REMOVABLE AND REUSABLE CONTAINER CLOSURE WITH VENT

RELATED APPLICATION

[0001] This application is related to and claims priority from United States Application No. 11/075,788 filed March 9, 2005, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates generally to removable closures for containers, and more particularly, to removable and reusable vented closures for use with micro wavable containers.

BACKGROUND OF THE INVENTION

[0003] It is known to provide a microwavable food container with a lid to be secured to the container during the microwave heating process. The lid functions to reduce the potential for contents of the container spilling or boiling over during the heating process.

[0004] It would be desirable to provide a lid having features which further reduce potential spilling or boiling over of the container contents during the microwave heating process.

SUMMARY OF THE INVENTION

[0005] In one aspect, the invention is a closure for a container having an upper end and a lip proximate to the upper end. The closure comprises a top having a first substantially planar portion defining a first plane and a second substantially planar portion defining a second plane. The first plane is displaced from the second plane such that the

first and second portions are offset from one another. At least one vent hole is located in the first portion. At least one locking lever is provided and includes an inwardly projecting locking wedge. An elastically deformable hinge connects the locking lever to the top. The hinge permits pivotal movement of the locking lever between a latched position and an unlatched position. A skirt is connected to the top and has an upper edge and a lower edge. The first plane is preferably near the upper edge and the second plane is intermediate the upper edge and the lower edge. The first and second portions are concentric, with the second portion surrounding the first portion and an outer extent of the second portion being connected to the skirt. The locking wedge is adapted to releasably engage the container lip in the latched position and disengage the container lip in the unlatched position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For the purpose of illustrating the invention, there is shown in the drawings forms that are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and constructions particularly shown.

[0007] Figure 1 is a perspective view of a container closure according to a first preferred embodiment of the present invention, shown installed on a container.

[0008] Figure 2 is a perspective view of the closure of Figure 1 shown removed from the container.

[0009] Figure 3 is a top plan view of the closure of Figure 1.

[0010] Figure 4 is a cross-sectional view of the closure and upper portion of the container of Figure 1, taken along line 4-4 of Figure 3, with the closure shown separated from the container.

[0011] Figure 5 is a cross-sectional view of the closure and upper portion of the container of Figure 1, taken along line 5-5 of Figure 3, with the closure shown separated from the container.

[0012] Figure 6 A is the enlarged detail view of a locking lever of the closure of Figure 1, taken along line 6A-6A of Figure 3, with the closure shown separated from the container and showing the locking lever rotated into a latched position.

[0013] Figure 6B is an enlarged detail view of a locking lever of Figure 6A ₅ with the closure shown connected to the container and showing the locking lever rotated into an unlatched position.

[0014] Figure 7 is a perspective view of a closure in accordance with a second preferred embodiment of the present invention.

[0014.1] Figure 8 is a perspective view of a container disposed in combination with an container closure according to one embodiment of the present invention.

[0014.2] Figure 9 is an isolated perspective view of one embodiment of the closure including a pair of locking levers disposed about the periphery of a central sealing cap.

[0014.3] Figure 10 is a top view of the closure shown in Fig. 9.

[0014.4] Figure 11 is a cross-sectional view of the closure taken substantially along line

4-4 of Fig. 10.

[0014.5] Figure 12 is an enlarged sectional view along an edge of the closure for illustrating one of the locking levers disposed in combination with a raised lip of the container.

[0014.6] Figure 13 is the same enlarged view of Fig. 12 illustrating the operation of the locking lever (i.e., the motion of the locking lever shown in dashed lines) and certain structural features including various angles for guiding and retaining the locking lever.

[0014.7] Figure 14 depicts a top view of an arcuate section of the closure.

[0014.8] Figure 15 is an isolated perspective view of another embodiment of the closure including three such locking levers disposed in equiangular increments about the sealing cap.

[0014.9] Figure 16 is an isolated perspective view of an alternate embodiment of the closure according to the present invention including an opening for dispensing the container contents and a hinged cover plate for closing and sealing the opening.

[0014.10] Figure 17 is an isolated perspective view of the closure of Fig. 16 with the hinged cover plate and vent tab shown in an open position.

