US3768692A

US3768692A - Container easy-open structure

Info

Publication number: US3768692A
Application number: US00073344A
Authority: US
Inventors: W Saunders
Original assignee: National Steel Corp
Current assignee: National Steel Corp
Priority date: 1970-09-18
Filing date: 1970-09-18
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30
Also published as: NL7112849A; GB1365387A; FR2106621A3; FR2106621B3; DE2146584A1

Abstract

Double-lever action, easy-open container structure with a unitary rivet securing the working end of a tab opener in aligned relationship with a starter section of an outer scoreline which defines a removable area. The direction of the outer scoreline from the narrow starter section through a wedge-shaped portion provides for a shearing action along the scoreline in place of the tensile stress breakage required by the prior art. Arcuate ribs assist in maintaining the shearing action by preventing bulging of the removable wall portion. A chisel pointed tab opener concentrates force to facilitate initial rupture.

Description

O Umted States Patent 1191 1111 3,768,692 Saunders Oct. 30, 1973 [54] CONTAINER EASY'OPEN STRUCTURE FOREIGN PATENTS 0R APPLICATIONS [751 Invenm" William Saunders Weimm, 1,545,647 7 1967 France 220 54 [73] Assignee: National Steel Corporation, Primary ExaminerGeorge T. Hall Pittsburgh, Pa. Attorney-Shanley and O'Neil [22] Filed: Sept. 18, 1970 [57] ABSTRACT [21] Appl. No.: 73,344

Double-lever action, easy-open container structure I with a unitary rivet securing the working end of a tab [52] US. Cl. 220/54 opener in aligned relationship witha Starter Section f [51] Int. Cl B65d 17/20 an outer sc'oreline which d fi a removable area of Search The dire tion of the outer coreline from the narrow 215/46 A starter section through a wedge-shaped portion provides for a shearing action along the scoreline in place [56] Reerences Cited of the tensile stress breakage required by the prior art. UNITED STATES PATENTS Arcuate ribs assist in maintaining the shearing action 3,341,055 9/1967 Radford 220/48 y Preventing bulging 0f the removable Wall P 3,616,961 11 1971 Mallorca 220 54 A chisel pointed tab Opener concentrates force to 3,478,9l8 Ill 1969 Zundel 220/54 cilitate initial rupture. 3,593,875 7/1971 Fraze 220/54 3,527,378 9/1970 Scharf et al 220 54 9 Claims, 14 Drawlns Flgures PATENTEDucr 30 I975 3.768.692

v SHEET 10F 3 INVENTOR WILLIAM T. SAUNDERS F|(3.4 QQ'M ATTORNEYS PATENTEDUEHOIHB 3,768,692

INVENT WILLIAM T. SAU S Q BY M w' m ATTORNEYS PAIENTEDUMOIQB 3,768,692 SHEET 30F 3 INVENTOR WILLIAM T. SAUNDERS BY MWO'MLLQ ATTORNEYS CONTAINER EASY-OPEN STRUCTURE This invention is concerned with easy-open structure for containers. A specific interest is the category of easy-open structures which have been referred to as disc pull-out type. The invention includes improved double-lever action concepts, novel scoreline configurations, novel opening members, and novel reinforcing means which facilitate easy removal of scored portions of container walls.

The disc pull-out concept generally encompasses removal of a portion of a wall of a container as a panel, that is without forming a spiral of metal. An early embodiment of the disc pull-out concept is shown in the patent to Khoury issued May 30, 1967, US. Pat. No. 3,322,296.

Initially disc pull-out lids were limited to a single lever action. One disadvantage of the single lever action is that the metal on the inner side of the rivet is placed under tension making initial rupture difficult. Providing a double-lever action, through use of a second scoreline on the inner side of the rivet eliminates the effect of this tension.

Other disadvantages of prior disc pull-outs are related to upward bulging of an endwall panel during pull-out. Endwall profiling as disclosed in the patents to LaCroce et al US. Pat. No. 3,430,802 and Zundel US. Pat. No. 3,478,918 has not overcome these disadvantages. The problem is that the metal along the scoreline in each is placed under tension and it is necessary to overcome the tensile strength of the residual metal along the scoreline to remove the scored portion. The present discoveries which overcome such difficulties of the prior art include novel scoring configurations, novel profile configurations, and an improved opening member. Each helps provide an ease in opening of a container not available previously in the hand openable container art.

