US3454185A - Easy opening can end - Google Patents

Description

July 8 1 9 69 o. L. BROWN ET AL 3,454,185

EASY' OPENING CAN END Filed Aug. 31. 1967 Sheet 47 lA/VfMfO/Qfi Omar Z. d awn flan 6. Pe/prr 54.741

July 8,1969 0. 1.. BROWN ET AL 3,454,1 5

E AISY OPENING CAN END 1 Filed Aug. 31, 1967 Sheet 3 of 2 0070/ 1. arm) 00 -I. Fe/er] gzm fza Arrows 2x;

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United States Patent 3,454,185 EASY OPENING CAN END Omar L. Brown and Don B. Peters, Dayton, Ohio, assignors, by mesne assignments, to Ermal 'C. Fraze, Dayton,

Ohio

Filed Aug. 31, 1967, Ser. No. 664,776 Int. Cl. B65d 17/20 U.S. Cl. 220-54 7 Claims ABSTRACT OF THE DISCLOSURE This disclosure describes an easy opening container including a container wall of sheet material having a line of weakness therein defining a removable wall segment at least partially removable from the container wall. A tab is attached to the removable wall segment and at least a section of the nose end of the tab extends across the line of weakness and overlies a relatively rigid wall segment of the container wall adjacent the line of weakness. The tab is operable as a lever to cause the nose end thereof to forcibly bear on the rigid wall segment to apply an outward lifting force to the removable wall segment to initiate rupture of the line of weakness. The removable wall segment is then removable from the container wall by the application of a pulling force to the tab.

BACKGROUND OF THE INVENTION As is well known, an easy opening container includes a container wall with a line of weakness such as a score line therein defining a removable wall segment or tear portion. A tab is connected to the tear portion .to remove the tear portion from the container wall. If the tab is of the'frontopening type, the nose end thereof bears on the tear portion and upon manipulation of the tab, initiates severance of the tear portion from the container wall.

Front-opening tabs are commonly used in easy opening containers of the full panel pull-out type. In full panel pullouts, the score line defines a removable panel which covers a major portion of the container wall and the tab is secured to and overlies the panel. The panel can be removed in a two step operation. First, the tab is pivoted to cause the nose end thereof to forcibly bear on the panel adjacent the score line to initiate rupture of the score line, by bending a paddle portion of the panel inwardly. Secondly, an outwardly directed pulling force is applied to the tab to remove the panel from the container wall.

Full panel pull-outs are often used to package vacuum packed products such as various types of nuts. When the tab is lifted during the first phase of tab operation, the score line is ruptured and a relatively large portion of the panel, commonly referred to as a paddle, is bent inwardly into the container to form a relatively large opening therein. Air now rushes into the container through such opening. As continuing the rupturing of the score requires only a little force, the differential air pressure acting on the removable panel coupled with the inward air movement are oftentimes sufiicient to pull at least a portion of the panel and the tab into the container. This effect, which is known as implosion occurs rapidly and often results in frightening the user and disruption or destruction of the product within the container. Furthermore, the pulling of the removable panel into the container may make the second phase of panel removal more difficult.

SUMMARY OF THE INVENTION The present invention eliminates the problem of implosion in easy opening containers by locking the can end against movement into the container. This invention teaches that the locking feature can be provided by securing the tab to the removable panel and allowing a por- Patented July 8, 1969 tion of the tab to overhang the score line and bear on the can end.

