Patent ID: 8104995

Claim:
A marine pipeline installation tensioner comprising a tensioner frame and multiple track units mounted in said frame, wherein each track unit includes an endless track, a chassis, bearing means, mounted on said chassis for supporting the endless track, and one or more track motion control members for effecting controlled motion of the track, and wherein each track unit is arranged mobile within the associated frame by a parallel linkage bar system with parallel linkage bars between the chassis of the track unit and the frame of the tensioner, wherein the parallel linkage bars are respectively connected to the chassis of a track unit near either end of said chassis, and one or more further parallel linkage bars are connected to the chassis in intermediate positions of the chassis, such that said chassis of the track unit is supported at least in both end regions thereof as well as in a central region by each of said parallel linkage bars, wherein at least three actuators are provided between each track unit chassis and the frame, and the at least three actuators are provided at spaced locations along the length of the chassis, wherein two of the at least three actuators are connected to the chassis of the track unit and are respectively near opposite ends of the chassis, and another one of the at least three actuators is connected to the chassis of the track unit in an intermediate position of the chassis, such that the at least three actuators exert a force on the chassis at least in both end regions of the chassis as well as in a central region of the chassis, and wherein control means are associated with said at least three actuators that allow to independently control the force exerted by said at least three actuators on the chassis, and thus to control a bending behaviour of the chassis and to independently set a pressure with which the tracks engage the pipeline at different regions along the length of each chassis.