Safety syringe abstract
A safety syringe comprises a barrel having an aperture in a nose,
a hollow plunger in the nose, the plunger having a hole, a sealing
ring, a rear inverted conic detent, and a hypodermic needle, a fastener
inserted through the aperture in the hole for fastening the barrel
and the plunger together, and a sliding handle having a breakable
neck, an internal clip-like latch having a central groove, and a
plug fastened around the latch, the plug having a front tunnel.
Whereby piercing the tapered end of the detent through the tunnel
into the groove for fastening the plunger and the handle together
at the end of fluid dispensing, removing the fastener from the aperture
and the hole for disengaging the barrel from the plunger, and retracting
the handle into the barrel will allow the neck to be broken or the
needle to be bent prior to bending the neck.
Safety syringe claims
What is claimed is:
1. A disposable, retractable syringe comprising: a hollow syringe
barrel including a forward nose and a transverse aperture in the
nose; a hollow plunger in the nose, the plunger including a transverse
hole aligned with the aperture, an intermediate sealing ring on
its outer surface, an inverted conic detent in its rear end, and
a hypodermic needle in a forward end of the plunger; a fastener
inserted through the aperture in the hole for fastening the barrel
and the plunger together; and a handle slidable in the barrel, the
handle including an internal clip-like latch in its forward end,
the latch having a central groove, and an elastic plastic, hollow
plug fastened around the latch, the plug having a front tunnel aligned
with the groove, whereby piercing the tapered end of the detent
through the tunnel into the groove for fastening the plunger and
the handle together at the end of fluid dispensing, removing the
fastener from the aperture and the hole for disengaging the barrel
from the plunger, and retracting the handle together with the needle
and the plunger until the needle is completely retracted into the
barrel.
2. The syringe of claim 1 wherein the fastener is a pin having
a head larger than both the aperture and the hole.
3. The syringe of claim 1 wherein the fastener is a pin having
a threaded shank.
4. The syringe of claim 1 wherein the handle further comprises
a breakable neck on its forward end, whereby when the needle is
completely retracted into the barrel, the breakable neck will allow
to be broken.
5. The syringe of claim 1 further comprising a sheath having internal
threads and the nose having external threads therearound whereby
completely retracting the needle into the barrel will allow the
nose to be enclosed by the sheath by threadedly securing the internal
threads to the external threads on the nose, wherein the needle
is to be pushed to urge by the handle against the bottom of the
sheath for bending the needle.
6. The syringe of claim 5 wherein the handle further comprising
a breakable neck on its forward end, whereby when the needle is
completely retracted into the barrel, the breakable neck will allow
to be broken.
Safety syringe description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to hypodermic injection devices
and more particularly to a disposable syringe with improved safety
and other advantageous characteristics.
[0003] 2. Description of Related Art
[0004] A conventional so-called safety syringe is shown in FIGS.
11 12 and 13. The syringe comprises a hollow syringe barrel 60
a hollow plunger 70 disposed in a forward nose of the barrel 60
the plunger 70 including a sealing ring 71 on its surface, an inverted
conic detent 72 in its rear end, and a hypodermic needle 73 in the
forward end of the plunger 70 and a handle 80 slidable in the barrel
60 the handle 80 including a breakable neck 81 near its forward
end, an internal clip-like latch 82 in its forward end, the latch
82 having a central groove 820 and a plastic, hollow plug 83 fastened
around the latch 82 the plug 83 having a front tunnel 830 aligned
with the groove 820.
[0005] Operations of the prior safety syringe are detailed below.
Pull the handle 80 rearward to its maximum for drawing fluid into
the barrel 60 (FIG. 11). Next, push the handle 80 forward for discharging
fluid through the plunger 70 and the needle 73. The tapered end
of the detent 72 pierces through the tunnel 830 into the groove
820 for fastening together at the end of fluid dispensing (FIG.
12). A medical worker then can retract the handle 80 together with
the needle 73 and the plunger 70 until the needle 73 is completely
retracted into the barrel 60 (FIG. 13). Finally, break the breakable
neck 81 prior to throwing the syringe away. This can prevent the
needle 73 from accidentally pricking a person after use.
[0006] But this is unsatisfactory for the purpose for which the
invention is concerned for the following reasons: A single sealing
ring 71 is insufficient to completely prevent fluid within the barrel
60 from leaking into the plunger 70. Also, it is possible that both
the needle 73 and the plunger 70 retract into the barrel 60 when
injecting medicine into a hard tissue of the skin through the needle
73 (i.e., high resistance condition). Alternatively, a strong push
of the handle 80 may disengage the needle 73 from the barrel 60
due to pressure buildup inside the barrel 60 and the plunger 70
while dispensing fluid by a medical worker. An addition of additional
one or more sealing rings 71 may solve the above problems. However,
a new problem is arisen. The problem is that the locking force of
the detent 72 inside the groove 820 is insufficient to overcome
the sealing force of the multiple sealing rings 71. As an end, both
the plunger 70 and the needle 73 cannot retract into the barrel
60 after use. Thus, the need for improvement still exists.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a disposable,
retractable safety syringe comprising a hollow syringe barrel including
a forward nose and a transverse aperture in the nose; a hollow plunger
in the nose, the plunger including a hole aligned with the aperture,
an intermediate sealing ring on its surface, an inverted conic detent
in its rear end, and a hypodermic needle in a forward end of the
plunger; a fastener inserted through the aperture in the hole for
fastening the barrel and the plunger together; and a handle slidable
in the barrel, the handle including a breakable neck near its forward
end, an internal clip-like latch in its forward end, the latch having
a central groove, and a plastic, hollow plug fastened around the
latch, the plug having a front tunnel aligned with the groove, whereby
piercing the tapered end of the detent through the tunnel into the
groove for fastening the plunger and the handle together at the
end of fluid dispensing, removing the fastener from the aperture
and the hole for disengaging the barrel from the plunger, and retracting
the handle together with the needle and the plunger until the needle
is completely retracted into the barrel will allow the breakable
neck to be broken. By utilizing this disposable safety syringe,
the above problems of the prior art can be overcome.
