Patent Description:
Medical devices provided with sharp pointed needles are of daily practice among the medical community in order to perform injections into or to take samples from tissues, veins or arteries of the patient. Medical devices having needles may comprise, but not be limited to, injection devices such as syringes, pen-injectors, catheters or blood collection devices. Sharp pointed needles of these medical devices present an inherent risk of needle stick injury to the medical staff and/or the patients and are thus usually covered by a protective cap before use. This cap can preserve the needle not only from contamination but also from undesired contacts or punctures that could occur during transport and delivery of the medical devices. Obviously, such a cap needs to be removed immediately before use of the medical device. Also, the needle needs to be protected after use of the medical device in order to prevent accidental needle sticks.

<CIT>discloses a safety device which comprises a protective cap and a shield to be mounted on a tip of a syringe. The safety device is attached to the syringe tip by means of a mounting ring which is to be clipped on a bump formed on the syringe tip.

However, the proposed structure is relatively weak against axial force that may be applied to the safety assembly and under some circumstance the ring may be easily pulled out from the syringe tip.

Also, the medical device is typically sterilized only after the mounting ring is assembled with the syringe, and as a result the reliability of clipping between the syringe tip and the mounting ring is limited. Document <CIT> describes a tamperproof device allowing to seal the medical container before use.

In view of the above, an object of the present invention is to improve reliability of the connection between a safety device and a medical container, thereby reducing a risk of the safety device being pulled out and unintentional exposure of a needle of the medical device.

A first aspect of the invention concerns a safety assembly for preventing needle stick injury with a needle, the needle having a proximal end fixed to a tip of a medical container and a pointed distal end, the safety assembly comprising:.

The sleeve portion of the outer ring prevents radial movement of the snap feature of the inner ring. Since the radial movement of the snap feature is required to detach the inner ring from the tip of the medical container, this configuration prevents the inner ring from being pulled out of the container tip by accident. This configuration increases reliability of the connection between the medical container and the attachment ring, and then between the medical container and the safety assembly. As a matter of fact, the outer ring and the inner ring may be chosen to have the same thermal expansion, and consequently, the outer ring enables to maintain the inner ring on the container's tip, even after the sterilization process.

According to one embodiment, the inner ring comprises a distal ring and one mounting finger extending proximally from the distal ring, the snap feature being formed at a proximal end of said mounting finger, the mounting finger being able to be deformed radially outwardly, the outer ring being fixed on the inner ring such that the sleeve portion surrounds the at least one mounting finger to prevent radial deformation of the at least one mounting finger. The inner ring is configured to be inserted axially on the container's tip. During axial insertion of the inner ring on the tip of the container, the mounting fingers are flexed outwardly so that the snap feature may engage the complementary snap feature of the container. Once the snap feature engages the complementary snap feature of the container, the inner ring is maintained in this position by the outer ring which prevents radial deformation of the mounting fingers. More precisely, the sleeve portion prevents the mounting fingers to be flexed outwardly and consequently they prevent radial movement of the snap feature. As long as the snap feature cannot move radially, they cannot disengage the complementary snap feature, such that the attachment ring cannot move axially. The inner ring is then maintained snapped on the container's tip by the outer ring. The attachment ring enables then a more secure attachment between the safety device and the container.

According to another embodiment, the inner ring comprises two half rings having each an inner face provided with at least a snap feature, the two half rings being configured to be interlocked around the tip of the container such that the snap features engage complementary snap features on the tip of the container in order to prevent axial movement of the inner ring with respect to the container, the sleeve portion of the outer ring being configured to surround the two half rings to prevent radial movement of the two half rings.

According to this embodiment, the two half rings are assembled around the container's tip and then maintained together by the outer ring. The snap features are maintained engaged with the complementary snap feature as long as they cannot move radially, such that the safety device cannot be pulled out from the container's tip.

