US3435977A - Self-opening closure for a container - Google Patents

Description

April 1,1969 l f bEJACKE'y *y 3,435,977"

SELF-OPENING CLOSURE FOR A CONTAINER Filed Feb. -16, 1968 .Sheet Z Df INVENTOR. RAYMOND E. JACKE HIS ATTORNEYS 43A. @5A FIG-9 i 2m United States Patent Oice 3,435,977 Patented Apr. 1, 1969 3,435,977 SELF-OPENING CLOSURE FOR A CONTAINER Raymond E. Jacke, Henrico County, Va., assignor t Reynolds Metals Company, Richmond, Va., a corporation of Delaware Filed Feb. 16, 1968, Ser. No. 706,126 Int. Cl. B65d 55/00, 17/20 U.S. Cl. 21S-46 26 Claims ABSTRACT OF THE DISCLOSURE Many types of closure caps have been proposed for both narrow and wide mouth bottles which can be removed without using a separate opening tool. Many integral devices also have been proposed for providing a dispensing opening in the end closure of a can, for example, to enable easy dispensing of the contents of such can. In general, most of these previous self-opening closure devices are made of metal which is comparatively thick and hence comparatively expensive; further. many of these previous closure devices require that separate parts, such as pull tabs, be fixed thereto o1' involve complicated and expensive manufacturing procedures.

Summary This invention provides an improved container closure comprised of a plurality of layers of material and including both metallic and non-metallic layers to provide optimum structural strength while reducing the amount of metal required in a particular closure to reduce the cost thereof. Further, this invention provides such a closure which is self-opening in that it does not require separate opening tools, or the like.

Other details, uses, and advantages of this invention will become apparent as the following description of the embodiments thereof presented in the accompanying drawings proceeds.

Brief description of the drawings The accompanying drawings show present preferred embodiments of this invention, in which FIGURE 1 is a fragmentary perspective view illustrating one exemplary embodiment of this invention in the form of a crown-type closure cap installed in position on an associated bottle;

FIGURE 2 is an enlarged fragmentary perspective view particularly illustrating the arrangement of weakening lines provided in various layers of the closure cap of FIG- URE 1 to define a self-opening feature in such closure cap;

FIGURE 3 is a greatly enlarged cross-sectional view with portions broken away and essentially on the line 3 3 of FIGURE 2;

FIGURE 4 is a greatly enlarged cross-sectional view on the line 4-4 of FIGURE 2 with most of the associated bottle broken away;

FIGURE 5 is a fragmentary perspective view particularly illustrating the manner of lifting an integral pull tab defined in the outer layer of the closure cap of FIG- URE 1;

FIGURE 6 is an enlarged fragmentary cross-sectional view essentially on the line 6-6 of FIGURE 5 and particularly showing the position of the integral pull tab prior to severing away a pair of tear strips defined adjacent opposite sides of a pull-out plug provided in the inner layer of the closure cap of FIGURE 1;

FIGURE 7 is a fragmentary perspective view similar to FIGURE 5 and illustrating the pull tab and adjoining plug immediately prior to severing such plug and pull tab away from the closure cap;

FIGURE 8 is a perspective view similar to FIGURE 1 and particularly illustrating a friction surface provided in the outer end portion of the integral pull tab to enable easier grasping and pulling of such pull tab;

FIGURE 9 is a greatly enlarged fragmentary crosssectional view similar to the left hand portion of FIGURE 4 and illustrating the friction surface of FIGURE 8 provided in the outer layer by embossing a part of the entire thickness of the multiple layer closure cap and also showing the construction of an associated sealing cork which was subsequently bonded against the inside surface of such closure cap;

FIGURE 10 is a greatly enlarged fragmentary crosssectional view similar to FIGURE 3 of the drawings and illustrating another embodiment lof a laminated construction wherein only three layers of material are utilized;

FIGURE 1l is a perspective view illustrating another embodiment of a self-opening closure of this invention used on -a can;

FIGURE 12 is a plan View of the top of the closure of FIGURE 11;

FIGURE 13 is an enlarged fragmentary cross-sectional view on the line 13--13 of FIGURE l2; and

FIGURE 14 is an enlarged fragmentary perspective view illustrating the top portion of the can of FIGURE 11 and the manner of severing away a part of its top closure to define a dispensing opening therein.

