Easy Opening Container Wall With Vent Opening

Abstract

An easy opening container wall including a container wall having a line of weakness therein defining a tear portion. The container wall has a rupturable region other than the line of weakness. A tab is attached to the container wall and is movable sequentially through at least first and second movements. A vent opening is formed in the container wall in response to the first movement, and the line of weakness is ruptured in response to the second movement.

Description

BACKGROUND OF THE INVENTION

Containers for certain products contain positive or negative pressure and when such containers are provided with easy opening container walls, it is desirable to vent the container to atmosphere prior to initiation of severance of the main score line which defines the removable tear portion. As used herein the term "vent" has reference to the creation of an opening in the container wall through which fluid can flow to cause the pressure within the container to be substantially atmospheric. Thus, venting occurs whether the interior of the container is initially above or below atmospheric pressure.

Prior art easy opening container walls which embody a venting principle involve forming the vent opening as a result of the initial lifting of the tab. Continued lifting of the tab in the same general direction results in rupture of the main score line. Typically this is the result of rapid and unidirectional pivotal movement of the tab so that the vent opening and the rupture of the score line occur in rapid sequence.

A problem with these easy opening container walls is that insufficient time between the formation of the vent opening and the rupturing of the main score line is provided to fully vent the container especially when the initial pressure within the container differs substantially from atmospheric. Accordingly, there is a pressure differential across the removable tear portion at the instant that the severance of the sheet material along the main score line is initiated. This pressure differential may be sufficient to rapidly completely sever the tear portion from the container wall with consequent danger to, or frightening of, the user. Another problem is that the rapid movement of gas through the vent opening may cause some of the product to be sprayed through the vent opening. An ever present problem in the easy opening container field is achieving initial rupture of the line of weakness with a minimum amount of effort on the part of the user.

SUMMARY OF THE INVENTION

The present invention eliminates these disadvantages of prior art constructions by utilizing a tab which requires at least first and second sequential manipulative movements to rupture the line of weakness. The vent opening is formed in the container wall in response to the first movement and the line of weakness is ruptured in response to the second movement. With this arrangement, the vent opening is formed well in advance of the initiation of severance of the line of weakness so that there is sufficient time to adequately vent the container before the line of weakness is ruptured.

Preferably the manipulative movements of the tab are in different directions and the vent opening is preferably formed prior to the last of such manipulative movements. The time required to change the direction of movement of the tab and the time to accomplish the last manipulative movement affords the necessary time for adequate venting.

These results can best be accomplished by using a tab which includes a lever portion and a gripping portion interconnected by a pliable connecting portion. The lever portion is connected to the tear portion and the gripping portion is initially substantially flat against the container wall. To operate the tab, the user moves the outer end, i.e., the end remote from the connecting portion, of the gripping portion away from the container wall. This movement is accomplished relatively easily as the connecting portion is readily bendable. When the gripping portion has been raised to the desired angle, the user then exerts an outward pulling force to cause the lever portion to initiate severance of the line of weakness. An advantage of this tab is that the line of weakness is easily severed.

With the tab just described, the first movement consists of pivoting of the gripping portion relative to the lever portion to the desired angle and the second movement is the outward pulling of the gripping element resulting in pivoting of the lever portion. The pivotal movements of the lever portion and the gripping element are in opposite directions.

To provide a vent opening, the container wall has a weakened region other than the line of weakness. The weakened region is connected to the tab and ruptures in response to the first movement of the tab. In a preferred form of the invention, the weakened region is connected to the tab by a rupturable vent rivet formed integrally with the container wall. It can be seen that this combination provides a vent opening and sufficient venting time without sacrificing ease of opening.

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 constructed in accordance with the teachings of this invention.

FIG. 2 is an enlarged fragmentary sectional view taken along line 2--2 of FIG. 1.

FIG. 3 is an enlarged fragmentary sectional view taken alone line 3--3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings and in particular to FIG. 1 thereof, reference numeral 11 designates an easy opening container wall constructed in accordance with the teachings of this invention. The easy opening container wall 11 includes a can end 13 of sheet aluminum or other suitable sheet material having a peripheral attachment flange 15 for attaching the container wall 13 to a can body (not shown). A line of weakness in the form of a score line 19 in the container wall 13 defines an elongated tear portion 21 which is removable from the container wall. A tab 23 is attached to the leading end of the tear portion 21 by suitable means such as a hollow rivet 25 formed integrally with the leading end of the tear portion.

