SAFETY KIT FOR PROTECTING THE NEEDLE OF A STANDARD SYRINGE, A GLASS SYRINGE OR A CARPULE
DESCRIPTION
The present invention refers to a safety kit that can be applied to a standard glass or plastic syringe, prefilled or otherwise, or to a Carpule, to turn the syringe and Carpule into a disposable safety type. For this purpose the safety kit has an automatic safety device to protect the needle of the standard syringe or Carpule once the injection has been performed.
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.
A large number of medicinal substances are packaged in Carpules or capsules. A Carpule is made up of a substantially cylindrical body, one end of which has a narrower neck which is closed by a pierceable membrane. The liquid to be injected is held in the body of the Carpule by a slidable plunger.
In order to perform the injection, the Carpule is fitted into a syringe or device suitable to receive it, and a needle which pierces the membrane of the Carpule is mounted so that operation of a stem causes the liquid to be expelled.
Because of health regulations and to avoid transmission of infectious diseases, syringes and Carpules must generally be used once and then discarded. For this reason, there is a growing market demand for disposable syringes adapted to prevent further use.
Moreover, both syringes and Carpules 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.
To overcome these drawbacks, plastic disposable syringes having safety devices to cover the needle are available on the market. These safety devices, in the form of a sleeve slidably mounted on the syringe body, generally adapt to specially dedicated syringes and not to standard syringes. That is to say, they require special syringes to be designed or existing syringes to be structurally modified, with obvious drawbacks, also and above all
from an economic point of view.
EP 1 334 740 describes a safety device for syringes, particularly pre-filled glass syringes. In the practical realization of such a device it has proved extremely problematical to achieve locking thereof in the safety position, that is with the needle covered, once the injection has been performed.
The main object of the present invention is to overcome the drawbacks encountered in the solution according to EP 1 334 740, by providing a safety kit for syringes and Carpules that ensures sure and reliable operation and secure locking of the needle covering device, once the injection has been performed.
Another object of the present invention is to provide a safety kit that is versatile and suitable to be applied to any type of standard syringe in glass or plastic, pre-filled or otherwise, Carpules and the like.
Another object of the invention is to provide such a safety kit that is able to make a standard syringe and Carpule safe and disposable and prevent accidental injury or tampering after use thereof.
Yet another object of the invention is to provide such a safety kit for a standard syringe that is inexpensive and simple to produce and assemble.
These objects are achieved according to the invention with the characteristics listed in appended independent claim 1.
Advantageous embodiments of the invention are apparent from the dependent claims.
A standard syringe comprises a syringe body hollow on the inside and open at the front and 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.
To make this syringe into a safety syringe, according to the invention, a kit is provided comprising:
- a sheath mounted fixedly on the syringe body,
- a sleeve mounted slidably on the sheath to pass from a retracted position of use in which the needle protrudes from the sleeve to perform the injection to an advanced safety position in which the needle is protected by the sleeve,
- an operating element mounted in the rear part of the stem of the plunger, and - a locking device mounted on the sleeve.
The sleeve comprises:
- first locking means cooperating with complementary locking means provided at the rear in the sheath to lock the sleeve in the retracted position of use, and - second locking means cooperating with complementary locking means provided in the front part of the sheath to lock the sleeve in the advanced safety position.
When the plunger reaches the end of the injection stroke, the operating element cooperates with the first locking means of the sleeve, to allow them to disengage and the sleeve to move from the retracted position of use to the advanced safety position.
The locking device maintains the second locking means in a position suitable to engage with the front part of the sheath, when the sleeve is in the advanced safety position, thus ensuring secure covering of the needle.
The advantages of the kit for a safety syringe according to the invention are obvious in that it allows a standard syringe to be made into a safety syringe, providing the possibility of covering the needle with the sleeve, once the injection has been performed.
The same occurs for protection of the needle of a Carpule.
Further characteristics of the invention will be apparent from the detailed description that follows, referring to purely exemplary and therefore non-limiting embodiments thereof, illustrated in the appended drawings, in which: Figure 1 is a perspective view of a standard syringe in which the elements of the safety kit according to the invention are illustrated in an exploded view;
Figure 2 is an axial sectional view illustrating two elements of the safety kit assembled and a third element exploded;
Figure 3 is an axial sectional view illustrating the three elements of the safety kit of Figure 2 assembled;
Figure 4 is a perspective view illustrating the safety kit according to the invention
assembled on the standard syringe of Figure 1, so as to form a safety syringe;
Figure 5 is an axial sectional view of the safety syringe of Figure 4 in which the standard syringe has not been sectioned;
Figure 6 is an axial sectional view of the safety syringe of Figure 4, but in the position at the end of the injection stroke; and
Figure 7 is an axial sectional view of the safety syringe of Figure 4, but in the safety position;
Figure 8 is a perspective view illustrating the safety kit according to the invention applied to a Carpule.
