Field of the invention

The present invention relates to a knuckle boom crane in a launch and recovery system (LARS), comprising a foundation equipped with a tiltable lower boom and an articulated connected and tiltable upper boom, each driven by respective cylinders.

Background of the invention.

The present invention relates to a "Knuckle Boom Crane for ROV" (KBCR), which is designed to handle work class ROVs on a vessel or any suitable offshore

installation. The present invention may also be used with Autonomous Underwater Vehicles - AUV.

Disclosure of the state of art.

A knuckle boom crane appears similar to a standard crane, except that the boom articulates at the 'knuckle' near the middle, letting it fold back like a finger. This provides a compact size for storage and manoeuvring.

Knuckle boom cranes have become very common on offshore vessels as less of the deck space is blocked by the crane. A disadvantage is the higher power demand and increased maintenance due to the increased amount of moving parts.

Knuckle boom crane arms are much lighter than boom truck cranes, and they are designed to allow for more payloads to be carried on the back of the truck that it is mounted on. The majority of them are mounted behind the cab and leave the entire bed of the truck empty.

The cranes come with different types of control systems, such as: stand up, control from the ground, seat control, or radio remote control. The radio remote systems can start the crane as well as run the crane. They come equipped with a computer readout system that immediately gives readouts from the system if the crane is overloaded or not.

Knuckle boom cranes are also used in ROV applications. Other known solutions move the entire knuckle boom crane using a skidding solution or rotating the crane with a slewing ring. US 3884359 A relates to an articulated crane with an inner boom pivoted mounted on a supporting base, an outer boom pivotally mounted on the inner boom, and a pair of hydraulic cylinder assemblies, one for moving each of the booms,

respectively.

JP 2014009077 A relates to a telescopic boom with a trolley including a hoist winch device provided on a column post, and a return sheave for folding a wire rope, which is provided at the forward end of a tip boom. The wire rope drawn from a drum of the hoist winch device is wrapped round a sheave of a trolley through the return sheave, and the wire rope terminal is fixed to the base end part of the telescopic boom.

Objects of the present invention

It is an object to provide increased reach and flexibility of a knuckle boom crane, by having a wagon in the crane jib. Moving this along the jib gives the flexibility to split the ROV package on deck.

Advantages with the present invention is among other use of a "mono-leg" main support and structure, which gives less obstacles on deck compared to todays "A- frame".

The invention gives easier installation with only one foundation, and is more compact and less space demanding. The knuckle boom crane functionality for tilting and extended reach with integrated movable wagon for increased flexibility and reach gives the possibility to split the TMS (Tether Management System) from the ROV when on deck. Combined with a flexible docking head with in/out and left/right tilt results in a compact design, suitable for narrow hangars and road transportation.

Summary of the invention

The above objects are achieved by a knuckle boom crane in a launch and recovery system (LARS), comprising a foundation equipped with a tiltable lower boom and an articulated connected and tiltable upper boom, each driven by respective cylinders, wherein the upper boom comprises a movable wagon, said wagon being movable in a longitudinal wagon rail in the upper boom, and a tiltable docking head is connected to the movable wagon. The movable wagon may further comprise a protruding and rotatable docking head beam, onto where said tiltable docking head is connected. The wagon is preferable movable in the longitudinal wagon rail in the upper boom by a wagon cylinder.

The wagon cylinder is preferable in one end is connected to an end of the upper boom and in the other end connected to the movable wagon.

The movable wagon can be L-shaped.

A docking head sheave, for receipt of a cable from an operating winch, can be mounted to the protruding docking head beam of the movable wagon.

The foundation of the knuckle boom crane can be connected or mounted to a support base frame.

Preferable, the knuckle boom crane is of a mono-leg design.

Said wagon rail is preferable provided in a side face of the upper boom, and the movable wagon extends in horizontal direction from the side face of the upper boom.

Description of the diagrams

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:

Figure 1 shows a knuckle boom crane according to the invention.

Figure 2 shows the knuckle boom crane according to the invention in a retracted and park position.

Fig. 3 shows the knuckle boom crane according to the invention in a partially extracted position.

