Safety syringe abstract
The retractable safety syringe for drawing back a soft piston therein
is comprised of a needle set, a cylindrical barrel and a plunger.
A retractable mechanism is provided for pulling the needle set into
it. The plunger is provided on the front end thereof with a soft
piston, and with an activating piece to activate the retractable
mechanism or with a connecting piece connectable to the retractable
mechanism. When in assembling, the soft piston of a plunger is pushed
to the top point of a space provided for injection, before deformation
of the piston, an activating piece or a connecting piece on the
plunger does not activate or connect with the retractable mechanism,
and when the plunger is pushed by a force larger than a preset amount,
the piston is compressed to deform and to render the activating
piece to activate or connect with the retractable mechanism to pull
the needle set into the cylindrical barrel automatically or manually.
Safety syringe claims
1. A retractable safety syringe for drawing back a soft piston,
said syringe comprises: a needle set, at least including a needle
and a needle seat, being provided thereunder with a retractable
mechanism for pulling said needle set into it; a cylindrical barrel,
the upper part thereof being formed a needle set socket, the lower
part thereof being a space provided for injection, said needle set
being connected onto said needle set socket; a plunger being inserted
into said space provided for injection in said cylindrical barrel
from the rear end of said cylindrical barrel, and being provided
on the front end thereof with a piston and with a connecting piece
adapted to connecting to said retractable mechanism, said piston
being a soft piston to be pushed and compressed to deform; when
in assembling, the top point of said space provided for injection
before deformation of said piston prevents said connecting piece
on said plunger from connecting with said retractable mechanism,
and when said plunger is pushed by a force larger than a preset
amount, said piston is compressed to deform and to displace said
connecting piece to connect with said retractable mechanism of said
needle set.
2. The retractable safety syringe for drawing back a soft piston
as claimed in claim 1 wherein said retractable mechanism of said
needle set is provided on a base of said needle set with a connecting
portion to make connection with said connecting piece of said plunger.
3. The retractable safety syringe for drawing back a soft piston
as claimed in claim 2 wherein said connecting portion is an engaging
ratchet formed at the central portion of said base, said connecting
piece of said plunger is a hook portion protruded from the center
of the front end of said piston, the bottom of said hook portion
is contacted with the top surface of said piston, said hook portion
is provided on the front end of a piston shaft, said piston shaft
supports said piston and is provided on the front end of said plunger.
4. The retractable safety syringe for drawing back a soft piston
as claimed in claim 3 wherein an extended protrusion is formed
on the front end of said hook portion, when said hook portion is
pierced into said engaging ratchet of said base of said needle set,
said extended protrusion is extended into the space where injection
liquid is.
5. The retractable safety syringe for drawing back a soft piston
as claimed in claim 1 wherein the scale mark of injection liquid
at said top point of said space provided for injection is zero.
6. A retractable safety syringe for drawing back a soft piston,
said syringe comprises: a needle set, at least including a needle
and a needle seat, being provided therein with an automatic retractable
mechanism for pulling said needle set into it; a cylindrical barrel,
the upper part thereof being formed a needle set socket, the lower
part thereof being a space provided for injection, said needle set
being connected onto said needle set socket; a plunger being inserted
into said space provided for injection in said cylindrical barrel
from the rear end of said cylindrical barrel, and being provided
on the front end thereof with a piston and with an activating piece
to activate said automatic retractable mechanism, said piston being
a soft piston to be pushed and compressed to deform; when in assembling,
the top point of said space provided for injection before deformation
of said piston prevents said activating piece from activating said
automatic retractable mechanism, and when said plunger is pushed
by a force larger than a preset amount, said piston is compressed
to deform and to move forwards said activating piece on said plunger
to activate said automatic retractable mechanism to pull said needle
set into said cylindrical barrel.
Safety syringe description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the invention
[0002] The present invention is related to a retractable safety
syringe with a soft piston; and especially to such a syringe in
which the piston is made of elastic material in order that when
in drawing in and injecting medicine, the front end face of the
piston can be pushed to the top end of the cylindrical barrel of
the syringe to allow accurate taking out of the medicine following
the indicating scale marks and pressing the medicine out stably;
and after injecting, the piston can be deformed by pressing, so
that a connecting piece or an activating piece provided on a plunger
can connect or activate a retractable mechanism provided on a needle
set, and the needle set can be retracted into the cylindrical barrel.
The syringe suits various cylindrical barrels of syringes or similar
structures.
[0003] 2. Description of the Prior Art
[0004] Since the medical science was widely developed, medicine
injection with syringes has been the fastest and most effective
way of treatment, and it is widely adopted in the medical field.
