JP7640415B2 - Food packaging containers - Google Patents

Description

Applicable under Article 30, Paragraph 2 of the Patent Act <Publication A> Publication date: February 2021 Publication: Brochure introducing containers for yakitori <Publication B> Publication date: August 2021 Publication: Brochure introducing the OPB series <Publication C> Publication date: August 2021 Publication: Brochure introducing the OPB series (4 pages) [Publications, etc.] <1st> Date posted on website: April 22, 2021 Website address: https://www.denkapolymer.co.jp/ https://www.denkapolymer.co.jp/products https://www.denkapolymer.co.jp/ jp/library/5d6cf0fb26f8e9e03dc5294f/60764f0ac472f55e204740c5.pdf ≪2nd time≫ Date of website posting July 7, 2021 Website address https://www.youtube.com/watch?v=0F207NAcGCk&t=1s [Publications, etc.] Date of sale Listed in the supplementary material "List of shipping records" Place of sale Listed in the supplementary material "List of shipping records"

The present invention relates to a food packaging container for packaging foods such as skewered dumplings and yakitori.

Plastic food packaging containers for packaging foods such as skewered dumplings and yakitori are known. Food packaging containers include, for example, a container body with an opening for putting food in and taking it out, a lid that is attached to the container body to close the opening, and a hinge that connects the container body and the lid so that they can be opened and closed. With this type of packaging container, care must be taken to prevent sugar, syrup, and other sauces on the food from leaking when the lid is closed. For example, the packaging container described in Patent Document 1 includes a lid with a protruding portion that fits into the opening wall of the container body. By fitting the lid into the container body, leakage of sauces is suppressed and sealing performance is improved.

Japanese Utility Model Application Publication No. 6-76090

In this type of food packaging container, gaps can occur between the opening wall and the protrusion when they are fitted together, which can reduce the sealing performance.

The present invention aims to solve the above problems by providing a food packaging container that improves sealing when the container body is closed with the lid.

The present invention is a food packaging container for containing food, comprising a container body having an opening for putting food in and taking it out, and a lid for closing the opening, the container body having an opening wall provided along the outer periphery of the opening, the lid having a protrusion that fits into the opening wall, at least one of the opening wall and the protrusion having a corner that is bent in a convex shape and continues along the entire periphery of the opening, and the other of the opening wall and the protrusion having a curved portion that forms a concave curved surface that contacts the corner.

The opening of the container body is closed by attaching the lid. The container body has an opening wall, and the lid has a protrusion that fits into the opening wall. At least one of the opening wall and the protrusion is provided with a corner, and the other is provided with a curved portion that contacts the corner. The corner forms a contact area that is continuously closed around the entire circumference of the opening by contacting the curved portion, and this contact area acts as a dam to prevent liquid leakage, etc. Furthermore, the curved portion forms a concave curved surface in the part that contacts the corner. If it is within the concave curved surface, it is easier to form a contact area even if the corner is misaligned, improving sealing performance.

In the above food packaging container, multiple corners may be provided to contact one curved portion. By having multiple corners contact one curved portion, the contact area that stops liquid leakage increases, improving the liquid leakage prevention effect and improving sealing performance.

In the above food packaging container, the opening wall has an upper end portion surrounding the opening, and a concave inner wall portion connected to the upper end portion and into which the protrusion portion is fitted, and the curved portion is provided on the protrusion portion so as to face the connection portion between the upper end portion and the concave inner wall portion, and the concave inner wall portion may be provided with multiple corners that contact the curved portion of the protrusion portion. Even if liquid passes between the protrusion portion and the concave inner wall portion, the multiple contact areas act as a dam before the liquid exceeds the upper end portion, preventing liquid leakage.

In the above food packaging container, the opening wall has a concave inner wall portion into which the protrusion is fitted, the curved portion is provided at the lower part of the concave inner wall portion that can abut against the tip of the protrusion, and the protrusion portion may have multiple corners that contact the curved portion provided at the lower part of the concave inner wall portion. When liquid in the container body tries to seep in from the lower part of the concave inner wall portion, the multiple contact areas act as a dam to prevent liquid leakage.

The above-mentioned food packaging container may further include a hinge portion that is flexible and connects the container body and the lid in an openable and closable manner. This improves operability when opening and closing the opening of the container body with the lid.

In the above food packaging container, the corners are provided at least on the protruding portion, the curved portion is provided at least on the opening wall, and the curved portion provided on the opening wall may form a recess that resists the restoring force of the hinge portion. The corners of the protruding portion contact the concave curved surface of the curved portion. Since the curved portion forms a recess that resists the restoring force of the hinge portion, the corners contact the concave curved surface more firmly when subjected to the restoring force of the hinge portion. As a result, the sealing performance is improved.

This invention improves the sealing performance when the container body is closed with the lid.

