Patent Description:
In this application, the distal end of a component or of a device is to be understood as meaning the end furthest from the user's hand and the proximal end is to be understood as meaning the end closest to the user's hand. Likewise, in this application, the "distal direction" is to be understood as meaning the direction of injection, with respect to the safety device or drug delivery device of the invention and the "proximal direction" is to be understood as meaning the opposite direction to said direction of injection, that is to say the direction towards the user's hand.

Drug delivery devices, such as pre-fillable or prefilled syringes, usually comprise a hollow body or barrel forming a container for a medical product. This body comprises a distal end in the form of a longitudinal tip defining an axial passageway through which the medical product is expelled from the container. The distal end is equipped with a needle for injection of the medical product into an injection site.

It is of great importance that the patients and users are protected from any risk of needle stick injuries, particularly between the moment that injection is finished and the discarding of the drug delivery device.

In order to minimize the risks of needle stick injuries, drug delivery devices may be equipped with a safety device that protects the needle after injection. Safety devices usually comprise a tubular body for receiving the syringe barrel, and a needle cover, in the form of a protective sleeve, that slides relative to the tubular body. The needle cover has a retracted position in which the needle cover is substantially contained inside the tubular body to allow a user to carry out an injection, and an extended position in which the needle cover moves distally from the retracted position to cover the needle once the injection is completed.

Although known injection systems are generally satisfactory, they do not always meet all of the user's expectations and they can include a number of components. Therefore, they can be expensive to manufacture and thus this can limit the widespread use of safety devises at the expense of the security of medical users and patients. Such prior art safety devices are e.g. known from <CIT>, which shows the combination of features of the preamble of claim <NUM>. Other prior art safety devices for needle hub applications are known from e.g. <CIT>.

They also tend to include components made of various materials which can be complex and expensive to recycle.

A need exists for an improved safety that provides a user with more convenient safety device that is also cost effective and easy to manufacture.

It is directed to a safety device for mounting onto a drug delivery device having a barrel including with a flange at its proximal end and an injection needle at its distal end, and a piston rod including a piston flange, the safety device including:.

At least one the hinge cab be a living hinge.

The safety device is formed in a single shot injection molding process.

The safety device has a relaxed state in which the arms returns from being in the collapsed position or from being in the extended position.

The proximal link and the distal link form an angle between <NUM>° and <NUM>° in the relaxed position.

The proximal links can include at least one locking hooks configured and sized to enter into resilient snap fit engagement with at least one wings protruding from the annular head to maintain the actuation arm in the extended position.

The head arrangement includes an annular head comprising a locking member which includes a radially oriented wall and two wings extending laterally from the wall.

The annular head includes a longitudinal tongue which extends distally from the locking member and is configured and sized to engage into a channel defined by two guiding walls provided on the tubular body.

The intermediate hinge inwardly overtakes the plan defined by the proximal hinge and distal hinge when the actuation arm is in its extended position.

The annular head can includes a proximal ring and a distal ring jointed by a shoulder whereon the flange abuts.

The distal link can include two orthogonal finger plates.

The annular head comprises at least one locking tab configured to retain the flange.

The tubular body comprises a leg extending in cantilever and having a catch at its free end, the leg being configured to deflect radially outward to allow the catch to slide over the annular head during mounting and to deflect radially inward after mounting completion so that the catch axially retains the tubular body relative to annular head.

The safety device can includes at least one recess positioned at the junction between the shoulder and the distal ring.

The head arrangement can include a crown having a proximal plate configured and sized to lock onto the flange and a distal plate mounted on the tubular body, the proximal plate and the distal plate being connected by at least two actuation arms.

The proximal plate can include two symmetrical ribs, each rib having two locking teeth configured to retain the flange.

The distal link includes at least one looking hook configured and sized to engage into at least one opening provided in the proximal link when the arm is in a collapsed position.

The safety device can includes two legs having a catch, extending in cantilever from the distal plate, configured and sized to engage into a window provided in the proximal plate and to lock into the rib.

The safety device can includes at least one finger tab positioned at the junction of the distal link and the proximal link.

