EP1945517A2

EP1945517A2 - Plastic bottle

Info

Publication number: EP1945517A2
Application number: EP06810349A
Authority: EP
Inventors: Kenshi Matsuoka; Ryoichi Tomishima; Hiromasa Iwashita; Manabu Inomata
Original assignee: Coca Cola Co
Current assignee: Coca Cola Co
Priority date: 2005-09-16
Filing date: 2006-09-14
Publication date: 2008-07-23
Also published as: JP2007076717A; ZA200802086B; CN101263058A; EA200800836A1; WO2007032545A2; JP4873912B2; CN101263058B; WO2007032545A3; KR20080055878A; EA012547B1

Abstract

A plastic bottle (1) has a polygo nally-shaped bottle body, and the bottle body (4) has a concave rib (35) formed around its complete circumference. The rib (35) has a rib central circumference, a rib upper circumference adjoining the upper edge of the rib central circumference, and a rib lower circumference adjoining the lower edge of the rib central circumference. The rib central circumference is formed in a shape that is non-homothetic with that of the rib upper circumference or the rib lower circumference .

Description

i ^•

DESCRIPTION PLASTIC BOTTLE

Technical Field

The present invention relates to a plastic bottle used by being filled with liquid.

Background Art

Plastic bottles, typically PET bottles, being filled with beverages, have been widely marketed. The bottles are typically filled with beverages at a relatively high temperature (in hot-pack filling) or at a room temperature (in aseptic filling). When the bottles are hermetically sealed and cooled after the filling, the pressure inside the bottle drops. If the vacuum created in the bottle deforms the bottle wall unevenly, the bottle's commercial value will be damaged.

Many proposals have been made regarding plastic bottles that have vacuum panels on the bottle body so that vacuum-induced deformation of the bottle can be reduced. For example, Japanese Patent Laid-open Publication No. 2005-178904 discloses a bottle that has a bottle body with a tetragonal cross-section and vacuum panels formed on the body to have a tetragonal planar shape. Japanese Patent Laid-open Publication No. 2002-330222 discloses a bottle that has a bottle body with a circular cross-section and vacuum panels formed on the body to have an oval planar shape. The bodies of both bottles above are shaped, as a whole, like waistless bodies along the central axis. Also, the bodies of both bottles above have a horizontal rib formed around their circumference, and that horizontal rib increases strength against any lateral load applied externally (i.e., lateral rigidity). Moreover, the bodies of both bottles above adjoin cone-shaped bottle shoulders.

The above-mentioned conventional bottles, regardless of whether they are square bottles or circular bottles, have waistless bodies, or bodies with an almost uniform body diameter. However, considering user-friendliness in holding a bottle and drinking beverages from the bottle, the bottle body should be easier to grip. Also, while conventional bottles have a horizontal rib on the bottle body, lateral rigidity should be increased in the bottle shoulder too. Moreover, the shapes of the horizontal rib and vacuum panels should also be improved further.

Disclosure of Invention

An object of the present invention is to provide a plastic bottle that is easy to grip. A second object of the invention is to provide a plastic bottle that has sufficient rigidity for manufacture and distribution. A third object of the invention is to provide a plastic bottle that has improved ability to accommodate any vacuum created in the bottle.

In order to achieve the first object, the invention provides a plastic bottle including: a mouth portion capable of receiving a detachable cap that attaches thereto; a shoulder portion adjoining the mouth portion; and a body portion adjoining the shoulder portion. The body portion has: a waist portion that includes a portion whose distance from its central axis to its outer wall is the . shortest in the body portion, and that also has a specific cross sectional shape; an upper body portion formed so that it enlarges and broadens gradually or step-by- step from the waist portion upward along the central axis; and a lower body portion formed so that it enlarges and broadens gradually or step-by-step from the waist portion downward along the central axis. The ratio of the distance L2 from the central axis to a given point on the outer wall at the waist portion, to the longest distance L1 from the central axis to the outer wall of the body portion, is set to be between 71% and 90% inclusive.

When defining the relationship between the distances L1 and L2 by their size, instead of defining it by the ratio between them, L1 may be set to be between 30 mm and 35 mm inclusive and L2 may be set to be between 25 mm and 27 mm inclusive.

With such a configuration, the body portion has the upper body portion and the lower body portion formed above and below the waist portion. Since the relationship between the distance l_2 in the waist portion and the distance l_1 in the body portion is set as above, the body portion can be easily gripped at the waist portion. If the above L2/L1 ratio is less than 71%, the bottle volume decreases and problems are likely to occur in the bottle molding. Meanwhile, if the ratio is over 90%, the effect of the waist portion achieving the easy grip of the bottle tends to be lessened.

Preferably, the waist portion is positioned 20 mm or less from the center of gravity of the plastic bottle. . .

With such a configuration, the bottle can be more user-friendly, for example, in being easier to grip.

Preferably, the specific cross sectional shape of the waist portion is a polygon.

