Safety syringe abstract
A safety syringe for intravenous injection includes: a syringe
cylinder having a plurality of sleeve ribs formed in a sleeve portion
eccentrically formed on 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. The syringe cylinder is also formed with an annular
extension for limiting a rearward releasing of the plunger once
inserted in the cylinder.
Safety syringe claims
I claim:
1. A safety syringe for intravenous injection comprising:
a syringe means including a syringe cylinder having a sleeve portion
eccentrically formed on a front portion of said syringe cylinder;
a needle device detachably secured on said sleeve portion of 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 a biasing socket eccentrically
recessed 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, 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 further rotation of said shank portion, thereby allowing
a smooth connection of said hollow needle on said shank portion
on said syringe cylinder; and
said syringe cylinder having at least a guiding means circumferentially
formed on an inside wall of said syringe cylinder for slidably longitudinally
guiding said plunger rod in said syringe cylinder to correspondingly
align said biasing socket in said plunger with said locking head
portion of said needle device for reliably coupling said plunger
with said needle device upon completion of an injection.
2. A safety syringe for intravenous injection according to claim
1 wherein said guiding means includes at least a pair of protrusions
formed in said cylinder for slidably guiding and engaging a blade
member longitudinally lengthwise formed on said plunger rod.
3. A safety syringe for intravenous injection 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.
4. A safety syringe for intravenous injection 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.
5. A safety syringe for intravenous injection 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.
6. A safety syringe for intravenous injection according to claim
5 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 a modification of U.S. patent application entitled
"Improved Safety Syringe" (hereinafter called as "prior
application") filed on: Sep. 6 2001 by the same inventor of
this application.
The prior application disclosed a safety syringe having a shank
portion of the needle device locked on the syringe cylinder without
being rotatable for enhancing a smooth coupling of the needle on
the shank portion when assembling the needle device on the syringe
cylinder.
However, the prior application is designed for hypodermic injection
purpose, not suitable for intravenous injection.
The present inventor has found the drawbacks of the prior application
and invented the present safety syringe for intravenous injection.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a safety syringe
for intravenous injection including: a syringe cylinder having a
plurality of sleeve ribs formed in a sleeve portion eccentrically
formed on 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 for intravenous injection 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.
Still another object of the present invention is to provide a safety
syringe for intravenous injection having at least a pair of beads
or protrusions formed on an inside wall of the syringe cylinder
to longitudinally guide the plunger rod, without being rotatable,
for ensuring the coupling of the plunger socket with the needle
locking head when coupling the plunger with the needle device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 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. 2 shows a retracted and tilted needle as bent in a syringe
cylinder of the present invention.
FIG. 3 is a cross sectional drawing when viewed from 3--3 direction
of FIG. 1.
FIG. 4 shows the plunger means having ratchet tooth formed thereon.
DETAILED DESCRIPTION
As shown in FIGS. 1.about.4 the safety syringe for intravenous
injection of the present invention comprises: a syringe means 1;
a needle device 2 detachably and eccentrically secured on the syringe
means 1; and a plunger means 3 including a plunger 31 and a plunger
rod 35 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 eccentrically
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.
There are four (or plural) pairs of beads or tiny protrusions 16
respectively circumferentially formed on an inside wall in the syringe
cylinder 11 adjacent the annular extension 15 with each pair of
beads 16 slidably engaging a blade member 351 of the plunger rod
35 as shown in FIG. 3.
Such pairs of beads or protrusions 16 will be defined as "guiding
means" in this application for longitudinally slidably guiding
the plunger rod 35 in the syringe cylinder 11. Each bead or protrusion
16 should have a small size for an easy assembly of the plunger
in the cylinder 11.
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. 2).
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 22 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 needle 21 defines a needle axis 200 at its longitudinal center
to be parallel to the longitudinal axis X of the syringe cylinder
11 (FIG. 1).
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 eccentrically recessed in the plunger 31
for correspondingly 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. 2) 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.
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 FIG. 1 to FIG. 2) 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. 4 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. 2.
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 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 (FIG. 2).
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; and also to prevent from a rearward releasing
of the plunger 31 coupled with the used needle 21 from the cylinder
11. 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 plunger rod 35 is formed with four blade members 351 lengthwise
along the rod 35 to have a cross section of cross shape (FIG. 3),
each blade member 351 slidably longitudinally guided and engaged
by each pair of beads or protrusions 16 circumferentially formed
on the inside wall of the syringe cylinder 11.
The plunger rod 35 will not be rotated about the axis X when longitudinally
guided by the beads 16 to ensure a precise coupling of the socket
32 of the plunger 31 with the locking head portion 23 of the needle
device 2 after finishing the injection (FIG. 1). Otherwise, when
the plunger rod 35 is rotated during the injection, the socket 32
may not be aligned with the locking head portion 23 thereby being
unable to reliably couple the plunger and the needle.
The present invention may be modified without departing from the
spirit and scope of the present invention. The present invention
provides a safety syringe adapted for intravenous injection, not
expected by the prior application. |