Safety syringe abstract
A safety syringe has a hollow barrel, a cord, a needle hub and
a plunger. The hollow barrel has a distal open end, a proximal open
end, a distal annular rib defined on the inside surface of the proximal
open end, a central annular rib defined on the inside surface of
the hollow barrel. The needle hub is detachably engaged inside the
proximal open end of the hollow barrel and has a needle mounted
on the needle hub. The plunger has a push rod and a seal mounted
on the push rod, and the seal is slidably mounted inside the hollow
barrel. The cord is connected to the needle hub and the seal. When
the safety syringe is used, the plunger pulls the cord connected
to the needle hub, so the needle hub with the needle is pulled inside
the hollow barrel to keep people from being hurt or infected by
an exposed.
Safety syringe claims
What is claimed is:
1. A safety syringe comprising a hollow barrel, a needle hub, a
plunger and a cord; the hollow barrel being cylindrical and having
a distal open end; a proximal open end; an inside surface; an outside
surface; an inner space; an annular flange defined radially around
and extending out from the distal open end; a lip defined radially
around and extending inward from the proximal open end of the hollow
barrel; a distal annular rib defined on the inside surface of the
hollow barrel near the lip; and a central annular rib defined inside
the hollow barrel equidistance between the open proximal end and
the open distal end; the needle hub detachable engaged to the distal
annular rib inside the proximal open end of the hollow barrel and
having an inside surface; an outside surface; a needle attached
to the outside surface of the needle hub and having a fluid passage
communicating with the inner space of the hollow barrel; a longitudinal
passage defined through the needle hub from the outside surface
to the inside surface to receive with one end of the needle; the
plunger mounted inside the hollow barrel having a push rod having
a proximal end; and a seal having an outside surface attached to
the proximal end of the push rod; and an inside surface; and the
cord having a seal end attached to the inside surface of the seal;
and a hub end attached to the inside surface of the needle hub,
wherein a distance between the proximal open end of the hollow barrel
and the central annular rib is greater than a combined length of
the needle hub and the needle.
2. The safety syringe as claimed in claim 1 wherein the cord has
a length being equal to a distance between the inside surface of
the needle hub and the inside surface of the seal when the needle
hub is engaged to the distal annular rib and the inside surface
of the seal abuts the central annular rib.
3. The safety syringe as claimed in claim 1 wherein the push rod
has a radial protrusions and further comprises multiple locking
grooves defined radially in the radial protrusions; and a plunger
lock being L-shaped and having a longitudinal leg having a free
end; a ball-prong formed around the free end of the longitudinal
leg and rotatably mounted in the annular flange around the distal
end of the hollow tube; and a limit-ring defined around the longitudinal
leg near the ball-prong; and a transverse leg selectively mounted
in the locking groove in the push rod to hold the plunger in position.
Safety syringe description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a syringe, and more particularly
to a safety syringe that can safely hold a used needle and prevent
the syringe from being used more than once.
2. Description of Related Art
A conventional syringe has a hollow barrel, a plunger and a needle
hub. The needle hubs of conventional syringes are easily inclined
during use so the needle hubs are difficult to retract into the
barrel. Due to contagious diseases, the needles of syringes and
even the hollow barrels and plungers, should not be used again and
should be discarded immediately after use. Also, to keep nurses,
doctors or workers who deal with discarded syringes from getting
injured or infected by used needles, a safety syringe is needed.
The conventional safety syringe often has a complex structure, so
to provide a simple and effective safe design for the needles of
syringes is still needed.
To overcome the shortcomings with conventional syringes, the present
invention provides a safety syringe to mitigate or obviate the aforementioned
problem.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a
safety syringe that has a simpler structure than the conventional
safety syringe and improves safety. The safety syringe in accordance
with the present invention comprises a hollow barrel, a cord, a
needle hub, a plunger and a plunger lock.
The hollow barrel has a distal open end, a proximal open end, a
distal annular rib and a central annular rib. The needle hub is
detachably mounted inside the proximal open end of the hollow barrel.
The plunger has a push rod and a seal mounted on the push rod and
is slidably mounted inside the hollow barrel. The cord connects
to the needle hub and the seal.
When using the safety syringe, the plunger can pull the cord connected
to the needle hub, so the needle hub can be pulled inside the hollow
barrel to keep the used needle from injuring or infecting a person.
Other objectives, advantages and novel features of the invention
will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of the safety syringe in
accordance with the present invention;
FIG. 2 is a side plan view in partial section of the safety syringe
in FIG. 1 with the plunger pressed into the hollow barrel;
FIG. 3 is an operational side plan view in partial section of the
safety syringe in FIG. 1 with a blood sample in the hollow barrel;
FIG. 4 is an operational side plan view in partial section of the
safety syringe in FIG. 1 with a test tube in the hollow barrel to
collect the blood sample; and
FIG. 5 is an operational side plan view of the safety syringe in
FIG. 1 with the push rod locked in position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIGS. 1 and 2 a safety syringe in accordance
with the present invention has a hollow barrel (10), a needle hub
(20), a plunger (30), a cord (40) and a plunger lock (60).
