HK1055565B - Device for separating a hypodermic needle from an injection instrument - Google Patents

Description

Device for separating injection needle from syringe

Technical Field

The invention relates to a device for separating the connecting end of a hypodermic needle from the end of a syringe, said connecting end of the needle having connecting parts complementary to the connecting parts on the end of the syringe, one of said connecting parts having a radial elastic force, and means for converting an axial force applied between the needle and the syringe into at least one radial component capable of deforming said elastic connecting part.

Background

Hypodermic needles of the type that are commercially available are relatively easy and quick to secure to the end of the syringe because it is no longer necessary to twist the needle, and pressure along the axis is sufficient to engage the complementary connecting portions. Theoretically, it should also be possible to separate them with a withdrawal force along the axis, but this operation is difficult because there is no suitable force part for the withdrawal, so that they can only be separated by unscrewing in a conventional manner.

Given that in the case of chronic conditions requiring daily injections of medication, patients must frequently self-inject, the need for handling injection needles should be readily met, especially for the purpose of facilitating their safe removal, disposal or storage.

Publication WO92/13585 (1992, 8/20) of the world intellectual property organization describes a needle container comprising a conical housing, the needle being held by friction at the open end of the conical housing by the user prior to use. After use, the user may reinsert the needle into the conical housing, pushing the needle under the resilient tabs at the open end of the conical housing. After the needle is fully inserted, the resilient tabs snap back to prevent withdrawal of the needle.

EP0364839 discloses a medical injector of the single use type provided with a hollow cap which can be superimposed on the needle after the injection has been carried out to protect the needle. A portion is provided adjacent the opening of the cap cavity that can tightly engage the fitting when the needle is forced into the cap cavity.

In all the prior art cases, when the needle is fixed to the outlet end of the syringe, the user is no longer able to prevent the needle from being injured. Several injection devices have been proposed to overcome this drawback, and for this purpose they comprise a mechanism for performing the injection, which is movable by a pick-up device moving against a spring force into a raised position, from which it can be released to perform the injection process, i.e. act on the plunger containing the liquid to be injected.

Devices of the above type are disclosed, for example, in european patent No. EP 0359761. The housing of such a device is close to a large-sized fountain pen, and the injection needle is always left inside the housing when no injection is performed. The injection device has a mechanism for performing an injection operation, which mechanism can be pushed by a pick-up unit against the force of a spring into a raised position from which it can be released to perform the injection process. The mechanism moves the hypodermic needle axially so that the needle projects from the forward end of the housing of the device into contact with the patient's skin so that it can be inserted through the skin to inject fluid into the body.

With such a device, the injection needle is located inside the cylindrical sleeve of the injection device except during the injection operation, so that the user cannot see the exact position of the injection needle to be introduced into the opening of the housing, where it has to be separated from the injection device, since the injection needle cannot be seen through the cylindrical sleeve of the injection device.

The object of the invention is to make the handling of used injection needles easier.

Disclosure of Invention

To this end, the invention relates to a separation device for separating the connecting end of a hypodermic needle from the end of a syringe.

The advantage of this device is its simplicity in design and use. Other advantages are the speed of the operation required to remove the needle and the possibility of not making any contact with it after it has been separated from the syringe.

Other advantages and characteristics of the invention will become apparent from the following description, which, taken in conjunction with the annexed schematic drawings, illustrates an embodiment of the invention and some variants of the several containers of the invention.

Drawings

FIGS. 1a and 1b are vertical cross-sectional views of one embodiment of the device, illustrating two steps in the process of withdrawing a hypodermic needle;

FIG. 2 is a vertical cross-sectional view of a first variation;

figures 3a, 3b, 3c are vertical cross-sectional views of a second variant, showing three successive steps in the use of a hypodermic needle;

fig. 4a, 4b, 4c are cross-sectional views of a third variant showing three sequential steps in the use of a hypodermic needle.

