SE535965C2 - Needle protection with a dead position - Google Patents

Abstract

24 ABSTRACTThe present invention discloses a needle guard (100) for protecting a needle (210) from accidental contact, comprising: a spring loaded needle shield (110) being pivotable froman open position in Which the needle shield (110) is separated from the needle (210) to aclosed position in Which the needle shield (110) is enclosing and protecting the needle(210); and a mounting base (140) having a constant spatial relationship With the needle(210) When the needle guard (100) is being used, the mounting base (140) beingmovably connected to the needle shield (110) for enabling movement between the openand the closed position; Wherein the needle shield (110) is having a passive state and anactive state, the needle shield (110) being urged towards the closed position When in theactive state. A method of manufacturing the needle guard (100) and a needle guard assembly comprising the needle guard (100), are also disclosed. To be published With Fig. 1

Description

NEEDLE GUARD TECHNICAL FIELDThe present invention relates to a needle guard arranged to shield a needle from accidental contact.

BACKGROUND The clinical utilization of a pointed hollow needle is well known in the medicalart for the administration of solutions or suspensions, such as medicaments, to a humanor animal. After puncturing of the skin and introduction of the needle tip, the content ofa syringe, typically connected to the rear part of the needle, is administered to thehuman or animal through the hollow needle. The needle has then done its duty and iswithdrawn. An unprotected withdrawn needle constitutes, however, a serious healthhazard due to the fact that it may be contaminated with e. g. infectious agents originatingfrom the patient°s blood or other body fluids, in combination with the needle tip' sinherent ability to easily penetrate skin. Hence, the medical personnel who are handlingthe withdrawn needle may acquire the corresponding disease, e. g. HIV or hepatitis, if byaccident contacting it with their skin. In order to circumvent or alleviate the healthhazards associated with such a withdrawn needle amongst other things, there has beenmuch effort devoted to the development of various kinds of needle tip protectors.

US5603699 discloses a needle guard assembly comprising a mounting baseand a jacket assembly pivotally mounted on the mounting base. The jacket assemblycomprises a shield member, a lever member and activating means. The activating meansare adapted for movement of the jacket assembly from a retracted position to a closedposition around a needle. Disadvantages of this needle guard assembly include itscomplicated construction and inherent bulkiness. The former being associated with alarge cost of production and the latter with at least an increased volume of bio-hazardwaste. Furthermore, a multi-part needle guard such as this is associated with a relativelyhigh cost of production and difficulties in its assembly.

EP0887082 A2 describes a safety cover which is pivoting around a point nearthe needle hub. The safety cover is folded forwards and to the side over the needle afterinjection and withdrawal of the needle from the skin. To assure sufficient locking force,the pivoting safety cover is provided with a locking hook mechanism that mates with the needle hub upon locking, which in turn demands the manual push of the pivoting safety cover to be sufficient to overcome the resistance of the locking hook mechanism.This force needs to be relatively high, which increases the risk of the user not to lockthe safety cover in e. g. a stressful situation. The safety cover may thus be left unlockedwhich results in a potential health hazard. Also, the needle tip is not secured until thepivoting arm has been manually pushed against the needle shaft, before which the userstill is susceptible to stung/cut.

Additional safety covers of the prior art with a construction similar to theconstruction of the safety cover described in EP0887082 A2, such as the safety coverdisclosed in US4982842, may comprise an additional looking hook mechanism thatlocks around the shaft of the needle, or only a looking hook mechanism that locksaround the shaft of the needle. The force needed to overcome the resistance of thelocking hook mechanism needs, also in these cases, to be quite high. This force is alsoapplied on the needle. The needle may therefore be broken or lost from the cooperationwith the hub. This presents a danger to the user, since the user may be stung or cut onthe broken/lost needle.

None of above described needle guards protects the needle immediately afterWithdrawal of the needle from the skin. Hence, a user may accidently come in contactwith the needle tip in the time span between the Withdrawal of the needle and theactivation of the needle guard by the user. It is well known that the patient often movesduring the painful administration of e. g. medicaments through the needle, i.e. when thecontent of the connected syringe is injected. Such a movement by the patient may thusresult in involuntary withdrawal of the needle, leaving this exposed and withoutprotection from accidental contact. It is estimated that 20 to 25% of all accidents, inwhich medical personnel gets injured by the needle during injection, is occurring duringthe actual injection of the content of the syringe.

Despite general knowledge of the problem of accidents that occur during anddue to injection of medicaments for the past l0 to 20 years, no automatic shieldingdevice of injection needles that addresses and solves this problem has yet been described.

Hence, an improved needle guard for automatic shielding of a needle during and after its employment for e. g. injection is desired.

SUMMARY It is an object of the present invention, considering the disadvantagesmentioned above, to provide an improved needle guard which automatically protects theneedle immediately after Withdrawal of the needle from the skin of a patient.

It is another object of the present invention, to provide a needle guard whichmay be mounted on a wide range of standard needles or on the assembly consisting of astandard needle and standard syringe.

It is another object of the present invention, to provide a needle guard which may be produced in one piece.These and other objects, which will appear from the following description, have now been achieved by a needle guard for protecting a needle from accidental contact,comprising: a spring loaded needle shield being pivotable from an open position inwhich the needle shield is separated from the needle to a closed position in which theneedle shield is enclosing and protecting the needle; and a mounting base having aconstant spatial relationship with the needle when the needle guard is being used, themounting base being movably connected to the needle shield for enabling movementbetween the open and the closed position; wherein the needle shield is having a passivestate and an active state, the needle shield being urged towards the closed position whenin the active state.

