| 主权项 |
1. An auto-injection device for setting and expelling set doses of a liquid drug, comprising:
a housing defining a distal end and a proximal end, the housing adapted for receiving a cartridge so that liquid drug is expellable through a connected needle at the distal end of the housing, dose setting structure comprising a dose setting device configured for rotation by a helical movement relative to the housing, an expelling mechanism comprising a spring drive configured for automatically expelling a set dose from a held cartridge upon activation, an activation button activateable for enabling a set dose to be expelled, and a release spring providing a force that urges the activation button towards the activateable position,wherein the auto-injection device defines a latch comprising a latch geometry coupled to the activation button and a cooperating retaining geometry coupled to the dose setting device, the latch being configured to retain the activation button in the activated position against the force of the release spring when the activation button has been activated,wherein the activation button protrudes from the proximal end of the housing and is axially moveable between an activateable position and an activated position, and the dose setting device is threadedly coupled relative to the housing so that it performs a helical movement away from a zero dose position during setting of a dose and returns by a helical movement to the zero dose position as the set dose is expelled,wherein:when the dose setting device assumes its zero dose position, the cooperating retaining geometry assumes a predefined axial position relative to the housing to enable cooperation between the cooperating retaining geometry and the latch geometry as the activation button assumes its activated position, andwhen the dose setting device assumes any other position than the zero dose position, the cooperating retaining geometry assumes an axial position which prevents cooperation between the cooperating retaining geometry and the latch geometry for retaining the activation button in its activated position. |