Detailed Description

A hypodermic needle 2 is integrated with a connecting end in the form of a hollow socket 2a, the inner surface of which has a connecting portion consisting of at least one rib. The hollow sleeve 2a is preferably made of a material which is elastically deformable so that it can expand elastically and engage the rib with a complementary connection, such as a rib, a groove, a thread 3a, placed on the outer surface of the end portion 3 of the syringe 4. As shown in fig. 1, it is evident that the semi-circular profile of the rib makes it possible to convert an axial pressure in both directions into a radial component capable of elastically deforming the hollow seat 2 a.

In the examples illustrated herein, the syringe 4 resembles a ballpoint pen in the following respects: it has a cylindrical barrel 5 which houses or houses a cartridge 6, the cartridge 6 being intended to contain a dose of medicament to be injected, the front end of the syringe terminating in a connecting end 3 which is a hollow hub 2a for pushing in a hypodermic needle 2. The syringe 4 is of a known type, for example of the type disclosed in US5,092,842 and US5,114,406 or in EP0359761, in which the hypodermic needle is retractable within the cylindrical barrel 5 in its rest state. Since such a device does not form part of the present invention, the rest of its structure and operation will not be described in more detail.

The separating device 10 shown in fig. 1a, 1b for separating the connecting end 2a of the hypodermic needle 2 from the end 3 of the syringe 4 takes the form of a cylindrical container consisting of two concentric walls, a guiding outer wall 10a and an inner wall formed by a number of resilient arms 10 b. The guide outer wall 10a and the elastic arms 10b are formed as a single body with a flat loop portion 10 c. The free ends of the resilient arms 10b terminate in locking units 13 which extend towards the inner surface of these resilient arms 10b, thereby forming a variable diameter opening 17. The edge of this opening 17 is defined by the angled face 13a of the locking unit 13.

The beveled surface 13a has the following functions: when the used hypodermic needle 2 is introduced slidingly inside the inner surface of the outer cylindrical surface 10a of the extraction device 10, guided by the cylindrical surface 5 of the barrel of the syringe 4 against the bevel 13a (which inner surface acts as a guide surface for the cylindrical surface 5), and when a downward axial pressure is applied, the needle generates a centrifugal radial component force which allows the resilient arms 10b to disengage, as shown in fig. 1a, thereby increasing the diameter of the opening 17 until it allows the connecting tip 2a of the hypodermic needle 2 to be inserted through the opening 17.

As soon as the upper surface of the connection end 2a is below the level of the locking unit 13, the resilient arm 10b returns to its original position, as shown in fig. 1 b. The syringe 4 can then be separated from the hypodermic needle 2 if a withdrawal force is exerted on the syringe 4 while the withdrawal means 10 holding the hypodermic needle 2 is secured.

Fig. 2 shows a part of a combination device which, in addition to the variants 11-11e of the device for withdrawing a needle 2 of fig. 1a and 1b, also has a container 1-1e for storing a sterile hypodermic needle 2.

Such a storage container 1-1e has a housing 1 defined by a cylindrical wall 1b and intended to receive a hypodermic needle 2. The diameter of the cylindrical wall 1b of the housing 1 of the hypodermic needle 2 is calculated to allow fitting of an intermediate portion between the hub 2a and the needle 2, so that the needle 2 can be correctly positioned. The upper edge 1a of the cylindrical wall 1b acts as a stop for the length of movement provided between the seat 2a and the intermediate portion 2c of the injection needle 2. A second cylindrical wall 1c, coaxial with the cylindrical wall 1b of the housing 1 for the injection needle 2, surrounds the cylindrical wall 1b until it reaches the base of the housing 1 defined by the cylindrical wall 1 b. This wall radial portion 1d extends outwardly and terminates in a third cylindrical wall 1e, which wall 1e is concentric with the other two walls 1c, but extends rearwardly higher than the other two walls and forms an access opening 7.

The general outline of the so-called extraction means 11-11e is generally similar to the outline of the container 1-1e intended to house the sterile injection needle 2. It also has a housing 11 to accommodate an injection needle 2. This housing 11 is identical to the housing 1 and terminates at its upper end in a rim 11a on which rests the outer surface of the housing forming the connecting end 2a of the injection needle 2. In this extraction device, the second cylindrical wall 11c surrounding the wall forming the housing 11 continues upwards to the upper end (plane) of the outer wall 11e by means of a plurality of resilient arms 12 which combine to form a cylindrical receptacle whose diameter matches that of the connecting end 2a of the hypodermic needle 2.

