Note: Descriptions are shown in the official language in which they were submitted.
INTRAUTERINE CON~RACEPTIVE DEVICES l:t7~8~4
~ND METHODS O~ l~ANUFACTURING SUCH DEVICES
BACXGROUND OF THE INVENTION
This invention relates to intrauterine
contraceptive devices and, more particularly, to such
devices which join copper or other metal contraceptive
materials to a plastic carrier to be positioned within
the uterus.
DESCRIPTION OF THE PRIOR ART
Intrauterine devices are well known as an effective
means for contraception. The preferred construction o~ these
I.U.D. devices combines a flexible plastic carrier for
holding metal having contraceptive properties, such as
copper. This combination of a plastic carrier holding copper
members has been recommènded by the World Health Organization
and the Population Council.
Plastic carriers are usually in the form of a "T"
or "7". In one form of construction, the copper sleeves are
applied to the stem and cross-bar of the "T", or horizontal
and vertical members of the "7". It is known that in such
construction, the internal diameter of the copper sleeves
is larger than the outer
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diameter of the member, bar, or stem of the I.U.D. When placed
into position, the copper is then bent in or swedged into place.
Swedging copper sleeves onto the plastic carrier has been
known to create certain problems. The swedging process may not
always be reliable, and the sleeves may slip either off the
carrier itself or to portions of the I.U.D. which decrease the
contraceptive effectiveness. For example, it is possible that
the copper sleeves might move together, which would thereby re-
duce the surface area of the rings, as a whole.
Slipping the sleeves over the carrier and then swedging
the sleeves into place has another disadvantage. The carrier
must have ends of sufficiently small diameter so that the sleeves
may fit over it. As a consequence, the terminal ends of the
carrier have been known to perforate the- uterine cervix and
inbed in the endometrium.
To prevent these perforations, health authorities have
insisted that the ends of the I.V.D. plastic carrier.be enlarged,
in the form of a small ball. However, this design eliminates
the possibility of slipping on the copper sleeves over the ends
~0 of the carriers and swedging them into position. Inserting the
sleeves on the carrier and reheating to form the ball ends causes
the plastic to become frangible.
As an alternative, one might consider injection molding
the plastic through the copper sleeves. However, this creates
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yet another problem. Where a succession of spaced copper sleeves
axe disposed, as on the stem, the injected plastic will become
frangible between the copper sleeves. There is also a tendency
for the plastic being forced through the copper to cover the
copper sleeves, thereby reducing their effectiveness.
An alternate embodiment places a copper helix about the
stem or vertical arm of the I.U.D. Typically, the helix is
formed by attaching one end to the stem and winding it to the
opposed end, where the wire is cut. This starting and stopping
of the winding process causes the copper wire to become weakened .
at the stopping and starting points. The result is that the wire
tends to easily break, causing injury.
In the past, a number of suggestions have been made to
improve upon the construction of I.U.Ds. For example, Kaivola,
in United States Patent No. 4,198,966, provides an I.U.D. which
uses the helix about the stem. In order to avoid the splitting
problem, a long helix is made and then cut to the desired length.
In order to hold the helix in position, one end is formed with
an enlarged body member and the opposed end is clipped or locked
into position to the cross-bar. The heavier shoulder, upon which
the helix rests, provides an obvious point of irritation in the
cervix.
In the prior art, combining of more than one type of
plastic to form an I.U.D. is well ~nown. However, none is used
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as a carrier for copper or other metallic contraceptives. Ex-
amples of this are suggested by Csatary in United States Patent
No. 4,182,321, Moulding in United States Patent No. 3,933,152,
and Haff in United States Patent No. 3,935,860.
SUMMARY OF THE INVENTION
. .
It is an object of the present invention to provide an
improved and novel I.U.D. device which has superior physiological
characteristics.
It is another object of this invention to provide an
I.U.D. device that may be easily manufactured.
It is another object of this device to provide an I.U.D.
which may be easily inserted into the uterus and which does not
interfere with the normal physiological processes, such as the
menstrual flow of the female body, and which is capable of
resisting expulsionary forces of the uterus.
