Applicator Tube For Inserting Hygienic Media

Abstract

A plastic applicator tube for inserting hygienic media into body cavities in which the forward end of the tube has a substantially closed dome-like or tapered structure comprised of juxtaposed triangular-shaped flexible segments adapted to open radially outward when the hygienic media is expelled therethrough. The tube is injection-molded or thermo-formed so that at least the outwardly facing edges of the juxtaposed sides of the segments have a rounded contour in cross-section. When the outwardly facing edges are formed by injection molding, the outer circumferential surface area of the segmented tube end is also free of the flash which sometimes forms during such molding.

Description

BACKGROUND OF THE INVENTION

In the evolutionary development of thin-walled applicator tubes for inserting hygienic media such as tampons and suppositories into body cavities, a recent advance has been the appearance in the marketplace of tubes having a tapered front end of substantially closed structure which is adapted to open radially when the hygienic media disposed in the tube is ejected therethrough.

The employment of a closed, tapered, end structure has two objects in mind. One object is to protect the contents from contamination. The other and more important object is to provide the tube with a reduced diameter leading end in order to facilitate penetration of the body orifice into which it is to be inserted. In the first stage of development, the tapered end comprised paper tubes having dovetailed folds pressed together to form a smooth, substantially continuous surface. In the next stage of development, the tubes were injection-molded or thermoformed from flexible plastic, such as medium or low density polyethylene, and the tapered ends comprised a plurality of juxtaposed petal-like flexible segments which opened outward when the tube contents were ejected therethrough.

In designing the segmented tapered end for these plastic tubes, it was considered desirable to have the juxtaposed side edges of the segments in as close a physical proximity as could be obtained by known production means, in order to present as smooth and continuous an entry surface as was possible.

It was also considered necessary to make the segmented structure flexible enough to permit the segments to flex outward and to open easily after the tube is inserted in order to facilitate the expulsion of hygienic media therethrough. However, in providing this needed flexibility for ejection purposes other problems relating to insertion were found. For example, during insertion the forces needed to push open the sphincter muscles located at the entrance of natural body orifices caused the flexible segments to partially collapse and deform, both prior to penetration of the orifice, and during insertion as the leading end passes through the orifice. This partial collapse and deformation of the segments caused the juxtaposed sides of the segments to slide over and under one another whereby portions of the side edges and the tips were exposed. Careful examination found these edges and tips to be quite sharp and this sharpness was attributed in part to the molded shape. Thus, when the body tissue was contacted by these exposed edges and tips during insertion, the danger arose that the tissue might be scratched, abraded, or lacerated.

While these disadvantages could be partially alleviated by structurally reinforcing the segments to prevent distortion or collapse, further extensive experimentation found that such reinforcement either increased the force needed to open the segments, or required such complicated structures that economical production was difficult to obtain.

The present invention is directed to an improved structure for the segmented entrance portion of tapered plastic tubes which is adaptable to efficient production and which retains the desirable flexibility of these segments, while insuring against exposing the body tissues to the sharp side edges and tips which otherwise might cause tissue damage when the partial collapse of the segments occurs during insertion.

SUMMARY OF THE INVENTION

The improved applicator tube of this invention comprises a cylindrical tube, injection-molded or thermoformed from flexible plastic, and having a tapered, substantially closed leading end. The tapered end is comprised of a multiplicity of juxtaposed, flexible triangular-shaped segments with at least the free outwardly facing edge portions of the juxtaposed sides of said segments having a rounded contour in cross-section. By molding rounded edges on at least the outwardly facing portion of the free edges of the segments, the outer circumferential surface of the tapered and segmented end of the tube is also free of the flash which is frequently formed during injection molding.

Other features and advantages of the invention will become apparent by referring to the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side view of a typical telescoping tube applicator with the outer tube having a substantially closed, tapered and segmented leading end.

FIG. 2 is a greatly enlarged face-on view of the leading end of the tube applicator shown in FIG. 1.

FIG. 3 is a still more greatly enlarged partial section taken along line 3--3 of FIG. 2 showing the typical cross-sectional configuration of the side edges of the segments in a plastic tube of the type made prior to introducing improvements of this invention.

FIG. 4 is a greatly enlarged partial section similar to FIG. 3 and showing a preferred embodiment of the cross-sectional edge structure of this invention.

FIG. 5 is a greatly enlarged partial section similar to FIGS. 3 and 4 and showing another embodiment of the invention.

FIG. 6 is a partial longitudinal section thru a typical mold used for injection molding closed end applicator tubes showing an arrangement of the core and cavity elements.

FIG. 7 is a greatly enlarged partial cross-section through an injection mold showing the portions of the core and cavity which mold the edge of segments in the configuration shown in FIG. 3.

FIG. 8 is an enlarged partial cross-section similar to FIG. 7, but showing a mold portion suitable for forming the segment edges shown in FIG. 4.

