US2233105A - Metallic closure - Google Patents

Description

Feb. 25, 1941. R, McCOMBS METALLIC cnosums Filed June 50, 1934 I I I I I .0 I I I I I I i only by mutilation of the outer shell.

Patented Feb. 25, 1941 PATENT OFFICE METALLIC CLOSURE Arnold It. McCombs, Lancaster Township,

Lancaster County,

Pennsylvania Pa., assignor to Armstrong Cork Company, Lancaster,

Pa., a corporation of Application June 30, 1934, Serial No. 733,195

12 Claims.

My invention relates to metallic closures and more particularly to the so-called double shell closures commonly used in sealing bottles and jars. These double shell closures are generally formed of an inner cap, which is provided with means for removably securing the cap to a receptacle, and an outer shell telescoped over the inner cap and covering the skirt and at least a portion of the top thereof. The outer shell is usually smooth surfaced throughout for appearance and in order to permit decoration of the top and skirt. The shell may, however, be embossed or otherwise formed as desired. The cap and shell are formed of light-weight sheet metal, such as tin plate, which is readily drawn and shaped to the desired contour.

One of the major problems incident to the manufacture of a closure of this type is to prevent relative rotation of the cap with respect to the outer shell. The closures are usually so constructed that they are inseparable without mutilation and upon sticking of the component engaging means, such as screw threads, caused by the application of the closure to the receptacle with great turning effort or by reason of adhesion, the turning effort required to overcome such friction or adhesion is greater than that required to cause the locking means to fail, whereupon, the outer shell rotates while the cap remains immovable. The cap is then removable As an example, a'28 millimeter screw closure having well formed threads and applied to a properly finished glass container in the usual manner will require an average of 13.4 pound inches turning effort for removal, whereas, the same closure when applied tightly or adhesively secured by reason of corrosion or seepage of the contents of the receptacle, may require as much as 30 pound inches turning effort for removal. It will be apparent, therefore, that the interlocking of the cap and shell must be such that relative rotav tion of the parts will not occur by-reason of the excess stress required to remove a tight fitting closure.

Various types of locking constructions have been suggested, many of which are commercially impracticable and others, while they can be produced and are effective for preventing such relative rotation, require intricate machinery for manufacture and assembly and are relatively expensive to produce.

It is an object of my invention to provide an improved type of closure in which relative rotation of the inner cap with respect to the outer My invention contemplates a. closure in which 10 thereceptacle engaging portion is held in fixed position with respect to the outer shell by means of a flange provided on the skirt of the inner portion terminating in a cut surface, which when urged into engagement with the skirt of the 15 outer shell, causes frictional or cutting engagement, preventing relative rotation of the parts. In the preferred embodiment, an outwardly and downwardly extending flange is provided on the skirt of the inner cap, which flange is urged upwardly and outwardly into firm engagement with the skirt of the outer shell. Stated in other words, the outwardly and downwardly extending flange is capable of being flexed whereby the diameter thereof may be decreased to permit ready assembly of the cap and shell and increased to cause locking engagement of the component parts.

The method consists in urging an outwardly extending flange terminating in a cut surface into engagement with the inner surface of the skirt of an outer shell telescoped over. an inner cap, upon the skirt of which said flange is formed, by changing the diameter of at least one of the parts whereby the cut surface firmly engages the skirt of the outer shell and prevents relative rotation between the cap and shell. The method further contemplates urging an outwardly and downwardly extending flange upwardly and outwardly into engagement with the inner surface of 4 the skirt of the outer shell.

In order that my invention may be more clearly .understood, I will describe the same in connec- Qtion with the attached drawing in which-- Figure 1 is an exploded view partly in elevation and partly in section showing an outer shell and an inner cap prior to assembly;

Figure 2 is a view partly in elevation and partly in section showing the preferred embodiment of my new closure;

Figure 3 is a view partly in elevation and partly in section showing a modified construction;

Figure 4 is an enlarged section taken on the line IV-IV of Figure 3;

Figure 5 is a diagrammatic view illustrating the relative position of the flange with respect to the outer shell; and

Figures 6, '7, 8 and 9 are broken sectional views showing modified embodiments of my invention.

