US20160332783A1

US20160332783A1 - Lightweight Closure with Tamper Band

Info

Publication number: US20160332783A1
Application number: US14/709,198
Authority: US
Inventors: Sungsuk Steve Kim
Original assignee: Silgan White Cap LLC
Current assignee: Silgan White Cap LLC
Priority date: 2015-05-11
Filing date: 2015-05-11
Publication date: 2016-11-17
Also published as: CA2922179C; USD934074S1; USD993769S1; CA2922179A1; USD871905S1; USD1042132S1

Abstract

A light weight, reinforced, molded, plastic closure is provided. The closure includes an end wall and a sidewall. A portion of the end has been substantially thinned such that the portion of the end wall is substantially thinner than other portions of the closure such as the sidewall or outer peripheral end wall area. The closure may also include interrupted threads that also contributes to the low weight of the closure.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a closure for closing a container such as a dairy container. In particular, the present invention relates to a closure having one or more feature providing a strong or reinforced closure while also allowing the total weight of the closure to be decreased relative to conventional closures.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a light weight, reinforced, molded, plastic closure. The closure includes an end wall including an outer peripheral edge, an upper surface, a lower surface and a first thickness measured between the upper and lower surfaces. The closure includes a sidewall extending downward and away from the outer peripheral edge of the end wall, and the sidewall includes an inner surface, an outer surface and a second thickness measured between the inner and outer surfaces. The closure includes a container engagement structure extending radially inward from the inner surface of the sidewall. The closure includes a tamper-indicating band extending from a lower end of the sidewall, and the tamper-indicating band has a frangible section configured to break upon opening to provide a visual indication that the closure had been opened. The closure includes a plurality of raised ribs extending radially outward from the outer surface of the sidewall and extending along the sidewall at least a portion of the distance between the outer peripheral edge and the tamper-indicating band. The first thickness is less than 75% of the second thickness.
Another embodiment of the invention relates to a plastic closure. The closure includes an end wall having an outer peripheral edge, an upper surface, a lower surface and a first thickness measured between the upper and lower surfaces. The closure includes a sidewall extending downward and away from the outer peripheral edge of the end wall, and the sidewall includes an inner surface and an outer surface. The closure includes a container engagement structure extending radially inward from the inner surface of the sidewall. The closure includes a tamper-indicating band extending from a lower end of the sidewall, and the tamper-indicating band has a frangible section configured to break upon opening to provide a visual indication that the closure had been opened. The closure includes a plug extending downward from the lower surface of the end wall, and the plug is a continuous wall located within the outer peripheral edge of the end wall. The end wall includes an inner portion located within the plug and an outer portion located between the plug and the outer peripheral edge of the end wall. The first thickness is a thickness of the inner portion of the end wall, and the outer portion of the end wall has a second thickness. The first thickness is less than 75% of the second thickness.
Another embodiment of the invention relates to a molded, plastic closure. The closure includes an end wall including an outer peripheral edge, an upper surface, a lower surface and a first thickness measured between the upper and lower surfaces. The closure includes a sidewall extending downward and away from the outer peripheral edge of the end wall. The sidewall includes an inner surface, an outer surface and a second thickness measured between the inner and outer surfaces. The closure includes threading comprising a series of threads configured to engage cooperating threads of a container, and each thread of the threading includes at least four interrupts in which a section of the inner surface of the sidewall is located along the path of the thread. The closure includes a tamper-indicating band extending from a lower end of the sidewall, and the tamper-indicating band has a frangible section configured to break upon opening to provide a visual indication that the closure had been opened. The closure includes a sealing ring extending downward from the lower surface of the end wall, and the sealing ring is a circumferentially continuous annular wall and is substantially concentric with the outer peripheral edge of the end wall. The end wall includes an inner portion located within the sealing ring and an outer portion located between the sealing ring and the outer peripheral edge of the end wall. The first thickness is a thickness of the inner portion of the end wall, and the outer portion of the end wall has a third thickness. The first thickness is less than 75% of the second thickness and less than 75% of the third thickness, and at least 60% of the area of the lower surface of the end wall is located within the sealing ring.
Various embodiments of the invention relate to any of the features, structures, elements, parameters, method steps, systems, components, subsystems, etc. described and shown herein, and various embodiments of the invention relate to any combination the features, structures, elements, parameters, method steps, systems, components, subsystems, etc. described and shown herein.
Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This application will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements in which:

