Safety syringe abstract
A safety syringe has a hollow barrel, a plunger, a connector, a
plug and a needle hub. The plunger has a protrusion extended from
the plunger and along a longitudinal axis of the plunger. The connector
is mounted around the protrusion of the plunger. Multiple limit
stubs and multiple curved limit channels communicating with a corresponding
notch with an inclined side-wall are respectively formed on the
connector and a connecting chamber in a connecting tube of the needle
hub. When the plunger is being pushed towards the needle hub, the
multiple limit stubs respectively pass through the corresponding
curved limit channel and are contained in the corresponding notch.
The inclined side-wall of the notch will stably connect the limit
stub so the plunger can stably retract the needle hub in the hollow
barrel.
Safety syringe claims
What is claimed is:
1. A safety syringe comprising: a hollow barrel having a proximal
open end; and a distal open end; a plunger slidably mounted inside
the hollow barrel and having a distal end; a proximal end; a neck
formed integrally and extending from the proximal end of the plunger,
and having a distal end, a proximal end and a longitudinal axis;
a first positive limit attached to the distal end of the neck; a
protrusion extended from the first positive limit and along the
longitudinal axis of the neck, and having a distal end and a proximal
end; and a second positive limit attached to the distal end of the
protrusion; a plug mounted around the neck on the plunger; a cylindrical
connector rotatively mounted around the protrusion of the plunger,
and having a side-wall; a longitudinal axis; a through hole formed
along the longitudinal axis of the connector; and a groove formed
in the side-wall and parallel to the longitudinal axis of the connector,
and communicating with the through hole of the connector; a needle
hub mounted in the proximal open end of the hollow barrel and having
a connecting tube having a distal end; a proximal end; and a connecting
chamber formed in the distal end of the connecting tube and having
a proximal open end, a distal closed end and an inner surface, wherein
the connecting chamber has a radius larger than that of the connector;
and a needle attached to the proximal end of the connecting tube
and having a central passage; and an engaging device formed between
the connector and the connecting chamber of the needle hub and connected
the connector and the connecting chamber of the needle hub together
when the connector is inserted in to the connecting chamber, and
comprising multiple limit stubs; multiple curved limit channels
each corresponding to one of the limit stubs and having a first
inclined side wall; and multiple notches each communicating with
one of the curved limit channels and having a second inclined side
wall formed opposite to the first inclined side wall on a corresponding
one of the curved limit channels, and the first inclined side wall
formed near the corresponding notch, wherein each notch is larger
than the corresponding limit stub and each limit stub wedges against
the second inclined side wall of the corresponding notch when the
connector is inserted into the connecting chamber.
2. The safety syringe as claimed in claim 1 wherein the push rod
further comprises a V-shape groove defined radially in the push
rod.
3. The safety syringe as claimed in claim 1 wherein the multiple
limit stubs protrudes from the side-wall of the connector; the multiple
curved limit channels are defined in the inner surface and opened
from the proximal open end of the connecting chamber; and the multiple
notches are formed in the inner surface of the connecting chamber.
4. The safety syringe as claimed in claim 3 wherein the push rod
further comprises a V-shape groove defined radially in the push
rod.
5. The safety syringe as claimed in claim 1 wherein the multiple
curved limit channels are defined in the side-wall of the connector
and open toward the needle hub; the multiple notches are formed
in the side-wall of the connector; and the multiple limit stubs
are protruded from the inner surface of the connecting chamber.
6. The safety syringe as claimed in claim 5 wherein the push rod
further comprises a V-shape groove defined radially in the push
rod.
Safety syringe description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a syringe, and more particularly
to a safety syringe that can stably retract the used needle.
[0003] 2. Description of Related Art
[0004] A conventional syringe has a hollow barrel, a plunger and
a needle hub. Due to possible exposure to contagious diseases, the
needle of the syringe and even the hollow barrel and the plunger,
should not be used again and should be discarded immediately after
use. Also, to keep nurses, doctors or health workers who deal with
discarded syringes from getting injured or infected by used needles,
a safety syringe is needed. In particular, manufacturers have focused
on syringes with retractable needles so that once the syringe has
been used, the contaminated needle is entirely housed within the
barrel whereby the chance of infection through accidental pricking
is eliminated.
[0005] A conventional safety syringe disclosed in Taiwan Pat. No.
356013 and comprises a hollow barrel, a plunger and a needle hub.
The plunger has a connector formed on one end of the plunger to
connect with the needle hub. The connector has a protrusion. The
needle hub comprises a chamber and an annular rib. The chamber has
a distal closed end and a proximal open end. The annular rib extends
radially inward from the proximal open end of the chamber. The protrusion
of the connector can be clipped by the annular rib of the needle
hub to connect the plunger and the needle hub together. When the
plunger is pushed to the needle hub, the connector of the plunger
is pressed by the annular rib of the needle hub and then contained
in the needle hub, whereafter pulling the plunger will retract the
needle hub into the hollow barrel.
