Container

Abstract

To prevent a flange of a cover body from floating.SOLUTION: A container comprises a storage body provided with a substantially polygonal opening on a top face, and a cover body for closing the opening by being attached to the storage body in an attachable / detachable manner by an inner engagement system. The storage body comprises a storage side peripheral edge part that regulates the opening. The storage side peripheral edge part includes at least one side area corresponding to at least one side of a substantially polygonal shape. At least the one side area includes a stress dispersion part. The cover body having a shape corresponding to the storage side peripheral edge part comprises a cover side peripheral edge part engaged with the storage side peripheral edge part by the inner engagement system.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] One aspect of the present disclosure relates to a container.

Background Art

[0002] Containers that are substantially polygonal and adopt an inner fitting method are known. For example, all of Patent Documents 1 to 3 describe containers that are substantially rectangular and adopt an inner fitting method.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a container that is substantially polygonal and adopts an inner fitting method, it is necessary to increase the fitting strength so that contents such as liquid do not leak from the container body closed by the cover body. However, when the fitting strength is increased, a part of the flange of the cover body fitted to the container body may float in a direction away from the container body. Such floating of the flange may rather cause leakage of the contents. Therefore, a container that can prevent the flange of the cover body from floating is desired.

Means for Solving the Problems

[0005] A container according to one aspect of the present disclosure includes a container body having a substantially polygonal opening on its top surface, and a cover body that is detachably attached to the container body by an inner fitting method to close the opening. The container body includes a container-side peripheral edge portion that defines the opening, the container-side peripheral edge portion includes at least one side region corresponding to at least one side of the substantially polygon, each of the at least one side regions includes a stress dispersion portion, and the cover body has a shape corresponding to the container-side peripheral edge portion and includes a cover-side peripheral edge portion that fits into the container-side peripheral edge portion by an inner fitting method.

[0006] In such an aspect, since the stress dispersion portion is provided in the side region of the container-side peripheral edge portion of the container body that is pushed by the cover body due to the inner fitting method, the stress in the side region is dispersed without concentrating on a specific location. Therefore, it is possible to prevent the flange of the cover body from lifting due to stress concentration.

Advantages of the Invention

[0007] According to one aspect of the present disclosure, it is possible to prevent the flange of the cover body from lifting.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0009] [Overview of the Container] Hereinafter, with reference to the accompanying drawings, the container according to the present disclosure will be described in detail. A container is an article for containing contents. The container includes a container body for containing the contents and a cover body detachably attached to the container body. The container body has a substantially polygonal opening on its top surface. The cover body closes the opening when attached to the container body. When the opening is closed by the cover body, the direction from the container body to the cover body is defined. In the present disclosure, this direction is referred to as the height direction, and the direction orthogonal to the height direction is referred to as the horizontal direction. In the height direction, the container body side is referred to as the lower side, and the cover body side is referred to as the upper side. The top surface is a virtual surface that faces the bottom surface of the container body and is located at the upper end of the container body.

[0010] The contents refer to tangible substances contained in the container. The contents may be foods such as rice, noodles, cooked mixed vegetables, soup, and seasonings. The contents may be solids, liquids, mixtures of solids and liquids, or gel-like substances, and the contents may be contained in the container in any state.

[0011] In one example, the container includes a container body for containing the contents and a lid body detachably attached to the container body. As another example, the container may further include a middle plate that divides the internal space of the container body into an upper space and a lower space. In this case, the middle plate is detachably attached to the container body, and the lid body is detachably attached to the middle plate, whereby the container forms a sealed upper space and a lower space. Similar to the container body, the middle plate can also be used to contain the contents. As shown in these examples, examples of the container body include the container body and the middle plate, and examples of the cover body include the lid body and the middle plate. Examples of combinations of the container body and the cover body include the combination of the container body and the lid body, the combination of the container body and the middle plate, and the combination of the middle plate and the lid body.

