern prior body, the internal space of the trunk portion at the occurrence position of the buckling pattern becomes a predetermined polygonal cross section, and as a result, The distortion energy accumulated in the trunk when wrinkles occur in the trunk is minimized. For this reason, the container of the present invention is more resistant to torsion than a complete container with no initial irregularity (equivalent to a pre-buckling body) or an incomplete container with a different initial irregularity. Is small. More specifically, the container of the present invention has a maximum torque which is a torque load when wrinkles as radial displacements occur (when the gradient of strain energy or the gradient of total potential energy becomes an extreme value). However, it is smaller than the critical torque of a complete container having the same geometrical condition other than the initial imperfection, and the maximum torque of other incomplete containers. As a result, the container of the present invention can be easily crushed because the pre-buckling pattern body changes to a buckling pattern with a small torsional force, resulting in radial displacement.

It is the schematic of the container in Embodiment 1 of this invention. FIG. 3 is a development view of the container in the first embodiment. FIG. 3 is a schematic diagram showing a procedure for volume reduction of a container in the first embodiment. It is the sectional view on the AA line of FIG.3 (b). FIG. 3 is a schematic diagram showing a procedure for volume reduction of a container in the first embodiment. It is a perspective view which shows the state which the wrinkle generate | occur | produced in the cylindrical body by the twist of the periphery of an axis | shaft being added. It is a graph which illustrates the relationship between the distortion energy accumulate | stored in a cylindrical body, and the number of wrinkles which arise in a cylindrical body. It is a graph which illustrates the relationship between the torque load about a cylindrical body with initial imperfections, and a cylindrical body without initial imperfections, and radial displacement. It is a graph which illustrates the relationship between the torque load and radial displacement about the three cylindrical bodies from which the internal cross-sectional shape differs in the uneven | corrugated generation | occurrence | production position of radial direction. It is a graph which illustrates the relationship between the torque load about the cylindrical body in which the internal cross-sectional shape in the uneven | corrugated generation | occurrence | production position of radial direction becomes a hexagon, and radial direction displacement. It is the schematic of the container in Embodiment 2 of this invention. 6 is a development view of a container according to Embodiment 2. FIG. FIG. 10 is a schematic diagram showing a procedure for volume reduction of a container in a second embodiment. It is BB sectional drawing of FIG.13 (b). FIG. 10 is a schematic diagram showing a procedure for volume reduction of a container in a second embodiment.

  Embodiment 1 of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  As shown in FIG. 1, a container 1 according to Embodiment 1 is a plastic container formed by blow molding of a resin material such as polyethylene terephthalate, and has a cylindrical body 3 and a diameter smaller than that of the body 3. And a mouth portion 5 that is continuous with one end of the body portion 3. In this container 1, a beverage (contents) can flow into the body 3 from the opening 7 formed at the tip of the mouth 5, or the beverage in the body 3 can flow out.

  The pre-buckling pattern body 8 formed on the body 3 has a shape set based on an analysis or experiment of a buckling phenomenon caused by twisting, and includes a ridge line 9 (including 9A), a valley line 10 and , Has a convex surface 11 and a concave surface 12.

  As shown in the development view of FIG. 2, six ridgelines 9 are provided at intervals in the circumferential direction of the trunk portion 3, and each extend in the height direction of the trunk portion 3. As a result of being formed for every two adjacent ridgelines 9, six valley lines 10 are provided and extend in the height direction of the trunk 3 so as to span the upper and lower ends of the two ridgelines 9, respectively. Yes. The convex surface 11 and the concave surface 12 are alternately formed between the peak line 9 and the valley line 10. In addition, the number of installation of the peak line 9 and the valley line 10 is not limited to the above six, and can be arbitrarily set.

  The ridge line 9 and the valley line 10 extend with inclination angles α and β, respectively, with respect to the lines S1 and S2 around the trunk portion 3 connecting the upper ends or the lower ends thereof (in FIG. 1, the ridge lines). 9 shows a state where the line extends with an inclination angle α with respect to the line S2, and the valley line 10 extends with an inclination angle β with respect to the line S2.

