Reclosable Can

Abstract

A reclosable container having an annular ring with an inwardly-angled upwardly-extending substantially straight shoulder and a surmounting vertical throat whose interior surface frictionally sealingly engages the outer surface of a vertical to inwardly-tapered friction wall on the container plug to provide a tight closure which minimizes leakage and plug dislodgment upon tipping. The diameter of the base of the friction wall is greater than the throat diameter, and the junction of the plug central panel and friction wall is disposed lower than the junction of the ring shoulder and throat.

Description

BACKGROUND OF THE INVENTION

This invention relates to reclosable containers and more particularly to reclosable single friction and like containers wherein friction in a single area between the container or container ring and lid or plug is largely responsible for closure of the container.

Reclosable single friction containers are useful where a large opening is desirable, as when the product contained therein is one such as paint which is often poured and which must be accessible over a large area to a stirrer or brush. Such containers often have a ring joined to the container body and have a throat defining the opening. The throat usually has a straight portion which frictionally engages a cylindrical friction wall on the plug and thereby effects closure of the container.

It is known that plugs for such containers often do not sufficiently seal the container's contents from the environment and they sometimes allow spillage by becoming dislodged when the containers are tipped during shipping and handling.

It is also known that the throats of such containers are susceptible to permanent distortion when excessive axial force is exerted on the plug, as during closing, shipment and use.

It has now been found that reliable seals, resistant to internal forces exerted on the plug during tipping, and prevention of excessive throat distortion can be obtained by constructing single friction and like containers in accordance with this invention.

BRIEF SUMMARY OF THE INVENTION

This invention is a container comprising a can body, an annular ring and a plug. The annular ring has an inwardly-angled, upwardly extending substantially straight shoulder and surmounting vertical to slightly inwardly-angled throat which can terminate in a curl. The plug has a recessed central panel, preferably flexible and concave, and has an annular vertical to inwardly-angled friction wall adjoining the central panel. The outer diameter of the base of the plug friction wall is greater than the inner diameter of the throat, and the junction of the central panel and friction wall is positioned lower than the junction of the shoulder and throat such that the outer surface of the friction wall fits snugly in frictional sealing engagement with the interior surface of the throat. The junction of the central panel and friction wall can be and preferably is reformed from a previously larger radius. The annular ring can be joined to the can body by means of a conventional double seam and the ring preferably has a substantially U-shaped channel formed by a countersink wall, an arcuate wall and the straight shoulder.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevation of a container made in accordance with the present invention.

FIG. 2 is an enlarged sectional view taken through lines 2--2 of FIG. 1 showing the plug normally seated on the top of the container.

FIG. 3 is an enlarged sectional view showing the plug above the container prior to its being seated within the container throat.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawing in detail, FIG. 1 shows a container generally designated 10, having a container body, 11, closed at one end by a bottom end closure, 12, seamed to the container body by conventional means. As best shown in FIG. 2, an annular ring, 13, is joined to the upper end of can body, 11, by conventional means such as a double seam, 14.

Annular ring 13 includes a countersink wall 15 which forms the inner layer of double seam 14 and, at its bottom end, merges into a substantially U-shaped channel 16 which merges into an inwardly-angled upwardly extending, substantially straight shoulder 18, in turn adjoining and merging into a vertical to inwardly-angled throat 20 which can terminate at its uppermost end in an annular bead or curl 22.

In FIG. 2, a sealing plug generally designated 30, having a recessed, flexible central panel 32 and an annular, vertical to inwardly-angled friction wall 34 is shown seated on container 10 so that the base of plug friction wall 34, adjacent recessed central panel 32 fits snugly in ring 13 with the outer surface of plug friction wall 34 being in frictional sealing engagement with the inner surface of throat 20. Annular friction wall 34 can extend upwardly into, adjoin and merge into an annular curved channel portion 36 which extends outwardly from friction wall 34 and merges with an inclined flange portion 38 which in turn merges with an annular downwardly-projecting skirt 39 which terminates in integral reinforcing bead or curl 40 extending generally outwardly from skirt 39.