Advantageously, the two half rings may be identical, each half ring comprising first and second hook portions arranged such that the first and second hook portions of one half ring respectively engage the second and first hook portions of the other half ring. According to this embodiment, since the two half rings have the identical design, the cost for producing the half rings and therefore the safety assembly can be reduced. The half rings have hook portions for engaging with each other and no additional fixing means will be required. This can further reduce the cost for producing the safety assembly.

Advantageously, the two half rings may be connected by a hinge. According to this embodiment, the two half rings are configured to pivot around the hinge. According to this embodiment, the two half rings can pivot around the hinge between an engaged position in which the half rings are engaged with each other and a disengaged position in which the half rings are disengaged from each other. This can facilitate the process for assembling the inner ring with the medical container.

Advantageously, the outer ring is snapped on the inner ring.

More precisely, the outer ring preferably comprises at least a clipping feature clipped into a complementary clipping feature of the inner ring. This embodiment provides an easy and secure way to maintain the outer ring around the inner ring.

According to one embodiment, the inner ring may have a flange extending radially outwardly, and the outer ring may have at least one locking finger extending proximally and having a proximal end extending radially inwardly, the proximal end of the at least one locking finger being engaged with the flange of the inner ring to interlock the outer ring with the inner ring. According to this embodiment, the locking finger(s) of the outer ring engage(s) with the flange of the inner ring. It is ensured that the outer ring cannot be pulled out from the inner ring.

Advantageously, the flange of the inner ring may comprise a proximal wall inclined relative to a plane which extends perpendicular to a central axis of the inner ring, in order to ease manufacturing of the inner ring.

According to this embodiment, the flange of the inner ring is delimited by an inclined wall. This increases pull-out force required to pull the outer ring from the inner ring and ensures that the attachment ring cannot be removed easily by accident.

According to one embodiment, the outer ring has an inner protrusion extending radially inwardly and being configured to frictionally engage the tip of the container. According to this embodiment, the inner protrusion of the outer ring is frictionally engaged with the tip of the container when the safety assembly is attached to the medical container. Therefore, rotational torque which may be applied on the outer ring is prevented from being transmitted to the inner ring.

Advantageously, the inner ring and the outer ring are made of a material having the same thermal expansion. It enables a better attachment of the attachment ring to the container's tip after sterilization process.

Advantageously, the inner ring and the outer ring are made of plastic.

According to a preferred embodiment, the safety device comprises:.

Advantageously, the protective cap is configured to be removed from the tip of the container by axial movement in a distal direction.

Advantageously, the protective arm comprises a proximal extremity provided with a cam surface, the protective cap comprising a proximal extremity provided with an engaging peg, the cam surface and the engaging peg being arranged so that, when the safety assembly is mounted around the tip of the container, removing the protective cap from the tip by a distal movement displaces the protective arm from the storage position to the retracted position.

A second aspect of the invention concerns a medical device comprising:.

According to one embodiment, the complementary snap feature may be a bump, the snap feature comprising a groove delimited proximally by an inwardly protruding protrusion configured to be inserted proximally from the bump.

According to another embodiment, the complementary snap feature may be a groove, the snap feature comprising an inwardly protruding protrusion configured to be inserted into the groove.

Advantageously, the container is made of glass.

Embodiments of the present invention will be hereinafter described by way of example, with reference to the accompanying figures, in which:.

In this application, the distal end of a component or apparatus should be understood as meaning the end farthest from the hand of the user and the proximal end must be understood as meaning the end closest to the hand of the user. As such, the distal direction should be understood as the direction farther away from the hand of the user, and the proximal direction is the opposite direction, i.e., the direction towards the hand of the user. The proximal and distal directions are in parallel to the direction in which a needle of a medical container is to extend. The radial direction should be understood as the direction perpendicular to the proximal and distal directions.

<FIG> shows an exploded perspective view illustrating a medical device <NUM> according to one example. The medical device <NUM> generally has an elongated shape extending along an axial line A, which may also be referred to as "central axis" in this application.

The medical device <NUM> comprises a medical container <NUM> having an elongated barrel <NUM> and a longitudinal tip <NUM> extending distally (as indicated by arrow A1) from a distal end of the barrel <NUM>, and a needle <NUM> attached to the tip <NUM> of the container <NUM>.