In a second aspect, as defined in claim <NUM>, the invention is directed to a drug delivery device having a barrel including with a flange at its proximal end and an injection needle at its distal end, and a piston rod including a piston flange fitted with a safety device as previously described, wherein the piston flange includes a ramped surface distally convergent configured to outwardly deflect the leg.

With reference to the appended drawings, below follows a more detailed description of aspects and embodiments of the invention cited as examples.

The different features of the embodiments can be used in combination with and used with other embodiments as long as the combined parts are not inconsistent with or interfere with the operation of the device and assembly. This invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The embodiments herein are capable of being modified, practiced or carried out in various ways. The use of "including," "comprising," or "having" and variations thereof herein is to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms "connected," "coupled," and "mounted," and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms "connected" and "coupled" and variations thereof are not limited to physical or mechanical connections or couplings. Further, terms such as distal, proximal, up, down, bottom, and top are relative, and are to aid illustration, but are not limiting. The embodiments are not intended to be mutually exclusive so that the features of one embodiment can be combined with other embodiments as long as they do not contradict each other. Terms of degree, such as "substantially", "about" and "approximately" are understood by those skilled in the art to refer to reasonable ranges around and including the given value and ranges outside the given value, for example, general tolerances associated with manufacturing, assembly, and use of the embodiments. The term "substantially" when referring to a structure or characteristic includes the characteristic that is mostly or entirely present in the structure.

With reference to the Figures, a safety device <NUM> is configured to be mounted onto a drug delivery device <NUM> to protect an injection needle <NUM> of the drug delivery device <NUM> after an injection has been carried out.

The drug delivery device <NUM> may be a prefilled or prefillable syringe. The drug delivery device <NUM> includes a tubular barrel <NUM> defining a reservoir for containing a medical product such as a drug. The tubular barrel <NUM> may be made of a plastic or of a glass material. This barrel <NUM> has a distal shoulder <NUM> provided with a distal tip <NUM> longitudinally protruding from said shoulder <NUM> along a longitudinal axis A. The distal tip <NUM> defines an axial passageway in fluid communication with the reservoir and is equipped with the injection needle <NUM> for injecting the medical product in an injection site. The barrel <NUM> further includes an opposite opened proximal end <NUM> provided with a flange <NUM>. The opened proximal end <NUM> receives a plunger rod <NUM> for pushing a stopper <NUM> located inside the barrel <NUM> to expel the medical product from the reservoir to the injection site via the distal tip <NUM> and the injection needle <NUM>.

The drug delivery device <NUM> may be fitted with a tip cap <NUM> for protecting and sealing the injection needle <NUM> before injection. The tip cap <NUM> may be comprised of a soft inner element <NUM> and a rigid outer element <NUM>.

The piston rod <NUM> is fitted with a plunger flange <NUM> at its proximal end. In some embodiments, the plunger flange <NUM> can include a ramped surface <NUM>. The ramped surface <NUM> is conically convergent toward the distal direction.

Turning to <FIG>, the safety device <NUM> includes a tubular body <NUM>, which extends along the longitudinal axis A and is configured and sized to engage on the barrel <NUM> and a head arrangement which can include an annular head <NUM> configured and sized to engage on the barrel <NUM> and to lock on the flange <NUM>.

In some embodiment, two symmetrical articulated actuation arms <NUM> connect the tubular body <NUM> and the annular head <NUM>. Other embodiments may include three or four actuation arms <NUM>.

The tubular body <NUM> is a tubular element, which has an inner diameter sized and configured so that the tubular body <NUM> can axially slide relative to the barrel <NUM>. In practice, the tubular body <NUM> inner diameter slightly exceeds the external diameter of the barrel <NUM>. In some embodiments, the tubular body <NUM> can be provided with one or more windows <NUM> so that any marking or labelling applied on the barrel <NUM> and so that the drug contained in the barrel <NUM> can be visible to a user prior to injection. In the illustrated embodiments, the tubular body <NUM> is provided with two windows <NUM> spaced apart by <NUM>°.

In some embodiments, the tubular body <NUM> can comprise two tabs <NUM> positioned at its proximal end. The tabs <NUM> extends radially from the outer surface of the tubular body <NUM> and the tabs <NUM> can be oriented substantially perpendicular to the longitudinal axis A.

