Syringe needle abstract
A safety syringe with a needle sleeve is provided. The needle sleeve
is put around a cap of the syringe with a shoulder portion inside
the needle sleeve abutting against a rear flange of the cap, such
that the cap, a hub tightly fitted in the cap, and the needle sleeve
together form a needle sleeve assembly, which allows the hub to
temporarily locate closely before a neck portion of a barrel of
the syringe, so that the syringe may be sterilized under high temperature
without stress deformation and thermal deformation. When the cap
is depressed, the hub and a cannula held thereto are caused to move
backward and be stably retained to the neck portion of the barrel
in an airtight relation. And when the cap is pulled forward again,
it brings the needle sleeve to together separate from the hub to
expose the cannula for injection.
Syringe needle claims
What is claimed is:
1. A safety syringe apparatus comprising: a barrel having a tubular
front neck portion, said front neck portion having an inner wall
inclined radially inward to terminate at a barrel shoulder portion;
a hub having a cannula extending axially therefrom, said hub being
coaxially disposed relative to said front neck portion of said barrel
for slidably engaged displacement relative thereto between first
and second positions, said hub having an axial end portion and a
base section extending axially therefrom, said axial end portion
abutting said inner wall of said front neck portion in said position,
said base section defining an outwardly directed shoulder flange
for retentively engaging said barrel shoulder portion in said second
position; a needle sleeve having open lower and upper end portions
and an intermediate portion extending therebetween, said lower end
portion at least partially ensleeving said barrel front neck portion,
said intermediate portion having an inner surface defining a sleeve
shoulder portion, said needle sleeve being disposed to extend coaxially
about said base section of said hub; and, a cap coupled to said
hub for removably covering said cannula, said cap terminating at
an open end portion engaging said hub, said cap having formed thereon
adjacent said end portion an outwardly directed cap flange, said
cap engaging said needle sleeve in slidably displaceable manner
through said upper end portion of said needle sleeve; said cap being
axially displaceable relative to said needle sleeve in a first direction
to force said hub into said second position, said cap thereafter
being axially displaceable relative to said needle sleeve in a second
direction for removal from said hub; said cap flange engaging said
sleeve shoulder portion to stop said cap displacement relative to
said needle sleeve in said second direction, said needle sleeve
being thereby locked for removal with said cap from said barrel.
2. The safety syringe apparatus as recited in claim 1 wherein said
needle sleeve defines a substantially tubular contour, said inner
surface of said needle sleeve being generally tapered in diametric
extent, said lower end portion being greater in diametric extend
than said upper end portion.
3. The safety syringe apparatus as recited in claim 1 wherein said
barrel shoulder and sleeve shoulder portions each define an annular
surface directed radially inward.
4. The safety syringe apparatus as recited in claim 3 wherein said
shoulder flange and said cap flange each define an annular surface
directed radially outward.
Syringe needle description
BACKGROUND OF THE INVENTION
There are many safety syringes developed particularly to prevent
discarded syringes and/or cannulas from unexpectedly stabbing and
therefore undesirably injuring and infecting other people, including
nursing and cleaning persons. U.S. Pat. Nos. 5562627; 5405327;
5569203; 5899887; 5395346 etc., all disclose syringes having
specially associated hubs and barrels, so that hubs and cannulas
held thereto of used syringes can be pulled back into the barrels
without the risk of unexpectedly stabbing other people.
However, all these safety syringes of prior art developed to improve
conventional syringes have a common problem. That is, although the
hubs of these safety syringes may be stably connected to the barrels
and be pulled back into the latter after the syringes have been
used, the hubs are not always connected to the barrels in an airtight
relation. As it is well-known that, when such safety syringes are
assembled in the manufacturing process thereof, the hubs and the
barrels must first be associated with one another before the syringes
are sterilized, so that the assembled syringes would not be contaminated
after the sterilization due to contact of any part of the syringes.