1 is a perspective view showing an unfolded state of a food packaging container according to one embodiment of the present invention. 1 is a perspective view showing a state in which the lid of a food packaging container is closed. FIG. FIG. 2 is a plan view showing the food packaging container in an unfolded state. 2 is a plan view showing the food packaging container with the lid closed. FIG. 4 is a cross-sectional view taken along line VV in FIG. 3. 6 is an enlarged cross-sectional view showing the periphery of the hinge portion shown in FIG. 5 . 7 is a cross-sectional view taken along line VII-VII in FIG. 4. 4 is an enlarged cross-sectional view showing a protrusion portion fitted into an opening wall. FIG. FIG. 11 is an enlarged cross-sectional view showing a protrusion portion fitted into an opening wall in a modified embodiment. Photographs of a portion of a cross section of a food packaging container according to an embodiment, in which (a) is an image showing the opening wall, and (b) is an enlarged image showing the concave-side inner wall portion. Photographs of a portion of a cross section of a food packaging container according to an embodiment, in which (a) is an image showing a protrusion portion, and (b) is an enlarged image showing the convex outer wall portion.

Below, a food packaging container according to one embodiment of the present invention will be described with reference to the drawings. Note that the food packaging container of the present invention is not limited to this embodiment.

The food packaging container of the embodiment (hereinafter referred to as "container 1") is a container that contains food F (see FIG. 3) such as dumplings or yakitori. Food F is coated with sauces such as syrup or sauce, and when food F is contained in container 1, sealing properties are important to prevent the sauces from leaking out.

As shown in Figures 1, 2, 3, and 4, the container 1 comprises a container body 2 having an opening M for inserting and removing food F, a lid 3 for closing the opening M, and a hinge portion 4 for connecting the container body 2 and the lid 3 in an openable and closable manner. The lid 3 is attached so as to fit inside the opening M of the container body 2, ensuring a seal. When the lid 3 comes into contact with an obstacle such as a shopper or another product, the inside fit is less likely to come off the container body 2 than an outside fit, which is advantageous in terms of maintaining a seal.

The container 1 is manufactured, for example, using a synthetic resin sheet, and is integrally molded so that the container body 2 and the lid 3 are joined via the hinge portion 4. The container 1 according to this embodiment is transparent, but is not limited to being transparent. It is also possible to omit the hinge portion 4 and have the container body 2 and the lid 3 be independent.

The structure of the container 1 will be explained. The structure of the container 1 will be basically explained based on the state in which the lid 3 is removed and the opening M of the container body 2 is open, that is, the deployed state. In the following explanation, when the state in which the lid 3 is attached to the container body 2 and the opening M is closed is used as the reference, a supplementary explanation will be added that the state in which the lid 3 closes the opening M is used. In addition, when the explanation is given while indicating the up-down direction such as the top, bottom, upper, or lower, it is based on the container body 2 installed so that it can stably hold the food F, and it is assumed that the opening M is installed at the top. In addition, for convenience, the "horizontal direction" means a direction approximately perpendicular to the up-down direction. For example, when the vertical direction is the up-down direction, the horizontal direction is the horizontal direction. In addition, "inward" means a direction toward the inside of the container body 2, or a direction toward the inside of the container 1 when the lid 3 is closed. In addition, "outward" means a direction toward the outside, which is the opposite direction to "inward".

The container body 2 has a rough shape of a horizontally long rectangle in a plan view (see FIG. 3). The top of the container body 2 is open to form an opening M. The container body 2 has a bottom 21 provided at the bottom opposite the opening M, and a side wall 22 erected from the periphery of the bottom 21. A number of linear protrusions 21a protruding inward (upward) are arranged in a line on the bottom 21. The protrusions 21a abut against the food F contained inside, and support the food F in a state where it is slightly lifted from the bottom 21. A number of recesses 23 are formed along the periphery of the bottom 21. The back side (outer side) of the recesses 23 protrudes to form legs 24 (see FIG. 5). When viewed from the outside, the spaces between the legs 24 are recessed portions, and food labeling labels and the like are affixed to the recessed portions. The recesses 23 are provided with a number of grooves that become ribs.

As shown in Figures 1, 5 and 6, the side wall 22 includes a lower wall 25 erected from the recess 23 of the bottom 21, a middle wall 26 bent and erected from the lower wall 25, and an upper wall bent and erected from the middle wall 26. The upper wall is an opening wall 5 that receives the protrusion 7 of the lid body 3 so that it can be fitted inside, and is provided along the outer periphery of the opening M. The lower wall 25 is provided with a plurality of grooves 25a formed to be continuous with the rib grooves provided in the recess 23, forming a streamlined rib groove as a whole. The middle wall 26 bends from the lower wall 25 to project laterally, and is further bent to rise upward.

