US 3151757 A
Description (OCR text may contain errors)
H. A. MARTIN CONTAINER CLOSURE Oct. 6, 1964 2 Sheets-Sheet 1 Filed July 17, 1961 FIG].
1 Yen-fa 2 /21 $1 0071) H. A. MARTIN CONTAINER CLOSURE Oct. 6, 1964 2 Sheets-Sheet 2 Filed July 17, 1961 FIG .4.
United States Patent 0 3,151,757 Q'ONTAEJER CLQSURE Henry A. Martin, Toronto, Gntario, Canada, assignor to Smith Stone Limited, Toronto, Gntario, Qanada July 17, E61, 8er. No. 124,552 Claims priority, pplication Canada May 26, 1961 2 Claims. (ill. 215-41} This invention relates to closures for containers and especially to closures provided with a thread for engaging a corresponding thread on the container.
Although threaded closures for jars, bottles and the like have been in use for a great many years certain problems have arisen in connection with their use which have never been satisfactorily solved and much work has been done on improving the eihciency of such closures, the problem of how to attain a reliable seal between the closure and the container has not been satisfactorily solved in all cases. The closures and containers have to be manufactured by mass production methods and such methods are in go eral not capable of operating economically at low tolerances. The relatively high tolerances which have to be accepted to produce the articles at low cost result in closures which do not accurately fit the necks of the containers with which they are to be used. This is often not particularly important if the containers re intended to hold solid material, which has no tendency to leak through the closure. Sometimes, however, the failure to produce a good seal between the closure and the container may be serious even where the contents are solid. For example, the contents may give off an unpleasant odour or may be impaired in quality by exposure to air leaking into the container.
If the contents of the container are liquid the proble of obtaining a good seal is more acute since it is clearly more dificult to effect adequate sealing of a container which has liquid in it than to seal a container with solids in it. Where the container is accidentally inverted the liquid contents, which are under a hydrostatic pressure due to the head of liquid in the container, can readily leak through any available aperture between the closure member and the neck of the container. Thus, the effective sealing of a container filled with a liquid presents considerable difficulty.
The difiiculty of obtaining an adequate seal is even greater where the contents of the container are such that they are capable of building up pressure beneath the closure member. This is chiefly encountered in the case of volatile liquids or liquids containing dissolved gases. Thus, beverages containing dissolved carbon dioxide are an example of a material for which it is very difiicult to provide a container having adequate seal. In the case of such beverages leakage of the gas through the closure member must be prevented if the beverage is to retain its palatability and precautions are therefore taken to ensure that none of the evolved gas is lost. The closure members used for this purpose, for example of the crown top type, are relatively difiicult to apply to the container and fairly expensive while at the same time being rather unsightly. A simple and more aesthetically pleasing type of closure for use in this field is therefore desirable.
There are other cases where the quality of the material in the container is unimpaired by loss of the evolved gas. It is then desirable to make provision for venting of the evolved gas from the container because no purpose is served by retaining the gas within the container; also the build-up of pressure may be dangerous. However no commercially practical embodiment of a closure member which would allow release of an evolved gas from the container while at the same time providing an effective seal against loss of liquid appears yet to have been devised.
The attempts made in the past to produce leak-proof EJ551757 Patented Get. 6, 1954 closure members have generally involved the use of a liner separate from the body of the closure member and fitting within it. This has required the separate production of a closure member and a liner with subsequent assembly of the two prior to the application of the closure member to a container. Normally the closure member and the liner have been made by different manufacturers of different materials. Since dilferent manufacturers often work to different degrees of precision this has added to the inherent diiiiculties involved in producing a combination of a closure member, a liner and a container which are matched to one another within desired tolerances. Furthermore, although the liner is provided for the purpose of avoiding leakage which tends to occur in a conventionally produced linerless closure member the liner itself has often been a source of leakage due to lack of care in locating the liner within the closure member, irregularities of size or thickness of the liner, the presence of weak or porous spots in the liner, or the swelling, shrinkage or other deterioration of the liner due to the chemical or physical action of the contents on the liner which is frequently of an organic nature. These shortcomings of closure members provided with liners have long been appreciated but there have been no ready ways of dispensing with the liners so that difiiculties associated with their use have had to be borne.
It is an object of the present invention to provide a one-piece closure for containers which is capable of effecting a reliable seal of the container irrespective of the nature of the contents of the container while at the same time being readily manufactured.
It is a further object of the invention to provide a one-piece closure for a container which is capable of providing an effective seal against egress of either gas or liquid from the container.
It is a further object of the invention to provide a onepiece closure for a container which is capable of allowing gas to emerge from the container while at the same time substantially preventing escape of liquid.
