WO2014189513A1

WO2014189513A1 - Closure with hinged lid

Info

Publication number: WO2014189513A1
Application number: PCT/US2013/042415
Authority: WO
Inventors: John M. Wisniewski; Kelly A. Smith
Original assignee: Aptargroup, Inc.
Priority date: 2013-05-23
Filing date: 2013-05-23
Publication date: 2014-11-27
Also published as: AR092256A1

Abstract

A bi-stable, snap-action closure has a body (24) connected with a hinge structure (28) to a lid (26). The hinge structure (28) includes central web portion (100) between two outer tension spring web portions (102). The central web portion (100) has an arcuate configuration that is (1) convex on the exterior side (116) of the central web portion (100) and (2) concave on the interior side (120) of the central web portion (100) when the lid (26) is in a self-maintained stable first position,

Description

CLOSURE WITH HINGED LID

TECHNICAL FIELD

This invention relates to a hinge structure for connecting a lid and body of a closure which can selectively permit or prevent communication between the exterior and interior of a system.

BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART

Closures are employed to selectively prevent or permit communication between the exterior and interior of a system (e.g., machine, equipment, containment system (including bottles and pouches), etc.). A typical closure has a body and a lid (e.g., cap or cover). The closure body defines at least one passage through the body for communicating with the system opening, and the body can be either (1) a separate structure for being attached to the system at the system opening, or (2) a structure formed as a unitary portion of the system at the opening.

The lid accommodates movement relative to the closure body passage between (1) a fully closed position occluding the passage, and (2) an open position at least partially exposing the passage.

One type of closure typically includes a base or body to which a lid is attached with a bi-stable hinge structure. The hinge structure has a snap-action biasing force which maintains the lid in either of two selected positions. One type of a snap-action, bi-stable hinge structure for a container closure is disclosed in the U.S. Patent No. 5,642,824, and that hinge has a narrow central web portion between two wider end portions.

While various snap-action bi-stable hinge structures may function well in many applications, the present invention provides an improved snap-action bi-stable hinge structure for a closure which is especially advantageous when the closure is made from

certain materials. The inventors of the present invention have also determined that it would be desirable to provide an improved bi-stable hinge structure which would operate with less strain and/or be less susceptible to fatigue so as to minimize the likelihood of breakage of the hinge structure and or so as to increase the number of cycles of the hinge structure operation before the hinge structure fails owing to fatigue failure.

For example, in a typical conventional closure having a body and a lid connected by a bi-stable hinge structure that includes a center member defining a pivot axis, the connecting region between the body and the center member may be susceptible to failure above a particular stress level after some number of opening closing cycles of operation.

It would be beneficial if an improved bi-stable hinge structure could accommodate an arrangement that reduces the stress and/or minimizes the likelihood of fatigue failure of the connecting region between a moving portion of the bi-stable hinge structure relative to the connection point at an adjacent, non-movable portion of the hinge structure.

The inventors of the present invention found that it would be especially desirable to provide an improved bi-stable hinge structure that would be less susceptible to fatigue-related delamination effects, particularly with respect to hinge structures molded from polyethylene.

The inventors of the present invention have discovered that it would be particularly advantageous to provide an improved bi-stable hinge structure in which at least certain portions of the hinge structure bend, rather than fold, during operation.

It would also be desirable to provide an improved bi-stable hinge structure which would permit the hinge structure to accommodate or withstand greater stress during operation for a given thickness of material than do some currently known bi-stable hinge structures.

The inventors of the present invention have additionally discovered that permitting a bi-stable hinge structure to operate at a higher stress can result in the hinge structure opening to a larger opening angle at the self-maintained stable open position. Further, it would be advantageous to provide an improved bi-stable hinge structure in

which the opening angle could be increased even if the bi-stable hinge structure is operated at a lower stress.

Additionally, it would be advantageous to provide an improved bi-stable hinge structure in which the stress and strain in the hinge could be better distributed during the closing or opening of the bi-stable hinge structure.

SUMMARY OF THE INVENTION

The present invention provides a closure that can selectively permit or prevent communication between the exterior and interior of a system that has an opening between the exterior and interior. The closure includes a body that is either (1) a separate structure for being attached to the system at the system opening, or (2) a structure formed as a unitary portion of the system at the opening. The body defines at least one passage through the body for communicating with the system opening. The closure also includes a lid for accommodating movement relative to at least one passage between (1) a closed position at least partially occluding the passage, and (2) an open position at least partially exposing the passage.

The closure also includes a hinge structure molded unitary with the body and the lid so as to provide a bi-stable, snap action for urging the lid from an unstable intermediate position to (1) a self-maintained stable first position which the lid assumes after being opened beyond the intermediate position, and (2) a self-maintained stable second position which the lid assumes after being moved beyond the unstable intermediate position toward the closed position.

The hinge structure includes a central web portion having (a) a length extending between the body and lid, (b) a body end connected to the body, (c) a lid end connected to the lid, (d) an exterior side defining a portion of the exterior of the closure, and (e) an interior side oppositely facing from the exterior side.

The hinge structure also includes two outer tension spring web portions each (a) extending between the body and the lid with the central web portion located between the two outer tension spring web portions, (b) having (i) a body end connected to the body,

and (ii) a lid end connected to the lid, and (c) being in greater tension when the lid is in the unstable intermediate position compared to when the lid is in either the self-maintained stable first position or the self-maintained stable second position.

The closure is characterized in that, when the lid is in the self-maintained stable first position, the cross-section of at least a portion of the length of the central web portion between the central web portion body end and the central web portion lid end has an arcuate configuration that is (1) convex on the exterior side of the central web, and (2) concave on the interior side of the central web portion.

