The present invention relates generally to tampon applicators.
Vaginal tampons are disposable absorbent articles sized and shaped (e.g., cylindrical) for insertion into a women's vaginal canal for absorption of body fluids generally discharged during the woman's menstrual period. Insertion of the tampon into the vaginal canal is commonly achieved using a tampon applicator that comes initially assembled with the tampon. The applicator, which is often made of plastic or cardboard, is disposable. Thus, after the applicator has been used to insert the tampon into the user's vaginal canal the applicator is discarded.
Tampon applicators are typically of a two-piece construction, including a barrel in which the tampon is initially housed and a plunger moveable telescopically relative to the barrel to push the tampon out of the barrel and into the vaginal canal. The barrel has a tip that generally retains the tampon within the barrel until pushed through the tip by the plunger. In normal use, the applicator and more particularly the barrel of the applicator is held by the user by gripping one portion of the barrel (e.g., toward the trailing or plunger end of the barrel) and inserting the barrel, tip end first, into the vaginal canal. The barrel is pushed partially into the canal so that a portion (e.g., toward the leading or exit end of the tampon barrel) is disposed within the vaginal canal and is contact with the walls lining the canal. The plunger is then used to push the tampon out through the tip of the barrel and into the canal. The plunger and barrel are then removed from the vaginal canal, leaving the tampon in place.
In such use, the barrel (and plunger) of the applicator comes into contact with different body parts and/or skin regions of the user, such as the tip and part of the barrel contacting the walls lining the vaginal canal, while the user's finger(s) contact the barrel (and plunger) to grip and hold the barrel and to operate the plunger. The ability of the user to have a secure grip on the applicator while allowing the applicator to comfortably slide into and out of the vaginal canal is thus an important factor in acceptance of the applicator.
There is need, therefore, for a tampon applicator that provides a soft feeling, increased comfort and secure handling to the user.
In one aspect, a tampon applicator generally comprises an elongated barrel having an interior chamber for housing a tampon therein, an outer end and an inner end spaced longitudinally from the outer end. A plunger extends into the barrel at the outer end thereof and is moveable relative to the barrel to expel the tampon from the barrel at the inner end of the barrel. The barrel has at least two petals each having a base and extending longitudinally of the barrel to a tip of the petal wherein the petal tips define the longitudinal inner end of the barrel. The petals are configurable relative to each other and to the barrel from a closed configuration in which the petals generally close the inner end of the barrel and an opened position in which the petals are moved generally transversely outward to form an exit opening at the inner end of the barrel upon movement of the plunger to expel the tampon from the barrel at its inner end. Each petal has a length from its base to its tip, and the barrel has a cross-sectional dimension at the bases of the petals. A ratio of the length of the petal to the cross-sectional dimension of the barrel at the bases of the petals is in the range of about 1.0 to about 2.0.
In another aspect, a tampon applicator generally comprises an elongated barrel having an interior chamber for housing a tampon therein, an outer end and an inner end spaced longitudinally from the outer end. A plunger extends into the barrel at the outer end thereof and is moveable relative to the barrel to expel the tampon from the barrel at the inner end of the barrel. The barrel has a guide channel extending longitudinally therein adjacent the outer end of the barrel. The plunger extends through the guide channel into the interior chamber of the barrel. The guide channel has a cross-sectional dimension sized for a close fit relationship of the plunger in the guide channel. The guide channel further has a length, with a ratio of the length of the guide channel to the cross-sectional dimension thereof being in the range of about 1.0 to about 2.0.
In yet another aspect, a tampon applicator generally comprises an elongated barrel having an interior chamber for housing a tampon therein, an outer end, an inner end spaced longitudinally from the outer end, a grip region generally adjacent the outer end of the barrel, a tip region generally adjacent the inner end of the barrel, a central region extending longitudinally between the grip region and the tip region, and an outer surface. A plunger extends into the barrel at the outer end thereof and is moveable relative to the barrel to expel the tampon from the barrel at the inner end of the barrel. The outer surface of the barrel at the grip region has at least one of a different color and a different coefficient of friction than the central region of the barrel.
Other objects and features will be in part apparent and in part pointed out hereinafter.
Corresponding reference characters indicate corresponding parts throughout the drawings.
Referring now to the drawings and in particular to
The tampon applicator 21 has a longitudinal axis X, with the barrel 23 and plunger 27 being in coaxial relationship with each other on this axis. The plunger 27 is thus moveable telescopically along the longitudinal axis X from an extended position as illustrated in
The barrel 23 of the tampon applicator 21 is suitably sized and shaped for housing the tampon 25 within an interior chamber 33 (
With particular reference to
In one particularly suitable embodiment as illustrated in
Such a configuration allows the petals 51 to be bent inward to their closed configuration closer to the tips 57 of the petals, such as approximately the longitudinally outer one-third of each petal, as opposed to being bent nearer to or at their bases 55. This provides a softer and more flexible feel to the petals 51 in their closed configuration and also facilitates the formation of a gap 59 (
In another embodiment, to further facilitate a more soft and flexible feel and appearance at the tip region 45, the petals 51 are configured to have a lower stiffness (i.e., resistance to bending) than the central region 43 of the barrel. More suitably, the petals 51 may be formed to have a thickness that is less than the thickness of the barrel 23 at the central region 43 to effect a lower stiffness. For example, the petals may have a thickness in the range of about 0.2 mm to about 0.8 mm while at the central region 43 the barrel may have a thickness of about 0.4 mm to about 1.2 mm. The reduced thickness of the petals 51 allows the petals to be more flexible and pliable to provide a soft, flexible feel and appearance. It is understood, however, that the thickness of the petals 51 and/or the central region 43 of the barrel 23 may be other than as set forth above.
