Abstract: A ball screw actuator for aircraft control surfaces includes a lead screw, a motor to set the screw in rotation about its longitudinal axis and a primary body connected to a control surface and engaged on the control screw via a plurality of balls movable on the thread of the screw. A secondary body is connected to the primary body and has an auxiliary portion provided with an engagement surface facing the thread of the lead screw at a predetermined distance; the engagement surface is shaped to engage on the thread of the lead screw. The actuator also includes a device for uncoupling the secondary body from the auxiliary portion in the rotation motion about the longitudinal axis.

Abstract: A ball screw actuator for aircraft control surfaces comprises a lead screw, motor means to set the screw in rotation about its longitudinal axis and a primary body connected to a control surface and engaged on the control screw by means of a plurality of balls movable on the thread of said screw. A secondary body is connected to the primary body and has an auxiliary portion provided with an engagement surface facing the thread of the lead screw at a predetermined distance; the engagement surface is shaped to engage on the thread of said lead screw. The actuator further comprises means for uncoupling the secondary body from the auxiliary portion in the rotation motion about the longitudinal axis.