In a preferred embodiment, each outer tension spring web portion has an exterior side defining a portion of the exterior of the closure, and each outer tension spring web portion exterior side has an outer lateral edge extending between the body and the lid. Further, a plane LI extends between points PI and P2 when the closure is in the as-molded open configuration wherein for each outer tension spring web portion the point PI is defined by the junction of the body and the outer tension spring web portion exterior side outer lateral edge, and for each outer tension spring web portion the point P2 is defined by the junction of the lid and the outer tension spring web portion exterior side outer lateral edge. When the lid and body are in the as-molded open configuration, the central web portion body end and said central web portion lid end are located at different distances from the plane LI.

Also, in the preferred embodiment, the lid and body have an initially as-molded open configuration produced by two mold parts which close and open. Each outer tension spring web portion has an exterior side defining a portion of exterior of the closure. Each outer tension spring web portion exterior side has an outer lateral edge that (1) extends between the body and the lid, and (2) has a portion defining a straight line segment lying in a common plane L3 with the straight line segment of the other tension spring outer web portion exterior side outer lateral edge when the closure is in the as-molded open configuration. When the lid and body are in the as-molded open configuration, the central web portion body end and the central web lid end are located at different perpendicular distances from the common plane L3.

In the preferred embodiment of the invention, various operational advantages are exhibited. The operational advantages are especially effective and desirable in bi-stable hinge structures that are molded from polyethylene.

In a preferred embodiment of the improved bi-stable hinge structure of the present invention, the strain in parts of the hinge structure can be minimized, and the stress in parts of the hinge structure can be increased, but the susceptibility to failure caused by operational fatigue breakage is reduced.

For use with polyethylene, an embodiment of the improved hinge structure of the present invention can be designed to accommodate higher internal stress levels which can result in a greater opening angle for the lid of the closure when the lid is at the self-maintained stable open position.

In one embodiment of the improved bi-stable hinge structure of the present invention, the strain can be distributed in a more beneficial manner when the hinge structure is closing.

Also, in a preferred embodiment of the improved bi-stable hinge structure, it is possible to minimize fatigue failure at the connecting region between a portion of the hinge structure and the adjacent closure body.

It should be appreciated that the invention may include all or none of the above-described features, or include only one or more of the above-described features, and include any combination of the above-described features. Furthermore, other advantages and features of the present invention will become readily apparent from the following detailed description of the invention, from the claims, and from the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings forming part of the specification, in which like numerals are employed to designate like parts throughout the same,

FIG. 1 is an isometric view of a closure incorporating a hinge structure according to the present invention wherein the isometric view is taken from the upper right side and

top of the front of the closure wherein the closure is shown in a closed condition as initially provided by the manufacturer for subsequent installation on a system (e.g., a container (not illustrated) in which a product is stored);

FIG. 2 is an isometric view taken from the top and rear right side of the closure shown in FIG. 1 ;

FIG, 3 is a rear elevational view of the closure shown in FIG. 1;

FIG. 4 is a top plan view of the closure shown in FIG. 1 ;

FIG. 5 is a cross-sectional view taken generally along the plane 5-5 in FIG. 4;

FIG. 6; is a cross-sectional view taken generally along the plane 6-6 in FIG. 4; FIG. 7 is a greatly enlarged, fragmentary, cross-sectional view of the portion of the structure enclosed in the circle designated "FIG. 7" in FIG. 6;

FIG. 8 is an isometric view of the closure with the lid open in the initially as-molded open condition before the lid is closed;

FIG. 9 is a top plan view of the closure in the as-molded, open condition before the lid is closed by the manufacturer;

FIG. 10 is a side-elevational view of the as-molded, open closure illustrated in

FIG. 9;

FIG. 11 is a cross-sectional view taken generally along the plane 11-11 in FIG.9; FIG. 12 is a cross-sectional view taken generally along the plane 12-12 in FIG. 9; FIG. 13 is a greatly enlarged, fragmentary, cross-sectional view of the portion of the structure enclosed in the circle designated "FIG. 13" in FIG. 11;

FIG. 14 is a greatly enlarged, cross-sectional view generally along the plane 14-14 in FIG. 9;

FIG. 15 is a cross-sectional view generally similar to FIG. 12, but in FIG. 15 the closure lid is shown at the unstable intermediate position; and

FIG. 16 is a greatly enlarged, fragmentary, cross-sectional view of the portion of the structure enclosed in the circle designated "FIG. 16" in FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

While this invention is susceptible of embodiment in different forms, this specification and the accompanying drawings disclose only one specific embodiment as an example of the invention. The invention is not intended to be limited to the embodiment so described, and the scope of the invention will be pointed out in the appended claims.

For ease of description, many figures illustrating the invention show an embodiment of a hinge in a closure in the typical orientation that the closure would have at the opening of a system, such as an upright containment system (which may be, for example, a bottle or other container), and terms such as upper, lower, horizontal, etc., are used with reference to this orientation. It will be understood, however, that the closure may be manufactured, stored, transported, used, and sold in an orientation other than the orientation described.

The closure is suitable for use with a variety of conventional or special systems, the details of which, although not fully illustrated or described, would be apparent to those having skill in the art and an understanding of such systems. The particular systems, per se, that are described herein form no part of, and therefore are not intended to limit, the present invention.

The illustrated embodiment of the closure will typically be used on a system in the form of a containment system that contains a material or substance (e.g., a product such as a lotion, fluid food or drink substance) that can be dispensed, or otherwise removed, from the system through the opened closure. The product may be, for example, a fluent material such as a liquid, cream, powder, slurry, or paste. If the system is a container, and if the container and closure are large enough, then the product could also be discrete pieces of material (e.g., food products such as nuts, candies, crackers, cookies, etc., or non-food products including various items, particles, granules, etc.) which can be removed through an open closure by hand from a container, or scooped out of a container, or ladled out of a container, or poured out of a container. Such materials may be, for example, a food product, a personal care product, an

industrial product, a household product, or other types of products. Such materials may be for internal or external use by humans or animals, or for other uses (e.g., activities involving medicine, manufacturing, commercial or household maintenance, construction, agriculture, etc.).

