Safety syringe abstract
A retractable safety syringe consists of a syringe barrel, a needle
mount, a plunger rod and a needle. The needle mount is integrated
with an outer hub and an inner hub having a plurality equal-spaced
spring clamps formed at a lower end thereof. The plunger rod has
a plunger formed with a plunger crown with a cone-shaped tip end
portion formed on a top thereof and a neck portion formed between
the tip end portion and the plunger crown. When the plunger rod
is fully extended into the syringe barrel, the tip end portion is
inserted into the lower end of the needle mount and the neck portion
is clamped by the spring clamps. The needle is able to be retracted
into the syringe barrel after finishing an injection procedure.
Safety syringe claims
What is claimed is:
1. A retractable safety syringe comprising:
a syringe barrel (10) having a fixing hole (12) defined in an upper
end thereof and a thumb press (16) formed at a lower end thereof;
a needle mount (20) assembled in the fixing hole (12) and retained
at the upper end of the syringe barrel (10), and integrally formed
with an outer hub (22) and an inner hub (24), wherein the inner
hub (24) has a fluid passage defined in a center thereof and a plurality
of equal-spaced spring clamps (240) formed around a lower end of
the fluid passage and extending in an inclined direction towards
an upper end of the fluid passage;
a plunger rod (30) consisting of a rod (31) and a plunger (32)
detachably connected at an upper end of the rod (31), wherein the
plunger (32) has a plunger crown (322), a cone-shaped tip end portion
(324) formed on a top of the plunger crown (322), and a neck portion
(326) formed between the tip end portion (324) and the plunger crown
(322);
a needle (40) including a connecting portion (41) and a needle
cannula (42);
whereby when the plunger rod (30) is completely extended into the
syringe barrel (10), the tip end portion (324) is inserted into
the fluid passage of the needle mount (20), the neck portion (326)
is clamped by the plurality of spring clamps (240), therefore, the
medicine fluid is able to flow over gaps between each two adjacent
spring clamps (240) toward the needle (40), and then the needle
(40) and the needle mount (20) are connected with the plunger rod
(30) and retractable with the plunger rod (30).
2. The retractable safety syringe as claimed in claim 1 wherein
the outer hub (22) has a female thread (222) formed around an internal
surface thereof, the connecting portion of the needle (40) is formed
with a male thread corresponding to the female thread (222) of the
outer hub (22).
3. The retractable safety syringe as claimed in claim 1 wherein
the outer hub (22) has a plurality of notches (220) defined around
an upper end thereof.
4. The retractable safety syringe as claimed in claim 1 wherein
the outer hub (22) has a plurality of chamfers (220') formed around
an external surface thereof.
5. The retractable safety syringe as claimed in claim 1 wherein
the syringe barrel (10) has a retaining edge (14) integrated around
an internal surface near the upper end thereof, the needle mount
(20) is assembled in the fixing hole (12) and limited by the retaining
edge (14).
6. The retractable safety syringe as claimed in claim 1 wherein
the syringe barrel (10) has an annular retaining groove (18) defined
around the internal surface near the lower end thereof, when the
plunger rod (30) is retracted, a peripheral edge of the plunger
crown (322) is limited by the retaining groove (18) within the syringe
barrel (10).
7. The retractable safety syringe as claimed in claim 1 wherein
the rod (31) has a joint block (304) formed at an upper end thereof,
and the plunger (32) has a joint groove (320) defined in a lower
end thereof to receive the joint block (304) detachably fitted therein.
Safety syringe description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a retractable safety syringe having
a simple structure, which allows ready assembly and safe use and
disposal of the syringe so as to prohibit re-use of the syringe.
2. Description of Related Art
Hypodermic syringes are used to deliver medicine fluids in a safe
and hygienic manner to patients. However it is found that for various
reasons some syringes are re-used and this can result in transfer
of diseases to the people injected with the re-used syringes. Thus
there are various single-use-only safety syringes designed and produced
to enable users to readily operate and dispose the syringes after
finishing an injection procedure. The conventional safety syringe
comprises a retractable needle which allows the needle to be connected
with the plunger rod and retracted into the syringe barrel after
finishing of the injection procedure.
However, the conventional safety retractable syringes still have
some disadvantages which are as follow.
1. Most of the conventional retractable safety syringes are difficult
to use due to their complex structure and multi-components configuration.
The complex structure of the conventional syringe also decreases
the efficiency of manufacturing and increases the manufacturing
costs.