With such a configuration, since the position that users practically grip to hold the bottle is formed in a polygonal shape, the user's hands are less likely to slip on the bottle, for example in screwing or unscrewing the bottle cap, and so the bottle can be more user-friendly,

Preferably, the polygon is a polygon with an even number of angles, for manufacturing reasons. An approximate hexagon is particularly preferable.

More preferably, each corner of the approximate hexagon is at least either chamfered or rounded.

With such a configuration, the plastic bottle can be held by users comfortably at the waist portion.

Preferably, a concave rib is formed in the polygonally-shaped waist portion. More preferably, the rib is formed around the complete circumference of the waist portion.

With such a configuration, the lateral rigidity in the waist portion can increase. Here, the rib may also be formed discontinuously along the circumference.

Preferably, the rib has a rib central circumference, a rib upper circumference adjoining the upper edge of the rib central circumference, and a rib lower circumference adjoining the lower edge of the rib central circumference, and the rib central circumference is formed in a shape that is non-homothetic with that of the rib upper circumference or the rib lower circumference.

With such a configuration, the bottle strength and lateral rigidity can be further enhanced by that rib.

Preferably, the body portion as a whole has a shape approximately like a Japanese hand drum when it is viewed from the front.

With such a configuration, the waist portion is positioned almost in the vertical middle of the body portion. ,.

Preferably, any portion having the L1 value may be a circular portion having the maximum diameter of the body portion. With such a configuration, the L1 value is the maximum body diameter.

Preferably, a portion having the L1 value may be formed in the upper end of the upper body portion and in the lower end of the lower body portion.

With such a configuration, since the bottle has the portion with the maximum body diameter both in the upper and lower parts of the bottle, it.can be stably laid down. Moreover, the bottle so structured can be reliably conveyed in the manufacturing line, and is favorable for sale in vending machines.

Preferably, the upper body portion and the lower body portion are formed in a polygonal shape.

With such a configuration, since the portions adjoining the waist portion are formed in a polygonal shape, the bottle can be easily held at the waist portion.

Preferably, the plastic bottle includes a bottle bottom portion adjoining the lower end of the body portion. The outer wall of the bottle bottom portion is formed so that it narrows gradually or step-by-step downward along the central axis, to approximately the same size as the waist portion. With such a configuration, the bottle exterior design can be improved, and it is also possible to increase the bottom wall thickness, thereby improving the barrier properties of the bottle wall and its storage performance as a container.

In order to achieve the second object, the invention provides a plastic bottle that has a body portion formed in a generally polygonal shape. The body portion has a concave rib formed around its complete circumference. The rib has a rib central circumference, a rib upper circumference adjoining the upper edge of the rib central circumference, and a rib lower circumference adjoining the lower edge of the rib central circumference. The rib central circumference is formed in a shape that is non-homothetic with that of the rib upper circumference or the rib lower circumference.

With such a configuration, it is possible to reduce deformation of the rib upper and lower circumferences in the same way as the rib central circumference may be, and accordingly the bottle strength and lateral rigidity can be further improved by that rib.

Preferably, the shapes of the rib upper circumference and the rib lower circumference are the same as each other. Preferably, each corner of the shape of the rib central circumference is rounded, and each corner of the shape of the rib upper circumference or the rib lower circumference is chamfered.

With such a configuration, the rib is characterized by the rounded and/or chamfered corners. Preferably, no flexion point of the chamfered corner of the shape of the rib upper circumference or the rib lower circumference is located on a line connecting the central axis and the point on the rounded comer of the shape of the rib central circumference being the most distant from the central axis.

Preferably, the polygonal shape is approximately hexagonal. With such a configuration, the bottle can be more user-friendly, for example, in that the user's hands are less likely to slip on the bottle.

Preferably, the rib is formed in the vertical middle of the body portion. With such a configuration, lateral rigidity in the vertical middle of the body portion can be improved. Preferably, the body portion as a whole has a shape approximately like a

Japanese hand drum when it is viewed from the front, and a portion with the rib is narrowed the most.

With such a configuration, the lateral rigidity is improved in the portion with the rib, and the body portion can be easily gripped at this portion. Preferably, the body portion has a concave ring formed around its complete circumference at each of its upper and lower ends so that one ring is located above and below the rib. With such a configuration, since the body portion has one ring at each of its upper and lower ends, adequate lateral rigidity can be obtained in the upper, lower, and middle parts of the body portion.

In order to achieve the second object, the invention also provides a plastic bottle including: a mouth portion capable of receiving a detachable cap that attaches thereto; a shoulder portion adjoining the mouth portion; and a body portion adjoining the shoulder portion. ' The shoulder portion has a bump formed around its complete circumference. The bump has a vertical circumference, and a spherical-band-shape circumference adjoining the lower end of the vertical circumference and being curved in an outward direction from the central axis.

With such a configuration, the shoulder portion has the bump that is formed around the complete circumference, and thus the lateral rigidity is increased in the shoulder portion.

Preferably, the portion between the vertical circumference and the sphericai-band-shape circumference is rounded.

With such a configuration, the vertical circumference smoothly adjoins the spherical-band-shape circumference.