An embodiment of a hinge in a closure incorporating the present invention is illustrated in the Figures 1-16 wherein the closure is designated generally by reference number 20. In the illustrated embodiment, the closure 20 is provided in the form of a separate closure which is adapted to be attached to a system (not illustrated) in the form of a containment system that would typically contain contents such as a product or products consisting of articles or fluent material.

The system may be a containment system such as a collapsible, flexible pouch, or may be a generally rigid container (which may have somewhat flexible, resilient walls), such as a bottle or tank. The system may be some other system which may include, or be part of, for example, a medical device, processing machine, dispenser, reservoir on a machine, etc., wherein the system has an opening to the system interior.

If the system is a containment system such as a container, then the containment system, or a portion thereof, may be made from a material suitable for the intended application (e.g., a thin, flexible material for a pouch wherein such a material could be a polyethylene terephthalate (PET) film or a polyethylene film, or a thicker, less flexible material for a bottle wherein such a less flexible material could be injection-molded polyethylene or polypropylene).

In applications wherein the closure 20 is mounted to a container such as a bottle or pouch, it is contemplated that typically, after the closure manufacturer makes the closure (e.g., by molding the closure 20 from a thermoplastic polymer), the closure manufacturer will then ship the closure to a containment system filler facility at another location where the container is either manufactured or otherwise provided, and where the container is filled with a product. If the container is a collapsible pouch, then the closure may include a suitable fitment portion that can be attached to the pouch as the pouch is being made and filled, or as the pouch is being made but before the pouch is

subsequently filled through the open closure or through open regions of the pouch walls that are later sealed closed.

In the illustrated embodiment, the closure 20 is provided as a separately manufactured article, component, or unit for being non-removably attached (e.g., mounted or installed) on a system in the form of a containment system defined by a bottle. It will be appreciated, however, that in some applications (not illustrated), it may be desirable for the closure to be attached to a system in a manner that would allow a user to remove the closure from the system. Further, it may be desirable for the closure (or at least the body of the closure) to be formed as a unitary part, or extension, of the system (e.g., a bottle) wherein such a unitary part or extension also (i.e., simultaneously) defines an end structure of the system, per se.

The illustrated embodiment of the closure 20, if initially formed separately from the containment system, is adapted to be attached to a containment system at an opening which provides access from the exterior environment to the container interior and to the contents (e.g., a product contained therein) after a portion of the closure is opened as described hereinafter.

The system, per se. such as a bottle, pouch, or other containment system, or other type of system per se. does not form a part of the broadest aspects of the present invention, per se. The system may have any suitable configuration.

Where the system is a bottle (not illustrated), the bottle typically includes an upper end portion or other suitable structure on some part of the bottle that defines the bottle mouth or opening, and such a bottle upper end portion typically has a cross-sectional configuration with which the closure 20 is adapted to engage. The main body portion of the bottle may have another cross-sectional configuration that differs from the cross-sectional configuration of the bottle upper end portion at the bottle opening. On the other hand, the bottle may instead have a substantially uniform shape along its entire length or height without any portion of reduced size or different cross-section. The bottle may have a generally rigid or flexible wall or walls which can be grasped by the user.

A particular embodiment of the closure illustrated in the Figures is especially suitable for use with a container that is a bottle having a substantially flexible wall or walls that can be squeezed or deflected laterally inwardly by the user to increase the internal pressure within the container so as to force the product out of the container and through the opened closure. In a bottle with a flexible wall or walls, such a flexible wall or walls typically have sufficient, inherent resiliency so that when the squeezing forces are removed, the container walls return to the normal, unstressed shape.

In other applications it may be desirable to employ a generally rigid container, and to pressurize the container interior at selected times with a piston or other pressurizing system to force the product out through the open closure, or to reduce the exterior ambient pressure so as to suck the product out through the open closure.

On the other hand, if the closure 20 has a suitably large access passage or aperture that can be opened to communicate with the containment system interior, then such a closure can be used on a rigid or flexible container from which the contents (e.g., the product) can be accessed through the opened closure and removed by pouring out the contents, or by scooping out the contents, or by withdrawing the contents by hand or with an instrument, etc.

In other applications, contents might be added through the opened closure to the containment system.

In still other applications for use with a system which may be a product containment system or other type of system, the closure can function to permit or prevent the egress or ingress of ambient atmosphere, or other substances, relative to the system on which the closure is installed.

In the illustrated embodiment, the closure 20 includes a closure body 24, a lid 26, and a connecting structure in the form of a hinge structure or hinge 28 which connects the body 24 and lid 26. The closure body 24, lid 26, and hinge structure or hinge 28 are preferably molded together as a unitary structure from a suitable thermoplastic material such as polyethylene, polypropylene, or the like. In a presently preferred form of the closure 20, the body 24, lid 26, and hinge 28 are preferably molded together as a unitary

structure from high density polyethylene (HDPE). Other materials may be employed instead.

The lid 26 is movable between (1) a closed position over the body 24 (as shown in FIGS. 1-6) and (2) an open position (as shown in FIGS. 8-24). In the illustrated embodiment, the lid 26 is connected to the closure body 24 with the hinge structure 28 so as to accommodate a general pivoting movement of the lid 26 between the closed position and an open position.

Typically, the closure 20 is molded by the manufacturer with the lid 26 in an initially wide open position (FIGS. 8-14), and the closure is then said to be in the "as-molded" configuration. Then, after molding the closure 20, the manufacturer moves the lid 26 to the closed position (FIGS. 1-7). The closed closure 20 would typically then be shipped to a pouch manufacturer or bottler which would provide a containment system (e.g., a pouch or bottle, not illustrated), and the pouch manufacturer or bottler would install the closure 20 on the pouch or bottle. The particular containment system may have already been filled with product. Alternatively, the closure may be installed on an empty containment system which is subsequently filled with product through an open bottom end of the containment system which is thereafter sealed closed.

