Abstract:
A single-use device for injection includes a pre-filled syringe with a front nose which supports an injection needle which is protected by a protective cap, and a syringe body which accommodates the syringe. The device further includes a joining piece with claws which can be extended radially to cover and grasp the protective cap by penetrating the cap. The syringe body includes a front section, which can be separated, that is delimited by a breakable area. The front section includes a neck that clamps the tabs of the joining piece onto the protective cap.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a single-use device for injection, comprising a pre-filled syringe which is provided with a front nose, and supports an injection needle which is protected by a protective cap, and a syringe body which accommodates the said syringe, and is provided with means for locking of the latter in rotation and in translation. 
     At present, for safety reasons, some injection devices of the above-described type comprise a protective joining piece for the cap, which also serves the purpose of facilitating removal of the protective cap. 
     These protective joining pieces, which are generally designed to be fitted on the front end of the syringe body, additionally comprise a central sleeve, which is designed to cover the protective cap, and is provided with grasping claws which are clipped onto the rear of the said cap. 
     Although in practice, protective joining pieces of this type make it possible to fulfil the required objectives, they have a major disadvantage, which consists of the fact that the central sleeve is fitted onto the protective cap by being forced, and, when this fitting takes place, it tends to push this cap rearwards during passage of the sealing neck with which the front nose of conventional syringes is conventionally provided. 
     The fact of thrusting the cap rearwards in this manner can have two detrimental consequences. In fact, firstly, it can cause damage to the end of the needle, which conventionally is stuck into the cap. In addition, it can give rise to breakage of the seal between the protective cap and the nose of the syringe, at the sealing neck of the latter. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to eliminate these disadvantages, and its main objective is to provide a device for injection which is provided with a safety system for protection of the protective cap, which permits easy removal of the latter, and is not likely to damage the needle or detract from the sealing. 
     For this purpose, the invention relates to a device for injection as described in the foregoing preamble, characterised in that: 
     it comprises a joining piece, known as a joining piece with claws, which consists of a front wall, and at least two tabs which can be extended radially, and extend longitudinally relative to the front wall, which can cover the protective cap, and are provided with at least one inner claw for grasping the said cap; 
     the syringe body has an open rear front surface which can permit introduction of the syringe, and an opposite front section, which can be separated, and is delimited by a breakable area, which is disposed such as to be positioned substantially at the front nose of the syringe which is accommodated in the said syringe body, the said section which can be separated comprising a neck which is designed to clamp the tabs of the joining piece with claws, such that the latter ensure that the protective cap is grasped; 
     the said section which can be separated and the joining piece with claws being provided with conjugated means for locking in translation and in rotation of the latter relative to one another. 
     According to the invention, and firstly, the joining piece with claws is simply positioned on the protective cap, before the syringe is introduced into the syringe body, and is actually clamped onto the said cap by radial deformation of the tabs at the neck, with which the section which can be separated is provided. 
     This solution, which consists of trapping the protective cap by means of radial deformation of the tabs of the joining piece with claws, leads to elimination of the risks of damaging the needle and breaking the seal. 
     However, in order to guarantee this absence of risks, and preferably, each grasping claw of the joining piece with claws is positioned such as to ensure that the protective cap is grasped substantially downstream from the sealing neck. 
     In addition, according to the invention, the section which can be separated constitutes a protective element which has undeniable advantages in terms of safety, and of inviolability of the protection. In addition, as a result of the locking in rotation and in translation relative to one another of this section which can be separated and of the joining piece with claws, breakage of the breakable area makes it possible to remove simultaneously the said section which can be separated and the joining piece with claws, together with the protective cap which is trapped in the latter, thus providing release directly of the injection needle. 
     It should also be noted that since the breakage of the breakable area is obtained conventionally by imparting movement of rotation to the section which can be separated, the protective cap is also rotated during this breakage, and its detachment is thus greatly facilitated. 