According to another aspect of the present invention, the needle guard may comprise ahinge structure connecting the needle shield to the mounting base for forcing the needleshield into one of either said open position or said closed position; wherein the hingestructure has a dead-center position, such that the needle shield is in the passive statewhereby it is being forced by the hinge structure from a first position into the openposition if the dead-center position has to be passed to reach the closed position, and inthe active state whereby it is being forced by the hinge structure from a second positioninto the closed position if the dead-center position has to be passed to reach the openposition.

According to yet another aspect of the present invention, the hinge structure may comprise at least one toggle joint and at least one tension member. The at least one toggle joint and the at least one tension member may be connected to the needle shield and to the mounting base.

According to yet another aspect of the present invention, the mounting basemay comprise a needle hub bore for attachment to a needle hub, from which needle hubthe needle is extending.

According to yet another aspect of the present invention, the mounting basemay be integrated with the needle hub, from which needle hub the needle is extending,such that the mounting base and the needle hub are parts of the same monolithicallyformed article.

According to yet another aspect of the present invention, the dead-centerposition may be a position in which the angle between the longitudinal extension of theneedle and the longitudinal extension of the needle shield is in the range of 45 to l70°,when the mounting base is attached to or integrated with the needle hub from which theneedle is extending.

According to yet another aspect, the needle guard may further comprise at leastone locking member extending from or forrning a part of the needle shield, wherein theat least one locking member may lockingly engage with the mounting base or anyextension or recess thereof when the needle shield is in the closed position, to lock theneedle shield in the closed position.

According to yet another aspect, the locking member may comprise at least oneslit, for allowing the needle shield to lockingly engage with the mounting base byutilization of a relatively low force.

According to yet another aspect, the needle guard may further comprise at leastone unidirectionally gated bar extending from the needle shield in the volume enclosedby the needle shield. The unidirectionally gated bar may lockingly engage with theneedle when the needle shield is in the closed position, to lock the needle shield in theclosed position.

According to yet another aspect, the unidirectionally gated bar may comprise atleast one slit, for allowing the needle shield to lockingly engage with the needle byutilization of a relatively low force.

According to yet another aspect, the force needed for the needle shield tolockingly engage with the mounting base or the needle may be less that the force bywhich the needle shield is being urged towards the closed position when in said activestate, such as the force applied by the hinge structure, when forcing the needle shieldinto the closed position, for allowing locking of the needle shield in the closed positionby the force by which the needle shield is being urged towards the closed position when in said active state, such as the force provided by the hinge structure.

According to yet another aspect, the needle guard may be monolithicallyformed as a single article when manufactured.

According to yet another aspect, the needle guard may be made of atherrnoplastic, plastic or polymeric material.

According to yet another aspect, the needle guard may be manufactured by amethod comprising the step of molding or injection molding a thermoplastic, plastic orpolymeric material.

According to yet another aspect, a needle guard assembly is providedcomprising the needle guard, a needle hub and a needle, wherein the needle guard ismounted on or integrated with the needle hub.

According to yet another aspect, a method for the manufacturing of a needleguard assembly is provided, comprising the step of press-fitting or gluing the mountingbase on the needle hub when the mounting base is provided with a needle hub bore, orthe step of press-fitting or gluing the needle in the needle hub when the mounting base is integrated with the needle hub.

Further features of the invention and its embodiments are set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects, features and advantages of which the invention iscapable will be apparent and elucidated from the following description of non-lirr1itingembodiments of the present invention, reference being made to the accompanyingdrawings, in which Fig. l is a view from the side of a needle guard in the closed position mountedby means of a mounting base on a needle hub, with a needle being locked by aunidirectionally gated bar and eXtending from the distal end of the needle hub into theinside of a needle shield and with a syringe mounted in the proXimal end of the needlehub, according to one embodiment of the invention; Fig. 2 is the needle guard of Fig. l in the open position, according to oneembodiment; Fig. 3 is a perspective view of a needle guard in the closed position, displayingan elongated slot in the needle shield, in which needle shield the needle is enclosed with eXception for the most proXimal part, according to one embodiment of the invention; Fig. 4 is a view from the side of the elongated slot of a needle guard in theclosed position with two locking members clamping around the mounting base, inwhich mounting base is provided with planar surfaces on which the locking membersmay slide when moving into the locked position, according to one embodiment of theinvention; Fig. 5 is a view from the side of a planar surface of the needle guard of Fig. 4,according to one embodiment of the invention; Fig. 6 is an expansion view of the needle guard of Fig.4, showing an expansionof the locking member as it clamps around the mounting base, according to oneembodiment of the invention; Fig. 7 is the needle guard of Fig. 6 in a position between a dead-center positionand the closed position, showing the distal hook-like end of the locking member beingin contact with the planar surface of the mounting base whereby the slit is expandedsomewhat in comparison to the same slit of the needle guard of Fig. 4 and 6, accordingto one embodiment of the invention.

