Pen-type drug injection device with a dose-limiting nut that prevents a higher dose from being set than the amount of remaining drug

摘要

The present invention relates to a pen-type drug injection device (1; 101) having a drive mechanism, which comprises a housing (4, 5; 104, 105), a dose dial member (6; 106), a lead screw ( 9; 109) and the drive member (8; 108) engaging with 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 decoupled state. The first clutch (18; 118), and the second clutch (19;) which rotationally connects the drive member and the dial member in a connected state and allows relative rotation between the drive member and the dial member in a decoupled state. 119) and a nut (11; 111) which is adapted to move axially on the drive member during dose setting rather than during dose dosing, and finally it is The drive member so that it abuts one end stop of the dial member, thereby limiting the movement of the nut and preventing setting a dose greater than the amount of drug remaining in the cartridge. It is disposed concentrically between the dial members, and is spline-connected or key-connected to the drive member and screw-engaged to the dial member.