Safety syringe

Details Safety syringe Safety syringe

2003-05-15

2004-12-07

Kennedy, Sharon (Department: 3762)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

C604S229000, C604S195000

Reexamination Certificate

active

06827704

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to syringes, and particularly to a safety syringe having a simple structure so that it can not be reused.
BACKGROUND OF THE INVENTION
With reference to
FIGS. 1
to
4
, the prior art syringe includes a syringe
10
, a seat
20
and a push rod
30
.
The syringe
10
is a round cylinder penetrated from the front end to the rear end. A stop wall
11
is radially arranged to be at an inner wall of the syringe
10
near the front end thereof. An annular first unidirectional buckling lip
13
is installed at an inner wall of the rear side of the syringe
10
.
A front end of the seat
20
is a sleeve
21
for connecting a needle
40
. A seat has a liquid flow channel
22
which penetrates the front and rear ends of the syringe and at an axial center thereof. A rear end of the liquid flow channel
22
is formed with an unidirectional buckling chamber
23
. An outer wall of the seat
20
is formed with an annular groove
24
with respect to the first lip
12
at a front end of the syringe
10
.
The front end of the push rod
30
has a rod head
31
. A plurality of connecting points
32
serves for connecting the push rod
30
with he rod head
31
so as to be formed as a breaking section
33
by which the rod head
31
is broken after use. The rod head
31
has a second water-stop ring
34
. A front end of the rod head
31
has a tapered buckling head
35
.
By above mentioned structure, the seat
20
and rod head
31
of the push rod
30
can enter into the syringe
10
. Then, the seat
20
can be pushed into the first lip
12
at the front end of the syringe
10
so as to be buckled to a front end of the syringe
10
. The sleeve
21
at a front end of the seat
20
protrudes from the front end of the syringe
10
. Thereby, needle
40
can be screwed into the syringe
10
(referring to FIG.
1
). When the push rod
30
is pushed to a foremost end, the buckling head
35
at the front end of the rod head
31
can be pressed into the unidirectional buckling chamber
23
at a rear end of the seat
20
(referring to FIG.
2
). Next, the push rod
30
is pulled backwards and at the same time, the seat
20
is retracted so that the needle
40
can be placed into the syringe
10
(referring to FIG.
3
). Further, the needle
40
is retracted to be stored in the syringe
10
. Then the rod head
31
is broken to separate from the push rod
30
(referring to FIG.
4
). Thereby, the syringe
10
can be not reused. Thereby, the object of safety is achieved.
However when the push rod
30
is pushed to the foremost end (referring to FIG.
5
), the buckling head
35
at the foremost is plugged into the unidirectional buckling chamber
23
at the rear end of the seat
20
so that the seat
30
is firmly secured to the push rod
30
. When the push rod
30
is pulled backwards, the seat
30
can be pulled out at the same time. Thereby, the needle
40
is stored in the syringe
10
. Thus, the buckling head
35
at the front end of the push rod
30
is easily plugged into the unidirectional buckling chamber
23
at the rear end of the seat
20
. To cause that the buckling head
35
will not separate from the unidirectional buckling chamber
23
and can drive the seat
20
to move backwards when the push rod
30
moves backwards. A high precision is necessary so that it is difficult to make, maintain and prepare a mold. As a result, the cost is increased Moreover, to control the precision of the buckling head
35
and the unidirectional buckling chamber
23
is difficult so that the quality can not be well controlled.
Further, a front end of the liquid flow channel
22
of the seat
20
has a space which would accumulates drugs therein so that when the push rod
30
is pushed to the foremost end, part of the drug will flow into the liquid flow channel
22
. The amount of the drug is over the international standard, 0.075 ml.
SUMMARY OF THE INVENTION
Accordingly, the primary object of the present invention is to provide a safety syringe, which can improve prior art defects as mentioned above.
To achieve above objects, the present invention provides a safety syringe, wherein plurality of axial slits are formed in the outer wall of the unidirectional buckling chamber of the seat. An inner wall of the unidirectional buckling chamber has a second unidirectional buckling lip. A buckling head at a front end of the rod head of the push rod is installed with a unidirectional buckling lip; the third unidirectional buckling lip is installed with a plurality of slits so that the third unidirectional buckling lip is elastic. Thereby, by the axial slits of the unidirectional buckling chamber and the slits of the third unidirectional buckling lip, when the push rod is pushed to a foremost end, the buckling head at the front end of the rod head is pushed into the unidirectional buckling chamber at the rear end of the rod head of the push rod. The buckling head at the front end of the rod head of the push rod is extended with an axial strip. When the push rod is pushed to a foremost end, the axial strip is inserted into the liquid flow channel of the seat, the liquid in the liquid flow channel is pushed out so as to reduce the residue of the liquid so as to match the international standard.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.


REFERENCES:
patent: 5308329 (1994-05-01), Mazur et al.
patent: 5401246 (1995-03-01), Mazur et al.
patent: 5578015 (1996-11-01), Robb
patent: 6458105 (2002-10-01), Rippstein et al.
patent: 6761707 (2004-07-01), Huang et al.
patent: 2003/0212371 (2003-11-01), Smith et al.

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