Safety syringe abstract
A safety syringe includes: a syringe cylinder having a plurality
of sleeve ribs formed in a sleeve portion of the syringe cylinder,
a needle device having a needle detachably coupled on an shank portion
which is provided with a plurality of shank ribs on the shank portion
to be engaged with the sleeve ribs in the sleeve portion, with the
needle device retractable in and automatically biased in the syringe
cylinder to prevent outward protruding of used needle; whereby upon
external connecting and rotative coupling of the needle on the shank
portion, the shank portion will be locked without being rotatable,
thereby enhancing a smooth coupling of the needle on the shank portion
of the needle device.
Safety syringe claims
I claim:
1. A safety syringe comprising: a syringe means having a syringe
cylinder formed with a sleeve portion on a front portion of said
syringe cylinder; a needle device detachably secured on said syringe
cylinder and including: a hollow needle, a shank portion for externally
connecting the hollow needle thereon and a locking head portion
formed on a rear portion of said shank portion; and a plunger means
slidably held in said syringe cylinder, having a plunger secured
to a plunger rod and recessed with a biasing socket in said plunger
for coupling said locking head portion of said needle device in
said biasing socket when completing an injection, said plunger as
coupled with said needle device operatively retracted into said
syringe cylinder for tilting said needle without re-protruding said
needle forwardly from said sleeve portion; the improvement which
comprises: said sleeve portion having a plurality of sleeve ribs
longitudinally formed on an inside wall in a sleeve hole formed
through said sleeve portion; said shank portion having a plurality
of shank ribs longitudinally formed on an outer surface of said
shank portion for respectively engaging said sleeve ribs in said
sleeve portion, and a shallow disk portion formed on a rear portion
of said shank portion to be engaged with a shallow recess formed
in a rear portion of said sleeve hole of said sleeve portion, whereby
upon securing of said shank portion in said sleeve portion and upon
rotation of said shank portion, said shank ribs on said shank portion
will be engaged and locked by said sleeve ribs in said sleeve portion
for preventing a rotation of said shank portion, thereby allowing
a smooth connection of said hollow needle on said shank portion
on said syringe cylinder; and said plunger means including at least
a ratchet tooth formed on a rear portion of a circular disk which
is formed on a front end portion of said plunger rod adjacent to
said plunger, and said syringe cylinder having an annular extension
annularly formed in a rear portion of said syringe cylinder; whereby
upon a rearward pulling of said plunger rod, said ratchet tooth
will be engaged and locked by said annular extension in said syringe
cylinder for preventing a rearward releasing of said plunger means
from said syringe cylinder once inserted into said syringe cylinder.
2. A safety syringe according to claim 1 wherein said shank portion
further includes a packing ring annularly formed on said shank portion
to be engaged with an inside wall of said sleeve hole in said sleeve
portion, and said packing ring forwardly limited by said sleeve
ribs in said sleeve portion.
3. A safety syringe according to claim 1 wherein said ratchet
tooth is formed as an annular ratchet tooth annularly formed in
a rear portion of said circular disk as formed on a front end portion
of said plunger rod.
Safety syringe description
BACKGROUND OF THE INVENTION
This invention is an improvement of U.S. Pat. No. 5533975 (hereinafter
called "prior art") also invented by the present inventor.
The prior art disclosed a safety syringe for automatically tilting
a used needle when retracted into the syringe to prevent re-protrusion
of the needle outwardly. A cylindrical recess 125 is recessed in
the front portion of the syringe 1 provided with two wedged extensions
126 formed on the recess 125 for retarding two bars 225 diametrically
formed on a cylindrical portion 224 of the shank portion 22 of the
needle assembly, thereby preventing rotation of the shank portion
when rotatably coupling the needle portion 21 and the shank portion
22. However, such a cylindrical recess 125 will be accumulated with
liquid medicine to form a "dead pool" which can not be
completely injected into a patient, causing waste of the medicine.