The barrel <NUM> has a tubular shape and defines a reservoir <NUM> inside thereof for containing a medical solution. The barrel <NUM> has a flange <NUM> extending radially outwardly from the proximal end of the barrel <NUM>. The barrel <NUM> has a circular opening <NUM> which is generally concentric with the barrel <NUM> and in fluid communication with the reservoir <NUM>. The opening <NUM> allows a plunger (not shown) to advance within the reservoir <NUM> in the distal direction through the opening <NUM> to eject the medical solution contained in the reservoir <NUM>. The medical solution which is to be contained in the reservoir <NUM> may comprise, but not be limited to pharmaceutical composition, vitamins, a vaccine or the like.

The container tip <NUM> is a generally tubular element having a smaller diameter than the barrel <NUM>. The tip <NUM> is smoothly connected to the distal end of the barrel <NUM>. The barrel <NUM> and the tip <NUM> are preferably made of glass and integrally formed with each other.

The tip <NUM> defines an inner channel <NUM> extending through the tip <NUM> between its proximal and distal ends (see also <FIG>). The inner channel <NUM> is in fluid communication with the reservoir <NUM>.

The tip of the container <NUM> has a complementary snap feature <NUM>. In this example, the complementary snap feature <NUM> is a bump on an outer circumferential face of the tip <NUM>. The bump <NUM> protrudes radially outwardly relative to the remaining surface of the tip <NUM>. However, the complementary snap feature <NUM> could also be a groove.

The needle <NUM> has a pointed distal end <NUM> and a proximal end <NUM> which is fixed within the inner channel <NUM> of the tip <NUM> by glue or any other known means acceptable to medical use. The needle <NUM> is a hollow element the inside of which is in fluid communication with the reservoir <NUM> through the inner channel <NUM> of the tip <NUM>. When the needle <NUM> is assembled with the container <NUM>, the distal end <NUM> of the needle <NUM> sticks out of the tip <NUM>.

The medical device <NUM> is provided with a safety assembly <NUM> for preventing needle stick injury with the needle <NUM>.

The safety assembly <NUM> comprises an attachment ring <NUM>, and a safety device attached to the attachment ring and intended to cover at least the pointed distal end of the needle.

The attachment ring <NUM> comprises an inner ring <NUM> and an outer ring <NUM>.

The inner ring <NUM> is configured to be clipped on the tip of the container. More precisely, the inner ring <NUM> is provided with at least a snap feature configured to engage the complementary snap feature of the tip <NUM> of the container.

The inner ring <NUM> and the outer ring <NUM> are preferably made of a plastic suitable to medical use. The inner ring <NUM> and the outer ring <NUM> may be made of the same material or of different materials. The material used for the inner ring <NUM> and the outer ring <NUM> may comprise, but not be limited to, high density polyethylene (PE), polypropylene (PP), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM), polystyrene (PS), polybutylene terephthalate (PBT), polyamide (PA), and their combinations. Using such plastic materials, the inner and outer rings can be provided with suitable shapes (e.g. self-engaging features, sharp edges, etc.) that allow snapping the outer ring to the inner ring with a high pullout resistance.

Besides, as compared to a snapped connection between a glass tip comprising a bump protruding radially outwardly and a conventional plastic ring comprising a complementary groove engaging the bump, the snapped connection between the inner and outer rings has a greater pullout resistance. Indeed, glass forming does not allow creating a bump with sharp edges, which is detrimental to the pullout force of the snapped connection with a conventional plastic ring. This problem is avoided by providing a connection (between the tip and the attachment ring) whose pull-out resistance essentially depends on the strong snapped connection between the inner ring and outer ring that are both made of plastic, rather than on the weaker connection between the glass tip and the plastic ring. As a result, the pullout resistance of the connection between the safety device and the glass tip can be increased.