In making a detailed disclosure of a specific embodiment of the invention, a full-open" type of end-wall configuration will be shown and described; however, the teachings of this invention need not be limited to endwalls nor so-called full-open configurations. Individual views of the accompanying drawings relied on in making a detailed disclosure are identified briefly as:

FIGS. 1 and 2 are partial views of prior art pull-out container structures,

FIG. 3 is a planar view of easy-open container structure embodying the present invention,

FIG. 4 is an enlarged view of a portion of the structure of FIG. 3,

FIGS. 5 through 8 are sequential operation views for depicting operation of the present invention,

FIG. 9 is a perspective view of a container endwall portion after removal in accordance with the present invention,

FIG. 10 is a side elevation of a container endwall portion after removal in accordance with the teaching of the present invention,

FIG. 11 is a top plan view of a tab opener of the present invention,

FIG. 12 is a bottom plan view of the tab opener of FIG. 11,

FIG. 13 is an enlarged plan view of a portion of the tab opener of FIG. 11, and

FIG. 14 is an enlarged side elevational view of a portion of the tab opener of FIG. 11.

Being required to overcome the tensile strength of the residual metal along the outer scoreline .of the removable wall portion has been one of the main difficulties of prior disc pull-outs. With a disc pull lid, after initial puncture, opening of the container is continued by pulling back on the tab opener. In the prior art it was necessary to place the metal along the outer scoreline under tensile stress to cause breakage. With the usual container sheet metals, this requires considerably more force than that required by the present invention because the present invention provides a shearing" action of the metal along the scoreline. The metal is sheared (or ripped or torn) along the scoreline, not pulled apart under tension; this ease of tearing thin sheet metal along the scoreline, while maintaining disc pull-out advantages, is a major contribution of the present invention.

Referring to the prior art showing of FIG. 1, it is seen that after initial puncture at 20, the metal must be separated along the scoreline in the directions indicated by arrows 21 and'22 by backward pulling on tab opener 23. With the widely diverging directions shown, in pulling backwardly on the tab opener breaking along the scoreline can only occur by placing the metal in the scoreline under tension. This drastically limits the type of metal, metal gage, amount of scoring, and the like, operable for normal consumer uses.

FIG. 2 shows a prior art configuration employing an inner scoreline with terminating

ends

25 and 26. A problem of overcoming tensile strength similar to that of FIG. 1 exists because the ends of the inner scoreline at 25 and 26 lead to a concentration of force at these points which causes the endwall to bulge outwardly. Such outward bulging presents and maintains a configuration such that the scoreline residual metal must be pulled apart under tension.

Results differ drastically with the present invention shown in planar view of a container endwall 28 in FIG. 3. Endwall 28 is scored with an outer scoreline defining a removable area suitable for full-open uses, notwithstanding a predetermined inward spacing of portions of such outer scoreline to provide unusual advantages. This outer scoreline includes: a small-radius starter section 29, a wedge-shaped portion formed by

rectilinear legs

30 and 31, and a semi-circular portion 32. Starter section 29 is at the apex of

legs

30 and 31. Semicircular portion 32 is in closely spaced relationship to the outer periphery of the endwall 28. As indicated at 33 a curved intermediate portion interconnects each leg to the semi-circular portion.

An inner scoreline exists beneath the tab opener and will be described later.

Tab opener 34 includes a working end 35 and a handle end 36; it defines a finger opening 37 which is circular in configuration. Tab opener 34 is held to removable portion 38 of the endwall by rivet 39 which, in the case of sheet metal, is usually unitary and formed from metal of the removable area 38.

Raised protrusions 40 and 41 substantially constrain pivotal movement of tab opener 34 around unitary rivet 39 so as to maintain alignment of the working end of tab opener 34 with the matching configuration of starter section 29.

