Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-09-10
2002-04-16
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S225000, C604S229000
Reexamination Certificate
active
06371941
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to single-use syringes in which medicament is filled preliminarily, i.e., so-called prefilled syringes and more particularly, to a prefilled syringe which is provided with a temporary stop means for temporarily stopping a plunger rod at a predetermined position when, in use, the plunger rod is depressed forwardly.
2. Description of the Prior Art
Prior to administration of injection liquid of a two-component type prefilled syringe in which powdery medicament and pharmaceutical liquid are, respectively, contained in front and rear compartments of a tubular body, a plunger rod is stopped temporarily in a state where the pharmaceutical liquid in the rear compartment has fully flowed into the front compartment by depressing the plunger rod. When the powdery medicament is sufficiently dissolved or dispersed in the pharmaceutical liquid by shaking the tubular body in this state, the injection liquid is prepared. Subsequently, by further depressing the plunger rod, the injection liquid is administered.
A prefilled syringe shown in
FIGS. 17 and 18
is known from Japanese Utility Model Laid-Open Publication No. 7-7650 (1995). In this known prefilled syringe, a pair of bosses
61
are provided on an inner periphery of a flange
55
a
of a finger grip
55
mounted on an outer periphery of a rear end portion of a tubular body
52
, while a pair of first stopper plates
65
and a pair of second stopper plates
66
are provided between neighboring two of crossed ribs
62
of a plunger rod
60
so as to not only abut on each other through a corresponding one of the ribs
62
but be axially spaced away from each other such that the plunger rod
60
is temporarily stopped by bringing the bosses
61
and the second stopper plates
66
into contact with each other.
However, in this known prefilled syringe, after the first stopper plates
65
have come into contact with the bosses
61
by inserting the bosses
61
through recesses
64
formed on a front end flange
63
of the plunger rod
60
, the plunger rod
60
is pulled slightly rearwards and rotated so as to displace the bosses
61
to between the ribs
62
free from the first stopper plates
65
. Then, by further depressing the plunger rod
60
, the bosses
61
come into contact with the second stopper plates
66
. Subsequently, after the bosses
61
and the second stopper plates
66
have been brought out of contact with each other by rotating the plunger rod
60
until the bosses
61
are positioned between the ribs
62
free from the second stopper plates
66
, injection liquid is administered by further depressing the plunger rod
60
. Therefore, this known prefilled syringe has such drawbacks that its construction is complicated and its operation is troublesome and difficult.
Meanwhile, Japanese Patent Laid-Open Publication No. 8-229122 (1996) discloses a prefilled syringe in which a forwardly obliquely and radially outwardly extending rodlike projection
70
is formed integrally with a plunger rod
75
as shown in FIG.
19
. Even if an external force such as an impact force is applied to this prior art prefilled syringe during its storage, a front end of the rodlike projection
70
is brought into contact with a finger grip
73
so as to temporarily stop the plunger rod
75
such that inadvertent displacement of the plunger rod
75
is prevented. Consequently, such a phenomenon is eliminated that medicament filled in the prior art prefilled syringe undesirably linking from an injection needle is eliminated.
In the prior art prefilled syringe of
FIG. 19
, after the plunger rod
75
has been temporarily stopped, the rodlike projection
70
is inserted into a slot
76
of the plunger rod
75
such that a sharp edge
70
a
of a front end face of the rodlike projection
70
is brought into engagement with a recess
76
a
of the slot
76
. Then, by depressing the plunger rod
75
, injection liquid is administered. However, while the plunger rod
75
is being stopped temporarily, the front end of the rodlike projection
70
is held in contact with the finger grip
73
. Thus, when an attempt is made to push the rodlike projection
70
downwardly in this state, the front end of the rodlike projection
70
is pressed against the finger grip
73
further powerfully, so that it is difficult to insert the rodlike projection
70
into the slot
76
. As a result, in this prior art prefilled syringe, when the rodlike projection
70
is inserted into the slot
76
, the rodlike projection
70
held in contact with the finger grip
73
should be spaced away from the finger grip
73
by retracting the plunger rod
75
and then, the rodlike projection
70
is required to be inserted into the slot
76
. Therefore, this prior art prefilled syringe has such a disadvantage in that air is sucked into tubular body
71
from an injection needle upon retraction of the plunger rod
75
.
Furthermore, in this prior art prefilled syringe, since the front end of the forwardly obliquely and radially outwardly extending rodlike projection
70
is brought into contact with a rear end face of the finger grip
73
, the front end of the rodlike projection
70
is apt to slide upwardly on the rear end face of the finger grip
73
, thereby resulting in an inconvenience in that the temporary stop of the plunger rod
75
becomes unstable.
SUMMARY OF THE INVENTION
Accordingly, an essential object of the present invention is to provide, with a view toward eliminating the above described drawbacks of conventional prefilled syringes, a prefilled syringe which is simple in structure and easy in operation, which eliminates a risk that air is sucked into a tubular body from an injection needle and which is provided with a temporary stop means capable of temporarily positively stopping a plunger rod.
In order to accomplish this object of the present invention, a prefilled syringe according to the present invention comprises: a tubular body which has an open front end and an open rear end; a front assembly which is mounted on an outer periphery of a front end portion of the tubular body; a finger grip which is mounted on an outer periphery of a rear end portion of the tubular body; a front sealing member which is provided in the tubular body so as to be disposed forwardly of injection liquid; a rear sealing member which is provided in the tubular body so as to be disposed rearwards of the injection liquid; a plunger rod which is provided so as to be movable in the tubular body; a temporary stop means for temporarily stopping the plunger rod through retention of the temporary stop means by the finger grip such that the rear sealing member is temporarily stopped at a predetermined position of the tubular body; and a retention canceling means for canceling the retention of the temporary stop means by the finger grip without moving the plunger rod.
The temporary stop means may be constituted by a retainer member which is elastically formed integrally with the plunger rod so as to project rearwards obliquely relative to an axis of the plunger rod and radially outwardly from the plunger rod and is retained by the finger grip upon contact of a base portion of the retainer member with a rear end face of the finger grip, while the retention canceling means may include a hollow which is formed on the plunger rod so as to receive the retainer member.
REFERENCES:
patent: 2869541 (1959-01-01), Helmer et al.
patent: 4153056 (1979-05-01), Silver et al.
patent: 4367738 (1983-01-01), Legendre et al.
patent: 4386606 (1983-06-01), Tretinyak et al.
patent: 4711637 (1987-12-01), Leigh et al.
patent: 5181909 (1993-01-01), McFarlane
patent: 5263934 (1993-11-01), Haak
patent: 5615772 (1997-04-01), Nagannuma
patent: 35 32 622 (1987-03-01), None
patent: 0 550 767 (1993-07-01), None
patent: 0 793 973 (1997-09-01), None
patent: 2 627 087 (1989-08-01), None
patent: 1 550 308 (1979-08-01), None
patent: 7-7650 (1995-02-01), None
patent: 8-229122 (1996-09-01), None
Arai Jiichi
Kakiuti Makoto
Kato Masahiko
Nguyen Anhtuan T.
Takeda Chemical Industries Ltd.
Thompson Michael M
Wenderoth , Lind & Ponack, L.L.P.
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