In the illustrated examples, wherein the complementary snap feature is a bump protruding radially outwardly from an outer face of the tip of the container, the snap feature comprises a groove delimited proximally by an inwardly protruding protrusion 25a. The groove is configured to receive the bump. Conversely, the complementary snap feature could be a groove and the snap feature could be a lip configured to be inserted into the groove.

By "safety device" is meant in the present text a device configured to protect a user from needle stick injury after the injection of the medical solution has been carried out.

According to an embodiment, the safety device comprises a protective arm <NUM> adapted to be attached to the attachment ring <NUM>, and a protective cap <NUM> adapted to be inserted on the attachment ring. The protective cap and the protective arm are preferably similar to those described in the patent application <CIT>.

More precisely, the protective cap <NUM> is adapted to be mounted on the tip of the medical container to cover the needle. The protective cap <NUM> comprises a proximal extremity provided with at least an engaging peg <NUM>. The protective cap <NUM> may comprise a needle shield <NUM> and a rigid shield <NUM> or only one single shield. The protective cap <NUM> preferably comprises a sleeve portion configured to be inserted onto the attachment ring <NUM>.

The protective arm <NUM> is attached to the attachment ring by a pivot link such that it may adopt:.

The protective arm <NUM> comprises a cam surface <NUM> at its proximal extremity. The cam surface <NUM> of the protective arm and the engaging peg <NUM> of the protective cap are configured so that, removing the protective cap by axial movement shifts the protective arm from a storage position to a retracted position.

The outer ring <NUM> comprises fixing means configured to pivotally fix the protective arm <NUM> on the outer ring <NUM>. The fixing means may for example comprise inserts <NUM> (only one of them is visible in <FIG>) sticking out radially outwardly from the outer ring, while the protective arm comprises openings <NUM> configured to receive the inserts <NUM> so that the protective arm may rotate with respect to the outer ring.

The protective arm <NUM> has a distal cover <NUM> and two legs <NUM> extending from the distal cover <NUM> in the proximal direction A2. Although not illustrated in the drawings, the distal cover <NUM> may comprise a notch intended to accommodate the distal end <NUM> of the needle <NUM>.

The protective arm <NUM> and the rigid shield <NUM> may be made of plastic.

The needle shield <NUM> is a tubular element defining an inner cavity for accommodating the needle <NUM>. The needle shield <NUM> is made of elastomeric material and dimensioned to be accommodated by the rigid shield <NUM>.

<FIG> shows the protective arm <NUM> in a storage position. In this position, the protective arm <NUM> is interlocked with the protective cap <NUM>, which covers the distal end <NUM> of the needle <NUM>. In the storage position, the protective arm <NUM> cooperates with the protective cap <NUM> to prohibit access to the needle <NUM>.

<FIG> shows the protective arm <NUM> in transition from the storage position to a retracted position. When the protective cap <NUM> is moved in the distal direction A1, the engaging peg <NUM> of protective cap <NUM> pushes the cam surface <NUM> of the protective arm <NUM>. The interaction between the engaging peg <NUM> and the cam surface <NUM> results in a rotary movement of the protective arm <NUM> with respect to the outer ring <NUM>.

<FIG> shows the protective arm <NUM> in retracted position. In this position, the protective arm <NUM> is at right angle relative to the needle <NUM> and the protective cap <NUM> is completely removed from the needle <NUM>. As can be seen from the drawing, the safety assembly <NUM> is now open to give full access to the needle <NUM>. The medical device <NUM> is ready to use, for example to inject a medical product into the body of a patient.

<FIG> shows the protective arm <NUM> in a safety position. Once the injection is performed, the user may apply a force to the protective arm <NUM> to rotate the protective arm <NUM> back in order to cover the needle <NUM> with the protective arm <NUM>.

The protective cap <NUM> is illustrated by way of example and may also have other configurations. For example, the protective cap <NUM> may comprise only one shield, e.g. the rigid shield <NUM>.