The opening wall 5 (see FIG. 6) is connected to the middle wall 26 while bending, and has a concave inner wall portion 52 that is erected while curving. The protrusion portion 7 of the cover body 3 is fitted into the concave inner wall portion 52. A force acts on the protrusion portion 7 in a direction to disengage from the internal fitting due to the restoring force of the hinge portion 4, and the concave inner wall portion 52 has a shape that can maintain the internal fitting state of the protrusion portion 7 against the restoring force of the hinge portion 4. The concave inner wall portion 52 has an inner wall lower edge portion 52a (the lower edge in FIG. 6), which is one edge connected to the middle wall 26, and an inner wall upper edge portion 52b (the upper edge in FIG. 6), which is the other edge on the opposite side.

The opening wall 5 has an upper end 54 that is bent from the inner wall upper edge 52b of the concave inner wall portion 52 and extends laterally. The upper end 54 is provided in a continuous, endless closed ring shape (e.g., a substantially rectangular ring shape) in a plan view (see FIG. 3). The inner area surrounded by the upper end 54 essentially becomes the opening M. In addition, the upper end 54 is provided so as to surround the periphery of the opening M, and the inner circumference of the upper end 54 is the periphery on the side facing the opening M. In addition, the concave side inclined portion 53 is provided along the inner circumference of the upper end 54, and serves as an introduction portion for the protrusion portion 7 of the lid body 3 that is fitted inside.

1, 3, 5, 6 and 8, the opening wall 5 includes a flange receiving portion 6 extending along the outer periphery of the upper end portion 54 and a connecting wall portion 55 connected to the hinge portion 4. The outer periphery of the upper end portion 54 means the periphery opposite to the inner periphery on the opening M side. The flange receiving portion 6 is provided so as to protrude outward from the upper end portion 54, and is a portion that abuts against the flange portion 8 of the cover body 3 when the cover body 3 is closed. The flange receiving portion 6 includes a support seat portion 61 that is provided so as to be aligned with the upper end portion 54, and a connecting portion 62 that is shifted downward from the upper end portion 54 and connects the lower portion of the connecting wall portion 55 and the support seat portion 61. The fact that the support seat portion 61 is aligned with the upper end portion 54 means that the positions in the vertical direction (height direction) are aligned. For example, the support seat portion 61 in this embodiment is provided so as to be continuous with the upper end portion 54 in a flush manner. The flange portion 8 is supported primarily by contacting the support seat portion 61.

The connection wall 55 stands upright from the hinge 4, bent at the top and connected to the upper end 54. The connection wall 55 is provided not around the entire circumference of the upper end 54, but on a portion connected to the hinge 4 (see FIG. 1). For example, the upper end 54 (see FIG. 3) is a portion that is provided to surround the opening M, which is horizontally elongated and approximately rectangular in plan view, although it is slightly curved. In other words, it can be assumed that the upper end 54 according to this embodiment has a pair of opposing long side portions and a pair of opposing short side portions. Here, of the pair of long side portions, one long side portion is the portion connected to the hinge 4 (hereinafter referred to as the "connection side region"), and the other long side portion is the opposite portion arranged to sandwich the opening M (hereinafter referred to as the "opposite side region"). The connection wall 55 is provided mainly along the connection side region, and is not provided in the opposite side region.

The connecting wall 55 (see FIG. 6) has a degree of shape stability that allows it to maintain an upright state without responding to the flexibility of the hinge 4. For example, the connection between the connecting wall 55 and the hinge 4 is bent, and the bending of the hinge 4 is absorbed by this bending and is not transmitted to the connecting wall 55. In other words, the connecting wall 55 can be described as having a structural strength that prevents continuous bending following the bending of the hinge 4, even if the hinge 4 is bent.

The connection side region and opposite side region of the upper end 54 are connected to a pair of opposing short side portions (see Figures 1 and 3). The connection wall portion 55 is provided so as to extend not only to the connection side region but also to a portion of the short side portion. The height of the connection wall portion 55 of the short side portion gradually decreases from the connection side region side to the opposite side region side, and finally disappears together at the upper end 54.

The flange receiving portion 6 extends along the outer periphery of the upper end portion 54, and is provided in the area of the entire circumference of the upper end portion 54 other than the connecting wall portion 55 in a plan view. The area of the flange receiving portion 6 that is aligned with the upper end portion 54 is the support seat portion 61, and the area that is not aligned with the upper end portion 54 and is lower than the upper end portion 54 is the connecting portion 62. The area of the flange receiving portion 6 that is aligned with the connecting wall portion 55 can also be described as the connecting portion 62, and the area that is not aligned with the connecting wall portion 55 as the support seat portion 61.

