System for changing the pitch of the contra-rotating propellers of a turboshaft engine

A system for changing pitch of a first propeller and of a second propeller of a turbo-engine including an unducted fan for aircraft, the first and second propellers being coaxial and contra-rotating propellers, the system being controlled by a linear actuator which is arranged along an axis of the first and second propellers and which is connected in rotation with the first propeller, the system comprising:

• a first connecting mechanism establishing a connection between a rod of the linear actuator and the second propeller to change orientation of blades of the second propeller, said first connecting mechanism comprising an intermediate connecting bearing between the first and second propellers which has an inner race and an outer race and which is configured to transmit movement in translation of the rod of the linear actuator and break the connection in rotation of the rod of the linear actuator to the second propeller such that the orientation of the blades of the second propeller can be changed;
• and
• a second connecting mechanism associated with blades of the first propeller to change orientation of the blades of the first propeller;
• wherein the first connecting mechanism comprises:
• between the linear actuator and the intermediate connecting bearing, a first connecting means comprising at least a first connecting rod articulated to the rod of the linear actuator and to one of the inner and outer races of the intermediate connecting bearing, and
• between the intermediate connecting bearing and the blades of the second propeller, a second connecting means comprising at least one second connecting rod articulated to the other of the inner and outer races of the intermediate connecting bearing and to first rotating radial shafts respectively secured in rotation with roots of the blades of the second propeller to drive in rotation the first rotating radial shafts and the blades associated with the first rotating radial shafts as a consequence of movement in translation of the first connecting mechanism via the rod of the linear actuator.