Preferably, the lower end of the spherical-band-shape circumference adjoins a portion having a maximum bottle diameter. - Preferably, the plastic bottle further includes a concave ring being formed around the complete circumference and defining the border between the shoulder portion and the body portion. A portion having the maximum bottle diameter is formed between and in contact with the bump and the ring.

With such a configuration, the lateral rigidity increases by the combination of the bump and the ring. Also, even if one of the bump or the ring is deformed, a certain level of lateral rigidity can be kept by the other.

In order to achieve the third object, the invention provides another plastic bottle that includes a bottle wall with at least one circular portion with a circular cross section. The bottle wall has at least one vacuum panel in the shape of a polygon with an odd number of angles, and the vacuum panel is formed to have a first side located close to the circular portion and along the circumference of the circular portion, and dented on at least the first side. With such a configuration, any vacuum created in the bottle can be accommodated by the vacuum panel with a polygonal shape and an odd number of angles, and accordingly, deformation of the bottle caused by any vacuum can be reduced. Furthermore, since the vacuum panel is formed in the shape of a polygon with an odd number of angles and is dented on its first side close to the circular portion, it also increases the lateral rigidity.

Here, a polygon with an odd number of angles is, for example, a triangle, pentagon, or heptagon.

Preferably, the first side of the vacuum panel is positioned 2 mm or more but less than 10 mm from the circular portion.

Preferably, a plurality of the vacuum panels is evenly spaced on the bottle wall along its circumference.

With such a configuration, since the vacuum panels are evenly spaced, any vacuum created in the bottle can be more appropriately accommodated. Here, any number of vacuum panels may be formed, and one example of that number is four. The number of vacuum panels may also be determined according to the bottle wall cross-sectional shape. For example, if the bottle wall is formed in a hexagonal shape, six vacuum panels may be formed.

Preferably, the circular portion has a concave rib formed around its complete circumference.

With such a configuration, lateral rigidity is improved by the vacuum panel and the rib. Moreover, if one of the vacuum panels or the rib is deformed, a certain level of lateral rigidity can be kept by the other.

Preferably, the vacuum panel depth varies gradually from the first side toward the apex the greatest distance from the first side, so that the panel depth is the greatest on the first side and decreases toward the apex.

With such a configuration, even if the vacuum-related deformation occurs to the bottle, the shape of the vacuum panel can be properly maintained.

Preferably, the panel depth at the apex the greatest distance from the first side is zero.

Preferably, the odd number of angles is three.

With such a configuration, the vacuum panel is formed in a triangular shape. In particular, by forming the vacuum panel in an isosceles triangular shape, the panel design can be less likely to be damaged even if vacuum-related deformation occurs in the bottle. .

Preferably, a perpendicular line drawn from the apex, the greatest distance from the first side to the first side bisects the first side.

Preferably, the two corners in contact with the first side are rounded by R5 or less. '

With such a configuration, it is possible to appropriately reduce deformation of the vacuum panel at the two corners. Preferably, the vacuum panels are formed above and below the circular portion. .

Preferably, the circular portion is formed at at least two places, being distant from each other along the central axis, and the vacuum panels are formed in relation to each circular portion. With such a configuration, any vacuum created in the bottle can be accommodated more effectively and lateral rigidity is further improved.

Brief Description of Drawings

Fig. 1 is a front view of a plastjc bottle according to an embodiment of the invention;

Fig. 2 is a side view of the plastic bottle in Fig. 1 ; Fig. 3 is a bottom view of the plastic bottle in Fig. 1; Fig. 4 is a cross-sectional view taken along the line IV-IV in Fig. 2; Fig. 5A is a diagram for explaining lateral rigidity in the waist of a comparative plastic bottle;

Fig.5B is a diagram for explaining lateral rigidity in the waist of the plastic bottle of Fig. 1 ;

Fig. 6 is a cross-sectional view taken along the line Vl-Vl of Fig. 2; Fig. 7 is an enlarged view of the shoulder of the plastic bottle in Fig. 1 ; and

Fig. 8 is an enlarged view of a vacuum panel in the plastic bottle in Fig. 1. Best Mode for Carrying Out the Invention

A plastic bottle according to a preferred embodiment of the invention is explained below with reference to the attached drawings, jn the below explanation, a plastic bottle is briefly outlined first regarding its roughly segmented portions, and each segment is then explained in detail. The plastic bottle is described below, taking as an example, a widely marketed 500ml plastic bottle.

As shown in Figs. 1 through 3, a plastic bottle 1 (hereinafter simply referred to as "bottle 1 ") is made of thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate. The bottle 1 is manufactured by various kinds of molding, such as blow molding, injection blow molding, or stretch blow molding (biaxial stretch blow molding). The manufactured empty bottle 1 is subjected to washing/sterilization involving hot-water disinfection, chloride disinfection, etc., and then is filled with liquid, which is the bottle content. The bottle 1 is filled with, for instance, a beverage, examples of which include various non-carbonated beverages, such as Japanese tea (green tea), oolong tea, tea, coffee, and fruit juice. The bottle 1 is filled with a non- carbonated beverage via a known sterile filling system, for example, hot-pack filling (at a relatively high temperature, e.g. 8O⁰C) or aseptic filling (at a room temperature, e.g. 15-35°C). A detachable cap (not shown in the drawing) attaches to the bottle 1 to close its dispensing opening.