Besides, the invention is not limited to a safety device comprising a protective cap and a protective arm as illustrated in <FIG> and <FIG>, but to any safety device intended to be attached to the tip of the medical container. To that end, the safety device comprises a part configured to be attached to the outer ring <NUM>. For sake of concision only and without any intended limitation, the following description is based on the safety device illustrated in <FIG> and <FIG>.

Referring to <FIG>, the inner ring <NUM> will be described. The inner ring <NUM> is configured to be snapped on the tip of the medical container. To that purpose, the inner ring <NUM> comprises snap features configured to be snapped into the complementary snap features of the tip of the medical container. In this embodiment, the inner ring <NUM> comprises an annular distal ring 23a, and mounting fingers <NUM> extending proximally from the distal ring 23a. In this embodiment, the inner ring <NUM> is made in a single piece.

The distal ring 23a is dimensioned to receive the tip <NUM> of the container <NUM>.

Each mounting finger <NUM> has a snap feature. In this embodiment, the snap feature comprises a groove <NUM> and an inwardly protruding protrusion 25a at its proximal end. In the illustrated example, two mounting fingers <NUM> are provided, but the inner ring <NUM> may have three or more mounting fingers.

The mounting fingers <NUM> are preferably diametrically opposed to each other around the central axis.

The inner ring <NUM> has a groove <NUM> formed on the inner circumference of the inner ring <NUM> around the central axis. The groove <NUM> runs on the inner face of the mounting fingers <NUM>. A proximal end of the groove <NUM> is delimited by the inwardly protruding protrusions 25a of the mounting fingers <NUM>. A distal end of the groove <NUM> could be directly delimited by the distal ring 23a or by a distal protrusion between the groove and the distal ring. The groove <NUM> is configured to receive the bump <NUM> on the tip <NUM>.

The inner ring <NUM> is configured to be inserted on the tip <NUM> of the container <NUM> by axially moving the inner ring <NUM> towards the tip <NUM>. During the axial movement of the inner ring <NUM> towards the tip <NUM>, the inwardly protruding protrusions <NUM> move radially outwardly and the mounting fingers <NUM> are flexed outwardly, so that the inwardly protruding protrusions 25a can move beyond the bump <NUM>. When the inwardly protruding protrusions 25a are proximally from the bump <NUM>, the inner ring is securely attached to the container's tip. The inwardly protruding protrusions 25a are maintained proximally from the bump <NUM> thanks to the outer ring as explained thereafter.

Referring to <FIG>, the outer ring <NUM> will be described. The outer ring <NUM> is configured to be clipped on the inner ring <NUM>. The outer ring <NUM> has a sleeve portion <NUM> surrounding at least one part of the inner ring in order to prevent radial movement of the snap feature, thereby enabling to maintain the snap feature engaged with the complementary snap feature.

More precisely, in this embodiment, the sleeve portion <NUM> is configured to surround the mounting fingers <NUM> of the inner ring <NUM>. The sleeve portion <NUM> defines an inner circumference around the central axis. The sleeve portion <NUM> receives at least part of the mounting fingers <NUM> of the inner ring <NUM>, thereby preventing radial movement of the inwardly protruding protrusions 25a, as well as radial deformation of the mounting fingers <NUM>.

The outer ring further comprises clipping features enabling to snap the outer ring on the inner ring. In this embodiment, the clipping features comprise locking fingers <NUM>. The locking fingers <NUM> are configured to clip on the inner ring <NUM>, thereby interlocking the inner ring <NUM> and the outer ring <NUM>. Each locking finger <NUM> has a distal end 26a connected to the sleeve portion <NUM> and a proximal end 26b which protrudes radially inwardly. The proximal end 26b of the locking finger <NUM> is configured to be engaged with a flange <NUM> of the inner ring <NUM> which extends radially outwardly from the circumference of the inner ring <NUM>, thereby interlocking the inner ring <NUM> and the outer ring <NUM>.

