| 摘要 |
The present invention relates to a pen type drug injection device (1; 101) with drive mechanism, comprises a housing (4, 5; 104, 105), a dose dial member (6; 106), a drive member (8; 108) engaging a lead screw (9; 109), a first clutch (18; 118) rotationally coupling the drive member (8; 108) and the housing in a coupled state and allowing relative rotation between the drive member and the housing in a de-coupled state, a second clutch (19; 119) rotationally coupling the drive member and the dial member in a coupled state and allowing relative rotation between the drive member and the dial member in a de-coupled state, and a nut (11; 111) coaxially arranged between the drive and the dial member and splined or keyed to the drive as well as threadedly engaged to the dial member, such that it moves axially on the drive member during dose setting but not during dose dispensing, and such that it eventually abuts an end stop on one of the drive or dial member, thereby limiting movement of the nut and preventing setting of a dose larger than the amount of drug remaining in the cartridge. |
