METHOD AND DEVICE FOR RELEASABLY ENGAGING AND PLACING A LOAD

The invention relates to a method for placing a load such as a breakwater element and to a device for releasably engaging a load of this type. The invention also relates to a device for releasably engaging a load such as a breakwater element and in particular an accropode. The invention further relates to a lifting device provided with a device of this type.

In coastal engineering, use is widely made of concrete elements as armor protection on a breakwater or slope protection. Breakwater elements such as accropodes are known in the art. An accropode is a concrete element which can be used for reinforcing the coastal guard or for forming a breakwater at sea. The accropodes can be placed in the sea or just above it. The accropodes are in this case positioned in an interlocking pattern.

Many of these concrete elements, and in particular accropodes, should be placed in a specific manner in a pattern to ensure interlocking between the individual elements.

It is known in the art to place accropodes using a wire crane, wherein a loose accropode is engaged with a loop for positioning said accropode at a desired place. In this case, a diver is often present on or close to the desired location of the accropode in the sea bed in order to place, to observe and to guide said accropode, so that the accropode can be placed in the desired pattern. The presence of the diver means an increased safety risk and entails moreover additional costs during the manufacture of structures wherein accropodes are received.

To date, use has usually been made, for placing this sort of element under water, of wire cranes, such as are for example known from JP 04 173691 A. Relatively large freedom of movement of the lifted element in the horizontal plane is inherent to the use of a wire crane. The swaying results in a time delay. Further currents in the sea water can cause relative movement of the accropode during positioning for which the wire crane will need to compensate. In view of the fact that the individual elements should

be placed in accordance with a precisely predefined grid and in a specific manner, the assistance of divers during the placement under water is necessary.

The size of the concrete elements necessitates the use of lifting devices having sufficient capacity. The moving components of lifting devices of this type must, however, preferably not enter into contact with the water, in particular salt water owing to corrosion. The components of the lifting device can also be affected in a different manner by entering into contact with water.

After the positioning of the accropode, said accropode must be released from the lifting device. This often also necessitates the help of someone on site.

An object of the present invention is to provide a device and method wherein at least one of the aforementioned drawbacks is overcome. An object achieved by an embodiment of the invention is to speed up the positioning of the accropode. It is a further object of the invention to improve the positioning of the accropode. A specific object of a specific embodiment of the invention is to provide an embodiment wherein a diver is superfluous. A further specific object of one embodiment is to reduce the costs of placing the accropode.

At least one object is achieved, according to one aspect of the invention, by means of a method and device for placing a load such as a breakwater element and in particular an accropode, wherein said load is engaged by applying around the load a flexible member which is preferably shaped into a loop and thereby surrounding the load allowing lifting thereof. The applying of a flexible member and the forming of a loop around the load can take place in an efficient manner and permit rapid successive processing of various loads. The loop is part of the engaging unit of the device.

According to one embodiment of the invention, said loop is coupled to an articulated arm of a lifting device via a positioning component. This can be a crane. This is, in a particular embodiment, an excavator. In specific embodiments the positioning component can be configured to form a rigid connection between an end of the articulated arm and the load, so that movements of the articulated arm are converted

substantially directly into movements of the load. This improves the positioning with respect to wire cranes. An embodiment of the method comprises providing the articulated arm having a positioning component and forming the loop.

The method preferably further includes lifting the engaged load and positioning said load, wherein the positioning includes moving the positioning component with respect to the articulated arm. The load is in this case placed on a substrate, such as the water bed (that is to say, on the original bed or on the attached shore protection and/or breakwater). According to the invention, the positioning of the load, which must take place precisely, is carried out as a result of the fact that the positioning component can move with respect to the articulated arm of the lifting device. If the articulated arm is the arm of the excavator, this will be a rigid arm. The rigid arm is connected in a fixed position to the land or to a boat or dock. Precise positioning of the load is possible as a result of the fact that the positioning component can move with respect to the fixed point provided by the articulated arm. In contrast to the prior art wherein wire cranes are used, it is possible according to the invention to position the load via a component which is located closer to the load and which in one embodiment can be located just above sea level. The use of the articulated arm also eliminates the problem of the swaying of the load on long wires.

