WO2006093952A1

WO2006093952A1 - Container having textured grip and enhanced wall integrity

Info

Publication number: WO2006093952A1
Application number: PCT/US2006/007057
Authority: WO
Inventors: Thomas J. Hayes; Ashwin N. Shah; David K. Orr; Michael J. Maczuzak; Jose Victor Rodriguez; Luis Alberto Amador; Bernard H. Kirkland
Original assignee: Pactiv Corporation
Priority date: 2005-03-01
Filing date: 2006-03-01
Publication date: 2006-09-08
Also published as: CA2597017A1

Abstract

A nestable or stackable container having at least one recess (120) formed in the sidewall (114) of the container (100) to improve wall strength integrity. The surface of the recess further including texturing (124) to improve grippability such that the container can be grasped in any direction while providing improved tactile engagement. An anti-rotation element (142) is formed in the sidewall of the container and is configured to prevent rotation movement of the container when in a stacked or nested arrangement with a second container.

Description

CONTAINER HAVING TEXTURED GRIP AND ENHANCED WALL INTEGRITY

BACKGROUND OF THE INVENTION

Field of Invention

The present invention relates to an improved nestable container, such as for food or beverages. More particularly, the present invention is directed to a nestable container having enhanced wall integrity, increased rim strength, and improved tactile engagement.

Description of Related Art A variety of thermoplastic containers, such as containers for food and beverages, are well known in the art. Such thermoplastic containers are relatively inexpensive and disposable; and therefore are extremely popular. Such containers are often used at parties, picnics, gatherings, and other occasions where little or no clean-up is desired.

Although thermoplastic containers offer consumers many benefits, there are certain drawbacks affiliated with manufacture and use of thermoplastic containers. For instance, such a container can have a weak or flimsy side wall, as well as a weak rim. For instance, many consumers using thermoplastic drinking cups have experienced collapsing or crushing of the side wall when the container is grasped by the consumer. Similarly, the rim of such container can flex inward when a cup is gripped around the periphery of the rim. Conventional containers, which have side walls and rims that exhibit little crush resistance, therefore can cause messy spills and unwanted waste.

Another problem associated with thermoplastic containers is the lack of grippability due to condensation forming on the sidewall of the container, as well as the insufficient coefficient of friction of the material of the container. Conventional containers typically have a sidewall made of a smooth outer surface. Such a smooth outer surface can be very slippery when wet, for example, by condensation. Thus, it is difficult for a consumer to obtain a comfortable and sufficient grip on a container having a smooth outer surface, unless extra force is used to grip the container. However, as mentioned above, the typical container can have a sidewall that lacks sufficient crush resistance to withstand the extra gripping force required.

Numerous attempts have been made to develop and improved container having suitable crush resistance and improved tactile engagement without increased manufacturing costs. For example, U.S. Patent No. 6,554,154, the contents of which is incorporated herein by reference, discloses a container having a double set of annular ribs to provide a side wall container. Although suitable for its intended purpose, there remains a need for a container having the desired characteristics without the limitation of required ribs.

SUMMARY OF THE INVENTION

The purpose and advantages of the present invention will be set forth in and apparent from the description that follows, as well as will be learned by practice of the invention. Additional advantages of the invention will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof. Containers having enhanced wall integrity and improved gripping features are disclosed herein. Generally, each of the disclosed containers of the present invention has a base defining a closed bottom and a side wall extending upwardly from the base. The side wall has an outer surface and at least one recess formed in the outer surface. The recessed surface has a texture that is different than the surface texture of the outer surface of the side wall.

In accordance with one aspect of the invention, the at least one recess is defined by a boundary edge. In one preferred embodiment, the boundary edge has a curvilinear shape. In a further preferred embodiment, the boundary edge has a parabolic shape. However, the boundary edge can be configured to have alternative shapes, if desired. In one aspect of the invention, the container includes at least three recesses formed in the side wall. For example and not limitation, a preferred container has four recesses formed in the side wall. The at least three recesses can be disposed equally about the periphery of the side wall of the container. Each of the at least three recesses can be defined by a boundary edge having a similar curvilinear shape and size. However, it is to be understood that at least some of the recesses can have a shape or size that is different than another recess of the same container.

In one embodiment, the at least one recess forms a recessed surface having a texture that increases tactile engagement. Although a variety of textures can be used, a preferred texture has a multidirectional surface pattern capable of increasing tactile engagement generally in any direction, hi a preferred aspect of the invention, the multidirectional surface pattern includes an irregular surface pattern of protrusions and/or indentations, such as bumps, peaks and valleys. For example and not limitation, the texture can extend circumferentially, axially, or diagonally across the recessed surface. In accordance with a further preferred aspect of the invention, the texture extends entirely across the recessed surface.

In accordance with another aspect of the invention, the container is stackable with a second container of similar shape. In this aspect of the invention, each container includes an abutment portion to abut an adjacent container of similar shape, which is received in the mouth of the first container. The abutment portion is generally disposed proximate the base and includes a shoulder defined between the upstanding basewall and the side wall of the container. The shoulder defines a ledge along an inner surface of the container, such that either the bottom wall or the shoulder of an adjacent container, as desired, abuts the ledge of the first container to maintain a defined spacing therebetween.

