The various embodiments herein provide a mobile medical pump having a tubular cartridge unit, with a piston inserted in the cartridge and engaging an inner diameter of the cartridge, a case housing having an opening for inserting the cartridge, an infusion line may be connected to the case and a piston rod within the case housing, the piston rod having a permanent magnet at a first end and a threaded opening at an opposite end engaging a rotatable translation screw. The piston rod is set at a preprogrammed position, inserting a charged cartridge into the case, causes the magnet end of the piston rod to securely contact a steel plate embedded in the piston, such that translation of the piston rod by the translation drive system expels liquid from the cartridge and holding the piston rod motionless will hold the piston motionless, preventing any discharge of liquid from the cartridge. FIG.1 is selected.