The specific combination of a flexible member for engaging the load and the use of the articulated arm permits precise positioning. This is a significant improvement over, for example, the known device according to JP 09 077460 A. The latter document explicitly does not permit the use of a loop by specifying that this device is intended to be used without wires.

The lifting device and specifically the excavator is operated from the land. This eases the supply of accropodes. Wheels of the lifting device allow easier positioning and possibly movement over relatively longer distances.

The positioning is further improved if the device further comprises at least tracking equipment such as a sonar unit and/or camera unit or a multibeam sensor, which tracking equipment is directed toward the engaging unit or engaged load for recording

data and in particular images of the engaging unit and/or the load, wherein said observed data and in particular the images can be sent to a remotely located display unit such as a screen for the observation thereof. The tracking unit can further comprise survey equipment. As a result, it is possible to observe the load from a distance, and to observe in particular the engaging unit. Further the survey equipment mounted at a distance from the engaging unit allows observing the surruounding and, and in particular whether the breakwater element, such as the accropode, is positioned in the desired position with respect to already positioned accropodes. The display unit is preferably located close to an operator of the lifting device.

Although also JP 09 077460 A seems to disclose a kind of tracking equipment, here the tracking equipment is mounted on the arm directly engaging the load.

The tracking equipment is preferably attached to the positioning component, that is to say, more distally from the articulated arm of the excavator. The tracking equipment is located at a short distance from the load, so that a complete image of the load and its environment is obtained. The tracking equipment is preferably attached to a rigid element, connected to the articulated arm, of the positioning component.

The tracking equipment can furthermore be suitable for recording the load while said load is located beneath the surface of the water. More particularly, the tracking equipment can be embodied to operate under water, so that the equipment continues to deliver usable images when the equipment is brought partly or wholly to below the surface of the water. In this way, very precise positioning can be attained, even in the case of relatively deep water. In specific embodiments, the tracking equipment is suitable for generating 3D images of the load, for example when the load is located under water; this can further promote precise positioning of the load.

In particular, the method and device are suitable for use in combination with a lifting device provided with a cabin in which the operator is present, wherein said operator has in his cabin a display device on which the observed images are reproduced. The operator can then by himself independently position the load at its desired place, because he has in his cabin the image of the position and of the environment thereof.

This allows a diver to be dispensed with at the site of the desired position of the accropode. This allows a saving to be made. The tracking unit, and in particular the image equipment, is able to track the position of the load and in particular the accropode. As a result, it is possible for the operator to carry out unaided from his cabin the entire method from picking up and engaging the load to placing and positioning said load. The positioning can take place unaided, even if this takes place under water. The release of the load can also be controlled remotely. The loop allows quick release of the load.

The coupling unit is preferably configured for coupling to an articulated arm of a lifting device such as an excavator. As a result, it is possible to bring the positioning part to a relatively fixed position, as a result of which it is possible using the cameras to take stable pictures of the load which is engaged by the engaging unit and is brought to the desired position. The articulated arm prevents swaying, which occurs when use is made of a wire crane to which an engaging unit for the accropode is fastened.

The tracking equipment comprises preferably at least two, preferably four cameras to be fastened to the device, and in one particular embodiment to the positioning component. It is also possible to fasten the cameras to the lifting coupling. As a result, a plurality of pictures are taken of the load from a plurality of angles.

The cameras are preferably attached to arms projecting outwardly from the lifting coupling or from the positioning component. The arms protrude outward, so that a complete image can be obtained of the load and the loop and the environment in which they are located. This facilitates the placing of the load. The term "to project outward" means, according to this description, to project in the horizontal plane.

By attaching the cameras to antennas of this type, it is possible to improve the angle of incidence of the cameras with respect to the load, as a result of which it is possible to obtain a better image of the load, and these improved images can be recorded and be sent to a remotely located screen, preferably in the cabin of the crane.

In a preferred embodiment, at least one camera is positioned on a gyroscope unit. The

gyroscope unit can control a plateau on which the camera is positioned. This further stabilizes the images from the camera.