     According to an advantageous embodiment, the means for relative locking in rotation and translation of the joining piece with claws and of the section which can be separated comprise: 
     a plurality of longitudinal catches, which are provided on at least one of the tabs of the joining piece with claws, such as to be positioned downstream from the neck of the section which can be separated of the syringe body, when the syringe is accommodated in the latter; and 
     a plurality of longitudinal catches which are provided in the section which can be separated, downstream from the neck of the latter, such that the said neck forms a shoulder for stoppage in translation of the joining piece with claws. 
     In addition, advantageously, the longitudinal catches which are provided in the section which can be separated, are distributed around the entire periphery of the inner surface of the said section which can be separated, such as to dispense with the need to mark the relative angular positioning of the joining piece with claws and of the section which can be separated. 
     In addition, in order to facilitate by-passing of the neck, and advantageously, the longitudinal catches of each tab of the joining piece with claws are disposed on a boss, which is provided with an inclined front portion, forming a ramp which is designed to facilitate passage of the neck. 
     For the same purpose, and advantageously, the neck of the section which can be separated consists of an inner boss, provided with an inclined rear portion which forms an access ramp. 
     Additionally, in order to ensure that the protective cap is trapped satisfactorily, the neck is advantageously disposed such that it is positioned at the grasping claws of the joining piece with claws. 
     According to an advantageous embodiment, the joining piece with claws comprises four longitudinal tabs which are distributed regularly relative to the axis of the front wall, two of the said diametrically opposite tabs comprising a boss, and the two others, which are known as the grasping tabs, comprising at least one grasping claw. 
     In addition, advantageously, the grasping tabs each comprise two lateral grasping claws. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other characteristics, objects and advantages of the invention will become apparent from the following detailed description provided with reference to the attached drawings, which show by way of example a preferred, non-limiting embodiment. In these drawings: 
     FIG. 1 is a longitudinal cross-section through an axial plane, of a device according to the invention for injection, shown before it is used; 
     FIG. 2 is a perspective view of the protective sheath of this device for injection; 
     FIG. 3 is a longitudinal cross-section through an axial plane A of this protective sheath; 
     FIG. 4 is a longitudinal cross-section through an axial plane B of this protective sheath; 
     FIG. 5 is a transverse cross-section through a plane C of this protective sheath; 
     FIG. 6 is a transverse cross-section through a plane D of this protective sheath; 
     FIG. 7 is a longitudinal cross-section through an axial plane E of the locking ring of this device for injection; 
     FIG. 8 is a perspective view of this locking ring; 
     FIG. 9 is a longitudinal cross-section through an axial plane F of the claw-type joining piece of this device for injection; 
     FIG. 10 is a perspective view of this claw-type joining piece; 
     FIGS. 11 a  to  11   f  are schematic views showing the successive production steps of this device for injection; 
     FIG. 12 is a longitudinal cross-section through an axial plane of this device for injection, showing the initial step of removal of the protective cap, for the purpose of use of the said device for injection; 
     FIG. 13 is a longitudinal cross-section through an axial plane, representing the device for injection on completion of injection; and 
     FIG. 14 is a longitudinal cross-section through an axial plane representing the device for injection in the position for protection after it has been used. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The device according to the invention for injection shown in FIG. 1 comprises firstly a pre-filled syringe  1  of the conventional type, which for example is made of glass, comprising in a conventional manner a front nose  1   a , onto which there is fitted a needle  2 , and a collar  1   b  at its rear end. 
     This syringe  1  also comprises in a conventional manner a cap  3  for protection of the needle  2 , which is designed to be fitted in a sealed manner on the front nose  1   a  of the said syringe. 
     It also comprises in a conventional manner a piston  4 , which delimits the chamber filled with a dose of fluid, which contains a blind threaded bore, into which there is screwed the threaded end  5   a  of a piston rod  5 , which is provided at its opposite end with a thruster  6 . 
     According to the invention, this thruster  6  is in the form of a bowl, which has a section  6   a  with an oblique profile, for the purposes explained hereinafter. 
     The injection device according to the invention also comprises an assembly for protection of the syringe  1 , which is designed to be fully pre-assembled before the said syringe, which is initially pre-filled, is put into place in the said protective assembly. 
