CA1117478A - Closure cap - Google Patents
Closure capInfo
- Publication number
- CA1117478A CA1117478A CA000335781A CA335781A CA1117478A CA 1117478 A CA1117478 A CA 1117478A CA 000335781 A CA000335781 A CA 000335781A CA 335781 A CA335781 A CA 335781A CA 1117478 A CA1117478 A CA 1117478A
- Authority
- CA
- Canada
- Prior art keywords
- cap
- seal
- wall
- interior wall
- container
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Closures For Containers (AREA)
Abstract
Case EPC-4509 Canada CLOSURE CAP
Abstract of the Invention A package for containing a product, e. g., carbonated beverages, capable of producing internal pressure is disclosed.
The package features a cap having an annular top was and an annular sidewall downwardly depending from the top wall and having on its inside surface an inwardly projecting helical thread for cooperation with the threaded neck of the container.
An annular interior wall depends downwardly from the top wall and is displaced radially inward from the sidewall to provide an annular space into which the upper portion of the container neck can nest. On nesting, the container neck forms, with the inside surface of the top wall or the outside surface of the interior wall, at least one seal. A concave wall is also provided and is attached at its circumference to the lower end of the interior wall. The concave wall is flexible for upward flexing in response to the internal pressure whereby the interior wall is pressed outwardly to form a second seal against the inside surface of the container neck when the flexing occurs.
The latter seal increases in fidelity in response to the in-crease in internal container pressure.
Abstract of the Invention A package for containing a product, e. g., carbonated beverages, capable of producing internal pressure is disclosed.
The package features a cap having an annular top was and an annular sidewall downwardly depending from the top wall and having on its inside surface an inwardly projecting helical thread for cooperation with the threaded neck of the container.
An annular interior wall depends downwardly from the top wall and is displaced radially inward from the sidewall to provide an annular space into which the upper portion of the container neck can nest. On nesting, the container neck forms, with the inside surface of the top wall or the outside surface of the interior wall, at least one seal. A concave wall is also provided and is attached at its circumference to the lower end of the interior wall. The concave wall is flexible for upward flexing in response to the internal pressure whereby the interior wall is pressed outwardly to form a second seal against the inside surface of the container neck when the flexing occurs.
The latter seal increases in fidelity in response to the in-crease in internal container pressure.
Description
~li7478 Background of the Invention A trend has developed in the carbonated beverage indus-try to utilize plastic bottles for packaging of the beverage.
These bottles are advantageous in that they are light weight and for the most part unbreakable. Since metal crimp-on caps are not suitable for use with plastic bottles, the industry is presently searching for a container cap which will effectively seal the container and which can be repeatedly removed and replaced without loss of sealing function. Presently, the in-dustry is utilizing metal screw caps which have the ability to be removed and replaced on the container with acceptable sealing qualities. In trying to improve the sealing qualities of the cap and in trying to provide a cap which may be recyclable along with the container, attention has been drawn to the utilization of thermoplastic caps. If the plastic cap is of the same material as the bottle, recycle of the entire package is possible. The greatest difficulty realized when utilizing plastic caps is the inability of most present day caps to form an air-tight seal when internal package pressure rises due to temperature changes or agitation of the carbonated beverage. Most plastic caps are capable of forming air-tight seals until internal package pres-sure increases. With an increasein internal package pressure the plastic cap is deformed thereby destroying the air-tight seal.
It is therefore an object of this invention to provide a thermoplastic cap which is capable of forming an air-tight seal with the container even when internal package pressure is present.
It is further an object of this invention to provide a closure which develops a tighter seal in response to the increase in internal package pressure.
T~E INVE~ITION
This invention relates to a thermoplastic cap for fitment to a container having a threaded neck, the cap comprising:
a. an annular top wall;
These bottles are advantageous in that they are light weight and for the most part unbreakable. Since metal crimp-on caps are not suitable for use with plastic bottles, the industry is presently searching for a container cap which will effectively seal the container and which can be repeatedly removed and replaced without loss of sealing function. Presently, the in-dustry is utilizing metal screw caps which have the ability to be removed and replaced on the container with acceptable sealing qualities. In trying to improve the sealing qualities of the cap and in trying to provide a cap which may be recyclable along with the container, attention has been drawn to the utilization of thermoplastic caps. If the plastic cap is of the same material as the bottle, recycle of the entire package is possible. The greatest difficulty realized when utilizing plastic caps is the inability of most present day caps to form an air-tight seal when internal package pressure rises due to temperature changes or agitation of the carbonated beverage. Most plastic caps are capable of forming air-tight seals until internal package pres-sure increases. With an increasein internal package pressure the plastic cap is deformed thereby destroying the air-tight seal.
