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2. Field of the Invention
The present invention is in the field of hypodermic syringes and needles.
More particularly, the present invention is directed to a disposable
hypodermic syringe and needle combination which has a retractable sheath
to prevent accidents and abuse of the syringe and needle combination.
3. Brief Description of the Prior Art
Disposable hypodermic syringes and needles have been known in the art for a
long time.
Hypodermic syringes and needles are often used for administering medication
to patients suffering from infectious diseases. Therefore, it has been
considered of great importance in the art to avoid accidents where
doctors, nurses, or other persons are wounded by used hypodermic needles.
Presently, the safe disposal of used syringes and needles is considered a
serious problem in the art, particularly in light of the recent spread of
acquired immunodeficiency syndrome (AIDS), and of the widespread abuse of
syringes and needles by addicts for administering illicit drugs.
In order to solve or ameliorate the foregoing problems, the prior art has
provided rigid, puncture resistant disposable plastic containers into
which doctors or nurses are expected to deposit disposable hypodermic
syringes and needles immediately after their use. The containers, filled
with the discarded syringes and needles, are then sealed and eventually
disposed of. The disposal is ideally conducted in a manner which does not
permit access to unauthorized persons desiring to obtain the syringes and
needles for illegal or like abusive purposes. In spite of the foregoing
and other precautions, accidents still occur with used hypodermic needles,
sometimes with tragic consequences. Moreover, discarded syringes and
needles are still often misappropriated for illegal, or drug abuse,
purposes.
The foregoing problems remain especially acute in connection with syringes
and needles used by paramedics, because paramedics often are unable to
carry the specialized plastic containers required for safe disposal.
Moreover, personnel working in housekeeping duties in hospitals presently
are still often exposed to improperly discarded hypodermic syringes and
needles. The present invention is designed to solve or substantially
ameliorate the above-described problems.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a disposable hypodermic
syringe and needle combination wherein the needle is protected before and
after use, to prevent accidents involving the used needle.
It is another object of the present invention to provide a disposable
hypodermic syringe and needle combination wherein the needle is protected
before use, and wherein the needle is permanently and irreversibly
concealed after use so as to prevent abuse by users of illicit drugs.
The foregoing and other objects and advantages are attained by a hypodermic
syringe and needle combination having a sheath mounted to the barrel in a
first position wherein the sheath extends and conceals the needle. The
sheath is movable on the barrel to occupy a second position wherein the
needle is at least partially exposed. The needle and syringe combination
is normally used to fill the syringe with medication and inject it into
the patient in the second position of the sheath. The sheath is also
movable to a third position on the barrel wherein the sheath again
conceals the needle. The sheath is preferably irreversibly locked into the
third position for disposal so that the combination cannot be retrieved
and used for illegal or unauthorized purposes.
In accordance with another feature of the invention, the sheath is made
from a plastic material which softens and loses its structural integrity
at temperatures below the autoclaving temperatures required for
sterilizing items in medical practice. Consequently, the needle and
syringe combination is destroyed upon attempted sterilization in an
autoclave, because the sheath "melts" and renders the combination
unusable. This feature ensures that the combination is used only once.
