Safety syringe abstract
A safety syringe includes: a plunger slidably held in a syringe
cylinder having a flexible coupling rod normally longitudinally
formed at a central portion of the plunger, and a needle device
detachably secured in a front portion of the syringe cylinder having
a tilting hole inclinedly formed in a rear portion of the needle
device, whereby upon finishing the injection of the syringe by engaging
the flexible coupling rod with the tilting hole to couple the used
needle device with the plunger, and upon a rearward retraction of
the plunger with the coupled needle device into the syringe cylinder,
the flexible coupling rod will automatically resiliently restore
to inclinedly bias the coupled needle device within the cylinder
to prevent outward protruding of the used needle device for safety
protection.
Safety syringe claims
I claim:
1. A safety syringe comprising: a syringe means including a syringe
cylinder for filling liquid medicine therein and defining a longitudinal
axis at a longitudinal center of said cylinder; a needle device
detachably secured in a front portion of said syringe cylinder having
a tilting hole inclinedly formed in a rear portion of said needle
device; and a plunger means having a plunger secured on a plunger
rod slidably held in said syringe cylinder, having a flexible coupling
rod formed on a front portion of said plunger and normally longitudinally
aligned with said longitudinal axis of said cylinder, whereby upon
finishing an injection of the liquid medicine in said cylinder to
engage said flexible coupling rod with said tilting hole to couple
said needle device (as used) with said plunger, and upon a retraction
of said plunger coupled with said needle device into said cylinder,
said flexible coupling rod will automatically resiliently restore
to inclinedly bias said needle device within said cylinder to prevent
an outward protruding of said needle device.
2. A safety syringe according to claim 1 wherein said syringe
means includes: said syringe cylinder having an interior for filling
the liquid medicine therein, a sleeve portion formed on a front
portion of the cylinder, a shoulder portion formed in between the
cylinder and the sleeve portion, a rear flange formed on a rear
end portion of the cylinder, and an annular extension annularly
formed on an inside wall of the cylinder adjacent to the rear flange.
3. A safety syringe according to claim 1 wherein said needle device
includes: a hollow needle having a needle hole formed through the
needle, a shank portion secured with the hollow needle, a packing
ring annularly retained on the shank portion and engaged with an
annular groove recessed in a sleeve portion formed on said cylinder,
and a tilting hole inclinedly formed in a rear portion of the shank
portion for engaging said flexible coupling rod having an axis formed
at a center of the tilting hole and defining an acute angle between
the axis and said longitudinal axis of the syringe cylinder which
is coaxial with a needle axis of the needle, with the tilting hole
fluidically communicated with the needle hole in the needle.
4. A safety syringe according to claim 3 wherein said tilting
hole in said shank portion includes a plurality of annular engaging
portions concentrically formed on an inside wall of the tilting
hole to be engaged with a plurality of rings concentrically formed
on said flexible coupling rod of the plunger means.
5. A safety syringe according to claim 4 wherein said annular
engaging portion is selected from: a ring groove annularly recessed
in the tilting hole, and at least a ratchet tooth annularly formed
on an inside wall of the tilting hole.
6. A safety syringe according to claim 1 wherein said plunger
means includes: said plunger secured on a front end portion of said
plunger rod, said flexible coupling rod made of flexible elastic
materials and protruding forwardly from the plunger to be slightly
tapered forwardly and normally restoring forwardly to by coaxially
aligned with the longitudinal axis defined at the longitudinal center
of the syringe cylinder when the plunger means is held in said syringe
cylinder, a circular disk perpendicularly formed on a front portion
of the plunger rod for retaining the plunger which is engaged on
an engaging head portion formed on a front portion of the circular
disk.
7. A safety syringe according to claim 6 wherein said plunger
means further includes: at least a ratchet tooth formed on a rear
portion of the circular disk formed on the front portion of the
plunger rod, whereby upon a rearward pulling of the plunger rod,
the ratchet tooth will be retarded against an annular extension
formed in the cylinder for preventing a rearward releasing of the
plunger means from the cylinder when the plunger means is coupled
with the needle device as used.
8. A safety syringe according to claim 7 wherein said ratchet
tooth is an annular ratchet tooth annularly formed on a front portion
of the plunger rod.