  The container 1 having the above configuration is reduced in volume when the wall portion of the body portion 3 that is folded by twisting is folded back by a snap-through phenomenon, and is restored after the wall portion of the body portion 3 is folded back. The state in which the volume is reduced is stable. Hereinafter, the procedure for reducing the volume of the container 1 according to the first embodiment will be described with reference to FIGS.

  First, the both ends of the container 1 are gripped, and the container 1 is twisted around the axis (around the axis G). As a result, the container 1 changes from the state of FIG. 3A to the state of FIG. In the state of FIG. 3B, the buckling pattern preliminary body 8 has changed to a buckling pattern 13, and in the buckling pattern 13, wrinkles S (9) and S (10 (10) along the peak line 9 and the valley line 10 are obtained. ) And the convex surface 11 and the concave surface 12 are bent with the wrinkles S (9) and S (10) as creases, thereby generating radial irregularities. And as a result of the buckling pattern preliminary body 8 changing to the buckling pattern 13, the container 1 is crushed in the axial direction and the volume is reduced.

  FIG. 4 is a cross-sectional view taken along line AA in FIG. The inside of the trunk portion 3 at the position where the buckling pattern 13 is generated has a contour formed by bent walls (corresponding to the convex surface 11 and the concave surface 12). In the first embodiment, the cross section has a hexagonal shape. ing.

  And after the buckling pattern preliminary body 8 changes to the buckling pattern 13, the other end side of the trunk | drum 3 is pushed in toward one end side. As a result, a compressive force is applied to the body portion 3, and the buckling pattern 13 becomes a mountain fold shape protruding radially inward (see FIG. 5A).

  And if the other end side of the trunk | drum 3 is further pushed in toward one end side, the buckling pattern 13 will incline so that the mountain fold top part 13a may move to one end side gradually. FIG. 5B shows a state in which the inclination of the buckling pattern 13 is substantially parallel to the radial direction of the body portion 3 by the progress of the inclination.

  Further, when the other end side of the body part 3 is pushed in toward the one end side, the buckling pattern 13 is pressed inward by the wall of the body part 3 near the root 13b of the buckling pattern 13. As a result, the buckling pattern 13 is subjected to a force to reverse the root 13b as a hinge, and a snap-through phenomenon occurs. That is, after the buckling pattern 13 is in an unstable state by tilting so that the top portion 13a gradually faces one end side with the root 13b as a hinge, FIGS. 3 (c) and 5 (c) As shown in (), it is folded back to one end side in the axial direction and shifts to a stable state. By this folding, the volume of the container 1 is further reduced.

  After the buckling pattern 13 is folded back, the buckling pattern 13 is held inward by the wall of the trunk portion 3 in the vicinity of the root 13b, so that the folded state is maintained without being restored. The

  Here, in the first embodiment, the shape of the buckling pattern preliminary body 8 is set so that the container 1 can be crushed by changing from FIG. 3A to FIG. 3B with a small twisting force. Hereinafter, a method for setting the shape will be described.

  FIG. 6 shows a state in which wrinkles are generated in the cylindrical body due to the torsion around the axis. When a torsion about an axis is applied to the cylindrical body so as to gradually increase the torque load, the cylindrical body is not deformed at the initial stage where the torque load is small. However, when the torque load reaches a certain value (corresponding to a critical torque or maximum torque described later), buckling cells C that are dents in the radial direction are formed in the cylindrical body at substantially equal intervals in the circumferential direction. Starting from the bent cell C, a wrinkle S, which is an uneven displacement in the radial direction, extends in the height direction. That is, when the torque load reaches a certain value, the energy gradient becomes an extreme value, so that the cylindrical body is buckled, and a wrinkle S having a number n or an inclination angle appears. The number n and the inclination angle of the wrinkles S appearing at this time are determined according to the strain energy Vb accumulated in the cylindrical body so far.

  FIG. 7 illustrates the relationship between the strain energy Vb accumulated in the cylindrical body and the number n of wrinkles S generated in the cylindrical body. FIG. 7 shows a curve for a cylindrical body in which the strain energy Vbs that generates the number of wrinkles S is smaller than the strain energy Vb that generates the number of wrinkles S other than six. In this cylindrical body, the strain energy Vbs that generates the number of wrinkles S is smaller than the strain energy Vb that generates the other number of wrinkles S. When the strain energy Vb reaches Vbs, The energy gradient becomes an extreme value, wrinkles S are generated, and the number becomes 6.

