US3392873A

US3392873A - Seal for a tobacco container

Info

Publication number: US3392873A
Application number: US482374A
Authority: US
Inventors: Jr Jonathan W Old
Original assignee: Liggett and Myers Tobacco Co
Current assignee: Liggett Group LLC
Priority date: 1965-08-25
Filing date: 1965-08-25
Publication date: 1968-07-16
Anticipated expiration: 1985-07-16

Description

July 16, 1968 J. w. 01.0. JR

SEAL FOR A TOBACCO CONTAINER Filed Aug. 25, 1965 Tic E.

h O J E T N NL 1 A N M m 3 w 7 .H kw Q82 fl Z 1 w 2 fi////// I] A (5 2 v B w 4 (5 m flu Wm--. 1! y W United States Patent 3,392,873 SEAL FOR A TOBACCO CONTAINER Jonathan W. Old, Jr., Greenwich, Conn., assignor to Liggett & Myers Tobacco Co., New York, N.Y., a corporation of New Jersey Filed Aug. 25, 1965, Ser. No. 482,374 16 Claims. (Cl. 220-60) ABSTRACT OF THE DISCLOSURE The cap is formed with a pair of spaced depending flanges to engage two spaced sealing surfaces with the formation of an entrapped volume of air between the seals. The cap bulges at its center to exert a force on the inner flange to press it against the inner sealing surface.

This invention relates to the provision of a seal on a tobacco container, and more particularly to a construction which achieves two barrier seals between the inside and the outside of a tobacco container, each of these seals being confined to a narrow sealing area circumference and each being maintained under pressure.

The problem of providing a simple yet effective cap for a rigid container is an old one. Vast sums have been spent to perfect the ideal cap, and a great many constructions are known to the art, see for example the following patents, and the references cited therein: Earl S. Tupper 2,487,400; Edward C. Hicks 2,546,599; Donald W. Hill 2,606,586; Kenneth E. Rosenlof 2,630,237; William J. Poole 2,638,261; Nathan W. Roop 2,695,115; Earl S. Tupper 2,802,590; Earl S. Tupper 2,901,098; Earle H. Barclay 2,990,998; Grant S. Gilbert 2,997,788; Earl S. Tupper 3,044,611.

There has remained the need, however, for a cap that could be easily and cheaply manufactured, be used on standard containers, be sufficiently rigid to give a goo-d packaging appearance and hold the shape of copy or artistic design, and still provide a superior gas and moisture vapor barrier.

The problem has been particularly acute in the tobacco container art. Pipe tobacco must have a certain moisture content. This moisture is easily lost to the atmosphere through evaporation. The problem is critical because pipe tobacco, unlike usual foodstuffs, frequently sits for long periods of time on the shelf before it is sold and yet the consumer is very conscious of whether or not it is stale, or dried out. Moreover, even after it is sold, the tobacco is often taken from the can in small amounts, the cap being removed and replaced after each use. Consequently, the cap must be capable of convenient removal and replacement, and yet it must make a good seal each time. The problem of providing an adequate seal has been so severe that some manufacturers have felt compelled to use solid metal containers and caps for pipe tobacco, even though this entails a considerable expense.

It is an object of the present invention to provide an inexpensive and easily manufactured plastic cap which can be used with conventionally manufactured cans to provide a superior vapor resistant seal that will meet the standards for tobacco storage.

Further objects and advantages of the invention will be apparent from the following more detailed description in which:

FIG. 1 is a side sectional elevation of a tobacco container according ot one embodiment of the invention;

FIG. 2 is a side sectional view of a tobacco container ice cap according to one embodiment of the invention; and

FIG. 3 is a partial detail view of a container and cap assembly.

According to the present invention, two separate seals are separately made against the can which co-operate to provide the vapor barrier. These seals must be widely spaced from one another and the cap should be free from the can in the area between the seals so as to be able to flex in and out slightly and thus maintain pressure on the inner seal as explained below.