Fig. 4-6 shows the knuckle boom crane according to the invention in different motion sequences.

Fig. 7 shows the knuckle boom crane according to the invention combined with a base frame. Description of preferred embodiments of the invention

Other known solutions move the entire knuckle boom crane using a skidding solution or rotating the crane with a slewing ring, whilst the present invention can be welded or bolted onto deck.

The knuckle boom crane KBCR according to the invention is designed to launch and recover a remotely operated vehicle - ROV overboard from a vessel using the tiltable knuckle boom crane and an integrated movable wagon. The ROV is connected to the KBCR docking head when handled between deck and launch position. During ROV operation the KBCR may act as an overboard routing point between the ROV winch and the submerged ROV using an integrated docking head sheave.

As shown in the drawings the present knuckle boom crane 10 in a launch and recovery system (LARS) comprises in a known way a foundation 28 equipped with a tiltable lower boom 12 and an articulated connected and tiltable upper boom 14, each driven by respective cylinders 16, 18, preferable a pair of cylinders but also one cylinder for each boom may be used. The crane 10 according to the invention is preferable of a mono-leg design.

The foundation 28 can be fixed to a deck of for instance a vessel by welding or alternatively a bolted connection, and acts as connection point 24 for the lower boom 12 and lower boom tilt cylinders 16. Forces from the lower boom 12 are transferred to the foundation 28 via for instance bolted connections in the connection points 24 and the lower boom cylinder 16 brackets.

The lower boom 12 has a mentioned bolted connections to the foundation 28, and is tiltable using the lower boom cylinders 16. The lower boom 12 acts as connection point 26 for the upper boom 14 and upper boom tilt cylinders 18. Forces from the upper boom 14 is transferred to the lower boom 12 via the bolted connections in the connections points 26 and the upper boom cylinder 18 brackets.

The upper boom 14 has bolted connections in the connection points 26 to the lower boom 12, and is tiltable using the upper boom cylinders 18. The upper boom 14 act as connection point for a wagon cylinder 34, and comprises a wagon rail 32 for a movable wagon 30, which is integrated in the boom structure 10. Forces from the movable wagon 30 are transferred from wagon pads (or similar) to the upper boom rail 32 sliding surfaces and from the wagon cylinder 34 to the cylinder bracket. The wagon rail 32, and the wagon cylinder 34, is preferable provided on a side face 14a of the upper boom 14, such that the movable wagon 30 extends in horizontal direction from the side face 14a of the upper boom 14.

The movable wagon 30 is movable in the longitudinal wagon rail 32 in the

longitudinal direction of the upper boom 14, using the wagon cylinder 34, and is guided or slides along the upper booms wagon rail 32 using integrated wagon pads or similar.

The movable wagon 30 comprises an integrated rotatable beam 42 with interface to a docking head 40 and rotation actuators/cylinders. Rotation is controlled by two actuators/cylinders; one for docking head left/right motion and one for docking head in/out motion. Forces from the docking head 40 are transferred to the wagon 30 via the rotatable beam 42 and the two rotation cylinder brackets.

As seen in the drawings the movable wagon 30 can be somewhat L- shaped, but other designs are also possible. A docking head sheave 50, for receipt of a cable from an operating ROV winch (not shown), can be mounted to the docking head 40, and/or to the protruding docking head beam 42 of the movable wagon 30. The cable will run from the operating winch, over the sheave 50 and to a ROV or similar. The knuckle boom crane 10 according to the invention may further comprise or be connected to a support base frame 60, which can be equipped with driptray and sea fastening.

As seen in figure 2 the knuckle boom crane according to the invention is in a retracted and parked position, which gives a compact design. Fig. 3 shows the knuckle boom crane according to the invention in a partially extracted position, as an indication of increased reach and flexibility of a knuckle boom crane. As apparent from figures 4-6, showing the knuckle boom crane 10 according to the invention in different motion sequences, having a wagon in the crane jib and moving the wagon along the jib gives a multitude of reach and flexibility possibilities, and offers the flexibility to split the ROV package on deck.