  FIG. 8 shows the relationship between the torque load T and the radial unevenness displacement for a cylindrical body with initial imperfections and a complete cylindrical body without initial imperfections. The initial irregularity is a portion whose cross section is not a perfect circle, and corresponds to the buckling pattern preliminary body 8 in the container 1 (see FIG. 1) of the present embodiment.

  The strain energy Vbs accumulated in the cylindrical body when the wrinkle S is generated (see FIG. 7; hereinafter, the strain energy Vbs when the wrinkle is generated) is proportional to the yield strength of the cylindrical body that resists torsion, and the cylindrical body. The smaller the proof stress, the smaller the distortion energy Vbs when wrinkles occur.

  A complete cylindrical body with no initial imperfections does not produce radial displacement until a torque load T exceeding the critical torque (see FIG. 8) is applied, and the radial cylinder starts when the torque load T exceeds the critical torque. Concavity and convexity displacement occurs. On the other hand, an incomplete cylindrical body having an initial irregularity causes a radial unevenness proportional to the torque load T until the torque load T reaches a predetermined value. When the torque load T reaches a predetermined value, the strain energy Vb accumulated in the cylindrical body reaches Vbs (see FIG. 7), and the gradient of the strain energy Vb (or the gradient of the total potential energy) is an extreme value. It becomes. In this case, wrinkles S are generated in the cylindrical body as uneven displacement in the radial direction. Then, after the torque load T exceeds a predetermined value, the amount of uneven displacement per unit load becomes large, and the cylindrical body causes a sudden uneven displacement. The predetermined value is referred to as maximum torque (see FIG. 8), and this value can indicate the proof stress that resists torsion of an incomplete system cylinder.

  In addition, the proof stress that resists torsion of a complete cylindrical body can be indicated by the critical torque, but the maximum torque of the incomplete cylindrical body is smaller than the critical torque. From this, when the initial irregularities are provided in the cylindrical body, the proof stress resisting torsion is reduced, so that the strain energy Vbs (see FIG. 7) at the time of wrinkle generation is also reduced. With a small torsional force, buckling occurs and wrinkles S are generated periodically.

  When the torque load applied to the cylindrical body is further increased from the time when the wrinkle S is generated in the cylindrical body, the cylindrical body is bent with the wrinkle S as a fold, and the radial unevenness is generated. At this time, the cross-sectional shape of the inside of the cylindrical body at the position where the unevenness is generated is determined according to the number n of wrinkles S and the inclination angle λ that have been generated earlier (the inclination angle λ of the wrinkles S The extending direction is an angle inclined with respect to the circumferential direction of the cylindrical body).

  FIG. 9 illustrates the relationship between the torque load and the radial displacement for three cylindrical bodies having different internal cross-sectional shapes at the radial unevenness occurrence positions. FIG. 9 shows a balance curve for a cylinder whose section is a regular heptagon, a balance curve for a cylinder whose section is a regular pentagon, and a balance curve for a cylinder whose section is a regular hexagon. Yes.

  The above three cylinders are incomplete cylinders each having initial imperfections, and the maximum torques of these cylinders are complete cylinders (cylinders having the same geometric conditions other than initial imperfections). It is smaller than the critical torque.

  In addition, depending on the geometrical condition of the cylindrical body, the internal cross-sectional shape at the unevenness generation position causes a “dynamical symmetry breaking” in which symmetry is lowered hierarchically to an arbitrary polygon. The three cylinders have different initial irregular shapes as geometrical conditions, and thus have different cross-sectional shapes at the positions where the irregularities are generated. In these cylindrical bodies having different cross-sectional shapes, the magnitude of the maximum torque is different as shown in FIG. 9, and the smaller the maximum torque, the smaller the distortion energy Vbs (see FIG. 7) at the time of wrinkle generation, and the smaller. It is easy to cause uneven displacement in the radial direction by torsional force. In the example shown in FIG. 9, the strain energy Vbs at the time of maximum torque / wrinkle generation is small and the diameter becomes larger in the order of a cylinder having a regular heptagonal section, a cylinder having a regular pentagonal section, and a cylinder having a regular hexagonal section. Directional unevenness is likely to occur.