A safety kit according to the invention, denoted as a whole with reference numeral 1, suitable to be applied to a standard syringe 100 so as to obtain a disposable safety syringe, is described with the aid of Figures 1-7.
In this description specific reference will be made to an orientation of the syringe such that the front part corresponds to the one where the needle is disposed and the rear part to the opposite one.
With reference to Figure 1, the standard syringe 100 comprises a syringe body 101 made of plastic or glass. The syringe body 101 is substantially cylindrical in shape, is hollow on the inside and has a cylindrical chamber open at the front and rear. The syringe body 101 has at its front end a head 110 in which a needle carrier 114 which supports an injection needle 111 is mounted.
A front needle-covering cap 113 which covers the injection needle 111 is mounted in the head 110 of the syringe body. The syringe body 101 has, in its rear end, a flange 112 which protrudes radially therefrom to facilitate gripping by the user.
A plunger 102 made of rubber can slide axially with a tight seal in the cylindrical chamber of the syringe body 101. The plunger 102 is supported at the front end by a stem 120 made of plastic. The stem 120 has, at its rear end, a disc-shaped flange 121 disposed outside the syringe body 101 to able to be operated manually by the user.
The safety kit 1 comprises a rear cap or operating element or opening cone 2, a sheath 3, a spring 4, a needle-covering sleeve 5 and a locking device 7. The rear cap or opening cone 2 is applied on the rear flange 121 of the stem 120. The sheath 3 is mounted on the
syringe body 101. The sleeve 5 is mounted on the sheath 3 with the spring 4 interposed therebetween. The locking device 7 is applied on the sleeve 5.
The rear cap 2 has a cylindrical body 20 hollow on the inside and open at the front to receive the disc-shaped flange 121 of the plunger stem. Four flexible tongues 21 arranged in diametrically opposite positions and protruding inward are formed in the body 20 of the rear cap. In this manner, as shown in Figure 5, when the rear cap 2 is applied to the disc-shaped flange 121, the tongues 21 bend outwards through the action of the flange 121 and return elastically to the initial position so as to lock the cap 2 to the flange 121.
The rear cap 2 has a frustoconical or tapered crown 22 at the front which defines a flat, annular front abutment surface 23.
The sheath 3 has a substantially cylindrical body open at the front and rear and having an inside diameter substantially equal to or slightly greater than the outside diameter of the syringe body 101 so as to be able to be force fitted thereon. The sheath 3, at its rear end, comprises a collar 30 which protrudes radially outward so as to define an annular abutment surface 35 (Figure 2).
Two teeth 31 which protrude radially outward in diametrically opposite positions 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, aligned with the teeth 31. As shown also in Figure 2, each longitudinal slot 32 defines a rear abutment surface 33 and a front abutment surface 34 situated at the end of a tapering or bevel 134.
The sheath 3 has at the front, in its inside surface, longitudinal ribs 135 protruding inwards to elastically grip the syringe body 101, when the sheath 3 is forced thereon, so as to firmly lock the sheath 3 on the syringe body 101. As shown in Figure 5, the sheath 3 is forced onto the syringe body 101 until the rear edge of the collar 30 abuts against the flange 112 of the syringe body.
The spring 4 is a helicoidal compression spring which is fitted over the sheath 3 so that its front end abuts against the abutment surface 35 of the collar 30 of the sheath.
The sleeve 5 is substantially cylindrical in shape, hollow on the inside and open at the front and rear. The sleeve 5 has an inside diameter slightly greater than the outside
diameter of the sheath 3 so that it can be fitted slidably thereon.
The sleeve 5 has a cylindrical rear part 50 with a larger diameter and a cylindrical front part 51 with a smaller diameter. As shown in Figure 2, the rear cylindrical part 50 with a larger diameter defines on the inside an annular abutment surface 52 able to abut against the front end of the spring 4. On the other hand, the front part 51 with a smaller diameter defines on the inside an annular abutment surface 62 able to abut against the front edge of the sheath 3.
In this manner, as shown in Figure 2, the helicoidal compression spring 4 wound 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 52 of the sleeve 5.
