Compressed Tampon With Tapered Tip

Abstract

An absorbent tampon made from an elongate rectangular pledget compressed to substantially cylindrical form with a tapered generally conical forward end, in which the conical tip has been formed in a manner to provide it with only a slightly lower density than the major cylindrical portion of the tampon, and to provide a section of the tampon taken at the base of said conical tip which is of slightly higher density than said major cylindrical portion. The method for making such a tampon is also disclosed. In this method the improved conical tip is formed without removing or cutting out material from the forward end of the starting pledget or the resulting tampon.

Description

BACKGROUND OF THE INVENTION

In the prior art there are a large number of patents directed to compressed cylindrical tampons having a generally conical, tapered or rounded tip, and to the method of forming such tampons. The principal purpose of the tapered tip is to allow easier insertion. Representative patents from among this large group include U.S. Pat. No. 2,386,590 to Calhoun; U.S. Pat. No. 2,499,414 to Rabell; U.S. Pat. No. 2,706,986 to Carrier; U.S. Pat. No. 2,926,394 to Bletzinger et al.; U.S. Pat. No. 3,204,635 to Voss et al.; U.S. Pat. No. 3,397,695 to Voss; and Canadian Pat. No. 828,402 to Voss.

In the patented teachings, the conical tip is obtained either by compressing various pledgets of predetermined size and shape directly into the desired configuration, or by cutting out and/or removing a portion of the fibrous material in the tip before or after shaping.

When compressed directly, as taught in several of the patents, the resulting tip portion often becomes too hard and dense, as a result of the excess material present in the starting pledget, and the necessity for therefore compressing the tip portion more than the remaining portion to obtain the desired shape. While insertion is made easier because of the resulting firmness of the tip, the ability of the tip portion to expand and absorb fluid is thereby inhibited because the elastic limit of the fiber material is often exceeded.

When portions of the fibrous mass are removed from the forward end of the pledget before compressing to permit easier compressive forming of a conical tip, as taught in other patents, the tip absorbs fluid satisfactorily but is softer than the remaining part of the tampon due to the reduced amount of material therein and tends to collapse during insertion, unless used with a supplementary insertion aiding device. It was also found that the fibers in these less dense tips do not expand to fill the cavity as well as other portions of the tampon, apparently because of the reduction in mass in the tip area.

The present invention overcomes these difficulties by providing a conical tip of only slightly less density than the other portions of the tampon and by providing a structure which aids in expanding the conical tip more rapidly upon absorbing enough fluid to relieve the compression forces and permit expansion.

SUMMARY OF THE INVENTION

In accordance with this invention a compressed cylindrical tampon with a generally conical forward end is formed from an elongate rectangular pledget without the prior removal or cutting away of portions of the material before compressing the pledget to final shape.

In providing this improved tampon, the forward end wall of the starting rectangular pledget is depressed to form a V-shaped indentation therein during a precompression step. This V-shaped indentation is retained while the precompressed pledget is pressed sideways into substantially cylindrical form. The resulting cylinder with the V-indentation retained in the forward end wall is then compressed longitudinally while the V-indented forward portion is simultaneously shaped into the form of a generally conical tip.

The method of forming may be described as follows:

A starting rectangular pledget of predetermined size is first confined in a die having a cavity of somewhat kidney-shaped cross-section which is transversely contractible to cylindrical form. An upper V-shaped forming tool, or wedge, is then employed in cooperation with a lower compressing tool, or plunger, to partially precompress the pledget longitudinally within the die cavity. The point of the V-shaped, chisel-like, tool is disposed centrally of the forward wall of the pledget and depresses the mid-point of the forward wall portion of the pledget sufficiently to form a V-shaped indentation therein, while the corners of the pledget defining each end of the forward wall remain substantially unaffected. The die is then partially closed sideways to start forming the pledget into its final cylindrical shape. This partial transverse compression serves to maintain the V-shaped indentation in the forward end of the pledget while the V-shaped forming tool and a cooperating longitudinal compressing plunger are subsequently retracted. After the V-shaped tool and compressing plunger are withdrawn, the die is completely closed transversely to form the pledget into its main cylindrical configuration. The final step is to again longitudinally compress the cylindrically formed pledget, this time using as the top compressing plunger a tool having a conical cavity which shapes the V-indented forward portion of the pledget into a generally conical form by urging the corners of the forward end wall together to close the previously formed V-indentation and compress the tips of the corners into a self-sustaining conical shape.

The final result is a tampon having only slightly less density in the conical tip portion as compared with the density of the main cylindrical portion with a slightly higher density only in a section taken approximately at the base of the conical tip. It will be seen that the forward wall area of the tampon in this structure is medially folded on itself to define two adjacent conical half sections in the finished tampon tip. This folded wall portion also provides an outwardly biased hinge at the base of the conical tip in the finished tampon which aids in more positively expanding the forward end portion of the tampon when the compression is relieved by the absorption of fluid.

