Safety syringe abstract
A safety syringe has a hollow barrel, a plunger, a connector, a
plug and a needle hub. The plunger includes a socket to mount the
connector. The connector has a needle connector protruded from the
connector to connect with the needle hub. When the plunger is pushed
toward the needle hub the first time, the needle hub of the connector
is hidden in the socket and the plunger can not connect with the
needle hub. When the plunger is pulled back and the syringe is full
of medical solution, the needle hub of the connector protrudes from
the socket. Pushing the plunger again toward the needle hub can
connect the plunger and the needle hub together and the needle hub
can retract back in the hollow barrel.
Safety syringe claims
What is claimed is:
1. A safety syringe comprising: a hollow barrel having a proximal
open end; a distal open end; an inside surface; and a distal annular
rib defined inside the hollow barrel and near the distal open end,
and having an inner radius; a plunger slidably mounted inside the
hollow barrel and having a push rod having a proximal end, a distal
end and a peripheral side; and a socket formed on the proximal end
of the push rod and having a radius smaller than that of the distal
annular rib in the hollow barrel, and having a distal end; a proximal
closed end; a longitudinal axis; a sidewall; a central chamber formed
along the longitudinal axis of the socket and having an inner wall
and an annular rib formed on the inner wall of the central chamber
and near the distal end of the socket; a first slot formed in the
sidewall of the socket and communicated with the central chamber;
a second slot formed in the sidewall of the socket, opposite to
the first slot and communicated with the central chamber; and two
recesses formed in the sidewall of the socket and in communication
with the second slot, and forming a positive limit in the distal
end of the socket, wherein the two recesses and the second slot
form a second chamber larger than the first slot; a connector having
a length slightly smaller than that of the central chamber in the
socket and mounted into the socket, and having a cylindrical body
mounted into the central chamber of the socket, and having an outside
surface, a proximal end and a distal end; a first limiting protrusion
extending perpendicular outward from the proximal end of the body,
and defined corresponding to and moveably mounted in the first slot;
a second limiting protrusion extending perpendicular outward from
the proximal end of the body, and defined corresponding to and moveably
mounted in the second chamber of the socket, wherein the first limiting
protrusion and the second limiting protrusion each have an outer
concentric circumference between that of the hollow barrel and the
distal annular rib of the hollow barrel and moveable between the
proximal closed end and the positive limit of the socket; an annular
limiting rib extending radially outward from the proximal end of
the body and between the first limiting protrusion and the second
limiting protrusion; and a needle connector extending from the distal
end of the body, wherein the needle connector is retained in the
central chamber of the socket when the first limiting protrusion
and the second limiting protrusion move freely between the proximal
closed end and the annular rib of the socket and the needle connector
protrudes from the central chamber of the socket when the first
limiting protrusion and the second limiting protrusion move freely
between the annular rib and the positive limit of the socket; a
plug abutted to the distal end of the socket on the plunger and
slidably mounted inside the hollow barrel; and a needle hub mounted
in the proximal open end of the hollow barrel and having a connecting
tube having a distal end; a proximal end; a connecting chamber formed
in the distal end of the connecting tube and having a proximal open
end, wherein the connecting chamber has a radius larger than that
of the needle connector of the connector; and a proximal annular
rib extended radially inward from the proximal open end of the connecting
chamber, wherein the proximal annular rib has an inner radius smaller
than that of the needle connector of the connector; and a needle
attached to the proximal end of the connecting tube and having a
central passage.
2. The safety syringe as claimed in claim 1 wherein the distal
annular rib in the hollow barrel is formed in non-continuous fragment.
3. The safety syringe as claimed in claim 1 wherein the push rod
further comprises a V-shape groove defined radially in the push
rod.
4. The safety syringe as claimed in claim 1 wherein the socket
further comprises a protrusion protruded from the distal end of
the socket and has a radius smaller than that of the socket, and
the central chamber of the socket extends through the protrusion
and the plug is mounted around the protrusion on the socket of the
plunger.
5. The safety syringe as claimed in claim 1 wherein a neck is
formed between the needle connector and the body.
Safety syringe description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a syringe, and more particularly
to a safety syringe that can retract the used needle.