Figs. 8A, 8B, 8C and 8D, are cross sectional views of needle shields in theclosed position with a needle enclosed in the volume of each needle shield illustratingvarious embodiments of elongated slots; Fig. 9 is a cross sectional view of a needle shield with one unidirectionalygated bar which is extending inwards into the volume of the needle shield and providedwith one slit close to the attachment point, according to one embodiment of theinvention; Fig. 10 is a cross sectional view of a needle shield with two unidirectionalygated bars extending inwards into the volume of the needle shield and towards eachother, each bar being provided with one slit close to the attachment point, according toone embodiment of the invention; Fig. 11 is a side-ways expansion view of a hinge structure comprising onetoggle joint, which toggle joint is comprising two leg portions connected at a togglejoint knee, and one tension member of a needle guard in the closed position, accordingto one embodiment of the invention; Fig. 12 is displaying the hinge structure of the needle guard of Fig. 11 in thedead-center position, according to one embodiment of the invention; Fig. 13 is displaying the hinge structure of the needle guard of Fig. 11 and 12 in the open position, according to one embodiment of the invention; . Fig. 14 is a side-ways expansion view of a hinge structure, comprising onetogg1e joint, which togg1e joint is comprising two 1eg portions connected at a togg1ejoint knee, and a V-shaped tension member with a press member at the point of the V inthe dista1 end of the V-shaped tension member, of a need1e guard in the open position,according to one embodiment of the invention; Fig 15 is a view from the side of a mounting base, hinge structure and a part ofa need1e shie1d provided with a locking member that c1amps around the mounting basein the c1osed position, according to one embodiment; Fig. 16 is an expansion view from the side of the e1ongated s1ot of a need1eshie1d provided with a s1it protecting s1ot in which the s1it of a unidirectiona11y gated barresides whereby the s1ot can not be brought in contact with the need1e, according to oneembodiment; and Fig. 17 is a view from the top of a need1e guard in the open position showing aneed1e hub bore provided with four s1ots to mate with corresponding protrusions of a need1e hub when mounted therein, according to one embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiments of the present invention wi11 be described in more detai1be1owwith reference to the accompanying drawings in order for those ski11ed in the art to beab1e to carry out the invention. The invention may, however, be embodied in manydifferent forms and shou1d not be construed as 1imited to the embodiments set forthherein. Rather, these embodiments are provided so that this disc1osure wi11 be thoroughand comp1ete, and wi11 fu11y convey the scope of the invention to those ski11ed in the art.The embodiments do not 1in1it the invention, but the invention is on1y 1imited by theappended patent c1aims. Furthermore, the termino1ogy used in the detai1ed descriptionof the particular embodiments i11ustrated in the accompanying drawings is not intended to be 1imiting of the invention.

Embodiments of the present invention wi11 now be described be1ow withreference to Figs.1 to 17. Reference to various parts of the drawings are done by numbers according to the tab1e be1ow. number part 100 needle guard110 needle shield 115 elongated slot116 slit protecting slot120 hinge structure121 toggle joint122 leg portion123 toggle joint knee124 tension member125 press member130 unidirectionally gated bar131 slit 132 locking member140 mounting base141 needle hub bore210 needle 220 needle hub310 syringe The needle guard 100 essentially comprises a unique, novel, inventive andadvantageous combination of a spring loaded needle shield 110, a mounting base 140and means for connecting the needle shield 110 to the mounting base 140. The needleshield 110, Which may be shaped as a rod or have any other elongated shape, ispivotably movable in relation to the mounting base 140 from an open position to aclosed position. The mounting base 140 is not movable in relationship to the needle 210When the needle guard is used, i.e. it is having a constant spatial relationship With theneedle 210. The needle shield 110 is connected to the mounting base 140 by movablemeans for connection around Which the needle shield 110 may pivot. Such movablemeans for connection may be a hinge structure 120 or any other movable means forconnection as known in the art. The movable means for connection may furthercomprise or be closely located to a resilient part, such as a spring or a tension member124. When a safety mechanism of the needle guard 100 is activated by a user, i.e. Whenthe needle shield 110 is brought to an active state, the force applied by the resilient parturges the needle shield 110 to a closed position in Which the needle shield 110 isenclosing and protecting the needle 210. In the corresponding passive state, the resilientpart may or may not urge the needle shield 110 to an open position in Which the needleshield 110 is separated from the needle 210. In the open position, and typically also in the passive state, the needle 210 may be used for e. g. injection of medicaments.