A significant contribution toward maintaining a shearing action during the early pull-back" stages stems from the wedge-shape configuration of the outer scoreline and from the configuration of reinforcing ribs and their placement substantially within the wedgeshaped portion of the scoreline. Note that this profiling for the endwall in the form of

radius ribs

44, 45 and 46 has predominantly arcuate configurations in plan view. These arcuate ribs, flat curved about a far removed center, aid the specially shaped score in providing shear action by holding down the central portion of the removal panel and preventing the bulging of the prior art.

Additional endwall profiling which aids in control of pull-out includes a finger placement depression 48 having a curvilinear border portion 49 and a substantially straight border portion 50. Also, note straight profile line 52 intermediate these two. Profile line 52 if extended as shown in dotted lines would meet terminating ends 53 and 54 of the semi-circular reinforcing rib 55.

In the enlarged view of FIG. 4, a portion of the specific embodiment of FIG. 3 is shown from the internal side of the container. Note the limited length of inner scoreline 60. Also, its close proximity to integral rivet 39 which it only partially circumscribes. Inner scoreline 60 circumscribes less than half of the rivet and generally less than about a third. In fact, the included angle between radii extending from the center of rivet 39 to the ends of inner scoreline 60 is preferably about 75. Dotted line 62 and inner scoreline 60 define a segment 64 of the endwall which is turned inwardly of the container during initial rupturing. A shaded impression area 66 designates the area of concentrated force for initial rupture of the outer scoreline. The working end of the tab 34 is aligned with the starter section 29 of the outer scoreline and the force is concentrated at such area which is as close as practicable to the scoreline starter section 29.

FIGS. through will be referred to in describing the sequence of steps involved in opening a container and the function of the individual elements of the struc ture designated. In these views the endwall and removable portion are shown without the tab opener for better viewing since it will be understood from the description of these figures how the functions of the tab opener come into play.

The plan view of FIG. 5 shows the endwall 28 with removable portion 38, the outer scoreline starter portion 29,

rectilinear scoreline legs

30 and 31, and semicircular scoreline portion 32 The removable area 38 can be divided into sections related to parts of the scoreline and the operations which take place. The first section is segment 64 which is folded downwardly into the container as indicated by FIG. 6 during the initial opening operation when the handle or input end of the tab opener is raised.

The angular, wedge-configuration portion of the removable panel from segment 64 through the arcuate rib profiling portion to the ends of the

rectilinear legs

30 and 31 has been designated wedge section 68. The radius ribs stiffen this section during removal to prevent outward bulging.

An intermediate segment 72, between the wedge section 68 and the section bounded by semi-circular scoreline portion 32, extends roughly to the line 52. Note in FIG. 10, which is a profile of the removed end-wall area, that intermediate segment 72 takes on a curved configuration in profile during removal.

The remaining section is held planar by the semicircular profile rib 55. This semi-circular portion is the last portion of the lid removed.

In operation, raising of the handle (i.e., the working end of the tab) causes rupture of the inner score-line 60 and the starter portion 29 of the outer scoreline. This initial rupture causes segment 64 to be turned inwardly of the container as shown in FIG. 6.

After this initial rupture the tab is pulled backwardly and the removable portion separates from the endwall along the

rectilinear legs

30 and 31 as shown in FIG. 7. During this portion of the action the

profiling ribs

44, 45 and 46 not only prevent doming or bulging outwardly of the lid but tend to effect an inward configuration on the lid. Because of the angle along

lines

30 and 31, the metal can be parted in shear along the

scoreline legs

30 and 31, rather than being stretched apart in tensron.

As the

scoreline legs

30 and 31 meet the curved portion 33 of the outer scoreline the lid is folded backwardly as indicated by FIG. 8. During this phase of the removal, the metal along the scoreline continues to be torn readily in shear rather than being separated under tension. The intermediate segment 72 takes on the curved configuration illustrated by the perspective view of FIG. 9 and the profile view of FIG. 10. This backward curving is terminated by the interaction of several elements, in combination, the reinforcing line 52 within the finger depression and the

tips

53 and 54 of the reinforcing rib 55 which lie along an extension of the reinforcing line 52. With continued backward pulling the remainder of the endwall, section 80, is removed with the semi-circular reinforcing rib 55 maintaining this section in planar form. Profile view 10 shows this planar configuration as well and the usual configuration of the various sections of the lid after removal.

