Patent Publication Number: US-2022226577-A1

Title: Support structure, medicament delivery device and method of assemblying

Description:
TECHNICAL FIELD 
     The present application relates to a support structure for a medicament container for holding the medicament container in a steady state inside a medicament delivery device. 
     BACKGROUND 
     Many medicament delivery devices are developed for self-administration, i.e. a user performs the medicament delivery her-, or himself. This requires a medicament delivery device, which is as safe to use and as easy to handle as possible. In order to meet these requirements, the risk of human errors must be minimized, the number of actions needed to be performed in order to receive a dose shall be reduced, and the device must be intuitive and ergonomic to use. Thus, in order to minimize the risk of human errors, it is desirable to have the device as pre-assembled for a deliver to the user. 
     An important aspect of automatic injectors is a human aspect of handling the injector regarding how it is held during penetration, a general aim is to have the patient holding the injector in an ergonomic way that may permit the penetration and injection in different locations on the body, such as around the waist and also on the backside of the waist and/or in the buttocks of the patient. Sometimes the patient does not see the injector at those locations and need to be able to hold the injector without having to change grip. By removing the action of pushing a button or making them automatically fired, the patient is free to hold the device as he desires and feels comfortable. 
     It is considered important for the patient to receive a confirmation that the injection has been made, in particular in instances when an injector is used where the patient does not see the injector, e.g. such as around the waist and also on the backside of the waist and/or in the buttocks of the patient. In order to prevent accidental injuries after a completed injection, it is desired e.g. to lock a needle guard in an extended position safely covering a sharp injection needle. 
     There are many different devices had been developed in the last years, such as automatic injectors. On the other hand, there are manufacturing tolerances when components of the automatic injector are manufactured and assembled. It is a known problem that the automatic medicament delivery devices such as e.g. automatic injectors often comprise a medicament container or a prefilled syringe made of glass. It is known in the art that those glass syringes have manufacturing tolerances in their dimensions, which may cause different problems during assembly or use of the medicament delivery device. 
     Document W2017/191159 A1 discloses a powerpack to be used with a medicament delivery device, which power pack comprises a plunger rod and is characterized in signal initiating elements for providing information to a user of a medicament delivery device about the movement of said plunger rod, when the plunger rod sleeve has been activated to release holding elements. 
     Document US 2019/201612 A1 discloses an intermediate structure for a support structure to cooperate with a medicament container, comprising a flexible element arranged to exert a force on a distal end surface of said medicament container, wherein said intermediate structure is arranged between said flexible element in an outwardly direction in relation to a longitudinal axis when exerting a force on said medicament container. 
     Document WO2016/193355A1 discloses a syringe support for an autoinjector. The syringe support has a couple of bellow-shaped flexible portions for absorbing of the length variations of the syringe made of glass. 
     Document WO2016/120207A1 discloses an automatic medicament delivery device having a pair of arch-shaped flexible elements on a distal end of a tubular component of a drive unit. The pair of flexible elements are made for compensating of syringes length variations as they face a flange of a glass syringes to urge it forward during the assembly. This allows avoid the syringe rattling into the housing due to different length of the glass syringes and thus a breakage during a transportation and/or activation of the automatic medicament delivery device. 
     On the other hand, the glass syringes have not only length tolerances, but also a radial dimensions&#39; variation. Therefore, it is not excluded that the flexible elements might be flexed inwardly into the syringe interior and lead to a jam and breakage. 
     Document WO2019/137701A1 discloses a support structure for an automatic medicament delivery device aiming to solve this problem with undesired flexing of a length tolerance compensating elements during a contact with a syringe flange. The flexible elements in form of arched wings at a proximal end of the support structure. The flexible wings are supposed to flexibly urge the syringe in a proximal direction during assembly and/or activation for avoiding its rattling due to manufacturing tolerances. Each flexible wing is provided with an inwardly directed protrusion of a particular shape to ensure the flexing of the supporting flexible elements outwards. A drawback of this solution is an increased friction between a plunger rod surface during its proximal movement and the support structure flexible wings. Therefore, there is a need to avoid rattling of the syringe due to its urging in proximal direction and the same time do not negatively impact functionality. 