These resilient arms 12, which function in the same way as the resilient arms 10b in fig. 1a, 1b, also terminate in locking units 13, which locking units 13 project inwardly into the receptacles formed between the resilient arms 12 and delimit a variable-diameter opening 17. The length of the resilient arms 12 is chosen such that when the lower surface of the connecting end 2a rests against the edge 11a, the lower or inner surface of the locking element 13 is located exactly on the upper or outer surface of the connecting end 2a of the injection needle 2. The upper or outer surface 13a of these locking elements 13 is beveled and functions as in the previous embodiment, and therefore an equivalent description of the method of operation of the previous embodiment is provided for reference.

The upper edge of the storage container 1-1e for the sterile (non-toxic) injection needle 2 and the upper edge of the outer wall 11e of the extraction device 11-11e are connected to each other by a horizontal wall 1 f. Preferably, this wall 1f allows to connect the container 1-1e and the extraction device 11-11e to pairs of other containers and extraction devices of the same type for storage.

In this variant, the injection needle remains clamped in the housing 11 when it is detached from the syringe 4, so that it is protected from any contact.

In the variant depicted in fig. 2, each needle requires two distinct containers 1-1e and 11-11e, one for sterilizing the needle 2 and the other for the needle 2 after use. In the following, we will describe with reference to figures 3 to 3c another variant of the invention in which a single container can in turn house a sterile needle, and then allow withdrawal and storage of the used needle, thus doubling the capacity of the single mounting of the needle compared to the previous embodiments.

In the above-described variant, there is a container 21-21e, which is more or less similar to the previous one, having three concentric cylindrical walls 21b, 21c, 21e, but of these three cylindrical walls, the housing 21 formed by the cylindrical wall 21b does not directly house the hypodermic needle 2, but houses a further receptacle portion 22, this receptacle 22 being formed by two coaxial cylindrical portions, a lower receptacle portion 22a, housed and fixed in the wall 21b of the housing 21, and an upper receptacle portion 22b, which extends as far as the upper end of the outer cylindrical surface 21e of the container 21-21e and is itself divided into two parts by an opening 28 formed by a locking unit 23 (fig. 3 b).

The height of the upper part of the receptacle 22 above the housing 21 in which the needle 2 is arranged is approximately twice the height of the connecting end 2a of the hypodermic needle 2. The resilient arms 22c are disposed at the lower portion of the upper cylindrical wall 22b of the receptacle 22. These resilient arms 22c have a structure similar to the resilient arms 12 of fig. 2. Their upper ends also terminate in a locking unit 23 which is identical to the locking unit 13 in the preceding figures and which functions identically to the locking unit 13.

Fig. 3a shows a ring 24 having a channel 24a at its bottom and surrounding the connecting end 2a of the injection needle 2. This ring 24a is dimensioned so that it projects slightly beyond the upper surface of the connecting end 2a of the injection needle 2, so that the locking element 23 and the resilient arms 22c remain behind, as shown in fig. 3 a. The diameter of the ring 24 can be selected such that it grips the connection end 2a by friction. A lid 25, which may be perforated, closes the upper opening of the containers 21-21 e.

When the user wishes to connect the needle 2 housed in this container 21-21e to the end 3 of the syringe 4, he places the lower edge of the cylindrical wall 5 of the barrel of the syringe 4 in the centre of the cover 25 and then exerts an axial pressure on the syringe 4. The first effect of the above-mentioned pressure is to penetrate the cap 25 and then, guided by the cylindrical wall 21e of the container 21-21e, the syringe 4 introduces the end 3 of the syringe 4 into the cavity forming the housing of the connecting tip 2a of the hypodermic needle 2. The connection between the injection needle 2 and the outer wall of the sleeve is made by exerting an axial pressure on the syringe 4 sufficient to reach the deformation of the rib 2b on the inner surface of the sleeve, so that it locks onto the groove or thread 3a at the end 3 of the syringe 4.