However, the assembled hubs and barrels are subject to stress deformation
and thermal deformation during the sterilization under high temperature
and such deformation would have adverse influence on the stable
and airtight connection of the hubs to the barrels.
It is therefore tried by the inventor to develop a further improved
safety syringe to eliminate the drawbacks existing in the safety
syringes of prior art.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide a safety
syringe with a needle sleeve that is particularly made to improve
a conventional safety syringe with a retractable hub. The needle
sleeve of the safety syringe of the present invention allows the
syringe to be sterilized with the hub and the barrel thereof in
a contacted but non-engaged state, so that no stress deformation
of the syringe would occur to adversely affect the airtight connection
of the hub to the barrel of the syringe after the sterilization.
Another object of the present invention is to provide a safety
syringe with a needle sleeve, so that the needle sleeve firmly holds
the cap, the hub, and the barrel together to, on the one hand, prevent
the cannula connected to the hub and covered by the cap from contamination
by externally contacting the cannula, and, on the other hand, enable
easy assembling of the hub to the barrel of the safety syringe simply
by depressing the cap. And, the cap can be then pulled forward again
to bring the needle sleeve to together separate from the syringe
to expose the cannula for injection.
BRIEF DESCRIPTION OF THE DRAWINGS
The structure and the technical means adopted by the present invention
to achieve the above and other objects can be best understood by
referring to the following detailed description of the preferred
embodiments and the accompanying drawings, wherein
FIG. 1 is an exploded perspective of a safety syringe with a needle
sleeve according to the present invention;
FIG. 2 is a sectional view of the needle sleeve of the present
invention;
FIG. 3 is an enlarged and fragmentary sectional view of the safety
syringe of the present invention showing the manner of assembling
the hub, the cap, and the needle sleeve, wherein the hub has not
been retained to a neck portion of a barrel of the safety syringe
of the present invention;
FIG. 4 is a sectional view similar to FIG. 3 but with the hub being
retained to the neck portion of the barrel of the safety syringe
of the present invention;
FIG. 5 illustrates the manner of removing the cap and the needle
sleeve from the hub and the barrel of the safety syringe of the
present invention;
FIG. 6 shows the engagement of a plunger of the safety syringe
with the hub when the plunger has been fully pushed forward in the
barrel of the safety syringe; and
FIG. 7 shows the hub and the cannula are pulled backward by the
plunger into the barrel when the cannula has been used.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Please refer to FIG. 1 that is an exploded perspective of a safety
syringe with a needle sleeve according to the present invention.
The safety syringe mainly includes a barrel A, a plunger B slidably
mounted in the barrel A, a hub C connected to a front end of the
barrel A for holding cannula C1 thereto, and a cap D for covering
the cannula C1 and is characterized in a needle sleeve 1 put around
joints of the hub and the barrel and of the hub and the cap, as
can be best seen in FIG. 3.
Please refer to FIG. 2. The needle sleeve 1 is a hollow tube defining
an inner space therein. A front part of the inner space of the needle
sleeve 1 has a reduced inner diameter. And, an inner peripheral
wall 12 of this front part is properly tapered toward a front end
of the safety syringe, that is, an end with the cannula C1. A rear
part of the inner space of the needle sleeve 1 has an expanded inner
diameter relative to the front part, and an inner peripheral wall
13 of the rear part is properly tapered toward the front end of
the safety syringe, too. A first shoulder portion 11 is therefore
formed between the inner peripheral wall 12 of the front part and
the inner peripheral wall 13 of the rear part of the inner space
of the needle sleeve 1.
Please refer to FIGS. 1 and 3. The hub C is formed near a middle
portion thereof with a second shoulder portion C2 and at a rear
portion thereof with engaging holes C3. The barrel A has a diameter-reduced
neck portion A2 that defines a front open end of the barrel A. An
inner peripheral wall A1 of the front to open end of the neck portion
A2 inclines radially inward. And, a third shoulder portion A3 is
formed between the inclined peripheral wall A1 and a straight inner
peripheral wall of the neck portion A2 behind the inner open end
of the neck portion A2. The cap D includes a slightly forward tapered
outer peripheral wall surface D1 and a radially projected flange
D2 around a rear bottom of the tapered outer peripheral wall D1.