Other features and advantages of the invention will become apparent by reference to the following specification and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a suitable starting pledget as it appears before forming it into the compressed tampon shape.

FIG. 1a is a perspective view of one form of a prior art starting pledget.

FIG. 2 is a perspective representation of a compressed tampon made in accordance with this invention.

FIG. 3 is a partial sectional view of the tampon pledget as it is first positioned in the transverse compressing dies.

FIG. 4 is a partial sectional view through the die portion only of FIG. 3 showing the initial position of the die cavity, its somewhat kidney-shaped cross section, and the cooperative contractile arrangement of the dies before any transverse compression takes place.

FIG. 5 is a partial sectional view similar to FIG. 3 showing a preliminary longitudinal precompression step.

FIG. 6 is a partial sectional view of the next step in longitudinal precompression.

FIG. 7 is a partial sectional view of the preliminary transverse compression step.

FIG. 8 is a partial sectional view showing the longitudinal expansion of the tampon after the precompression tools are retracted.

FIG. 9 is a partial sectional view showing the last transverse compression step.

FIG. 10 is a partial sectional view through the die portion only of FIG. 9 showing the position of the dies after they have been fully contracted in the last transverse compression step.

FIG. 11 is a partial sectional view showing the final longitudinal and tip shaping compression step.

FIG. 12 is a partial sectional view showing the longitudinal re-expansion of the compressed tampon which occurs after the tip-shaping tool is retracted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The completed tampon with a generally conical tip as shown in FIG. 2 is made from a rectangular starting pledget of substantially the shape and comparative size shown in FIG. 1. It comprises a main cylindrical body portion 15 with a substantially conical forward end portion 16 and a withdrawal string 17 attached to the rear end portion. The pledget 10 comprises any of the well known absorbent materials which are capable of being compressed into the self-sustaining form shown in FIG. 2 and capable of reexpanding when wetted to a size approaching the size of the original starting pledget. Pledget 10 is comprised of upper wall 5, lower wall 6, side walls 7 and 8, forward end wall 12 and rear end wall 13.

The steps used to compress the starting pledget to its finished shape and size may best be described by reference to FIGS. 3 through 12.

Starting pledget 10 is first placed within a pair of cooperating dies 18 and 19 which are movable transversely in the directions indicated by arrows 20 and 21 to change cross-sectional opening 22 from generally kidney-shaped to circular form during the compressing process, and are employed to compress pledget 10 to substantially cylindrical shape.

In FIG. 5, a V-shaped, chisel-like, forming tool 23 is introduced in the top of cavity 22 to first depress indentation 25 into the midpoint of the forward wall 12 of pledget 10, while the rear wall 13 is supported by plunger 24, which is introduced at the bottom of cavity 22.

In FIG. 6, pledget 10 is shown as being compressed longitudinally by movement of tool 23 and plunger 24, toward each other while pledget 10 remains confined between dies 18 and 19, which are effective in preventing transverse expansion during this step. This compression step causes a deepening of indentation 25 in forward end wall 12 of pledget 10 by V-shaped tool 23.

In the next step, FIG. 7, dies 18 and 19 are partially closed to partially precompress pledget 10 transversely while V-shaped tool 23 and plunger 24 remain in the position obtained in FIG. 6. This step also forms the side walls of the pledget into semi-cylindrical configuration. V-shaped tool 23 and plunger 24 are then retracted.

FIG. 8 shows the upper V-shaped tool and lower plunger retracted while dies 18 and 19 remain in their partially closed position. The pledget is thus maintained in its partial transversely compressed condition but is free to partially reexpand longitudinally. Even though there is some longitudinal reexpansion of the pledget 10, upon retraction of tool 23 and plunger 24, the transverse forces exerted against the side walls of the pledget by the dies 18 and 19 serve to retain V notch 25 in the forward wall of the pledget.

In the next step, FIG. 9, the dies 18 and 19 are fully closed transversely so that opening 22, FIG. 10, is reduced to a substantially circular cross-section. This compresses pledget 10 to a substantially cylindrical form and notch 25 now is almost completely closed so that a substantial portion of the pledget's forward wall is medially folded on itself starting at notch 25, with adjacent halves of the forward wall surface in face to face engagement.

In the next step, FIG. 11, a circular plunger 27 is introduced into the bottom of the now circular die cavity while a cooperating plunger 26 with a concave conical cavity 28 in its leading end is introduced into the top of the circular die cavity and the two plungers 27 and 26 are moved toward each other to compress the pledget 10 into final tampon form with a main cylindrical portion 15 and a forward tip portion 16 of substantially conical shape.

