Safety syringe abstract
A safety syringe comprises a barrel having a projection in a rear
end thereof, a needle holder for mount of a needle, the needle holder
having a dragged portion, a stopper movable in the barrel, the stopper
having a drag portion adapted for engaging into the dragged portion
of the needle holder and a plunger connector, a plunger for moving
the stopper in the barrel having a stopper connector engaged with
the plunger connector of the stopper. When pulled backwards to the
end after injection, the plunger connector of the stopper is forced
onto the projection of the barrel and disengaged from the plunger,
enabling the plunger to be removed from said barrel.
Safety syringe claims
What the invention claimed is:
1. A safety syringe, which is to mount a needle, comprising: a
barrel having a tubular body defining a receiving hole, a projection
disposed in one end of said tubular body, and an insertion hole
axially extended through said projection; a needle holder mounted
in the receiving hole of said barrel and for holding the needle
outside said tubular body of said barrel, said needle holder having
a dragged portion; a stopper mounted in said receiving hole of said
barrel for axial movement between two ends of said barrel, said
stopper having a drag portion adapted for engaging into the dragged
portion of said needle holder for enabling said needle holder to
be moved backwards with said stopper in said barrel, and a plunger
connector; and a plunger inserted into the insertion hole of said
barrel, said plunger having a stopper connector engaged into the
plunger connector of said stopper for enabling said stopper to be
moved with said plunger; wherein when pulled said plunger backwards
to carry said stopper, said needle holder and said needle backwards
on end of said barrel, said plunger connector of said stopper is
forced by the projection of said barrel to expand, thereby causing
said stopper to be disengaged from said plunger for enabling said
plunger to be removed from said barrel.
2. The safety syringe as defined in claim 1 wherein said plunger
connector of said stopper have two hook plates symmetrically disposed
at two sides.
3. The safety syringe as defined in claim 1 wherein said plunger
connector of said stopper has a cylindrical shape.
4. The safety syringe as defined in claim 1 wherein said projection
of said barrel has a conical shape.
5. The safety syringe as defined in claim 4 wherein said projection
of said barrel has a sliding face formed in the periphery thereof.
6. The safety syringe as defined in claim 1 wherein said sliding
face of the projection of the barrel is a curved surface.
7. The safety syringe as defined in claim 1 wherein said plunger
connector of said stopper has a sliding face open outwards and adapted
for guiding said plunger connector onto the projection of said barrel.
8. The safety syringe as defined in claim 7 wherein the sliding
face of said plunger connector of said stopper is slopes linearly.
9. The safety syringe as defined in claim 7 wherein the sliding
face of said plunger connector of said stopper is smoothly arched.
Safety syringe description
FIELD OF THE INVENTION
The present invention relates to hypodermic syringes, and more
particularly to a safety syringe, which enables the plunger to be
easily separated from the stopper after injection.
BACKGROUND OF THE INVENTION
In a safety syringe, the plunger has a front end terminating in
a stopper, which has an arrowhead-like front tip adapted for hooking
in the needle holder, for enabling the needle holder and the needle
to be pulled backwards with the plunger and received inside the
barrel after injection.
However, it is difficult to separate the plunger from the barrel
after the needle holder and the needle have been received inside
the barrel. When separating the plunger from the barrel after injection,
the user has to break the plunger.
SUMMARY OF THE INVENTION
The present invention has been accomplished to provide a safety
syringe, which eliminate the aforesaid drawback.
It is one object of the present invention to provide a safety syringe,
which enables the plunger to be conveniently separated from the
barrel after the service of the safety syringe.
It is another object of the present invention to provide a safety
syringe, which is practical in use.
To achieve these objects of the present invention, the safety syringe
comprises a barrel having a projection in a rear end thereof, a
needle holder for holding a needle in a front end of the barrel,
the needle holder having a dragged portion, a stopper movable in
the barrel, the stopper having a drag portion adapted for engaging
into the dragged portion of the needle holder and a plunger connector,
and a plunger for moving the stopper in the barrel having a stopper
connector engaged into the plunger connector of the stopper. When
pulled backwards to the end after injection, the plunger connector
of the stopper is forced onto the projection of the barrel and disengaged
from the plunger, enabling the plunger to be removed from barrel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side sectional view of the safety syringe according
to a prefer embodiment of the present invention;
FIG. 2 is an exploded view of the safety syringe shown in FIG.
