Patent Grant
10661952
“Stay on Tab” (SOT) closures for cans are a ubiquitous form of easy opening packaging for pressurized beverage containers. With SOT closure systems, as described, for example, in U.S. Pat. No. 3,731,836, a scored line in the metal container end panel is used to create a weakened boundary to which leverage can be applied via a rivet-retained tab to push an opening area through the end panel. Both the tab and the opened flap remain affixed to the end panel after opening.
Numerous patented improvements have been made to the components of the SOT closure over decades of commercial use to improve its functionality, reliability, and cost. Yet, one of the inherent limitations of the SOT solution is that it does not lend itself to reclosing since the score line break deforms the freed panel in a way that is not readily reversed. Reclosing provides added convenience to consumers of reduced spillage or reduced contamination of contents after the container has been opened.
Improved closures that provide for reversibly reclosing of a sealed container are known in the art. For example, issued U.S. Pat. No. 9,517,866 which shares at least one inventor in common with the present application, describes forms of an easy opening closure suitable for use in metal beverage containers and other forms of sealed packaging with technology related to the present invention, which provides a facile opening mechanism, as well as means for reclosing the package.
Various embodiments of the present invention pertain to a closure for a container, wherein the container has a substantially planar end panel with an aperture therethrough. Within the perimeter of the end panel is a separate and movable interior panel with an extended edge or flange area that covers the aperture and overlaps the boundary around it, the interior panel being initially fixed in place, sealed, and bonded to the end panel, and a moveable tool used to facilitate easy opening and progressive debonding of the interior panel from the end panel, thereby rendering it moveable in relation to the end panel. In certain embodiments, the interior panel may also reclose and either partially or entirely seal the aperture.
Various embodiments of the present invention pertain to aluminum easy-opening end closures that may also be reclosed, and that are suitable for joining to a beverage can in conventional double seaming operations. The interior panel, alternatively referred to as the shutter herein may be bonded around its perimeter to the end panel by heat-sealing, and the moveable tool may be in the form of a rotatable lever interposed between them. To open the closure, a user applies force to the rotating lever to move it axially around an attachment point to progressively debond a substantial portion of the bond perimeter, and then bring it into latched engagement with the shutter.
Various embodiments of the present invention are further directed to improved methods and systems for: more efficient mechanisms for debonding of the shutter, from the end panel; more robust structures for latching of the shutter to the rotatable lever; venting systems that provide for smoother pouring characteristics, and other enhancements to the overall user experience of the closure. The configuration and use of the presently preferred embodiments are discussed in detail below.
The foregoing has outlined rather broadly certain aspects of the present invention in order that the detailed description of the invention that follows may better be understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. Accordingly, the specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention.
As will be understood by those skilled in the art, appropriate design parameters, materials selections, and methods must be used to assure the precise and reliable operation of the closure system in the context of a particular application. While many of the example embodiments herein describe the closure in the context of a beverage can application, the innovation can be adopted to other package forms, for which alternative material selections and assembly methods may be more appropriate.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
A rotatable lever 102 is interposed between the end panel 101 and shutter 103. At its interior hub end, the lever 102 has a small through hole 105C. A formed flexible prong or pawl 107 projects radially from the side of the lever hub. The outer end of the lever 102 incorporates a formed handle 159 contoured to facilitate user grip for actuation. There is a slotted gap 155 between the lever handle 159 and the working edge 161 at the back of the lever. In the assembled closure, the circumferential edge of the end panel aperture 199 inserts into this slotted gap 155 to prevent out of plane movement of the lever end when force is applied and the lever handle 159 is rotating.
The shutter 103 is larger in area than the aperture 199. It incorporates a rivet preform structure 105A in the form of a hollow closed end cylinder that projects towards the lever 102 and end panel 101. During assembly of the closure, the columnar rivet preform structure 105A is passed through coaxial holes 105B and 105C and then collapsed down to a sealed rivet head so as to fasten the three component parts together, with its shank providing an axis of rotation for movement of the lever 102 and shutter 103.
