Patent ID: 7269871

Claim:
A seal for aircraft boarding stairs or for an aircraft boarding bridge, said seal comprising a bellows ( 5 ) that spans a gangway bottom plate ( 10 ), said bellows comprising a flexible frame ( 3 ) at its one open end and having at its other end a gantry frame ( 2 ) intended to be fastened to the aircraft boarding stairs or to the aircraft boarding bridge, the flexible frame ( 3 ) resting against the outer skin of the aircraft when the bellows is deployed and an actuation device for actuating the bellows being provided for extending and retracting the bellows, said actuation device comprising a rotatable shaft equipped with a drive, said rotatable shaft ( 40 ) permitting to wind and unwind a traction means connected to the flexible frame, wherein the actuation device ( 20 ) comprises two articulated arms ( 30 ) arranged in a spaced-apart relationship, each articulated arm ( 30 ) comprising an upper arm member ( 31 ) and a lower arm member ( 35 ) coupled to said upper arm member by a hinge, said upper arm member ( 31 ) of the articulated arm ( 30 ) being hinged to the gantry frame ( 2 ) in the roof region of the bellows ( 5 ) and the lower arm member ( 35 ) being hinged to the flexible frame ( 3 ), extension means ( 51 , 55 ) being provided for extending the bellows ( 5 ) including a first piston and cylinder unit ( 51 ) that serves to extend the lower arm member ( 35 ) relative to the upper arm member ( 31 ), and the first piston and cylinder unit ( 51 ) is hinged at its one end to the upper arm member ( 31 ) and at its other end to the lower arm member ( 35 ).