Patent Application
20050067370
1. Technical Field
The present invention relates to a bottle-shaped container made of thermoplastic resin, and intends to advantageously avoid lowering of the mechanical strength due to a light-weighted or thin-walled nature of the container.
2. Related Art
Synthetic resin containers, such as PET bottles, have been widely used as containers, e.g., for filling therein foods, beverages, cosmetics or medicines since such containers are light in weight and can thus be easily handled, have transparency to exhibit a refined appearance comparable to glass containers, and can be produced at low cost.
Synthetic resin containers have a relatively low mechanical strength against external forces. Therefore, when the container is gripped at its main body portion for pouring the contents out of the container, the container inevitably undergoes deformation at its gripped part.
It is thus a typical countermeasure to appropriately control the container wall thickness and form longitudinal ribs, lateral ribs or waists (i.e., circumferential grooves surrounding the main body portion) so as to improve the resistances of the container to external forces, such as rigidity, buckling strength, etc.
However, there is an increasing demand for thin-walled (or light-weighted) containers so as to reduce the resin amount to be used per one container from a standpoint of effective utilization of resources and reduction in the amount of wastes, resulting in a situation where the strength of the container is inevitably further lowered to deal with such a demand.
Particularly, in connection with PET bottles having a filling volume of about 500 milliliters, various kinds of commercial products have been recently increasingly sold by vending machines. In this instance, when such a bottle is light-weighted, there tends to be caused troubles wherein recesses are formed on the bottle at its lateral side (particularly, at its shoulder portion) due to an impact caused by dropping of the bottles from the storage down to the outlets, via chutes of the vending machines.
It is therefore an object of the present invention to provide an improved bottle-shaped container capable of retaining its initial shape even when the container is light-weighted and thin-walled.
According to the present invention, there is provided a bottle-shaped container comprising a mouth portion for discharging contents, a shoulder portion, a main body portion, and a bottom portion, wherein these portions are integrally molded and successively arranged with each other, said bottle-shaped container further comprising: an annular projection surrounding the main body portion and protruding from a surface thereof, along a boundary between the shoulder portion and the main body portion; and narrow grooves provided on both sides of the annular projection to extend along the same, respectively.
In the bottle-shaped container according to the present invention, the annular projection preferably defines the maximum dimension of the container, i.e., the maximum diameter in the case of a container having a circular cross-section.
The present invention will be described in further detail hereinafter, with reference to a preferred embodiment shown in the drawings.
In the drawings, reference numeral 1 denotes a mouth portion for discharging contents, 2 a shoulder portion arranged successively with the mouth portion 1, 3 a main body portion, and 4 a bottom portion. These portions are molded integrally with one another, by a biaxial-stretching blow molding of a preform made of a thermoplastic synthetic resin, such as polyethylene terephthalate.
Reference numeral 5 denotes an annular projection, which is formed at a boundary between the shoulder portion 2 and the main body portion 3, in the illustrated embodiment. This annular projection 5 is also integrally molded by the blow molding, so as to surround the main body portion 3 to extend over a full circle around the same.
Reference numerals 6a, 6b denote annular narrow grooves along both sides of the annular projection 5, i.e., along the upper and lower sides in the figure. In this embodiment, the narrow groove 6a has a groove width and a groove depth both larger than those of the narrow groove 6b, respectively.
Used for this size of container is about 30 grams of the resin amount per one container, and such a resin amount on one hand provides a certain degree of mechanical strength though, on the other hand, gives rise to a problem as follows. Namely, when the used amount of resin is reduced by about 20% so as to reduce the weight of the container, the obtained container is inevitably thin-walled and the mechanical strength is lowered particularly at the region from the shoulder portion 2 to the main body portion 3. Thus, a deformation in the above-mentioned region would be inevitable in a use condition wherein the container is dropped in a sideways falling posture within a vending machine.
Nonetheless, according to the present invention, the annular projection 5 functions to complement the strength over the lateral side of the container, so that the initial shape of the container is stably retained without causing any deformation even when the container is subjected to an impact, upon dropping or when the container is strongly gripped.
The narrow grooves 6a, 6b arranged on both sides of, and adjacently to the annular projection 5 function as dampers for absorbing the impact applied through the annular projection 5. Thus, the impact applied through the annular projection 5 is not directly transmitted to the shoulder portion 2, nor to the main body portion 3.
In order to effectively exhibit the functions of the annular projection 5 and the narrow grooves 6a, 6b, it is important that the annular projection 5 defines the maximum dimension of the container. Thus, in the case of a container having circular cross-section, for example, the diameter of the annular projection 5 corresponds to the maximum diameter of the container.
Although
Furthermore, although the narrow groove 6a has the groove width and the groove depth both larger than those of the narrow groove 6b, respectively, in the illustrated embodiment, the present invention is not limited to this embodiment and it is possible to appropriately set the groove widths and/or groove depths of the narrow grooves 6a, 6b and the width and/or projection amount (or diameter) of the annular projection 5, depending upon the size of the container. It is further preferred to provide rounded areas at corner portions of the narrow grooves 6a, 6b and annular the projection 5, respectively, so as to avoid stress concentrations. Additionally, the annular projection 5 is not limited to one in number as in the illustrated embodiment, and it is also possible to provide a plurality of annular projections.
While the present invention has been explained above with reference to a specific embodiment wherein the annular projection 5 and the narrow grooves 6a, 6b adjacent thereto are provided at the boundary between the shoulder portion 2 and main body portion 3, it is possible to appropriately provide the annular projection 5 and the narrow grooves 6a, 6b at suitable locations where an enhanced strength is required.
It will be appreciated from the foregoing description that, according to the present invention, the mechanical strength of the container can be ensured by the annular projection even when the used resin amount is reduced and the container is thin-walled to reduce the weight of the container, thereby enabling the initial shape inherently possessed by the container to be stably retained.
It is needless to say that the present invention is not limited to the above-mentioned embodiments, and may be carried out with numerous variants.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2001-294098 | Sep 2001 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP02/09776 | 9/24/2002 | WO |