The tab 23 in the embodiment illustrated is integrally constructed from a single piece of sheet aluminum and includes a lever portion 27 and a ringlike handle portion or gripping element 29 integrally joined by a pliable connecting portion 31. The lever portion 27 has a lifting end or region adjacent the connecting portion 31 and a fulcrum end 35. The rivet 25 projects through an aperture 37 (FIG. 2) in the lever portion 27 adjacent the fulcrum 35 to attach the tab 23 to the leading end of the tear portion 21. As best shown in FIGS. 2 and 3 the tab lies flat against the container wall 13.

The lever portion 27 is stiffened longitudinally by integral, longitudinal reinforcing beads 40 and 41 which are formed by curling marginal portions of the lever portion downwardly and inwardly. The fulcrum end 35 is defined by an upwardly extending flange 42. The distance between the connecting portion 31 and the rivet 25 is many times greater then the distance between the rivet 25 and the fulcrum end 35. This provides the lever portion 27 with substantial mechanical advantage in initiating severance of the score line 19.

The handle portion 29 lies in substantially the same plane as the lever portion 27 and completely surrounds the latter. The handle portion 29 has a handle end or lifting end 47, a bearing region or end 49 and a large finger receiving opening 51. A marginal portion of the handle portion 29 is turned upwardly and inwardly to define an outer reinforcing bead 53 which extends substantially completely around the handle portion 29. The sheet material surrounding the opening 51 is turned upwardly and outwardly to define an inner reinforcing bead 55 which extends for a substantial distance around the opening 51.

In the embodiment illustrated, the handle portion 29 also serves as a lever and is hinged to the lever portion 27 by the connecting portion 31. The connecting portion 31 lies closely adjacent the bearing end 49 and is quite remote from the lifting end 47 so that the handle portion 29 has substantial mechanical advantage.

In the embodiment illustrated, the lever portion 27 is constructed from the sheet material which would otherwise be scrapped as a result of the formation of the opening 51. The lever portion 27 extends diametrically for considerably more than one half of the diameter of the opening 51.

As shown in FIG. 1, the bead 53 terminates in bead ends 57 and 59. The bead ends 57 and 59 are in closely adjacent generally confronting relationship at the end of the tab opposite the handle end 47. An aperture 61 is formed in the gripping element 29 intermediate the end faces 57 and 59. The aperture 61 receives a small diameter, rupturable, vent rivet 63 which is formed integrally with the container wall 13 and which forms a weakened region thereof. The vent rivet 63 may be of the type disclosed in copending application, Ser. No. 777,584.

By interrupting the outer bead 53, the vent rivet 63 can be placed closer to the end 49 of the tab 23. This increases the mechanical advantage of the gripping element 29 insofar as rupturing of the vent rivet 63 is concerned. Furthermore, by interrupting the outer bead 53 as shown, heading of the hollow rivet 63 is facilitated.

In operation of the tab 23, the lifting end 47 is moved away from the container wall to pivot the gripping element 29 relative to the lever portion 27 as permitted by the pliable connecting portion 31. The pivoting of the gripping portion 29 is clockwise as viewed in FIG. 2 and results in an upward lifting force being applied to the vent rivet 63 by the gripping segment 29. Upon continued pivotal movement of the gripping segment 29, the upward lifting force applied to the vent rivet 63 becomes efficient to rupture the latter to thereby provide a vent opening in the container wall. Next, the user directs an outward pulling force on the gripping portion 29. This elevates the end of the lever portion 27 remote from the fulcrum 35 to pivot the lever portion counterclockwise (as viewed in FIG. 2) about the fulcrum 35 to cause rupture of the line of weakness 19 by the lever action of the lever portion. Continued outward pulling on the gripping portion 29 results in complete removal of the tear portion 21.