It is yet another object of the present invention to
provide an improved and novel I.U.D. device which will retain
thereon the metallic contraceptive material without piercing
the uterine walls.
It is still another object of this invention to provide
an I.~.D. plastic carrier which resists frangibility and retains
the cont ceptive copper thereon.
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It is yet another object of this invention to
provide a me-thod of manufacturing I.U.D. devices which is
simple and inexpensive.
It is a further object of this invention to provide
a method of manufacturing an I.U.D. device which combines two
types of plastics with the metallic contraceptive material
in such a manner as to maintain the contraceptive metal in
place.
In accordance with one aspect of the present
invention there is provided an intrauterine contraceptive
device including a first plastic material having a first melting
point and a second plastic material having a lower, second
melting point. The first and second materials are combined
such that the first plastic material is joined to the second
material to act as a skeleton for the second plastic material.
An exposed copper member is at least in part supported by the
combined first and second plastic materials, the first and
second materials forming a carrier.
According to another aspect of the invention there
is provided a method of making an intrauterine contraceptive
device, the method including the steps of providing a
first plastic material having a first melting point, providing
at least one copper member and assembling the copper member upon
the first material, and providing a second plastic material
having a second melting point, the second melting point being
lower than the first melting point. The second plastic is
molded in a molten state into combination with the first
plastic material, leaving the copper member exposed, the first
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plastic material remaining substantially in a solid state
during the molding process, such that the first plastic
material acts as a supporting skeleton for the second plastic
material.
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The second plastic~ in a molten state, is combined
with the first plastic member With the metallic member exposed,
¦ The first plastic member remainS substantially in a solid state
during the molding proCess such that the first plastic member
S acts as a SUpporting skeleton for the second plastic member,
BRIEF DESCRIPTION OF THE DRAWING
FIG, 1 is a plan view of an I.U.D. constructed in
accordance with the teachings of this invention;
FIG, 2 is a seCtion of the device of FIG, 1 taken along
lines 2-2;
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FIG. 3 iS a plan VieW of another l.U,D, constructed in
accordance with the teachings of this invention; and
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FIG. 4 iS a section of the device of FIG. 3 taken along
lines 4~4.
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DESCRIPTION OF THE PREFERRED ENBODIMENTS
For the,purposes of this example, the I . U. D. of this
~inVention assumed to be a ~T". It will be understood~ however~
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¦ that this invention is applicable to other suitable configurations
such as the figure "7". This invention provides a flexible
plastic carrier for positioning and retaining a metallic contra-
ceptive in the uterus.
S Copper is referred to throughout as the contraceptive
metal of choice. It will be understood, however, that copper
refers to any other equivalent metal contraceptive material
throughout the specification and claims.
As previously indicated, one of the major difficulties
in swedging copper sleeves onto an I.U.D. flexible plastic
carrier is that, in so doing, the sleeves may become dislodged
and either fall from the I.U.D. or cause the I.U.D. plastic
carrier to break. If the plastic is injection-molded through
the copper sleeve, the plastic will have a tendency to ride up
over the copper, reducing its contraceptive effèct or forming a
weakened support member.
Turning to the drawing, there is provided an I.V.D. 10
in the shape of a "T". A plastic material in the form of a
thread 12 is part of the I.V.D. 10. A second plastic material
14 is combined with the thread 12. The thread 12 pxeferably has
a higher melting point than the second plastic material 14. In
this example, the thread is, preferably, made of nylon.
~ mold (not shown) is used to form the I.U.D. device 10.
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¦Such molds are well known in the art. The mold, itself, has
¦indentations intended to receive copper sleeves. Such sleeves
¦are also well known in the art. An indentation in the mold is
¦provided for each of the copper sleeves 16. The I.U.D. 10, as
S ¦previously indicated, is "T"-shapqd with a cross-bar 18 and a
¦stem 20. The nylon thread 12 is knotted 22 and 24 at a location
¦which corresponds to the opposed ends of the stem 20. The stem's
¦ copper sleeves 16 may first be threaded upon the thread 12 and
¦ then placed in the mold. The ~ree end 26 of the thread 12 ~ay
¦ extend beyond the free end 28 of the stem 20. The function of
this free end 26 will be more fully discussed below.
