A NEEDLE INSERTION MECHANISM FOR AN INJECTION DEVICE WITH AN IMPROVED IMPACT RESISTANCE

Needle insertion mechanism comprising a housing and a needle holder holding a needle. The needle holder is linearly guided to be moved along the needle axis. A slider is linearly guided and transversally moveable to the needle axis from a first to a second slider position, wherein the slider is coupled to the needle holder in the first slider position keeping the needle holder in a retracted position against the bias of a spring acting on the needle holder. In the second slider position the needle holder is decoupled from the slider and moved into the inserted position by the spring. A releasable coupling arrangement arranged between the slider and the housing which is coupled when the slider is in the first slider position thereby keeping the slider in the first position against an actuation threshold which must be surpassed to decouple the slider for movement into the second position.