A mechanism for closing a hinged member with respect to a fixed frame, the mechanism comprising an actuator (4; 49) connectable to the hinged member for effecting closure of the hinged member and a hydraulic damper (5; 60) for damping the closing movement of the hinged member, which hydraulic damper (5; 60) comprises: - a cylinder barrel (19; 68); - a closed cylinder cavity (20; 70) formed within the cylinder barrel (19; 68); - a piston (21; 72) placed within the closed cylinder cavity (20; 70) so as to divide the closed cylinder cavity (20; 70) into a first side (20a; 70a) and a second side (20b; 70b); and - a damper shaft (22; 62) coupled to the piston (21; 72); characterised in that at least at 20°C, an outer perimeter surface of the piston (21; 72) defines a clearance between an inner perimeter surface of the cylinder barrel to allow hydraulic fluid contained in the cylinder cavity (20; 70) to flow through the clearance between the outer perimeter surface of the piston (21; 72) and the inner perimeter surface of the cylinder barrel between the first side (20a; 70a) and the second side (20b; 70b) of the closed cylinder cavity (20; 70); and in that the cylinder barrel (19; 68) is made of a first material, having a first thermal expansion coefficient and the piston (21; 72) is made of a second material having a second thermal expansion coefficient, the second thermal expansion coefficient being larger than the first thermal expansion coefficient so that the clearance decreases when the temperature of the damper (5; 60) is raised and increases when the temperature of the damper (5; 60) is lowered, the hydraulic damper comprises a rotation damper, and in that the piston comprises: - at least one helical thread for engaging a corresponding thread formed on the damper shaft; and - a rotation-preventing member, preventing rotation between the piston and the cylinder barrel so that rotational motion of the damper shaft with respect to the cylinder barrel around a longitudinal axis of the damper shaft results in a translational motion of the piston along the longitudinal axis. - a cylinder barrel (19; 68); - a closed cylinder cavity (20; 70) formed within the cylinder barrel (19; 68); - a piston (21; 72) placed within the closed cylinder cavity (20; 70) so as to divide the closed cylinder cavity (20; 70) into a first side (20a; 70a) and a second side (20b; 70b); and - a damper shaft (22; 62) coupled to the piston (21; 72); characterised in that at least at 20°C, an outer perimeter surface of the piston (21; 72) defines a clearance between an inner perimeter surface of the cylinder barrel to allow hydraulic fluid contained in the cylinder cavity (20; 70) to flow through the clearance between the outer perimeter surface of the piston (21; 72) and the inner perimeter surface of the cylinder barrel between the first side (20a; 70a) and the second side (20b; 70b) of the closed cylinder cavity (20; 70); and in that the cylinder barrel (19; 68) is made of a first material, having a first thermal expansion coefficient and the piston (21; 72) is made of a second material having a second thermal expansion coefficient, the second thermal expansion coefficient being larger than the first thermal expansion coefficient so that the clearance decreases when the temperature of the damper (5; 60) is raised and increases when the temperature of the damper (5; 60) is lowered, - at least one helical thread for engaging a corresponding thread formed on the damper shaft; and - a rotation-preventing member, preventing rotation between the piston and the cylinder barrel so that rotational motion of the damper shaft with respect to the cylinder barrel around a longitudinal axis of the damper shaft results in a translational motion of the piston along the longitudinal axis.