Specifically, a container wall is provided with a line of weakness or score line, which defines a removable wall segment or panel, and a tab is attached to the removable panel with the nose end thereof overhanging the line of weakness and a relatively rigid wall segment of the can end immediately adjacent the line of weakness. To remove the removable wall segment, the end of the tab remote from the nose end is lifted in conventional fashion to force the nose end of the tab downwardly to bear firmly against the rigid wall segment. The rigid wall segment has substantial resistance to bending so that it supports the nose end of the tab as the tab is being manipulated and is not bent inwardly into the container. As the rigid wall segment forms a support for the nose end of the tab, continued pivotal movement of the tab causes a lifting force to be applied to the removable panel through the attachment means which interconnects the tab and the removable panel. This lifting force is nearly a pure shearing force and as such facilitates rupture of the line of weakness. Ultimately, this lifting force initiates rupture of the line of weakness to form what may be described as a pressure equalizing opening in the container wall. At this instant, air may flow through this opening into the interior of the container. The rush of air into the container and the pressure dilferential act on the removable panel and tend to force the latter into the container. However, the rigid wall segment continues to support the nose end of the tab to prevent implosion. Thus, the rigid wall segment serves as a latch or lock to prevent drawing of the removable panel into the container and secondly as a relatively rigid support for the nose end of the tab to thereby allow the tab to initiate severance of the line of weakness through a lifting action on the removable wall segment.

The tab should provide a pivotal lever portion and also be quite strong in order to cause rupture of the line of weakness through a lifting action on the removable wall segment. Preferably, the tab is constructed of sheet metal and includes an attachment portion and a lever portion joined by a hinge to allow the lever portion to pivot relative to the attachment portion. The lever portion has a lifting or handle end and a nose end. The attachment portion is preferably connected to the removable wall with an integral rivet.

In a preferred embodiment, two rivets are utilized to connect the attachment portion to the removable panel to prevent pivotal movement of the tab relative to such wall segment. Preferably, the attachment portion and lever portion are joined by a fold portion which allows the lever portion to overly the attachment portion. A tab having these features has been found to be strong and well suited for removal of even the large panels.

Although the present invention is applicable to the use of front-opening tabs generally, it is particularly adapted to be embodied in a full panel pullout. In a full panel pullout, the score line defining the removable panel lies closely adjacent the peripheral attaching flange of the container. The region of the container wall between the score line and the peripheral attachment flange is too narrow to adequately support the nose end of the tab. The present invention teaches altering the shape of a portion of the score line to widen the region radially to form a ledge of sufiicient size to support the nose end of the tab. Although the ledge must be large enough to support the nose of the tab, it should be kept to a minimum size so that as much of the container wall as possible can be removed. To this end the score line may have a major portion in the form of a substantially complete circle and a minor portion extending between the ends of the major portion and forming, in effect, a chord of the major portion. The minor portion and the adjacent section of the attaching flange define the ledge. To further minimize ledge size, the nose end of the tab which bears on the ledge is preferably narrower than the body of the tab.

It is well known that the second phase of removal of a removable panel, during which an outward pulling force is applied to the tab, is substantially facilitated if the panel is curled outwardly. This is so because when the panel is curled an almost pure shearing force is applied to the score line to make continued severence thereof very easy. Another advantage of the present invention is that the outward lifting force supplied to the removable panel tends to curl the panel outwardly in a manner to substantially facilitate the second phase of panel removal.

The invention, both as to its organization and method of operation together with further features and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of an easy opening container wall embodying the teachings of the present invention.

FIG. 2 is a top plan view of a preferred form of tab for opening the easy opening container wall.

FIG. 3 is a bottom plan view of the tab.

FIG. 4 is an enlarged fragmentary sectional view taken along line 44 of FIG. 1 and showing how the tab is attached to the container wall.

FIG. 5 is an enlarged fragmentary sectional view taken along line 55 of FIG. 1 and showing the nose end or rupturing portion of the tab overhanging the score line.

FIG. 6 is an enlarged fragmentary sectional view similar to FIG. 5 showing the formation of the small pressure equalizing opening as a result of pivoting of the tab.

FIG. 7 is a view similar to FIG. 6 at the beginning of the second phase of panel removal.