[0003] 2. Description of Related Art
[0004] A conventional syringe has a hollow barrel, a plunger and
a needle hub. Due to contagious diseases, the needle of the syringe
and even the hollow barrel and the plunger, should not be used again
and should be discarded immediately after use. Also, to keep nurses,
doctors or health workers who deal with discarded syringes from
getting injured or infected by used needles, a safety syringe is
needed. In particular, manufacturers have focused on syringes with
retractable needles so that once the syringe has been used, the
contaminated needle is entirely housed within the barrel whereby
the chance of infection through accidental pricking is eliminated.
[0005] A conventional safety syringe disclosed in Taiwan Pat. No.
356013 comprises a hollow barrel, a plunger and a needle hub. The
plunger has a connector formed on one end of the plunger to connect
with the needle hub. The connector has a protrusion. The needle
hub comprises a recess and an annular rib. The recess has a distal
closed end and a proximal open end. The annular rib extends radially
inward from the proximal open end of the recess. The protrusion
of the connector can be clipped by the annular rib of the needle
hub to connect the plunger and the needle hub together. When the
plunger is pushed to the needle hub, the plunger with the connector
becomes connected with the needle hub to retract the needle hub
into the hollow barrel.
[0006] However, the conventional safety syringe often retracts
the needle hub before use. Since the medical personnel will customarily
push the plunger toward the needle hub to eject air before a medical
solution is drawn into the safety syringe, the medical personnel
often forgets that with the safety syringe the plunger can not be
pushed to the front most end at this time. Thus, the plunger will
connect with the needle hub and the needle hub will retract back
in the hollow barrel. In this situation, the safety syringe can
no longer be used and the safety syringe is wasted.
SUMMARY OF THE INVENTION
[0007] The main objective of the present invention is to provide
a safety syringe that can pull back the used needle yet prevent
the user from pulling back the needle before use.
[0008] To achieve the objective, a safety syringe in accordance
with the present invention comprises a hollow barrel, a plunger,
a connector, a plug and a needle hub. The hollow barrel comprises
a distal annular rib formed inside the hollow barrel. The plunger
comprises a socket to mount the connector. The connector comprises
a needle connector protruded from the connector to connect with
the needle hub. When the plunger is pushed toward the needle hub
the first time, the needle hub of the connector is hidden in the
socket and the plunger can not connect with the needle hub. When
the plunger has been pulled back and the syringe is full of the
medical solution, the needle hub of the connector will protrude
from the socket by the distal annular rib. Pushing the plunger again
toward the needle hub ejects the medicine into a patient and once
the plunger meets and connects with the needle hub the combined
plunger and needle hub can be retracted in the hollow barrel.
[0009] Further benefits and advantages of the present invention
will become apparent after a careful reading of the detailed description
with appropriate reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a safety syringe in accordance
with the present invention;
[0011] FIG. 2 is an exploded perspective view of the safety syringe
in FIG. 1;
[0012] FIG. 3 is a perspective view of the safety syringe in FIG.
1 showing a plunger pushed into a hollow barrel in the first time;
[0013] FIG. 4 is a cross sectional side plan view of the partial
safety syringe in FIG. 1 showing the plunger pulled back from the
hollow barrel;
[0014] FIG. 5 is a cross sectional side plan view of the partial
safety syringe in FIG. 1 showing a needle connector protruded from
a socket of the plunger;
[0015] FIG. 6 is a perspective view of the safety syringe in FIG.
5 showing the needle connector protruded from the socket of the
plunger;
[0016] FIG. 7 is a cross sectional side plan view of the partial
safety syringe in FIG. 5 showing the needle connector connected
with a needle hub;
[0017] FIG. 8 is a perspective view of the syringe in FIG. 7 showing
the needle hub retracted back into a hollow barrel; and
[0018] FIG. 9 is a perspective view of the syringe in FIG. 8 showing
the plunger is broken and the needle hub is retained in the hollow
barrel.
DETAILED DESCRIPTION OF THE INVENTION
[0019] With reference to FIGS. 1 and 2 a safety syringe in accordance
with the present invention comprises a hollow barrel (10), a plunger
(20), a connector (30), a plug (40) and a needle hub (50).