The shutter 103 has a dished central region 126 that accommodates the lever placement and movement, and a planar flanged edge 122 around its full perimeter. The dished central region 126 is deepest near the edge rest positions at each end of the lever's travels with an intermediate tapered ramp contour 124 that provides a working fulcrum for a wedging action of the lever to debond the seal when the assembled closure is initially opened. Notches 131, 132 and 133 formed into the sidewall of the dished central region 126 generally perpendicular to its plane provide notched facets that engage with the latching pawl 107 of the lever 102. Each notch position corresponds to a specific phase of functional engagement between the lever 102 and the shutter 103 as will be further described.
The flat upper surface of the perimeter shutter flange 122 allows uniform close contact with the lower surface 112 of the end panel 101. In some embodiments, the entire upper surface 114 of the shutter 103, including the flanged region 122 is pre-coated with an adherent thin layer of a suitable thermoplastic polymer that is compatible for thermal fusing to the thermoplastic coating on the lower surface 112 of the end panel 101. Taken together these features enable the shutter 103 and end panel 101 to be dry assembled and then readily bonded and sealed together via heat-sealing, an established and scalable manufacturing process involving the controlled application of heat and pressure. The fused adherent surface coating material between the shutter 103 and end panel 101 creates a hermetic seal throughout the dished region 126 that fully surrounds the pour aperture 199 and closure mechanism as shown in
Top views of the closure system assembled from the components of
In the present embodiment, a user initiates opening of the closure by pushing the lever handle 159 to the right to cause counterclockwise (CCW) rotation of the lever arm 177 onto and then up along the ramp contour 124. As it is so rotated, the underside of the lever arm 177 applies an increasing downward force against the surface of the ramp contour 124, since both ends of the lever 102 are effectively constrained against the underside of the end panel 101 by the rivet 195 at the interior hub end and by the working edge 161 at the back end of the lever 102.
Progressively moving the rotating tab lever from the first aperture edge 140 toward the second aperture edge 141 thereby creates a separating force to progressively cleave and debond localized regions of the joint between the end panel 101 and the cover panel 103 along the bond perimeter 160. The ramp provides mechanical advantage to reduce the force required throughout debonding to a manageably low level which for a typical user should be below 5 to 10 lbs.
As the lever 102 is rotated through the opening sequence, the flexing pawl 107 mechanically engages with notches 131, 132, 133 in the shutter 103 in a way that permits motion in only one direction. Thus, after a small partial rotation that moves the pawl 107 from its initial notch position 131 to intermediate notch position 132, the movement cannot be reversed and may serve as a visual indicator for tamper evidencing. The pawl 107 extends radially from the side of the lever hub furthest from the aperture 199. This placement allows for reduced radial dimension, a more compact seal, and greater open pour area on the on the aperture 199 side, and also allows the end panel 101 to effectively shroud the latching mechanism from user interference and environmental contamination.
Through continued applied force, the user moves the rotating lever 102 until it abuts against the opposite second edge 141 of the aperture 199 as shown in
For the shutter 103 to move freely in conjunction with the lever 102, the seal perimeter 160 must be fully disrupted. While in the forgoing description of the present embodiment the lever action was not 100% efficient in achieving such debonding, it is nevertheless possible for a user to complete the full disruption of the seal by moving the lever 102 back to the first aperture edge 140, provided that the components and the latching mechanism are sufficiently robust to effectively shear all of the remaining unbonded area of the seal.
Generally, the force per unit area required to effect shearing of a bonded joint is higher than for cleaving of the bond, and may exceed the preferred force ranges. Thus, in preferred closure embodiments, the debonding efficiency of the lever 102 in moving from the first aperture edge 140 to the second aperture edge 141 will be 60% or more, so that the bond area remaining to be sheared is low and can readily be overcome by a user.
Analysis such as that shown in
Alternative closure embodiments described below provide greater effectiveness debonding in the bracketed segment regions 1 around the rivet 195 than the first example embodiment just described, as well as in bracketed segment region 2 along the first aperture edge 140.