As shown better in Figure 1, two rear tongues 53 are formed in the side wall of the part 50 of the sleeve with the larger diameter. The rear tongues 53 are disposed longitudinally in diametrically opposite positions and are flexible. Each rear tongue 53 has a rectangular slot 54 within which the respective tooth 31 of the collar 30 of the sheath snap engages, so as to firmly retain the sleeve 5 on the sheath 3 against the pushing action of the spring 4.
Each rear tongue 53 is defined by two parallel longitudinal notches 55, which reach the end of the part with the larger diameter 50. In this manner each rear tongue 53 can bend radially outward. Furthermore, each rear tongue 53 has a rear part which protrudes beyond the rear end of the part 50 with the larger diameter. The rear end of each tongue 53 has a tapered surface 56 able to cooperate with the tapered surface 22 of the rear cap 2.
At the rear end of the part with the greater diameter 50, a flange 65 protrudes radially to facilitate gripping by the user. The rear flange 65 of the sleeve is not present in the area where the rear tongues 53 are situated so as not to interfere with them. The flange 65 of the sleeve has in its rear wall an annular abutment surface against which the rear abutment flange 112 of the syringe body 101 abuts.
In the side wall of the body of the sleeve 5 two central tongues 57 are formed. The central tongues 57 are disposed longitudinally in diametrically opposite positions and are flexible. Each central tongue 57 is defined by a substantially U-shaped notch 58, so as to be able to bend elastically. The U-shaped notch 58 has at the front a rectangular seat 69.
Each central tongue 57 has an outward protruding tooth 59.
Again in the side wall of the body of the sleeve 3 two front tongues 60 are formed. The front tongues 60 are disposed longitudinally in diametrically opposite positions. Each front tongue 60 is defined by a substantially U-shaped notch 61, so as to be able to bend elastically. On the outside surface of the front tongues there are respective protrusions or teeth 65 which protrude outward.
The central tongues 57 are opposed to the front tongues 60. Each central tongue 57 has an end surface 66 opposed to the end surface 67 of the respective front tongue 60.
The locking device 7 is in the form of a cylindrical sleeve hollow on the inside, open at the front and rear and having an inside diameter slightly greater than the outside diameter of the body of the sleeve 5. The locking device 7 has two flexible circumferential tongues 70 formed by means of two U-shaped notches 71 on the side wall of the locking cylinder 7, and two longitudinal tongues 170 formed by means of respective pairs of longitudinal notches 171.
On the inside surface of the tongues 70 respective teeth 72 having a tapered surface 73 which defines a radial abutment surface 74 are provided (Figure 2).
When the locking device 7 is fitted on the sleeve 5, the inner surface of the locking device cooperates with the protrusions 68 and 59 respectively of the front tongues 60 and central tongues 57. hi particular the longitudinal flexible tongues 170 of the locking device 7 act on the protrusions 68 of the front tongues 60. hi this manner the front tongues 60 and the central tongues 57 bend elastically inward so that their ends 67 and 66 enter the longitudinal slots 32 of the sheath 3 (Figure 5).
When the rear end edge of the safety device 7 goes into abutment against the part with the larger diameter 50 of the sleeve 5, each tooth 71 of the circumferential tongues 70 of the safety device goes beyond the portion of wall which divides the front tongues 60 from the central tongues 57 of the sleeve 5 and settles into the seat 69 of U-shaped notch 58 of the central tongue 57. In this situation, as shown in Figure 3, the locking device 7 cannot be removed from the sleeve 5, because the abutment surface 74 of the teeth 72 of the circumferential tongues of the safety device is in abutment against the wall of the seat 69
of the sleeve 5. Thus the locking device 7 remains locked in position on the sleeve 5 maintaining the front tongues 60 and the central tongues 57 bent inward.
At this point, as shown in Figures 4 and 5, the safety kit is assembled on the standard syringe 100 so as to form a safety syringe ready for use.
Operation of the safety syringe according to the invention will now be described.
With reference to Figures 4 e 5, in an initial condition the spring 4 is compressed between the annular abutment surface 35 of the collar 30 of the sheath 3 and the annular abutment surface 52 of the sleeve 5. The teeth 31 of the collar of the sheath 3 are engaged in the slots 54 of the rear tongues 53 of the sleeve, avoiding any axial movement of the sheath 3 and the syringe body 101 assembly with respect to the sleeve 5. Furthermore, the locking device 7 maintains the front and central tongues 60 and 57 bent inward in the longitudinal slots 32 of the sheath 3.
The chamber of the syringe body 101 is filled or is pre-filled with a solution for injection. Thus, when the injection is performed and the plunger 102 reaches the end of its stroke in the chamber of the syringe body 101, as shown in Figure 6, the tapered surface 22 of the rear cap 2 cooperates with the tapered surface 56 of the rear end of the rear tongues 53 of the sleeve 5 causing inward radial bending thereof.