The tubular body <NUM> further comprises two legs <NUM>. The legs <NUM> extend in cantilever from each tab <NUM> in the proximal direction. In some embodiments, the legs <NUM> can have an arched shape with an inward facing concavity. The cantilevered attachment of the legs <NUM> onto the tabs <NUM> combined with its arched shape provide the legs <NUM> with elastic resilience in a radial direction relative to the tubular body <NUM>. At the end of the legs <NUM>, is a catch <NUM>, which is internally oriented. In some embodiments, the catch <NUM> has a ramped end.

Now turning to <FIG>, the annular head <NUM> comprises a distal ring <NUM> attached by a shoulder <NUM> to a proximal ring <NUM>. The distal ring <NUM> is coaxial with the tubular body <NUM> and has an inner diameter, which substantially equates the inner diameter of the tubular body <NUM>.

As can be seen on <FIG>, the proximal ring <NUM> can be provided with one or more locking tabs <NUM>, which radially protrude from the inner surface of said proximal ring <NUM>. In the illustrated embodiments, the proximal ring <NUM> includes four locking tabs <NUM> spaced apart by <NUM>°.

In some embodiments, the annular head <NUM> further comprises two projecting locking member <NUM>. Each projecting locking member <NUM>, which extends from the shoulder <NUM> and the distal ring <NUM>, has a substantially T shaped cross section and includes a radially oriented wall <NUM>, which protrudes from the distal ring <NUM>. At its free end, the wall <NUM> is provided with two wings <NUM>, which extend from the wall <NUM> in a substantially perpendicular direction. Each projecting locking member <NUM> can further include a ramped nose <NUM>, which tapers in a distal direction. In some embodiments, each projecting locking member <NUM> includes two parallel guiding ears <NUM>. The guiding ears <NUM> protrude from the proximal ring <NUM> on the side of the wings <NUM>.

The annular head <NUM> and the tubular body <NUM> are linked by the two articulated actuation arms <NUM>, which each includes a proximal link <NUM> and a distal link <NUM>.

The proximal link <NUM> has a substantially rectangular shape and is connected to the annular head <NUM> by a first proximal hinge <NUM>. The annular head <NUM> has two spaced apart parallel arms <NUM>, which are connected to two corresponding arms <NUM> made in the proximal link <NUM>. The first proximal hinge <NUM> thus connects the two arms <NUM> and the two arms <NUM> of the proximal link <NUM>. The two arms <NUM> define a window <NUM> in the proximal link <NUM>. In the illustrated embodiment, the first proximal hinge <NUM> is a living hinge formed by a thinning of the plastic material, which the safety device <NUM> is made of. This allows the proximal link <NUM> to rotate relative to the arms <NUM> and <NUM>. The proximal links <NUM> further may comprise two locking hooks <NUM>, which protrude from its internal face. The two locking hooks <NUM> are sized and shaped to create a snap fit engagement with the wings <NUM> of the projecting locking member <NUM>. To this end, the locking hooks <NUM> can include a ramped finger <NUM> and the wings <NUM> can also have a tapered cross section. It can be envisaged to provide the proximal link <NUM> with a single locking hook <NUM>.

In some embodiments, the distal link <NUM> has a substantially rectangular shape and is connected to the tab <NUM> by a second distal hinge <NUM> which can be a living hinge made by a thinning of the plastic material which forms the safety device <NUM>. As shown more clearly on <FIG>, the distal link <NUM> can include a proximal and a distal finger plates <NUM>, <NUM> which can be substantially orthogonally positioned and are linked by a longitudinal rib <NUM> which rigidly joins the two finger plates <NUM> and <NUM>.

The proximal link <NUM> and the distal link <NUM> are joined by an intermediate hinge <NUM>, which can be a living hinge made by a thinning of the plastic material which forms the safety device <NUM>.

Thus in some embodiments, the safety device <NUM> comprises two articulated actuation arms <NUM> which connect the tubular body <NUM> and the annular ring <NUM> and comprises a unitary structure integrally molded of thermoplastic material.

In some embodiments, the safety device <NUM> can be a single piece component. Further, the safety device <NUM> can be formed by a single shot molding process. The plastic polymer used in the molding process can be a suitable polymer such as thermoplastic, which provides a shape memory to the safety device <NUM> configured to recover its original shape from deformation when a force has been applied.

