Injection device with an improved triggering mechanism

The invention relates to an injection device comprising a housing (3), a needle guard (20), an injection drive mechanism for driving a plunger within the container (5) and including o a plunger rod (31); o an injection spring (34) for biasing the plunger rod; o a retaining member (33), the retaining member and the plunger rod having corresponding latching features for retaining the plunger rod in its proximal position against the action of the injection spring, in an initial state of the injection device; and o a trigger member (35) for preventing the release of the latching features in the initial state of the device, the trigger member being axially displaceable by the needle guard (20) for releasing the latching features. The trigger member (35) and the housing (3) comprise corresponding locking features (79, 139) in mutual releasable engagement for maintaining the trigger member (35) in its blocking position, and wherein said locking features are designed to be released by the needle guard (20) when movin