A drive assembly for a drug delivery device (1) is disclosed. The drive assembly is connectable with a cartridge holder (2) and comprises a housing (3), a piston rod (17), the piston rod (17) being movable in a distal direction for drug delivery, and a guide nut (4), the guide nut (4) being rotatable relative to the housing (3) around an axis of the assembly and provided for guiding the piston rod (17). A locking means (9) is provided which is enabled to take an engaged state in which the locking means (9) is engaged with the guide nut (4) in order to prevent rotation of the guide nut (4) and to take a disengaged state in which the locking means (9) is disengaged from the guide nut (4) in order to allow rotation of the guide nut (4). Moreover, a coupling means (14) is provided, the coupling means (14) being rotatable relative to the housing (3) around the axis of the assembly for interaction with the locking means (9) in order to change between the engaged state and the disengaged state of the locking means (9).揭示一種用於藥物輸送裝置(1)之驅動組件。該驅動組件可與一藥匣固持件(2)連接以及包含一殼體(3)，一活塞桿(17)，該活塞桿(17)在遠端方向可移動用以藥物輸送，以及一引導螺帽(4)，該引導螺帽(4)對於該殼體(3)可以繞該組件之一軸線旋轉以及配置成可引導該活塞桿(17)。提供一鎖定構件(9)，能夠使該鎖定構件(9)處於一接合狀態，此時該鎖定構件(9)與該引導螺帽(4)接合以便防止該引導螺帽(4)旋轉，以及能夠使該鎖定構件(9)處於一脫離狀態，此時該鎖定構件(9)與該引導螺帽(4)脫離以便允許該引導螺帽(4)旋轉。此外，提供一耦合構件(14)，該耦合構件(14)對於該殼體(3)可以繞該組件之該軸線旋轉用以與該鎖定構件(9)互動以便使該鎖定構件(9)在該接合狀態與該脫離狀態之間互換。
