Abstrict An improved disposable syringe, made up of a cylindrical and hollow
main body in which a piston can move that pushes the liquid to inject
the same through a needle coupled to the front end of the main body,
specifically to a neck established for this purpose in the same;
the needle being complemented by a cone for coupling to said concetric
neck provided at the front end of the main body; and the rear end
to a protective sheath of the needle being, in turn, coupled by
pressure to said cone in order to maintain sterilization of the
needle.
Claims What is claimed is:
1. A disposable syringe, comprising a substantially cylindrical
hollow main body in which a piston is movable to push a liquid;
said main body having a front end provided with a neck; a needle
having a rear end facing said neck of said main body; a protective
sheath removably arranged over said needle, said needle being provided
with a conical element having one portion cooperating with said
sheath so as to provide a hermetic sealing between said needle and
said sheath and another portion cooperating with said neck of said
main body so as to hold said needle in said main body.
2. A disposable syringe as defined in claim 1 wherein said neck
of said main body has a radially inner wall and a radially outer
wall which are spaced from one another so as to define a channel
therebetween, said other portion of said conical element being inserted
in said channel between said walls of said neck.
3. A disposable syringe as defined in claim 2 wherein said other
portion of said conical element is located in said channel and engages
with said outer wall of said neck of said main body.
4. A disposable syringe as defined in claim 3 wherein said other
portion of said conical element has an engaging formation, said
outer wall of said neck of said main body having an inner surface
provided with a plurality of engaging formations with which said
engaging formation of said conical element cooperates.
5. A disposable syringe as defined in claim 2 wherein said inner
wall of said neck of said main body has a frusto-conical shape.
6. A disposable syringe as defined in claim 2 wherein said outer
wall of said neck of said main body has a conical inner surface
converging in a direction away from said needle.
7. A disposable syringe as defined in claim 3 wherein said other
portion of said conical element has a radially inner surface abutting
against said inner wall of said neck of said main body.
8. A disposable syringe as defined in claim 1 wherein said neck
has a radially inner wall and a radially outer wall which are spaced
from one another so as to form therebetween a channel in which said
other portion of said conical element is introduced, said inner
wall of said neck being conical and complimentary to said conical
element, said inner wall of said neck having an outer conical surface
which is complimentary to said conical element, while said outer
wall of said neck has an inner surface which is also conical and
engages with said other portion of said conical element.
9. A disposable syringe as defined in claim 8 wherein said sheath
has a rear rim which has a size such that it can not be inserted
into said channel between said inner and outer walls of said neck
of said main body.
10. A disposable syringe, comprising a substantially cylindrical
hollow main body in which a piston is movable to push a liquid;
said main body having a front end provided with a neck; a needle
having a rear end facing said neck of said main body; a protective
sheath removably arranged over said needle, said needle being provided
with a conical element having one portion cooperating with said
sheath so as to provide a hermetic sealing between said needle and
said sheath and another portion cooperating with said neck of said
main body so as to hold said needle in said main body, said other
portion fo said conical element having an inner surface abutting
against an outer surface of said inner wall of said neck of said
main body, and an outer surface abutting against an inner surface
of said protective sheath, and also a radially outwardly extending
formation cooperating with radially inwardly extending formations
provided on an inner surface of said outer wall of said neck.
11. A disposable syringe as defined in claim 10 wherein said conical
element being formed as a circumferentially closed element.
Description OBJECT OF THE INVENTION
The invention refers to a disposable syringe that has been improved
in determinate structural aspects with the object of achieving better
performance and greater functional effectiveness than conventional
syringes.
The object of the invention is to obtain a disposable syringe of
the type comprising a main body in which the chamber for the liquid
to be injected is determined, and a needle with a coupling cone
on the end of said main body. The needle is complemented by a kind
of sheath that protects and sterilises it. The syringe includes
peculiarities with respect to the system for coupling the cone to
the main body and coupling the protective sheath of the injection
needle which, obviously, complements the assembly.
BACKGROUND OF THE INVENTION
There is a type of disposable syringe made up of a cylindrical,
hollow body, which is open at its rear end to allow the movement
of a rod corresponding to a piston that moves inside said cylindrical
body for pushing and/or absorbing the liquid. The cylindrical body
determines a chamber between its front end and the piston that can
move axially in the same. Said axial rod ends in a kind of flattening
or expansion to allow it to be manually actuated by the user.
This type of syringe is complemented by the corresponding needle
which is housed in a covering in the form of a hood or sheath that
constitutes a means for protecting the needle and also achieving
hermetic sealing and the corresponding sterilisation, since the
needle has a cone on its rear end for coupling to the corresponding
end or neck established for this purpose on the front end of the
main body of the syringe. The rear end of the sheath meets the perimeter
of said coupling cone, thus achieving a hermetic seal and maintaining
sterilisation of the needle, so that when the unit is going to be
used, it is sufficient to couple the needle holder which slightly
protrudes with respect to the rear end of the sheath over the neck
of the body of the syringe, and then to extract or separate the
sheath for the syringe to be ready to use.
As is clear, the coupling between the cone of the needle and the
neck of the body of the syringe must be watertight to keep the liquid
insulated inside the main body of the syringe, or what amounts to
the same thing, in its corresponding chamber.
