synthetic resin bowl lid

Abstract

To provide a synthetic resin-made lid for a bowl which can prevent, as much as possible, droplets adhered to an inner surface of a top surface wall of the bowl lid from staying without dropping into a bowl and thereby avoiding, as much as possible, such a problem that the droplets adhered to the inner surface of the bowl lid wets the surface of a table when the bowl lid is moved from above the bowl.SOLUTION: A synthetic resin-made lid for a bowl includes an annular top surface wall covering an open upper surface of a bowl and a latching wall hanging down from an outer peripheral edge of the top surface wall. The top surface wall has a center portion and a peripheral edge portion encircling the center portion and being continuous with an upper end of the latching wall. In a plane view, the center portion is circular and the peripheral edge portion is of an annular shape. In a cross-sectional view, an inner surface of the center portion gradually inclines outward and extends in a radial direction from the center, and an inner surface of the peripheral edge portion has an inside area which gradually inclines upward and extends outward in a radial direction, a middle area which gradually inclines and extends outward in the radial direction, and an outer area which gradually inclines upward and extends outward in the radial direction. The inner area on the inner surface of the peripheral edge portion gradually inclines upward at an inclination angle α of 30 degrees or more, and extends outward in the radial direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a synthetic resin rice bowl lid for covering the open upper surface of a rice bowl, and more particularly, but not limited thereto, to a synthetic resin rice bowl lid suitable for covering the open upper surface of a synthetic resin rice bowl in which processed foods containing heated liquids, such as noodles and soup like heated udon or soba, are stored.

Background Art

[0002] In hospitals and various schools, etc., processed foods containing noodles and soup like udon or soba are chilled and stored, and reheated when provided to patients and students. At this time, the processed foods subjected to chilled treatment are stored in a rice bowl formed of an appropriate synthetic resin, and an appropriate synthetic resin rice bowl lid is placed on the rice bowl to cover the open upper surface of the rice bowl, and heated in an appropriate manner such as heating by steam or hot air or heating by a microwave oven. The rice bowl lid includes a circular top wall covering the open upper surface of the rice bowl and a locking wall hanging down from the outer peripheral edge of this top wall.

[0003] However, when the rice bowl lid is removed from the rice bowl placed on a tray or table in order to eat the processed food heated as described above, it is not uncommon for water droplets adhering to the inner surface of the rice bowl lid to spill onto the table. In order to solve such problems, Patent Document 1 below discloses forming a cylindrical recess in the central portion of the inner surface of the top wall of the rice bowl lid and forming a step portion adjacent to the lower end edge of such a recess.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the bowl lid disclosed in Patent Document 1 is still not entirely satisfactory, and there are several problems to be solved: (1) Water droplets adhering to the area inside the cylindrical recess on the inner surface of the top wall of the bowl lid and water droplets adhering to the area outside the cylindrical recess do not flow smoothly when the bowl lid is placed on the bowl or in the initial stage of removing the bowl lid from the bowl (when the bowl lid is still positioned above the bowl), and remain there without falling into the bowl, making it impossible to sufficiently prevent water droplets adhering to the inner surface of the bowl lid from spilling onto the tray or table when the bowl lid is moved from above the bowl; and (2) Water droplets that have flowed in the boundary area between the inner peripheral edge of the top wall of the bowl lid and the inner upper end of the locking wall flow onto the table when the bowl lid is removed from the bowl.

[0006] The present invention has been made in view of the above facts, and its main technical objective is to provide a novel and improved synthetic resin bowl lid that prevents, as much as possible, water droplets adhering to the inner surface of the top wall of the bowl lid from remaining in the bowl without falling into the bowl, and thus minimizes the spillage of water droplets adhering to the inner surface of the bowl lid onto the table when the bowl lid is moved from above the bowl.

[0007] Another technical objective of the present invention, in addition to achieving the main technical objectives described above, is to provide a novel and improved bowl lid that minimizes the leakage of water droplets flowing in the boundary region between the inner peripheral edge of the top wall of the bowl lid and the inner upper end of the locking wall onto the table when the bowl lid is detached from the bowl. [Means for solving the problem]

[0008] The inventors have found that the main technical problem can be solved by providing a circular central portion of the top wall of a bowl lid in a plan view, such that in a cross-sectional view, the inner surface of the central portion gradually slopes downward from the center outward in the radial direction, and by providing a circular peripheral portion of the top wall of a bowl lid in a plan view, such that in a cross-sectional view, the inner surface of the annular peripheral portion has an inner region that gradually slopes upward inward in the radial direction, an intermediate region that gradually slopes downward inward in the radial direction, and an outer region that gradually slopes upward inward in the radial direction, and the inner region of the peripheral portion has an inclination angle α of 30 degrees or more and gradually slopes upward inward in the radial direction.

