US2408465A - Container cap - Google Patents

Description

' Oct. 1,1946. LAUVE 2,408,465

CONTAINER CAP Filed May i, 1942 2 Sheets-Sheet 1 .L. L. LAUVE I CONTAINER CAP Filed May 1, 1942 2 Sheets-Sheet 2 LguisL.Lauv,e,

Patented Oct. 1, 1946 UNITED STATES PATENT orFicE .QQNTAINER CAP Louis L. Lauve, Baltimore, Md., assignor to Crown Cork & Seal Company, Inc., Baltimore,

Md., a corporation of New York Appl cation May 1, 1942, Serial No. 441,357

I I 4 Claims.

This invention relates to container caps of the type designed for snap-on and pry-ofi 'coaction with a peripheral locking ring of a container, and

is an improvement on the closure of. Such type disclosed in Patent N0. 2,109,805, granted March 1, 1938, to Robert J. Stewart.

The said patent discloses, in particular, a skirted metal cap having six equi-distantly spaced i -pressed lugs in the skirt, the internal diameter of the skirt being sufficiently greater than the maximum diameter of the container locking ring or bead so that upon application or removal of the cap the skirt portions intermediate the lugs can flex temporarily inwardly, e.., straighten somewhat, whereby the skirt portions at the lugs are enabled to flex outwardly to release the lugs without ole-formation, thereof. A cap which is re-usable many times with substantially original locking efliciency is thus provided. 7

While the eap of the Stewart patent is entirely satisfactory in use so far as sealing efficiency is concerned, the considerable number of lugs (six) renders the cap rather difficlllt to remove, particularly when the lugs are formed in the curled lower edge of the skirt. One, reason for this is that when the pry-oil tool is applied atany point under the cap edge and leverage is exerted, lugs immediately adjacent the point of leverage application tend to be drawn under the locking ring of the container and so resist the tiltingoff of the cap, That is to say, while the skirt portions at the lugs should flex outwardly to facilitate removal and avoid lug deformation, the outward component of the force exerted on the cap by the I pry-on tool results in a stretching effect toward the tool which resists outward flexing of the skirt portion, thus opposing the outward camming of the skirt portion by the lugs which are adjacent the tool.

It is stated in the patent that as few as three lugs may be used, and while this is so in many situations, a three lug cap may fail where high internal pressures are encountered. Further, as to the six lug cap, it might be supposed that case of removal would be facilitated by easing the top angle of the lugs somewhat into the skirt thereabove, as compared tothe rather abrupt top angle disclosed in the patent. This, however, does not overcome the above described tendency for the lugs adjacent the point of leverage application to pull under the locking ring in resistance to the outward eammihg action enforced by the movement of the lugs upwardly across the locking ring. For another thing, if the tops of the lugs are run. upwardly into the skirt at too wide an angle, the

radial component at the lugs, with the cap applied, may be such that the top of the cap thereabove will be distorted upwardly, thereby impairing the seal between the cap and the container lip just .above the lugs.

I have discovered that a cap which will afford an effective seal and willyet have satisfactory removal characteristics, results when its skirt is provided with a small number of twin lug formations or dents, the lugs preferably starting in a curled edge of the skirt, running at a rather wide angle into the skirt above the curled edge, and being shaped for point contact with the locking ring when applied. The lug-s of each twin lug formation are preferably spaced as closely as possible with respect to each other without subjecting the skirt to destructive bending stresses in manufacture. By the provision of these twin lugformations, each formation providing; a double point contact with the locking ring, a'cap having three such formations will, of course, have the same number of gripping points as a cap having six equi-distantly spaced lugs. However, the angular extent of the free arcs between two adjacent lug formations is substantially greater than that between adjacent lugs ofa six lug cap whose lugs are equidistantlyspaced, and these longer arcs can more readily flex toward the locking ring in cap removal or application. As compared to a cap having three equi-distantly spaced single lugs, the lugs of the twin lug formations may be merged into the skirt at a wider angle for the facilitation of cap removal.

In the accompanying drawings, I have shown two variants of the invention by way of example and the description will proceed with reference Y to these drawings in which:

' Figure 4, but in a different relationship.

Figure 6 is an enlarged outside fragment of the cap of Figure 1 in elevation.

Figure? is an enlarged inside fragment of the cap in Figure l in elevation.

Figure 8 is a view like that of Figure 4 showing a slightly modified form of lug.

Figure 9 is a bottom plan view of a cap in accordance with the invention with lug formations of modified design.

Figure 10 is an enlarged fragmental section on line iii-40 of Figure 9, including a portion of a container to which the cap is applied.

Figure 11 is an enlarged fragmental section on line lL-H of Figure 9 and adjacent container portion.

Figure 12 is an enlarged fragmental section on line i2i2 of Figure 9 and adjacent container portion.

Figure 13 is an enlarged outside fragment of the cap of Figure 9 in elevation.

Figure 14 is an enlarged inside fragment 0 the cap of Figure 9 in elevation, and

Figure 15 is a section on line i5l5 of Figure 13.