  In view of the above, in the first embodiment, the inside of the trunk portion 3 at the position where the buckling pattern 13 (see FIG. 3B) is generated has a polygonal cross section that minimizes the strain energy Vbs when wrinkles occur. As described above, the number of peak lines 9 and valley lines 10 and the inclination angles α and β (see FIG. 1) of the peak lines 9 and valley lines 10 are set.

Specifically, the number n _min of wrinkles S and the inclination angle λ _min of the wrinkles S when the distortion energy Vbs at the time of wrinkle generation is minimized are obtained based on the following expressions 1 and 2. Then, the number of peak lines 9 and valley lines 10 and inclination angles α and β are set so that a wrinkle S having a number n _min and an inclination angle λ _min is generated when a torsion around the axis is applied to the body 3. Is done.

Formula 1 is a formula for calculating the strain energy Vbs when wrinkles occur. Equation 2 uses the assumed number n of the wrinkles S and the inclination angle λ of the wrinkles S as input values, and the (x, y) position in the situation where the wrinkles S having the number n and the inclination angles λ are generated. A radial deflection w (x, y) is calculated. In Equations 1 and 2, E is the Young's modulus of the barrel 3, ν is the Poisson's ratio, L is the height of the barrel 3, R is the radius of the barrel 3, and t is the wall thickness of the barrel 3. A _i is an unknown coefficient set according to the inclination angle λ of the wrinkle S or the like. Moreover, in Formula 2, the support condition (boundary condition) of the edge part of a container can be set to either a simple support or a both-ends support by selecting the numerical value (1 or 2) of the power number m. .

According to Equations 1 and 2, when the deflection w (x, y) calculated by Equation 2 is input to Equation 1, when a wrinkle S having a number n or an inclination angle λ is generated, The accumulated distortion energy Vbs at the time of occurrence of wrinkles is calculated. Therefore, by obtaining the input value of Equation 2 when the output value of Equation 1 is minimized, the number n _min of wrinkles S and the inclination angle λ _min of the wrinkles S when the distortion energy Vbs at the time of wrinkle generation is minimized. Can be obtained.

In the first embodiment, the number of peak lines 9 and valley lines 10 and the inclination angles α and β are set so as to generate a wrinkle S having a number n _min and an inclination angle λ _min obtained by the equations 1 and 2. As a result, the cross-sectional shape inside the trunk portion 3 at the position where the buckling pattern 13 is generated is adjusted to a hexagon (see FIG. 4) in which the strain energy Vbs when wrinkling occurs is minimized. That is, the distortion energy Vbs at the time of wrinkle generation is adjusted to be smaller than when the cross section is another polygon. For this reason, the container 1 of the present embodiment is a complete system container without initial irregularity (corresponding to a pre-buckling pattern body) and other incomplete system containers provided with different initial irregularities, Low resistance to torsion. More specifically, the maximum torque of the container 1 is smaller than the critical torque of a complete container having the same geometric condition other than the initial imperfection and the maximum torque of other incomplete containers. Thereby, the container 1 can be easily crushed because the buckling pattern preliminary body 8 changes to the buckling pattern 13 with a small torsional force and radial displacement occurs. In addition, after the buckling pattern preliminary body 8 changes to the buckling pattern 13, the diameter of the container 1 decreases as the torsional force increases.

In addition, the number n _{min of the} wrinkles S obtained by the formulas 1 and 2 and the inclination angle λ _min of the wrinkles S are the height L of the body 3, the radius R of the body 3, the wall thickness t of the body 3, the body It varies depending on the characteristic value (Young's modulus E · Poisson's ratio ν) related to the material of the part 3. Therefore, according to the present invention, the number of peak lines 9 and valley lines 10 and the inclination angles α and β of peak lines 9 and valley lines 10 are set based on the number n _{min of} wrinkles S and the inclination angle λ _min of wrinkles S. By doing so, the cross-sectional shape inside the trunk portion 3 when the distortion energy Vbs at the time of wrinkle generation is minimized is not limited to the above hexagonal shape, and can be adjusted to an arbitrary polygon.

  And in this Embodiment 1, the cross-sectional shape inside the trunk | drum 3 in the generation | occurrence | production position of the buckling pattern 13 is adjusted further in detail so that the container 1 can be crushed with a smaller twisting force.