The elements and features described combine to provide an ease of opening not previously available. The inner scoreline, ruptured by initial movement of the workingend of the handle by class 2 lever action eliminates the back tension which in some earlier structures inhibited the class 1 lever action for the outer scoreline. Metal at starter portion 29 is ruptured by class I lever action. Note that this portion is aligned with and partially circumscribes rivet 39. A concentration of force is thus possible which facilitates initial rupture.

A significant contribution to the easy-open characteristics of the present invention is made by a chisel pointed tab opener forming part of the present invention and shown in detail in FIGS. 11 through 14.

Referring to the top plan view of FIG. 11, the ring pull tab opener 34 includes working end 35, having a rounded configuration in plan conforming to the configuration of starter scoreline 29 of the outer scoreline of the wall. From the working end the tab opener 34 widens through the body portion 83 going toward the handle end 36. At the working end 35 is a chisel point 84, which will be described in more detail in relation to the enlarged views of FIGS. 13 and 14. At the handle end 36, a raised portion 86 is provided for ease in initial placement of a finger under the tab opener.

The tab opener 34 would conventionally be made from the material of the container wall to which it is at.- tached. Ordinarily this will be sheet metal of equal or greater strength than the sheet metal of the container. Since the tab opener is required to function as a lever,

it is purposefully strengthened by use of a wrap-around edge. The wrap-around feature is shown in the bottom plan view of FIG. 12. Edge metal of the tab handle is wrapped around and folded over along the entire outer periphery 88 and the inner periphery of the ring at 90. This provides longitudinal strength for the lever action of the tab opener and also protects the user in providing a smooth rounded edge for finger contact.

The forming of a chisel point in the wrap-around edge at the working end of the tab opener is. one of the novel features of the present invention. Details of the chisel point are shown in the enlarged views 13 and 14,

a top plan view and side elevation respectively. Utilizing wrap-around edge metal placed at the rounded working end 35, chisel point 84 is formed by depressing the metal at 84 while supporting the metal adjacent thereto at 86 and 87. The resultant chisel point 84 consists of a double thickness of metal with a slightly rounded point configuration 88. Support adjacent to this chisel point is provided by the double thickness flattened

portions

86 and 87. A high strength point able to withstand the concentration of force required to start opening results.

The chisel point concentrates force at the center of impression 66 shown in FIG. 4. Because of the starter action of the chisel point and concentration of force at the scoreline portion 29, initial rupture is facilitated. The shearing action described earlier facilitates further opening upon pulling back of the tab opener.

With the teachings of the present invention the depth of scoreline utilized can be reduced significantly. For example, when using flat rolled mild steel in the prior art for container end closures, no greater residual metal thickness than about 0.0025 inch has been practical or attempted. With the present invention residual metal thickness for flat rolled mild steel can be increased to 0.0035 inch, and higher, e.g., as high as 0.0038 inch while maintaining practical, easy-open features. Scoreline residual metal for other container sheet metals, such as aluminum, is correspondingly increased by the present invention.

The practical advantages of reduced depth scoring are longer tool life and reduction in scoreline repair requirements. With some protective coverings for steel, no scoreline repair is required because of the significant reduction in the depth of score. For example, with the chrome-chromium oxide coating of the flat rolled container stock known as Weirchrome (National Steel Corporation, Pittsburgh, Pa.) no repairing of an exterior surface scoreline is required when scoring in accordance with the present invention.

With the increased residual metal permitted by the present invention, heavier gage endwalls can readily be used, if required for endwall strength. However preferences taught for flat rolled mild steel are gages between about 65 and 90 pounds per base box, that is about 0.007 to 0.010 inch. With aluminum the thickness gages can be correspondingly thicker as required such as up to 0.012 inch and higher.

In the specific embodiment shown, when fabricated from flat rolled mild steel, the diameter of the rivet stem is about 0.1 inch while the rivet head has a diameter of about 0.125 inch. The radius of the starter section 29 is about 0.150 inch.