FIG. 8 is an enlarged fragmentary plan view showing a second embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings and in particular to FIG. 1 thereof, reference numeral 11 designates an easy open container wall constructed in accordance with the teachings of this invention. Although other configurations are possible, the container wall 11 is circular in plan and has an attachment flange 13 for attaching the container wall to a can body (not shown) in a conventional manner. The container wall 11 has a line of weakness or score line 15 which lies closely adjacent the flange 13 and defines a removable panel 17 which covers substantially all of the area in plan of the container wall. A tab 19 is suitably secured to the panel 17 and is movable to remove the panel 17 from the container wall 11.

More particularly, the score line 15 has a major or circular portion 21 which substantially completely surrounds the panel 19 and a relatively short minor portion or chord portion 23 which interconnects the ends of the circular portion. In the embodiment shown in FIG. 1, the chord portion is a substantially straight line. The peripheral attaching flange 13 has a wall 25 (FIG. 4) which is generally perpendicular to the panel 17 and lies closely adjacent the major portion 23 of score line 15. The region of the container wall 11 between chord portion 23 of the score line 15 and the wall 25 defines a relatively rigid wall segment or ledge 27. The ledge is narrow radially and has a minimum circumferential dimension.

Tabs of various designs may be used with the present invention. In the embodiment illustrated, the tab 19 is constructed of sheet material such as sheet aluminum and has a handle portion 29 at one end thereof and a nose end 31 at the other end thereof extending across the chord portion 23. More particularly, the tab 19 has an upper layer or lever portion 32 (FIGS. 2-5) of sheet material and a lower layer or attachment portion 33 of sheet'material interconnected by a fold portion 35. The fold portion or a section thereof is sufficiently pliable to define a transverse hinge or hinge line to allow the lever portion 32 to pivot relative to the attachment portion. A peripheral region of the lever portion 32 is curled inwardly to form a peripheral reinforcing bead 37 and an adjacent circular region is curled outwardly to form an inner head 39 which surrounds a finger opening 41 in the tab. The lever portion 32 is longitudinally rigid and is strengthened by a longitudinal rib 43 and a transverse rib 45.

The attachment portion 33 has a pair of apertures 47 (FIG..4) therein which are located closely adjacent the fold portions 35 and through which hollow rivets 49 (FIGS: 4 and 5) pass to secure the tab 19 to the container wall 11. Use of the two rivets 49 prevents turning of the tab relative to the wall 11. The lever portion 32 has a pair of apertures 51 which are in registry with the apertures 47 therebelow to allow the insertion of a tool for staking the rivets 49. To facilitate removal of the panel 17 it is preferred that the rivets 49 be located as closely as possible to the score line 15. Accordingly, the apertures 47 are preferably positioned as closely to the fold portion 45 as the geometry of the tab will permit, and the rivets 49 are preferably of very small diameter, e.g. outside diameter. It has been found that by positioning the rivets 49 as closely as possible to the score line that the tendency of the panel 17 to curl upwardly in response to pulling of the tab is significantly increased. Such curling of the panel 17 causes the panel 17 to be easily sheared from the container wall 11.

The sheet metal of the tab 19 is lanced and formed to extend the longitudinal rib 43 forwardly to form the nose end 31 of the tab. As shown in FIGS. 23 the nose end 31 is much narrower than the remainder of the tab 19 and progressively narrows as it extends forwardly. As shown in FIG. 5, the nose end 31 curves downwardly and may be spaced slightly above the ledge 27 to allow some swinging movement of the tab 19 before it encounters the ledge 27. The nose end 31 has a lower face 54 which is engageable with the ledge 27. The rupturing portion 31 extends across the score line 15 and overlies the ledge 27 Upon lifting of the handle portion 29 of the lever portion 32, the lever portion pivots about the transverse hinge which may lie adjacent the juncture of the fold portion 35 and the layer 33, while the lever 32 of the tab remains longitudinally rigid. As the handle portion 29 is swung upwardly, the nose end 31 pivots downwardly to cause the surface 54 to engage the ledge 27 and forcibly bear thereon. The ledge 27 is relatively rigid and not subject to inward bending in ordinary use of the easy-opening container wall 11. Accordingly, the ledge 27 rigidly supports the nose end 31 of the tab 19.