The movement of the needle shield 110 may typically occur via a dead-centerposition of the hinge structure 120. The user°s activation of the safety mechanism, i.e.transition from passive to active state, may thus be achieved by movement of needleshield 110 towards closed position just past the dead-center position. The mounting base140 is configured for being connected to or integrated with the needle hub 220 of,typically, a standard needle hub-needle assembly. The resulting needle guard assemblymay advantageously be used in various applications, for example, medical applicationsor applications wherein toxic compositions are transferred via syringes connected to theneedle 210. In the open position, the needle shield 110 is remotely positioned in relationto the needle 210 so that the latter may be used for, for example, withdrawing liquidmedicaments into a syringe connected to the needle 210 and injecting these into apatient. In the closed position, the needle shield 110 is surrounding or enclosing theneedle 210 to such an extent that it can not be accidently touched by a user. A user maymanually activate the safety function of the needle guard 100 by moving, directly orindirectly via additionally thereto connected parts, the needle shield 110 from the openposition towards the closed position and just past the dead-center position. The needleshield 110 then enters the closed position, or is in an active state from which it willautomatically enter the closed position and thereby protect the needle 210 fromaccidental contact when not hindered by any foreign object, such as the outer surface ofa patient. Preferably, the needle guard 100 also comprises a locking mechanism, whichlocks the needle shield 110 in the closed position so that it may not, or only with greatdifficulty, be returned to the open position. The force applied by the hinge structure 120may, in collaboration with the locking mechanism of the needle guard 100, thus lock theneedle shield 110 in the closed position without the need of any applied extemal force.In embodiments where the needle guard 100 is provided with a locking mechanism, thehinge structure 120 is preferably arranged such that it forces the needle shield 110 intothe closed position with a force greater than the force needed for the locking mechanismof the needle guard 100 to lock the needle shield 110 in the closed position. The lockingmechanism of the needle guard 100 may comprise one or several locking members 132or one or several unidirectionally gated bars 130, or any other suitable lockingmechanism known in the art The locking mechanism of the needle guard 100 may alsocomprise one or several locking members 132 in combination with one or severalunidirectionally gated bars 130, without or in combination with any other suitablelocking mechanism known in the art. A user may typically use a needle guard assembly comprising the needle guard 100 in accordance with a three step procedure, as exemplified for the following medical application: (i) the needle shield 110 is in openposition when the user penetrates the skin of a patient with the needle 210, (ii) the useractivates the safety function by manually moving the needle shield 110 passed the dead-center position whereby the needle shield 110 is set in an active state and may contactthe skin of the patient, (iii) the user injects a medicament through the needle 210, and(iv) the user withdraws the needle 210 from the patient whereby the needle shield 110automatically enters the closed position to protect the needle 210.

The needle guard 100 of the invention automatically, without the need of anyadditional act by the user, protects the needle 210 immediately after Withdrawal of theneedle from the skin of a patient. This is a highly advantageous feature of the needleguard 100 of the invention as the needle 210, if accidently released from the skin of thepatient during step iii, would be left exposed and thus possess a great health hazard.Similar needle protection systems of the prior art are not automatic in this meaning and do require a manual activation by the user after step iii.

The needle shield 110 The needle shield 110 may be an elongated structure of various forms adapted,as known in the art, for fully or partly enclosing the needle 210 in its inner volume. Atleast the tip and the immediately adj acent part of the needle 210 may thereby not bepossible to reach, either by accident or voluntarily. The needle shield 110 may beadapted for allowing a sideways entry of the needle 210. For example, by beingprovided with an elongated slot 115 formed longitudinally along the length thereof.When the needle shield 110 is moved from the open to the closed position, the needle210 is passing through the slot 115 to be essentially enclosed by the inner volume of theneedle shield 110. The width of the elongated slot 115 may be such that facile entry ofthe needle 210 can occur. For example the ratio between the width of the slot 115 andthe diameter of the needle may be 1 to 10, such as 1.1 to 5, or preferably 1.5 to 3. Whenin the closed position, the lower part of the needle shield 110 may be in contact with theneedle hub 220 or the mounting base 220, such that the needle 210 in its entire length isenclosed by the needle shield 110. The lower part of the needle 210, i.e. the part of theneedle 210 which is closer to the needle hub 220, may or may not be enclosed by theneedle shield 110 when in closed position. Preferably, at least the tip of the needle 210and 80% of the length of its shaft may be enclosed by the needle shield 110 when inclosed position. The needle shield 110 may comprise one or several locking mechanisms, as further explained herein or as well known in the art, for ll accomplishment of a secure engagement with e. g. the shaft of the needle 210, the needlehub 220 or the mounting base 140, when in the closed position. The needle shield 110may thus not be retumed to the open position, which is beneficial for the safety of theneedle guard 100. The needle shield 110 may also be provided with additional elementsfor improvement of e.g. the safety, appearance or handling of the needle guard 100.Such elements include, for example, integrated ribs for improvement of the capability toresist external forces and coloration for indication of e. g. size of the needle 210.Additional elements include, for example, an absorbing pad for the absorption of bloodresidues or toxic chemicals after use and a smooth and/or suitable shaping of theexternal surface that may contact the skin of a patient after activation of the safetymechanism.

According to one embodiment, the back-side of the needle shield 110, i.e. theside opposite the side of the elongated slot 115, may be provide with one or severalelements that facilitates the manual movement towards a closed position. For example,the needle shield 110 may be provided with an extension reachable by the finger of auser. The surface may, partly or fully, be roughed or provided with ribs or the likewhich may increase the friction between the surface and the top of a finger.

According to one embodiment, the needle shield 110 may be provided with oneor several slit protecting slots 116 for placement of one or several unidirectionally gatedbars 130 therein. Such a slot has an inner volume that may extend essentiallyperpendicular to the extension of the needle shield 110. The one or several slits 131 ofthe one or several unidirectionally gated bars 130 may be located in the volume of theslit protecting slot 116. The slits 131 may preferably be located outside the plane of thepath of the needle 210 as it is moved from open to closed position. Advantages of oneor several slit protecting slots 116 include, for example, the n1inimized or eliminatedrisk of the needle 210 getting stuck on a slit 131.

