Compact jib crane

Abstract

The present invention relates to a crane for use on a vessel, preferably a jack-up vessel, wherein the crane is provided with a boom and a boom cradle, the boom cradle supporting the boom at a support end and being fixed to the lifting end of the boom of the crane. According to the invention, the boom is pivotable about a horizontal boom pivot axis between a boom-raised position and a boom-stowed position.

Description

Technical Field

[0001] The present invention relates to a crane for use on a vessel, preferably a jack-up vessel, wherein the crane comprises a boom, a jib and a gantry. The crane, when located on the vessel, can be used for offshore installations, for example for lifting components of an offshore wind turbine, for example during installation or maintenance of the wind turbine. Background Art

[0002] NL2015896 B1 discloses a mast crane for use on ships, comprising a boom, a pivotable jib, and a pivotally supported jib lever arm. The lever arm is configured to support a jib tensioning member, which provides leverage for pivoting the jib. Both the jib and the jib lever arm are pivotally connected to the boom. The jib tensioning member extends between the jib and the crane mast and allows the jib to pivot. Summary of the Invention

[0003] The present invention aims to provide an alternative crane for use on board ships. In addition, the present invention aims to improve existing cranes by providing a more compact crane. In addition, the present invention aims to provide a compact crane with a relatively large reach.

[0004] Therefore, the present invention provides a crane according to claim 1 .

[0005] According to the present invention, a crane for use on a vessel (preferably a jack-up vessel) comprises:

[0006] - a base to be mounted to the vessel or to be formed integrally with the vessel;

[0007] - a crane housing, the crane housing being rotatably supported by the base so as to allow the crane housing to rotate relative to the base about a vertical rotation axis;

[0008] a boom having a pivot end, a midsection, and a hoist end opposite the boom's pivot end, wherein the boom is supported by the crane housing such that the boom can rotate about the vertical rotation axis, and wherein the boom's pivot end is pivotally connected to the crane housing such that the boom can pivot up and down about a horizontal boom pivot axis;

[0009] a boom luffing assembly comprising a boom luffing cable and a boom luffing winch, wherein the boom luffing cable extends from the boom luffing winch to a hoisting end of the boom to pivot the boom about the pivot axis;

[0010] a main hoisting assembly comprising a main hoisting winch, a main hoisting cable and a main load suspension device, wherein the main hoisting cable extends from the main hoisting winch via at least one sheave located at a main hoisting point to the main load suspension device;

[0011] a jib hanger having a support end, a midsection, and a luffing end opposite the support end of the jib hanger, wherein the jib hanger is secured to the hoist end of the boom such that the support end and the luffing end of the jib hanger are located at opposite sides of the boom, preferably the support end and the luffing end of the jib hanger are each positioned away from the boom;

[0012] - a boom having a pivot end, a midsection, and a lifting end opposite the pivot end of the boom, wherein the pivot end of the boom is pivotally connected to the support end of the boom hanger so that the boom can pivot about a horizontal boom pivot axis between a boom raised position and a boom stowed position;

[0013] a secondary lifting assembly comprising a secondary lifting winch, a secondary lifting cable and a secondary load suspension device, wherein the secondary lifting cable extends from the secondary lifting winch to the secondary load suspension device via at least one sheave located at a secondary lifting point, preferably at the lifting end of the boom; and

[0014] - a jib luffing assembly comprising a jib luffing cable and a jib luffing winch, wherein the jib luffing cable extends from the luffing winch to the hoisting end of the jib for pivoting the jib about the jib pivot axis between the jib raised position and the jib stowed position.

[0015] The crane according to the present invention has a hanger structure formed by a jib hanger, a jib, and jib luffing cables. The jib allows for a shorter boom without reducing the crane's reach, thus making the crane lighter and more compact. According to the present invention, the jib hanger is not pivotally mounted to the boom, but is instead fixed to the boom's hoisting end and rigid relative to the boom. Thus, the present invention provides an alternative crane.

[0016] The advantage of a rigid connection between the boom and the jib hanger is that no additional structure, such as cables, rods, or chains extending from the jib hanger to, for example, the crane housing, is required to support and / or pivot the jib hanger. The absence of such structures makes the crane more compact. Furthermore, the connection between the jib hanger and the boom is more secure, providing greater stability during lifting and transport.

[0017] Furthermore, the boom hanger being fixed to the top end of the boom allows the boom to be folded towards the boom hanger (more particularly towards the boom). Thus, providing the boom with a fixed boom hanger allows a boom storage position in which the boom is located at the top end of the boom and pointing in an upward direction.

[0018] Thus, when the jib according to the invention is to be pivoted to the jib storage position, the jib luffing cables are veered inwards and the jib, more particularly the hoist end of the jib, is pivoted away from the hoist side of the boom. Thus, when the crane is in the crane storage position, the boom preferably extends in a substantially horizontal direction and the jib points upwards.

[0019] This is in contrast to prior art cranes, where the boom is typically lowered to the stowed position, i.e., the luffing cables are veered outwards so that the hoist end of the boom is pivoted towards the hoist side of the boom. Thus, when the crane is in the stowed crane position, the boom is extended in a substantially horizontal direction and the boom points downwards towards the deck of the vessel.

