Safety syringe abstract
A safety syringe for intravenous injection, includes: a hollow
needle assembly having a hollow needle portion detachably coupled
to a shank portion embedded in a sleeve portion eccentrically formed
on a syringe and having a needle head portion formed on a rear portion
of the shank portion, and a plunger straightly slidably held in
the syringe without being rotatable and having a biasing socket
eccentrically recessed in the plunger for engaging the needle head
portion of the needle assembly for a coupling of the needle assembly
with the plunger for a retraction together into the syringe for
obliquely biasing the needle portion for preventing re-protrusion
of the needle outwardly, thereby allowing a variety of needles of
different sizes to be replaceably mounted on the shank portion outside
the syringe for a convenient mounting of the needle on the syringe.
Safety syringe claims
I claim:
1. A safety syringe for intravenous injection comprising: a syringe
means including: a syringe cylinder for filling liquid medicine
therein, a syringe axis longitudinally defined in a central portion
of the syringe cylinder, a sleeve portion eccentrically formed in
a front portion of the cylinder contracted and tapered forwardly
from a shoulder portion formed in a front portion of the cylinder
between the syringe cylinder and the sleeve portion, and a flat
bore portion longitudinally formed in said cylinder to have a cross
section of secant circular shape of said bore portion;
a hollow needle assembly including a hollow needle portion detachably
connected with a shank portion secured in the sleeve portion of
said syringe means, and a needle head portion connected to the shank
portion by a hollow neck portion, a central injection hole formed
in said needle head portion, and a venting slot formed in the neck
portion, said central injection hole and said venting slot communicating
with a central through hole longitudinally formed through the shank
portion and communicating with the needle hole formed in said hollow
needle portion when coupling the hollow needle portion on said shank
portion, and a needle axis defined in a central portion of the hollow
needle assembly and normally parallel with the syringe axis when
mounting the needle assembly on the syringe means for normal injection
use; and
a plunger means including: a plunger reciprocatively and straightly
held in the syringe cylinder, a biasing socket eccentrically recessed
rearwardly from a plunger front surface of the plunger having a
longitudinal axis defined at a center of the biasing socket to be
deviated from the syringe axis with an acute angle, a guiding port
eccentrically converging rearwardly from the plunger front surface
for communicating with the biasing socket and having a guiding port
center aligned with the needle axis of said needle assembly when
normally mounted on said syringe means for slidably guiding the
needle head portion rearwardly through the guiding port to be engaged
into the biasing socket for biasing the hollow needle portion obliquely
towards a side portion of the shoulder portion opposite to the sleeve
portion of the syringe means when retracting the needle assembly
within the syringe cylinder, and a plunger rod connected with the
plunger;
said plunger having a flat portion slidably straightly engageable
with said flat bore portion secantly formed in said cylinder for
preventing a free rotation of said plunger in said cylinder;
said sleeve portion including: a sheath opening formed in a front
end portion of the sleeve portion, a ring groove annularly recessed
in an inside wall of the sheath opening, a truncated-cone-shaped
socket tapered forwardly from a cylindrical socket recessed forwardly
from the shoulder portion of the syringe means and communicating
with the sheath opening, with the cylindrical socket having an inside
diameter larger than an inside diameter of a rear end portion of
the truncated-cone-shaped socket, and the sheath opening having
an inside diameter equal to an inside diameter of a front end portion
of the truncated-cone-shaped socket for forming a tapered through
hole in the sleeve portion as gradationally tapered forwardly from
the shoulder portion in the syringe means, the cylindrical socket,
the truncated-cone-shaped socket, the ringe groove and the sheath
opening; and
said hollow needle portion having a coupling sheath formed on a
rear portion of the hollow needle portion having a stem socket recessed
inwardly forwardly to communicate with the needle hole longitudinally
formed through the hollow needle portion and a female groove spirally
recessed in the stem socket; said shank portion having a hollow
truncated-cone-portion engageable with the truncated-cone-shaped
socket in the sleeve portion, a packing ring secured to a front
portion of the truncated cone portion and engageable with the ring
groove in the sleeve portion for retaining a front portion of the
shank portion in said sleeve portion, a hollow stem portion protruding
forwardly from the truncated cone portion having at least a male
projection circumferentially formed on the stem portion to be engageable
with the female groove recessed in the coupling sheath of the hollow
needle portion for detachably coupling the hollow needle portion
on the shank portion secured on the syringe means from outside the
syringe cylinder and an enlarged cylindrical portion formed on a
rear end portion of the shank portion engageable with the cylindrical
socket in the sleeve portion.