DETAILED DESCRIPTION OF THE DRAWINGS

[0015] Referring now to the drawings wherein like reference numerals identify like elements, components and subassemblies, Figure 1 depicts a container 4 in combination with a vented end closure 10 according to the present invention. The container 4 has an upper end 6 having an open mouth. Preferably, the open mouth is provided with a conventional frangible or removable seal 7, which may be removed by a user to expose contents (not shown) of the container 4. One example of a removable seal is a peel-off film that is sealed to the rim of other edge of the container. With the seal 7 removed, the closure 10 may be attached to the upper end 6 during heating of the container contents to reduce potential for spillage or boiling over of the contents, while allowing heated gases generated during the heating process to escape from the container.

[0016] The container 4 may be of any size or shape and may be fabricated from any one of a variety of materials. Preferably, the container 4 contains food products which are heated in a microwave oven prior to consumption. Therefore, the container 4 is preferably fabricated from a material suitable for storage of food products and for microwave use. The container 4 includes a raised lip 8, or similar structure proximate to its upper end 6. The raised lip 8 may be disposed directly adjacent the upper end 6 of the container 4 or in close proximity thereto. For example, should the container 4 employ a threaded end, the raised lip 8 may be disposed above or below the threaded connection. Furthermore, while the container 4 and closure 10 are illustrated as each having a substantially circular cross- section, it will be appreciated that the teachings of the invention are applicable to a variety of other cross-sectional shapes including, for example, elliptical or polygonal shapes. The following description and alternate embodiments of the invention are not intended to describe all closure/container combinations, but are merely illustrative of how the teachings of the present invention may be employed in the context of a variety of container configurations.

[0017] For the purposes of defining direction and/or angular orientation, it will be useful to define a cylindrical coordinate system, wherein a Z-axis is coincident with a longitudinal axis 4A of the container 4. Displacement in, or spatial orientation relative to, the Z-axis is referred to as "axial" displacement or position, while displacement or spatial

orientation along a radius R from the Z-axis will be referred to in terms of "radial" displacement or position. Furthermore, before discussing the functional characteristics of the various elements, it will be useful to provide a brief overview of the structural features, such as the geometry, spatial relationships and orientation, of the closure 10 according to the present invention.

[0018] With reference initially to Figures 1-3, the closure 10 includes a top 12, at least one, and preferably two or more locking levers 14 disposed radially outboard of the top 12, and an elastically deformable hinge 16 (best seen in Figure 3) connecting the top 12 and each of the locking levers 14. The hinge 16 preferably includes two circumferentially spaced apart webs 16 A, 16B which help to stabilize the locking levers 14 for providing controlled locking of the closure to the container 4. The use of two (or more) webs for each locking lever 14 helps to dissipate or reduce the heat that passes to the locking lever 14. The webs 16 A, 16B are separated by a hole or slot 16C. Providing slot 16C makes the hinge 16 more flexible, and reduces the amount of force required to move the locking levers 14. Stated otherwise, the slots 16C allow the locking levers 14 to extend through a larger arc, while reducing the amount of force required to move the locking levers 14 compared to the amount of force which would be required if the hinge 16 had a continuous web.

[0019] In the described embodiment, the top 12 includes a sealing ring 22, which provides a seal between the top 12 and the container lip 8 when the closure 10 is installed on the container 4. Alternatively, sufficient sealing between the top 12 and container lip 8 could be provided by the hinge 16 and the locking levers 14 such that the sealing ring 22 could be omitted. That is, if the locking levers 14 develop a sufficiently robust connection between the closure 10 and the container 4, an adequate seal could be realized between a lower side of the top 12 and an upper extent of the lip 8. The closure 10 preferably includes a skirt 23, preferably formed by first and second skirt segments 23a, 23b. The skirt 23 is connected to a periphery of the top 12.