Description of illustrated embodiments Reference is now made to FIGURE l of the drawings wherein one exemplary embodiment of this invention illustrated as a closure in the form of a crown-type closure cap 20 is illustrated and such closure cap is fastened in position on an associated bottle 21 in a known manner. The exemplary bottle 21 has a substantially cylindrical lower portion 2,2 and an upwardly tapering neck 23 which terminates in an annular bead 24 provided at the top of the neck 23.

The closure cap 20 is provided with a suitable seal which is adapted to be compressed against the top surface of the annular bead 24 to provide a seal between the closure cap `20 and the bottle 21. Any suitable seal may be utilized such as a llow-in type plastic seal, an annular ring-type plastic seal, or a more conventional seal such as a cork seal. For purposes of illustration a cork seal designated by the reference numeral 27 is shown suitably fastened in position against the inside surface of the closure cap 20.

The closure cap 20 of this embodiment is formed of a plurality of structural layers suitably bonded together substantially throughout their entire adjoining surfaces and essentially in the manner illustrated in FIGURE 3 of the drawings. In particular, the plurality of layers comprise a comparatively thick inside layer 30' and a thinner outside layer 31; and, although the layers 30 and 31 may be suitably bonded together merely utilizing a suitable bonding material or layer therebetween (or a plastic film which serves as an interconnecting structural layer and bonding layer) in this example of the invention, the inner layer 30 has a bonding sealant or bonding layer 32` bonded to its top surface, the top layer 31 has a plastic iilrn 33 bonded to its lower surface, and the layers 32 and 33 have their associated exposed surfaces suitably bonded together to define the construction illustrated in FIG- URE 3.

The layers -33 may be bonded together in one operation; however, in some applications of this invention it may be desired to apply a comparatively tightly clinging plastic layer, such as polyethylene or the like, to the lower surface of the outer layer 31 prior to laminating the two prelaminated layers 31 and 33 against the layer 30 using the bonding layer 32. This technique provides a laminated construction in which it is easier to separate the outer layer 31 and its tightly clinging plastic film 33 from the remainder of the construction for reasons as will be apparent later in this specification.

The multilayer closure cap 20 has a substantially circular central portion 35 provided with a depending skirt 36 extending from the peripheral edge 37 thereof and the skirt 36 holds the closure cap 20` in position against the annular bead 24 of bottle 21. The closure cap 20 is easily installed in position in the usual manner and utilizing available standard equipment.

The closure cap 20 has a rst roughly U-shaped weakening line designated generally by the reference numeral 40 provided therein and such weakening line has a bight 41 and a pair of outwardly extending spaced apart legs each designated by the same reference numeral 42. The U-shaped weakening line 40 extends through the outer layer 31 of the closure cap 20 and may, as illustrated in FIGURE 3, extend through the plastic layer 33, if desired. The weakening line 4t) defines a pull tab which is designated generally by the reference numeral 43 which may be easily grasped by lifting the end portion thereof adjoining the bight 41 of the U-shaped weakening line 40 and pulling upwardly essentially in the manner illustrated in FIG- URE 5.

The closure cap 20 also has a second weakening line provided therein and designated generally by the reference numeral 45 and the weakening line 45 is formed in the inner layer 30 and defines what will be referred to as a pull-out strip or plug 46 for the closure cap 20. The weakening line 45 is formed in the layer 30 so that one end portion 47 of the plug 46 is arranged within the confines of the spaced apart legs 42 of the weakening line 40 so as to define a pair of severable strips each designated by the same reference numeral 50 adjoining opposite sides of the end portion `47 of the pull-out plug 46.