By having the outer bead 53 extend into close relationship with the vent rivet 63, the gripping portion 29 is provided with sufficient rigidity to apply adequate force to the rivet 63 to rupture the latter. With the present invention, the vent opening is formed in response to generally pivotal movement of the gripping portion 29 and initiation of severance occurs in response to an outward pulling force on the gripping portion which in turn results in opposite pivotal movement of the lever portion. As these movements occur in different directions and sequentially, the normal operation of the tab 23 inherently provides sufficient venting time to thereby assure that the pressure within the container will be substantially atmospheric.

Although a specific embodiment of the invention has 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.

Claims

I claim:

1. An easy opening container wall comprising:

a container wall having a line of weakness therein defining a tear portion at least partially removable from the container wall to form an opening therein;

a tab having a lever portion and a ringlike gripping segment, said gripping segment terminating at one end in a handle end and at the opposite end in a bearing region, said lever portion being joined to the gripping segment at a location adjacent said bearing region and projecting generally radially of the gripping segment generally toward the handle end, said lever portion being substantially longitudinally rigid;

means for attaching the lever portion to the container wall so that the lever portion can initiate severance of the line of weakness, said location being spaced from said attaching means;

said container wall having a weakened region therein other than said line of weakness; and

means other than said attaching means for interconnecting a region on said tab adjacent said location with said weakened region, movement of the handle end away from the container wall forcing the bearing region against the container wall and severing the weakened region and subsequent outward pulling of said gripping element initiating severance of the container wall along the line of weakness.

2. An easy opening container wall as defined in claim 1 wherein said weakened region includes a rupturable vent rivet formed integrally with the container wall.

3. An easy opening container wall comprising:

a container wall having a line of weakness therein defining a tear portion at least partially removable from the container wall to form an opening therein;

a tab having a lever portion and a ringlike handle portion joined to the lever portion by a pliable connecting portion, said lever portion being substantially longitudinally rigid;

means for attaching the lever portion to the container wall so that the lever portion can initiate severance of the tear portion;

said handle portion being joined to said lever portion at a location spaced from said attaching means, said handle portion extending from said location generally in the direction of said attaching means and terminating in a lifting end remote from said location, said handle portion having a first movement in which the handle end is moved away from the container wall to pivot the handle portion relative to the lever portion generally about said connecting portion and a second movement subsequent to said first movement in which the handle portion is pulled outwardly to move said lever portion to cause the latter to initiate severance of the line of weakness; and

means on said container wall responsive to said first movement of said handle end to form a vent opening in said container wall whereby said vent opening is formed for a sufficient time prior to the rupture of the line of weakness to permit adequate venting to occur prior to the rupture of the line of weakness.

4. An easy opening container wall as defined in claim 3 wherein said last mentioned means includes a weakened region in said container wall and means for connecting said weakened region to said tab adjacent said connecting portion.

5. An easy opening container wall comprising:

a container wall having a line of weakness therein defining a tear portion at least partially removable from the container wall to form an opening therein;

said container wall having a weakened region therein spaced from said tear portion;

a tab constructed of a single piece of sheet material, said tab including a lever portion and a ringlike handle portion joined to the lever portion by a pliable connecting portion, said lever portion being substantially longitudinally rigid;

means for attaching the lever portion to the tear portion;

said handle portion having a handle end, said lever portion projecting from said connecting portion generally in the direction of said handle end; and

means for connecting said tab adjacent said connecting portion to said weakened region.

6. An easy opening container wall as defined in claim 5 wherein said handle portion comprises outer and inner reinforcing beads, both of said beads substantially circumscribing at least a substantial segment of said lever portion.

7. An easy opening container wall as defined in claim 6 wherein said outer bead terminates in two confronting spaced bead ends and said last mentioned means includes a rivet formed integrally with the container wall and projecting through said tab substantially between said bead ends.

8. An easy opening container wall as defined in claim 1 wherein said tab is integrally constructed of sheet material and a marginal portion of the sheet material of said gripping segment is turned upwardly to define a reinforcing bead, said bead terminating in a pair of spaced bead ends adjacent said location, said means for interconnecting including a rivet projecting through said tab at a location closely adjacent said bead ends.