Nacelle for an aircraft engine with cascade-type thrust reverser and variable-geometry nozzle

1. An aircraft engine nacelle, comprising:

a fixed front frame,

a thrust reverser cowling mounted to slide with respect to said front frame between a direct-jet position and a reversed-jet position,

a variable-geometry nozzle positioned in a downstream continuation of said thrust reverser cowling,

thrust-reversal jacks interposed between said fixed front frame and said thrust-reverser cowling,

variable-geometry nozzle jacks interposed between said thrust reverser cowling and said variable-geometry nozzle,

drive shafts connected to and moved by motors mounted on said front frame,

transmission shafts extending longitudinally along said thrust reverser cowling and directly connected to said variable-geometry nozzle jacks which they activate, and

mechanical means for coupling said transmission shafts to said drive shafts, to transmit torque from said drive shafts to said transmission shafts when said cowling is in the direct-jet position, and to decouple the transmission shafts from the drive shafts when said cowling slides toward its reversed-jet position, and

means for locking rotation of said transmission shafts before decoupling of the transmission shafts from their respective drive shafts, and when the decoupling is completed.

2. The nacelle according to claim 1 , wherein said locking means are actuated under the effect of separation of the thrust reverser cowling from said fixed front frame when said thrust reverser cowling slides toward its reversed-jet position.

3. The nacelle according to claim 2 , wherein said locking means comprise, for each transmission shaft:

jaw locking means, fixedly mounted on said thrust reverser cowling,

a jaw drawer slidingly mounted and blocked in rotation in relation to the transmission shaft, said jaw drawer comprising locking jaws, able to cooperate with said locking means, and driving jaws, able to cooperate with a toothed wheel driven by each respective drive shaft, and

elastic return means for returning said jaw drawer toward said toothed wheel,

the respective dimensions of the jaw locking means, the jaw drawer, and the elastic return means being such that:

when said reverser cowling is in the direct-jet position, said driving jaws cooperate with their associated toothed wheel, and

when said reverser cowling moves away downstream of said front frame, said locking jaws engage with said locking means under the action of said elastic means before said driving jaws have escaped their associated toothed wheel.

4. The nacelle according to claim 1 , wherein the variable-geometry nozzle of said nacelle is of the type having pivoting flaps.