[0020] The hollow barrel (10) is cylindrical and has a proximal
open end (not numbered), a distal open end (not numbered), a lip
(12), an inside surface (not numbered), an annular flange (11) and
a distal annular rib (14). The lip (12) 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. The annular flange
(11) extends radially out from the distal open end of the hollow
barrel (10). The distal annular rib (14) is defined inside the hollow
barrel (10) and near the distal open end. The distal annular rib
(14) has an inner radius. Preferably, the distal annular rib (14)
could be formed in non-continuous fragment.
[0021] The plunger (20) has a push rod (21), a socket (22) and
a seal (not numbered), and is slidably mounted inside the hollow
barrel (10). The push rod (21) has a proximal end (not numbered),
a distal end (not numbered) and a peripheral side (not numbered).
Preferably, the push rod (21) further comprises a V-shape groove
(210) defined radially in the push rod (21). The seal is attached
to the distal end of the push rod (21).
[0022] The socket (22) is formed on the proximal end of the push
rod (21), and has a distal end, a proximal closed end (262), a longitudinal
axis (not numbered), a sidewall (not numbered), a central chamber
(24), a first slot (25), a second slot (26) and two recesses (261).
The central chamber (24) is formed along the longitudinal axis of
the socket (22) and has an inner wall (not numbered) and an annular
rib (241). The annular rib (241) is formed radially on the inner
wall of the central chamber (24) and near the distal end of the
socket (22). The first slot (25) is formed in the sidewall of the
socket (22) and communicates with the central chamber (24). The
second slot (26) is formed in the sidewall of the socket (22), opposite
to the first slot (25) and communicates with the central chamber
(24). The two recesses (261) are formed in the sidewall of the socket
(22) and in communication with the second slot (26), and form a
positive limit (263) in the distal end of the socket (22). The two
recesses (261) and the second slot (26) form a second chamber (not
numbered). The second chamber is larger than the first slot (25).
Preferably, the two recesses (261) are fan-shaped. More preferably,
the socket (22) further comprises a protrusion (23) protruded from
the distal end of the socket (22). The protrusion (23) has a radius
smaller than that of the socket (22) and the central chamber (24)
of the socket (22) extends through the protrusion (23). Furthermore,
the radius of the socket (22) is smaller than the inner radius of
the distal annular rib (14) in the hollow barrel (10).
[0023] The connector (30) is mounted into the socket (22) and has
a body (31), an annular limiting rib (310), a needle connector (32),
a first limiting protrusion (33) and a second limiting protrusion
(34). The body (31) is cylindrical and mounted into the central
chamber (24) of the socket (22), and has an outside surface (not
numbered), a proximal end (not numbered) and a distal end (not numbered).
The needle connector (32) extends from the distal end of the body
(31). Preferably, a neck (320) is formed between the needle connector
(32) and the body (31). The first limiting protrusion (33) and the
second limiting protrusion (34) extend perpendicular outward from
the proximal end of the body (31) and are defined corresponding
to the first slot (25) and the second chamber of the socket (22)
respectively. The first limiting protrusion (33) and the second
limiting protrusion (34) each have an outer concentric circumference
between an inner radius of the hollow barrel (10) and the distal
annular rib (14) of the hollow barrel (10). The first limiting protrusion
(33) and the second limiting protrusion (34) move freely in the
first slot (25) and the second chamber respectively and between
the proximal closed end (262) and the positive limit (263) of the
socket (22). The annular limiting rib (310) extends radially outward
from the proximal end of the body (31) and between the first limiting
protrusion (33) and the second limiting protrusion (34). The connector
(30) has a length slightly smaller than that of the central chamber
(24) in the socket (22). The needle connector (32) will hide in
the central chamber (24) of the socket (22) when the first limiting
protrusion (33) and the second limiting protrusion (34) move freely
between the proximal closed end (262) and the annular rib (241)
of the socket (22). The needle connector (32) will protrude from
the central chamber (24) of the socket (22) when the first limiting
protrusion (33) and the second limiting protrusion (34) move freely
between the annular rib (241) and the positive limit (263) of the
socket (22).
[0024] The plug (40) is abutted to the distal end of the socket
(22) on the plunger (20) and slidably mounted inside the hollow
barrel (10). Preferably, the plug (40) is mounted around the protrusion
(23) on the socket (22) of the plunger (20).