Improved efficacy is achieved in novel embodiments described herein by incorporating different forms of mechanical features on one or more of the components: lever, shutter, end panel, that interact with corresponding mechanical features on the other components to produce functional effects when the lever is rotated. The features are selected to offer mechanical advantage to a user applied force with designs refined to optimize dimensions. Two types of functional mechanism are defined as:
A “debonding mechanism” is a formed mechanical feature on the lever 102 that by design intent will produce a mechanical interaction with the end panel or the shutter as the lever is rotated, with the resultant effect of producing a localized stress in certain specific segments of the bond perimeter between the end panel 101 and the shutter 103, so as to effectuate debonding of that segment; and
a “latching mechanism” is a formed mechanical feature on the lever 102 that by design intent will create a localized fastening engagement between itself and certain corresponding features on the shutter 103 as the lever 102 is rotated. This engagement may be transitional providing for phased, uni-directional movement of the lever 102 relative to the shutter 103, or more permanent as in affixing the two components at the end of the rotational sweep.
For full disruption of the complete bond perimeter, particular embodiments may incorporate a combination of debonding mechanisms involving various stress modes applied to different bond segments, for example at different stages of the opening process and different points of the shutter/end bond perimeter, the applied stress mode may be: cleaving, peeling, tension, or shearing.
Similarly, a combination of latching mechanisms may be used to provide strong, robust, and reliable latching of the shutter to the rotatable lever at various stages of debonding. The latching system should be sufficiently robust to shear any segments of bonded seal remaining when the lever sweep is complete, while binding the shutter and lever together to reversibly close and open the aperture.
Since the rivet 195 functions as both a joint and the axis of rotation for the lever 102 and shutter 103, more effective debonding of the seal in this critical area can improve the overall debonding efficiency as well as operation of the closure. In the previously described embodiment of the present invention, the end panel 101, shutter 103, and lever 102 had a generally parallel and planar aspect in proximity to the rivet 195. Relative rotation of parallel planes does not create separating forces, whereas adding mechanical features on the lever 102 head, shutter 103, or end panel 101 in the area of the rivet 195 that produce mechanical interferences when the lever 102 is rotated can have such beneficial effect.
There are again three major components: end panel 101, lever 102, and shutter 103. In some embodiments, the lower surface of the end panel 101 and the upper surface of the shutter 103 may similarly both pre-coated with an adherent thin layer of a suitable thermoplastic polymer which enables heat-sealing assembly of the closure. As before the shutter 103 incorporates an intermediate tapered ramp contour 124 that the lever acts against to effect debonding at the outer circumference and second aperture edge 141.
The rotatable lever 102 interposed between the end panel 101 and shutter 103 now has at its interior hub end a formed flexible prong or pawl 207 which, in this embodiment, projects down into the plane of the shutter 103 rather than radially. Corresponding stepped notching features 231, 232, and 233 for engagement with the latching pawl 207 are now formed into the shutter base, rather than the sidewall of the dished shutter.
Top views of the closure system in various stages of opening are shown in
To increase debonding efficiency in the vicinity of the lever hub, a small rigid lever hub protrusion 288 has been formed into the lever 102 such that it projects vertically up out of the plane toward the end panel 101 in the assembled closure, which direction shall be referred to herein as the positive Z direction.
However, both are separately visible in
With continued CCW rotation of the lever 102 to the second aperture edge 141 as shown in
As shown in
At points in the progression of the lever rotation where the lever hub cam is not recessed, it presses against the end panel 101 creating a localized mechanical debonding stress in the seal area around the rivet. While a single cam feature is shown, multiple cams distributed around the lever hub may be used to provide more balanced force distribution and to increase the swept bond perimeter for a given degree of rotational travel of the lever.
Top views of the
In all of the foregoing example embodiments described herein, the initial position of the lever 102 was against a left-most first aperture edge 140 when the closure is viewed from above, and the debonding action of the lever 102 is achieved by counterclockwise rotation of the lever 102 toward the right-most second edge. However, the oppositely directed orientation can be equally effective. All of the subsequent embodiments described herein, have the initial position of the lever 102 against a now right-most first aperture edge 140 when the closure is viewed from above and the debonding action of the lever 102 achieved via clockwise rotation.
