Patent ID: 8372031

Claim:
An injection device for manually penetrating a needle arranged to the device and automatically injecting a medicament mixture, comprising: first and second housing parts, wherein a multi-chamber container is arranged into the first housing part, and the first housing part is arranged to be manually displaced into the second housing part for mixing at least two substances arranged inside the container; a plunger rod arranged to act on a stopper arranged inside the container; a drive force mechanism configured to push the plunger rod to act on the stopper; an activation member, comprising a flexible locking mechanism releasably connected to the plunger rod for holding the plunger rod and thereby the drive force mechanism in a pre-tensioned state, and a push button protruding from the second housing part; and a locking member arranged around the activation member and axially slidable in relation to the activation member between a first position in which the locking member completely surrounds the flexible locking mechanism and a second position in which the locking member partially surrounds the flexible locking mechanism after the locking member has been axially displaced by the first housing part when the first housing part has been displaced into the second housing part; wherein the flexible locking mechanism is arranged to be released from the plunger rod only after the locking member is moved from the first position to the second position and the push button is axially moved into the second housing part, such that the flexible locking mechanism is completely out of contact with the locking member; wherein the activation member further comprises a hook mechanism that includes at least one flexible tongue arranged with an outwardly directed hook at an outer end arranged to interact with a radially holding mechanism that includes an annular ring having a circumferential ledge with a shape corresponding to the outwardly directed hook and arranged on an inner circumferential surface of the second housing part for locking the push button when the push button is depressed before the locking member is moved from the first position to the second position and thereby avoiding premature activation of the device.