The present invention generally relates to tampon pledgets and, more particularly, to tampon pledgets that expand in the vaginal canal in response to the absorption of body fluids.
In female placental mammals, particularly humans, the vagina is an elastic muscular canal that extends from the uterus inside the body to the vulva on the outside the body. The narrow lower neck of the uterus forms the cervix. The entrance to the vagina is known as the introitus and is located at the back end of the vulva.
Although there is wide anatomical variation, the average length of the canal from the introitus to the cervix is about 3 to 5 inches. The introitus is of a relatively small diameter, and the bottom two-thirds of the vagina is only slightly, if at all, wider than the introitus. The transverse (side-to-side) width in the bottom two-thirds portion is typically slightly larger than the front-to-back width, which is especially small. The vagina is widest in its upper one-third portion nearest the cervix. The elasticity of the walls of the canal that forms the vagina allows it to stretch as needed. When the vagina is in a relaxed state, the walls thereof typically collapse on each other but can be opened up slightly with minimal pressure.
From a biological perspective, the vagina provides a path for fluids to leave the body during the menstruation phase of the menstrual cycle. The menstrual cycle is a recurring cycle of physiological changes in females that is associated with reproductive fertility. The menstruation phase of the menstrual cycle involves the shedding of the uterine lining. During this shedding, tissue and blood is exuded from the uterus.
In modern cultures, disposable absorbent devices have been used for the capture and absorption of material, particularly the blood, exuded during the menstruation phase. These devices include external-use sanitary towels or napkins and internal-use devices such as tampon pledgets. Other devices such as internally-worn cups are also known but not in wide use today.
Tampon pledgets generally comprise non-woven webs of absorbent materials such as rayon, cotton, combinations of the foregoing, and/or other materials in fiber form. These webs are typically stacked such the interfacial areas thereof are bonded together. The stacked and bonded webs are then folded, pleated, and/or rolled to approximate the desired geometry, which is typically a generally cylindrical shape. One end of a string is incorporated into the web material, which is then compressed to a final shape. The string functions as a means of withdrawing the tampon pledget from the vagina after the useful life of the tampon pledget. A coverstock may be located over the compressed absorbent materials to maintain the cylindrical shape and/or to provide increased comfort during the insertion and removal of the tampon pledget. The tampon pledgets are then optionally inserted into a cardboard or plastic applicator device and packaged.
When inserted into the vagina and expanded, such conventional tampon pledgets are generally sufficient to accommodate differences in menstrual flow patterns for the vast majority of women. However, the differences in anatomical structure of women oftentimes results in a less than optimal conformance to the vaginal shape. When the tampon pledget does not conform to the vaginal shape, the likelihood of flow of body fluids from the cervix, around the tampon, and to the introitus is increased. Many conventional tampon pledgets generally conform to the shape of the vagina. However, the shapes of such pledgets are determined and attained prior to contact of the material by the body fluids.
Based on the foregoing, it is an object of the present invention to provide a tampon pledget that expands when contacted by body fluids to more closely approximate the shape of the vagina to prevent or at least minimize the likelihood of leakage of body fluids from the vagina.
In one aspect, the present invention resides in a tampon pledget having an absorbent mass of material and a withdrawal string located at one end thereof. The tampon pledget is initially cylindrical in shape. During use and upon contact with menses or other body fluids, the tampon pledget expands to take on a geometric configuration that approximates the shape and configuration of the vagina into which the tampon pledget is inserted. This expansion results largely from the density distribution of the materials utilized to form the tampon pledget. Preferably, the tampon pledget expands to form an hourglass-shaped member that provides suitable contact with the vagina walls. The upper portion of the hourglass shape absorbs the bulk of the menses or other body fluid, while the middle portion and the lower portion proximate the introitus also contact the walls of the vaginal cavity to absorb any menses or other fluid that may have bypassed the upper portion.
In another aspect, the present invention resides in an anthroprometrically expandable tampon pledget having an absorbent mass of material that is defined by a first end having a first density, a second end having a second density, and a portion intermediate the first and second ends. This intermediate portion has a third density that is different from at least one of the first density and the second density. The differences in densities allow the material of the mass to expand at different rates upon being contacted by body fluids, thereby allowing the tampon pledget to conform to the shape of a vaginal cavity. The tampon pledget also has means for withdrawing the tampon pledget from the vaginal cavity (such as a string). The absorbent mass of material is cylindrical in shape.
In another aspect, the present invention resides in a method of making an expandable tampon pledget. This method includes the steps of providing at least one absorbent material, attaching a string thereto, and compressing the absorbent material into a final cylindrical shape such that a density gradient is realized over a length of the compressed absorbent material. A density gradient defined along the length of the tampon pledget allows it to anthroprometrically expand to the shape of a vaginal cavity into which it is inserted upon contact with body fluid.
Although the conformance of the shape of the tampon pledget to the vaginal cavity allows for the absorption of fluid while minimizing leaking to the introitus, several other advantages will become apparent. First, such a configuration provides optimal comfort to the user. In particular, because the tampon pledget expands to contact the walls of the vagina, it exerts pressure in the radial directions, thereby allowing the tampon pledget to be securely held in the vaginal canal. This provides an improved level of comfort to the user, particularly in instances in which the user is physically active.
Second, the cylindrical shape of the tampon pledget is relatively inexpensive and easy to manufacture. Tooling apparatus and manufacturing processes, particularly those related to compressing the pledget material into the pre-expanded shape, can be simple in design.