According to one embodiment, the front-side of the needle shield 110, i.e. thesame side as the side of the elongated slot 115, may be provide with one or severalelements that facilitates the movement on skin. It may, for example, be curved such thatthere are no edges that contact the skin upon movement to the closed position, such aswhen withdrawing the needle 210 after injection. Its surface is preferably adapted suchthat the friction between the same and skin is low. It may, for example, be well polishedor made of a low-friction material. Advantages include a rninimized risk of malfunction of the safety mechanism of the needle guard 100. 12 The mounting base 140 The mounting base 140 may comprise means for securely fitting to and matingWith a needle hub 220. Such means may be constituted by a needle hub bore 141extending through the mounting base 140. The inner surface of the needle hub bore 141may have essentially the same shape as the outer surface of the needle hub 220 at asection thereof onto Which the mounting base 140 is fitted. The spatial extension, suchas the diameter, of the needle hub bore 141 may be slightly less than the correspondingspatial extension of the needle hub 220 at a section thereof onto Which the mountingbase 140 is fitted. When fitted on the needle hub 220, by e.g. press fitting, the mountingbase 140 is thereby securely fitted thereon and may not be moved relative the needlehub 220. The optimal difference in spatial extension of the needle hub 220 and theneedle hub bore 141 for secure press fitting is Well known to the one skilled in the art.

According to one embodiment, the needle hub bore 141 may be a conicallyshaped hole With a diameter that narroWs in the same direction as the extension of theneedle 210.

According to one embodiment, the needle hub bore 141 may be provided Withlongitudinal recesses that correspond and mate With the longitudinal protrusions ofstandard needle hubs 220. The needle hub bore 141 may be provided With, for example,2 to 5, such as 3 to 4, or 4 such recesses.

According to one embodiment, the mounting base 140 may be securely fittedto the needle hub 220 by press-fitting the mounting base 140 on the needle hub 220. Theneedle hub 220 is thereby securely fitted in, for example, the needle hub bore 141 of themounting base 140. Advantages of a press-fitted mounting base 140 include the lowercost of production in comparison to other means of connection.

According to one embodiment, the mounting base 140 may be securely fittedto the needle hub 220 by gluing. The needle hub 220 may, for example, be glued to theneedle hub bore 141 of the mounting base 140.

According to one embodiment, the mounting base 140 may be securely fittedto the needle hub 220 by Welding.

According to one embodiment, the mounting base 140 may be integrated Withthe needle hub 220. The mounting base 140 and the needle hub 220 are thus parts of thesame monolithically formed article. The needle 210 may be press-fitted or glued to the needle hub part of this integrated mounting base 140 and needle hub 220 article.

The hinge structure 120 13 The dead-center toggle function of the hinge structure 120 is so arranged that itforces the needle shield 110 with a force to one of either of two oppositely-disposedpositions, the open position or the closed position. In the closed position, the needle 210is protected by the needle shield 110. In the open position, the needle 210 is exposedand may be used to penetrate the skin of a patient. When a greater opposite externalforce is applied, such as the force applied by a user, to the needle shield 110 or anyextension thereof, in a direction from the open position and past the dead-centerposition, the hinge structure 120 snaps the needle shield 110 into the closed position,unless hindered by an external object such as e. g. the skin or clothing of a patient, justafter it has passed the dead-center position.

Above described dead-center toggle function of the hinge structure 120 may beachieved by various assemblies, such as for example spring loaded hinges or other“snap” mechanisms, well known in the art.

The hinge structure 120 may comprise one or several toggle joints 121 and oneor several tension members 124. A dead-center toggle function of the hinge structure120 may thus be achieved. The one or several toggle joints 121 may be connected tospatially closely related portions of the needle shield 110 and the mounting base 140.Each toggle joint 121 may preferably consist of two relatively rigid leg portions 122that are attached together at their ends in their longitudinal direction at a toggle jointknee 123. The toggle joint knee 123 may be flexible such that the leg portions 122 maybe moved relative each other to allow movement of the needle shield 110 betweenclosed and open position. The one or several tension members 124 may be able toresiliently stretch or expand to a lirnited amount. When stretched or expanded, a tensionmember 124 is elongated and strives to retain its original shorter length. Hence, astretched or expanded tension member 124 will impose a force in the direction oppositethe direction of the stretching or expansion. The point of attachment of a tensionmember 124 at the needle shield 110 is preferable above the point of attachment of thecorresponding toggle joint 121. The point of attachment of a tension member 124 at themounting base 140 is preferable below the point of attachment of the correspondingtoggle joint 121. A tension member 124 may preferably be mounted close to thecorresponding toggle joint 121, but preferably not so close that it may touch any part ofthe latter, whereby the intended function of the hinge structure 120 may otherwise becompron1ised. The dead-center position of the hinge structure 120 corresponds tospecific angle, the dead-center angle, between the longitudinal extension of the needle 210 and the longitudinal extension of the needle shield 110. If the angle between the 14 longitudinal extension of the needle 210 and the longitudinal extension of the needleshield 110 is less than the dead-center angle, the needle shield 110 strives toward theclosed position. If this angle is greater than the dead-center angle, the needle shield 110strives toward the open position. The dead-center angle may be in the range of 45 to170°, such as 80 to 120° or 90 to 110°. The one skilled in the art may easily configurethe hinge structure 120 to achieve a desired dead-center angle. For example, longer legportions 122 will result in an increase of the dead-center angle and moving the point ofattachment of a tension member 124 further above the point of attachment of thecorresponding toggle joint 121 will result in a decrease of the dead-center angle.

According to one embodiment, the hinge structure 120 may comprise at leastone, such as one, hinge and at least one, such as one, spring.