Safety syringe description
BACKGROUND OF THE INVENTION
[0001] A conventional safety syringe such as a "Simplified
Safety Syringe with Retractable Self-biased Needle" of U.S.
Pat. No. 5328475 may inclinedly retract a used needle into a syringe
cylinder by engaging an arrowhead portion 301 of a coupling member
30 formed on a plunger 31 with a biasing socket 27 (27a) recessed
in a rear portion of a needle device 2. Whenever coupling the arrowhead
portion 301 of the plunger into the biasing socket 27 in the needle
device 2 it will require a "great" force to pass the
arrowhead portion 301 through a narrow throat area between the port
231 and the conical-shaped socket 27 in order to be inserted into
the socket 27 thereby "transferring" such a "great"
force when coupling the arrowhead portion 301 with the socket 27
to the patient's body to cause his or her painful feeling.
[0002] The present inventor has found the drawbacks of the conventional
safety syringe and invented the present safety syringe which can
be ergonomically operated.
SUMMARY OF THE INVENTION
[0003] The object of the present invention is to provide a safety
syringe including: a plunger slidably held in a syringe cylinder
having a flexible coupling rod normally longitudinally formed at
a central portion of the plunger, and a needle device detachably
secured in a front portion of the syringe cylinder having a tilting
hole inclinedly formed in a rear portion of the needle device, whereby
upon finishing the injection of the syringe by engaging the flexible
coupling rod with the tilting hole to couple the used needle device
with the plunger, and upon a rearward retraction of the plunger
with the coupled needle device into the syringe cylinder, the flexible
coupling rod will automatically resiliently restore to inclinedly
bias the coupled needle device within the cylinder to prevent outward
protruding of the used needle device for safety protection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is an illustration showing the plunger means separated
from the syringe means secured with the needle device in accordance
with the present invention.
[0005] FIG. 2 is an illustration when finishing the injection of
the present invention.
[0006] FIG. 3 is an illustration showing an automatic tilting of
a used needle of the present invention.
[0007] FIG. 4 shows the ratchet teeth formed on the plunger means
of the present invention.
DETAILED DESCRIPTION
[0008] As shown in the drawing figures, 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.
[0009] 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 a shoulder portion
13 formed in between the cylinder 11 and the sleeve portion 12
a rear flange (or handle) 14 formed on a rear end portion of the
cylinder 11 and an annular extension 15 annularly formed on an
inside wall of the cylinder adjacent to the rear flange 14.
[0010] The sleeve portion 12 includes: a sleeve hole 121 longitudinally
formed through the sleeve portion 12 an annular seat portion 122
annularly formed in a front portion of the sleeve hole 121 and
an annular groove 123 annularly recessed in the sleeve hole 121.
[0011] The needle device 2 includes: a hollow needle 21 having
a needle hole 20 formed through the needle 21 a shank portion 22
secured with the hollow needle 21 a packing ring 23 annularly retained
on the shank portion 22 and engaged with the annular groove 123
recessed in the sleeve portion 12 and a tilting hole 24 inclinedly
formed in a rear portion of the shank portion 22 having an axis
240 formed at a center of the tilting hole 24 defining an acute
angle A between the axis 240 and a longitudinal axis X of the syringe
cylinder 11 which is coaxial with the needle axis 200 of the needle
21 with the tilting hole 24 fluidically communicated with the needle
hole 20 in the needle 21.
[0012] The shank portion 22 is further formed with an annular shoulder
portion 221 to be engaged with the annular seat portion 122 formed
in the sleeve portion 12 to retard a forward releasing of the shank
portion 22 from the sleeve portion 12 when subjected to the liquid
pressure during the injection.
[0013] The tilting hole 24 includes a plurality of annular engaging
portions 241 concentrically formed on (or in) the hole 24 to be
engaged with a plurality of rings 321 concentrically formed on a
flexible coupling rod 32 of the plunger means 3 which will be further
described hereinafter.
[0014] The annular engaging portion 241 may be a ring groove annularly
recessed in the tilting hole 24 or at least a ratchet tooth annularly
formed on an inside wall of the tilting hole 24.
[0015] However, the number of the annular engaging portions 241
may be one or two preferably, but not limited in this invention.
The tilting hole 24 should have an enough depth in order to snugly
engage the elongate coupling rod 32 of the plunger means 3 for a
reliable coupling of the needle device 2 with the plunger means
3 after finishing the injection.