Referring first to Figure 1, an outer shell 2 is formed from a blank of sheet metal, such for example as 32 gauge tin plate which may be first suitably decorated as by lithographing. This shell is provided with a top portion 3 and a depending skirt portion 4 which is formed by a single, simple drawing operation familiar to those skilled in the art.

An inner cap, generally indicated by the numeral 5, is formed from a blank of tin plate in two operations; a shell similar to the shell 2, but having the exposed edges of the skirt formed into a flange, being first drawn and this shell thereafter passing into engagement with a screw threading and knurling die whereby a thread 6 and a knurled portion 1 are formed on the skirt. As shown in the drawing, the top 8 may be flat, or if desired, may be contoured to provide a liner forcing annulus and have a dome shaped top as shown in Figure 6. In the event the top 8 be domed, as shown in Figure 6, it is desirable to have the top 3 of the outer shell also domed, with the radius of curvature of both the same, so that the outer shell will not be deformed upon subsequent assembly of the two parts. Screw threads have been illustrated as providing means for removably securing the closure to a receptacle. Other types of engaging means may be substituted for these screw thread formations.

According to my preferred embodiment, a flange 9 is provided upon the exposed edge of the skirt of the inner shell terminating in a cut surface. As pointed out above, this flange may be formed during the original drawing operation and if so formed it will have a tendency to be irregularly shaped, or, in other words, will vary in length from the line of intersection with the skirt to the edge thereof. It is desirable to trim this flange to a uniform and desired size and this may be conveniently done by means of a horizontal punch type cutting machine.

In Figure 1, the flange extends at an angle of about 105 with respect to the skirt of the cap. This angle permits ready assembly and subsequent deformation. The particular angle to be employed is not critical although the flange should, in order to provide the preferred biasing action, extend outwardly and downwardly. As is better illustrated in Figure 5, the flange length from the line of intersection It) with the skirt to the exposed edge ll of the flange 9 is greater than the distance from any point on the line ID to a corresponding point I2 on the inner surface of the skirt of the outer shell lying in a plane normal to the axis of the cap, or stated in other words, an arc swung from any point on the line of intersection l0 having a radius equivalent to the skirt length will intersect the inner surface of the skirt of the outer shell. This is desirable in order that upon upward movement of the flange 9 about the line of intersection III, the flange will firmly engage the surface l3 before reaching a position normal to the axis of the cap. The difference in length between the flange 9 and the line Ill-42 will depend to some extent upon the deformability of the outer shell.

To insure that the can be properly positioned with respect to the outer shell, I prefer to have the flange formed with an outer diameter slightly greater than the inner diameter of the shell. The flange is sufliciently flexible to permit telescoping of the two parts and the inner cap having a flange about .002" greater in diameter than the inner diameter of the outer shell is readilyassembled by means of an inserting plunger. The cap and shell may be forced into position with the head portions 3 and 8 in engagement, or, if desired, a cardboard or other cushioning disk D may be inserted therebetween as shown in Figure 7.

After telescoping, the cut surface of the flange is urged into firm engagement with the inner surface of the skirt of the shell. This may be accomplished by decreasing the inner diameter of the skirt of the shell or by increasing the diameter of the flange on the cap, or both. The diameter of the skirt may be reduced by curling the exposed edge thereof under the flange whereby the skirt will curl inwardly from the line of contact with the flange, whereby the frictional grip of the metal parts, enhanced by the action of the cut surface, will prevent rotation.