Preferably, volume is enclosed between cap and can in the space between the inner and outer seals. It is thought that the cap and can when constructed to enclose such a volume are effective partly becauseto the extent that any gas or vapor circulates in and out past the inner sealany vapor that circulates past the inner seal tends to be trapped in the enclosed volume between the inner and outer seals and thus tends to circulate back into the can. This recapture of a portion of the vapor that is displaced past the inner seal, while a small effect, may be significant when compared to the small total of (net) leakage that can be tolerated. The recapture volume is shown generally at 21 in FIG. 3.

In particular, a tobacco container or can or canister 1 is manufactured with any suitable method and material and to any desired shape, except that the areas in which the two seals are to be formed must be made so that each of the sealing areas is of a hard smooth material, so that each of the sealing areas is substantially separated from the other, so that there is a retaining edge or lip below or forming a part of the outer sealing area, and so that the portion of the container or canister between the two sealing areas is depressed or otherwise constructed (in relation to the cap to be used) so as not to interfere with the cap in the sealing action that is hereinafter described. In the particular embodiment shown in FIG. 1, an outer sealing area circumference is provided at 2, a retaining edge 3 is provided adjacent and as a lower part of the sealing area, an inner sealing area circumference is provided at 4. The inner sealing area 4 must be spaced from the outer sealing area 2 by a vapor-tight portion 5 of the can. This portion may be of any convenient construction or container contour except that it must be depressed or otherwise made so as not to engage the cap in the area intermediate the two sealing areas. Preferably, a metal crimp or flange is shaped to provide the outer sealing area circumference 2, the retaining edge 3, and the inner sealing area 4 and the depressed vapor barrier portion 5. This flange may be crimped to the can side walls, 6, or otherwise attached.

The cap 7 is constructed to provide a downwardly projecting outer flange 8 and a downwardly projecting inner flange 9 joined at their upper ends by a portion 10' of the cap construction.

According to the present invention, the cap is made of a semi-rigd material with some elasticity. A high degree of forgiveness allows the cap to shape itself to the can despite some manufacturing variations. A preferable material is low density polyethylene, for example, a polyethylene having a density of .9 gram per cubic centimeter and available for molding with a melt index of 30. The elasticity or resilience of the cap is necessary to provide for the action of the seals as hereinafter described. Other plastics with similar characteristics may be used.

The flange 8 is provided with a lower interlocking projection portion 11 which is designed to underlay the retaining edge 3 on the can when the cap is in position. The outer seal portion 12 of the flange 8 intermediate the top portion and the retaining projection 11 is dimensioned so that when the cap is in its normal relaxed condition before being applied to the can, the diameter of the inner surface 12 is slightly less than the diameter of the outer sealing area 2 on the container. Preferably these two areas are made so that the sealing area will be relatively narrow and even approach a line contact. This achieves a higher pressure per square inch and provides a better seal.

The inner surface 13 of the downwardly projecting inner flange 9 is made so that with the cap in a normal relaxed position and before being applied to the can the surface 13 will have a diameter slightly greater than the diameter of the inner sealing area circumference 4 provided on the can. The flange 9, being of the same material with the rest of the cap will have a small amount of resilience and flexibility. Preferably the sealing surface 13 is made so that when it is placed downward by the can surface 4, it is deflected inward. This may be accomplished by an inwardly downwardly slope of the surface 13, especially at 15.

When the cap made as described above is placed on a can as described above, the two seals are formed as follows.

The cap is placed on the can by putting it over the can and pushing the outer. circumference down around the edge of the can.

The outer seal is formed as the outer downwardly projecting flange 8, with its retaining lip 11, is stretched and pushed over the outer sealing area 2 so that the retaining lip 11 on the cap snaps under the retaining edge 3 on the can. Then, and in position, the intermediate inner surface 12 of the outer flange is in firm contact with the outer sealing area circumference 2 on the can to form an outer seal. Also, the cap is restrained about its outer circumference from upward movement off the can by the interaction of retaining edge 3 and retaining lip 11.