FIG. 1 is a perspective view from above of a closure according to an exemplary embodiment;

FIG. 2 is perspective view from below of the closure of FIG. 1 according to an exemplary embodiment;

FIG. 3 is a bottom plan view of the closure of FIG. 1 according to an exemplary embodiment;

FIG. 4 is a side cross-sectional view of the closure of FIG. 1 taken along line 4-4 shown in FIG. 3 according to an exemplary embodiment;

FIG. 5 is a detailed side cross-sectional view of the closure of FIG. 1 taken along line 5-5 shown in FIG. 4 according to an exemplary embodiment;

FIG. 6 is a perspective view from above of a closure according to another exemplary embodiment;

FIG. 7 is perspective view from below of the closure of FIG. 6 according to an exemplary embodiment;

FIG. 8 is a bottom plan view of the closure of FIG. 6 according to an exemplary embodiment;

FIG. 9 is a side cross-sectional view of the closure of FIG. 6 taken along line 9-9 shown in FIG. 8 according to an exemplary embodiment;

FIG. 10 is a detailed side cross-sectional view of the closure of FIG. 6 taken along line 10-10 shown in FIG. 8 according to an exemplary embodiment;

DETAILED DESCRIPTION

Referring generally to the figures, a lightweight closure having one or more reinforcement element is shown. In general, the closures discussed herein have a thin end wall and interrupted threading that allows the closure to be made using less material than typical conventional closures. However, reducing the amount of material (e.g., plastic) contained within the closure tends to result in a closure that is more prone to breakage or failure. Accordingly, the closure discussed herein includes various reinforcing elements that Applicant's have found provide both a lightweight closure and one that is sufficiently strong. For example, the closure discussed herein includes one or more localized thickened section in the end wall of the closure that provides strength at key areas of the closure (e.g., areas that tend to experience higher forces during filling, capping or handling) while allowing less material to be used in other areas. In addition, the features of the closure discussed herein provides higher capping efficiency (at least in some capping environments). For example it has been found that the closure discussed herein is flexible such that the closure is able to be bent slightly to snap the threading into place in situations where the capping machine has misaligned the closure with the container threading. This bending and increased capping efficiency is not provided by more rigid conventional closures.
Referring to FIG. 1, a closure 10 is shown according to an exemplary embodiment. Closure 10 includes an end wall or top portion, shown as an top panel 12. As shown, top panel 12 is generally circular in shape and is generally planar (i.e., the outer surface of top panel 12 is flat, positioned substantially in a single plane, shown as a generally horizontal plane in FIG. 1A). Closure 10 includes a sidewall, shown as skirt 14, and a transition section, shown as a corner section 16. Corner section 16 extends outwardly and downwardly from the outer, peripheral edge of top panel 12, and skirt 14 extends downwardly from the outer, peripheral edge of corner section 16. As shown in FIG. 1, skirt 14 is generally annular in cross-section and is substantially perpendicular to the plane defined by top panel 12. Closure 10 also includes a plurality of raised ribs 18 extending radially outward from an outer surface of skirt 14. As shown ribs 18 extend vertically along at least a portion of the vertical length of the outer surface of skirt 14. Ribs 18 provide a texture or gripping surface that may facilitate opening of the closure.
As shown in FIG. 2, closure 10 includes a container engagement structure, shown as threading 20. Threading 20 extends inwardly from the inner surface of skirt 14. Threading 20 is configured to engage corresponding threading present on the container to which closure 10 is attached. In various other embodiments, closure 10 may include other engagement structures, such as snap beads, lugs, etc.
In the embodiment shown, threading 20 comprises a series of raised, radially inwardly extending threads, shown as threads 22 and 24. As will be understood threads 22 and 24 generally follow a helical path along the inner surface of closure 10 which allows the threads to engage the cooperating structures on the container. As shown in FIG. 2, each of the threads of threading 20 includes at least one, and more specifically, at least four, interrupts 26. Interrupts 26 are breaks in the thread such that a portion of the inner surface of skirt 14 having the same thickness as other regions of skirt 14 without threads are located along the path of adjacent thread sections. In other words, because threading 20 is formed by localized increase in thickness of the material of the closure to form the thread structure, interrupts 26 are simply regions where the increased thickness that forms that thread has not been formed.
Referring to FIGS. 1 and 2, skirt 14 may include a tamper evidencing structure. In this embodiment, skirt 14 includes a tamper band 28 coupled to a lower end of skirt 14 by series of frangible connections 30. Upon application of twisting force to closure 10 to remove closure 10 from a container neck, frangible connections 30 are configured to break, separating tamper band 28 from skirt 14. This separation provides a visual indication to the user or purchaser of the container including closure 10 of whether closure 10 has previously been removed from the container.
As shown in FIG. 3, tamper band 28 includes a plurality of pleats 32 and plurality of curved band sections 34 located between pleats 32. In general, pleats 32 engage cooperating structures on the neck of the container to prevent closure 10 from being removed from the container without frangible connections 30 breaking. Further, pleats 32 also facilitate application of closure 10 on to the container by allowing tamper band 28 to expand without breaking frangible connections 30. In the exemplary embodiment shown, closure 10 includes eight pleats 32 and eight curved band sections 34 located between each pleat 32 around the circumference of tamper band 28. In other embodiments, closure 10 may include 6, 10, 12, 14, etc. pleats 32 depending on the size and application for a particular closure 10.