According to one embodiment, the hinge structure 120 may comprise onetoggle joint 121 and one tension member 124, which may be placed in close proxirnity.

According to one embodiment, the hinge structure 120 may comprise twotoggle joints 121 and one tension member 124, which may be placed in close proxirnity.The tension member 124 may be placed between the two toggle joints 121.

According to one embodiment, the hinge structure 120 may comprise onetension member 124 which is V-shaped and extending outwards so that it can be easilypressed on by a user. The distal end, i.e. the point of the V of the V-shaped tensionmember 124, may be shaped as or comprise a press member 125. The user may thenadvantageously activate the safety mechanism by pressing on the tension member 124or the press member 125 thereof with, for example, a finger of the same hand which isholding the syringe. The press member 125 is configured, as known in the art, to beeasily reached be the user and to be pressed on with a finger. Its outer surface, which theuser presses on, may be planar or slightly convex or concave. It may be equipped withgroves or elevations extending in a direction essentially perpendicular to the extensionof the needle shield 110. Such groves or elevations rninirnize the risk of the finger slipping of the press member 125 when the user is pushing it.

The locking mechanism The locking mechanism of the needle guard 100 secures the needle shield 110in closed position so that it cannot be moved back to an open position, or any otherposition where the needle 210 is exposed. Preferably, the locking mechanism isautomatically activated when the needle shield 110 enters the closed position. The force, kinetic energy or momentum provided by the hinge structure 120 as it moves the needle shield 110 into the closed position may be sufficient to activate the locking mechanism.The locking mechanism may be, for example, a part of or an extension of the needleshield 110. It may also be a recess in the needle shield 110 that a correspondingprotrusion connected to e. g. the mounting base 140 mates with in the closed position.When the locking mechanism is activated, the needle shield 110 is mechanicallyconnected to, for example, the needle 110, the needle hub 220 or the mounting base140, by the locking mechanism. The mounting base 140 may be provided with featuresor elements that enables or facilitate the locking of the locking mechanism, as known inthe art. lt may, for example be provided with a planar surface with an edge on which thelocking member 132 slides and locks around, respectively, when moved into closedposition. It may also be provided with e.g. a recess or similar, that a part of a lockingmember 132 mates with when locking.

According to one embodiment, the locking mechanism may comprise one orseveral, such as one or two, locking members 132 extending from or forming a part ofthe needle shield 110. A locking member 132 may be a hooked formed extension of theneedle shield 110. It may be resiliently bended out of its resting state upon initialcontact with the mounting base 140 in the movement towards the closed position. Uponentering the closed position, a part of the locking member 132, such as a distal hook-shaped end, may snap into a corresponding recess of the mounting base 140, or aroundan edge of the mounting base 140, and thereby lock the needle shield 110 in the closedposition.

According to one embodiment, the locking mechanism may comprise one orseveral, such as one or two, locking members 132 provided with one or several slits131. Such a slit 131 may be located at the side of the locking member 132 which isfacing the mounting base 140 when the needle shield 110 is in closed position. The slit131 may be a cut through a part, such as 10 to 95% or 25 to 75%, of the lockingmember 132 in a direction essentially perpendicular to its longitudinal extension. It maybe located near the point of attachment of the locking members 132 to the needle shield110, such as 0 to 60% or 0 to 40% of the total length of the longitudinal extension of thelocking members 132 from the point of attachment. A slit 131 may also be a cut througha part of the needle shield 110 close to the attachment point of the a locking member132. The depth or extension of such a slit 131 may be equal to or greater than the widthof the locking member 132. Advantages of one or several slits 131 include, for example,the decrease in force needed for moving the needle shield 110 into the closed position.

A locking member 132 is more easily bended out of its resting state upon initial contact 16 with the mounting base 140 When provided with one or severa1 slits 131. The risk of notachieving an automatic activation of the 1ocking mechanism, by e.g. the force providedby the hinge structure 120, is thereby minimized.

According to one embodiment, the 1ocking mechanism may comprise one orsevera1, such as one or two, unidirectiona11y gated bars 130. Such bars may beextending from the inside and within the need1e shie1d 110. Hence, such bars may beextending in the vo1ume enc1osed by the need1e shie1d 110, for example, in a p1aneessentia11y perpendicu1ar to the 1ongitudina1 extension of the need1e shie1d 110. The1ongitudina1 extension of a unidirectiona11y gated bar 130 may be in a direction from thee1ongated s1ot 115 towards the inside of the need1e shie1d 110. The ang1e between the1ongitudina1 extension of a unidirectiona11y gated bar 130 and the p1ane of the need1es210 path during movement from open to c1osed position may thus be, for examp1e, 20 to85°, such as 30 to 80° or 40 to 75°. The need1e 210 thereby initia11y contacts aunidirectiona11y gated bar 130 at a point thereof on an inwards 1eaning s1ope thereof,when the need1e shie1d is moved towards c1osed position. Preferab1y, a unidirectiona11ygated bar 130 is adapted such that it a11ows faci1e entry of the shaft of the need1e 210,i.e. to c1ose around the shaft of the need1e 210, but prevents retum of the need1e 210into any position where the need1e 210 is not contained in the inner vo1ume of theneed1e shie1d 110. The events that occur during activation of a 1ocking mechanism,comprising at 1east one unidirectiona11y gated bar 130, when the need1e shie1d 110 ismoved towards an into the c1osed position, may be: (i) contact between the shaft of theneed1e 210 at a point on the surface of a unidirectiona11y gated bar 130 which is facingthe e1ongated s1ot 115; (ii) the unidirectiona11y gated bar 130 is resi1ient1y bending awayfrom the force impressed by the shaft of the need1e 210 so that the shaft s1ides inwardson the inwards 1eaning s1ope thereof; (iii) the shaft reaches the dista1 end of theunidirectiona11y gated bar 130, which resi1ient1y returns to its initia1 configuration, i.e.its re1axed state, and traps the need1e 210 in the need1e shie1d 110. The distance betweenthe dista1 end of a unidirectiona11y gated bar 130 in its re1axed state and the dista1 end ofanother opposite1y p1aced unidirectiona11y gated bar 130 in its re1axed state, or the innersurface of the need1e shie1d 110, is preferab1y 1ess than the diameter of the shaft of theneed1e 210.