[0020] With particular reference to Figs. 3 and 4, the top 12 has a first portion 40 and a second portion 50. Preferably, the first and second portions 40 and 50 are both substantially planar, defining a first plane 42 and a second plane 52, respectively. The

first and second planes 42, 52 are non-coincident. Preferably, the first and second planes 42, 52 are substantially parallel, and are displaced from one another by a displacement or offset δ (see Figure 4). In the embodiment illustrated, the first portion 40 has an outer extent 44, and the second portion 50 has an inner extent 54 and an outer extent 56. Furthermore, in the embodiment illustrated, the first and second portions 40, 50 are concentric, with the second portion 50 surrounding the first portion 40. The second portion outer extent 56 preferably connects to the skirt 23. It should be readily apparent that, although the first and second portions are planar in the illustrated embodiment, it is contemplated that the portions may be curvilinear or other contoured shape.

[0021] A transition section 70 is preferably provided between the first and second portions 40, 50. The transition section 70 connects the first portion outer extent 44 to the second portion inner extent 54. The transition section 70 may be shaped in various ways, including a frustoconical shape as illustrated.

[0022] At least one vent hole 60, and preferably a plurality of vent holes 60 are provided in the first portion 40. The total vent area provided by the vent holes is not critical, with satisfactory performance being realized with the total vent area ranging widely, including a range from about 0.05 square inches up to about 0.50 square inches. As discussed herein below, the vent holes 60 operate to relieve gas pressure within the container 4 and closure 10 generated during the heating process.

[0023] With particular reference now to Figure 4, the skirt 23 has a first, upper edge 80 and a second, lower edge 82. The upper edge 80 preferably defines an upper plane. As illustrated, the first plane 42 defined by the first portion 40 is preferably near the upper edge 80, while the second plane 52 defined by the second portion 50 is intermediate the upper edge 80 and lower edge 82. The first plane 42 could be substantially coincident with the upper edge 80, or could lie slightly below the upper edge 80.

[0024] With continued reference to Figure 4 along with Figure 6A, the sealing ring 22 is illustrated to have a first, upper end which connects to an underside surface of the top 12. When assembled with the container 4, the sealing ring 22 projects toward the upper end 6. A portion of the sealing ring 22 defines a sealing surface 24 adapted to detachably

mate or contact with an interior surface 28 of the container lip 8. In the illustrated embodiment, the sealing surface 24 and interior surface 28 lie along substantially parallel planes. However, alternatively the contact surfaces 24, 28 could be formed to lie along planes that are at an acute angle with respect to one another to provide an interference fit and enhance sealing between the sealing surface 24 and the interior surface 28.

[0025] Referring to Figs. 3 and 5, at least one and preferably two or more locking levers 14 are disposed about the periphery of the top 12. Preferably, if there are two levers, the levers 14 are positioned to be substantially diametrically opposed about the circumference {i.e., spaced approximately one-hundred and eighty degrees apart). However, alternatively, the levers 14 may be spaced in unequal increments depending upon the particular application.

[0026] The locking levers 14 may have any of a number of various shapes. For example the locking levers 14 may have a shape in the circumferential direction that is either linear or arcuate depending upon the desired top configuration. With reference to Figure 3, a top view of a locking lever 14 shows the curvature or arcuate shape of the lever 14 conforming to the circumferential periphery of the skirt 23. When employed with a circular closure 10, each locking lever 14 preferably has an arc length extending over an included angle φ. The included angle φ is preferably in the range of about 10 to about 15 degrees.

[0027] With reference now to Figures 6 A and 6B, each locking lever 14 includes actuation and lower locking arms, 30 and 32, respectively. The actuation arm 30 extends in one direction (upwardly, as illustrated) from the deformable hinge 16, while the lower locking arm 32 generally extends in the opposing direction, (downwardly, as illustrated) from the hinge 16. The deformable hinge 16 is located between or intermediate the actuation and lower locking arms 30, 32 and provides a pivotal connection about which each locking lever 14 may pivot.

[0028] Each locking lever 14 includes a locking wedge 36. The wedge 36 includes a sloped guide surface 36G and a retaining surface 36R. The wedge 36 is sized, shaped, and

positioned on the locking lever 14 to releaseably engage the container lip 8 when the closure 10 is installed on the container 4 and to secure the closure 10 to the container 4.

