Sub-assembly of a medicament delivery device and a medicament delivery device

Abstract

A sub-assembly of a medicament delivery device is presented, where the sub-assembly includes a plunger rod that is biased, a main body arranged on the plunger rod, and a coupling member movable relative to the main body, where the main body includes a first locking element, the coupling member includes a second locking element, and where the first locking element and the second locking element are configured to be releasably engaged with each other such that the coupling member is prevented from moving relative to the main body.

1 . A sub-assembly of a medicament delivery device, the sub-assembly comprising:
 a plunger rod;   a main body extending longitudinally to partially surround an outer surface of the plunger rod, where the main body comprises a flexible arm that is directly and releasably connected to the outer surface of the biased plunger rod; and   a coupling member axially fixed, partially surrounding, and rotatable relative to an outside surface of the main body such that the outside surface of the main body is between the outer surface of the plunger rod and an inner surface of the coupling member when the coupling member rotates from a first position to a second position, where the inner surface of the coupling member confines the flexible arm in a locking engagement with the outer surface of the plunger rod to prevent axial movement of the plunger rod when the coupling member is in the first position,   wherein the main body comprises a first locking element and the coupling member comprises a second locking element having a protrusion extending radially inward from a surface of the coupling member,   wherein rotation of the coupling member from the first position causes the first locking element to engage with the protrusion such that the second locking element and first locking element are releasably engaged with each other such that the coupling member is prevented from rotating to the second position, and   wherein movement of the coupling member to the second position allows the flexible arm to disengage from and unlock the plunger rod.   
     
     
         2 . The sub-assembly of  claim 1 , wherein the first locking element is longitudinal tab extending in the proximal direction. 
     
     
         3 . The sub-assembly of  claim 2 , wherein the tab comprises a proximal half that extends radially outward and then inward to form an arc. 
     
     
         4 . The sub-assembly of  claim 3 , wherein a distance between the arch of the proximal half and the central longitudinal axis is larger than the distance between all other portions of the tab and the central longitudinal axis. 
     
     
         5 . The sub-assembly of  claim 1 , wherein the first locking element comprises two longitudinal tabs extending in the proximal direction and that are oppositely arranged relative to a central longitudinal axis of the main body. 
     
     
         6 . The sub-assembly of  claim 1 , wherein the plunger rod comprising an outer surface, an open distal end and a closed proximal end, where a biasing member extends into the open distal end to bias the plunger rod in a proximal direction. 
     
     
         7 . The sub-assembly of  claim 1 , wherein the surface of the coupling member is part of circumferential recess. 
     
     
         8 . The sub-assembly of  claim 7 , wherein the first locking element comprises a longitudinal tab extending in the proximal direction and having a proximal end rotatably positioned with in the recess. 
     
     
         9 . The sub-assembly of  claim 1 , wherein the coupling member comprising an outer surface having a radial protruding ledge. 
     
     
         10 . A medicament delivery device comprising:
 a first sub-assembly including a proximal housing comprising an inside surface; and   a second sub-assembly comprising:   a plunger rod;   a main body extending longitudinally to partially surround an outer surface of the plunger rod, where the main body comprises a flexible arm that is directly and releasably connected to the outer surface of the biased plunger rod; and   a coupling member axially fixed, partially surrounding, and rotatable relative to an outside surface of the main body such that the outside surface of the main body is between the outer surface of the plunger rod and an inner surface of the coupling member when the coupling member rotates from a first position to a second position, where the inner surface of the coupling member confines the flexible arm in a locking engagement with the outer surface of the plunger rod to prevent axial movement of the plunger rod when the coupling member is in the first position,   wherein the main body comprises a first locking element and the coupling member comprises a second locking element having a protrusion extending radially inward from a surface of the coupling member,   wherein rotation of the coupling member from the first position causes the first locking element to engage with the protrusion such that the second locking element and first locking element are releasably engaged with each other such that the coupling member is prevented from rotating to the second position, and   wherein movement of the coupling member to the second position allows the flexible arm to disengage from and unlock the plunger rod.   
     
     
         11 . The medicament delivery device according to the  claim 10 , wherein the inner surface of the housing engages with the first locking element such that the first locking element and the second locking element are disengaged when the first sub-assembly is connected to the second sub-assembly. 
     
     
         12 . The sub-assembly of the medicament delivery device according to  claim 11 , wherein the first locking element extends in an axial direction from the main body, then extends radially outwards in an arch, and then extends radially inwards so that a free end of the first locking element is engaged with the second locking element to prevent the coupling member from rotating relative to the main body. 
     
     
         13 . The medicament delivery device according to  claim 12 , wherein a distance between the arch and a central axis of the main body is larger than a distance between the central axis and other portions of the first locking element, and larger than an outer radius of the coupling member. 
     
     
         14 . The medicament delivery device according to  claim 10 , wherein the main body includes a rib which divides the main body into a proximal section and a distal section, and wherein the coupling member is arranged on the proximal section, and a fixed end of the first locking element is arranged on the distal section. 
     
     
         15 . The medicament delivery device according to  claim 10 , wherein the protrusion has a ramp-shaped first surface which extends inwards from an inner surface of the second locking element that engages and bends the first locking element and a wall-shaped second surface which extends orthogonally from the inner surface of the second locking element, for fixing the first locking element relative to the coupling member. 
     
     
         16 . The medicament delivery device according to  claim 10 , wherein the coupling member comprises a closed loop at an outer proximal end thereof, where the protrusion is situated within the closed loop, and wherein the protrusion combined with a profile of the closed loop prevent the coupling member from rotating relative to the main body. 
     
     
         17 . The medicament delivery device according to  claim 10 , wherein the main body further includes a biasing member guide which is fixed to the coupling member and a distal cap in relation to which the coupling member is rotatable. 
     
     
         18 . The medicament delivery device according to  claim 10 , wherein the coupling member comprising an outer surface having a radial protruding ledge and the inside surface of the first sub-assembly comprises a protrusion projecting radially inward. 
     
     
         19 . A sub-assembly of a medicament delivery device, the sub-assembly comprising:
 a plunger rod;   a main body extending longitudinally to partially surround an outer surface of the plunger rod, where the main body comprises a flexible arm that is directly and releasably connected to the outer surface of the biased plunger rod; and   a coupling member axially fixed, partially surrounding, and rotatable relative to an outside surface of the main body, where the coupling member comprises a closed loop at an outer proximal end thereof and rotates from a first position to a second position, where an inner surface of the coupling member confines the flexible arm in a locking engagement with the outer surface of the plunger rod to prevent axial movement of the plunger rod when the closed loop member is in the first position,   wherein the main body comprises a first locking element having a flexible proximal end and the coupling member having a second locking element comprising the closed loop and a protrusion extending radially inward from a surface of the closed loop,   wherein rotation of the closed loop from the first position causes the flexible proximal end of the first locking element to engage with the protrusion such that the second locking element and first locking element are releasably engaged with each other and the closed loop is prevented from rotating to the second position, and   wherein movement of the closed loop to the second position moves the inner surface of the coupling member from confinement with the flexible arm such that the flexible arm disengages from and unlocks the plunger rod.   
     
     
         20 . The sub-assembly of  claim 19 , wherein the coupling member comprising an outer surface having a radial protruding ledge.