[0009] In other words, according to the present invention, as a synthetic resin bowl lid that achieves the above-mentioned main technical problem, A synthetic resin bowl lid includes a circular top wall that covers the open top surface of the bowl and a locking wall that hangs down from the outer edge of the top wall, The top wall has a central portion and a peripheral portion that surrounds the central portion and continues to the upper end of the locking wall. In the plan view, the central part is circular, and the peripheral part is annular. In the cross-sectional view, the inner surface of the central portion extends gradually downward from the center outward in the radial direction, and the inner surface of the peripheral portion is From the outer peripheral edge of the inner surface of the central part An inner region that extends with a gradual upward inclination toward the radially outward direction and From the outer edge of the inner region An intermediate region that extends with a gradual downward slope toward the radially outward direction and From the outer edge of the intermediate region It has an outer region that extends with a gradual upward inclination toward the radially outward direction, The inner region on the inner surface of the peripheral edge extends with an inclination angle α of 30 degrees or more, gradually inclining upward toward the radially outward direction. A synthetic resin bowl lid is provided, characterized by the following features.

[0010] Preferably, the inclination angle α is 40 to 50 degrees. The outer peripheral edge of the inner surface of the central part preferably extends with an inclination angle β of 20 to 40 degrees, gradually inclining downward toward the radially outward direction.

[0011] The other technical problems described above are addressed by a configuration in which the outer region on the inner surface of the peripheral edge and the inner surface of the locking wall form an angle γ of 60 to 80 degrees.

[0012] It is preferable that the outer diameter d1 of the peripheral edge of the top wall is 100 to 220 mm, and the outer diameter d2 of the central part is 55 to 125 mm. It is desirable that multiple exhaust recesses are arranged at circumferential intervals, extending from the outer peripheral edge of the outer region on the inner surface of the peripheral edge of the top wall to the lower end of the inner surface of the locking wall. [Effects of the Invention]

[0013] In a bowl lid constructed according to the present invention, when the bowl lid is placed over the bowl, and in the initial stage of removing the bowl lid from the bowl (when the bowl lid is still positioned above the bowl), water droplets adhering to the central part of the inner surface of the top wall flow toward the boundary between the central part and the peripheral part, and because the inner region of the inner surface of the peripheral part extends radially outward at an inclination angle α of 30 degrees or more, gradually inclining upward, the water droplets effectively fall into the bowl. Furthermore, water droplets adhering to the intermediate region of the peripheral part on the inner surface of the top wall flow toward the boundary region between the intermediate region and the outer region of the peripheral part, and at least a portion of them drip into the bowl, thereby minimizing the spillage of water droplets adhering to the inner surface of the bowl lid onto a tray or table when the bowl lid is moved from above the bowl.

[0014] In a configuration of the bowl lid constructed according to the present invention, where the outer region of the inner surface of the periphery and the inner surface of the locking wall form an angle γ of 60 to 80 degrees, water droplets flowing to the boundary region between the inner surface periphery of the top wall of the bowl lid and the inner surface of the upper end of the locking wall are held in place by surface tension due to the angle γ of 60 to 80 degrees between the outer region of the inner surface of the periphery and the inner surface of the locking wall, thus preventing them from spilling onto the table when the bowl lid is detached from the bowl. [Brief explanation of the drawing]

[0015] [Figure 1] Front view of the rice bowl lid configured according to the present invention. [Figure 2] Plan view of the rice bowl lid shown in FIG. 1. [Figure 3] Bottom view of the rice bowl lid shown in FIG. 1. [Figure 4] Cross-sectional view of the rice bowl lid shown in FIG. 1. [Figure 5] Cross-sectional view showing the state where the rice bowl lid shown in FIG. 1 is placed on the rice bowl.

Mode for Carrying Out the Invention

[0016] Hereinafter, a preferred embodiment of the rice bowl lid configured according to the present invention will be described in more detail with reference to the accompanying drawings.