[0020] Thus, the present invention provides a crane having a compact storage configuration.

[0021] Preferably, when the jib is in the jib storage position, the jib is substantially vertical relative to the boom. In such embodiments, the crane allows a storage position in which the boom is substantially horizontal without the jib extending or significantly extending the length of the boom in the horizontal direction.

[0022] Furthermore, since the boom is pivoted towards the boom when in the boom storage position, the extension of the boom relative to the boom, i.e. in the vertical direction, is limited compared to prior art cranes in which the boom is pivoted away from the boom in the storage position. This is particularly the case when the boom hanger is secured to the boom at the mid-section of the boom hanger or even at the luffing end of the boom hanger.

[0023] Thus, the present invention provides a crane having a compact storage configuration.

[0024] The crane according to the present invention is suitable for use on a vessel, preferably a jack-up vessel. A vessel can include one or more cranes according to the present invention. The vessel can be used for offshore lifting operations, such as lifting wind turbines, oil rig components, or other loads.

[0025] The crane includes a fixed foundation that is mounted to or integrally formed with a vessel. For example, the fixed foundation is mounted to the deck of the vessel or, in the case of a jack-up vessel, is preferably mounted around the jack-up vessel's legs, such as the front legs. The fixed foundation supports the weight of the crane and the load carried by the crane.

[0026] The crane further includes a crane housing that is rotatably supported by the fixed base. This allows the crane housing to rotate relative to the base about a vertical rotation axis. For example, when the fixed base is positioned around the legs of a jack-up vessel, the crane housing can rotate about the legs, with the vertical rotation axis located near the center of the legs.

[0027] The crane further comprises a boom having a pivot end, a midsection and a lifting end opposite the pivot end. The boom is supported by the crane housing such that the boom can rotate about a vertical rotation axis. In addition, the boom is pivotally connected to the crane housing such that the boom can pivot about a horizontal pivot axis. The boom can thus be lowered into a boom storage position and can be raised into a boom lifting position, wherein the boom lifting position can include different lifting positions, i.e., can include several lifting positions in which the boom is oriented at different angles relative to the horizontal position, i.e., the deck of the vessel. For example, the boom can extend at an angle of 40 degrees relative to the horizontal position in a first lifting position and at an angle of 60 degrees relative to the horizontal position in a second lifting position.

[0028] The boom may be a lattice boom having a lattice structure that provides stability and rigidity to the boom.

[0029] The boom may further be a twin boom having a first midsection with a first pivot end and a second midsection with a second pivot end. The first pivot end and the second end are both pivotably connected to the crane housing such that the twin boom can pivot about a horizontal pivot axis.

[0030] According to the present invention, a jib hanger is secured to the hoist end of the boom such that the jib hanger cannot move relative to the boom. For example, the jib hanger is welded or bolted to the hoist end of the boom. The jib hanger has a support end, a midsection, and a luffing end opposite the support end of the jib hanger. The jib hanger is preferably secured to the hoist end of the boom such that the support end and the luffing end are located on opposite sides of the boom.

[0031] The jib hanger is secured to the boom such that the jib hanger extends at an angle relative to the boom. The jib hanger thus has a longitudinal axis extending between the support end and the pitch end, the longitudinal axis being perpendicular to the boom pivot axis and extending at an angle to the boom. In an embodiment, the angle enclosed by the longitudinal axis of the jib and the longitudinal axis of the boom is in the range of 80-140 degrees, preferably in the range of 90-130 degrees. In an embodiment, the jib hanger is mounted substantially perpendicular to the boom, i.e. at an angle of 90 degrees.

[0032] The jib hanger can be secured to the boom at the midsection of the jib hanger. In another embodiment, the jib hanger can be secured at or near the support end of the jib hanger. In yet another embodiment, the jib hanger can be secured at or near the pitch end of the jib hanger.

[0033] The cantilever hanger may include a lattice structure to provide stability and rigidity to the cantilever hanger.

[0034] In an embodiment, the support end and the pitch end of the cantilever hanger are each positioned away from the boom. Thus, in such an embodiment, opposite ends of the cantilever hanger are positioned away from the boom and on opposite sides of the boom. The pitch end is located on the top side of the boom, also referred to as the pitch side of the boom, and the support end of the hanger is located on the underside of the boom, also referred to as the hoist side of the boom.

[0035] The boom is pivoted about a pivot axis by a luffing assembly. The luffing assembly includes a luffing cable and a luffing winch. The luffing cable extends from the luffing winch toward the boom (e.g., toward the hoisting end of the boom) or toward the jib hanger (e.g., toward the luffing end of the jib hanger). The luffing winch can be located on the crane housing, on a fixed base, or in any other suitable location.

[0036] The crane according to the present invention further includes a main hoist assembly comprising a main hoist winch, a main hoist cable, and a main load suspension device. The main hoist cable extends from the main hoist winch via at least one sheave located at a main hoist point to the main load suspension device. The main hoist point can be located at or near the hoisting end of the boom or at or near the supporting end of the jib hanger. The load suspension device is used to suspend the load from the crane. For example, the load suspension device can include a hook.

