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 sterilisation of the
needle.
Claims 1. 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 concentric neck provided at the front end of the main body;
and the rear end of a protective sheath of the needle being, in
turn, coupled by pressure to said cone in order to maintain sterilisation
of the needle, characterised in that the axial and concentric neck
in which the front end of the syringe body is extended is complemented
by an outer wall which is an extension of the main body itself;
the inner surface of this wall is inverted trunco-conical and determines
together with the concentric neck, which is trunco-conical in shape,
a deep channel for receiving the rear part of the coupling cone
of the needle and the rear part of the protective sheath of said
needle. The axial and concentric neck of the main body has a conicality
that is complementary to that of the coupling cone of the needle
in order to fit both elements together hermetically, remaining held
in the coupling of said cone by the setting of a perimetric rear
rim of the same in a helicoidal fluting, in the form of a thread
provided in the inner side corresponding to the inverted cone shape
of the outer wall in which the main body extends, and whose inverted
trunco-conical surface determines in turn a stopping means for a
perimetric rear rim of the sheath itself, preventing the latter
from moving towards the inside of the channel, and thus making it
easy to separate it from the coupling cone once the latter is fitted
tightly onto the axial and concentric neck of said main body of
the syringe.
Description OBJECT OF THE INVENTION
[0001] 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.
[0002] 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
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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
[0012] 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:
[0013] 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.
[0014] FIG. 2 shows a view in longitudinal cross-section at {fraction
(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
[0015] 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.
[0016] 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.
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