With reference back to
In one particularly suitable embodiment, the guide channel 63 has a length Lg sufficient to stably retain the plunger 27 coaxial with the barrel 23, i.e., to inhibit skewing of the plunger relative to the barrel as the plunger is pushed into the interior chamber 33 of the barrel to expel the tampon. For example, the length Lg of the guide channel 63 may suitably be in the range of about 5 mm to about 25 mm, more suitably in the range of about 12 mm to about 22 mm, and even more suitably about 15 mm to about 20 mm. As another example, the guide channel 63 of the applicator barrel 23 illustrated in
In another embodiment, a ratio of the guide channel 63 length Lg to the inner diameter of the barrel 23 segment that defines the guide channel is suitably in the range of about 1 to about 5, more suitably about 2 to about 4 and even more suitably about 3 to about 3.5. It is understood, however, that the inner diameter of the barrel 23 at the guide channel 63, and/or the guide channel length Lg, may be other than as set forth above without departing from the scope of this invention.
The plunger 27 is elongated and in the illustrated embodiment is suitably hollow (
In accordance with one embodiment, the barrel 23 is constructed such that the outer surface of the barrel at least at the central region 43 thereof, and more suitably at both the central region and the tip region 45 of the barrel, has a relatively low coefficient of friction to facilitate comfortable insertion of the barrel into the vaginal canal and removal therefrom. The barrel 23 is additionally constructed such that the outer surface of the barrel at its grip region 41 has a coefficient of friction that is substantially greater than the coefficient of friction at the central region 43 and tip region 45 of the barrel to facilitate gripping of the barrel while still providing a comfortable engagement between the outer surface of the barrel and the vaginal canal. Still more suitably, the barrel 23 is constructed to have a relatively soft feel and appearance while also providing the coefficient of friction differential between the grip region 41 and the central and tip regions 43, 45 of the barrel.
Generally speaking, frictional forces occur between any two contacting bodies where there are forces tending to slide one of the bodies relative to the other. The frictional forces act parallel to the contacting surfaces and opposite the forces tending to cause sliding between the bodies. Further, the frictional forces are proportional to normal forces on the bodies and to the tendency of the bodies to grip each other.
As used herein, the coefficient of friction is the ratio of the frictional force between the bodies to the normal force between the bodies. The coefficient of friction is different between bodies at rest and bodies moving relative to each other. In general, two bodies contacting one another, but not moving relative to one another, will exhibit greater frictional resistance to motion than bodies that are moving relative to one another. Hence, a static coefficient of friction (i.e., a coefficient of friction between bodies which are not moving relative to each other) may but need not necessarily be somewhat greater than a dynamic coefficient of friction (i.e., a coefficient of friction between bodies which are moving relative to each other). Larger coefficients of friction correspond to larger amounts of friction between bodies, while smaller frictional coefficients correspond to smaller amounts of friction. As used further herein, the term coefficient of friction refers to at least one of a static coefficient friction and a dynamic coefficient of friction. In particularly suitable embodiments, the coefficient of friction differential described previously is present for both static and dynamic coefficients of friction.
As one example, the barrel 23 according to one embodiment may be suitably constructed of at least two materials that differ in at least one characteristic. More suitably, in one embodiment the barrel is constructed of a first material that comprises the tip region 45, central region 43 and an underlying portion of the grip region 41, and a second material that comprises the overlying portion of the grip region. For example, the barrel 23 may be constructed along its full length (i.e., at the tip region 45, central region 43 and grip region 41) of a polymeric first or core layer 81 comprising a polyolefin such as, without limitation, polypropylene, polyethylene, low density polyethylene, high density polyethylene, linear low density polyethylene, near low density polyethylene, polyethylene terephthalate PET), nylon, polystyrene, polyvinyl chloride, polymethyl methacrylate, polyolefin elastomer, copolymers of alfa-olefines, and combinations thereof. More suitably the first or core layer 81 of the barrel 23 is formed of a low density polyethylene or a polymeric blend that includes low density polyethylene, such as a combination of low density polyethylene and at least one of linear low density polyethylene or a high density polyethylene.
One or more additives may be added to the polymeric first layer 81 of the barrel 23 (prior to molding) to enhance the slip characteristic (e.g., to provide a low coefficient of friction) of the barrel outer surface at least at the central region 43 of the barrel and more suitably at the central region and tip region 45 of the barrel. For example, suitable such additives include without limitation erucamide, demethicone, oleamide, fatty acid amide and combinations thereof. It is understood that other additives may used to provide enhanced slip characteristics to the barrel 23 outer surface without departing from the scope of this invention. In other embodiments the barrel 23 may instead, or additionally, be coated with a friction reducing, or slip agent such as, without limitation, wax, polyethylene, silicone, cellophane, clay and combinations thereof. In still other suitable embodiments the barrel 23 may comprise a polymer blend melted together and co-extruded to provide a low coefficient of friction.
