Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D41/00—Caps, e.g. crown caps or crown seals, i.e. members having parts arranged for engagement with the external periphery of a neck or wall defining a pouring opening or discharge aperture; Protective cap-like covers for closure members, e.g. decorative covers of metal foil or paper
  • B65D41/02—Caps or cap-like covers without lines of weakness, tearing strips, tags, or like opening or removal devices
  • B65D41/04—Threaded or like caps or cap-like covers secured by rotation
  • B65D41/0435—Threaded or like caps or cap-like covers secured by rotation with separate sealing elements
  • B65D41/045—Discs

Definitions

• nonreturnable bottle system for carbonated beverages has employed a bottle with an externally screw-threaded neck, having a cylindrical sealing surface between the top of the bottle and the start of the thread.
• a closure in the form of an aluminum shell having a gasket covering the inner surface of the top of the shell which forms a sealing liner.
• the diameter of the skirt of the closure shell is sufficiently large to fit over the thread on the bottle neck at the maximum size allowed by the range of tolerances set out in the specification of the neck finish of the bottle.
• the skirt of this shell is deformed by a thread-rolling operation carried out in known way to bring it into engagement with the thread on the bottle neck.
• thermoplastic material A highly promising alternative to the use of aluminum closures is the use of closures made of thermoplastic material. Such materials are becoming more and more economically favorable when compared to aluminum. Exemplary of such closures is the one shown in U.S. 3,067,900.
• thermoplastic material As desirable as it may be to use thermoplastic material, there is one serious drawback, i.e., the tendency of thermoplastic closures to lose their seal as positive pressure builds in the bottle. Since the seal is made by the closure making sealing contact with the bottle, the loss of seal is generally due to the closure flexing, as the pressure builds, resulting in the closure structure being distorted and pulled away from the bottle. To prevent flexing, it is possible to select a very rigid thermoplastic material.
• thermoplastic closure which is capable of maintaining a seal in response to a positive pressure in a container such as a bottle.
• This invention relates to a thermoplastic closure for fitment to a container having a threaded neck terminating in an open mouth.
• the closure has a circular top wall and a annular downwardly depending skirt, the skirt having about its inside surface a closure thread for cooperation with the neck thread to achieve the fitment desired.
• a circular flexible resilient liner wnich has a diameter greater than the outside diameter of the container mouth.
• annular structure which is located adjacent the inside intersection of the top wall and the skirt. This annular structure has a configuration such that it presses the liner around the outside edge of the container mouth to form a gas-tight seal when the closure is fitted onto the container.
• a retaining ring about the inside surface of the skirt which is positioned below the annular structure but above the closure thread. This retaining ring prevents the liner from moving down to the closure thread. Thus, if the liner should fall away from the top wall the retaining ring will prevent it from being separated from the remainder of the closure.
• an annular tab which projects downward from the top wall. This tab will engage the liner and prevent any lateral movement thereof.
• closure of this invention is not restricted to this theory, that by having the liner wrapped around the outside edge of the container lip a gas-tight seal is maintained even upon upward flexure of the top wall which flexure is caused by positive pressure build-up in the container.
• the closure When the closure is originally fitted to the container there are two principal sealing areas, i.e., there is a seal formed between the liner and the top of the container lip and a second seal formed between the outside edge of the lip and the liner.
• the closure top wall begins to flex upwardly in response to positive pressure in the container the first seal between the liner and the top of the container lip is compromised as the liner is no longer as well supported due to upward flex of the top wall.
• the upward flexing of the top wall increases the fidelity of the second seal as that portion of the liner which is wrapped around the outside edge of the container lip is pressed into a tighter relationship with the outside edge.
• the closure of this invention utilizes the heretofore undesirable flexing of the top wall to increase the fidelity of the seal. This is directly opposite to present-day closures in which the upward flexing of the top wall results in a reduction in seal fidelity.
• the annular structure can have to achieve the above-mentioned seal between the liner and the outside edge of the container lip.
• the annular structure can have a configuration, when viewed in cross-section, which has a horizontal portion, a vertical portion, and a convex portion, the convex portion connecting the horizontal portion and the vertical portion one to the other.
• a concentration of sealing pressure at a point near the center of the convex portion is one in which the annular structure is a convex bead.
• annular structure By utilizing a convex bead the pressure exerted by the annular structure is distributed over a wider area of the liner than is the case with the justdescribed annular structure having the horizontal, vertical and convex portions.
• Another annular structure which can be utilized is one in which the structure is a concave groove having a radius at least equal to the radius of the convex outside edge of the lip.
• the closure of this invention utilizes a liner which is free to rotate with respect to the closure. This freedom to rotate results in the liner being able to achieve essentially a single position on the container lip even though the closure continues to rotate as it is tightened to the container. If the liner was fixed to the closure, the opposite effect would occur as the liner would have to rotate along with the closure as it is tightened to the container. Liner rotation with respect to the container lip results in the liner being rubbed over the lip surface as it rotates with the closure.