[0006] However, the connector of the plunger and the needle hub
often separate from each other after the plunger is pulled back
to retract the needle hub. When the protrusion of the connector
is pulled toward the hollow barrel, since the needle hub is elastically
connected to the annular rib of the needle hub, the elastic connection
often slips to let the protrusion of the connector separate from
the needle hub. If the annular rib of the needle hub is produced
small in order to prevent from the protrusion of the connector separating
from the needle hub, the protrusion of the connector will be difficult
to mount in the chamber of the needle hub when trying to engage
the plunger with the needle hub.
SUMMARY OF THE INVENTION
[0007] The main objective of the present invention is to provide
a safety syringe that can have reliable engagement and separation
between a plunger and a needle hub. To achieve the objective, a
safety syringe in accordance with the present invention comprises
a hollow barrel, a plunger, a connector, a plug and a needle hub.
The plunger is slidably mounted in the hollow barrel, and has a
neck to mount the plug and a protrusion extended from the plunger
and along a longitudinal axis of the neck. The connector is mounted
around the protrusion of the plunger. The needle hub is mounted
in one end of the hollow barrel and comprises a connecting tube
and a needle. Multiple limit stubs and multiple curved limit channels
communicated with a corresponding notch with a second inclined side
wall are respectively formed on the connector and in the connecting
chamber of the needle hub. When the plunger is being pushed toward
the needle hub, the multiple limit stubs respectively pass through
the corresponding curved limit channel and are contained in the
corresponding notch. The second inclined side wall of the notch
will stably connect the limit stub so the plunger can stably retract
the needle hub in the hollow barrel.
[0008] Further benefits and advantages of the present invention
will become apparent after a careful reading of the detailed description
with appropriate reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a perspective view of a safety syringe in accordance
with the present invention;
[0010] FIG. 2 is an exploded perspective view of the safety syringe
in FIG. 1;
[0011] FIG. 3 is a perspective view of the partial safety syringe
in FIG. 1;
[0012] FIG. 4 is a perspective view of the partial safety syringe
in FIG. 1 showing multiple limit stubs on a connector respectively
mounted into a corresponding recess inside a connecting tube;
[0013] FIG. 5 is a perspective view of the safety syringe in FIG.
1 showing the needle hub retracted back into a hollow barrel; and
[0014] FIG. 6 is an exploded perspective view of a second embodiment
of a safety syringe in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] With reference to FIGS. 1 2 and 6 a safety syringe in
accordance with the present invention comprises a hollow barrel
(10), a plunger (20), a plug (30), a connector (4040'), an engaging
device (not numbered) and a needle hub (5050').
[0016] The hollow barrel (10) is cylindrical and has a proximal
open end (not numbered), a distal open end (not numbered), a lip
(not numbered) and an annular flange (not numbered). The lip extends
radially inward from the proximal open end of the hollow barrel
(10) so the proximal open end is smaller than the distal open end.
The annular flange extends radially out from the distal open end
of the hollow barrel (10).
[0017] The plunger (20) has a distal end (not numbered), a proximal
end (not numbered), a V-shaped groove (210), a neck (21), a first
positive limit (22), a protrusion (23) and a second positive limit
(24), and is slidably mounted inside the hollow barrel (10). The
neck (21) is formed integrally and extends from the proximal end
of the plunger (20), and has a distal end (not numbered), a proximal
end (not numbered) and a longitudinal axis (not numbered). The first
positive limit (22) is circular and attached to the distal end of
the neck (21). The protrusion (23) is extended from the first positive
limit (22) and along the longitudinal axis of the neck (21), and
has a distal end (not numbered) and a proximal end (not numbered).
The second positive limit (24) is circular and attached to the distal
end of the protrusion (23). The V-shaped groove (210) is defined
radially in the plunger (20).
[0018] The plug (30) is mounted around the neck (21) on the plunger
(20).
[0019] The connector (4040') is cylindrical and rotatively mounted
around the protrusion (23) of the plunger (20), and has a side-wall
(not numbered), a longitudinal axis (not numbered), a through hole
(4242') and a groove (4343'). The through hole (4242') is formed
along the longitudinal axis of the connector (40). The groove (4343')
is formed in the side-wall and extends parallel to the longitudinal
axis of the connector (4040'), and communicates with the through
hole (4242') of the connector (4040').
[0020] With further reference to FIG. 3 the needle hub (5050')
is mounted in the proximal open end of the hollow barrel (10) and
has a connecting tube (5151') and a needle (52). The connecting
tube (5151') has a distal end (not numbered), a proximal end (not
numbered) and a connecting chamber (512512'). The connecting chamber
(512512') is formed in the distal end of the connecting tube (5151')
and has a proximal open end (not numbered), a distal closed end
(not numbered) and an inner surface (not numbered). The connecting
chamber (512512') has a radius larger than that of the connector
(4040'). The needle (52) is attached to the proximal end of the
connecting tube (5151') and has a central passage (not shown).