I prefer, however, to urge the flange 9 upwardly whereby the outer diameter thereof is increased and the cut surface flrmly engages the inner surface of the outer shell. Various means may be employed for urging the flange upwardly, such for example as a suitably shaped plunger having an outer diameter substantially the same as the inner diameter of the outer shell. The cut surface has a tendency to be somewhat roughened as is common in cut metallic surfaces of this type and this surface upon being forced upwardly against the metal of the outer shell forms microscopic grooves therein which greatly enhance the frictional grip. The flange which is normally biased downwardly and out of the position it now assumes should preferably be held in strained or upward position, which, as shown in Figure 2, lies at an angle slightly greater than with respect to the skirt of the cap. It is desirable, although not essential, that the entire cut surface ll of the flange engage the shell because of the increased frictional grip provided thereby. There may be a slight deformation of the outer shell by reason of the pressure applied by the flange if 32 gauge tin plate is used, but this will not be noticeable. The flange may be held in proper position by any simple deformation of the skirt of the outer shell below the line of contact with the flange. A plurality of indentations may be employed or the exposed edge of the skirt may be turned under the flange thereby holding it in strained position. Any angularly extending por- (tion provided on the outer shell which holds the flange in such position without materially weakening the frictional grip will be satisfactory.

If desired, the skirt of the outer shell may be deformed prior to insertion of the cap and the flange then urged into its strained position snapping under the deformed portion of the shell. According to -my preferred embodiment, however, the flange is urged upwardly and the outer shell deformed by a single operation. As shown in Figure 2, this is accomplished by forming an inwardly, upwardly and outwardly extending bead l5 into engagement with the flange 9 whereby the flange is urged into firm engagement with the shell and held in that position by the bead. A simple crimping or curling tool of the type now employed in the metallic closure art may be used for this purpose. The bead may be turned so that the cut edge thereof engages the inner surface of the shell. It is desirable that no out surfaces be exposed which might have a tendency to become corroded upon contact with the contents of the bottle. A somewhat enhanced gripping action will be obtained,

however, if the cut surfaceof the exposed edgeis illustrated in which the flange l6 has formedv on the exposed edge thereof a plurality of serrations or tooth-like elements l'l. These may be formed during the flange trimming operation by the use of a suitably shaped cutting die. I have found that if the portion between the cuts is about four times the width of the cut a desirable gripping action is obtained. This is probably due to the fact that, upon being urged upwardly, the tooth-like elements I1 have a tendency to scrape the metal, leaving the metal uncut in the portions l8 between the teeth. In other words, the skirt of the outer shell is provided with shallow indentations corresponding to the teeth I! and raised portions l8 therebetween. This forms a highly desirable interlocking engagement of the parts which is enhanced by reason of the fact that the teeth I! engage the surface of the skirt and also aid in preventing relative rotation. The formation or shape of the serrated edge is not controlling, although I have found that when serrations terminating in sharp points have been employed they have a tendency to become distorted upon the application of pressure and are not as effective as relatively flat surfaces with narrower slots cut therebetween.

While it is desirable that the flange terminate in a cut surface, it will be understood that the flange may be provided with a bead or turned in portion B as shown in Figure 8 which will present a smooth surface for engagement with the outer shell. This will eliminate the trimming operation referred to above but will necessitate another forming operation.

As is common in this art, the outer covering has been called a shell and the inner portion a cap. It. will be understood that the shell need not cover the entire top portion, but if it be as shown in the drawing, Figuresl to 5, the cap may be in the form of an annulus A as shown in Figure 9 having a shoulder S rather than a complete top with engaging means and a deformable flange. The preferred construction, however, is the form illustrated, wherein both shell and cap are provided with a complete top and skirt.

While I have described and illustrated the preferred embodiment of my invention, it will be understood that the invention is not so limited but may be otherwise embodied within the scope of the following claims.

I claim:

1. A double shell closure comprising an inner metallic cap and an outer metallic shell, an outwardly and downwardly directed expansible flange on the skirt of the cap engaging the inner surface of the shell and biased downwardly, and an angularly extending portion on the skirt of the shell engaged with the lower face of said flange and holding said flange in strained position against the tendency to return to its normal position.