The inner flange 13 on the cap encounters the upper corner portion 14 of the inner sealing area circumference 4 of the can. The portion of the inner flange that makes this contact, for example as indicated generally at 15, is sloped or curved so as to cause a deflection of the flange inward and allow the face 13 to slide down adjacent to the inner sealing area 4 on the can. The surface 13, which preferably is made with a slight incline when in relaxed condition, inclines further as its lower portion is flexed inward. Preferably the upper inner portion 14 on the can flange is lower than the top 17 of the upper outer portion to help allow the flange 9 to flex past the sealing surface 14. The surface 13 is also inclined further as the portion of the cap 10 and the outer flange 8 of the cap are bent downward with respect to the portion of the cap 10 over the inner flange 9 during installation of the cap. In effect, this upward bulging of the central part of the cap tilts the inner flange 9 inward. It should be understood that the amount of incline and flexing may be very small, since the dimensional variations being compensated for may also be very small.

It can be seen that elasticity in the cap portion 10 intermediate the outer and

inner flanges

8 and 9 contributes to the flexing of the flanges, particularly the inner flange, and to the ability of the cap to form a reliable seal on the can despite the slight variation in dimension of the sealing surfaces occasioned by normal manufacturing tolerances, especially those encountered in the plastic molding of the cap. Moreover, it should be understood that the semi-rigid plastic material of the cap and the rigid, preferably metal, material of the can have different coeflicients of expansion. Even if the fit is perfect at normal room temperature, it will loosen and tighten as it is exposed to the ranges of temperature experienced in the course of shipment and storage.

Or the inner sealing area 1 on the can may be slope or curved at 14.

Specifically, as the outer and retaining lip of the cap is shoved on the can, a portion 10 of the cap is deflected upwardly by the relatively upward thrust of the flange 9 as resistance to its downward movement is generated by its action against the can surface 4. This deflection produces a downward spring-like pressure which urges the slightly inclined, tilted and flexed inner flange 9 against the sealing area 4 and this spring pressure provides considerable compensation for variations in fit by pressing the flange further down if it is a relatively loose fit or, remaining somewhat deflected upwardly if it is a relatively tight fit. This degree of deflection of the top does not interfere with the appearance or general serviceability of the cap, but it does provide for always forming a seal on the inner flange. It should be understood that the deflections may be greater or less than is shown in FIG. 3. If the manufacturing tolerances, the differences in coeflicient of expansion or the rigidity of the cap material require, the outer surface of the inner flange 9 can be angled slightly inwardly away from the point 16 where the surface intersects the top portion of the cap 10. This achieves a greater lateral component of surface 13 movement toward the inner sealing area 4 on the can as the inner flange 9 is moved downwardly than is otherwise achieved by such downward movement.

It is possible to manufacture a cap and can construction that provides a double seal or vapor barrier by various techniques that can be employed in a factory. A double seal barrier for tobacco cans must be one that can be repeatedly made in the home for it will be appreciated that tobacco is used from tobacco cans a little bit at a time and that it is critical for the double seal barrier to be re-established after each pipe or pouchful of tobacco is removed from the can. The present construction provides a cap that will form the double seal with only gentle hand pressure being used to press the outer flange down over the retaining lip about the can. This ease of assembling cap and can is also, of course, advantageous in manufacturing.

In view of the illustrated embodiment of the invention, other forms will be apparent to those skilled in the art.

