Twist-open closure having inclined frangible membrane

A closure for a container having an opening includes a base cap and an overcap that form a sealed chamber adjacent the opening that is isolated from the contents of the container. The base cap includes an outer skirt having container-engaging structure, a cylindrical well, a frangible membrane connected to the well along an inclined line of weakness and by a hinge member. The hinge member includes a pocket extending downward adjacent lower and upper terminuses of the line of weakness. The overcap includes a body having gripping structure, an inner skirt received within and rotatably connected to the well, and a cutting member depending from a lower end of the inner skirt received within the pocket such that the cutting member extends below the upper terminus. The cutting member severs the line of weakness upon substantial rotation of the overcap with respect to the base cap. A method of using the closure is also disclosed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates, in general, to closures for containers and more particularly to twist-open closures having an inclined frangible membrane and methods for their use.

2. Description of Related Art

Closures designed to store a consumable separate from a liquid until use are known. For example, U.S. patent application Ser. No. 10/313,575 discloses a closure including a cap, a rotatable spout, piercing structure and a sealing foil that encases a consumable material such as a tablet. The piercing structure is adapted to pierce the sealing foil and bias the foil downwardly in order to facilitate the introduction of the tablet into the liquid of a container upon rotation of the spout relative to the cap.

While the above structure is quite effective to isolate the consumable material from the contents of the container until use, in some instances a discrete sealing foil may prove undesirable. An exemplar of a prior art closure, which does not require a discrete sealing foil, is International Application Publication No. WO 01/08996 to Yu, which publication shows a spin-opening type bottle cap for separating solute and solvent. Disadvantageously, such prior bottle caps may require a significant amount of force on the part of a user to initiate opening of the bottle cap. Furthermore, prior caps are often more complicated to manufacture. For example, as very precise alignment of parts is often necessary to assembly prior caps.

What is needed is a twist-open closure that overcomes the above and other disadvantages of known closures.

BRIEF SUMMARY OF THE INVENTION

In summary, one aspect of the present invention is directed to a closure for a container having an opening includes a base cap and an overcap that form a sealed chamber adjacent the opening, which chamber is isolated from the contents of the container. The base cap may include an outer skirt having container-engaging structure, a cylindrical well, a frangible membrane connected to the well along an inclined line of weakness and by a hinge member. The hinge member may include a pocket extending downward adjacent lower and upper terminuses of the line of weakness. The overcap may include a body having gripping structure, an inner skirt received within and rotatably connected to the well, and a cutting member depending from a lower end of the inner skirt received within the pocket such that the cutting member extends below the upper terminus. The cutting member preferably severs the line of weakness upon substantial rotation of the overcap with respect to the base cap.

The cutting member may be approximately one-eighth inch high. The cutting member may include an angled knife-edge. In one embodiment, relative rotation between the overcap and the base cap in excess of approximately 0-10° causes the cutting member to at least partially sever the line of weakness. The container-engaging structure may include container-engaging thread dimensioned and configured to cooperate with closure-engaging thread of the container. The closure may further include a tamper-evidencing base band frangibly connected to a lower end of the outer base cap skirt. The closure may further include a tamper-evidencing overcap band frangibly connected to a lower end of the overcap body and operably engaging tamper-evidencing structure on the base cap. The overcap band may include an inwardly-extending protrusion extending inwardly and operably engaging an outwardly-extending protrusion on the base cap. In one embodiment, relative rotation between the overcap and the base cap in excess of approximately 0-5° causes the overcap band to at least partially separate from the overcap body. A first amount of relative rotation between the overcap and the base cap may be required to at least partially separate the overcap band from the overcap body and a second amount of relative rotation may be required for the cutting member to at least partially sever the line of weakness in which the second amount may be greater than the first amount. The second amount may be approximately 2-10° greater than the first amount.

The base cap may include an annular groove and the overcap may include a locking structure rotatably received within the groove to axially lock the overcap to the base cap. The inner overcap skirt may include a sealing bead extending around the lower end of the inner overcap skirt in which the sealing bead engages an inner surface of the well to provide a seal between the base cap and the overcap.