2. A double shell closure comprising an inner metali'c cap and an outer metallic shell, an outwardly and downwardly directed expansible flange on the skirt of the cap engaging the inner surface of the shell and biased downwardly, and a bead formed on the exposed edge of the skirt of said shell holding said flange in firm engagement with said shell and in strained position.

3. A double shell closure comprising an inner metallic cap and an outer metallic shell, an outwardly and downwardly directed expansible flange on the skirt of the cap lying at anangle greater than 90 with respect to the skirt of said cap and terminating in a cut surface lying in flrm engagement with and penetrating the material of the skirt of said shell, and an angularly extending portion on the skirt of said shell engaged with the lower face of said flange and holding said flange in fixed position.

4. A double shell closure comprising an inner metallic cap and an outer metallic shell, an outwardly and downwardly directed expansible flange on the skirt of the cap having a serrated surface lying in firm engagement with the skirt of the outer shell, said flange being biased downwardly and an angularly extending portion on the skirt of the shell below the line of contact of said flange holding said flange in strained position.

5. Adouble shell closure comprising an inner metallic cap and an outer metallic shell, a flange on the skirt of the cap having a serrated surface in which the tooth-like elements are at least four times the width of the cut portions, said tooth-like elements engaging the inner surface of the skirt of the outer shell, raised portions on the skirt of the outer shell intermediate the tooth-like elements and a bead on the skirt of the outer shell in firm engagement with said flange. i

6. A double shell closure comprising an inner metallic cap and an outer metallic shell, a flange on the skirt of the cap biased downwardlyand terminating in a cut, serrated surface, the serrated surface of the flange engaging the skirt of the outer shell, with raised portions intermediate adjacent serrations, and an angularly extending portion on the skirt of the outer shell below the line of contact of the flange holding said flange in strained position.

7. A double shell closure comprising an inner cap having a top and a skirt, an outwardly directed expansible flange formed on said skirt biased downwardly, an outer shell telescoped over the cap, a bead formed on the exposed edge of the skirt of said shell terminating in a cut surface firmly engaging said flange and holding the same in strained position.

8. A double shell closure comprising an inner cap having a top and a depending skirt provided with means for removably securing said closure to a receptacle, an outwardly and downwardly directed expansible flange formed on said skirt biased downwardly, said flange normally extending at an angle substantially greater than 90 with respect to the skirt, an outer shell hav ing a top and a depending skirt, a bead formed on the end of said skirt engaging the flange on the skirt of said cap and urging the same into firm engagement with the skirt of the outer shell at an angle of substantially 90 with respect to the skirt or said cap and holding the same in strained position.

'9. A double shell closure comprising a screw threaded cap telescoped within an outer shell,

an expansible flange on the skirt of the inner cap normally lying in a frusto-conical surface, a bead formed on the exposed edge of the skirt of the outer shell engaging said flange and holding the same in firm engagement with and penetrating the material of the skirt of the outer shell and in a geometric surface substantially appreaching a plane normal to the axis of the cap against the tendency to lie in a frusto-conical surface.

10. A double shell closure comprising an inner metallic cap and an outer metallic shell, an out wardly directed and downwardly biased expansible flange on the skirt of the cap terminating in a cut surface lying in firm engagement with the skirt of the outer shell and a bead on the skirt of the outer shell terminating in a cut surface lying in firm engagement with said flange and holding the same in strained position.

11. A screw cap embodying therein a skirted outer shell, and an inner shell inclosed thereby having a skirt provided with means adapted to engage complementary means upon a container,

upon a container, and an outwardly and downwardly directed flange about the bottom thereof having a plurality of deformed edge tangs, said tangs penetrating the material of the skirt of the outer shell, and the inwardly turned edge of the skirt of the outer shell frictionally engaging said flange intermediate said tangs and the skirt of the inner shell, and said tangs being clamped between said turned portion and the skirt of the outer shell.

ARNOLD R. MCCOMBS.

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