ASSEMBLY FOR PREVENTING UNINTENDED ACTIVATION OF A MEDICAMENT DELIVERY DEVICE

An assembly for a medicament delivery device (1), for preventing unintended activation of the medicament delivery device (1), comprising: a housing (3) having a proximal end and a distal end, wherein the proximal end has a proximal end opening (6), and a delivery member cover (17) configured to move axially from an extended position in which it extends from the proximal end opening (6) to a retracted position in which it is moved further into the housing (3), wherein the delivery member cover (17) has a radially flexible first arm configured to extend axially towards the distal end of the housing (3). The housing (3) has an interior outer wall and an interior inner wall forming a radial space configured to receive the first arm when the delivery member cover (17) is in the retracted position. One of these walls has a guide surface, wherein the first arm is configured to cooperate with the guide surface when the delivery member cover (17) is moved towards the retracted position, wherein the other one of the walls has a radial stop surface arranged further away from the proximal end than the guide surface, wherein the guide surface is configured to cause the first arm to flex radially with a first amount that allows the first arm to move into the radial space in case the delivery member cover (17) is moved towards the retracted position with a first axial velocity that is lower than a threshold value, and wherein the guide surface is configured to cause the first arm to flex radially with a second amount larger than the first amount so that the first arm is deflected towards and collides with the radial stop surface in case the delivery member cover (17) is moved towards the retracted position with a first axial velocity equal to or higher than a threshold value.