As the handle portion 29 of the tab is lifted an additional amount, the nose end 31 bears with ever increasing force on the ledge 27 which continues to remain relatively rigid. As the nose end 31 of the tab is supported by the ledge 21 and the handle portion 29 is lifted further, the tab applies an outward lifting force on a section 55 of the panel 17 to which the attachment portion 33 of the tab is connected. That is, the tab applies a lifting force to the section 55 through the attachment portion 33 and the rivets 49. During this time, the ledge 27 deflects downwardly or inwardly only slightly and thus can be accurately said to remain substantially rigid. It should be noted that the attachment portion 33 and the rivet 49 apply a generally directly upwardly force to the panel 17 while the rupturing portion 33 applies a downward force to the ledge 27 and thus the section of the score line 15 intermediate the nose end 31 and the attachment portion 33 is subjected to substantially pure shearing force, which is highly effective in initiating rupture of the sheet material along the score line.

When the upward lifting of the handle end 29 of the tab 19 applies a suflicient force to the sheet metal along the score line, the severance of the panel 17 from the can end 11 is initiated and a pressure equalizing opening 57 is formed substantially as shown in FIG. 6. It should be noted that the section 55 of the panel 17 tends to curl or fold outwardly along the ruptured length of the score line 15. Thus, during the second phase of panel removal during which an outward pulling force is applied to the tab 19 as shown in FIG. 7, the panel 17 curls outwardly away from the can end 11 to thereby minimize the resistance to this second phase of removal of the panel.

The ledge 27 serves two very important functions. First, in the event that the can end 11 is utilized on a container having less than atmospheric pressure therein, the pressure equalizing opening 57 can be formed without danger of having the panel 17 and the tab 19 forcibly and suddenly drawn into the container. This is so because the ledge 27 supports the nose end 31 and serves, in effect, as a latch to lock the tab and panel 17 against inward movement into the container as a result of the pressure differential on opposite sides of the panel 17. Secondly, because the ledge 27 rigidly supports the nose end 31, the tab 19 is caused to apply an outward or upward lifting force on the section 55 of the panel 17 to thereby initiate the desirable outward curling of the panel during the initial phase of panel removal in which the lever portion 32 of the tab 19 is pivoted as shown in FIG. 6.

FIG. 8 shows a modification of the form of the invention shown in FIGS. 1-7 in which corresponding elements are designated with corresponding primed reference characters. As shown in FIG. 8 an easy opening container wall 11' has a score line 15' defining a removable panel 17. A tab 19, which is identical to the tab 19, is secured to the panel 17 by a pair of rivets 49. The score line 15' has a major portion 21 which forms almost a complete circle and a chord portion 61 which interconnects the ends of the major portion 21 to define, along with an attachment flange 13', a ledge 27. As shown in FIG. 8, the chord portion 61 curves inwardly slightly from the ends of the major portion 21 and then curves smoothly outwardly slightly beneath the nose end 31 of the tab 19 to form a small projection 63 in the panel 17'. The ledge 27' is identical to the ledge 27 except that the inner edge thereof which is defined by the chord portion 61 is curved slightly as shown in FIG. 8 rather than being straight as shown in FIG. 1. The rupturing portion 31' of the tab 19 extends across the chord portion 61 and overlies the ledge 27. Thus, the modification of FIG. 8 illustrates another way in which a suitable ledge may be provided for cooperation with the rupturing portion of the tab. The modification of FIG. 8 is operable as described above in connection with FIGS. 5-7.

Although exemplary embodiments of the invention have been shown and described, many changes, modifications, and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.

