Safety syringe abstract
A safety syringe has a hollow barrel, a plug, 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 inside the proximal open
end, a central annular rib defined inside the hollow barrel. The
plug is detachably mounted inside the proximal open end of the hollow
barrel. The needle hub is mounted in the plug. The plunger has a
push rod and a seal mounted on the push rod and is received inside
the hollow barrel. The cord connects to the plug and the seal. When
using the safety syringe, the plunger pulls the cord connected to
the plug, so the needle hub is pulled inside the hollow barrel to
keep people from being hurt by an exposed needle.
Safety syringe claims
What is claimed is:
1. A safety syringe comprising a hollow barrel, a plug, 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 annular flange formed radially around extending
out from the distal open end; a lip formed radially around and extending
inward from the proximal open end of the hollow barrel; a proximal
annular rib defined inside the hollow barrel near the lip and a
central annular rib defined inside the hollow barrel; the plug detachably
engaged with the proximal annular rib inside the proximal open end
of the hollow barrel and having a top surface; a bottom surface;
a hub recess being tapered and defined through the plug from the
top surface to the bottom surface; and a needle hole defined through
the plug; the needle hub mounted in the plug and having a connecting
tube being tapered and having a distal end and a proximal end; and
a needle attached to the proximal end of the connecting tube and
having a central passage; the plunger having a push rod being mounted
inside the hollow barrel and having a proximal end; and a seal having
a top surface attached to the proximal end of the push rod; and
a bottom surface; and the cord connected between the plug and the
plunger and having a top end attached to the bottom surface of the
seal; and a bottom end attached to the top surface of the plug;
wherein a distance between the proximal end of the hollow barrel
and the central annular rib is greater than a combined length of
the needle hub and the plug.
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 safety syringes to mitigate or obviate the aforementioned
problems.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a
safety syringe that has a simpler structure than a conventional
safety syringe and improves safety. The safety syringe in accordance
with the present invention has a hollow barrel, a plug, a needle
hub, a plunger and a cord. The hollow barrel has a distal open end,
a proximal open end, a proximal annular rib, a central annular rib.
The plug is detachably mounted inside the proximal open end of the
hollow barrel. The needle hub is mounted to the plug. 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 plug
and the seal. When using the safety syringe, the plunger can pull
the cord connected to the plug, 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 of the safety syringe in FIG. 1;
FIG. 3 is an operational side plan view of the safety syringe in
FIG. 1;
FIG. 4 is an operational plan view of the safety syringe in FIG.
1; and
FIG. 5 is a side plan view of the safety syringe in FIG. 1 when
the push rod is positioned.
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 plug (20),
a needle hub (50), 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 proximal annular rib (13) and an 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 radially
inward from the proximal open end of the hollow barrel (10) so the
proximal open end (11) is smaller than the distal open end. A proximal
annular rib (13) is defined inside the hollow barrel (10) near the
lip. The central annular rib (14) is defined inside the hollow barrel
(10) equidistance between the open proximal end (11) and the open
distal end.
The plug (20) is detachably engaged with the distal annular rib
(13) inside the proximal open end (11) of the hollow barrel (10)
and has a top surface (not numbered), a bottom surface (not numbered),
a hub recess (21) and a needle hole (22). The hub recess (21) is
defined through the plug (20) from the top surface to the bottom
surface. The hub recess (21) is tapered. The needle hole (22) is
defined through the plug (20).
The needle hub (50) is mounted in the plug (20) and has a connecting
tube (51) and a needle (52). The connecting tube (51) is tapered
and has a distal end (not numbered) and a proximal end (not numbered).
The needle (52) is attached to the proximal end of the connecting
tube (51) and has a central passage (not shown). The needle hub
(50) is inserted through the top surface of the plug (20) and is
mounted inside the hub recess (21).
The plunger (30) has a seal (31) and a push rod (32). The push
rod (32) has a distal end (not numbered), a proximal end (not numbered)
and a peripheral side (not numbered). The seal (31) has a top surface
(not numbered) and a bottom surface (not numbered). The proximal
end of the push rod (32) is attached to the top surface of the seal
(31) and is mounted in the hollow barrel (10). The push rod (32)
has multiple locking grooves (33) defined radially in the push rod
(32).
The cord (40) has a top end (not numbered), a bottom end (not numbered)
and a length. The top end of the cord (40) is attached to the bottom
surface of the seal (31), and the bottom end of the cord (40) is
attached to the bottom surface of the plug (20). The length of the
of the cord (40) is equal to a distance between the top of the plug
(20) and the bottom of the seal (31) when the plug (20) is engaged
with the distal annular rib (13) and the bottom of seal (31) abuts
the central annular rib (14). Furthermore, a distance between the
proximal end (11) of the hollow barrel (10) and the central annular
rib (14) is greater than a combined length of the needle hub (50)
and the plug (20) so the needle (52) will be inside the hollow barrel
(10) when the plug (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. The limit-ring
(63) is defined around the longitudinal leg (61) of the plunger
lock (60) near the ball-prong (62). The ball-prong (62) is rotatably
mounted in the annular flange (12).
With reference to FIGS. 2 and 3 the plunger (30) is pulled toward
the distal end of the hollow barrel (10) after the needle (52) of
the safety syringe is put 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 plug (20). When the seal (31) moves past the central
annular rib (14), drawing the blood sample (70) is finished.
With reference to FIGS. 4 and 5 the needle (52) 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 plug (20) from the distal annular
rib (13). The plunger (30) continues to pull the plug (20), the
needle hub (50) and the blood sample (70) trapped between the seal
(31) and the plug (20) until the plug (20) engages the central annular
rib (14). A test tube (80) with an open end is used to collect the
blood sample (70). When the needle (52) of the needle hub (50) 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
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
(52) 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
by the used needle (52) and prevents 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. |