The closure cap 20 is easily opened by lifting the pull tab `43 and severing across the tear strips 50 essentially from the terminal ends of the legs y42 to opposite sides of the plug 46 whereupon the pull tab 43 is, in effect, directly connected to the plug 46. The plug `46 is then readily removed by continued pulling of the pull tab 43 which severs the outer layer 31 and its adjoining plastic layer 33 essentially along the periphery of the plug 46 defined by the weakening line 45. The manner in which the pull tab 43 is lifted and in which the tear strips 50 are severed to enable the plug 46 to be pulled out will be readily apparent from FIGURES 5-7 of the drawings.

As seen particularly in FIGURES 2 and 7 of the drawings the second weakening line 45 provided in this exemplary embodiment of the invention has a substantially U-shaped configuration dened by a second bight 52 and a second pair of outwardly extending legs extending from the bight 52 and each designated by the same reference numeral 53. The bight 52 and adjoining portions of the second pair of legs 53 are arranged within the contines of the terminal end portions of the leg portions 42 of the U- shaped weakening line 40 so that each tear strip 50 is arranged between an outer portion of an associated leg 42 and an inner portion of an associated leg 53.

In this example of the invention the bight 41 of the U- shaped weakening line 40 is formed in the closure cap 20 so that the associated terminal outer edge 56 of the pull tab 43 defined thereby is arranged immediately adjacent the outer periphery 37 of the circular portion 35 of the closure cap 20. In particular, the bight 41 of the weakening line 40' is formed so that in the completed cap 20 it is positioned in the depending skirt 36 a small distance beneath the peripheral circular edge 37 and as shown at 55 in FIGURE 4. As the depending skirt 36 of the cap 20' is formed on suitable forming equipment the abovementioned positioning of the bight 41 of U-shaped weakening line 40 results in a space being provided immediately under the terminal edge 56 of pull tab 43 and such space enables a fingernail, or the like, to be easily inserted beneath the end portion of tab 43 adjoining its edge 56 whereupon the p-ull tab 43I may then be easily grasped and pulled upwardly in the manner illustrated in FIGURE 5 of the drawings.

Any suitable wea-kening technique may be utilized in dening the =Ushaped weakening lines 40 and 45 such as scoring, cut-scoring, etc.; however, in this example of the invention the weakening lines 40 and 45 are formed by continuous U-shaped cut lines. Accordingly, the weakening lines 40 and 45 will be referred to as out lines or cuts hereinafter in this specification and their respective bight and outwardly extending leg portions will also be referred to as cut portions.

The outwardly extending legs 42 of the U-shaped cut 40 preferably extend substantially diametrically across the entire circular portion 35 of the closure cap 20. In addition, the U-shaped cut 45 has its closed end portion delined in the circular portion 35 of closure cap 20 so that end portion 47 of plug 46 is thus formed in circular portion 35. Also, the outwardly extending legs 53 of the U-shaped cut 45 are formed so that they extend across practically the full height of the depending skirt 36 and each leg 53 has a terminal end which terminates at a point designated by the reference numberal 60v which is spaced above the terminal lower edge 61 of the depending skirt 36 The amount of metal in the cap 20 remaining between each point 60 and the lower edge 61 of the skirt 36 is comparatively small as will be readily apparent from the drawings and may be easily severed away essentially as illustrated in FIGURE 7, wherein the metal adjacent one side of the plug 46 is shown severed away and the metal adjacent the opposite side of such plug is shown intact, merely for purposes of illustration. The closure cap 20 is easily removed after completely severing away the plug 46; i.e. also severing away the attached side in FIG- URE 7, whereupon it is a simple matter to merely push upwardly against the lower edge 61 of the skirt 36 and remove the closure cap 20 from the bottle 21.

The U-shaped cut 45 has a slit 63 extending transverse to the bight 52 thereof and in a direction opposite from the direction of its outwardly extending leg portions 53. The slit 63 enables easier lifting of the closure cap 20 away from the bottle 21 once the pull tab 43 and plug 46 have been severed free by, in effect, enabling easy outward expansion of the skirt 36 away from the annular bead 24.

