JP4105186B2 - Container lid - Google Patents

Description

The present invention relates to a packaging container lid formed by thermoforming a synthetic resin sheet such as compressed air vacuum forming.

A lid of a packaging container with a square or round shape in a plan view formed by vacuum-compressing a thin synthetic resin sheet, and the top surface part is formed by bending the upper edge part of the rising peripheral side surface. Widely used in foods for sale. However, this type of container lid, in addition to the thinness of the sheet, may cause the sheet to be stretched during molding, so that the upper corners are weaker than other parts, and are deformed by being crushed or distorted. It was easy. In many cases, the containers with lids are stacked in multiple stages or strongly wrapped and wrapped with a synthetic resin film.
Conventionally, as a countermeasure, a structure in which reinforcing ribs are arranged in the vertical direction on the side surface portion or from the side surface portion to the corner of the top surface has been adopted. As another structure, there is a structure in which a stepped reinforcing portion is provided at a boundary portion between the top surface and the side surface, or a convex strip portion is provided around the upper edge of the side surface or along the peripheral end portion of the top surface.

However, when the reinforcing ribs are arranged side by side, the object to be stored becomes difficult to see clearly due to the unevenness of the ribs, and the main function is impaired while being used as a container lid for exhibition. In order to eliminate the ribs, the strength is lowered, so that the sheet has to be thick, and there is a problem that the cost is increased. Also, including other structures, when the side and top are interspersed,
It was difficult to mold as a continuous surface through a curved surface.
The present invention has been made paying attention to the above problems, and without forming ribs or uneven portions, a flat surface and a top surface are formed by a thin synthetic resin sheet through a curved bent portion. It is intended to provide a lid having a configuration of an upper protrusion formed so as to be able to be increased without impairing the load compressive strength, and a simple surface configuration based on a flat surface and continuous with a curved surface. Therefore, if it is a transparent lid, it is intended to provide a lid that can be molded so that the object to be stored can be easily seen through.

In order to solve the above-mentioned problems, the present invention is formed by vacuum-compressing a thin synthetic resin sheet, having a fitting portion with a container body, an upstanding side surface , and a top surface, and having a four-corner corner portion in plan view. A quadrangular lid that continuously forms the adjacent side surfaces on both sides of each corner portion via curved ridge lines, and continuously forms the upper edge of the side surface on the horizontal top surface via curved ridge lines. Upper protrusions are formed with the curved ridges extending upwards higher than the horizontal surface of the top surface , and each upper protrusion has an upper curved surface with its top bulging outward from the lid, and upper curved surfaces on both sides of the upper protrusion. From the upper curved surface and the horizontal surface of the top surface, a concave curved inner concave surface that is recessed from the upper curved surface to the inside of the lid is formed. It has the structure.

The synthetic resin sheet is preferably formed as a sheet having a thickness of 150 to 350 μm, and the inner inclined surface is preferably formed partially or entirely as a concave curved surface.
Further, in the above, the upper protrusion is formed so that the height difference from the horizontal surface of the top surface is within 2 to 8 mm, the upper curved surface is a curved surface having a curved degree of the cut surface in the inner and outer directions is 1 to 3R, and the upper curved surface A flat surface or a concave curved surface in which the entire inner inclined surface from the top surface to the top surface falls within an angle of 10 to 40 ° with respect to the horizontal surface of the top surface, and the expansion angle near the top of the upper protrusion is 60 to 120 °, It is preferable to form both hems as a gentle slope of the same angle or more.

According to the present invention, a thin synthetic resin sheet is used to form a flat side surface and a top surface as a continuous surface via a curved bent portion without forming a stepped portion, and at an appropriate portion of the peripheral edge of the top surface. For example, if the lid has a rounded corner shape in plan view, the upper protrusions can be formed at the four corners, and the formation of the upper protrusions can increase the load compressive strength in the vicinity of the part without damaging it. A covered lid can be provided. Since the lid can have a simple surface configuration based on a flat surface and continuous with a curved surface, the lid can be a lid formed so as to easily see through the object to be stored if it is a transparent lid.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings show a preferred example and do not limit the present invention.
1 to 7 show one embodiment, FIGS. 8 and 9 show another embodiment, and FIG. 10 illustrates a strength test state in comparison with these embodiments.

