MOLDED CONTAINER BASE

Abstract

A thermoplastic container including a body with a base, where the base includes a standing ring positioned concentric to the central axis, a base wall extending radially inwardly from the standing ring, and a plurality of dome-like impressions formed into the base wall, and where at least two of the dome-like impressions intersect with each other.

Description

FIELD OF THE INVENTION

The present application generally relates to molded containers and more specifically molded containers having improved base geometry.

BACKGROUND

Thermoplastic containers manufactured using blow molding or stretch blow molding include bases that are intended to support the pressure and weight of the material stored in the container. Such base walls must also include geometry that is applicable to the blow molding and stretch blow molding process.

SUMMARY

In some implementations, a container including a body at least partially defining an internal volume and a central axis, the body having a base including a standing ring positioned concentric to the central axis, a base wall extending radially inwardly from the standing ring, and a plurality of dome-like impressions formed into the base wall, and wherein at least two of the dome-like impressions intersect with each other.

Alternatively or additionally, in any combination, where the body also includes a sidewall and a threaded finish portion.

Alternatively or additionally, in any combination, where the body is monolithic.

Alternatively or additionally, in any combination, where the body is formed from a thermoplastic material.

Alternatively or additionally, in any combination, where each dome-like impression includes an effective dimension, and where the effective dimension of at least two of the dome-like impressions are different.

Alternatively or additionally, in any combination, where each dome-like impression defines a center point, and where each center point is spaced a respective radial offset distance from the central axis, and where the radial offset distance of at least two of the dome-like impressions are different.

Alternatively or additionally, in any combination, where each impression forms at least a portion of a spherical cap.

Alternatively or additionally, in any combination, where the base wall includes a radial center, and where the radial center of the base wall is offset axially relative to the standing ring.

Alternatively or additionally, in any combination, where at least two of the dome-like impressions form a strap defining a strap axis, and where the strap axis extends radially outwardly from the central axis.

Alternatively or additionally, in any combination, where each of the at least two of the dome-like impressions include an effective dimension, and where each effective dimension is unique.

Alternatively or additionally, in any combination, where the body is formed using one of a blow molding and stretch blow molding technique.

In another aspect, a container including a body at least partially defining an internal volume and a central axis, the body having a base including a standing ring positioned concentric to the central axis, a base wall extending radially inwardly from the standing ring, a first dome-like impression formed into the base wall, where the first dome-like impression includes a first effective dimension, a second dome-like impression formed into the base wall, where the second dome-like impression includes a second effective dimension, and where the first effective dimension is different than the second effective dimension.

Alternatively or additionally, in any combination, where the first dome-like impression forms at least a portion of a first spherical cap, and where the second dome-like impression forms at least a portion of a second spherical cap.

Alternatively or additionally, in any combination, where the difference in size of the first effective dimension and the second effective dimension is at least partially dependent on the difference in radial distance the first dome-like impression and the second dome-like impression.

In another aspect, a container including a body at least partially defining an internal volume and a central axis, the body having a base including a standing ring positioned concentric to the central axis, a base wall extending radially inwardly from the standing ring, and a first strap including a plurality of intersecting impressions, where each impression includes a corresponding central point, and where the first strap includes a first strap axis that passes through the central point of each impression included therein, and where the first strap axis is radially oriented relative to the central axis.

Alternatively or additionally, in any combination, where each impression at least partially forms a spherical cap.

Alternatively or additionally, in any combination, where the intersecting impressions includes a first impression and a second impression, where the first impression includes a first effective dimension and where the second impression includes a second effective dimension, and where the first effective dimension is different than the second effective dimension.

Alternatively or additionally, in any combination, where the first effective dimension is larger than the second effective dimension, and where the first impression is positioned closer to the central axis than the second impression.

Alternatively or additionally, in any combination, further including a second strap including a second plurality of intersecting impressions, where each impression of the second plurality of intersecting impressions includes a corresponding central point, and where the second strap includes a second strap axis that passes through the central point of each impression of the second plurality of intersecting impressions.

Alternatively or additionally, in any combination, where the first strap axis and the second strap axis define a strap angle therebetween, and where the strap angle is between 45 and 120 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom perspective view of a container.

FIG. 2 is a section view taken along line 2-2 of FIG. 1.

