There is provided a device for handling and storage of a traveling unit of an offshore crane. More precisely there is provided a device for handling and storage of at least one traveling unit of an offshore crane where the term traveling unit may include one or more of such items as a single-line hook, a sheave block hook or at least a part of a modular hook system.

Below, definitions and background art are given for equipment and operations related to the present invention.

Offshore Cranes: Offshore cranes are used to lift heavy loads, often into and out of the sea and to and from the seabed. Such cranes are generally placed at a vessel's side on a large, open main deck suitable for placing and manoeuvring large loads. Such cranes make use of a suitably large, heavy hook and may alternatively be rigged to employ a hook integrated with a sheave block to share the lifting load between lift wire parts.

Hook Handling : Hooks and hook parts are generally constrained in a stable parking or storage position when not in use. It must also be possible to disconnect the hooks from and reconnect them to the crane's lift wire for the purpose of exchanging one hook for another - even while the ship is at sea. Thus, moving a hook between positions provided for storage, connection and rigging and lifting is essential as is supporting it while rigging is done. Such work is here included in the term "hook handling".

Terminology: The following other terms and naming conventions are used herein : single-line hook: a hook designed to be attached to a single wire rope for normal lifting of crane loads. sheave block hook: a hook assembly which incorporates a sheave block above a lower hook part. The sheave block contains one or more sheaves around which the lift line is reeved in order to share the lifting load between lift wire parts. modular hook system: a common lower hook part or parts may be used in a single- line hook assembly or used together with a sheave-block upper part or parts which together form a larger sheave block hook assembly for heavier lifts. parked crane, or crane jib: a crane jib is lowered completely to its resting position within a jib rest; working hook: the hook that is attached to the crane lift wire: it may be in use or parked; stored hook: a hook that is not connected to the crane lift wire; it is placed in a supporting structure: thus a hook may be "working", "stored" or in movement between the two states; parked hook: a working hook is temporarily placed in a supporting structure, typically while the crane is parked; hook landing : when the crane lowers its empty hook into a support structure such that it is constrained for parking or storage; hook home position : the horizontal position in which the hook falls naturally when at rest, for example on deck, beneath its lift wire. This position will vary with jib angle and crane slew position; overboarding area : a free area in elevation/side view in which the crane lifts its load over the vessel's side. This area is generally bounded inward by the crane foundation/house itself, downward by the deck or deck railing or other vessel structure, outward by the crane's maximum relevant lift radius or jib-rest and upward by the crane's own jib.

General challenges: The effort and hazards inherent in handling the hooks as defined above, and the lift wire itself can be considerable given their relatively large size and weight. The crane itself is often required to lift and support items during handling operations. Such work involves manual labour by deck crew on the deck and occasionally at heights above it. It often includes the use of other winches and lifting gear as well, presenting risks of great consequence. These hazards and difficulties are increased greatly by sea-induced ship movement. Pendulum Motions: Significant dangers and difficulty arise whenever a hook is free from its restraints and subject to pendulum motions. Whenever an empty hook is landed, the only means of control prior to its capture and restraint is via the crane winch, crane jib movements and slewing of the crane's upper structure. As the crane jib-end is usually quite high, the hook is subject to considerable pendulum motions which can be very difficult to combat and which present great risk to nearby personnel, equipment and structures. The standard method for parking a hook is to lower it, via the crane, into a deck-mounted hook bucket which then prevents pendulum motions. Storage of other hooks, sheave blocks or hook parts is done in a variety of ways, but often requires moving them by lifting them with the help of the crane itself, either using the main lift wire or an alternate lift wire, which again results in the unpredictable pendulum movements of large, heavy objects.

Use of space: The storage locations of non-working hooks or hook parts must keep them reasonably safe from possible collisions with the working hook or loads. These structures tend to be quite large and can claim excessive deck space in addition to obstructing the overboarding area, especially when they contain a large, stored hook.

The purpose of the invention is to overcome or reduce at least one of the disadvantages of the prior art.

The purpose is achieved according to the invention by the features as disclosed in the description below and in the following patent claims.

There is provided a device for handling and storage of at least one traveling unit of an offshore crane where the term traveling unit may include one or more of such items as a single-line hook, a sheave block hook or at least a part of a modular hook system, wherein the device includes a first cradle that is designed to receive a traveling unit, and a second cradle that is designed to receive another traveling unit and where the first cradle and the second cradle are movable relative to each other.

The invention provides a device for onboard storage and handling such as placement, movement and exchange of hooks and/or hook parts for offshore cranes. The term "traveling unit" is here limited to include items positioned between the lift wire and the hook, the hook included, but not auxiliary lifting tools such as chain slings and the like.

The first cradle and the second cradle may be at different vertical heights. Thus, it may be possible to move a traveling unit that is positioned in one of the first or second cradles, across another traveling unit that is positioned in the other cradle. A traveling unit, when resting in one of the first or second cradles, may be horizontally movable for instance to make room for another traveling unit in the same horizontal space or in the same cradle.