Note that the bottle 1 is not limited to being filled with beverages, and the bottle 1 may be filled with foods such as Worcester sauce or Japanese cooking rice wine, and it may also be filled with carbonated beverages. The bottle 1 according to this embodiment is most suitable for being filled with non-carbonated beverages. The bottle 1 is not only easy to grip but also includes various characteristic structures for improving the ability to accommodate any vacuum created inside, and lateral rigidity, etc. Here, lateral rigidity generally means the strength against a load applied from outside in the lateral direction (radial direction) of the bottle 1.

The bottle 1 is made by integrally forming a mouth 2, shoulder 3, body 4 and bottom 5 so that each portion adjoins the next along the central axis (vertical axis) Y-Y from the_. top. These portions constitute a bottle wall 6 that enables a beverage to be stored inside the bottle 1. A panel section in the body portion 4 is defined as a portion between a pair of concave rings 7 and 8. The upper-side ring 7 forms the boundary between the body 4 and the shoulder 3, and the lower- side ring 8 forms the boundary between the body 4 and the bottom 5. Also, three types of triangular vacuum panels 10, 11 and 12 are formed on the bottle wall 6.

The mouth 2 is formed at the upper end of the bottle 1 , constituting the portion with the smallest diameter Of the bottle 1. The mouth 2 is open at its top end, and functions as an opening for supplying/dispensing a beverage to/from the inside. The mouth 2 has vent slots (screw portion) 21 formed to be capable of receiving a detachable cap that attaches thereto, and a flange portion 22 formed below the vent slots 21. The cap is twisted by users around the central axis Y-Y so that the cap moves between the open position and the closed position.

The bottom 5 is formed in the lower part of the bottle 1. The bottom 5 is as a whole formed to have a circular cross section, and the outer wall is formed so that it narrows gradually or step-by-step downward along the central axis Y-Y. In other words, the outer wall is formed so that the outside diameter of the circular cross section gradually decreases downwards. Furthermore, six triangular vacuum panels 12 are evenly spaced along the circumference on the outer wall. The base surface of the bottom 5 is dented upward to provide the bottle 1 with strength.

The body 4 as a whole has a shape approximately like a Japanese hand drum when it is viewed from the front (see especially Fig. 1). The vertical middle of the body 4 is narrowed relative to the remaining portion. The body 4 is composed of a waist 31 formed in the vertical middle; an upper body 32 formed so that it gradually enlarges and broadens from the waist 31 upward along the central axis Y-Y; and a lower body 33 formed so that it gradually enlarges and broadens from the waist 31 downward along the central axis Y-Y. With such a configuration, the outer wall of the body 4 is easy to grip. In order to make it much easier to grip the bottle, the distance from the center of gravity G in the bottle 1 to the waist 31 along the central axis Y-Y is 20mm or less. From its characteristic shape, the waist 31 can also be referred to li ^¬

as a narrowed portion or a throttle portion.

The upper body 32 and lower body 33 are shaped so that the outline gradually narrows toward the waist 31 , in other words, the distance from the central axis Y-Y to the outer wall gradually increases with distance from the waist portion 31. The upper body 32 may be formed so that it step-by-step enlarges and broadens upward, and the lower body 33 may be formed so that it step-by- step enlarges and broadens downward.

The body 4 is as a whole formed to have a polygonal cross-sectional shape. Preferably, the waist 31 , upper body 32 and lower body 33 are formed to have a polygonal cross-sectional shape with an even number of angles, and more preferably, the cross-sectional shape is approximately hexagonal, as in this embodiment. The reason that "approximately" is used above is that the cross section of the body 4 is basically an equilateral hexagon, but more specifically it is close to an equilateral dodecagon as each corner is chamfered or rounded. The waist 31 has a concave rib 35 that is formed around the complete circumference of the waist 31. A particular portion in this rib 35 is configured to have the minimum distance from the central axis Y-Y to the outer wall of the waist 31. By forming the rib 35 on the waist 3.1_. , the waist 31 has improved lateral rigidity compared to a waist with no rib. Also, with the below-explained characteristic shape, the rib 35 provides further improved lateral rigidity. This is explained next, referring to Figs. 1 , 4 and 5.

Fig. 4 is a cross-sectional view taken along the line IV-IV in Fig. 2, focusing on the cross section of the rib 35, and so the lower body 33 and other portions are not shown in Fig. 4. The outer wall of the rib 35 is constructed to be dented and the inner wall of the rib 35 is constructed to project to the hollow inside of the bottle 1. The outer wall of the rib 35 is composed of a rib central circumference 41 , a rib upper circumference 42, and a rib lower circumference 43.

One end of the rib upper circumference 42 adjoins the upper edge of the rib central circumference 41 , and the other end adjoins the lower end of the upper body 32. The rib upper circumference 42 inclines upward and outward relative to the cross-sectional face of the bottle.

