Syringe needle abstract
A syringe with needle retraction arrangement is adapted for automatically
retracting the hollow needle into a hollow plunger after use so
as to prevent the used needle from contacting with anybody. The
syringe provides a closure seat at one end of a hollow plunger,
wherein when the closure seat is intentionally pushed towards a
mounting seat affixed in a mounting portion of a hollow barrel,
a pusher member, which is detachably connect with the closure seat,
presses a tip head of a hollow needle as well as an O-ring thereon
to slide towards a needle hub to compress a compression spring to
store a resilient force. When the engagement of the O-ring between
the ring groove of the tip head and the annular wall of the O-ring
passage is released, the resilient force stored in the compression
spring will upwardly push the tip head of the hollow needle to press
against the pusher member and breaks its connection with the closure
seat to open an entrance aperture provided on the closure seat,
so that the hollow needle, the pusher member and the compression
spring will all be retracted into the receiving cavity of the hollow
plunger automatically.
Syringe needle claims
What is claimed is:
1. A syringe, comprising:
a hollow barrel having an open end portion, a needle mounting portion,
and a tubular needle hub extending from said needle mounting portion
to provide a needle passageway therethrough and an end shoulder
radically extended inwardly from a free end of said needle mounting
portion;
a hollow needle having a tissue penetrating end and a tip end thereof
affixed with a cylindrical tip head which has a shallow ring groove
provided thereon, wherein said tip head of said hollow needle is
disposed in said needle mounting portion with said tissue penetrating
end penetrating through said needle passageway;
a compression spring surrounding said hollow needle and having
two ends pressing against said end shoulder of said needle hub and
said tip head of said hollow needle respectively;
an O-ring removably resting around said ring groove of said tip
head;
a mounting seat, which is integrally affixed within said needle
mounting portion, having an O-ring passage coaxially aligned with
said needle passageway of said needle hub, a top end portion of
said O-ring passage reducing diameter to form a stopper shoulder
against which said O-ring abuts, wherein a circular gap is formed
between said ring groove of said tip head of said hollow needle
and an annular wall of said O-ring passage, said circular gap having
a width smaller than a diameter of said O-ring so as to compress
said O-ring between said stopper shoulder and said ring groove and
to securely mount said tip head in said O-ring passage; and
a hollow plunger adapted to travel through said hollow barrel,
said hollow plunger having an outer close end and an inner end inserted
in said hollow barrel through said open end portion, a closure seat
being connected to said inner end of said hollow plunger so as to
define a receiving cavity inside said hollow plunger, said closure
seat having an entrance aperture positioned above said O-ring passage
of said mounting seat, said entrance aperture being covered by a
pusher member which is circumferentially connected with said entrance
aperture in such a manner that said pusher member is detached to
open said entrance aperture when a predetermined pound of urging
force is applied to said pusher member;
thereby, when said closure seat of hollow plunger is intentionally
pushed towards said mounting seat, said pusher member presses said
tip head as well as said O-ring thereon to slide towards said needle
hub and further compress said compression spring to store a resilient
force, moreover when said O-ring is pressed to travel through of
said O-ring passage, said resilient force of said compression spring
increases to a force larger than said predetermined pound of urging
force, so that the engagement of said O-ring between said ring groove
of said tip head and said annular wall of said O-ring passage is
released, and said resilient force stored in said compression spring
upwardly pushes said tip head of said hollow needle to press against
said pusher member until said entrance aperture is opened, so that
said hollow needle, said pusher member and said compression spring
are retracted into said receiving cavity of said hollow plunger.
2. A syringe as recited in claim 1 wherein said pusher member further
comprises a pushing stud protruded towards said mounting seat, said
pushing stud having a size adapted to enter said O-ring passage
and directly apply pressing force onto said tip head of said needle
when said plunger is inwardly pushed towards said mounting seat.
3. A syringe as recited in claim 2 wherein a plurality of pressing
wings are spacedly extended from said pushing stud downwardly and
adapted for inserting into said top end portion of said O-ring passage
for pressing down said O-ring when said pusher member is pushed
downwardly.