In some embodiments, in an initial and relaxed state, (see e.g. <FIG>), after manufacturing by injection molding, the safety device <NUM> is configured in a state wherein the annular head <NUM> and the tubular body <NUM> are axially spaced apart while the proximal link <NUM> and the distal link <NUM> form a substantially right angle. In practice, the angle between proximal link <NUM> and the distal link <NUM> can be comprised between for example <NUM>° and <NUM>°. When an axial force is applied to the safety device <NUM>, the actuation arms <NUM> may bend about the living hinges <NUM>, <NUM> and <NUM> and flex radially outwardly or inwardly depending on the force direction. When the force ceases to apply on the safety device <NUM>, it regains its initial and relaxed state. The actuation arms <NUM> are therefore transitionable from an initial and relaxed state where the proximal link <NUM> and distal link <NUM> form a first angle - substantially right angle - to:.

Starting with a safety device <NUM> as shown on <FIG>, the safety device <NUM> can be moved into a collapsed position as shown on <FIG>.

To do so, the tubular body <NUM> is pushed in a proximal direction so that the legs <NUM> which extend from said tubular body <NUM> deflects against the noses <NUM>, this being made smooth by the ramped catch <NUM> deflecting against the tapered nose <NUM>. The legs <NUM> are then channeled between the guiding ears <NUM>. At the end of the push, the catch <NUM> locks against the free end of the proximal ring <NUM> achieving an appropriate retention of the tubular body <NUM> onto the annular ring <NUM> as illustrated on <FIG>. In this locked state, the actuation arms <NUM> are pushed in a collapsed state as can be seen on <FIG>. In some embodiments, the actuation arm <NUM> in its collapsed state has the proximal link <NUM> substantially perpendicular to the axis A whereas the proximal finger plate <NUM> is substantially parallel to the longitudinal axis A and the distal plate is substantially perpendicular to the longitudinal axis A.

In this collapsed configuration, the safety device is in a stable state and can be shipped and stored for later use or can be immediately engaged on a drug delivery device.

In an exemplary use, the safety device <NUM> can be engaged on a drug delivery device <NUM>, which can be a prefilled syringe as illustrated on <FIG>.

The drug delivery device distal end is inserted through the annular head <NUM> and is pushed in a distal direction (see e.g. <FIG>). The annular head <NUM> is locked onto the barrel flange <NUM>. As best seen on <FIG>, the locking tabs <NUM> deflect when the annular head <NUM> is pushed in a proximal direction so that the annular head <NUM> is retained on the barrel flange <NUM>.

The drug delivery device <NUM> is axially locked on the safety device <NUM>, however the drug delivery device <NUM> is free to rotate relative to the safety device <NUM>, which can be useful as user tend to rotate any drug delivery device before injection to visually check the drug which is about to be injected.

The drug delivery device fitted with a safety device <NUM> as illustrated on <FIG> can be stored for a later use.

When an injection of the drug contained in the drug delivery device <NUM> is required, a user may first remove the tip cap <NUM>.

The drug delivery device <NUM> is ready for injection. The user can visually check the drug through the windows <NUM> and can rotate the plunder rod <NUM>.

Administering an injection with a drug delivery device fitted with the safety device <NUM> is substantially the same as administering an injection with a drug delivery device fitted with the safety device <NUM> according to the prior art and thus is not likely to confuse a user and permits a user-friendly operation.

In an exemplary use illustrated on <FIG>, the user can apply a pushing force on the piston rod flange <NUM> typically by applying a thumb on the piston rod flange <NUM> while the user maintains one finger - typically the index - on one distal link <NUM> and one finger - typically the middle finger - on the other distal link <NUM>.

In embodiments where the distal links <NUM> include two orthogonal finger plates <NUM>, <NUM>, the distal finger plates <NUM> provide an intuitive and ergonomic surface to place fingers.

As the injection progresses, the piston rod flange <NUM> moves closer to the annular head <NUM>. At the end of the injection, the piston rod flange <NUM> abuts against the catch <NUM>. By further pushing the piston rod flange <NUM>, the ramp portion <NUM> comes in abutment with the ramp provided in the catch <NUM> of each legs <NUM> as indicated by the arrows of <FIG>. The legs <NUM> are thus forced to deflect outwardly thereby releasing the catch <NUM>. The actuation arms <NUM> and the tubular body <NUM> are released from the annular head <NUM> and are therefore free to move axially along the barrel <NUM>.