[0017] Referring to FIGS. 1 to 4, the rice bowl lid, generally indicated by reference numeral 2 and configured according to the present invention, is composed of a circular top wall <4> and a substantially cylindrical locking wall <6> hanging from the outer peripheral edge of the top wall <4>. The top wall <4> has a central portion <8> and a peripheral portion <10> surrounding the central portion <8> and continuing to the upper end of the locking wall <6>. In the plan view, the central portion <8> is circular and the peripheral portion <10> is annular. Depending on the size of the rice bowl <20> (FIG. 5) to which the rice bowl lid <2> is applied, usually, the outer diameter <d1> of the peripheral portion <10> of the top wall <4> is about 100 to 220 mm, and the outer diameter <d2> of the central portion <8> is about 55 to 125 mm. The rice bowl lid <2> can be formed from an appropriate synthetic resin, but it is convenient that it is formed from a resin excellent in heat resistance and mechanical strength, such as polyethersulfone, melamine, polypropylene, polycarbonate, polyethylene naphthalate, polyester polycarbonate, polystyrene, polyethylene terephthalate, polysulfone, polyamide, polyphenylene sulfide, polyphenyl sulfone, syndiotactic polystyrene, polybutylene terephthalate, or polyether imide.

[0018] In the rice bowl lid <2> configured according to the present invention, the shape of the inner surface (lower surface in FIG. 4) <12> of the top wall <4> and the shape of the inner surface (inner peripheral surface) <14> of the locking wall <6> are important.

[0019] Continuing the explanation primarily with reference to Figure 4, the inner surface 16 of the central portion 8 of the top wall 4 inclines gradually downward from the center outward in the cross-sectional view, preferably forming a roughly circular arc shape and extending in a gradually downward inclination toward the radially outward direction. The inclination angle is increased at the outer peripheral edge of the inner surface 16 of the central portion 8 compared to the central portion, and it is desirable that the outer peripheral edge of the inner surface 16 of the central portion 8 has an inclination angle β of 20 to 40 degrees.

[0020] The inner surface 18 of the peripheral edge 10 of the top wall 4 has an inner region 18a, an intermediate region 18b, and an outer region 18c. In the cross-sectional view, the inner region 18a extends with a gradual upward inclination toward the radially outward direction, the intermediate region 18b extends with a gradual downward inclination toward the radially outward direction, and the outer region 18c extends with a gradual upward inclination toward the radially outward direction. It is important that the inner region 18a extends with a gradual upward inclination toward the radially outward direction with an inclination angle α of 30 degrees or more, preferably 40 to 50 degrees, preferably extending in a straight line (therefore, the inner region 18a as a whole is a frustoconical shape with an inclination angle α). When the inclination angle α is 30 degrees or more, preferably 40 to 50 degrees, when the bowl lid 2 is placed over the bowl 20, and in the initial stage of removing the bowl lid 2 from the bowl 20 (when the bowl lid 2 is still positioned above the bowl 20), water droplets adhering to the inner surface 12 of the top wall 4, particularly the inner surface 16 of the central part 8, flow radially outward and smoothly drip into the bowl 20 (Figure 5) at the boundary region between the inner surface 16 of the central part 8 and the inner surface 18 of the peripheral part 10. In contrast, when the inclination angle α is too small, even if water droplets adhering to the inner surface of the top wall 4, particularly the inner surface 16 of the central part 8, flow radially outward, they remain without dripping into the bowl 20 (Figure 5), and when the bowl lid 2 is moved from above the bowl 20 (Figure 5), the water droplets tend to flow onto the table (not shown). If the inclination angle α is excessive, there is a risk that so-called sink marks will occur at the boundary between the inner surface 16 of the central part 8 of the top wall 4 and the inner surface 18 of the peripheral part 10 during molding. It is preferable for the intermediate region 18b to extend with an inclination angle δ of 5 to 15 degrees, gradually inclining downward toward the radially outward direction. It is preferable for the outer region 18c to extend with an angle ε of 10 to 30 degrees, gradually inclining upward toward the radially outward direction.

[0021] It is preferable that the inner surface 14 of the locking wall 6 extends approximately parallel to the central axis X, and more specifically, downward radially outward at an inclination angle ζ of about 5 to 10 degrees with respect to the central axis X. Furthermore, in the bowl lid 2 constructed according to the present invention, it is important that the outer region 18c of the inner surface 18 of the peripheral edge 10 of the top wall 4 and the inner surface 14 of the locking wall 6 form an angle γ of 60 to 80 degrees. If the angle γ is too large, water droplets that have flowed to the boundary region between the outer peripheral edge of the inner surface 12 of the top wall 4 and the upper end of the inner surface of the locking wall 6 tend to be released onto the table when the bowl lid 2 is released from the bowl 20 (Figure 5) without being held there by surface tension. If the angle γ is too small, it becomes difficult to fit the bowl lid 2 onto and off the bowl 20 (Figure 5).

