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; and 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, 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.
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 shank portion
further includes 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.
4. A safety syringe according to claim 1 wherein said plunger
means includes 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.
5. A safety syringe according to claim 4 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
[0001] This invention is an improvement of U.S. Pat. No. 5533975
(hereinafter called "prior art") also invented by the
present inventor.
[0002] 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.
[0003] The present inventor has found the drawbacks of the prior
art and invented the present improved safety syringe.
SUMMARY OF THE INVENTION
[0004] 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.
[0005] 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
[0006] FIG. 1 is a sectional drawing showing a shank portion of
a needle device separated from a syringe cylinder of the present
invention.
[0007] FIG. 2 is a sectional drawing of the present invention when
assembled from FIG. 1.
[0008] 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.
[0009] FIG. 4 shows a retracted and tilted needle in a syringe
cylinder of the present invention.
[0010] FIG. 5 is an illustration showing the prevention of an outward
releasing of the plunger from the syringe cylinder.
[0011] FIG. 6 shows another embodiment of the plunger means having
ratchet tooth formed thereon.
DETAILED DESCRIPTION
[0012] 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.
[0013] 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.
[0014] 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).
[0015] 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.
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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).
[0023] 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.)
[0024] The present invention may be modified without departing
from the spirit and scope of the present invention.
[0025] The present invention may be used for hypodermic injection
and may also be modified to be used for intravenous injection.
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