When plungers 27 and 26 are moved apart after final compression the tampon slightly reexpands longitudinally as shown in FIG. 12 to arrive at the final self-sustaining tampon form desired.

Tip 16 is comprised of two substantially conic half sections 30 and 31, as shown in FIG. 12, with adjacent halves of the surface area of the starting forward wall of pledget 10 forming the interface between said sections, the forward wall being medially folded on itself at 25.

While a large variety of materials may be used to form the starting pledget, in one specific example the pledget was comprised of a blend of 60 percent cotton linters and 40 percent absorbent rayon fibers. The resulting batt was also wrapped with a fluid pervious cover of non-woven scrim and had a suitable withdrawal string attached near the base. A structure of this type is described in more detail in Bletzinger et al. U.S. Pat. No. 2,926,394 issued Mar. 1, 1960.

In this specific example, the starting batt or pledget measured about 31/2 inches long, 11/2 inches wide and three-fourths inch thick and weighed about 3.8 grams. The finished tampon was about 13/4 inches long with the cylindrical portion being about 11/8 inches long and the conical tip portion being about five-eighths inch long. The diameter of the cylindrical portion was about 0.550 inch. The average density of the tampon was measured and found to be about 0.75 grams/cc distributed as follows: In the cylindrical portion 0.75 grams/cc, in the tip 0.7 grams/cc and at the base of the tip 0.8 grams/cc.

To compare this structure with prior art patents a starting pledget of similar weight and dimension (FIG. 1A) was prepared except that a triangular section of material 31 was removed from the forward end of the pledget 10a before compressing, giving the pledget a rectangular shape with a V-notch in its forward end, the depth at the point of the V extending about five-eighths inch from an imaginary plane bridging the forward corners 32 and 33 of the pledget 10a. This pledget was compressed to a tampon of the same shape and size as set forth for the preferred tampon of this invention. The average density was about 0.7 g/cc distributed as follows: In the cylindrical portion about 0.75 g/cc; in the tip about 0.5g/cc and at the base of the tip about 0.7 g/cc.

Both types of finished tampons were then tested for absorption and reexpansion under simulated and actual use conditions. It was found that in the tampon of this invention which had no material removed from the tip area, the conical tip reexpanded rapidly to nearly rectangular shape, while the tip of the tampon formed from the pre-notched pledget remained in substantially conical form even after the rear, base portion of the tampon had reexpanded to a substantially rectangular form.

It is theorized that this happens because when the fibers of the forward wall are depressed as described above, the forward wall portion is formed into a springlike V, whereby the portion of the side walls included in the tip structure have a built-in outward bias which assists in forcing the side walls outwardly when absorbed fluid releases the compressed structure. In the tampon where material is removed from the forward end before compressing no such dormant outwardly biased forces are present.

It has also been determined that when the tampon pledget with the V-shaped depression in it is first precompressed in the longitudinal direction before any substantial transverse compression, it will re-expand first in the transverse direction before any substantial expansion in the longitudinal direction occurs. This initial transverse expansion in use is highly desirable in that it blocks potential leakage more quickly and effectively.

The improved structure of the tampon of this invention thus achieves one of the aims of ideal tampon performance, i.e. to have all portions of the tampon reexpand in the most effective manner as possible during use toward their original shape and size while still providing the compressed tampon with a reduced forward entrant portion for ease in insertion.

While reference to the term generally conical is made throughout this specification, it is meant to include a regular cone in which a section through the apex defines an equilateral triangle with opposing straight lines as well as a modified cone or a hemisphere in which a similar section defines a generally equilateral triangular configuration with opposing curved lines.

Claims

What is claimed is:

1. In an absorbent tampon of the type comprising an elongate rectangular pledget, having upper and lower walls of predetermined width, and two side walls and forward and rear end walls narrower in dimension than said width, with said pledget being compressed sufficiently to be self-sustaining in compressed condition in the form of a substantially cylindrical shape having a main cylindrical portion and a forward portion which is generally conical; the improvement wherein said conical portion comprises a pair of conic half sections with the planar surfaces of said sections in contiguous association, the interface between said contiguous planar surfaces being defined by adjoining face portions of the forward end wall of said pledget medially folded into mutual face-to-face contact, the line formed by said medial fold line being the base of a dormant outwardly biased springlike V which opens outwardly when released by absorbed fluid, the peripheral surface of said conical end portion comprised substantially of the outer surface of the respective forward portions of said upper, lower and side walls of said pledget, and a narrow sectional portion of said tampon taken at the approximate base of said conical portion being slightly more dense than said main cylindrical portion.