In accordance with another aspect of the invention, the container includes at least one anti-rotation interlock element. The at least one anti-rotation interlock element is configured to interlock with the adjacent container, which is received in the mouth of a first container, and thus limit or inhibit the independent rotation of each container, if necessary or desired. In one embodiment, the at least one anti-rotation interlock element includes a plurality of depressions disposed about the periphery of the side wall of the container. In another embodiment, the at least one anti-rotation interlock element includes a plurality of protuberances disposed about the periphery of the sidewall of the container. Alternatively, however, the at least one anti-rotation interlock elements can be formed in the basewall of the container, if desired.

The plurality of depressions or the plurality of protuberances can be aligned with or disposed between adjacent recesses. At least one anti-rotation interlock element can have a height less than the height of the at least one recess. In this regard, and in a preferred embodiment, the container includes alternating recesses and depressions or protuberances along the periphery of the side wall, the height of each anti-rotation interlock element being less than the height of each adjacent recess.

In another aspect of the invention, the base of the container includes at least one indentation formed in the upstanding base wall along a periphery of the closed bottom, hi one aspect, the indentation is axially aligned with a depression, if provided. In another aspect of the invention, a stack of nestable containers is provided. The stack comprises a first container and a second container received within the first container. Each of the containers is substantially similar in shape and includes one or more of the same features described above. It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the invention claimed.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic perspective view of a first representative embodiment of a container in accordance with the present invention;

FIG. 2 is a schematic side view of the container of FIG. 1 in accordance with the present invention; FIG. 3 is a schematic top view of the container of FIG. 1 in accordance with the present invention;

FIG. 4 is a schematic bottom view of the container of FIG. 1 in accordance with the present invention;

FIG. 5 is schematic perspective view of further embodiment of a container in accordance with the present invention;

FIG. 6 is a schematic side view of the container of FIG. 5 in accordance with the present invention;

FIG. 7 is a schematic top view of the container of FIG. 5 in accordance with the present invention; FIG. 8 is a schematic bottom view of the container of FIG. 5 in accordance with the present invention;

FIG. 9 is a schematic cross section view of the container in accordance of FIG. 1 in accordance with the present invention;

FIG. 10 is a schematic cross section view of a first representative embodiment of a stack of nested containers in accordance with the present invention;

FIG. 1 IA is a schematic perspective view of a further representative embodiment of a container including at least one anti-rotation interlock element in accordance with the present invention;

FIG. 1 IB is a schematic perspective view of a further representative embodiment of a container including at least one anti-rotation interlock element in accordance with the present invention;

FIG. 12A is a schematic side view of a further representative embodiment of a container in accordance with the present invention; FIG. 12B is a schematic side view of a further representative embodiment of a container in accordance with the present invention;

FIG. 12C is a schematic side view of a further representative embodiment of a container in accordance with the present invention; FIG. 12D is a schematic side view of a further representative embodiment of a container in accordance with the present invention;

FIG. 12E is a schematic side view of a further representative embodiment of a container in accordance with the present invention;

FIG. 13 is a schematic perspective view of further representative embodiment of a container in accordance with the present invention;

FIG. 14 is a schematic bottom view of the container of FIG. 5 in accordance with the present invention;

FIG. 15 is a schematic top view of a container in accordance with the present invention; FIG. 16 is a schematic cross section view of the container of FIG. 1 IA in accordance with the present invention; and

FIG. 17 is a schematic perspective view of a further representative embodiment of a container in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the present preferred embodiments of the invention, an example of which is illustrated in the accompanying drawings.

The present invention provides for a container having enhanced wall strength and improved tactile engagement such that the container is configured to be capable of being gripped from substantially any direction. Such containers generally include but are not limited to beverage cups and food containers.

In accordance with the invention, a container is provided having a base defining a closed bottom, and a side wall extending upwardly from the base. The sidewall includes an outer surface and an inner surface. The closed bottom and the sidewall extending from the base define a receptacle space. The sidewall defines a mouth formed opposite the closed bottom. In accordance with the invention, the container further includes at least one recess having a recessed surface formed in the sidewall of the container. The recessed surface has a texture to increase tactile engagement therewith. In accordance with a particular aspect of the invention, the textured surface is configured to increase tactile engagement when grasped from substantially any direction.

For purpose of explanation and illustration, and not limitation, an exemplary embodiment of the container in accordance with the invention is shown in FIG. 1 and is designated by reference character 100. Additional features, aspects and embodiments of a container in accordance with the invention are provided in FIGS. 2-17, as will be described below.

For purposes of illustration and not limitation, as embodied herein and as depicted in FIG. 1, the container 100 has a base 112 defining a closed bottom 103, and a base wall 112a extending upwardly from the base. In one preferred embodiment, the base wall 112a has a reverse taper. That is, the basewall 112a has an upwardly and inwardly taper. A mouth 105 is formed opposite the closed bottom 103. The base 112 and sidewall 114 define a receptacle space capable of holding contents in the container 100.

The sidewall, embodied herein, is substantially cylindrical, and more preferably frustoconical, in shape, as shown generally in FIGS. 1 to 4. However, the sidewall can be configured to have a variety of other shapes, including but not limited to rectangular, hexagonal, or octagonal polyhedronal shapes. In one preferred embodiment, as depicted in FIGS. 2 and 4, the sidewall 114 has an upwardly and outwardly taper. Accordingly, the diameter of the mouth 105 is greater than the diameter of the closed bottom 103. Alternatively, however, the sidewall 114 can be configured such that the diameter of the mouth 105 can be substantially the same as closed bottom 103, if desired.

