PISTON FOR CARTRIDGE AND PISTON ROD FOR DEVICE FOR MEDICATION DELIVERY Russian patent published in 2015 - IPC A61M5/315 A61M5/24 

FIELD: medicine.

SUBSTANCE: group of inventions relate to medical equipment, namely to devices for medication delivery. Piston for cartridge for device for medication delivery contains at least one circular sealing surface, radially contacting with internal side of cartridge wall, distal surface for restricting volume of cartridge, which receives medication, and surface, receiving axial effort, made with possibility to receive plunger of device for medication delivery, which applies axial effort, in order to move piston in distal direction relative to side wall. Surface, receiving axial effort, contains multitude of centring elements, projecting from surface, receiving axial effort, towards plunger. Centring elements have external shape and geometry, which coincide with respective plunger socket. Centring elements, which have arc-like shape in plane, parallel to surface, receiving axial effort, are located and aligned by circumference of imaginary circular or ring structure. At least one centring element is cone-shaped. Plunger of drive mechanism of device for medication delivery contains butt end surface, made with possibility of contact with surface of said piston, which receives axial effort, with piston being located in sliding way in medication-containing cartridge. Butt surface contains at least one receiving socket, made with possibility of receiving multitude of centring elements, projecting from piston surface, receiving axial effort. Receiving socket has round or ring shape, corresponding to alignment by one line of centring elements, located on circumference of imaginary ring or circular structure on piston surface, receiving axial effort. Shape and geometry of receiving socket coincide with shape and geometry of piston centring element in such a way that butt end nearly completely rests against piston surface, receiving axial effort. Cartridge for device for medication delivery contains in fact cylindrical case of cartridge, providing volume for medication reception, and at least partially filled with medication, and sealed by means of said piston. Device for medication delivery for distribution of preliminarily set quantity of liquid medication, made with possibility of receiving said cartridge, additionally containing mechanism, which includes said plunger.

EFFECT: group of inventions is aimed at prevention of transmission of effort, directed not to the centre, towards cartridge piston, as well as aimed at provision of improved dosing accuracy.

12 cl, 8 dwg