However, syringes are generally discarded after use, it becomes
the main point of designing for the goal of preventing accidental
stabbing and infecting medical workers in dealing with waste syringes,
and the goal of reducing the volumes of discarded syringes. Thereby,
various retractable safety syringes have been developed.
[0005] Referring to FIG. 1 showing the structure of a conventional
manual retractable safety syringe, wherein a plunger 10 can be pulled
or pushed in a cylindrical barrel 30; the plunger 10 is provided
on the front end thereof with a piston 11 and a hook portion 21
the hook portion 21 is protruded from the front end of piston 11
to form a neck portion 20 with a length "b" therebetween.
A connecting portion "a" is provided on the bottom of
a needle set 1 when the plunger 10 is pushed forwards to the top
point, the hook portion 21 can pierce into the connecting portion
"a" to form a hooking state therewith, thereby the needle
set 1 can be pulled back into the cylindrical barrel 30.
[0006] The connecting portion "a" of the needle set 1
shown in FIG. 1 is located at the center of the bottom of the needle
set 1; the hook portion 21 is also located at the center of the
plunger 10 to form a connecting piece. However, there are other
retractable mechanisms with different pulling back modes for conventional
manual retractable safety syringes. For example, the connecting
portion of the needle set can be provided on the exterior surface
of the base of the needle set, and the connecting piece of the plunger
can be provided on the exterior surface of the plunger to be able
to mutually hook or engage.
[0007] Whichever style a manual retractable safety syringe is,
generally, to avoid the connecting portion "a" of the
plunger 10 to be pushed inadvertently forwards to the top point
before discarding the cylindrical barrel 30 of the syringe, a measure
is adopted to render the plunger 10 to be moved only when a sufficient
force is exerted thereon to make connection of the connecting piece
with the connecting portion "a" at the moment when the
front end of the plunger 10 contacts the base of the needle set
1.
[0008] There are also automatic retractable safety syringes taking
advantage of the restoring force of springs, such automatic retractable
safety syringes shall have their activating pieces provided on the
plungers also moved by forces to overcome resistances of predetermined
values before the spring retractable mechanisms are activated.
[0009] Medical workers generally pull backwards the push rods on
the rear ends of plungers of syringes to draw air into the cylindrical
barrels, and then pierce needles into the medicine bottles and push
forwards the plungers. The air drawn into the cylindrical barrels
is injected into the medicine bottles, and the plungers are pulled
back following the indicating marks to draw required amount of medicine
into the cylindrical barrels. And when in injection for patients,
to avoid remaining of the medicine in the cylindrical barrels, the
medical workers generally will push the push rods forwards to the
top points. Hence, whichever of the manual or automatic retractable
safety syringes they are, during the process of injection, forces
must be exerted to overcome the resistances in connecting and activating
of the retractable mechanisms finally.
[0010] The above stated conventional retractable safety syringes
always have following defects:
[0011] 1. As shown in FIG. 1 there is a distance "b"
(i.e., the length of the neck portion 20) left between the piston
11 and the hook portion 21 thereby, when in taking injection liquid
before injection, the amount of the injection medicine taken will
be reduced. That is to say, the medical workers must increase the
amount taken when in drawing the medicine for injection in order
to avoid reducing of the treatment efficiency due to insufficiency
of medicine; and if the medicine for injection is insufficient due
to neglect of the medical workers, the treatment efficiency will
also be lowered to influence development in treating patients.
[0012] 2. When in injecting medicine for a patient with a syringe
by a medical worker, by the fact that the front end of the piston
11 is unable to reach the position where the top mark indication
line "A" showing the amount of 0 ml is, while there is
still injection liquid in the space "b" between the piston
11 and the hook portion 21 the medical worker shall exert a force
to push the plunger 10 to the top point, such force added abruptly
during injecting may create a pain feeling of a patient.
[0013] In view of these, the inventor of the present invention
studied and developed a retractable safety syringe for drawing back
a soft piston that can accurately draw in the required medicine
and can stably push the plunger to the top point; and when the needle
is drawn out of the body of a patient after injection, a force can
be exerted to push forwards and draw back the plunger.
SUMMARY OF THE INVENTION
[0014] The primary object of the present invention is to provide
a retractable safety syringe for drawing back a soft piston, with
the soft piston and such a designing having the distance between
the front end of the piston and the connecting piece or the activating
piece of the plunger reduced, the amount of medicine taken can be
accurate, so that when in injection, no abrupt adding of force is
required to push the plunger to the top point, and a patient can
be prevented from getting a pain feeling.