4. A syringe as recited in claim 2 wherein a sealing groove is
provided around said inner end for holding a ring shaped sealing
member thereon, said sealing member fitting in said clearance between
an inner annular wall of said barrel and said sealing groove so
as to ensure air tight and sealing effect of said plunger.
5. A syringe as recited in claim 3 wherein a sealing groove is
provided around said inner end for holding a ring shaped sealing
member thereon, said sealing member fitting in said clearance between
an inner annular wall of said barrel and said sealing groove so
as to ensure air tight and sealing effect of said plunger.
6. A syringe as recited in claim 2 wherein said closure seat further
comprises a spacer which is disposed below a bottom surface of said
closure seat and surrounded said pushing stud of said pusher member.
7. A syringe as recited in claim 3 wherein said closure seat further
comprises a spacer which is disposed below a bottom surface of said
closure seat and surrounded said pushing stud of said pusher member.
8. A syringe as recited in claim 4 wherein said closure seat further
comprises a spacer which is disposed below a bottom surface of said
closure seat and surrounded said pushing stud of said pusher member.
9. A syringe as recited in claim 5 wherein said closure seat further
comprises a spacer which is disposed below a bottom surface of said
closure seat and surrounded said pushing stud of said pusher member.
10. A syringe as recited in claim 6 wherein an air layer is defined
between said bottom surface of said closure seat and said spacer
and a plurality of air apertures are provided on said closure seat.
11. A syringe as recited in claim 7 wherein an air layer is defined
between said bottom surface of said closure seat and said spacer
and a plurality of air apertures are provided on said closure seat.
12. A syringe as recited in claim 8 wherein an air layer is defined
between said bottom surface of said closure seat and said spacer
and a plurality of air apertures are provided on said closure seat.
13. A syringe as recited in claim 9 wherein an air layer is defined
between said bottom surface of said closure seat and said spacer
and a plurality of air apertures are provided on said closure seat.
14. A syringe as recited in claim 10 wherein said spacer is integrally
extended downwardly from a bottom end of said sea ling member to
form a U-shaped body.
15. A syringe as recited in claim 11 wherein said spacer is integrally
extended downwardly from a bottom end of said sealing member to
form a U-shaped body.
16. A syringe as recited in claim 12 wherein said spacer is integrally
extended downwardly from a bottom end of said sealing member to
form a U-shaped body.
17. A syringe as recited in claim 13 wherein said spacer is integrally
extended downwardly from a bottom end of said sealing member to
form a U-shaped body.
18. A syringe as recited in claim 6 wherein said spacer comprises
a deformable washer member and a rigid pusher ring integrally attached
to a bottom surface of said washer member which is made of foaming
material that is capable of reducing thickness under axial compression,
said spacer having a thickness equal to a length of said pushing
stud so as to positioned around the pushing stud by attaching a
top side of said washer member to a bottom surface of said closure
seat.
19. A syringe as recited in claim 7 wherein said spacer comprises
a deformable washer member and a rigid pusher ring integrally attached
to a bottom surface of said washer member which is made of foaming
material that is capable of reducing thickness under axial compression,
said spacer having a thickness equal to a length of said pushing
stud so as to positioned around the pushing stud by attaching a
top side of said washer member to a bottom surface of said closure
seat.
20. A syringe as recited in claim 8 wherein said spacer comprises
a deformable washer member and a rigid pusher ring integrally attached
to a bottom surface of said washer member which is made of foaming
material that is capable of reducing thickness under axial compression,
said spacer having a thickness equal to a length of said pushing
stud so as to positioned around the pushing stud by attaching a
top side of said washer member to a bottom surface of said closure
seat.
21. A syringe as recited in claim 9 wherein said spacer comprises
a deformable washer member and a rigid pusher ring integrally attached
to a bottom surface of said washer member which is made of foaming
material that is capable of reducing thickness under axial compression,
said spacer having a thickness equal to a length of said pushing
stud so as to positioned around the pushing stud by attaching a
top side of said washer member to a bottom surface of said closure
seat.