In this example of the invention the terminal end of each leg portion 53 of cut 45 terminates at point 60 with in each instance is spaced above the lower edge 61 of the depending skirt 36; however, it will be appreciated that in some applications of this invention it may be desirable to extend one leg of the cut 45 across the full height of the depending skirt 36 and to the lower edge 61 while terminating the other leg portion 53 at a point which may be higher than point 60 above edge 61. With such an arrangement it will be appreciated that one side of the severed strip assembly comprised on the interconnected pull tab 43 and plug 46 will be severed away essentially in the manner illustrated in FIGURE 7 and the other side will remain attached and upon further outward pulling of the pull tab 43 the multiple layer closure cap 20 is easily lifted away from the top of the bottle 21 essentially in one piece and without necessitatingr any pushing against the lower edge 61 of the depending skirt 36. In addition, it will be appreciated that with such an arrangement a slit similar to slit 63 may be provided 'and will enable easier pulling away of the multilayer closure cap 20 from the bottle 21 by enabling a spreading of the skirt 36 substantially radially outwardly from the annular bead 24.

Another exemplary embodiment of this invention is illustrated in FIGURES 8 and 9 of the drawings wherein a closure cap similar to the closure cap 20 is shown installed in position on a bottle which is substantially identical to the previously described bottle 21. Therefore, the bottle illustrated in FIGURES 8 and 9 and component portions thereof will be given the same reference numeral as previously and not described again in detail.

The closure cap of the embodiments of FIGURES 8 and 9 is very similar to the closure cap 20. Therefore, if will be designated by the same reference numeral 20 `followered `by the letter designation A and similar component parts thereof will also be given the same reference numeral as previously also followed by the letter designation A and not described in detail. For ease of presentation and quick cross reference the various structural layers of cap 20A will not be given a letter designation but will be given the same numeral designation as corresponding layers ofthe cap 20.

The only difference between the closure cap 20A and closure cap 20 is that the terminal outer end portion of the pull tab 43A is provided with a friction surface such as an embossed or raised surface portion to enable easier grasping and pulling thereof to provide an opening in closure cap 20A and thus open the bottle 21. The embossing may be achieved so that only the outer layer 31 is embossed prior to laminating the outer layer in position and prior to providing the U-shaped cut 40A in such outer layer; however, in this exemplary embodiment of the invention all layers of the cap 20A are, in effect, embossed or provided with ridges simultaneously with the forming of the skirt 36A as shown at 65A in FIGURE 9 of the drawings.

In a similar manner as previously described in connection with the closure cap 20 a suitable seal in the form of a cork sealing disc or seal 27A is fastened against the inside surface of the closure cap 20A and the cork seal 27A is preferably fastened in position after the embossing action is achieved. Therefore, the seal between the closure cap 20A and the annular bead 24 is not adversley effected.

Provision of the embossed area indicated at 65A also enables the pull tab 43A to be lifted in an easier manner away from its adjoining surface layer. Further, there is a tendency during the embossing action for the bight portion 41A of U-shaped cut 40A to be pulled further away yfrom its adjoining depending skirt 36A thereby making it easlier to insert a fingernail, or the like, beneath the terminal outer edge of the pull tab 43A to thereby enable easy grasping and lifting thereof.

Reference is now made to FIGURE 1U of the drawings wherein a fragmentary sectional view is illustrated of another arrangement of a laminated construction which may be utilized to form an improved closure of this invention, such as closure cap 20, closure cap 20A, or the end closure for a can to be described later in this specification. Basically, the laminated construction illustrated in FIGURE 10 utilizes an outer layer which is also designated by the reference numeral 31, an inner layer 30 which is thicker than the outer layer 31, and a dual function sealing and bonding layer in the form of a single thickness plastic film 33 arranged between the layers 30` and 31. Thus, it is seen that in the construction of FIG- URE 10 the separate bonding layer has been eliminated; further, it will be seen that a cut line designated by the numeral 40B and similar to cut line 40 is provided in the top layer 31 and a cut line 45B similar to cut line 45 is provided in the lower layer 30. The cooperating arrangement of the various cut lines and the overall construction of a closure made utilizing the laminated construction of FIGURE 10 may be substantially similar to the closure caps 20 and 20A previously described and thus `a detailed showing or description of a closure cap, or the like, made using the construction of FIGURE 10 will not be made.

