AUTOMATIC REMOVER OF PISTON ROD Russian patent published in 2001 - IPC

FIELD: medical fertilizers; applicable in dosed injection of drug from changeable cartridge. SUBSTANCE: syringe has a body accommodating cartridge holder and proportioner. The latter is used for setting and injection of dose by successive moving of piston rod for piston forcing into cartridge. Proportioner has a threaded spindle and nut member engageable with spindle. Dose is set with the help of relative rotation of spindle and nut member which results in nut member motion over spindle. Position of nut member on spindle indicates how far piston rod moves. Relative rotation of spindle and nut is located when proportioner is not actuated for dose setting. Access to cartridge holder is effected by opening of cover connected to the body and engageable with proportioner so that locking of nut member in its position on spindle is released when cover is opened and motion of cover opening is transmitted to mechanism of piston rod withdrawal. EFFECT: provided replacement of cartridge without syringe disassembly into its components and in any position of piston. 9 cl, 8 dwg