Safety syringe abstract
A safety syringe includes a glass syringe body, a plunger slidable
inside the syringe body and provided at the rear with a manually
operable stem, an injection needle mounted at the front end of the
syringe body, a sheath mounted integrally on the syringe body, a
sleeve mounted slidably on the sheath to pass from a retracted use
position to an advanced safety position, in which the needle is
protected by the sleeve, locking elements mutually provided in the
sheath and in the sleeve to lock the sleeve in position when it
is in the retracted use position and in the forward safety position,
and operating elements integrally mounted with the stem of the piston
to cooperate with locking elements so as to allow movement of the
sleeve from the retracted use position to the advanced safety position.
Safety syringe claims
11. A safety syringe (100) comprising: a glass syringe body (1)
hollow on the inside and open at the front and rear, a plunger (2)
slidable inside the syringe body (1), said plunger being provided
at the rear with a manually operable stem (20) brought out of the
syringe body by means of the rear end (21) thereof, and an injection
needle (11) mounted at the front end (10) of the syringe body (1),
characterized in that it comprises: a sheath (3) integrally mounted
on said glass syringe body (1), a sleeve (4) slidably mounted on
said sheath to pass from a retracted use position in which the needle
(11) protrudes forward from said sleeve to be able to perform the
injection to an advanced safety position in which the needle (11)
is protected by said sleeve (4), locking and stop means, mutually
provided in said sheath and in said sleeve to lock said sleeve (4)
in position when it is in said retracted use position and said advanced
safety position, and operating means (22) integrally mounted to
the rear part of the plunger stem (20) to cooperate with said locking
means, when the plunger (2) is at the end of the injection stroke
to allow movement of said sleeve (4) from the retracted use position
to the advanced safety position.
12. A safety syringe (100) according to claim 11 wherein it comprises
spring means (6) interposed between said sleeve (4) and said sheath
(3).
13. A safety syringe (100) according to claim 12 wherein one end
of said spring means is in abutment against an annular abutment
surface (42) defined between a larger diameter part (40) and a smaller
diameter part (41) of said sleeve and the other end of said spring
means is in abutment against an annular abutment surface (35) defined
by a collar (30) protruding outward at the fore end of said sheath
(3).
14. A safety syringe (100) according to claim 12 wherein said
locking means comprise two teeth (31) radially protruding from said
sheath, in diametrically opposite directions, to engage in respective
slots (44) provided in two rear elastic tongues (43) longitudinally
formed in the rear part of the side wall of said sleeve (4).
15. A safety syringe (100) according to claim 14 wherein each
of said rear tongues (43) is defined by two longitudinal parallel
notches formed in said side wall of the sleeve, up to the rear end
of the sleeve, and the rear end of said tongues (43) protrudes radially
beyond the rear end of the sleeve.
16. A safety syringe (100) according to claim 14 wherein said
operating means comprise a frusto conical block (22) cooperating
with said rear tongues (43), when the plunger (2) reaches the end
of the injection stroke, in order to make them diverge outward to
disengage said teeth (31) of the sheath from said slots (44) of
the rear tongues.
17. A safety syringe (100) according to claim 12 wherein said
stop means comprise a pair of flexible central tongues (47), longitudinally
provided in diametrically opposite positions in the central part
of the side wall of said sleeve (4), said central tongues (4) being
provided with respective teeth (49) protruding inward to engage
in respective longitudinal grooves (32) provided in said sheath
(3).
18. A safety syringe according to claim 17 wherein each of said
longitudinal grooves (32) in the sheath (3) has a rear abutment
surface (33) which abuts against the respective tooth (49) of the
central tongues of the sheath when said sheath (4) is in the retracted
use position and a front abutment surface (34) that abuts against
the respective tooth (49) when said sleeve (4) is in the advanced
safety position.
