| 摘要 |
<p>A drive mechanism for an injection device is disclosed in which piston means are selectively driven to expel medicament from within a medicament cartridge. The drive mechanism comprises a drive means (270), first means (278) associated with the drive means, second gear means (274) being moveable between a first position in wich only movement along its longitudinal axis is permitted and a second position in which the second gear means (274) is free to rotate about the longitudinal axis, the piston means (280) being associated with the second gear means (274), a housing (276) within which the first gear means (278) and the second gear means (274) are constrained for movement, and baissing means (282) located between the housing (276) and second gear means (274) to bias the second gear means (274) to the first position.</p> |