It is therefore an object of this invention to provide a thermoplastic cap which is capable of forming an air-tight seal with the container even when internal package pressure is present.
It is further an object of this invention to provide a closure which develops a tighter seal in response to the increase in internal package pressure.
T~E INVE~ITION
This invention relates to a thermoplastic cap for fitment to a container having a threaded neck, the cap comprising:
a. an annular top wall;
- 2 -1i7478 ~
b. an annular sidewall downwardly depending from the top wall and having on its inside surface an inwardly projecting helical thread for cooperation with the container neck;
c. an annular interior wall downwardly depending from the top wall, the interior wall displaced radially inward from the sidewall to provide an annular space into which the upper portion of the container neck can nest to form, with the inside surface of the top wall or the outside surface of the interior wall, at least one seal; and, d. a concave wall attached at its circumference to the lower end of the interior wall, the concave wall being flexible for upward flexing in response to internal container pressure whereby the interior wall is pressed outwardly to form a second seal against the inside surface of the container neck when fle~ing occurs.
Since the concave wall flexes outwardly in response to the internal package pressure, the annular interior wall, which is connected to the concave wall at the concave wall circumference, is forced out-wardly against the inside surface of the container neck to achieve a seal. The first seal, formed by the container neck nesting with-in the annular space, is necessary so that pressure can build to cause the necessary flex in the concave wall. In a preferred form, an additional seal is provided in the annular space. In this instance, the container neck presses against the inside surface of the top wall and against the outside surface of the interior wall to form these two seals.-fl ~ 7478 The closures of this invention are preferably made ofpolyethylene terephthalate or of a polyolefin such as polypropylene.
Olher thermoplastic materials may be utilized as long as they are of sufficient strength to prevent an inversion of the concave wall but are at the same time flexible enough to form the before-mentioned seals.
These and other features of this invention, contributing to economy of manufacture and ease in use, will be more fully understood from the following description and figures in which:
FIGURE 1 is a partial, broken away, elevational view of a package of this invention prior to internal package pressure being exerted against the con-cave wall;
FIGURE 2 is a partial, broken away, elevational view of the package shown in Figure 1 when the internal - package pressure is exerted against the concave wall;
FIGURE 3 is a vertical sectional view taken through the closure shown in Figure l;
FIGURE 4 is an enlarged detailed view showing the seals formed in Figure l; and, FIGURE 5 is an enlarged detailed view showing the seals formed in Figure 2.
Referring now to Figures 1 thru 5, it can be seen that a package of this invention, generally designated by the numeral 10, comprises a container, generally designated by the numeral 14, and a cap, generally designated by the numeral 12. Container 19 has a neck 30 having on its outside surface an outwardly extending heli-cal thread 32. Container 14 can either be of a thermoplastic ~1~7478 material or glass. Generally, lt has been found preferable for container 14 to be oE a thermoplastic material in view of the eco-nomy of manufacture and the reduction in weight of the package.
When container 14 is of thermoplastic material, it has been found quite beneficial to utilize polyethylene terephthalate as a mate-rial of construction.
Cap 12 is seen to have a top wall 18 and an integral downwardly depending annular sidewall 15. Top wall 18, in the pre-ferred embodiment shown in the drawings, has a frustoconical inside surface. This inside surface will be utilized, as hereinafter des-cribed, to form one of two seals with the upper portion of con-tainer neck 30. It should be understood, however, that top wall 18 may have other configurations to form a seal with the upper portion of container neck 30 without detracting from the efficacy of the package. For example, top wall 18 could have a horizontal inside wall which would bear downwardly onto the top of the upper most portion of container neck 30 to form a seal. However, the utiliza-tion of a frustoconical inside wall does provide a very efficacious seal with container neck 30 since the frustoconical wall will bear down onto the outside corner of the top of container neck 30.
Downwardly depending from top wall 18 is an annular inte-rior wall 20. Annular interior wall 20 is displaced radially inward to provide an annular space 21 which is shown in Figure 3.