In a plan view, the hinge portion 4 extends linearly along a portion of the opening wall 5 of the container body 2. The opening wall 5 has an upper end 54, which has a connection side region as described above. The hinge portion 4 extends along the connection side region. In a cross-sectional view along the width direction perpendicular to the longitudinal direction (extension direction) of the hinge portion 4 (see FIG. 6), the hinge portion 4 has a curved shape that is approximately U-shaped and bulges downward. One end (one edge) of the hinge portion 4 in the width direction is connected to the connection wall portion 55 of the opening wall 5. The other end (the other edge) of the hinge portion 4 is connected to the hinge connection portion 9 of the lid body 3. The hinge connection portion 9 is bent and connected to the hinge portion 4, and the fold line generated by the bending is essentially the boundary between the hinge portion 4 and the hinge connection portion 9. In addition, the hinge portion 4 in this embodiment is smoothly curved without bending along the way, and has a shape that is symmetrical with respect to the center in the width direction.

The hinge portion 4 is elastically deformable and has flexibility that allows the lid body 3 to tilt toward the container body 2. For example, for the hinge portion 4 extending along the opening wall 5, the longitudinal direction is considered to be the extension direction, and the direction perpendicular to the extension direction is considered to be the width direction. Here, an axis line passing through the center of the width direction of the hinge portion 4 and along the extension direction is assumed to be the reference axis Sf. The hinge portion 4 has a main flexible portion 41 (see Figures 3 and 4) that has flexibility that allows bending around the reference axis Sf. The hinge portion 4 also has a narrowing portion 42 connected to both ends of the main flexible portion 41. The narrowing portion 42 becomes narrower in width as it moves away from the main flexible portion 41 in a plan view (see Figure 3). For example, the main flexible portion 41 (see Figure 6) has a curved shape that follows the reference axis Sf in a cross-sectional view, and extends along the reference axis Sf with a constant distance from the reference axis Sf. In contrast, the diameter of the narrowed portion 42 is reduced so that the distance from the reference axis Sf becomes narrower as the distance from the main flexible portion 41 increases. When the lid body 3 is tilted toward the container body 2 via the hinge portion 4, the narrowed portion 42 prevents the lid body 3 from wobbling left and right, stabilizing the trajectory of the lid body 3 and making it difficult for the internal fit to become misaligned.

6 and 7, the lid 3 includes a cover portion 31 that covers the opening M when attached to the container body 2, a protrusion portion 7 that protrudes from the cover portion 31 and is provided along the peripheral portion 31c of the cover portion 31, and a flexible hinge connection portion 9 that is connected to the protrusion portion 7 and the hinge portion 4. The hinge connection portion 9 may be omitted, and the protrusion portion 7 may be directly connected to the hinge portion 4.

The cover portion 31 has a shape that imitates the shape of the opening M in a plan view, and in this embodiment, it is an approximately rectangular shape that imitates the approximately rectangular opening M (see FIG. 4). The cover portion 31 is formed into a three-dimensional shape with a depth (bulge) that makes it difficult for sauces and the like applied to the food F to adhere to it. For example, based on the state in which the lid body 3 is closed (see FIG. 7), the cover portion 31 has a flat ceiling portion 31a that extends laterally, a side wall portion 31b that is provided along the outer periphery of the ceiling portion 31a so as to surround the ceiling portion 31a and is inclined downward from the outer periphery of the ceiling portion 31a, and a peripheral portion 31c that protrudes laterally outward from the lower end (edge) of the side wall portion 31b. The peripheral portion 31c corresponds to the outer periphery of the cover portion 31.

The protrusion 7 is provided along the peripheral edge 31c of the cover portion 31. For example, the protrusion 7 is provided continuously around the entire circumference of the peripheral edge 31c of the cover portion 31, and when the lid body 3 is attached to the container body 2, the entire circumference of the protrusion 7 is fitted into the opening wall 5 (see Figures 7 and 8).

The protrusion 7 is bent and rises from the peripheral edge 31c, and is formed as a whole with a shape having multiple bent portions. Specifically, the protrusion 7 has an inner surface portion 71 that rises and protrudes from the peripheral edge 31c, and an insertion end portion 72 that bends from the tip of the inner surface portion 71 and extends laterally. The inner surface portion 71 is provided continuously around the entire circumference of the peripheral edge 31c. The insertion end portion 72 is positioned so that when the protrusion 7 is fitted into the opening wall 5, it partially overlaps the concave inner wall portion 52 of the opening wall 5.

The protrusion 7 also has a convex outer wall 74 that is provided along the outer periphery of the fitting end 72. The convex outer wall 74 is a wall that bends from the outer periphery of the fitting end 72 and extends to face the inner surface 71.

The convex outer wall portion 74 is provided continuously around substantially the entire circumference of the peripheral portion 31c of the cover portion 31, and is fitted into the opening wall 5 of the container body 2. When the opening M is closed with the lid body 3, the convex outer wall portion 74 overlaps the concave inner wall portion 52 of the opening wall 5 and contacts the concave inner wall portion 52.

