Mechanical device ensuring irreversibility in a limiter assembly for actuators coupled through a reversible kinematic chain

A mechanical device for ensuring an irreversibility in a limiter assembly including at least one limit switch (3) having a normal and an off-normal position, said mechanical device comprising means responsive to an initiating action coupled to move said at least one limit switch (3) to said off-normal position for the duration of the initiating action, mechanical means comprising a ribbon (15)of material which is rigidly associated with a moving element (11 ), wherein said moving element operates said at least one limit switch (3), said ribbon having two projections (16), two toothed sprockets (17) mounted to freely rotate on two individually associated shafts (12), said two projections selectively engaging teeth on individually associated ones of said sprockets, each of said shafts being partly enveloped by an individually associated spring (18) coiled in such a direction that when either projection (16) engages the teeth of the corresponding sprocket (17), and the shaft (12) individually associated therewith is allowed to rotate in only one direction, concurrently with the direction in which the spring is coiled relative to the sprocket, wherein after termination of the initiating action, said at least one limit switch is moved to said normal position.