[0012] An internal fitting method is adopted to attach the cover body to the container body. The internal fitting method is a mechanism in which the fitting portion of the cover body fits into the fitting receiving portion provided inside the opening of the container body. In the internal fitting method, since the fitting portion of the cover body fitted into the container body applies pressure outward toward the opening of the container body, the cover body is difficult to come off from the container body. As a result, leakage of the contents from the container body is prevented or suppressed. Fitting refers to a method in which the fitting portion that has advanced from the first side (for example, upward) toward the fitting receiving portion to the second side (for example, downward) overrides the retaining portion constituting the fitting receiving portion and fits into the fitting receiving portion.

[0013] In order to prevent leakage of the contents from the container body, it is necessary to strongly adhere the cover body to the container body. Therefore, in the design of the container, the fitting strength, which is the force required to fit the cover body to the container body, is set high. However, if the fitting strength becomes too high, the stress in the container body with the cover body fitted therein increases, and moreover, the stress concentrates at a specific location of the container body. In the internal fitting method, due to this concentration of stress, the container body pushes the cover body toward the inside of the container, and the force due to this pushing reaches the flange of the cover body without a place to escape. As a result, a part of the flange floats upward, that is, in a direction away from the container body. Such a floating phenomenon is likely to occur in the side region corresponding to the side of a substantially polygon in the plan view of the container.

[0014] FIG. 1 is a schematic side view of a container in which such floating has occurred. The container 8 shown in this example includes a container body 81 as the container body and a lid body 82 as the cover body. In this example, a floating 9 has occurred at the central portion of the flange 82a of the lid body 82.

[0015] The floating of the flange may rather lead to leakage of the contents. In addition, the floating of the flange means deformation of the container, so there is a possibility of causing problems in the production process of the product using the container (for example, the production line of food). In addition, during the distribution process of the product, something may get caught on the floating portion, which may also cause the cover body to open unintentionally.

[0016] In one example, the container according to the present disclosure has a structure capable of preventing the flange of the cover body from lifting. Alternatively, in addition to preventing such lifting, the container has a structure enabling at least one of reliable prevention of leakage of the contents and maintenance of the operability of the container. The operability of the container means that it is easy for a person or a device to firmly fit the cover body onto the container body. Correspondingly, the operability of the container may also include making it easy for a person or a device to remove the cover body from the container body.

[0017] [Structure of the container] With reference to FIGS. 2 to 4, the structure of a container 1 according to an example will be described. FIG. 2 is an exploded perspective view of the container 1. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. FIG. 4 is a plan view of the container body 10 and a bottom view of the lid body 20.

[0018] The container 1 includes a container body 10 as a container body and a lid body 20 as a cover body. All of these components are manufactured by forming a synthetic resin sheet material into a predetermined shape using a predetermined mold.

[0019] The container body 10 may be made of a non-foamed sheet material. The non-foamed sheet material may be polyethylene terephthalate, polystyrene, or a polyolefin such as polypropylene or polyethylene. The non-foamed sheet material may contain inorganic components such as calcium carbonate, talc, and filler, and may be a sheet with improved heat resistance. The non-foamed sheet material may be multilayer or single layer. A film may be attached to the non-foamed sheet material. The non-foamed sheet material may be transparent or may have various colors or patterns. Various additives may be added to manufacture the non-foamed sheet material. The container body 10 may be made of a sheet material of a foamed synthetic resin. The sheet material of the foamed synthetic resin may be polyethylene terephthalate, polystyrene, or a polyolefin such as polypropylene or polyethylene. For example, an expanded polystyrene sheet obtained by foaming polystyrene, or a heat-resistant expanded polystyrene sheet obtained by foaming polystyrene with excellent heat resistance may be used. That is, regardless of whether the sheet material is a foam, the container body 10 may be made of a sheet material of a synthetic resin. The synthetic resin may contain a biodegradable component such as polylactic acid (PLA).

[0020] The lid 20 may be made of a transparent synthetic resin sheet material. The transparent synthetic resin sheet material may be polyethylene terephthalate, polystyrene, or a polyolefin such as polypropylene or polyethylene. For example, a polystyrene sheet obtained by biaxially stretching polystyrene, or a heat-resistant biaxially stretched styrenic resin sheet may be used. The lid 20 may be made of a semi-transparent or opaque synthetic resin sheet material. The non-transparent synthetic resin sheet material may be high-impact polystyrene (HIPS) with enhanced impact resistance by containing a rubber component, or PP filler (polypropylene with filler). The lid 20 may be made of a sheet material of the same material as the container body 10. The lid 20 may be made of a transparent synthetic resin sheet material regardless of the material of the container body 10. In this case, the contents contained in the container body 10 can be visually recognized from the outside.