The features of the present invention can be best understood together with
further objects and advantages by reference to the following description,
taken in connection with the accompanying drawings, wherein like numerals
indicate like parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a first preferred embodiment of the
hypodermic syringe and needle combination of the present invention, the
view showing a protective sheath extended to cover and conceal the needle;
FIG. 2 is another perspective view of the first preferred embodiment, the
view showing a protective sheath retracted, thereby exposing the needle;
FIG. 3 is still another perspective view of the first preferred embodiment,
the view showing the protective sheath again extended and locked into
position after the combination has been used;
FIG. 4 is a cross-sectional view taken on lines 4,4 of FIG. 1;
FIG. 5 is a cross-sectional view taken on lines 5,5 of FIG. 2;
FIG. 6 is a cross-sectional view taken on lines 6,6 of FIG. 3;
FIG. 7 is a partially exploded side view of the first preferred embodiment;
FIG. 8 is a side view of the first preferred embodiment with a portion of
the protective sheath broken away, the view showing the protective sheath
in its extended position covering the needle;
FIG. 9 is a partial side view of the first preferred embodiment, with a
portion of the protective sheath broken away, the view showing the
protective sheath in its retracted position wherein the needle is exposed;
FIG. 10 is another partial side view of the first preferred embodimett,
with a portion of the protective sheath broken away, the view showing the
protective sheath in its extended locked position covering the needle;
FIG. 11 is a cross-sectional view, the cross-section being taken on lines
11,11 of FIG. 8;
FIG. 12 is a perspective view of a second preferred embodiment of the
hypodermic syringe and needle combination of the present invention, the
view showing a protective sheath extended to cover the needle;
FIG. 13 is a side view of the second preferred embodiment, partly in
cross-section, the side view showing the protective sheath extended to
cover the needle;
FIG. 14 is a partial side view of the second preferred embodiment, partly
in cross-section, the view showing the protective sheath retracted to
expose the needle;
FIG. 15 is a cross-sectional view of the second preferred embodiment, the
cross-section being taken on lines 15,15 of FIG. 13;
FIG. 16 is a partial cross-sectional view of the second preferred
embodiment, the cross-section being taken on lines 16,16 of FIG. 15;
FIG. 17 is a partial cross-sectional view of a third preferred embodiment
of the hypodermic syringe and needle combination of the present invention,
the view corresponding to an extended position of a protective sheath to
cover the needle;
FIG. 18 is another partial cross-sectional view of the third preferred
embodiment, the view corresponding to an extended and irreversibly locked
position of the protective sheath to cover the needle;
FIG. 19 is a side view, partly in cross-section, of a fourth preferred
embodiment of the hypodermic syringe and needle combination of the present
invention, the view showing a protective sheath extended to cover the
needle;
FIG. 20 is another side view, partly in cross-section, of the fourth
preferred embodiment, the view showing a protective sheath retracted to
cover the needle;
FIG. 21 is a cross-sectional view taken on lines 21,21 of FIG. 19;
FIG. 22 is a cross-sectional view taken on lines 22,22 of FIG. 21, the view
corresponding to an extended position of the protective sheath to cover
the needle;
FIG. 23 is another cross-sectional view of the fourth preferred embodiment,
the view corresponding to a locked position of the protective sheath to
cover the needle, and
FIG. 24 is a cross-sectional view taken on lines 24,24 of FIG. 23.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following specification taken in conjunction with the drawings sets
forth the preferred embodiments of the present invention. The embodiments
of the invention disclosed herein are the best modes contemplated by the
inventor for carrying out her invention in a commercial environment,
although it should be understood that several modifications can be
accomplished within the scope of the present invention.
Referring now to FIGS. 1 through 11 of the appended drawings, a first
preferred embodiment 30 of the hypodermic syringe and needle combination
of the present invention is disclosed. The first preferred embodiment 30
includes a syringe barrel 32 and a plunger 34 mounted into the barrel 32
at its first end 36. A hypodermic needle 38 is mounted in a conventional
manner to the second end 40 of the barrel 32.
As an important novel feature, a sheath 42 is mounted to the barrel 32 at
the same end 40 of the barrel 32 where the needle 38 is mounted. As is
best shown on the perspective view of FIG. 1, in its normal or first
position, the sheath 42 is disposed to conceal and cover the needle 38.
The combination of the first preferred embodiment 30 is assembled during
manufacture, and is kept, during shipping, storage, and preliminary
preparation for administration of medication (not shown) to a patient (not
shown), with the sheath 42 in its extended first position. To insure
sterility, the sheath 42 is preferably sealed to the barrel with an
airtight flexible plastic wrap (not shown) The flexible wrap (not shown)
also serves as a tamper indicator.
The end 44 of the sheath 42, which is remote from the barrel 32, is tapered
in the first preferred embodiment 30, and bears a friction fitted plastic
cap or cover 46. The cap or cover 46 is shown on FIGS. 1 and 8.
