Reclinable passenger seat

1. A reclinable passenger seat comprising:

a base configured to be connected to a floor structure;

a seat pan frame supporting a seat pan and having a front end connected to the base via a first fixed pivot;

a support arm having one end connected to the base via a second fixed pivot located aft of the first fixed pivot;

a backrest frame having an upper backrest member supporting a backrest and a lower backrest member extending downwardly from the upper backrest member, an opposed end of the support arm pivotally connected to the lower backrest member at a first location spaced from the upper backrest member, a rear end of the seat pan frame pivotally connected to the lower backrest member at a second location between the first location and the upper backrest member; and

a linear actuator having one end pivotally connected to the lower backrest member and to the rear end of the seat pan frame at the first location, and an opposed end pivotally connected to the base by a third fixed pivot located between the first and second fixed pivots;

wherein the backrest frame and seat pan frame are configured to move simultaneously between a sitting configuration and a reclined configuration through pivoting motion about the first and second fixed pivots and about the first and second locations.

2. The reclinable passenger seat as defined in claim 1 , wherein the upper and lower backrest members are interconnected by a selectively lockable pivot connection having a locked configuration where a relative pivoting motion between the upper and lower backrest members is prevented and an unlocked configuration where the relative pivoting motion between the upper and lower backrest members is allowed.

3. The reclinable passenger seat as defined in claim 1 , wherein the second fixed pivot connecting the support arm to the base is located under the backrest frame.

4. The reclinable passenger seat as defined in claim 3 , wherein the first and second locations on the lower backrest member remain forward of the second fixed pivot as the backrest frame and seat pan frame move between the sitting configuration and the reclined configuration.

5. The reclinable passenger seat as defined in claim 1 , wherein a distance between the second fixed pivot and the first location is about twice a distance between the first and second locations.

6. The reclinable passenger seat as defined in claim 1 , wherein the first and second locations on the lower backrest member remain aft of the third fixed pivot as the backrest frame and seat pan frame move between the sitting configuration and the reclined configuration.

7. The reclinable passenger seat as defined in claim 1 , wherein the upper and lower backrest members extend non-parallel to one another.

8. The reclinable passenger seat as defined in claim 7 , wherein the upper and lower backrest members extend at an angle of about 135 degrees with respect to one another.

9. A reclinable passenger seat comprising:

a base configured to be connected to a floor structure;

a seat pan frame supporting a seat pan and having a front end connected to the base via a first revolute joint;

a support arm having one end connected to the base via a second revolute joint located aft of the first revolute joint;

a backrest frame having an upper backrest member supporting a backrest and a lower backrest member extending downwardly from the upper backrest member, the upper and lower backrest members having at least a first configuration where the upper and lower backrest members have a fixed orientation with respect to one another, an opposed end of the support arm connected to the lower backrest member via a third revolute joint spaced from the upper backrest member, a rear end of the seat pan frame connected to the lower backrest member by a fourth revolute joint located between the third revolute joint and the upper backrest member; and

a linear actuator having one end connected to the fourth revolute joint connecting the seat pan frame to the lower backrest member, and an opposed end pivotally connected to the base by a fifth revolute joint located between the first and second revolute joints;

wherein the backrest frame and seat pan frame are configured to move simultaneously between a sitting configuration and a reclined configuration through pivoting motion about the first, second, third and fourth revolute joints while the upper and lower backrest members are in the first configuration.

10. The reclinable passenger seat as defined in claim 9 , wherein a distance between the second and third revolute joints is about twice a distance between the third and fourth revolute joints.

11. The reclinable passenger seat as defined in claim 9 , wherein the upper and lower backrest members are interconnected by a selectively lockable revolute joint, the first configuration being a locked configuration where a relative pivoting motion between the upper and lower backrest members is prevented, the selectively lockable revolute joint having an unlocked configuration where the relative pivoting motion between the upper and lower backrest members is allowed.

12. The reclinable passenger seat as defined in claim 9 , wherein the second revolute joint connecting the support arm to the base is located under the backrest frame.

13. The reclinable passenger seat as defined in claim 12 , wherein the third and fourth revolute joints on the lower backrest member remain forward of the second revolute joint connecting the support arm to the base as the backrest frame and seat pan frame move between the sitting configuration and the reclined configuration.

14. The reclinable passenger seat as defined in claim 9 , wherein the third and fourth revolute joints on the lower backrest member remain aft of the fifth revolute joint connecting the linear actuator to the base as the backrest frame and seat pan frame move between the sitting configuration and the reclined configuration.

15. The reclinable passenger seat as defined in claim 9 , wherein in the first configuration, the upper and lower backrest members extend non-parallel to one another.

16. The reclinable passenger seat as defined in claim 15 , wherein in the first configuration, the upper and lower backrest members extend at an angle of about 135 degrees with respect to one another.