Abstrict A prefilled disposable syringe having a barrel, hub, and needle
with a plunger rod/protector attached to the outer surface of the
barrel near the hub by flexible protrusions from the inner surface
of the plunger rod/protector. The flexible protrusions frictionally
engage the outer surface.
Claims What is claimed is:
1. A prefilled disposable syringe comprising:
(a) an assembly comprising a hub, a needle rigidly attached to
said hub, and a barrel having a hollow bore, said hollow bore in
fluid communication with said needle, said barrel having an outer
surface near said hub,
(b) a stopper disposed in said bore having first engagement means,
(c) medicament disposed in said bore between said stopper and said
needle, and
(d) a plunger rod/protector adapted to enclose said needle, hub
and outer surface comprising a narrow portion having a cavity for
said needle, said narrow portion capable of fitting within said
hollow bore; attachment means for attaching said plunger rod/protector
to said outer surface at a first end of said narrow portion comprising
an inner surface adapted to enclose said outer surface and flexible
means protruding from said inner surface to grip said outer surface;
and a second engagement means at a second end of said narrow portion
adpated to engage said first engagement means, wherein said plunger
rod/protector is adapted to securely protect said needle during
transit and storage and to act as a plunger rod after engagement
of said firsrt and second engagement means.
2. The syringe of claim 1 wherein said barrel is glass.
3. The syringe of claim 2 wherein said flexible means comprise
a plurality at flexible fins disposed substantially axially to said
needle.
4. The syringe of claim 3 further comprising an elastomeric needle
sheath adpated to cover and seal said needle and to attach to said
hub by frictional fit at an open end, said sheath having a shoulder
at said open end, and wherein said plunger rod/protector is adapted
to cover said sheath and has a cavity between said narrow portion
and said attachment means large enough to cover said shoulder without
gripping said shoulder.
5. The syringe of claim 4 wherein said plunger rod/protector is
constructed of material selected from the group consisting of polypropylene,
polyethylene, polyamide, polyacrylonitrile, and copolymers thereof.
6. The syringe of claim 5 wherein said fins have depth perpendicular
to said inner surface of from 0.14" to 0.17" and thickness
of from 0.018" to 0.027".
7. The syringe of claim 6 wherein said inner surface has at least
four fins disposed at substantially equal distance around said inner
surface obliquely to said inner surface.
8. The syringe of claim 7 wherein said inner surface is approximately
circular, and wherein said fins protrude from said inner surface
such that an outer angle included between each of said fins and
a radius of the circle drawn through the tip of each fin is about
60.degree..
9. A disposable syringe suitable for prefilling comprising:
a. an assembly comprising a hub, a needle rigidly attached to said
hub, and a barrel having a hollow bore, said hollow bore in fluid
communication with said needle, said barrel having an outer surface
near said hub,
b. a plunger rod/protector adapted to enclose said needle, hub,
and outer surface, comprising a narrow portion having a cavity for
said needle, said narrow portion capable of fitting within said
hollow bore, attachment means for attaching said plunger rod/protector
to said outer surface at a first end of said narrow portion comprising
an inner surface adapted to enclose said outer surface and flexible
means protruding from said inner surface to grip said outer surface;
and an engagement means at a second end of said narrow portion.
10. A plunger rod/protector comprising a narrow portion having
an outer surface and a cavity, attachment means at a first end of
said narrow portion comprising an enlarged inner surface, said inner
surface being larger than said outer surface of said narrow portion
and flexible means protruding from said inner surface adapted for
attachment to an outer surface of a syringe barrel; and an engagement
means at a second end of said narrow portion.
11. The plunger rod/protector of claim 10 wherein said flexible
means comprises a plurality of flexible fins disposed axially to
said hollow portion.
12. The plunger rod/protector of claim 11 further comprising a
cavity between said narrow portion and said attachment means having
size intermediate the size of said attachment means and the cavity
in said narrow portion.
13. The plunger rod/protector of claim 12 constructed of material
selected from the group consisting of polypropylene, polyethylene,
polyamide, polyacylonitrite, and copolymers thereof.
14. The plunger/rod protector of claim 13 wherein said fins have
depth perpendicular to said inner surface of from 0.14" to
0.17" and thickness of from 0.018" to 0.027".
15. The plunger rod/protector of claim 14 wherein said inner surface
has at least 4 fins disposed at substantially equal distance around
said inner surface, obliquely to said inner surface.
16. The plunger rod/protector of claim 15 wherein said inner surface
is approximately circular, and wherein said fins protrude from said
inner surface such that an outer angle included between each of
said fins and a radius of the circle drawn through the tip of each
fin is about 60.degree..