2. Some conventional syringes still have medicine residue in the
syringe barrel when the plunger rod is fully extended into the syringe
barrel, so that the needle is not properly connected with the plunger
rod, which results in that the needle can not be retracted into
the syringe barrel.
3. Also because of the complicated structure of some conventional
syringes, the medicine fluid is not able to directly flow from the
barrel towards the needle of the syringe, whereby some air bubbles
occur in the medicine fluid. These bubbles can be harmful to a patient
who may already be in poor health.
Therefore, it is an objective of the invention to provide an improved
single-use-only and disposable retractable safety syringe to mitigate
and/or obviate the aforementioned problems.
SUMMARY OF THE INVENTION
The main object of the present invention is to provide an improved
retractable safety syringe comprising a needle mount fixed at an
upper end of a syringe barrel, a plunger rod movably fitted in the
syringe barrel and a needle fixed on the needle mount. Wherein the
needle mount is integrated with an outer hub and an inner hub, the
inner hub has a plurality equal-spaced spring clamps formed at a
lower end of a fluid passage defined in a center thereof. The plunger
rod consists of a rod and a plunger detachably connected at an upper
end of the rod. The plunger is formed with a plunger crown having
a cone-shaped tip end portion formed on a top thereof and a neck
portion formed between the tip end portion and the plunger crown.
When the plunger rod is fully fitted into the syringe barrel, the
tip end portion is inserted into the fluid passage, and the neck
portion is clamped by the spring clamps. The medicine fluid retained
in the syringe barrel is able to flow over gaps between each two
adjacent spring clamps, therefore the medicine fluid retention in
the syringe is minimized, and the needle and needle mount are able
to be retracted into the syringe barrel after finishing an injection
procedure.
A further object of the invention is to provide an improved retractable
safety syringe having a configuration feature that ensures ready
assembly and use of the syringe.
Yet another object of the invention is to provide an improved retractable
safety syringe having a simple structure, which enables the medicine
fluid to directly flow in a substantially direct way from the syringe
barrel over the fluid passage towards the needle.
Other objects, advantages and novel features of the invention will
become more apparent from the following detailed description when
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a first embodiment of
a retractable safety syringe in accordance with the invention;
FIG. 2 is a cross sectional assembly view of the first embodiment
of the retractable safety syringe in accordance with the invention;
FIG. 3 is an exploded perspective view of a second embodiment of
the retractable safety syringe in accordance with the invention;
FIG. 4 is a cross sectional assembly view of the second embodiment
of the retractable safety syringe in accordance with the invention;
and
FIGS. 5 6 and 7 are schematic operation views of the retractable
safety syringe in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIGS. 1 and 2 a first embodiment of a retractable
safety syringe in accordance with the invention is shown. The retractable
safety syringe comprises a syringe barrel (10) for receiving of
medicine fluid, a needle mount (20) securely assembled at an upper
end of the syringe barrel (10), a plunger rod (30) movably fitted
in the syringe barrel (10), and a needle (40) fixed on the needle
mount (20).
The syringe barrel (10) is a tubular member having a fixing hole
(12) defined in an upper end thereof, a retaining edge (14) integrated
around an internal surface near the upper end thereof, a thumb press
(16) formed at a lower end thereof, and an annular retaining groove
(18) defined around the internal surface near the lower end thereof
The needle mount (20) is assembled in the fixing hole (12) of the
syringe barrel (10) and limited by the retaining edge (14). The
needle mount (20) has an outer hub (22) and an inner hub (24) integrally
formed therewith, wherein the outer hub (22) has an upper end thereof
defined with a plurality of notches (220), and an internal surface
thereof formed with a female thread (222). The inner hub (24) is
defined with a fluid passage in a center thereof and further has
a plurality of equal-spaced spring clamps (240) integrated at a
lower end of the fluid passage and extending in an inclined way
toward an upper end of the fluid passage.
The plunger rod (30) consists of a rod (31) and a plunger (32)
detachably connected at an upper end of the rod (31). The rod (31)
has a joint block (304) formed at an upper end thereof, and a press
plate (302) integrated at a lower end thereof. The plunger (32)
has a joint groove (320) defined in a lower end thereof to receive
the joint block (304) of the rod (31) detachably fitted therein,
and a plunger crown (322) formed at an upper end thereof. The plunger
(32) further has a cone-shaped tip end portion (324) formed on a
top of the plunger crown (322), and a neck portion (326) formed
between the tip end portion (324) and the plunger crown (322).