     It is also known, that manufacturing tolerance of the glass containers and glass syringes appears not only in length but also in radial dimensions. This means that the e.g. a syringe distal flanges can have a different radius between the flange surface and the syringe interior or inner chamber, thus different diameters of the syringe distal opening. Therefore, in the case of the syringe with the larger distal opening to be inserted into the automatic injector, the flexible elements for length variation compensation might be lead to flex into this opening instead of flexing outwards. Therefore, there is a need to solve this problem, and to achieve a component compensating for both, radial and length variations in size for glass components. 
     SUMMARY OF THE DISCLOSURE 
     The object of the present disclosure is to provide a medicament delivery device that is reliable and easy to use when handling and activating and easy to assembly. This is achieved by an automatic medicament delivery device with an elongated housing having a proximal end and a distal end. A medicament container is to be accommodated into the housing. The medicament container is equipped with a medicament delivery member on a proximal end and a distal end flange. A plunger rod, when released, acts on a stopper inserted in the distal end of the medicament container for start of a medicament delivery. The plunger rod is driven by a drive spring and accommodated in a support structure. The support structure supports on its outer surface a rotational member interacting with the support structure for locking and releasing of the plunger rod axial movement when the rotational member rotates. An axially movable activator for activating the medicament delivery device is inserted into the housing for interacting with the rotational member. The rotation of the rotational member releases the plunger rod axial movement in the proximal direction and locks the actuator after completion of the medicament delivery. The medicament delivery device comprising the tubular support structure having the at least one first flexible element extended in a proximal direction, provided on its outer surface with a contact member. The outer radial of the contact element dimension extends over the first flexible element outer dimension and is arranged to contact a distal end flange of the medicament container or the syringe preventing the flexing of the flexible element inwardly into the syringe interior. 
     According to a further aspect of the disclosure, to ensure that the due to manufacturing tolerances in length and in diameters of the glass container, the medicament delivery device functioning properly, an elongated support structure is used for supporting axially a distal end flange of a medicament container to be inserted into a medicament delivery device. The support comprises a tubular body having an inner dimension and an outer dimension, a longitudinal axis. The tubular body has a distal end and a proximal end. At least one first flexible element is arranged at the proximal end of the tubular body extending in a proximal direction and facing the medical container distal end. The at least one flexible element has the same outer dimension (and the same inner dimension as the tubular body. The at least one first flexible element is provided on its outer surface with a contact member which has an outer radial dimension extending over the first flexible element outer dimension and which is arranged to contact the distal end flange of the medicament container. 
     According to another aspect of the disclosure, the at least one first flexible element the support structure comprises a first front surface inclined in relation to the longitudinal axis and facing in the proximal direction. 
     According to a yet another aspect of the disclosure, the contact member comprises a second front surface extending radially in an inclined direction in relation to the longitudinal axis over the first front surface of the flexible element and facing in the proximal direction. The first surface of the flexible element and the second surface of the contact member are situated at the same angle in relation to the longitudinal axis. 
     According to a yet a further aspect of the disclosure, the first surface and the second surface are inclined at the different angles to the longitudinal axis. 
     According to another aspect of the disclosure, the first flexible element is able to flex radially only outwardly relative to the axis when brought in contact with the medicament container distal end surface of flange due to an increased total radial contact surface of the flexible element and the contact member which covers possible diameter variations of the glass syringes. 
     According to a further aspect of the disclosure the support structure further comprises a second flexible element identical in shape and dimension to the first flexible element, which extends symmetrically in the longitudinal axis direction from the tubular support structure proximal end and diametrically opposite to the first flexible element. 
     According to yet another aspect of the disclosure the contact member has one of a rectangular and a semi-spherical shape which is to be fit into a corresponding recess on an inner surface of the rotational member. 
