US1842429A - Screw cap - Google Patents

Description

- E, SCOFIELD Jan. 26, 1932.

' SCREW CAP Fil ed July 28 1927 INVENTQR Edyar S00 z'eld a on Patented Jan. 26, 1932 UNITED STATES PATENT OFFICE EDGAR SCOFIELD, OF NEW YORK, N. Y., ASSIGNOR TO ANCHOR CAP CLOSURE CORPORA- TION, 0]! LONG- ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK SCREW CA1 Application filed July 28,

The present invention relates to closure caps and more particularly to a screw cap adapted to form an effective hermetic seal on a suitable container.

Various attemptshave been made to obtain effective hermetic seals with short skirt screw caps. One has been to use wax liners, that is, wax' discs co-extensive with and mounted below the cover portion of the cap. Another has been permanently to fix a flat gasket to the cover portion of the cap directly above the mouth of the container, the gasket being secured to the cover portion by a suitable adhesive. These and other attempted expedients are not only expensive but tests actually show that they are ineffective for hermetic seals.

Applicant has discovered that one of the I reasons for the inability of the present screw caps to form an effective seal is due to the use of short skirts to effect the necessary saving in material to meet commercial competition. Because of these there is not suflicient space between the knurled portion and the beaded edge to permit a thread to extend completely around the skirt. The cap is therefore re tained in position by an engagement extending only about three-quarters of the way around the circumference of'the cap. This unequal pull on one side of the cap actually raises the portion notretained in downward position and renders the seal ineffective. Further, the seals formed being edgeseals, any slight irregularity in the skirt of the cap or in the position of the threads on the receptacle completely disrupt theseal irrespective of other factors. Then too, imperfec tions are more likely to occur at the mouth.

of the container than elsewhere and an edge seal is therefore more susceptible to irregularities.

The present invention overcomes these difficulties by changing the pitch of the thread on the ,cap and container so that it extends at least completely around the cap and preferably suificiently far around so that the ends have a generous lap. In this way a positive downward pull exists throughout the circumference of the cap when it is screwed home. An effective and uniform seal is ac- 1927. Serial in; 208,965.

cordingly formed. To take care of any irregularity in the cap or container, a combined edge and side seal is provided by bevelling the outer periphery of the container and by providing a substantially rectangular gasket at the junction of the skirt and cover portion of. the cap. In this way one edge of the gasket engages the bevelled edge of the container and the gasket is compressed diagonally. With such a seal slight variations in the locations of the thread are not material. The substantial increase in the vertical movement of the cap during sealing, facilitates the sealing operation and minimized the efi'ects of irregularities.

An object of the present invention is to provide a short skirt screw cap adapted to form an effective seal throughout the circumference thereof.

Another object of the invention is to provide a closure cap adapted to engage a container firmly throughout the periphery thereof and to compress uniformly a gasket about the mouth of the container.

A still further object of the invention is to formwith a screw cap a combined side and edge seal by bevelling the outer peripheryof the side wall of the container adjacent the mouth thereof and forming the seal on said bevelled portion.

Other and further objects of the invention will be obvious upon an understanding of the illustrated embodiment about to be described and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, wherein Fig. 1 is a side elevational view of a sealed package in accordance with the present invention;

Fig. 2 is a fragmentary sectional view illustrating the shape and position of the gasket prior to the sealing operation;

Fig. 3 is a fragmentary sectional view showing the closure cap in sealed position;

Fig; 4 is a sectional view of another form prior to the sealing operation;

cap is knurled as shown at 7 to facilitate apouter periphery ofthe gasket against the mg the gasket in position .tion to a container.

plication and removal thereof, and to improve the appearance of the cap.

Intermediate the knurled portion 7 and the beaded edge 6 is a continuous thread 8. This thread preferably extends completely around the skirt of the cap with. a generous lap'at the ends of the thread as shown at 9 in Fig. 1. It is generally'necessary, with the types of caps now manufactured for screw containers, to reduce the pitch of. the thread materially in order to obtain the lap at the ends'of the thread without increasing the length of the skirt. This thread on the cap co-operates with the corresponding thread 2 on the container and engages the container; completely around the mouth thereof in all instances. The downward pull on the cap is therefore uniformly distributed and there is no tendency, due to unbalanced pressure, for one side of the cap to rise.

A sealing gasket 10, preferably of rectangular cross-section, is provided at the junction of the skirt and cover portion of the cap. The circumferential dimension of the gasket isslightly larger than the internal circumference of the skirt of the cap so that when mounted therein the tendency of the gasket to expand will hold it in proper position with the upper side of the gasket against the-cover portion of the cap and the skirt of the cap. The threads 8 on the cap form projections which also assist in retainprior to its applica- The outer periphery of the container is bevelled as shown at 11.to form an inclined sealing zone in position to be engaged by the gasket. The-shape of. the sealing zone may be varied buta substantially straight bevel at an angle of forty-five to sixty degrees has been found to give excellent results. The inner edge of the gasket engages the bevel and asthe cap is screwed further the edge of the gasket is pressed diagonally The pressure between the gasket and container is greatest at the edge. of the gasket which is substantially at the center of the seal, the pressnredecreasing toward the outer edges of the seal.