One end of the rib lower circumference 43 adjoins the lower edge of the rib central circumference 41 , and the other end adjoins the upper end of the lower body 33. The rib lower circumference 42 inclines downward arid outward relative to the cross-sectional face of the bottle. The rib upper circumference 42 and the rib lower circumference 43 are formed in completely the same shape. Note that these two may be formed in different shapes.

The rib central circumference 41 is formed in a shape that is non- homothetic with that of the rib upper circumference 42 or the rib lower circumference 43. As stated before, the outline of the rib central circumference 41 is basically an equilateral hexagon, and each corner is rounded, for example, by R5. Meanwhile, the shapes of the rib upper circumference 42 and the rib lower circumference 43 are basically equilateral hexagons, and each corner is chamfered.

As shown in Fig. 5A, a rib central circumference 41' and a rib upper circumference 42' (or a rib lower circumference 43') of a comparative bottle are basically formed in the shape of an equilateral hexagon, each corner being chamfered, and their shapes are homothetic with each other. Consequently, on a particular corner, the straight line m connecting the flexion point 45' on the rib central circumference 41' and the flexion point 47' on the rib upper circumference 42' (or rib lower circumference 43') crosses the central axis Y-Y. In other words, in a rib 35' shown in Fig. 5A, the rib central circumference 41' is formed to be in an offset position with respect to the rib upper circumference 42' (or rib lower circumference 43').

As shown in Fig. 5B, six corners of the shape of the rib central circumference 41 are rounded. Thus, on a particular corner, the two flexion points 47 on the rib upper circumference 42 (or rib lower circumference 43) are not located on the straight line m connecting the central axis Y-Y and the point 45 on the rounded corner of the rib central circumference 41 being the most distant from the central axis Y-Y.

In other words, the straight line m connecting the central axis Y-Y and the point 45 crosses the rib upper circumference 42 (or rib lower circumference 43) between the two flexion points 47. So, in the rib 35 in the present embodiment, the rib central circumference 41 is not formed to be in an offset position with respect to the rib upper circumference 42 (or rib lower circumference 43), and by that rib 35, strength and lateral rigidity is further improved.

Referring back to Figs. 1 and 2, the upper body 32 and the lower body 33 are each formed to have a panel section, which is formed by connecting six panels that look like approximate trapezoids or flasks from the front, and six panels in the same shape but upside down, alternately along the circumference. The upper body 32 and the lower body 33 respectively have triangular vacuum panels 10 and 11 on every second panel formed as above.

A circular portion 50 having a ring 7 is formed at the upper end of the upper body 32, i.e., the upper side of the panel section. The ring 7 is formed around the complete circumference and in a concave shape with a vertical cross section of an inverted trapezoid, and its inner wall is formed to project toward the hollow inside of the bottle 1. The riηg 7 is formed in the vertical middle of the circular portion 50, and annular portions above and below the ring 7 in the circular portion 50 form maximum diameter portions 51 that have the maximum outside diameter of the bottle !

A circular portion 60 having a ring 8 is formed at the lower end of the lower body 33, i.e., the lower side of the panel section. The ring 8 is formed around the complete circumference and in a concave shape with a vertical cross section of an inverted trapezoid, and its inner wall is formed to project toward the hollow inside of the bottle 1. The ring 8 is formed in the vertical middle of the circular portion 60, and annular portions above and below the ring 8 in the circular portion 60 form maximum diameter portions 61 that have the maximum outside diameter of the bottle 1. The maximum diameter portions 51 and 61 have the same diameter.

When the bottle 1 is laid down, it is stably supported with the maximum diameter portions 51 and 61. Two rings 7 and 8 can also be called ring ribs, and increase the strength and lateral rigidity of the bottle 1 like the rib 35 in the waist 31. Instead of forming two rings 7 and 8 in an annular shape as stated above, they may be formed in a modified shape like the rib 35 in the waist 31 is. That modification is explained below with reference to Fig. 6.

As shown in Fig. 6, the outline of the ring 8 is an approximately equilateral hexagon. The reason that "approximately" is used here is that each side of the equilateral hexagon is formed in an arc shape and each corner is rounded, for example, by R4. Meanwhile, the outline of the maximum diameter portions 61 is circular. Since the outline of the ring 8 is non-homothetic with that of the maximum diameter portions 61 , the strength and lateral rigidity of this area is further improved. Note that the upper ring 7 and the circular portion 50 may be formed in this way too. Another modification is that the rings 7 and 8 are formed to have a circular outline, and the maximum diameter portions 51 and 61 are formed to have an approximately polygonal outline.

Next, one example regarding the sizes of the body 4 is briefly explained. In the body 4, the maximum distance L1 from the central axis Y-Y to the bottle outer wall is in the upper and lower maximum diameter portions 51 and 61 (see Figs. 2 and 6). Meanwhile, the distance L2 from the central axis Y-Y to a given point on the bottle outer wail of the waist 31 is set as shown in Fig. 4. That is, the distance L2 is the distance from the central axis Y-Y to a particular side of the approximately hexagonal outline that is the border between the rib lower circumference 43 and the lower body 33 (or the border between the rib upper circumference 42 and the upper body 32). ^' . For example, the distance L1 is between 30 mm and 35 mm inclusive, preferably 33.5 mm. The distance L2 is between 25 mm and 27 mm inclusive, preferably 25.805 mm. The L2/L1 ratio calculated based on the above is between 71% and 90% inclusive, preferably 77%.

