Automatic needle apparatus

An automatic needle device attachable to an injection device comprising:

• a housing element having distal and proximal ends;
• the proximal end of the housing element having a connector adapted for attachment to the injection device;
• a needle assembly at least partly within the housing element, the needle assembly having a needle extending from the distal end of the needle assembly;
• a needle guard having distal and proximal ends, the needle guard being positioned in the distal end of the housing element and movable from a first extended position to a retracted position to a second extended position, the needle guard covering the needle in the first and the second extended positions and exposing the needle in the retracted position;
• the needle guard being biased by a biasing device in a distal direction and being retracted to the retracted position upon contact of the distal end of the needle guard with a surface;
• the biasing device comprising a spring having distal and proximal ends;
• a locking mechanism, the locking mechanism locking the needle guard in the second extended position when the needle guard, under the influence of the biasing device, moves to the second extended position;
• and
• the spring distal end pushes against a locking element proximal surface, the locking element distal surface pushing the needle guard proximal end, the locking element further comprising one or more locking protrusions engaging an interior surface within the housing when the needle guard moves to the second extended position, whereby the needle guard is locked in the second extended position;
• and wherein the one or more locking protrusions slide within one or more corresponding grooves within the interior surface of the housing element, the one or more grooves each having a slot at the distal end of the one or more grooves, each slot receiving the one or more locking protrusions when the needle guard moves to its second extended position.