This document describes a mobile heave compensator (100) provided with an attachment device (15) for suspending the compensator from a load bearing device (102) and an attachment device (14) for carrying a payload (101). The compensator comprises a passive heave compensation part and possibly an active heave compensation part, and being associated with a sensor arrangement producing input signals for a control unit and a power source (71). The compensator (100) incorporates a gas pump and/or motor device (70), affecting the passive heave compensating part, producing output signal(s) to the gas pump device (70), based on input signals received from the sensor arrangement, to enable flow of gas towards a volume with a higher pressure.

This document describes a mobile heave compensator (100) provided with an attachment device (15) for suspending the compensator from a load bearing device (102) and an attachment device (14) for carrying a payload (101). The compensator comprises a passive heave compensation part and possibly an active heave compensation part, and being associated with a sensor arrangement producing input signals for a control unit and a power source (71). The compensator (100) incorporates a gas pump and/or motor device (70), affecting the passive heave compensating part, producing output signal(s) to the gas pump device (70), based on input signals received from the sensor arrangement, to enable flow of gas towards a volume with a higher pressure.

A vertically-adjustable gantry assembly installation for removal or placement of a train bridge-span of the type which spans and supported by two piers, comprises a gantry assembly positioned on load-bearing first ground-support locations, the gantry assembly comprising a gantry and a ground-engaging vertical support and lift system, the vertical support and lift system adapted for supporting a combined weight of the gantry and bridge span in at least one operational vertical position above respective bridge span support-surfaces of the piers including a position corresponding to a disembarking plane in which the leg portions are extended from a viewed portion to an extent as least sufficient for the gantry assembly to self-liftoff the pre-installation conveyance system onto the first ground-support locations to effect the gantry assembly installation.

A vertically-adjustable gantry assembly installation for removal or placement of a train bridge-span of the type which spans and supported by two piers, comprises a gantry assembly positioned on load-bearing first ground-support locations, the gantry assembly comprising a gantry and a ground-engaging vertical support and lift system, the vertical support and lift system adapted for supporting a combined weight of the gantry and bridge span in at least one operational vertical position above respective bridge span support-surfaces of the piers including a position corresponding to a disembarking plane in which the leg portions are extended from a viewed portion to an extent as least sufficient for the gantry assembly to self-liftoff the pre-installation conveyance system onto the first ground-support locations to effect the gantry assembly installation.

A wire rope device having adjustable length between a first end and a second end thereof. The wire rope device comprises a first wire rope extending from the first end and a second wire rope extending from the second end. A length adjusting structure is disposed between the first end and the second end. The length adjusting structure has the first wire rope and the second wire rope connected thereto. A support structure is disposed between the first end and the second end. The support structure has the length adjusting structure rotatable movable mounted thereto. A first guiding structure and a second guiding structure are disposed in the support structure for guiding the first wire rope and the second wire rope, respectively, such that when in operation a portion of the first wire rope extending from the first guiding element and a portion of the second wire rope extending from the second guiding element are disposed substantially along a same straight line. A drive mechanism is mounted to the support structure and connected to the length adjusting structure for adjusting the length of the wire rope device by rotatably moving the length adjusting structure.

An assembly includes a hoist or a winch, a cable, and a fleet angle sensor. The fleet angle sensor includes a frame disposed around an opening and the cable extends through the opening. A first photodetector with multiple light-receiving zones is mounted on the frame. A first light source is mounted on the frame opposite the first photodetector. A shield device is under the frame and includes a shield frame and a cover. The shield frame is around the cable and the cover extends from the shield frame toward the cable, with the cable extending through the cover.

An assembly includes a hoist or a winch, a cable, and a fleet angle sensor. The fleet angle sensor includes a frame disposed around an opening and the cable extends through the opening. A first photodetector with multiple light-receiving zones is mounted on the frame. A first light source is mounted on the frame opposite the first photodetector. A shield device is under the frame and includes a shield frame and a cover. The shield frame is around the cable and the cover extends from the shield frame toward the cable, with the cable extending through the cover.

A method and related device for reducing resonant vibrations and dynamic loads of cranes, where vertical motion of a pay load is controlled by a boom winch and a hoist winch. In an embodiment, the method includes determining resonance frequencies of the crane boom and pay load from inertia data of the boom and stiffness on at least the boom and hoist ropes, the resonance frequencies including a first frequency and a lower second frequency. In addition, the method includes automatically modifying the motion of the boom winch or the hoist winch to induce a damping inducing winch motion in the boom or hoist winch, by tuning a proportional integral (PI)-type boom winch speed controller or a PI-type hoist winch speed controller. The boom winch speed controller is tuned to absorb energy at the second frequency, the hoist winch speed controller is tuned to absorb energy at the first frequency.

A method and related device for reducing resonant vibrations and dynamic loads of cranes, where vertical motion of a pay load is controlled by a boom winch and a hoist winch. In an embodiment, the method includes determining resonance frequencies of the crane boom and pay load from inertia data of the boom and stiffness on at least the boom and hoist ropes, the resonance frequencies including a first frequency and a lower second frequency. In addition, the method includes automatically modifying the motion of the boom winch or the hoist winch to induce a damping inducing winch motion in the boom or hoist winch, by tuning a proportional integral (PI)-type boom winch speed controller or a PI-type hoist winch speed controller. The boom winch speed controller is tuned to absorb energy at the second frequency, the hoist winch speed controller is tuned to absorb energy at the first frequency.

A method for damping rotational oscillations of a load-handling element of a lifting device is created, wherein at least one controller parameter is determined by a rotational oscillation model of the load-handling element as a function of the lifting height (l.sub.H) and wherein, to damp the rotational oscillation of the load-handling element at any lifting height (l.sub.H), the at least one controller parameter is adapted to the lifting height (l.sub.H).