Assisted injection device for injecting a composition contained in a medical container

An assisted injection device for injecting a composition contained in a medical container, comprising:

• a body configured to receive the medical container in a fixed position relative to the body,
• a spring-loaded piston rod translationally movable inside the body along a spring axis, between a proximal rest position and a distal operative position wherein the piston rod engages a stopper of the medical container and pushes the stopper in the medical container,
• a lever pivotably mounted on the body about a first pivot axis orthogonal to the spring axis at a first distance from the spring axis, comprising an actuation zone configured to be directly pressed on by a user, said actuation zone being opposite the first pivot axis relative to the spring axis, at a second distance from the spring axis, and
• a selective blocking system coupled to the lever by a second pivot axis orthogonal to the spring axis,
• the lever being pivotable between a rest position wherein the selective blocking system engages the piston rod to prevent any translational movement of the piston rod and a second position wherein the selective blocking system releases the piston rod to allow the piston rod to move toward the distal operative position under the spring force.