  The lid 1 to which the present invention is applied is generally a synthetic resin sheet of a material as appropriate, and a thin sheet having a thickness of about 150 to 350 μm is formed by thermoforming such as compressed air vacuum forming, and is prepared with vegetables, vegetables, meat, lunch boxes, or the like. It can be suitably used as a lid for containers that store appropriate items and are displayed and sold at retail stores. The shape in plan view may be square, round, or any other shape. The stepped fitting portion 3 is formed by bending the upper end of the container 2 at the lower end of the standing side surface 2 so that it is fitted to the upper periphery of the container body. In addition, a fitting edge 4 to be fitted to the outer peripheral edge of the container main body is extended below, and a corner portion between adjacent side surfaces 2 and 2 is a curved ridge line 5, and an upper edge of the side surface 2 is a curved ridge line 6. It is formed to be continuous with the horizontal top surface 7

In the above lid, four corners of the top surface 7 , that is, the upper part of the curved ridge line 5 of the corner portion are extended upward to form an upper protrusion 8 , and the upper protrusion 8 has its top as shown in FIG. The upper edge is an upper curved surface 10 that bulges outward from the lid, and both sides of the projection have corners on both sides 2 and the curved edges 6 and 6 of the upper edge, and have gentle hems 9 and 9, and the upper curved surface. An inner inclined surface 11 that is continuous with the horizontal top surface 7 through a downwardly inclined concave curved surface that is recessed inward from the lid 10 is formed, and the inner inclined surface 11 is formed as shown in FIG. In addition, the inclined middle part is a flat inclined surface, and both the inner and outer edges are formed into a continuous surface shape with curved surfaces, or the entire inclined surface is a concave curved surface as shown in FIG. increasing the degree bending of the inner portion of the parts (small curvature) and the tails 9,9 direction as gently curved And then, alternatively, preferably formed as a surface state of these combinations. Thus, the side surface 2, the upper protrusion 8 and the top surface 7 are formed as a continuous surface via a curved surface without having a corner bent portion, and are formed so as to have a clean and good-looking configuration.

The upper protrusion 8 is formed so that the height difference H (FIG. 6B) with respect to the horizontal surface of the top surface 7 is within 2 to 8 mm, and the upper curved surface 10 has a degree of bending as viewed from the cut surface in the inner and outer directions. 1 to 3R (radius) curved surface, a flat or concave curved surface in which the entire inner inclined surface 11 from the upper curved surface 10 to the top surface falls within an angle of 10 to 40 ° with respect to the horizontal surface of the top surface 7 Even if the inner inclined surface is in an inclined state near the inside of the corner where the steepest inclination is present, the cut surface is an inclined curved surface with a degree of curvature along a circumscribed circle of about 5R with the top horizontal plane as a tangent line, The other part is a gentler inclined surface. Further, in the state of FIG. 2 as viewed from the outside of the corner (in the direction of arrow II in FIG. 1), the upper protrusion 8 has an opening angle near the top of 60 to 120 °, and both hems 9 have the same angle or higher. It is formed as a gentle flat surface or a concave curved slope opened as described above. Furthermore, in order to form the inner inclined surface 11 smoothly, the boundary between the inner inclined surface and the horizontal surface of the top surface 7 is preferably formed so as to appear as indicated by any phantom line in FIG. Large arc shape 11a in FIG.
Or, the central portion and the vicinity of both end portions in the same figure (B) are arc-shaped, and the arc approximate shape 11b is connected by a straight line between them.

The height difference H is increased by increasing the load-bearing strength of the lid corner portion to improve shape retention, and when the containers with lids are stacked, the bottom portion of the upper container is fitted into the four upper protrusions. Helps to get prevention. If it is too high, the strength will be impaired, and if it is too low, the strength will not be obtained and it will be difficult to exhibit the function of preventing displacement. The upper curved surface 10 is useful for maintaining a continuous surface without forming a corner and maintaining the load-bearing strength of the protrusion. If the curvature is too large, the strength is lowered, and if it is too small, the corner is in an angular state and a continuous surface state is obtained. It is damaged and the strength decreases. If the inner inclined surface 11 is kept within the above angle and the degree of inclination, the load bearing strength can be increased and the shape retention can be improved. If the angle is too small, the strength is impaired, and if the angle is too large, the inner surface 11 is folded. Tends to occur and the strength is easily lost. Further, if the expansion angle near the top of the upper protrusion 8 is too large or too small, the load strength tends to be impaired. It is preferable that the slopes of both hems 9 be as long as possible. If they are within the above-mentioned angle, it is useful for maintaining the load-bearing strength, and it is difficult to form the inner inclined surface 11 if it is too small or too large. And the strength is easily lost.