Top views of the relative positions of the lever 102 and shutter 103 of the present embodiment closure system in various stages of opening are shown in
Downward projecting cam 184 and ribbed structure 187 are both in recessed positions in
Closure embodiments that were described previously incorporated contoured ramp features formed into the surface of the shutter 103 against which a rotating lever arm acted to create a perpendicular separating force in the zone 3 circumferential bond perimeter joining the end panel 101 to the shutter 103. Continued rotation of the lever 102 thereby progressively debonded the seal between the two components in this region. In certain embodiments the seal in the area around the rivet 195 was simultaneously debonded by cams or formed protrusions on the lever hub.
Embodiments described below provide a debonding mechanism with an alternative mode of interaction between the lever 102 and the shutter 103/end panel 101 interface to create separating forces for debonding. Rather than a contoured ramp on the shutter 103, novel formed feature sets incorporated into the shutter 103 as well as the lever 102 simultaneously provide both debonding and latching mechanisms.
A “latching wedge,” defined herein as a mechanical feature that can be formed onto various points on the lever, has at its leading edge (with respect to the forward direction of rotation of the lever), a narrow cross section tapered or curved form that readily enters into and moves along a gap with low resistance. The cross section of the latching wedge increases in scale from its leading edge to its trailing edge, thereby creating a wedging action in the gap. Its trailing edge has a sharply angled or barbed projection that will engender strong mechanical resistance to back rotation of the lever.
When the lever 102 has completed its clockwise rotation to the second aperture edge, as shown in
The entire upper surface 114 of the shutter 103, including the flanged region 122 is pre-coated with an adherent thin layer of a suitable thermoplastic polymer that is compatible for heat sealing to the thermoplastic coating on the interior surface 112 of the end panel. The lower surface 122 of the shutter 103 may have a barrier coating applied to it.
As shown in
The shutter of this current example embodiment provides recessed pockets for all shown latching wedge features on the lever at both their initial assembled rest position as well as at the end-of-travel, latched final position. When the lever has been rotated to the second aperture edge and its debonding action is complete, these end position pockets allow the latching wedges to effectively be retracted, relieving the separating force between the shutter and end panel and allowing the gap between them to reclose. Additionally, sharply inclined back walls in each end position pocket then abut the barbed trailing edge of each latching wedge. These mechanical engagements prevent reversal of rotation and provide secure, multi-point latching of the lever to the shutter.
The angular positions of the latching wedges and pockets are arranged so that the forwardmost wedge feature ends up in a previously unoccupied pocket and the trailingmost wedge feature ends up in the pocket initially occupied by the forwardmost wedge. Distributing multiple wedges around the lever hub provides for a more balanced force distribution and more complete sweeping of the bond area around the rivet for a given degree of rotational travel of the lever. A graduated, ratcheting arrangement of wedges and pockets around the rivet can be realized by increasing the number of wedges and pockets while reducing their radial width.
As a user moves the rotating lever 202 from the
In all views of the assembled closure in
An alternative form of lever that may be implemented into the
Referring back to the
Filled metal beverage containers when sealed typically accommodate some positive internal pressure during storage, the level depending on the application. The first stage of opening a SOT closure on a filled container involves relieving any internal pressure, after which the force needed to extend the opening is reduced. For some embodiments of the current invention, the initial pressure release occurs at the location where the seal is first selectively breached by the lever's action and pressure can escape through a gap created between the shutter and end panel.
When drinking from beverage cans, consumers generally prefer that the container delivers smooth pouring at high flowrate. For the open container, another form of pressure differential bears on this characteristic of the container closure. Pouring from a beverage container aperture may be negatively impacted by limited pathways for air to enter the container and equalize reduced internal pressure in interior headspace caused by beverage outflow. Fluid surface tension blocking the aperture, combined with reduced pressure in interior headspace, inhibits steady flow of liquid resulting in a gurgling, pulsing flow.
The engineering design of the closure on a metal beverage container effects its capability to equilibrate pressure in the internal headspace of the container with the outside ambient. For conventional SOT closures, design solutions for headspace pressure equilibration include providing the largest practicable aperture size or adding supplementary scoreline vent openings in the end panel.