In one or more embodiment, as they are free, the actuation arms <NUM> move toward their initial and relaxed state where the proximal link <NUM> and the distal link <NUM> form a substantially right angle depending on the material and the injection process used to manufacture the safety device <NUM>.

As the actuations arms <NUM> return to their initial and relaxed position, the tubular body <NUM> moves axially on a distal position and covers at least partially the needle <NUM>. However, in this state the tubular body <NUM> is still free to move in the proximal direction.

This is why, the safety device <NUM> is moved to a locked extended position. To achieve this, the user can exert a radial force on each actuation arms <NUM>. The user can place one finger - shown by a radial arrow on <FIG> - on the proximal finger plate <NUM> of one actuation arm <NUM> and one finger - shown by a radial arrow on <FIG> - on the other proximal finger <NUM> plate of the other actuation arm <NUM>; both proximal finger plates <NUM> are intuitive and friendly to use. The arrows of <FIG> show where the user applies a force with the fingers of one hand and with the fingers of two hands.

By doing so, the actuation arms <NUM> move into an extended state distally pushing the tubular body <NUM> into a position where the tubular body <NUM> entirely encapsulates the needle <NUM>.

At the end of the pushing on the actuation arms <NUM>, the two locking hooks <NUM> lock into the wings <NUM> of the projecting locking member <NUM> and maintain the actuation arms <NUM> in their respective extended positions where the tubular body <NUM> is pushed distally and thus the tubular body <NUM> shields the needle <NUM> from post-injection needle stick as seen in <FIG>.

In some embodiments, the engagement of the locking hooks <NUM> on the wings <NUM> produces an audible and/or a tactile signal indicating that locking is positively achieved.

In some embodiments, the actuation arms <NUM> are in a state where the intermediate hinge <NUM> inwardly overtakes the plan defined by the proximal hinge <NUM> and distal hinge <NUM> as it can be best seen on <FIG>. Thus, a force applied longitudinally on the tubular body <NUM> aiming at un-shielding the needle tip <NUM> cannot release the actuation arm <NUM> from its extended state. The tubular body <NUM> is locked in an extended state by the locking hooks <NUM>; locking is further achieved by the proximal link <NUM> and distal link <NUM> which are arranged as a toggle mechanism.

The protective device <NUM> accordingly achieves a substantially permanent locking of the tubular body <NUM> over the needle tip <NUM>.

In an embodiment of the invention illustrated on <FIG>, the annular head <NUM> includes two longitudinal tongues <NUM>, which each extends distally from the locking member <NUM>. The longitudinal tongue <NUM> has a substantially flat cross section and includes a corrugation <NUM> at its distal end.

The tubular body <NUM> is further provided with two parallel guiding walls <NUM>, which extend from each tab <NUM> in a distal direction. Each pair of guiding walls <NUM> define a channel <NUM>, configured and sized to receive the tongue <NUM>. In the illustrated embodiment, each the tab <NUM> includes a window <NUM> to allow the tongue <NUM> insertion between the two guiding walls <NUM>. At the distal end of each pair of the guiding walls <NUM>, the tubular body includes a transverse rib <NUM>.

While not shown, the tubular body <NUM> may be held in its collapsed state via one of the corrugation <NUM> being engaged on the transverse rib <NUM> while the tongue <NUM> is engaged between the two guiding walls <NUM> thereby increasing the overall rigidity of the safety device <NUM> when in collapsed state. The elastic snap fit of the corrugation <NUM> on the rib <NUM> can provide an audible and/or tactile feedback to a user.

In one embodiment shown on <FIG>, the annular head <NUM> includes a tab <NUM>, which extends distally from the locking member <NUM>. The tab <NUM> includes a transverse corrugation <NUM> which is sized and configured to engage on a rib <NUM> provided on the annular body <NUM>. The corrugation <NUM> being engaged on the rib <NUM> provides an axially locking force when the actuation arm <NUM> is in its collapsed state.