The invention provides a container closure comprising a dished member having a top portion, an annular wall extending downwardly from said top portion and a bifurcated sealing member extending downwardly from said top portion within said annular wall, said bifurcated sealing member comprising a primary sealing ring and a secondary sealing ring concentric with said primary sealing ring, said secondary sealing ring extending farther downwardly from said top portion than does said primary sealing ring and being disposed at an angle to said first sealing rin The invention will be described by may of illustration and Without limitation with reference to the accompanying drawings in which:
FIG. 1 shows schematically one embodiment of the invention;
FIG. 2 shows a detail of the embodiment of FIG. 1 on an enlarged scale;
PEG. 3 shows schematically an alternative embodiment of the invention; and
FIG. 4 shows a detail of the embodiment of FIG. 1 on an enlarged scale.
FIG. 1 shows a closure member consisting of a dished member including a top portion 2 and an annular wall 3. The annular wall 3 is formed internally with a screw thread 4 for engagement with a thread 5 formed on the neck d of a container '7. A bifurcated sealing member, concentric with the annular Wall 3, extends forwardly from the top portion 2 within the space enclosed by the annular wall 3 and comprises a primary sealing ring 8 and a secondary sealing ring 9. As best seen in FIG. 2, where the closure member is shown out of contact with the neck 6 of the container 7, the secondary sealing ring 9 extends farther downwardly from the top portion 2 than does the primary sealing ring 8.
The closure member is molded in one piece from a flexible material which may be a synthetic resin, such as polyethylene, although other flexible materials, such as natural rubber, may be used.
The mode of the operation of the closure member will be apparent from a consideration of FIGS. 1 and 2. FIG. 2 indicates the position of the closure member relative to the neck 6 of the bottle 7 as the closure member is being screwed onto the neck 6 but prior to the contacting of the neck 6 by either the primary sealing ring 8 or the secondary sealing ring 9. As the closure member is screwed down, the secondary sealing ring 9 first comes into contact with the upper face 10 of the neck 6. Further screwing down of the closure member exerts pressure on the secondary sealing ring 9 which causes the ring 9 to be deformed. This deformation of the secondary sealing ring 9 continues until the screwing down of the closure member has been continued to such an extent that the primary sealing ring 8 contacts the upper surface 10 of the neck 6. Since the primary sealing ring 8 is, like the remtainder of the closure member, made of flexible material the final tightening of the closure member effects some compression of the primary sealing ring 8.
Thus, when the closure member has been screwed on to the neck 6 as tightly as possible the bifurcated sealing member which comprises the primary sealing ring 8 and the secondary sealing ring 9 serves to effect a double sealing of the container. A primary seal is effected by the primary sealing ring 8 which is compressed against the upper surface 10 of the neck 6 and a secondary seal is effected by the secondary sealing member 9 which presses firmly against the upper surface 10 of the neck 6 due to the fact that it has been considerably deformed from its original position illustrated in FIG. 2. This dual sealing action is achieved regardless of whether the neck 6 is finished with a square corner 11 or a curved corner 1.2.
The closure member of FIG. 1 is effective for sealing containers generally but is especially well adapted for the sealing of a container having liquid contents which are capable of evolving gas to build up a high pressure in the container and where the nature of the contents is such that it is desirable to avoid build up of such pressure by allowing continuous venting of gas from the container although at the same time preventing leakage of the contents. Build up of pressure within the container causes the flexible top portion 2 to bulge outwardly until the point is eventually reached where the primary sealing ring 8 is lifted away from the top surface 10 of the neck 6. As soon as this happens gas is allowed to leak into the space 13 enclosed by the primary sealing ring 8 and the secondary sealing ring 9. This causes a drop in pressure Within the container so that the primary sealing ring 8 is immediately forced downwardly by the resilience of the top portion 2 thereby reestablishing the primary seal effected by the sealing ring 8. A succession of such leakages of gas into the space 13 eventually serves to build up within the space 13 a pressure suflicient to cause leakage of the gas between the secondary sealing ring 9 and the upper surface 10 of the neck 6. In this manner there is thus provided a controlled and continuous venting to atmosphere of gas evolved in the container but leakage of liquid through the closure member is avoided because of the double sealing action. Any small particles of liquid which find their way past the primary sealing ring 8 remain trapped within the space 13 and do not pass through the space of neck 6 and the closure member.
The embodiment of FIGS. 3 and 4 differs from that of FIGS. 1 and 2 in that it is provided with a secondary sealing ring 14 directed inwardly of the primary sealing ring 8 instead of with an outwardly directed secondary sealing ring 9 as in the embodiment of FIGS. 1 and 2. The result is that when the closure member shown in FIGS. 3 and 4 is screwed onto a container as shown in FIG. 3 the secondary sealing ring 14 is deformed so as to lie in pressure contact with the inside edge of the neck 6. This embodiment is especially suitable for use in a case where venting of gas from the container is unnecessary or undesirable. If gas is evolved within a container provided with a closure member as shown in FIGS. 3 and 4 the pressure thereby produced merely serves to improve the sealing action of the closure member since the effect of the pressure is to force the secondary sealing ring 14 more tightly against the inside edge of the neck 6. This sealing action of secondary sealing ring 14 against the inner edge of the neck 6 is effective whether the neck 6 has a square edge 15 or a rounded edge 16.
