Dose mechanism for an injection device for limiting a dose setting corresponding to the amount of medicament left

摘要

A mechanism for preventing setting of a dose, which exceeds the amount of a medicament in a reservoir in an injection device. The device comprises a threaded piston rod, a limiter and a driver. The three elements are arranged such that during dose setting, the limiter is moved towards an end-of-contend position, wherein dose setting is limited. The invention comprises an accumulative and a non-accumulative embodiment. The invention further relates to a mechanism for prevention ejection of a dose exceeding the set dose.

主权项

1. A mechanism for preventing setting of a dose which exceeds the amount of a medicament in a reservoir in an injection device, wherein a dose is set by rotating a dose setting member of a dose setting mechanism, the mechanism comprising:
a piston rod having a threaded outer surface, wherein the piston rod rotates and translates axially forward during expelling of medication from the reservoir; a limiter that prevents the setting of a dose which exceeds the amount of medication in a reservoir in the device, the limiter defining a passage for the piston rod; a driver defining a passage for the limiter, the driver being coupled to the dose setting member such that rotation of the dose setting member during dose setting causes the driver to rotate; andwherein the limiter is coupled to the driver and the piston rod such that relative rotation between the driver and the piston rod during dose setting causes the limiter to move towards a stopping position.