NL2020157B1 - Dredging tool - Google Patents

Abstract

The invention relates to a dredging implement comprising a row of at least 3 drag heads, designed in such a way that they can be moved over a water bottom in one direction perpendicular to the drag direction of the row. The drag heads individually and / or in a group of drag heads are resiliently connected to a rigid structure, which rigid structure is positioned above the row of drag heads. The rigid structure is resiliently connected to a bridge positioned vertically above the rigid structure. The vertical distance between rigid construction and bridge is adjustable. The bridge is connected by means of a plurality of linear actuators to the rigid structure positioned underneath such that, in use, the linear actuators exert an adjustable and vertical pressing force on the drag heads.

Description

Patent center

Θ 2020157 (21) Application number: 2020157 (22) Application submitted: December 22, 2017 @ Int. CL:

E02F 3/92 (2018.01) E02F 5/10 (2018.01) E02F 7/02 (2018.01) E02F 9/06 (2018.01) E02F 5/28 (2018.01) B63C 11/00 (2018.01) E21C 45/00 (2018.01)

(30) Priority: (73) Patent holder (s): 23 December 2016 NL 2018070 CARPDREDGING IP B.V. in Papendrecht. Application registered: (72) Inventor (s): July 2, 2018 Jan Lanser in Papendrecht. (43) Application published: July 4, 2018 (m) Authorized representative: ir. M. Cramwinckel in Steenwijk. (47) Patent granted: October 3, 2018 (45) Patent issued: November 19, 2018

Dredging tool © The invention relates to a dredging tool comprising a row of at least 3 drag heads, designed in such a way that they can be moved over a water bottom in one direction perpendicular to the drag direction of the row. The drag heads individually and / or in a group of drag heads are resiliently connected to a rigid structure, which rigid structure is positioned above the row of drag heads. The rigid structure is resiliently connected to a bridge positioned vertically above the rigid structure. The vertical distance between rigid construction and bridge is adjustable. The bridge is connected by means of a plurality of linear actuators to the rigid structure positioned underneath such that, in use, the linear actuators exert an adjustable and vertical pressing force on the drag heads.

NL Bl 2020157

This patent has been granted regardless of the attached result of the research into the state of the art and written opinion. The patent corresponds to the documents originally submitted.

Dredging tool

The invention relates to a dredging implement comprising a drag head.

An example of a dredging equipment that is provided with a trailing head are trailing suction hopper dredgers as described in WO2013 / 009172. This publication describes a drag head connected to a heel segment. Towing head and heel segment can be dragged over a water bottom by a floating vessel. The excavated soil through the drag head is transported to the floating vessel through a transport tube. Other examples of drag heads are described in EP1653010.

A disadvantage of the dredging tool described above is that the capacity can be improved. Another drawback of the current trailing suction hopper dredgers is that the positioning of the trailing heads on the water bottom is poor and inaccurate, making it difficult to dig a well-defined part of the water bottom. Furthermore, the pressing force on the bottom is determined by the weight of the drag head and heel segment. It is not possible to increase this pressure force.

US4232903 describes a frame movable over the seabed which is provided with several drag heads. A drawback of this construction is that the pressing force of an individual drag head is determined by the underwater weight of the framework.

US2016 / 0002879 and US4141159 describe a type of drag head which is used for extracting minerals from the seabed. The pressure force of the drag head on the seabed is determined by the weight of the drag head. Because the installations do not have dredging as their goal, this is also not relevant for these installations.

The present invention provides a dredging tool that can excavate a detained piece of water bottom and wherein the pressing force of an individual drag head on the sea bottom is adjustable. The following dredging tool provides for this.

Dredging tool comprising a row of at least 3 drag heads, such that in use the dredging tool is moved over the water bottom in a direction that is perpendicular to the direction of the row of drag heads, the drag heads being connected to a rigid structure which rigid structure is positioned above the row of drag heads and wherein the drag heads are connected to the rigid structure by means of a resilient connection such that a drag head can absorb a vertical load on the drag head independently of another drag head or drag heads, wherein the rigid structure is resiliently connected to a bridge positioned vertically above the rigid structure and wherein the vertical distance between rigid structure and bridge is adjustable, and wherein the bridge is connected by means of a plurality of linear actuators to the rigid structure positioned below such that in use the linear actuators exert an adjustable and vertical pressing force on the drag heads.

