Disposable syringe with needle cover including a slidable needle
cover preventing contact of the user with the needle and preventing
re-use of the assembly.
1. A disposable syringe with needle cover of the type comprising,
in combination, a straight axis cylindrical main hollow body, shiftably
and tightly housing a plunger passing through the lower open end
thereof, while from the center of the opposed end a conical and
coaxial hollow nozzle projects, the inner conduit of which communicates
to the interior of the needle coupling means, wherein, between said
coaxial hollow nozzle of the main hollow body and the needle coupling
means there is a coaxial insert having a standard plugging cone
at its central region; said insert being housed in the interior
of a hollow, shiftable and coaxial hollow needle cover, having a
length longer than the needle plus its coupling means, and of a
length greater than that of the main body; said needle cover having
a wholly opened lower end as well as means for being removably retained
with respect of the main body and means for retaining the coaxial
insert, wherein said coaxial hollow nozzle of the main cylindrical
body is surrounded by an annular wall, the inner surface of which
is conical, a peripheral cavity being defined with respect to said
nozzle, the size of which is slightly smaller than the peripheral
annular portion defined around the plugging cone of the coaxial
2. A disposable syringe as claimed in claim 1 wherein means for
removably retaining the needle cover of the main body are a lower,
outer annular flange, of a diameter higher than the lower hollow
end diameter of the needle cover, along with an inner upper annular
projection defined at the needle cover, the diameter of which is
slightly greater than the outer diameter of the main cylindrical
3. A disposable syringe as claimed in claims 1 wherein said coaxial
insert plugging cone has an inner shape similar to said upper hollow
nozzle of the main body and slightly smaller than that of said nozzle.
4. A disposable syringe as claimed in claim 1 wherein the outer
shape of the plugging cone of the coaxial insert is slightly smaller
than the standard coupling means of the needle and similar thereto.
5. A disposable syringe as claimed in claim 1 wherein the means
for retaining the coaxial insert of the needle cover comprises two
inner annular projections defined adjacent its lower end, separation
of which allows the tight housing of the outer annular flange of
BACKGROUND OF THE INVENTION
The instant invention relates to a disposable syringe with needle
cover, of the type ready to be used; the needle and its corresponding
protecting sheath as well as the remaining parts and forming elements
being also ready to be used and being sterilized. The advantage
of the syringe of the invention is that the user will have no contact
with the needle or surrounding regions, before, during and after
the injection; the assembly being completely disabled thereafter.
More particularly, the instant invention relates to a syringe of
the above mentioned type comprised by a main cylindrical, hollow
body, having a solid plunger displacing therein, which is located
coaxially, the inner space of said cylindrical main body constituting
the transient housing of the liquid or medicine to be injected,
as well as of blood or other liquids to be withdrawn from the body,
in accordance with the displacement direction of such plunger.
As already known, such main cylindrical body has a wholly opened
base defining an opening from which the rear end of said coaxial
plunger projects, such plunger being characterized by having an
annular flange in order that the user may push or pull manually
the plunger, according to the desired action. The inner end or head
of the plunger tightly fits inside the walls and at the bottom of
said main body, such that the variable volume chamber defined therein
is always tight and isolated from the outside. Said bottom has,
in turn, an outer frusto-conical hollow and coaxial nozzle converging
towards its outer end, constituting the plugging means for coupling
and fixing the injection needle.
This conical coupling means is standard in conventional syringes
and is called "plugging cone" or "luer cone".
To this end, needles which may be placed separately, housed inside
a protecting sheath keeping them duly isolated and sterilized, have
at their rear end the corresponding coupling means integral with
the needle, such coupling means having its inner surface mating
with said plug at the "luer cone", while the outer surface
serves for removably coupling said sheath protecting the needle.
Considering the highly contagious diseases, specially those being
transmitting through blood, the present approach is to attain disposable
and disabled syringes, thus assuring whole sterility and reliance
to patients. Several embodiments are already known in which the
syringe and needle are disabled after their use.
Nevertheless, there is no embodiment protecting and assuring the
impossibility of infection to the person applying the injection
to the patient, specially taking into account that such person is
that handling the syringe with the risk of an undesired puncture
or of contacting small blood droplets from the patient when introducing
or withdrawing the needle. When injecting with known syringes, the
assembly is withdrawn pulling outward syringe and needle. In this
way, accidental punctures may occur, thus causing leakages of blood
or of the liquid injected on the patient's skin, on the hands the
user, on clothes or other elements used for applying the injection,
all of which may imply contamination.
SUMMARY OF THE INVENTION
The syringe of the instant invention offers an efficient solution
to both problems. Its constructive features prevent the possibility
of re-use and include simultaneously a shiftable needle cover avoiding
all contact of the user with the needle. In fact, such needle cover
is an end cylindrical body coaxially surrounding the main body,
being shiftable longitudinally therealong, until it is located as
axial projection of the syringe along a portion long enough such
as to house the needle used, without any risk of dangerous leaks;
further, handling of the syringe will be safe, avoiding accidental
punctures, splits or other dangerous situations.
