The present invention relates to a disposable syringe construction
including a retractable or withdrawing needle, which comprises a
cylindric body defining, at one end thereof, an end piece for the
connection of the needle, and being open, at the other end thereof,
for receiving a piston therein, provided with a sealing gasket.
The main feature of the invention is that the end piece is provided
in its inside with a cutout for coupling with abutment legs of a
hub element to which the point of the needle is connected, an outer
collar being moreover provided, which can be applied to the end
of the end piece so as to prevent the hub and related needle to
be outwardly ejected.
1. A disposable syringe construction provided with a retractable
needle held in a needle hub, comprising a cylindric body defining,
at an end portion thereof, an end piece for firmly engaging said
needle hub and being open at another end portion thereof, to receive
a piston element provided with a plunger, wherein said end piece
is provided with an inner cutout, said needle hub including resilient
extending downwardly substantially opposite abutment legs provided
with lugs engageable as said lugs are resiliently deflected toward
one another in said inner cutout of said end piece, an outer collar
being moreover provided which is engaged on said end piece to clamp
said end piece therein to prevent said needle hub and needle from
being outwardly ejected.
2. A syringe construction according to claim 1 wherein said lugs
of said abutment legs provide a 90.degree. type of connection with
said inner cutout of said end piece.
3. A syringe construction according to claim 1 wherein said piston
is provided,at an end portion thereof facing said needle with a
blind hole closed by locking collar which is removably coupled with
4. A syringe construction according to claim 1 wherein one of
said lugs is provided with a locking tooth element which can be
coupled with said locking collar the other of said lugs being adapted
to operate as a guide element for coupling said lugs in said blind
hole, by causing said abutment legs to be moved resiliently toward
5. A syringe construction according to claim 4 wherein said locking
tooth is so arranged as to cause said lug thereon said locking tooth
is formed to be tilted,as said needle is withdrawn inside said cylindric
body, to prevent said needle from being further withdrawn.
6. A syringe construction according to claim 1 wherein said piston
is provided, at an intermediate portion of a piston rod thereof,
with nothches adapted to allow an end portion of said piston to
be broken in order to prevent said syringe from being re-used.
BACKGROUND OF THE INVENTION
The present invention relates to a disposable syringe construction
provided with a retractable or withdrawable needle.
As is known, a very important problem in making disposable syringes
is that of providing a possibility of re-using said syringes and
that of preventing the needle from accidentally injuring an user
handling the needle syringe.
Prior solutions to solve the above mentioned problem usually provide
to use syringes including resilient means for causing the syringe
needle to be retracted inside the syringe.
These types of syringes, however, in addition to being very expensive,
have the drawback that they involve a modification of the conventional
use method of the syringes, since, as a puncture is performed thereby,
it is anyhow usually necessary to overcome a resilient opposing
Other prior solutions, which do not provide to use resilient means,
comprise connecting elements for coupling the needle to the syringe
body, which connecting elements, however, do not provide a safe
locking of the needle in its intended position and, moreover, being
very complex from a construction standpoint.
SUMMARY OF THE INVENTION
Accordingly, the aim of the present invention is to overcome the
above mentioned drawbacks, by providing a disposable syringe contruction,
including a retractable needle, which affords the possibility of
causing the needle to be easily withdrawn inside the syringe body,
without the need of using return springs, while also providing the
possibility of safely locking the needle in its intended use position.
Within the scope of the above mentioned aim, a main object of the
present invention is to provide such a disposable syringe construction
affording the possibility of causing the needle to be withdrawn
inside the syringe by using very simple and mechanically reliable
Another object of the present invention is to provide such a disposable
syringe construction which can be made by very simple component
elements, thereby providing great economic advantages.
Yet another object of the present invention is to provide such
a disposable syringe construction which, owing to its construction
features, is very reliable and safe in operation.
According to one aspect of the present invention, the above mentioned
aim and objects, as well as yet other objects, which will become
more apparent hereinafter, are achieved by a disposable syringe
construction, provided with a retractable needle, comprising a cylindric
body defining, at an end portion thereof, an end-piece for connecting
a needle and being open, at another end portion thereof, to receive
a piston element provided with a plunger, characterized in that
said end piece is provided with an inner cut-out for engaging with
abutment legs of a hub to which said needle is connected, an outer
collar being moreover provided, which can be applied to said end
piece, by upsetting a portion of said end-piece, so as to prevent
said hub and needle from being outwardly ejected.