However, sometimes during handling, in the coupling and subsequent
extraction of the protective sheath of the needle, a slight uncoupling
and/or mobility of said cone occurs with respect to the neck of
the body of the syringe, thus losing its hermetic seal and making
it possible for air to enter the chamber, or even an unwanted exit
of liquid.
When the protective sheath of the needle is being separated, it
may also become badly aligned due to the tilting that may occur
on the coupling cone, all of which means the risk of losing water-tightness
of the liquid to be injected, or even problems of another kind with
respect to the effectiveness and proper insertion of the needle
in the muscular mass of the patient, as well as an irregular injection
of liquid.
DESCRIPTION OF THE INVENTION
The syringe of the type referred to in the foregoing section, has
a series of peculiarities on the basis of which the problems and
drawbacks mentioned above are resolved.
More specifically, the first novel characteristic of the syringe
of the invention is that the neck provided in the front end of the
main body of the syringe, upon which the cone of the needle must
be coupled, projects lengthwise with respect to the end in which
the front end or part of the body extends, to define a large ring-shaped
channel between said extension and the neck of the coupling. In
said ring-shaped channel the rear end of the cone is housed, as
well as the rear end of the sheath, although it is limited in its
penetration in order to be able to separate it afterwards.
Another novel characteristic, is that the front extension of the
main body of the syringe has an inner helicoidal fluting which determines
a kind of thread for holding a ring-shaped rim provided in the rear
part of the coupling cone. The latter thus remains completely held
in place once it has been inserted into the concentric neck of the
main body of the syringe, which makes it possible to extract and
separate the sheath once the cone of the needle is coupled by pressure
since, logically, to prevent the loss of water-tightness and therefore
maintain sterilisation of the needle until it is to be used, the
latter must be coupled to the body of the syringe with the sheath
fitted and then finally extracted. Said sheath also includes a perimetric
rear rim, which stops against the inner, slightly trunco-conical
surface of the extension provided with the helicoidal fluting mentioned
above, as the cone fits onto a complementary conical surface corresponding
to the concentric neck of the main body. The liquid to be injected
exits, pushed by the piston, through said neck and is injected by
means of the needle that is coupled in the way described above.
In this way, an effective hermetic or watertight seal is achieved
in the coupling of the cone to the body of the syringe, which will
remain permanently intact since said cone is held in place by the
inner fluting of the axial extension of the syringe's body, thus
allowing the sheath to be extracted by pulling outwards without
the coupling cone undergoing any movement or tilting during this
operation of separation of the sheath.
DESCRIPTION OF THE DRAWINGS
To complement the description being given and in order to promote
a fuller understanding of the features of the invention, in accordance
with a preferred practical embodiment of the same, a set of drawings
are attached as an integral part of said description, in which,
illustratively and non-restrictively, the following is represented:
FIG. 1 shows an exploded view of the main body of the syringe that
is the object of the invention, as well as of the assembly made
up of the needle with its coupling cone and the protective sheath
of the same.
FIG. 2 shows a view in longitudinal cross-section at 1/4 of the
syringe assembly, when the cone of the needle is coupled to the
corresponding neck provided on the front end of the main body of
the syringe, the sheath being in fitted position but ready for separation.
PREFERRED EMBODIMENT OF THE INVENTION
As may be observed in said drawings, the disposable syringe of
the invention is made up of a main hollow cylindrical body, which
is open at its rear end to allow the introduction of a piston for
pushing the liquid to be injected. Between said piston and the front
end of said main body the chamber for the liquid is established.
Said front end of the main body (1) has an axial concentric neck
(2) with a slightly trunco-conical shape while, externally to said
neck (2), the body (1) has an extension (3) that is slightly shorter
than the neck (2), a deep channel (4) being established between
both of them. The wall (5) of said channel (4) converges downwards,
that is, it defines an inverted conicality, with the peculiarity
that in the surface of said inverted conical wall (5) a helicoidal
fluting (6) is provided that determines a thread for effectively
holding a cone (7) to carry the injection needle (8). Said cone
(8) determines the means of coupling said needle to the main body
of the syringe, with the peculiarity that said cone (7) has a perimetric
rim or flattening (9) at its rear end which, when coupling or axial
sliding on the neck occurs, causes a threading on the helicoidal
fluting (6) of the inner conical surface (5) of the axial outer
wall (3) of the body (1) of the syringe, thus fitting together the
coupling cone (7) and the neck (2) of the body of the syringe by
pressure, and therefore hermetically, and thus ensuring that the
covering established by said body of the syringe (1) is watertight.
It is desirable that this type of needle (8) with its coupling
cone (7) are complemented by a protective sheath (10) to maintain
sterilisation and protection of the needle itself (8), which is
coupled externally and by friction to the outer surface of the coupling
cone (7). Therefore the separation of releasing of said sheath (10)
is carried out once the cone (7) is coupled to the neck (2). In
said coupling, logically and as may be observed in FIG. 2 the rear
part, in which a flattening (11) of the sheath (10) is established,
is housed in the channel (4) that determines the concentric neck
(2) and the outer wall determined by the extension (3). The outer
edge of said flattening (11) is stopped against the inner conical
surface (5) of the wall (3), thus preventing, during said coupling,
the sheath (10) from pressing excessively on the coupling cone (7),
which allows the sheath (10) to be easily extracted once said cone
(7) is coupled and held in place, without tilting, movement or loosening
of the coupling cone (7) on the neck (2) of the syringe body (1)
occurring during said operation. |