[0016] The plunger means 3 includes: a plunger 31 secured on a
front end portion of a plunger rod 30 a flexible coupling rod 32
made of flexible elastic materials having a proper elasticity and
rigidity and protruding forwardly from the plunger 31 to be slightly
tapered forwardly and normally restoring forwardly to by coaxially
aligned with the longitudinal axis X defined at a longitudinal center
of the syringe cylinder 11 when the plunger means 3 is held in said
syringe cylinder 11 a circular disk 33 perpendicularly formed on
a front portion of the plunger rod 30 for retaining the plunger
31 which is also engaged on an engaging head portion 34 formed on
a front portion of the circular disk 33.
[0017] The flexible coupling rod 32 includes a plurality of rings
321 concentrically formed on the rod 32 for snugly engaging the
annular engaging portions 241 concentrically formed in the tilting
hole 24 when the flexible coupling rod 32 is inserted into the titling
hole 24 whereby upon retraction of the plunger 31 as coupled with
the needle device 2 into the syringe cylinder 11 the used needle
device 2 will be tilted automatically as shown in FIG. 3.
[0018] The principles of the present invention are explained and
described in detail as follows:
[0019] Upon finishing of the injection, the flexible coupling rod
32 is inserted into the tilting hole 24 in the shank portion 22
of the needle device 2 by gradually "bending" the coupling
rod 32 into the tilting hole 24 to thereby store the elastic energy
of the rod 32.
[0020] After retracting the plunger 31 coupled with the needle
device 2 into the cylinder 11 the flexible coupling rod 32 will
restore by its self resilience or elasticity to be longitudinally
aligned with the axis X of the cylinder 11.
[0021] However, since the tilting hole 24 of the needle device
2 is snugly engaged with the coupling rod 32 which is now longitudinally
restored as shown in FIG. 3 the shank portion 22 and the complete
needle device 2 will then be tilted from the axis X for an inclined
angle, i.e. the acute angle A.
[0022] The used needle 21 will not be further protruded outwardly
as retarded against the shoulder portion 13 in the syringe, thereby
safely protecting the persons who may contact the syringes.
[0023] The present invention is superior to the prior art such
as U.S. Pat. No. 5328475 with the following advantages:
[0024] 1. The coupling rod 32 is elongate and slightly tapered
to be smoothly snugly engaged (coupled) with the tilting hole 24
in the needle device 2 without causing a great coupling force when
coupling the plunger 31 with the needle device 2 and thereby preventing
painful feeling of a patient as being injected.
[0025] 2. After retracting the used needle 21 as coupled with the
plunger 31 into the cylinder 11 the used needle will be "precisely"
biased inclinedly because a reliable coupling between the coupling
rod 32 and the tilting hole 24 having a longer distance and bigger
area existing in the frictional engagement (coupling) between the
rod 32 and the hole 24.
[0026] 3. This invention is especially suitable for making small-volume
syringe such as 1 cc syringe. The coupling rod 32 can be manufactured
more easily since it is not a conventional conical-shaped arrowhead
structure which will be made more difficultly when the size of the
syringe becomes smaller.
[0027] The plunger means 3 (FIGS. 3 4) further includes: at least
a ratchet tooth 35 formed on a rear portion of the circular disk
33 formed on the front portion of the plunger rod 30 whereby upon
a rearward pulling of the plunger rod 30 the ratchet tooth 35 will
be retarded (or locked) against the annular extension 15 for preventing
a rearward releasing of the plunger means 3 once coupled with the
used needle device 2 from the cylinder 11.
[0028] The ratchet tooth (or teeth) 35 as recessed or formed in
a rear portion of the circular disk 33 of the plunger means 3 can
be plural ratchet teeth 35 (the number and shapes of teeth being
not limited) circumferentially formed in a front portion of the
plunger rod 30 as shown in FIG. 3 or may be formed as an annular
ratchet tooth 35 annularly formed on a front portion of the plunger
rod 30 as shown in FIG. 4.
[0029] An arcuate front edge portion may be formed on the circular
disk 33 adjacent the front end portion of the plunger rod 30 in
order to 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.
[0030] The present invention may be modified without departing
from the spirit and scope of the present invention. |