Patent ID: 7361160

Claim:
A device for injecting an active substance, comprising an injection needle, a housing, a receptacle for the active substance accommodated in a sliding sleeve slidable relative to the housing, a syringe piston displaceable in the receptacle for expelling the active substance, and a needle protecting device displaceable relative to the housing, wherein, during a skin penetration of the injection needle, the needle protecting device remains in a substantially constant position relative to the housing and in the process a spring element is stressed, wherein, after the removal of the injection needle from the skin, the spring element pushes the needle protecting device into an advanced position in which the needle is covered and the needle protecting device is prevented from retracting by a distal end of the sliding sleeve blocking the needle protecting device from axially moving in the direction of the housing; wherein during the skin penetration, the sliding sleeve is displaced within the housing from a retracted position to an advanced position and the needle protecting device is automatically locked in the advanced position by a locking means operative between the needle protecting device and the sliding sleeve when the needle protecting device and the sliding sleeve are located in their advanced position; and wherein the locking means comprises at least one flexible tongue arranged on the sliding sleeve and oriented in a generally axial manner, which tongue in its relaxed state forms an axial stop with a region of the needle protecting device.