     According to yet a further aspect of the disclosure, a drive mechanism or a second sub-assembly is used for activating an elongated medicament delivery device having a longitudinal axis and a medicament container such as a syringe with a proximal end and a distal end. The container is to be inserted into the medicament delivery device. The drive mechanism comprises a plunger rod for acting on the medicament container for delivery of a medicament within a pre-filled container. A pre-tensioned drive spring is inserted into the tubular hollow plunger rod for moving the plunger rod in the proximal direction when the plunger rod is being released for movement. A support structure accommodates the plunger rod with the drive spring inside and supports on its outer surface a rotational member interacting with the support structure for locking and releasing of the plunger rod. An activator is movable axially in a distal direction for interaction with the rotational member for its rotating; releasing the locked plunger rod with an inserted pre-tensioned driving spring and activation of the medicament delivery due a distal movement of the plunger rod urged by the pre-tensioned spring. 
     By the term automatic medicament delivery device, is herein meant a medicament delivery device adapted to deliver a medicament without a user having to press a push button or activation member, but instead only by pressing the proximal end of the medicament delivery device against the delivery site. 
     According to another aspect of the disclosure, a distal end of the tubular forms a distal end of the medicament delivery device. The tubular structure in inserted in the distal end of the medicament delivery device housing. 
     The medicament delivery device further comprising a medicament delivery member, e.g. such as an injection needle. The axially movable activator is a medicament delivery member guard to be pressed against an injection site. The medicament delivery guard comprises a guard spring biasing the medicament delivery guard in an extended position from the proximal end of the housing, when the guard spring is being released. A protective cap at the proximal end of the medicament delivery housing is attached to the activator and protecting the medicament delivery member due to friction. 
     According to yet another aspect of the disclosure, the medicament delivery device is an auto-injector and the medicament delivery member is an injection needle. The protective cap comprises a needle shield remover for removal of the needle shield form the needle simultaneously upon removal of the protective cap and thus releasing the medicament delivery member guard for proximal axial movement to the extended position. The medicament delivery device is an auto-injector, e.g. a single-dose disposable injector. 
     The medicament delivery device according to the present disclosure presents a number of advantages. There is a high degree of functionality and automation, which remove unnecessary components and actions for delivering a medicament. 
     Also an important safety aspect is met since, during withdrawal from the injection site, the tubular activation member is pushed out and covers the delivery member e.g. a needle, and also is been locked in the extended state, thereby preventing unintentional needle sticks. Furthermore, the extended radially outwards contact members of the flexible arch-shaped wings at the proximal end of the support structure provide increased the support surface for contact with the syringe flange. Thus, a compensation of the manufacturing dimensions&#39;, the variations both in length and in the inner diameter of the syringe, is achieved, rattling of the syringe is prevented and the flexible wings are able to flex only outwardly relative to a central axis. 
     According to yet another aspect of the disclosure, a method of assembling the medicament delivery device includes assembling two sub-assemblies of a proximal end and a distal end of the device. The method comprises steps of inserting a medicament delivery member shield remover into a protective cap, inserting a spring for an activator and the activator into a central axial opening of a housing from a proximal end and putting a protective cap onto the activator proximal end thus forming a first sub-assembly. 
     The method further comprises steps of inserting of a drive spring into a plunger rod and those together into a support structure central axial opening. The support structure has a tubular body and at least one first flexible element arranged at a proximal end of the tubular body. A rotational member is placed onto the support structure. Rotating of the rotational member about the axis is locking the drive mechanism components together thus forming a second sub-assembly. On the at least first flexible element is provided a contact member with a proximal surface extending in a radial direction over a contact surface of the first flexible element and arranged to contact a distal end of a pre-filled medicament container, when inserted between the first and the second sub-assemblies and ensuring that the flexible element is flexing only outwards relative to the axis A due to an enlarged total contact surface of the first flexible element and the contact member. 
