U.S. patent number 3,807,399 [Application Number 05/284,773] was granted by the patent office on 1974-04-30 for tampon applicator.
This patent grant is currently assigned to Kimberly-Clark Corporation. Invention is credited to Raymond A. Morman, Russell L. Noyes, Jr..
United States Patent |
3,807,399 |
Morman , et al. |
April 30, 1974 |
TAMPON APPLICATOR
Abstract
An arrangement for maintaining in slidable engagement a pair of
telescoping flexible plastic tubular elements such as are employed
for inserting tampons or the like. In the tube comprising the outer
element a short interior portion at the trailing end is tapered
down in diameter to provide the rear opening of the tube with an
internal diameter slightly less than the internal diameter of the
remaining major portion of the outer tube. The inner ejector
element is a tube of small diameter with a plurality of exterior
parallel fins uniformly spaced around the tube circumference and
extending longitudinally thereof. A line circumscribing the
external edges of these exterior fins is of a diameter
significantly larger than the internal diameter of the opening at
the trailing end of the outer tube but no larger than the internal
diameter of the remaining portion of the outer tube so that when
the two elements are fitted together the fin edges are in firm but
slidable engagement with the rear opening of the outer tube.
Inventors: |
Morman; Raymond A. (Neenah,
WI), Noyes, Jr.; Russell L. (Menasha, WI) |
Assignee: |
Kimberly-Clark Corporation
(Neenah, WI)
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Family
ID: |
26901391 |
Appl.
No.: |
05/284,773 |
Filed: |
August 30, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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206479 |
Dec 9, 1971 |
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Current U.S.
Class: |
604/14 |
Current CPC
Class: |
A61F
13/26 (20130101) |
Current International
Class: |
A61F
13/20 (20060101); A61F 13/26 (20060101); A61f
015/00 () |
Field of
Search: |
;128/285,263,261,270,218D,264 ;221/279 ;222/225,386 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Recia; Henry J.
Attorney, Agent or Firm: Hanlon; Daniel J. Herrick; William
D. Miller; Raymond J.
Parent Case Text
This application is a continuation-in-part of copending application
Ser. No. 206,479 filed Dec. 9, 1971 and now abandoned.
Claims
What is claimed is:
1. An applicator consisting of a pair of telescopically associated
flexible plastic tubular elements and comprising: an outer tubular
element having a major longitudinal portion of substantially
uniform internal diameter and a trailing end portion in which the
internal diameter is reduced to define a rear opening having an
internal diameter slightly smaller than the internal diameter of
said major portion of said outer element; an inner element
comprising a tubular structure of substantially smaller external
diameter than the internal diameter of said rear opening; a
plurality of substantially evenly spaced and parallelly disposed
fins protruding from the surface of the tubular structure of said
inner element and extending longitudinally for substantially the
full length thereof; the diameter of a line circumscribing the top
edges of said fins for the full length thereof except for a minor
tapered frontal portion being larger than the internal diameter of
said rear opening but no larger than the internal diameter of said
major portion of said outer element, whereby at least one of said
elements is caused to be radially distorted at the mutual area of
contact when said inner element is telescopically associated with
said outer element, said distortion being present as long as any
portion of the defined full length of said fins is in contact with
said outer element.
2. The applicator of claim 1 wherein said outer element is caused
to be radially distorted at said rear opening.
3. The applicator of claim 1 wherein said inner element is caused
to be radially distorted where it is in contact with said rear
opening.
4. The applicator of claim 1 wherein the tubular structure of said
inner element has an odd number of fins spaced therearound.
5. The applicator of claim 4 wherein said number is at least
three.
6. The applicator of claim 1 wherein the tubular structure of said
inner element has an even number of fins spaced therearound.
7. The applicator of claim 1 wherein the circumscribed diameter of
said fins is substantially constant for the full length of said
fins.
8. The applicator of claim 7 wherein said fins at the leading edge
of said inner element are tapered to form a nose with a truncated
conical-like structure.
9. The applicator of claim 1 wherein said fins are of rectangular
cross section.
10. The applicator of claim 1 wherein said fins are of tapered
cross section being wide at the base and narrow at the top
edge.
11. The applicator of claim 1 wherein the tube comprising said
outer element has an open front end and a compressed tampon is
disposed therein in frictional engagement with the interior wall
thereof.
12. The applicator of claim 1 wherein the tube comprising said
outer element has a substantially closed tapered front end formed
by flexible petals of juxtaposed substantially triangular
segments.
13. The applicator of claim 12 wherein a loose fitting tampon is
disposed within said outer element.
