Medical syringe abstract
A disposable shielded medical syringe wherein the contaminated
needle is connected to a piston slidably mounted in the syringe
barrel. The syringe plunger piston is threadably connectable to
the needle piston for pulling the contaminated needle into the barrel
to the shielded position. The syringe plunger is disconnectable
from the plunger piston after the needle has been moved to the shielded
position and a cap is insertable into the open end of the syringe
barrel to completely enclose the contaminated needle.
Medical syringe claims
We claim:
1. A disposable shielded medical syringe comprising a syringe barrel,
a plunger slidably mounted in said barrel, a piston secured to the
distal end of the plunger and being in sealing, sliding engagement
with the inner wall of the barrel, a second piston slidably mounted
in said barrel and being in sealing, sliding engagement with the
inner wall of the barrel and being positioned between the distal
end portion of the barrel and the plunger piston, a syringe needle
extending outwardly longitudinally of the barrel at the distal end
thereof, means for detachably connecting the syringe needle to said
second piston, means for mechanically connecting said plunger piston
to said means for connecting the syringe needle to said second piston,
said second piston having a configured outer surface cooperating
with a similarly configured inner surface on the distal end of said
barrel, to thereby prevent the second piston from rotating within
the barrel when the needle is being operatively connected thereto
and also preventing the second piston from rotating within the barrel
when the plunger piston is being operatively connected thereto,
and a medicament contained within the barrel between the plunger
piston and the second piston, whereby the medicament is dispensed
through the needle by pushing the plunger inwardly, whereupon the
plunger piston is mechanically connected to the means for connecting
the syringe needle to said second piston, and the second piston
and associated contaminated needle is drawn inwardly to a shielded
position within the barrel by pulling the plunger in a direction
toward the proximate end of the barrel.
2. A disposable shielded medical syringe according to claim 1
wherein the means for connecting the syringe needle to the second
piston comprises, a Luer Lock member operatively connected to said
second piston, said needle having a Luer Lock hub portion, said
needle Luer Lock hub portion being threadably connected to said
Luer Lock member.
3. A disposable shielded medical syringe according to claim 2
wherein the means for mechanically connecting the plunger piston
to the Luer Lock member comprises a threaded projection extending
axially from the plunger piston, and a similarly configured threaded
aperture provided in said Luer Lock member.
4. A disposable shielded medical syringe according to claim 1
wherein a needle cap is insertable into the open end of the barrel
to prevent the contaminated needle from being moved from the retracted,
shielded position outwardly through the open end of the barrel.
5. A disposable shielded medical syringe according to claim 1
wherein spring stop means are mounted on the proximate end portion
of the barrel adapted to be engaged by the syringe piston when fully
retracted to thereby prevent complete removal of the syringe piston
from the barrel.
6. A disposable shielded medical syringe according to claim 1
wherein connecting means are provided between the plunger and plunger
piston, whereby the plunger is disconnected from the plunger piston
after the contaminated needle is moved to the shielded position.
7. A disposable shielded medical syringe comprising a syringe barrel,
a plunger slidably mounted in said barrel, a piston secured to the
distal end of the plunger and being in sealing sliding engagement
with the inner wall of the barrel, a second piston slidably mounted
in said barrel and being in sealing, sliding engagement with the
inner wall of the barrel and being positioned between the distal
end portion of the barrel and the plunger piston, a syringe needle
extending outwardly longitudinally of the barrel at the distal end
thereof, means for connecting the syringe needle to said second
piston, means for mechanically connecting said plunger piston to
said means for connecting the syringe needle to said second piston,
and a medicament contained within the barrel between the plunger
piston and the second piston, said second piston having a polygonal
outer surface, the distal end portion of the barrel having a polygonal
inner surface cooperating with the polygonal outer surface on the
second piston, whereby the second piston is prevented from rotating
within the barrel when the needle is being operatively connected
to said second piston.