If the needle 2 connected to the end 3 is withdrawn along the axis, it rises with the ring 24 until it abuts against the edge 22d of the access opening 27 in the withdrawal means, which is thus formed at the upper end of the cylindrical wall 22b of the receptacle 22. The diameter of the access opening 27 is about the same as the diameter of the connecting end 2a of the injection needle 2, thus allowing the injection needle to freely enter or withdraw from the container 21-21e by sliding movement between the connecting end 2a and the ring 24. It is clear that the friction between the two parts must be less than the axial withdrawal force that must be exerted between the needle 2 and the syringe 4 in order to separate the needle 2 and the syringe 4.

At the end of the movement of the collar 24, as shown in fig. 3b, channels 24a are opposite the locking elements 23, allowing the elasticity of the locking element elastic arms 22c to return to their original shape to pass them and allowing the locking elements 23 to protrude from the inner surface of the collar 24.

Once the sterile needle 2 has been removed from the container in the manner described, the container is ready to receive a used needle and to separate the needle from the syringe 4. The used needle 2 is then inserted into the extraction device through the access opening 27 and it can be seen that the separation method is the same as that described in relation to figure 2. The portions of the locking element 23 projecting inside the ring 24 have inclined upper surfaces 23a, so that, when the connecting end 2a of the needle 2 is inserted, the axial pressure exerted on the central inclined surfaces forces them apart, so that the connecting end can be pushed until it abuts against the edge 21a formed at the upper end of the housing 21 of the needle 2.

At this point, the locking unit 23 is released and can thus close again on the upper end of the connecting end 2a of the needle 2, trapping the needle in the container 21-21 e. The syringe 4 can then be separated by exerting a withdrawal force along its axis and holding the containers 21-21e, the ergonomic shape of which constitutes an engagement surface (relationship) making it easy to grasp or hold, otherwise this withdrawal operation would be difficult, if not impossible, for an inexperienced user. The advantage of such an ergonomic interface is further increased when several containers are arranged side by side and connected together by a common horizontal wall 1f, which will improve the holding force of the common shared mounting supporting these containers 21-21 e.

In the variant of the invention illustrated in fig. 4a to 4c, the container takes the form of a tubular body 31 which forms a cylindrical housing 36 which enters and exits through an opening 38. The hypodermic needles may be inserted sequentially into the housing 36. In this embodiment, the coupling sleeve 2a of the needle 2 also acts as a spacer which keeps the needles 2 separated from each other along their axes. Since the coupling socket 2a must expand radially when it is connected to the end 3 of the syringe 4, the external diameter of the coupling socket 2a is slightly smaller than the internal diameter of the tubular body 31, so as to prevent the connection operation from causing the needle to jam in the tubular body 31, making it difficult to move. The injection needle may be held in the tubular body 31 by a further portion 2d located between the coupling sleeve 2a and the injection needle 2, the diameter of which should match the inner diameter of the tubular body 31.

The way in which the needle 2 is accessible from one end of the tubular body 31 and is connected to the end 3 of the syringe is the same as that described above. In this embodiment, the number of needles 2 housed in the tubular body is six. The first needle 2, which is to be used last, is held in position by a support 32 arranged to slide in the tubular body 31. However, the friction between the support 32 and the inner wall of the tubular body 31 is chosen so that it will withstand the pressure required to achieve the connection between the needle 2 and the syringe. The support 32 has two axial housings 32a, 32b, which are arranged mirror-symmetrically with respect to the center of the support 32 and open at their outward facing ends. The diameters of the housings are selectable to accommodate the intermediate portion 2c of the hypodermic needle 2.