[0029] Operation of the latching levers 14 to attach the closure 10 to and to detach the closure 10 from the container 4 is now described with particular reference to Figs. 6A and 6B. The description is applicable to the specific embodiment shown in the figures, however, the fundamentals generally apply to the alternate embodiments as well. Initially, the closure 10 of the present invention is aligned with the upper end 6 of the container 4 such that the lower locking arms 32 and sealing ring 22 are adjacent the container lip 8. The closure 10 then is pressed axially downward against the container lip 8 such that the guide surfaces 36G of the locking wedges 36 ride over an external surface of the lip 8. The deformable hinge 16 facilitates displacement of the lower locking arms 32 of the levers 14 from a latched position 14A into an unlatched position 14B, as each locking wedge 36 passes the container lip 8. More specifically, the axial displacement of the closure 10 effects radial displacement of the lower locking arms 32 until the vertex of the wedge 36 passes the lower edge 8LE of the container lip 8. Once the vertex of each wedge 36 passes the container lip 8, the inherent memory of the deformable hinge 16 causes the locking wedges 36 to displace radially inwardly, back into the latched position 14 A, toward the principle Z-axis of the container 4. More specifically, the elasticity of the deformable hinge 16 rotates the levers 14 into the latched position 14A to cause the locking wedges 36 to engage the container lip 8. The guide surfaces 36G facilitate engagement of the closure 10 without the requirement to align the sealing surfaces 24, 28 or actuate the locking levers 14. That is, the guide surfaces 36G are sloped downward and away from the lower locking arm 32 to facilitate self-actuation of the locking lever 14. Thus, engagement of the closure 10 to the container 4 may be performed by one hand.

[0030] Disengagement of the closure 10 is effected by pressing the actuation arms 30 of the locking levers 14 radially inwardly to pivot the lower locking arms 32 into the unlatched position 14B. The radially inward displacement of the actuation arms 30 causes the locking arms 32 to disengage from the container lip 8. Movement of the levers 14 into the unlatched position 14B can generally be performed with the thumb and forefinger of the same hand, while the container 4 is held in the other hand. With the locking wedges

14 disengaged from the container lip 8, the closure 10 may be axially separated from the container 4.

[0031] Referring again to Figure 2, the locking levers 14 preferably include a textured surface 11, such as a series of protrusions or dimples, that provide a gripping surface for the user's fingers. The textured surface 11 assists in inhibiting the user's fingers from slipping off the levers as they actuate the levers 14.

[0032] The closure 10 is preferably manufactured as an integral, unitary structure from a polymeric material. That is, the top 12, locking levers 14, and deformable binges 16 are preferably fabricated as a single unit to form a unitary structure. Polypropylene is a particularly preferred material. Preferably, a conventional, low-cost fabrication technique, such as injection molding, is used to fabricate the closure 10.

[0033] In use, the container 4 is preferably provided to the consumer/user with the closure 10 attached (see Figure 1). When the user is ready to heat the contents of container 4, the user first removes the closure 10, and then removes the seal 7, creating an open mouth at the container upper end 6. The closure 10 is then re-installed on the container 4, and the assembly of the container and closure is placed in a microwave oven for heating. During the heating process, gases within the container expand. Without the vent holes 60, the gases within the container could pressurize the interior of the container 4 to such a level as to disengage the closure 10 from the container 4. Additionally, without sufficient heat dissipation, the temperature of the lid can rise, creating a potentially hazardous condition when the user attempts to remove the product form the microwave. Furthermore, with the closure 10 disengaged, the potential for boiling over or other spillage of container contents both during and after the heating process is increased. Thus, the vent holes 60 assist in maintaining engagement of the closure 10 with the container 4 during heating process. With the closure 10 engaged with the container 4, the potential for spillage or boiling over of the contents being heated is reduced.

[0034] Furthermore, locating the vent holes 60 in the first portion 40 of the top 12 also reduces potential for spillage and boiling over of the contents while being heated. With the first portion 40 displaced from and elevated above the second portion 50, the contents

of the container 4 have farther to travel to reach the vent holes 60. The elevated position of the vent holes 60 reduces the probability of contents escaping through the vent holes. Also, locating the vent holes 60 centrally reduces the potential for spillage. If the vent holes 60 were positioned toward the periphery of the top 12, a relatively minor tilting of the container 4 and closure 10 would result in overflow of the contents through the vent holes 60, while with the vent holes 60 positioned centrally, a more pronounced tilting of the container 4 and closure 10 is required for the contents to overflow through the vent holes 60. Moreover, placement of the holes near the center provides a chimney effect directing the pressure and heat in a single direction and away from the actuation arms. This minimizes temperature increase in the arms.