The outer ring <NUM> may also have inner protrusions <NUM>. The inner protrusions <NUM> extend radially inwardly. The inner protrusions <NUM> are preferably provided at the distal end of the outer ring <NUM>. The inner protrusions <NUM> may have curved inner faces. The inner protrusions <NUM> are configured to frictionally engage the tip <NUM> of the container <NUM>. Accordingly, the inner protrusions <NUM> are in contact with the outer circumferential face of the tip <NUM> when the outer ring <NUM> is fixed on the inner ring <NUM>. The inner protrusions <NUM> prevent rotation between the safety assembly and the medical container.

The attachment ring <NUM> is used to attach the protective arm <NUM> and the protective cap <NUM> to the container <NUM>.

Now turning to <FIG>, process of assembling the attachment ring <NUM> with the medical container <NUM> will be described.

First, the inner ring <NUM> is brought in axial alignment with tip <NUM> and moved towards the container <NUM> in the proximal direction A2 (<FIG>). When the inner ring <NUM> reaches the bump <NUM> of the tip <NUM>, the inwardly protruding protrusions 25a of the mounting fingers <NUM> come in contact with the bump <NUM> on the tip <NUM>. As the inwardly protruding protrusions 25a move beyond the bump <NUM>, the mounting fingers <NUM> elastically deform radially outwardly by the bump <NUM> on the tip <NUM>. When the inner ring <NUM> advances farther in the proximal direction A2, the mounting fingers <NUM> return to their original shape and as a result the bump <NUM> is accommodated within the groove <NUM> of the inner ring <NUM>. Thanks to the engagement between the bump <NUM> and the groove <NUM> of the inner ring <NUM>, axial movement of the inner ring <NUM> relative to the container <NUM> can be prevented.

Then, the outer ring <NUM> is introduced onto the tip <NUM> in the proximal direction A2 (<FIG>). As the outer ring <NUM> is brought into contact with the inner ring <NUM>, the locking fingers <NUM> of the outer ring <NUM> deform radially outwardly since the proximal ends 26a of the locking fingers <NUM> protrude radially inwardly. Once the proximal ends 26a of the locking fingers <NUM> move beyond the inner ring <NUM>, the locking fingers <NUM> return to their original shapes, which establishes engagement between the locking fingers <NUM> and the inner ring <NUM> (<FIG>).

As shown in <FIG>, when the attachment ring <NUM> is assembled with and in position relative to the container <NUM>, the bump <NUM> of the container <NUM> is received within the groove <NUM> of the inner ring <NUM>. In addition, the locking fingers <NUM> of the outer ring <NUM> are engaged with a flange <NUM> of the inner ring <NUM> which extends from the proximal end of the inner ring <NUM>. This configuration can advantageously prevent axial movement of the inner ring <NUM> relative to the container <NUM>, as well as axial movement of the outer ring <NUM> relative to the inner ring <NUM>. In the illustrated embodiment, the flange <NUM> corresponds to the proximal end of the mounting fingers <NUM>.

According to this example, pull-out force which would be required to pull the attachment ring <NUM> from the container tip <NUM> is increased. In particular, the sleeve portion <NUM> of the outer ring <NUM> surrounds the mounting fingers <NUM> of the inner ring <NUM> and prevents the mounting fingers <NUM> from deforming radially outwardly. Since the radial deformation of the mounting fingers <NUM> would be required to disengage the inner ring <NUM> from the bump <NUM> of the container, it is ensured that the interlock between the attachment ring <NUM> and the container tip <NUM> is maintained.

The sleeve portion <NUM> of the outer ring <NUM> can prevent any radial movement of the inwardly protruding protrusions 25a of the mounting fingers <NUM>, thereby preventing the inner ring <NUM> from being removed from the container <NUM>.

As shown in <FIG>, the inner protrusions <NUM> are frictionally engaged with the outer surface of the container tip <NUM>. Thanks to the friction generated between the inner protrusions <NUM> and the tip <NUM>, a rotational torque that may be applied to the outer ring <NUM> is prevented from being transmitted to the inner ring <NUM>. This is also advantageous to ensure that the attachment ring <NUM> is reliably attached to the container <NUM>.