8. A disposable shielded medical syringe of the type wherein the
syringe needle is retracted into the syringe barrel through the
open end of the barrel, the improvement comprising spring stop means
mounted on the proximate end portion of the barrel adapted to be
engaged by the syringe piston when fully retracted to thereby prevent
complete removal of the syringe from the barrel, the syringe piston
including a plunger having a threaded stem portion threadably mounted
in a threaded hub portion on the piston whereby the plunger can
be disconnected from the piston when the piston has been moved to
the retracted position, radially extending arms on said hub portion,
portions of the spring stop means being engageable with said arms
to thereby prevent rotation of the piston during the disconnecting
of the plunger therefrom.
9. A disposable shielded medical syringe comprising a syringe barrel,
a plunger slidably mounted in said barrel, a piston secured to the
distal end of the plunger and being in sealing sliding engagement
with the inner wall of the barrel, a second piston slidably mounted
in said barrel and being in sealing, sliding engagement with the
inner wall of the barrel and being positioned between the distal
end of the barrel and the plunger piston, a syringe needle extending
outwardly of the barrel at the distal end thereof, means for connecting
the syringe needle to said second piston, and a medicament contained
within the barrel between the plunger piston and the second piston,
said second piston having a polygonal outer surface, the distal
end portion of the barrel having a polygonal inner surface cooperating
with the polygonal outer surface on the second piston, whereby the
second piston is prevented from rotating within the barrel when
the needle is being operatively connected to said second piston.
Medical syringe description
CROSS-REFERENCE TO RELATED APPLICATION
This application relates to a disposable shielded medical syringe
of the type disclosed in applicants' copending application Ser.
No. 07/232775 filed Aug. 16 1988 entitled DISPOSABLE SHIELDED
MEDICAL SYRINGE.
BACKGROUND OF THE INVENTION
Medical personnel have to exercise the utmost of care when using
conventional syringes so as not to be accidentally punctured by
a contaminated syringe needle resulting in possible exposure to
infectious diseases, such as acquired immune deficiency syndrome
(AIDS) or serum hepatitis when injecting a medicament into a patient.
While various safeguards have been provided, such as protective
caps for covering a used needle and sharps containers for the disposal
of the used needle, it has been found that the chance of accidental
puncture is most likely to occur during the manipulation of the
syringe to either cap the needle or inverting the used needle into
the sharps container.
In an effort to improve the safeguards for used syringe needles,
it has been proposed to provide the syringe with a sleeve slidably
mounted on the syringe barrel and movable from a retracted position
on the syringe barrel to an extended position at the distal end
of the barrel, to thereby provide a shield surrounding the used
needle. The sleeve is releasably held in the retracted and extended
positions by detents which are manually actuated by the user. These
sleeve-type shields have not proven entirely satisfactory due, mainly,
to the manual dexterity required by the user to release one detent
for sliding the sleeve to the needle protecting position and then
to actuate another detent for holding the sleeve in the extended
position.
In order to overcome the disadvantages experienced in hitherto
employed shielded medical syringes, the disposable shielded medical
syringe of the present invention has been devised which comprises,
essentially, a syringe barrel including a plunger threadably connected
to a piston on the end thereof, the piston being slidably mounted
in the barrel in sealing engagement with the barrel side wall. The
syringe needle is connected to a second piston assembly slidably
mounted with the barrel, in sealing engagement with the barrel side
wall and located between the distal end of the barrel and the plunger
piston. The plunger piston is adapted to be threadably connected
to the needle piston assembly for withdrawing the contaminated needle
into the syringe barrel. By this construction and arrangement, medicament
is dispensed from the syringe by pushing the plunger toward the
distal end of the barrel. After the medicament has been dispensed,
the plunger is rotated to threadably couple the plunger piston to
the needle piston assembly. The plunger is then pulled toward the
proximate end of the barrel, thereby causing the contaminated needle
and associated piston assembly to be withdrawn to a shielded position
within the syringe barrel. The plunger is then disconnected from
its piston and discarded, to thereby prevent the needle and associated
piston assembly from being pushed once again toward the distal end
of the barrel.
