Sanofi
Drive mechanism of a drug delivery device

Abstract:

A drive mechanism of a drug delivery device for dispensing of a dose of a medicament, includes an elongated housing extending in an axial direction, a piston rod to operably engage with a piston of a cartridge to displace the piston in axial distal direction, a drive sleeve rotatably supported in the housing at least in a dose incrementing direction against the action of a spring element, and a ratchet mechanism to rotatably fix the drive sleeve relative to the housing. A first ratchet body has a first and a second ratchet element to alternately engage with a toothed profile of a second ratchet body. One of the first and second ratchet bodies is operably engaged with the housing and wherein the other one of the first and second ratchet bodies is operably engaged with the drive sleeve.