FIG. 10 shows a load bearing strength test, (A) is shown in FIG. 6, (B) is an embodiment of the present invention shown in FIG. 9, and (C) is a known configuration as a proportionality. A lid (protruding ridges are provided around the peripheral edge of the top surface).
The above (A) and (B) measure the yield strength (unit N) by vertically pressing the portion indicated by the round dotted line in the figure, that is, the apex portion of the upper protrusion, and the known example (C) is a round dotted line or corner. The top surface of the ridge was measured in the same manner.
The results were C = 3.71, while A = 8.36 and B = 5.95, and the strength was clearly increased by the present invention.

It is a schematic perspective view which shows an example of the lid | cover which concerns on this invention. It is the partial side view which looked at the corner part of the lid | cover from the outer side (II arrow direction of FIG. 1). It is the fragmentary sectional view which looked at the corner part from the inner side (III arrow direction of FIG. 1). It is a fragmentary top view of the corner part of the lid | cover of FIG. FIG. 5 is a partial front view of FIG. 4. 5A is a partial cross-sectional view of a corner portion of the lid of FIG. 4, and FIG. 5A is a partial cross-sectional view cut at an angle of 45 °, and FIG. 5B is an enlarged view of the upper protruding portion. It is the fragmentary top view which shows the example of a boundary of the inner inclined surface and top | upper surface of an upper protrusion, Comprising: (A) has shown the example, (B) has shown another example. It is a partial top view of the lid | cover which shows another example different from FIG. FIGS. 9A and 9B are partial cross-sectional views of a corner portion of the lid of FIG. 8, wherein FIG. 9A is a partial cross-sectional view cut at an angle of 45 °, and FIG. It is the figure which simplified the strength test method, (A) is one Example of this invention shown to FIG.4, 6, (B) is another Example of this invention shown to FIG.8,9, C) shows a known example.

Explanation of symbols

1 lid, 2 side surface, 3 fitting part, 4 fitted edge,
5 curved ridge line, 6 curved ridge line, 7 top surface, 8 upper protrusion,
9 Both hems, 10 Upper curved surface, 11 Inner inclined surface, H Height difference.

Claims (3)

A thin synthetic resin sheet is vacuum-compressed , and has a fitting part (3) with the container body, an upstanding side face (2), and a top face (7), and a substantially rectangular shape in plan view with four corners. The lid (1) of
The adjacent side surfaces (2, 2) on both sides of each corner are continuously formed through the curved ridge line (5), and the upper edge of the side surface (2) is formed into a horizontal top surface (7) through the curved ridge line (6). With continuous formation,
An upper protrusion (8) is formed by extending the curved ridge line (5) higher than the horizontal surface of the top surface (7) at each corner ,
Each of the upper protrusions (8) has an upper curved surface (10) whose top portion bulges outward from the lid, and from the upper curved surface (10) to the curved ridge line (6, 6) on both sides of the upper protrusion (8). Consecutive sloping bottoms (9, 9) are formed and are recessed from the upper curved surface (10) to the inside of the lid between the upper projection (8) and the horizontal surface of the top surface (7). A container lid structure characterized by having a configuration in which a concavely curved inner inclined surface (11) is formed .   The structure of the container lid according to claim 1, which is formed by molding a synthetic resin sheet having a thickness of 150 to 350 μm.   The upper protrusion (8) is formed so that the difference in height from the horizontal surface of the top surface (7) is within 2 to 8 mm, and the upper curved surface (10) is a curved surface with a degree of bending of the inner and outer cut surfaces being 1 to 3R. The entire inner inclined surface (11) from the upper curved surface (10) to the top surface (7) is a flat surface or a concave curved surface that falls within an angle of 10 to 40 ° with respect to the horizontal surface of the top surface (7). The container according to claim 1 or 2, wherein an expansion angle in the vicinity of the top of the protrusion (8) is 60 to 120 °, and both hems (9, 9) are formed with a gentle inclination of the same angle or more. Lid structure.