Safety syringe abstract
The present invention relates to a safety-syringe providing a needle
with a hollow core having a spring coiled around the needle. The
spring is capable of expanding to retract the needle into the body
of the syringe. A pressure hinge is provided with a plurality of
teeth-shaped triggers for retaining the needle in a position for
use and for preventing the piston from moving after use. Further,
a vacuum may be provided within the piston for facilitating in the
retraction of the needle into the syringe.
Safety syringe claims
I claim:
1. A single-use safety syringe comprising:
a body for containing a fluid, said body having a projection and
a chamber;
a needle having a head end and a hollow core for receiving the
fluid, said head end being positioned in said chamber below said
projection when the syringe is in use;
piston means positioned in said body above said needle for pushing
the fluid into said needle when the syringe is in use;
a spring coiled around said needle below said head end and positioned
in contact with said head end and said body, said spring expanding
after use of the syringe so that said needle is propelled into the
upper end of said body above said projection; and
a pressure hinge positioned on said projection having a plurality
of teeth-shaped triggers, said piston means having at its lower
end retention means engaging the inner wall of said chamber in the
vicinity of said triggers, whereby said triggers both retain said
head end below said projection to prevent expansion of said spring
as the syringe is in use and bear against said retention means to
prevent motion of said piston means after deformation of said triggers
by said piston means and expansion of said spring.
2. A single-use safety syringe according to claim 1 wherein said
piston means comprises a piston having a hollow core and an upper
and lower end, said lower end being sealed by a membrane, said piston
having a cylindrical wall around said membrane which wall pushes
against said triggers to cause the deformation of said triggers
after use of the syringe.
3. A single-use safety syringe according to claim 2 wherein said
head end of the needle has a cutting crown which faces said membrane
of said piston for piercing the membrane.
4. A single-use safety syringe according to claim 1 wherein the
inner wall of said chamber has notches therein in the vicinity of
said triggers and said retention means comprises peripheral relief
member on said piston means which engage said notches.
5. A single-use safety syringe according to claim 2 wherein said
hollow core has a diameter which is approximately equal to the diameter
of said head of the needle so that said needle is received in said
hollow core after said spring has expanded.
6. A single-use safety syringe according to claim 3 wherein said
hollow core has a vacuum, so that when said cutting crown pierces
said membrane said vacuum serves to facilitate the retraction of
said needle into said hollow core.
Safety syringe description
Once used, this syringe is rendered unsuable automatically, thereby
making it impossible for further use.
The syringe is made of a cylindrical receptor for the product to
be injected and a propelling piston. The injectable needle features
a head which is housed into a extension of the body of the syringe,
thus becoming secured by a device conformed by several triggers
which become unhooked when the piston reaches its maximum run.
The head of the needle features a cutting device which punches
the membrane closing the piston's hollow chamber, where a vacuum
was created previously, such that once the membrane is punctured
the needle is absorbed into the piston's hollow core assisted by
an expansion spring leaning against the head. With the needle inside
the piston, the syringe can not be reused.
When the piston reaches it longest run, it becomes engaged and
can not be recuperated.
DESCRIPTION OF INVENTION
The object of the invention is a single-use safety syringe, namely
a syringe that is rendered useless after a single use, such that
it may not be reused. This is achieved by retracting the needle
into the piston's hollow core.
The purpose of the invention is to make a contribution toward an
improved and safer use of injectable medication, thus reducing accidents
and contagion derived from improper handling.
The syringe is made of the following components:
a) Outer body, which in turn is composed of:
Retaining chamber of the propeller spring.
Expansion (not essential) for the needle.
Expansion to engage the retention hinge.
Second expansion (dentate) to retain and block the piston.
b) Piston, made of the following parts:
Main body (hollow cylinder) with a proximal circular expansion
fitted with a dentate border for blocking. Inner lumen equal to
the outer diameter of the head of the needle.
Distal membrane, forming the proximal wall of the piston, for appropriate
push of injectable fluids, and contributing to the formation of
a vacuum within the piston.
Vacuum hole, permits forming a vacuum.
c) Needle, made of the following parts:
Puncture tube (according to standard calipers).
Sliding puncturing body. It's function is to punch the membrane.
It may be propelled by the spring to slide within the piston's hollow
core and/or become aspirated by the vacuum effect within the piston.
Likewise, it also features a narrow passage which allows fluid
displacement into the needle, and retains the body of the needle
though the teeth of the retention hinge.
d) Retention hinge: its object is to retain the needle body when
it is mounted, likewise it also blocks the body until the piston
wall releases the body c), by pressing the outermost ends of the
three teeth.
This device has the shape of a crown, with three retention teeth
or triggers come off its central core, continuing on in a "V"
arrangement with such an inclination that their retraction is possible.
e) Propeller spring: When the spring is released it is slightly
longer than the portion of the needle that is lodged outside the
sliding body of the needle, thus ensuring its lodging into the watertight
compartment within the device.
f) Membrane: Its function was referred to in section b). It is
worth noting its low degree of porosity and hardness, as well as
its scarce thickness and high fragility in order not to be extremely
resistant to punching.
DESCRIPTION OF DRAWINGS
In order to improve understanding of the invention, a set of two
drawings representing the single-use safety syringe in two different
positions is enclosed along with this memorial:
FIG. 1: Represents a longitudinal section of the syringe with all
its components arranged for use as if it were a normal hypodermic
syringe.
FIG. 2: Represents the hypodermic syringe showing the needle already
retracted.
DETAILED DESCRIPTION
As can be seen from the drawings, the hypodermic syringe presents
at one end of its body (1), an expansion for the needle (2), the
lodging (3) where the head of the needle (4) is secured, which is
fitted with lateral passages (5) allowing for medication flow into
the needle's inner core (2). The head of the needle (4) is secured
into ready-for-use position by a pressure hinge (6) retained in
place by an expansion (7) of the body, whose hinge is provided by
three or more teeth (8) arranged as triggers, thus retaining the
head of the needle against the opposite effect of the expansion
spring (9) coiled around an extension (10) of the body, between
the bottom of the extension and the head (4) of the needle (2).
The piston (11) is made of a hollow body with its lower end sealed
by a membrane (12) and by a cylindrical wall (13) used for pushing
against the retention teeth of the head (4) and of the needle (2)
at the end of the run of the piston (11).
The head (4) of the needle (2) conforms a cutting crown (14) which
faces the membrane (12) of the piston.
The cylindrical expansion of the piston (11) presents a peripheral
relief (15) on the area of contact of the walls of the body which
is to fit into the corresponding notch (16) located near the triggers
(8) of the needle (2).
The lumen (17) of the piston (11) presents a diameter similar to
that of the head (4) of the needle (2), in order to allow for its
lodging when propelled by the spring (9).
The vacuum is produced in the lumen (17) of the piston (11), which
is closed by an airtight cap (18) facilitating penetration of the
head (4) of the needle (2) when it is released, the push of the
spring helps in this retraction. |