[0021] Examples of the method for forming the container body 10 or the lid body 20 include vacuum forming, pressure air forming, vacuum pressure air forming, double-sided vacuum forming, and hot plate forming. The container body 10 or the lid body 20 can be produced by thermoforming a synthetic resin sheet by any of these methods. When using a stretched sheet, hot plate forming may be employed in which the sheet is sandwiched between a heated hot plate and a mold for forming.

[0022] The container body 10 includes a cup-shaped accommodating portion 11 for accommodating the content, and a main body side peripheral portion 12 that defines the opening of the accommodating portion 11. In a plan view of the accommodating portion 11, the main body side peripheral portion 12 has a substantially rectangular shape. In the present disclosure, the "plan view" refers to the case where an object is viewed from above along the height direction. The main body side peripheral portion 12 includes a flange 13 provided over the entire circumference. The flange 13 is formed to extend outward along the horizontal direction.

[0023] The lid body 20 includes a cover portion 21 formed to bulge upward in a dome shape to cover the opening of the container body 10, and a lid body side peripheral edge portion 22 that defines the outer edge of the opening of the cover portion 21. As shown in FIG. 3, the lid body side peripheral edge portion 22 includes a lower end portion 22a located on the lower end side of the outer peripheral wall of the cover portion 21, a bottom portion 22b extending outward along the horizontal direction from the lower end portion 22a, and a fitting wall portion 22c extending upward from the outer edge of the bottom portion 22b. The lid body side peripheral edge portion 22 exhibits a convex shape protruding downward in a cross-sectional view due to the lower end portion 22a, the bottom portion 22b, and the fitting wall portion 22c. In a plan view of the lid body 20, the lid body side peripheral edge portion 22 exhibits a substantially rectangular shape corresponding to the shape of the inner circumference of the main body side peripheral edge portion 12. A flange 23 extending outward along the horizontal direction is provided at the upper end of the fitting wall portion 22c. The flange 23 includes a pair of knobs 24 protruding outward along the horizontal direction. The pair of knobs 24 may be arranged, for example, to face each other on one diagonal line in the plan view of the lid body 20. The knob 24 can be used when removing the lid body 20 from the container body 10. The number of knobs 24 on the lid body 20 may be 1, or the knob 24 may be provided at a portion other than the corner of the lid body 20. The lid body side peripheral edge portion 22 is inserted inside the main body side peripheral edge portion 12, and the lid body side peripheral edge portion 22 is fitted to the main body side peripheral edge portion 12 by an inner fitting method in which the fitting wall portion 22c of the lid body side peripheral edge portion 22 fits inside the main body side peripheral edge portion 12. A vent hole 21a for discharging the vapor in the internal space formed by the container body 10 and the lid body 20 to the outside is provided in the cover portion 21. The vent hole 21a is realized by a flap formed by a U-shaped slit. However, the vent hole 21a may be formed by a collection of one or more small holes. Alternatively, the container 1 may not include the vent hole 21a.

[0024] A configuration for preventing the flange 23 of the lid body 20 from lifting is described. In the present disclosure, a peripheral edge portion that defines the opening of the container is referred to as a "container side peripheral edge portion". Further, a peripheral edge portion of a cover body having a shape corresponding to the container side peripheral edge portion and fitting to the container side peripheral edge portion by an inner fitting method is referred to as a "cover side peripheral edge portion". In the example of the container 1, the main body side peripheral edge portion 12 is the container side peripheral edge portion, and the lid body side peripheral edge portion 22 is the cover side peripheral edge portion.