[0037] The crane further includes a jib pivotally connected to a support end of the jib cradle such that the jib is pivotable about a horizontal jib pivot axis between a jib-raised position and a jib-stowed position. The jib includes a pivot end and a hoist end, the pivot end being connected to the jib cradle, the hoist end being positioned opposite the pivot end of the jib. The jib can be positioned in the jib-raised position when the jib is near or at a hoisting position, and can be positioned in the jib-stowed position when the vessel is moved between hoisting positions.

[0038] When the crane according to the present invention is in the crane stowed position, the boom of the crane is in the boom stowed position and the jib of the crane is in the jib stowed position. When the crane is in the crane raised position, at least the boom is in the jib raised position. Preferably, when the crane is in the crane raised position, the boom is in the jib raised position and the jib is in the jib raised position.

[0039] The raised position of the boom can include several raised positions in which the boom is oriented at different angles relative to the boom hanger structure. For example, the boom can extend at a 45-degree angle relative to the boom hanger in a first raised position and at a 70-degree angle relative to the boom hanger in a second raised position.

[0040] The jib may include a lattice structure to provide stability and rigidity to the jib. Providing a crane with a pivotable jib enhances the reach of the crane. In the raised position of the jib, the jib provides a reach that exceeds the boom length.

[0041] A secondary hoist assembly is provided, comprising a secondary hoist winch, a secondary hoist cable, and a secondary load suspension device. The secondary hoist cable extends from the secondary hoist winch to the secondary load suspension device via at least one sheave located at a secondary hoist point. The secondary hoist point is preferably located near the hoisting end of the boom, allowing full utilization of the entire length of the combined boom and jib. This increases the range of the crane, and in particular the range of the secondary hoist assembly.

[0042] The boom is pivoted about the boom pivot axis by a luffing assembly. The boom luffing assembly includes a boom luffing cable and a boom luffing winch. The boom luffing cable extends from the luffing winch to the hoisting end of the boom to pivot the boom about the boom pivot axis.

[0043] Preferably, the luffing cable extends between the jib and the luffing winch via the luffing end of the jib hanger, or the luffing winch is mounted on the jib hanger at the luffing end of the jib hanger.

[0044] The boom luffing cable extends between the boom and the luffing end of the boom hanger to pivot the boom between the boom raised position and the boom stowed position. Preferably, the boom luffing cable extends from the raised end of the boom to enable the boom to pivot effectively.

[0045] The crane according to the present invention has a hanger structure formed by a jib hanger, a boom, and jib luffing cables. The jib hanger allows the boom to be shorter without reducing the crane's reach, thus making the crane lighter and more compact. According to the present invention, the jib hanger is fixed to the hoisting end of the boom and is rigid relative to the boom. The advantage of the rigid connection between the boom and the jib hanger is that no additional structure, such as cables, rods, or chains extending from the jib hanger to, for example, the crane housing, is required to support and / or pivot the jib hanger. The absence of such structures makes the crane more compact. In addition, the connection between the jib hanger and the boom is more secure, providing greater stability during lifting and transportation.

[0046] The boom hanger, which is fixed to the top end of the boom, allows the boom to be folded toward the boom hanger (more specifically, toward the boom). Thus, providing the boom with a fixed boom hanger allows a boom storage position in which the boom is located at the top end of the boom and is substantially vertical relative to the boom. Thus, the present invention provides a crane having a compact storage configuration.

[0047] Thus, when the jib according to the present invention is to be pivoted to the jib stowed position, the jib luffing cables are unwound inwards and the jib, more specifically the hoist end of the jib, is pivoted towards the jib cradle and away from the hoist side of the boom. Thus, when the crane is in the crane stowed position, the boom is extended in a substantially horizontal direction and the jib points upwards away from the deck of the vessel.

[0048] This is in contrast to prior art cranes, in which the boom is typically lowered to the stowed position, i.e. the luffing cables are unwound so that the hoist end of the boom pivots towards the hoist side of the boom. Thus, when the crane is in the stowed crane position, the boom extends in a substantially horizontal direction and the boom points downwards towards the deck of the vessel.

[0049] In an embodiment, the jib hanger according to the invention is located at the hoisting end of the boom, where it is fixed and extends from the boom in two opposite directions. Thus, the crane according to the invention effectively utilizes the position of the jib hanger.

[0050] By extending the jib on opposite sides of the boom so that both the support end and the luffing end of the jib are spaced apart from the boom, the reach of the jib jib relative to the boom is reduced. A smaller extension of the jib jib is advantageous because a larger extension of the jib jib would make the crane less stable and less compact. Additionally, by supporting the jib at the support end of the jib jib spaced apart from the boom, the reach of the jib, and therefore the crane, is extended.

[0051] The crane of the present invention comprises a main hoist assembly, whose hoisting cables are supported at the top of the boom, and a secondary hoist assembly, whose hoisting cables are supported at the top of the jib. The main and secondary hoist assemblies can be adapted to lift different loads. For example, heavier loads can be lifted by the main hoist assembly, while lighter loads can be lifted by the secondary hoist assembly. This allows lighter loads to be lifted to a higher altitude. This is advantageous in offshore wind turbine hoisting, as wind turbine blades or wicks must typically be lifted to a higher altitude than heavier nacelles, including components such as the transmission or generator.