The hollow barrel (10) is cylindrical and has distal open end (not
numbered), a proximal open end (11), an inside surface (not numbered),
an outside surface (not numbered), an annular flange (12), a lip
(not numbered), a distal annular rib (13) and a central annular
rib (14). The annular flange (12) is defined radially around and
extends out from the distal open end of the hollow barrel (10).
The lip (not numbered) is defined radially around and extends inward
from the proximal open end (11) of the hollow barrel (10) so the
proximal open end (11) is smaller than the distal open end. The
distal annular rib (13) is defined on the inside surface of the
hollow barrel (10) near the lip. The central annular rib (14) is
defined on the inside surface of the hollow barrel (10) midway between
the proximal open end (11) and the distal open end of the hollow
barrel (10).
The needle hub (20) is mounted detachably inside the proximal open
end (11) of the hollow barrel (10) and has an inside surface (not
numbered), an outside surface (not numbered), a needle (21) and
a longitudinal passage (22). The needle hub (20) is made of a resilient
material. One end of the needle (21) is inserted into the longitudinal
passage (22) from the outside surface of the needle hub (20), and
the needle (21) has a fluid passage (not numbered) defined through
the needle (21). The fluid passage communicates with the inner space
of the hollow barrel (10).
The plunger (30) has a distal end (not numbered), a proximal end
(not numbered), a seal (31) and a push rod (32). The push rod (32)
has a distal end (not numbered), a proximal end (not numbered) and
radial protrusions (not numbered). The seal (31) has an inside surface
(not numbered) and an outside surface (not numbered). The distal
end of the push rod (32) is attached to the outside surface of the
seal (31), and the seal (31) is slidably mounted in the hollow barrel
(10). The push rod (32) has multiple locking grooves (33) defined
radially in the radial protrusions.
The cord (40) has a seal end (not numbered) and a hub end (not
numbered). The seal end of the cord (40) is attached to inside surface
of the seal (31), and the hub end of the cord (40) is attached to
the inside surface of the needle hub (20). The length of the cord
(40) is equal to a distance between the inside surface of the needle
hub (20) and the inside surface of the seal (31) when the need hub.
(20) is engaged with the distal annular rib (13) and the seal abuts
the central annular rib (14). Furthermore, a distance between the
proximal open end (11) of the hollow barrel (10) and the central
annular rib (14) is greater than a combined length of the needle
hub (20) and the needle (21) so the needle (21) will be inside the
hollow barrel (10) when the needle hub (20) engages the central
annular rib (14).
The plunger lock (60) is L-shaped and has a longitudinal leg (61)
and a transverse leg (64). The longitudinal leg (61) has a free
end, a ball-prong (62) and a limit-ring (63). The ball-prong (62)
is formed around the free end of the longitudinal leg (61). The
limit-ring (63) is formed around the longitudinal leg (61) of the
plunger lock (60) near the ball-prong (62). The ball-prong (62)
of the plunger lock (60) is rotatably mounted in the annular flange
(12).
With reference to FIGS. 2 and 3 the plunger (30) is pulled toward
the distal open end of the hollow barrel (10) after the needle (21)
is inserted into a patient's vein to take a blood sample (70). As
the seal (31) and the cord (40) are pulled, the blood sample (70)
is drawn into the hollow barrel (10) between the seal (31) and the
needle hub (20). When the seal (31) moves past the central annular
ring (14), drawing the blood sample (70) is finished.
With reference to FIGS. 4 and 5 the needle (21) is removed from
the patient's vein, and the plunger (30) is pulled toward the distal
open end of the hollow barrel (10). The moving plunger (30) pulls
the cord (40) and disengages the needle hub (20) from the distal
annular rib (13). The plunger (30) continues to pull the needle
hub (20) and the blood sample (70) trapped between the seal (31)
and the needle hub (20) until the needle hub (20) engages the central
annular rib (14). A test tube (80) with an open end (not numbered)
is used to collect the blood sample (70). When the needle (21) of
the needle hub (20) is totally inside the hollow barrel (10), the
open end of the test tube (80) is inserted into the hollow barrel
(10) through the proximal open end (11) to collect the blood sample
(70). The blood sample (70) is injected into the test tube (80)
by pressing the plunger (30). After the blood sample (70) has been
injected into the test tube (80), the transverse leg (64) of the
plunger lock (60) is pivoted into a corresponding locking groove
(33) to ensure that the needle (21) is neither pulled nor pushed
out of the hollow barrel (10). Then the test tube (80) is removed
from the hollow barrel (10) and capped. The safety syringe can protect
people from getting stabbed or infected by the used needle (21)
and prevent secondary use of the safety syringe.
Even though numerous characteristics and advantages of the present
invention have been set forth in the foregoing description, together
with details of the structure and function of the invention, the
disclosure is illustrative only, and changes may be made in detail,
especially in matters of shape, size, and arrangement of parts within
the principles of the invention to the full extent indicated by
the broad general meaning of the terms in which the appended claims
are expressed. |