In assembling the safety syringe of the present invention, first
extend the hub C and the cannula C1 connected thereto into the cap
D. The cap D is so designated that it has an inner diameter similar
to an outer diameter of a portion of the hub C above the second
shoulder portion C2 so that the hub C could be tightly fitted in
the cap D to form a needle assembly. Thereafter, the needle sleeve
1 is put around the needle assembly from a front end of the cap
D, so that the first shoulder portion 11 inside the needle sleeve
1 abuts on the rear flange D2 of the cap D. At this point, a rear
end portion of the forward tapered outer peripheral wall surface
D1 and the rear flange D2 of the cap D fitly contact with the front
and the rear inner peripheral walls 12 13 of the needle sleeve
1 respectively, with the first shoulder portion 11 abutted against
the flange D2. The needle assembly and the needle sleeve 1 put therearound
therefore form a needle sleeve assembly. As can be clearly seen
from FIG. 3 the hub C is completely covered by the needle sleeve
1 and isolated from external environment and accordingly, any contamination
possibly caused by undesirably contacting the cannula. The needle
sleeve assembly is then assembled to the barrel A by engaging the
inner peripheral wall 13 of the rear part of the needle sleeve 1
with an outer peripheral wall of the reduced neck portion A2 of
the barrel A, as shown in FIG. 3 to form a syringe assembly, that
is, the safety syringe of the present invention. Before being using
to inject a medical liquid, this syringe assembly has a hub C that
has a rear bottom portion contacting with the inclined inner peripheral
wall A1 at the front open end of the neck portion A2 of the barrel
A without being extended into a retained to the neck portion A2.
The syringe assembly is then sterilized under high temperature in
this state.
Since the hub C is not fully extended into and retained to the
neck portion A2 of the barrel A when the syringe assembly is sterilized
under high temperature, there would not be any stress produced at
this sterilization stage. Therefore, any stress deformation and
any thermal deformation of the whole syringe due to such high temperature
sterilization could be avoided.
To use the syringe assembly for injection of any medical liquid,
a user may depress a front end of the cap D, so that the hub C tightly
fitted in the cap D is brought to move downward at the same time.
When the second shoulder portion C2 on the hub C is downward moved
to pass through the radially inward inclined peripheral wall surface
A1 and the third shoulder portion A3 at the front open end of the
neck portion A2 of the barrel A, the hub C would not be able to
be pulled forward again to separate from the barrel A. At this point,
an outer peripheral wall surface of the rear portion of the hub
C behind the second shoulder portion C2 would contact with the straight
inner peripheral wall surface of the neck portion A2 behind the
third shoulder portion A3 in a tight fit relation, as shown in FIG.
4 so that an airtight effect at the joint of the hub C and the
barrel A is accomplished. Finally, the cap D is pulled forward to
expose the cannula C1. When doing so, the rear bottom flange D2
of the cap D would be moved to abut against the first shoulder portion
11 inside the needle sleeve 1 and therefore brings the needle sleeve
1 to separate from the hub C at the same time, as shown in FIG.
5. After the cap D and the needle sleeve 1 have been removed to
expose the cannula C1 the safety syringe of the present invention
is ready for use.
When using the safety syringe of the present invention to inject
a patient with medical liquid, the plunger B is fully pushed forward
in the barrel A until an engaging cone B2 provided at a front end
of the plunger B engages with the engaging holes C3 provided at
the rear portion of the hub C, as shown in FIG. 6. After the injection,
the plunger B may be pulled backward to bring the hub C, which is
now associated with the plunger B, and the cannula C1 that is connected
to the hub C, to move back into the barrel A, as shown in FIG. 7.
The following are some of the advantages of the safety syringe
of the present invention.
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