     According to yet a further aspect of the disclosure, the method of assembly of the medicament delivery device has a further step of inserting a pre-filled medicament container into the first sub-assembly of the medicament delivery device from a distal end of the housing and inserting the assembled drive mechanism as the second sub-assembly thereafter from the distal end into the housing. An at least one first flexible element contacts the distal end or distal flange of the inserted pre-filled medicament container preventing its axial movement after the assembly. 
     These and other aspects of and advantages with the present disclosure will become apparent from the following detailed description and from the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following detailed description of the disclosure, reference will be made to the accompanying drawings, of which 
         FIG. 1  shows a perspective view of a first embodiment of an internal support structure of the medicament delivery device. 
         FIG. 2  shows a longitudinal cross-section of a first embodiment of an elongated medicament delivery device with an inserted syringe. 
         FIG. 3  illustrates a partial view of a tubular body of the support structure with a pair of flexible elements having contact members of a first embodiment. 
         FIG. 4  illustrates a partial view of a tubular body of the support structure with a pair of flexible elements having contact members of a second embodiment. 
         FIG. 5  shows a partial view of a tubular body of the support structure with a pair of flexible elements having contact members of a third embodiment. 
         FIG. 6  shows a partial view of a tubular body of the support structure with a pair of flexible elements having contact members of a fourth embodiment. 
         FIG. 7  shows a perspective view of the tubular support structure with an inserted plunger rod and a rotational member prior an assembling onto the support structure. 
         FIG. 8  illustrates a tubular housing of the medicament delivery device with a monitoring window and inner ribs along the housing for guiding an activator longitudinal movement. 
         FIG. 9  shows a perspective view of the activator with a central opening and two guiding grooves along its longitudinal elongated arms. 
         FIG. 10  illustrates a partial perspective view of some components included in a drive mechanism such as the rotation member placed on the support structure outer surface, an inserted into the support structure plunger rod, which is shown partly inside a syringe and in a contact with a stopper on the syringe distal end. A needle is mounted on a proximal syringe end of the syringe and surrounded by a spiral metal spring of a needle guard. 
         FIG. 11  illustrates a perspective view of a metal rod supporting a drive spring of the plunger rod and a signal generating element informing a user when the injection is completed. 
         FIG. 12  illustrates a perspective view of a fully assembled medicament delivery device with an inserted pre-filled medicament container (not visible) and ready for a transportation. 
         FIG. 13  illustrates a cross-sectional along the longitudinal axis of the medicament delivery device longitudinal view with a protective cap satiated onto the activator in a state prior to activation of the medicament delivery device. 
         FIG. 14  illustrates a cross-sectional along the longitudinal axis of the medicament delivery device longitudinal view in a state after an injection has been completed. 
     
    
    
     DETAILED DESCRIPTION 
     In the present application, when the term “distal part/end” is used, this refers to the part/end of the delivery device, or the parts/ends of the members thereof, which is/are located the furthest away from the medicament delivery site of the patient. Correspondingly, when the term “proximal part/end” is used, this refers to the part/end of the delivery device, or the parts/ends of the members thereof, which, is/are located closest to the medicament delivery site of the patient. 
       FIG. 1  illustrates, in perspective, a tubular support structure  1  is inserted into an elongated housing  3  of an exemplary medicament delivery device  10  as shown in  FIG. 2 . The tubular housing  3  has a proximal end  11  and an opposite distal end  12 . The tubular support structure  1  further comprises a tubular body  13 . The support structure  1  has a proximal end  131  and a distal end  132  along a central axis A. The distal end  132  of the support structure  1  has a larger dimension relative to the proximal end  131  and provided with a pair of flexible arms  5  extending in a proximal direction along the axis A, able to flex from and to the axis A and situated one opposite the other diametrically. In some embodiments, the distal end  132  of the support structure  1  forms a distal end  12  of the medicament delivery device  10  of this embodiment. The tubular body  13  is equipped with a pair of flexible arms  6  extending in a proximal direction along the axis A, able to flex from and to the axis A and situated one opposite the other diametrically. The flexible arms  6  of the tubular body  13  are displaced on 90° relative to the flexible arms  5  of the distal end  132 . The tubular body  13  has a central opening  27  on its distal end for insertion of some components during assembly of the medicament delivery device  10 . The proximal end  131  of the tubular body  13  is provided with a pair of flexible elements  18 , which is here e.g. an arch-shaped wings  18  extending from the tubular body  13  edge in a proximal direction parallel to the axis A one opposite the other and made integrally with the tubular body  13  by e.g. a precision moulding. Alternatively, the only one flexible element  18  in the other configuration can be used and it might be a separate component. 