This support 32 and the axial housings 32a, 32b allow the needle 2 withdrawn from the tubular body 31 to be inserted through the other end of the tubular body 31 and then separated from the injection device 4 after use. For this purpose, the other end has a resilient arm 33, which resilient arm 33 terminates at its end in a locking unit 34 as in the above-described embodiment. These locking units 34 have inclined outer surfaces 34a which form the boundaries of the variable diameter opening 37. These inclined surfaces 34a are intended to convert the axial force exerted thereon by the portion 2d of the needle 2 into a radial component to bend the elastic arms 33 so as to increase the diameter of the opening 37 to allow the passage of the connecting tip 2 a. The support 32 must slide each time a used needle is inserted through the end of the tubular member 31 having the locking unit 34.

As shown in fig. 4c, the locking elements 34 engage in the space between the end of the coupling sleeve 2a and the sleeve 6, so that the extraction force exerted between the syringe 4 and the tubular body 31 allows the syringe 4 and the needle 2 to be separated, the needle 2 being trapped in the tubular body 31. The ergonomic shape of the tubular body allows a good grip and therefore an easy handling.

Claims (5)

1. A device for separating a needle (2) from a syringe (4), the connecting end (2a) of the hypodermic needle (2) having connecting portions complementary to the connecting portions (3a) on said end (3), one of said connecting portions being radially elastic and having means for converting an axial force applied between the needle (2) and said syringe (4) into at least one radial component capable of deforming said elastic connecting portion, the device comprising an opening (17, 28, 37) defined by a locking unit (13, 23, 34) formed in one piece from elastic tabs (10b, 12, 22c, 33) so as to have a diameter which can vary between a maximum diameter and a minimum diameter, i.e. a diameter which is at least equal to the diameter of said connecting end (2a) and at least one piece (13a ) associated with the locking unit (13, 23, 34), 23a, 34a) for converting an axial force exerted on said single piece (13a, 23a, 34a) into at least one radial component which can be applied to said resilient flaps (10b, 12, 22c, 33) to deform them radially so as to increase the diameter of said openings (17, 28, 37) when said connecting tip (2a) is moved axially together with the injection needle (2) forward through said openings (17, 28, 37) and to recover their original diameter after said connecting tip (2a) has passed through the openings and the locking unit (13, 23, 34) has been brought into engagement with the rear surface of said connecting tip (2a), wherein the device has a guide surface (10a, 11e) coaxial with said openings (17, 28, 37).

2. Separating device according to claim 1, wherein the opening (17, 28, 37) serves as an access opening in the closing housing (11, 21, 32 b).

3. Separating device according to claim 1, wherein one edge of the guide surface (10a, 11e) is connected to the storage container (1-1e) of the at least one hypodermic needle (2) by means of a horizontal surface (1 f).

4. Separating device according to any one of the preceding claims, wherein the device has a longitudinally bifurcated cylindrical casing (22) of approximately equal length so as to be able to match the length of said connecting end (2a) through said opening (28) defined by said locking unit (23) formed in one piece by a resilient arm (22c) connected to one end of said cylindrical casing (22), said cylindrical casing (22) communicating externally at its other end through an access opening (27) of diameter approximately equal to the diameter of the connecting end (2a) of said hypodermic needle (2), and a ring (24) of inner diameter approximately equal to the inner diameter of said access opening (27) and arranged so as to be slidable inside said cylindrical casing (22) so as to be able to occupy two defined positions inside the casing, in one of the two positions, the ring is adjacent to said opening (27), the ring also having a passage (24a) arranged and dimensioned so as to allow said locking unit (23) to protrude beyond the inner surface of the ring (24) when the ring is adjacent to said opening (27), and in its other defined position, the ring retains the locking unit (23) formed as a single piece by said resilient arms (22c) behind the connecting end (2a), the ring being frictionally secured to the connecting end (2 a).

5. Separating device according to claim 4, wherein the device has the shape of a tubular body in which several hypodermic needles (2) are arranged in sequence in respective positions so that said syringe (4) is accessible from one end of said wall (31), while the other end has said radially elastic locking unit (33, 34) to allow its diameter to vary between a maximum diameter and a minimum diameter, i.e. at least equal to the diameter of said connecting tip (2a) and at least of a single piece (34a) associated with the locking unit, so as to convert an axial force exerted on said single piece into at least one radial component capable of being exerted on said locking unit (33, 34) so as to deform them radially to increase the diameter of said opening.