The invention is not limited to the specific endwall embodiment illustrated and other means may be provided for securing a tab opener to a container and for preventing pivotal movement of a riveted opener. The tab opener can also be other than the ring pull type. Other modifications, configurations, and materials than those mentioned are made possible by the teachings of the present invention, as described above, so that in determining the scope of the invention reference should be had to the appended claims.

What is claimed is: 1. Container easy-open structure comprising a container wall, an outer scoreline of diminished material thickness located on the container wall defining a removable area of such wall, such outer scoreline including an apex portion and a wedge-shaped configuration portion having legs deviating from such apex portion, the container wall comprising a sheet metal endwall and the removable area of such endwall comprising a major portion of such endwall to provide full-open uses for such container, the endwall being bounded by a periphery with the wedge-shaped configuration portion of the outer scoreline being spaced from such periphery and the remaining major portion of the outer scoreline being in close proximity and uniformly spaced from such periphery, an inner scoreline of diminished material thickness and predetermined limited length located within the removable portion of the container wall, an opening member, and securing means securing the opening member to the removable portion of the container wall, the securing means comprising a unitary rivet formed from metal of the removable area of the container wall, the opening member including a handle end in spaced relationship from the securing means and a working end adjacent to the securing means, the handle end and working end of the opening member being located on opposite sides of the securing means, the inner scoreline being located in close proximity to the securing means in a position to be ruptured throughout its length upon movement of the open ing member in a direction away from the container wall, the apex portion of the outer scoreline being located, adjacent to the securing means aligned with the working end of the opening member, at a position to be ruptured with continued movement of the handle end of the opening member in a direction away from the container wall, the outer scoreline being in close proximity and uniformly spaced from such periphery, an inner scoreline of diminished material thickness and predetermined limited length located within the removable portion of the container wall, an opening member, and securing means securing the opening member to the removable portion of the container wall, the securing means comprising a unitary rivet formed from metal of the removable area of the container wall, the opening member including a handle end in spaced relationship from the securing means and a working end adjacent to the securing means, the handle end and working end of the opening memher being located on opposite sides of the securing means, the inner scoreline being located in close proximity to the securing means in a position to be ruptured throughout its length upon movement of the opening member in a direction away from the container wall,

the apex portion of the outer scoreline being located, adjacent to the securing means aligned with the working end of the opening member, at a position to be ruptured with continued movement of the handle end of the opening member in a direction away from the container wall,

with metal along the wedge-shaped configuration scorelines being severed after such rupture by a tearing action as the opening member is pulled backwardly and away from the container.

2. The structure of claim 1 in which the limited length inner scoreline circumscribes less than one half of the unitary rivet and in which the inner scoreline is ruptured by class 2 lever action.

3. The structure of claim 2 in which the limited length inner scoreline comprises an arc of a circle centered on the unitary rivet, such are supporting an included angle of no greater than about 75.

4. The structure of claim 1 including means for constricting pivotal movement of the opening member about the unitary rivet.

5. Container easy-open structure comprising a sheet metal container wall,

an outer scoreline of diminished material thickness located on the container wall defining a removable area of such wall,

an inner scoreline of diminished material thickness located within the removable portion of the container wall, 7

an opening member,

securing means securing the opening member to the removable portion of the container wall,

the opening member including a handle end in spaced relationship from the securing means and a working end in close proximity to the securing means, the handle end and working end of the opening member being located on opposite sides of the securing means,

a portion of the outer scoreline defining a narrow width apex and the entire inner scoreline being located adjacent to the securing means at a position to be ruptured with movement of the handle end of the opening member in a direction away from the container wall,

the outer scoreline deviating from such apex along a wedge-shaped configuration,

rupture of the narrow width apex portion of the outer scoreline being by class 1 lever action and the rupture of the inner scoreline being by class 2 lever action, and

wall reinforcing rib means of arcuate configuration positioned to extend across the removable area of the container wall and located substantially entirely on the same side of the securing means as the inner scoreline in at least partial circumscribing relationship to the securing means.