[0035] A second embodiment closure 10' is depicted in Figure 7. The second embodiment closure 10' is substantially similar to the first embodiment closure 10, but comprises three (3) locking levers 14 preferably spaced at equal angular increments about the periphery of the central top 12. It will be appreciated that three fingers, working together, will be required to move the locking levers 14 from the latched position 14A to the unlatched position 14B.

[0036] The present invention thus operates to reduce the potential for spillage from the container both during and subsequent to the heating process. The locking levers 14 operate to prevent axial separation of the closure 10 from the container 4.

[0037] Fig. 8 depicts a further embodiment of a container 104 in combination with an end closure 110 according to the present invention for closing an open end 106 of the container 104. The container 104 may be of any size or shape, may be used for holding any material, e.g., food or non-food product, and may be fabricated from any one of a variety of materials. The only specific requirement, however, is that the container 104 employ a raised lip 108, e.g., a rim, flange or other similar structure proximate to its open end 106. The raised lip 108 may be disposed directly adjacent the open end 106 of the container 104 or in close proximity thereto. For example, should the container 104 employ a threaded end, the raised lip 108 may be disposed above or below the threaded connection. An example of such a threaded connection will be illustrated later in the detailed description when discussing alternate embodiments. Furthermore, while the

container 104 and closure 110 each have a substantially circular cross-section, it will be appreciated that the teachings of the invention are applicable to a variety of other cross- sectional shapes including, for example, elliptical, polygonal, etc. The following description and alternate embodiments of the invention are not intended to describe all closure/container combinations, but merely illustrative of how the teachings of the present invention may be employed in the context of a variety of container configurations.

[0038] For the purposes of defining direction and/or angular orientation, it will be useful to define a cylindrical coordinate system Z-R wherein the Z-axis is coincident with the longitudinal axis 104A of the container 104. Displacement in, or spatial orientation relative to, the Z-axis is referred to as "axial" displacement or position, while displacement or spatial orientation along radials R from the Z-axis will be referred to in terms of "radial" displacement or position. Furthermore, before discussing the functional characteristics of the various elements, it will be useful to provide a brief overview of the structural features, such as the geometry, spatial relationships and orientation, of the closure 110 according to the present invention.

[0039] In Figs. 9-11, the closure 110 includes a cap 112, at least two locking levers 114 disposed radially outboard of the cap 112, and an elastically deformable hinge 116 (best seen in Fig. 11) connecting the cap 112 and each of the locking levers 114. Generally, the cap 112 may be viewed as the portion of the closure 110 which preferably provides and air- or fluid-tight seal between the container 104 and the closure 110. In the described embodiment, the cap 112 comprises a cover 120 and an annular or ring member 122, which may provide a seal between the cap 112 and lip 108 of the container. Alternatively, sufficient sealing may be provided by the hinge 116 and the locking levers 114, i.e., to the extent that an edge of the cap 112 and lip 108 of the container 104 are closely aligned. As shown, the cover 120 is solid and impervious to air and/or liquid, however, as will be seen in alternate embodiments of the invention, the cover 120 may include one or more openings for dispensing or venting the material/product within the container 104. Finally, the cap 112 may include a segmented outer ring 123a, 123b for providing an aesthetically pleasing geometric appearance.

[0040] In Figs. 10-12, the sealing ring 122 projects axially downwardly, i.e., toward the opening 106 of the container 104, and preferably defines a sealing surface 124 (Fig. 12) adapted to detachably mate or contact with an interior surface 128 of the container lip 108. In one embodiment, the sealing surface 124 lies along a plane that is substantially the same as the interior surface 128. In another embodiment, the contact surfaces 124, 128 lie along planes that are at an acute angle α with respect to one another so that upon placement of the cap on the container, the sealing surface 124 will come into contact with the inner surface 128 of the container 104.