[0052] In an embodiment, when the jib is in the jib storage position, the jib is substantially perpendicular to the boom. This allows for a compact crane storage position in which the boom is in a substantially horizontal position, i.e., extends in a substantially horizontal direction. It is understood that large cranes, i.e., cranes with long booms, such as those used for wind turbine installation, typically have a crane storage position in which the boom is lowered to a substantially horizontal position, in which the boom extends in the longitudinal direction of the vessel. Therefore, according to the present invention, positioning the jib in the jib storage position (in which the jib extends substantially perpendicular to the boom) allows for a crane storage position in which the length of the crane, i.e., its length in the horizontal direction, is substantially not extended by the jib. Positioning the jib in the jib storage position is achieved by securing the jib hanger to the boom.

[0053] In another embodiment, when the boom is in the boom storage position, the boom is positioned substantially adjacent to and parallel to the boom hanger. In such an embodiment, the boom hanger preferably extends in a direction perpendicular to the boom. Positioning the boom parallel to and adjacent to the boom hanger provides an additional compact configuration.

[0054] In further embodiments, the boom is substantially perpendicular to the boom when the boom is in the boom storage position.

[0055] In the boom storage position, the boom is aligned with the boom hanger by pivoting the boom about a horizontal pivot axis. The secondary load suspension device can be secured when the boom is in the boom storage position. For example, the secondary load suspension device can be secured to the end of the boom by a cable or chain when the boom is in the boom storage position.

[0056] When the vessel is moved between hoisting positions, the jib is fixed in the jib storage position. On board a vessel, space is a limited commodity, so efforts should be made to reduce the size of the crane on board, particularly when the vessel is moved between hoisting positions. Having the jib adjacent to and parallel to the jib hanger reduces the overall size of the jib and hanger structure. Furthermore, the hanger structure, including the jib hanger, the jib luffing cables, and the jib in the jib storage position, occupies minimal space. When the jib hanger is fixed perpendicular to the hoisting end of the boom, this allows the hanger structure to be smaller when projected onto the vessel's deck, resulting in a smaller footprint on the vessel's deck. Overall, the crane's jib, combined with the compact storage space, results in a greater reach for the crane.

[0057] In an embodiment, a jib luffing winch is mounted on the jib hanger, preferably at the luffing end of the jib hanger, to pivot the jib between a jib raised position and a jib stowed position. This allows for a short luffing cable and, therefore, a compact jib luffing assembly. In an alternative embodiment, the luffing winch is located on the boom of the crane.

[0058] In an embodiment, the boom hanger is provided with a boom stop, and wherein when the boom is in the boom storage position, the boom is pulled against the boom stop by the boom luffing assembly to secure the boom in the boom storage position. In such an embodiment, the boom can be pulled against the boom hanger, more specifically against the boom stop provided on the boom hanger, and thus can be stored near the top end of the boom, more specifically the hoist end of the boom. In an embodiment, the boom stop extends relative to the boom to position the boom parallel to the hanger when the boom is in the boom storage position, or to prevent the boom from tilting toward the boom hanger when the boom is in the boom storage position.

[0059] Thus, the cantilever is configured to engage the cantilever stop when the cantilever is in the cantilever storage position. In an embodiment, the cantilever is provided with a cantilever stop engagement structure for cooperating with the cantilever stop, the cantilever stop engagement structure being mounted on the cantilever and extending away from the cantilever such that the cantilever stop engagement structure positions the cantilever relative to the cantilever stop when the cantilever is in the cantilever storage position. In such an embodiment, the cantilever stop and the cantilever stop engagement structure are configured to cooperate with the cantilever and position the cantilever relative to the cantilever hanger when in the cantilever storage position. Thus, the cantilever stop engagement structure can be used to position the cantilever parallel to the hanger when the cantilever is in the cantilever storage position, or to prevent the cantilever from tilting toward the cantilever hanger when the cantilever is in the cantilever storage position.

[0060] In an embodiment, the primary lifting point is located at the support end of the jib hanger, which is positioned away from the top end of the boom. Thus, the primary load suspension device is located directly below the support end of the jib hanger and spaced apart from the top end of the boom. This creates a distance between the primary load suspension device and the boom, allowing a wider range of loads of varying sizes to be lifted, particularly when the jib hanger is secured to the boom at its mid-section or even at its pitch end. Specifically, this embodiment allows for the lifting of larger loads even when the boom is oriented relatively vertically. This reduces the likelihood of the load striking the boom during the lift. The jib hanger is able to support the load during the lift because it is secured to the lifting end of the boom. Advantageously, the jib hanger is secured to the lifting end of the boom via the mid-section of the jib hanger.

[0061] In an embodiment, the crane includes a locking mechanism for locking the boom in the boom storage position. The locking mechanism may include a clamp for gripping the boom, the clamp being connected to the boom hanger. When the boom is in the boom storage position, the clamp grips the boom so that the boom cannot move, thereby creating a safer condition when the boom is in the boom storage position. Preferably, the locking mechanism is configured to secure the boom to the boom hanger, preferably to a boom stop mounted on the boom hanger.