; The remaining copper sleeves may be placed into positionin their respective mold locations along the cross-bar 18 of the
I.U.D. 10. The plastic 14, which makes up the body of the I.U.D.,
is then injected into the mold in a molten state. Any plastic
having a lower melting point than the thread 12 may be used to
form the I.U.D. Thus, for example, polyethylene or polypropylene
may be used, as is commonly used as an I.U.D. carrier. It will
be noted that, upon the completion of the molding process, the
free end 28 of the stem 20 may have an enlarged or bàll-like end
30. In addition, the free ends of the cross-bar 18 may also have
enlarged ball-like ends 32 and 34. This is the preferred con-
s~ruotion in or~er to prevent the I.U.D. 10 from piercing the
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vaginal wall. It will be noted that the thread 12 is not in
the cross-bar 18. While a thread may be disposed in the
cross-bar 18, it is believed not to be necessary in
satisfactorily forming the I.U.D. The thread 12 in the stem
20 of the "T" I.U.D. 10 acts as a skeleton. In this case,
the endoskeleton 12 holds the plastic carrier firmly in
position and prevents it from being frangible. The plastic
14 covers the thread 12 and the thread knots 22 and 24.
The molding process, itself, holds the sleeves 16 in position,
as do the sleeves along the cross-bar. The extending r
integrally formed end 26 of the thread 12 acts as a
convenient means for removal of the I.U.D. 10. The advantageof this construction is that, unlike prior art I.U.Ds., the
free end of the thread need not be attached as a separate step
in the manufacturing process.
! The knotted ends 22 and 24 of the thread 12 maintainthe position of the thread 12 during the injection-molding
process.
In yet another embodiment of an I.U.D. 36 (FIG 3),
a helis of copper wire 38 may be wound upon a plastic tubing
or spaghetti 40. Typically, this can be done by an extended
length of the spaghetti 40 being supported upon a mandrel.
This plastic material 40 should be preferably made of a
material with a relatively high melting point, such as nylon,
or polytetrafluoroethylene which is sold under the trade mark
"Teflon", or the like. By winding the copper helix over a
long distance and then cutting
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the spaghetti 40 into appropriate lengths, the stem 42
of the "T"-shaped I.U.D. 36 may be formed. The pre-cut
helix-spaghetti combination 38 and 40 may then be inserted
into a mold. Copper sleeves 42 may then be disposed in the
mold at the points corresponding to sleeve location on the
. cross-bar 44 of the I.U.D. 36. Molten plastic material 46,
such as polyethylene or polypropylene, having a lower melting
point than the spaghetti 40, may then be injected into the
mold, in a rnanner well known in the art, to fill the spaghetti
40 and form both the stem 42 and the cross-bar 44. In the
injection molding process, a ball~like end 48 is formed at the
free end of the stem 42 and cross-bar ends 50 and 52.
The foregoing combination provides a plastic
exoskeleton 40 which acts- to prevent the injected molded
- plastic member from coming up betweèn the helix 38. At the
~ same time, the co~bination of the plastic sleeve and the
internal plastic provides a flexible member which will not
yield or break under the movement within the vaginà.
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The thread 12 m~y also be molded into the second e~bodi-
ment (FIGS. 3 and 4). In this latter case,! how~ver, the thread is
not necessarily molded through the entire length of the stem to
form an enaoskeleton. Rather, the thread is molded at the end
as a convenient means of attachment during the molding process.
One significant problem arising from the use of the
removal thread has been the tendency of the end, if cut too short,
to prick a penis. To avoid this, the nylon thread may be preheate 3
into a coil or helix. Upon being cut, the remaining length will
bend to!one side, thereby avoiding the terminal end coming into
contact with the penis.
Another aspect of this invention, quite apart from the
use of the combined plastics wherein one of the plastics acts
as a supporting skeleton for the other, is the joining of the
thread to the I.U.D. In the past, such threads were easily
removed. It has been observed, however, that by extending the
threaa within the stem of the T or vertical arm of the U I.U.D.,
the thread can be molded in and will be retained by the I.U.D.
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