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 distal 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
to 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 5 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
[0001] 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
[0002] 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.
[0003] 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
[0004] The present invention has been accomplished to provide a
safety syringe, which eliminate the aforesaid drawback.
[0005] 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.
[0006] It is another object of the present invention to provide
a safety syringe, which is practical in use.
[0007] 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
[0008] FIG. 1 is a side sectional view of the safety syringe according
to a prefer embodiment of the present invention;
[0009] FIG. 2 is an exploded view of the safety syringe shown in
FIG. 1;
[0010] FIG. 3 is a perspective view of the stopper according to
the prefer embodiment of the present invention;
[0011] FIG. 4 is a side sectional view of the prefer embodiment
of the present invention, showing the stopper engaged into the needle
holder;
[0012] FIG. 5 is a side sectional view of the prefer embodiment
of the present invention, showing the needle holder and the needle
dragged backwards;
[0013] 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;
[0014] 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;
[0015] FIG. 8 is a side sectional view of the prefer embodiment
of the present invention, showing the plunger is pulled out;
[0016] FIG. 9 is an elevational view of an alternate form of the
stopper according to the present invention;
[0017] FIG. 10 is a plain view of another alternate form of the
stopper for the safety syringe according to the present invention;
[0018] FIG. 11 a and FIG. 11b is a plain view of two alternate
forms of the projection of the barrel according to the present invention;
[0019] 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
[0020] Referring to FIGS. 1-3 a safety syringe is shown, which
is to mount a needle 60 comprises:
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] FIG. 9 shows an alternate form of the plunger connector
35A of the stopper, has a cylindrical shape.
[0031] 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.
[0032] FIG. 11a shows another alternate form of the sliding face
16A of the projection of the barrel curved outwards.
[0033] FIG. 11b shows still another alternate form of the sliding
face 16B of the projection of the barrel curved inwards.
[0034] FIG. 12 shows the projection 15A formed integral with the
peripheral wall of the receiving hole 12 of the barrel 10.
[0035] As indicated above, the safety syringe of the present invention
achieves the following advantages:
[0036] 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.
[0037] 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. |