Another exemplary embodiment of this invention is illustrated in FIGURES 11-14 of the drawings wherein an improved self-opening closure is provided in association with a substantially cylindrical can designated by the reference numeral 70. The can 70` has a cylindrical side wall 71 land a pair of oppositely arranged end closures shown as a bottom closure 72 and a top closure 73. The top closure 73 has a peripheral flange 74 defining a chime for the can 70 and the liange 74 is of conventio'nal construction and may be lfastened to the upper end of the cylindrical side wall 71 in a known manner and thus will not be described in detail, The top closure 73 also has an integral cap-like portion indicated generally by the reference numeral 75 provided substantially in the center thereof.

The top closure 73 of this exemplary embodiment of the invention is formed of a multilayer construction which is shown in FIGURE 13 and is substantially identical to the construction shown in FIGURE 3 and utilized to define the closure cap 20. Therefore, for ease of presentation and ready reference thereto the various layers of the laminated construction of FIGURE 13 will be designated by the same reference numerals as corresponding layers of FIGURE 3 and a detailed description will not be presented in connection with FIGURE 13.

In addition, it will be appreciated from the drawings that the arrangements of the various cuts provided in the end closure 73 are quite similar to various cuts provided in the closure cap 20. Thus, the detailed presentation of the various cuts, their cooperating configuration land arrangements, etc. will bevcomparatively brief in connection with this latter embodiment of the invention.

The top closure 73 has a substantially U-shaped cut provided therein and cut 80 has a bight portion 81 adjoining a peripheral circular edge 79 of the cap-like portion 75 and a pair of outwardly extending legs 82. The U-shaped cut 80 defines a pull tab 83 which is easily grasped and pulled in a similar manner as pull tab 43 described in connection with closure cap 20. In addition, it will be seen that the pull tab 83 has a friction surface provided on its outer end portion which is designated by the reference numeral 84. The friction surface 84 enables easy grasping and pulling of pull tab 83 and may be defined by embossing, or the like. The top closure 73 also has 'another weakening line designated generally by the reference numeral 85 which extends through the lower layer 30 and in this example of the invention is arranged in a closed-loop path and defines and approximately oval pullout plug designated by the reference numeral 86.

The pull-out plug 86 has an end portion 87 thereof arranged substantially between the outwardly extending leg portion 82 of the U-shaped cut 80 so as to define a pair of tear strips each designated by the reference numeral 90 and arranged onopposite sides of and `adjoining the end portion 87 of the plug 86. In addition, the plug 86 is formed in the top closure 73 so that its end portion 87 extends into the main planar portion of the substantially cap-shaped central portion 75 of closure 73 and a part of the plug 86 extends vertically along the depending cylindrical portion 91 provided. in the cap portion 75. The outer end portion of plug 87 is formed in an annular strip 92 which extends between the lower edge of the cylindrical portion 91 and the peripheral outer flange 74,

As will be apparent from FIGURES l2 and 14 of the drawings, the cut 85 through inner layer 30 defining the peripheral outline of the pull-out plug 86 is `arranged in a closed-loop path as previously mentioned. Thus, it will be appreciated that upon grasping the pull tab 83 and pulling outwardly the outer layers 31 and 33 of tab 83 are separated from the bonding layer 32 and the continued pulling of the pull tab 83 results in the pull-out plug 85 being completely severed from the top closure 73 to provide a dispensing opening 93 through which the contents of the can 70 may be easily dispensed.

Each of the various container closures presented in this specification is made in the form of a laminated construction which has high structural strength and is self opening; yet, each of such closure may be produced more economically than the presently known closures whether of the type provided for bottles, cans, or jars because a lesser quantity of structural material (such as metal, for example) is required for a given strength closure cap.