Syringe needle description
BACKGROUND OF THE PRESENT INVENTION
1. Field of the Present Invention
The present invention relates to syringes, and more particularly
to a syringe with needle retraction arrangement for automatically
retracting the hollow needle into a hollow plunger after use so
as to prevent the used needle from contacting with anybody.
2. Description of the Related Arts
It is well known that the needles of syringes are frequently intended
for disposal after single use and rendered inoperative to prevent
accidental injury or re-use with the substantial risk of cross-contamination.
U.S. Pat. Nos. 4650468 and 4804370 each suggests a kind of
medical syringe that enables its used needle being retracted inside
the barrel by re-pulling out the plunger. It is unpractical because
the user must apply a pulling force to re-pulling out the plunger
that may cause unreasonable danger to the user.
U.S. Pat. No. 4695274 discloses an improved kind of medical syringe
which further includes a spring inside the barrel. The spring is
arranged for automatically re-pulling out the plunger so as to retract
the needle inside the barrel. However, the operation becomes much
more difficult and troublesome because extra efforts must be applied
to retain the needle's working position, i.e. extending out of the
barrel.
U.S. Pat. No. 5084018 teaches a safety syringe having a sliding
base with a hole in a barrel to hold a locking up a fix a needle
cannula, in which the hole has a flange at the bottom to prevent
downward sliding of the locking tip, the barrel being provided with
a plurality of ventilation holes at the front end and a limiting
flange at its inner wall to prevent from downward sliding of the
sliding base so that the locking tip is positioned for injection,
and a spring disposed at the locking tip between an end of the barrel
and a needle extender so that when a hollow plunger with a cork
at the top is pushed axially to the foremost position, the sliding
base is forced to displace forwardly, and consequently the locking
tip is forced to keep close contact with the extender and displace
in an opposite direction. This kind of safety syringe substantially
enables the used needle to be retracted inside the hollow plunger
so that no re-pulling operation of the plunger is required. Moreover,
a further push of the plunger is required to trigger the retraction
of the needle. However, it also contains the following unsolved
drawbacks:
(a) Both the sliding base, locking tip and the cork are simply
engaged in position by means of limiting flange structure. Such
engagement requires high manufacture accuracy to avoid unwanted
displacement of the sliding base, the locking tip or the cork during
the pushing operation of the plunger for injecting the medical liquid
in the barrel. If the sliding base, the locking tip or the cork
is not perfectly engaged in position, unwanted disengagement would
be resulted during the injection operation that may cause unexpected
injury to the patient. In order to ensure all flange engagements,
very good quality control is expected and thus the manufacture cost
of the 018' patent is relatively higher than usual. Furthermore,
since different concentration of the medical liquid may contribute
different compressing pressure against the sliding base, locking
tip and the cork during the injection operation as mentioned above,
a particularly kind of syringe of the 018' patent may only be applied
to designated kinds of medical liquid.
(b) The retraction of the needle relies on the inwardly push of
the sliding base towards the front end of the barrel, so that a
space must be normally retained between the front end of the barrel
and the sliding base to receive the sliding base during the retraction
operation of the needle. Therefore, a plurality of ventilation holes
must be provided at the front end of the barrel for air outlet.
It is well known that, during medical injection, air must be absolutely
prevented from injecting into a human body. Although high quality
of airtight sealing can be provided between the barrel and the sliding
base, it is still unreasonable to expose the patient to any kind
of such risk.
U.S. Pat. No. 5782804 suggests a fluid handling device having
a needle retraction assembly which brings about the retraction of
a hollow needle after use, wherein a movable sleeve member is provided
to substitute the sliding base in the above mentioned 018' patent,
and an annular space communicating with outside is formed so that
the air space between the sliding base and the front end of the
barrel and the air ventilation holes provided on the front end of
the barrel as suggested in the 018' patent are eliminated. However,
this 804' patent also creates the following new drawbacks at the
same time.
(a) As shown in FIGS. 6 and 9 of the 804' patent, some medical
liquid will be left in the space formed between the end wall of
the piston and the front end of the body portion when the piston
is fully pushed before the needle is retracted. In other words,
the medicine being actually injected is less than the required dose
of medicine.