If the containment system is a pouch, then it is presently contemplated that most pouch manufacturers will prefer to install the closure (with a suitable fitment at the lower end) on the pouch with heat sealing techniques. If the containment system is a bottle, then it is presently contemplated that most bottlers would prefer to install the closure 20 on the bottle with the closure 20 suitably configured for snap-fit attachment or threaded attachment as explained below.

The closure body 24 could be modified with various configurations and attachment features (not shown) that might be particularly useful— especially for a container having semi-rigid, resilient walls, or having rigid walls. For example, the closure body 24 can be provided with suitable snap-fit engagement beads 30 (FIG. 5) for engaging complementary or mating features on the container (not illustrated). Such an

engagement would resist removal of the closure 20 by a user of the package. In another alternative (not illustrated), the closure body 24 could have a lower, round end with a thread for threadingly engaging a mating thread of a container.

Further, other means of providing a generally non-removable or removable 5 attachment of the closure 20 to the container (not illustrated) are contemplated. These means could include the use of a suitable mechanical lock system, spin welding of the closure to the container, mechanical staking, adhesive, etc.

The illustrated embodiment of the closure 20 has a closure body 24 with an outer end spout 32 and a through passage 34 as best seen in FIG. 11 which is a cross-sectional

10 view taken generally along plane 11-11 inFIG. 9. The through passage 34 extends from the outer end of the spout 32 and through the rest of the body 24. The through passage 34 communicates with an opening of the bottle (not illustrated) or other system, and the passage 34 permits material (gases, fluids, solids, etc.) to pass between the exterior and the interior of the system.

15 As can best be seen in FIG. 11, the closure body 24 includes a hollow base 36 from which the spout 32 projects outwardly. The through passage 34 extends through both the base 36 and the spout 32. It will be appreciated that the closure body 24 may take a variety of forms, and need not have a discernible spout 32 or base 36 at all. Further, it is understood that the through passage 34 and spout 32 need not be circular as

20 shown. The through passage 34 and/or spout 32 may be elliptical, polygonal, or some irregular shape.

As can be seen in FIG. 11, the inside surface of the front of the lid 26 defines a latch bead 40, and the outer upper edge region of the closure body base 36 defines a latch bead 42. The beads 40 and 42 move against, and slightly past, each other when the lid 25 26 is pushed closed (FIGS. 5 and 6) owing to temporary elastic deformation of the lid 26 and/or body 24. The engaged beads 40 and 42 establish a latched closed position of the lid 26 and prevent the lid 26 from thereafter being opened unless a sufficiently large lifting force is exerted on the lid 26 to effect temporary, elastic deformation on the lid 26

and/or body 24 to permit the lid bead 40 to move past, and above, the body bead 42 as the lid 26 is being moved to an open position.

The closure lid 26 includes a transverse deck or cover 44 (FIG. 11). Extending from the underside of the lid cover 44 is an annular member 48 (FIG. 11) which is adapted to be received on, and sealingly engage the exterior of, the closure body spout 32 when the lid 26 is closed (FIGS. 5 and 6).

The hinge structure 28 is integrally molded as a unitary part of the closure with the body 24 and lid 26. One preferred material for molding the closure is high density polyethylene. It has been found that this material provides a relatively strong, durable closure that is especially suitable for food and drink packaging applications. The high density polyethylene material, when incorporated in the hinge structure 28 as part of the closure of the present invention, (a) accommodates desirable biasing forces, (b) withstands typical (i) impact loads that may be imposed during shipping, and (ii) loads imposed by a user of the closure when the user opens and closes the lid 26, and (c) accommodates a relatively high number of opening and closing cycles without failure.

As illustrated in FIG. 8, the preferred form of the hinge structure 28 includes a central web portion 100 between two center tension spring web portions 102. As seen in FIG. 13, the central web portion 100 has the following elements: (a) a length extending between the body 24 and lid 26, (b) a body end 108 connected to the body 24, (c) a lid end 112 connected to the lid 26, (d) an exterior side 116 defining a portion of the exterior of said closure 20, and (e) an interior side 120 oppositely facing from the exterior side.

In the presently preferred embodiment illustrated, at least a portion of the length of the central web portion 100 has a uniform thickness. The central web portion 100 also preferably has a uniform width along at least a portion of the length of the central web portion 100. The central web portion 100 also is preferably free of apertures. In the presently preferred embodiment, each outer tension spring web portion 102 is separated by a space or gap 125 from the central web portion 100 as can be seen in FIG.

As can be seen in FIGS. 3 and 8, the two outer tension spring web portions 102 each extends between the body 24 and the lid 26 with the central web portion 100 located between the two outer tension spring web portions 102. Each outer tension spring web portion 102 has (i) a body end 130 connected to the body 24 in a pocket 135 (FIGS . 8 and 13), and (ii) a lid end 132 connected to the lid 26.

Each outer tension spring web portion 102 has an exterior side 140 (FIGS. 3 and 13) defining a portion of the exterior of the closure 20. Each outer tension spring web portion 102 exterior side 140 has an outer lateral edge 144 (FIGS. 3, 8 and 14) that (1) extends between the body 24 and the lid 26, and (2) has a portion defining a straight line segments (FIGS. 8 and 13, 8, and 11) lying in a common plane L3 with the straight line segments of the other tension spring outer web portion exterior side outer lateral edge 144 when the closure 20 is in the as-molded open configuration (FIGS. 8-14).

