Medicament delivery device sub-assembly

A medicament delivery device comprising:

• a sub-assembly comprising:
• a housing;
• a propellant source contained in and axially moveable relative to said housing;
• and
• a button axially moveable relative to said housing, at least a part of said button being disposed axially rearwardly of a part of said propellant source;
• wherein the button includes one or more radially flexible blocking members, and the button is moveable between a first axial position in which the one or more radially flexible blocking members are radially restrained by the housing in a radially inward position that limits rearward axial movement of the propellant source, and a second axial position in which the one or more radially flexible blocking members are movable from the radially inward position to a radially outward position by a rearwardly axial force acting on the one or more radially flexible blocking members and permit rearward axial movement of the propellant source relative to the button and the housing;
• wherein the rearwardly axial force is created by a vapor pressure following release of a propellant from the propellant source;
• and
• a syringe connected to the sub-assembly, wherein the syringe includes a barrel for containing a medicament, the barrel having an outlet at a front end, and a stopper axially moveable in the barrel.

A sub-assembly for a medicament delivery device, the sub-assembly comprising:

• a housing;
• a propellant source contained in and axially moveable relative to said housing;
• and
• a button axially moveable relative to said housing, at least a part of said button being disposed axially rearwardly of a part of said propellant source;
• wherein the button includes one or more radially flexible blocking members, and the button is moveable between a first axial position in which the one or more radially flexible blocking members are radially restrained by the housing in a radially inward position that limits rearward axial movement of the propellant source, and a second axial position in which the one or more radially flexible blocking members are able to flex to a radially outward position and permit rearward axial movement of the propellant source relative to the button and the housing;
• wherein the housing includes a rear housing and a front housing, and axially rearward movement of the propellant source relative to the housing causes a retraction biasing member to delatch, wherein the delatched retraction biasing member urges the rear housing axially rearwardly relative to the front housing;
• wherein the retraction biasing member is delatched when latch heads are moved from a radially inward position to a radially outward position.