The dimensions of sidewall 114 depend on the particular application. For example and not limitation, if the container is an 18 ounce beverage cup, sidewall 114 can have a height approximately 4.5 inches, and a radius at the base of approximately 1 inch and a radius at the mouth of approximately 2 inches.

In accordance with a further aspect of the invention, container 100 further includes a first portion 130 and a second portion 132, as depicted in FIG. 2. First portion 130 includes at least a first section of sidewall 114a disposed proximate base 112 and extending upwardly to second portion 132 of container 100. The second portion 132 includes at least a second section of sidewall 114b disposed proximate mouth 105. In one preferred embodiment, sidewall 114a of first portion 130 has a shape different than sidewall 114b of second portion 132 of container 100.

For the purpose of illustration and not limitation, and as depicted in FIG. 2, sidewall 114a can have a substantially frustoconical shape, and sidewall 114b can have a substantially bowl-like shape. In this manner, sidewall 114a is proximate base 112 and extends upwardly at a constant taper or angle to a location 162 proximate second portion 132 of container 100. The portion of sidewall 114b has a radius that extends outwardly greater than the radius achieved by sidewall 114a. The greater radius of sidewall 114a thus can define in part a wider mouth 105 as well as a contoured surface ergonomically shaped for a user's hand. Preferably, the first portion extends between about 50% to about 75% the height of the sidewall. Although the shape of sidewall 114a and sidewall 114b are at least in part dictated by the radii of base 112 and mouth 105, respectively, sidewall 114a and sidewall 114b can have a variety of alternative shapes. Further, the shape of sidewall 114a and sidewall 114b can have substantially the same shape and radius to provide a continuous tapered or non- tapered container, if desired.

In accordance with a further aspect of the invention, the side wall 114 has at least one recess 120 formed in the side wall. The at least one recess is configured to increase crush resistance of the side wall 114. The term "crush resistance" as used herein refers to the resistance to inward deflection of the sidewall of the container. In particular, the wall integrity of the container 100 is increased by the recess, thereby reducing the occurrences of sidewall collapse when container 100 is grasped. In a preferred embodiment, container 100 can have a plurality of recesses. For example and not limitation, in one preferred embodiment, container 100 has four recesses. The at least one recess includes a recessed surface 121 defined by a boundary edge

122, as depicted in FIG. 1. hi one preferred embodiment, the boundary edge 122 has a curvilinear shape, and more preferably a continuously curved shape. Particularly, and in accordance with a preferred aspect of the invention, the boundary edge defines a parabola with an apex located opposite the base. Hence, the at least one recess has a bottom portion and a top portion. The width of the bottom portion of the at least one recess is greater than the width at the top portion of the at least one recess, such that the width decreases with increasing height along the container 100, and the top portion of the at least one recess forms an apex. In this manner, recess 120 also has a curvilinear shape. However, boundary edge 122 can be configured to have alternative shapes, for example and not limitation, polygonal shapes, as deemed suitable or desirable for the intended purpose.

In further accordance with an additional aspect of the invention, the boundary edge 122 defines an edge surface 123 extending between the recessed surface 121 and the sidewall 114. As depicted herein, the edge surface is parabolic in shape and angled relative to the recessed surface and the sidewall, respectively. For the purpose of illustration and not limitation, as embodied herein and depicted in FIG. 2, the at least one recess 120 has a height generally perpendicular to closed bottom 103 that is between about 50% to about 80% of a height of sidewall 114. In one preferred embodiment, the at least one recess extends upwardly from base 112 and is formed in the first portion 130 of sidewall 114. Further preferred, at least a portion of boundary edge 122 such as the edge surface can extend to at least the second portion 132 of sidewall 114 of container 100, as depicted in FIG. 2.

As described further below, and in accordance with another aspect of the invention, the base 112 can include a base wall 112a extending upwardly from the closed bottom. The base wall 112a and the sidewall 114 define an annular shoulder 146 therebetween. As embodied herein, and as depicted in FIG. 2, the at least one recess can extend from the annular shoulder 146 upwardly of sidewall 114. Alternatively, the at least one recess 120 can extend from closed bottom 103 of container 100 upwardly along a height of sidewall 114, if desired or if no annular shoulder is provided. In accordance with yet another aspect of the invention, the recessed surface can define a generally partial cylindrical, frustoconical, or even-bowl shaped surface configuration, as desired. For example, and as depicted in FIG. 2, the sidewall can extend upwardly at a first angle to define a frustoconical surface configuration, and the recessed surface of the at least one recess can extend upwardly at a second different angle to define a portion of a second frustoconical surface configuration. By providing different angles or configurations therebetween the at least one recess can be further defined from the sidewall and the strength of the sidewall can be further enhanced. In yet another alternative, the sidewall and the at least one recess can extend upwardly at substantially the same angle in a spaced relationship. In this manner, the at least one recess can be further defined from the sidewall by providing a step in the sidewall.