2. A safety syringe according to claim 1 wherein said syringe
means has a flat portion longitudinally formed on a bottom portion
of said syringe cylinder having a cross section of a secant circular
shape.
Safety syringe description
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5242402 to Long-Hsiung Chen disclosed a safety
syringe for intravenous injection including: an annular groove annularly
recessed in a front surface of a plunger slidably held in the syringe
to be engageable with a needle head portion formed on a rear portion
of a hollow needle eccentrically mounted in a front portion of the
syringe, with the annular groove having a longitudinal section formed
as a biasing socket engageable with the needle head portion for
biasing the needle obliquely within the syringe when retracting
the plunger and the needle into the syringe, thereby preventing
an outward protruding of the retracted needle for safety and hygienic
purpose.
However, such a conventional safety syringe may have the following
drawbacks:
1. When engaging the needle head portion 23 of the needle device
2 with the biasing socket of annular groove 32 of the plunger 31
for retracting a used needle into the syringe, the needle head portion
23 may still be released from the annular groove 32 to be accidentally
protruded outwardly through the tunnel 130 since the groove 32 is
concentrically recessed in the plunger 31 not a single round socket
for tightly engaging the needle head portion 23.
2. After retracting the needle in the syringe cylinder, the plunger
may still be rotated or twisted to re-protrude the retracted needle
outwardly to cause dangerous pricking since the plunger 31 can be
free rotational about the syringe axis 100 within the syringe means
1.
3. In order to repel the liquid medicine filled in the annular
groove 32 the extension 15 must be provided on a rear surface of
the front plug 13 for engaging the groove 32. If the extension 15
is engaged with the groove 32 too tightly, the plug 13 as coupled
with the plunger 31 straightly holding the needle 2 will be together
retracted inwardly into the cylinder 11 without biasing the needle
obliquely.
4. The needle 2 should be inserted through the plug in the syringe
cylinder to be mounted on the syringe to cause inconvenience. Also,
it can not be replaced with needles of different sizes from outside
the syringe.
The present inventor has found the drawbacks of the conventional
safety syringe and invented the present safety syringe with externally
connectable needle.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a safety syringe
for intravenous injection including: a hollow needle assembly having
a hollow needle portion detachably coupled to a shank portion embedded
in a sleeve portion eccentrically formed on a syringe and having
a needle head portion on a rear portion of the shank portion, and
a plunger having a cross section of secant circular shape to be
straightly slidably held in the syringe having a hollow bore portion
also made as a secant circular cross section slidably engageable
with the secant plunger and having a biasing socket recessed in
the plunger for engaging the needle head portion of the needle assembly
for ensuring a straight and sharp coupling of the needle assembly
with the plunger for retraction into the syringe for obliquely biasing
the needle portion for preventing a re-protrusion of the needle
outwardly, whereby a variety of needles of different sizes can be
replaceably mounted on the shank portion outside the syringe for
a convenient mounting of the needle on the syringe.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional drawing showing all parts in construction
of the present invention.
FIG. 2 is an exploded view of the present invention.
FIG. 3 is a perspective view of the present invention when assembled.
FIG. 4 is a cross sectional view of the present invention when
viewed from 4--4 direction of FIG. 3.
FIG. 5 is a perspective view of the hollow needle assembly.
FIG. 6 is a sectional drawing showing a practical application of
the present invention for injection.
FIG. 7 is a sectional drawing of the present invention showing
a finished condition after the injection.
FIG. 8 is an illustration showing a self-biased needle when retracted
in the syringe cylinder in accordance with the present invention.