As is apparent from FIGS. 1 through 11, the sheath 42 can be moved on the
barrel 32 to expose the needle 38 when it is desired to fill the barrel 32
with medication (not shown) and administer the medication (not shown) to a
patient (not shown). More particularly, the sheath 42 is locked in its
first position to the barrel 32, but can be dislodged from the first
position to be moved to a second position to expose the needle 38. The
second position is shown on FIG. 2. Still a third position of the sheath
42 relative to the barrel 32 and needle 38 is shown on FIG. 3. In the
third position, into which the sheath 42 is placed for disposal of the
hypodermic syringe and needle combination 30, the sheath 42 is
substantially irreversibly locked to cover and conceal the needle 38.
Consequently, in its "disposal state", the hypodermic syringe and needle
combination 30 cannot be accidentally reused, and the needle 38 is
prevented from accidentally wounding someone, thereby potentially
spreading dangerous infectious disease. As an added safety feature, after
the sheath 42 is locked into the third position shown on FIG. 3, but
before final discarding, the cap or cover 46 is preferably refitted to the
sheath 42.
The above-described functions of the preferred embodiment 30 are
accomplished by the structure illustrated in FIGS. 1-11. More
particularly, the surface of the barrel 32 includes a channel or groove
having two interconnected elongated parallel portions, which respectively
bear the reference numerals 48 and 50 on the drawing Figures. The interior
surface of the sheath 42 includes a protrusion or boss 52 which fits into
and is guided in the channels 48 and 50. The channels or grooves 48 and 50
are approximately 0.008" to 0.012" deep.
The partial cross-sectional view of FIG. 4 shows the boss 52 placed into
the channel 48 in the first position of the sheath 42 (in which the
combination 30 is normally kept prior to use). In order to reversibly lock
the sheath 42 in this position the guide channel 48 has a depression or
cavity 54 in a location corresponding to the location of the boss 52 in
the first position of the sheath 42. The cavity 54 includes a camming
surface 56 comprising a slope or a radius, which permits the substantially
square-shaped boss 52 to ride out of the cavity 54 in one direction only.
FIG. 4 also shows a slope or camming surface 58 at the end 40 of the
barrel 32, which permits the initial mounting of the sheath 42 on the
barrel 32 without serious interference by the boss 52. FIG. 7 shows well
the interconnecting guide channels 48 and 50, and also shows the sheath 42
before it is initially mounted to the barrel 32. The configuration of the
cavity 54 shown on FIG. 4 renders it substantially impossible to remove
the sheath 42 from the barrel 32 without breaking or damaging the boss 52
and thereby the entire combination 30. In addition to FIG. 4, FIGS. 8 and
11 also show the sheath 42 mounted to the barrel 32 in the first position
wherein the boss 52 engages the cavity 54 in the guide channel 48.
FIGS. 2, 5, and 9 indicate the second position of the sheath 42 relative to
the barrel 32. In this position, the boss 52 of the sheath 42 engages a
second depression or cavity 60, which is located almost at the upper end
of the guide channel 48. The shape or configuration of the second cavity
60 is similar to that of the first cavity 54, so that the boss 52 can ride
out of the second cavity 60 in the upwardly direction only.
FIGS. 6 and 10 show the boss 52 of the sheath 42 engaging, in the third
position of the sheath 42, a third depression or cavity 62 located
substantially at the lower end of the guide channel 50. The third cavity
62 has no slope or camming surface; rather it has straight walls 64
designed to capture the boss 52, and thereby irreversibly lock the sheath
42 in the position concealing the needle 38. It is apparent from an
inspection of FIG. 6 that the sheath 42 can be moved out of the third
position only by breaking or substantially damaging the boss 52.
All components of the above-described combination 30, with the exception of
the metal body of the needle 38, can be manufactured by injection molding
from plastic materials of the type ordinarily used for the manufacture of
hypodermic syringes. Medical grade polypropylene, for example, is suitable
material for the manufacture of the syringe.