(b) The engagement between the sleeve member 36 and the needle
end portion 18 must be firmer than the engagement between the sleeve
member 36 and the annular wall portion 32 of the barrel, so that
when the sleeve member 36 is downwardly pressed by the piston 6
the needle end portion 18 will downwardly move with the sleeve member
36 and compress the spring 28 as shown in FIG. 9. However, it is
unreasonable that when the sleeve member 36 is pushed to the bottom
position as shown in FIG. 10 the spring 28 will push up the needle
and the needle end portion 18 to retract upwardly into the hollow
piston 6 without driving the sleeve member 36 upwards at the same
time.
SUMMARY OF THE PRESENT INVENTION
The main object of the present invention is to provide a syringe
with needle retraction arrangement for automatically retracting
the hollow needle into a hollow plunger after use so as to prevent
the used needle from contacting with anybody.
Another object of the present invention is to provide a syringe
with needle retraction arrangement which is easy to assembly and
has a relatively low manufacturing cost.
Another object of the present invention is to provide a syringe
with needle retraction arrangement, wherein no air ventilation holes
or air space is required in the structure.
In order to accomplish the above objects, the present invention
provides a syringe with needle retraction arrangement, which comprises:
a hollow barrel having an open end portion, a needle mounting portion,
and a tubular needle hub extending from the needle mounting portion
to provide a needle passageway therethrough and an end shoulder
radically extended inwardly from a free end of the needle mounting
portion,
a hollow needle having a tissue penetrating end and a tip end thereof
affixed with a cylindrical tip head which has a shallow ring groove
provided thereon, wherein the tip head of the hollow needle is disposed
in the needle mounting portion with the tissue penetrating end penetrating
through the needle passageway,
a compression spring surrounding the hollow needle and having two
ends pressing against the end shoulder of the needle hub and the
tip head of the hollow needle respectively,
an O-ring removably resting around the ring groove of the tip head,
a mounting seat, which is integrally affixed within the needle
mounting portion, having an O-ring passage coaxially aligned with
the needle passageway of the needle hub, a top end portion of the
O-ring passage reducing diameter to form a stopper shoulder against
which the O-ring abuts, wherein a circular gap is formed between
the ring groove of the tip head of the hollow needle and an annular
wall of the O-ring passage, the circular gap having a width smaller
than a diameter of the O-ring so as to compress the O-ring between
the stopper shoulder and the ring groove and to securely mount the
tip head in the O-ring passage, and
a hollow plunger adapted to travel through the hollow barrel, the
hollow plunger having an outer close end and an inner end inserted
in the hollow barrel through the open end portion, a closure seat
being connected to the inner end of the hollow plunger so as to
define a receiving cavity inside the hollow plunger, the closure
seat having an entrance aperture positioned above the O-ring passage
of the mounting seat, the entrance aperture being covered by a pusher
member which is circumferentially connected with the entrance aperture
in such a manner that the pusher member is detached to open the
entrance aperture when a predetermined pound of urging force is
applied to the pusher member.
Therefore, when the closure seat of hollow plunger is intentionally
pushed towards the mounting seat, the pusher member presses the
tip head as well as the O-ring thereon to slide towards the needle
hub and further compress the compression spring to store a resilient
force. The present invention is arranged in such a manner that when
the O-ring is pressed to travel through of the O-ring passage, the
resilient force of the compression spring will be increased to a
force larger than the predetermined pound of urging force. At this
moment, the engagement of the O-ring between the ring groove of
the tip head and the annular wall of the O-ring passage is released,
wherein the resilient force stored in the compression spring will
upwardly push the tip head of the hollow needle to press against
the pusher member and breaks its connection with the closure seat
to open the entrance aperture, so that the hollow needle, the pusher
member and the compression spring will all be retracted into the
receiving cavity of the hollow plunger automatically.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a syringe with needle
retraction mechanism according to preferred embodiment of the present
invention.
FIG. 2 is a sectional view of the syringe, while it is empty, according
to the above preferred embodiment of the present invention.