I claim:

1. In combination with a can having an outer sealing area circumference, a separate inner sealing area circumference spaced from said outer sealing area circumference, and an outer retaining edge; a cap having a top portion; a downwardly extending outer flange, the inner surface of said outer flange dimensioned so that with the cap in a normal relaxed condition it is slightly smaller than the dimension of the outer sealing area circumference on the can, said outer flange having at the bottom portion thereof an inwardly extending retaining lip adapted to engage the outer retaining edge on the can; and a downwardly projecting inner flange, the outer surface of said inner flange being dimensioned so that with the cap in a normal relaxed condition it is slightly greater than the dimension of the inner sealing area circumference on the can and disposed on a downward inward slope.

2. A cap and can assembly having an outer seal formed by an outer circumferential sealing area about the can adjacent an open end thereof in co-operation with an overlying circumferential sealing area about the inner surface of a flange projecting downwardly from the top of the cap and having an inner seal formed by an inner circumferential sealing area about the can adjacent the same said open end thereof, said inner circumference sealing area on the can being spaced from said outer circumference sealing area on the can, in co-operation with a circumferential sealing area on an inner flange projecting downwardly from the top of the cap, and overcomeable axial restraining means holding the cap from axial displacement off the can.

3. The assembly of claim 2, supra, in which said inner circumferential sealing area circumference about the can is displaced inwardly from the said open end of the can to which it is adjacent.

4. The assembly of claim 2 in which said axial restraining means comprise an outer restraining edge on the can and a retaining lip on the cap for engagement therewith.

5. A cap and can assembly having an outer seal formed by an outer circumferential sealing area about the can adjacent an open end thereof in co-operation with an overlying circumferential sealing area about the inner surface of a flange projecting downwardly from the top of the cap and having an inner seal formed by an inner circumferential sealing area about the can adjacent the same said open end thereof, said inner circumference sealing area on the can being spaced from said outer circumference sealing area on the can, in co-operation with a circumferential sealing area on an inner flange projecting downwardly from the top of the cap, and overcomeable axial restraining means holding the cap from axial displacement olf the can, the portion of the top of the cap above the inner flange being deflected upwardly with respect to the area of the cap over the outer flange, relative to their respective positions when said cap is in a normal relaxed condition so that there is generated a downward spring pressure urging the circumferential sealing area of the said inner flange against said inner circumference sealing area on the can.

6. A cap and can assembly having an outer seal formed by an outer circumferential sealing area about the can adjacent an open end thereof in co-operation with an overlying circumferential sealing area about the inner surface of a flange projecting downwardly from the top of the cap and having an inner seal formed by an inner circumferential sealing area about the can adjacent the same said open end thereof, said inner circumference sealing area on the can being spaced from said outer circumference sealing area on the can, in co-operation with a circumferential sealing area about the outer surface on an inner flange projecting downwardly from the top of the cap, said sealing area on said inner flange being inclined parallel to a cone having its apex on the inward side of said cap, and overcomeable axial restraining means holding the cap from' axial displacement off the can, said means including an outer restraining edge on the can and a retaining lip on the cap for engagement therewith.

7. -A cap adapted for closing a can having an outer sealing area circumference adjacent one end, an inner sealing area circumference spaced from the outer sealing area circumference and a depressed vapor barrier portion connecting the outer and inner sealing area circumference; said cap having a circular top portion being substantially flat when in relaxed condition, a downwardly projecting outer flange dimensioned to a stretch fit about the outer sealing area circumference of the can, means for retaining said outer flange on said can against forces applied inwardly of said outer flange, a downwardly projecting inner flange having a surface thereon with a portion thereof inclined downwardly inwardly from said top portion into the can, said inner flange having a base where said surface joins the underside of said top portion dimensioned slightly larger than the dimension of the inner sealing area circumference on the can and a bottom portion of said surface dimensioned slightly smaller than the inner sealing area circumference on the can whereby when said cap is in position on the can the intermediate portion of said surface of said inner flange engages the inner sealing area circumference of the can causing an upward deflection of said top portion and a reactive downward spring pressure force holding the surface of said inner flange against the inner sealing area circumference of the can.