The sheath 42, however, can be made of a lower non-medical grade of plastic
because it does not come into contact with medication. In fact, as an
additional novel feature of the present invention, the sheath 42 is made
of a plastic material which melts at substantially lower temperature than
the medical grade plastic of the syringe barrel 32 and plunger 34, and
which does not withstand the temperatures required for heat sterilization
of syringes.
More particularly, in accordance with this feature, the material of the
sheath 42 has a "deflection temperature" below the "deflection
temperature" of the material of the syringe barrel 32 and plunger 34, and
below the autoclaving temperatures normally required in medical practice
to sterilize hypodermic syringes. Deflection temperature of a plastic
material in this regard is understood to mean the temperature at which the
material loses virtually all of its strength at very low stress. Thus, at
temperatures slightly higher than the deflection temperature, the plastic
material deforms, and "melts." Thus, exposing plastic articles to
temperatures above their deflection temperature results in serious
deformation (melting) of the articles.
The materials from which the sheath 42 is made in accordance with this
feature preferably is also reasonably transparent. Acrylic styrene
copolymer having a deflection temperature of 230.degree. F. is eminently
suitable for this purpose. Other suitable plastic materials include
styrene-butadiene (deflect. temp. 158.degree. F.), acrylonitril butadiene
styrene (ABS) (deflect. temp. 170.degree. F.), and an ionomer known under
the trademark SURLYN of Dupont Corporation (deflect. temp. 129.degree. F.)
In this connection, acrylic styrene copolymer, styrene-butadiene and
acrylonitril butadiene styrene are preferred
In light of the foregoing, if one were to attempt to heat sterilize the
hypodermic syringe and needle combination of the present invention for
reuse, the sheath 42 would melt and render the combination 30,
particularly the needle 38, unusable. The just-described feature clearly
reduces even further the potential for abuse of the hypodermic syringe and
needle combination of the present invention.
Although the manner of using the first preferred embodiment 30 of the novel
hypodermic syringe and needle combination of the present invention is
apparent from the foregoing description and drawing figures, for the sake
of further clarity and full disclosure, the steps are summarized as
follows.
Just before use, the tamper evident wrapping seal (not shown) is removed by
a doctor (not shown), nurse (not shown), or patient (not shown) from the
hypodermic syringe and needle combination 30 of the invention. Thereafter,
the cap 46 is removed from the end 44 of the sheath 42, and the sheath 42
is moved upward on the barrel 32, first by dislodging the boss 52 from the
first cavity 54 and thereafter by sliding the boss 52 in the guide channel
48. Just before the boss 52 reaches the end of the guide channel 48, it
snaps into the cavity 60, indicating that the sheath 42 has reached its
second position relative to the barrel 32 and needle 38. The hypodermic
syringe and needle combination 30 is used in this configuration to fill
the barrel 32 with a drug or medication (not shown) and to administer the
medication (not shown) into the patient (not shown). After administration
of the medication, the sheath is moved slightly upward, turned, and
thereafter moved downward relative to the barrel 32 by riding the boss 52
in the guide channel 50, until the boss 52 is captured in the third cavity
62. This locks the sheath 42 in its final position adapted for safe
disposal of the combination 30. Optionally, just before the combination 30
is discarded and as an added safety feature, the cap 46 may be placed back
on the end 44 of the sheath 42.
Apparent advantages of the above-described embodiment 30 include the
excellent protection it affords against accidentally wounding the hands of
doctors, nurses, or other personnel handling the syringe and needle
combination 30, before, and especially after administration of a drug (not
shown) to a patient (not shown), and the built-in safeguard against abuse
or misuse of the syringe and needle combination.
Referring now to FIGS. 12 through 16, a second preferred embodiment 66 of
the invention is shown. The second preferred embodiment 66 is similar in
many respects to the above-described first preferred embodiment 30, and is
therefore described here in less detail. Thus, the second preferred
embodiment 66 of the syringe and needle combination of the invention also
includes a sheath 42 which is mounted to the syringe barrel 32 for
relative motion thereon.