FIG. 3 is a partial sectional view of the syringe, while it is
filled with medicine, according to the above preferred embodiment
of the present invention.
FIG. 4 is a partial sectional view of the syringe according to
the above preferred embodiment of the present invention, illustrating
how the pusher member pressing against the tip head of the needle.
FIG. 5 is a partial sectional view of the syringe, while its needle
is retracted inside the plunger, according to the above preferred
embodiment of the present invention.
FIG. 6 is a partial sectional view of a syringe according to an
alternative mode of the above referred embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 to 5 a syringe 10 with needle retraction
arrangement according to a preferred embodiment of the present invention
is illustrated, which comprises a hollow barrel 20 a hollow needle
30 a compression spring 40 an O-ring 50 a mounting seat 60 and
a hollow plunger 70.
The hollow barrel 20 has an open end portion 21 a needle mounting
portion 22 and a tubular needle hub 23 extending from the needle
mounting portion 22 to provide a needle passageway 24 therethrough
and an end shoulder 25 radically extended inwardly from a free end
221 of the needle mounting portion 22 as shown in FIGS. 1 and 2.
The hollow needle 30 has a tissue penetrating end 301 and a tip
end 302 thereof affixed with a cylindrical tip head 31 which has
a shallow ring groove 32 provided thereon for the O-ring 50 removably
resting therearound, wherein the tip head 31 of the hollow needle
30 is disposed in the needle mounting portion 22 with the tissue
penetrating end 31 penetrating through the needle passageway 24.
The compression spring 40 which is arranged surrounding the hollow
needle 30 has two ends 41 42 pressing against the end shoulder
25 of the needle hub 24 and the tip head 31 of the hollow needle
30 respectively, as shown in FIGS. 3 and 4.
The mounting seat 60 as shown in FIGS. 3 and 4 which is integrally
affixed within the needle mounting portion 22 has an O-ring passage
61 coaxially aligned with the needle hub 23 a top end portion 611
of the O-ring passage 61 reducing diameter to define a stopper shoulder
62 against which the O-ring 50 abuts, wherein a circular gap 63
is formed between the ring groove 32 of the tip head 31 of the hollow
needle 30 and an annular wall 612 of the O-ring passage 61 the
circular gap 63 having a width smaller than a diameter of the O-ring
50 so as to compress the O-ring 50 between the stopper shoulder
62 and the ring groove 32 and to securely mount the tip head 31
in the O-ring passage 61.
The hollow plunger 70 which is adapted to coaxially travel through
the hollow barrel 20 has an outer close end 71 and an inner end
72. The outer close end 71 has a plurality of air holes 711 provided
thereon, as shown in FIGS. 1 and 2. The inner end 72 is inserted
in the hollow barrel 20 through the open end portion 21 a closure
seat 73 being connected to the inner end 72 of the hollow plunger
70 so as to define a receiving cavity 700 inside the hollow plunger
70.
As shown in FIGS. 3 4 and 5 the closure seat 73 has an entrance
aperture 731 positioned above the O-ring passage 61 of the mounting
seat 60 and a plurality of air apertures 732 provided around the
entrance aperture 731. The entrance aperture 731 is covered by a
pusher member 74 which is circumferentially connected with the entrance
aperture 731 through a circular thin connecting rib 741 in such
a manner that, the thin pusher member 74 is detached to open the
entrance aperture 731 when a predetermined pound of urging force
is applied to the pusher member 74 and breaks the connecting rib
741.
Therefore, when the closure seat 73 of hollow plunger 70 is intentionally
pushed towards the mounting seat 60 the pusher member 74 presses
the tip head 31 as well as the O-ring 50 thereon to slide towards
the needle hub 23 and further compress the compression spring 40
to store a resilient force.
According to the preferred embodiment of the present invention,
the pusher member 74 further comprises a pushing stud 742 protruded
towards the mounting seat 60 and a plurality of pressing wings 743
spacedly extended from the pushing stud 742 downwardly. The pushing
stud 742 has a size adapted to enter the O-ring passage 61 and directly
apply pressing force onto the tip head 31 of the needle 30 when
the plunger 70 is inwardly pushed towards the mounting seat 60.