The overcap may include a pushing member having a lower end positioned adjacent the cutting member wherein the pushing member engages the membrane and pushes the membrane open upon substantial rotation of the overcap with respect to the cap base. The closure may further include a rotation lock that engages upon full rotation of the overcap with respect to the base cap. Full rotation may be in the range of approximately 300-330°. Full rotation may be approximately 315°. The rotation lock may include an outwardly-directed lock recess on the base cap and an inwardly-extending lock projection extending inwardly from an inner surface of the overcap body. The rotation lock may be configured to produce an audible sound upon engagement of the lock projection into the lock recess.

The well and the inner overcap skirt may form a sealed chamber and the closure further may include a consumable material in the chamber. The consumable material may be a tablet.

The overcap may include an aperture and the closure may include a dust cap having a plug for sealing the aperture. The dust cap may include a tamper-evidencing dust-cap band frangibly connected to a lower end of the dust cap and operably engaging tamper-evidencing structure on the base cap.

The twist-open closure of the present invention has other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated in and form a part of this specification, and the following Detailed Description of the Invention, which together serve to explain the principles of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A closure30in accordance with the present invention is shown inFIG. 1. The illustrated closure can be used with a container of the type often used for bottled water, sport drinks and other flowable bottled substances. The closure of the present invention is particularly suited for use with containers having a liquid that is to be mixed with a consumable including, but not limited to, tablets, powders and liquids by the consumer at the time of consumption. In some aspects, the closure is similar to that disclosed by U.S. patent application Ser. No. 10/313,575, the entire content of which is incorporated herein by this reference.

The closure of the present invention generally includes a cap base31adapted for releasably engaging the container and an overcap32rotatably mounted on the cap base to form a chamber33therebetween (seeFIG. 4). The closure contains a consumable34(schematically illustrated as a tablet inFIG. 4) that may be mixed with, or otherwise introduced to the contents of the container to which closure is mounted when closure is initially opened.

Preferably, the cap base and the overcap are formed as monolithic thermoplastic members using various methods including, but not limited to, injection molding techniques well known in the art. The cap base and the overcap may be formed of various materials including, but not limited to, low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, polystyrene, and/or other suitable materials. Preferably the overcap is formed of a harder material than the cap base in order to facilitate cutting into the slanted membrane. For example, the overcap may be formed of a high-density polyethylene and the cap base may be formed of a low-density polyethylene.

In the illustrated embodiment, the cap base is generally dimensioned and configured to cooperate with a container having a tamper-evident neck finish of the type shown in U.S. Pat. No. 6,112,923 to Ma, the entire contents of which is incorporated herein by this reference. One should appreciate, however, that the cap base can be adapted to cooperate with other container neck finishes within the scope of the present invention. For example, a cap in accordance with the present invention can be adapted to cooperate with a container having a snap-on, screw-off cap neck finish of the type shown in U.S. Pat. No. 6,173,853 to Luch, the entire contents of which is incorporated herein by this reference. Alternatively, other cooperative closure-container retention structure, such as a simple snap engagement, can also be employed in accordance with the present invention.

The cap base includes a cap top35. Although the annular surfaces of the cap top illustrated inFIG. 1is planar, the cap top can alternatively have a frustoconical or other suitable shape. A base-cap outer skirt36depends downwardly from the cap top in a well-known manner. The base cap outer skirt includes vertically extending ribs37extending from an external surface thereof to provide a gripping surface for facilitating a user in gripping and turning the cap base to screw the closure on and off from a respective container. The cap skirt also includes a container-engaging member extending from an internal surface of the cap skirt. In the illustrated embodiment, the container-engaging member includes internal threads38. As noted above, the cap can be adapted for use with various container-neck finishes, in which case a different thread or snap fit configuration can be used. Preferably, a tamper-evident base band39is frangibly connected to a bottom portion of the cap skirt and is adapted to detachably engage the container in a well known manner, as described in the '923 Ma patent.

The base cap also includes a cylindrical well40and a frangible membrane41connected to and fluidly sealing the bottom of the well, as can be seen inFIG. 4. The membrane is connected to the well along an inclined line of weakness42and by a thickened-material hinge member43such that the membrane remains attached to the well by the hinge member even after the line of weakness has been separated, as described below. In one embodiment, the hinge member includes a pocket44that extends downwardly adjacent the lower terminus45and the upper terminus46of the line of weakness.