According to the invention, a plurality of tracking units are preferably used together with the device. Provision may for example be made for a multibeam echo sounder, GPS facility and/or a height gauge, as a result of which the position of the load is known precisely and the placing of the load can in this way be controlled.

As auxiliary means for the tracking units and in particular for the cameras, lamps can be attached, in particular also on the arms projecting from the positioning component.

One of the objects of the invention is also achieved by means of the method according to the invention wherein a load is placed, wherein said load is engaged by applying around the load a loop formed by a flexible member, which loop is coupled to the articulated arm of a lifting device via a positioning component, and wherein according to the invention the specific applying of the loop includes moving the positioning component with respect to the articulated arm. According to the invention, the applying of the loop around the element or the load can take place by forming the loop and subsequently applying it around the breakwater element, wherein this precise applying can take place by moving the positioning component with respect to the articulated arm to which it is coupled.

The operator can be assisted by ground personnel. It is however possible to apply the loop, once formed, around the load without this requiring help on the ground. This allows a considerable saving to be made. It is possible for the operator of the lifting device to apply the loop around the load remotely via the articulated arm and by moving the positioning component with respect to the articulated arm.

The loop attached around the load can subsequently be used for lifting said load and positioning said load.

It is furthermore beneficial to extend the methods according to the invention by, after positioning the load, breaking said loop. As a result, the element can escape from the

loop and the engagement can be broken, as a result of which the element, which according to the invention can be positioned precisely, can be placed. As a result, it is possible to use the method without a further operator intervening in the process at the site of the desired location of the load. This leads to a further possible saving.

Activities in salt water have an adverse influence on the durability of the material, but excavators can be and are used to operate the articulated arm and use means suspended therefrom below water level.

It is furthermore advantageous, in particular for placing the load under water, that the method includes engaging the flexible member for forming the loop at a distance from the positioning component, wherein said distance is bridged by a second connecting member. The second connecting member forms preferably one, two or at least three connections from that positioning component. The connecting member can be flexible and/or rigid. The preferred embodiment presented here comprises three chains. Other preferable connecting members for bridging the additional distance can for example be tubular extensions made of steel or a mesh casing made of reinforcement steel. Use may also be made of plastics materials such as for example Teflon.

By means of the connecting member, it is possible to bring the loop of the flexible member further/deeper under water, and the distance under water or working depth can be further extended by extending the connecting member, in particular the three connections. It is particularly advantageous to use for the three connections a relatively rigid and flexible member such as a chain. Preferably, heavy chains and chain parts are used to bridge the distance.

Specifically by making use of a relatively rigid connecting member, the positional fixity of the positioning component, which is obtained by making use of the articulated arm, can be partly transmitted over the distance to be bridged. In contrast to a wire crane, use is made, for bridging the distance, not of one wire or flexible member but of a number of wires or flexible members, as a result of which swaying is significantly reduced.

It is furthermore advantageous to use for the loop a flexible member which is relatively flexible, such as a steel cable. As a result, the shape of the load to be engaged, such as the accropode, can be tracked, and the applying of the loop around said load can take place as a result of the fact that the flexible member yields sufficiently.

In an embodiment the loop is connected to the positioning component by two separate connections that is at two points separated by a distance. One is a fixed connection and one is a releasable connection.

An object according to the invention is also achieved by a device for releasably engaging a load such as a breakwater element according to the invention. The device according to the invention comprises a positioning component which can be movably coupled to an articulated arm of a lifting device such as a crane or an excavator. The positioning component is embodied to be moved for positioning the load. The relatively fixed position of the lifting device, which stands on land or on a boat, is transmitted via the articulated arm, which is rigid, to the positioning component which itself can be moved, e.g. rotated or tilted, even further in order to allow precise positioning of the load. The device according to the invention comprises a flexible member for engaging the load. The device according to the invention further comprises connecting means which are attached between the flexible member and the positioning component and are configured for connecting that flexible member to the positioning component. In this case, said connecting means are configured for engaging at least two parts of the flexible member for forming a loop. The loop can be used for engaging the load. It is possible for the load to be able to be received in the loop. This provides a device wherein the problem of the swaying load according to the prior art is eliminated while the easy engaging of the load, in particular the accropode, with a loop of a flexible member is maintained.