[0041] In Fig. 12, each locking lever 114 includes actuation and lower locking arms, 130 and 132, respectively. The actuation arm 130 extends in one direction e.g., upwardly from the deformable hinge 116 in the figure, while the lower locking arm 132 generally extends in the opposing direction, e.g., downwardly from the hinge 116 in the figure. As such, the deformable hinge 116 lies vertically between or intermediate the actuation and lower locking arms 130, 132 and defines a fulcrum point 138 about which each locking lever 114 may pivot.

[0042] In Figs 12 and 13, the lower locking arm 132 includes a locking wedge 136 defining a lead angle β and a locking angle θ. The lead angle β is defined by the incline of a guide surface 136 _G of the locking wedge 136 relative to the Z axis (or in the event that the guide surface is not linear, than the angle between the planes formed at the various points of contact on the guide surface and the Z axis. The locking angle θ is defined by the incline of a retention surface 136 _R of the locking wedge 136 relative to the R axis. In one embodiment, the lead angle β is greater than about 8 degrees relative to the Z-axis and more preferably greater than 10 degrees. In one preferred embodiment, the lead angle lies within a range between about 11 degrees and 21 degrees. The locking angle θ is between 0 degrees to about 45 degrees relative to the radial Ry, although it is preferable that the angle line within a range that is greater than 0 degrees and less than 45 degrees. In one embodiment, the locking angle is between about 5 degrees to about 10 degrees.

[0043] Referring to Figs. 10, 13, and 14, in the illustrated embodiment, a pair of locking levers 114 are disposed about the periphery or circumference of the cap 112 (best seen in Fig. 10). Preferably, the levers 114 are spaced equiangularly about the

circumference e.g., one-hundred and eighty degrees apart, however, the levers 114 may be spaced in unequal increments depending upon the particular application. As will be explained in subsequent paragraphs, more than two locking levers may be employed, however the number of locking levers 114 will, generally, not exceed a total of five.

[0044] The locking levers 114 may have any desired shape. For example the locking levers 114 may have a shape in the circumferential direction that is either linear or arcuate depending upon the desired cap configuration. In Figs 10 and 14, a top view of a locking lever 114 shows the curvature or arcuate shape of the lever 114 as it compliments or conforms to the periphery of the cover 120 in the circumferential direction. When employed about a circular cap 112, each locking lever 114 include locking tabs that may have an arc length corresponding to an angle φ. In one embodiment, the angle φ will be 45 degrees or less. In another embodiment, the range is between about 30 to 40 degrees. In one preferred embodiment, the angle is about 37 degrees.

[0045] The attachment and detachment of the closure 110 to the container 104 is now described with reference to Figs. 8-14. The description is applicable to the specific embodiment shown in the figures, however, the fundamentals generally apply to the alternate embodiments as well. Initially, the closure 110 of the present invention is aligned with the opening 106 of the container 104 such that the lower locking arms 132 and ring member 122 are adjacent the container lip 108. The closure 110 then is pressed axially downwardly against the container lip 108 such that the guide surfaces 136Q of the locking wedges 136 ride over an external surface of the lip 108. The deformable hinge 116 facilitates displacement of the lower locking arms 132 of the levers 114 as each locking wedge 136 passes the container lip 108. More specifically, the axial displacement of the closure 110 effects radial displacement of the lower locking arms 132 until the vertex V of the wedge 136 passes the lower edge 108 _LE of the container lip 108. Once the vertex V of each wedge 136 passes the container lip 108, the deformable hinge 116 causes the locking wedges 136 to displace radially inwardly, i.e. toward the principle Z-axis of the container 104. More specifically, the elasticity of the deformable hinge 116 rotates the levers 114 to cause the locking wedges 136 to engage the container lip 108.

[0046] Disengagement of the closure 110 is effected by pressing the actuation arms 130 of the locking levers 114 radially inwardly (shown in dashed lines in Fig. 13) to pivot the lower locking arms 132 about the fulcrum 138, i.e., in the direction of arrow A. As such, the radially inward displacement of the actuation arms 130 causes the locking arms 132 to disengage from the container lip 108. Generally, this can be performed with the thumb and forefinger of the same hand, while the container 104 is held in the other hand. Finally, with the locking wedges 114 disengaged from the container lip 108, the closure 110 may be axially separated from the container 104.

