A spring assisted drug delivery device (80 90 100) is provided comprising a housing (4) and a lead screw (22) having a longitudinal axis a distal end and a proximal end that is rotatably fixed during dose setting and dose delivery and axially moveable in a dista l direction relative to the housing. The device further comprises a drive nut (23) threadedly engaged and screwable along the lead screw threaded shaft and a number sleeve (24) threadedly engaged with the housing (4) to be screwable relative to the housing (4). A dial link (25) is connected with the drive nut (23) and axially moveable and rotatably fixed relative to the driv e nut (23) and an inner sleeve (29) is threadedly engaged with the number sleeve (24) the inner sleeve (2) being axially moveable and rotatably fixed relative to the housing (4). A mid body (20) is axially fixed inside of the housing (4). A spring (82 92 102) is provided that assists a user of the device during a dose administration step.