By way of example, some typical thicknesses will now be given for the various layers of an exemplary laminated construction which has been successfully used to form a container closure. In such exemplary laminated construction an inner layer .006 inch thick and made of metal containing aluminum was utilized, the adjoining layer 32 was in the form of an adhesive or bonding sealant .002` inch thick, the next layer 33 was plastic film of polyethylene .002 inch thick, and the top layer 31 was made of metal foil containing aluminum having a thickness of .004 inch. The dimensions presented herein are only presented by way of example and it is to be understood that such dimensions may be varied as desired and depending on the particular application of a closure made in accordance with this invention.

From the above exemplary dimensions it is seen that the total amount of metal containing aluminum which is utilized is .010 inch thick. By contrast, most of the currently used closure caps made of a single thickness construction and using the same metal as used herein for layers 30 and 31 are each .012 inch thick or greater. Thus, it will be appreciated that with the laminated construction of this invention there is a substantial metal cost saving because less metal is required. Also, present single thickness closures have weakening lines provided therein which tend to weaken the entire cap. By contrast, this invention provides a closure having optimum strength and rigidity because only certain layers are weakened while other adjoining layers are full-strength because they are kept intact. Also, the cooperating arrangement of the weakening lines assures provision of a self-opening closures without many of the disadvantages of such a self-opening closure.

It will also be appreciated that by utilizing a laminated -metal construction as described above and in which a plurality o-f layers are employed ywith at least one nontmetallic layer being sandwiched between a pair of metallic layers it is possible to cut the outer metallic layers in opposed directions in a continuous operation immediately prior to the blanking and forming of a closure cap or end closure, as the case may be, to define the self-opening feature, whereby considerable cost saving is realized during manufacture. By way of contradistinction, many previously proposed self-opening closures require separate pull tabs, or the like, or must be manufactured in separate operations which result in added costs.

In the examples of this invention presented herein, the plastic film 33 has been described as being in the form of a thermoplastic film such as polyethylene, or the like. However, it will be appreciated that any suitable plastic material may be utilized.

The bonding sealant or layer 32 may be in the form of any suitable adhesive which provides a -firrn high strength bond between an adjoining plastic layer and a metallic layer. One example of a bonding material which has been successfully utilized is a vinyl resin sold under the trade name of Elvax by the E. I. du Pont de Nemours and Company, Inc., of Wilmington, Del.

In both of the laminated constructions illustrated in FIGURES 3 and 13 of the drawings wherein the layer 32 is in the form of a bonding sealant or material, the plastic layer 33 is selected having characteristics which cause it to remain tightly adhered to the lower surface of the layer 31 during the process of lifting the associated pull tab. The plastic coating or layer 33 on the outer layer 31 not only increases the tear resistance and strength of the pull tab b-ut also helps reduce sharp edges which makes the pull tab less likely to cut ones fingers during the opening process. The thickness of the plastic layer 33 may be `made any desired amount and with the utilization of the plastic layer, whether in a laminated construction where only a plastic layer is sandwiched between a pair of metallic layers or in a construction where a bonding layer is also utilized, it is easier to provide cuts in the inner and outer metallic layers in opposed directions without critically weakening the associated closure and without special concern for material tolerances because the plastic layer 33, in effect, compensates for thickness variations and wear in the cutting tools used to form the various cuts to enable an efficient and continuous high volume operation.

As previously indicated the inside layer 30' is generally the thicker layer of the laminated construction and in the case of a bottle its thickness is selected to enable crimping thereof against an annular bead of an associated bottle so that a firm attachment is provided. However, it will be appreciated that the outer layer 31 also backs up and provides added strength for the inner crimping layer to provide a closure having a high degree of structural rigidity.

The improved self-opening closure of this invention whether in the form of a bottle cap or and end closure for a can may be formed utilizing standard equipment and lends itself to -manufacture using mass production techniques.