Third, because the pledgets of the present invention are initially cylindrical rather than curved or serpentine in shape, only a minimal amount of force is required to eject these tampon pledgets from convention tampon pledget applicators (which are typically cardboard or plastic). Thus, the tampon pledgets of the present invention may be used with existing applicators, and no new tooling or design considerations are necessary.
These and other advantages of the present invention will become apparent to those of skill in the art from the following description of the preferred embodiments.
As shown in
In its initial form (
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The webs 24 are arranged such that about one third of the absorbent mass 12 proximate the insertion end 16 of the finished pledget 10 has an initial predetermined density. The webs 24 are also arranged such that about one third of the absorbent mass 12 proximate the withdrawal end 18 of the finished pledget 10 also has an initial predetermined density. These two densities, which may or may not be the same, are based on the mass of absorbent material per unit volume and at least one of the particular geometry of the web material used, the method of constructing the pledget 10, the application of pressure to the absorbent mass 12 to form it to the cylindrical shape, the direction and duration of pressure application, and ambient temperature.
In one embodiment as shown in
In another embodiment as shown in
The present invention is not limited to the combination of webs of varying sizes, as webs of varying shapes and weights may also be used to form the tampon pledget of the present invention.
In any embodiment, the webs can be produced by combing or carding using a suitable combing or carding device to produce a matte of non-woven fibers. Fibers in this matte can be oriented in a particular direction by, for example, a carding machine and aligned. In the alternative, the fibers can be randomly arranged. By varying the number, distribution, and orientation of absorbing fibers relative to non-absorbing fibers, the density of the matte can be adjusted.
The fibers can be bound together using any of a variety of techniques. For example, the fibers can be bound using barbed needles in a needletacking process; they can be bound chemically using adhesives, water-dispersible binders, or the like; they can be bound thermally using high temperatures; or they can be bound using a hydroentangling technique using high-pressure water jets. Irrespective of the technique used, the density of the matte can be adjusted during the particular technique. The binding generally prevents the sloughing of fibers in the woman's vagina. In the alternative, the fibers in the matte can be left unbound, and a second web of non-woven material can be used as a covering to prevent the sloughing of unbound fibers.
Once the matte has been finally formed, a portion of material is cut therefrom, wound into the approximate shape of a tampon, and cut to the size desired for a specific absorbency range. The material can be rolled up using mechanical means in which the material is wound on itself, or it can be folded into a desired shape (e.g., a “W” shape or the like) using folding rams. Typically, after either rolling or folding, the tampon is compressed into a self-sustaining cylindrical form. In addition to compressive forces, temperature and moisture content may be adjusted to provide the desired cylindrical form. The density of the tampon can also be adjusted by applying compressive forces of differing amounts of pressure. Once in the cylindrical form, the tampon can be combined with a tampon applicator.
Referring now to
Before the absorbent mass 12 is compressed, a top third portion 30 thereof has a greater initial mass and volume of absorbent material than does a middle third portion 32. When the absorbent mass 12 is compressed (
After compression in which the top third portion 30 and the bottom third portion 34 are compressed to correspond in cross sectional geometry to the middle third portion 32, the density varies along the length of the pledget 10 to produce a lengthwise density gradient dL. This lengthwise density gradient dL enables different portions of the pledget 10 to absorb fluid at different rates and therefore to expand at different rates. In particular, the denser top third portion 30 has a greater potential porosity than the middle third portion 32 and therefore has the potential to expand to a volume that is greater than the volume of the middle third portion 32. The bottom third portion 34, which also includes more tightly compressed and therefore denser absorbent material, expands in a manner similar to the top third portion 30.
In embodiments in which web materials for the top third portion 30 and the bottom third portion 34 differ from the material of the first web (shown as 24a in
Irrespective of whether or not the pledget 10 includes a radial density gradient dR, the geometry of the web material(s), the particular method of construction of the pledget, the application of pressure, the directions (radial and/or axial) of pressure application, the duration of pressure application, and the temperature are all factors in the determination of the ability of the pledget to absorb menses or other body fluids. Collectively, these factors are used to define a density profile of the pledget 10.
Once the absorbent mass 12 is compressed into its desired cylindrical form, the coverstock, if desired, can then be located thereover.
Referring back to
The actual preferred anthroprometric geometry and density profile of the pledget 10 during use depends on several factors. Thus, the particular embodiments of the pledget 10 described herein are not limited to those shown. Factors that may contribute to the anthroprometric geometry of the manufactured pledget 10 and its density profile during use include, but are not limited to, the geometry of the particular vagina in which the pledget is inserted, the absorbency of the material used to construct the pledget, the need for improved leakage protection such as bypass protection, and the need for comfort during the insertion, wearing, and removal of the pledget. Thus, the precise quantitative parameters for optimum geometries and densities can vary. More specifically, the precise quantitative parameters can differ based on whether the pledget 10 is intended for use by, for example, younger women, older women, women who have given birth, or active women.
Referring now to
Referring now to
Based on the foregoing, actual tampon design and geometry (e.g., density profile, initial tampon shape, and the like) suggest that changes to the design and geometry can affect expansion characteristics. Thus, such data supports the fact that the tampon pledgets of the present invention expand approximately into hourglass shapes, as shown in
As is shown in
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Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the appended claims.