19. A safety syringe (100) according to claim 12 wherein said
stop means comprise a pair of flexible rear tongues (50), longitudinally
provided in diametrically opposite positions in a rear part of the
side wall of said sleeve, said central tongues (50) being inwardly
convergent and having an abutment surface (52) able to abut against
the front end of said sheath (3), when the sleeve (4) is in said
advanced safety position.
20. A safety syringe (100) according to claim 19 wherein each
of said central tongues (47) and each of said front tongues (50)
is defined by a respective substantially U-shaped notch (48 51)
formed respectively in the central part and in the front part of
the side wall of said sleeve.
21. A safety kit comprising a sheath (3), a spring (6), a sleeve
(4) and an operating means (22), to be applied to a syringe to make
it a safety syringe.
22. A safety kit according to claim 21 wherein: said sheath (3)
is integrally mounted on the syringe body (1), said sleeve (4) is
slidably mounted on said sheath (3) to pass from a retracted use
position in which a needle (11) mounted on the front end of the
syringe body (1) protrudes forward from said sleeve to be able to
perform the injection, to an advanced safety position in which the
needle (11) is protected by said sleeve (4), said spring (6) is
interposed to act between said sleeve (4) and said sheath (3), said
operating means are integrally mountable to the rear part of a plunger
stem (20) of the syringe, locking and stop means being mutually
provided in said sheath (3) and in said sleeve (4) to lock said
sleeve in position when it is in said retracted use position and
said advanced safety position, said operating means cooperating
with said locking means, when the plunger is at the end of the injection
stroke to allow movement of said sleeve (4) from the retracted use
position to the advanced safety position.
23. A safety kit according to claim 22 wherein said locking means
comprise two teeth (31) radially protruding from said sheath, in
diametrically opposite directions, to engage in respective slots
(44) provided in two rear elastic tongues (43) longitudinally formed
in the rear part of the side wall of said sleeve (4).
24. A safety kit according to claim 22 wherein said operating
means comprise a frusto conical block (22) cooperating with said
rear tongues (43), when the plunger (2) reaches the end of the injection
stroke, in order to make them diverge outward to disengage said
teeth (31) of the sheath from said slots (44) of the rear tongues
25. A safety kit according to claim from 22 wherein said stop
means comprise a pair of flexible central tongues (47), longitudinally
provided in diametrically opposite positions in the central part
of the side wall of said sleeve (4), said central tongues (4) being
provided with respective teeth (49) protruding inward to engage
in respective longitudinal grooves (32) provided in said sheath
(3).
26. A safety kit according to claim 25 wherein each of said longitudinal
grooves (32) in the sheath (3) has a rear abutment surface (33)
which abuts against the respective tooth (49) of the central tongues
of the sheath when said sheath (4) is in the retracted use position
and a front abutment surface (34) that abuts against the respective
tooth (49) when said sleeve (4) is in the advanced safety position.
27. A safety kit according to claim 22 wherein said stop means
comprise a pair of flexible front tongues (50), longitudinally provided
in diametrically opposite positions in a front part of the side
wall of said sleeve, said front tongues (50) being inwardly convergent
and having an abutment surface (52) able to abut against the front
end of said sheath (3), when the sleeve (4) is in said advanced
safety position.
Safety syringe description
[0001] The present invention refers to a glass syringe, of the
disposable type, provided with an automatic safety device to protect
the needle once the injection has been preformed. The present invention
also refers to a relative safety kit that can be applied to a disposable
glass syringe.
[0002] A syringe generally comprises a cylindrical body open at
the rear to receive a plunger. An internally hollow needle is mounted
at the head of the syringe body.
[0003] Because of health regulations and to avoid transmission
of infectious diseases, syringes must generally be used only once
and then discarded. For this reason, there is a growing demand for
disposable syringes adapted to prevent further use.
[0004] Moreover, syringes generally present drawbacks from the
point of view of safety. In fact, once the syringe has been used,
the needle remains exposed at the head of the syringe body, with
the risk of injuries or accidental needle sticks.
[0005] To overcome these drawbacks, plastic disposable syringes
having safety devices to cover the needle are available on the market.