  FIG. 10 illustrates the relationship between the torque load and the radial displacement for a cylindrical body in which the internal cross-sectional shape at the position where the radial unevenness is generated by torsion is hexagonal.

  A first cylindrical body whose cross-sectional shape is a regular polygon and a second cylindrical body whose cross-sectional shape is a polygon with the same number of angles as the first cylindrical body, but whose side length of the polygon is non-uniform Comparing the maximum torque with the cylindrical body, as shown in the example of FIG. 10, the second cylindrical body having a non-uniform cross-sectional shape is the first cylindrical body having a regular polygonal cross-sectional shape. In contrast, the maximum torque is small, and the radial unevenness displacement is generated with a small torsional force.

  In view of this, in the present embodiment, the design of the buckling pattern preliminary body 8 is set so as to generate a non-uniform polygonal cross-sectional shape. That is, among the six ridgelines 9 (see FIG. 2) provided in the buckling pattern preliminary body 8, the inclination angle αA of one ridgeline 9A is relative to the average value of the inclination angles α of the six ridgelines 9. It is set with a difference of 5% to 14%. Specifically, the inclination angle αA of the ridgeline 9A is set to 60 °, and the inclination angles α of the other five ridgelines 9 are set to 65 °, 66 °, 65 °, 63 °, and 64 °. ing. According to this setting, the average value of the six inclination angles α is 63.3 ° (63.3 ° = (65 ° + 66 ° + 65 ° + 63 ° + 60 ° + 64 °) / 6). On the other hand, the inclination angle αA (= 60 °) of the ridgeline 9A has a difference of 5.2% (5.2% = (63.3 ° -60 °) /63.3°×100%).

  As a result, as shown in FIG. 4, the cross-sectional shape inside the trunk portion 3 at the position where the buckling pattern 13 is generated is adjusted to a hexagonal shape with nonuniform side lengths. As a result, the container 1 of the first embodiment is crushed with a small torsional force and has a smaller maximum torque than when the cross-sectional shape is a regular hexagon.

  Note that the inclination angle β of the valley line 10 may be adjusted in order to make the cross-sectional shape a non-uniform polygon. In this case, the inclination angle β of any one valley line 10 among the six valley lines 10 (see FIG. 2) provided in the buckling pattern preliminary body 8 is the average value of the inclination angles β of the six valley lines 10. On the other hand, it is set with a difference of 5% to 14%.

  Next, the container 20 of Embodiment 2 of this invention is demonstrated with reference to FIGS. 11 to 15, the same reference numerals are given to the same configurations as those in the first embodiment.

  As shown in FIG. 11, in the container 20, the body portion 21 is formed in a cylindrical shape whose diameter increases as it becomes one end side in the height direction, and a ridge line 9 and a valley line are formed in the center of the body portion 21. 10, a buckling pattern preliminary body 22 having a convex surface 11 and a concave surface 12 is formed.

Also in the present embodiment, the number and direction of the peak line 9 and the valley line 10 are set so that a wrinkle S having a number n _min and an inclination angle λ _min obtained by the expressions 1 and 2 is generated in the trunk portion 21. As a result, five ridge lines 9 and five valley lines 10 are provided, and each line S2 (a line connecting the lower ends of the ridge line 9 and the valley line 10) around the trunk portion 21 is provided. It extends in the height direction with inclination angles α and β.

  The inclination angle αA (see FIG. 12) of one peak line 9A is set with a difference of 5% or more and 14% or less with respect to the average value of the inclination angles α of the five peak lines 9. Specifically, as shown in FIG. 12, the inclination angle αA of the peak line 9A is set to 75.6 °, and the inclination angles α of the other five peak lines 9 are respectively 67.9 ° and 67.67. They are set to 9 °, 60.9 °, and 61.8 °. According to this setting, the average value of the five inclination angles α is 66.8 ° (66.8 ° = (67.9 ° + 75.6 ° + 67.9 ° + 60.9 ° + 61.8 °)) / 5) With respect to this average value, the inclination angle αA (= 75.6 °) of the ridgeline 9A has a difference of 13.2% (13.2% = (75.6 ° −66.8). °) /66.8° x 100%).

  FIG. 13 is a schematic diagram illustrating a procedure for reducing the volume of the container 20 according to the second embodiment. A process in which the container 20 is crushed will be described with reference to FIGS.

