Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2001-03-20
2002-08-13
Hook, James (Department: 3752)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S181000, C604S187000, C604S218000, C604S240000, C604S243000
Reexamination Certificate
active
06432082
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to syringe and, more specifically, to a safety syringe, which keeps the needle holder against vibration and prevents disconnection of the needle holder from the barrel during normal use and, enables the needle cannula with the body of the needle holder to be moved backwards with the plunger and received inside the barrel after the service of the safety syringe.
FIGS. 1 and 2
show a safety syringe according to the prior art. This structure of safety syringe comprises a barrel
10
, a needle holder
20
holding a needle cannula
21
, and a plunger
26
. The barrel comprises a plurality of inside annular flanges
11
and
12
disposed around the inside wall of the front end thereof and defining two parallel inside annular grooves
13
. The needle holder comprises a peripheral positioning flange
22
and two symmetrical rear hooks
23
, and is mounted with a seal ring
24
. The peripheral positioning flange
23
and the seal ring
24
are respectively engaged into the inside annular grooves
13
of the barrel
10
, keeping the needle holder
20
secured to the front end of the barrel
10
. The plunger
26
has a front end peripherally mounted with seal ring
25
, and a front engagement block
27
forwardly axially extended from the front end. The front engagement block
27
has a peripheral groove
28
. Before the use the safety syringe, the engagement block
27
does not touch the needle holder
20
(see FIG.
2
A). After the service of the safety syringe, the engagement block
27
is forced into engagement with the rear hooks
23
of the needle holder
20
, and then the plunger
26
is pulled backwards to carry the needle holder
20
and the needle cannula
21
backwards to the inside of the barrel
10
. This structure of safety syringe is still not satisfactory in function. The drawbacks of this structure of safety syringe are numerous and outlined hereinafter.
1. The positioning of the needle holder
20
in the front end of the barrel is achieved by means of engaging the peripheral positioning flange
22
into one inside annular groove
13
of the barrel
10
. Due to tooling technical problem. the protruding distance of the peripheral positioning flange
22
from the peripheral wall of the needle holder
20
is limited. In case an excessive forward pressure is imparted to the needle holder
20
during injection, the needle holder
20
will be forced out of the barrel
10
.
2. Because the needle holder
20
has only two rear hooks
23
hooked on the engagement block
27
at two sides, the engagement between the engagement block
27
and the needle holder
20
is unstable. and the plunger
26
may slip from the needle holder
20
when pulled backwards.
3. Because the resisting force between the barrel
10
and the needle holder
20
is strong at the initial stage when pulling the plunger
26
backwards to carry the needle holder
20
back to the inside of the barrel
10
, a rod-like tool or the like may be needed to push the needle holder
20
backwards. When forcing the needle holder
20
backwards with a tool or the like, the fingers may be injured by the needle cannula
21
accidentally.
4. When moving the plunger
26
forwards to squeeze medicine out of the barrel
10
through the needle cannula
21
into the patient's body, the engagement block
27
is automatically forced into engagement with the rear hooks
23
of the needle holder
20
, thus the safety syringe cannot be used again. In case the patient has to take two injections, a new safety syringe must be used.
SUMMARY OF THE INVENTION
The present invention has been accomplished to provide a safety syringe, which eliminates the aforesaid drawbacks. It is one object of the present invention to provide a safety syringe, which prevents vibration of the needle holder during the application of the safety syringe. It is another object of the present invention to provide a safety syringe, which enables the needle cannula with the body of the needle holder to be easily separated from the mounting unit of the needle holder so that the needle cannula and the body of the needle holder can be moved backwards with the plunger and received inside the barrel after the service of the safety syringe. According to one aspect of the present invention, the needle holder of the safety syringe has a mounting unit fixedly fastened to the front end of the barrel, a body holding a needle cannula outside the barrel, a breakable slotted connecting portion connected between the mounting unit and the body, and a rear engagement block. The plunger of the safety syringe has a front tubular retaining member adapted to engage the rear engagement block for enabling the needle cannula with the body of the needle holder to be separated from the mounting unit and moved backwards with the plunger to the inside of the barrel after the service of the safety syringe. According to another aspect of the present invention, the tubular retaining member of the plunger comprises a radially expansible front lip shaped like a tapered cylinder, the front lip having a thin bottom connecting portion connected to the retaining member. The front lip stops the tubular retaining member from engaging the rear engagement block of the needle holder unless the user gives a high forward pressure to the plunger against the rear engagement block of the needle holder. Thus, the safety syringe can be used twice for the same patient.
REFERENCES:
patent: 5000738 (1991-03-01), LaVallo et al.
patent: 5053018 (1991-10-01), Talonn et al.
patent: 5180370 (1993-01-01), Gillespie
patent: 5205824 (1993-04-01), Mazur
patent: 5401246 (1995-03-01), Mazur et al.
patent: 5403287 (1995-04-01), Talonn et al.
patent: 5980487 (1999-11-01), Jones et al.
patent: 5997511 (1999-12-01), Curie et al.
Hook James
Rosenberg , Klein & Lee
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