[0015] The secondary object of the present invention is to provide
a retractable safety syringe that can reduce the residual medicine
amount in the cylindrical barrel of the syringe.
[0016] To get the above objects, the present invention is comprised
of a needle set, a cylindrical barrel and a plunger. An automatic
retractable mechanism or a manual retractable mechanism is provided
thereon the needle set for pulling the needle set into the cylindrical
barrel. The plunger is provided on the front end thereof with a
soft piston, and with an activating piece to activate the automatic
retractable mechanism for the needle set or with a connecting piece
connectable to the manual retractable mechanism for the needle set.
The plunger is inserted into the cylindrical barrel from the rear
end of the latter, the cylindrical barrel is a hollow barrel, and
the upper part thereof is formed a needle set socket to allow insertion
connecting of the needle set, while the lower part thereof is a
space provided for injection. The piston is made of elastic material;
the connecting piece or the activating piece on the front end of
the plunger has its bottom surface exactly protruded out of the
front end face of the piston. When in the state of injection, the
upper surface of the piston is contacted with the bottom surface
of the connecting piece or the activating piece. Hence when in injection,
the plunger is stably pushed to the top point to completely eject
all the medicine; and when in discarding, the piston is pushed to
move the connecting piece or the activating piece forwardly to be
released from contact with the upper surface of the piston and to
push it into the retractable mechanism to activate the automatic
retractable mechanism or to connect it with the connecting portion
of the manual retractable mechanism, to thereby pull the needle
set down into the cylindrical barrel.
[0017] The present invention will be apparent in its features and
structure after reading the detailed description of the preferred
embodiment thereof in reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a sectional view showing the structure of a conventional
syringe;
[0019] FIG. 2 is an analytic perspective view showing the elements
of the embodiment of the present invention;
[0020] FIG. 3 is a sectional view of the embodiment of the present
invention;
[0021] FIG. 4 is a sectional view showing drawing in the liquid
for injection by the embodiment of the present invention;
[0022] FIG. 5a is a sectional view showing a hook portion engages
an engaging ratchet in the embodiment of the present invention;
[0023] FIG. 5b is an enlarged sectional view showing the hook portion
engages the engaging ratchet in the embodiment of the present invention;
[0024] FIG. 6 is a sectional view of the embodiment of the present
invention showing drawing back of a needle set;
[0025] FIG. 7a is a coordinate plane showing the force in injecting
medicine from N ml to 0 ml by the retractable safety syringe of
the present invention;
[0026] FIG. 7b is a coordinate plane showing the force in injecting
medicine from N ml to 0 ml by the retractable safety syringe of
the conventional syringe;
[0027] FIG. 8 is a schematic sectional view showing another embodiment
having an extended protrusion on the top end of the hook portion
of the present invention;
[0028] FIG. 9 is an enlarged sectional view showing the hook portion
of FIG. 8 is engaged with an engaging ratchet of the present invention.
[0029] FIG. 10 is a partly sectional view showing a further example
of the prevent invention applying to a needle set comprising a needle,
needle seat and retractable adapter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] Referring to FIG. 2 showing an embodiment of a manual retractable
safety syringe of the present invention having a soft piston, the
syringe is comprised of a needle set 40 a cylindrical barrel 50
and a plunger 60.
[0031] Wherein, the needle set 40 is comprised of a needle 41 and
a needle seat 42 for fixing therein the needle 41; the needle seat
42 is in the form of a hollow pipe and is provided therein with
an engaging ratchet 43. A hollow shaft of the needle 41 and the
central portion of the needle seat 42 are both hollow and are communicated
with the central portion of the engaging ratchet 43 such hollow
portions form a passing space for medicine.
[0032] The cylindrical barrel 50 is a hollow cylinder, a space
52 for injection is provided on the rear part of the cylindrical
barrel 50 and scale marks (taking ml as the unit) indicating the
amounts of medicine are printed on the external surface of the cylindrical
barrel 50. The cylindrical barrel 50 is formed on the front end
thereof a needle set socket 51 to receive the needle seat 42 of
needle set 40.
[0033] The plunger 60 is comprised of a piston 61 and a pusher
rod 62; the piston 61 is made of elastic material. The pusher rod
62 is provided on the front end thereof with a piston shaft 621
(referring to FIG. 3); the piston shaft 621 is provided on the top
end thereof with a hook portion 622 the piston 61 is slipped over
the piston shaft 621.
