Bottles and jars – Closures – Cap type
Patent
1993-10-12
1995-06-06
Shoap, Allan N.
Bottles and jars
Closures
Cap type
215343, 215354, B65D 5300
Patent
active
054214700
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a cap sealingly engageable with a container.
The invention is especially useful in relation to the storage of chemicals.
Materials are available for the manufacture of caps economically, for this purpose, the caps having high resistance to corrosion by chemicals. Some grades of polyethylene are well suited to this purpose.
There is a problem, however, in that such materials tend to be too resilient and there is a risk of the cap coming away from a container under the pressure caused when the container is dropped.
It is also important to provide a good seal of the cap in the region of the rim of the mouth of the container, to prevent leakage. It is usual to seal a wad in the cap to the top of the container rim using induction heating techniques. This provides a good seal until the cap has been opened, but the problem of adequate re-sealing then exists.
This form of sealing also creates other problems. It is necessary to cut the wad, which is fixed to the rim of the container, sometimes by means of a cutter in the cap. These often fail to operate successfully and a knife or other implement is often used to open the seal. This substantially increases the risk of spillage or of spreading of the contents of the container by the implement.
A further problem is that a part of the wad, which contains a metal for the induction sealing operation, remains attached to the container. This prevents recycling of the material of the container, due to this contamination.
The primary object of the present invention is to provide a cap having a wad which provides a good non-leakable seal, without the need for induction sealing, the cap being replaceable on the container, after opening, so as to reinstate the non-leakable seal.
It is known to provide caps having wads with resilient annular seals to seal with the rim region of a container, but these have not been adequate for use with dangerous chemicals.
U.S. Pat. No. 4,386,712 discloses a cap having a wad provided with an annular plug for sealing in a container mouth. An annular projection around the plug seals on the top face of the rim of the container. This construction requires accurate matching of the plug to the container, which is difficult to achieve given usual manufacturing tolerances. There is, therefore, risk of the plug fitting too loosely, or of fitting too tightly, so that spillage is likely in trying to remove the cap. The secondary seal is only operative, if the cap is tightly screwed down.
U.S. Pat. No. 3,788,510 also discloses a plug-fitting wad with a wrap-around portion which can be squeezed onto the top surface of the container rim and also squeezed between the skirt of the cap and a recessed outer side wall of the container. This suffers even more from the necessity for accurate dimensioning of the cap, wad and container. There is a risk that, if the wad is slightly overlarge relative to the recess, the wad will not seal properly, or may be damaged. Tight screwing down of the cap would be essential to ensure that a seal was achieved.
GB-A-1199131 also discloses a wad provided with a plug. The wad also has an annular sealing member which seals with a recessed top surface of the container and a ribbed portion which seals on the top surface of the rim of the container. During sealing of the container, the plug is severed from the rest of the wad.
Opening of the container, therefore, is hazardous, since the plug has to be removed from the container as a separate operation. If, as is taught, this is discarded, an inadequate seal remains, if the cap is reapplied.
In all of these prior art documents, and as is well known in the art, the skirt of the cap has an annular projection to retain the wad in the cap.
The present invention avoids the problems of all of these prior art proposals and permits easy removal of the cap and reclosing of the container without loss of the original sealing ability.
The present invention provides a container and cap assembly in which the container comprises a mouth provided with an inner wall, an outer w
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patent: 3370732 (1968-02-01), La Vange
patent: 3568871 (1971-03-01), Livingston
patent: 3788510 (1974-01-01), Collins
patent: 3979004 (1976-09-01), Bertario
patent: 4238042 (1980-12-01), Hatakeyama et al.
patent: 4261475 (1981-04-01), Babiol
patent: 4379512 (1983-04-01), Ohmi et al.
patent: 4386712 (1983-06-01), De Wallace
patent: 4803031 (1989-02-01), Ochs
patent: 5050754 (1991-09-01), Marino
Cronin Stephen
Lawson Mardon Sutton Ltd.
Shoap Allan N.
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