     This protective assembly comprises firstly a protective sheath  7 , which is shown in FIGS. 2 to  6 , consisting of two, front  8  and rear  9  tubular bodies, which are designed to be fitted one in the extension of the other. 
     The front body  8  has an inner diameter which is conjugated relative to the outer diameter of the syringe  1 , and a length which is designed to accommodate the needle  2  provided with its protective cap  3 , and is substantially 80% of the length of the syringe  1 . 
     At its rear end, this front body  8  comprises a rear section  8   a  which has a substantially ovoidal outer shape, with outer diameters which are larger than the regular outer diameter of the said front body, and is hollow on the interior, such as to comprise inner longitudinal ribs such as  10 , which define an inner diameter identical to that of the regular inner diameter of this front body  8 . 
     Each of these ribs  10  additionally has a shoulder  10   a , which delimits a rear end portion with an inner diameter which is substantially larger than the diameter of the syringe  1 . 
     On the outer side, this rear section  8   a  comprises an annular groove  11  which is delimited by a rear clip ring  12 . In addition, as shown in FIG. 5, this groove  11  is interrupted by two lugs such as  13 , which are diametrically opposite, and project radially relative to the clip ring  12 . 
     At its front end, the front body  8  comprises a front section  8   b  which can be separated, and is delimited by a breakable annular area  14 , which is positioned such as to be disposed substantially at the front nose  1   a  of the syringe  1 , when the latter has been put into place. 
     This section  8   b  which can be separated has on its interior, at its rear end, an oblique profile  15 , which forms a ramp, delimiting a rear portion which constitutes a neck  50 , with a diameter which is substantially smaller than that of the regular inner diameter of the front body  8 . 
     At the front of this rear portion, the section  8   b  which can be separated additionally comprises a plurality of longitudinal catches such as  16 , distributed on the periphery of the inner surface of the said section which can be separated, and delimiting an inner diameter which is identical to that of the said rear portion, such that the bases of the said catches define a shoulder  17  together with the front end of this rear portion. 
     Finally, with reference to this section  8   b  which can be separated, the front portion of the latter which is disposed at the front of the catches  16  has an inner diameter which is identical to the diameter which separates the base of the catches. 
     The rear body  9  has a substantially ovoidal shape, which is conjugated relative to that of the rear section  8   a  of the front body  8 , and is designed to be fitted onto the said rear section  8   a.    
     For this purpose, this rear body  9  firstly comprises an inner annular groove  18 , which is designed to accommodate the clip ring  12 . It also comprises two inner, diametrically opposite longitudinal grooves such as  19 , which can each accommodate a lug  13 , such as to ensure locking in rotation of the two bodies  8 ,  9 , the said grooves being interrupted at a short distance from the rear end of this rear body  9 , such that the latter has an inner shoulder  20  at the level of the end of these grooves  19 . 
     As shown in FIG. 7, the grooves  19  are provided according to the larger diameter of the rear body  9 , such as to minimise the thickness of the wall of the said rear body. 
     The rear body  9  additionally has two deformable tabs such as  21 , each of which is provided in a groove  19  at the rear end of the latter, and each of which is formed from a cut-out in the shape of a U provided in the wall of the said rear body. 
     At its rear end, each of these tabs  21  comprises a transverse hook  22 , which projects inside the rear body  9 . Each of these hooks comprises a substantially radial anti-return rear surface  22   a , and an oblique front surface  22   b  which forms a ramp. 
     Finally, the rear body  9  comprises a conventional finger-support outer collar  23 . 
     Secondly, the protective assembly comprises a locking ring  24 , which has a shape which is designed to be inserted in the rear body  9 , when it is presented opposite the front surface of the latter. 
     This locking ring  24 , which has a length which is designed to be inserted in the rear body  9 , is in the form of a cylindrical sleeve  25 , which is prolonged at the rear by two tabs such as  26 , which are diametrically opposite one another in the form of a sector of a cylinder. 
     Each of these two tabs  26  has firstly a rear end surface  26   a  with an oblique profile, which is complementary relative to that of the section  6   a  of the thruster  6  of the piston rod  5 . 
     Also, substantially half-way along its length, each of these tabs  26  comprises a transverse outer rib  27 , which is designed to be able to slide in one of the grooves  10  of the rear body  9 . 