Various embodiments of the present invention include a novel means for creating a pressure equilibration venting channel, defined as a gap created and maintained between the opened shutter and the end panel that provides a continuous air pathway connecting external ambient pressure to interior headspaces above the fluid contents in the container for pressure equilibration of interior headspaces remote from the aperture. Various arrangements of mechanical features on the end panel, shutter, or lever may be used to create and maintain the gap between the end panel and the shutter as the latter is rotated into the open position to create the pouring aperture and simultaneously create the pressure equilibration venting channel between the outer ambient air and interior headspaces.
The wedging ramp 555 is positioned so that, as the shutter is rotated back to open the aperture, it is lifted to create and maintain a gap 560 between the end panel 101 and the shutter as shown in
A small wedging ramp 555 with a maximum height on the order of, for example, 0.060″ is sufficient to pry and hold open both back and front edges of the shutter 103. The wedging ramp 555 does not interfere with debonding or latching systems; in production, this structure could be created as an embossed feature in the end panel 101.
Many alternative combinations of mechanical formations in or on the lever, shutter, and end panel may be used to provide a pressure equilibration venting channel between the opened shutter 103 and the end panel 101. For example, rather than a ramp feature to create separation, channel features might be embossed into the surfaces of the shutter 103 or end panel 101 in areas that overlap when the shutter 103 is opened.
Equilibration can thus be accomplished with a single aperture in the end panel 101 rather than a plurality of openings and separately provided vents. As the shutter 103 is rotated back off the ramp to close the aperture, the gap 560 and thus the pressure equilibration venting channel 565 is eliminated concurrently for more complete reclosing.
Embodiments of the present invention provide superior means for pressure equilibration between remote interior headspace and external ambient air, enabling smooth pouring and high flow velocity per unit aperture area and time even with smaller aperture opening size.
While the present system and method has been disclosed according to the preferred embodiment of the invention, those of ordinary skill in the art will understand that other embodiments have also been enabled. Even though the foregoing discussion has focused on particular embodiments, it is understood that other configurations are contemplated. In particular, even though the expressions “in one embodiment” or “in another embodiment” are used herein, these phrases are meant to generally reference embodiment possibilities and are not intended to limit the invention to those particular embodiment configurations. These terms may reference the same or different embodiments, and unless indicated otherwise, are combinable into aggregate embodiments. The terms “a”, “an” and “the” mean “one or more” unless expressly specified otherwise. The term “connected” means “communicatively connected” unless otherwise defined.
When a single embodiment is described herein, it will be readily apparent that more than one embodiment may be used in place of a single embodiment. Similarly, where more than one embodiment is described herein, it will be readily apparent that a single embodiment may be substituted for that one device.
In light of the wide variety of closure systems known in the art, the detailed embodiments are intended to be illustrative only and should not be taken as limiting the scope of the invention. Rather, what is claimed as the invention is all such modifications as may come within the spirit and scope of the following claims and equivalents thereto.
None of the description in this specification should be read as implying that any particular element, step or function is an essential element which must be included in the claim scope. The scope of the patented subject matter is defined only by the allowed claims and their equivalents. Unless explicitly recited, other aspects of the present invention as described in this specification do not limit the scope of the claims.
To aid the Patent Office and any readers of any patent issued on this application in interpreting the claims appended hereto, the applicant wishes to note that it does not intend any of the appended claims or claim elements to invoke 35 U.S.C. 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim.
This non-provisional application claims priority based upon prior U.S. Provisional Patent Application Ser. No. 62/715,118 filed Aug. 6, 2018 in the name of Brendan Coffey, Michael DeRossi, Jefferson Blake West, Corbett Schoenfelt, Zackary Hickman, and Matthew C. Grossman entitled “Package Closure Systems,” and U.S. Provisional Patent Application Ser. No. 62/778,054 filed Dec. 11, 2018 in the name of Brendan Coffey entitled “Package Closure Design,” the disclosures of each of which are incorporated herein in their entirety by reference as if fully set forth herein.
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