While present exemplary embodiments of this invention have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. A self-opening closure for a container comprising, a plurality of structural layers bonded together throughout their adjoining surfaces to define a laminated construction and comprising an inner layer and an outer layer, a. first roughly U-shaped weakening line having a first bight and a first pair of spaced apart legs provided in said outer layer and defining an integral pull tab therebetween, and a second weakening line in said inner layer defining an integral pull-out plug in said closure, said second weakening line being formed in said inner layer so that one end portion of said plug is arranged within the confines of said spaced apart legs to define a pair of severable strips in said closure adjacent opposite sides of said one end portion, said closure being easily opened by lifting said pull tab and severing across said tear strips whereupon said pull tab is directly connected to said plug which is readily removed by continued pulling of said pull tab which severs said outer layer along the periphery of said plug.

2. A closure as set forth in claim 1 in which said second weakening line comprises a second roughly U-shaped weakening line having a second bight and a second pair of outwardly extending legs, said second bight and adjoining portions of said second pair of legs being arranged within the confines of the terminal end portions of said first pair of legs to define said one end portion of said plug.

3. A closure as set forth in claim 1 in which said plurality of structural layers further comprises a plastic layer arranged between said inner and outer layers and said inner and outer layers are made of a metallic material.

4. A closure as set forth in claim 1 in which said plurality of layers further comprises a plastic layer bonded against the inside surface of said outer layer and a bonding layer bonded between said plastic layer and said inner layer, said inner and said outer layers being made of a metallic material.

5. A closure as set forth in claim 1 in which said outer layer comprises a layer of metallic foil, said inner layer comprises a thicker metal layer, and said plurality of layers further comprises a layer made of a thermoplastic material arranged between said inner and outer layers.

`6. A closure as set forth in claim 1 in which said first and second weakening lines are each in the form of a continuous cut with each cut being provided in an associated layer.

7. A closure as set forth in claim 1 in which said outer layer comprises a layer of metallic foil, said inner layer comprises a thicker metal layer, said plurality of layers further comprising a layer made of a plastic material arranged between said inner and outer layers, and said first and second weakening lines are each inthe form of a continuous cut with each cut being provided in an associated layer.

8. A closure as set forth in claim 7 and further comprising a friction surface on the outer end portion of said pull tab, said friction surface enabling easier grasping and pulling of said pull tab.

l9. A closure -as set forth in claim 7 and further comprising a fric-tion surface on the outer end portion of said pull tab, said friction surface comprising a plurality of spaced apart ridges formed by embossing all of the layers of the laminated construction within the confines of said first cut and said friction surface enabling easier grasping and pulling of said pull tab.

10. A closure as set forth in claim 7 in which the second cut is roughly lU-shaped having a second `bight and a second pair of outwardly extending legs, said second bight and adjoining portions of said second pair of legs being arranged within the confines of the terminal end portions of the first pair of legs of the first cut to define said one end portion of said plug.

11. A closure as set forth in claim 7 in which the second cut is formed in a closed-loop path and has one end portion thereof arranged within the confines of the terminal end portions of the first pair of legs of the first cut to define said one end portion of said plug.

12. A closure as set forth in claim 9 in which said closed-loop path of said second cut is roughly in the shape of an oval.

13. In combination: a container and a self-opening closure for said container, said closure comprising, a plurality of structural layers bonded together throughout their adjoining surfaces to define a laminated construction and comprising an inner layer and an outer layer, a first roughly U-shaped we-akening line having a first bight and a first pair of spaced apart legs provided in said outer layer and defining an integral pull tab therebetween, and `a second weakening line in said inner layer defining an integral pull-out plug in said closure, said second weakening line being formed in said inner layer so that one end portion of said plug is arranged within the confines of said spaced apart legs to define a pair of severable strips in said closure adjacent opposite sides of said one end portion, said closure being easily opened by lifting said pull tab and severing across said tear strips whereupon said pull tab is directly connected to said plub which is readily removed by continued pulling of said pull tab which severs said outer layer along the periphery of said plug.

14. A combination as set forth in claim 13 in which said container is defined as a bottle having a neck provided with an outwardly projecting annular bead at the top thereof and said closure is defined as a crown-type closure cap having a circular and substantially planar top portion and a skirt depending from the peripheral edge of said circular top portion, said skirt holding said cap on said bottle by clamping tightly against said annular bead.