According to one embodiment, the 1ocking mechanism may comprise one orsevera1, such as one or two, unidirectiona11y gated bars 130 provided with one or severa1s1its 131. Such a s1it 131 may preferab1y be 1ocated at the side of the unidirectiona11ygated bar 130 facing the need1e 210 when moved towards c1osed position. A s1it 131 17 may be located anywhere along the extension of the unidirectionally gated bar 130 fromits attachment point at the needle shield 110 to the point where the needle 210 is firstcontacting the unidirectionally gated bar 130 when moved into closed position. A slit131 may thus be located on the bar such that the needle 210 never contacts it from itsinitial contact point with the bar, to the point where the bar traps the needle inside theneedle shield 110. The slit 131 may be a cut through a part, such as 10 to 95% or 25 to75%, of the unidirectionally gated bar 130 in a direction essentially perpendicular to itslongitudinal extension. lt may be located near the point of attachment of theunidirectionally gated bar 130 to the needle shield 110, such as 0 to 50% or 0 to 40% ofthe total length of the longitudinal extension of the unidirectionally gated bar 130 fromthe point of attachment. Advantages of one or several slits 131 include, for example, thedecrease in force needed for moving the needle shield 110 into the closed position. Aunidirectionally gated bar 130 is more easily bended out of its resting state upon initialcontact with the needle 210 when provided with one or several slits 131. The risk of notachieving an automatic activation of the locking mechanism, by e.g. the force providedby the hinge structure 120, is thereby minimized.

According to one embodiment, the locking mechanism may comprise one orseveral, such as one or two, unidirectionally gated bars 130 extending from the sameinner side of the needle shield 110 and towards the opposite inner side of the needleshield 1 10.

According to one embodiment, the locking mechanism may comprise one orseveral, such as one or two, pairs of unidirectionally gated bars 130. Theunidirectionally gated bars 130 of each pair may be extending from the opposite innersides of the needle shield 110 and towards each other. The distal ends may contact eachother in the relaxed state, or the distance between these ends may preferably be less than the diameter of the needle 210, when in the relaxed state.

Materials and manufacturing The needle guard 100, or separate parts thereof, may be made of a suitablematerial such as, for example, a thermoplastic, plastic or polymeric material. Suitablematerials for accomplishment of inherent resiliency in e. g. hinge structure 120,unidirectionally gated bar 130 or locking member 132 are well known in the art.Examples of such suitable materials include, but is not lin1ited to, polypropylene (PP),high-density polyethylene (HDPE), polyan1ide (PA) and acrylnitrile-butadiene-styrenecopolymer (ABS). Preferably, a material such as polypropylene (PP), which allows for 18 the manufacturing of the needle guard 100 as a monolithically formed single article, isselected. Preferably, the therrnoplastic, plastic or polymeric material has a suitablecombination, for its intended purpose, of tenacity, rigidity, fatigue resistance, elasticity,and creep deformation resistance. The selection of a suitable thermoplastic, plastic orpolymeric material may easily be made by the one skilled in the art. The one skilled inthe art may also perform standard experiments in order to screen a range oftherrnoplastic, plastic or polymeric materials, Whereby a suitable material may beselected on the basis of the results of such experiments. The manufacturing of needleguard l00 of the invention, or a needle guard assembly comprising needle guard l00,may comprise one or several steps selected from the group of steps consisting of:provision of a thermoplastic, plastic or polymeric material as starting material for needleguard l00; molding or injection molding a thermoplastic, plastic or polymeric materialinto one monolithically formed needle guard l00, Which may or may not comprise theneedle hub 220; and mounting needle guard l00 on needle hub 220 or the needle 2l0 inneedle hub 220 by, for example, press-fitting or gluing mounting base l40 to needle hub220 or the needle 2l0 to needle hub 220.

According to one embodiment, the needle guard l00 is made of atherrnoplastic, plastic or polymeric material, as known in the art. An advantage of theuse of a therrnoplastic, plastic or polymeric material for the construction of the needleguard l00, in comparison to e.g. metal, is the greater freedom of variation of variousdetails of the same. For example, a plastic needle guard l00 may be more convenientlymolded than the corresponding metallic article. Another advantage includes thepossibility to colour-code a plastic needle guard l00, for example according to theneedle size. Yet another advantage of a plastic or polymeric needle guard l00 is thehigher chemical inertness and/or resistance, in comparison to e. g. metal, towards e.g.corrosion. Yet another advantage of needle guard l00 of the invention, like a plastic orpolymeric needle guard l00, is that it may be molded and produced in one functionalpiece, i.e. it does not have to be assembled by the combination of more than oneseparate article like other corresponding devices of the prior art. Hence, a reduction in the cost of production is resulting.

