The auto-injector consists of a front unit connected to a rear unit, wherein the front unit contains a syringe holder with a syringe coaxially sliding between injecting and secure positions within an activating element preloaded via an ejection spring to secure a trigger button through a stopper located in the rear unit.
The rear unit contains a syringe pusher with a plunger managed via a controller coaxially moved by an injection spring to the front unit upon activating the trigger for injecting medication. After the injection, the activating elements revert to allow the controller to release the syringe which moves into to secure position with the syringe holder and the plunger by the ejection spring.
When the syringe enters a safe position, the controller moves by the injection spring between the activating element and the syringe holder to prevent the syringe from sliding toward the injection side.