US 3764038 A
Description (OCR text may contain errors)
United States Patent [1 1 Heffner Oct. 9, 1973 EASY OPENING CONTAINER WALL  Inventor: Robert E. Heffner, Lower Burrell, Hall H V H l V Attorney-David W. Brownlee [73 Assignee: Aluminum Company of America, 1 New Kensington, Pa.  ABSTRACT  Filed, Dec 27 1971 An easy opening container wall is provided including a score line defining a panel which is at least partially  Appl. No.: 212,232 removable from the wall and a tab with a nose end overlying the container wall and affixed to the remov- 2 U. able panel near its Starting end and a handle end E 5' 4 ward the opposite edge of the container wall, and  Fieid 48 27 44 which further includes a tear strip defined by a U- shaped score with its open end toward the starting end  References Cited of the removable panel and its starting end attached to th t b. UNITED STATES PATENTS e a 3,604,589 9/1971 Fraze 220/54 9 Claims, 7 Drawing Figures 3,450,300 6/1969 Saunders... 220/54 3,618,815 11/1971 Heffner..... 220/48 3,404,801 10/1968 Silver 220/54 Patented Get. 9, 1973 2 SheetsSheet 1 FIG. 3.
Patented Oct. 9, 1.973 3,764,038
EASY OPENING CONTAINER WALL BACKGROUND OF THE INVENTION It is known to provide easy Opening container walls with pull tabs which are attached thereto at two locations as disclosed in US. Pat. Nos. 3,618,8l;
3,604,589; 3,477,608 and 3,221,924, among others. In
the container walls disclosed in these patents, one of the attachments is made to a relatively small tear section which is completely severed from the container wall prior to removal of a large panel portion. Such tear sections are usually provided for venting gases or air into or out of a container on which the wall is affixed. There are also a number of disclosures of easy opening container walls which include a primary score around a removable panel portion and a secondary score within the removable panel portion to facilitate rupture of the primary score. Such disclosures are contained in US. Pat. Nos. 3,450,300 and 3,404,801, among others.
SUMMARY OF THE INVENTION This invention provides an easy opening container wall with a pull tab thereon which includes means attached to the handle and of the tab and to the container wall for controlling bending of a removable panel in the container wall during opening to insure initial opening of a relatively large portion of the removable panel with a minimum of effort. In a preferred embodiment of the invention, such bend control means comprises a U- shaped tear strip in a container wall with the open end of the tear strip toward an adjacent edge of the removable panel and the closed end of the tear strip attached to the handle end of a tab.
Accordingly, an object of the invention is to provide an easy opening device which includes means for controlling bending of a removable panel portion during opening.
Another object of the invention is to provide an improved easy opening container wall with means therein for facilitatingseverance of a removable panel from the wall.
BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects and advantages of the invention will be more fully understood and appreciated with reference to the following description and the drawings appended hereto wherein:
FIG. 1 is a top plan view of a container wall of the invention prior to attachment of a tab to the end;
FIG. 2 is a bottom plan view' of a tab for attachment to the container wall of FIG. 1;
FIG. 3 is a top plan view of the container wall of FIG. 1 after attachment of the pull tab of FIG. 2 to the end;
FIG. 4 is a cross-sectional view of a container wall of the invention illustrating initiation of opening;
FIG. 5 is a cross-sectional view similar to FIG. 4 and further illustrating initiation of rupture of the score line around the starting end of the removable panel in the container wall;
FIG. 6 is a cross-sectional view similar to FIGS. 4 and 5 and further illustrating completion of the lifting portion of the opening sequence; and
FIG. 7 is a perspective view of a container wall of the invention illustrating further rupture of the primary score around the removable panel.
DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. I, a sheet metal container and wall 10 for a can or other container is illustrated before a tab is attached to the end. Preferably, can end 10 is made of aluminum or an alloy thereof, although it can also be made of other metals or of plastic. Wall 10 may have peripheral seam 14 therearound for joining it to a container body by conventional methods, and may have a peripheral groove 16 adjacent seam 14 to strengthen the end against reversal or outward doming. A circular line of weakness or score 18 is cut in wall 10 inwardly of and adjacent to groove 16 to define a removable panel 20 for providing acess to the contents of a container on which the wall is seamed. Ends of this type with a score line which permits removal of a major portion of the end wall are generally called full panel pull-out" or full panel removal" type ends. In order to facilitate gripping a tab which will be affixed to wall 10, a depression or finger well 22 may be embossed or otherwise formed in the wall as is conventional. A gap between the end of a tab and container wall 10 in finger well 22 permits a user to insert a finger or finger nail under the end of the tab to lift it.
