Tear-off Closure With Reinforcing Rib

Abstract

A tear-off closure is provided which has a top end wall and a depending skirt and having a tear strip defined by scoring divisive of the end wall and into the skirt, the tear strip having at least one embossed rib therein which extends from a location toward the center of the closure radially outward to a location adjacent the shoulder of the closure between its end wall and the skirt to ensure severance of the tear strip over such shoulder of the closure. The closure may further have a raised rim around a recessed central panel in its top end wall, with the rib in the tear strip extending from the recessed central panel into the rim of the closure.

Description

BACKGROUND OF THE INVENTION

It is known to provide a tear-off closure which has a tear strip across its end wall and into its skirt, and a pull tab attached to the tear strip as is shown in LaBarge et al. U.S. Pat. No. 3,441,163 and Schay U.S. Pat. No. 3,353,739. Such closures frequently include means such as a recessed panel in the end wall and a rim around the recessed panel to protect the tab from accidental opening. With this closure structure, there has been some difficulty in ensuring that severance of the tear strip will follow the score line over the rim of the closure between its end wall and skirt. The rim of the closure produces a resistance to rupture of the score line which may result in premature severance of the tear strip from the closure. An attempt was made to correct this problem by providing an upwardly embossed island in the tear strip adjacent to, but not extending into, the rim of the closure to form a lever in the tear strip. Although this embossed island improved the opening characteristics of the closure, the closure was not completely foolproof. In some cases, the tear strip would be severed from the closure at the top of the rim and not through the skirt of the closure as is desired. Accordingly, a tear-off closure is desired which has a tear strip across its top and into its skirt and which will open properly to form a split closure member regardless of the nature and direction of the force which is exerted upon the tab.

SUMMARY OF THE INVENTION

This invention provides a tear-off closure which has a tear strip across its end wall and into its skirt, and which has at least one embossed rib in the tear strip starting in a center portion of the closure and extending outwardly to a location adjacent the shoulder of the closure between its end wall and skirt to aid in severing the tear strip over the corner of the closure and form a partially split closure member which can be lifted from the container.

Accordingly, an object of the invention is to provide an improved tear-off closure which eliminates the problem of premature separation of the tear strip from the closure.

Another object of the invention is to provide a closure which has at least one embossed rib in its tear strip to aid in severing the tear strip over the corner of the closure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the invention will be further understood and appreciated with reference to the following description and drawings attached thereto wherein;

FIG. 1 is a top plan view of a closure of the invention on a container;

FIG. 2 is a partial elevation view of the closure and container of FIG. 1;

FIG. 3 is a partial cross-sectional view of the closure and container of FIG. 1 taken along line III--III;

FIG. 4 is a partial cross-sectional view of the rib in the closure of FIG. 1 taken along line IV--IV;

FIG. 5 is a partial perspective view of the closure-container combination showing partial opening of the closure;

FIG. 6 is a partial cross-sectional view similar to FIG. 5 showing further severance of the tear strip;

FIG. 7 is a top plan view of an alternative form of closure of the invention;

FIG. 8 is a partial cross-sectional view of the closure and container of FIG. 7 taken along line VIII--VIII;

FIG. 9 is a partial cross-sectional view of a rib in FIG. 7 taken along line IX--IX; and

FIG. 10 is a partial vertical cross-sectional view of the closure-container of FIGS. 7 and 8 showing severance of the tear strip.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the several illustrations appended hereto, metal closures or closure fitments are shown in the form of permanently deformable drawn metallic shells each of which has a top portion and a depending skirt terminating in a circumferential bead, and having a tear strip with a lever type pull tab affixed thereto divisive of the closure fitment to facilitate removal of the fitment. A cup-shaped liner of a resilient plastic material may be provided within such a fitment to form a closure assembly. A container with entrance mouth is illustrated as a conventional open top jar, bottle, or the like, made of glass, plastic or like material, and suited to have such a closure assembly affixed thereto.

