End-of-content mechanism

Abstract

The present invention provides a drug injection device () for delivering multiple doses of drug, comprising: a housing () extending along a main axis, a dose expelling mechanism comprising a piston rod () configured to move relative to the housing () from a first position to a second position to cause ejection of a dose of drug, the piston rod () extending between a proximal piston rod end and a distal piston rod end and comprising a dosing track (), the piston rod () further being movable relative to the housing () from an initial pre-use position to a final end stop position to cause accumulated ejection of a predefined total dose, a dosing track follower () fixed with respect to the housing () and adapted to travel the dosing track () during dose ejection, a dose setting mechanism operable to set the dose to be ejected by the dose expelling mechanism, electronic means () for registering a dose setting operation and for registering a dose size of an ejected dose, and a display () adapted to indicate a size of a current set dose, the electronic means () being configured to provide a first type of update of the display () responsive to dose changing operations of the dose setting mechanism, wherein the electronic means () is further configured to calculate a current accumulated dose from the dose sizes of registered ejected doses to thereby provide an updated value of a total amount of drug ejected, determine a current remaining dose by comparing the current accumulated dose and the predefined total dose, and provide a second type of update of the display () when during a dose increasing operation of the dose setting mechanism the current set dose exceeds the current remaining dose, the second type of update being different from the first type of update, and wherein the final end stop position is defined by a track end configuration of the dosing track () between the proximal piston rod end and the distal piston rod end.