[0047] The closure 110 of the present invention can be configured to provide an air- or fluid-tight seal while providing a positive lock for mitigating spillage, even when the container is inadvertently mishandled. The locking levers 114 operate to prevent axial separation and are preferably designed to produce an axial bias tending to more thoroughly and effectively seal the closure 110 to the container 104. That is, the locking wedges 136 each define a shallow locking angle θ (see Fig. 13) which, when combined with the elasticity of the deformable hinge, produce a compressive force on the sealing surfaces 124, 128. More specifically, the deformable hinge biases the locking wedge 136 into engagement with the container lip 108. The radial displacement of the locking wedge 136, i.e., towards the principle Z-axis, causes the retention surface 136R to produce a small axial displacement. As such, the shallow locking angle θ provides a mechanical advantage to magnify the effectiveness of the deformable hinge 116. The axial displacement produced by the retention surface 136 _R , in turn, increases the contact pressure on the mating surfaces 124, 128 and, consequently, the sealing effectiveness therebetween.

[0048] In addition to the retention surfaces 136 _R , the guide surfaces 136Q also facilitate engagement of the closure 110 without the requirement to align the sealing surfaces 124, 128 or actuate the locking levers 114 . That is, the relatively steep lead angle β of the guide surfaces 136 _G enables self-actuation of the locking lever 114. Thus, engagement of the closure 110 may be performed by one hand.

[0049] While the closure devices of the prior art are prone to disengage when a container is inadvertently mishandled, e.g., dropped or tightly grasped, the locking lever 114 of the inventive closure provides a positive lock to prevent detachment from the

container 104. Additionally, it is preferable that the ring member 122 be configured to project or extend axially past the hinge 116 as shown in Figure 13 to form a sealing ring. As such, the ring member 122 functions to align the closure with the lip 108 during engagement and to structurally augment the lip 108 to inhibit deformation of the lip 108. As discussed above, such deformation can lead to separation of the closure from the container 110 and spillage of the contents.

[0050] One benefit of the closure 110 shown in the illustrated embodiment is that it can be installed and removed by one hand, while the other grasps the container 104. That is, the locking levers 114 are spatially positioned to be actuated by the fingers of one hand. Preferably the size of the closure 110 is consistent with that of an average individual, i.e., commensurate with a person's hand size and finger reach.

[0051] The closure 110 of the present invention may be manufactured by conventional low-cost fabrication techniques, such as injection molding, and in the described embodiment, is manufactured from injection-molded thermoplastic. The injection molding process, preferably, employs polypropylene plastic to produce an integral structure. That is, the cap 112, locking lever 114, and deformable hinges 116 are fabricated as a unit to. form an uniform structure having substantially isotropic properties.

[0052] Various alternate embodiments of the invention are depicted in Figs 15 through 17. hi Fig. 15, three (3) locking levers 114 are spaced equiangularly about the periphery of the central cap 112. It will be appreciated that three fingers, working together, will be required to displace the upper actuation arms 130.

[0053] In Figs. 16 and 17, the closure 110 may include an opening 150 for dispensing the container contents. The opening 150 may be closed and sealed by a hinged cover plate 152 which may be integrally formed along the upper surface of the cap 112. While holding and dispensing a liquid, the closure 110 may include a vent 154 disposed through the cap 112 to facilitate fluid flow, i.e., to prevent a flow restricting vacuum within the container 104. Like the opening 150, a hinged vent plate 156 may be integrally formed to open and close the vent. Fig. 10 shows the hinged cover and vent plates 156. In this embodiment, the locking levers 114 are disposed on opposite sides of the hinged cover and

vent plates 152, 156 so as not to interfere with cover opening 150 or vent 154. Further, to ensure that the locking levers 114 are not inadvertently actuated, a pair of locking levers 114a, 114b may be employed on each side of the opening 150.

[0054] Further, a variety of other modifications to the embodiments will be apparent to those skilled in the art from the disclosure provided herein. Thus, the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.