     Each flexible element  18  is defined by an outer surface  181 , having the same radial dimension “D” as the rest of the tubular body  13 ; an inner surface  183 , having the same radial dimension “d” as the interior of the tubular body  13 , and an inclined in relation to the axis A front surface. The flexible elements  18  are supposed to support a distal end  19  or a flange  19  of a prefilled medicament container  17 , e.g. a syringe  17  in this embodiment (as also illustrated in  FIG. 10 ). The flexible elements  18  are able to flex radially outwardly from the axis A, when getting in a contact with the syringe  17  distal end  19 , if the syringe  17  length is a bit longer. It is known that a manufacturing length variation can be of about 3-5% of the length, that might be of about +/−1.5 to 2.5 mm for the syringes of 50 mm. During assembly for ensuring of the syringe  17  firm fixation into the medicament delivery device  10  without movability in axial direction A, the flexible elements  18  are urging it forward and due to their flexibility/deformation provide a necessary compensation for manufacturing tolerances of the pre-filled medicament container  17  or the syringe  17 . The flexibility of the elements  18  allows avoiding rattling and possible damage of the glass syringe container  17 , which is fragile. The tubular support  1  with the flexible elements  18  allows assembling of syringes with varying lengths due to manufacturing tolerances within the same housing without any gaps between the neighbouring components in axial direction. 
     At the arch-shaped element  18  highest point, in the middle of each arch-shaped flexible wing  18 , a contact member  28  is situated on an outer surface  181  of the flexible element  18 ; the outer surface  181  faces away from the axis A. In this exemplary embodiment of  FIG. 1 , there are two opposite each other flexible elements  18 , and each flexible element or flexible wing  18  is equipped with the contact member  28  extending radially from the flexible element  18  outer surface  181  and thus enlarging a contact area of the wings  18  with the oppositely situated syringe  17  distal end with a central opening and a flange  19 . This enlarged contact area of the flexible element  18  is able to compensate for a diameter variation for the glass syringe  17  central opening. This means that, if the central opening of the syringe  17  is somewhat larger, the proximal surface  29  of the contact member  28  extending radially over the dimension “D” of the proximal end  131  of the tubular body  13  (see  FIG. 4 ) would ensure contact of the flexible elements  18  in form of wings  18  in this embodiment with the distal end  19  and/or the flange  19  of the syringe  17  and would prevent the flexible elements  18  to flex inwardly and/or be led into the syringe  17  central opening. 
       FIG. 2  illustrates schematically the assembled medicament injection device  10  with a removed protective cap  30  (see  FIG. 121  and  FIG. 13 ) prior to start of the injection. A drive mechanism  2  is situated in the distal end  12  of the housing  3 . The drive mechanism  2  comprises among others the tubular support structure  1  having the tubular body  13 , a tubular hollow plunger rod  15  accommodating a first resilient member  16  in form of a drive spring  16  and been inserted into the central opening  27  of the tubular body  13 , and a rotational member  14  situated onto the outer circumferential surface  133  of the tubular body  13 . The first drive spring  16  might be placed around a metal support rod  24 . The tubular body  13  is provided with a pair of flexible elements  18  in form of two arch-shaped wings  18 . The flexible elements  18  are able to flex outwards relative to the central axis A so as to bias a syringe  17  via its distal end flange  19  in the proximal direction until its proximal end  20  is set firmly on a seat formed on an interior of the housing  3  proximal end  11 . The plunger rod  15  is arranged to move forward in the proximal direction a stopper  8  when conducting an injection. The movement of the stopper  8  can be observed thought a monitoring window  7  (as illustrated in  FIG. 8 ) or two windows in the housing  3 . The proximal end  20  of the glass syringe  17  is equipped with a medicament delivery member  4  which is in this embodiment is an injection needle  4 . The needle  4  is usually protected by a needle cover (not illustrated here) and surrounded by a delivery member guard  21 . In this embodiment, the needle guard  21  functions as an activator  21  for the medicament delivery device  10 . The activator  21  is provided with a needle guard spring  22  biasing the activator  21  in a form of the needle guard  21  in the proximal direction to an extended position as illustrated in  FIG. 2 . 