FIG. 3 is a detailed view of the base of FIG. 2.

FIG. 4 is a perspective view of one embodiment of a base for a container.

FIG. 5 is a bottom view of the base of FIG. 4.

FIG. 6 is a section view taken along line 6-6 of FIG. 5.

FIG. 7 is a perspective view of another embodiment of a base for a container.

FIG. 8 is a bottom view of the base of FIG. 7.

FIG. 9 is a section view taken along line 9-9 of FIG. 8.

FIG. 10 is a perspective view of another embodiment of a base for a container.

FIG. 11 is a bottom view of the base of FIG. 10.

FIG. 12 is a section view taken along line 12-12 of FIG. 11.

FIG. 13 is a perspective view of another embodiment of a base for a container.

FIG. 14 is a bottom view of the base of FIG. 13.

FIG. 15 is a section view taken along line 15-15 of FIG. 14.

FIG. 16 is a side view of a preform.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

FIGS. 1-2 illustrate a container 10, such as a bottle, made of a thermoplastic material such as polyethylene terephthalate (PET) and manufactured by blow molding or stretch blow molding with a heated preform (see FIG. 16). The container 10 includes a monolithic body 14 at least partially defining a storage volume 18 and a central axis 22. The body 14, in turn, includes a sidewall 26, a threaded finish portion 30 to which a conventional screw type plastic closure (not shown) can be attached, and a base 34 integrally formed with the sidewall 26 and positioned opposite the threaded finish portion 30.

As shown in FIGS. 1-6, the base 34 of the container 10 is sized and shaped to provide a stable foundation upon which the container 10 may be supported in a generally upright orientation on a support surface such as a tabletop and the like. The base 34 is also configured to have sufficient strength to withstand the pressures involved with the blowing and filling process, the internal pressures present within the storage volume 18 during storage and use, and minimize the amount of material used to form the base 34. In the illustrated embodiment, the base 34 includes a standing ring 38, a base wall 42 extending radially inwardly from the standing ring 38, a central element 46 formed into the base wall 42, and one or more impressions 50 formed into the base wall 42.

The standing ring 38 of the base 34 is annular in shape being positioned concentric with and generally normal to the central axis 22 of the container 10. As shown in FIG. 5, the standing ring 38 defines an outer ring diameter 54, generally defined as the diameter of the point of the standing ring 38 positioned furthest from the central axis 22 (see FIG. 6), and an inner ring diameter 58, generally defined as the diameter at the point of the standing ring 38 positioned closest to the central axis 22. Stated differently, the outer ring diameter 54 generally delineates where the base 34 of the container 10 begins curving upwardly to form the sidewall 26 (e.g., where the standing ring 38 curves away from the contact surface).

While the illustrated standing ring 38 is smooth forming a single continuous annular surface over an entire 360 degrees, it is understood that in other embodiments the standing ring 38 may be sub-divided into one or more segments using ridges and/or grooves formed therein (not shown).

The base wall 42 of the base 34 extends radially inwardly and axially upwardly from the standing ring 38 (e.g., toward the threaded portion 30) to enclose the bottom end of the container 10. The base wall 42 is generally domed or curved into the container 10 (e.g., extends into the storage volume 18) so that the outward surface 60 thereof forms an overall concave shape excluding any impressions 50 or central elements 46 formed therein. The curved nature of the base wall 42 provides additional strength and rigidity to the base 34 allowing the container 10 to withstand the pressures and forces present during use and the manufacturing process while also providing clearance so that the standing ring 38 may lie flat on the support surface.

In the illustrated embodiment, the base wall 42 forms an overall dome shape having a constant radius of curvature throughout (see FIGS. 3 and 6). However, it is understood that in other embodiments different overall shapes and contours may be present. For example, in some embodiments the base wall 42 may include multiple, nested annular portions that each include a different radius of curvature. In still other embodiments, additional shapes and contours may be present so long as the radial center 62 of the base wall 42 is positioned axially above (e.g., extending further into the storage volume 18) than the radial edge 66 of the base wall 42 so that the exterior thereof produces an overall general concave shape.