By setting the relationship between the maximum distance L1 and the distance L2 as above, the body 4 is easy to grip at the waist 31. If the L2/L1 ratio is below 71%, the bottle volume becomes relatively small, and if the ratio is over 90%, the waist 31 is likely to be less easy to grip.

Next, the shoulder 3 is explained in detail with reference to Figs. 2 and 7. The shoulder 3 is formed to have a dome 71 adjoining the lower end of the mouth 2, and a bump 72 adjoining the lower end of the dome 72. The dome 71 is formed in a dome-like shape or an approximately truncated-cone-like shape so that it enlarges and broadens downward along the central axis Y-Y. The bump 72 is formed to have a vertical circumference 81 adjoining the lower end of the dome 71 ; and a spherical-band-shape circumference 82 adjoining the lower end of the circumference 81. Both circumferences 81 and 82 are formed around the complete circumference of the shoulder 3. The spherical-band-shape circumference 82 is curved in a radically outward direction relative to the circumference 81, and the lower end of the circumference 82 adjoins the upper one of the maximum diameter portions 51. That upper maximum diameter portion 51 substantially adjoins both the bump 72 and the ring 7, having a height of, for instance, less than 10 mm, preferably 3 mm. The portion between the vertical circumference 81 and the lower end of the dome 71 is rounded, for example, by R3. The portion between the vertical circumference 81 and the spherical-band-shape circumference 82 is rounded, for example, by R1.5.

By forming the bump 72 in the shoulder 3 as above- an effect like that provided by a ring rib can be achieved, resulting in the improvement of lateral rigidity in the shoulder 3. Also, by forming the bump 72 and the ring 7 in combination in the upper part of the bottle 1 , lateral rigidity can be further improved. Even if one of the bump 72 and the ring 7 is deformed, a certain level of lateral rigidity can be kept by the other.

Next, the vacuum panels 10, 11, and 12 are explained in detail with reference to Figs. 1 and 8. As explained before, the bottle wall 6 has triangular vacuum panels 10, 11 , and 12, six panels of each being evenly spaced around the circumference. With the vacuum panels 10, 11 , and 12, it is possible to accommodate any vacuum created in the bottle 1 after it is filled with beverages, and thus reduce deformation of the bottle 1. Also, by being formed in a triangular shape, the vacuum panels 10, 11 , and 12 can increase lateral rigidity like a ring rib does.

The first vacuum panels 10, second vacuum panels 11 , and third vacuum panels 12 are formed on the upper body 32, lower body 33, and the bottom 5 respectively. The second vacuum panels 11 are formed in a larger shape than the first and third vacuum panels 10 and 12. The number of the respective vacuum panels 10, 11 , and 12 is six in this embodiment, but the number may also be one. However, the number of the respective vacuum panels 10, 11 , and 12 is preferably more than one.

The vacuum panels 10, 11 , and 12 are all formed in a triangular shape when viewed from the front. Those panels 10, 11 , and 12 may be formed to look like, when viewed from the front, any type of triangular shape - including an equilateral triangular shape, and an isosceles triangular shape like in this embodiment. By being formed in an isosceles triangular shape, the vacuum panels 10, 11 , and 12 can keep their design, even if vacuum-related deformation occurs in the bottle 1.

Each of the vacuum panels 10, 11 , and 12 has one side 101 , 111 , or 121 positioned along the circumference and near the circular portion 50 or 60, Each of the sides 101 , 111 , and 121 is positioned, for example, 2 mm or more but less than 10 mm from their nearest maximum diameter portion 51 or 61 , along the direction of the central axis Y-Y.

More specifically, the side 101 of each first vacuum panel 10 is positioned immediately below the lower maximum diameter portion 51 in the upper circular portion 50. The side 111 of each second vacuum panel 11 is positioned immediately above the upper maximum diameter portion 61 in the lower circular portion 60. The side 121 of each third vacuum panel 12 is positioned immediately below the lower maximum diameter portion 61 in the lower circular portion 60.

The vacuum panels 10, 11 , and 12 are arranged vertically so that their, apexes 102, 112, and 122, which are the greatest distance from the respective sides 101 , 111 , and 121 , are located on the same vertical line. Since the vacuum panels 10, 11 , and 12 are formed in almost the same manner, the further details are explained below, with reference to the first vacuum panels 10.

As shown in Fig. 8, each vacuum panel 10 is formed by denting a part of the bottle wall 6, and has an uneven depth. Specifically, the depth of each vacuum panel 10 gradually varies from the side 101 toward the apex 102 which is at the greatest distance from the side 101. Therefore, the panel depth is the largest on the side 101 , decreases toward the apex 102, and is zero at the apex 102. In other words, the apex 102 is on the same plane as the other outer surfaces of the bottle wall 6. With this structure, the panel 10 can have improved ability to accommodate any vacuum created in the bottle 1. A modification may be made where the vacuum panel 10 is dented in its entirety.