     As disclosed previously, the flexible elements  18  are provided with the contact members  28 .  FIG. 3  illustrates a first embodiment of the contact member  28 . The contact member of this embodiment has a rectangular shape and its front surface  29  facing a proximal direction is perpendicular to the axis A. The shape of the contact member  28  is adapted to be received and guided by a corresponding recess on the inner surface of the tubular rotational member  14  (visible in  FIG. 7 ). When the rotational member  14  is to be assembled onto the tubular body  13 , the flexible elements  18  are guided by the contact members  28  sliding in the recesses to flex inwardly and thus to be put onto the tubular body  13  from its proximal end  131 . The two partially shown flexible elongated arms  6  of the tubular body  13  are situated one the opposite the other on the tubular body  13  circumference  133 . 
       FIG. 4  illustrates a second embodiment of the contact member  28 , which has a trapezoidal shape, but might be a half-spherical shape (not shown) also. The front surface  28  in this case is inclined to the central axis S. The stop member  28  has a radial dimension that extends the radial dimension “D” of the proximal end  131  of the tubular body  13 . The surface  182  of the first flexible element  18  in the pair of the elements  18  faces a situated opposite the similar surface  182  of the second flexible element  18  in the pair relative the axis A, both surfaces  182  face the proximal direction and both are inclined in relation to the central axis A at the same angle. The outer surfaces  181  of the flexible elements  18  are even with the outer circumference surface  133  of the tubular body  13  proximal end  131  and have the same radial dimension “D”. The central opening  27  of the proximal end  131  of the body  13  has the inner diameter “d” which is equal to a dimension of or a distance between the inner surfaces  183  of the flexible elements  18 . 
       FIG. 5  illustrates a third embodiment of the contact elements  28  having a proximal contact surface  29  even with the inclined surface  182  of the flexible elements  18  and inclined at the same angle as the surface  182 . The contact elements  28  of the third embodiment extend radially and increase the total contact surface  182  of the flexible elements  18  with the distal end  19  of the syringe  17 . 
       FIG. 6  illustrates a fourth embodiment of the contact elements  28  with the frontal contact surfaces  29 . An inner circumference  134  of the proximal end  131  has the dimension “d”. 
       FIG. 7  illustrates partially assembled the tubular support structure  1 . The plunger rod  15  is inserted into the tubular body  13  of the support structure  1 . The rotational member  14  been put onto the outer circumferential surface  133  of the tubular body  13  from its proximal end  131 . The rotational member  14  has a pair of recesses in its inner surface interacting with and guiding the contact members  28  along the axis A during the assembly. The flexible elements  18  at the beginning of assembling are forced to flex inwardly until the contact members  28  run along the inner pair of the recesses, and when they run out of the rotational member  14 , the flexible members  18  are able to flex outwardly. On the outer surface of the rotational member  14  a number of tracks  141 ,  143  are formed for interacting with at least one inwardly extending protrusion  39  (e.g. a pair of the radially inward projecting protrusions  39  as illustrated in  FIG. 9  for this embodiment) on the distal end the activator  21 . The radially inwards extending protrusion(s)  39  is(are) adapted to be guided within the at least one track  141 ,  143  forcing the tubular rotational member  14  to rotate when the tubular activator  21  is axially moved inside the medicament delivery device  10 , when been pressed against an injection site. The radial protrusion  39  glides along the inclined track  141  into the straight portion of the straight track  143  turning the rotational member  14  along the central axis of about 35°. This movement releases the flexible arms  6  of the tubular body  13  allowing their flexing outwards, and thus the extensions  26  at the ends of the tubular body  13  arms  6 , previously situated into the recesses  25  of the plunger rod  15 , move out releasing the plunger rod  15 , that is biased by the pre-tensioned drive spring  16 , to move in the proximal direction. A pair of flexible tongues  142  of the rotational member  14  first allow the radial inwardly extending protrusions  39  to glide over due to flexing inwardly, and then, due to flexing outwardly in the initial position are locking the activator in form of the needle guard  21  in the extended position after the medicament delivery had been completed, preventing its movement in the distal direction. 