Description
RELATED APPLICATIONS
U. S. Ser. No. 168,851, Werner et al., filed Aug. 4, 1971 and
entitled "Locking Arrangement for Plastic Telescoping Tubes Used to
Insert Tampons and the Like."
BACKGROUND OF THE INVENTION
Inserter devices for catamenial tampons and the like comprising a
pair of telescopically associated tube-like elements of flexible
plastic such as polyethylene, polypropylene or the like are known.
However, because of the inherent flexibility and resilient memory
of plastic, the use of conventional locking devices between
telescoping tubes such as matched indentations or punched out
portions as used with prior art paper tubes is not practical.
Accordingly other interlocking means have been found necessary when
plastic tubes are used. Most of these means are incorporated into
the tube structure when first molded. A number of these
interlocking means rely on mated male and female portions, while
others depend on close frictional association of the adjoining
surfaces. Since the outer and inner elements are usually molded
separately, and have parts designed to cooperate with one another,
it is difficult to dimension the molding dies so that the molded
plastic parts fit precisely, simply because the molded plastics do
not retain their exact dimensions because of shrinkage or
expansion. It is desirable therefore to design a plastic structure
for applicator tubes which permits a wide range of tolerance in
dimensional specifications to allow for normal variations
encountered in mass production of plastics, and yet to insure that
the parts will cooperate as intended. Another reason for having a
wide tolerance range is that even if plastic could be precision
molded it is material of such a nature that it often expands or
contracts considerably when subjected to the extremes in heat or
cold normally encountered during warehousing and shipping, and any
real precision which may exist originally in mated parts is lost.
When this happens the effectiveness of ordinary frictional
interlocks are often destroyed.
In application Ser. No. 168,851 assigned to the same assignee as
the present application, there is disclosed one attempt at solving
the problem when frictional association is used as the interlocking
means. In that application there is described an outer tube in
which the internal diameter near the opening at the trailing end
tapers down to a diameter smaller than the internal diameter of the
major portion of the outer tube as in this application. The inner
tube acting as the ejector element has a small truncated conical
portion at its leading end followed by a large diameter portion and
then a smaller right cylinder barrel portion with an external
diameter slightly larger than the internal diameter of the rear
opening in the outer tube. The remaining portion of the inner tube
then tapers down slightly to an external diameter smaller than the
outer tube's rear opening. The difference between the internal
diameter of the rear opening in the inwardly tapered portion of the
outer tube and the external diameter of the barrel portion of the
inner tube provides an interference fit which retains the two tubes
in firm frictional engagement, yet because of the flexibility of
the plastic permits the tubes to be easily telescoped together when
longitudinal force is applied against the rear of the inner tube.
While this arrangement serves to accommodate to some degree the
ordinary variations in dimensions which occur in the molding
operation of the two tubes, a still wider tolerance is considered
desirable both to facilitate fabrication and to cut down on the
number of rejection of parts which may occur due to failure to meet
minimal dimensional variations.
The present invention is directed to cooperating tubular structures
which assure that a firm frictional engagement between the tubular
elements is provided even though a wider tolerance in dimensioning
is permitted, while still providing a smooth and easy telescoping
action between the tubes.
SUMMARY OF THE INVENTION
As indicated above, the applicator of this invention comprises a
pair of telescoping tube-like structures of flexible plastic. The
outer tube is preferably of right cylinder construction, but may
have a slight barely discernible forward taper or draw for ease in
molding. A short interior portion at the trailing end of the outer
tube is tapered down in diameter to provide the rear opening of the
tube with an internal diameter slightly less than the internal
diameter of the remaining major portion of the tube. The inner
ejector element comprises a central cylinder of significantly
smaller external diameter than the internal diameter of the outer
tube rear opening. Spaced around and protruding from the periphery
of this smaller diameter tube are a plurality of external
substantially parallel fins extending longitudinally of the
element. A line circumscribing the external edges of these fins has
a diameter substantially greater than the diameter of the rear
opening in the outer tube, but of less diameter than the internal
diameter of the remaining portion of the outer tube. The
circumscribed diameter is substantially constant for the length of
the element. A forward portion of each fin is preferably tapered to
give the finned tube a somewhat truncated conical forward end which
for assembly purposes permits easy insertion of the inner element
into the rear opening of the outer tube as well as serving to avoid
binding when a tampon of the like contained in the outer tube is
being ejected. When the inner element is inserted into the outer
tube, the rear opening in the outer tube flexes and is radially
distorted slightly out of round by the larger diameter dimensions
of the fins. The distortion or deformation of the rear opening is
readily permitted because of the spaces between fins. The slight
deformation of the rear opening in the outer tube serves to hold
the inner element firmly where contact is made with the fin edges
yet permits easy telescoping of the two tubular elements when
longitudinal forces are applied. By designing the fins with a
tapered cross section, wide at the bottom and narrow at the top,
the amount of static frictional engagement force is substantially
retained but the frictional resistance to dynamic force is somewhat
reduced.