In accordance with a further aspect of the invention, the recessed surface of the at least one recess is configured for increased tactile engagement by a user. Particularly, and as embodied herein, the recessed surface 121 is provided with a texture 124 to increase tactile engagement. A variety of textures can be incorporated, either individually or in combination. Such textures include ribs, protrusions and indentations. In accordance with a preferred aspect of the invention, the textured surface is configured to increase tactile engagement when gripped from virtually any direction. The textured surface therefore is preferably defined or formed by a multidirectional surface pattern of protrusions and/or indentations, such as but not limited to a regular or irregular pattern of protrusions defining peaks and valleys. In a preferred embodiment, the multidirectional surface pattern includes about 10 to 900 protrusions or peaks per square inch of the textured surface, and more preferably about 100 to 700 protrusions or peaks per square inch of the textured surface.

In accordance with the invention, the multidirectional surface patterns can extend circumferentially, axially, or diagonally across the recessed surface 121. In accordance with yet another aspect of the invention, the recessed surface can include a combination of ribs and a multidirectional surface pattern texture. For example and not limitation, the recessed surface can include ribs or ridges having a textured surface thereon or therebetween. The ribs or ridges can be arranged in any suitable pattern, for example and not limitation, the ribs can form a linear array or alternatively form a circular pattern, with the multidirectional surface pattern extending circumferentially axially or diagonally.

The multidirectional surface pattern enhances tactile engagement and improves grippability of the container. For the purpose of illustration and not limitation, the protrusions provide greater surface area for tactile engagement by a user, and the indentations can provide a plurality of troughs to house and wick away condensation. In this manner, the multidirectional surface pattern increases tactile engagement by reducing slippage when a container in accordance with the present invention has condensation formation on its outer surface. Further, the greater surface area and/or coefficient of friction provided by the multidirectional surface pattern enhances tactile engagement and improves grippability of a container having a dry surface. Additionally, because the texture is a multidirectional pattern of, for example, bumps, protrusions, dimples, and indentations, or grid-like cross hatching, the container is configured for increased tactile engagement regardless of the direction in which it is grasped. That is, a discrete pattern of ribs or ridges generally provides tactile engagement in a single direction. In this regard, the particular direction or orientation of the ribs or ridges on the surface of the container dictate the direction in which the container should be grasped if improved grippability is to be attained. By contrast, the use of a multidirectional pattern in accordance with the present invention provides a surface on the container for increased tactile engagement despite the orientation of the container when grasped. Further, the texture in accordance with the present invention can be provided with an increased coefficient of friction when measured in a variety of directions, unlike a discrete pattern that may only provide an increased coefficient of friction in a limited number of directions. The greater coefficient of friction of the multidirectional pattern of protrusions and/or indentations enhances tactile engagement and grippability when container 100 is grasped by a consumer. A variety of multidirectional patterns are suitable for the present invention. For example, the multidirectional pattern can be provided in the form of a regular pattern of offset bumps or intersecting raised cross hatching. Alternatively, an irregular pattern of bumps or protrusions can be used, as preferred and embodied herein. Additionally, the texture in accordance with this aspect of present invention can provide the advantage of eliminating at least one step in the manufacturing process, so as to provide a more efficient and less costly procedure. By providing the texture with an irregular pattern, for example, imperfections otherwise visible with a regular or symmetrical pattern are not relevant. That is, each irregular pattern is unique, and not limited by symmetry. In this regard, the manufacturing process to form a container 100 in accordance with the present invention does not require an additional quality control inspection to ensure that each container produced on the assembly line includes a texture having an identical pattern. In contrast, the manufacturing process to form containers having a regular pattern, such as a pattern including ribs or ridges, generally requires a step in the process for visual inspection of each container to ensure that the regular pattern is maintained for each container. Other advantages of providing a container having a texture in accordance with the present invention is that the texturing eliminates blemishes from the moldings, so as to conceal heat-check marks, sink marks, and flow marks.

In accordance with another aspect of the invention, the texture is coextensive with the entire recessed surface. In this manner, and unlike a discrete or isolated raised rib, an increased tactile engagement can be accomplished anywhere within the boundary of the recessed surface. Such an arrangement increases the predictability in grasping the container with the recesses provided. The container can further include additional suitable surface treatments as known in the art. A variety of techniques can be used for forming the texture on the recessed surface in accordance with the invention. For the purpose of illustration and not limitation, container 100 can be provided having texture 124 on a surface of recess 120 by a textured mold. In this manner, a metal mold, for example but not limitation, an aluminum mold body can be configured with a multidirectional, and preferably, an irregular pattern in accordance with the present invention. For example, but not limitation, the metal mold can be acid etched to define a texture pattern. In this regard, an acid can be applied to a portion of the metal mold to degrade the metal material in a particular or desired pattern. Alternatively, a hobbing process can be used, in which a master having a particular texture is applied with force to a metal mold, such as for example an aluminum mold. The particular pattern on the master displaces portions of the metal mold to create the desired texture. The textured mold is then used to fabricate the container in accordance with the present invention. In a preferred embodiment, the mold is configured to provide an irregular pattern of protrusions, similar to that depicted in FIGS. 1 and 5, to define a depth of approximately 0.008" and a draft angle of approximately 12° minimum. Such textured molds can be formed and provided by, for example, a variety of texturing suppliers known in the art.

