Syringe needle abstract
A needle holder used in a safety hypodermic syringe, including
a hollow cylindrical body having a rear coupling structure adapted
to receive a front retaining tip of the plunger of the safety hypodermic
syringe with which the needle holder is used, wherein the needle
holder has at least one movable unit and at least one engagement
unit respectively connected to the hollow cylindrical body, the
at least one movable unit being alternatively shifted between an
extended-output status where the at least one movable unit is respectively
disengaged from the at least one engagement unit, and an inwardly
squeezed status where the at least one movable unit is respectively
forced by an external force into engagement with the at least one
engagement unit.
Syringe needle claims
What the invention claimed is:
1. A needle holder used in a safety hypodermic syringe, comprising
a hollow cylindrical body, said hollow cylindrical body comprising
a front hub adapted to hold a needle cannula, and a rear coupling
structure adapted to receive a front retaining tip of the plunger
of the safety hypodermic syringe with which the needle holder is
used, wherein said needle holder comprises at least one movable
unit and at least one engagement unit respectively connected to
said hollow cylindrical body, said at least one movable unit being
alternatively shifted between an extended-output status where said
at least one movable unit is disengaged from said at least one engagement
unit, and an inwardly squeezed status where said at least one movable
unit is respectively forced by an external force into engagement
with said at least one engagement unit.
2. The needle holder of claim 1 wherein said at least one movable
unit is respectively disposed at an outer side relative to said
at least one engagement unit when shifted to said extended-out status.
3. The needle holder of claim 1 wherein said at least one movable
unit each has a front part connected to said hollow cylindrical
body so that a rear part of each of said at least one movable unit
is movable relative to the respective front part.
4. The needle holder of claim 3 wherein the front part of each
of said at least one movable unit has a connecting strip connected
to said hollow cylindrical body.
5. The needle holder of claim 3 wherein the rear part of each of
said at least one movable unit comprises a bottom hooked portion
adapted for engagement with said at least one engagement unit.
6. The needle holder of claim 1 wherein said at least one movable
unit includes a plurality of movable units arranged in a symmetrical
relationship.
7. The needle holder of claim 1 wherein the rear coupling structure
of said hollow cylindrical body is peripherally mounted with an
O-ring.
8. The needle holder of claim 1 wherein said at least one movable
unit each comprises a protruding block.
9. A safety hypodermic syringe comprising a barrel having a front
end and a rear end, a plunger moved in said barrel between the front
end and rear end of said barrel, a needle holder mounted in the
front end of said barrel, and a needle cannula fastened to said
needle holder, said needle holder comprising a hollow cylindrical
body, said hollow cylindrical body comprising a front hub, which
holds said needle cannula, and a rear coupling structure adapted
to receive a front end of said plunger, wherein said needle holder
comprises at least one movable unit and at least one engagement
unit respectively connected to said hollow cylindrical body, said
at least one movable unit being alternatively shifted between an
extended-output status where said at least one movable unit are
disengaged from said at least one engagement unit, and an inwardly
squeezed status where said at least one movable unit are respectively
forced by external force into engagement with said at least one
engagement unit; said barrel comprises an inside stop flange, which
supports said needle holder in the front end of said barrel when
said at least one movable unit is respectively shifted to said extended-out
status, and an inside engagement wall portion, which secures said
needle holder to said inside stop flange when said at least one
movable unit is respectively shifted to said extended-out status
and forces said at least one movable unit inwardly from said extended-out
status to said inwardly squeezed status when said plunger is moved
to the front end of said barrel.
10. The safety hypodermic syringe of claim 9 wherein said at least
one movable unit each comprises a protruding block, which is stopped
in between said inside stop flange and said inside engagement wall
portion when at said extended-out status.
Syringe needle description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a safety hypodermic syringe, and
more particularly to such a safety hypodermic syringe, which enables
the needle assembly to be received inside the barrel after its service.
2. Description of the Prior Art:
After the service of a safety hypodermic syringe, as shown in FIG.
1 the user (nurse or doctor) immediately pushes the plunger 92
forwards into engagement with the needle holder 10 and then pulls
the plunger 92 backwards to receive the needle holder 10 and the
needle cannula 91 inside the barrel 95.Taiwan Patent Publication
#356013 discloses a similar design. However, this design of safety
syringe has drawbacks. In order to let the user pull the plunger
backwards with less effort after the service of the safety hypodermic
syringe, the engagement power (normally friction force) between
the needle holder and the inside wall of the front end of the barrel
must be limited to a low level, however this design may cause the
needle holder and the needle cannula to fall from position in direction
toward the plunger. On the contrary, the user must employ much backward
pressure to the plunger to pull the needle holder and the needle
cannula back to the inside of the barrel if the engagement power
between the needle holder and the inside wall of the front end of
the barrel is relatively increased. Further, the production of the
aforesaid safety hypodermic syringe requires high-precision fabrication
equipment.