Description BACKGROUND
This invention relates to disposable syringes, more specifically,
to syringes having a needle protector capable of functioning as
a plunger rod after it has been removed from its position protectng
the needle and attached to a stopper disposed in the syringe's barrel.
The present invention has several advantages over prior-art syringes
wherein the plunger rod/protector is attached at the syringe hub
by a force fit over a sheath. The needle is far less likely to be
bent during shipment and handling. The syringe barrel is protected
at the place where it is most likely to break. The needle sheath
will not be removed accidentally when the plunger rod/protector
is removed from its protective position. The plunger rod/protector
fits well despite normal dimensional variation in a glass syringe
barrel.
One aspect of the present invention is a prefilled disposable syringe
comprising:
(a) an assembly having a hub, a needle rigidly attached to the
hub, and a barrel having a hollow bore and an outer surface near
the hub,
(b) a stopper disposed in the bore having first engagement means,
(c) medicament disposed in the bore between the stopper and the
needle, and
(d) a plunger rod/protector adapted to enclose the needle, hub
and outer surface comprising a narrow portion having a cavity for
the needle, the narrow portion capable of fitting within the hollow
bore; attachment means for attaching the plunger rod/protector to
the outer surface at a first end of the narrow portion comprising
an inner surface adapted to enclose the outer surface and flexible
means protruding from the inner surface to grip the outer surface;
and a second engagement means at a second end of the narrow portion
adapted to engage the first engagement means, wherein the plunger
rod/protector is adapted to securely protect the needle during transit
and storage and to act as a plunger rod after engagement of the
first and second engagement means.
Other aspects of the invention comprise a syringe suitable for
prefilling and a plunger rod/protector.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross-sectional view of a prefilled disposable
syringe in accordance with the invention with the plunger rod/protector
and needle sheath shown separated.
FIG. 2 is a longitudinal cross-sectional view of the syringe of
FIG. 1 with the plunger rod/protector and needle sheath attached.
FIG. 3 is a partial cross-sectional view of a preferred embodiment
of a plunger rod/protector in accordance with the invention taken
in the longitudinal direction.
FIG. 4 is a view of the plunger rod/protector of FIG. 3 taken along
lines 4--4.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 assembly 1 comprises barrel 2 preferably
made of glass for long term storage, integral hub 3 and needle
4 rigidly affixed to hub 3.
Barrel 2 has hollow bore 5 in fluid communication with the needle.
Medicament 5A is disposed in the hollow bore between the needle
and stopper 8. Stopper 8 has a first engagement means 11 preferably
an inner thread. Barrel 2 has outer surface 6 near hub 3.
A plunger rod/protector 12 is adapted to enclose needle 4 hub
3 and outer surface 6 during shipment and storage. Plunger rod/protector
12 has a narrow portion 9 having a cavity 10 for needle 4. The narrow
portion is capable of fitting within hollow bore 5.
At a first end of narrow portion 9 of plunger rod/protector 12
there is located attachment means 14 for attaching the plunger rod/protector
to outer surface 6. Attachment means 14 comprises an inner surface
15 adapted to enclose outer surface 6 and flexible means 16 protruding
from the inner surface. At a second end of the narrow portion of
plunger rod/protector 12 there is located a second engagement means
13 adapted to engage first engagement means 11.
Preferably plunger rod/protector 12 is a molded plastic material
such as polypropylene, polyethylene, polyamide, polyacrylonitrile,
or copolymers thereof. Preferably the mold used to cast the plunger
rod/protector has a central rod affixed at both ends to shape cavity
10. This way the rod cannot flex during casting, causing the cavity
to be eccentric. This method of casting produces an inner bore 13A
in second engagement means 13.
To maintain sterility and seal needle 4 it is preferable to cover
and seal needle 4 with elastomeric needle sheath 17. A needle sheath
normally has a shoulder 17A located at its open end.
FIG. 2 shows the syringe completely assembled and ready for shipment
and long term storage. Elastomeric sheath 17 has been placed over
needle 4 and frictionally attached to hub 3 at the sheath's open
end. Plunger rod/protector 12 covers the needle, hub, sheath and
outer surface 6. When plunger rod/protector 12 is so positioned,
flexible protrusions 16 flex slightly to frictionally engage outer
surface 6. Plunger rod/protector 12 has a cavity 7 between narrow
portion 9 and attachment means 14 large enough so that the plunger
rod/protector will not grip shoulder 17A when positioned.
