An assembly for a drug delivery device (1) is provided comprising a housing (3), a cartridge holder (2) releasably connectable to the housing (3), a resilient member (10), and an interaction member (14) which is configured to mechanically cooperate with the resilient member (10) and with the cartridge holder (2). The resilient member (10) is configured to rotationally bias the interaction member (14). The assembly has a locked state where the cartridge holder (2) is connected to the housing (3), the cartridge holder (2) being obstructed from movement with respect to the housing (3), and an unlocked state where the connection between the cartridge holder (2) and the housing (3) is released, the cartridge holder (2) being freely moveable with respect to the housing (3). For switching from the unlocked state into the locked state, the cartridge holder (2) is brought into mechanical cooperation with the interaction member (14), the cartridge holder (2) is rotated in a first direction with respect to the housing (3), the interaction member (14) thereby being rotated in the first direction such that the interaction member (14) mechanically cooperates with the resilient member (10) and such that a rotational force exerted on the interaction member (14) by means of the resilient member (10) is overcome for switching the assembly from the unlocked state into the locked state. Furthermore, a drug delivery device (1) is provided.提供一種供藥物輸送裝置用之組件(1),其係包含殼體(3)、可解除地連接至該殼體(3)的匣支架(2)、回彈構件(10)、以及經建構成可與該回彈構件(10)氶與該匣支架(2)機械合作的互動構件(14)。該回彈構件(10)係經建構成可旋轉偏壓該互動構件(14)。該組件有鎖定狀態,在此該匣支架(2)係連接至該殼體(3),該匣支架(2)相對於該殼體(3)的運動有阻撓,以及解鎖狀態,在此係解除該匣支架(2)與該殼體(3)的連接,該匣支架(2)對於該殼體(3)可自由移動。為了由該解鎖狀態切換至該鎖定狀態,使該匣支架(2)與該互動構件(14)機械合作,該匣支架(2)對於該殼體(3)在第一方向旋轉,該互動構件(14)從而在該第一方向旋轉使得該互動構件(14)與該回彈構件(10)機械合作以及藉此克服用該回彈構件(10)施加於該互動構件(14)的旋轉力而使該組件由該解鎖狀態切換至該鎖定狀態。再者,一種藥物輸送裝置(1)已提供。