Patent ID: 8253288

Claim:
An electric actuator for driving a home-automation screen mounted to move between an open position and a closed position, said actuator being provided with a spring brake, said brake comprising: a helical spring, each end of which forms a respective tab extending radially or axially relative to a central axis of the spring; a friction part having a substantially cylindrical friction surface against which at least one turn of the helical spring bears radially; an inlet part driven by an electric motor of the actuator, and suitable for coming into contact with at least one tab of the spring, in such a manner as to drive the spring in rotation about a central axis of the brake, in a direction making it possible to reduce the contact force between the helical spring and the friction surface; and an outlet part connected to the screen and suitable for coming into contact with at least one tab of the spring in such a manner as to drive the spring in rotation about the central axis of the brake, in a direction making it possible to increase the contact force between the helical spring and the friction surface; in which actuator, while the screen is being lowered, the inlet part drives the spring in rotation with the contact force being decreased to the extent that the outlet part is released in rotation, without direct contact between the inlet part and the outlet part; wherein the inlet part has at least two contact surfaces adapted to transmit a drive torque for raising the screen, by direct contact, to at least two corresponding contact surfaces of the outlet part.