A single chamber disposable syringe containing a medicament includes
a valve member positioned in the variable volume chamber adjacent
to the medicament outlet for selectively communicating the variable
volume chamber with the medicament outlet.
What is claimed is:
1. A single chamber disposable syringe containing a medicament
comprises: a main body having a sidewall, an upper base having a
medicament outlet and a lower base having an opening which receives
a movable plunger, said sidewall, upper base and plunger together
define a variable volume chamber; and a valve member positioned
in said variable volume chamber adjacent to said upper base for
selectively communicating said variable volume chamber with said
medicament outlet when said plunger is moved alternately away from
and toward said upper base, wherein said valve member comprises
(1) a hollow peripheral valve portion sealingly located on the sidewall
of the chamber and abutting said upper base and (2) a rigid inner
valve portion movably received in the hollow peripheral valve portion
and moveable between a first position for establishing communication
between the variable volume chamber and said medicament outlet and
a second position for prohibiting communication between said variable
volume chamber and said medicament outlet, wherein movement of the
plunger in a first direction away from said upper base moves the
inner rigid valve portion to the first position for communicating
the variable volume chamber with said medicament outlet and movement
of the plunger in a second direction tranfers the medicament from
the variable volume chamber to said medicament outlet until the
plunger abuts the inner rigid valve portion and moves same to the
2. A syringe according to claim 1 wherein the hollow valve portion
is cup-shaped and has a sidewall portion extending from a base portion,
the base portion includes a control conduit.
3. A syringe according to claim 2 wherein the inner rigid valve
portion has a body portion sealingly received on the sidewall portion
on the hollow valve portion and a projecting portion received in
the central conduit of the hollow valve portion when in the second
4. A syringe according to claim 1 wherein the hollow peripheral
valve portion has a plurality of flanges for sealing on the sidewall
of the chamber.
5. A syringe according to claim 4 wherein the body portion has
a plurality of flanges for sealing on the sidewall portion of the
hollow peripheral valve portion.
BACKGROUND OF THE INVENTION
The present invention is a single-chamber syringe having an internal
valve-type closure actuatable by displacement of the plunger for
administration of liquid products, especially medicinal products
(medicament), which require the act of injection for administration
thereof to a patient. More specifically, the present invention is
drawn to a syringe belonging to the group which can be marketed
with the product to be injected contained therein and are therefore
known as disposable "prefilled syringes", and are provided
with the medicinal product contained therein to ensure that the
user does not come into contact with the product.
Numerous syringes are known which have been produced for the same
purpose as stated above. All of them are formed of a cylindrical
and hollow main body within which is accommodated the medicinal
product which is to be administered and within which a coaxially
arranged plunger moves. In all these cases, the lower base of the
main cylindrical body is opened and allows the displacement of the
plunger. In general, they include a flange which projects to the
outside and is used as a support point for the user to push or pull
on the plunger. At the other end, the opposite base of the main
cylindrical body defines a hollow and coaxial tip which is frustoconical
and acts as a connecting or coupling for the attachment of the injection
needle. Such a device is shown in U.S. Pat. No. 5785683.
The novelty which distinguishes this embodiment lies in the fact
that the syringe includes a very special valve-type closure for
keeping the liquid content isolated, the closure being designed
to open or close, allowing or preventing the passage of fluid to
the injection needle by displacement of the plunger.
Co-pending application Ser. No. 09/344974 relates to a syringe
having a double internal chamber, which is suitable for bringing
about the mixing of two separate components by displacement of the
plunger. The valve used is internal, so that it requires no modification
to the main cylindrical body of the syringe or even the incorporation
of special plugs to close its open base, permitting the displacement
of the plunger without undesirable losses of content occurring.
The valve which is accommodated within the main cylindrical body,
divides the latter into two internal chambers of variable volume,
so that the active head of the plunger simultaneously acts as the
face closing the distal chamber.
On the other hand, in the case of the present application, the
valve is not used to form two internal chambers but is designed
to act as an upper hermetic closing for a single isolated chamber
which contains the product.
In the case of the '974 application, the novel internal valve uses
two elastomeric portions which act by cooperating with one another,
so that they mix the originally isolated components, when the plunger
moves in a direction opposite to the injection action and allows
the mixture to escape toward the injection needle when the plunger
is displaced, performing the injection action.
SUMMARY OF THE INVENTION
The internal valve-type plug incorporated in the single-chamber
syringe according to the present invention, is characterized in
that it is arranged adjacent to the connecting cone of the syringe
bearing on the internal face of its upper base, so that the projecting
portion that it possesses, in this case, blocks communication with
the injection needle, while the lower base of the internal body
of the plug is the upper base of the internal chamber of the syringe
which accommodates the liquid.