It is furthermore advantageous that at least one connecting means is embodied for releasably connecting the flexible member. As a result, it is possible to let the flexible member go. As a result, the loop can be broken. Precisely in this way, the load received in the loop can be freed. This last takes place when the load is brought into a desired position using the positioning component. The invention allows the release of the

breakwater element to take place by, for example, controlling the connecting means. The placing is controlled from a cabin of the lifting device, as a result of which the release can take place remotely without in this case, for example, a diver having to be present in the water for releasing the load.

The device according to the invention comprises preferably an actuator for providing a movable coupling to the articulated arm. Said actuator can preferably be connected to a drive. The actuator can be used to move the positioning component with respect to the articulated arm, as a result of which precise positioning of the load becomes possible. The actuator can be connected to a drive or to another power supply. The drive can be for example a hydraulic drive. Said source of hydraulic drive can be present on the lifting device and can be supplied to the actuator via the arm and a suitable coupling. In another embodiment, an independent power supply is present on the positioning component.

It is furthermore beneficial for the positioning component to comprise a frame part such as a plate or another assembly part which can be provided with a lifting coupling for coupling the device to the articulated arm of a lifting device. Said lifting coupling comprises at least one movable coupling piece for moving the frame part, and thus the load, with respect to the articulated arm of the lifting device. According to this embodiment, the drawback of the swaying which takes place in the case of a wire crane is avoided.

It is furthermore beneficial that the lifting coupling comprises a hydraulic coupling. As a result, controllable elements on the device can be provided with hydraulic pressure via the lifting coupling, and they can be controlled remotely, for example by the operator of the lifting device. It is for example possible to couple the connecting means via a hydraulic coupling which can be controlled from the lifting device. As a result, it is possible for the operator to be able to bring the connecting means from an engaging position to a free position, as a result of which the loop is broken.

In a preferred embodiment, the coupling piece comprises adaptor ears. The adaptor ears can form a connection between a jib piece and the positioning component or in

particular the frame part. The jib piece can be configured for providing a free movement with respect to a crane forwards and backwards. The adaptor ears can be configured for providing a free movement with respect to the crane to the left and to the right.

In a further embodiment, the coupling piece comprises at least one rotator. The rotator can preferably be attached between the adaptor ears and frame part. The rotator can provide a controlled, rotating, preferably hydraulically driven movement of the positioning part with respect to the crane. The rotator can also be provided with a hydraulic conveyor to pass a compressed and return current through the rotator. As a result, the supplied hydraulic coupling can be conveyed to other components of the device according to the invention.

It is furthermore beneficial to make the flexible member of steel wire. As a result, a sufficiently flexible member is obtained for grasping a breakwater element such as an accropode.

The load is preferably engaged using the flexible member. The flexible member is preferably shaped into a loop. Said loop can be partly preformed. The loop is attached around the load, so that for example loss of the load during lifting is as a result very unlikely.

The preforming of the loop can for example take place as a result of the fact that end parts of the loop are held at a defined distance from one another e.g. by means of an intermediate piece. This intermediate piece functions as a spacer. It is furthermore advantageous that the device comprises an intermediate piece for holding at least two parts of the flexible member, in particular two parts of the flexible member between which the loop is formed, at a predefined distance from one another, because as a result the size of the loop is defined more precisely and the loop can be kept to a suitable length. The suitable length of the loop is a length which makes possible both the engaging of an accropode and the raising of said accropode. The form of the accropode, in particular of an accropode I or II, is known to a person skilled in the art.

It is furthermore advantageous to connect the intermediate piece to the positioning component by means of a second connecting member such as a flexible member. As a result, the intermediate piece can be located at a distance from the positioning component. This makes it possible, in particular, to keep the positioning component, which can be provided with mechanical elements such as hydraulic elements, actuators and the like, in each case above water, whereas the extension is brought under water by means of the second flexible member and the loop of the first flexible member for positioning the accropode under water.

It is furthermore advantageous to attach a connecting means of the first flexible member to the intermediate piece. As a result, the position of at least one part of the first flexible member with which the loop is shaped is defined on the intermediate piece, and the position of the loop is determined more precisely.