[0006] Patent application PCT WO 99/37345 describes a disposable
safety syringe which has a needle covering sleeve mounted axially
on the syringe body and slidable from a retracted position in which
it leaves the needle exposed to allow injection, to an extended
position in which it completely covers the needle, preventing re-use
of the syringe and acting as a protection against accidental needle
sticks.
[0007] Once the injection has been performed, the sleeve is automatically
brought into the extracted safety position, by means of an automatic
mechanism and without any intervention by the user.
[0008] Glass syringes, on the other hand, are generally designed
to be able to be reused. In fact, the glass syringe body can be
sterilized at high temperature. For this reason, glass syringes
generally do not provide any safety device for protection of the
needle once the injection has been performed.
[0009] As is known, prefilled syringes in which the solution is
already inside the barrel of the syringe, ready for injection, are
widely available on the market. However, there exist some solutions
such as vaccines, antidotes and the like which cannot be stored
in plastic containers. Consequently, said solutions must necessarily
be placed in prefilled glass syringes.
[0010] For this reason and for reasons of hygiene and practicality,
glass syringes of the disposable type exist on the market. Disposable
glass syringes have the drawback of not having a safety device for
protection of the needle.
[0011] An object of the present invention is to eliminate the prior
art drawbacks providing a glass safety syringe that is practical,
versatile, economical and simple to make.
[0012] Another object of the present invention is to provide such
a glass safety syringe of the disposable type that is able to prevent
further attempts at use.
[0013] Another object of the present invention is to provide such
a glass syringe that is extremely safe and able to prevent accidental
injury and tampering after use.
[0014] These objects are achieved in accordance with the invention
with the characteristics listed in appended independent claim 1.
[0015] Advantageous embodiments of the invention are apparent from
the dependent claims.
[0016] The syringe according to the invention comprises a glass
syringe body hollow on the inside and open at the front and the
rear, a plunger slidable inside the syringe body and provided at
the rear with a manually operable stem and an injection needle mounted
at the fore end of the syringe body.
[0017] To make this syringe a safety syringe according to the invention,
a sheath integrally mounted on the glass syringe body and a sleeve
slidably mounted on the sheath to pass from a retracted use position
in which the needle protrudes forward from the sleeve to be able
to perform the injection to an advanced safety position in which
the needle is protected by the sleeve.
[0018] Locking means and stops are provided reciprocally in the
sheath and sleeve such as to lock sleeve in position when it is
in the retracted use position and in the advanced safety position.
Operating means able to cooperate with the locking means when the
plunger is at the end of the injection stroke are fitted to the
rear part of the piston stem, to allow the sleeve to be moved from
the retracted use position to the advanced safety position.
[0019] The advantages of the syringe according to the invention
are obvious in that it allows a glass syringe to be made into a
safety syringe, by providing the possibility of covering the needle
with the sleeve once the injection has been performed.
[0020] Further characteristics of the invention will be made clearer
by the detailed description that follows, referring to a purely
exemplary and therefore unrestrictive embodiment thereof, illustrated
in the appended drawings, in which:
[0021] FIG. 1 is a top plan view of the safety syringe according
to the invention, in the position ready for use, with a needle-covering
cap mounted at the head of the syringe body;
[0022] FIG. 2 is an axial sectional view of the safety syringe
of FIG. 1 in which the syringe body and the piston stem are shown
in side view;
[0023] FIG. 3 is an axial sectional view taken along the sectional
plane III-III of FIG. 1 in which the piston stem is shown in side
view and in the end of injection position and the needle-covering
cap has been removed;
[0024] FIG. 4 is an axial sectional view, like FIG. 3 in which
the needle is in the safety position;
[0025] FIG. 5 is a perspective view, illustrating a sheath for
covering a syringe body.
[0026] The safety syringe according to the invention, denoted as
a whole by reference numeral 100 is described with the aid of the
figures.
[0027] The syringe 100 comprises a syringe body 1 (shown in FIGS.