FIG. 9 is an enlarged partial cross-section similar to FIGS. 7 and 8, but showing a mold portion suitable for forming the segment edges shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A typical tube applicator, in which the improvements of this invention are embodied is shown in FIG. 1. The applicator shown there comprises an outer tube 10 and an inner tube 12. Outer tube 10 has a forward end 14 comprised of a multiplicity of triangular-shaped segments 15, and a raised ring 11 at the rear end for use as a finger grip. Inner tube 12 is telescopically positioned inside outer tube 10 and also has a raised ring 13 at its rear end. The improvement of this invention lies in the structure of the free edges of segments 15, and a much enlarged, face-on view of the segments is shown in FIG. 2. In that figure, the free unattached tips of five convex triangular segments 15 converge around a central opening 16, and the free side edges 17 are separated by narrow spaces 20. Raised ring 11 at the rear of the tube is also visible in this view.

Before proceeding with the detailed description of the advances provided in tube applications made in accordance with this invention, it would appear appropriate to review in more detail some additional background information.

The preferred and most efficient method for forming hollow closed-end cylindrical objects from thermoplastic material is by injection molding, although thermoforming of precut cylinders is also feasible. In injection molding, the molds designed for this purpose, and as illustrated in FIG. 6 with respect to applicator tubes, are usually comprised of a central core section 30 and a mating cavity section 32. For making the closed end tubes of this invention, core section 30 has a number of spaced ribs 39 at its rounded end to form the individual segments described in this invention. In this view only one rib 39 is shown. Core 30 has an indentation 40 at its tip to mate with a positioning pin 33 in cavity 32 to properly index and seat core 30 in cavity 32 in order to provide suitably spaced circumferential areas 34 in which the cylindrical walls of the tube are shaped. Molten thermoplastic is fed into the mold through hot runner 42 in the direction of arrow 35 through pinpoint gate 41 into circumferential area 34 to form the tube. Gases which must be expelled from mold areas 34 as they are filled with plastic are vented through suitable apertures 37 which are kept clean when core 30 is removed after each injection. In this particular embodiment five pin point gates 41 are used; one for each segment. When grooves, indentation, gaps, or spaces are required features in the wall structure of the object being molded, it is customary to have the forming elements or raised areas needed to mold such configurations located on the outer surface of the core 30 rather than on the inner walls of the cavity 32. Such location is preferred because it is much easier to machine and shape the core section of the mold than it is to provide such structures on the cavity section. Accordingly, in designing the mold for forming tapered segmented ends on closed applicator tubes of the type defined herein raised rib areas 39 were machined in the aforementioned traditional way onto the surface of core 30 to provide suitably spaced segments 15 (FIGS. 1 and 2) on the tapered or domed tip 14 of the applicator tube. An enlarged sectional view of such a rib 39 is shown in FIG. 7. Five circumferentially spaced ribs of this type were used on the core to provide the segments 15 with closely spaced free edges 17 as more clearly shown in FIG. 2. The positioning core pin 33 also serves to form a central aperture 16 defined by the tips of segments 15 in the leading end of the tube. When polyethylene is used in forming the tube, and when molds of the type described above are employed in molding tubes, the resulting product has a very smooth domed tip. When this tip is touched to the skin with light pressure it relays the tactile impression of having a soft smooth and substantially continuous surface.

The free tips and edges 17 of the segments molded in this manner have relatively thin sides as shown in FIG. 3 and these thin sides remain juxtaposed and are not exposed to the touch when only slight pressures are exerted on the tube end. However, when the tube is pressed more firmly against a resisting surface or small-sized orifice with the amount of pressure normally needed to carry out the insertion process, it is found that the walls of the segments 15 are distorted to such an extent that the thin free edges 17 slipped over one another causing portions of the side edges and especially the tips of some of the segments to protrude out of their unstressed smooth configuration sufficiently to directly contact the surface against which they are pressed. Due to the very thin nature of these side edges 17 it became apparent that when they rub against the skin they may occasionally snag and in so doing cause surface damage as insertion takes place.

The tactile effect which these sharp displaced side edges conveyed, even in sight and handling tests, was one of undesirable roughness, and as indicated above the fact that these sharp edges might occasionally abrade or cut the tissue with which they come into contact dictated against the suitability of such tube structures for their intended use. A remedy was deemed essential. It was noticed further that in this construction, some small amounts of flash 18 are present adjacent the top side of the free edges 17. This flash 18 clearly gave those initially thin edges a still thinner and still sharper contour than such edges 17 would be if they were free of flash. Flash, of course consists of minor amounts of the excess plastic which forms in mold crevices or joints when the plastic material is forced into these crevices under the pressure of molding.