In the illustrated embodiment, the barrel 23 is further constructed so that the barrel outer surface at the tip region 45 has a lower coefficient of friction than at the central region 43 of the barrel to facilitate easier insertion of the barrel, inner end first, into the vaginal canal. This is particularly useful on days which a period is relatively light. For example, the outer surface of the barrel 23 at the tip region 45 may be configured to have a substantially lower surface roughness than at the central region 43 of the barrel, and more suitably the tip region may be substantially smooth or polished to reduce the coefficient of friction of the tip region relative to that of the central region. As a particular example, the surface roughness (which provides a tactile perception to the user) of the central region 43 of the barrel may have a surface roughness of less than or equal to about 36 and is more suitably about 27 in accordance with VDI Richtlinie [Standard] 3400. VDI Richtlinie 3400 has the German title: “Electroerosive Bearbeitung, Begriffe, Verfahren, Anwendung” [Electrical Discharge Machining, Definitions, Process, Application], published by the Verein Deutscher Ingenieure [Association of German Engineers] in June 1975.
In another embodiment, the first or core layer 81 is constructed of at least two different but generally compatible materials (e.g., so that the barrel 23 is comprised of at least three materials—including the material from which the grip region 41 is constructed). In one particular such embodiment, the central region 43 and the tip region 45 of the barrel 23 are of different materials. The material from which the central region 43 is formed may also form an underlying layer of the grip region 41 and a third material forms an overlying or outer layer of the grip region. As an example, one suitable process for making the first or core layer 81 of at least two different materials as described above is referred to as a coinjection process and more particularly a sequential coinjection process. Such injection processes are known to those skilled in the art for molding together two compatible polymer melts.
In a sequential coinjection process, the material injected first (e.g., the material from which the tip region 45 is formed) flows to the wall near the entrance to the mold, and the second material (e.g., the material from which the central region 43—and underlying portion of the grip region 41 is formed) then enters the mold and continues to flow in the center of the channel and fan out to the wall further down the part. In this way the far end of the part, e.g., the tip region 45, can be comprised solely of the first material, while the portion of the barrel 23 forming the grip region 41 and central region 43, will contain the stiffer second material. To obtain stable and uniform skin layer thickness, it is preferred that the first material, have a lower viscosity than the second material. Having a lower viscosity ratio for the first material compared to the second material will also help the first material to be packed into the tip region 45.
One benefit of using sequential coinjection is that it provides more control over the composition of the part. The relative amounts of soft polymer (for the tip region 45) and stiffer polymer (for the central region 43) can be varied to control the flexibility/stiffness balance of the part. For example, a larger fraction of stiff polymer can be used to increase the overall stiffness of the part as compared to two-shot or multishot injection processes, in which the amounts of each region are fixed by the mold dimensions, or compared to single injection processes where the entire part is the same composition. Sequential coinjection also provides a seamless transition between regions, because there is no interface between materials on the surface of the part.
In other embodiments, the tip region 45 of the barrel 23 may instead, or additionally be coated with a friction reducing agent so that the outer surface of the barrel at the tip region has a lower coefficient of friction than that of the central region of the barrel. Providing a surface roughness differential between the tip region 45 and the central region 43 also serves as a visual indicator of the reduced friction coefficient at the tip region.
The grip region 41 is suitably constructed of a second or skin layer 83 applied over the first or core layer 81 along a longitudinal segment of the barrel 23 generally at the grip region thereof. In one particularly suitable embodiment, the second, or skin layer 83 forming the grip region 41 may comprise a thermoplastic elastomer (TPE) to provide the grip region with a soft, relatively rubbery feel that has a higher coefficient of friction than the first, or core layer 81 that defines the outer surface of at least the central region 43 of the barrel 23. It is understood, however, that other suitable materials may be used as the second, or skin layer 83 to provide a higher coefficient of friction to the grip region 41 without departing from the scope of this invention.
In other embodiments, the central region 43 and the grip region 41 may also be of different colors, which as used herein includes different hues as well as different shades of the same color as long as the different colors are visually perceptible by a human adult having 20/20 vision. Such a color change provides a visual cue to the user of a characteristic difference between the central region 43 and the tip region 45.
In the illustrated embodiment of
It is understood that the visual indicator 93 may be formed other than integrally with the barrel 23 during initial molding of the barrel, such as by imprinting the visual indicator on the barrel at the grip region (e.g., a textual message or a suitable image) without departing from the scope of this invention. It is also understood that a visual indicator 91 (other than the different material and/or color of the second or skin layer 83) may be omitted from the grip region 41.
The applicator plunger 27 is, in one particularly suitable embodiment, constructed of the same material (e.g., polymer or polymer blend) as at least the first layer 81 (
Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.
When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above products without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
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