It is furthermore advantageous to make the second member more rigid than the first flexible member. As a result, the connection of the positioning component to the intermediate piece is made more rigid than the loop which is formed by the first flexible member. As a result, the advantage of the invention, which is obtained by coupling to the articulated arm of a lifting device and the rigid coupling to the articulated arm via the lifting coupling via this flexible member, can be transferred to the intermediate piece, as a result of which the swaying known from the wire crane is to a large extent prevented.

The connection between the positioning component and intermediate piece can be further improved, in particular made more rigid and more positionally fixed, by making at least three connections formed by the second flexible member between that intermediate piece and the positioning component. By using three connections, it is possible to obtain a positionally fixed and for example non-rotating connection between the intermediate piece and positioning component. The second flexible member will have a hanging construction, and if three connections of this type are formed, swaying is significantly reduced.

It is furthermore beneficial to embody the releasable connecting means with a hydraulic

cylinder. The hydraulic cylinder can be fed in a hydraulic coupling which is fed via the articulated arm. As a result, this hydraulic cylinder can be activated from the crane by an operator. As a result, the releasing can be monitored from the cabin. The releasable connecting means is attached preferably to the positioning component and in particular to the frame part which is formed by a plate. As a result, it will remain above water, even if an extension with an intermediate piece is used.

The device can be provided with sending equipment for sending the observed data and in particular the images, but is in particular provided with electronic coupling means for making an electronic coupling, preferably via the lifting device, so that the images can be sent via the electronic connection via the articulated arm to a recording unit such as a screen in the cabin of the crane.

The invention also relates to a hydraulic crane comprising a chassis which is at least provided with an articulated arm to which a device according to one of the foregoing features is coupled.

The invention has been described hereinbefore and will be described hereinafter with reference to embodiments. It will be clear to a person skilled in the art that a plurality of embodiments are possible within the scope of the invention. The invention has been described with reference to a limited number of advantages. It will be clear that the device according to the invention will entail a plurality of advantages, which advantages will be implicitly present for a person skilled in the art. It is possible that the inventor will file a supplementary, divisional application directed at one of the implicitly or explicitly mentioned advantages.

The invention will now be described in greater detail with reference to the appended drawings, in which:

figure 1 is a view of a lifting device according to the invention;

figure 2 is a side view of a first embodiment of the invention;

figure 3 is a plan view of a first embodiment of the device according to the invention;

figure 4 is a view of the image forming with an embodiment of the invention;

figure 5 shows schematically a means for controlling the device according to the invention; and

figure 6 shows schematically another embodiment.

Figure 1 is a view of a lifting device 1 which, on a quay 2 on a coast 3, is at work under water 4, of which the water level 5 is shown. The lifting device 1 is a crane comprising in the embodiment shown a chassis 6 which is placed on a traveling chassis 7 and which is provided with a cabin in which an operator can be present for operating the crane 1. The crane 1 is provided with an articulated arm 10 consisting of three components 11, 12 and 13 which are connected to one another by means of hinges 14 and 15, and to the chassis of the frame 1 by means of a hinge 16. The respective parts are connected to one another via hydraulic cylinders 17, 18. The operator 8 in the cabin 9 can move the arms using known controls via levers and in this way bring the arm to a desired position.

Although the embodiment according to figure 1 shows a crane on the land, it is also possible to make use of a crane on a dock or on a ship or on another stable location.

The crane 1 is also referred to as an excavator. A lifting device of this type provides a rigid connection formed by the articulated arm 10 between the chassis 6, which is positioned stably on a land 2, of the crane and the end 20 of an arm. This will allow positioning to be carried out more precisely using an arm of this type than, for example, using a wire crane. The end 20 of the arm 10 can be positioned with a precision of a few centimeters. During the placing of a load, this higher precision can be used for placing coast-protecting elements such as accropodes 21 - 23. The crane end 20 is provided for this purpose with a device 30 according to the invention. A detail of the device 30 is shown in figure 2.

The coast-protecting elements or breakwater elements such as accropodes 21 - 23 are known in the art. A known accropode design has been developed by Sogreah. A plurality of types of coast-protecting elements are known. The accropode has been developed further and is inter alia known under the name "ecopode" or "accropode 2". The improved accropodes are provided with resistance surfaces.