• the liner utilized should also be flexible and resilient. Furthermore, since the closure of this invention is to be utilized on either glass or plastic containers, the liner should be made of a material which is compatible with the container to which the closure is attached. For example, liners made of materials which stick to the container lip should be avoided as unscrewing the closure from the container will be difficult and, even if achieved, could result in tearing of the liner. It has been found that liners made of an ethylene vinyl acetate copolymer gives superior results on both glass and plastic containers. Further, such liners are acceptable from a toxicological and odor standpoint when the container is utilized to hold consumable products such as carbonated beverages, beer, etc.
• the container is to hold a non-consumable, other materials may be utilized such as polyvinyl chloride.
• polyvinyl chloride e.g. polyvinyl chloride
• a slip additive such as synthetic wax or fatty amide have been found very useful for this purpose.
• the remainder of the closure can be made of any moldable thermoplastic material which will provide the prior-described characteristics for the top wall of the closure.
• the thermoplastic material should not be so flexible that, under building positive container pres sure, the sidewall of the closure will flex outwardly resulting in the closure threads jumping over the container threads.
• a highly preferred thermoplastic material is polypropylene.
• Other thermoplastic materials which may be useful are polyethylene terephthalate, high density polyethylene, nylon, polyvinyl chloride, etc. Other materials which would be useful are well known to those skilled in the art given the preceding identified criteria.
• Figure 1 is a partial sectional view showing a closure of this invention fitted to a container neck
• Figure 2 is a partial sectional view of the closure shown in Figure 1 under the influence of a positive pressure in the container
• Figure 3 is an enlarged sectional view of a portion of the container and closure shown in Figure 2;
• Figure 4 is a sectional view taken along section lines 4-4 in Figure 1;
• Figure 5 is a sectional view taken along section lines 5-5 in Figure 2;
• Figure 6 is an enlarged sectional view showing a second embodiment of this invention.
• FIG. 7 is an enlarged sectional view showing a third embodiment of this invention.
• a closure generally designated by the numeral 10
• Container neck 8 has about its outside surface adjacent its upper end helical thread 26.
• Lip 15 defines the boundaries of the container mouth.
• the container with which closure 10 is utilized can be made of any suitable material, e.g., glass or a thermoplastic material such as polyethylene terephthalate, polyethylene, polyvinyl chloride, etc.
• Closure 10 has an annular top wall 12 with a sidewall 14 downwardly depending therefrom.
• helical closure thread 16 which is of a design whereby it cooperates with container helical thread 26 to achieve fitment of closure 10 to the container.
• liner 18 In close proximity to top wall 20 there is provided liner 18.
• Liner 18 has a diameter greater than the outside diameter of container neck 8 measured at the container mouth. By having a greater diameter, line 18 will be able to extend around the outside edge 28 of lip 15 to effect the seal of this invention.
• Liner 18 is prevented from moving away from top wall 12 by means of annular ring 24.
• Annular ring 24 may be continuous or discontinuous. Attention is drawn to Figure 5 in which a discontinuous annular retaining ring 24 is shown. Projecting downwardly from top wall 12 there is provided annular tab 22.
• Annular tab 22 has a triangular shape when viewed in cross-section. See Figures 3, 6 and 7. As mentioned previously, annular tab 22 is utilized to insure that liner 18 does not move laterally during the buildup of internal container pressure. Note that annular tab 22 is positioned so that it is over lip 15. By having annular tab 22 so positioned, it is assured that annular tab 22 will obtain a grip on liner 18 by penetration.
• annular bead 20 Located adjacent the inside intersection of top wall 12 and downwardly depending sidewall 14 there is provided annular bead 20.
• An enlarged view of the cross-section of annular bead 20 is shown in Figure 3.
• annular bead 20 has a horizontal portion 21 and a vertical portion 23.
• Convex portion 25 connects horizontal portion 21 to vertical portion 23.
• Convex portion 25 is preferably opposite the outside edge 23 of lip 15.
• annular bead 40 is used in place of annular bead 20.
• Annular bead 40 has, for all practical purposes, no horizontal or vertical portions, but rather is simply a convex bead.
• Figure 7 Another configuration is shown in Figure 7 in which the bead present's a concave profile when viewed in cross-section. This concave bead is labeled 42 and is shown in Figure 7.
• concave bead 42 it is preferable that the outside edge 28 of lip 15 be convex so that liner 18 is nested between concave bead 42 and outside edge 28.
• FIGS 3, 6 and 7 show that the annular beads press against liner 18 to cause it to wrap around outside edge 28 of lip 15.
• top wall 12 is flexed upwards due to pressure in the container the intersection of top wall 12 and sidewall 14 is brought inwardly towards outside edge 28.
• the annular bead since it is integral with the intersection, will also move inwardly towards outside edge 28.
• liner 18 is pressed by the annular bead so that it wraps around outside edge 28.
• the greater the flexure of top wall 12 the greater the inward movement of the before-mentioned intersection and the annular bead, and the further the annular bead is forced to move inwardly the greater the pressure it exerts on liner 18. It can therefore be seen that the seal between liner 18 and outside edge 28 is increased as the pressure grows since the top wall flexes in response to the amount of pressure present.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Closures For Containers (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26913194

Family Applications (2)

Family Applications After (1)

Country Status (7)

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• 1981
  • 1981-12-21 AU AU80835/82A patent/AU544147B2/en not_active Expired
  • 1981-12-21 WO PCT/US1981/001737 patent/WO1982002182A1/en unknown
  • 1981-12-21 EP EP19820900490 patent/EP0067221A1/de not_active Withdrawn
  • 1981-12-21 BR BR8108921A patent/BR8108921A/pt unknown
  • 1981-12-21 JP JP50051182A patent/JPS57501998A/ja active Pending
  • 1981-12-22 CA CA000392976A patent/CA1168621A/en not_active Expired
  • 1981-12-22 DE DE8181306052T patent/DE3177214D1/de not_active Expired - Lifetime
  • 1981-12-22 EP EP19810306052 patent/EP0055916B1/de not_active Expired - Lifetime
• 1985
  • 1985-08-13 AU AU46162/85A patent/AU576885B2/en not_active Expired

Non-Patent Citations (1)

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