Patent ID: 8146858

Claim:
A no-back device for an actuating device for a mobile actuating element with a screw type actuating shaft, the no-back device comprising: first ( 3 , 5 , 7 , 9 , 11 , 15 , 19 ) and second ( 4 , 6 , 8 , 10 , 12 , 16 , 18 ) brakes, each having a ratchet wheel ( 5 , 6 ), the ratchet wheels mounted in opposition to each other with the first brake designed to resist an unwanted movement of the shaft in a first direction, and the second brake designed to resist an unwanted movement of the shaft in an opposite direction, a processor associated with sensors and designed to determine the state of rotation of each wheel, wherein the state of rotation indicates whether the wheel is stationary or driven in rotation, and indicating means to supply an indication relating to the operational state of the no-back device, the indicating means including means for comparing the state of rotation of each of the wheels as determined by the processor, and alert means for supplying an indication of failure when the compared rotation states are identical.