Within annular space 21 will nest the upper portion of container neck 30 as is shown in Figures 1, 2, 4, and 5. A seal can be formed between the outside surface of the interior wall and the upper portion of container neck 30 as is shown in the same figures.
In the embodiment shown in the drawings, two seals, seal 26 and seal 24, are formed by the nesting of container neck 30 pc/ ~7 11~7478 within annular space 21. The primary purpose of these seals is to provide enough of a seal by cap 12 so that the lnternal package pressure can build sufficiently to act against concave wall 22 to affect the final seal as hereinafter described. In some instances, it will be possible to affect this primary sealing by utilization of on:ly one seal, for example, seal 24 alone or seal 26 alone, may be sufficient.
At the lower most end of annular interior wall 20, there is integrally formed thereto concave wall 22. Concave wall 22 is attached to the interior wall at the circumference of concave wall 22. Concave wall 22 should be of a thickness so that it will flex upward under the influence of expected internal package pressure.
For most thermoplastics, suitable for use as the material of con-struction for the cap of this invention, it has been found that a concave wall thickness within the range of from about 0.025 to about 0.050 inches will give the flex desired. Adjacent to point of intersection between concave wall 22 and annular interior wall 20 is preferably an annular bead 20a. Annular bead 20a is utilized to provide a high fidelity seal when concave wall 22 is flexed slightly upward by internal package pressure as is shown in Figure 2. Deletion of annular bead 20a is permissible and in these instances the seal formed will occur primarily along the lower por-tion of the outside surface of annular interior wall 20.
Figures 1~ 2, 4, and 5 show the action of concave wall 22 upon annular interior wall 20. When cap 12 is first applied to container 14 to form package 10, seals 24 and 26 are formed by nesting of the upper portion of container neck 30 into annular space 21 which causes top wall 18 and annular interior wall 20 to be pressed against the upper end of container neck 30. Now that a pc/~, primary seal has been formed, pressure can build wlthin package 10.
When t:his increase in preHsure occurs, the pressure will act upon concave wall 22 causing lt to flex slightly upward and thereby lncrease its circumference. When this occurs, annular interior wall 20 is forced outwardly so that sealing bead 20a presses against the inside surface of container neck 30 to form final seal 28 which is shown in Figures 2 and 5. The higher the pressure rises, the greater the force to form seal 28 thereby insuring that there is no gaseous escape from package 10.
Both the container and cap of this invention may be made by conventional meansD The cap lends itself very readily to pro-duction by injection molding while the container can be made by any one of the many known blowing techniques.
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b. an annular sidewall downwardly depending from the top wall and having on its inside surface an inwardly projecting helical thread for cooperation with the container neck;
c. an annular interior wall downwardly depending from the top wall, the interior wall displaced radially inward from the sidewall to provide an annular space into which the upper portion of the container neck can nest to form, with the inside surface of the top wall or the outside surface of the interior wall, at least one seal; and, d. a concave wall attached at its circumference to the lower end of the interior wall, the concave wall being flexible for upward flexing in response to internal container pressure whereby the interior wall is pressed outwardly to form a second seal against the inside surface of the container neck when fle~ing occurs.
Since the concave wall flexes outwardly in response to the internal package pressure, the annular interior wall, which is connected to the concave wall at the concave wall circumference, is forced out-wardly against the inside surface of the container neck to achieve a seal. The first seal, formed by the container neck nesting with-in the annular space, is necessary so that pressure can build to cause the necessary flex in the concave wall. In a preferred form, an additional seal is provided in the annular space. In this instance, the container neck presses against the inside surface of the top wall and against the outside surface of the interior wall to form these two seals.-fl ~ 7478 The closures of this invention are preferably made ofpolyethylene terephthalate or of a polyolefin such as polypropylene.
Olher thermoplastic materials may be utilized as long as they are of sufficient strength to prevent an inversion of the concave wall but are at the same time flexible enough to form the before-mentioned seals.
These and other features of this invention, contributing to economy of manufacture and ease in use, will be more fully understood from the following description and figures in which:
FIGURE 1 is a partial, broken away, elevational view of a package of this invention prior to internal package pressure being exerted against the con-cave wall;
FIGURE 2 is a partial, broken away, elevational view of the package shown in Figure 1 when the internal - package pressure is exerted against the concave wall;
FIGURE 3 is a vertical sectional view taken through the closure shown in Figure l;
FIGURE 4 is an enlarged detailed view showing the seals formed in Figure l; and, FIGURE 5 is an enlarged detailed view showing the seals formed in Figure 2.