In the claims, the term “comprises/comprising” does not exclude the presenceof other elements or steps. Furthermore, although individually listed, a plurality ofmeans, elements or method steps may be implemented by e. g. a single unit or processor.

Additionally, although individual features may be included in different claims, these 19 may possibly advantageously be combined, and the inclusion in different claims doesnot imply that a combination of features is not feasible and/or advantageous. Inaddition, singular references do not exclude a plurality. The terms “a”, “an”, “first”,“second” etc do not preclude a plurality. Reference signs in the claims are providedmerely as a clarifying example and shall not be construed as limiting the scope of the claims in any Way.

Claims (13)

1. A needle guard (100) for protecting a needle (210) from accidental contact,comprising: a spring loaded needle shield (110) being pivotable from an open position in which saidneedle shield (110) is separated from said needle (210) to a closed position in whichsaid needle shield (110) is enclosing and protecting said needle (210); and a mounting base (140) having a constant spatial relationship with said needle (210)when said needle guard (100) is being used, said mounting base (140) being movablyconnected to said needle shield (110) for enabling movement between said open andsaid closed position; agg a hinge structure (120) connecting said needle shield (110) to said mounting base ( 140)for forcing said needle shield (110) into one of either said open position or said closedposition, said hinge structure (120) is comprising at least one toggle ioint ( 121) and atleast one tension member (124), said at least one toggle ioint (121) and at least onetension member ( 124) being connected to said needle shield (110) and to said mountingbase (140) wherein said needle shield (110) is having a passive state and an active state, said needle shield(110) being urged towards said closed position when in said active state, said hinge structure ( 120) has a dead-center position, such that said needle shield (1 10)is in said passive state wherebv it is being forced bv said hinge structure (120) from afirst position into said open position if said dead-center position has to be passed toreach said closed position, and in said active state whereby it is being forced bv saidhinge structure (120) from a second position into said closed position if said dead-centerposition has to be passed to reach said open position, and wherein said dead-center position is a position in which the angle between thelongitudinal extension of said needle ( 210) and the longitudinal extension of said needleshield (110) is in the range of 45 to 170°, when said mounting base (140) is attached toor integrated with said needle hub (220) from which said needle (210) is extending. 42. The needle guard (100) according to any one of the preceding claims, wherein saidmounting base (140) comprises a needle hub bore (141) for attachment to a needle hub(220), from which needle hub (220) said needle (210) is extending. ä; The needle guard (100) according to an-yeoneefeclaims 149-3, wherein saidmounting base (140) is integrated with said needle hub (220), from which needle hub(220) said needle (210) is extending, such that said mounting base (140) and said needlehub (220) are parts of the same monolithically formed article. 111. The needle guard (100) according any one of the preceding claims, furthercomprising at least one locking member (132) extending from or forrning a part of saidneedle shield (110), wherein said at least one locking member (132) is lockinglyengaging with said mounting base (140) or any extension or recess thereof when saidneedle shield (110) is in said closed position, to lock said needle shield (110) in said closed position. SQ. The needle guard (100) according to claim Jfi, wherein said locking member (132)is comprising at least one slit (131), for allowing said needle shield (110) to lockingly engage with said mounting base (140) by utilization of a relatively low force. 9§. The needle guard (100) according to any of the preceding claims, further comprisingat least one unidirectionally gated bar (130) extending from said needle shield (110) inthe volume enclosed by said needle shield (110), said unidirectionally gated bar (130)lockingly engaging with said needle (210) when said needle shield (110) is in said closed position, to lock said needle shield (110) in said closed position. 101. The needle guard (100) according to claim QQ, wherein said unidirectionally gatedbar (130) is comprising at least one slit (131), for allowing said needle shield (110) to lockingly engage with said needle (210) by utilization of a relatively low force. llå. The needle guard (100) according to any one of claims li to 101, wherein theforce needed for said needle shield (110) to lockingly engage with said mounting base(140) or said needle (210) is less that the force by which said needle shield (110) isbeing urged towards said closed position when in said active state, for allowing lockingof said needle shield (110) in said closed position by the force by which said needle shield (110) is being urged towards said closed position when in said active state. 122. The needle guard (100) according to any one of the preceding claims, being monolithically formed as a single article when manufactured. | lêfi. The needle guard (100) according to any one of the preceding claims, being made of a thermoplastic, plastic or polymeric material. 14_1_1. A method for the manufacturing of a needle guard (100) according to any one ofclaims 1 to 1-3Q, comprising the step of molding or injection molding a therrnoplastic, plastic or polymeric material. l-SQ. A needle guard assembly, comprising a needle guard (100) according to any one of claims 1 to 113m, a needle hub (220) and a needle (210), wherein said needle guard(100) is mounted on or integrated with said needle hub (220). léß. A method for the manufacturing of a needle guard assembly according to claiml-SQ, comprising the step of press-fitting or gluing said mounting base (140) on saidneedle hub (220) when said mounting base (140) is provided with said needle hub bore(141), or the step of press-fitting or gluing said needle (210) in said needle hub (220)when said mounting base (140) is integrated with said needle hub (220).