[0022] The outer shapes of the top wall 4 and locking wall 6 of the bowl lid 2 are substantially corresponding to the shapes of the inner surface 12 of the top wall 4 and the inner surface 14 of the locking wall 6 as described above, and therefore the top wall 4 and locking wall 6 have substantially uniform thickness throughout. Strictly speaking, in the illustrated embodiment, the thickness of the top wall 4 is locally thicker at the boundary between the central part 8 and the peripheral part 10 of the top wall 4, and at the boundary between the intermediate region and the outer region of the peripheral part, but in other parts the thickness of the top wall 4 and locking wall 6 are substantially the same.

[0023] In the illustrated embodiment, as clearly shown in Figure 3, multiple exhaust recesses 22 (three in the illustrated case) are arranged at intervals in the circumferential direction, extending from the outer peripheral edge of the outer region 18c on the inner surface 18 of the peripheral edge 10 of the top wall 4 to the lower end of the inner surface of the locking wall 6.

[0024] Figure 5 shows a bowl 20 along with the bowl lid 2 as shown in Figures 1 to 4. The bowl 20, which can be of a well-known form, has a bowl-shaped main part 24 as a whole. The bottom outer surface (lower surface) of the main part 24 is provided with three legs 26 that extend in an arc at equal intervals in the circumferential direction. The bowl 20 can also be made from a suitable synthetic resin, preferably a resin with excellent heat resistance and mechanical strength, such as polyethersulfone, melamine, polypropylene, polycarbonate, polyethylene naphthalate, polyester polycarbonate, polystyrene, polyethylene terephthalate, polysulfone, polyamide, polyphenylene sulfide, polyphenylsulfone, syndiotactic polystyrene, polybutylene terephthalate, or polyetherimide. Processed food (not shown) containing chilled noodles and soup can be stored inside such a bowl 20. Then, the lid 2 is placed over the main part 24 of the bowl 20, and the open top surface of the bowl 20 is covered by the lid 2. When stacking multiple bowls 20 with lids 2 on top, as shown by the dashed line in Figure 5, the legs 26 of the upper bowl 20 are positioned within the annular recess formed at the boundary between the central part 8 and the peripheral part 10 on the outer surface of the top wall 4 of the lower lid 2, thus allowing them to be stacked stably. After that, the processed food contained in the bowl 20 is heated by an appropriate method such as heating with steam or hot air or heating with a microwave oven, and is provided to patients in hospitals or students in various schools. If the pressure of the steam generated during heating becomes excessive, the steam is discharged through the exhaust recess 22 provided in the lid 2.

[0025] When the processed food contained in the bowl 20 includes, for example, noodles and soup, numerous water droplets adhere to the inner surface 12 of the top wall 4 of the bowl lid 2 due to the steam generated during heating. However, in the bowl lid 2 constructed according to the present invention, the water droplets adhering to the inner surface 12 of the top wall 4, particularly the inner surface of the central part 8 of the top wall 4, flow radially outward even when the bowl lid 2 is placed over the bowl 20, flowing to the boundary region between the inner surface 16 of the central part 8 and the inner surface 18 of the peripheral part 10. Since the inner region 18a of the inner surface 18 extends with an inclination angle α of 30 degrees or more, preferably 40 to 50 degrees, in the cross-sectional view, the water droplets smoothly drip into the bowl 20. Then, when the lid 2 is tilted in the initial stage of removing it from the bowl 20 in order to eat the processed food contained in the bowl 20 (while the lid 2 is still positioned above the bowl 20), the flow of water droplets remaining on the inner surface of the central part 8 of the top wall 4 is promoted, causing them to flow to a specific angular position (the lowest position) in the boundary region between the inner surface 16 of the central part 8 and the inner surface 18 of the peripheral part 10, and drip into the bowl 20. Water droplets adhering to the intermediate region 18b of the inner surface 18 of the peripheral part 10 of the top wall 4 flow towards the boundary region between the intermediate region 18b and the outer region 18c, and at least some of them drip into the bowl. Thus, when the lid 2 is moved from above the bowl 20 and placed on, for example, a tray or table (not shown), spillage of water droplets is avoided as much as possible. Furthermore, any water droplets that flow to the boundary region between the outer peripheral edge of the inner surface 12 of the top wall 4 and the upper end of the inner surface 14 of the locking wall 6 without dripping into the bowl 20 are held at the bottom by surface tension because the outer region 18c of the inner surface 18 of the peripheral edge 10 of the top wall 4 and the inner surface 14 of the locking wall 6 form an angle γ of 60 to 80 degrees, thus preventing them from flowing onto a table or tray (not shown) as much as possible.