The hinge structure 28 is molded unitary with the body 24 and said lid 26 so as to provide a bi-stable, snap action for urging the lid 26 in either of two directions away from an unstable intermediate position (which may be, for example, approximately the position illustrated in FIGS . 15 and 16). At the unstable intermediate position of the lid 26, the hinge structure 28 may be said to be in an "over-center" configuration wherein the two outer tension spring web portions 102 are each subject to a maximum tension stress and strain. The hinge structure 28 urges the lid 26 from the unstable intermediate position to either (1) a self-maintained stable first position (typically somewhat less than the 180° as-molded open position shown in FIGS. 10 and 11) which the lid 26 assumes after being opened just beyond the over-center, unstable intermediate position, or (2) a self-maintained stable second position (typically somewhat less than the fully latched closed position shown in FIGS. 1, 2, 5, and 6) which the lid 26 assumes after being moved in the closing direction just beyond the unstable intermediate position toward the fully closed position.

Generally, as the lid 26 is moved from an opened to the closed position, and vice versa, the changes in the distance between the body end 130 and lid end 132 of each outer tension spring web portion 102 create a significant tension force or "stretch" in the outer

tension spring web portion 102. This causes the hinge structure 28 to be unstable in any position between the stable first position and the stable second position. This results in the hinge structure 28 having an inherent bias (when the lid 26 is between the two stable positions). This urges the lid 28 to move to the closest of the two stable positions. More specifically, the stretch or tension in the hinge structure outer tension spring web portions 102 serves to create a temporary deformation within the hinge structure 28 that is sufficient to move the lid 26 automatically toward a closed position or toward an open position when it is released from any position between the stable second (closed) position if it is released while it is initially closer to the stable second (closed) position. On the other hand, the lid 26 will automatically move to the stable first (open) position if the lid is released from an initial position which is closest to the stable first (open) position.

If the closure, such as the illustrated closure 20, includes a latching system, such as the lid latch bead 40 and body latch bead 42, then the user must initially exert a sufficient force to move the lid 26 and latch bead 40 upwardly to disengage the lid latch bead 40 from the body latch bead 42 and unlatch the closure. If the user immediately stops applying a lifting force to the lid 26 after releasing the latch beads 40 and 42, then the lid 26 typically would "pop up" slightly to the self-maintained stable second position wherein the lid 26 is substantially closed over the top of the closure body 24, but wherein the lid latch bead 40 has been disengaged from, and is spaced somewhat above, the closure body latch bead 42.

At this initially "popped up" self-maintain stable second position, the stresses in the hinge structure 28 are at a substantially minimum level. In contrast, if the user were to move the lid 26 back down from the initially "popped up" self-maintained stable second position to the fully latched closed position, then the user would have to apply sufficient force to overcome the biasing force of the hinge structure 28, and the user would also have to push the lid 26 downwardly a sufficient amount, and with sufficient force, to again latch the beads 40 and 42. The hinge structure 28 in the fully closed, latched position would be subject to some internal stress that is greater than the minimum

stress level in the hinge structure 28 when the hinge structure 28 is in the initially "popped up" self-maintained stable second position.

If the user opens the lid 26 by disengaging the latch beads 40 and 42 and permits the lid 26 to move to the "popped up" self-maintained stable second position over the closure body 24, then the lid 26 will retain that position unless the user applies a sufficient force to the lid 26 to move the lid 26 further away from the closure body 24. Typically, the user continues to lift the lid 26 from the unlatched, self-maintained stable second position over the closure body 24 toward a more open position that at least partially exposes the closure body passage 34. As the user continues to lift the lid 26, the hinge structure 28 is subjected to increasingly greater internal stresses until the lid 26 reaches the unstable intermediate position wherein the hinge structure 28 is subjected to maximum stresses wherein each outer tension spring web portion 102 is under maximum tension stress and strain— and that is the unstable intermediate position (being approximately illustrated for the closure 20 in FIGS. 15 and 16). At the unstable intermediate position of the lid 26, if the user releases the lid 26, the lid 26 will typically move on its own under the influence of the hinge structure stresses either toward the lower stress self-maintained stable second position (the nearly closed "popped up" position covering the closure body 24) or toward the lower stress self-maintained stable first position (more open position) where the hinge structure 28 has a configuration wherein the stress is also substantially at a minimum.

When the user lifts the lid 26 away from the top end of the closure body 26 beyond the maximum stress unstable intermediate position (approximately the position of the lid 26 shown in FIGS. 15 and 16), then the lid 26 will move under the force of the hinge structure 28 toward the more open, stable first position. The user typically has to pull the lid 26 only slightly beyond the over-center unstable intermediate position toward the more open position because the lid 26 will snap away from the unstable intermediate position toward the more open position under the influence of the hinge structure 28 stresses so that the stresses are reduced to a minimum at the self-maintained stable first (open) position.

The self-maintained stable first (open) position of the lid 26 is typically not as far open as the initially as-molded configuration of the lid 26 shown in FIGS. 8-14. Typically, with reference to FIG. 15, the self-maintained stable first (open) position of the lid 26 might be between about 135° and 160° relative to the plane of the opening of 5 the passage 34 at the top of the closure body 24. The lid 26 typically does not have a self-maintained stable first (open) position that is as wide open as the initially as-molded position of the lid 26 because of strain produced in the hinge structure 28 after the manufacturer initially molds the lid 26 in the wide open condition as illustrated in FIGS. 8-14 and then closes and latches the lid 26 in the fully closed position so that the closure

10 20 can be shipped to a bottler or other system provider. More specifically, the lid 26 typically remains latched fully closed for a substantial period of time (typically days, weeks, or months) before first being opened by an end user. This subjects the hinge structure 28 to some amount of cold forming or "set." Thus, when the lid 26 is first unlatched and fully opened by an end user, the largest opening angle of the lid 26 in the

15 self-maintained stable first (open) position is limited by the cold set permanent

deformation in the hinge structure 28 to an angle (e.g., 135°- 160°) that is somewhat less than the larger open angle of the lid 26 in initially the as-molded wide open condition.