The above features and other advantages of the present 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 side view partly in longitudinal section of an
applicator assembly in accordance with the invention.
FIG. 2 is an enlarged rear view of an outer tube of the type shown
of FIG. 1.
FIG. 3 is an enlarged and somewhat idealized section taken through
line 3--3 of FIG. 1.
FIG. 4 shows a modification of the FIG. 3 structure in which three
fins are shown in the inner element instead of five.
FIG. 5 is a perspective view of another modification of the
applicator in accordance with this invention, showing outer and
inner elements before assembly.
FIG. 6 is a perspective view of the outer and inner elements of
FIG. 5 in assembled condition.
FIG. 7 is a section of another embodiment of the inner tube showing
four fins.
FIG. 8 is a section similar to FIG. 4 except that the fins are
tapered in cross section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 there is shown an applicator structure comprising an
outer plastic element 10 with an inner plastic element 12 partially
telescoped therein. The outer element 10 which comprises a
thin-walled tube is shown in section to reveal a tampon body 14 in
light frictional contact with the interior wall 15 of the tube. The
usual withdrawal string 16 is attached to the rear of tampon 14 and
extends through a tubular central portion of inner element 12 to
protrude from the trailing end as shown. The tube of outer element
10 has a substantially uniform diameter throughout its length but
purposefully tapers down at 18 near its trailing end to provide an
opening 20 at the rear end of the tube which opening is of smaller
internal diameter than the internal diameter of the major portion
of the tube. Outer element 10 may also be provided with a
conventional reinforcing ring 11 at its trailing end to help in
grasping the tube during use.
Inner element 12 is shown in full side view in FIG. 1 and in
transverse section in FIG. 3 as taken at 3--3 of FIG. 1. Inner
element 12 comprises a tubular central section 22 of significantly
smaller diameter than opening 20 and a plurality of longitudinally
extending and substantially parallel fins 24 spaced around the
circumference thereof. The forward end of fins 24 of element 12 are
preferably tapered as shown at 25 to permit easy entry into opening
20. The rear end of element 12 may also be provided with a
reinforcing ring 23. A circular line circumscribing the top edges
26 of fins 24 has a diameter larger than the internal diameter of
the rear opening 20 in the outer tubular element 10, and preferably
slightly less than the internal diameter of the remaining portion
of the outer tube. This circumscribed diameter of the fins is
substantially constant for the full length of the element except
where the forward end is tapered at 25 as described above. With
this construction when an inner element 12 with five ribs 24 as
shown in the drawings is inserted into outer element 10 via rear
opening 20, the ring portion 13 of outer element 10 is radially
distorted out of its substantially circular configuration as shown
in FIG. 2 into a pentagon-like shape with arcuate sides 28. The
flexibility of the plastic permits this distortion, and the
resiliency of the plastic serves to hold inner element 12 securely
in place by seizing edges 26 of fins 24. Yet because fins 24 have
so little real area in actual gripping contact with opening 20,
inner element 12 is easily slidable within outer element 10.
Because the arcuate segments 28 which define opening 20 may be
deformed until they are almost straight without causing binding
between the elements, a large variance in the defined diameters
between the outer and inner elements is possible. Accordingly, the
die designer for these elements may allow for a wide range of
tolerance in arriving at the die dimensions needed for good
functionability.
In one specific embodiment, for example, in which the elements were
made of low density polyethylene, a wall thickness of the outer
tube was about 0.020 inch and the rear ring thickness was about
0.070 inch. The inner diameter of the major portion of the outer
tube was about 0.560 inch and the inner diameter of rear opening 20
of the outer element 10 was about 0.550 inch. The circumscribed
diameter of ribs 24 in element 12 was about 0.5572 inch making the
circumscribed diameter of the inner element about 0.0072 inch or
7.2 mils larger than the inner diameter of rear opening 20 in the
outer tube. With these dimensions the edges of fins 24 of inner
element 10 were held firmly by the outwardly stressed rear opening
of outer element 20 and was still freely slidable therein. Since
the circumscribed diameter of element 10 was constant for the
entire length thereof except tapered frontal area 25, inner element
12 was held securely by opening 20 at all points of traverse as
element 12 was slid into element 10. This ability to maintain firm
frictional contact throughout the length of ribs 24 permits tampon
14, or any other material contained in tube 10 for ejection
purposes, to be of any variable length consonant with the outer
tube size, and still be in firm contact with the leading end of
element 12.
