AU2007253481B2 — An injection device with mode locking means

USPTO Abstract

An injection device comprising a housing, a dose setting member being operable to set a desired dose, a piston rod adapted to cooperate with a piston to cause a set dose to be expelled, and mode locking means. The mode locking means is adapted to be in a first extreme position and in a second extreme position. When the mode locking means is in the first extreme position the piston rod is prevented from cooperating with the piston, and when the mode locking means is in the second extreme position the dose setting member is prevented from being operated to set a dose. The mode locking means is adapted to be in the first extreme position during dose setting and the second extreme position during injection of a set dose. It is ensured that the liquid drug is not inadvertently expelled during dose setting and that blood or other body fluids is not sucked into the injection device during injection. Furthermore, inadvertent changing of the set dose during injection is prevented. The mechanism can readily be applied to injection devices which are not provided with a scale drum.