The present inventor has found the drawbacks of the prior art and
invented the present improved safety syringe.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a safety syringe
including: a syringe cylinder having a plurality of sleeve ribs
formed in a sleeve portion of the syringe cylinder, a needle device
having a needle detachably coupled on an shank portion which is
provided with a plurality of shank ribs on the shank portion to
be engaged with the sleeve ribs in the sleeve portion, with the
needle device retractable in and automatically biased in the syringe
cylinder to prevent outward protruding of used needle; whereby upon
external connecting and rotative coupling of the needle on the shank
portion, the shank portion will be locked without being rotatable,
thereby enhancing a smooth coupling of the needle on the shank portion
of the needle device.
Another object of the present invention is to provide a safety
syringe including an annular extension annularly formed on an inside
wall of the syringe cylinder adjacent to a rear end of the syringe
cylinder and at least a ratchet tooth formed on a front portion
of a plunger slidably held in the syringe cylinder; whereby the
annular extension provides a stopper for preventing a rearward releasing
of the plunger from the cylinder since the ratchet tooth on the
plunger will be locked against the annular extension when accidentally
pulling the plunger rearwardly outwardly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional drawing showing a shank portion of a needle
device separated from a syringe cylinder of the present invention.
FIG. 2 is a sectional drawing of the present invention when assembled
from FIG. 1.
FIG. 3 is a sectional drawing showing the engagement of the needle
device with the plunger when finishing an injection in accordance
with the present invention.
FIG. 4 shows a retracted and tilted needle in a syringe cylinder
of the present invention.
FIG. 5 is an illustration showing the prevention of an outward
releasing of the plunger from the syringe cylinder.
FIG. 6 shows another embodiment of the plunger means having ratchet
tooth formed thereon.
DETAILED DESCRIPTION
As shown in FIGS. 1.about.5 the safety syringe of the present
invention comprises: a syringe means 1; a needle device 2 detachably
secured on the syringe means 1; and a plunger means 3 slidably held
in the syringe means 1.
The syringe means 1 includes: a syringe cylinder 11 having an interior
10 for filling liquid medicine therein, a sleeve portion 12 formed
on a front portion of the cylinder 11 having a sleeve hole 12a formed
through the sleeve portion 12 a shoulder portion 13 formed in between
the sleeve portion 12 and the cylinder 11 a syringe handle 14 formed
on a rear end of the cylinder 11 and an annular extension 15 annularly
formed on an inside wall of the cylinder 11 adjacent to the syringe
handle 14.
The sleeve portion 12 has a plurality of sleeve ribs 12b longitudinally
formed on an inside wall of the sleeve hole 12a, and a shallow recess
12c recessed in a rear portion of the sleeve portion 12 and having
a diameter of the shallow recess 12c slightly larger than the diameter
of the sleeve hole 12a (FIG. 4).
The needle device 2 includes: a hollow needle 21 having a needle
hole 20 formed through the needle 21 and having a coupling sheath
21a secured to a rear portion of the needle 21 and formed with female
threads 21b in the coupling sheath 21a; a shank portion 22 detachably
secured in the sleeve hole 12a of the sleeve portion 12 to be coupled
with the coupling sheath 21a of the needle 21; and a locking head
portion 23 formed on a rear end of the shank portion 22 having a
discharge slot 24 formed in the locking head portion 23 and in the
shank portion 22 to be fluidically communicated with the needle
hole 20 of the hollow needle 21 for passing the liquid medicine
through the relevant holes 24 20 to be injected into a patient's
body.
The shank portion 22 includes: a shallow disk portion 22a formed
on a rear end of the shank portion 22 to be engaged with the shallow
recess 12c when securing the shank portion 22 in the sleeve portion
12 a plurality of shank ribs 22b longitudinally formed on a circumference
of the shank portion to be engaged with the sleeve ribs 12b in the
sleeve portion 12 a packing ring 22c disposed about the shank portion
22 and engaged with the inside wall of the sleeve hole 12a and forwardly
retarded by the rib ends of the sleeve ribs 12b when mounting the
shank portion 12 in the sleeve portion 12 for preventing leakage
during injection of the needle 21 and a stem portion 22d formed
on a front portion of the shank portion 22 having a pair of projections
22e circumferentially formed on the stem portion 22d for engaging
the female threads 21b formed in the coupling sheath 21a of the
needle 21 for externally connecting the coupling sheath 21a of the
needle with the shank portion 22 previously secured in the sleeve
portion 12 of the syringe cylinder 11.