To complete the shielding of the used needle, a cap or scabbard
is inserted into the distal end of the syringe barrel.
A spring clip is mounted on the proximate end portion of the syringe
barrel providing a stop member to prevent the syringe plunger from
being pulled completely out of the barrel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of a syringe needle and cap or scabbard;
FIG. 2 is a sectional view of the cap taken along line 2--of FIG.
1 showing the cap mounted on the needle;
FIG. 3 is an exploded view of the syringe of the present invention
without the needle and cap assembly illustrated in FIGS. 1 and 2:
FIG. 4 is a plan view of a spring clip employed as a stop member
in the syringe barrel to prevent complete withdrawal of the syringe
plunger from the barrel;
FIG. 5 is an enlarged fragmentary, sectional view of the syringe
taken along line 5--5 of FIG. 6;
FIG. 6 is a fragmentary top plan view showing the distal end portion
of the syringe barrel and associated needle;
FIG. 7 is a sectional view illustrating the relative positions
of the plunger piston and needle piston assembly when dispensing
medicament from the syringe;
FIG. 8 is a sectional view of the relative positions of the plunger
piston and needle piston assembly during the coupling of the pistons
to each other;
FIG. 9 is a sectional view of the needle piston assembly and plunger
piston moved to the shielded position within the syringe barrel
with the plunger disconnected therefrom, and the cap inserted into
the open end of the barrel; and
FIG. 10 is a view taken along line 10--10 of FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings and more particularly to FIGS. 1 and
2 a conventional syringe needle 1 is shown having a Luer Lock hub
portion 2 having lands 3. The needle is provided with a cap or cover
4 slidably mounted on the hub portion 2 of the needle, the lands
3 of the needle hub being engageable with a rib integral with the
interior wall of the cap 4. The exterior wall of the cap 4 is provided
with integral lands 6 and a flange portion 7.
FIGS. 3 and 5 illustrate the components of the syringe assembly
of the present invention to which the syringe needle 1 and associated
cap 4 of FIGS. 1 and 2 are adapted to be connected. The syringe
assembly comprises a cylinder or barrel 8 having a hollow piston
9 slidably mounted therein in sealing engagement with the interior
wall of the barrel. The piston 9 carries a Luer Lock member 10 into
which the needle hub portion 2 is threadably secured as at 11. The
member 10 ils provided with an annular flange 12 which is received
within a similarly configured groove 13 provided in the end portion
of the piston 9 to thereby sealably secure the Luer Lock member
10 within the piston 9. To prevent rotation of the Luer Lock member
10 relative to the piston 9 during the connection of the needle
1 thereto, the piston 9 is provided with an annular rim 14 extending
into a similarly configured recess 15 provided in the oppositely
extending face of the Luer Lock member 10. The annular rim is interrupted
as at 14a to provide a radially extending recess for receiving a
radially extending rib 15 a provided in the recess 15. The piston
9 tapers inwardly and is provided with a polygonal outer surface
9a conforming to a conical portion 16 on the distal end of the cylinder
8 having a polygonal inner surface 16a. By this construction and
arrangement, the mating or cooperating polygonal surfaces 9a and
16a prevent rotation of the piston 9 when coupling the plunger piston
thereto, to be described more fully hereinafter. The conical portion
16 of the barrel 8 is also provided with an opening 17 on the end
thereof through which the needle 1 and hub 2 extend when connected
to the Luer Lock member 10 as shown in FIG. 5.
To complete the structure of the syringe assembly of the present
invention, a plunger 18 having a piston 19 on the end thereof is
slidably mounted within the proximate end portion of the barrel
8 the piston 19 having a projection 20 extending axially therefrom
and provided with threads 20a receivable within a similarly configured
aperture 21 in the Luer Lock member 10 having a cooperating thread
portion 21a, whereby the plunger piston 19 can be threadably connected
to the syringe needle piston assembly.