     Centred on the same generatrices as the transverse ribs  27 , the cylindrical sleeve  25  of this locking ring  24  comprises two transverse ribs such as  28 , which are also designed to slide in the grooves  10  of the rear body  9 , and are provided at the front end of the said sleeve. 
     Substantially half-way along its length, and axially aligned with the aforementioned ribs  27 ,  28 , this cylindrical sleeve  25  also comprises two diametrically opposite inner ribs such as  29 , downstream from each of which the peripheral wall of the said sleeve is provided with an aperture such as  30 , which permits ejection of the undercut piece. 
     Each of these inner ribs  29  has a rear surface  29   a  with an oblique profile which forms a ramp, and an anti-return locking radial front surface  29   b.    
     Finally, downstream from the apertures  30 , and at a distance from the inner ribs  29  which is conjugated relative to the thickness of the collar  1   b  of the syringe  1 , the cylindrical sleeve  25  comprises an annular inner shoulder  31 . 
     Finally, the injection device according to the invention comprises a joining piece  32  with claws, which is shown in FIGS. 9 and 10, and is designed to cover the protective cap  3 , and to give rise to withdrawal of the latter after breakage of the breakable area  14  of the front body  8  of the protective sheath  7 . 
     This joining piece  32  with claws has a cylindrical front wall  33 , with a diameter which is designed to penetrate in the section  8   b  which can be separated, at the periphery of which there extend substantially at right-angles four separate longitudinal tabs  34 ,  35 ,  36 ,  37 , which are distributed regularly relative to the axis of the said wall: 
     two tabs  34 ,  35  which are diametrically opposite, and are each provided at their free end with two lateral claws such as  38 ,  39 , which are designed to be able to penetrate in the protective cap  3 ; and 
     two other diametrically opposite tabs  36 ,  37 , each of which has in an intermediate position along its length an outer boss such as  40 , with an outer surface provided with longitudinal catches such as  41 , which are conjugated relative to the catches  16  of the section  8   b  which can be separated. In addition, each boss  40  has a cylindrical rear portion  40   a,  which is preceded by an inclined front portion  40   b  which forms a ramp. 
     It should also be noted that, as shown in FIG. 9, when bedding-in takes place, the tabs  34 - 37  are in a substantially “open” position, i.e. they are inclined towards the exterior relative to the axis of the front wall  33 . 
     Production of the above-described device for injection, as well as the interconnection of the various units of the component elements, is explained hereinafter with reference to FIGS. 11 a  to  11   f.    
     The first step consists of introducing the locking ring  24  into the rear body  9  of the protective sheath  7 , by presenting the latter opposite the front surface of the said rear body, until the ribs  27  abut the shoulder  20  (FIG. 11 a ). It should be noted that this putting into place is permitted by the resilience of the tabs  21 , and the shape of the front surface  22   b  of the ribs  22 , which forms a ramp which allows the said ribs to be by-passed. 
     It should also be noted that when the locking ring  24  has been put into position, it is locked in rotation relative to the rear body  9 , as a result of the positioning of the ribs  27  in the grooves  19 . 
     The second step consists of introducing a spiral spring  42  partially inside the locking ring  24 , by presenting the latter opposite the front surface of the said ring, until one of its ends abuts the shoulder  31  (FIG. 11 b ). 
     The third step consists of fitting the front body  8  onto the rear body, by co-operation of the clip ring  12  with the groove  18  (FIG. 11 c ). During this operation, the spring  42  is automatically compressed between the shoulders  10   a  of the ribs  10  and the shoulder  31 . In addition, the front body  8  and the rear body are locked in rotation relative to one another, as a result of positioning of the lugs  13  in the grooves  19 . 
     On completion of these three operations which can easily be automated, a fully-assembled protective assembly is obtained, inside which there can then be introduced the pre-filled syringe  1 , as previously described. 