As shown in FIG. 3, closure 10 includes plurality of radially extending ribs, shown as reinforcement ribs 40. As will be explained in more detail below, reinforcement ribs 40 are thickened sections of top panel 12 that act to reinforce thin end wall sections 42. As shown in FIGS. 2 and 3, reinforcement ribs 40 extend radially outward in a star-like shape to thickened end wall section 44 adjacent to sealing ring 46. In this embodiment, reinforcement ribs 40 extend outward from a raised hub section 48 which is located at the center point of top panel 12. As shown in FIG. 3, both inner thickened end wall section 44 and sealing ring 46 are concentric with the outer peripheral edge of top panel 12 and with each other, and in the embodiment shown are concentric around hub 48.
In various embodiments, sealing ring 46 is positioned such that a substantial portion of the area of top panel 12 is located within the inner radially facing surface of sealing ring 46. In one embodiment, at least 60%, and more specifically, at least 70% of the area of top panel 12 is located within the inner radially facing surface of sealing ring 46. In various embodiments, these relative percentages may relate to the area of the upper surface and/or the lower surface of top panel 12.
Referring to FIG. 4, a cross-sectional view taken through one of the reinforcement ribs 40 is shown according to an exemplary embodiment. As can be seen in FIG. 4, the thickness of reinforcement ribs 40, shown as T5, is the distance between upper surface 50 and lower surface 52 of closure 10, and in the embodiment shown, the thickness of reinforcement rib 40 is substantially the same as the thickness through inner thickened end wall section 44. Further, sealing ring 46 extends downward from lower surface 52 of top panel 12 forming a substantially annular ring within closure 10. In various embodiments, sealing ring 46 is an annular, uninterrupted, continuous ring or wall extending 360 degrees from lower surface 52. As will be understood, sealing ring 46 acts to engage a portion of the neck of the container to which closure 10 is attached to form a seal. In general, thickened end wall section 44 provides a reinforced area between thin end wall section 42 and sealing ring 46 that limits or prevents distortion of the end wall as sealing ring 46 engages with a container neck during sealing.
Referring to FIG. 5, details of the thinned sections and the reinforcement sections of closure 10 are shown. Thin end wall section 42 of top panel 12 has a thickness shown as T1. Skirt 14 has a thickness shown as T2 which is the base sidewall thickness at a position between raised ribs 18 and at a position not occupied by threading 20. Thickened end wall section 44 has a thickness shown as T3.
In various embodiments, T1 is less than 75% of T2 and T3, and more specifically is less than 70% of T2 and T3. In various embodiments, T1 is between 0.01 inches and 0.03 inches, specifically is between 0.015 inches and 0.028 inches and more specifically is 0.020 inches plus or minus 0.003 inches. In various embodiments, T2 is between 0.025 inches and 0.045 inches, specifically is between 0.030 inches and 0.040 inches and more specifically is 0.032 inches plus or minus 0.003 inches. In various embodiments, T3 is between 0.02 inches and 0.04 inches, specifically is between 0.025 inches and 0.035 inches and more specifically is 0.030 inches plus or minus 0.003 inches.
As shown in FIG. 5, top panel 12 includes an outer portion 54. Outer portion 54 is located outside of sealing ring 46 and is concentric with sealing ring 46, the outer peripheral edge of top panel 12, and with inner thickened end wall section 44. Outer portion 54 has a thickness shown as T4. In various embodiments, T1 is less than 75% of T4, and more specifically is less than 70% of T4. Similar to thickened end wall section 44, thickened outer portion 54 also acts to support sealing ring 46. In various embodiments, T4 is between 0.025 inches and 0.045 inches, specifically is between 0.030 inches and 0.040 inches and more specifically is 0.035 inches plus or minus 0.003 inches.
As shown in FIG. 5, lower surface 52 of top panel 12 includes an angled transition section 56. Angled transition section 56 provides a gradual transition between the lower thickness of thinned end wall sections 42 and thickened end wall section 44. In the embodiment shown, angled transition section 56 defines an angle A relative to an axis perpendicular to top panel 12. In various embodiments, angle A is between 0 and 20 degrees, specifically between 1 and 9 degrees, and more specifically is 5 degrees plus or minus 1 degree.
Referring back to FIG. 4, reinforcement ribs 40 have a thickness T5. In one embodiment, T5 is the same as T3 discussed above. In various embodiments, T1 is less than 75% of T5 and more specifically is less than 70% of T5. In various embodiments, T5 is between 0.02 inches and 0.04 inches, specifically is between 0.025 inches and 0.035 inches and more specifically is 0.030 inches plus or minus 0.003 inches.
In order to provide substantial light weighting and materials savings, a substantial portion of top panel 12 is formed at thickness T1. In various embodiments, at least 50% of top panel 12 has a thickness at T1 as discussed herein, and in a specific embodiment, at least 75% of top panel 12 has a thickness at T1 as discussed herein. In various embodiments, the percent of top panel 12 having thickness T1 is determined by the percentage of the surface area of lower surface 52 at which top panel 12 has thicknesses of T1 as discussed herein relative to the total surface area of lower surface 52. In various embodiments, the absolute and relative thicknesses discussed herein may relate to the average thicknesses within particular regions of the closure, and in other embodiments, the absolute and relative thicknesses discussed herein may relate to a thickness measured at one or more positions within a particular regions of closure 10.