BRIEF DESCRIPTION OF THE DRAWINGS
Further characteristics and advantages of the present invention
will become more apparent hereinafter from the following detailed
disclosure of a preferred, through not exclusive, embodiment of
a disposable syringe construction, provided with a retractable needle,
which is illustrated, by way of an indicative, but not limitative
example, in the accompanying drawings, where:
FIG. 1 is a schematic cross-sectional exploded view showing the
cylindric body of the syringe with the needle thereof connected
to a hub or barrel element;
FIG. 2 is a schematic top plan view of the hub element;
FIG. 3 illustrates a connection step for connecting said hub element
with the syringe needle in the end-piece of the cylindric body;
FIG. 4 illustrates the application of the collar to the syringe
FIG. 5 is a cross-sectional view illustrating a method for affixing
the collar element included in the syringe by upsetting the forming
FIG. 6 is a cross-sectional view of the syringe in a ready of use
FIG. 7 represents the syringe at the end of a puncturing operation;
FIG. 8 illustrates an operating step in which the piston element
to which the syringe needle is connected is withdrawn;
FIG. 9 is a cross-section view, on an enlarged scale, showing the
syringe needle withdrawn inside the syringe cylindric body; and
FIG. 10 is a cross-sectional view illustrating an operating step
in which the piston is broken so as to prevent the syringe from
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the number references of the above figures, the
disposable syringe construction, provided with a retractable needle,
according to the present invention, comprises a cylindric body 1
which is provided, at one end portion thereof, with an end-piece
2 to which a needle is connected, said needle being generally indicated
at the reference number 3.
Inside the cylindric body 1 a piston can be engaged, generally
indicated at the reference number 4 said piston being provided
with a sealing gasket or rubber sealing element 5.
A first main feature of the present invention is that the end-piece
2 is provided, in its inside, with a cut-out portion 10 which operates
as an engagement element for the drum portion or hub 11 of the needle
More specifically, this drum or hub portion 11 is provided, at
its inner end portion, with opposite lugs 12 and 13 which can be
resiliently contracted, and including abutment legs 14 engaging
in said cut-out 10 so as to prevent the needle from being withdrawn
inside the cylindric body 1.
Moreover, the drum or hub 11 is provided with a polygonal hole
15 in which there is force engaged, in a per se known manner, the
point 16 of the needle 3.
In order to provide a firm connection, after having introduced
the needle 3 by urging the hub so as to cause the abutment legs
14 of the hub to be engaged in the cut-out 10 an outer collar 20
is applied, which, more specifically, is applied on the end portion
of the end-piece 2 and being urged so as to upset the material,
at the end of the end-piece, to provide a narrowing region, indicated
at 21 in FIG. 5 adapted to operate as a locking element for preventing
the needle 3 from being withdrawn from the cylindric body.
As shown, the piston 4 is provided, at the end portion of the plunger
5 with a blind hole 30 including a locking collar 31 adapted
for engagement with the ends of the lugs 12 and 13 of the hub 11
of the needle 3 so as to cause them to be contracted, thereby causing
said lugs to be connected inside the hole or seat 20 and a locking
of the tooth element 32 provided on one of the lugs, for example
the lug 13 with respect to the locking collar 31.
Thus, the needle is made rigid with the end portion of the piston.
By exerting a pulling force, and owing to the fact that the lugs
12 and 13 have been contracted, the legs 14 are disengaged from
the cut-out 10 thereby the needle can be also disengaged and caused
to be withdrawn inside the cylinder.
The provision of a single lug with a locking element, whereas the
other lug operates as a guide element, causes the needle, as it
is withdrawn inside the cylinder 11 to be tilted through few degrees,
usually about 5.degree..
Thus, the needle point will be laterally displaced, thereby the
needle can not be further withdrawn for a possible re-use of the
Moreover, as shown, the stem or rod 40 of the piston 4 is provided
with notches 41 at an intermediate portion thereof, allowing the
stem or rod to be easily broken, by removing the end portion including
the push-button element 42 in order to provide a pushing force.
With the disclosed arrangement, there is provided a very functional
syringe which can not be re-used, which is obtained by very simple
means and which, anyhow, is specifically adapted to allow the needle
to be always firmly held in its use position, whereas it is safely
disengaged as the piston is withdrawn again.
The invention as disclosed is susceptible to several modifications
and variations all of which will come within the scope of the inventive