8. The cap of claim 7 in which the means for retaining the cap and thereby the top from being removed from the can by force applied inward of said outer flange comprises a retaining lip about the lower end of the outer flange on the cap extending inwardly of said outer flange and adapted to engage an edge on the can.

9. The cap of claim 7 in which a leveling flange is provided on the top side of the top of said cap, said leveling flange located adjacent to the outer edge of the top, so that when the portion of the top above the inner flange is deflected upwardly when the cap is installed upon the can, the flange top remains above the top of the cap and continues to provide a flat surface so that the cans may be stacked on on another without tipping.

:10. The cap of claim 7 in which the cap portion intermediate the downwardly projecting outer flange and the downwardly projecting inner flange is constructed to enclose a recapture volume lying intermediate the cap, the can and the two seals when the cap is installed on said can.

11. A cap and can assembly having an outer seal formed by an outer circumferential sealing area about the can adjacent an open end thereof, said outer can sealing area having a retaining portion thereof facing away from the open end of the can, said outer can area being in co-operation with an overlying circumferential sealing area about the inner surface of a downwardly projecting flange from the cap, said cap inner surface being shaped to overlie both the outer sealing circumference and the said retaining edge portion thereof on the can whereby a greater pressure within the cap and can assembly than without it will result in an increase of pressure experienced by said outer seal, an inner seal formed by an inner circumferential sealing area on said can in co-operation with an outer circumferential sealing area on a downwardly projecting inner flange from said cap, said inner surface on the inner flange of said cap having in position on the can a downwardly inwardly incline such that a greater pressure outside the cap and can assembly than within it will cause an increase in pressure on said inner seal.

12. A one-piece cap for forming a seal including a flat top,

a first annular flange depending from said flat top and having a retaining lip at the lower end thereof facing inwardly of said flange and a smooth outer wall surface facing outwardly of said flange, and

a second annular flange depending from said flat top inwardly of said first flange and in spaced relation to said first flange.

13. A one-piece cap for forming a seal including a flat top having a bottom planar surface,

a first annular flange depending from said bottom planar surface of said top, said flange having a retaining lip at the lower end thereof facing inwardly of said flange and a smooth uninterrupted outer cylindrical wall surface, and

a second annular flange depending from said bottom planar surface of said top, said second flange being spaced inwardly of siad first flange.

14. In combination,

a container having a first sealing area, and a second seaaling area spaced inwardly of said first sealing area; an

a cap having a top disposed over said container, said top being flat in normal relaxed position and having a bottom planar surface, a first flange depending from said bottom planar surface of said top in sealing contact with said first sealing area and a second flange depending from said bottom planar surface of said top inwardly of said first flange in sealing contact with said second sealing area, said top having a central part bulging upwardly from said container out of said normal relaxed position to maintain a force on said second flange against said second sealing surface.

15. The combination as set forth in claim 14 wherein said container further has a retaining edge below said first sealing area and said cap further has a retaining lip on said first flange in manually removable engagement with said retaining edge.

16. :In combination,

a container having a first sealing area, a second sealing area spaced inwardly of said first sealing area, a re taining edge below said first sealing area, and a de- References Cited pressed area between said first and second sealing areas; and UNITED STATES PATENTS a cap having a tOp disposed over said can, a first flange 3,25 17 19 Gran 220 0 depending from said top in sealing contact with said 5 3 232,477 11 9 Henchrt 22 first sealing area and having a retaining lip thereon 3 244 354 4 1956 Bauer 220 42 in releaseable engagement with said retaining edge to 3 2 9,5 1 19 Ruckberg N 2 y 0 hold said cap on said container, and a second flange 3 297,193 1 19 7 Stevens 22 depending from said top inwardly of said second seals 3 said p avi g a central p gi g p- THERON E. CONDON, Primary Examiner. war y rom said container to tilt said second ange inwardly while maintaining a resilient force on said DONALD NORTON Emmi/my second flange against said second sealing surface. G. T. HALL, Assistant Examiner.