The present invention proposes a liquid pharmaceuticals delivery device comprising a mainly cylindrical main body (1), a cartridge (3) having a mainly cylindrical inner cavity with a volumetric capacity for accommodating multiple doses of a liquid pharmaceutical, the cartridge (3) comprising a first end for receiving a plunger (7) and a second end for liquid pharmaceutical extraction. The device further comprises a jackscrew (55) a comprising a threaded lower jackscrew (5) and a threaded upper jackscrew (6) integrated or fixed to each other. The jackscrew (55) being rotatable around a primary axis of the main body (1) and stationary along said primary axis, a threaded plunger rod (8) which is integrated to the plunger (7) and which has a thread diameter (Dp) corresponding to thread diameter of the lower jackscrew (5). A button (12) is engageable with the spindle (10), 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 (10). The threaded mainly cylindrical spindle (10) has a thread diameter (Ds) corresponding to thread diameter of the upper jackscrew (6). The thread diameter (Ds) of the spindle (10) is greater than the thread diameter (Dp) of the plunger rod (8).