Thus, in terms of the above discussion, the hinge structure 28 provides a bi-stable, snap action for urging the lid 26 from an unstable intermediate position

20 (approximately as shown in FIGS . 15 and 16) to ( 1 ) a self-maintained stable first position which the lid 26 assumes after being opened beyond the intermediate position, and (2) a self-maintained stable second position which the lid 26 assumes after being moved beyond the unstable intermediate position toward the fully closed position. As thus characterized, the self-maintained stable first position of the lid 26 is the position of the

25 lid 26 between the unstable intermediate position and the initially as-molded wide open position (FIGS. 8-14)— and at that stable first position the hinge structure 28 has a substantially minimum stress level. Further, the self-maintained stable second position of lid 26 is that position of the lid 26 between the unstable intermediate position and the fully closed position (which may be a latched closed position as shown in FIGS. 1-7)— and at that stable second position the stress in the hinge structure 28 is again at a substantially minimal level.

According to one aspect of the invention, the snap-action function of the hinge structure 28 is improved in some respects, owing to a special configuration of, at least, the central web portion 100. In particular, and with reference to FIGS. 8 and 13, the central web portion 100 has a special configuration when the lid 26 is in the self-maintained stable first position (i.e., an "opened" position), and that configuration can be characterized as a configuration wherein the cross section of at least a portion of the length of the central web portion 100 between the central web body end 108 and the central web lid end 112 has an arcuate configuration that is ( 1 ) convex on the central web exterior side 116 (FIG. 13), and (2) concave on the central web interior side 120 (FIG. 13). In a preferred embodiment as shown in FIG. 13, at least a portion of the length of the central web portion 100 is preferably has a substantially uniform thickness (top to bottom between sides 120 and 116). Also, preferably, as shown for the illustrated embodiment in FIG. 9, the central web portion 100 has a substantially uniform width along at least a portion of the length of the central web portion 100. Specifically, and with reference to FIGS. 9 and 14, the central web portion 100 may be characterized as having a width defined between two straight sides 160. As can be seen in FIG. 14, the sides 160, in a presently preferred form illustrated, are substantially parallel and substantially vertical compared to the vertical axis of the closure spout 32. However, typically it is desirable to include an 8-10 degree draft angle on each straight side 160 to accommodate removal of the closure 20 from the mold. For example, in order to accommodate one proposed molding method, each side 160 would taper slightly laterally inwardly with increasing distance away from the interior side 120 so that the central web portion exterior side 116 is slightly narrower than the interior side 120. However, even with the use of such draft angles, in the presently preferred form of the hinge structure 28 illustrated in FIG. 14, the sides 160 of the central web portion 100 may also be characterized as being "generally perpendicular" to (1) the plane defined by the top of the spout 32 or to the plane defined by the bottom end of the closure body 24; and (2) the previously described plane L3 (FIGS. 13 and 14) as previously defined in the discussion of the outer lateral edge 144 of each outer tension spring web portion 102.

In the presently preferred form of the hinge structure 28 illustrated in the figures, the central web portion 100 is free of apertures, and, as can be seen in FIG. 14, the central web portion 100 is symmetrically located laterally (i.e., left to right, or right to left, as viewed in FIG. 14) relative to the outer tension spring web portions 102. The outer tension spring web portions 102 are each separated by a space 125 from the central web portion 100 as can be seen in FIGS. 3 and 14. In an alternative embodiment not illustrated, the separation spaces or gaps 125 between the central web portion 100 and each outer tension spring web portion 102 could be eliminated. That is, the hinge structure could be defined by a single unitary web without gaps or apertures and wherein the two outer tension spring web portions 102 would join and merge with the central web portion 100 at the locations where the gaps or spaces 125 presently exist as shown in FIG. 14.

In the presently preferred form of the hinge structure 28 illustrated in FIG. 14, the thickness of the central web portion 100 and of each of the two outer tension spring web portions 102 can be substantially the same in the middle of the hinge structure (as viewed along the view line 14-14 in FIG. 9), although the thickness of each outer tension spring web portion 102 may be slightly thicker or slightly thinner than the central web portion 100 in some applications.

In the presently preferred embodiment illustrated in FIGS. 1-16, the hinge structure 28 preferably also includes another feature related to the configuration of the central web portion body end 108 and the central web portion lid end 112 as best illustrated in FIG. 13. In particular, as can be seen in FIG. 13 , the central web portion body end 108 and the central web portion lid end 112 are located at different perpendicular distances from the previously described plane L3. That is, with reference to FIG. 13, the right hand end of the central web portion 100 is higher than the left hand end of the central web portion 100 when the lid 26 is in an open condition. More specifically, consider FIG. 13 wherein the lid 26 is shown in the as-molded, open

configuration. As previously explained, after the lid 26 is initially closed by the manufacturer and subsequently opened by a user, the lid 26 typically does not stay in a self-maintained opened configuration that is as wide open as the original as-molded open configuration. Rather, the self-maintained stable first position ("opened" position) is typically less than the 180° open position that the lid 26 typically would have in the initial as-molded configuration. When the user first opens the lid 26 (after the lid 26 had been first closed by the manufacturer), the lid 26 may have a self-maintained stable location at an opening angle of 150° or 160°, for example, relative to the closure body 24, and that lesser opening angle is typically the result of the closure hinge structure 28 having taken somewhat of a "cold set" permanent deformation that results in the self-maintained stable open position being somewhat less than the initially wide open, as molded position shown in FIG. 13. In any event, regardless of whether a self-maintained, stable open position of the lid 26 is either the initially, as-molded open position or a less open stable position (resulting from being subsequently closed and opened) corresponding to a self-maintained stable first position, the central body portion lid end 112 is "higher" than the central web portion body end 108.

