Actuation mechanism

An actuation mechanism for a thrust vectoring variable geometry nozzle of a gas turbine engine, the actuation mechanism comprising:

• a first ring;
• a second ring;
• a third ring;
• a fourth ring;
• first actuating means;
• and
• second actuating means;
• wherein according to at least one operational status of the first and second actuating means the four rings are arranged concentrically and about a longitudinal axis,
• wherein the first actuating means are configured to exert a pushing or pulling force in the direction of the longitudinal axis on at least two diametrically opposed actuation points of the third ring;
• and
• wherein the second actuating means are configured to exert a pushing or pulling force in the direction of the longitudinal axis on at least two diametrically opposed actuation points of the fourth ring;
• wherein in said operational status of the first and second actuating means:
• a first plane is defined by the longitudinal axis and the line connecting the actuation points of the third ring,
• a second plane is defined by the longitudinal axis and the line connecting the actuation points of the fourth ring,
• the first plane and the second plane are perpendicular;
• and wherein:
• the first ring has the smallest diameter among the four rings, and is configured to be coupled to a distal fixed portion of the nozzle by means of an axial sliding joint arranged in the direction of the longitudinal axis, such that in an operating mode of the actuation mechanism the first ring is configured to move axially with respect to said distal fixed portion of the nozzle;
• the second ring has a larger diameter than the first ring and is connected to the first ring by means of at least one first cylindrical joint arranged on the first plane, wherein said first cylindrical joint is configured to allow relative rotation between the first ring and the second ring around a first rotation axis perpendicular to the longitudinal axis;
• the third ring has a larger diameter than the second ring;
• the fourth ring has a larger diameter than the second ring and is connected to the third ring by means of at least one axial sliding joint arranged in the direction of the longitudinal axis, such that the fourth ring and the third ring are configured to move axially relative to each other;
• the fourth ring being further connected to the second ring by means of at least one second cylindrical joint arranged on the second plane, wherein said second cylindrical joint is configured to allow relative rotation between the fourth ring and the second ring around a second rotation axis perpendicular to the longitudinal axis.