FIG. 3 shows plug 30 above and aligned with ring 13 of container body 11 just before being placed thereon to effect the closure shown in FIG. 2.

As shown in FIG. 3, the diameter of plug 30 measured from the outer surface of the base of friction wall 34 is larger than the diameter of ring 13 measured from the interior surface of the base of throat 20. Having a larger diameter at the base of the friction wall is essential for obtaining a proper seal between throat 20 and friction wall 34 and for preventing spillage and dislodgment of plug 30 from the throat. How much larger the diameter must be depends on the gauge and flexibility of the particular type material of which the overall container is made. The diameter must be large enough so that the base of friction wall 34 locks under the junction of shoulder 18 and throat 20 of ring 13. For typical 1 gallon paint containers made of typical steels such as electrolytic tinplate (ETP), 135 lb. gauge plate for ring 13, and 118 lb. gauge plate for plug 30, it has been found that the diameter at the base of plug 30, i.e., adjacent A, must be at least 0.004 inch larger than the diameter at the base of throat 20, i.e., adjacent B.

In order to obtain tight closures, not only must the diameter of the base of plug friction wall 34 be larger than the opening formed by throat 20, but also plug centerline A, (FIG. 2), extending horizontally from the point of the radius, i.e. the center of the circle a portion of whose circumference forms the radius of curvature of the junction of central panel 32 and friction wall 34, must be lower than centerline B, extending from the point of the radius forming the radius of curvature of the junction of shoulder 18 and throat 20. Less precisely stated, the junction of central panel 32 and friction wall 34 must be lower than the junction of shoulder 18 and throat 20. The greater the length of that portion of straight friction wall 34 lying between the respective center lines, the more secure the closure, the greater the number of tips obtainable before leakage or plug dislodgment, and the greater the prevention of distortion of throat 20 due to axial forces exerted on the container. Centerline A should be high enough relative to double seam 14 to permit an opening device to be inserted over the double seam and under plug curl 40 to effect a facile removal of plug 30 from ring 13.

It has been found that for the previously mentioned typical 1 gallon ETP paint can, tight closures are obtained and plug dislodgments prevented, when the distance between centerlines A and B is at least about 0.005 inch.

For the aforementioned container, the length of the radius forming the centerline A, can advantageously be about 0.050 inch. Shorter radii and smaller radii of curvature raise the number of tips obtainable prior to leakage and plug dislodgment. Longer radii tend to be more preventive of throat distortion due to axial forces exerted in the container. For the aforementioned container, when the product contained therein is one such as paint, it has been found that the length of the radius forming centerline B can advantageously be about .040 inch. Radii approaching zero provide increasingly greater abuse resistance.

The radius of curvature forming the plug junction adjacent centerline A is of greater rigidity than the rest of friction wall 34. The junction between central panel 32 and friction wall 34 must be rigid enough to lock the base of plug 30 securely under the junction between shoulder 18 and throat 20. How rigid the junction must be depends among other things on the size container, the gauge metals employed, the length of the radius B, the weight of the product contained in the container, and the number of tips considered to be acceptable before spillage or plug dislodgment occurs. One means of effecting such greater rigidity is by first forming the radius of curvature in a larger diameter, and then reforming it to a smaller diameter. The manner in which this is done is well known to those skilled in the art.