[0062] In embodiments, the boom of the crane can be placed in a boom storage position during transport between hoisting locations. In the boom storage position, the boom is substantially horizontal relative to the vessel's deck. In this position, the boom cradle is preferably substantially vertical, and thus the boom cradle has a smaller footprint on the vessel's deck. Advantageously, when the boom is in the boom storage position, the boom is adjacent to and parallel to the boom cradle, resulting in a smaller footprint on the vessel's deck when the boom is in the boom storage position. Thus, these embodiments further enable a compact storage configuration for the crane.

[0063] In an embodiment, the cantilever includes an A-shaped frame, the A-shaped frame includes a left cantilever section and a right cantilever section, each cantilever section includes a pivot end, a middle section and a lifting end, and wherein the two cantilever sections are connected at the lifting end and are spaced apart relative to each other at the pivot end.

[0064] In such embodiments, the boom thus includes a left boom pivot end connected to the left boom midsection and a right boom pivot end connected to the right boom midsection, both of which are pivotally connected to the support end of the boom hanger. In embodiments, the left boom midsection and the right boom midsection are connected to each other at the lifting end of the boom. A boom including an A-frame, or a left boom pivot end connected to the left boom midsection and a right boom pivot end connected to the right boom midsection, provides greater stability.

[0065] It is contemplated that in such embodiments, the jib hanger may include left and right jib hanger sections (supporting left and right boom sections, respectively) and / or may be located between the two boom pivot ends.

[0066] The invention further relates to a vessel comprising a crane according to one or more of claims 1 to 8.

[0067] The invention further relates to a vessel, preferably a jack-up vessel, comprising a crane, said vessel comprising:

[0068] -deck;

[0069] - a base mounted to the vessel or formed integrally with the vessel;

[0070] - a crane housing, the crane housing being rotatably supported by the base so as to allow the crane housing to rotate relative to the base about a vertical rotation axis;

[0071] a boom having a pivot end, a midsection, and a hoist end opposite the boom's pivot end, wherein the boom is supported by the crane housing such that the boom can rotate about the vertical rotation axis, and wherein the boom's pivot end is pivotally connected to the crane housing such that the boom can pivot up and down about a horizontal boom pivot axis;

[0072] a boom luffing assembly comprising a boom luffing cable and a boom luffing winch, wherein the boom luffing cable extends from the boom luffing winch to a hoisting end of the boom to pivot the boom about the pivot axis;

[0073] a main hoisting assembly comprising a main hoisting winch, a main hoisting cable and a main load suspension device, wherein the main hoisting cable extends from the main hoisting winch via at least one sheave located at a main hoisting point to the main load suspension device;

[0074] a jib hanger having a support end, a midsection, and a luffing end opposite the support end of the jib hanger, wherein the jib hanger is fixed to the hoist end of the boom such that the support end and the luffing end are located at opposite sides of the boom, preferably the support end and the luffing end are each located away from the boom;

[0075] - a boom having a pivot end, a midsection, and a lifting end opposite the pivot end of the boom, wherein the pivot end of the boom is pivotally connected to the support end of the boom hanger so that the boom can pivot about a horizontal boom pivot axis between a boom raised position and a boom stowed position;

[0076] a secondary lifting assembly comprising a secondary lifting winch, a secondary lifting cable and a secondary load suspension device, wherein the secondary lifting cable extends from the secondary lifting winch to the secondary load suspension device via at least one sheave located at a secondary lifting point, preferably at the lifting end of the boom; and

[0077] - a jib luffing assembly comprising a jib luffing cable and a jib luffing winch, wherein the jib luffing cable extends from the luffing winch to the hoisting end of the jib for pivoting the jib about the jib pivot axis between the jib raised position and the jib stowed position.

[0078] In an embodiment of the vessel, in the boom storage position the boom of the crane is positioned substantially adjacent and parallel to the boom cradle.

[0079] In an embodiment of the vessel, the main lifting point is located at a support end of the jib cradle, the support end being preferably located remote from the top end of the boom.

[0080] In an embodiment, the vessel further comprises a boom bracket to support the boom of the crane in the boom storage position. Preferably, the boom bracket is configured so that when in the boom storage position, the boom extends substantially parallel to the deck of the vessel, i.e. in a substantially horizontal position.

[0081] In an embodiment, when the jib of the crane is in the jib stowed position, the jib extends substantially perpendicular to the deck of the vessel, i.e. when the boom is in the jib stowed position, the jib is in a substantially vertical position with the jib pivot end pointing upwards.

[0082] The present invention also provides a method for moving a crane into a crane storage position using a vessel according to the present invention. The method comprises:

[0083] - lowering the boom, i.e. pivoting it downwards to a boom storage position in which it is substantially parallel to the deck of the vessel; and

[0084] - lifting the boom, ie pivoting it upwards into a boom storage position in which the boom is preferably substantially perpendicular to the deck of the vessel and / or substantially perpendicular to the longitudinal axis of the boom.

