AUTO-INJECTOR Russian patent published in 2017 - IPC A61M5/20 A61M5/315 A61M5/32 

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely to injection devices, and in particular, to auto-injectors. Auto-injector for administering a dose of a liquid medicament contains an elongate tubular case and carrier subassembly. Carrier subassembly comprising a tubular carrier slidably arranged inside the case. Carrier adapted to contain a syringe with a hollow injection needle, drive spring and plunger for forwarding load of the drive spring to a stopper of the syringe. Syringe is lockable for joint axial translation with the carrier. Drive spring acts between the carrier and the plunger. Plunger in the initial state is locked to the carrier by a ramped engagement to the carrier and by being prevented from rotating out of this ramped engagement, depending on a relative longitudinal position of the carrier in the case. Plunger is arranged to be released for rotating out of the ramped engagement upon the needle reaching at least, nearly a predefined injection depth, on translation of the carrier in the proximal direction for advancing the needle beyond a proximal end of the auto-injector.

EFFECT: invention has a mechanism for unlocking the plunger, which is especially reliable and efficient method of starting injection drug after the needle reaching an injection depth, excluding so called wet injection, id est medicament leaking out the needle, which is a problem in conventional auto-injectors, where both needle insertion and injection are achieved by pushing on the stopper.

25 cl, 27 dwg