The cap shown in Figures 1 to 7 is formed of the usual resilient sheet metal and comprises a circular solid top portion 2| and a substantially cylindrical depending skirt 22 having at its lower edge a continuous outwardly curled or rolled edge 23. An annular gasket 24, preferably of material such as semi-vulcanized rubber, is adhered to the under surface of the cap top and the latter, as shown, is provided with a circular top indentation 25. Reference numeral 26 designates a container, here shown as being a glass jar, the container having a mouth 21, an angular lip 28 adapted to engage the gasket below the circular indentation 25, a continuous external locking ring or bead 29, and a pry-off ledge 30 which is appropriately spaced below the edge 23 when the cap is applied to the container as in Figures 1, 3 and 4. With normal tolerances, the internal diameter of the skirt is materially greater than the maximum diameter of the ring 29, as seen in Figure 3.

The skirt 22 is provided with three equi-distantly spaced twin lug formations, each of the said formations comprising two lugs 3| and 32 struck inwardly in the curled edge. As seen in Figure 4, for example, each lug is of generally flat V-section in a bisecting axial plane and has a lower portion 33 in the curled edge inclined downwardly and outwardly from the apex 34 and an upper portion 35 inc1ined upwardl and out wardly and merging into the skirt portion above the curled edge at an angle of about 30. The lower and upper portions of the lugs afiord a shoe horn eifect in the cap applying and removing operations, respectively, easing the lugs across the locking ring in either direction. The circle tangent to the apices 34 of the lugs has a diameter appropriately smaller than the maximum diameter of the ring 29. As seen in Figures 4 and 5, the curled edge is somewhat fiattened at the lugs, but this is merely incidental to the forming operation.

It will be noted that the outer extremity of the edge portion 23' between the lugs 3| and 32 is tangential to the outer circle of the edge 23 so that the lugs are well defined. Ordinarily, these lugs are placed as closely together as is possible without; subjecting the skirt to destructive bending stresses in manufacture. The lugs are substantially arcuate, perhaps approaching a V, in a sectional plane normal to the cap axis so that during application to the container the lugs have line contact with the ring 29 and point contact when in finally applied relation. The inward curves of the lugs in the curled edge clearly appear in Figure 2, adjacent ends of the curves of the lugs of each set being immediately joined by an outwardly curved portion 23.

The inclination at 33 of the lugs and the diameter of the circle tangential to the lower extremities of the said portions are such that when the cap is set on the container, as in Figure 5, pressure applied to the top of the cap will cause any lug formation above the ring to be cammed readily radially outwardly as the lugs move downwardly across the ring, the uninterrupted or unmutilated arc portions 36 of the edge 23, between the lug formations, straightening somewhat during this operation so as to avoid or minimize the deforming effect on the lugs. With normal tolerances, the spacing between the locking ring 29 and the arc portions 36 is such that when the apices 34 are on the maximum circle of the ring 29 the center portions of the arcs will not quite touch the ring. As the apices pass below the maximum circle of the ring the inclined portions 35 exert a camming action as the lugs and the arc portions 36 resume substantially their original relationship, and gasket 24 is drawn forcibly against lip 28 so that the latter is substantially embedded in the gasket as shown in Figures 3 and 4.

Due to the double gripping points provided by each of the twin lug formations, the cap is held securely on the container, but due to the localization of the gripping zones, and also to the relatively easy angle of the upper lug portions 35, the cap can be readily removed by a prying tool and this without danger of damaging the locking ring. In view of the outward spacing of the cap skirt from the locking ring, the portions 35 of the lug will always be sufficient to take care of minimum tolerances in the locking ring. The apices 34 should be sumciently low to permit the portionsv 35 to accommodate maximum tolerances of the locking ring, it, of course, being necessary in all cases that the portions 35 engage below the ring for locking effect.

The angle of the upper portion 35 may be varied somewhat and in Figure 8 the corresponding portion 35 has an angle of around 20. The angle should not be so slight and run so far up into the skirt as to give too much of a radial component, since, as has been mentioned, in such case the cap will tend to lift just above the lugs so that the seal at these points is apt to be impaired.

It may be mentioned that Figures 1 and 2 show a cap in a substantially exact commercial size, the inside diameter of the skirt being about 2 /4 inches with the circumference thus slightly over seven inches. The engaging points of the lugs of each lug formation are substantially one-half inch apart, this spacing enabling the lugs to be formed without danger of damaging the skirt metal. The same spacing of the twin lugs can be maintained in caps of larger diameter. The distance between adjacent sets of lugs is always at least twice the distance between the contact points of the lugs of each set. In the example shown in Figures 1 and 2 the distance between the lugs of each set is about /14 of the circumference.