2 and 4) made of glass. The syringe body 1 is substantially cylindrical
in shape, is hollow on the inside and has a cylindrical chamber
open at the front and rear. The body 1 has at its fore end a head
10 into which a needle 11 is sunk. The body 1 has at its rear end
a flange 12 that protrudes radially therefrom to facilitate gripping
by the user.
[0028] As shown in FIG. 3 a plunger 2 made of rubber can slide
axially with a tight seal in the cylindrical chamber of the syringe
body 1. The plunger 2 is supported at the fore end by a stem 20
made of glass or plastic. The stem 20 has at its rear end a flange
21 disposed on the outside of the syringe body 1 to be able to be
operated manually by the user.
[0029] In the rear part of the stem 20 a frusto conical block 22
disposed around the stem 20 near the flange 21 of the stem, is
provided. The frusto conical block 22 has a tapered side surface
with a diameter that increases toward the rear part of the stem
20.
[0030] The frusto conical block 22 can be formed integrally in
the rear part of the stem, or it can be a separate element to apply
to the stern 20. In this latter case, the frusto conical block 22
has an axial hole 24 to be forcibly inserted, from the front part
of the stem, until it abuts against the rear flange 21 of the stem.
In this case, the frusto conical block 22 has an annular groove
23 to be able to yield elastically.
[0031] A tubular sheath 3 that almost entirely covers the side
surface of the syringe body 1 is mounted on the syringe body 1.
As shown also in FIG. 5 the sheath 3 comprises at its fore end
a collar 30 which protrudes radially outward so as to define an
annular abutment surface 35.
[0032] Two teeth 31 that protrude radially outward in diametrically
opposite directions are provided on the collar 30. Two longitudinal
slots 32 disposed in diametrically opposite positions are provided
on the side surface of the sheath 3 level with the teeth 31. In
this manner, each longitudinal slot 32 defines a rear abutment surface
33 and a front abutment surface 34.
[0033] The sheath 3 is made of plastic material and is elastically
forced and fixed on the glass body 1. The syringe body 1 with the
sheath 3 integral therewith, is mounted axially slidably inside
a substantially cylindrical sleeve 4 hollow on the inside. In this
manner, the head 10 of the syringe body 1 protrudes forwardly and
axially from the sleeve 4 and a needle-covering cap 8 is fitted
to the head 10.
[0034] The sleeve 4 has a cylindrical rear part 40 with a greater
diameter and a cylindrical front part 41 with a smaller diameter,
so as to define on the inside an annular abutment surface 42. In
this manner, as shown in FIG. 2 a helicoidal compression spring
6 which winds around the sheath 3 is interposed between the annular
abutment surface 35 of the collar 30 of the sheath 3 and the annular
abutment surface 42 of the sleeve 4.
[0035] As better shown in FIG. 1 two rear tongues 43 are formed
in the side wall of the part 40 of the sheath with the largest diameter.
The rear tongues 43 are disposed longitudinally in diametrically
opposite positions and are flexible. Each rear tongue 43 has a rectangular
slot 44 within which the respective tooth 31 of the collar 30 of
the sheath snap engages, so as to firmly retain the sheath 3 inside
the sleeve 4.
[0036] Each rear tongue 43 is defined by two longitudinal parallel
notches 45 which reach the end of the part with the greatest diameter
40. In this manner, each rear tongue 43 can bend radially outward.
Furthermore, each rear tongue 43 has a rear part which protrudes
rearward beyond the rear end of the part with the largest diameter,
40. The rear end of each tongue 43 has a tapered surface 46 able
to cooperate with the tapered surface of the frusto conical block
22 of the stem.
[0037] At the rear end of the part with the greater diameter 40
a flange 55 protrudes radially to facilitate gripping by the user.
The rear flange 55 of the sleeve is not present in the area in which
there are the rear tongues 43 so as not to interfere therewith.
The flange 55 of the sleeve has in its rear wall an annular abutment
surface against which the rear flange 12 of the glass body 1 abuts.
