A liquid pharmaceuticals delivery device comprising a mainly cylindrical main body, a cartridge having a mainly cylindrical inner cavity with a volumetric capacity for accommodating multiple doses of a liquid pharmaceutical, the cartridge comprising a first end for receiving a plunger and a second end for liquid pharmaceutical extraction; the plunger having a circumferential portion shaped and sized to correspond to transversal section of the cartridge, the device is characterized by further comprising: A jackscrew comprising a threaded lower jackscrew and a threaded upper jackscrew integrated to each other, the jackscrew being rotatable around a primary axis of the cylindrical main body and stationary along said primary axis, A threaded plunger rod integrated to the plunger and having a thread diameter (Dp), which is smaller than the thread diameter (Ds) of spindle, corresponding to the thread diameter of the lower jackscrew, the plunger rod being in threaded communication with the lower jackscrew and moving inside the lower bearing, wherein lower bearing together with plunger rod, and lower/upper jackscrews (5, 6) stays in permanent contact with the cartridge during dose setting and delivery in order to guarantee the dosing accuracy as the force transmission to the cartridge and plunger rod is supported by the flange of lower jackscrew and the lower bearing, independent from the main body, A threaded mainly cylindrical spindle having a thread diameter (Ds), which is greater than the thread diameter (Dp) of the plunger rod, corresponding to the thread diameter of the upper jackscrew, the spindle being in threaded communication with the upper jackscrew wherein the threads on the spindle and the threads on the plunger rod are working in the same rotational direction in order to reduce the operational friction and the threads on the spindle have a pitch distance greater than a pitch distance of the threads on the plunger rod, A button engageable with the spindle, by one thereof having a recess and the other having a protrusion matching said recess along a direction parallel to the primary axis of the spindle, A resilient means normally keeping the button in a disengaged position from the spindle, wherein said recess and protrusion are kept away from each other by the resilient means, and the engaged position is available by pushing and moving the button against the force of the resilient means, A jackscrew comprising a threaded lower jackscrew and a threaded upper jackscrew integrated to each other, the jackscrew being rotatable around a primary axis of the cylindrical main body and stationary along said primary axis, A threaded plunger rod integrated to the plunger and having a thread diameter (Dp), which is smaller than the thread diameter (Ds) of spindle, corresponding to the thread diameter of the lower jackscrew, the plunger rod being in threaded communication with the lower jackscrew and moving inside the lower bearing, wherein lower bearing together with plunger rod, and lower/upper jackscrews (5, 6) stays in permanent contact with the cartridge during dose setting and delivery in order to guarantee the dosing accuracy as the force transmission to the cartridge and plunger rod is supported by the flange of lower jackscrew and the lower bearing, independent from the main body, A threaded mainly cylindrical spindle having a thread diameter (Ds), which is greater than the thread diameter (Dp) of the plunger rod, corresponding to the thread diameter of the upper jackscrew, the spindle being in threaded communication with the upper jackscrew wherein the threads on the spindle and the threads on the plunger rod are working in the same rotational direction in order to reduce the operational friction and the threads on the spindle have a pitch distance greater than a pitch distance of the threads on the plunger rod, A button engageable with the spindle, by one thereof having a recess and the other having a protrusion matching said recess along a direction parallel to the primary axis of the spindle, A resilient means normally keeping the button in a disengaged position from the spindle, wherein said recess and protrusion are kept away from each other by the resilient means, and the engaged position is available by pushing and moving the button against the force of the resilient means,