The invention also includes an insert between the syringe plugging
cone and the needle plugging cone. This insert has two essential
features influencing the general operation of the syringe: the first
is that, being coupled to the upper end of the syringe, it provides
the standard "luer cone" for coupling the needle and,
the second one is that it has an outer annular flange engaged to
inner lower retention means of the needle cover, such that, after
the injection is effected, when the needle cover is withdrawn and
disposed, this cover entraps the needle which is retained by such
means. It is clear that the user may never contact the needle.
Further, the insert, as mentioned, is that having the "luer
cone" and not the syringe. Therefore, the syringe is also disabled
and cannot be used again since it does not longer have the proper
plugging cone for receiving a conventional needle.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred, non-limiting, embodiment of the invention will be
hereinbelow described in connection with the accompanying drawings,
FIG. 1 is a longitudinal and axial section of a disposable syringe
with needle cover, before being used, according to the instant invention;
FIG. 2 is a section similar to that of FIG. 1 showing the forming
elements, with the needle already applied to the patient and the
syringe plunger in a position for injecting the liquid product;
FIG. 3 is the same section, but indicating the way in which the
needle cover acts during the withdrawal action of the syringe;
FIG. 4 is another longitudinal section, similar to former ones,
indicating the way in which the two main portions of the syringe
of the invention are separated and disabled.
In all figures, the same reference numerals designate the same
or equivalent elements.
DETAILED DESCRIPTION OF THE INVENTION
As may be seen in all figures, the syringe is comprised by a main
hollow cylindrical body 1 a plunger penetrating and displacing
tightly through the open end of the body 1 thus defining a variable
volume chamber 3 which is filled with the liquid or medicine to
be injected to the patient, using the needle 4 to this end.
The novelty of the invention resides in the needle coupling along
with the use of a needle cover.
In fact, said main body 1 has at its closed end, opposed to the
mouth, a small conical nozzle 6 and an annular wall having a diverging
inner surface 7 defining the pressure, removable seating means of
a novel and particular insert 8 in which a plugging cone is located
9 whose dimensions are those established for the removable coupling
of the needle through its integral joining means 10.
The conical nozzle 6 as well as the plugging cone 9 have an inner
conduit axially communicating with the interior of the main body
1 wherein the liquid to be injected is contained.
The assembly also has an outer cylindrical needle cover 15 which
is coaxial to the main body 1 and the plunger 2 which has a longer
length and is shiftable with respect to said main body; having in
turn two inner lower annular projections 12 and 13 constituting
means for retaining the insert 8 as will be explained hereinbelow,
as well as an upper inner annular flange 11 holding the insert in
a stable position prior to use and, finally, a lower and outer annular
lug 14 is provided in order that the user may displace the needle
cover with respect to the main body, or vice-versa, i.e. displace
the main body with respect to the needle cover.
The user, after removing sheath 15 protecting needle 4 introduces
the needle into a patient P, as shown in FIG. 2 after which, bearing
the front end of the needle cover on the patient's skin, the medicine
is injected displacing plunger 2 in the direction F1.
With reference to FIG. 3 the novel protecting action of this embodiment
may be seen. Through the use of the mentioned annular lug 14 the
user retains the needle cover 10 on the patient's skin and displaces
outwardly and simultaneously the needle 4 and the main body 1 which
are engaged; this is carried out by a movement in the direction
indicated at F2. In this step, the needle is integral to the main
body through the action of said insert 8 engaging both elements
as mentioned above and shown in the three first figures.
It is clear, from FIG. 3 that any undesired splash produced along
with the removal of said needle is confined at the interior of the
needle cover 16 preventing any possibility of contact with the
With reference to FIG. 4 the operation of the syringe of the invention
at the last step of the injection may be understood. Maintaining
the needle cover 16 on the patient's skin, the main body is displaced
1 in the direction indicated by F2 which produces withdrawal of
said main body 1 with respect to the needle, since insert 8 offers
a very low resistance to traction in this direction. Simultaneously,
the same insert 8 is retained at the inner space of the needle cover
the user having not contacted the needle. To this end, projections
12 13 act along with an annular flange 17 of the novel insert 8.
Therefore, the disposable feature of the syringe of the invention
may be understood by the use of the needle cover 16 along with insert
8 which, as mentioned above, forms a "luer" standard cone
capable of retaining the needle 4 by plugging and, in turn, cone
9 has a special shape in its inner conical cavity allowing the removable
coupling on said conical nozzle 6 of the main body.
Measures and proportions of conical nozzle 6 are not the conventional
ones for retaining injection needles such that, said separated syringe
portion may not be used again since it is impossible to place another
Regarding retention elements designated with reference numerals
11 12 13 7 and 17 it is to be note that they correspond to a
constructive embodiment chosen as example of the invention, but
equivalent resources may be used for the same function.
It will also be noted that in FIGS. 1 2 and 3 the lower portion
of the needle cover, wherein retention means 12 and 13 are located,
the needle cover body has a slightly diverging shape, since it has
a compressive resilient tendency in order to cooperate with coupling
and retention of insert 8; which, upon being withdrawn from the
main body 1 confines its annular flange 17 between said means 12