Patent Publication Number: US-4318493-A

Title: Easy opening container

Description:
BACKGROUND OF THE INVENTION 
     This invention pertains to containers which are made of thin sheet metal such as aluminum less than 10 mils thick and which comprise as top dome-like portion which tapers to a small pour opening. Various closures have been made for the opening, most of which are plastic and require that they be inserted into the opening with a tight fit. This requires that the dome section must be constructed in such a way as to resist the axial loads imposed during insertion of the closure or complex support mechanisms must be provided to prevent axial collapse of the top during assembly with the closure. 
     DISCUSSION OF THE PROBLEM 
     Because of the thin section of the metal of the container, it is necessary to provide a closure which can be opened without rupturing the container, but which will sustain the pressure imposed thereon of between 90-140 pounds per square inch. The closure must also be easily fabricated, preferably with existing technology and machinery to minimize capital investment. It must also be unobtrusive and its operation easily perceived. The containers must also be stackable for pallatizing. 
     SOLUTION OF THE PROBLEM 
     This invention provides a closure which may be manufactured with existing equipment and which may be secured to the container preferably by adhesives or crimping to the neck of the container. 
     The invention comprehends forming a closure having a panel with a score which defines a tear section which is openable by a lever tab secured to the panel outside the tear section, the tab having a nose portion overlying the tear section and a handle or lift portion which unobtrusively extends to one side of the closure and is draped over a conical or dome section of the top of the container. 
     The invention comprehends providing a closure made of a thin sheet metal such as aluminum which comprises a top wall and a peripheral skirt portion which fits about an outturned curl at the upper end of the neck portion of the container, the lower edge of the skirt as it is being crimped under the curl, compresses a sealing material interposed between the opposing portions of the closure and curl. 
     One of the objects of the invention is to provide a closure of thin sheet material which will bulge outwardly upon filling of the container with pressurized contents, and employing this bulging to hold the opening tab, secured to the top of the closure, tightly against the top edge of the closure and also alongside the container so that it cannot be snagged and moved to accidentally open the container. 
     A different object is to provide an opening device for the closure in the form of a Z-shaped tab having (1) a top leg overlaying a rupturable top wall of the closure, (2) a vertical leg lying alongside the neck of the container, and (3) a bottom leg overlying a frusto-conical transition portion of the container joining the neck with the cylindrical body of the container. 
     The invention also contemplates providing an opening device or tab for the closure in which the tab has an upper portion riveted to a scored top wall of the closure generally parallel thereto in the unpressured condition of the closure, the upper portion being connected to a vertical part of a handle which lays alongside the neck of the container and at its lateral edge is abuttable with the perimeter of the top wall to prevent the tab from rotating about the rivet out of proper position with respect to the score so that upon lifting of the tab handle the upper portion of the tab will apply pressure against the top wall in a predetermined location which will cause the score to fracture and thus open the container. 
     The invention is applicable to glass or plastic bottles which have a bead about the upper end of the neck and provides an easy opening non-detachable device for any of the foregoing containers. 
    
    
     These and other objects and advantages inherent in and encompassed by the invention will become more apparent in the specification and the drawings wherein: 
     FIG. 1 is a fragmentary perspective view of a container incorporating my novel closure; 
     FIG. 2 is an enlarged fragmentary top plan view thereof; 
     FIG. 3 is a fragmentary cross-sectional view taken substantially on line 3--3 of FIG. 2 showing the precrimped condition of the closure; 
     FIG. 4 is an enlarged cross-sectional view taken substantially on line 4--4 of FIG. 1; 
     FIG. 5 is a cross-sectional view as in FIG. 4 but showing the closure in open position. 
    
    
     DESCRIPTION OF FIGS. 1-5 
     The drawings illustrate a metal container generally designated 2 having a cylindrical body 4 and a bottom (not shown). The top portion 6 is a section of a cone and tapers to a narrow neck 8 which is in the form of a curl having an inner wall portion 9, an upper wall portion 10 and an outer wall portion 11. 
     A closure 15 is applied to the neck after the container is filled with pressurized beverage and comprises a panel 16 having a peripheral skirt 18, a portion 19 of which is precrimped in a section beneath the forward portion 20 of a handle 22 of a tab 25. 
     The tab 25 comprises a forward end nose portion 26, an intermediate securement portion 28 in the form of a lug which at its forward wall is hingedly connected to the rear end of the nose and at its rear and is apertured and mounted onto a rivet 20 which is integral with and formed from the panel 16. The forward portion of the handle is connected by a pair of laterally spaced legs 32, 33 to the rear end of the nose in flanking relation to the lug 28. The rear end of the forward portion 20 of the handle or lift portion of the tab is connected to the upper end of an intermediate vertical portion 35 of the handle and the lower end of portion 35 is connected to the forward end of a rear portion 38 of the handle which projects outwardly of portion 39 in closed position of the closure opposes the top surface 40 of the conical section of the body and extends over a finger-access depression 42 formed in the conical section 6. 
     As best seen in FIG. 3, in the unpressurized condition the top panel of the closure is depressed slightly inwardly and the handle portion is thus elevated above the periphery of the panel. The 4-6 mil aluminum sheet stock from which the end closure is made will balloon out into a convex shape as seen in FIG. 4 when the skirt portion is crimped about the curl and compresses the sealing material 45 such as plastisol or the like between the peripheral portion 46 of the panel and the opposing top wall portion 10 of the curl and between the skirt and the outer wall 11 of the curl. During crimping the peripheral portion 46 as well as the skirt are formed into a U-shaped cross-section as best seen in FIGS. 4 and 5. 
     It will be noted in FIG. 3 that the section 19 is partially precrimped prior to application to the neck of the container so that it will clear the handle portion of the tab and also facilitate application of a crimping tool between the vertical handle portion of the tab and the outside of the section 19. 
     It will be noted that the geometry of the parts is so chosen that the inner or forward portion of the handle upon expension of the panel into an outwardly convex shape, will bear firmly as at 50 (FIG. 4) against the top of the peripheral portion 46 of the closure panel. Thus pallatizing of the cans is accommodated, it being understood that there is a paperboard placed over the top of each level of cans and those above seat on the paperboard on top of the level therebelow. 
     In order to open the container, the handle of the tab is lifted by grasping portion 38. The tab hinges at the connection of the lug 28 with the nose 26. The nose which overlies only a minor portion of the severable panel section 52 defined by score 54 in the end panel presses on section 52 causing the score 54 to rupture and section 52 to depress into the container as seen in FIG. 5. After opening, the tab is returned to the position shown in FIG. 3 by depressing the handle. 
     It will be appreciated that the closure is responsive to the internal pressure in the can to hold the handle in an unobtrusive position where if the tab is struck accidentally, the force will be primarily transmitted to the neck and body of the container and not to the nose of the tab in an opening sequence which requires rotation of the tab. Thus a novel and effective opening device has been provided with the attendant safeguards against accidental opening. 
     A further feature comprises having the other handle portion opposing the top of the cone at a radially outwardly convergent angle. The handle engages the top at 55. This has the effect of providing a shock absorbing buffer in that as the handle is depressed on the top portion 1 the bottom portion will slide on the cone and the vertical portion of the handle will flex.