As shown in FIGS. 4-6, the base 34 further includes a central element 46 at the radial center 62 thereof. The central element 46 generally includes a geometric element formed into the base wall 42 at the radial center 62 thereof. The central element 46 is offset axially from the standing ring 38 to provide the overall dome-like shape of the base 34 as described above. In the illustrated embodiment, the central element 46 includes an annular groove 70 formed into the base wall 42 that is concentric with the central axis 22. More specifically, the annular groove 70 extends into the internal volume 18 of the container 10 such that the resulting groove 70 is open to the outside of the container (see FIG. 6).

The illustrated central element 46 is also sized such that the outer diameter thereof is less than the innermost radial position of any impressions 50 formed into the base wall 42. While the illustrated central member 46 is annular in shape, it is understood that in other embodiments different sizes and shapes of central member 46 may be formed into the base wall 42 proximate the central axis 22.

As shown in FIGS. 4-6, the base 34 also includes one or more impressions, depressions, protrusions, or bubbles 50 formed into the base wall 42 to provide rigidity and strength to the overall design in addition to influencing the flow of material during the container manufacturing process. The impressions 50, in turn, each include a corresponding center point or origin 78, and an effective diameter or dimension 82 that is generally representative of the impression's overall size. The impressions 50 are generally dome-like in shape forming a smooth curvilinear surface extending into or protruding out from the base wall 42. Such dome-like shapes may include, but are not limited to, a spherical cap, an elliptical dome, an ellipsoidal dome, an ovoidal dome, a spheroid cap, and the like. While the illustrated impressions 50 are shown extending outwardly from the base wall 42 (e.g., away from the storage volume 18), it is understood that in other embodiments all or a portion of the impressions 50 may also extend into the storage volume 18. The shape of the impressions 50 may also be truncated where they overlap or otherwise intersect adjacent impressions 50 and/or the central element 46.

In the illustrated embodiment, each impression 50 forms at least a portion of a spherical cap centered on the center point 78 such that the surface of the base wall 42 associated with a particular impression 50 is spaced half the effective diametric distance 82 from the corresponding center point 78. In some embodiments, the size and shape of each impression 50 may be truncated where it overlaps or otherwise intersects with adjacent impressions 50, the base wall 42, and/or the central element 46.

In still other embodiments, each impression 50 may include a concave or convex surface producing a circular opening 86 in the base wall 42 (e.g., the shape of the boundary between the impression 50 and the base wall 42; see FIG. 5). In such embodiments, the concave or convex surface may take on any curvilinear shape so long as the resulting opening 86 is circular in shape. Furthermore, the opening 86 of such impressions 50 may be truncated where it intersects with adjacent impressions 50, the base wall 42, and/or the central element 46. In still other embodiments, each impression 50 may include a concave or convex surface producing an elliptical or oval opening in the base wall 42. As stated above, such openings may be truncated where it intersects with adjacent impressions 50, the base wall 42, and/or the central element 46.

In the illustrated embodiment, each impression 50 also defines an impression depth 90, measured relative to the base wall 42 that is approximately equal to half the effective diameter 82. For example, in some embodiments the depth 90 may be between 35% to 50% of the effective diameter 82, between 35% to 45% of the effective diameter 82, and between 40% to 45% of the effective diameter 82. In other embodiments, each impression 50 may be set deeper or shallower than the effective diameter 82 as needed. In still other embodiments, each impression 50 of the base 34 may be set at the same relative depth (e.g., relative to its corresponding effective diameter 82). In still other embodiments, each impression 50 of the base 34 may be set at a unique depth 90 relative to its effective diameter 82. In still other embodiments, the depth 90 of each impression 50 may be proportional to the radial distance the impression 50 is spaced from the central axis 22. In such embodiments, the depth 90 may become shallower as the impression 50 is spaced further from the central axis 22.

The impressions 50 may also include one or more transition regions 94a, 94b extending along the boundaries thereof. Such transition regions 94a, 94b may be placed at the interface between the impression 50 and the adjacent base wall 42 (e.g., transition region 94a), or the interface of two intersecting impressions 50 (e.g., transition region 94b). In both instances, the transition region 94a, 94b generally includes a radius of curvature that is less than the effective diameter 82 of the adjacent impressions 50 themselves. Such transition regions 94a, 94b help to minimize or eliminate any potential high stress areas within the material of the container 10 by providing smooth transitions between the different surfaces the base 34.

