Novo Nordisk A/S
A PREFILLED INJECTION DEVICE WITH CLEANING CHAMBER

Abstract:

The invention relates to an injection device comprising an End-of-Content mechanism. The End-of-Content mechanism comprises a piston rod (10) being driven forward by a rotatable piston rod guide (20), a driver (50) attached to a dose setting tube (30) and an End-of-Content tube (40). The End-of-Content tube is moved axially forward during dose setting a distance which correlates to the size of the dose being set. When the accumulated set and ejected dose equals the injectable amount initially available in the cartridge (3), the End-of-Content tube engages a lock mechanism provided in the piston rod guide and the driver engages a stop surface on the End-of-Content tube. Once the End-of-Content mechanism is locked, no further dose can be set and the piston rod guide cannot be rotated. In order to provide a proper engagement between the piston rod guide and the driver, the End-of-Content mechanism is released during dose expelling.