The overcap includes an overcap body47having gripping structure48, and an inner skirt49received within and in rotatable contact with the well. The overcap further includes a cutting-member50depending from a lower end51of the inner skirt received within the pocket such that the cutting member extends below the upper terminus and adjacent the lower terminus of the line of weakness. Preferably, the cutting member also extends into the pocket to a level that is slightly below the lower terminus in order to ensure that the cutting member severs the line of weakness and thus severs the connection between the frangible membrane and the well.

The line of weakness extends along a helical path thus providing the frangible membrane with a slanted or inclined configuration, as can be seen inFIG. 3andFIG. 4. Such a slanted-membrane configuration allows the cutting member to gradually cut into the line of weakness thus reducing the amount of twisting force necessary for a user to initiate cutting.

Preferably, the cutting member is approximately one-sixteenth to one-half inches high, and most preferably, approximately one-eighth inch high. One will appreciate that the actual height of the cutting member will vary depending upon the dimensions of the frangible membrane. In this regard, the cutting member is preferably slightly taller than the vertical distance between lower and upper termini of the line of weakness. The cutting member may include an angled knife-edge52in order to facilitate cutting along the line of weakness.

In one embodiment, the base cap includes an annular groove53and the overcap includes locking structure such as, but not limited to, a locking bead54rotatably received within the groove to axially lock the overcap to the base cap. Preferably, the inner overcap skirt includes a sealing bead55extending around the lower end of the inner overcap skirt and engages an inner surface56of the well in order to provide an effective seal between the base cap and the overcap. Such configuration facilitates isolation of the consumable or like item from the liquid or other contents of the container. One will appreciate that the seal may be fluid-tight, airtight and/or other suitable seal designed according to the package requirements. For example, the seal may be configured to provide an airtight seal if required to protect ingredients contained within the chamber from atmospheric moisture, air, oxygen or other ambient environment.

Turning now toFIG. 2andFIG. 4, the pocket of the hinge member extends in an arcuate manner along the peripheral edge of the frangible membrane. The pocket may extend approximately 5-180°, preferably approximately 5-90°, and more preferably approximately 30-60° along the peripheral edge of the frangible membrane. In the illustrated embodiment, extends approximately 45°. Such a circumferentially-extending configuration allows a certain amount of relative rotation between the overcap and the base cap before the cutting member cuts into the frangible membrane along the line of weakness. For example, in one embodiment, the relative rotation between the overcap and the base cap must exceed approximately 0-10° to cause the cutting member to at least partially sever the line of weakness.

As a user continues to rotate the overcap, the cutting member continues to cut along the line of weakness thus opening the chamber defined by the well to the interior and/or contents of the container to which the closure is mounted. In one embodiment, the overcap includes a pushing member57having a lower end positioned adjacent the cutting member. The pushing member engages the membrane and pushes the membrane open upon substantial rotation of the overcap with respect to the cap base, as shown inFIG. 7andFIG. 8. In this regard, the pushing member rides along the periphery of the membrane from the lower terminus to the upper terminus, contacting the membrane and biasing the membrane downwardly as shown inFIG. 10. For the purpose of the present invention, substantial rotation refers to the amount of rotation required for the cutting member to sever a sufficient portion of the line of weakness to allow the frangible membrane to fold or otherwise displace downwardly allowing a consumable or other item located within the well to fall downwardly into the interior and/or contents of the container.

In one embodiment, the overcap includes a tamper-evidencing overcap band1that is frangibly connected to a lower end2of the overcap body. The overcap band is dimensioned and configured to operably engage a tamper-evidencing structure3on the base cap. In one embodiment, the overcap band includes an inwardly-extending protrusion such as, but not limited to, the illustrated segmented bead4that operably engages the tamper-evidencing structure of the base cap. The inwardly-extending protrusion and the base-cap tamper-evidencing structure cooperate to prevent rotation of the overcap with respect to the base cap without breaking one or more overcap bridges5that frangibly connect the overcap band to the overcap body. Preferably, the tamper-evidencing structure includes one or more outwardly-extending protrusions, however, one will appreciate that other tamper-evidencing configurations may be utilized in accordance with the present invention including, but not limited to splines, ratchet teeth, and/or other suitable anti-rotation means. The overcap bridges are configured to fail upon relative rotation between the overcap and the base cap.