SUMMARY OF THE INVENTION
The invention has been accomplished under the circumstances in
view. It is the main object of the present invention to provide
a safety hypodermic syringe and a needle holder for the safety hypodermic
syringe, wherein the needle holder can be shifted between an extended-out
status and an inwardly squeezed status, so that the needle holder
is shifted to the extended-out status and positively secured to
the inside wall of the front end of the barrel of the safety hypodermic
syringe during the use of the hypodermic syringe, or shifted from
the extended-out status to the inwardly squeezed status for enabling
g the needle holder and the needle cannula to be smoothly pulled
with the plunger into the inside of the barrel after the service
of the safety hypodermic syringe. According to one aspect of the
present invention, the needle holder comprises a hollow cylindrical
body having a rear coupling structure adapted to receive a front
retaining tip of the plunger of the safety hypodermic syringe with
which the needle holder is used, wherein the needle holder has at
least one movable unit and at least one engagement unit respectively
connected to the hollow cylindrical body, the at least one movable
unit being alternatively shifted between an extended-output status
where the at least one movable unit is respectively disengaged from
the at least one engagement unit, and an inwardly squeezed status
where the at least one movable unit is respectively forced by an
external force into engagement with the at least one engagement
unit. According to another aspect of the present invention, the
barrel comprises an inside stop flange and an inside engagement
wall portion disposed inside the inside end thereof and adapted
to hold the needle holder positively in the front end of the barrel
when the needle holder is shifted to the extended-out status. When
pushing the plunger forwards, the at least one movable unit of the
needle holder is respectively shifted from the extended-out status
to the inwardly squeezed status by the inside engagement wall portion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view in section of the present invention before
the service of the safety hypodermic syringe.
FIG. 2 is a cutaway view of a needle holder for a safety hypodermic
syringe according to the present invention.
FIG. 3 is a side view in section of the needle holder shown in
FIG. 2.
FIG. 4 is a sectional view of the present invention, showing the
needle holder installed in the front end of the barrel.
FIG. 5 is another sectional view of the present invention, showing
the extended-out status of the needle holder.
FIG. 6 is still another sectional view of the present invention,
showing the inwardly squeezed status of the needle holder.
FIG. 7 is still another sectional view of the present invention,
showing the plunger pulled backwards, the needle holder and the
needle cannula received inside the barrel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. from 1 through 6 a safety hypodermic syringe
90 is shown comprised of a needle cannula 91 a needle holder 10
a barrel 95 and a plunger 92 with a stopper 92. When pushing the
plunger 92 forwards, the front retaining tip 922 of the plunger
92 is forced into engagement with the rear engagement portion 131
of the needle holder 10 so that the needle holder 10 and the needle
cannula 91 are pulled backwards into the inside of the barrel 95
when pulling the plunger 92 backwards.
Referring to FIGS. from 2 through 6 again, the scope of the invention
is the design of the movable unit 20 and engagement unit 30 of the
needle holder 10. According to a first embodiment of the present
invention, the needle holder 10 comprises a hollow cylindrical body
11. The hollow cylindrical body 11 comprises a front hub 12 defining
a longitudinal center needle hole 121 adapted to hold the needle
cannula 91 a rear coupling structure 13 defining a receiving chamber
19 adapted to receive the front retaining tip 922 of the plunger
92. The aforesaid rear engagement portion 131 is formed integral
with the rear coupling structure 18 inside the receiving chamber
19 and adapted to hold the front retaining tip 922 of the plunger
92 in the receiving chamber 19. Because the rear engagement portion
131 and the front retaining tip 922 are not the main features of
the design of the present invention, they are not described in detail.
The engagement unit 30 is connected to the hollow cylindrical body
11 between the needle hub 12 and the rear coupling structure 13.
The movable unit 20 comprises a front connecting strip 21 connected
to a supporting unit 14 of the hollow cylindrical body 11 a bottom
hooked portion 22 and two protruding blocks 23 sloping downwardly
outwards at two opposite sides. Further, a space 141 is provided
between the supporting unit 14 and the front hub 12 for enabling
the lower part of the movable unit 20 to be moved inwards.
Referring to FIG. 4 again, before the use of the safety hypodermic
syringe 90 the needle holder 10 is disposed in the front end 951
of the barrel 95. The barrel 95 comprises an inside stop flange
952 and an inside engagement wall portion 953. The protruding blocks
23 of the movable unit 20 are set in between the inside stop flange
952 and the inside engagement wall portion 953 keeping the needle
holder 10 positively retained to the front end 951 of the barrel
95. Further, an O-ring 18 is fastened to the periphery of the rear
coupling structure 13 of the hollow cylindrical body 11 to seal
the gap between the needle holder 10 and the barrel 95.
FIG. 5 illustrates the plunger 92 pushed forwards, the front retaining
tip 922 of the plunger 92 engaged with the rear engagement portion
131 of the rear coupling structure 13 of the needle holder 10. At
this stage, medicine has been completely injected into the body
of the patient. In FIGS. 4 and 5 the movable unit 20 extends out,
i.e., the movable unit 20 and the engagement unit 30 are not engaged
with each other. According to this embodiment, the movable unit
20 is disposed at an outer side relative to the engagement unit
30.
FIG. 6 shows the plunger 92 pushed forwards after removable of
the safety hypodermic syringe 90 from the body of the patient, the
movable unit 20 moved over the inside engagement portion 953 and
squeezed inwards, the bottom hooked portion 22 of the movable unit
20 forced into engagement with the engagement unit 30.
According to the present invention, the needle holder 10 comprises
at least one movable unit 20. Preferably, multiple movable units
20 are provided and arranged in a symmetrical relation.
FIG. 7 shows the plunger 92 pulled backwards, the needle holder
10 and the needle cannula 91 received inside the barrel 95. Because
the movable unit 20 is squeezed inwards, it can be moved smoothly
with the plunger 92 in the barrel 95 upon backward movement of the
plunger 92 and the inside stop flange 952 does not hinder backward
movement of the inwardly squeezed movable unit 20.
It is to be understood that the drawings are designed for purposes
of illustration only, and are not intended for use as a definition
of the limits and scope of the invention disclosed. |