Medicament delivery device

An automatic delivery device comprising:

• an automatic delivery device housing;
• a stationary container holder fixedly attached to the automatic delivery device housing;
• a plunger rod for driving a slidable stopper of a medicament container arranged within the stationary container holder, the plunger rod comprising:
• a cylindrical member extending from a distal end to a proximal end,
• a first smooth surface provided along an exterior of the cylindrical member, the first smooth surface extending from the distal end to the proximal end of the cylindrical member,
• a second surface provided along an interior of the cylindrical member, the second surface configured to contain a plunger rod tension spring,
• the proximal end of the cylindrical member configured to operatively engage the slidable stopper of the medicament container arranged in the stationary container holder;
• and
• an activation member coaxially arranged between the stationary container holder and the automatic delivery device housing, the activation member comprising:
• a main body configured to extend from a front proximal end to a back distal end,
• a tubular portion provided near the front proximal end of the main body of the activation member,
• at least two longitudinally extending arms extending away from a distal end of the tubular portion of the main body, and
• at least one guiding element provided along at least one of the at least two longitudinally extending arms.