[0025] As shown in FIG. 4, the peripheral portion 12 on the main body side includes four side regions 15 corresponding to the four sides of a substantially rectangular shape. Each side region 15 connects two corner portions 16. The four side regions 15 are distinguished as side regions 151 to 154. Each side region 15 includes a stress dispersion portion which is a structure for preventing the stress in the container main body 10 with the lid body 20 fitted therein from concentrating at a specific location of the container main body 10. In the example of FIG. 4, the stress dispersion portion is an arcuate section 19 which is convex toward the outside of the container main body 10 in a plan view of the container main body 10. In each of the four side regions 15, the entire side region 15 is the arcuate section 19. Since the substantially rectangular shape includes a pair of opposite sides, the peripheral portion 12 on the main body side includes a pair of side regions 15 corresponding to the pair of sides. Side regions 151 and 153 form a pair, and side regions 152 and 154 form another pair. Hereinafter, the arcuate sections of the side regions 151 to 154 are referred to as arcuate sections 191 to 194, respectively. A pair of arcuate sections 191 and 193 corresponding to the pair of side regions 151 and 153 are formed to be line-symmetrical with respect to a virtual line passing through the middle of the pair of side regions 151 and 153. A pair of arcuate sections 192 and 194 corresponding to the pair of side regions 152 and 154 are formed to be line-symmetrical with respect to a virtual line passing through the middle of the pair of side regions 152 and 154.

[0026] The peripheral portion 22 on the lid body side includes four side regions 25 forming a substantially rectangular shape corresponding to the peripheral portion 12 on the main body side. Each side region 25 connects two corner portions 26.

[0027] [Fitting strength] The above-mentioned fitting strength can also be said to be the strength for fitting the cover-side peripheral portion into the accommodating-side peripheral portion. This fitting strength may be 500 cN or more and 1500 cN or less, or may be 500 cN or more and 1300 cN or less. The unit "cN" means centinewton, and 1 N = 100 cN. The fitting strength is measured by a tension gauge as follows. First, fit the cover-side peripheral portion into the accommodating-side peripheral portion except for one of the plurality of corner portions of the substantially polygonal shape. Subsequently, push the last corner portion of the cover-side peripheral portion into the accommodating-side peripheral portion from above with the tension gauge, thereby fitting the entire cover-side peripheral portion into the accommodating-side peripheral portion. The fitting strength is the value indicated by the tension gauge during the fitting by pushing it in. In the container 1, the fitting strength for fitting the lid-side peripheral portion 22 into the main body-side peripheral portion 12 may be 500 cN or more and 1500 cN or less, or may be 500 cN or more and 1300 cN or less.

[0028] The reason for setting the fitting strength to 500 cN or more is to securely fit the cover body into the accommodating body so that the cover body does not accidentally come off the accommodating body. The reason for setting the fitting strength to 1500 cN or less is to maintain the operability of the container. By maintaining the operability of the container, it is possible to prevent a situation where, when attaching and detaching the cover body to and from the accommodating body, the contents spill out of the container due to excessive force.

[0029] [Modification Example] As described above, various examples of the present disclosure have been described in detail. However, the technology of the present disclosure is not limited to the above examples. Various modifications are possible without departing from the gist of the present disclosure.

[0030] In the above-mentioned container 1, the entire side region 15 is the arc-shaped section 19, but the arc-shaped section of the accommodating-side peripheral portion that functions as a stress dispersion portion may be formed in a part of the side region. A modification example thereof will be shown with reference to FIGS. 5 to 7. FIGS. 5 to 7 are all a plan view of the container body and a bottom view of the lid body according to the modification example. In each of the containers 1A, 1B, and 1C shown in FIGS. 5 to 7 and the container 1, the shapes of the accommodating-side peripheral portion and the lid-side peripheral portion along the circumferential direction are different.

[0031] The container 1A shown in Fig. 5 includes a container body 10A and a lid 20A. The body-side peripheral edge portion 12A of the container body 10A includes four side regions 15A corresponding to the four sides of a substantially rectangular shape. Each side region 15A connects two corner portions 16. The four side regions 15A are distinguished as side regions 151A, 152A, 153A, and 154A. Each side region 15A includes an arcuate section 19A located at the center. Both sides of the arcuate section 19A are formed linearly. Side regions 151A and 153A form a pair, and side regions 152A and 154A form another pair. Hereinafter, the arcuate sections of side regions 151A, 152A, 153A, and 154A are referred to as arcuate sections 191A, 192A, 193A, and 194A, respectively. The pair of arcuate sections 191A and 193A corresponding to the pair of side regions 151A and 153A are formed to be line-symmetric with respect to a virtual line passing through the middle of the pair of side regions 151A and 153A. The pair of arcuate sections 192A and 194A corresponding to the pair of side regions 152A and 154A are formed to be line-symmetric with respect to a virtual line passing through the middle of the pair of side regions 152A and 154A.