If it is desired to space the lugs of the twin lug formations more closely, the design shown in Figures 9 to 15 may be used. According to this modification, the twin lugs 31 and 38 are in effect substantially the same as before, but the portion 35 of the curled edge between the lugs terminates outwardly substantially within the outer curve of the full arc portions of the edge. Since there is less extreme bending of this portion 39 as compared to the portion 23' of the first embodiment,

the adjacent lugs can be substantially closer together without danger of injury to the metal in manufacture. The lugs 25! and 38 are somewhat sharper, i. e., more nearly of V shape, in cross section than the lugs of the first embodiment, but their contours in axial planes are substantiall the same.

The central axial section of the intervening edge portions 39 is substantially as shown in Figure 11. As in the first embodiment, there is line contact at each lug during application and point engagement with the locking ring when the cap is fully engaged; The sealing efliciency is the same as in the first embodiment, the main difference being that the lug formations of the second embodiment are less conspicuous and hence preferable in some situations.

While with three sets of twin lugs added security of seal is afforded as over three equi-distantly spaced single lugs, there is still maintained the desirable feature of the latter that the pryingoff at one of the lug formations results in the lifting up of more than half of the cap.

It will be understood that the invention is susceptible of other variations as to'form and arrangement of parts without departure from the scope of the following claims.

I claim:

1. A snap-on andpry-oflf cap including a top and a resilient substantially cylindrical skirt depending from said top and including a continuous curled bottom edge, said skirt being provided with three only of substantially equi-distan-tly spaced sets of two inwardly projecting lugs of which each lug of each set has an upper portion which inclines gradually outwardly and upwardly relative to the inner surface of the skirt above said edge and merges into said surface a distance above said edge and has a lower portion in said edge inclined gradually downwardly and outwardly relative to said inner surface, said lugs being each engageable with point contact under a container locking ring of substantially less maximum diameter than the maximum inside skirt diameter when the cap is applied, said lower and upper portions affording a shoehorn effect in the cap applying and removing operations respectively, each lug having an inward curve in the plane of said edge and the adjacent ends of the curves of the lugs of each set being immedi ately joined by an outwardly curved portion of said edge, and the distance between adjacent sets of lugs being at least twice the distance between the contact points of the lugs of each set.

2. A snap-on and pry-off cap including a top and a resilient substantially cylindrical skirt depending from said-top and including a continuous curled bottom edge, said skirt being provided with three only of substantially equi-distantly spaced sets of two inwardly projecting lugs of which each lu of each set has an upper portion which inclines graduall outwardly and upwardly relative to the inner surface of the skirt above said edge and merges into said surface a distance above said edge and has a lower portion maximum diameter than the maximum inside skirt diameter when the cap is applied, said lower and upper portions affording a shoehorn effect in, the cap applying and removing operations respectively, the distance between the contact points of the lugs of each set of lugs being about one-fourteenth or less of the inside circumference of the skirt.

3. The combination with a container having a portion defining a mouth terminating in a lip, said portion including a rigid'continuous external locking ring, of a snap-on and pry-ofi cap including a top and a resilient substantially cylindrical ski-rt depending from said top and having a continuous curled bottom edge, a gasket in said cap, said skirt being provided with three only of substantially equi-distantly spaced sets of two inwardly projecting lugs of which each lug of each set has an upper portion which inclines gradually outwardl and upwardly relative to the inner surface of the skirt above said edge and merges into said surface a distance above said edge and has a lower portion in said edge inclined gradually downwardly and outwardly relative to said inner surface, said lugs being engaged under said ring each with point contact and with a wedging effect so that a continuing axial tension is exerted on said skirt whereby to compress said gasket between the cap top and the container lip, the internal diameter of said skirt being substantially greater than the maximum diameter of said locking ring, said lower and upper portions affording a shoehorn effect in the cap applying and removing operations respectively, each lug having an inward curve in the plane of said edge and the adjacent ends of the curves of the lugs of each set being immediately joined by an outwardly curved portion of said edge, and the distance between adjacent sets of lugs being at least twice the distance between the contact points of the lugs of each set.

4. The combination with a container having a portion defining a mouth terminating in a lip, said portion including a rigid continuous external locking ring, of a snap-on and pry-off cap including a top and a resilient substantially cylindrical skirt depending from said top and having a continuous curled bottom edge, agasket in said cap, said skirt being provided with three only of substantially equi-distantly spaced sets of two inwardly projecting lugs of which each lug of each set has an upper portion which inclines gradually outwardly and upwardly relative to the inner surface of the skirt above said edge and merges into said surface a distance above said edge and has a lower portion in said edge inclined gradually downwardly and outwardly relative to said inner surface, said lugs being engaged under said ring each with point contact and with a wedging efiect so that a continuing axial tension is exerted on said skirt whereby to compress said gasket between the cap top and the container lip, the internal diameter of said skirt being substantially greater than the maximum diameter of said lockin said edge inclined gradually downwardly and outwardly relative to said inner surface, said lugs being each engageable with point contact under a container locking ring of substantially less ingring, said lower and upper portions affording a shoehorn effect in the cap applying and removing operations respectively, the distance between the contact points of the lugs of each set of lugs being about one-fourteenth or less of the inside circumference of the skirt.

LOUIS, L; LAUVE.

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