A cross section and a side view of the accropode are shown in figures 1 and figure 2. The accropodes can be placed above or below sea water level 5. They can also be placed outside the coast. The accropodes must be placed in a predetermined grid which is known to a person skilled in the art. This requires precise placement.

Figure 2 shows in detail the device 30 according to figure 1. The end 20 of the arm 13 is shown at the top of figure 2. Located close to this end is the jib piece 31 which forms a connection of the end 20 of the arm 13 of the crane to adaptor ears 32, 33. The jib piece can be connected to the crane end via hinge parts 34, so that rotation about the axis 36 in the direction indicated by the arrow 35 is possible. The adaptor ears permit oscillation in the direction indicated by the arrow 37. The possibilities for swiveling in accordance with one of these movements are limited. The possibility is limited as a result of, for example, high friction. This movement can also be controlled, for example using a hydraulic cylinder which can be controlled from the cabin 9. The possibilities for swiveling do all provide a number of degrees of freedom for the controlled engaging of the accropode 26 and the positioning thereof.

The rotator 40 is located more distally from the end 20 of the articulated arm and past the adaptor ears 32, 33. This rotator can provide a controlled (hydraulically driven), rotating (360-degree) movement of the accropode clamp with respect to the crane. The rotator can also be embodied with a hydraulic conveyor to pass a compressed and return current through the rotator.

The compressed and return current conduits for hydraulic elements are not shown in the figures. It will be clear to a person skilled in the art that conduits of this type can be connected, on the arms 11, 12, 13 and via the jib piece and adaptor ears and the rotator, to parts on the frame 41. A person skilled in the art will be familiar with flexible

conduits. A person skilled in the art will also be familiar with working connections or coupling pieces for conduits of this type.

Located further distally from the rotator 40 is the positioning component 42, of which the frame part 41, formed by a plate, has a central function. Via the rotator, adaptor ears and jib piece, it is possible precisely to activate this positioning component from the cabin and in the process to allow the positioning component to assume a desired position. The desired position can be controlled to a precision of a few centimeters.

Figure 2 shows the device 30 while an accropode 26 is connected thereto. The accropode comprises inter alia an element which is circular in cross section, which is shown in figure 2 and is denoted by reference numeral 27. A loop 44, formed by a flexible member 45, is applied around this circular cross-sectional part and surrounds it. The flexible member can be a steel wire. The flexible member can assume a shape and in this case bend, as shown in figure 2. A flexible member which is suitable for this application has high bendability, and steel wire is therefore a good example. Close to an end 46, the flexible member 45 is connected to an eyelet 48 which is attached to the underside of the intermediate piece 47. Another end 49 of the flexible member 45 is connected to the eyelet 50 which is connected at the end to the frame part 41 via a chain 51 which is received in an opening of the intermediate piece 47.

A cylinder 56, of which the piston 57 is visible, is attached to the frame part 41. The cylinder can move in the direction indicated by the arrow 58. As a result, a pin, which projects into an eyelet of the chain 51, can be withdrawn, as a result of which the chain 51 is freed and as a result of which the loop 44 is broken. The cylinder 56 can be controlled, for example via the hydraulics, from the cabin 9. The loop can be formed by providing an eyelet of the chain 51 and closing the cylinder 56 by moving the pin 59 in the direction indicated by the arrow 58 and closing up the eyelet. This provides a particularly simple embodiment of a system for remotely freeing an accropode when said accropode is positioned in a suitable position.

A number of connecting means for a flexible member are located on an underside of the positioning component and in particular of the plate 41. In this embodiment, said

member is a second flexible member formed by chains. In the embodiment shown, three chains are clamped between the underside of the plate 41 and the intermediate piece 47. By virtue of the side view, only two chains are visible. The chains can be placed for example at the vertices of an equilateral triangle. The intermediate piece 47 can for example be round and the points connecting to the second flexible member can be spread uniformly around. As a result, three connections are formed between the frame part 41, which is stably connected to the end 20, and the intermediate piece 47. By making use of said chains, it is for example unlikely, certainly when a heavy load such as an accropode 26 is raised in the loop, that a connection of this type will start to sway.