With the dredging tool according to the invention it is possible to use several drag heads simultaneously and thus excavate a larger surface of a water bottom. Furthermore, the pressure force of a drag head on the water bottom can be adjusted from the bridge. By fixing the bridge relative to the seabed or from a floating vessel, a higher pressing force can be achieved than in the known dredging installations. In use, the dredging tool is moved over the water bottom in a direction that is perpendicular to the direction of the row of drag heads. Because the drag heads are connected to the rigid construction independently of the other drag heads, it is possible to move the row of drag heads over a water bottom which comprises irregularities. In the case of an unevenness, the drag head can move vertically upwards to absorb the vertical impact load on the individual drag head while the remaining drag heads continue to follow the water bottom. In this way, several drag heads can simultaneously excavate a ground-water mixture from an uneven water bottom. The drag heads according to the present invention can be positioned well on the water bottom, so that the accuracy and thus the quality of the underwater work is better than with the known trailing suction hopper dredgers.

In this description, terms such as horizontal, vertical, above and below will be used to describe the invention and its preferred embodiments. This is based on the invention in its position in normal use. For example, when used to excavate a horizontal water bottom. Water bottom is any surface of a solid that is submerged in water. This can be the seabed or a bottom in a sea arm, lake or river. The longitudinal is understood to mean the direction in which the rows of digging means are moved over a water bottom. By the term transverse, transverse force or transverse direction is meant a direction that is perpendicular to the longitudinal direction and in the horizontal plane. By the term sinkable is meant that a sinkable structural element can sink to the water bottom and can also rise back to the water surface.

The dredging tool according to the present invention can be used to excavate a portion of a water bottom, for example to increase the water depth and / or to extract minerals.

A row of drag heads preferably comprises at least 3, preferably at least 4 and more preferably at least 5 drag heads. The maximum number of drag heads per row will depend on what is still possible mechanically. This maximum is preferably 50 drag heads per row and more preferably 30 drag heads per row.

In use, a drag head is moved in one direction over the water bottom. This direction is also called the towing direction. A row of drag heads is preferably designed so that they can be moved over a water bottom in one direction perpendicular to the direction of the row. In a preferred window liner, the dredging tool is provided with a second row of drag heads of at least 3 drag heads, the drag heads being connected to a second rigid structure, the second rigid structure being positioned above the second row of drag heads and wherein the drag heads are connected to the rigid by means of a resilient connection construction are connected such that a drag head and / or a group of drag heads can absorb a vertical load on the drag head and / or on the group of drag heads independently of the other drag heads and / or groups of drag heads. Another possibility for circumventing large and / or extreme obstacles of the water bottom is to connect the rigid structure so as to be rotatable about the axis in the transverse direction and / or about an axis in the longitudinal direction. The rotatable connections are preferably provided with torsion springs to return the drag heads to their original position. Even more preferably, the number of drag heads of the second row is the same or substantially the same as the number of drag heads of the first row.

The drag heads can be connected individually or in a group of drag heads, for example a group consisting of two or three drag heads, to the rigid structure. In that case, a group of drag heads can absorb a vertical load on the group independently of the other groups of drag heads. Preferably, drag heads are connected to the rigid structure by means of a resilient connection such that a drag head can absorb a vertical load on the drag head independently of the other drag heads.

The drag heads of this second row can be designed such that the drag direction of the second row is the same as the drag direction of the first row. This can be advantageous in case a drag head in a row functions less well. The drag head in the adjacent row can then dig off the water bottom which has been missed by the poorly functioning drag head. Furthermore, an adjacent row of drag heads can be arranged offset. Staggered is here understood to mean that a drag head of a row is positioned at the height of the space that is present between the drag heads of an adjacent row. By spreading the drag heads in a row relative to the adjacent row, a water bottom is excavated as efficiently as possible. Pieces of water bottom which are located between drag heads and as a result cannot be efficiently dug off by the relevant row of drag heads are then ravaged by the drag heads of the row behind.

The towing direction of the second row is preferably opposite to the towing direction of the first row. Such a second row of drag heads and the second rigid structure connected thereto is preferably positioned parallel to the first row of drag heads and the rigid structure connected thereto, the drag direction of the drag heads of the first row being opposite to the drag direction of the drag heads of the drag heads of the second row. Preferably, one row and the rigid structure connected thereto can move in vertical direction with respect to the other row and the rigid structure connected thereto. This is advantageous if the two rows of drag heads are moved back and forth over a water bottom, wherein the row of drag heads with a drag direction opposite to the movement of the rows of drag heads can be placed vertically higher. In this way the row with opposite towing direction will not hinder the movement of the other row over the water bottom.

The dragging head can in principle be provided with a suction opening for ground-water as described in, for example, WO2014 / 098600, EP1609916, EP2342385, US4123859, US4150502, GB2128663, NL8501357, US1840606, EP1786982, JP60062567, JP60063089, US12

US2011239493 and US2011296720. The drag head can be provided with water jets and / or with digging teeth.

The drag head preferably comprises a visor which is rotatably connected about a horizontal axis to a suction nozzle which in turn is directly or via one or more intermediate parts vertically resiliently connected to the truss structure and wherein visor and suction nozzle together form a suction opening for a ground-water mixture of the drag head.