As shown in FIG. 5, the base wall 42 includes a plurality of impressions 50 formed therein. In some embodiments, the impressions 50 are positioned on the base wall 42 such that at least two of the impressions 50 intersect and/or overlap with each other. In still other embodiments, the impressions 50 are sized such that at least two of the impressions 50 have different sized effective diameters 82. In still other embodiments, the impressions 50 are positioned on the base wall 42 such that the center points 78 of at least two impressions 50 are positioned at different radial distances from the central axis 22. In still other embodiments, the impressions 50 are sized such that the effective diameter 82 of each impression 50 is at least partially dependent upon the radial distance the corresponding impression's center point 78 is spaced from the central axis 22. In still other embodiments, the impressions 50 may be positioned to include any combination of the above features.

As shown in FIG. 5, the impressions 50 of the base 34 may be arranged in groups or straps 100 containing multiple, intersecting impressions 50. Specifically, each strap 100 includes a chain of multiple intersecting impressions 50 extending along a respective strap axis 103 that passes through the origin 78 of each impression 50 included therein. The resulting impressions 50 can then be ordered beginning with a lead impression 501 at one end of the strap axis 104 and then proceeding to count along the chain through the final impression 50, at the opposite end thereof.

In the illustrated embodiment, each strap 100 is oriented radially such that the respective strap axis 104 is linear in shape and extends radially outwardly relative to the central axis 22. The lead impression 501 is generally positioned closest to the central axis 22 with the chain counting up as the strap 100 extends radially outwardly therefrom. While the illustrated strap axis 104 is linear and oriented radially relative to the central axis 22, it is understood that in other embodiments a strap 100 may extend along a strap axis 104 that is not radially aligned with the central axis 22 and/or that is curvilinear in shape.

With reference to FIG. 5, the straps 100 are oriented on the base 34 such that each strap 100 forms a strap angle 108 relative to any adjacent straps 100. In the illustrated embodiment, the straps 100 are arranged equally about the central axis 22 such that all strap angles 108 are the same. More specifically, the strap angles 100 are between 45 degrees and 120 degrees, and 60 degrees and 90 degrees. In still other embodiments, the strap angles 100 are approximately 72 degrees.

In other embodiments each strap angle 100 may differ such that the straps 100 are not equally spaced about the central axis 22. In such embodiments, the strap angles 100 may be adjusted so that the resulting straps 100 are aligned with other features on the container 10 (e.g., the size and shape of the sidewall 26, grip features in the sidewall 26, the size and shape of the base 32, and the like.

The number of impressions 50 included in a given strap 100 may be at least partially dependent on the size of the container 10 itself. For example, the number of impressions 50 in a given strap 100 may be proportional to any one of the outer ring diameter 54, the inner ring diameter 58, the overall axial height of the container 10, the diameter of the container 10 at a pre-determined point along the sidewall 26, the length of the strap axis 104, and the like. In such embodiments, the number such impressions 50 may be a given fraction of the relevant dimension know as the impression ratio (R_IMP). In the illustrated embodiment, the impression ratio is 1:21 (E.g., one impression for every 21 mm of base diameter), however in other embodiments the impression ratio may include between 1:20-1:22; between 1:19-1:23; and between 1:18-1:24. Examples of different embodiments of container bases 34′, 34″, and 34′″ containing different numbers of impressions 50 per strap 100 is included in FIGS. 7-14.

In the illustrated embodiment, the number of impressions N₁ for a given strap 100 may be linked to the outer ring diameter D_ORD (measured in mm) through the following equation, and then rounding to the nearest whole number. In other embodiments, any of the other relevant container dimensions may be used in place of the outer ring diameter.

N ₁ =D _ORD/21

The size of each impression 50 within a given strap 100 may also be at least partially dependent on any combination of the size of the container 10, the relative location of the respective impression 50 within the strap axis 104 (e.g., the position of the impression 50 within the chain of intersecting impressions 50), the size of one or more of any adjacent impressions 50 within the strap 100, the relative location of the respective impression 50 on the base wall 42, and the like.

