| 摘要 |
The invention is directed to a drive mechanism for use in a drug delivery device having a cartridge (140), the mechanism comprising a base element (30), a toothed piston rod (120) movable from a first retracted position corresponding to a full cartridge to a second extended position corresponding to an empty cartridge, wherein the piston rod (120) is guided within and movable relative to the base portion (30), and a drive gear (110) having a pinion (114), which is rotatably held in the base element (30) and in meshed engagement with the toothed piston rod (120), wherein the toothed piston rod (120) comprises multiple rigid rod pieces (121) which are connected by hinges (122), and a drive spring (130), which is fixed to the base element (30) with one end and fixed to the drive gear (110) with another end and which exerts a force or torque to the drive gear (110) for rotating the drive gear (110) relative to the base element (30), which rotation results in a movement of the toothed piston rod (120). The drive spring (130) is charged during manufacture or assembly, wherein the energy stored in the drive spring (130) is sufficient to move the piston rod (120) from the first to the second position. The invention is also directed to a drug delivery device. |