In various exemplary embodiments, Applicants have found that the various relative thicknesses, absolute thicknesses and dimensions discussed herein provide various functional improvements including a satisfactorily strong closure while also reducing the overall weight of the closure. In addition, the closure design discussed herein provides a cap that maintains a seal on a container while also having a reduced weight. Further, the closure design discussed herein provides a cap that decreases the rate of capping errors by the capping machinery due to the flexibility of the lightweight closure (particularly in skirt 14 provided by interrupted threading 20). This flexibility allows snap on of closure 10 in the event of misalignment of the threads of the closure and of the cap. These functional improvements are believed to result directly from the various relative thicknesses and absolute thicknesses discussed herein while at the same time providing a strong, robust, break-resistant closure able to seal tightly onto the container neck.
Referring to FIGS. 6-10, another embodiment of reinforced, light weight closure, shown as closure 100, is shown. Closure 100 is substantially the same as closure 10 except as discussed herein. Closure 100 includes an top panel 102 that is relative thin and light-weighted relative to other portions of closure 100. As can be seen in FIGS. 7 and 8, top panel 102 does not include reinforcement ribs. Rather, as shown in FIG. 9, top panel 102 has a circular shaped thin central section 104 that has a substantially consistent thickness within thickened end wall section 44. In various embodiments, thin central section 104 may have a thickness that is not as thin as sections of 42 of closure 10, but rather reinforces thin central section 104 by having a slightly higher but even thickness.
Referring to FIG. 10, thinned central section 104 has a thickness shown as T6. In various embodiments, T6 is less than 75% of T2, T3 and T4, and more specifically is less than 70% of T2, T3 and T4. In various embodiments, T6 is between 0.01 inches and 0.03 inches, specifically is between 0.015 inches and 0.028 inches and more specifically is 0.022 inches plus or minus 0.003 inches.
In order to provide substantial light weighting and materials savings a substantial portion of top panel 102 is formed at thickness T6. In various embodiments, at least 50% of top panel 102 has a thickness at T6 as discussed herein, and in a specific embodiment, at least 75% of top panel 12 has a thickness at T6 as discussed herein. In various embodiments, the percent of top panel 102 having thickness T6 is determined by the percentage of the surface area of lower surface 52 at which top panel 102 thicknesses T6 as discussed herein relative to the total surface area of lower surface 52. In various embodiments, the absolute and relative thicknesses discussed herein may relate to the average thicknesses within particular regions of closure 100, and in other embodiments, the absolute and relative thicknesses discussed herein may relate to a thickness measured at one or more positions within a particular regions of closure 100.
In various embodiments, the closures discussed herein may be used to seal a wide variety of containers. In various embodiments, the closures discussed herein are closures suitable for maintaining a hermetic seal. In various embodiments, closure 10 is a closure configured to seal a container configured to hold consumable or edible products (e.g., beverages, water, food, etc.). In various embodiments, closure 10 is configured to seal a container that is a molded (e.g., blow-molded) thermoplastic beverage container configured to hermetically hold a beverage (e.g., water, juice, fortified or nutrient water, tea, sports drink, energy drink, milk, milk-based beverages, etc.). In other embodiments, closure 10 can be used to seal a wide variety of containers including pouches, jars, metal bottles, paper board cartons, etc. In a specific embodiment, closure 10 is configured to seal a dairy container, such as a milk jug or milk carton.
In various embodiments, the closure and spout discussed herein are made from plastic. In various embodiments, the closure and spout are made from compression molded plastic, and in other embodiments, the closure and spout are made from injection molded plastic. In various embodiments, the plastics include PE, PP, PET, PVC, etc.
It should be understood that the figures illustrate the exemplary embodiments in detail, and it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.
Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements, shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.
For purposes of this disclosure, the term “coupled” means the joining of two components directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional member being attached to one another. Such joining may be permanent in nature or alternatively may be removable or releasable in nature.
In various exemplary embodiments, the relative dimensions, including angles, lengths and radii, as shown in the Figures are to scale. Actual measurements of the Figures will disclose relative dimensions, angles and proportions of the various exemplary embodiments. Various exemplary embodiments extend to various ranges around the absolute and relative dimensions, angles and proportions that may be determined from the Figures. Various exemplary embodiments include any combination of one or more relative dimensions or angles that may be determined from the Figures. Further, actual dimensions not expressly set out in this description can be determined by using the ratios of dimensions measured in the Figures in combination with the express dimensions set out in this description. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.