Results of tip tests conducted upon 1 gallon, 6 10/16 inch diameter paint containers constructed with and without reformed radii of curvature adjacent centerline A, are shown in TABLE I, and indicate that reformed radii of curvature give a higher number of tips than formed ones. The tests involved filling containers with from 1 gal. to 1 gal. 9 oz. of water and placing the containers right-side up on a concrete surface. The cans were manually gradually tipped on the edges of their bottom end closures 12, until gravity caused the containers to fall freely on their sides. The container rings were made of 135 lb. ETP and the plugs of 118 lb. ETP. --------------------------------------------------------------------------- TABLE I

Average Type Radius Radius No. of Accept- Radius Dimensions Dimensions Tips able Cl* A CL* B before Plug Ring Leakage __________________________________________________________________________ Formed 0.093 0.040 5 No Do. 0.060 0.040 10 No Do. 0.050 0.040 10 No __________________________________________________________________________ Reformed 0.093 0.040 20 Yes Do. 0.060 0.040 50 Yes Do. 0.050 0.040 50+ Yes __________________________________________________________________________ *CL Centerline

As shown in FIG. 3, when plug 30 is formed, friction wall 34 is vertical to preferably inwardly-angled. Inwardly-angled here means angled towards the central axis of container 10. Otherwise stated friction wall 34 is slightly tapered from bottom to top so that the base adjacent A has a larger diameter than the top adjacent channel portion 36. For the aforementioned container, it has been found that satisfactory closures can be obtained when the angle of friction wall 34 is from 0.degree., to about 1.degree., preferably .5.degree., from the vertical.

Throat 20 of ring 13 also is vertical to inwardly-angled. Although FIG. 2 shows throat 20 as substantially vertical, throat 20, due to characteristics of metals, tends to be effected by the angle of shoulder 18 and tends to take on a slightly inward angle or taper, which is acceptable according to this invention.

Central panel 32 can have a flat, but preferably has a concave profile. Central panel 32 is flexible so that it can flex to the position of the dotted domed profile 32' for example when a filled container 10 is tipped, or when it compensates for increases in internal pressure due to expanding gases such as when the product in the container is an exothermic paint material.

Substantially U-shaped channel 16 need not be so shaped but can be substantially horizontal without significantly affecting the number of tips that can be obtained utilizing the construction of this invention. However, a substantially U-shaped channel is especially advantageous when employed with a short straight portion 16' because together they are especially effective in providing additional strength against forces exerted both radially and axially against the container.

With the construction of this invention, such additional strengths can be obtained dispite the use of light gauge materials. With a substantially horizontal construction, heavier gauge materials are required.

Flange 38, skirt 39 and curl 40 can be of any suitable configuration but preferably they are as shown in the drawing. Skirt 39 can be provided with a series of conventional stop lugs (not shown) extending outward from skirt 39 and overlying double seam 14. When excessive axial forces are exerted on the container for example during initial container closing operations, such stop lugs can abut double seam 14 to prevent such forces from excessively distorting ring 13. The configuration and function of such stop lugs is disclosed in U.S. Pat. No. 3,397,807 issued Aug. 20, 1968.

Claims

We claim:

1. A container comprising:

a metal can body;

an annular ring joined to one end of said can body by a double seam, said ring having a substantially U-shaped channel, said channel being formed by a countersink wall, which merges directly into a substantially arcuate wall, which in turn merges into an inwardly-angled upwardly-extending substantially straight shoulder, said shoulder adjoining a vertical to inwardly-angled throat at an inner portion of said ring above said seam; and

a metal plug, said plug having a recessed concavely-profiled flexible central panel and an annular, inwardly-angled friction wall adjoining said central panel, the outer diameter of the base of said plug friction wall being greater than the inner diameter of said throat, and the junction of said central panel and said friction wall having a reformed radius of greater rigidity than that of its original radius or that of the central panel or inwardly-angled friction wall, said plug junction being lower than the junction of said shoulder and said throat, such that the outer surface of said friction wall fits snugly in frictional sealing engagement with the interior surface of said throat.

2. The container of claim 1 wherein said annular ring is joined to said can body by a conventional double seam, the terminal portion of said throat is curled and said plug has an annular, inverted, substantially U-shaped wall adjoining said friction wall and complementarily sitting in frictional engagement on said throat curl.