The invention refers to a shuttering mechanism (1) for controlling translation of a longitudinally moveable component (2) within a housing (4), the shuttering mechanism (1) comprising at least one fixed shutter (3) attached to or integrated with the housing (4) and at least one moving shutter arm (7) moveable between at least one locking position and at least one unlocking position, wherein at least one resilient arm (5) is associated with the longitudinally moveable component (2), the resilient arm (5) having a dog (6) resiliently biased towards the fixed shutter (3), wherein the moving shutter arm (7) is arranged alongside the fixed shutter (3), wherein at least one fixed protrusion (3.1 to 3.n) is arranged on the fixed shutter (3) at least one of them arranged for engaging the dog (6) so as to prevent translation of the longitudinally moveable component in a proximal direction (P), wherein at least one moving protrusion (7.1 to 7.n) is arranged on the moving shutter arm (7), at least one of them ramped in a manner to disengage the dog (6) from the at least one of the fixed protrusions (7.1 to 7.n) and/or to prevent engagement of the dog (6) to the fixed protrusion (7.1 to 7.n) when the moving shutter arm (7) is in the unlocking position, wherein the moving shutter arm (7) is arranged to allow engagement of the dog (6) with the fixed protrusion (7.1 to 7.n) in the locking position.本發明係有關於一種用以控制可縱向移動組件(2)在殼體(4)內之平移的擋門機構(1)，該擋門機構(1)包含附著或整合於該殼體(4)的至少一固定擋門(3)以及可在至少一上鎖位置與至少一開鎖位置之間運動的至少一活動擋門臂(7)，其中至少一彈性臂(5)與該可縱向移動組件(2)關聯，該彈性臂(5)有向該固定擋門(3)彈性偏壓的一止擋(6)，其中該活動擋門臂(7)配置於該固定擋門(3)旁邊，其中在該固定擋門(3)上配置至少一固定凸部(3.1至3.n)，該等固定凸部(3.1至3.n)中之至少一經配置成可接合該止擋(6)以便防止該可縱向移動組件在近端方向(P)平移，其中在該活動擋門臂(7)上配置至少一活動凸部(7.1至7.n)，該等活動凸部(7.1至7.n)中之至少一經製作成有斜坡而可在該活動擋門臂(7)處於該開鎖位置時使該止擋(6)脫離該等固定凸部(7.1至7.n)中之該至少一及/或防止該止擋(6)與該固定凸部(7.1至7.n)接合，其中該活動擋門臂(7)經配置成在處於該上鎖位置時允許該止擋(6)與該固定凸部(7.1至7.n)接合。
