Safety syringe abstract
A safety syringe has a hollow barrel, a needle hub and a plunger.
The hollow barrel has a distal end, a proximal end, a cone-shaped
end formed on the proximal end with an opening. The plunger has
a proximal end and a needle retractor formed on the proximal end.
The needle hub with a needle is detachably mounted inside the proximal
end of the hollow barrel and has an axial fitting to engage the
plunger. When the safety syringe is used, the plunger connects to
the needle hub and is pulled toward the distal end of the hollow
barrel to draw the needle hub with the needle inside the hollow
barrel to keep people from being hurt or infected by an exposed
needle.
Safety syringe claims
What is claimed is:
1. A safety syringe comprising: (a) a hollow barrel being cylindrical
and comprising: a distal end; a proximal end; a flange formed radially
around and extending out from the distal end; a cone-shaped end
integrally formed at the proximal end of the hollow barrel, said
cone-shaped end having an opening defined therethrough; an inner
surface, and an at least one spiral recess formed on the inner surface
of the cone-shaped end; (b) a plunger comprising: a distal end;
a proximal end; a front head integrally formed on the proximal end
of the plunger and having a top surface; (c) a unitary axially protruding
needle retractor lock; said plunger being connected to said seal
member fixedly seated on said plunger, with the seal having a substantially
circular cross-sectional profile and an outer diameter substantially
equal to an inner cross-sectional diameter of said hollow barrel,
telescopingly received and slidingly contiguous with said inner
surface of said hollow barrel; and, (d) a needle assembly comprising:
a needle hub having a needle and being detachably mounted inside
the proximal open end of the hollow barrel, said needle hub comprising:
an outer surface; an at least one spiral key formed on the outside
surface and received inside the spiral recess of the hollow barrel
when the needle hub is mounted inside the cone-shaped end of the
hollow barrel, said needle assembly being rotatably connectable
to said at least one spiral recess at the cone-shaped end of the
hollow barrel; a locking chamber axially positioned and formed within
said needle assembly and having an inner surface; an at least one
latch lug post fixedly formed on the inner surface of the axial
locking chamber and extending radially inward; a fluid passage communicating
with the inner space in the hollow barrel; and an axial passage
defined through the needle hub to receive an end of the needle,
wherein rotating the plunger connectedly engages the needle assembly
and hub with the needle retractor of the plunger, said needle retractor
formed as a closed contour resilient element having at least one
gap recess formed therein and formed axially on and protruding longitudinally
from the top surface of the front head of said plunger, said closed
contour resilient element being insertable into the locking chamber
of hub, wherein upon a rotation of said closed contour resilient
element said lug post member is received into said gap recess to
capture said needle assembly by the needle retractor of said plunger,
whereby said needle assembly may be axially moved into said hollow
barrel.
2. The safety syringe as claimed in claim 1 wherein the needle
retractor of the plunger is an axial protruding lock, with the latch
of the needle hub comprised of lug post members engagable by the
gap recesses upon the rotation of the plunger.
Safety syringe description
BACKGROUND OF THF INVENTION
1. Field of the Invention
The present invention relates to a syringe, and more particularly
to a safety syringe that can safely hold a used needle and prevent
the syringe from being used more than once.
2. Description of Related Art
To keep doctors, nurses or workers who deal with discarded syringes
from being injured or infected by used needles, safety syringes
with retractable needles have been designed such as the syringe
in Taiwan Patent No. 356013. A conventional safety syringe has a
hollow barrel, a plunger and a needle hub with a needle. The needle
hub of the conventional safety syringe has an axial locking chamber,
and the plunger has a proximal end and a protruding head. The protruding
head is formed on the proximal end of the plunger. After injecting
a medicine into a body, the proximal end of the plunger is pushed
toward the needle hub, and the protruding end of the plunger is
mounted inside the axial locking chamber in the needle hub. When
a user pulls the plunger back, the needle hub will move inside the
hollow barrel to protect a user from being hurt.
Because the needle hub is made of plastic and the protruding head
of the plunger is made of a resilient material, the protruding head
can be pressed into the axial locking chamber in the needle hub.
However, when pulling the plunger with the needle hub back inside
the hollow barrel, the needle hub easily separates from the plunger.
To overcome the disadvantage, the axial locking chamber is made
smaller to securely hold the protruding head of the plunger, but
then the protruding head is hard to press into the axial locking
chamber in the needle hub.
To overcome the shortcomings of conventional safety syringes, the
present invention provides a safety syringe to mitigate or obviate
the aforementioned problem.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a
syringe that is safer and more convenient to use and handle than
a conventional safety syringe. The safety syringe in accordance
with the present invention has a hollow barrel, a needle hub and
a plunger and features incorporated into these main elements to
make the syringe safer and more convenient to use and handle than
conventional safety syringes. The hollow barrel has a distal end,
a proximal end and a cone-shaped end with an opening formed on the
proximal end. The plunger has a proximal end and a needle retractor
formed on the proximal end. The needle hub has a needle, is detachably
mounted inside the proximal end of the hollow barrel and has an
axial fitting to connect to the needle retractor on the plunger.
When the safety syringe is used, the needle retractor on the plunger
connects to the axial fitting on the needle hub, and the plunger
pulls the needle hub with the needle inside the hollow barrel when
the plunger is pulled toward the distal end of the hollow barrel.