The convex outer wall portion 74 has one periphery 74a (the upper periphery in FIG. 6) on the side of the fitting end portion 72, and the other periphery 74b (the lower periphery in FIG. 6) on the opposite side. In this embodiment, the other periphery 74b refers to the portion connected to the hinge connection portion 9, but in a form in which the hinge connection portion 9 is omitted, it refers to the portion connected to the hinge portion 4.

The protrusion 7 has a flange 8 that extends continuously along the outer circumference of the protruding outer wall 74. The term "continuous" means that there is no missing part in the middle. The flange 8 is provided so as to protrude laterally from the protruding inclined portion 75. The flange 8 has a main mounting portion 81 that is placed on the flange receiving portion 6 of the container body 2, and a connecting mounting portion 82 that is connected to the hinge connection portion 9. The main mounting portion 81 and the connecting mounting portion 82 are connected to each other on the same plane to form an endless closed ring (approximately rectangular), and are provided continuously around the entire circumference of the protrusion 7. When the lid 3 is closed, the main mounting portion 81 is placed on the upper end portion 54 of the opening wall 5 and the flange receiving portion 6, and the connecting mounting portion 82 is placed only on the upper end portion 54.

The cover 3 has a hinge connection portion 9 disposed between the protrusion portion 7 and the hinge portion 4. The hinge connection portion 9 is connected to the protrusion portion 7 and the hinge portion 4. The hinge connection portion 9 has a lower connection portion 91, a step connection portion 92, and an upper connection portion 93. The lower connection portion 91 is connected to the hinge portion 4 and is provided so as to bend and protrude laterally from the hinge portion 4. The step connection portion 92 is connected to the lower connection portion 91 and is bent so as to be inclined relative to the lower connection portion 91. The upper connection portion 93 is provided so as to protrude laterally relative to the step connection portion 92.

Next, with reference to Figures 6 and 8, the opening wall 5 and the protrusion portion 7 that fits into the opening wall 5 will be described in detail.

When the hinge portion 4 is elastically deformed, a restoring force is generated in the hinge portion 4 that tries to return it to its original state. The restoring force of the hinge portion 4 acts as a repulsive force on the object being elastically deformed, and the object tries to resist the restoring force. In this embodiment, the opening wall 5 functions to resist the restoring force of the hinge portion 4.

To explain in detail, first, the convex outer wall portion 74 of the protrusion portion 7 is fitted into the concave inner wall portion 52 of the opening wall 5. This fitting generates a static friction force between the convex outer wall portion 74 and the concave inner wall portion 52, and this static friction force acts against the restoring force of the hinge portion 4. Furthermore, a curved portion 12 that forms a concave curved surface on the side facing the convex outer wall portion 74 is provided at the bottom of the concave inner wall portion 52. The curved portion 12 forms a recess that can accommodate the convex outer wall portion 74. For example, the hinge portion 4 elastically deforms so as to be distorted around the reference axis Sf, and the convex outer wall portion 74 moves on a predetermined trajectory in accordance with the elastic deformation at the hinge portion 4. The recess formed by the curved portion 12 of the concave inner wall portion 52 receives and holds the convex outer wall portion 74, thereby interfering with the movement trajectory of the convex outer wall portion 74 and, as a result, functioning to counter the restoring force of the hinge portion 4.

When the lid 3 closes the opening M, the concave inner wall 52 and the convex outer wall 74 are arranged to overlap. At least one of the concave inner wall 52 and the convex outer wall 74 has corners 11a, 11b, 11c, and 11d that are bent in a convex shape. This convex shape means that the concave inner wall 52 and the convex outer wall 74, which are overlapping, protrude from one side to the other. The corners 11a to 11d are each provided so as to be continuous along the entire circumference of the opening M, forming a closed ring-shaped ridge.

Of the concave inner wall portion 52 and the convex outer wall portion 74, one has corners 11a to 11d, while the other has curved portions 12, 13 that contact the corners 11a to 11d. The curved portions 12, 13 are each provided so as to continue along the entire circumference of the opening M, and contact the corners 11a, 11b or 11c, 11d around the entire circumference of the opening M. Furthermore, the curved portions 12, 13 each form a concave curved surface so as to be able to receive the convex corners 11a, 11b, 11c, 11d. The concave curved surfaces of the curved portions 12, 13 are each formed so as to continue along the entire circumference of the opening M, so as to be able to contact the corners 11a, 11b or the corners 11c, 11d around the entire circumference of the opening M.

A more detailed explanation will be given. The concave side inner wall portion 52 has multiple corners 11a, 11b. For example, the first corner 11a is provided at a position away from the inner wall upper edge portion 52b (upper connection portion), which is the connection point between the concave side inner wall portion 52 and the upper end portion 54. The second corner portion 11b is provided at a position farther away from the upper end portion 54 than the first corner portion 11a.