As shown in FIGS. 3 to 5 a sealing groove 721 is provided around
the inner end 72 for holding a ring shaped sealing member 75 thereon.
The sealing member 75 which is made of elastic material such as
rubber, fits in the clearance between an inner annular wall 201
of the barrel 20 and the sealing groove 721 so as to ensure air
tight and sealing effects of the plunger 70.
The closure seat 73 further comprises a spacer 76 disposed below
a bottom surface of the closure seat 73 and extended surrounding
the pushing stud 742 of the pusher member 74 wherein an air layer
761 is defined between the bottom surface of the closure seat and
the spacer 76.
According to the preferred embodiment of the present invention,
as shown in FIGS. 3 to 5 the spacer 76 is integrally extended downwardly
from a bottom end of the sealing member 75 to form a U-shaped body.
As shown in FIG. 3 the liquid form medicine 80 is sucked in through
the hollow needle 30 to fill between plunger 70 and the mounting
seat 60 inside the barrel 20. When the plunger 70 is pushed down
gradually, the medicine 80 is pushed to eject through the hollow
needle 30 which is penetrated into a patient's tissue. As shown
in FIG. 2 when the plunger 70 is fully pushed down until the spacer
76 is in contact with a top surface 64 of the of the mounting seat
60 all medicine is ejected and then the needle 30 can be withdrawn
from the patient's tissue. At this moment, the pressing wings 743
are inserted into the top end portion 611 of the O-ring passage
61 and in contact with O-ring 50.
After the user completely pulls out the needle 30 from the patient,
the user can immediately apply an additional force to push in the
plunger 70 that will deform the spacer 76 and compress the air layer
761 wherein the air inside the air layer 761 may escape through
the air apertures 732 into the receiving cavity 700 of the plunger
70. Therefore, the pushing stud 742 can thus be further downwardly
pressed against the tip head 31 of the needle 30 to push the tip
head 31 and compress the compression spring 40 to store a resilient
force, as shown in FIG. 4. At the same time, the pressing wings
743 will also be downwardly pressed against the O-ring 50 rested
around the ring groove 32 towards the needle hub 23.
According to the preferred embodiment of the present invention,
as shown in FIGS. 4 and 5 the engagement of tip head 31 within
the O-ring passage 61 is arranged in such a manner that, after the
O-ring 50 is pushed by the pressing wings 743 to travel through
of the O-ring passage 61 the compression spring 40 can be continuously
compressed until its resilient force is increased to a force larger
than the predetermined pound of urging force required to break the
connecting rib 741. At this moment, the O-ring is pushed out of
the O-ring passage 61 so that the engagement of the O-ring 50 between
the ring groove 32 of the tip head 31 and the annular wall 612 of
the O-ring passage 61 is released. Then, the resilient force stored
in the compression spring 40 will upwardly push the tip head 31
of the hollow needle 30 to press against the pusher member 74 until
its connecting rib 741 is broken to open the entrance aperture 731
of the closure seat 73 shown in FIG. 5 so that the hollow needle
30 the pusher member 74 and the compression spring 40 will all
be retracted into the receiving cavity 700 of the hollow plunger
70 automatically.
Referring to FIG. 6 an alternative mode of the syringe according
to the above preferred embodiment of the present invention is illustrated,
wherein the spacer 76 of the above preferred embodiment is substituted
by an alternative spacer 76' which comprises a deformable washer
member 761' and a plastic made pusher ring 762' integrally attached
to a bottom surface of the washer member 761'. The deformable washer
member 761' is made of foaming material so that it is capable of
reducing its thickness under axial compression. The spacer 76' has
a thickness equal to a length of the pushing stud 742 so as to positioned
around the pushing stud 742 by attaching a top side of the washer
member 761' to a bottom surface of the closure seat 73.
Accordingly, the syringe 10 as disclosed in the present invention
can be easily operated to retract the hollow needle 30 into a hollow
plunger 70 after use so as to prevent the used needle 30 from contacting
with anybody. Moreover, the syringe 10 is easy to assembly and has
a relatively low manufacturing cost.
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