Linear actuator for gates, doors and the like

A linear actuator for operation of gates, doors or barriers provided with at least one closing wing (5) swinging around a substantially vertical oscillation axis (6), the linear actuator comprising an articulated actuator arm (1) designed to be rotatably mounted onto a fixed support (2) to swing around a traversing axis (15) substantially parallel to the oscillation axis (6) of the wing (5) and near the oscillation axis (6), with the actuator arm (1) comprising an irreversible handling pair consisting of a screw (7) and a respective nutscrew (8) of which the screw (7) extends in the longitudinal direction of the actuator arm (1) and is operated at a rear end turned towards the actuator arm traversing axis (15) by an electric motor (11) and by a reduction gear (12) assembled in the actuator arm (1) while the nutscrew (8) slides along the actuator arm (1) and is designed to be rotatably connected to the wing (5) or to a part (4) fastened to the wing (5), so as to rotate around an articulation axis (21) substantially parallel to the oscillation axis (6) of the wing (5), wherein the actuator arm (1) comprises, at an end designed to be mounted onto the fixed support (2), a first joint (14) allowing, in addition to oscillation of the actuator arm (1) around the traversing axis (15), an angular rotation in a vertical plane of the actuator arm upward around an inclination axis (16) substantially horizontal and transversal to the actuator, and the rotatable connection between the nutscrew (8) and the wing (5) comprises a second joint allowing disengagement of the nutscrew from the wing by means of an upward angular shift of the actuator arm (1) around the inclination axis (16) thereof.