As shown in figure 1 , the connections of the second flexible member 60 form an extension of the underside of the frame part 41 toward the loop 44. As a result, it is possible to work in deeper waters while the frame part 1 and the top parts are kept above the water level 5, whereas the flexible member 60 forms an extension below the water level together with the loop 44. This is shown in figure 1. It is possible further to extend the flexible member 60 for working on deeper grounds.

In the embodiment shown of figure 2, arms 80, 81 are attached close to adaptor ears 32 and 33, wherein a camera 84, 85 is attached to one end 82, 83, wherein the camera is directed downward and wherein the field of vision is denoted by 86, 87. The cameras

84, 85 are configured for recording the accropode 26, which is received in the loop, and can assist in positioning the accropode 26 in the desired grid as a result of the fact that the image collected by the cameras 84, 85 can be sent to the cabin 9 where the operator views said images. This enables him to see from a distance where the accropode is positioned at that moment. As a result, it is possible for the operator 8 to be able to carry out from his cabin 9 the entire operation of positioning and placing the accropode.

Other survey equipment can also be used. Further equipment for recording data relating to the accropode during the placing can be for example GPS data relating to the position and/or height position data. Suitable devices can be added to the device according to the invention. As a result of the fact that the device is stabler compared to other devices according to the prior art for positioning an accropode, more rapid

positioning can be obtained.

The adaptor ears remain, like the frame part 41, above the water level 5 and there is thus obtained from the cameras 84, 85, mounted on the antennas 80, 81, an image of the water and of the accropode 26 located therein.

Figure 3 shows the embodiment with four arms 80, 81, 90, 91. Each arm is provided with a respective camera. Figure 4 then shows the camera pictures and a plan view of previously positioned accropodes may also be seen. The pictures from cameras 1 to 4 are represented by the circles 100, 101, 102, 103 which are indicated by dot-dash lines. The previously positioned accropodes 105, 106, 107 can be seen via the cameras on monitors attached for this purpose in the cabin.

In an embodiment the observed data is collected in a sonar unit. This allows measurements of distances. It will allow to obtain an image of the load and its surroundings including relative distances. The distances can be shown in color on a display unit disposed in the cabin of the operator.

The accropode 111, which is received in the loop 110, is visible and is located centrally with respect to the four cameras. Figure 4 is a schematic overview of the positioning of the accropode. The actual accropode position can differ from the position shown in figure 4.

Figure 3 shows the connecting points 120, 121 , 122 of the chains 60 which hang between the assembly plate 41 and intermediate piece 47. The connecting places are uniformly distributed around a center point.

The engaging of an accropode according to the invention will now be described. First of all, it will be possible for the loop to be formed by the operator. The operator can for this purpose leave his cabin. The loose end of a steel wire, or the extension piece formed by a chain 51, can be inserted manually by the operator into a hole 130 in the assembly plate and the hydraulic cylinder 56 can be closed by attaching the pin 59 in a chain. As a result, a new loop is formed. The cylinder 56 can for example be operated

remotely by the operator. The length of the flexible member 45 and any extension with the chain 51 has a suitable length which can be defined in advance by the operator. The length strikes a compromise between a loop which, on the one hand, is sufficiently large to be attached around the accropode and, on the other hand, is sufficiently small to stably surround and not to let go the accropode received in the loop.

In an embodiment, not shown, the free end of the flexible element can be moved in order to tighten the loop. In an embodiment one end of the flexible element is connected to a winch and that end can be winded allowing tightening of the loop. A suitable actuator can be used.

The operator can return to the cabin 9 and carry out from there the further operations for positioning the coast-protecting elements. As a result of the fact that the length of the steel wire is such that the loop can be received therein, the operator can activate from his cabin the articulated arm and the elements of the lifting coupling in the usual manner through the adaptor ears 32, 33, jib piece 31 and rotator 40 in order to attach the loop around a part of the accropode. Specifically as a result of the fact that the articulated arm is a rigid arm, the loop can be precisely controlled from the cabin.