The sheath 42 of the second preferred embodiment 66 includes, on its upper
portion, a plurality of circumferentially and substantially evenly spaced
fingers 68. As is best shown on FIG. 12, the fingers 68 are defined by the
axially disposed slots 70 located in the upper portion of the sheath 42.
Each finger 68 includes an inwardly directed boss or protrusion 52. The
barrel 32 of the second preferred embodiment 66 includes two
circumferential slots or grooves which bear the reference numerals 72 and
74, respectively.
In the second embodiment 66, the sheath 42 has two principal positions
relative to the barrel 32 and needle 38. In the first position, shown on
FIG. 13, the bosses 52 of the fingers 68 engage the lower circumferential
groove 72, and the needle 38 is protected by the sheath 42. In the second
position of the sheath 42, the bosses 52 of the fingers 68 engage the
upper circumferential groove 74, and the needle 38 is exposed. After the
hypodermic syringe and needle combination of the second preferred
embodiment 66 has been used for administering medication, the sheath 42 is
again placed into the first position wherein it covers the needle 38.
FIGS. 17 and 18 disclose a third preferred embodiment 76 which is similar
in construction to the second embodiment 66, but, after the combination
has been used for its intended purpose, permits permanent locking of the
sheath 42 in the position where the needle 38 is covered. This is
accomplished by providing two circumferential grooves 72 and 78 on the
lower portion of the barrel 32. Before use, the camming bosses 52 of the
fingers 68 rest in the circumferential groove 72 from which they are
removed when the sheath 42 is moved upwardly on the barrel 32 to expose
the needle 38. Before the third preferred embodiment 76 is used,
additional square bosses 80 of the fingers 68 rest on the barrel 32, as is
shown on FIG. 17. After use, the sheath 42 is locked into its position to
cover the needle 38 by pushing the sheath 42 on the barrel 32 slightly
below its original first position, whereby the square bosses 80 engage and
lock into the groove 72, and the camming bosses 52 are simply accommodated
in the circumferential groove 78.
FIGS. 19 through 23 disclose yet a fourth preferred embodiment 82 of the
hypodermic syringe and needle combination of the present invention. The
fourth embodiment 82 is similar in many respects to the first preferred
embodiment 30 in that an inwardly directed boss 52 of the sheath 42 is
guided in a guide channel 84 to accomplish the hereinafter-described
functions. More particularly, in the first position of the sheath 42 it
covers and protects the needle 38. In this position, the boss 52 is
disposed in a side arm 86 of the guide channel 84. In order to prepare the
syringe and needle combination 82 for use, the cap 46 is removed and the
sheath 42 is slightly turned relative to the barrel 32 until the boss 52
is located in the main guide channel 84. The sheath 42 is then moved
upward on the barrel 32 to expose the needle 38. After administration of a
drug (not shown) by the combination 82, the sheath 42 is moved downwardly
on the barrel 32, and is thereafter turned so as to guide the boss 52 into
the second side arm 88 of the guide channel 84. After a slight upward
pull, the boss 52 engages and locks into the cavity 90, thereby locking
the sheath 42 into its final position for disposal. In this position the
needle 38 is covered by the sheath 42, but for added safety the cap 46 is
also replaced on the sheath 42.
What has been described above is a novel hypodermic syringe and needle
combination having a movably mounted protective sheath to cover the needle
before and after the use of the syringe and needle for administering drugs
to patients, or in the course of veterinary medicine, drugs to animals.
The novel combination of the present invention offers the advantages of
safety, substantially eliminates the dangers of accidental wounding and
infection of persons by used needles, and significantly reduces the danger
for abuse or misuse of disposable syringes and needles.
Inasmuch as many modifications of the present invention may become readily
apparent to those skilled in the art in light of the foregoing disclosure,
the scope of the present invention should be interpreted solely from the
following claims.
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