As will be seen in FIGS. 3 and 10 the proximate end portion of
the barrel wall is provided with a plurality of apertures 22 for
receiving inwardly extending finger portions 23 carried by a spring
clip 24 mounted on the exterior surface of the barrel wall, whereby
the spring clip fingers 23 are adapted to engage the plunger flange
25 adjacent the piston 19 to thereby prevent complete withdrawal
of the plunger 18 from the barrel 8.
Referring to FIGS. 8 and 10 it will be seen that the plunger 18
is cruciform in cross-section having radially extending arm portions
18a, 18b. At the proximate end portion of the plunger 18 the radial
dimension of the arm portions is reduced as at 26 whereby the finger
portions 23 of the spring clip 24 are precluded from preventing
rotation of the plunger 18 when connecting the plunger piston 19
to the Luer Lock member 10 and associated piston 9.
To further enhance the disposability of the shielded medical syringe
of the present invention, the distal end portion of the plunger
18 is interrupted as at 27 and the hub portion 28 FIG. 10 is provided
with internal threads adapted to receive a threaded stem 29 on the
end of the plunger 18 whereby, after the needle 1 and associated
piston have been pulled to the shielded position as shown in FIG.
9 the plunger 18 is rotated, to thereby disconnect the plunger
18 from the piston 19. When in the retracted position, the spring
fingers 23 will abut the side faces of the arms 18a and 18b to prevent
the piston 19 from rotating while the plunger 18 is being disconnected
therefrom.
The contaminated needle 1 is completely enclosed by inserting the
cap 4 in an upside-down manner through the barrel opening 17. The
cap flange 7 prevents the cap from being inserted completely into
the barrel 8 and the ends of the cap lands 6 engage the portion
of the end wall of the distal end of the barrel surrounding the
aperture 17. To facilitate the insertion of the cap 4 through the
barrel opening 17 the cap lands 6 can be resilient so that they
can be squeezed or compressed while being inserted through the opening,
or alternatively, if the lands 6 are rigid, the portion of the end
wall of the distal end of the barrel surrounding the aperture 17
can be made resilient, to thereby expand during the insertion of
the cap 4.
In the operation of the disposable shielded medical syringe of
the present invention, the medicament is dispensed from the barrel
8 through the Luer Lock member 10 and needle 1 by pushing the plunger
18 inwardly of the barrel as shown in FIG. 7. After the medicament
has been dispensed from the syringe, the medical person will wrap
one hand around the barrel 8 remote from the contaminated needle
1 behind the finger protecting flange 30 provided on the exterior
surface of the barrel, and with the other hand rotate the plunger
18 to thereby threadably couple the plunger piston 19 to the Luer
Lock member 10 and associated piston 9. The plunger 18 and associated
pistons 9 and 19 are then pulled inwardly of the syringe barrel
8 as shown in FIG. 9. The plunger 18 is then disconnected from
the piston 19 and discarded, and the cap 4 is inserted into the
barrel opening 17 as described hereinabove. By disconnecting the
plunger 18 from the piston 19 the contaminated needle 1 cannot
be inadvertently pushed in the opposite direction through the barrel
opening 17 in the event that the cap 4 has not been placed thereon.
From the above description, it will be readily apparent to those
skilled in the art that the disposable shielded medical syringe
of the present invention provides an improved disposable shielded
syringe needle requiring minimal manipulation to move the contaminated
needle to the shielded position, and by providing the feature of
disconnecting the plunger from the plunger piston, together with
the placement of the cap on the open end of the barrel, there is
provided an improved safeguard for medical personnel against exposure
to infectious diseases.
It is to be understood that the form of the invention herewith
shown and described is to be taken as a preferred example of the
same, and that various changes in the shape, size and arrangement
of parts may be resorted to, without departing from the spirit of
the invention or scope of the subjoined claims. |