In instances where the size of a given impression 50 is dependent upon the size of the container 10, the impression 50 may further be proportional to any one of the outer ring diameter 54, the inner ring diameter 58, the overall axial height of the container 10, the diameter of the container 10 at a pre-determined point along the sidewall 26, the length of the strap axis 104, and the like. In instances where the size of a given impression 50 is dependent upon the relative location of the impression 50 along the strap axis 104, the impression may further be proportional to the distance the impression 50 is located from one of the ends of the strap axis 104 relative to the overall length of the strap axis 104. For example, if a particular strap 100 has an initial impression 501 of a given size at the first end thereof and the remaining impressions 50 are intended to reduce in size by 20% over the length of the strap axis 104, the size of each remaining impression 50 may be reduced in size proportional to how far away the impression 50 is from the initial impression 501 relative to the overall axis length (e.g., an impression positioned half-way down the strap axis 104 from the initial impression 501 would be reduced by 10% in size −50% of 20%, an impression positioned three-quarters of the way down the strap axis 104 from the initial impression 501 would be reduce by 15% in size −75% of 20%, and an impression positioned at the opposite end of the strap axis 104 would be reduce in size by 20%-100% of 20%). While the above example is a linear progression, other forms of progression such as exponential and the like may also be used in this way.

In still other embodiments, the size of each impression 50 may be proportional to its radial distance from the central axis 22. More specifically, the effective diameter 82 may grow or shrink relative to a datum by an amount at least partially reliant on the radial distance between the impression 50 and the axis 22. For example, the effective diameter 82 may shrink a given percentage (e.g., 1 to 2%) for a given distance of displacement relative to the central axis 22.

In the illustrated embodiment, the effective diameter 82 of the lead impression 501 (e.g., D₁) of each strap 100 is determined using the following equation with the input being the outer ring diameter 54 measured in mm (D_ORD) and the size ratio (R_SIZE). In other embodiments, any of the other relevant container dimensions may be used in place of the outer ring diameter 54. Furthermore, while the present size ratio (R_SIZE) is 0.125. It is understood that in other embodiments different size ratios may be used such as where R_SIZE is between 0.1 and 0.15, and between 0.1 and 0.2.

$D_a=D_{ORD}\times R_{\mathrm{SIZE}}$

With the size of the lead impression 501 calculated, the effective diameter of each subsequent impression 50N can be calculated based on the effective diameter of the previous impression 50N-1 and the reduction ratio (R_REDUC) using the following equation. While the present reduction ratio is 0.92, it is understood that in other embodiments different reduction ratios may be used such as where R_REDUC is between 0.9 and 0.95, and 0.85 and 0.975.

$D_N=D_{N-1}\times R_{REDUC}$

By way of example, if a base 34 has a base outer diameter (D_ORD) of 56 mm, the number and size of impressions included in each strap 100 is calculated as follows. First, each strap 100 will include three impressions based on the following:

$N_I=\frac{D_{ORD}}{21}=\frac{56\mathrm{mm}}{21}=2.6666=3$

With the number of impressions determined, the strap 100 will now include-starting from the radial center and counting radially outwardly-a first impression 501, a second impression 502, and a third impression 503 (see FIGS. 5 and 6). To calculate the diameter of each impression, the user first calculates the diameter D₁ of the lead impression 501.

$D_1=D_{ORD}\times 0.125=56\mathrm{mm}\times 0.125=7\mathrm{mm}$

With the initial impression 501 calculated, all subsequent impressions may then be calculated in turn:

$D_2=D_1\times 0.92=7\mathrm{mm}\times 0.92=6.5\mathrm{mm}$ $D_3=D_2\times 0.92=6.5\mathrm{mm}\times 0.92=6\mathrm{mm}$

As shown above, the impressions 50 are generally sized such that the effective diameter 82 gets proportionally smaller as the impressions 50 are positioned further from the central axis 22.

While the illustrated straps 100 are shown as elongated chains of impressions 50, each having a similar shape, it is understood that in other embodiments the overall shape of each impression 50 within a single strap 100 may vary. For example, in some straps 100 a combination of spherical and elliptical shaped impressions 50 may be present. Furthermore, in some embodiments the straps 100 may not just be limited to a single chain of impressions 50 along a single axis 104, but may rather split and/or merge to form parallel branches, each having a respective sub-branch of the strap axis 104.