[0026] Examples Ten bowl lids, as shown in Figures 1 to 4, were formed from polyethersulfone. The inclination angles were approximately 45 degrees, 30 degrees, 10 degrees, 20 degrees, 7 degrees, and 70 degrees, respectively. The outer diameter of the periphery of the top wall was 160 mm, and the outer diameter of the central part of the top wall was 90 mm. The thickness of the top wall and the locking wall was approximately 3 mm, except for areas where the thickness was locally increased.

[0027] In each of the ten bowl lids described above, 200g of udon noodles and 300g of liquid (udon soup) were placed inside a bowl made of polyethersulfone, as shown in Figure 5, with an outer diameter of 160mm at the top, and the bowl lid was placed over the bowl. Next, the bowl with the lid on was placed in a microwave oven and heated at 750W for 5 minutes. After that, the bowl was removed from the microwave oven and placed on a normal tray, and the lid was removed from the bowl using a standard procedure, with the inner surface of the top wall facing upwards, and placed on the tray. The temperature of the liquid inside the bowl was measured and found to be 97°C. Upon observation of the surface of the tray, no water droplets were found on any of the ten bowl lids. Upon observation of the inner surfaces of the bowl lids, some water droplets were found on the inner surfaces of the center and periphery of the top wall, as well as between the outer periphery of the inner surface of the top wall and the upper end of the inner surface of the locking wall, on all ten bowl lids. [Explanation of Symbols]

[0028] 2: Bowl lid 4: Top wall 6: Locking wall 8: Center of the top wall 10: Peripheral edge of the top wall 12: Inner surface of the top wall 14: Inner surface of the locking wall 16: Inner surface of the central part of the top wall 18: Inner surface of the periphery of the top wall 18a: Inner area 18b: Middle area 18c:Outer area 20: Donburi 22: Exhaust recess 24: Main part of the rice bowl 26: Legs

Claims

1. A synthetic resin bowl lid includes a circular top wall that covers the open top surface of the bowl and a locking wall that hangs down from the outer edge of the top wall, The top wall has a central portion and a peripheral portion that surrounds the central portion and continues to the upper end of the locking wall. In the plan view, the central part is circular, and the peripheral part is annular. In the cross-sectional view, the inner surface of the central portion extends with a gradual downward slope outward from the center, and the inner surface of the peripheral portion has an inner region that extends with a gradual upward slope outward from the outer peripheral edge of the inner surface of the central portion, an intermediate region that extends with a gradual downward slope outward from the outer peripheral edge of the inner region, and an outer region that extends with a gradual upward slope outward from the outer peripheral edge of the intermediate region. The inner region on the inner surface of the peripheral edge extends with an inclination angle α of 30 degrees or more, gradually inclining upward toward the radially outward direction. A synthetic resin bowl lid characterized by the following features.

2. The synthetic resin bowl lid according to claim 1, wherein the inclination angle α is 40 to 50 degrees.

3. The synthetic resin bowl lid according to claim 1, wherein the outer peripheral edge of the inner surface of the central part extends with an inclination angle β of 20 to 40 degrees, gradually inclining downward toward the radially outward direction.

4. The synthetic resin bowl lid according to claim 1, wherein the outer region on the inner surface of the peripheral edge and the inner surface of the locking wall form an angle γ of 60 to 80 degrees.

5. The synthetic resin bowl lid according to claim 1, wherein the outer diameter d1 of the peripheral edge of the top wall is 100 to 220 mm, and the outer diameter d2 of the central part is 55 to 125 mm.

6. A synthetic resin bowl lid according to claim 1, wherein a plurality of exhaust recesses are arranged at circumferential intervals, extending from the outer peripheral edge of the outer region on the inner surface of the peripheral edge of the top wall to the lower end of the inner surface of the locking wall.

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