FIG. 9 is an illustration showing a bent needle in a syringe for
preventing its outward re-protrusion in accordance with the present
invention.
DETAILED DESCRIPTION
As shown in FIGS. 1-9 the present invention comprises: a syringe
means 1 a hollow needle assembly 2 eccentrically mounted on the
syringe means 1 and a plunger means 3 straightly slidably held
in the syringe means 1.
The syringe means 1 includes: a syringe cylinder 11 having a hollow
bore portion 10 formed in the syringe cylinder 11 for filling liquid
medicine 4 therein and a syringe axis 100 longitudinally defined
in a central portion of the syringe cylinder 11 a sleeve portion
12 eccentrically formed in a front portion of the cylinder 11 contracted
and tapered forwardly from a shoulder portion 13a formed in a front
portion of the cylinder 11 between the cylinder 11 and the sleeve
portion 12 and a syringe handle 14 formed on a rear end portion
of the cylinder 11. The cylinder 11 has a flat portion 15 having
a cross section of secant circular shape and longitudinally formed
on an outside bottom portion of the cylinder 11. The bore 10 is
also formed with a flat bore portion 10a inside the cylinder 11.
The sleeve portion 12 includes: a sheath opening 121 formed in
a front end portion of the sleeve portion 12 a ring groove 122
annularly recessed in an inside wall of the sheath opening 121
a truncated-cone-shaped socket 123 tapered forwardly from a cylindrical
socket 124 recessed forwardly from the shoulder portion 13a of the
syringe means 1 and communicating with the sheath opening 121 with
the cylindrical socket 124 having an inside diameter larger than
an inside diameter of a rear end portion of the truncated-cone-shaped
socket 123 and the sheath opening 121 having an inside diameter
equal to an inside diameter of a front end portion of the truncated-cone-shaped
socket 123 thereby forming a tapered through hole 12a in the sleeve
portion 12 as gradationally tapered forwardly from the shoulder
portion 13a in the syringe means 1 the cylindrical socket 124
the truncated-cone-shaped socket 123 the ring groove 122 and the
sheath opening 121.
The hollow needle assembly 2 includes: a hollow needle portion
21 having a tip end 211 formed on a front end of the hollow needle
portion 21 a coupling sheath 212 formed on a rear portion of the
hollow needle portion 21 having a stem socket 213 recessed inwardly
forwardly to communicate with a needle hole 210 longitudinally formed
through the hollow needle portion 21 and a female groove 214 spirally
recessed in the stem socket 213: a shank portion 22 having a hollow
truncated-cone-portion 22a engageable with the truncated-cone-shaped
socket 123 in the sleeve portion 12 a packing ring 221 embedded
in an inner ring groove 221a annularly recessed in a front portion
of the truncated cone portion 22a and engageable with the ring groove
122 in the sleeve portion 12 a hollow stem portion 222 protruding
forwardly from the truncated cone portion 22a having at least a
male projection 223 circumferentially formed on the stem portion
222 to be engageable with the female groove 214 recessed in the
coupling sheath 212 of the hollow needle portion 21 for detachably
coupling the hollow needle portion 21 on the shank portion 22 secured
on the syringe means 1 from outside the syringe cylinder 11 and
an enlarged cylindrical portion 224 formed on a rear end portion
of the shank portion 22 engageable with the cylindrical socket 124
in the sleeve portion 12; and a needle head portion 23 connected
to the shank portion 22 by a hollow neck portion 24a and generally
shaped as a circular disk having a rear arcuate surface of the needle
head portion 23 and a central injection hole 231 formed therein
to communicate with a venting slot 24 formed in the neck portion
24a and to communicate with a central through hole 220 longitudinally
formed through the shank portion 22 and communicating with the needle
hole 210 when coupling the hollow needle portion 21 on the shank
portion 22 and a needle axis 200 defined in a central portion of
the hollow needle assembly 2 and normally parallel with the syringe
axis 100 when mounting the needle assembly 2 on the syringe means
1 for normal injection use. The liquid medicine 4 flows through
the central injection hole 231 the venting slot 24 the central
through hole 220 and the needle hole 210 to be injected into a patient's
vein or blood vessel.