Referring now to Figures 1 thru 5, it can be seen that a package of this invention, generally designated by the numeral 10, comprises a container, generally designated by the numeral 14, and a cap, generally designated by the numeral 12. Container 19 has a neck 30 having on its outside surface an outwardly extending heli-cal thread 32. Container 14 can either be of a thermoplastic ~1~7478 material or glass. Generally, lt has been found preferable for container 14 to be oE a thermoplastic material in view of the eco-nomy of manufacture and the reduction in weight of the package.
When container 14 is of thermoplastic material, it has been found quite beneficial to utilize polyethylene terephthalate as a mate-rial of construction.
Cap 12 is seen to have a top wall 18 and an integral downwardly depending annular sidewall 15. Top wall 18, in the pre-ferred embodiment shown in the drawings, has a frustoconical inside surface. This inside surface will be utilized, as hereinafter des-cribed, to form one of two seals with the upper portion of con-tainer neck 30. It should be understood, however, that top wall 18 may have other configurations to form a seal with the upper portion of container neck 30 without detracting from the efficacy of the package. For example, top wall 18 could have a horizontal inside wall which would bear downwardly onto the top of the upper most portion of container neck 30 to form a seal. However, the utiliza-tion of a frustoconical inside wall does provide a very efficacious seal with container neck 30 since the frustoconical wall will bear down onto the outside corner of the top of container neck 30.
Downwardly depending from top wall 18 is an annular inte-rior wall 20. Annular interior wall 20 is displaced radially inward to provide an annular space 21 which is shown in Figure 3.
Within annular space 21 will nest the upper portion of container neck 30 as is shown in Figures 1, 2, 4, and 5. A seal can be formed between the outside surface of the interior wall and the upper portion of container neck 30 as is shown in the same figures.
In the embodiment shown in the drawings, two seals, seal 26 and seal 24, are formed by the nesting of container neck 30 pc/ ~7 11~7478 within annular space 21. The primary purpose of these seals is to provide enough of a seal by cap 12 so that the lnternal package pressure can build sufficiently to act against concave wall 22 to affect the final seal as hereinafter described. In some instances, it will be possible to affect this primary sealing by utilization of on:ly one seal, for example, seal 24 alone or seal 26 alone, may be sufficient.
At the lower most end of annular interior wall 20, there is integrally formed thereto concave wall 22. Concave wall 22 is attached to the interior wall at the circumference of concave wall 22. Concave wall 22 should be of a thickness so that it will flex upward under the influence of expected internal package pressure.
For most thermoplastics, suitable for use as the material of con-struction for the cap of this invention, it has been found that a concave wall thickness within the range of from about 0.025 to about 0.050 inches will give the flex desired. Adjacent to point of intersection between concave wall 22 and annular interior wall 20 is preferably an annular bead 20a. Annular bead 20a is utilized to provide a high fidelity seal when concave wall 22 is flexed slightly upward by internal package pressure as is shown in Figure 2. Deletion of annular bead 20a is permissible and in these instances the seal formed will occur primarily along the lower por-tion of the outside surface of annular interior wall 20.
Figures 1~ 2, 4, and 5 show the action of concave wall 22 upon annular interior wall 20. When cap 12 is first applied to container 14 to form package 10, seals 24 and 26 are formed by nesting of the upper portion of container neck 30 into annular space 21 which causes top wall 18 and annular interior wall 20 to be pressed against the upper end of container neck 30. Now that a pc/~, primary seal has been formed, pressure can build wlthin package 10.
When t:his increase in preHsure occurs, the pressure will act upon concave wall 22 causing lt to flex slightly upward and thereby lncrease its circumference. When this occurs, annular interior wall 20 is forced outwardly so that sealing bead 20a presses against the inside surface of container neck 30 to form final seal 28 which is shown in Figures 2 and 5. The higher the pressure rises, the greater the force to form seal 28 thereby insuring that there is no gaseous escape from package 10.
Both the container and cap of this invention may be made by conventional meansD The cap lends itself very readily to pro-duction by injection molding while the container can be made by any one of the many known blowing techniques.