  First, when both ends of the container 20 are gripped and the container 20 is twisted about the axis (around the axis G), the container 20 changes from the state shown in FIG. 13A to the state shown in FIG. 13B. In the state of FIG. 13B, the buckling pattern preliminary body 22 is changed to the buckling pattern 23, thereby causing radial irregularities in the body portion 21. As a result, the container 20 is crushed in the axial direction. The volume has been reduced.

FIG. 14 is a cross-sectional view taken along line BB in FIG. 13B, and shows a cross-sectional shape of the body portion 21 at the position where the buckling pattern 23 is generated. In the present embodiment, the number of peak lines 9 and valley lines 10 and the inclination angles α and β of peak lines 9 and valley lines 10 are set so as to generate wrinkles S having a number n _min and an inclination angle λ _min. Thereby, the cross-sectional shape inside the trunk | drum 21 in the generation | occurrence | production position of the buckling pattern 23 is adjusted to the pentagon in which the distortion energy Vbs at the time of wrinkle generation becomes the minimum. As a result, the container 20 has a small maximum torque (a proof stress resisting torsion) and changes from the buckling pattern preliminary body 22 to the buckling pattern 23 with a small torsional force, thereby generating radial displacement. Thereby, the container 20 can be easily crushed.

  Since the inclination angle αA of the peak line 9A is set with a difference of 5% or more and 14% or less with respect to the average value of the inclination angles α of the five peak lines 9, the occurrence position of the buckling pattern 23 is generated. The cross-sectional shape inside the body 3 is adjusted to a pentagon with nonuniform side lengths. Thereby, the container 20 of this Embodiment is crushed with a small torsional force with a small maximum torque compared with the case where a cross-sectional shape becomes a regular pentagon.

  Then, as shown in FIG. 13B, after the buckling pattern preliminary body 22 is changed to the buckling pattern 23, the other end side of the body portion 21 is pushed toward one end side. As a result, a compressive force is applied to the body portion 21, and the buckling pattern 23 has a mountain fold shape protruding inward in the radial direction (see FIG. 15A).

  When the other end side of the body portion 21 is further pushed toward one end side, the buckling pattern 23 is inclined so that the top portion 23a gradually moves to one end side. As a result, FIG. As shown in FIG. 3, the inclination of the buckling pattern 23 is substantially parallel to the radial direction of the trunk portion 21.

  Then, when the other end side of the body part 21 is further pushed in toward the one end side, the buckling pattern 23 is caused by the snap-through phenomenon as shown in FIGS. 13 (c) and 15 (c). The root 23b is used as a hinge to be folded back to one end in the axial direction and stabilized. Thereby, the volume of the container 20 further decreases. In this state, the buckling pattern 23 is pressed inward by the wall of the trunk portion 21 in the vicinity of the root 23b, so that the state is maintained without being restored while being folded back. Thereby, the container 20 is reliably maintained in a state in which the volume is reduced.

  According to the second embodiment, since the diameter of the trunk portion 21 increases as it reaches the one end side, when the other end side of the trunk portion 21 is pushed into the one end side from the state of FIG. With the difference gap, the other end side of the body portion 21 can be inserted deep inside the one end side. Thereby, the buckling pattern 23 is reliably folded back to the one end side in the axial direction, and is difficult to be restored after being folded back.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, in the first and second embodiments, in order to set the number of peak lines 9 and valley lines 10 and the inclination angles α and β of the peak lines 9 and valley lines 10, the following formula 3 is used instead of formula 1. May be used. Expression 3 is a von Karman-Donnel equation, and the first term includes Expression 1 for calculating the strain energy Vbs when wrinkles occur.