In accordance with a further aspect of the invention, the container includes an abutment portion configured to abut a second container of similar shape received in a nested relationship within the mouth of the container. The abutment portion 140 is generally disposed proximate the base 112. In accordance with one aspect of the invention, and as previously described, base 112 can include an upstanding base wall 112a extending from the closed bottom 103. As shown in FIG. 2, abutment portion 140 includes shoulder 146 defined between upstanding base wall 112a and the sidewall 114. The shoulder defines a ledge on the inner surface of the container, as depicted in FIG. 3 and in the cross section in FIG. 9. The ledge can be configured to abut the bottom 103 of an adjacent container received within the first container so as to maintain a spaced relationship between the two containers as depicted in FIG. 10. Alternatively, the ledge can be configured to abut the shoulder of an adjacent container as described with regard to the embodiments of FIG. 5 below.

In a further aspect of the invention, the container 100 further includes at least one anti-rotation interlock element 142 to prevent relative rotation between adjacent containers received in a nested relationship. The at least one anti-rotation interlock element is configured to limit or inhibit rotational movement of a container when engaged with a second container of similar shape. In this regard, the at least one anti-rotation interlock element 142 is configured to interlock with another anti-rotation interlock element disposed on an adjacent container of similar shape when received in the mouth of the first container. The at least one anti-rotation interlock element 142 can include at least one depression 142' (as shown for example in FIGS. 1 IA, 1 IB, 12A and 12B), at least one protuberance 142" (as shown for example in FIGS. 12C, 12D, and 12E) formed in the sidewall 114 of the container, or a combination of at least one depression 142' and at least one protuberances 142" as shown for example in FIG. 17.

Alternatively, the at least one recess 120 can be configured to prevent relative rotation between adjacent containers received in a nested relationship. In this regard, no additional anti-rotation interlock elements are required. In one preferred embodiment, the container includes four recesses configured to interlock with an adjacent container and limit or independent rotation of each container.

The at least one anti-rotation interlock element can be disposed in the first portion 130 of the container or the second portion 132 of the container, as depicted in FIGS. 12B and 12 A, respectively. Alternatively, as embodied in FIG. 1 IA, the at least one anti-rotation interlock element can be disposed between the first and second portions of the container such as to span the first portion 130 and the second portion 132 of the container 100. If desired, the at least one anti-rotation interlock element can be disposed in the base 112 of the container 100, as depicted in FIG. 5. Particularly, the at least one anti-rotation interlock element 142 can be disposed proximate base 112 as illustrated in FIGS. 1 and 2, proximate annular lip 150 as illustrated in FIG. 1 IB, or formed in the base wall 112a as illustrated in FIG. 5.

Additionally, the at least one anti-rotation interlock element can be disposed such that it is axially aligned with at least one recess, axially misaligned with at least one recess, or can be disposed such the at least one anti-rotation interlock element is adjacent a recess 120 as illustrated in FIGS. 1 IB, 12A, and 1 IA, respectively.

In a preferred embodiment, the at least one anti-rotation interlock element includes a plurality of anti-rotation interlock elements disposed about a periphery of the container, which can be disposed at regular or irregular angular intervals about the periphery of the container. In this regard, the plurality of anti-rotation interlock elements can be disposed about the periphery of the container such that at least a first anti-rotation interlock element formed in the sidewall at a first location is diametrically opposed to a second anti-rotation interlock element formed in the sidewall at a second location, if desired. For example, and as embodied herein as depicted in FIG. 3, the at least one anti-rotation interlock element 142 includes a plurality of depressions 142' formed in the side wall proximate the base 112.

Particularly, and as embodied herein, the at least one depression is disposed in the sidewall above the annular shoulder. As shown in FIG. 4, the plurality of depressions are disposed about the periphery of the side wall 114. For further example and as illustrated in FIG. 1 IA, the at least one depression 142' can be formed in the sidewall between two adjacent recesses 120. Alternatively, however, the at least one depression 142' can be configured to be in axial alignment with at least one recess 120.

The at least one anti-rotation interlock element is configured to define a protruding shelf. In particular, the at least one depression 142' extends inwardly to define or form a protruding shelf 144' extending from an inner surface of sidewall 114 into the receptacle of container 10O₃ as best can be viewed from FIG. 3 and a cross section in FIG. 9. The at least one protuberance extends outwardly to define or form a protruding shelf 144" extending from an outer surface of sidewall 114 to the exterior of the container 100, as depicted in FIGS. 12C-E. In this manner, the at least one protuberance is formed in sidewall 114 of container 100 such that a cavity is formed in the inner surface of the sidewall 114 and a corresponding protrusion is formed in the outer surface of sidewall 114 thereby defining the protruding shelf 144" as illustrated in FIG. 12C.

Further, the at least one recess 120 can be configured to interlock with an adjacent container received in the mouth of a first container and limit or inhibit relative rotation between the containers. In this regard, the boundary edge 123 can be configured to define or form a protruding shelf extending from the inner surface of sidewall 114 into the receptacle of the container, as illustrated in FIG. 15.