In the vacuum panel 10, two corners 104 and 105 in contact with the side

101 are rounded, preferably by R5 or less. With such a configuration, deformation of the vacuum panel 10 at the two comers 104 and 105 can be reduced.

The three side faces 106, 107 and 108 that define the depth of the vacuum panel 10 incline to the inner side of the triangular panel face (bottom face) 109.

With this structure, molding the vacuum panel 10 becomes much easier, and it is also possible to. decrease the incidence of a chemical liquid accumulating in the panel 10 when the bottle 1 is subjected to chemical cleaning after it is manufactured.

While the vacuum panels 10, 11 , and 12 have been described as having an isosceles triangular outline above, the outline may also be described as a teardrop or water-drop shape. Also, the shape of the vacuum panels 10, 11 , and 12 is not limited to an isosceles triangle, and any polygon with an odd number of angles, for example, a pentagon or heptagon, may be used. All that is required for the vacuum panels 10, 11, and 12 is that the panels have one side along the circumference and that a perpendicular line drawn from the above side placed along the circumference to an apex at the utmost distance from that side bisects the side.

As explained above, a bottle 1 according to this embodiment has the waist

31 in the body 4, and the distance L2 in the waist 31 is defined to have the specific relationship with the relevant maximum distance L1 , and thus, the bottle 1 becomes easy to grip. Also, since the waist 31 is formed to have the polygonal cross-section, user-friendliness can be improved, for example, in helping a user grip the bottle when opening/closing the bottle cap.

Furthermore, the waist 31 has the rib 35 and the rib 35 is formed to have the cross section in the characteristic shape, and thus, lateral rigidity in this portion is improved. Also, two rings 7 and 8 as well as the bump 72 formed in the shoulder 3 also improve the lateral rigidity of the bottle 1, and the vacuum panels

10, 11 and 12 can also improve lateral rigidity of the bottle 1 too. In addition, the vacuum panels 10, 11 and 12 have the above-described characteristic shape, and thus have improved ability to accommodate any vacuum created in the bottle 1 , are capable of reducing the any vacuum-induced deformation in the bottle 1. Moreover, the above-described structure of the bottle wall 6 can enhance the aesthetically pleasing design of the bottle 1 , and can further make the bottle a suitable shape for handling in manufacturing lines and vending machines.

Claims

1. A plastic bottle, comprising: . . a mouth portion, a shoulder portion adjoining the mouth portion, and a body portion adjoining the shoulder portion, the body portion having: a waist portion including a portion whose distance from its central axis to its outer wall is the shortest in the body portion, and also having a specific cross sectional shape; an upper body portion formed so that it enlarges and broadens gradually or step-by-step from the waist portion upward along the central axis; and a lower body portion formed so that it enlarges and broadens gradually or step-by-step from the waist portion downward along the central axis, wherein the L2/L1 ratio is set to be between 71% and 90% inclusive, L1 being the longest distance from the central axis to the outer wall of the body portion, and L2 being the distance from the central axis to a given point on the outer wall at the waist portion.

2. A plastic bottle, comprising: a mouth portion, a shoulder portion adjoining the mouth portion, and a body portion adjoining the shoulder portion, the body portion having: a waist portion including a portion whose distance from its central axis to its outer wall is the shortest in the body portion, and also having a specific cross sectional shape; an upper body portion formed so that it enlarges and broadens gradually or step-by-step from the waist portion upward along the central axis; and a lower body portion formed so that it enlarges and broadens gradually or step-by-step from the waist portion downward along the central axis, wherein L1 , the longest distance from the central axis to the outer wall of the body portion, is set to be between 30 mm and 35 mm inclusive, and L2, the distance from the central axis to a given point on the outer wall at the waist portion, is set to be 25 mm and 27 mm inclusive. 3. The plastic bottle according to claim 1 or 2, wherein the waist portion is positioned 20 mm or less from the center of gravity of the plastic bottle.

4. The plastic bottle according to any of claims 1 to 3, wherein the specific cross sectional shape of the waist portion is a polygon.

5. The plastic bottle according to claim .4, wherein the polygon is an approximate hexagon. . 6. The plastic bottle according to claim 5, wherein each corner of the approximate hexagon is at least either chamfered or rounded.

7. The plastic bottle according to any of claims 4 to 6, wherein a concave rib is formed in the waist portion.

8. The plastic bottle according to claim 7, wherein the rib is formed around the complete circumference of the waist portion.

9. The plastic bottle according to claim 8, wherein the rib has a rib central circumference, a rib upper circumference adjoining the upper edge of the rib central circumference, and a rib lower circumference adjoining the lower edge of the rib central circumference, and wherein the rib central circumference is formed in a shape that is non- homothetic with that of the rib upper circumference or the rib lower circumference. iθ. The plastic bottle according to any of claims 1 to 9, wherein the body portion as a whole has a shape approximately like a Japanese hand drum when it is viewed from the front. 11. The plastic bottle according to any of claims 1 to 1 Q, wherein any portion having the L1 value is a circular portion having the maximum diameter of the body portion.