  When Equation 3 is used, Equation 4 is used in addition to Equation 2 to calculate the input value to Equation 3. Equation 4 uses the assumed number n of wrinkles S and the inclination angle λ as input values in the same manner as Equation 2, and (x, y under the condition that the number n and the wrinkle λ of the inclination angle λ are generated. ) A stress φ (x, y) at the position is calculated. Also, in Formula 4, as with Formula 2, by selecting a numerical value of power m (1 or 2), the support condition (boundary condition) of the end of the container can be either simple support or double-end support. Can be set to

Then, according to Equation 3, when the deflection w (x, y) and the stress φ (x, y) assumed by Equations 2 and 4 are input, the wrinkle S having the number n and the inclination angle λ is generated. Then, the mechanical energy V stored in the body parts 3 and 21 is calculated. Therefore, the number n _min of wrinkles S and the inclination angle λ _min of the wrinkles S when the mechanical energy V is minimized are obtained by obtaining the input values of the formulas 2 and 3 when the output value of the formula 3 is the minimum. can do. The number of peak lines 9 and valley lines 10 and the inclination angles α and β of peak lines 9 and valley lines 10 are set so that wrinkles S having a number n _min and an inclination angle λ _min are generated in the body portions 3 and 21. By setting, the cross-sectional shape inside the trunk portions 3 and 21 at the generation positions of the buckling patterns 13 and 23 is adjusted to a polygon when the mechanical energy Vs is minimized. As a result, with the small twisting force of the container 20, the buckling pattern preliminary bodies 8 and 22 are changed to the buckling patterns 13 and 23, thereby causing radial irregularities.

  Moreover, the material of the trunk | drum 3 and 21 in Embodiment 1, 2 may be comprised with aluminum, steel, or paper. Even in this case, the volume of the containers 1 and 20 can be reduced by twisting the container 1 about the axis to change the buckling pattern preliminary bodies 8 and 22 into the buckling patterns 13 and 23 and compressing them. Can do.

  In addition, the buckling pattern preliminary bodies 8 and 22 in the first and second embodiments may be provided in the axial direction of the containers 1 and 20. If it does in this way, the buckling pattern 13 and 23 will arise in a several location by adding the twist around an axis | shaft to the containers 1 and 20. FIG. Thereby, the volume of the containers 1 and 20 can be reduced greatly.

  Moreover, the container of this invention can be applied also as a container which accommodates foodstuffs, such as confectionery other than the container for drinks described in the said embodiment.

  The present invention can be applied to PET bottles (including PET bottles formed from plastic resins), aluminum cans, steel cans, and paper cans as containers for containing beverages and food.

DESCRIPTION OF SYMBOLS 1,20 Container 3,21 Body part 5 Portion part 7 Opening 8,22 Buckling pattern preliminary body 9 Peak line 10 Valley line 11 Convex surface 12 Concave surface 13, 23 Buckling pattern 13a, 23a Buckling pattern top part 13b, 23b Seat Roots of bending pattern S Wrinkles S1, S2 Circumference line of body part α Inclination angle of peak line β Inclination angle of valley line λ Inclination angle of wrinkle Vb Strain energy Vbs Strain energy at the time of wrinkle generation V Mechanical energy

Claims (4)

A container provided with a cylindrical body part, and a buckling pattern preliminary body that changes to a buckling pattern in which unevenness in the radial direction is generated by twisting the body part;
The buckling pattern preliminary body is provided at intervals in the circumferential direction of the trunk part, and is provided for each of the two ridge lines adjacent to each other and a plurality of ridge lines extending in the height direction of the trunk part. A plurality of valley lines extending in the height direction of the trunk portion so as to span the upper and lower ends of the two ridge lines, and convex and concave surfaces alternately formed between the ridge lines and the valley lines. Have
The plurality of ridge lines and valley lines extend in the height direction of the trunk portion with a predetermined inclination angle with respect to a line around the circumference of the trunk portion connecting these upper ends or lower ends,
The inclination angle of the ridge line and the valley line is adjusted so that the inside of the trunk portion at the occurrence position of the buckling pattern has a polygonal cross section with nonuniform lengths of sides ,
Among the plurality of peak lines or valley lines, the maximum angle or minimum angle of the inclination angle of the peak lines or valley lines is 5% with respect to the average value of the inclination angles of the plurality of peak lines or valley lines. A container characterized by being set with a difference of 14% or less . 2. The container according to claim 1, wherein the diameter of the trunk portion increases from one end side to the other end side in the height direction of the trunk portion. The container according to claim 1 or 2 , wherein a plurality of the buckling pattern preliminary bodies are formed at intervals in the height direction of the trunk portion. The container according to any one of claims 1 to 3 , wherein the material of the barrel is made of plastic resin, aluminum, steel, or paper.

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