The plunger means 3 includes: a plunger 31 reciprocatively and
straightly held in the syringe cylinder 11 with a flat portion 31a
secantly formed on a periphery of the plunger 31 slidably engageable
with the flat bore portion 10a for preventing a rotaton or twisting
of the plunger 31 in the cylinder 11 about the syringe axis 100
a biasing socket 32 generally arcuate shaped and eccentrically recessed
rearwardly from a plunger front surface 310 of the plunger 31 having
a longitudinal axis 321 defined at a center of the socket 32 to
be deviated from the syringe axis 100 with an acute angle A, a guiding
port 33 eccentrically converging rearwardly from the plunger front
surface 310 for communicating with the biasing socket 32 and having
a port center 331 normally aligned with the needle axis 200 of the
needle assembly 2 when mounted on the syringe means for slidably
guiding the needle head portion 23 rearwardly through the guiding
port 33 to be engaged into the biasing socket 32 for biasing the
hollow needle portion 21 obliquely to orient the tip end 211 towards
an angled wall portion 13b between the shoulder portion 13a and
the cylinder 11 opposite to the sleeve portion 12 when retracting
the needle assembly 2 within the hollow bore portion 10 a plunger
rod 35 connected with the plunger 31 by coupling a coupling member
36 formed on a front end of the rod 35 with a recess 34 recessed
in a rear portion of the plunger 31 and a rod handle 37 formed on
a rear end of the rod 35 for grasping use, and a plunger axis 300
longitudinally defined in a central portion of the plunger 31 and
the rod 35 to be aligned with the syringe axis 100 and to be parallel
to the needle axis 200 when normally mounting the needle assembly
2 on the syringe means 1.
The shapes of the needle head portion 23 and the biasing socket
32 are not limited in this invention.
When using the present invention for injection use, the plunger
31 is pushed forwardly to drive the liquid medicine 4 into a patient's
vein through the hollow needle portion 21 as shown in FIG. 6. After
the medicine 4 is exhausted, the needle head portion 23 will be
engaged with the biasing socket 32 in the plunger 31 as shown in
FIG. 7 as urged by the rod 35.
When retracting the plunger 31 and the coupled needle assembly
2 the needle assembly 2 will be automatically biased as shown in
FIG. 8 and while re-protruding of the needle portion 21 forwardly
as shown in FIG. 9 the tip end 211 will be bent, without being
protruded outwardly for preventing pricking on the user, the cleaners,
or medical personnels.
The present invention is superior to the conventional safety syringe
of U.S. Pat. No. 5242402 with the following advantages:
1. The hollow needle portion 21 may be detachably coupled to the
shank portion 22 by rotating (T) the coupling sheath 212 to engage
the female groove 214 in the sheath 212 with the projection 223
on the stem portion 222 of the shank portion 22 to conveniently
install the needle portion 21 on the syringe means 1 outside the
syringe means.
2. A variety of needles of different sizes may be replaceably mounted
on the syringe means 1 for optional choices.
3. The structure is simplified to thereby reduce the production
cost such as by eliminating the plug 13.
4. The tip end 211 is always biased towards the angled wall portion
13b opposite to the sleeve portion 12 to be far away from the through
hole 12a so that the retracted needle assembly 2 will not be re-protruded
outwardly, thereby absolutely ensuring a safety treatment of the
retracted needle.
5. The truncated-cone shaped shank portion 22 of the needle assembly
2 will enforce a stable engagement with the through hole 12a in
the sleeve portion 12 helpful for a smooth injection when urged
by the plunger 31 for boosting liquid medicine into a patient during
the injection.
6. The flat portion 15 of the syringe cylinder 11 will help a smooth
intravenous injection on an ergonomic point of view.
7. The socket 32 is a "single hole", rather than an annular
groove, thereby being stably engageable with the needle head portion
23 for a reliable coupling and retraction of the plunger 31 with
the needle assembly 2 into the cylinder 11.
The present invention may be modified without departing from the
spirit and scope of this invention. |