12. The plastic bottle according to any of claims 1 to 11 , wherein a portion having the L1 value is formed in the upper end of the upper body portion and in the lower end of the lower body portion.

13. The plastic bottle according to any of claims 1 to 12, wherein the upper body portion and the lower body portion are formed in a generally polygonal shape.

14. The plastic bottle according to any of claims 1 to 13, further comprising a bottle bottom portion adjoining the lower end of the body portion, wherein the outer wall of the bottle bottom portion is formed so that it narrows gradually or step-by-step downward along the central axis, to approximately the same size as the waist portion.

15. A plastic bottle, comprising: a body portion formed in a generally polygonal shape, the body portion having a concave rib formed around its complete circumference, ^' _. . . 21. ^■

the rib having a rib central circumference, a rib upper circumference adjoining the upper edge of the rib central circumference, and a rib lower circumference adjoining the lower edge of the rib central circumference, and the rib central circumference formed in a shape that is non-homothetic with that of the rib upper circumference or the rib lower circumference.

16. The plastic bottle according to claim 15, wherein the shapes of the rib upper circumference and the rib lower circumference are the same with each other.

17. The plastic bottle according to claim 15 or 16, wherein each corner of the shape of the rib central circumference is rounded, and wherein each corner of the shape of the rib upper circumference or the rib lower circumference is chamfered.

18. The plastic bottle according to claim 17, wherein no flexion point of the chamfered corner of the shape of the rib upper circumference or the rib lower circumference is located on a line connecting the central axis and a point on the rounded corner of the shape of the rib central circumference being the most distant from the central axis.

19. The plastic bottle according to any of claims 15 to 18, wherein the polygonal shape is approximately hexagonal.

20. The plastic bottle according to any of claims 15 to 19, wherein the rib is formed in the vertical middle of the body portion.

21. The plastic bottle according to any of claims 15 to 20, wherein the body portion as a whole has a shape approximately like a Japanese hand drum when it is viewed from the front and a portion with the rib. is narrowed the most.

22. The plastic bottle according to any of claims 15 to 21 , wherein the body portion has a concave ring formed around its complete circumference at each of its upper and lower ends so that one ring is located above and below the rib. 23. A plastic bottle, comprising: a mouth portion, a shoulder portion adjoining the mouth portion, and a body portion adjoining the shoulder portion, the shoulder portion having a bump formed around its complete circumference, and the bump having: a vertical circumference; and ^{• ■ ■ " •} .. ^{' "}22 ^{■ "}

a spherical-band^:shape circumference adjoining the lower end of the vertical circumference and being curved in an outward direction from the central axis. _. ^■ . - . , ^'•

24. The plastic bottle according, to claim 23, wherein the portion between the vertical circumference and the spherical-band-shape circumference is rounded.

25. The plastic bottle according to claim 24, wherein the lower end of the spherical-band-shape circumference adjoins a portion having the maximum bottle diameter. . . ;. .. . .^' . 26. The plastic bottle according to claim 25, further conhprising a concave ring being formed around the complete circumference and defining a border between the shoulder portion arid the body portion, wherein the portion having the maximum bottle diameter is formed between and in contact with the bump and the ring. 27. A plastic bottle, comprising: a bottle wall with at least one circular portion with a circular cross section, the bottle wall having at least one vacuum panel in the shape of a polygon with an odd number of angles, the vacuum panel being formed to have a first side located close to the circular portion and along the circumference, and the vacuum panel being dented on at least the first side. 28. The plastic bottle according to claim 27, wherein the first side of the vacuum panel is positioned 2 mm or more but less than 10 mm from the circular portion. 29. The plastic bottle according to claim 27 or 28, wherein a plurality of the vacuum panels is evenly spaced on the bottle wall along its circumference.

30. The plastic bottle according to any of claims 27 to 29, wherein the circular portion has a concave rib formed around its complete circumference.

31. The plastic bottle according to any of claims 27 to 30, wherein the vacuum panel depth gradually varies from the first side toward an apex the greatest distance from the first side, so that the panel depth is the greatest on the first side and decreases toward the apex.

32. The plastic bottle according to claim 31 , wherein the panel depth at the apex the greatest distance from the first side is zero. 33. The plastic bottle according to any of claims 27 to 32, wherein the odd number of angles is three. ; ^• 23 • ^{■ ■• ' • "}

34. The. plastic bottle according to any of claims 27 to 33, wherein a perpend icular line drawn from an apex the greatest distance from the first side to the first side bisects the first side. ^■ ,

35. The plastic bottle according to any of claims 27 to 34, wherein two corners in contact with the first side are rounded by R5 or less.

36. The plastic bottle according to any of claims 27 to 35, wherein the vacuum panels are formed above and below the circular portion.

37. The plastic bottle according to any of claims 27 to 36, wherein the circular portion is formed at at least two places, being distant from, each other along the central axis, and , wherein the vacuum panels are formed in relation to each circular portion.