We claim:

1. In an easy opening container, the combintion of:

a container wall of sheet material having peripheral means for attaching the container wall to the container, said peripheral means being generally circular in plan;

a line of weakness in said container wall defining a panel removable from said container wall to define an opening in said container wall, said removable panel covering substantially all of said container wall, said line of weakness having a major portion forming a substantially complete circle and lying closely adjacent said peripheral means and a minor portion joining the ends of said major portion and generally forming a chord of said major portion, said small narrow ledge therebetween, said ledge having substantial resistance to inward bending;

a sheet metal tab having a lever portion and an attachment portion integrally joined by a fold portion with the sheet material of the tab between said lever and attachment portions being pliable to define a hinge to allow the lever portion to pivot about said hinge line relative to said attachment portion, said lever portion having a nose end and a handle end, said lever portion overlying at least a section of said attachment portion and including a peripheral reinforcing bead to stiffen the lower portion against bending about a transverse axis; and

means for joining said attachment portion to said panel with the nose end of the tab overlying said ledge and with said tab except for said nose end lying substantially completely within the perimeter of said panel whereby lifting of the handle end of the tab pivots the lever portion about said hinge and forces the nose end against said ledge to thereby exert an outward force on said panel to initiate rupture of said line of weakness to thereby form a pressure equalizing opening, said ledge supporting said nose end of the tab to thereby lock said tab and said container wall against being pulled into the container following formation of the pressure equalizing opening.

2. A combination as defined in claim 1 wherein said means for joining attaches said attachment portion to said panel at two spaced regions of said attachment portions to thereby prevent pivoting of the tab about said means for joining.

3. A combination as defined in claim 1 wherein said nose end of said tab is in the form of a narrow projection of progressively decreasing width as it extends forwardly, said narrow projection allowing said ledge to cover a minimum area of the container.

4. In an easy opening device adapted for vacuum packaging, the combination of:

a substantially fluid-tight container having a pressure therein less than atmospheric, said container having a container wall which is urged inwardly by atmospheric pressure acting on the exterior surface thereof;

a line of weakness in said container wall defining a removable wall segment removable from said container wall to define an opening in said container wall, atmospheric pressure acting on the exterior of the container wall tending to urge the container wall inwardly into the interior of the container;

said container wall having a wall section outside of said removable wall segment and contiguous a section of said line of weakness, said wall section having substantial resistance to complete inward bending;

a tab having a lever portion, said lever portion having a nose end and a lifting end at opposite ends of the lever portions;

attachment means for joining said tab intermediate said ends to said removable wall segment with the nose end of the tab overhanging said wall section and with the lever portion overlying at least a portion of the removable wall segment so that lifting of the lifting end of the tab pivots the lever portion to bring the nose end into forcible engagement with said wall section and to apply an outward lifting force on the removable wall segment to thereby initiate rupture of said line of weakness and form a pressure equalizing opening in the container wall; and

said nose end bearing on said wall section throughout the formation of said opening and said wall section being sufficiently rigid to form a stop for preventing the inward rush of air into the container from drawing the container wall and the tab into the container.

5. A combination as defined in claim 4 wherein said minor portion and said peripheral means defining a tab is integrally constructed of sheet metal and includes an attachment portion which is secured to said removable wall segment by said attachment means and which is integrally joined to said lever portion by a fold portion, said lever portion overlying at least a section of said attachment portion with at least a portion of the sheet metal of the tab between said lever and attachment portions being sufficiently pliable to define a hinge to allow the lever portion to pivot about said hinge relative to said attachment portion.

6. A combination as defined in claim 4 wherein said removable wall segment defines a removable panel which covers a major portion of the area of said container wall.

7. A combination a defined in claim 4 wherein said container includes a container body and said container wall is a circular end wall having circular peripheral means for attaching said end wall to said container body, said line of weakness includes a major arcuate portion concentric with said peripheral means and lying closely adjacent said peripheral means and a minor portion extending between the ends of said major portion and defining with said peripheral means said wall section.

References Cited UNITED STATES PATENTS 2,723,778 11/1955 Rabak 220-48 X 7 3,187,928 6/1965 Bozek 22054 X 3,366,270 1/1968 Khoury 22054 GEORGE T. HALL, Prmiary Examiner.

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