[0032] The lid-side peripheral edge portion 22A of the lid 20A includes four side regions 25A that form a substantially rectangular shape corresponding to the body-side peripheral edge portion 12A. Each side region 25A connects two corner portions 26.

[0033] The container 1B shown in Fig. 6 includes a container body 10B and a lid body 20B. The peripheral edge portion 12B on the body side of the container body 10B includes four side regions 15B corresponding to the four sides of a substantially rectangular shape. Each side region 15B connects two corner portions 16. The four side regions 15B are distinguished as side regions 151B, 152B, 153B, and 154B. Each side region 15B includes arcuate sections 19B located on both sides of a straight line portion located at the center. Side regions 151B and 153B form a pair, and side regions 152B and 154B form another pair. Hereinafter, the arcuate sections of side regions 151B, 152B, 153B, and 154B are referred to as arcuate sections 191B, 192B, 193B, and 194B, respectively. The pair of arcuate sections 191B and 193B corresponding to the pair of side regions 151B and 153B are formed to be line-symmetric with respect to a virtual line passing through the middle of the pair of side regions 151B and 153B. The pair of arcuate sections 192B and 194B corresponding to the pair of side regions 152B and 154B are formed to be line-symmetric with respect to a virtual line passing through the middle of the pair of side regions 152B and 154B.

[0034] The peripheral edge portion 22B on the lid body side of the lid body 20B includes four side regions 25B that form a substantially rectangular shape corresponding to the peripheral edge portion 12B on the body side. Each side region 25B connects two corner portions 26.

[0035] The container 1C shown in Fig. 7 includes a container body 10C and a lid 20C. The peripheral edge portion 12C on the body side of the container body 10C includes four side regions 15C corresponding to the four sides of a substantially rectangular shape. Each side region 15C connects two corner portions 16. The four side regions 15C are distinguished as side regions 151C, 152C, 153C, and 154C. Each side region 15C includes an arcuate section 19C located at the center. Both sides of the arcuate section 19C are formed linearly. The arcuate section 19C exhibits an arcuate shape with a larger curvature than the above-mentioned arcuate sections 19, 19A, and 19B. Side regions 151C and 153C form a pair, and side regions 152C and 154C form another pair. Hereinafter, the arcuate sections of side regions 151C, 152C, 153C, and 154C are referred to as arcuate sections 191C, 192C, 193C, and 194C, respectively. The pair of arcuate sections 191C and 193C corresponding to the pair of side regions 151C and 153C are formed to be line-symmetric with respect to a virtual line passing through the middle of the pair of side regions 151C and 153C. The pair of arcuate sections 192C and 194C corresponding to the pair of side regions 152C and 154C are formed to be line-symmetric with respect to a virtual line passing through the middle of the pair of side regions 152C and 154C.

[0036] The peripheral edge portion 22C on the lid side of the lid 20C includes four side regions 25C that form a substantially rectangular shape corresponding to the peripheral edge portion 12C on the body side. Each side region 25C connects two corner portions 26.

[0037] The shapes of the container and the cover are not limited to a substantially rectangular shape, and may be other substantially polygonal shapes such as a substantially pentagonal shape, a substantially hexagonal shape, or a substantially octagonal shape. In relation to the shapes of the container and the cover, the peripheral edge portion on the container side and the peripheral edge portion on the cover side may not include a pair of side regions.

[0038] The pair of arcuate sections corresponding to the pair of side regions may not be formed to be line-symmetric as described above. The container may include two or more types of arcuate sections as stress dispersion portions, for example, it may include two or more of the above-mentioned arcuate sections 19, 19A, 19B, and 19C.