The protruding shelf 144', 144" formed or defined by the at least one anti-rotation interlock element (or by the recess as the case may be) includes a depth 170 measured from a phantom extension 188 of the circumference of the container, as illustrated in FIG. 14. Phantom extension 188 extends along a horizontal cross section of container 100. As illustrated in FIG. 16, the protruding shelf 144' , 144" defines a draft angle 184 with respect to vertical axis 186 of the container. Vertical axis 186 is a central axis which is preferably perpendicular with the bottom 103 of container 100. Draft angle 184 is measured from the axis 186 to the protruding shelf 144' at the apex of the protruding shelf. In a preferred embodiment, draft angle 184 is about 5° to about 85° degrees, and preferably about 20° to 30°. As further illustrated in FIG. 16, a second draft angle 180 is defined by the protruding shelf 144' and the sidewall 114 of container 100. In a preferred embodiment, the depth 170 as shown in FIG. 14 and the draft angle 180 as shown in FIG. 16 vary across a height of the at least one anti-rotation interlock element 142, as discussed below. Further draft angle 182 is defined between central axis 186 and the sidewall 114 of container 100, as illustrated in FIG. 16. In a preferred embodiment, draft angle 182 is at least about 0°, up to about 30° and most preferably about 5° to 15°.

In particular, and as discussed above, the at least one depression 142' as illustrated in FIGS. 14 and 16(or at least one recess) includes a protruding shelf having a varied depth 170 and draft angle 180 which increases with the height of the depression. Conversely, the at least one protuberance includes a protruding shelf having a varied depth and draft angle which decreases with an increase in height of the protuberance. In a preferred embodiment, the at least one anti-rotation element, i.e., the at least one depression or the at least one protuberance, includes a protruding shelf having a depth that varies from approximately 0.045 inch to approximately 0.082 inch, and draft angle 180 can vary from approximately 4° to approximately 90°. In this manner, the at least one depression can have a continuously increasing depth along the height of the depression and the at least one protuberance can have a continuously decreasing depth along the height of the protuberance. Alternatively, the at least one depression (or the at least one recess) or the at least one protuberance can be configured to include a step to define an adjacent area of increased or decreased depth, respectively. As will be recognized by one skilled in the art, the depth 170 of the anti- rotation interlock element and the draft angles 182 and 184 can be optimized for ease of manufacturing, e.g., removal of container from mold, and for desired stacking or nesting height of a stack of containers. In a preferred embodiment, the portion of the depression that is closest to the central axis 186 is disposed at the bottom of the depression.

The protruding shelf of the anti-rotation interlock element 142 is capable of engaging a corresponding anti-rotation interlock element of a second container of similar shape. The engagement between the anti-rotation interlock elements or recesses of adjacent containers thereby maintains proper alignment for stacking and prevents rotation therebetween. Further, the anti-rotation interlock element can be configured to maintain an axial spaced relationship between the sidewall 114 of one container and a sidewall of a second container when in a stacked or nested orientation, if desired. In one embodiment, as schematically shown in FIG. 4, the container includes at least one recess and at least one depression. The at least one depression has a height less than the height of the at least one recess. Although the dimensions of the at least one depression can depend on the particular application. For example and not limitation, for a beverage cup, the at least one depression can have a height of approximately 0.4 inch and a depth of approximately 0.045 inch to about 0.082 inch.

In one embodiment, the at least one depression is formed in the base wall 112a of base 112 below the annular shoulder 146, as depicted in FIG. 5. As depicted in FIG. 6, and can be best viewed in FIG. 7, the at least one depression extends radially inward beyond the ledge formed by the annular shoulder. In this embodiment, the base 112 of the container is configured to have a smaller diameter than the internal diameter provided by the ledge formed by the annular shoulder. In this regard, the shoulder of an adjacent container that is inserted into the mouth of a first container will abut the ledge formed by the shoulder of the first container. The depression 142 therefore defines a shelf for engagement by a corresponding depression in an adjacent container that is inserted into the mouth of the first container to establish the desired anti-rotation interlock and /or spacing features of the engagement portion. The ledge formed by the annular shoulder also can be configured to maintain a spaced relationship between the sidewall of the container and a sidewall of a second container when in a stacked orientation. Alternatively, the container can be configured without an annular shoulder.

The at least one anti-rotation interlock element in accordance with the invention can be configured to have a variety of shapes. For example and not limitation, as described above, the at least one anti-rotation element can be configured to have a curvilinear shape, as depicted in FIG.2 Additionally or alternatively, the at least one anti-rotation interlock element can be configured to have other suitable shapes such as polygonal or polyhedronal shapes. For the purpose of illustration and not limitation, the at least one anti-rotation interlock element can be formed in suitable shapes such as a diamond, square, rectangular, triangular or other polygonal shape. Further, the at least one anti-rotation interlock element can have a linear shape or can be configured to represent a logo and can include alphanumeric characters or variations thereof, if desired.

Further, the at least one anti-rotation interlock element can be configured to include a finger grip 172 for ergonomic comfort for the user, as depicted in FIG. 13. In this regard, the finger grip can be an indent ergonomically configured to receive a finger, for example the thumb, of the user. Alternatively, the finger grip can be a raised surface. If desired, the finger grip includes a textured surface for increased grippability.