As it hangs, the element is raised by the crane and brought into or onto the water. When it is located above the end location, the position of the accropode part can be precisely tracked by means of the sensors and in particular the tracking units as formed by the cameras. In addition, a place-defining system can be used for precisely tracking the position. In addition to cameras, lights and the like can also be attached to the arms 80, 81, 90, 91. The cameras can be configured with particular properties for looking under water. Use may be made of cameras which react to visible light, to infrared and to other wavelengths. This allows a better picture of the underwater situation to be obtained.

In one embodiment of the invention, an underwater camera is used. In another embodiment of the invention, use may be made of an underwater camera which is detached from the device. The underwater camera can be for example an unmanned submarine.

In one embodiment of the invention, the loop is formed after the accropode is partly surrounded by the flexible member.

As a result of the fact that the device according to the invention is embodied with a number of coupling pieces in the lifting coupling, the position of the accropode can be controlled precisely and it is particularly beneficial that the degree of freedom permits inter alia rotation in the horizontal plane. The rotation, generated by the rotator 40 according to the embodiment of figure 2, is transmitted via the frame part 41 to the chains 60 which integrally transmit this movement to the intermediate piece 47. The accropode, which is engaged by the loop 44, will subsequently also track the movement of the rotator. As soon as the element is brought to a correct position, the hydraulic cylinder 56 can be drawn in, as a result of which an eyelet of the chain 51 is freed and the loop 44 is broken.

Other equipment which can be added to the tracking unit of the invention is for example a multibeam apparatus.

Figure 5 shows schematically a control system 150 of a hydraulic crane such as the excavator 1 according to figure 1. All data are collected in a central processing unit 151. The data can derive from the cameras 152 - 155. In one embodiment, there is an electrical connection between the cameras and the central processor 151. In another embodiment, the data can be sent wirelessly. Other data from the tracking equipment, such as a GPS receiver 156 which can be attached to the intermediate piece 47 or to the assembly plate 41, can also be coupled to the central processor 151. The multibeam apparatus 157 is also represented. A further sensor can be a height sensor 158 which is also connected to the central processor 151. From the central processor 151, the recorded images can be sent via a data line 159 to a screen 160 on which the four recorded images can be depicted. This screen can be present in the operator's cabin 9.

Figure 6 shows a further embodiment of the present invention. In this embodiment, the aforementioned arms 80, 81 are omitted and replaced by a single, elongated support structure 131. For the remainder, the structure corresponds to the structure described hereinbefore in conjunction with figures 1 and 2 and a detailed description thereof is

therefore also omitted here. The support structure 131 is fastened to the aforementioned part 31 (the jib piece) of the frame of the positioning component and comprises a first elongated support part 133 (length (1) characteristically between 3 m and 4 m), which in the illustrated embodiment is embodied as a lattice structure, and a second support part 134. The second support part is less elongated than the first support part and is provided with a ballast element 135 to keep the entire support structure 131 more or less in balance. The support structure 131 extends in use in a direction substantially parallel to the crane end 20, in such a way that the relatively short second support part 134 is located on the side of the articulated arm of the crane, that is to say, on the coast side, and the first support part 133 is located on the opposing side, that is to say, on the sea side. This arrangement of the parts of the support structure 131 benefits the maneuverability of the device.

The first support part 133 is provided with a number of cameras, such as cameras 136 and 137, which are placed at various distances with respect to the positioning component and are directed toward any load. The cameras are preferably underwater video cameras, so that said cameras can readily be used under water. The cameras allow video images to be sent to the operator and thus to assist said operator in the positioning of the load. Furthermore, a sonar unit 138 can be present at the end of the first support part 133. The sonar unit can be used to send to the operator 2D or 3D sonar images which, in isolation or in combination with the pictures from the cameras, can be helpful during the positioning of the load. In particular in turbid water, in which the camera pictures can sometimes provide too little information about the position of the load, the use of the sonar unit can lead to good results.

Although the invention has been described with reference to preferred embodiments, it will be clear to a person skilled in the art that various embodiments are possible within the scope of the invention. The invention is not limited to the above-described preferred embodiment, but is limited merely by the appended claims and encompasses all equivalents thereof.