The needle (40) includes a connecting portion (41) and a needle
cannula (42). The connecting portion (41) of the needle (40) has
a male thread (402) formed therearound corresponding to the female
thread (222) formed around the internal surface of the outer hub
(22) of the needle mount (20), whereby the needle (40) is threadingly
engaged on the needle mount (20). The plurality of notches (220)
formed around the outer hub (22) is intended to facilitate positioning
of the needle mount (20) to be properly positioned in a fixture
of an assembly line for production of the syringe.
As shown in FIGS. 3 and 4 a second practicable embodiment of the
invention has a structure basically in the same principal as the
first embodiment of the retractable safety syringe. In the second
embodiment, instead of the plurality of notches (220), the outer
hub (22) of the needle mount (20) of the syringe has a plurality
of chamfers (220') formed around an external surface thereof. The
plurality of chamfers (220') is also intended to facilitate positioning
of the needle mount (20) in the fixture of the assembly line.
Now with reference to FIGS. 5 6 and 7 when the plunger rod (30)
is moved from the lower end to the upper end of the syringe barrel
(10), because the plunger crown (322) is particularly made of an
elastic material, a peripheral edge of the plunger crown (322) abuts
tightly against the internal surface of the syringe barrel (10).
Then the cone-shaped tip end portion (324) is inserted into the
fluid passage of the needle mount (20), because there are gaps defined
between each two adjacent spring clamps (240), the medicine fluid
retained in the syringe barrel (10) is still able to flow over the
gaps of the spring clamps (240) towards the needle (40). The spring
clamps (240) are first pressed outward by the cone-shaped tip end
portion (324) to let the tip end portion (324) pass therethrough,
and then spring inwardly to clamp the neck portion (326) so as to
prohibit the tip end portion (324) from disengagement from the spring
clamps (240). After finishing an injection procedure, a user can
readily retract the plunger rod (30), then the needle (40) and the
needle mount (20) are together retracted into the syringe barrel
(10). When the plunger crown (322) moves up to the annular retaining
groove (18), the peripheral edge of the plunger crown (322) is extended
outwardly by its resilient force and limited in the retaining groove
(18), so that the needle (40) and the plunger (32) are retained
within the syringe barrel (10). Finally the rod (31) is detached
from the plunger (32), and the used syringe of the invention can
be safely disposed without fear of it being reused.
The retractable safety syringe of the invention has following advantages:
1. The structure of the retractable safety syringe is simple, whereby
the medicine fluid in the syringe barrel (10) flows over the fluid
passage of the needle mount (20) towards the needle (40) until the
plunger (32) is fully extended into the syringe barrel (10) and
the plunger crown (322) contacts the lower end of the needle mount
(20), thus the medicine fluid retention in the syringe barrel (10)
is minimized.
2. The medicine fluid in the safety syringe of the invention directly
flows from the syringe barrel (40) over the fluid passage in a substantially
direct way towards the needle (40), so that air bubbles are easily
obviated.
3. Due to the simple structure of retractable safety syringe, the
components of the retractable safety syringe are easily molded and
assembled under low production cost and high production efficiency.
4. The structure of the present invention ensures that the tip
end portion (324) is able to be inserted into the fluid passage
of the inner hub (24) until the neck portion (326) is clamped by
the spring clamps (240), so that the needle mount (20) is properly
engaged with the plunger rod (30), and the user can easily withdraw
the plunger rod (30) to retract the needle (40) in the syringe barrel
(10). When the plunger crown (322) moves up to the annular retaining
groove (18), the peripheral edge of the plunger crown (322) is extended
outwardly by its resilient force and limited in the retaining groove
(18), so that the needle (40) and the plunger (32) are retained
within the syringe barrel (10), and the used syringe of the invention
can be safely disposed without fear of it being reused.
5. Because the outer hub (22) of the needle mount is formed with
a configuration feature to facilitate assembly of the needle (40),
the safety of operation of the syringe is ensured.
It is to be understood, however, that even though numerous characteristics
and advantages of the present invention have been set forth in the
foregoing description, together with details of the structure and
function of the invention, the disclosure is illustrative only,
and changes may be made in detail, especially in matters of shape,
size, and arrangement of parts within the principles of the invention
to the full extent indicated by the broad general meaning of the
terms in which the appended claims are expressed. |