<FIG> show another example of the attachment ring <NUM>. According to this example, the inner ring <NUM> further has an outer groove <NUM>. The outer groove <NUM> is on an external face of the inner ring <NUM>. The outer groove <NUM> is arranged between the distal ring 23a and the proximal end of the mounting fingers <NUM>. The outer groove <NUM> is an annular groove intended to receive the locking fingers <NUM> of the outer ring <NUM>.

The inner ring <NUM> can be snap-fit to the container tip <NUM> in the same way as the inner ring <NUM> shown in <FIG>. The inner ring <NUM> is introduced onto the tip <NUM> in the proximal direction A2 (see <FIG>). As the inner ring <NUM> comes in contact with the bump <NUM> on the tip, the inwardly protruding protrusions 25a of the mounting fingers <NUM> are raised by the bump <NUM>, the mounting fingers <NUM> deform radially outwardly. Then, the inner ring <NUM> further advances in the proximal direction A2 until the inwardly protruding protrusions 25a move beyond the bump <NUM> and the bump <NUM> is accommodated within the groove <NUM> of the inner ring <NUM> (<FIG>).

Thereafter, as shown in <FIG>, the outer ring <NUM> is introduced onto the inner ring <NUM>. The outer ring <NUM> has locking fingers <NUM> in a corresponding position to the outer groove <NUM> such that the sleeve portion <NUM> surrounds the mounting fingers <NUM> of the inner ring <NUM>, and at the same time the locking fingers <NUM> engage with the outer groove <NUM>. The engagement between the inner ring <NUM> and the outer ring <NUM> is illustrated in <FIG>.

According to another example shown in <FIG>, the end walls (proximal and distal end faces) of the outer groove <NUM> of the inner ring <NUM> for receiving the locking fingers <NUM> are inclined relative to a plane perpendicular to the central axis of the inner ring <NUM>. The inclination angle may be of <NUM> degrees. However, the inclination angle may also range between <NUM> degrees and <NUM> degrees, preferably between <NUM> and <NUM> degrees. The inclined walls of the outer groove enable to have a better attachment between the tip of the container and the inner ring.

The end walls of the groove <NUM> of the inner ring <NUM> which are configured to receive the bump <NUM> of the container tip <NUM> may also be inclined. The inclination angle may be at <NUM> degrees. However, the inclination angle may also range between <NUM> degrees and <NUM> degrees, preferably between <NUM> and <NUM> degrees. Thanks to the inclined end walls of the grooves <NUM>, the interlock between the outer ring <NUM> and the inner ring <NUM> is more reliable.

Referring to <FIG>, a safety assembly according to yet another example will be described. In this example, the inner ring <NUM> comprises two half rings 21A and 21B. The inner ring <NUM> is separable by moving the half rings 21A and 21B radially outwardly.

As shown in <FIG>, <FIG>, each half ring 21A and 21B has an inner face provided with a snap feature configured to engage the complementary snap feature of the tip of the container. In this example, the snap feature comprises a groove <NUM> configured to be clipped on the bump <NUM> of the container's tip <NUM>. However, the snap feature could also be a lip configured to be inserted in a groove of the tip of the container.

As previously described, the outer ring <NUM> is clipped on the inner ring such that the sleeve portion <NUM> surrounds the two half rings 21A and 21B when assembled together, thereby preventing radial movement of the two half rings 21A and 22B. Since the two half rings 21A and 21B cannot move radially, the snap feature is maintained engaged with the complementary snap feature such that the attachment ring cannot move axially.

The half rings 21A and 21B may have a flange <NUM> onto which the locking fingers <NUM> of the outer ring <NUM> can be snapped (see <FIG>). In this example, the flange <NUM> may be formed on an outer face of the inner ring <NUM>.

The flange <NUM> has a proximal wall that is inclined relative to a plane which extends perpendicular to a central axis of the inner ring, so as to increase the pull-out force required to pull the locking fingers <NUM> of the outer ring from the flange <NUM>. This ensures that the attachment ring cannot be removed easily by accident.