Referring to the illustrations, FIGS. 1, 2 and 3 show a closure fitment 10 formed from sheet metal or other permanently deformable material, and preferably from a thin sheet of aluminum or an alloy thereof, which is adapted to be secured over the entrance mouth of a container 12. Closure fitment 10 is comprised of a top end wall 14 and a depending skirt 16 terminating in a circumferential bead 18. The closure fitment 10 is weakened or scored along line 20 to form or define a tear strip 22 divisive of the closure top from a starting location adjacent or towards the periphery of the top relative to its center, to a generally opposite location, and from there divisive of the closure fitment along one side of the tear strip 22 all the way to the edge of the sheet material of the fitment, and along the other side of the tear strip 22 to a location short of the edge of the sheet material leaving a bridge or ligament of unscored metal between its end and the bottom of the skirt 16. The closure fitment 10 may also be scored outwardly of and adjacent to the starting end of the tearing strip 22 by means of two scores 24. Scores 24 intersect the primary score 20 on opposite sides of the apex of the tear strip 22, and extend from the primary score outwardly to the shoulder or corner between the end wall 14 and the skirt 16 of the closure. Alternatively, a single score could be provided which intersects the primary score 20 at or near the apex of the tear strip and which extends outwardly to the skirt of the closure. Fitment 10 may further include a downwardly embossed circular depression 26 in which a tab 30 may be seated and a number of upwardly embossed arcuate ribs 28 on end wall 14 around its periphery to facilitate stacking containers on top of one another, and to protect the tab from accidental opening of the closure.

Pull tab 30, illustrative of the type of tab that may be employed, is attached to the tear strip 22 in its starting end by means of an integral rivet 32. Pull tab 30 is a reverse acting, double-lever type having a centrally open ring body 34 with a tongue 36 for affixation of the rivet 32. The tongue 36 is bendable at its junction with the tab body 34 so that the tab can be easily initially lifted from the surface of the fitment top for severance of the tear strip 22. As affixed to the tear strip, the tab 30 lies substantially flush with the surface of the bottom wall of depression 26, and ribs 28 protect the opening structure from accidental opening or rupture of the score lines.

A liner 38 may be provided within the fitment 10 for effecting a seal when the assembly is affixed to a container 12, and may serve as a reclosure for the container after opening. Liner 38 may be formed from any of a variety of materials such as rubber, paper, cardboard, or a synthetic plastic such as polyethylene, polypropylene or polyvinyl chloride. Liner 38 has a complete spanning top portion including a recessed central panel 40 and a raised rim 42 with a skirt 44 depending therefrom, and is dimensioned to fit or nest in closure fitment 10. An upwardly open groove 45 may be provided on the closure skirt for engagement of fitment bead 18 so that an assembly of the fitment and liner will not separate during handling prior to affixation to a container.

The container mouth entrance illustrated in FIGS. 3 and 6 is representative of a structure suitable for affixation of a closure fitment 10 and liner 38. It will be observed that container 12 provides an entrance mouth defined by an outwardly projecting closure securing bead 46 having an upwardly facing sealing surface, a laterally facing side sealing surface and a shoulder having an undersurface blending into the container wall therebelow.

In the embodiment illustrated in FIGS. 1-6, tear strip 22 has an upwardly embossed rib 48 centrally located therein which extends from centrally in an essentially flat top end wall 14 outwardly to a location adjacent the corner of the fitment between its end wall and skirt to structurally strength the tear strip during opening. As shown in FIG. 4, rib 48 has a generally arcuate transverse cross section, and extends outwardly at least to, and preferably beyond, a chordal line X--X drawn through the intersections of score line 20 with the corner of the closure between the end wall 14 and the closure skirt 16 (FIG. 1). Rib 48 in combination with the curved arc of the closure skirt between the two legs of score 20 reinforces tear strip 22 to substantially eliminate bending of the tear strip between the end wall and skirt of the closure during opening. Bead 18 around the bottom edge of the closure skirt also helps to reinforce tear strip 22 and prevent bending of the tear strip during opening. By eliminating bending of the tear strip during opening, rib 48 greatly facilitates severance of the tear strip over the corner of the closure.

In prior art closures which had tear strips which were not reinforced against bending at the corner between the top end wall and skirt of the closures, the tear strips would sometimes bend at the corner of the closure during opening and this would subject the metal in the tear strip in the immediate area of severe bending to much higher than average bending stresses. Such excessively high localized bending tend to weaken the metal along the line of bending in the tear strip, so that when they are superimposed on top of the normal tensional stresses induced in the tear strip during opening the path of tearing may be directed inwardly of the score into the tear strip to cause premature severance of the tear strip. However, with rib 48 extending at least to chordal line X--X in a closure of the invention, bending of the tear strip 22 at the corner of the closure is substantially avoided and the creation of excessively high localized bending stresses in the tear strip is substantially avoided. Tear strip 22 may flex slightly during opening, but the central portion of tear strip remains substantially rigid against bending. By avoiding bending and excessively high localized bending stresses in tear strip 22, premature severance of the tear strip is avoided. Metal fitment 10 is ruptured along score 20 as it desired rather than rupture the unscored metal in the tear strip between the score lines. Accordingly, severance of tear strip 22 will convert closure fitment 10 into a partially split member which can be easily removed from a container as will be described.