[0038] In the lateral part of the part with the smallest diameter
41 of the sleeve two central tongues 47 are formed. The central
tongues 47 are disposed longitudinally in diametrically opposite
positions and are flexible. Each central tongue 47 is defined by
a substantially U-shaped notch 48 so as to be able to bend radially
outward.
[0039] Each central tongue 47 has an inwardly protruding tooth
49 able to engage in the respective longitudinal slot 32 of the
sheath 3. In this manner, when the syringe body 1 with the sheath
3 are inserted inside the sleeve 4 the central tongues 47 are widened
and then elastically snap back when the teeth 49 engage in the respective
slots 32 in the sheath.
[0040] Two front tongues 50 are formed in the side wall of the
sleeve part 41 with the smallest diameter. The front tongues 50
are longitudinally disposed in diametrically opposite positions.
Each front tongue 50 is defined by a substantially U-shaped notch
51 so as to be able to bend radially outward. Under normal conditions,
each front tongue 50 converges inwardly and has at its front end
an abutment surface 52.
[0041] Operation of the syringe 100 according to the invention
will now be described.
[0042] With reference to FIGS. 1 and 2 in an initial condition
the spring 6 is compressed between the annular abutment surface
35 of the collar 30 of the sheath 3 and the annular abutment surface
42 of the sleeve 4. The teeth 32 of the sheath are engaged in the
slots 44 of the rear tongues 43 of the sleeve avoiding any axial
movement of the sheath 2 and body 1 assembly with respect to the
sleeve 4. Furthermore, the teeth 49 of the central tongues 47 are
in abutment against the front abutment surface 33 of the longitudinal
slot 32 of the sheath, avoiding any axial rearward movement of the
sheath 3 with respect to the sleeve 4.
[0043] The chamber of the body 1 is pre-filled with a solution
to be injected. Thus, when the injection is performed and the plunger
2 reaches the end of its stroke in the chamber of the syringe body,
as shown in FIG. 3 the tapered surface of the frusto conical block
22 cooperates with the tapered surface of the rear end 46 of the
rear tongues 43 causing outward radial bending thereof.
[0044] Consequently, the teeth 31 of the sheath 3 disengage from
the slots 44 of the tongues 43 and the sleeve 4 is no longer firmly
constrained to the sheath 3 and syringe body 1 assembly. As a result,
as shown in FIG. 4 the spring 6 which was compressed is released,
lengthening and causing axial forward sliding of the sleeve 4 with
respect to the sheath and syringe body assembly, until the teeth
49 of the central tongues 47 of the sleeve abut against the respective
rear abutment surfaces 34 of the longitudinal slots 32 of the sheath.
[0045] Said axial movement of the sleeve 4 with respect to the
sheath and syringe body assembly is guided, since the teeth 49 of
the central tongues 47 of the sleeve slide in the respective longitudinal
slots 32 of the sheath. Furthermore, when the rear end 52 of the
front tongues 50 of the sleeve passes the front end of the sheath
3 the front tongues 50 converge elastically inward.
[0046] In this situation, the needle 11 is protected in the safety
position inside the sleeve 4. It should be noted that when the syringe
100 is in the safety position, any axial movement of the sleeve
4 with respect to the sheath and syringe body assembly is prevented.
In fact, the front end of the sheath 3 abuts against the rear end
52 of the front tongues 50 which are convergent and the rear abutment
surfaces 34 of the slots 32 in the sheath are in abutment against
the respective teeth 49 of the central tongues 47 of the sleeve.
[0047] It is evident that the present invention, besides referring
to the safety syringe 100 as described, also refers to a safety
kit comprising the sheath 3 the spring 6 the sleeve 4 and the
frusto conical block 22 considered as separate pieces which are
applied to a glass syringe of the known type to make it a safety
syringe.
[0048] Numerous variations and changes of detail within the reach
of a person skilled in the art can be made to the present embodiment
of the invention, without thereby departing firm the scope of the
invention as set forth in the appended claims. |