[0025] With further reference to FIG. 7 the needle hub (50) is
mounted in the proximal open end of the hollow barrel (10) and has
a connecting tube (51) and a needle (52). The connecting tube (51)
has a distal end (not numbered), a proximal end (not numbered),
a connecting chamber (510) and a proximal annular rib (511). The
connecting chamber (510) is formed in the distal end of the connecting
tube (51) and has a proximal open end. The connecting chamber (510)
has a radius larger than that of the needle connector (32) of the
connector (30). The proximal annular rib (511) extends radially
inward from the proximal open end of the connecting chamber (510).
The proximal annular rib (511) has an inner radius smaller than
the radius of the needle connector (32) of the connector (30). The
needle (52) is attached to the proximal end of the connecting tube
(51) and has a central passage (not shown).
[0026] With further reference to FIGS. 3 and 4 the plunger (20)
with the connector (30) and the plug (40) will firstly extend into
the hollow barrel (10) before using the safety syringe. When the
plunger (20) is pushed toward the proximal open end of the hollow
barrel (10), the first limiting protrusion (33) and the second limiting
protrusion (34) will be blocked by the annular rib (14). Continuously
pushing the plunger (20) will expand the annular rib (14) to let
the first limiting protrusion (33) and the second limiting protrusion
(34) pass through the annular rib (14) and to the proximal open
end of the hollow barrel (10). In this situation, the needle connector
(32) of the connector (30) is hidden in the central chamber (24)
of the socket (22) so the needle connector (32) will not connect
to the connecting tube (51) of the needle hub (50). After the plunger
(20) is pushed to the proximal end of the hollow barrel (10), any
air in the hollow barrel (10) is ejected. When the plunger (20)
is pulled toward the distal open end of the hollow barrel (10),
solution can be drawn through the needle hub (50) into the hollow
barrel (10).
[0027] With further reference to FIGS. 5 and 6 since the radiuses
of the first limiting protrusion (33) and the second limiting protrusion
(34) are larger than that of the distal annular rib (14) of the
hollow barrel (10), the first limiting protrusion (33) and the second
limiting protrusion (34) are blocked by the distal annular rib (14)
of the hollow barrel (10). When pulling the plunger (20) continuously
toward the distal open end of the hollow barrel (10), the annular
rib (241) of the socket (22) passes through the first limiting protrusion
(33) and the second limiting protrusion (34). The first limiting
protrusion (33) and the second limiting protrusion (34) will move
between the annular rib (241) and the positive limit (263). In this
situation, the needle connector (32) and the neck (320) of the connector
(30) protrude from the central chamber (24) of the socket (22).
[0028] With further reference to FIG. 7 the plunger (20) is pushed
toward the proximal open end of the hollow barrel (10) again to
eject the solution from the hollow barrel (10) into a patient. Since
the needle connector (32) protrudes from the central chamber (24)
of the socket (22), pushing the plunger (20) to the proximal open
end of the hollow barrel (10) will let the needle connector (32)
insert into the connecting chamber (510) of the connecting tube
(51). The neck (320) of the needle connector (32) on the connector
(30) is clipped by the proximal annular rib (511) of the connecting
tube (51).
[0029] With further reference to FIGS. 8 and 9 the used needle
(52) of the needle hub (50) is retracted into the hollow barrel
(10) after use. Pulling the plunger (20) toward the distal open
end of the hollow barrel (10) will pull the needle hub (50) back
into the hollow barrel (10). After the groove (210) of the plunger
(20) exits the hollow barrel (10), the groove (210) of the plunger
(20) permits the protruding portion of the plunger (20) to be snapped
off whereby the needle hub (50) is retained inside the hollow barrel
(10).
[0030] The safety syringe in accordance with the present invention
can allow the plunger (20) to travel into the hollow barrel (10)
and not connect with the needle hub (50) in the first time. When
the safety syringe has been used to treat a patient, the plunger
(20) can connect with the needle hub (50) to let the needle hub
(50) retract back in the hollow barrel (10). The present invention
can avoid operating error and prevent wastage of syringes.
[0031] Although the invention has been explained in relation to
its preferred embodiment, many other possible modifications and
variations can be made without departing from the spirit and scope
of the invention as hereinafter claimed is to be understood. |