Claims

1. A light weight, reinforced, molded, plastic closure comprising:

an end wall including an outer peripheral edge, an upper surface, a lower surface and a first thickness measured between the upper and lower surfaces;

a sidewall extending downward and away from the outer peripheral edge of the end wall, the sidewall including an inner surface, an outer surface and a second thickness measured between the inner and outer surfaces;

a container engagement structure extending radially inward from the inner surface of the sidewall;

a tamper-indicating band extending from a lower end of the sidewall, the tamper-indicating band having a frangible section configured to break upon opening to provide a visual indication that the closure had been opened; and

a plurality of raised ribs extending radially outward from the outer surface of the sidewall and extending along the sidewall at least a portion of the distance between the outer peripheral edge and the tamper-indicating band;

a circumferentially continuous annular wall extending downward from the lower surface of the end wall;

the end wall including an inner section having an outer peripheral edge adjacent an inner surface of the annular wall and a center portion, the outer peripheral edge of the inner section and the center portion each having a third thickness;

at least a portion of the inner section located between the center portion and the outer peripheral edge of the inner section having a thickness equal to the first thickness;

wherein the first thickness is less than the third thickness; and

wherein the first thickness is less than 75% of the second thickness.

2. The closure of claim 1, wherein the end wall includes an outer portion located between the annular wall and the outer peripheral edge of the end wall, wherein the outer portion of the end wall has a fourth thickness, wherein the first thickness is less than 75% of the fourth thickness.

3. The closure of claim 2 wherein the container engagement structure includes a threading comprising a series of threads configured to engage cooperating threads of a container, wherein each thread of the threading includes at least one interrupt in which a section of the inner surface of the sidewall is located along the path of the thread.

4. The closure of claim 3 wherein at least 60% of the area of the lower surface of the end wall is located within the annular wall, wherein each thread of the threading includes at least three interrupts.