[0034] As shown in FIGS. 2 3 the piston 61 in this embodiment
is made of elastic material, the piston shaft 621 on the front end
of the pusher rod 62 has a length equal to the thickness of the
piston 61; so that when the piston 61 is extended over the piston
shaft 621 only the hook portion 622 of the piston shaft 621 protrudes
out of the piston 61 to render the bottom end of the hook portion
622 to contact the piston 61. Referring to FIGS. 3 4 when the
pusher rod 62 is pulled back to draw in medicine for injection,
the front end face of the piston 61 is at the position where the
top scale mark "A" (indicating 0 ml) is, hence medicine
can be drawn in with accurate amount.
[0035] When in injecting medicine, by virtue that the front end
face of the piston 61 contacts with the bottom end of the hook portion
622 the plunger 60 can be stably pushed to a top point to completely
eject all the medicine; and when in discarding a syringe, as shown
in FIGS. 5a and 5b, the piston 61 is pushed and compressed to deform,
thereby the hook portion 622 of the piston shaft 621 is released
from contact with the upper surface of the piston 61 to in turn
push forwards the engaging ratchet 43 of the needle seat 42 and
to engage with the engaging ratchet 43. And the needle set 40 can
be pulled down into the cylindrical barrel 50.
[0036] And referring to FIGS. 7a and 7b that respectively provide
coordinate planes showing the force in injecting medicine by the
retractable safety syringe of the present invention and of the conventional
syringe, wherein the Y axis indicates the force that a medical worker
exerts, while the X axis indicates the residual amount of medicine,
the starting point represents that the amount of medicine in the
cylindrical barrel is N ml, the amount is gradually reduced to 0
ml.
[0037] The retractable safety syringe of the present invention
and the conventional retractable safety syringe are both poured
in with N ml medicine. When in injection, before the residual amount
of medicine is b ml, the retractable safety syringes of the present
invention and the conventional one are exerted with forces of the
same amount; and when injection is proceeded to having the residual
amount of medicine of b ml, as for the conventional retractable
safety syringe, the hook portion of the plunger thereof is pushed
upwardly to contact the engaging ratchet on the bottom of the needle
seat and is hindered from forwarding, the medical worker must put
a force to eject the remaining medicine, increasing of force makes
pain of a patient; while as for the present invention, force is
stably exerted, no additional force is necessary to push the piston
to the top point but injecting of medicine can be completed.
[0038] Referring to FIGS. 8 9 in the above stated embodiment
of the present invention, an extended protrusion 623 can also be
formed on the front end of the hook portion 622 so that when the
hook portion 622 of the piston shaft 621 is pierced into the engaging
ratchet 43 of the needle seat 42 to form an engagement state, the
extended protrusion 623 formed on the front end of the hook portion
622 can be extended deeply into the needle seat 42 to occupy the
space therein, thereby the residual amount of injection liquid can
be further lowered.
[0039] In the drawings of the present invention, although the needle
set socket 51 of the cylindrical barrel 50 is in the state of having
a reduced diameter, if the needle set 40 is of the structure of
which the needle 41 is changeable, the needle set socket 51 of the
cylindrical barrel 50 can also have its bottom enlarged to be in
the form of a straight barrel to allow the needle set socket 51
and the cylindrical barrel 50 to have the same inner diameter, but
the needle set 40 can be in the same way inserted for connection.
[0040] FIG. 10 is shown a further application of the present invention,
wherein the needle set 70 is comprised of a needle 71 a needle
seat 72 and a retractable adapter 73 having a retractable mechanism,
such as an engaging ratchet 731.
[0041] And in the above stated drawings and specification, the
engaging ratchet 43 on the base of the needle set 40 forms a connecting
portion of a manual retractable mechanism, in which the shape of
the arrangement the engaging ratchet 43 and the arrangement that
the engaging ratchet 43 is located at the center of the base of
the needle set 40 only form an embodiment of such a manual retractable
safety syringe. In fact, the structure of the soft piston and the
connecting piece of the plunger of the present invention can be
applied to any manual retractable safety syringe having a connecting
piece of the plunger and a connecting portion of the needle set
of any of various shapes and at any of various locations. The structure
of the soft piston and the connecting piece of the plunger of the
present invention can also be applied to an automatic retractable
safety syringe; in which the connecting piece of the plunger forms
the activating piece to activate the retractable mechanism provided
on the needle set.
[0042] In conclusion, the present invention surely provides an
improved structure for the connecting piece or the activating piece
for a piston and a retractable mechanism for use on a retractable
syringe; the present invention thereby is industrially practical.
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