In this manner, when the user displaces the plunger, by pulling
in the direction opposite to the injection direction, the internal
body moves away from the periphery, opening communication to the
needle. Once this communication has come about, the conventional
method is followed of displacing said plunger in the injection action
whereby the liquid flows toward the needle and, through the needle,
to the outside, passing through the valve assembly.
An advantage over the known art lies in the fact that it is no
longer necessary to include a plug in the connecting cone within
which communication with the injection needle is established, since
the valve plug itself produces hermetic sealing from the interior
of the syringe.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to facilitate understanding of the design and functional
features of the inventive single-chamber syringe, a description
is given below of a preferred embodiment, which is illustrated schematically
FIG. 1 is a sectional view in a longitudinal vertical plane which
shows a needle of the prefilled type having a valve means as protected
by the present patent and arranged in the closed position;
FIG. 2 is a sectional view similar to the previous figure but,
in this case, with the same valve means in the position adopted
when the user displaces the plunger in the direction opposite to
the injection direction; and
FIG. 3 is the same view in longitudinal section, but in this case
showing the arrangement of the elements taking part in the course
of the injection action.
It should be made clear that, in all the figures, the same reference
numerals correspond to the same or equivalent constituent parts
or elements of the assembly, in accordance with the example selected
for the present explanation of the single-chamber syringe forming
the subject of the invention.
As may be appreciated from the drawings, the single-chamber syringe
having an internal valve-type closure to which the present patent
relates belongs to the type of those comprising a main body (1),
which is a circular cylinder of straight axis, having its lower
base (2) completely open, in which is also included the annular
flange (3) which the user uses as a support for actuating the plunger
The upper base (4) includes the coaxial hollow injection tip (5),
where an internal tube (6) is defined through which the liquid flows
toward the injection needle (9) protected by the sheath (8) which
is retained removably when inserted, with a close fit, into the
annular cavity defined by the face (7).
As is apparent from these three figures, the plunger (10) possesses
an active head (11) which acts as a sliding closure plug to prevent
the escape of liquid from the interior of the main cylindrical body
(1). This is an elastomeric element whose annular flange (12) bears
with friction on the cylindrical surface of the body (1), providing
a seal to said closure to ensure that no undesirable leaks of liquid
take place without obstructing the normal displacement of the plunger.
As can be seen in FIG. 1 the internal valve assembly used by the
syringe according to the invention comprises a peripheral body (13)
which acts to cooperate with an internal body (14), which assembly
is arranged adjacent to the upper base of the main body and within
the latter, so that a single internal chamber (16) is defined between
this valve assembly and the active head (11) of the plunger and
is designed to accommodate and keep isolated the liquid product
The special design of this valve assembly enables the displacements
of said plunger to bring about the opening and closure of the passage
to the needle. This is done by means of the suction and pressure
exerted by the liquid content itself when said displacements of
the plunger take place.
From a study of the three representative figures, it is possible
to understand the special design of this valve assembly and, in
particular, how it acts in a single-chamber syringe.
The internal valve body (14) possesses a special projecting central
section (21) which, being arranged coaxially with said tube (6)
communicating with the injection needle (9), acts as an upper closing
plug ensuring the proper isolation of the latter from the chamber
Since this is a valve means where relative and combined movements
take place, both the body (13) and the body (14) and its projecting
section (21) possess respective annular flanges indicated by references
(17 18 19 20 23 24 and 25), which bear upon corresponding internal
cylindrical surfaces upon which they move.
FIG. 1 shows the arrangement of all the elements and parts that
intervene when the syringe is in the position of rest, containing
the liquid medicinal product in said chamber (16). The seal is absolutely
leaktight and secure both toward the lower base and toward the upper
base of said syringe.
From a study of FIG. 2 it will be understood that when the plunger
(10) is moved in the direction opposite to that of injection, a
vacuum is created in said chamber (16) which produces the relative
movement of the body (14) relative to the peripheral body (13),
so that an upper communication tube (22) is opened with said tube
(6) which faces the injection needle.
As is apparent from the three figures, this tube (22) is no more
than an opening or orifice made in the upper base of the peripheral
body (13), coaxial with the axis of symmetry of the syringe and
therefore aligned with said tube (6) of the tip (5) through which
the liquid circulates.
From a study of FIG. 3 it will be understood that when said plunger
(10) moves in the injection action, the fluid advances in the direction
opposite to that shown in the previous figure, passing first through
the transfer cavities (26) and then, through said tube (22) progressing
toward the needle (9).
When the active head of said plunger (10) enters into contact with
the body (14), it can continue advancing and therefore dislodging
liquid toward the tube (22) until the projecting and coaxial section
(21) itself prevents it.
It is to be understood that the invention is not limited to the
illustrations described and shown herein, which are deemed to be
merely illustrative of the best modes of carrying out the invention,
and which are susceptible of modification of form, size, arrangement
of parts and details of operation. The invention rather is intended
to encompass all such modifications which are within its spirit
and scope as defined by the claims.