From the above observations it was concluded that the presence of such flash should be minimized as much as possible if the described undesirable situation were to be cured. However, the elimination of flash which arises from injection molding was not possible, because no matter how closely the tolerances are machined in matching core and cavity molds, some flash inevitably will form in the molded product. In addition, the amount of flash increases as the molds gradually wear in use. The best solution therefore, with respect to the flash problem, seemed to lie in relocating areas where flash would develop so that the presence of flash would be as innocuous as possible.

While it was found that when the applicator is used for tampon insertion the collapse and distortion problem could be alleviated to a degree by forming the leading end of the tampon itself to match more closely with the internal contour of the applicator tube, and by assuring that the tampon tip is pressed firmly against the inside of the segments to keep the tampon and segments in this close contact at all times before insertion, such niceties were found to be impossible in mass production and in use. In examining representative samples of the mass produced product as packaged, it was found that in most cases there was little or no contact between tampon surface and tube interior in the finished product. Tampon shapes as formed, varied under even the best conditions, and upon storage some of the tampons were displaced while others expanded enough to force the segments open and expose both the free side edges and the tips even before use. Accordingly some other solution appeared necessary.

It was found that an unexpected and surprisingly simple solution to the problem could be obtained by modifying the cross-sectional contour of the side edge structure of the segments. It was also found that this modification could be readily adapted to injection molding by departing from traditional techniques in the forming mold design.

The latter solution consisted in remodeling the mold by moving the ribs which form the spaces between segments from their normal position on the outside surface of the mold core 30 to what ordinarily would be a less desirable position on the inside wall of mold cavity 32.

A typical example of this modification is shown in FIG. 8. In the portion of the mold shown in FIG. 8, core section 30a does not have a forming rib. Instead a forming rib 38a is positioned on the wall of cavity section 32b. This style of mold was then used to form segments 15a with rounded side edges 17a on their outwardly disposed face as shown in FIG. 4. Further, any flash which formed during molding was now located along the inside wall of the segments, as shown at 18a. The circumferential surface of the tube was therefore free of flash.

When the free edges 17a of the segments were formed in this manner, it was found that while the thus formed segments still would deform under pressure, as earlier described, the free edges did not tend to slide over each other as readily as they did in the FIG. 3 configuration when insertion pressures were applied to the tube tip. In addition, it was found that when pressure and resultant deformation were such that the segments did slide over each other, the thicker free edges thus exposed no longer were sharp enough to cause tissue damage. Subjective tactile, and use tests confirmed this. No rough feel to the touch as with the predecessor tubes was reported, and no instances of tissue abrasion were reported.

While the FIG. 4 configuration of the free segment edges is preferred, other variations are possible. The important consideration appears to be that the outwardly facing free edges of the juxtaposed flexible segments should be rounded in cross-section contour, and that the edges should be as thick as possible commensurate with molding techniques.

By referring to FIGS. 9 and 5 another form of improved edge structure may be found. In this modification, as shown in FIG. 9, core 30b of the mold has a small rib 39b which is matched with a similar rib 38b on cavity section 32b. The product formed from use of this arrangement, as shown in FIG. 5, is provided with segments in which the free sides 15b have a rounded cross-section contour 17b on the outward edges of the segments as well as having a rounded cross-section contour 19b on the internal edges of the segments. Any flash which results is located at the approximate center of the segment sides. While this configuration is not believed to be as good an edge structure in performance as that shown in FIG. 4 it is still considered an improvement over the FIG. 3 structure.

It will be noted that the above description and drawings refer to and show only a telescoping tube applicator. Nevertheless, it will readily be seen that the invention is equally applicable to any flexible plastic applicator in which the leading end of the inserter tube itself is tapered and comprised of a multiplicity of flexible juxtaposed segments.

While the embodiment shown in the drawing has five segments, it is apparent that the number of segments may be varied and still enjoy the advantages of the improved edge structure of this invention.

The material from which the tube is made can comprise any of the large number of flexible plastics capable of being injection molded or thermoformed such as high and low density polyethylene, polypropylene, nylon, polyester, and the like.

The improved tube is especially suitable for use in inserting absorbent tampons for catamenial purpose, but is equally useful for inserting medicated tampons, suppositories, various medicaments and the like into body cavities.

Claims

What is claimed is:

1. In an applicator tube of the type adapted for inserting hygienic media into body cavities and comprising an injection-molded thin-walled tube of flexible plastic in which the forward end portion of the tube is in the form of a tapered structure made of a multiplicity of juxtaposed triangular-shaped segments having free unattached side portions and adapted to open radially outward when tube contents are expelled therethrough, the improvement wherein the outwardly facing edges of the free unattached side portions of the segments as molded have a smoothly rounded contour in cross-section, said outwardly facing edges being completely free of flash, and any flash formed during molding being confined to the segment edge portions disposed at the inside walls of the tube.

2. The applicator tube of claim 1 wherein the inwardly facing edges of the free unattached side portions of the juxtaposed segments as molded are also smoothly rounded in cross-section.