Safety syringe abstract
A disposable safety syringe including a cylindrical pump body extended
by a needle integral with the body and including a plunger. The
pump body includes a distal part provided with the needle and a
proximal part with a larger diameter including the plunger; the
distal part includes a sealing part.
Safety syringe claims
What is claimed is:
1. A disposable safety syringe comprising: a cylindrical pump body
extended by a needle fastened to said body including a plunger and
a distal part fitted with said needle and a proximal part of larger
diameter including said plunger, said distal part including a valve
assembly for limiting use of the syringe to a single use, said valve
assembly comprises, a fixed member fastened to an inside wall of
the distal part and a mobile member located between said fixed member
and an outlet from the proximal part into said distal part, said
mobile member consisting of a valve connected by a compression leaf
spring having two ends, one end of the compression spring being
fastened to a base of said valve and the other end of the compression
spring being fastened to the inside wall of said distal part of
the pump body.
2. A syringe according to claim 1 wherein the fixed member consists
of at least one abutment fastened to the inside-wall of the distal
part of the pump body.
3. A syringe according to claim 2 wherein the fixed member includes
at least two abutments regularly distributed on a common circle
and fastened to the inside wall of the distal part.
4. A syringe according to claim 3 wherein the valve assembly is
of cylindrical-conical shape, a conical part bing directed towards
the proximal part of the pump body and a cylindrical part including
fins disposed at its periphery.
Safety syringe description
This is a nationalization of PCT/FR00/00951 filed Apr. 13 2000
and published in French.
FIELD OF THE INVENTION
The present invention relates to a disposable so-called safety
syringe.
BACKGROUND OF THE INVENTION
Disposable syringes that must be discarded after use have been
developed to prevent contamination: such syringes generally includes
a pump body attached to the needle protected by a sheath before
use. However, it has been realized that it is possible to refill
these syringes and therefore to reuse them, whence serious risks
of contamination.
One example of a disposable hypodermic syringe is described in
U.S. Pat. No. 5045064. The syringe described includes valve means
consisting of a stud mobile along a threaded shaft, a diaphragm
between the stud and the needle. During an injection, the liquid
to be injected, pushed by the plunger, entrains the stud by rotation
along the diaphragm which traps it but allows the liquid to pass
through it.
The syringe can therefore be used again if the stud does not cooperate
with the diaphragm.
SUMMARY OF THE INVENTION
So, one aim of the present invention is to provide a disposable
so-called safety syringe that cannot be refilled after it is first
used.
Another object of the invention is to provide a syringe of this
kind which can be manufactured easily and at lower additional cost
compared to existing disposable syringes.
The above objects, and others that will become apparent hereinafter,
are achieved by a disposable so-called safety syringe including
a cylindrical pump body which is extended by a needle fastened to
the body and which includes a plunger and a distal part fitted with
the needle and a proximal part of larger diameter including a the
plunger, the distal part including valve means, characterized in
that the valve means comprise, on the one hand, a fixed member fastened
to the inside wall of the distal part and a mobile member between
the fixed member and the outlet from the proximal part into the
distal part, the mobile member consisting of a valve connected by
a compression leaf spring one end of which is fastened to the base
of the valve and the other end of which is fastened to the inside
wall of the distal part of the pump body.
The fixed member advantageously consists of at least one abutment
fastened to the inside wall of the distal part of the pump body.
In a preferred embodiment of the invention the fixed member includes
at least two abutments regularly distributed on a common circle
and fastened to the inside wall of the distal part.
The valve is advantageously of cylindrical-conical shape, the conical
part being directed towards the proximal part of the pump body and
the cylindrical part including the propulsion means such as fins
disposed at its periphery.
BRIEF DESCRIPTION OF THE DRAWINGS
The following description, which is not limiting on the invention,
must be read in conjunction with the accompanying drawings, in which:
FIG. 1 is a plan view of a disposable so-called safety syringe
in accordance with the present invention;
FIG. 2 is a view in section taken along the line II--II in FIG.
1 before any use of the syringe; and
FIG. 3 is a view in section taken along the line II--II in FIG.
1 after filing the syringe.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As can be seen in the figures, a syringe includes a cylindrical
pump body 1 fitted with a plunger 2 and a needle 3 fastened to the
pump body 1.
The pump body 1 has a distal part 4 carrying the needle 3 and a
proximal part 5 of larger diameter containing the plunger 2; the
distal part 4 includes valve means.
The skilled person is aware that "distal" refers to any
part at the needle end and "proximal" refers to any part
at the plunger end.
The valve means comprise, on the one hand, a fixed member 6 fastened
to the inside wall of the distal part 4 and a mobile member 7 that
can move between this fixed member 6 and the outlet 8 of the proximal
part 5 into the distal part 4.
The fixed member 6 consists of at least one abutment fastened to
the inside wall of the distal part 4 of the pump body 1. In a preferred
embodiment, the fixed member 6 consists of two abutments 6a and
6b disposed symmetrically on a common circle on the inside wall
of the distal part 4.
In accordance with the present invention, the mobile member 7 consists
of a valve connected by pressure means 9 to the inside wall of the
distal part 4. The valve is of cylindrical-conical shape, the conical
part 7a being directed towards the proximal part 5 of the pump body
1 and the cylindrical part 7b including propulsion means such as
fins 10 disposed at its periphery.
The pressure means preferably consist of a leaf spring 9 one end
of which is fastened to the base of the mobile member 7 and the
other end of which is fastened to the inside wall of the distal
part 4 of the pump body 1 for example in the vicinity of the fixing
of the needle 3 therein: the leaf spring is of the compression type.
When the syringe is empty, the mobile member 7 is held in position
by the fins 10 cooperating with the abutments 6a and 6b, as shown
in FIG. 2 the leaf spring holding the mobile member 7 pressed against
the abutments. On actuating the plunger 2 to fill the syringe, the
aspirated liquid enters the needle 3 through the distal part 4 without
lifting the mobile member 7 off the abutments 6a and 6b which form
a seat, due in particular to the shape of the fins 10 so that it
is able to enter the proximal part 5 to the required level.
During injection, the liquid pushed by the plunger 2 creates a
flow that exerts on the fins 10 of the mobile member 7 a force propelling
the mobile member from the outlet of the proximal part 5 into the
distal part 4 the leaf spring 9 also contributing to this same
movement. The thrust of the plunger 2 nevertheless remains sufficiently
high to counterbalance positively the propulsion force exerted on
the mobile member 7.
When the injection is completed, the mobile member 7 is pressed
against the outlet from the distal part 4 into the proximal part
5 by the leaf spring 9 and is held pressed against it: it is therefore
impossible to aspirate a liquid and thereby reuse a syringe in accordance
with the present invention. |