The plunger means 3 includes: a plunger 31 secured on a front end
portion 34 of a plunger rod 35 slidably held in the syringe cylinder
11 a biasing socket 32 recessed in the plunger 31 for engaging
the locking head portion 23 of the needle device 2 through a guiding
port 33 formed in the plunger 31 after finishing the injection,
and at least a ratchet tooth 35b formed on a rear portion of a circular
disk 35a (having arcuate front edge portion on the disk 35a) formed
on a front portion of the plunger rod 35 with the ratchet tooth
35b operatively retarded against the annular extension 15 formed
in the cylinder 11 when pulling the plunger rod 35 rearwardly outwardly
(FIG. 5) for preventing a rearward releasing of the plunger means
3 from the cylinder 11 after finishing the injection.
When assembling the hollow needle 21 of the present invention,
the coupling sheath 21a of the needle 21 is rotated to engage the
female threads 21b therein with the projections 22e on the stem
portion 22d, the shank ribs 22b will be engaged and retarded by
the sleeve ribs 12b in the sleeve portion 12 to prevent from a rotation
of the shank portion 22 thereby allowing a smooth rotation of the
coupling sheath 21a about the shank portion 22 until firmly securing
the sheath 21a (of the needle 21) on the shank portion 22 which
is already secured in the sleeve portion 12 of the syringe means
1.
The cylindrical recess 125 and the extensions 126 as provided in
the front portion of the syringe of the prior art are now eliminated,
indicating that there is no "dead pool" formed in the
front portion of the syringe cylinder of the present invention and
thereby exhausting all liquid medicine in the cylinder after completing
the injection without wasting the liquid medicine and being superior
to the prior art.
After completing the injection, the locking head portion 23 of
the needle device 2 as engaged with the biasing socket 32 in the
plunger will be simultaneously retracted into the cylinder 11 and
will be automatically tilted from the axis X (from FIG. 3 to FIG.
4) for a safe protection of the syringe.
The ratchet tooth (or teeth) 35b as recessed or formed in a rear
portion of the circular disk 35a of the plunger means 3 can be plural
ratchet teeth 35b (the number and shapes of teeth being not limited)
circumferentially formed in a front portion of the plunger rod 35
as shown in FIG. 6 or may be formed as an annular ratchet tooth
35b annularly formed on a front portion of the plunger rod 35 as
shown in FIG. 5.
The arcuate front edge portion of the circular disk 35a on the
front end portion of the plunger rod 35 may be smoothly inserted
into the interior 10 of the syringe cylinder 11 by passing through
the annular extension 15 when assembling the plunger means 3 in
the cylinder 11. However, when rearwardly pulling the plunger rod
35 as shown in FIG. 5 the ratchet tooth (or teeth) 35b will be
retarded or locked on the annular extension 15 to thereby prevent
from an outward rearward releasing of the plunger means 3 from the
cylinder 11 especially when coupled with a tilted needle 21 thereon
(FIGS. 4 & 5).
Accordingly, the present invention really provides a safety syringe
to prevent from a forward protruding of a used needle as retracted
in the syringe cylinder (FIG. 4); and also to prevent from a rearward
releasing of the plunger 31 coupled with the used needle 21 from
the cylinder 11 (FIG. 5). The used needle 21 will be well "trapped"
in the cylinder 11 for absolutely ensuring the safety protection
of a syringe (for preventing from sticking injury of a used needle
to a nurse, a doctor, a hospital cleaner or housekeeper, etc.)
The present invention may be modified without departing from the
spirit and scope of the present invention.
The present invention may be used for hypodermic injection and
may also be modified to be used for intravenous injection. |