It is a feature of this invention that container wall 10 includes a second line of weakness or score 26 defining a tear strip 28 which is only partially severable from the container end, and which is attached to a tab to control bending of removable panel 20 as will be described. Some previously known easy opening container walls have included a second score line for facilitating rupture of the primary score, and some previously known easy opening container walls have included two attachments of a tab to the removable panel, but none has included a secondary score in the removable panel defining a partially severable strip which is attached to the tab to control bending of the panel. By providing a tear strip which is only partially severable from removable panel 20, the present invention provides a permanent connection between the removable panel in container wall 10 and the handle end of a tab which controls bending of opening the opening panel along a predetermined line. The location of such a predetermined bend line is generally dependenton the location of the connection of tear strip 28 to container wall 10. This connection of the tear strip 28 to the container wall 10 is defined by the open end of U-shaped score 26. By locating the open end of U-shaped score 26 a substantial distance, approximately 1% inch in container wall 10 selected for illustration, from the score line around the starting end of removable panel 10, a relatively large arc of the removable panel will be opened during initial lifting of the tab. This portion of the removable panel is plunged into a container on which end wall 10 is seamed and helps to reinforce the end against doming or buckling which can make it difficult to further rupture the primary score.
Closure 10 may further include score lines 27 extending outwardly from the open end of U-shaped score 26 along a chordal line through such open end and reversely curved wing-shaped score segments extending from the outer ends of score lines 27 around removable panel 20 adjacent and parallel to score 18. Score lines 27 provide weakening in removable panel 10 to facilitate removal of the panel as will be described. Score segments 29 may extend approximately one-half of the way around end wall 10, although the invention is not limited with respect to the length of such segments. The location of score lines 27 and the length of tear strip 28 are not considered to be critical to the invention. In end wall selected for illustration, tear strip 28 extends from score lines 27 which are located approximately one-eighth of the way across removable panel, to approximately the center of the panel, and is exemplary of an end wall of the invention.
End wall 10 further includes two integral upstanding hollow rivets 30 and 32, one in the starting end of removable panel and one in the starting end of tear strip 28 for attachment of a tab to the wall at these two locations. Rivets 30 and 32 are preferably located on a diametrical line across end wall 10 through the longitudinal axis of tear strip 28. Rivets 30 and 32 may be integrally formed from a sheet metal end wall as is well known in the container and closure art.
Turning to FIG. 2, a tab 40 is illustrated for attachment to a can end 10. Tab 40 may be formed from sheet metal, preferably aluminum or an alloy thereof, and has a triangular shaped nose end 42 and a handle end 44 with a large aperture therein to facilitate gripping by a user. Referring further to FIG. 3 et. seq., tab 40 has a substantially planar upper wall with two downwardly embossed wells 46 and 48 therein and with apertures in the bottom of the wells for receiving integral rivets for attachment of the tab to a container wall. To strengthen tab 40 and avoid sharp edges, the sheet metal of the tab may be curled downwardly and inwardly around the large finger aperture in the handle end of the tab and along the outer edges of the tab to form beads 50 and 52 respectively. Nose end 42 of tab 40 may also be reinforced by means of the downwardly directed flange 54 which may have a point 56 on the end of the tab nose to facilitate rupture of the score line at the starting end of a removable panel in a can end.
FIG. 3 illustrates a tab 40 attached to a container end 10 by means of integral rivets 30 and 32. As attached, nose end 42 of tab 40 overlies the opening end of panel 20, and handle end 44' of the tab overlies tear strip 28 toward the opposite side of the container end. The outer end of handle end 44 is disposed over finger well 38 in container end 10 so that a user can more easily grip the handle end of the tab.
FIGS. 4-7 illustrate opening of a container on which end wall 10 is seamed by lifting tab 40 and pulling it to rupture score lines 18 and 26 in the wall. It is seen in FIG. 4 that initial lifting of handle end 44 of tab 40 exerts an upward force on rivet 32 to rupture score line 26 around tear strip 28 to partially sever the tear strip from the end. This forms a vent in container wall 10 to permit pressurized gases to escape from the can, or air to enter the can, and also facilitates further lifting of tab 40 to initiate rupture of score 18 as will be described. Since the vent is located under tab 40, the vent opening is shielded by the tab and accidental spraying of the contents of the can on the user during opening is substantially prevented.
Rupture of score line 26 around tear strip 28 permits a substantial length of tab 40 to be raised slightly above the surface of end wall 10 as illustrated in FIG. 4, and facilitates application of force against the starting end of removable panel 20 by the nose of the tab. This force initiates rupture of score line 18 as illustrated in FIG. 5. Lifting of tab 40 may also be facilitated by upward doming or flexing of end wall 10 as illustrated. If tab 40 could not be lifted off the surface of end wall it to facilitate gripping its handle end, initiation of rupture of score 18 could be difficult. In some prior end wall structures such as those illustrated in US. Pat. No. 3,618,815, the rivet connection between the tab and the removable panel is located a substantial distance from the starting end of the removable panel in order to open a relatively large area in the end wall, and this makes it difficult to lift the tab to initiate rupture of the score line around the removable panel. In others, the connection is located relatively close to the score line around the removable panel, but these ends include no means for initially plunging a relatively large portion of the panel into a container as is desired for some purposes. The present invention provides an end wall with a tab thereon which can be initially lifted to facilitate gripping to rupture the score line around the starting end of a removable panel and also plunges a relatively large portion of the removable panel into a can as will be described.