[0039] In the above example, all the side regions of the accommodating-side peripheral portion include the stress dispersion portions, but some side regions may not include the stress dispersion portions. Taking the container body 10 of the container 1 as an example, any 1 to 3 of the side regions 151, 152, 153, and 154 may include stress dispersion portions such as arc-shaped sections, and the remaining side regions may not include stress dispersion portions. The statement "the accommodating-side peripheral portion includes at least one side region corresponding to at least one side of the substantially polygonal shape, and each of the at least one side regions includes a stress dispersion portion" means that at least one of the plurality of side regions included in the accommodating-side peripheral portion includes a stress dispersion portion.

[0040] The container may have a configuration in which the accommodating body and the cover body are integrally formed by a hinge portion. For such a container as well, at least one side region of the accommodating-side peripheral portion may include a stress dispersion portion.

[0041] [Appendix] As can be understood from the various examples above, the present disclosure includes the following aspects. (Appendix 1) A container including an accommodating body having an opening in a substantially polygonal shape on the top surface, and a cover body that is detachably attached to the accommodating body by an inner fitting method to close the opening, wherein the accommodating body includes an accommodating-side peripheral portion that defines the opening, the accommodating-side peripheral portion includes at least one side region corresponding to at least one side of the substantially polygonal shape, each of the at least one side regions includes a stress dispersion portion, the cover body includes a cover-side peripheral portion having a shape corresponding to the accommodating-side peripheral portion and fitting to the accommodating-side peripheral portion by the inner fitting method, Container. (Appendix 2) The fitting strength, which is the strength for fitting the cover-side peripheral portion to the accommodating-side peripheral portion, is 500 cN or more and 1500 cN or less. The container according to Appendix 1. (Appendix 3) The stress dispersion portion is an arcuate section that is convex outward from the container body in a plan view of the container body. The container according to appended note 1 or 2. (Appended note 4) At least one side includes a pair of opposing sides. At least one side region includes a pair of side regions corresponding to the pair of sides. The pair of arcuate sections corresponding to the pair of side regions are arranged to be line-symmetric with respect to an imaginary line passing through the middle of the pair of side regions. The container according to appended note 3. (Appended note 5) At least one side is all the sides of the substantially polygonal shape. At least one side region is a plurality of side regions corresponding to all the sides. The container according to any one of appended notes 1 to 4. (Appended note 6) The combination of the container body and the cover body is one of the combination of a container main body and a lid body, the combination of the container main body and a middle dish, and the combination of the middle dish and the lid body. The container according to any one of appended notes 1 to 5.

[0042] According to appended note 1, since a stress dispersion portion is provided in the side region of the housing side peripheral edge portion of the container body that is pushed by the cover body due to the inner fitting method, the stress in that side region is dispersed without concentrating at a specific location. Therefore, it is possible to prevent the flange of the cover body from lifting due to stress concentration.

[0043] According to appended note 2, the cover side peripheral edge portion and the housing side peripheral edge portion are configured such that the fitting strength is 500 cN or more and 1500 cN or less. By setting the fitting strength in this way, in addition to preventing the flange of the cover body from lifting, it is possible to surely prevent the leakage of the contents and maintain the operability of the container.

[0044] According to Supplementary Note 3, stress can be dispersed by an arcuate section formed so as to bulge outward from the container body. By forming the side regions of the container-side peripheral edge in this way, stress dispersion can be realized by a simple mechanism.

[0045] According to Supplementary Note 4, since the arcuate sections are formed to be line-symmetrical in a pair of opposing side regions, it is possible to prevent the flange of the cover body from lifting while enhancing the designability of the container.

[0046] According to Supplementary Note 5, since all side regions include stress dispersion portions, it is possible to more reliably prevent the flange of the cover body from lifting throughout the entire cover body.

[0047] According to Supplementary Note 6, it is possible to prevent the flange of the lid body fitted to the container body or the middle plate from lifting, or to prevent the flange of the middle plate fitted to the container body from lifting.

Example

[0048] Hereinafter, examples will be specifically described, but the present disclosure is not limited to these examples in any way.