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Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A thermoplastic cap for fitment to a container having a threaded neck, said cap comprising:
a. an annular top wall having a frustoconical inside surface, said inside surface forming a first seal with the outside corner of the uppermost extent of said container neck;
b. an annular sidewall downwardly depending from said topwall and having on its inside surface an inwardly projecting helical thread for cooperation with said container neck thread;
c. an annular interior wall downwardly depend-ing from said top wall, said interior wall displaced radially inward from said sidewall to provide an annular space into which the upper portion of said container neck can nest to form said first seal; and d. a concave wall attached at its circumference to the lower end of said interior wall, said concave wall being flexible for upward flexing in response to internal container pressure whereby said interior wall is pressed outwardly to form a second seal against the inside surface of said container neck when said flexing occurs.
a. an annular top wall having a frustoconical inside surface, said inside surface forming a first seal with the outside corner of the uppermost extent of said container neck;
b. an annular sidewall downwardly depending from said topwall and having on its inside surface an inwardly projecting helical thread for cooperation with said container neck thread;
c. an annular interior wall downwardly depend-ing from said top wall, said interior wall displaced radially inward from said sidewall to provide an annular space into which the upper portion of said container neck can nest to form said first seal; and d. a concave wall attached at its circumference to the lower end of said interior wall, said concave wall being flexible for upward flexing in response to internal container pressure whereby said interior wall is pressed outwardly to form a second seal against the inside surface of said container neck when said flexing occurs.
2. The cap of Claim 1 wherein said outside surface of said interior wall forms a seal with the inside sur-face of said container neck above said second seal.
3. The cap of Claim 1 wherein said cap is made of polyethylene terephthalate.
4. The cap of Claim 1 wherein said cap is made of polypropylene.
5. A thermoplastic package comprising:
a. a container having a threaded neck; and b. a cap having i. an annular top wall having a frusto-conical inside surface, said inside surface forming a first seal with the outside corner of the uppermost extent of said container neck;
ii. an annular sidewall downwardly depend-ing from said top wall and having on its inside surface an inwardly project-ing helical thread for cooperation with said container neck thread;
iii. an annular interior wall downwardly depending from said top wall, said interior wall displaced radially inward-ly from said sidewall to provide an annular space into which the upper portion of said container neck can nest to form said first seal; and iv. a concave wall attached at its circum-ference to the lower end of said interior wall, said concave wall being flexible for upward flexing in response to internal container pressure whereby said interior wall is pressed outward-ly to form a second seal against the inside surface of said container neck when said flexing occurs.
a. a container having a threaded neck; and b. a cap having i. an annular top wall having a frusto-conical inside surface, said inside surface forming a first seal with the outside corner of the uppermost extent of said container neck;
ii. an annular sidewall downwardly depend-ing from said top wall and having on its inside surface an inwardly project-ing helical thread for cooperation with said container neck thread;
iii. an annular interior wall downwardly depending from said top wall, said interior wall displaced radially inward-ly from said sidewall to provide an annular space into which the upper portion of said container neck can nest to form said first seal; and iv. a concave wall attached at its circum-ference to the lower end of said interior wall, said concave wall being flexible for upward flexing in response to internal container pressure whereby said interior wall is pressed outward-ly to form a second seal against the inside surface of said container neck when said flexing occurs.
6. The cap of Claim 5 wherein said outside surface of said interior wall forms a seal with the inside sur-face of said container neck above said second seal.
7. The cap of Claim 5 wherein said cap is made of polyethylene terephthalate.
8. The cap of Calim 5 wherein said cap is made of polypropylene.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US95715678A | 1978-11-02 | 1978-11-02 | |
| US957,156 | 1978-11-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1117478A true CA1117478A (en) | 1982-02-02 |
Family
ID=25499160
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000335781A Expired CA1117478A (en) | 1978-11-02 | 1979-09-17 | Closure cap |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1117478A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4574966A (en) * | 1983-11-07 | 1986-03-11 | Jeffrey Sandhaus | Plastic linerless closure |
| US4714167A (en) * | 1984-11-28 | 1987-12-22 | Jeffrey Sandhaus | Plastic linerless closure |
-
1979
- 1979-09-17 CA CA000335781A patent/CA1117478A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4574966A (en) * | 1983-11-07 | 1986-03-11 | Jeffrey Sandhaus | Plastic linerless closure |
| US4714167A (en) * | 1984-11-28 | 1987-12-22 | Jeffrey Sandhaus | Plastic linerless closure |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |