Safety syringe abstract
A safety syringe has a barrel, a needle hub movably received in
the barrel and having a hollow cone with a flange formed on an inner
periphery of the hollow cone and a plunger with a hook formed to
correspond to the flange of the needle hub. The plunger has a spacer
formed on the top face of the stop to be adapted to detachably engage
with a bottom face of the hollow cone to keep the hook from engagement
with the flange. The spacer is made of a material of resilience
such that when the spacer is so deformed that the hook engages with
the flange so as to pull the needle hub back into the barrel.
Safety syringe claims
What is claimed is:
1. In a safety syringe having a barrel, a needle hub movably received
in the barrel and having a needle securely attached to a distal
end of the needle hub and a plunger slidably received in the barrel
and having a thumb press formed on a first distal end of the plunger
and a stop formed on a second distal end of the plunger, wherein
the improvements comprise: the needle hub has a hollow cone with
a flange formed on an inner periphery of the hollow cone; the plunger
has a hook adapted to be integrally formed on a top face of the
stop to correspond to the flange of the needle hub so that when
the hook engages with the flange of the needle hub, the needle hub
is able to be pulled back into the barrel by a rearward movement
of the plunger and the needle is damaged by a forward movement of
the plunger after the needle hub is entirely received in the barrel
and a spacer formed on the top face of the stop to be adapted to
detachably engage with a bottom face of the hollow cone to keep
the hook from engagement with the flange, the spacer being made
of a material of resilience such that when the spacer is so deformed
the hook engages with the flange so as to pull the needle hub back
into the barrel
Safety syringe description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a safety device for a safety
syringe, and more particularly to a safety device which is able
to prevent accidental engagement of a hook to a needle hub and to
satisfactorily pull the needle hub back into the barrel when required
so that the syringe is able to be disposed of safely.
[0003] 2. Description of Related Art
[0004] Numerous patents discussing different structures and means
of preventing accidental damage to paramedic personnel by used syringes
have already been introduced to the market. Reviewing the patents,
most of them concern the means of how the needle is retracted into
the barrel. However, in most of the information provided in the
available patents, if the user is not careful when trying to receive
medicine in the barrel, the plunger prematurely securely engages
with the needle hub such that the syringe is no longer useful in
injection.
[0005] To overcome the shortcomings, the present invention tends
to provide an improved safety device for a safety syringe to mitigate
and obviate the aforementioned problems.
SUMMARY OF THE INVENTION
[0006] The primary objective of the present invention is to provide
an improved safety device for a safety syringe so that prior to
giving the injection the user is able to readily pull the needle
hub back into the barrel without worrying that the needle hub is
accidentally retracted into the barrel.
[0007] In order to accomplish the foregoing objective, the syringe
has a barrel, a plunger movably received in the barrel and provided
with a hook integrally formed with a stop which is formed on a distal
end of the plunger and a spacer deformably formed on a top face
of the stop, and a needle hub movably received in the barrel and
having a flange formed on an inner periphery of the needle hub to
correspond to the hook. Engagement between the needle hub and the
hook enables the needle together with the needle hub to be readily
retracted into the barrel so that accidental damage to the paramedic
personnel is prevented. Furthermore, because of the deformability
of the spacer, engagement of the spacer with the needle hub will
not allow the hook to engage with the flange of the needle hub unless
a force is applied to deform the spacer, which triggers engagement
between the hook and the flange of the needle hub so that the user
is able to use the syringe without accidental engagement of the
hook with the flange of the needle hub to disable the syringe.
[0008] 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
[0009] FIG. 1 is an exploded perspective view showing the parts
of the syringe of the present invention;
[0010] FIG. 2 is a cross sectional view showing an assembly among
the barrel, the needle hub and the plunger;
[0011] FIG. 3 is a cross sectional view showing the hook engages
with the flange of the needle hub;
[0012] FIG. 4 is a cross sectional view showing that the needle
hub is retracted back into the barrel by the rearward movement of
the plunger; and
[0013] FIG. 5 is a schematic view showing that the needle of the
needle hub is broken by the forward movement of the plunger.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] With reference to FIG. 1 a safety syringe has a barrel
(1), a needle hub (2) and a plunger (3).
[0015] The barrel (1) is hollow inside to receive therein the needle
hub (2) and the plunger (3).
[0016] The needle hub (2) is detachably received in the barrel
(1) and has a hollow cone (21) and a flange (22) formed on an inner
periphery of the hollow cone (21) of the needle hub (2). A needle
(23) is replaceably mounted on top of the needle hub (2) so that
when necessary, the user is able to replace a damaged needle (23)
before use.
[0017] The plunger (3) has a thumb push (31) formed on a first
distal end of the plunger (3) and a stop (32) formed on a second
distal end of the plunger (3) and having a hook (321) integrally
formed on a top face of the stop (32) to correspond to the flange
(22) of the hollow cone (21). The plunger (3) further has a spacer
(33) integrally formed on the top face of the stop (32). The spacer
(33) is made of a material with resilience such that the spacer
(33) is deformable. Furthermore, the hook (321) extends out of the
spacer (33) from the stop (32).
[0018] With reference to FIG. 2 when the safety syringe of the
present invention is in assembly, the needle hub (2) is first inserted
into the barrel (1) so as to secure relative position of the needle
hub (2) to the barrel (1). Meantime, the plunger (3) is also received
in the barrel (1) to be ready to receive medicine in the barrel
(1). From FIG. 2 it is noted that before the syringe of the present
invention is in use, the spacer (33) is in engagement with a bottom
face of the hollow cone (21) of the needle hub (2) and a free end
of the hook (321) is not received in the hollow cone (21), thereby
the user can safely use the syringe to receive medicine in the barrel
(1) without worrying that the hook (321) might be accidentally in
engagement with the needle hub (2) to disable the syringe.
[0019] Furthermore, the hook (321) is preferably made of a metal.
The hook (321) is bent so that a free end of the hook (321) is resilient
relative a distal end securely formed with the stop (32).
[0020] With reference to FIG. 3 when the medicine inside the barrel
(1) is ejected out of the barrel (1), the user pushes the plunger
(3) all the way into the barrel (1) to force the spacer (33) to
deform such that the hook (321) is received in the hollow cone (21).
Because of the resilience of the hook (321), the hook (321) is able
to engage with the flange (22) of the hollow cone (21). Thereafter
the user is ready to pull the needle hub (2) back into the barrel
(1).
[0021] With reference to FIG. 4 after the needle hub (2) is retracted
in the barrel (1), because the free end of the hook (321) is in
engagement with one point of the flange (22), the needle hub (2)
is inclined relative to the barrel (1). When the needle hub (2)
is inclined to and fully received in the barrel (1), a forward movement
of the plunger (3) together with the needle hub (2), as shown in
FIG. 5 the needle (23) is bent inside the barrel (1) such that
the safety syringe of the present invention is able to be disposed
of safely.
[0022] It is thus noted that the safety device used in the safety
syringe of the present invention includes the spacer (33) formed
on a top face of the stop (32), the hook (321) formed with the stop
(32) and extending out from the spacer (33) and a flange (22) formed
on the inner periphery of the hollow cone (21) of the needle hub
(2).
[0023] With such an arrangement of the safety device of the present
invention, the user is able to safely use the syringe to perform
an injection and readily pull the needle hub (2) together with the
needle (23) back into the barrel (1).
[0024] 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. |