[0085] The present invention also provides a method for installing a wind turbine using a crane according to the invention or using a vessel according to the invention, the method comprising the following steps:

[0086] - lifting the nacelle into position on top of a wind turbine mast using the boom and the main lifting assembly; and

[0087] - Lifting a wind turbine blade into position using the boom and the secondary lifting assembly.

[0088] Advantageous embodiments of the crane according to the invention and the method according to the invention are disclosed in the dependent claims and the description, wherein the invention is further illustrated and explained on the basis of a number of exemplary embodiments, some of which are shown in the schematic drawings. In the figures, components that correspond in terms of terminology or design and / or function are provided with the same last two digits. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Although mainly presented for illustrative purposes with reference to one or more drawings, any technical feature set out below may be combined with any independent claim of the present application, alone or in any other technically possible combination with one or more other technical features.

[0090] In the attached figure:

[0091] Figure 1 An embodiment of a vessel with a crane according to the invention is shown;

[0092] Figure 2 shows a top end of an embodiment of a crane according to the present invention with the boom in a boom storage position and the jib in a jib storage position;

[0093] Figure 3 shows the top end of an embodiment of a crane according to the invention with the boom in a boom raised position;

[0094] Figure 4 An exemplary embodiment of a crane according to the invention is shown when lifting a nacelle of a wind turbine;

[0095] Figure 5 Shown Figure 4 the tip of a crane lifting a wind turbine blade; and

[0096] Figure 6 A top end of a crane according to an exemplary embodiment of the present invention is shown, wherein the boom is depicted in both a boom raised position and a boom stowed position relative to the boom cradle. DETAILED DESCRIPTION

[0097] Figure 1 An embodiment of a vessel 1 according to the invention is shown with a crane 2. In the preferred embodiment shown, the vessel 1 is a jack-up vessel.

[0098] The vessel comprises a deck 3 and a foundation 4 mounted to the vessel. Furthermore, in the particular embodiment shown, the vessel comprises a boom bracket 5 for supporting a boom 7 of the crane 1 in the boom-stowed position. In the embodiment shown, the boom bracket 5 is configured such that, when in the boom-stowed position, the boom 7 extends substantially parallel to the deck 3 of the vessel 1, i.e., in a substantially horizontal position.

[0099] In the embodiment shown, the crane 2 is a leg-wrap crane comprising a crane housing 6, a boom 7, a boom luffing assembly 8, a main hoisting assembly 9, a jib hanger 10, a jib 11, an auxiliary hoisting assembly 12 and a jib luffing assembly 13.

[0100] The crane housing 6 is rotatably supported by the base 4 so that the crane housing can rotate relative to the base about a vertical rotation axis.

[0101] The boom 7 has a pivot end 14, a midsection 15, and a hoist end 16 opposite the boom's pivot end. The boom 7 is supported by the crane housing 6 so that it rotates about a vertical axis of rotation. The pivot end 14 of the boom 7 is pivotally connected to the crane housing 6 so that the boom can pivot up and down about a horizontal boom pivot axis.

[0102] The boom luffing assembly 8 comprises a boom luffing cable 17 and a boom luffing winch 18. The boom luffing cable 17 extends from the boom luffing winch 18 to the hoisting end 16 of the boom 7 to pivot the boom about a boom pivot axis.

[0103] The main hoisting assembly 9 comprises a main hoisting winch 19, a main hoisting cable 20 and a main load suspension device 21. The main hoisting cable 20 extends from the main hoisting winch 19 to the main load suspension device 21 via at least one sheave located at a main hoisting point 22.

[0104] The jib hanger 10 has a support end 23, a midsection 24, and a luffing end 25 opposite the support end of the jib hanger. The jib hanger 10 is fixed to the hoist end 16 of the boom 7 so that the support end 23 and the luffing end 25 of the jib hanger 10 are located at opposite sides of the boom 7. Moreover, in the illustrated embodiment, the support end 23 and the luffing end 25 of the jib hanger are located away from the boom 7.

[0105] The boom 11 has a pivot end 26, a midsection 27, and a raised end 28 opposite the pivot end of the boom. The pivot end 26 of the boom 11 is pivotally connected to the support end 23 of the boom hanger 10 so that the boom 11 can pivot about a horizontal boom pivot axis between a boom raised position and a boom stored position.

[0106] The secondary lifting assembly 12 comprises a secondary lifting winch, a secondary lifting cable and a secondary load suspension device. The secondary lifting cable extends from the secondary lifting winch to the secondary load suspension device via at least one sheave located at the secondary lifting point, preferably at the lifting end 28 of the boom 11.

[0107] The boom luffing assembly 13 includes a boom luffing cable 35 and a boom luffing winch. The boom luffing cable 35 extends from the luffing winch to the hoisting end 28 of the boom 11 so that the boom can be rotated about the boom pivot axis. Figure 3 The cantilever lifting position depicted in Figure 2 The cantilever arm is pivoted between the stowed positions depicted in FIG.

[0108] In the embodiment shown, Figure 1As depicted, the vessel 1 comprises a boom bracket 5 to support a boom 7 of the crane 1 in the boom-stowed position. The boom bracket 5 is configured such that the boom 7 extends substantially parallel to the deck 3 of the vessel 1 when in the boom-stowed position.