[0008] In one aspect of the present invention, the syringe further
comprises a sheath having internal threads and external threads
around the nose whereby completely retracting the needle into the
barrel will allow the nose to be enclosed by the sheath by threadedly
securing the internal threads to the external threads, the handle
to be pushed to urge the needle against the bottom of the sheath
for bending the needle, and the breakable neck to be broken.
[0009] The above and other objects, features and advantages of
the present invention will become apparent from the following detailed
description taken with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a first preferred embodiment
of disposable safety syringe according to the invention;
[0011] FIG. 2 is an exploded view of the syringe shown in FIG.
1;
[0012] FIGS. 3 4 and 5 are cross-sectional views of the syringe
for illustrating positions thereof prior to dispensing, after dispensing,
and after retracting the needle into the barrel respectively;
[0013] FIG. 6 is a perspective view of a second preferred embodiment
of disposable safety syringe according to the invention, where the
sheath is separated for illustration purpose;
[0014] FIGS. 7 and 8 are cross-sectional views of the syringe shown
in FIG. 6 for illustrating positions thereof after dispensing and
after retracting the needle into the barrel respectively;
[0015] FIGS. 9 and 10 are cross-sectional views of the syringe
shown in FIG. 6 for illustrating positions thereof after the sheath
has been secured to a forward nose of the syringe after fluid dispensing
with the needle being bent and after retracting the bent needle
into the barrel and breaking the handle respectively; and
[0016] FIGS. 11 12 and 13 are cross-sectional views of a prior
safety syringe for illustrating positions thereof prior to dispensing,
after dispensing, and after retracting the needle into the barrel
respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Referring to FIGS. 1 to 5 a disposable safety syringe constructed
in accordance with a first preferred embodiment of the invention
is shown. The syringe comprises a hollow syringe barrel 20 including
a transverse aperture 21 in a forward nose, a hollow plunger 30
disposed in the nose of the barrel 20 the plunger 30 including
a hole 31 aligned with the aperture 21 an intermediate sealing
ring 32 on its outer surface for completely preventing fluid within
the barrel 20 from leaking into the plunger 30 an inverted conic
detent 33 in its rear end, and a hypodermic needle 34 in the forward
end of the plunger 30 a pin 10 having an enlarged head in this
embodiment, i.e., the head being larger than both the aperture 21
and the hole 31 (or a threaded shank in any of other embodiments)
being adapted to insert through the aperture 21 in the hole 31 for
fastening the barrel 20 and the plunger 30 together, and a handle
40 slidable in the barrel 20 the handle 40 including a breakable
neck 41 near its forward end, an internal clip-like latch 42 in
its forward end, the latch 42 having a central groove 420 and an
elastic plastic, hollow plug 44 fastened around the latch 42 the
plug 44 having a front tunnel 440 aligned with the groove 420.
[0018] Operations of the safety syringe will be described in detail
below. Pull the handle 40 rearward to its maximum for drawing fluid
into the barrel 20 (FIG. 3). Next, push the handle 40 forward for
discharging fluid through the plunger 30 and the needle 34. The
tapered end of the detent 33 pierces through the tunnel 440 into
the groove 420 for fastening together at the end of fluid dispensing
(FIG. 4). A medical worker then can remove the pin 10 from the aperture
21 and the hole 31 for disengaging the barrel 20 from the plunger
30 prior to retracting the handle 40 together with the needle 34
and the plunger 30 until the needle 34 is completely retracted into
the barrel 20 (FIG. 5). Finally, break the breakable neck 41 prior
to throwing the syringe away. This can prevent the needle 34 from
accidentally pricking a person after use.
[0019] Referring to FIGS. 6 to 10 a disposable safety syringe
constructed in accordance with a second preferred embodiment of
the invention is shown. The second preferred embodiment substantially
has same structure as the first preferred embodiment. The differences
between the first and the second preferred embodiments, i.e., the
characteristics of the second preferred embodiment are detailed
below. A sheath 50 having internal threads 51 is provided. Correspondingly,
external threads 200 are formed around the nose of the barrel 20
(see FIGS. 6 and 7). After the needle 34 has completely retracted
into the barrel 20 a medical worker can enclose the nose of the
barrel 20 by the sheath 50 by threadedly securing the internal threads
51 to the external threads 200. Next, the medical worker can push
the handle 40 forward to urge the needle 34 against the bottom of
the sheath 50 in order to bend the needle 34 to a maximum, i.e.,
the needle 34 is damaged (see FIG. 9). Finally, break the breakable
neck 41 prior to throwing the syringe away (see FIG. 10). This can
prevent the needle 34 from accidentally pricking a person after
use.
[0020] While the invention herein disclosed has been described
by means of specific embodiments, numerous modifications and variations
could be made thereto by those skilled in the art without departing
from the scope and spirit of the invention set forth in the claims.
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