5. The closure of claim 2, wherein the first thickness is less than 75% of the third thickness.

6. The closure of claim 5 wherein the first thickness is between 0.01 inches and 0.03 inches, wherein the second thickness is between 0.025 inches and 0.035 inches, wherein the fourth thickness is between 0.03 inches and 0.04 inches, and wherein the third thickness is between 0.02 inches and 0.04 inches.

7. The closure of claim 5 further comprising a series of radial ribs located along the end wall and extending radially outward from a center point of the end wall, wherein the radial ribs have a fifth thickness, wherein the first thickness is less than 75% of the fifth thickness.

8. The closure of claim 1 wherein at least 50% of the end wall has a thickness that is less than 75% of the second thickness.

9. The closure of claim 1 wherein the second thickness is measured between opposing vertical portions of the inner surface and outer surface of the sidewall at a position above the container engagement structure.

10. A plastic closure, comprising:

a sidewall extending downward and away from the outer peripheral edge of the end wall, the sidewall including an inner surface and an outer surface;

a plug extending downward from the lower surface of the end wall, wherein the plug is a continuous wall located within the outer peripheral edge of the end wall;

wherein the end wall includes an inner portion located within the plug and an outer portion located between the plug and the outer peripheral edge of the end wall, the outer portion having a first peripheral edge located adjacent an outer surface of the plug and a second peripheral edge located adjacent the outer peripheral edge of the end wall;

wherein the first thickness is a thickness of the inner portion of the end wall;

wherein at least a portion of the outer portion of the end wall has a second thickness;

wherein the first thickness is less than 75% of the second thickness; and

wherein the thickness of the first peripheral edge is substantially the same as the thickness of the second peripheral edge.

11. The closure of claim 10 wherein the sidewall includes a third thickness measured between the inner and outer surfaces, wherein the first thickness is less than 75% of the third thickness.

12. The closure of claim 11 wherein the container engagement structure includes a threading comprising a series of threads configured to engage cooperating threads of a container, wherein each thread of the threading includes at least one interrupt in which a section of the inner surface of the sidewall is located along the path of the thread.

13. The closure of claim 12 wherein at least 60% of the area of the lower surface of the end wall is located within the plug, wherein each thread of the threading includes at least three interrupts.

14. The closure of claim 13 wherein the inner portion of the end wall includes a thickened region that transitions into an inner surface of the sealing ring, the thickened region concentric with the plug and with the outer peripheral edge of the end wall, wherein the thickened region has a fourth thickness, wherein the first thickness is less than 75% of the fourth thickness.

15. The closure of claim 14 further comprising a series of ribs extending radially outward from a center point of the end wall, wherein the ribs have a fifth thickness, wherein the first thickness is less than 75% of the fifth thickness.

16. The closure of claim 15 wherein at least 50% of the end wall has a thickness that is less than 75% of the second thickness.

17. The closure of claim 16 wherein the first thickness is between 0.01 inches and 0.03 inches, wherein the second thickness is between 0.025 inches and 0.035 inches, wherein the third thickness is between 0.03 inches and 0.04 inches, and wherein the fourth thickness is between 0.025 inches and 0.035 inches.

18. The closure of claim 10 wherein the second thickness is measured between opposing vertical portions of the inner surface and outer surface of the sidewall at a position above the container engagement structure.

19. A molded, plastic closure comprising:

threading comprising a series of threads configured to engage cooperating threads of a container, wherein each thread of the threading includes at least three interrupts in which a section of the inner surface of the sidewall is located along the path of the thread;

a sealing ring extending downward from the lower surface of the end wall, wherein the sealing ring is a circumferentially continuous annular wall and is substantially concentric with the outer peripheral edge of the end wall;

wherein the end wall includes an inner portion located within the sealing ring and an outer portion located between the sealing ring and the outer peripheral edge of the end wall, the inner portion having an outer periphery extending circumferentially about and adjacent to an inner surface of the sealing ring;

wherein the outer portion of the end wall has a third thickness;

wherein the first thickness is less than 75% of the second thickness and less than 75% of the third thickness;

wherein at least 60% of the area of the lower surface of the end wall is located within the sealing ring; and

wherein the thickness of the closure as measured about the outer periphery of the inner portion is substantially constant about the entirety of the circumference of the outer periphery.

20. The closure of claim 19 wherein the first thickness is between 0.01 inches and 0.03 inches, wherein the second thickness is between 0.025 inches and 0.035 inches, wherein the third thickness is between 0.03 inches and 0.04 inches.