6. The structure of claim 5 in which the container wall comprises an endwall including additional reinforcing means located within the removable portion of the endwall and circumscribed by a portion of the outer scoreline adjacent to and uniformly spaced from the outer periphery of the endwall, such additional reinforcing means being diametrically opposed to the portion of the outer scoreline ruptured initially by movement of the handle end of the opening member.

7. The structure of claim 6 in which the additional reinforcing means includes a depression in the container endwall at the handle end of the opening member, such depression including a substantially straight line configuration having a direction transverse to a diametrical line through the initially ruptured portion of the outer scoreline.

8. The structure of claim 7 in which the additional reinforcing means also includes a semi-circular rib spaced from and substantially concentric with the outer periphery of the endwall, the semi-circular rib terminating at both its ends at a location near extension of the straight line configuration of the depression below the handle end of opening member.

9. The structure of claim 5 including at least three arcuate reinforcing ribs.

* l k l v UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION In n isb William I. Saunders It is certified that error appears in the above-identified patent and that said Letters Patent are herebyeorrected as shown below:

ZClaim 1, Column 6, line 52, after wall, 'Fthe outer scoreline {being in close proximity and uniformly spaced from such Zperiphery," should be deleted;

Same claim, Column 6, lines 55 to the end of Column 6, inclusive, should be deleted;

lSame claim, Column 7, lines 1 through 13, inclusive, should be deleted.

Signed and sealed this 8th day of October 1974,

(sEAL) Attest: j McCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents FORMIPO'WSO (wss) USCOMM-DC Bean-P69 I .5. GOVERNMENT PRINTING OFFICE T959 0-365-334.

Claims

1. Container easy-open structure comprising a container wall, an outer scoreline of diminished material thickness located on the container wall defining a removable area of such wall, such outer scoreline including an apex portion and a wedge-shaped configuration portion having legs deviating from such apex portion, the container wall comprising a sheet metal endwall and the removable area of such endwall comprising a major portion of such endwall to provide full-open uses for such container, the endwall being bounded by a periphery with the wedge-shaped configuration portion of the outer scoreline being spaced from such periphery and the remaining major portion of the outer scoreline being in close proximity and uniformly spaced from such periphery, an inner scoreline of diminished material thickness and predetermined limited length located within the removable portion of the container wall, an opening member, and securing means securing the opening member to the removable portion of the container wall, the securing means comprising a unitary rivet formed from metal of the removable area of the container wall, the opening member including a handle end in spaced relationship from the securing means and a working end adjacent to the securing means, the handle end and working end of the opening member being located on opposite sides of the securing means, the inner scoreline being located in close proximity to the securing means in a position to be ruptured throughout its length upon movement of the opening member in a direction away from the container wall, the apex portion of the outer scoreline being located, adjacent to the securing means aligned with the working end of the opening member, at a position to be ruptured with continued movement of the handle end of the opening member in a direction away from the container wall, with metal along the wedge-shaped configuration scorelines being severed after such rupture by a tearing action as the opening member is pulled backwardly and away from the container.

3. The structure of claim 2 in which the limited length inner scoreline comprises an arc of a circle centered on the unitary rivet, such arc supporting an included angle of no greater than about 75*.

5. Container easy-open structure comprising a sheet metal container wall, an outer scoreline of diminished material thickness located on the container wall defining a removable area of such wall, an inner scoreline of diminished material thickness located within the removable portion of the container wall, an opening member, securing means securing the opening member to the removable portion of the container wall, the opening member including a handle end in spaced relationship from the securing means and a working end in close proximity to the securing means, the handle end and working end of the opening member being located on opposite sides of the securing means, a portion of the outer scoreline defining a narrow width apex and the entire inner scoreline being located adjacent to the securing means at a position to be ruptured with movement of the handle end of the opening member in a direction away from the container wall, the outer scoreline deviating from such apex along a wedge-shaped configuration, rupture of the narrow width apex portion of the outer scoreline being by class 1 lever action and the rupture of the inner scoreline being by class 2 lever action, and wall reinforcing rib means of arcuate configuration positioned to extend across the removable area of the container wall and located substantially entirely on the same side of the securing means as the inner scoreline in at least partial circumscribing relationship to the securing means.

9. The structure of claim 5 including at least three arcuate reinforcing ribs.