The present invention relates to a drive mechanism for a medicament delivery device, comprising a plunger rod (54) arranged to act on a stopper (28) arranged in a medicament container (16) a compression drive spring (58) operably connected to said plunger rod (54) and capable of applying a force on said plunger rod (54) a spring guide (78) arranged coaxial with, and radially outside, said compression drive spring (58), capable of preventing buckling of said drive spring, wherein said spring guide (78) comprises a resilient force element (86) capable of applying a force on said medicament container (16).本發明有關用於藥物輸送裝置之驅動機構,包含柱塞桿(54),被配置來作用在塞子(28)上,該塞子被配置在藥物容器(16)中;壓縮驅動彈簧(58),可操作地連接至該柱塞桿(54),且能夠將力量施加在該柱塞桿(54)上;彈簧導引件(78),與該壓縮驅動彈簧(58)同軸向配置、及徑向地配置在該壓縮驅動彈簧外側,能夠防止該驅動彈簧的屈曲;其中該彈簧導引件(78)包含能夠將力量施加在該藥物容器(16)上之回彈力元件(86)。10‧‧‧外殼12‧‧‧近側端14‧‧‧遠側端16‧‧‧藥物容器24‧‧‧窗口27‧‧‧藥物輸送構件屏蔽件28‧‧‧塞子30‧‧‧中心通道32‧‧‧藥物輸送構件防護件34‧‧‧近側端壁面36‧‧‧中心通道38‧‧‧支臂40‧‧‧溝槽44‧‧‧裂口48‧‧‧突出部份50‧‧‧返回彈簧52‧‧‧動力單元102‧‧‧凹部104‧‧‧安全蓋106‧‧‧移除器