With the needle completely and securely inside the hollow barrel,
people cannot be hurt or infected by an exposed needle.
Other objectives, 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 a perspective view of a safety syringe in accordance
with the present invention;
FIG. 2 is an enlarged perspective view of the proximal end of the
safety syringe in FIG. 1;
FIG. 3 is an exploded perspective view of the safety syringe in
FIG. 2;
FIG. 4 is an enlarged side plan view in partial section of the
needle hub mounted in the safety syringe in FIG. 1;
FIG. 5 is an enlarged operational perspective view of the safety
syringe in FIG. 2 with the needle retractor on the plunger connected
to the axial fitting on the needle hub;
FIG. 6 is an end view in partial section of the safety syringe
in FIG. 4 with the needle retractor on the plunger connected to
the axial fitting on the needle hub; and
FIG. 7 is a perspective view of the safety syringe in FIG. 1 with
the needle being pulled into the hollow barrel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIGS. 1 to 3 a safety syringe in accordance
with the present invention has a hollow barrel (10), a plunger (20),
a seal (30) and a needle hub (40) with a needle (41).
The hollow barrel (10) is cylindrical and has a distal end (not
numbered), a proximal end (not numbered), a flange (11), a cone-shaped
end (12) and two spiral recesses (14). The flange (11) is defined
radially around and extends out from the distal end of the hollow
barrel (10). The cone-shaped end (12) has an opening (13) and an
inner surface (not numbered) and is formed at the proximal end of
the hollow barrel (10). The spiral recesses (14) are defined on
the inner surface of the cone-shaped end (12).
The seal (30) is made of resilient material, has an axial through
hole (not numbered) and is mounted slidably inside the hollow barrel
(10).
The plunger (20) has a proximal end (not numbered), a front head
(21) and a needle retractor (not numbered) such as an axial protruding
lock (22). The front head (21) is integrally formed on the proximal
end of the plunger (20) and has a top surface (not numbered). The
axial protruding lock (22) is formed on the top surface of the front
head (21). The axial protruding lock (22) has multiple resilient
pieces (221) and gaps (222) defined respectively between adjacent
resilient pieces (221). The seal (30) is mounted around the front
head (21), and the axial protruding lock (22) extends out of the
through hole in the seal (30).
The needle hub (40) with the needle (41) is mounted detachably
inside the cone-shaped end (12) of the hollow barrel (10) so the
needle (41) extends out of the opening (13). The needle hub (40)
has an outside surface (not numbered), an axial passage (not numbered),
an axial locking chamber (43), at least two spiral keys (42) and
a latch (not numbered) such as multiple posts (44). The axial passage
is defined through the needle hub (40), and one end of the needle
(41) is inserted into the axial passage of the needle hub (40).
The needle (41) has a fluid passage (not numbered) defined axially
through the needle (41). The axial locking chamber (43) has an inside
surface (not numbered) and is defined inside the needle hub (40),
and the axial passage communicates with the axial locking chamber
(43) and the inner space in the hollow barrel (10). The spiral keys
(42) are formed on the outside surface of needle hub (40) and engage
the spiral recesses (14) in the cone-shaped end of the hollow barrel
(10). The posts (44) are formed on the inside surface of the axial
locking chamber (43) of the needle hub (40) and holding the axial
protruding lock (22). When the plunger (20) is pressed completely
into the hollow barrel (10), the axial protruding lock (22) is pressed
into the locking chamber (43) in the needle hub (40), and the posts
(44) slide respectively into a corresponding gap (222) between adjacent
resilient pieces (221) of the axial protruding lock (22).
With reference to FIGS. 4 to 6 the safety syringe can be used
to draw blood from a body by aligning the resilient pieces (221)
of the axial protruding lock (22) with the posts (44) in the locking
chamber (43) and pushing the plunger (20) toward the proximal end
of the hollow barrel (10). The axial protruding lock (22) is pushed
into the axial locking chamber (43) of the needle hub (40), and
the resilient pieces (221) are pressed respectively inward by the
corresponding posts (44) so the plunger (20) can be pulled away
from the proximal end of the hollow barrel (10) again.
With reference to FIG. 7 after the needle (21) is inserted into
a patient to inject medicine, the plunger (20) is rotated so the
gaps (222) between adjacent resilient pieces (221) engage the posts
(44) so the plunger (20) securely attaches to the needle hub (40).
Rotating the plunger (20) with the needle hub (40), the spiral keys
(42) of the needle hub (40) will leave away from the spinal recess
(14) of the hollow barrel (10). Then the plunger (20) can be pulled
away from the proximal end of the hollow barrel (10), the needle
hub (40) and the needle (41) are pulled inside the hollow barrel
(10) so the needle (41) cannot injure anyone.
The safety syringe in accordance with the present invention has
the following advantages:
1. The plunger (20) is securely connected to the needle hub (40)
by the needle retractor engaging the axial fitting. The gaps (222)
in the axial protruding lock (22) respectively engage the posts
(44) to prevent the plunger (20) from pulling away from the needle
hub (40) when the needle (41) is pulled into the hollow barrel (10).
2. Rotating the plunger (20) to engage the needle hub (40) is easier
than techniques used to connect the conventional ones, and the axial
protruding lock (22) can be used with various sizes of the axial
locking chambers (43).
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. |