       FIG. 8  illustrates, in perspective, the tubular housing  3  of the exemplary medicament delivery device  10 . The tubular housing  3  has a proximal end  11  and the opposite distal end  12  The tubular housing  3  further comprises at least one guiding protrusion or a rib on its inner surface of the wall, preferably two protrusions or two ribs symmetrically situated in relation to the central axis A. The protrusion or protrusions in form of ribs of the housing  3  is/are adapted to interact with at least one groove  34  of the activator  21  such as the tubular shaped needle guard  21  (e.g. as in  FIG. 9 ), having preferably two symmetrical grooves  34 . The groove  34  of the tubular activator  21  is used for locking the tubular activator  21  inside the tubular housing  3 , when the tubular activator  21  is in its most proximal position, before and after an injection has been made. In an exemplary embodiment of  FIG. 8 , there are two guiding ribs, one on each side of the inner wall of the tubular housing  3 . The two recesses  40  prevent rotation of the activator  21  when moved in the distal direction. The tubular housing  3  may further comprise a container holder (not illustrated here) which is coaxially arranged and fixedly attached within the tubular housing  3  for lodging the medicament container  17  (see  FIG. 10 ). The medicament injection device  10  comprises the tubular support structure  1  forming the drive mechanism  2  as explained above, being coaxially arranged and fixedly attached to the distal end  12  of the housing  3 . 
       FIG. 9  shows a central opening  23  in the activator  21  that has a dimension allowing a needle cover remover (which is not illustrated) usually been situated into the protective cap  30  to pass through the opening  23  when a needle cover (not shown) arranged on the injection needle  4  is to be removed. The needle cover in this embodiment is removed simultaneously with the removal of the protecting cap  30  from the activator  21  proximal end. 
       FIG. 10  illustrates a number of components in the interior of the medicament delivery device  10 . The medicament delivery device  10  further comprises the second resilient member  22  or the second spring  22  is arranged in relation to the tubular activator  21  biasing it in the proximal direction from a non-activated position to an activated position. An annular proximal end of the activator  21  (as illustrated in  FIG. 9 ) extends not more than about 1.9 mm from the proximal end  11  of the housing  3 , when the medicament injection device  10  is in the non-activated state and whereby the annular proximal end of the activator  21  is extended at a predetermined distance, it might be of about 11-12 mm from the proximal end  11  of the housing  3 , when the medicament injection device  10  is in an activated state. 
     The medicament container  17  might be arranged within the container holder (not shown) and has a predetermined volume of medicament, the slidable stopper  8  and the delivery member  4 . In an exemplary embodiment of the invention, the medicament container  17  is the syringe  17  provided with the needle  4  as the delivery member  4 , however the invention should not be limited to this. The other embodiments might include a medicament cartridge, one or multi-chamber cartridge, having a membrane on its proximal end, or the like where a delivery member can be adapted to penetrate the membrane for a delivery of the medicament. 
     The best seen in  FIG. 10 , the syringe  17  proximal end or flange  19  is urged axially in the proximal direction by the pair of flexible elements  18  of the tubular support structure  1  during assembly process for avoiding axial gaps and thus, avoiding a risk of the glass syringe breakage. 
