INJECTION DEVICE COMPRISING LOCK NUT Russian patent published in 2012 - IPC A61M5/20 A61M5/315 

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely injection devices comprising a dose setter and an injection mechanism. The injection device for drug dose introduction comprises a body, a dose setter, an injection mechanism, a dosing tube and a blocker. The dose setter enables setting a desired dose and comprises a swing dose setting head. Actuation of the dose setter enables energy accumulation in a spring-loaded element. The injection mechanism comprises a piston rod interacting with a piston introduced into a cartridge containing the delivered drug to deliver the pre-set delivered drug dose from the cartridge through the injection device. The injection device is actuated with release of energy pre-accumulated in the spring-loaded element when setting the dose. The dosing tube is connected with the piston rod by coupled threads created therein and on the piston rod, and axially movable relatively to the body in the proximal direction when setting the dose and in the distal direction when introducing the set dose. The blocker is designed to prevent translational motion of the dosing tube in the distal direction relatively to the body when setting the dose, in the form of a lock nut fixed from axial motion relatively to the body and blocked from rotation relatively to the body when setting the dose and rotating relatively to the body when injecting the set dose. The lock nut and the dosing tube are connected by the coupled threads.

EFFECT: invention provides more accurate position control of the piston rod, stops motion of the piston rod at high accuracy, minimises risk of failure of the injection device during injection, as well as enables easy return of the piston rod into an initial position after cartridge replacement.

13 cl, 15 dwg