Actuator for non linear paths, provided with an endless screw (31), driven by an electric motor (3). Said endless screw, by being screwed in a threaded cavity (23) of a cylindrical element (22), linked to a slider (24) by a flexible plate (21), drives said slider (24) and a movable element linked to it, like a glass of a door of a car, along a curved path determined by a rail (11, 12).

While driving said slider (24), said flexible plate (21) is forced to flex itself, so as to compensate differences and variations in position and orientation between said endless screw (31) and said rail (11, 12).

A thrust bearing group (4), at the end (32) of said endless screw (31), holds the force said endless screw is loaded with, while driving said slider (24) towards the end (14) of a base plate (1).

This window lifter can be realized with as low as 7 to 12 components, according to configurations, compared with 30-40 components needed for state of art cable-based window lifters.

Alternative configurations, which may fit a reduced space in a  door, and particularly a reduced admissible total length of the actuator, are based on different positions of the electrical motor. In these alternative configurations, the endless screw is hold by two thrust bearings, and two cylindrical or conical toothed wheels gear the endless screw with the shaft of the electrical motor.

Feasibility is demonstrated by past applications of endless screw window lifters, which were used in the '60 and then abandoned when glasses became curved, and by more recent flexible endless screw window lifters.

In order to avoid clearance between the endless screw (31) and the threaded element (22), a "C" shaped spring may be added to the threaded element, which, with cooperation of thermal cycles, will gradually compress the threaded element, compensating for wear.

Simulations show the feasibility of a non lubricated device, wherein the threaded element and the thrust bearing(s) are made of low friction plastics, like Nylon 66 (COF = 0,09) or Teflon (COF 0,1 or less). By choosing appropriate thread pitch, the device may be dimensioned in order to optimize speed, heating by attrition and avoid creep in the threaded element and in the thrust beraring(s).