As illustrated in FIG. 4, end wall 10 of the invention is unique in that tear strip 28 in removable panel 20 remains attached to container wall 10 as the removable panel is plunged into a can. Tear strip 28 thereby provides a connection between handle end 44 of the tab 40 and container end 10 and forces bending of the opening flap to occur along a predetermined line. Tab 40 is substantially rigid and is attached to both tear strip 28 and removable panel 20 so that the connection of the tear strip to the container wall controls pivoting of the tab after the tear strip has been partially severed from the end wall. Continued lifting of tab 40 therefore hinges about the chordal line on which score lines 27 are located to plunge a relatively large flap of panel 20 into container 62 as illustrated in FIG. 6. It is believed that initially opening a relatively large are or flap such as this upon lifting of tab 40 facilitates removal of panel 20 because it prevents doming or buckling of the panel when tab 40 is pulled upward to rupture score 18 around a periphery of the removable panel. If only a short arc of score 18 were ruptured when tab 40 is lifted to a vertical position, the flap of metal from panel 20 which is turned downwardly into a container is not of sufficient strength to prevent doming or buckling of the panel when the tab is pulled outwardly to sever the remaining length of the score. When a panel domes during such removal, the score around the periphery of the panel is placed in tension rather than in shear, and it is much more difficult to rupture the score in tension thanin shear. Accordingly, buckling or doming of the removable panel can make it difficult to effect rupture of the score around the panel and removal of the panel. End wall 10 solves this problem by rupturing a relatively long are of score 18 and bending a relatively large flap of metal into a can to prevent any doming when the tab is pulled to effect complete removal of the panel.
It is another feature of end wall 10 that score segments 29 extend around approximately one-half of panel 20 to facilitate rupture of score 18 during removal of the panel. When tab 40 is pulled upwardly as illustrated in FIG. 7, score 26 ruptures along its entire length, including lines 27 and segments 29, as score 18 is being ruptured. This results in the application of the removal force closely adjacent score 18 to ensure that the residual metal in such score is placed in shear rather than in tension. The pulling force which is applied to tab 40 is transmitted to removal panel 20 through the strips of metal between scores 29 and 18 on either side of the removal panel. Since these strips of metal are contiguous score 18, the force which is applied through such strips will also be applied contiguous score 18 rather than being applied more centrally in the removable panel. The ends of score 29 could extend further around removable panel 20, but it is believed that approximately half way is an optimum length. Beyond that point, score 18 is again coverging and there is less tendency of removal panel 20 to dome. lf scores 29 were terminated short of the half way point, doming of the removable panel 20 could be excessive and result in difficulty in rupturing score 18.
It is therefore seen that an easy opening container wall is provided in which initiation of rupture of the score line is facilitated by increasing the mechanical advantage of the tab, but in which a relatively large arc of the primary score is ruptured around the removable panel to reinforce the removable panel against upward doming or buckling during removal of the panel. Although a particular embodiment of the invention has been illustrated and described, it will be apparent to those skilled in the art that numerous variations can be made in the details of such embodiments without departing from the invention.
What is claimed is:
1. An easy opening container wall having a substantially circular line of weakening therein defining a removable panel having a starting end adjacent the periphery of the wall and a partially removable tear strip in said removable panel with a starting end toward the center of the container wall and a terminal unscored end toward the starting end of said removable panel, said container wall further having a tab attached to said removable panel and to said tear strip in their starting ends whereby said tear strip remains attached to said tab and said removable panel during opening to control bending of said removable panel.
2. An easy opening device as set forth in claim 1 in which said tab is made of sheet metal and has reinforced portions along its longitudinal edges to make it substantially rigid.
3. An easy opening device as set forth in claim 2 in which said tab has downwardly curled edge portions.
4. An easy opening device as set forth in claim 3 in which said tab has downwardly formed wells therein and apertures in the bottoms of the wells through which the tab is attached to the container wall.
5. An easy opening container wall as set forth in claim 1 in which said tear strip is defined by a Ushaped score.
6. An easy opening container wall as set forth in claim 5 in which said U-shaped score has outwardly extending segments on its open end. located on a chordal line in said removable panel.
7. An easy opening container wall as set forth in claim 5 in which said U-shaped score has curved segments on its open end extending parallel and adjacent to said circular score along portions thereof on either side of the starting end of the removable panel.
8. An easy opening container wall as set forth in claim 1 in which a depressed well is provided in thewall under the handle end of the tab.
9. In an easy opening device in a container wall comprising a circular line of weakness in the container wall defining a panel which is at least partially removable from the container wall and having a starting end adjacent the periphery of the container wall and a tab attached to the starting end of the panel, the improvement comprising a second line of weakness in the container wall within said removable panel defining a tear strip having a starting end toward the center of the container wall and a terminal unscored end toward the starting end of said removable panel, and said tab is attached to said tear strip near its starting end, whereby said tear strip remains attached to the container wall during opening to control bending of said removable panel.