To use the prefilled disposable syringe of FIG. 2 the operator
removes plunger rod/protector 12 from its position covering the
needle and engages engagement means 11 and 13. Next sheath 17 is
removed and the injection is administered in the usual manner with
plunger rod/protector 12 acting as a plunger rod for stopper 8.
FIG. 3 is a partial longitudinal cross-sectional view of a preferred
embodiment of a plunger rod/protector in accordance with the invention.
FIG. 4 is a view of FIG. 3 taken along lines 4--4. It is preferred
that the outer surface of the barrel and inner surface 15 be substantially
circular, but other shapes are acceptable. In FIGS. 3 and 4 the
flexible means are flexible fins 16A disposed substantially axially
to the needle (not shown). Fins 16A have rounded corners 18 on their
extremity near the end of the plunger rod/protector for easier attachment
to the outer surface of the barrel. Preferably the fins have depth
19 perpendicular to inner surface 15 of from about 0.14" to
0.17" (3.56 to 4.32 mm) with about 0.15" to 0.16"
(3.81 to 4.06 mm) being most preferred. If the shield is made of
plastic, it is preferable that the fins have thickness 23 of about
0.018" to 0.027", (0.46 to 0.69 mm) preferably about 0.022"
to 0.025". (0.56 to 0.64 mm). It is especially preferred that
thickness 23 increase gradually from about 0.02" (0.51 mm)
at rounded corner 18 to about 0.025" (0.64 mm) at the end of
fin 16A nearest to the cavity. Surprisingly, fins made to the preferred
dimensions are easy to make, hold snugly, but are easy to disengage
when desired, even after long term storage.
The length of fins 16A, measured in a direction parallel to the
longitudinal axis of the syringe should be from 0.3" to 0.5"
(7.62 to 12.7 mm) with about 0.375" (9.53 mm) being most preferred.
In FIG. 4 inner surface 15 is approximately circular. The outer
surface of the barrel, shown in phantom having diameter 21 may
be circular. Fins 16A are disposed in a preferred manner at equal
distance around inner surface 15. The number of fins must be at
least one, preferably at least four, with four being most preferred.
Angle 20 the outer angle included between each fin and a radius
drawn through the tip of each fin, may vary between 0.degree. to
90.degree., with about 60.degree. being preferred. In this instance,
it is preferred that the diameter 21 of the outer surface of the
barrel be about 0.425" (10.8 mm), and that diameter 22 of a
circle connecting the inner most portion of the fins be about 0.38"
to 0.400" (9.65 to 10.16 mm).
This invention has several advantages over prior art plunger rod/protectors
that attach to the hub by an interference fit over the sheath. First,
with the plunger rod/protector of this invention attached, the needle
is far less likely to be accidently bent during shipment and handling.
Secondly, with glass barrels, which are preferred for long term
storage, the plunger rod/protector protects the barrel at the place
where breakage is most likely to occur, that is, near the hub.
Frequently, to save time, it is desirable to remove the plunger
rod/protector and engage it with the stopper before the operator
(for example, a doctor or nurse) is ready to administer the injection.
In a small percentage of cases, the prior art plunger rod/protector
will pull the sheath from the needle when the plunger rod/protector
is removed, thereby prematurely unsealing the needle, compromising
sterility, and creating a danger of an exposed needle. Since the
plunger rod/protector of the present invention does not attach by
an interference fit over the sheath, the sheath will not be inadvertently
removed when the plunger rod/protector is removed.
In a small percentage of cases, the prior art glass-covered-by-rubber-covered-by-plastic
fit is too loose because of variation in size, particularly in the
size of the glass hub. Glass is difficult to cast to close tolerance.
The loose fitting plunger rod/protectors tend to slip off during
shipment and handling. The flexible fins of the present invention
are able to firmly attach directly to the glass surface, despite
normal variations in the outer diameter of the barrel.
The present invention accomplishes all these advantages without
using a special adapter on the barrel and without causing difficulty
in removing the plunger rod/protector from its position covering
the needle.
In addition to the prefilled, disposable syringe previously described,
other embodiments of the invention that may find a commercial market
are a disposable syringe suitable for prefilling comprising an assembly
of hub, barrel and needle and a plunger rod/protector. The buyer
of such syringe, who would furnish the medicament and stopper, would
sterilize and prefill the syringe.
Furthermore, the plunger rod/protector of the present invention,
by itself, may prove to be a salable quantity to a buyer who would
supply the medicament, stopper and barrel-hub-needle assembly. Such
a plunger rod protector should have an inner surface from which
flexible means protrude that is larger than the outer surface of
the narrow portion, so that attachment may be made to the barrel
of a syringe for maximum protection.
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