The traveling unit, when resting in one of the first or second cradles, may be horizontally fixed in one axis, but horizontally movable in another axis.

The traveling unit, when resting in one of the first or second cradles, may be horizontally fixed.

At least one of the first or second cradles may have means for moving the traveling unit a limited distance in the vertical direction. Such means may be in the form of a mechanical or hydraulic jack or other suitable equipment.

At least one of the first or second cradles may extend into a space within the ship structure or a crane jib rest. The jib rest normally includes a frame work. By extending at least one of the cradles into an opening in such a structure or frame work hook storage space on deck is reduced.

At least one of the first or second cradles may be movable between the space in the ship structure or jib rest and a position outside the jib rest. Thus cradles receiving a traveling unit outside this provided space may be moved into the space.

A traveling unit that is positioned in the first cradle, and a traveling unit that is positioned in the second cradle, may have a common horizontal position .

If a modular hook system is utilized, the sheave block module may be positioned in the upper of the first or second cradles, and the hook module may be positioned in the lower of the first or second cradles for connecting or disconnecting said items.

The device according to the invention specifically address typical challenges such as:

• safely landing a hook in a parking or storage cradle on deck;

• moving hooks and hook parts from one location to another in a controlled and safe manner;

• precisely manoeuvring and positioning the hooks and hook parts in relation to each other and holding them securely in place while connecting, disconnecting and rigging;

• safely and effectively moving a heavy wire, parts and fasteners at height above deck using manual labour;

• moving and using a hook without damaging the other hook or hook parts

stored nearby; and

• storing large hooks and hook parts in such a way that does not claim excessive deck space or excessively obstruct the crane's overboarding area.

Below, an example of a preferred device is explained under reference to the enclosed drawings, where:

Fig. 1 shows an axonometric view of first cradle and a second cradle according to the invention;

Fig. 2 shows the same as in fig. 1, but with traveling units placed in the cradles;

Fig. 3 shows an orthographic end view of the first cradle;

Fig. 4 shows an orthographic side view of the first cradle;

Fig. 5 shows an orthographic end view of the first and second cradle; and

Fig. 6 shows an orthographic side view of the first and second cradle.

On the drawings, the reference number 1 denotes a first cradle that is positioned on a vessel's 2 deck 4. The first cradle 1 may be positioned outside, see fig. 1, or partly inside a space 6 in a jib rest 8 or other ship structure 9. In some cases the jib rest 8 may be a relatively small structure on top of the ship structure 9.

The first cradle 1, which in this preferred embodiment has an elongated form, has a structure 10 that here is fixed to the deck 4. The structure 10 includes a pair of horizontal rails 12 as well as a pair of flared guides 14 positioned above the rails 12. The guides 14 are designed to guide a traveling unit 16 in the form of a single line hook 18 or hook lower part 20 of a modular hook system 21, during landing on the rails 12. The traveling unit 16 is movable along the rails 12.

A space 22 is provided between and below the rails 12 for a hook 24 of the traveling unit 16 to extend into. The hook 24 is shown in figs. 3-6.

A second cradle 26, which in this preferred embodi ment is formed as an open- bottomed basket, is placed on guiding surfaces 28 that are fixed to the deck 4. The second cradle's 26 structure 30 has flared support members 32 that are designed to guide and support the traveling unit 16 in the form of a sheave block hook 34 or a sheave block upper part 36 of a modular hook system 21 during landing in the cradle. The sheave block upper part 36 of the modular hook system 21 may or may not have a hook lower part 20 connected. In figs. 5-6 a modular hook system 21 is shown that includes the sheave block upper part 36 and the hook lower part 20. A complete sheave block hook 34 lacks the modularity of the modular hook system 21.

The second cradle 26 is movable along the guiding surfaces 28 between a position outside the jib rest 8 or the ship structure 9 and a position in the space 6 inside the jib rest 8 or ship structure 9.

A traveling unit 16 positioned in the first cradle 1 is movable along a first axis 38. A traveling unit 16 positioned in the second cradle 26 is movable with the second cradle 26 along a second axis 40. The two axes 38 and 40 share a common vertical plane.

Thus, if a sheave block upper part 36 of a modular hook system 21 is positioned in the second cradle 26 and a hook lower part 20 of the modular hook system 21 is positioned in the first cradle 1, the items 36, 20 may be moved to a common position for connection.

Such items as a tugger winch, not shown, may be used for moving the traveling unit 16 in the first cradle 1 and the second cradle 26 along the guiding surfaces 28.

As indicated in figures 2-6, different traveling units 16 may be stored or parked at different positions in the first cradle 1, or in the second cradle 26, also in the space 6 of the jib rest 8 or ship structure 9.