     Prior to this introduction, as shown in FIG. 11 d , the joining piece  32  with claws is positioned on the protective cap  3  of the syringe  1 , which at this stage is without the piston rod  5 . During this positioning, the tabs  34 - 37  of the joining piece  32  with claws are simply positioned around the protective cap  3 , without any risk of pushing the latter in, and damaging the needle  2  and/or destroying the seal. 
     The syringe  1  which is provided with the joining piece  32  with claws is then introduced into the rear body  9  of the protective sheath  7 , until the collar  1   b  is locked between the ribs  29  and the shoulder  31  (FIG. 11 e ). It should be noted that this introduction is made possible by the fact that the ribs  29  can be deformed, and owing to the ramp-type form of the rear surface  29   a  of these ribs  29 , which allows the latter to be by-passed by the collar  1   b.    
     In addition, during this introduction, the joining piece  32  with claws is clamped on the protective cap  3 , when the bosses  40  of the latter pass the level of the ramp  15  of the section  8   b  which can be separated and the neck  50 , which passage is also facilitated by the ramp-type form of the front portion  40   b  of the said bosses. 
     It should also be noted that, as shown in FIG. 1, during this clamping, the claws  38 ,  39  penetrate the protective cap  3  downstream from the glass cone which is conventionally provided on the front nose of conventional syringes  1 , and is designed to guarantee sealing. Thus, any risk of pushing in the protective cap  3  and therefore damaging the needle  2  and/or destroying the seal is eliminated. 
     When this step has been carried out, it should be noted that the joining piece  32  with claws and the protective sheath  7  are locked in rotation relative to one another, as a result of the co-operation of the respective catches  16 ,  41  of the latter. In addition, firstly, the protective cap  3  is locked in rotation relative to the joining piece  32  with claws, owing to the penetration in the latter of the claws  38 ,  39 , and secondly, this joining piece  32  with claws, the protective sheath  7  and the locking ring  24 , are also locked in rotation relative to one another, as previously explained. 
     The final step shown in FIG. 11 f  consists of rendering the piston rod  5  integral with the piston  4  in a conventional manner. This then provides an injection device which is ready to use, use of which is described hereinafter with reference to FIGS. 12 to  14 . 
     Firstly, as shown in FIG. 12, the initial step consists of breaking the breakable area  14  in a conventional manner, by subjecting the section  8  which can be separated to rotary movement, and pulling this section. During the movement, since the assembled elements (protective cap  3 , protective sheath  7 , locking ring  24 ) are locked in rotation relative to one another, the protective cap  3  is firstly made to turn, thus facilitating detachment of the latter, then the joining piece  32  with claws is locked in translation relative to the section  8   b  which can be separated, by thrusting the bosses  40  against the shoulder  17 , such that the protective cap  3  is removed simultaneously with the joining piece  32  with claws and with the said section which can be separated. 
     The injection can then be carried out in a conventional manner by means of antagonistic action on the thruster  6  and the finger-support collar  23 . On completion of the injection, as shown in FIG. 13, the profiled edge  6   a  of the thruster  6  co-operates with the profiled edge  26   a  of the tabs  26  of the locking ring  24 , causing the said tabs  26  to be deformed radially towards the interior, until the ribs  27  are released. 
     It should also be noted that since the ribs  27  are disposed in an intermediate position on the tabs  26 , the latter have a ramp to the rear of the said ribs, which makes it possible to absorb the production tolerances of the syringes  1 , and to ensure that the entire dose of fluid is delivered. 
     As shown in FIG. 14, when the injection has been completed, and force on the thruster  6  has ceased, the locking ring  24 , which is thrust by the spring  42 , is pushed back inside the protective sheath  7 , and entrains the syringe  1 , until the ribs  28  by-pass the ramp  22   b  of the ribs  22 , and are locked between the said ribs  22  and the shoulder  20 , thus preventing further use of the injection device. 
     Finally, and advantageously, the front body  8  of the protective sheath  7  is made of a translucent material, so that the syringe  1  can be seen. On the other hand, the rear body  9  of this protective sheath is made of an opaque material, so as to conceal the release mechanism from the sight of the user and the patient. 
     The locking ring  24  is made of a material which has a colour different from that of the rear body  9 , such as to make it possible to identify immediately injection devices which have already been used.