To open a container having a closure of the invention affixed thereto, the free end of the pull tab 30 is lifted to fulcrum the tab about a point outwardly of score line 20, causing tongue 36 on the tab to bend or flex at its juncture with the tab body and exert an upward force on rivet 32 and tear strip 22. This causes initial rupture of score 20 around the attachment rivet at the starting end of the tear strip. After initial rupture of score 20 around the starting end of tear strip 22, continued pulling of tab 30 ruptures the score along both sides of the tear strip into the closure skirt 16. During such rupture, rib 48 reinforces the portion of the tear strip in which it is located and maintains the tear strip as a substantially rigid member as shown in FIG. 6, although it may flex slightly between the top end wall 14 and skirt 16 of the closure. Initially, rib 48 may fulcrum or pivot about its outer end adjacent the corner of the closure as permitted by the resilience and slight flexing of the tear strip at such corner. However, the tear strip is quickly flexed to its maximum as limited by rib 48 and by the curved skirt portion in the tear strip, and the point of fulcruming moves to bead 18 on the bottom edge of the tear strip as illustrated in FIG. 6 to rupture score 20 down the closure skirt. During such fulcruming of the rigid portion of tear strip 22, score 20 along both sides of the tear strip is subjected to an almost optimum combination of shear and tension which ensures that the tear strip is not prematurely severed from the closure at the corner between its top end wall 14 and skirt 16.

As tab 30 is pulled, tearing stops at the end of the short leg of scoring in the skirt of the closure, but continues along the length of the other leg of scoring which preferably extends all the way to the edge of the skirt through bead 18 to convert the closure into a still unitary, partially split member with the tear strip attached to the skirt of the closure fitment by a ligament or bridge of metal between the end of the short leg of scoring and the bottom of the skirt. This results in confronting ends of the severed sectors of the closure fitment. Spreading such confronting ends will rupture at least one of the scores 24 adjacent the starting end of the tear strip and cause hinge-like opening of the closure without dismemberment thereof. The closure can then be lifted from the container leaving liner 38 which can be removed with ones fingers.

Referring to FIGS. 7, 8, 9 and 10, an alternative embodiment of the invention is illustrated in the form of a sheet metal closure fitment 50 which is adapted to be secured over the entrance mouth of a container 52. Closure fitment 50 is comprised of a spanning top portion or end wall with a recessed central panel 54, a raised rim 56 around the central panel, and a depending skirt 58 terminating in a circumferential bead 60. Central panel 54 includes an incline 62 at its periphery which connects central panel 54 and rim 56. Closure fitment 50 is weakened or scored along line 64 to define a tear strip 66 divisive of the closure top from a starting location adjacent or towards the periphery of the top relative to its center, to a generally opposite location, and from there divisive of the closure fitment along one side of the tear strip 66 all the way to the edge of the sheet material of the fitment, and along the other side of the tear strip to a location short of the edge of the sheet material leaving a bridge or ligament of unscored metal between its end and the bottom of the skirt 58. The closure fitment 50 may also be scored outwardly of and adjacent to the starting end of the tear strip 66 by means of two scores 68 which intersect the primary score 64 on opposite sides of the apex of the tear strip, and extend from the primary score outwardly to the shoulder between the rim 56 and the skirt 58 of the closure.

A pull tab 70 similar to the one that was shown on the closure illustrated in FIGS. 1-6 is attached to the tear strip 66 in its starting end by means of an integral rivet 72. Pull tab 70 is a reverse acting, double-lever type having a centrally open ring body 74 with a bendable tongue 76 for affixation of the rivet 72. As affixed to the tear strip, the tab 70 lies substantially flush with the surface of the recessed panel 54, and closure rim 56 protects the tab 76 and score 64 from accidental rupture.

A liner 78 may also be provided within fitment 50 for effecting a seal when the assembly is affixed to a container 52, and may also serve as a reclosure for the container after opening. It has a complete spanning top portion including a recessed central panel 80 and a raised rim 82 with a skirt 84 depending therefrom, and is dimensioned to fit or nest in closure fitment 50. The bottom of the liner skirt 84 may include an upwardly open groove 85 for engagement of container bead 60 so that an assembly of the fitment and liner will not separate prior to application to a container.

The container mouth entrance illustrated in FIG. 8 is similar to that illustrated in FIG. 3, and is defined by an outwardly projecting closure securing bead 86 having an upwardly facing sealing surface, a laterally facing side sealing surface, and a shoulder having an undersurface blending into the container wall therebelow.