The concave inner wall portion 52 also has a curved portion 12. The curved portion 12 is provided so as to be curved and erected from the inner wall lower edge portion 52a, which is the connection point between the concave inner wall portion 52 and the middle wall 26. The curved portion 12 forms, for example, a concave curved surface having a substantially arc-shaped cross section. The center of curvature of the concave curved surface is located inside where the protrusion portion 7 is fitted. The first corner portion 11a and the second corner portion 11b are provided at a position closer to the upper end portion 54 than the curved portion 12. In addition, between the upper end portion 54 and the first corner portion 11a, a concave side inclined portion 53 is provided, which extends diagonally upward from the first corner portion 11a and outward.

The convex outer wall portion 74 has multiple corners 11c, 11d. For example, the third corner 11c is provided at a position away from the periphery 74a, which is the connection point between the convex outer wall portion 74 and the fitting end portion 72. The fourth corner 11d is provided at a position farther away from the fitting end portion 72 than the third corner 11c.

The convex outer wall 74 also includes a curved portion 13. The curved portion 13 is provided so as to be curved and erected from the peripheral edge 74b, which is the connection point between the convex outer wall 74 and the hinge connection portion 9. The curved portion 13 forms, for example, a concave curved surface having a substantially arc-shaped cross section. The center of curvature of the concave curved surface is located on the outer side, which is the opening wall 5 side, when the convex outer wall 74 is fitted inside the opening wall 5. The third corner 11c and the fourth corner 11d are provided at a position closer to the fitting end 72 than the curved portion 13. In addition, between the fitting end 72 and the third corner 11c, a convex inclined portion 73 is provided, which extends obliquely upward from the third corner 11c.

When the protrusion 7 is fitted into the opening wall 5, the first corner 11a and the second corner 11b of the concave inner wall 52 are located closer to the upper end 54 than the third corner 11c and the fourth corner 11d of the convex outer wall 74.

The curved portion 13 of the protrusion 7 is arranged to face the inner wall upper edge 52b of the opening wall 5 when the protrusion 7 is fitted into the opening wall 5. For example, the curved portion 13 is arranged to cover the inner wall upper edge 52b and the first corner 11a and second corner 11b of the opening wall 5. The first corner 11a and second corner 11b are in contact with the concave curved surface of the curved portion 13.

The curved portion 12 of the opening wall 5 is provided to face the peripheral edge 74a of the protrusion 7 when the protrusion 7 is fitted into the opening wall 5. For example, the curved portion 12 is provided at the lower part of the concave side inner wall portion 52 that can abut against the fitting end portion 72 (tip portion) of the protrusion 7, and is further provided to cover the peripheral edge 74a of the convex side outer wall portion 74 and the third corner portion 11c and the fourth corner portion 11d of the protrusion 7. The third corner portion 11c and the fourth corner portion 11d contact the concave curved surface of the curved portion 12.

Now, referring to Figure 9, we will explain the modified form of the opening wall 5 and the protrusion portion 7 that fits into the opening wall 5, focusing on the differences from the above-mentioned embodiment.

The opening wall 5 has a concave inner wall portion 52A, and the protrusion portion 7 has a convex outer wall portion 74A. The concave inner wall portion 52A has a single corner portion 11e, not multiple corners, and the convex outer wall portion 74A has a single corner portion 11g, not multiple corners. The concave inner wall portion 52A also has a curved portion 12A. The curved portion 12A is provided so as to be curved and erected from the inner wall lower edge portion 52a, forming a recess that counters the restoring force of the hinge portion 4. In other words, the curved portion 12A is provided at the lower portion of the concave inner wall portion 52A that can abut against the insertion end portion 72 (tip portion) of the protrusion portion 7, and is provided so that the concave curved surface within the recess abuts against the corner portion 11g of the convex outer wall portion 74A.

The convex outer wall portion 74A is provided with a curved portion 13A. The curved portion 13A is provided so as to face the inner wall upper edge portion 52b (upper connection portion) of the opening wall 5, and is provided so as to contact the corner portion 11e of the concave inner wall portion 52A.

In the above embodiment, multiple corners 11a, 11b are provided on the concave inner wall portion 52, and multiple corners 11c, 11d are provided on the convex outer wall portion 74. In a modified embodiment, a single corner 11e is provided on the concave inner wall portion 52A, and a single corner 11g is provided on the convex outer wall portion 74A. In addition to this embodiment, for example, multiple corners may be provided on one of the concave inner wall portion and the convex outer wall portion, and a single corner may be provided on the other.

Next, the structure in which the flange portion 8 and the flange receiving portion 6 engage with each other will be described with reference to Figures 1 to 4. The flange receiving portion 6 has a barrier portion 65 erected from the support seat portion 61. The barrier portion 65 is provided along the outer peripheral edge 6a of the flange receiving portion 6, but is partially missing to form a clearance portion 65a.

The location where the recess 65a is formed will be specifically described. The support seat 61 has a portion (opposing portion) that is disposed opposite the hinge portion 4 across the opening M, and the recess 65a is formed on both ends of the opposing portion. Note that the recess 65a may be provided in the middle of the opposing portion, rather than at the ends.