In this manner a-maximum pressure can be obtained at the sealing zone with a minimum rotative eflort; The inclined sealing zone mouth of the case the edge of the container engages the gasket pressing it into an angular form with part ofthe gasket forming a seal between the mouth of the container and the cap and with the other part of the gasket forming a seal between the cap and the-side wall of the container. A combined side and edge seal is formed with the edge of the container pressed deeply into the gasket. The shape of the gasket is-chan'ged and a wide seal is attaine p The caps and gaskets are preferably manufactured, assembled, and shipped in assembled state to packers. This is possible due to the fact that the gaskets resist effectively the jars incident to trans ortation and remain in proper position. Thus the sealing operations are facilitated because the packers do not have to bother with the gaskets and the manufacturers of, caps, due to the large quantities handled, can utilize automaticmachines for assembling the caps and gasket-s and thereby dispense with hand assemblage which would be necessary with small packers. a It will be seen that a very effective hermetic seal has been provided at a minimum cost with a short skirt continuous thread screw cap. The caps and gaskets may be shipped in assembled state and applied to containers rapidly. Defective seals due to irregularities in containers are-reduced to a minlmum- Further, the packages are fully capable of withstanding the rough usage to which they may be sub ected in transportation. The cap may be used repeatedly for sealing and resealing thereby maintaming the contents of the package properly sealed during consumption thereof.

As various changes may b'emade in the above embodiment without departing from the spirit of the invention, it is to be understood that all matter herein is to be inter- Having thus described my invention, I

' claim:

1. A sealed package comprising a container having an ,annular bevelled surface adjacent the mouth thereof, the lower edge of said bevelled surface-havinga diameterequal to the-exterial diameter of the container, a screw closure cap having a'cover portion and a depending skirt adapted to engage said container, and a gasket at the juncture of said skirt and said cover portion held under compression by the bevelled portion of said container.

to be attached to. said container, and a sub stantially rectangular gasket at the juncture of said skirt and cover portion, one edge of said gasket being pressed against said bevelled portion, whereby said edge is forced diagonally inward'to such a'n extent that a wideeifective seal is formed.

3. A sealed ,package comprising a threaded container having an annular bevelled sur-- face adjacent themouth thereof, a screw closure cap having a cover portion and a depending skirt, and a substantially rectangular gasket at the juncture of said skirt and said cover portion, one edge of said gasket being forced inwardly by the bevelled edge of said container to form an efiective seal between said closure and said container.

4. A sealed package comprising a threaded container, a closure cap having a cover portion and a depending skirt with a continuous thread extending completely around the skirt, a substantially rectangular gasket having a side resting against the cover portion and another side resting against the skirt of said cap to envelop one corner thereof therebetween and to provide a converging pressure on the gasket to forcethe diagonal corner of the gasket against the rim of the container to form an effective seal.

5. In a sealed package, the combination of a container having an annular mouth portion and a closure cap comprising a cover portion and a depending skirt of relatively short length, the upper part of said skirt being knurled or corrugated, the lower part having a'beaded edge and the intermediate part having a continuous thread of such pitch that the thread extends completely around the skirt of the" cap and overlaps slightly whereby when applied to a container the thread thereon engages the container effectively throughout its circumference and an annular gasket disposed in the upper part of said skirt, having a minimum diameter greater than the inner edge of the mouth of the container but smaller than the outer edge of said container, whereby said gasket is adapted to be diagonally compressed against the outer, edge of the container to form an effective seal.

6. A sealed package comprising a containing its upper side resting against the cover portion and its outer peripheral side resting against the skirt of the cap, the corner of the gasket diagonally disposed with respect to the corner of the gasket at the junction of the skirt and cover portion of the cap engaging the upper rim of the container and forming a seal therewith.

A sealed package comprising a screw closure cap having a cover portion and a depending skirt, a substantially rectangular gasket at the junction of said skirt and said cover portion, and a container having projections thereon adapted to engage said closure cap, the outer corner of the rim of the container being rounded, the lower inner corner of the rectangular asket engaging said outer rounded corner tainer to form an effective seal therewith.

8. A sealed package comprising a container, a screw closure cap having a cover portion and a depending skirt, and a gasket substantially square in cross-section mounted in said cap at the junction of the skirt and cover portion thereof, the lower inner'peripheral edge of said gasket engaging the rim of the container to form atight seal therewith by means of pressure exerted substantially in a diagonal direction with respectto the gasket.

9. A sealed package comprising a container having an annular bevelled surface adjacent the mouth thereof, said bevelled surface merging into the sidewall of the container, means on the container below said bevelled surface for engaging a screw closure cap, a sheet metal screw closure cap having a cover portion and a depending skirt, said skirt having inwardly extending portions adapted to engage said means on the container, and a rubber gasket at the junction of said skirt and said cover portion held under compression by the bevelled portion of said container.

EDGAR SCOFIELD.

er, a screw closure cap secured thereto having a cover portion and a depending skirt,

and a substantially rectangular gasket havthe rim of the con-

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