Further, the base 112 can include indentation 116, which can best be seen in FIG. 4, formed within the base wall 112a along a periphery of the closed bottom 103. In one embodiment, indentation 116 is axially aligned with a corresponding depression 142, although alternative arrangements can be provided. Further in accordance with the invention, the mouth 105 of container 100 includes an annular lip 150. In a preferred embodiment, the lip has a substantially planar top surface 152, and a flange 154 angle laterally from the substantially planar top surface 152, as depicted in FIG. 1. The flange 154 is folded at least partially under the substantially planar top surface 152 such that the flange is configured at an angle of approximately 25° and greater, for example and not limitation 45°, relative to the substantially planar top surface 152. The configuration of the annular lip therefore can have a substantially triangular configuration. In one preferred embodiment, the unique annular lip configuration can be formed by known lip forming techniques. In this manner, a lip forming machine is used to form a lip on the rim of the thermoformed containers, such as disposable cups, food packages, and the like. A stack of nested containers is fed into a conveyor, which directs the containers into a space between a set of rotating feed rollers. The feed rollers engage the rim of the containers and rotate the stack of nested containers. The containers are thereby advanced into the interior of a heating oven having a heating source, such as for example a calrod. The stack of nested containers are heated in the oven, and then are directed to a set of rotating forming screws. The forming screws engage the heated rims of the containers and progressively fold a portion of the rim downward to create the triangular lip configuration on the rim of each container. However, the annular lip can also have other configurations, such as but not limited to a rounded, rectangular, or square configuration, or can otherwise be folded or rolled in a conventional manner.

The dimensions of the annular lip, including the substantially planar top surface 152, and flange 154, as well as the particular angle at which the flange is rolled will depend upon the intended application of the container. For example and not limitation, for a beverage container, such as a cup, the planar top surface has a length of approximately 0.15 inch, the flange 152 has a length of approximately 0.10 inch, and the flange is preferably at an angle of approximately 28° in relation to the planar top surface 152.

As shown in FIG. 2, sidewall 114 can be configured to include at least one ridge 160 disposed circumferentially about a surface of the sidewall, if desired. For example and not limitation, ridge 160 is disposed proximate to annular lip 150. Alternatively, however, ridge 160 can be disposed at other locations, if desired. Additionally, a plurality of ridges can be disposed circumferentially about the sidewall 114 of container 100.

Particularly, an 18 oz. disposable beverage container in accordance with the present invention, and having a configuration similar to that of FIGS. 1 to 4, was formed with the following relevant dimensions: height 4.75 in.; base diameter 2.33 in.; mouth diameter 4.00 in.; number of recesses 4; recess height including boundary edge 3.10 in.; and a formed lip including a top planar surface having a length of 0.15 in., a flange having a length of 0.15 in., the flange forming an angle of 28° relative to the top planar surface.

As mentioned above, the container in accordance with the present invention has improved sidewall crush resistance or improved wall strength integrity, as well as improved lip strength. To demonstrate the improvement in strength of a container in accordance with the present invention a standard comparison deflection test was performed on the sidewall and the lip of a container in accordance with the present invention and of a commercially available container of generally similar size. Each container sample tested was an 18 oz. beverage cup. The results of the comparative deflection test illustrated that the container in accordance with the present invention has about an 8% increase in sidewall strength as compared to the standard commercially available container. The results also illustrated that the container in accordance with the present invention has about a 31% increase in lip strength as compared to the standard commercially available container. Thus, the results of the comparative deflection analysis illustrated the improvement in structural integrity of both the sidewall and the lip achieved by the container in accordance with the present invention.

In accordance with another aspect of the invention, a stack of nestable containers 110 is provided. The stack of nestable containers includes a first container 100 and an adjacent container 101 received within the first container. Each stackable container has a substantially similar shape as described above.

For the purpose of illustration and not limitation, and as depicted in FIG. 10, in a preferred embodiment, a second container 100' is received within the mouth 105 of the first container 100 such that the body of the second container extends downwardly through the mouth and into the receptacle of the first container. As discussed above, and as depicted in FIG. 10, the annular shoulder 146 of the first container 100 provides a ledge along an inner surface of the first container, such that when the second container 100' is disposed within the mouth 105 of the first container and extends downwardly through its receptacle, the bottom of the second container 100' abut the ledge on the inner surface of the first container 100 to maintain a defined spacing therebetween. Alternatively, and as previously noted with regard to the embodiment of FIG. 5, the bottom can be dimensioned so as to be smaller than the cross dimension of the ledge. In this manner, the bottom of the second container will be disposed within the volume defined by the upstanding base wall of the first container, and the shoulder of the second container will abut the ledge of the first container.

In accordance with one preferred embodiment, as depicted in FIG. 10, the ridge 160 disposed circumferentially about the surface of the sidewall 114 of the first container 100 engages at least a portion of the annular lip 150 of the adjacent container 101 when in a stacked orientation.

In accordance with a further aspect of the invention, the engaging portion 140 of the first container includes at least one depression to engage a corresponding engaging portion of the second container. In one embodiment, the at least one depression 142 has a substantially constant depth and provides a protruding shelf 144 that extends along an inner surface of the first container 100. In this manner, the protruding shelf 144 provided by the at least one depression 142 engages an outer surface of the at least one depression 142 of the second container 100'. The at least one depression 142 in conjunction with the protruding shelf 144 assist in providing proper alignment of the nested first and second containers. Further, the at least one depression and protruding shelf also inhibit or limit independent rotation movement of each container, if needed. The at least one anti-rotation feature provides benefits during manufacturing, for example, during lip forming, such that the stack of nested container maintain proper alignment Further, the at least one depression is configured to maintain a spaced relationship between the sidewall of the first container and the sidewall of the second container. The spacing and lack of rotation movement prevents extensive wear on the containers.