In the embodiment shown in FIGS. 7-10, tear strip 66 has three upwardly embossed ribs in it which extend from central panel 54 into raised rim 56 around the central panel to structurally strengthen the tear strip during opening. The three ribs comprise a center rib 88 extending from a central portion of the container end wall into the rim of container, and two short ribs 90, one of either side of the center rib 88, which also extend from the recessed central panel 54 into the rim of the closure. As shown, the two shorter ribs 90 may diverge from the center rib 88 toward the periphery of the closure to form a rigid triangular-shaped zone in the closure. Referring to FIGS. 8 and 9, ribs 88 and 90 are inclined upwardly from the recessed central panel 54 to the area of the rim 56 and have generally arcuate transverse cross sections as did the rib of FIG. 4.

All three ribs in the tear strip 66 preferably extend outwardly to, and preferably beyond, a chordal line X--X drawn through the intersections of score line 64 and the corner of the closure between rim 56 and skirt 58. By extending the ribs 88 and 90 at least to chordal line X--X, the ribs, in combination with the closure skirt, will reinforce the tear strip so that it can bend very little if any as it is severed over the rim of the closure. As a result, the creation of excessively high, localized bending stresses in the metal in tear strip 66 is substantially avoided. This ensures that the metal in the fitment is ruptured along score lines 64 as is desired rather than rupture the unscored metal in the tear strip. Bead 60 around the bottom edge of the closure skirt also helps to reinforce the tear strip and ensures that the tear strip is not completely severed from the closure.

To open a container having a closure of the invention affixed thereto, the free end of pull tab 70 is lifted to fulcrum the tab about a point outwardly of score line 64, causing tongue 76 on the tab to bend or flex at its juncture with the tab body, and exert an upward force on rivet 72 and tear strip 66. This causes initial rupture of score 64 around the attachment rivet at the starting end of the tear strip. After initial rupture of score 64, continued pulling of tab 70 ruptures score 64 along both sides of the tear strip into the closure skirt 58. During such rupture, ribs 88 and 90 reinforce the portion of the tear strip in which they are located and maintain the tear strip as a substantially rigid member as shown in FIG. 6. This places the score 64 along the sides of tear strip 26 in an almost optimum combination of shear and tension, and ensures that the tear strip is not prematurely severed from the closure at rim 56.

As tab 70 is pulled, tearing stops at the end of the short leg of scoring in the skirt of the closure, but continues along the length of the other leg of scoring which extends all the way to the edge of the skirt through bead 20 to convert the closure into a still unitary, partially split member with the tear strip attached to the skirt of the closure fitment by a ligament or bridge of metal between the end of the short leg of scoring and the bottom of the skirt. This unitary, partially split member can then be removed from the container as was described with respect to the closure illustrated in FIGS. 1-6.

It will be apparent to those versed in the art to which the invention is addressed that particular embodiments have been selected for purposes of specific illustration and description, but that numerous variations can be made in the structural details of the selected embodiments without departing from the invention.

Claims

What is claimed is:

1. In a sheet metal closure having a top end wall and a depending skirt with a tear strip divisive of the top end wall and extending into the skirt, and further having a tab attached to the starting end of the tear strip, the improvement comprising at least one embossed rib in the tear strip extending from a central portion of the end wall outwardly at least to a chordal line drawn across the top of the closure through the intersections of the sides of the tear strip with the corner of the closure between its end wall and skirt to form a rigid section in the tear strip to resist bending thereof between the end wall and skirt of the closure whereby severance of the tear strip over the corner of the closure is facilitated.

2. A closure as set forth in claim 1 in which said rib is upwardly embossed.

3. A closure as set forth in claim 1 which includes a curled bead on the bottom edge of the closure skirt.

4. A closure as set forth in claim 1 in which said tear strip is defined by a U-shaped score having one leg which extends to the bottom edge of the closure skirt and a second leg which terminates short of the bottom of the skirt.

5. A closure as set forth in claim 1 in which said top end wall is substantially flat and said rib is substantially equidistant between the sides of the tear strip.

6. A closure as set forth in claim 5 in which said top end wall includes a circular depression in which said tab is seated.

7. A closure as set forth in claim 1 in which said top end wall includes a recessed central panel with a raised rim therearound and the tear strip includes three upwardly embossed ribs extending from the recessed central panel into the rim of the closure.

8. A closure as set forth in claim 7 in which said ribs extend outwardly at least to a chordal line drawn across the top of the closure through the intersections of the sides of the tear strip with the corner of the closure between its rim and skirt.

9. A closure as set forth in claim 7 including a center rib which extends from a central portion of the closure into the rim and two shorter ribs, one on either side of said center rib and diverging from the center rib as they extend toward the periphery of the closure.