Injection device

An injection device comprising:

• a housing;
• a carrier disposed within the housing for holding a syringe that has a needle at one end;
• a needle sleeve located within the housing and being axially moveable with respect to the housing between an extended position and a retracted position;
• a biasing element configured to bias the needle sleeve towards the extended position;
• and
• a locking mechanism configured to lock the needle sleeve in the extended position after an injection of a medicament by the injection device, the locking mechanism comprising (i) a first locking member provided on and projecting from the carrier and (ii) a second locking member comprising a deflectable arm provided on the needle sleeve and moveable between a relaxed position and a deflected position;
• wherein the housing includes an inwardly projecting boss configured to engage the second locking member and configured to move the second locking member into the deflected position as the needle sleeve is moved to the retracted position;
• wherein the first locking member is out of engagement with the second locking member when the second locking member is in the deflected position;
• and
• wherein the second locking member blocks the first locking member when the second locking member is in the relaxed position and the needle sleeve is in the extended position to prevent movement of the needle sleeve back into the retracted position.