1;
FIG. 3 is a perspective view of the stopper according to the prefer
embodiment of the present invention;
FIG. 4 is a side sectional view of the prefer embodiment of the
present invention, showing the stopper engaged into the needle holder;
FIG. 5 is a side sectional view of the prefer embodiment of the
present invention, showing the needle holder and the needle dragged
backwards;
FIG. 6 is a side sectional view of the prefer embodiment of the
present invention, showing the stopper moved to the projection of
the barrel;
FIG. 7 is a schematic view of the prefer embodiment of the present
invention, showing the plunger connector of the stopper forced onto
the projection of the barrel and expanded;
FIG. 8 is a side sectional view of the prefer embodiment of the
present invention, showing the plunger is pulled out;
FIG. 9 is an elevational view of an alternate form of the stopper
according to the present invention;
FIG. 10 is a plain view of another alternate form of the stopper
for the safety syringe according to the present invention;
FIG. 11a and FIG. 11b is a plain view of two alternate forms of
the projection of the barrel according to the present invention;
FIG. 12 is a plain view of an another alternate form of the projection
of the barrel according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1-3 a safety syringe is shown, which is to
mount a needle 60 comprises:
A barrel 10 have a tubular body 11 a receiving hole 12 defined
in the tubular body 11 a hold portion 13 provided at one end, namely,
the rear end of the tubular body 11 a base flange 14 extended around
at the rear end of the tubular body 11 a projection 15 of conical
shape axially forwardly extended from the base flange 14 and suspended
inside the tubular body 11 a sliding face 16 slopingly formed in
the periphery of the projection 15 an insertion hole 17 axially
extended through the center of the projection 15 a position ring
18 extended around in the inside wall of the receiving hole 12 near
the other end, namely the front end, and a front cap 19 capped on
the front end of the tubular body 11.
A needle holder 20 having a holder body 21 is mounted in the receiving
hole 12 of the barrel 10 a stop portion 22 stopped against the
tubular body 11 a seal ring 23 mounted around the periphery to
seal the receiving hole 12 of the barrel 10 a dragged portion 24
in the rear end, and a needle receiving portion 25 at the front
end.
A stopper 30 have a stopper body 31 a seal ring 32 extended around
the periphery of the stopper body 31 and disposed in close contact
with the peripheral wall of the receiving hole 12 of the barrel
10 a drag portion 33 for engaging with the dragged portion 24 of
the needle holder 20 and a plunger connector 35 backwards extended
from the rear side of the stopper body 31. Two hook plates 36 symmetrically
disposed at two sides of the plunger connector 35. Each hook plate
36 has a hook 37 and formed a tapered sliding face 38 at the front
side thereon.
A plunger 40 is a rod member having a shank 41 insertable into
the insertion hole 17 and the receiving hole 12 of the barrel 10
a push-pull portion 45 disposed at one end, namely, the rear end
of the shank 41 and a stopper connector 43 forwardly extended from
the other end, namely, the front end of the shank 41.
When assembled, as shown in FIG. 1 the stopper connector 43 of
the plunger 40 is engaged into the plunger connector 35 of the stopper
30.
During injection, the stopper 30 is moved with the plunger 40 toward
the front end of the barrel 10 to force medicine out of the needle
holder 20 and the needle 60. As show in FIG. 4 after injection,
the drag portion 33 of the stopper 30 is forced into engagement
with the dragged portion 24 of the needle holder 20.
Referring to FIG. 5 when pulling the plunger 40 backwards after
injection, the needle holder 20 and the needle 60 are moved with
the stopper 30 and the plunger 40 backwards into the inside of the
receiving hole 12 of the barrel 10.
Referring to FIGS. 6 and 7 when pulled the plunger 40 backwards
to the end, the tapered sliding faces 38 of the hook plates 36 of
the plunger connector 35 are forced radially outwards by the sloping
sliding face 16 to expand the hook plates 36 thereby causing the
plunger connector 35 to be disengaged from the stopper connector
43 of the plunger 40.
As show in FIG. 8 At this time, the user can easily remove the
plunger 40 from the barrel 10 remaining the stopper 30 the needle
holder 20 and the needle 60 inside the barrel 10.
FIG. 9 shows an alternate form of the plunger connector 35A of
the stopper, has a cylindrical shape.
FIG. 10 shows another alternate form of the sliding face 38A of
the stopper. According to this alternate form, the sliding face
38A of each hook plate of the stopper is smoothly arched.
FIG. 11a shows another alternate form of the sliding face 16A of
the projection of the barrel curved outwards.
FIG. 11b shows still another alternate form of the sliding face
16B of the projection of the barrel curved inwards.
FIG. 12 shows the projection 15A formed integral with the peripheral
wall of the receiving hole 12 of the barrel 10.
As indicated above, the safety syringe of the present invention
achieves the following advantages:
1. When pulled the needle holder and the needle backwards to the
inside of the barrel, the plunger can easily be separated from the
stopper and removed from the barrel.
2. The structure of the safety syringe is simple, and no any additional
means is needed to separate the plunger from the stopper after the
needle holder and the needle have been pulled backwards to the inside
of the barrel. |