In one embodiment, relative rotation between the overcap and the base cap exceeding approximately 0-5° causes the overcap band to at least partially separate from the overcap body, however, one will appreciate that the actual amount of rotation may vary in accordance with the present invention. Preferably, a first amount of relative rotation between the overcap and the base cap required to initiate separation of the overcap band from the overcap body is less than the relative rotation that is required for the cutting member to initiate severance of the line of weakness. In particular, as a user twists the overcap relative to the cap base, the frangible bridges will fail before the cutting member initiates cutting of the frangible membrane thus providing a visual indication that someone may have tampered with the closure, and the container upon which it is mounted, even before the frangible membrane is damaged. In one embodiment, second amount is approximately 2-10° greater than the first amount, which is substantially equal to the angular distance between the knife-edge and the lower terminus.

In one embodiment, the closure further includes a rotation lock63that engages upon full rotation of the overcap with respect to the base cap. Preferably, full rotation is greater than approximately 180°, more preferably within the range of approximately 300-330°, and most preferably approximately 315°. The rotation lock includes an outwardly-directed lock recess64on the base cap and an inwardly-extending lock projection65extending inwardly from an inner surface of the overcap body. The rotation lock may be configured to produce an audible sound upon engagement of the lock projection into the lock recess.

The method of using the closure in accordance with the present invention can now be described. Closure30may be assembled prior to its application onto a container. In particular, the well of the base cap and/or the cylindrical skirt of the overcap may be provided with a consumable item. The base cap and overcap are then assembled by inserting the cylindrical skirt into the well such that the consumable item is located in the chamber formed between the cylindrical skirt and the well. The chamber is sealed from exterior of the closure and thus is also isolated from the contents of the container upon which the closure is mounted.

In operation and use, a user will hold the container and twist the overcap relative to the base cap and the container. Upon a first amount of relative rotation, the connecting bridges of the overcap band fail thus providing visual indication of tampering. With continued rotation of the overcap relative to the base cap, the cutting member begins to cut into and along the line of weakness thus partially separating the frangible membrane from the well and exposing the chamber, and the consumable therein, with the interior and contents of the container. Continued rotation of the overcap causes the pushing member to bias the membrane downwardly thus facilitating the introduction of the consumable item into the contents of the container. The user may continue rotating the overcap to the point of full rotation thereby activating the rotation lock. Namely, once full rotation is accomplished, the lock projection snaps into the lock recess thus providing the user with an audible click indicating that the closure chamber is fully opened. The configuration of the rotation lock discourages and/or prevents reverse relative rotation of the overcap with respect to the cap base thus ensuring that the pushing member prevents the frangible membrane from returning to its initial position.

Advantageously, the slanted-membrane configuration of the present invention allows for a closure that is relatively simple to manufacture. The overcap may simply be aligned and snapped onto the base cap without twisting. Also, the configuration of the present invention also provides for a compact design. As the closure does not require axial motion to pierce the membrane, the closure may have smaller axial dimensions and/or a lower profile.

In another embodiment of the present invention, closure30ais similar to closure30described above but includes a dust cap66as shown inFIG. 13throughFIG. 16. Like reference numerals have been used to describe like components of closure30and closure30a. In this embodiment, the overcap includes an aperture67which allows dispensing of the container contents once the frangible membrane has been opened. The dust cap including a plug68for sealing the aperture.

Preferably, the dust cap includes a tamper-evidencing dust-cap band69frangibly connected to a lower end of the dust cap and operably engages cooperating tamper-evidencing structure on the base cap. In operation and use, closure30ais used is substantially the same manner as closure30discussed above.

For convenience in explanation and accurate definition in the appended claims, the terms “up” or “upper”, “down” or “lower”, “inside” and “outside” are used to describe features of the present invention with reference to the positions of such features as displayed in the figures.

In many respects the modifications of the various figures resemble those of preceding modifications and the same reference numerals followed by subscript “a” designates corresponding parts.