Another way of characterizing the difference in height locations of the central web portion body end 108 and central web portion lid end 112 is to describe that height difference in relation to a parting plane defined on the as-molded configuration of the closure 20 by two co-acting mold parts. In FIGS. 10, 12, and 14, the parting plane is indicated by the line L2. Thus, with reference to FIG. 13, the central web portion body end 108 is further from the parting plane line L2 than is the central web portion lid end 112 when considering the initially, as-molded open configuration of the closure 20.

Another way to consider the difference in relative height locations of the central web portion body end 108 and central web portion lid end 112 is to view the locations of those end portions relative to the line LI (FIGS. 13 and 14) wherein LI represents a plane extending between points PI and P2 (FIGS. 10 and 14). With reference to FIGS. 10 and 14, the point PI for each outer tension spring web portion 102 is defined by the junction of the closure body 24 and the outer tension spring web portion exterior side

outer lateral edge 140. The point P2 for each outer tension spring web portion 102 is defined by the junction of the lid 26 and the outer tension spring web portion exterior side outer lateral edge 140. When the body 24 and lid 26 are in the as-molded open configuration (FIGS. 8, 10, 13, and 14), the central web portion body end 108 and the central web portion lid end 112 are located at different distances from the plane indicated by the line LI (FIGS. 10, 12, 13, and 14).

FIGS. 15 and 16 show the unstable, intermediate position of the closure lid 26 relative to the body 24 wherein the outer tension spring web portions 102 are each in a condition of minimum stress as previously explained. In FIG. 16, the lines or planes LI and L3 are shown as having been moved with the closure lid 26 and hinge structure 28 from the as-molded open configuration (FIGS. 10, 13, and 14) to the over-center unstable, intermediate position. For this preferred illustrated embodiment, even at the unstable, intermediate position, the central web portion lid end 112 is further from the planes represented by LI and L3 than is the central web portion body end 108. It will also be appreciated that in another form of the invention (not illustrated), the height relationship between the central web portion body end 108 and central web portion lid end 112 could be reversed. That is, with reference to FIG. 13, the central web portion lid end 112 could be lower than the central web portion body end 108 so that the central web portion lid end 112 would be further from the parting plane line L2 and the central web portion body end 108, and so that the central web portion lid end 112 would be closer to the planes LI and L3 than the central web portion body end 108.

The above-described aspects of the present invention, depending upon the extent to which some or all of the features are incorporated in a closure, can provide a number of advantages. Such advantages include compatibility with polymers which tend to delaminate with repeated folding, such as polyethylene.

The presently preferred, illustrated embodiment of the invention is designed to operate in a manner in which the central web portion 100 "bends" as the lid 26 is moved through its range of movement from open to closed and from closed to open. That bending action is different from the "folding" action that is seen in some other types of

snap-action hinges which experience fatigue failure at such a "folding" line or region after some number of "open-closed-open" cycles. Such a fatigue failure at a bending line or bending region in a conventional snap-action hinge is more pronounced and happens at a lower number of cycles when the closure is made from some materials and maintained at lower temperatures (e.g., a hinge in a food product container closure that is molded from polyethylene and maintained at conventional refrigeration temperatures). Conventional high-density polyethylene hinge structures on some closures may typically break at between about 10 and about 20 opening/closing cycles after they have been refrigerated for about 24 hours at 42°F.

The inventors of the present invention have also found that, with the preferred embodiment of the present invention as illustrated, the central web portion 100, owing to its "bending" action during opening and closing, does not produce a typical crease of fold line which occurs in some conventional snap-action hinge closures. Such a crease typically results from the elastic limit of the polymer being exceeded so that the polymer is subjected to a sufficient amount of permanent plastic deformation which results in a "stress whitening" in the central pivot connection member which is esthetically objectionable.

The inventors of the present invention have determined that when one or more of the above-described inventive features are included in a closure, the design target stress levels for the hinge structure can be increased (and this is believed to occur because the central web portion 100 is more resilient due to lower stresses that are experienced as a result of the configuration of the inventive hinge structure 28).

Further, the inventors have found that a closure embodying one or more features of the preferred embodiment of the invention can have a greater opening angle (compared to conventional snap-action hinge structures) regardless of the operating stress level within the hinge structure.

The inventors have also found that the illustrated preferred embodiment of the closure 20 of the present invention functions to have a better strain distribution in the hinge structure 28 when the lid 26 is closed owing to the arcuate shape of the central web

portion 100 and the lower pocket 135 (FIGS. 8 and 13) on the body 24. The pocket 135 on the body 24 allows for a large radius on the top side of the central web portion 100 at the central web portion body end 108, and this reduces the stresses at the central web portion body end 108 so as to minimize the likelihood of fatigue failure there when the closure 20 is operated through many cycles of opening and closing, even at refrigeration temperatures.

The inventors of the present invention have also found that with the preferred embodiment of the closure 20 as illustrated, the self-maintained second ("closed") position of the lid 26 is closer to the closure body 24 than with some other conventional snap-action hinge closures. This results in a reduced "lid gap" for the preferred embodiment of the present invention when the lid 26 is in the self-maintained stable second position.

The inventors of the present invention have found further that the preferred embodiment of the illustrated closure can accommodate designs wherein the central web portion 100 and outer tension spring web portions 102 can be made thinner (e.g.,

0.012-0.014 inch thick) compared to conventional snap-action hinge webs which may have a thickness of between about 0.016 and about 0.020 inch.