The support seat 61 has a support extension 61a that protrudes outward to correspond to the clearance 65a where the barrier 65 is missing. The support extension 61a has a recess 61b formed therein to form a gap for the flange 8 placed on it.

The flange portion 8 has a main placement portion 81 that is placed on the support seat portion 61, and a tab 85 that protrudes from the main placement portion 81. When the main placement portion 81 is placed on the support seat portion 61, it fits inside the barrier portion 65 to avoid the barrier portion 65. The contour line of the main placement portion 81 substantially corresponds to the contour line 8a of the flange portion 8, and the barrier portion 65 extends along the contour line 8a of the flange portion 8. In addition, the barrier portion 65 is provided along the outer peripheral edge 6a of the flange receiving portion 6, and the contour line 8a of the flange portion 8 (the contour line of the main placement portion 81) is set back inward closer to the opening M than the outer peripheral edge 6a of the flange receiving portion 6.

The gripping piece 85 is provided so that it fits into the clearance 65a where the barrier 65 is missing when the flange 8 is placed on the flange receiving part 6. The gripping piece 85 is placed on the support extension 61a of the flange receiving part 6. The support extension 61a is provided with a recess 61b to make it easier to grip the gripping piece 85. The outline of the gripping piece 85 is set back inward, closer to the opening M than the outer periphery of the flange receiving part 6.

Next, a method for manufacturing the container 1 will be described. The container 1 is made of a synthetic resin sheet and is formed by known sheet molding. Examples of sheet molding methods include vacuum forming, pressure forming, vacuum pressure forming, double-sided vacuum forming, and hot plate forming. In any case, the container 1 is formed by thermoforming a synthetic resin sheet. It is preferable to use a transparent synthetic resin as the material for the container 1 so that the contents inside the container 1 can be visually confirmed. Examples of transparent synthetic resins include polystyrene-based, polyethylene-based, polypropylene-based, and polyester-based synthetic resins.

In addition, in terms of the mechanical strength of the molded container 1, it is preferable that the synthetic resin sheet used for the container 1 is a stretched sheet manufactured by stretching the synthetic resin so that its molecules are oriented. In addition, biaxially stretched sheets have a better balance of physical properties than uniaxially stretched sheets, and are therefore more preferable. In particular, biaxially stretched sheets of polystyrene resin have well-balanced performance in terms of rigidity, heat resistance, transparency, environmental friendliness, and processability, making them suitable as a material for the container 1.

Next, the action and effect of the container 1 according to the above embodiment and modified embodiment will be described. The opening M of the container body 2 is closed by attaching the lid 3. The container body 2 has an opening wall 5, and the lid 3 has a protrusion 7 that fits into the opening wall 5. At least one of the opening wall 5 and the protrusion 7 has corners 11a-11d, 11e, and 11g, and the other has curved parts 12, 13, 12A, and 13A that contact the corners 11a-11d, 11e, and 11g. The corners 11a-11d, 11e, and 11g contact the curved parts 12, 13, 12A, and 13A to form a contact area that is continuously closed around the entire circumference of the opening M, and this contact area acts as a dam to prevent liquid leakage, etc. Furthermore, the curved parts 12, 13, 12A, and 13A form concave curved surfaces in the parts that contact the corners 11a-11d. If the corners 11a-11d, 11e, and 11g are within a concave curved surface, it is easier to form a contact area even if they are misaligned, improving sealing performance.

In addition, the container 1 according to the embodiment is provided so that multiple corners 11c, 11d contact one curved portion 12. Also, multiple corners 11a, 11b contact one curved portion 13. By having multiple corners 11c, 11d or 11a, 11b contact one curved portion 12 or curved portion 13, the contact area that stops liquid leakage increases, enhancing the effect of preventing liquid leakage and improving sealing performance.

In addition, the curved portion 13 of the protrusion 7 in the embodiment and modified form is arranged to face the upper edge 52b of the inner wall of the opening wall 5, and when the protrusion 7 is fitted into the opening wall 5, the corners 11a, 11b, and 11e of the concave inner wall 52 come into contact with the curved portions 13 and 13A. Therefore, even if liquid passes between the protrusion 7 and the concave inner wall 52 and 52A, the multiple contact areas act as a dam before the liquid exceeds the upper end 54, preventing leakage.

In addition, the curved portions 12, 12A of the opening wall 5 in the embodiment and modified form are provided at the lower portion of the concave side inner wall portion 52, 52A that can abut against the fitting end portion 72 of the protrusion portion 7, and when the protrusion portion 7 is fitted into the opening wall 5, the corners 11c, 11d, 11g of the protrusion portion 7 come into contact with the curved portions 12, 12A. Therefore, when liquid in the container body 2 tries to seep in from the lower portion of the concave side inner wall portion 52, 52A, the multiple contact areas act as dams to prevent liquid leakage.