Consequently the teeth 31 of the collar of the sheath 3 disengage from the slots 54 of the tongues 53 and the sleeve 5 is no longer firmly constrained to the sheath 3 and syringe body 101 assembly. As a result, as shown in Figure 7, the spring 6, which was compressed, is released, lengthening, pushing the sleeve 5 and causing forward axial sliding thereof with respect to the sheath integral with the syringe body, until the front tongues 60 of the sleeve 5 pass the front end of the sheath 3, and the abutment surface 66 of the central tongues 57 abuts against the front abutment surface 34 of the longitudinal slots 32 of the sheath.
Passing of the front end of the sheath 3 by the tongues 60 is made possible by bevels 134 provided in the sheath 3, which form an invitation for sliding of the tongues 60, and to the simultaneous, temporary yielding of the tongues 60 of the sleeve 5 and of the longitudinal flexible tongues 170 of the locking device 7.
Said axial movement of the sleeve 5 with respect to the sheath assembly integral with the syringe body is guided, since the front tongues 60 and the central tongues 57 of the sleeve slide in the respective longitudinal slots 32 of the sheath.
hi this situation, the needle 111 is protected in the safety position inside the sleeve 5. It should be noted that when the sleeve 5 is in the safety position, any axial movement of the sleeve 5 with respect to the sheath 3 and syringe body assembly is prevented, hi fact the front end of the sheath 3 abuts against the rear end 67 of the front tongues 60, which are again bent inward, and the front abutment surfaces 34 of the longitudinal slots 32 of the sheath abut against the front abutment surfaces 66 of the tongues 57, also bent inward.
This has been achieved in a simple and inexpensive manner thanks to the use of the locking device 7, tubular in shape, which, when fitted over the sleeve, acts on the tongues 60, 57, keeping them constantly bent toward the inside of the longitudinal slots 32 of the sheath 3.
The present embodiment of the invention has been described with specific reference to a standard syringe 100. However, the safety kit 1 can also be applied to a Carpule 201, as illustrated in Figure 8.
The Carpule 201 comprises a vial or capsule made of plastic or glass. The body of the Carpule 201 is substantially cylindrical in shape, is hollow on the inside and has a cylindrical chamber designed to contain the medicinal solution for injection. The Carpule body 201 has at its front end a smaller-diameter neck and a head 210, provided with a stopper or tight, pierceable membrane. The Carpule 201 is provided with an injection needle 211 provided with two tips 213, 213' at its ends. The needle 211 is supported by a needle-holder 214.
The tip 213' pierces the membrane 210 of the head of the Carpule to come into contact with the medicinal solution inside the Carpule and the needle-holder 214 is locked tightly in the cap of the head 210 of the Carpule. Clearly the needle-holder 214 can be mounted integrally with the head 210 of the Carpule.
A plunger 202, generally made of rubber, is tightly mounted slidably inside the rear part of the carpule 201. A seat 203 able to receive a protrusion 204 formed in the front end of
a stem 220 is provided in the rear part of the plunger 202.
The stem 220 has at its rear end an opening cone 2, like that previously described with reference to the syringe 100, which serves to operate the safety mechanism of the kit. The opening cone 2 can be made in a single body with the stem 220, as illustrated in Figure 8, or can be a separate element forming part of the safety kit 1 and be mounted on the rear flange of the stem 220.
The protrusion 204 of the stem couples in a screwing or snap fastening engagement inside the seat 203 of the plunger 202. Clearly the plunger 202 can already be made integral with the front end of the stem 220. In fact the Carpule 201 can be pre-filled or empty.
To make the Carpule 201 safe it is inserted inside the sheath 3, so that the longitudinal ribs 135 of the sheath grip on the head 210 of the Carpule to lock it firmly inside the sheath 3 and make it integral therewith. Then, as described previously, the spring 4 and the sheath 3 are inserted inside the sleeve 5 and the locking device 7 is applied to the sleeve 5. In this manner the Carpule 201 is made like an automatic safety syringe.
The needle 211 can be mounted in the head of the Carpule before or after insertion of the Carpule 201 inside the sheath 3. Alternatively, the needle-carrier 214 can be mounted integrally in the head of the sheath 3, so that when the Carpule 201 is inserted into the sleeve 3, the membrane of its head is pierced by the second tip 213' of the needle.
Numerous variations and modifications of detail within the reach of a person skilled in the art can be made to the present embodiment of the invention and in any case come within the scope of the invention as set forth in the appended claims.