Any of a variety of suitable polymers can be used for container of the present invention, including but not limited to polystyrenes and copolymers thereof, propylene polymers, such as, for example polypropylene homopolymers, polypropylene random copolymers, or polypropylene impact copolymers, ethylene polymers, such as, for example, high density polyethylene, medium density polyethylene, or low density polyethylene, polybutenes and copolymers thereof, polyesters, and mixtures or copolymers thereof. In accordance with a preferred embodiment, the container material can include at least one colorant. The colorant can be any suitable material capable of providing a vivid color, including, but not limited to any color of the spectrum, as well as white and black, to the material of the container. The colorants that can be used in the present invention include, but are not limited to, pigments or dyes. The colorants may be used in a variety of modes, including but not limited to, dry color, conventional color concentrates, liquid color and precolored resin. The colorant is provided in a sufficient concentration to provide the desired color.

It will be apparent to those skilled in the art that various modifications and variations can be made in the method and system of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention includes modifications and variations that are within the scope of the appended claims and their equivalents.

Claims

CLAIMS What is claimed is:

1. A container comprising: a base defining a closed bottom; and a side wall extending upwardly from the base, the side wall having an outer surface and at least one recess formed therein, the recessed surface having a surface texture different than a surface texture of the outer surface; and at least one anti-rotation interlock element disposed on the sidewall of the container and capable of engaging a similar anti-rotation interlock element of a second container.

2. The container of claim 1 wherein the at least one anti-rotation interlock element is disposed in a first or second portion of the sidewall of the container, or between said first and second portions.

3. The container of claim 1, wherein the at least one anti-rotation interlock element includes a protruding shelf having a depth varying along a height of the at least one anti-rotation interlock element.

4. The container of claim 3, wherein the depth increases along the height of the at least one anti-rotation interlock element.

5. The container of claim 3, wherein the depth decreases along the height of the at least one anti-rotation interlock element.

6. The container of claim 1 , wherein the base comprises a circumferentially oriented basewall and at least one anti-rotation interlock element disposed in the base wall of the container.

7. The container of claim 1, wherein the at least one anti-rotation interlock element is axially aligned with the at least one recess.

8. The container of claim 1 , wherein the container includes at least two recesses, and further wherein the at least one anti-rotation interlock element is disposed between the at least two recesses.

9. The container of claim 1 , further comprising a plurality of anti-rotation interlock elements.

10. The container of claim 9, wherein the plurality of anti-rotation interlock elements includes a first anti-rotation interlock element and a second anti-rotation interlock element, the first anti-rotation interlock element being disposed on an opposite side of the container than the second anti-rotation interlock element.

11. The container of claim 1 , wherein the at least one anti-rotation interlock element comprises a depression or a protuberance.

12. The container of claim 1, wherein the at least one anti-rotation element includes a finger grip configured to receive a finger.

13. The container of claim 12, wherein the finger grip has a surface, the surface being indented or raised.

14. The container of claim 12, wherein the surface of the finger grip includes texture.

15. The container of claim I₅ wherein the at least one anti-rotation interlock element has a curvilinear, polygonal, or polyhedronal surface.

16. A container comprising : a base defining a closed bottom; a sidewall extending upwardly from the base, the sidewall having an outer surface; and at least one anti-rotation interlock element formed in the sidewall, the anti- rotation interlock element including at least one recess having a recessed surface and a depth, the recessed surface having a surface texture different than a surface texture of the outer surface.

17. The container of claim 16, wherein the at least one recess has a curvilinear shape.

18. The container of claim 17, wherein the curvilinear shape is a parabola.

19. The container of claim 16, wherein the sidewall has a first portion proximate the base, and a second portion defining an open mouth, the at least one recess defining a boundary edge that extends at least partially into the second portion.

20. The container of claim 16, wherein the at least one anti-rotation interlock element includes a protruding shelf having a depth varying along a height of the at least one anti-rotation interlock element.

21. The container of claim 16, wherein the depth increases along the height of the at least one anti-rotation interlock element.

22. A stack of nestable containers, the stack comprising a first container; and a second container received within the first container; each of the first container and the second container being substantially similar in shape and including a base defining a closed bottom; and a side wall extending upwardly from the base, the side wall having an outer surface and at least one recess formed therein, the recessed surface having a surface texture different than a surface texture of the outer surface; and at least one anti-rotation interlock element disposed on the sidewall of the container.

23. The stack of claim 22, wherein the at least one anti-rotation interlock element includes at least one depression or at least one protuberance formed in the container.

24. The stack of claim 22, wherein the at least one anti-rotation interlock element includes a protruding shelf having a depth varying along a height of the at least one anti-rotation interlock element.

25. The stack of claim 24, wherein the depth increases along the height of the at least one anti-rotation interlock element.

26. The stack of claim 24, wherein the depth decreases along the height of the at least one anti-rotation interlock element.

27. The stack of claim 22, wherein the at least one anti-rotation element includes a finger grip.

28. The stack of claim 27, wherein the finger grip has an indented or raised surface.

29. The stack of claim 27, wherein the surface of the finger grip includes texture.

30. The stack of claim 22, wherein the at least one anti-rotation interlock element is configured as a curvilinear, polygonal, polyhedronal, square, triangular, diamond, pyramidal, chevron, or spherical shape.