The container 1 also has a hinge portion 4 that connects the container body 2 and the lid 3 in an openable and closable manner, improving operability when opening and closing the opening M of the container body 2 with the lid 3.

The curved portions 12 and 12A form recesses that counter the restoring force of the hinge portion 4, and the concave surfaces of the curved portions 12 and 12A contact the corners 11c, 11d, and 11g of the protruding portion 7. As a result, the corners 11c, 11d, and 11g contact the concave surfaces of the curved portions 12 and 12A more firmly when subjected to the restoring force of the hinge portion 4. As a result, the sealing performance is improved. In the opening wall 5 according to this embodiment, the part farthest from the upper end portion 54 when the horizontal distance is used as a reference is the corner 11b, and in the opening wall 5 according to the modified embodiment, the part farthest from the upper end portion 54 is the corner 11e. The recesses formed by the curved portions 12 and 12A can also be described as depressions formed to bulge outward from the corners 11b and 11e in the direction in which the restoring force of the hinge portion 4 acts.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Figure 10 is a photograph of a portion of a cross section of a food packaging container according to an embodiment. In Figure 10, (a) is an image showing the opening wall 5, and (b) is an enlarged image of the concave inner wall portion 52. Also, Figure 11 is a photograph of a portion of a cross section of a food packaging container according to an embodiment, with (a) being an image showing the protrusion portion 7, and (b) being an enlarged image of the convex outer wall portion 74.

The food packaging container according to this embodiment was manufactured by hot plate molding of a synthetic resin sheet. The food packaging container comprises a container body and a lid, and the container body comprises an opening wall 5 arranged along the outer periphery of the opening. The opening wall 5 comprises a concave-side inner wall portion 52, and the concave-side inner wall portion 52 is formed with a corner portion 11x and a curved portion 12x. The concave-side inner wall portion 52 also comprises a concave-side inclined portion 53 between the upper end portion 54 and the corner portion 11x.

The lid has a protrusion 7 that fits into the opening wall 5. The protrusion 7 has a convex outer wall 74, which has a corner 11y and a curved portion 13x. The convex outer wall 74 also has a convex inclined portion 73 between the fitting end 72 and the corner 11y.

When the protrusion 7 is fitted into the opening wall 5, the corner 11x of the concave inner wall 52 contacts the curved portion 13x of the convex outer wall 74, and the corner 11y of the convex outer wall 74 contacts the curved portion 12x of the concave inner wall 52. In this state, it was confirmed that the liquid (sauces, etc.) inside is stably retained and no liquid leakage occurs. As a result, according to this embodiment, the sealing performance can be improved when the container body is closed with the lid.

The present invention is not limited to the above embodiment. For example, in the above embodiment, multiple corners are provided on the concave inner wall portion, and multiple corners are also provided on the convex outer wall portion. However, it is also possible to have a configuration in which a single corner is provided on one of the concave inner wall portion and the convex outer wall portion, and a curved portion is provided on the other.

1...container (food packaging container), 2...container body, 3...lid, 4...hinge portion, 5...opening wall, 7...ridge portion, 11a-11d, 11e, 11g...corners, 12, 13, 12A, 13A...curved portion, 52...concave side inner wall portion, 52b...upper edge portion of inner wall (upper connection portion), 54...upper end portion, 72...insertion end portion (tip portion), F...food, M...opening.

Claims (6)

A food packaging container for containing food,
a container body having an opening for inserting and removing the food;
A cover for closing the opening;
The container body includes an opening wall provided along an outer periphery of the opening,
The cover includes a protrusion that is fitted into the opening wall,
The protrusion is bent in a convex shape and has a plurality of corners that are continuous along the entire circumference of the opening,
The opening wall is provided with a curved portion that forms a concave surface that contacts the multiple corners. 2. The food packaging container according to claim 1 , wherein the corner portion is provided so as to be continuous along the entire circumference of the opening, forming a closed ring-shaped ridge line. 3. The food packaging container according to claim 1 , wherein a gap is formed between the plurality of corners and between the protrusions and the curved portions . the opening wall includes a concave inner wall portion into which the protrusion portion is fitted,
the curved portion is provided on a lower portion of the concave-side inner wall portion capable of contacting a tip portion of the protrusion portion,
The food packaging container according to any one of claims 1 to 3, wherein the protrusion portion has a plurality of corners that contact the curved portion provided at the lower part of the concave side inner wall portion. The food packaging container according to any one of claims 1 to 4, further comprising a hinge portion that connects the container body and the lid in an openable and closable manner and has flexibility. The corner portion is provided at least on the protrusion portion,
The curved portion is provided at least on the opening wall,
6. The food packaging container according to claim 5, wherein the curved portion provided on the opening wall forms a recess that resists the restoring force of the hinge portion.

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