A closure with the inventive hinge structure features of the present invention is especially suitable for being molded from high density polyethylene. Compared to low density polyethylene, high density polyethylene is preferred for its rigidity and resistance to warping (such as might occur when a closure is installed on a container of product to create a package, and a plurality of such packages are packed in stacked shipping cartons such that weight forces during shipping can cause warping of the closure). Warping can cause the closure body to become slightly oval during shipping. However, compared to low density polyethylene, a closure molded from high density polyethylene typically returns substantially completely to the original shape after the shipping weight forces are removed, and the packages are unloaded from the shipping container.

The present invention can be summarized in the following statements or aspects numbered 1-11:

Claims

-28-

WHAT 18 CLAIMED IS:

1 , A closure (20) that can selectively permit or prevent coninumication between the exterior and interior of a system that has an. opening between the exterior and interior, said closure (20) comprising:

(A) a body (24) that is either (1) a separate structure for being attached to said system at said system opening, or (2) a structure formed as a unitary portion of said system at said opening, said body (24) defining at least one passage (34) through said body (24) for communicating with said system opening;

(B) a lid (26) for accommodating movement relative to said at least one passage (34) between (1) a closed position at least parti ally occluding said at least one passage (34), and (2) an open position at least partially exposing said at least one passage (34); and

(C) a hinge structure (28) molded unitary with said body (24) and said lid (26) so as to provide a bi-stable, snap action for urging said lid (26) from an unstable intermediate positio to

( 1 ) a self-maintained stable first position which said lid (26) assumes after being opened beyond said intermediate position, and

(2) a self-maintained stable second position which said lid (26) assumes after being moved beyond said unstable intermediate position toward said closed position, and

wherein said hinge structure (28) includes

( 1 ) a central web porti on ( 100) having

(a) a length extending between said body (24) and lid

(26),

(b) a body end (108) connected to said body (24),

(c) a lid end (112) connected to said lid (26),

(d) an exterior (116) side defining a portion of the exterior of said closure (20), and -29-

(e) an interior side (120) oppositely facing from said exterior side (116); and

(2) two outer tension spring web portions (102) each (a) extending between said body (24) and said lid (26) with said central web portion (100) located between said two outer tension spring web portions

(102), (b) having (i) a body end (130) connected to said body (24), and (ii) a lid end (132) connected to said lid (26), and (c) being in greater tension when said lid (26) is in said unstable intermediate position compared to when said lid (26) is in either said self-maintained stable first position or said self-maintained stable second position; and wherein said closure (20) is characterized in that, when said lid (26) is in said

self-maintained stable first position, the cross- section of at least a portion of said length of said central web portion (100) between said central web portion body end (108) and said central web portion lid end (1 12) has an arcuate configuratioii that is (I) convex on said exterior side (1 16) of said central web portion (100), and (2) concave on said interior side (120) of said central web portion (100).

2. The closure (20) in accordance with claim 1 in which

said lid (26) and body (24) have an initially as-molded open configuration defining a parting plane produced by mold parts which close and open relative to said parting plane L2; and

when said lid (26) and body (24) are in said as-molded configuration, said central web portion body end (108) and said central web portion lid end (112 are located at different perpendicular distances from said parting plane L2.

3. The closure (20) in accordance with claim 12- in which

said lid (26) and body (24) have an initially as-molded open configuration; each said outer tension spring web portion (102) has an exterior side (140) defining a portion of the exterior of said closure (20); -30- each said outer tension spring web portion exterior side (140) has an outer lateral edge (144) extending between said body (24) and said lid (26);

LI is a plane extending between points PI and P2 when said closure (20) is in said as-molded open configuration wherein

said point PI is defined for each said outer tension spring web portion

(102) by the junction of said body (24) and said outer tension spring web poriion exterior side outer lateral edge (144), and

said point P2 is defined for each said outer tension spring web portion_by the junction of said lid (26) and said outer tension spring web portion exterior side outer lateral edge (144); and wherein,

when said lid (26) and body (24) are in said as-molded open configuration, said central web portion body end (108) and said central web portion lid end (112) are located at different distances from said plane LL 4. The closure (20) in accordance with claim 3 in which at least a portion of the length of said central web portion (100) has a uniform thickness, and said central web portion lid end (112) is located further from said plane LI than is said central web portion body end (108) by a distance that is equal to at least one-half of the thickness of said eentrai web portion (100).

5, The cl osure (20) in accordance with any of the preceding claims in which said arcuate configuration of said at least a portion of said length of said central web portion (100) has a uniform thickness. 6. The closure (20) in accordance with any of the preceding claims in which said eentrai web portion (100) has a uniform width along at least a portion of said length of said central web portion (100). -31-

7. The closure (20) in accordance with an of the preceding claims in which said closure is molded from one of the group of materials consisting of polypropylene and polyethylene. 8. A closure (20) in accordance with any of the preceding claims in which said centra! web portion (100) is free of apertures.

^■9. The closure (20) in accordance with any of the preceding claims in which said closure (20) is a dispensing closure (20) for use on a system defined by a container defining said opening wherein said body (24) is separate from, but releasably attachable to, said container around said opening,

10. The closure (20) in accordance with any of the preceding claims in which each said outer tension spring web portion (102) is separated by a space (125) from said central web portion ( 100).

11. The closure (20) in accordance with any of the preceding claims in which said lid (26) and body (24) have an initially as-molded open configuration produced by mold parts which close and open;

each said outer tension spring web portion (102) has an exterior side (140) defining a portion of the exterior of said closure (20);

each said outer tension spring web portion exterior side (140) has an outer lateral edge ( 44) that (1) extends between said body (24) and said lid (26), and (2) has a portion defining a straight line segment lying in a common plane L3 with said straight line segment of the other outer tension spring outer web portion exterior side outer lateral edge (144) when said closure (20) is in said as-molded open configuration; and

when said lid (26) and body (24) are in said as-molded open conf guration, said central web portion body end (108) and said central web portion lid end (112) are located at different perpendicular distances from said common plane L3.