[0049] Regarding the following four types of containers, the fitting strength was measured, the fitting situation of the cover body to the container body was examined, the presence or absence of liquid leakage as an example of the leakage of the contents was verified, and the presence or absence of the lifting of the flange of the cover body was verified. Hereinafter, the four types of containers are referred to as Type A, B, C, and D for convenience. The details of each type are as follows.

[0050] Type A was a container composed of a container body obtained by molding an expanded polystyrene sheet, an inner dish obtained by molding a PP filler with black coloring, and a transparent lid obtained by molding a biaxially stretched polystyrene sheet. The container body was 160 mm square and 62 mm high. The inner dish was 166 mm square and 28 mm high. The lid was 149 mm square and 13 mm high. The openings of all of the container body, the inner dish, and the lid were substantially square. The lid and the inner dish were detachably attached by an inner fitting method. However, the inner dish and the container body were detachably attached by an outer fitting method.

[0051] Type B was a container composed of a container body obtained by molding an expanded polystyrene sheet and a transparent lid obtained by molding a biaxially stretched polystyrene sheet. The container body was 151 mm wide, 126 mm long, and 33 mm high. The lid was 147 mm wide, 122 mm long, and 23 mm high. The openings of both the container body and the lid were substantially rectangular. The container body and the lid were detachably attached by an inner fitting method.

[0052] Type C was a container composed of a container body obtained by molding an expanded polystyrene sheet and a transparent lid obtained by molding a biaxially stretched polystyrene sheet. The container body was 230 mm wide, 165 mm long, and 38 mm high. The lid was 206 mm wide, 141 mm long, and 31 mm high. The openings of both the container body and the lid were substantially rectangular. The container body and the lid were detachably attached by an inner fitting method.

[0053] Type D was a container having an integral structure in which the lid and the container body were connected via a hinge portion, and was obtained by molding a biaxially stretched polystyrene sheet. In the fitted state, this container was 243 mm wide, 121 mm long, and 48 mm high.

[0054] As a tension gauge, a rod-shaped tension gauge (TK3000CNG) manufactured by Nakamura Seisakusho Co., Ltd. was used. With one of the plurality of corners of the cover body left, the cover body was fitted into the housing body, and the remaining one corner was pushed in with the tension gauge to fit the cover body into the housing body. The value indicated by the tension gauge when it was pushed in was obtained as the fitting strength. The scale of the used tension gauge was in 50 cN graduations, and the value between the graduations was read as 25 cN. Therefore, the measured values of each of the following examples and each of the comparative examples are in 25 cN graduations. Such a method for measuring the fitting strength was common in the following examples and comparative examples.

[0055] [Type A] For Type A, the housing body was a middle plate, and the cover body was a lid body. For Type A, as shown in FIG. 4, a container in which the entire side region was convex outward was treated as an example, and a container in which the entire side region was linear was treated as a comparative example. The cavities were prepared individually for each of the examples and comparative examples.

[0056] Five lid bodies were arbitrarily selected from 36 lid bodies produced by a mold having 36 cavities arranged in a 6×6 array. Then, for each of the five lid bodies, the fitting strength with respect to a common single middle plate was measured.

[0057] The fitting strengths in the five examples regarding a common single middle plate were 1300 cN, 1200 cN, 1200 cN, 1100 cN, and 1100 cN, and the average was 1180 cN.

[0058] On the other hand, the fitting strengths in the five comparative examples regarding a common single middle plate were 1350 cN, 1200 cN, 1250 cN, 1100 cN, and 1100 cN, and the average was 1200 cN.

[0059] Five trays were randomly selected from 25 trays produced by a mold having 25 cavities arranged in a 5×5 array. Then, for each of the five trays, the fitting strength with respect to a common single lid was measured.

[0060] The fitting strengths in five examples with respect to a common single lid were 1250 cN, 1275 cN, 1300 cN, 1175 cN, and 1300 cN, and the average was 1260 cN.

[0061] On the other hand, the fitting strengths in five comparative examples with respect to a common single lid were 1450 cN, 1550 cN, 1100 cN, 1100 cN, and 1375 cN, and the average was 1395 cN.