15. A combination as set forth in claim 14 in which said first bight is defined immediately adjacent said peripheral edge of said top portion and said first pair of legs extend substantially diametrically across said top portion, and said second weakening line comprises a second roughly U-shaped weakening line having a second bight and a second pair of outwardly extending legs, said second bight and adjoining portions of said second pair of legs being arranged in said top portion within the confines of the terminal end portions of said first pair of legs to define said one end portion of said plug and the outer end portion of each of said second pair of legs extending substantially vertically downwardly along said skirt.

16. A combination as set forth in claim 15 in which, said plurality of structural layers further comprises a plastic layer arranged between said inner and outer layers, said inner and outer layers are made of a metallic material, and said first and second weakening lines are each in the form of a continuous cut with each cut being provided in an associated layer.

17. A combination -as set forth in claim 15 in which said closure cap further comprises a friction surface on the outer end portion of said pull tab, said friction surface enabling easier grasping and pulling of said pull tab.

18. A combination as set forth in claim 15 in which said closure cap further comprises a slit in said inner layer extending transverse to said second bight and in a direction opposite from the direction of said second pair of legs, said slit enabling easier lifting of the closure cap away from said bottle upon pulling out said plug by allowing easier outward expansion of said skirt.

19. A combination as set forth in claim 15 in which the terminal end of each of said second pair of legs is spaced immediately above the lower edge of said skirt and upon pulling out said plug a vertical strip is severed completely away from said skirt enabling said cap t0 be easily lifted away from said bottle.

20. A combination as set forth in claim 15 in which the terminal end of one of said second pair of legs is spaced above the lower edge of said skirt and the terminal end of the other of said second pair of legs coincides with said lower edge and upon pulling out said plug one side thereof adjoining said other of said second pair of legs remains attached to said closure cap enabling said closure cap to be lifted away from said bottle in one piece.

21. A combination as set forth in claim 13 in which said container is defined as a cylindrical can and said closure is defined as an end closure therefor.

22. A combination as set forth in claim 13 in which said container is defined as a cylindrical can land said closure is defined as an end closure therefor which has, a peripheral fastening flange, a raised cap-like portion substantially in the center thereof with said cap-like portion having a circular and substantially planar top portion and a cylindrical portion depending from the peripheral edge of said top portion, and an annular strip extending from the lower edge of said cylindrical portion to said peripheral fastening fiange.

2.3. A combination as set forth in claim 22 in which, said first bight is defined immediately adjacent said peripheral edge of said top portion with said first pair of legs extending substantially dia'rnetrically across said top portion, and said second weakening line is formed in a closedloop path and has one end portion thereof arranged within the confines of the terminal end portions of the first pair of legs of the first weakening line to define said one end portion of said plug and the opposite end portion of said second weakening line is defined in said annular strip so that upon removing said plug a dispensing opening is provided for `said can.

24. A combination as set forth in claim 23 in which, said plurality of structural layers further comprises a plastic layer arranged between said inner and outer layers, said inner and outer layers are made of a metalic material, and said first and second weakening lines are each 11 in the form of a continuous cut with each cut being provided in an associated layer.

25. A combination as set forth in claim 24 in which said closure cap further comprises a friction surface on the Outer end portion of said pull tab, said friction surface enabling easier grasping -and pulling of said pull tab.

26. A combination as set forth in claim 24 in which said outer layer comprises a layer of metallic foil, said inner layer comprises a thicker metal layer and said plulo rality of layers further comprises a plastic layer bonded against the inside surface of said outer layer and a sealout layer bonded between said plastic layer and said inner layer, with said rst and second weakening lines each being in the form of a continuous cut.

References Cited UNITED STATES PATENTS 3,260,395 7/1966 Ellis 21S-46 3,276,613 10/1966 Bozek 21S-46 GEORGE T. HALL, Prima/'y Examiner.

U.S. Cl. X.R.

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