[0109] Furthermore, in the embodiment shown, when the boom 11 of the crane 2 is in Figure 1 and Figure 2 In the boom stowed position depicted in FIG, the boom extends substantially perpendicular to the deck 3 of the vessel 1, i.e. when the boom 7 is in the boom stowed position, the boom is in a substantially vertical position with the boom pivot end 26 pointing upwards.

[0110] In order to obtain Figure 1 1 , the boom 7 is lowered, i.e., pivoted downwardly, into a boom storage position in which it is substantially parallel to the vessel's deck. Furthermore, the jib 11 is raised, i.e., pivoted upwardly, into the boom storage position. In the preferred embodiment shown, in the boom storage position, the jib 11 is substantially perpendicular to the deck 3 of the vessel 1 and substantially perpendicular to the longitudinal axis of the boom 7.

[0111] Figure 4 An exemplary embodiment of a crane 1 according to the invention is shown when lifting a nacelle of a wind turbine using the main lifting assembly 9. Both the boom 7 and the jib 11 of the crane 1 are in a raised position. Thus, the crane is in a raised position, with the boom in a boom-raised position and the jib in a jib-raised position.

[0112] Figure 5 The secondary lifting assembly 12 is used to lift the blades of the wind turbine. Figure 4 Thus, the boom and main hoist assembly can be used to lift heavy loads, while the jib provides the crane with additional reach for relatively lighter loads.

[0113] Figure 6 A top end of a crane according to an exemplary embodiment of the present invention is shown, wherein the boom 111 is depicted in both a boom raised position and a boom stowed position relative to the boom cradle 110 .

[0114] In the embodiment shown, the boom hanger 111 is provided with a boom stop 133. In the stowed position shown, the boom 111 is pulled against the boom stop 133 by the boom luffing assembly to secure the boom in the stowed position.

[0115] In addition, Figure 6 In the exemplary embodiment shown, the main lifting point of the main lifting assembly of the crane is located at the support end 123 of the boom cradle 110 .

[0116] More specifically, in the illustrated embodiment, the crane is provided with an auxiliary main lift assembly that includes an auxiliary main lift point 134 that is also located on and supported by the jib hanger 110 .

[0117] Reference numerals

[0118] 01 Ship

[0119] 02 Crane

[0120] 03 Deck

[0121] 04 Base

[0122] 05 boom bracket

[0123] 06 Crane housing

[0124] 07 Boom

[0125] 08 Boom Luffing Assembly

[0126] 09 Main lifting components

[0127] 10 Cantilever hanger

[0128] 11 Cantilever

[0129] 12 auxiliary lifting components

[0130] 13 Cantilever pitch assembly

[0131] 14 Boom pivot end

[0132] 15 boom middle section

[0133] 16 Boom lifting end

[0134] 17 Boom luffing cable

[0135] 18 Boom luffing winch

[0136] 19 Main hoist winch

[0137] 20 Main hoisting cable

[0138] 21 Main load suspension device

[0139] 22 Main lifting point

[0140] 23 Cantilever hanger support end

[0141] 24 Cantilever hanger middle section

[0142] 25 Cantilever section pitch end

[0143] 26 Cantilever pivot end

[0144] 27 Cantilever middle section

[0145] 28 Cantilever lifting end

[0146] 33 Cantilever stop

[0147] 35 Cantilever luffing cable.

Claims

1. A crane for use on a ship, comprising: - a base to be mounted to the vessel or to be formed integrally with the vessel; - a crane housing, the crane housing being rotatably supported by the base so as to allow the crane housing to rotate relative to the base about a vertical rotation axis; a boom having a pivot end, a midsection, and a hoisting end opposite the boom's pivot end, wherein the boom is supported by the crane housing such that the boom can rotate about the vertical rotation axis, and wherein the boom's pivot end is pivotally connected to the crane housing such that the boom can pivot up and down about a horizontal boom pivot axis, the boom thereby being able to be lowered to a boom-stowed position and raised to a boom-hoisted position, wherein when in the boom-stowed position the boom is supported by a boom bracket of the vessel; a boom luffing assembly comprising a boom luffing cable and a boom luffing winch, wherein the boom luffing cable extends from the boom luffing winch to a hoisting end of the boom to pivot the boom about the pivot axis; a main hoisting assembly comprising a main hoisting winch, a main hoisting cable and a main load suspension device, wherein the main hoisting cable extends from the main hoisting winch via at least one sheave located at a main hoisting point to the main load suspension device; a jib hanger having a support end, a midsection, and a luffing end opposite the support end of the jib hanger, wherein the jib hanger is secured to the hoist end of the boom such that the support end and the luffing end are located at opposite sides of the boom; - a boom having a pivot end, a midsection, and a lifting end opposite the pivot end of the boom, wherein the pivot end of the boom is pivotally connected to the support end of the boom hanger so that the boom can pivot about a horizontal boom pivot axis between a boom raised position and a boom stowed position; a secondary lifting assembly comprising a secondary lifting winch, a secondary lifting cable and a secondary load suspension device, wherein the secondary lifting cable extends from the secondary lifting winch via at least one sheave located at a secondary lifting point to the secondary load suspension device; and a jib luffing assembly comprising a jib luffing cable and a jib luffing winch, wherein the jib luffing cable extends from the jib luffing winch to a hoisting end of the jib for pivoting the jib about the jib pivot axis between a jib raised position and a jib stowed position, wherein when the boom is in the jib stowed position and the jib is in the jib stowed position, the jib is in a substantially vertical position with the hoisted end of the jib pointing upward, wherein the boom hanger is provided with a boom stop, and wherein when the boom is in the boom storage position, the boom is pulled against the boom stop by the boom pitch assembly to secure the boom in the boom storage position.