     Additionally, the medicament delivery device may be equipped with a signal-generating member  35 , as illustrated in  FIG. 11 , adapted to generate an audible and/or tactile and/or visible injection confirmation signal upon a performed medicament delivery. The medicament delivery confirmation signal is generated when the drive mechanism  2  changes state from a pre-tensioned state, wherein the first drive spring  16  is pre-tensioned within the plunger rod  15 , and the plunger rod  15  is engaged to the tubular body  13 , to a released state, wherein the plunger rod  15  is completely released from the tubular body  13  and is no longer in contact with the signal generating member  35 . In the pre-tensioned state, the plunger rod  15  is locked to the tubular body  13  by the extensions  26  on the flexible arms  6  extending radially inwards toward the central axis A and engaging the two corresponding opposite recesses  25  onto the plunger rod  15 . In the release state, after the rotational member  14  is turned about the axis A by the activator  21  of about 35°, the extensions  26  of the arms  6  move out of the plunger rod  15  recesses  25  thus realising the axial movement of the plunger rod  15  in the proximal direction for the medicament delivery. 
       FIG. 11  is a perspective view of the signal generating member  35  in relation to the plunger rod  15  and the first resilient member  16 . In the illustrated embodiment, the signal generating member  35  is an elongated u-bracket  35  adapted to enclose at least a part of the plunger rod  15  and the first resilient member  16 . The signal-generating member  35  comprises two support members  37 ,  37 ′ are adapted to rest on an annular surface on the proximal end  131  of the tubular body  13  when the drive mechanism  2  is in a pre-tensioned state. The proximal ends of the arms  36 ,  36 ′ are provided with the angled support members  37 ,  37 ′ extending in essentially radially outwards with regard to a longitudinal axis of the u-bracket  35  with is the central axis A of the injector  10 . 
     When the drive mechanism  2  is in the pre-tensioned state, the distal end of the u-bracket  35  is arranged at a predetermined distance from an inner distal surface of a tubular interior of the distal end  132  of the support body  1 . When the drive mechanism  2  is in the released state, the distal end wall  38  of the u-bracket  35  meets the distal surface of the interior the distal end  132  of the support structure  1 . The audible and/or tactile and/or visible confirmation signal is generated when the distal end wall  38  of the u-bracket  35  of the signal-generating member hits and contacts the inner distal surface of the tubular body  13  distal end  132  by a remaining force exerted by the first drive spring  16 . Thus, during the delivery procedure, when the distal end of the plunger rod  15  passes by the supporting members  37 .  37 ′, the arms  36 ,  36 ′ with the support members  37 ,  37 ′ are released and allowed to move in a radial inward direction, due to a pre-tension of the arms  36 ,  36 ′, enabling the u-bracket  35  move distally and the signal, typically an audible sound and/or a visual signal and/or a tactile signal is generated, when the u-bracket  110  hits the distal end of the tubular body  13 . In the pre-injection state, the u-bracket  35  is arranged such that the arms  36 ,  36 ′ are positioned in a space along the plunger rod  15  between the plunger rod  15  and the tubular body  13  enclosing the plunger rod  15 . The support members  37 ,  37 ′ have an extension in the radial outward direction that exceeds the radial extension of the space between the plunger rod  15  and the inner wall of the tubular body  13  to secure that the signal generating member  35  is not released prior the plunger rod  15  has moved away from between the arms  36 ,  36 ′. Alternatively, the outer distal surface of the distal transversal end wall  38  may further have a protrusion (not illustrated), adapted to be guided through an opening, typically a through hole (also not illustrated) of the distal end  132  of the support structure  1  and extends distally a predetermined distance over the outer surface of the distal end  132 . In an exemplary embodiment of the invention, the distally extending protrusion might have a bright and/or different colour than the rest of the device  10  for generating a visual signal. Thus, such protrusion will enable both a tactile and the visual signal, when the u-bracket  35  hits the distal end  132  of the support structure  1 . 
     It is however to be understood that embodiments described above and shown in the drawings are to be regarded only as non-limiting examples of the present disclosure and that may be modified within the scope of the appended patent claims.