[0062] [Type B] For Type B, the container was the container body and the cover was the lid. Since Type B was a container in which the entire side region was convex outward as shown in FIG. 4, it was treated as an example. Five lids were randomly selected from 42 lids produced by a mold having 42 cavities arranged in a 7×6 array. Then, for each of the five lids, the fitting strength with respect to a common single container body was measured. The fitting strengths in five examples were 900 cN, 700 cN, 700 cN, 600 cN, and 650 cN, and the average was 710 cN.

[0063] [Type C] For Type C, the container was the container body and the cover was the lid. Since Type C was a container in which the entire side region was convex outward as shown in FIG. 4, it was treated as an example. Five lids were randomly selected from 24 lids produced by a mold having 24 cavities arranged in a 4×6 array. Then, for each of the five lids, the fitting strength with respect to a common single container body was measured. The fitting strengths in five examples were 800 cN, 850 cN, 950 cN, 700 cN, and 800 cN, and the average was 820 cN.

[0064] [Type D] For Type D, the container body was the receptacle, and the cover body was the lid. Since Type D was a container in which the entire edge region was convex outward as shown in Fig. 4, it was treated as an example. Five containers were arbitrarily selected from twelve containers produced by a mold having twelve cavities arranged in a 3×4 array. And the fitting strength was measured for each of the five containers. The fitting strengths in the five examples were 750 cN, 750 cN, 800 cN, 750 cN, and 800 cN, and the average was 770 cN.

[0065] In all examples of Types A to D, there was no lifting of the flange of the cover body and no liquid leakage occurred. Also, in any of the examples, the attachment and detachment of the cover body to and from the receptacle could be easily performed.

[0066] On the other hand, in the comparative example of Type A, even when the fitting strength was in the range of 500 cN or more and 1500 cN or less, a part of the flange of the cover body lifted up, and this lifting caused liquid leakage. In the comparative example where the fitting strength exceeded 1500 cN, in addition to such flange lifting and liquid leakage, a situation where it became difficult to fit the cover body to the receptacle also occurred. Such a decrease in operability may lead to a situation where the contents spill out of the container when the cover body is attached to and detached from the receptacle with too much force.

Explanation of Signs

[0067] 1, 1A, 1B, 1C... containers, 10, 10A, 10B, 10C... container bodies, 11... accommodating portions, 12, 12A, 12B, 12C... peripheral edge portions on the body side, 13... flanges, 15, 15A, 15B, 15C... edge regions, 19, 19A, 19B, 19C... arcuate sections, 20, 20A, 20B, 20C... lids, 21... cover portions, 21a... extraction holes, 22, 22A, 22B, 22C... peripheral edge portions on the lid side, 23... flanges, 25, 25A, 25B, 25C... edge regions.

Claims

1. A container comprising a container having a generally polygonal opening on a top surface, and a cover body that is detachably attached to the container by an internal fitting method to close the opening, the container has a container-side peripheral edge portion that defines the opening, the housing-side peripheral portion includes at least one side region corresponding to at least one side of the substantially polygonal shape, each of the at least one edge region includes a stress distribution portion; The cover body has a cover-side peripheral portion having a shape corresponding to the housing-side peripheral portion and fitted to the housing-side peripheral portion by the internal fitting method. container.

2. A fitting strength, which is a strength for fitting the cover-side peripheral portion to the housing-side peripheral portion, is 500 cN or more and 1500 cN or less.

2. The container of claim 1.

3. The stress dispersion portion is an arc-shaped section that is convex toward the outside of the container in a plan view of the container.

3. A container according to claim 1 or 2.

4. The at least one side includes a pair of opposing sides, the at least one side region includes a pair of side regions corresponding to the pair of sides, a pair of the arc-shaped sections corresponding to the pair of side regions are formed to be symmetrical with respect to a virtual line passing through a middle of the pair of side regions; 4. The container of claim 3.

5. the at least one side is all of the sides of the approximate polygon; the at least one side region is a plurality of side regions corresponding to all of the sides; 3. A container according to claim 1 or 2.

6. The combination of the container and the cover is one of a combination of a container body and a lid, a combination of the container body and an inner plate, and a combination of the inner plate and the lid.

3. A container according to claim 1 or 2.

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