[0021] The engaging device is formed between the connector (4040')
and the connecting chamber (512512') of the needle hub (5050').
The engaging device connects the connector (4040') and the connecting
chamber (512512') of the needle hub (5050') together when the
connector (4040') is inserted into the connecting chamber (512512').
In a first embodiment, the engaging device comprises multiple limit
stubs (41), multiple curved limit channels (510) and multiple notches
(511). The multiple limit stubs (41) protrude from the side-wall
of the connector (40). The multiple curved limit channels (510)
are defined in the inner surface and respectively correspond to
a limit stub (41), and each opens from the proximal open end of
the connecting chamber (512). The multiple curved limit channels
(510) are trumpet shaped and each curved limit channel has a first
inclined side wall (514). The multiple notches (511) are formed
in the inner surface and respectively communicate with a corresponding
curved limit channel (510), and have a second inclined side wall
(not numbered). The first inclined side wall (514) and the second
inclined side wall are formed oppositely and the first inclined
side wall (514) is formed near the notch (511). The multiple notches
(511) of the connecting tube (51) can respectively contain a corresponding
limit stub (41) and each notch (511) is larger than the corresponded
limit stub (41).
[0022] With reference to FIG. 6 a second embodiment of the engaging
device comprises multiple curved limit channels (44), multiple notches
(45) and multiple limit stubs (513). The multiple curved limit channels
(44) are defined in the side-wall of the connector (40') and open
toward the needle hub (50). The curved limit channels (44) of the
connector (40') are trumpet shaped and has a first inclined side
wall (46). The multiple notches (45) are formed in the side-wall
of the connector (40) and respectively communicate with a corresponding
curved limit channel (44), and each notch (45) has a second inclined
side wall (not numbered). The first inclined side wall (46) and
the second inclined side wall are formed oppositely and the first
inclined side wall (46) is formed near the notch (45). The multiple
limit stubs (513) protrude from the inner surface of the connecting
chamber (512') and correspond to the respective curved limit channel
(44) of the connector (40'). The multiple limit stubs (513) of the
connecting tube (51') can be respectively contained in the corresponding
notch (45) of the connector (40'). Each limit stub (513) is smaller
than the corresponding curved limit channel (44) of the connector
(40').
[0023] With further reference to FIGS. 3 and 4 the safety syringe
is used and the plunger (20) is pushed toward the proximal open
end of the hollow barrel (10) to engage with and retract the needle
hub (50). The connector (40) will rotate to a suitable location
and let the multiple limit stubs (41) of the connector (40) respectively
move along the corresponding curved limit channel (510) and the
first inclined side wall such that each limit stub (41) is mounted
into the corresponding notch (511). Thus, the plunger (20) and the
needle hub (50) are connected together. Pulling back the plunger
(20) into the hollow barrel (10) will let each limit stub (41) wedge
with the second inclined side wall of the notch (511) and stably
connect the plunger (20) and the needle hub (50). Continuously pulling
the plunger (20) will retract the needle hub (50) into the hollow
barrel (10).
[0024] With further reference to FIG. 5 pulling the plunger (20)
toward the distal open end of the hollow barrel (10) will pull the
needle hub (50) back into the hollow barrel (10). Since the radius
of the connecting chamber (512) in the needle hub (50) is larger
than that of the connector (40), the needle (52) will incline by
gravity and use the limit stub (41) as a fulcrum. The needle hub
(50) cannot be pushed out from proximal open end of the hollow barrel
(10). After the V-shaped groove (210) of the plunger (20) exits
the hollow barrel (10), the V-shaped groove (210) of the plunger
(20) permits the protruding portion of the plunger (20) to be snapped
off whereby the needle hub (50) is retained inside the hollow barrel
(10).
[0025] In the second embodiment of the safety syringe, with reference
to FIG. 6 the connector (40') will rotate to a suitable location
and let the multiple limit stubs (41) of the connecting chamber
(512') in the needle hub (50') respectively move along the corresponding
curved limit channel (44) and be mounted into the corresponding
notch (45). The multiple limit stubs (41) will respectively wedge
to the corresponding second inclined side wall of the notch (45).
Thus, the plunger (20) and the needle hub (50') are connected together
stably.
[0026] The safety syringe in accordance with the present invention
can let the plunger (20) connect with the needle hub (5050') stably.
After the safety syringe has been used to treat a patient, the plunger
(20) can connect with the needle hub (5050') to let the needle
hub (5050') retract back in the hollow barrel (10).
[0027] Although the invention has been explained in relation to
its preferred embodiment, many other possible modifications and
variations can be made without departing from the spirit and scope
of the invention as hereinafter claimed is to be understood. |