Differences in inner element and outer element diameters of from as
little as 0.0015 inch to up to about 0.0180 inch are possible while
still obtaining satisfactory holding and telescoping action between
the elements. Again, as indicated earlier, it is understood that
the circumscribed diameter of the fins should not exceed the
internal diameter of the major portion of the outer tube. While the
above variations are useful, a diameter difference or interference
between the elements intermediate that range is preferred, and dies
are dimensioned so as to meet that intermediate range as closely as
possible.
In FIG. 4 there is shown an inner element with only 3 ribs 24a. In
this structure, span 28a between points of distortion is
considerably longer. There is a small reduction in static holding
power between the two elements, and dynamic force required to
telescope the tubes is reduced a bit more.
In FIG. 7 there is shown in cross section an inner element with
four fins. It will be noted in this construction, and any
construction with an even number of fins, the effective diameter is
much greater because the fins are exactly opposite each other.
Accordingly, an even-numbered fin construction would fit much
tighter than an odd-numbered fin construction with the same
circumscribed diameter, since the latter has a space diametrically
opposite each fin. The odd-numbered construction, therefore, is
preferred because it is possible to allow much greater tolerance in
dimension variations between the circumscribed diameter and the
diameter of the opening in the end of the outer tube.
In FIG. 8, ribs 24c are shown as being tapered in cross section
with edges 26c being considerably narrower. This construction seems
to grab the outer element better and insures against axial rotation
between the two elements, while still permitting easy telescoping
action as described earlier.
In FIGS. 5 and 6 there is shown a construction in which outer
element 40 has a substantially closed forward tip made up of
flexible petals of juxtaposed triangular segments 45; the rest of
the structure being the same as the outer element of FIG. 1.
For inner element 42, tubular portion 43 is shown as being
forwardly tapered instead of being a substantially cylindrical tube
as in FIG. 1. Fins 44 are otherwise the same as in FIG. 1 being
substantially parallel and having a substantially constant
circumscribed diameter from the end of the frontal taper to the
trailing ring section of the element.
Other than the above differences, the FIG. 5-6 embodiment varies
from the FIG. 1 embodiment primarily in the closed end structure of
the outer tube. This structure permits the manufacturer to include
within the outer element a loosely fitting tampon rather than a
tampon with the required frictional fit shown in FIG. 1.
Medicaments may also be disposed in the closed end outer tube if
desired since closed petals 45 will serve to contain the
contents.
It is also noted that while the outer element is shown as being
substantially a right cylinder tube, in fabricating such tubes it
is the practice to put in a slight, but hardly noticeable, taper or
draw to permit ready removal from the forming dies.
In the embodiment of FIGS. 5 and 6 it is also noted that because
the rear opening is only slightly reduced in diameter from the
inner diameter of the main portion of the tube a full-size tampon
or other body may be inserted from this end during fabrication
without disturbing the closed end structure.
In the foregoing description it has been noted that a slight
distortion or deformation of the rear opening of the outer element
occurs when the inner element having fins of larger circumscribed
diameter is inserted therein. Further observations indicate that
the inner element itself may also be subject to some deformation
depending upon the stiffness or flexibility of the plastic
employed, as well as upon the stiffness or flexibility of the
structure from which the fins extend. The amount of deformation of
either or both elements also depends upon the relative flexibility
of each of these structures to each other and upon the type of
plastic used. In any event, in order to produce a suitable slidable
fit between the elements, some deformation must take place in at
least one of the elements at their mutual area of contact when both
elements are telescopically associated.
For example, when the outer element is made of a firm and only
slightly resilient plastic, and the inner element is made of a
soft, highly flexible plastic, almost all of the deformation will
take place in the inner element in the area where the inner element
is in contact with the rear opening of the outer element. In this
case there will be substantially no deformation in the outer
element as in the preferred structures previously described. In
this variation also, the desired firm but slidable frictional
engagement of the two elements is obtained. In such an arrangement,
for example, a firmer plastic such as polypropylene, high density
polyethylene, rigid polyvinyl chloride or polystyrene may be used
for the outer element, and a low density polyethylene may be used
for the inner element. Of course when a tapered front end with
flexible petals is employed, the outer element should be made from
a plastic which is sufficiently flexible to permit the described
petals to open easily when a tampon is ejected.
Numerous combinations of plastics characterized by varying density,
hardness, and flexibility are comtemplated for use in the
invention. For example, materials such as high and low density
polyethylene, polypropylene, soft and firm polyvinyl chloride,
nylon, polyester, polyacrylate, polyvinyl alcohol and the like may
be used for either or for both elements.
* * * * *