2. The crane of claim 1 , wherein the jib is substantially perpendicular to the boom when the jib is in the jib storage position.

3. The crane of claim 1 , wherein the jib hanger is substantially perpendicular to a longitudinal axis of the boom.

4. The crane of claim 1 , wherein the boom luffing winch is mounted on the boom hanger to pivot the boom between the boom raised position and the boom stowed position.

5. The crane of claim 1 , wherein the primary lifting point is located at a supporting end of the jib hanger.

6. The crane according to claim 1, wherein a locking mechanism is provided for locking the jib in the jib storage position for securing the jib to the jib hanger.

7. The crane of claim 1 , wherein the boom comprises an A-frame, the A-frame comprising a left boom section and a right boom section, each boom section comprising a pivot end, a mid-section, and a hoist end, and wherein the two boom sections are connected at the hoist end and spaced apart relative to each other at the pivot end.

8. A vessel comprising the crane according to claim 1.

9. A ship comprising a crane, the ship comprising: -deck; - a boom bracket for supporting the boom of the crane in a boom storage position; - a base mounted to the vessel or formed integrally with the vessel; - a crane housing, the crane housing being rotatably supported by the base so as to allow the crane housing to rotate relative to the base about a vertical rotation axis; a boom having a pivot end, a midsection, and a hoisting end opposite the boom's pivot end, wherein the boom is supported by the crane housing such that the boom can rotate about the vertical rotation axis, and wherein the boom's pivot end is pivotally connected to the crane housing such that the boom can pivot up and down about a horizontal boom pivot axis, the boom thereby being able to be lowered to a boom-stowed position and raised to a boom-hoisted position, wherein when in the boom-stowed position the boom is supported by a boom bracket of the vessel; a boom luffing assembly comprising a boom luffing cable and a boom luffing winch, wherein the boom luffing cable extends from the boom luffing winch to a hoisting end of the boom to pivot the boom about the pivot axis; a main hoisting assembly comprising a main hoisting winch, a main hoisting cable and a main load suspension device, wherein the main hoisting cable extends from the main hoisting winch via at least one sheave located at a main hoisting point to the main load suspension device; a jib hanger having a support end, a midsection, and a luffing end opposite the support end of the jib hanger, wherein the jib hanger is secured to the hoist end of the boom such that the support end and the luffing end are located at opposite sides of the boom; - a boom having a pivot end, a midsection, and a lifting end opposite the pivot end of the boom, wherein the pivot end of the boom is pivotally connected to the support end of the boom hanger so that the boom can pivot about a horizontal boom pivot axis between a boom raised position and a boom stowed position; a secondary lifting assembly comprising a secondary lifting winch, a secondary lifting cable and a secondary load suspension device, wherein the secondary lifting cable extends from the secondary lifting winch via at least one sheave located at a secondary lifting point to the secondary load suspension device; and a jib luffing assembly comprising a jib luffing cable and a jib luffing winch, wherein the jib luffing cable extends from the luffing winch to the hoisting end of the jib for pivoting the jib about the jib pivot axis between the jib raised position and the jib stowed position, wherein when the boom is in the jib stowed position and the jib is in the jib stowed position, the jib is in a substantially vertical position with the hoisted end of the jib pointing upward, wherein the boom hanger is provided with a boom stop, and wherein when the boom is in the boom storage position, the boom is pulled against the boom stop by the boom pitch assembly to secure the boom in the boom storage position.

10. A vessel according to claim 9, wherein the boom bracket is configured such that the boom extends substantially parallel to the deck of the vessel when the boom is in the boom stowed position, i.e. the boom is in a substantially horizontal position.

11. A vessel according to claim 9 or claim 10, wherein when the boom of the crane is in the boom storage position, the boom extends substantially perpendicular to the deck of the vessel, i.e., when the boom is in the boom storage position, the boom is in a substantially vertical position with the raised end of the boom pointing upwards.

12. A method for bringing a crane into a crane storage position using a vessel according to claim 9 or 10, the method comprising: - lowering the boom, i.e. pivoting it downwards to a boom storage position in which it is substantially parallel to the deck of the vessel; as well as - lifting the boom, ie pivoting it upwards into a boom storage position in which the boom is substantially perpendicular to the deck of the vessel and / or substantially perpendicular to the longitudinal axis of the boom.

13. A method for installing a wind turbine using a crane according to claim 1 or using a vessel according to claim 9, the method comprising the steps of: - lifting the nacelle into position on top of a wind turbine mast using the boom and the main lifting assembly; as well as - Lifting a wind turbine blade into position using the boom and the secondary lifting assembly.

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