To manufacture the container 10, the user first begins with a preform 200 including a full-sized threaded finish portion 30 and preform body 204. The preform 200 is then heated and placed in a mold corresponding to the above-described shape. Once in place, air is injected into the volume 18 of the preform body 204 causing the material of the preform body 204 to flow and stretch until it ultimately impinges upon the interior surface of the mold itself. While expanding, the shape and position of the impressions 50 and straps 100, described above, capture amorphous plastic that may not have stretched during the forming process. By doing so, the shape of the impressions 50 and straps 100 allow the material to remain rigid and provide support to the base shape even though portions of the captured plastic may not have been stretched. The above-described impressions 50 and straps 100 provide a base 34 that retains the strength of alternative base designs while using less material therein.

Claims

1. A container comprising: a body at least partially defining an internal volume and a central axis, the body having a base including: a standing ring positioned concentric to the central axis,a base wall extending radially inwardly from the standing ring, anda plurality of dome-like impressions formed into the base wall, and wherein at least two of the dome-like impressions intersect with each other.

2. The container of claim 1, wherein the body also includes a sidewall and a threaded finish portion.

3. The container of claim 1, wherein the body is monolithic.

4. The container of claim 1, wherein the body is formed from a thermoplastic material.

5. The container of claim 1, wherein each dome-like impression includes an effective dimension, and wherein the effective dimension of at least two of the dome-like impressions are different.

6. The container of claim 1, wherein each dome-like impression defines a center point, and wherein each center point is spaced a respective radial offset distance from the central axis, and wherein the radial offset distance of at least two of the dome-like impressions are different.

7. The container of claim 1, wherein each impression forms at least a portion of a spherical cap.

8. The container of claim 1, wherein the base wall includes a radial center, and wherein the radial center of the base wall is offset axially relative to the standing ring.

9. The container of claim 1, wherein at least two of the dome-like impressions form a strap defining a strap axis, and wherein the strap axis extends radially outwardly from the central axis.

10. The container of claim 9, wherein each of the at least two of the dome-like impressions include an effective dimension, and wherein each effective dimension is unique.

11. The container of claim 1, wherein the body is formed using one of a blow molding and stretch blow molding technique.

12. A container comprising: a body at least partially defining an internal volume and a central axis, the body having a base including: a standing ring positioned concentric to the central axis,a base wall extending radially inwardly from the standing ring,a first dome-like impression formed into the base wall, wherein the first dome-like impression includes a first effective dimension,a second dome-like impression formed into the base wall, wherein the second dome-like impression includes a second effective dimension, andwherein the first effective dimension is different than the second effective dimension.

13. The container of claim 12, wherein the first dome-like impression forms at least a portion of a first spherical cap, and wherein the second dome-like impression forms at least a portion of a second spherical cap.

14. The container of claim 12, wherein difference in size of the first effective dimension and the second effective dimension is at least partially dependent on the difference in radial distance between the first dome-like impression and the second dome-like impression.

15. A container comprising: a body at least partially defining an internal volume and a central axis, the body having a base including: a standing ring positioned concentric to the central axis,a base wall extending radially inwardly from the standing ring, anda first strap including a plurality of intersecting impressions, wherein each impression includes a corresponding central point, and wherein the first strap includes a first strap axis that passes through the central point of each impression included therein, and wherein the first strap axis is radially oriented relative to the central axis.

16. The container of claim 15, wherein each impression at least partially forms a spherical cap.

17. The container of claim 15, wherein the intersecting impressions include a first impression and a second impression, wherein the first impression includes a first effective dimension and wherein the second impression includes a second effective dimension, and wherein the first effective dimension is different than the second effective dimension.

18. The container of claim 17, wherein the first effective dimension is larger than the second effective dimension, and wherein the first impression is positioned closer to the central axis than the second impression.

19. The container of claim 15, further comprising a second strap including a second plurality of intersecting impressions, wherein each impression of the second plurality of intersecting impressions includes a corresponding central point, and wherein the second strap includes a second strap axis that passes through the central point of each impression of the second plurality of intersecting impressions.

20. The container of claim 19, wherein the first strap axis and the second strap axis define a strap angle therebetween, and wherein the strap angle is between 45 and 120 degrees.