Although this inclination of the flange is illustrated on <FIG>, it could be applied also to the other embodiments described in the present text.

The half rings 21A and 21B may be identical. The half rings 21A and 21B may also be each provided with hook portions 33A and 33B at opposite ends in the circumferential direction. The hook portions 33A and 33B have complementary shapes to each other such that the half rings 21A and 21B can be interlocked with each other.

As shown in <FIG> and <FIG>, the inner ring <NUM> can be assembled by bringing the two half rings 21A and 21B closer to each other in the radially inwardly and interlock them by way of the hook portions 33A and 33B. When the inner ring <NUM> is attached to the container tip <NUM> (<FIG>), the bump <NUM> of the tip <NUM> is accommodated within the groove <NUM> of the inner ring <NUM>.

The outer ring <NUM> can then be snap-fit with the inner ring <NUM> by introducing the outer ring <NUM> in the proximal direction A2 (see <FIG>) so that the sleeve portion <NUM> of the outer ring <NUM> surrounds the two half rings 21A and 21B. As can be seen from <FIG>, the sleeve portion <NUM> of the outer ring <NUM> extends over the half rings 21A and 21B, thereby holding them together, preventing them from moving radially outwardly to disengage the hook portions 33A and 33B.

According to this example, the radial movement of the two half rings 21A and 21B, which is required to detach the inner ring <NUM> from the container tip <NUM>, can be prevented by the sleeve portion <NUM> of the outer ring <NUM>. In addition, the outer ring <NUM> is clipped on the inner ring <NUM>. Therefore, the connection between the attachment ring <NUM> and the container becomes more reliable.

Further, the inner ring <NUM> can be easily attached to the tip <NUM> of the container, simply by bringing the two half rings 21A and 21B closer to each other and engaging the corresponding hook portions 33A and 33B. The assembling process of the inner ring <NUM> is simplified, and the manufacturing cost of the safety assembly <NUM> can be reduced.

When the half rings 21A and 21B are identical, the manufacturing cost of the safety assembly <NUM> can be reduced.

<FIG> shows another example of the half rings 21A and 21B. According to this embodiment, the half rings 21A and 21B are integrally formed with each other and connected via a hinge <NUM>. The half rings 21A and 21B can be assembled with or disassembled from each other by pivot movement of the half rings 21A and 21B about the hinge <NUM>. This can facilitate process of assembling the two half rings 21A and 21B to form the inner ring <NUM>.

The safety assembly <NUM> may also be used with any medical container equipped with a needle which poses a potential risk of needle stick injury, including but not being limited to pen-injectors, catheters, blood collection devices. The medical device <NUM> may be used for delivering a pharmaceutical composition, vitamins, a vaccine or any other type of medical solution to the body of a patient or for taking samples from the body of a patient.

Claim 1:
A safety assembly (<NUM>) for preventing needle stick injury with a needle (<NUM>), the needle having a proximal end (<NUM>) fixed to a tip (<NUM>) of a medical container (<NUM>) and a pointed distal end (<NUM><NUM>), the safety assembly comprising:
- an attachment ring (<NUM>) configured to be attached to the tip (<NUM>) of the container (<NUM>);
- a safety device configured to cover at least the distal end (<NUM><NUM>) of the needle, the safety device configured to be attached to the attachment ring (<NUM>);
the safety assembly (<NUM>) being characterized in that the attachment ring (<NUM>) comprises:
∘ an inner ring (<NUM> ) having an inner face provided with a snap feature, the snap feature being configured to engage a complementary snap feature on the tip of the container in order to prevent axial movement of the inner ring with respect to the container, the snap feature being configured to move radially to engage the complementary snap feature on the tip of the container;
∘ an outer ring (<NUM>) fixed on the inner ring (<NUM> ), the outer ring (<NUM>) comprising a sleeve portion (<NUM>) configured to surround at least a portion of the inner ring in order to prevent radial movement of the snap feature (25a) once the snap feature has engaged the complementary snap feature on the tip of the container.