Safety syringe abstract
A safety syringe includes: a hollow needle assembly having a hollow
needle portion detachably coupled to a shank portion embedded in
a sleeve portion of a syringe and having a needle head portion formed
on a rear portion of the shank portion, and a plunger slidably held
in the syringe and having a biasing socket 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
into the syringe for obliquely biasing the needle portion for preventing
re-protrusion of the needle outwardly, the shank portion having
a pair of bars engageable with any one of the two wedged extensions
formed in a cylindrical recess in the sleeve portion for preventing
a rotation of the shank portion in the sleeve portion for reliably
coupling the hollow needle portion on the shank portion.
Safety syringe claims
I claim:
1. A safety syringe 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 formed in a front
portion of the cylinder contracted and tapered forwardly from the
cylinder, and a shoulder portion formed in a front portion of the
cylinder between the syringe cylinder and the sleeve 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 aligned with the syringe axis when
mounting the needle assembly on the syringe means for normally injection
use; and
a plunger means including: a plunger reciprocatively held in the
syringe cylinder, a biasing socket 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 converging rearwardly from
the plunger front surface for communicating with the biasing socket
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 when retracting the needle assembly
within the syringe cylinder, and a plunger rod connected with the
plunger;
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 protrduding
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;
the improvement which comprises:
said shoulder portion of said syringe means having a shallow cylindrical
recess recessed forwardly from said shoulder portion to be communicated
with said cylindrical socket of said sleeve portion, said shallow
cylindrical recess having two wedged extensions unsymmetrically
disposed on said shallow cylindrical recess, with each said wedged
extension having a tip portion tapered rearwardly; and
said enlarged cylindrical portion of said shank portion of said
hollow needle assembly having a pair of bars diametrically formed
on said enlarged cylindrical portion and engageable with one said
wedged extension on said shallow cylindrical recess, whereby upon
engagement of said bars of said shank portion with one said wedged
extension of said sleeve portion, said shank portion will not be
rotated in said sleeve portion for a reliable coupling of said hollow
needle portion on said shank portion.
Safety syringe description
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5431631 granted to the same inventor of this application
discloses a safety syringe allowing a retraction of a used needle
assembly into the syringe cylinder for preventing its outward re-protrusion
and also providing a hollow needle portion 21 which may be detachably
mounted on a shank portion 22 outside the syringe cylinder 11.
However, when coupling the hollow needle portion 21 on said shank
portion 22 of the needle assembly 2 the shank portion 22 may be
free rotated within the sleeve portion 12 of the syringe means 1
thereby influencing a reliable coupling of the hollow needle portion
21 on the shank portion 22 and causing unstable mounting of the
needle assembly on the syringe means.
The present inventor has found such a drawback and made an improvement
for overcoming the free-rotation problem of the shank portion in
the sleeve portion of the syringe means.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a safety syringe
including: a hollow needle assembly having a hollow needle portion
detachably coupled to a shank portion embedded in a sleeve portion
of a syringe and having a needle head portion on a rear portion
of the shank portion, and a plunger slidably held in the syringe
and having a biasing socket 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 retraction into the syringe
for obliquely biasing the needle portion for preventing a re-protrusion
of the needle outwardly, the shank portion having a pair of bars
engageable with any one of the two wedged extensions formed in a
cylindrical recess in the sleeve portion for preventing a rotation
of the shank portion in the sleeve portion for reliably coupling
the hollow needle portion on the shank portion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional drawing showing all parts in construction
of the present invention;
FIG. 1A is a partial sectional drawing of a front portion of the
present invention;
FIG. 1B is a perspective view of the front portion of the present
invention;
FIG. 2 is a perspective view of the hollow needle assembly of the
present invention;
FIG. 3 is a sectional drawing showing a practical application of
the present invention for injection;
FIG. 4 is a sectional drawing of the present invention showing
a finished condition after the injection;
FIG. 5 is an illustration showing a self-biased needle when retracted
in the syringe cylinder in accordance with the present invention;
and
FIG. 6 is an illustration showing a bent needle in a syringe for
preventing its outward re-protrusion in accordance with the present
invention.
As shown in FIGS. 1-6 the present invention comprises: a syringe
means 1 a hollow needle assembly 2 mounted 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 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 formed in a front portion of the cylinder 11 contracted and tapered
forwardly from the cylinder 11 a shoulder Portion 13a formed in
a front portion of the cylinder 11 between the cylinder 11 and the
sleeve portion and a syringe handle 14 formed on a rear end portion
of 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 a shallow cylindrical recess
125 which is 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 (FIG. 5)
in the sleeve portion 12 as gradationally tapered forwardly from
the shoulder portion 13a in the syringe means 1 the shallow cylindrical
recess 125 the cylindrical socket 124 the truncated-cone-shaped
socket 123 the ring groove 122 and the sheath opening 121 and
two wedged extensions 126 unsymmetrically disposed on and perpendicularly
formed on the shallow cylindrical recess 125 with each extension
126 having a tip portion 126a tapered rearwardly from the shallow
cylindrical recess 125o
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 protrduding
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; a pair of bars 225 diametrically formed
on the enlarged cylindrical portion 224 to be tangentially engageable
with anyone of the two wedged extensions 126 on said cylindrical
recess 125 for preventing a loosening rotation of the shank portion
22 when rotatably coupling the hollow needle portion 21 on the shank
portion 22; 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 in a rear
portion of the enlarged cylindrical portion 224 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 aligned with the syringe axis 100 when mounting the
needle assembly 2 on the syringe means 1 for normally 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 body,
The plunger means 3 includes: a plunger 31 reciprocatively held
in the syringe cylinder 11 a biasing socket 32 generally arcuate
shaped and 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 converging rearwardly from the
plunger front surface 310 for communicating with the biasing socket
32 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 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 needle axis 200 and syringe axis
100 when normally mounting the needle assembly 2 on the syringe
means 1.
When using the present invention for injection use, the plunger
31 is pushed forwardly to drive the liquid medicine 4 into a patient's
skin through the hollow needle portion 21 as shown in FIG. 3. 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. 4 as urged (D) by the rod 35.
When retracting (R) the plunger 31 and the coupled needle portion
21 the needle portion 21 will be automatically biased as shown
in FIG. 5 and while re-protruding of the needle portion 21 forwardly
(F) as shown in FIG. 6 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 a conventional safety syringe
of U.S. Pat. 5232458 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. The shank portion (22) has its bars (225) engageable
with any wedged extension 126 to be "locked" in the syringe
means 1 for preventing a rotative loosening in the syringe means
1 when rotatably coupling (T) the hollow needle portion (21) on
the shank portion (22) as shown in FIG. 1 and 1A.
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.
4. If the retracted needle 21 in the syringe cylinder 11 is not
biased with a larger biasing angle, a further accidental reprotrusion
of the needle outwardly may be prevented since the tip end 211 of
the needle 21 may be retarded on plural locations, namely: the shoulder
portion 13a, the cylindrical socket 124 and the annular groove
122 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.
The present invention may be modified without departing from the
spirit and scope of this invention. |