In one embodiment shown on <FIG>, the safety device <NUM> includes two hooks 46a, which protrude from the inner face of the two proximal link <NUM>. The hooks 46a have a curved free end configured and sized to enter into snap fit engagement with a wing <NUM>. <FIG> further shows where the finger plates protrude from each distal plates. The curved shaped hooks and the finger plates protruding from the distal link tend to make the safety device easier to manufacture by injection molding.

In some embodiments shown on <FIG>, the safety device <NUM> can include one or more recesses configured to reduce the gross weight of the safety device <NUM>. Reducing the gross weight further means that less raw plastic injection material is needed. Manufacturing cycles can be reduced as less material is required and cooling time is improved. In the illustrated embodiment of <FIG>, two recesses <NUM> are provided in the annular ring <NUM>. The recesses <NUM> can be positioned at the junction between the shoulder <NUM> and the distal ring <NUM>. In one or more embodiments, the recesses <NUM> can be located above the projecting locking member <NUM>.

Turning to <FIG>, the safety device <NUM> includes a tubular body <NUM>, and is configured and sized to engage on the barrel <NUM> of a drug delivery device such as a prefilled syringe and a head arrangement which can include a crown <NUM> designed and configured to axially move between a locked collapsed position (<FIG>) and a locked extended position (<FIG>).

The crown <NUM> includes a distal plate <NUM> which is positioned at the proximal end of the tubular body <NUM>. In the illustrated embodiment, the distal plate <NUM> has a quadrangular shape. As it can be seen on <FIG>, the distal plate <NUM> includes two symmetrical legs <NUM>. The legs <NUM> extend in cantilever the distal plate <NUM> in the proximal direction. The cantilevered attachment of the legs <NUM> onto the distal plate <NUM> provides the legs <NUM> with elastic resilience in a radial direction relative to the tubular body <NUM>. At the end of the legs <NUM>, is a catch <NUM>, which is internally oriented. In some embodiments, the catch <NUM> has a ramped end.

The crown <NUM> includes a proximal plate <NUM> which can have a quadrangular shape. On its proximal face, the proximal plate <NUM> is provided with locking elements where the flange <NUM> can engage the locking elements.

The proximal plate <NUM> and the distal plate <NUM> are provided with two coaxial circular openings <NUM> and <NUM>.

In some embodiments, the proximal plate <NUM> can include two symmetrical ribs <NUM>. Each ribs <NUM> can be provided with two cantilevered locking tooth <NUM>.

The proximal plate <NUM> can include two windows <NUM> which are each adjacent a ribs <NUM>. The windows <NUM> are configured and sized to receive a leg <NUM>. In other words, the legs <NUM> can engage the windows <NUM> and the catches <NUM> can lock onto the ribs <NUM> when the safety device <NUM> is in a collapsed position.

The crown <NUM> further includes two arms <NUM> which connect the distal plate <NUM> to the proximal plate <NUM>. Each arm <NUM> includes a proximal link <NUM> and a distal link <NUM>.

The proximal links <NUM> have a substantially rectangular shape and are each connected to proximal plate <NUM> by a first proximal hinge <NUM>. In the illustrated embodiment, the first proximal hinges <NUM> are living hinges formed by a thinning of the plastic material, which the safety device <NUM> is made of. This allows the proximal links <NUM> to rotate relative to proximal plate <NUM>. The proximal links <NUM> can be provided with two openings <NUM>.

The distal links <NUM> have a substantially rectangular shape and are each connected to the distal plate <NUM> by a distal hinge <NUM> which can be a living hinge made by a thinning of the plastic material which forms the safety device <NUM>.

The proximal link <NUM> and the distal link <NUM> can be joined by an intermediate hinge <NUM>, which can be a living hinge made by a thinning of the plastic material which forms the safety device <NUM>.

The distal links <NUM> can each include two locking hooks <NUM>, which protrude from its internal face. The locking hooks <NUM> are sized and shaped to create (i) a snap fit engagement with the openings <NUM> provided in the proximal links <NUM> where the proximal links <NUM> and the distal links <NUM> are substantially parallel see <FIG> and (ii) a snap fit engagement with the legs <NUM> where the proximal links <NUM> and the distal links <NUM> are in line with each other substantially see <FIG>.