It will be seen that the embodiment of FIGS. 3 and 4 is well suited for use in closing containers for aerated beverages and the like where escape of gas from the container is to be avoided.
As will be noted from the above description the invention enables the production of a one-piece molded closure member which is capable of effecting a double sealing action when applied to a container. The elimination of the separate liner member used in conventional closures simplifies production techniques, minimizes possible contamination of the contents of the container by the material of the liner, permits uniform torque to be used for applying the closure to the containers (this is especially important Where the closures are to be applied to the containers by mechanical devices) and provides a seal which is not susceptible to change or deterioration because of the effect of the contents of the container on the material of the closure member.
By the use of a bifurcated sealing member providing a secondary sealing ring disposed at an angle to a primary sealing ring it can be ensured that the secondary sealing ring is capable of a large amount of deformation during the screwing of the closure member onto the container. As a result, an effective secondary seal is initiated prior to the contacting of the primary sealing ring with the neck of the container and is reinforced during the subsequent deformation of the secondary sealing ring. This means that even if the primary seal is at any time broken (as by lifting of this seal under the action of pressure within the container) the secondary seal will remain in force. To obtain a high degree of deformation of the secondary sealing member and hence a high sealing pressure, it can be arranged that the deformation commences immediately upon engagement of the threaded portion of the closure member with the threaded portion of the container. In view of the fact that the functions of the primary sealing ring and secondary sealing ring are different it is desirable to make the primary sealing ring of greater thickness than the secondary sealing ring. The seal effected by the primary sealing ring is due to compression forces whereas the seal effected by the secondary sealing ring is due to tension forces so that the secondary sealing member is preferably more flexible than the primary sealing member.
It will be appreciated that the closure member of the invention is primarily applicable to cases where the closure member is to be provided with a thread for cooperation with a thread on the container to be closed. However there are types of specialty containers in which the closure member is secured to the container body by means other than the cooperation of screw thread and the invention is also applicable to such cases.
Various modifications are clearly feasible with the scope of the invention. It would be possible to utilise a sealing member provided with more than one secondary sealing ring. For example the sealing member could include a primary sealing ring, an inwardly extending secondary sealing ring and an outwardly extending sealing ring. Alternatively two secondary sealing rings could extend from the same side of the primary sealing ring each at a difierent angle thereto to provide an overlapping secondary seal. In these specific embodiments the sealing member would be trifurcated. For this reason, the word bifurcated is used in this specification and in the appended claims to cover a sealing member providing at least two, but optionally more than two, sealing rings. Preferably one of the sealing rings extends substantially parallel to the outer annular wall of the closure member so as to effect a primary seal under compression forces but if desired each of the sealing rings may be at an angle to the annular wall to effect a seal under tension forces.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A container closure comprising a cylindrical member with a circular flat top portion and a depending wall extending downwardly around the perimeter of said top portion, said wall being internally threaded for screwing onto corresponding threads of a container to be sealed, a concentric sealing member depending from the lower surface of said top portion, said sealing member being spaced radially inwardly of said wall for sealing on the edge of a neck of a container, said sealing member being bifurcated and comprising a primary sealing ring member substantially rectangular in vertical cross-section, and a secondary sealing ring member of substantially less thickness than said primary ring member and extending outwardly from the outer wall of said primary ring member at an acute angle with respect thereto, to form a V-shaped annular space between said ring members, said secondary ring member being substantially longer than said primary member and extending vertically a distance beyond the lower end of said primary ring member, said container closure being formed of resilient plastic material and formed of a single piece.
2. A container closure comprising a cylindrical member with a circular flat top portion and a depending wall extending downwardly around the perimeter of said top portion, bottle engaging means on said wall for securing the closure onto a container to be sealed, a concentric sealing member depending from the lower surface of said top portion, said sealing member being spaced radially inwardly of said Wall for sealing on the edge of a neck of a container, said sealing member being bifurcated and comprising a primary sealing ring member substantially rectangular in vertical cross-section, and a secondary sealing ring member of substantially less thickness than said primary ring member and extending out of the side wall of said primary ring member at an acute angle with respect thereto, to form a V-shaped annular space between said ring members, said secondary ring member being substantially longer than said primary member and extending vertically a distance beyond the lower end of said primary ring member, said container closure being formed of resilient plastic material and formed of a single piece.
References Cited in the file of this patent UNITED STATES PATENTS 2,768,762 Guinet Oct. 30, 1956 3,010,596 Williams et al Nov. 28, 1961 3,053,406 Wandell Sept. 11, 1962 FOREIGN PATENTS 1,060,557 France Nov. 18, 1953 1,226,696 France Feb. 29, 1960