In some embodiments, the arms <NUM> can be each provided with finger tabs <NUM>. The finger tabs <NUM> can be positioned at the intermediate hinges <NUM>.

The actuation arms <NUM> are therefore transitionable between:.

In some embodiments, the safety device <NUM> can be a single piece component. Further, the safety device <NUM> can be formed by a single shot molding process.

In its collapsed position shown on <FIG>, the proximal link <NUM> and the distal link <NUM> are parallel and are maintained against each other by the locking hooks <NUM> which engage into the openings <NUM>. Further, the legs <NUM> engage the windows <NUM> and lock into the ribs <NUM>.

In its extended position shown on <FIG> and <FIG>, the proximal link <NUM> and the distal link <NUM> are in line with each other and the locking hooks <NUM> retain the legs <NUM>.

<FIG> shows the safety device <NUM> fitted on a drug delivery device <NUM> which can be a prefilled syringe.

In this collapsed position, the crown <NUM> is locked onto the drug delivery device <NUM>. To do so, the barrel flange <NUM> locks onto the ribs <NUM>. The barrel flange <NUM> snaps fit onto the locking tooth <NUM>.

As the injection progresses, the piston rod flange <NUM> moves closer to the crown <NUM>. At the end of the injection, the piston rod flange <NUM> abuts against the catches <NUM>. By further pushing the piston rod flange <NUM>, the ramp portion <NUM> comes in abutment with the ramp provided in the catch <NUM> of each legs <NUM> as indicated by the arrows of <FIG>. The legs <NUM> are thus forced to deflect outwardly thereby releasing the catches <NUM> from the ribs <NUM>. The actuation arms <NUM> and the tubular body <NUM> are released from the proximal plate <NUM> and are therefore free to move axially along the barrel <NUM>.

The user can exert a radial force on each actuation arms <NUM>. To do so, the user can place one finger on one finger tab <NUM> and another finger on the other finger tab <NUM>.

At the end of the pushing on the actuation arms <NUM>, the two locking hooks <NUM> lock into the legs <NUM> and maintain the actuation arms <NUM> in their respective extended positions where the tubular body <NUM> is pushed distally and thus the tubular body <NUM> shields the needle <NUM> from post-injection needle stick as seen on <FIG>.

In some embodiments, the engagement of the locking hooks <NUM> on the legs <NUM> produces an audible and/or a tactile signal indicating that locking is positively achieved.

Claim 1:
A safety device (<NUM>,<NUM>) for mounting onto a drug delivery device (<NUM>) having a barrel (<NUM>) including with a flange (<NUM>) at its proximal end and an injection needle (<NUM>) at its distal end, and a piston rod (<NUM>) including a piston flange (<NUM>), the safety device (<NUM>) including:
a tubular body (<NUM>,<NUM>) extending along a longitudinal axis (A), the tubular body (<NUM>,<NUM>) being configured to receive the barrel (<NUM>),
a head arrangement (<NUM>,<NUM>,<NUM>,<NUM>) configured to abut against the flange (<NUM>) and to lock into the flange (<NUM>), the safety device being characterized by
at least two actuation arms (<NUM>,<NUM>) connecting the tubular body (<NUM>) and the head arrangement, said actuation arms (<NUM>,<NUM>) having a proximal link (<NUM>,<NUM>) connected to the head arrangement by a proximal hinge (<NUM>,<NUM>) and a distal link (<NUM>,<NUM>) connected to the tubular body (<NUM>,<NUM>) by a distal hinge (<NUM>,<NUM>), the proximal link (<NUM>,<NUM>) and the distal link (<NUM>,<NUM>) being connected by an intermediate hinge (<NUM>,<NUM>), the actuation arms (<NUM>,<NUM>) being movable between a collapsed position in which the tubular body (<NUM>,<NUM>) is maintained in a position proximally close to the flange (<NUM>) uncovering the needle (<NUM>) and an extended position in which the tubular body (<NUM>,<NUM>) is maintained in a position distally distant from the head arrangement shielding the needle (<NUM>);
a locking means (<NUM> ,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) for releasably maintaining the actuation arms (<NUM>,<NUM>) in said collapsed position and a locking means (<NUM>,<NUM>,<NUM> ,<NUM>) for maintaining the actuation arms (<NUM>,<NUM>) in said extended position.