Preferably, the visor and suction nozzle are connected directly or via one or more intermediate parts by means of a rotating connection to the rigid construction such that visor and suction nozzle can rotate about an axis extending in the towing direction with respect to the framework or the optional intermediate parts. The rotating connection is preferably provided with springs in the tangential direction.

The drag head is also connected to a suction pipe for draining the ground-water mixture. This suction tube is connected by means of a fluid connection to a suction pump and the suction tube preferably has a variable length. An advantage of the above-described preferred embodiment of the drag head is that the load exerted by the water bottom on the drag head is not directly passed on to the suction pipe. The load is partly absorbed by the rotating movement of the visor and suction nozzle, the springs in the rotating connection and the springs in the spring connection between the drag head and the rigid construction. In this way a row of drag heads can be moved over a water bottom with unevenness with a minimal load on the individual drag heads or groups of drag heads.

The drag heads are preferably demountably connected to the rigid structure. In this way a less effective drag head can easily be replaced by a better functioning drag head. The bridge will be lifted by means of hydraulic cylinders.

The invention also relates to the following drag head which can be used advantageously in the dredging installation according to the present invention. The drag head comprises a visor which is rotatably connected about a horizontal axis to a suction nozzle, whereby visor and suction nozzle together form a suction opening for a ground-water mixture of the drag head and wherein the suction nozzle is connected via a rotating connection to a suction tube such that visor and suction nozzle can rotate about an axis extending in the drag direction of the drag head and wherein the rotary connection is provided with shock-absorbing means in the tangential direction of the rotary connection. The rotating connection preferably comprises two parts, a first part being connected to the visor and suction nozzle and a second part being connected to the suction pipe and wherein both parts are provided with an opening for passage of the soil / water mixture which, in use, is passed through the the drag head is suctioned and wherein the first part comprises a circular part which is provided with recesses and tilting and the second part comprises a circular part which is provided with recesses and tilting such that when the first part and the second part are joined to the rotating connection the tilting of the first part fits into the recesses of the second part and the tilting of the second part fits into the recesses of the first part and wherein in this circular space the shock-absorbing means are present between tilting of the first part and the tilting of the second part. The shock-absorbing means can for example be rubber blocks and preferably springs.

A free-standing excavating means is preferably present at the ends of the first and / or second row of drag heads. This excavating means can for instance be a wheel of a drum cutter which is driven by a motor. This excavation means has the function of preventing the dredging tool from getting stuck in the trench dug by the dredging tool itself. This excavating means can be provided with a suction tube and is preferably not provided with a suction tube.

In order to create a less sloping stable slope on either side of the trench which is dug by the dredging tool, it is advantageous to also provide the dredging tool with an excavating means that can be extended horizontally in the direction of the row. This excavating means is positioned above the row of excavating means and is preferably part of the rigid structure. The excavating means is preferably a digger wheel or drum cutter. If the rows of excavating means excavate the same surface of the water bottom several times by a reciprocating movement, the rigid construction and excavating means will move downwards in its self-dug trench. By now moving the horizontal excavating means in the direction of the rigid construction with each movement downwards, a less sloping slope is obtained.

Any loosened soil that sinks to the self-dug trench can be discharged there by the drag heads of the dredging tool.

The rigid construction can be a box construction and preferably a lattice construction. The above-mentioned rigid structure is resiliently connected to a bridge, which bridge is vertically positioned above the rigid structure and wherein the vertical distance between rigid structure and bridge is adjustable. This bridge can be positioned at a fixed vertical position with respect to the water bottom as will be described in more detail below. By moving the rigid structure vertically downwards relative to the bridge, an adjustable and vertical pressing force of the drag heads on the water bottom can be realized. This is not possible with the current dredging equipment in which the dragging head is advanced from a floating vessel as described in the aforementioned WO2013 / 009172 and also in WO2011 / 003438. This is advantageous because now harder water bottoms can be excavated and / or the reaction forces of any water jets can be absorbed better. The drag heads can also be moved upwards in the event that one or more drag heads has become attached to the water bottom.

The bridge can have a timber frame construction. If the bridge part forms part of a sinkable dredging tool, the bridge preferably has a box construction. The box-shaped construction can, for example, be filled with a gas to allow the dredging tool to float or rise from the water bottom. The bridge is preferably resilient and connected by means of a plurality of linear actuators to the rigid structure positioned underneath such that, in use, an adjustable and vertical pressing force can be exerted on the excavating means. The spring constant of one or more springs with which the drag heads are resiliently connected to the rigid structure is preferably smaller than the spring constant of one or more springs with which the rigid structure is connected to the bridge.

Such a bridge can form part of a floating vessel, the bridge being resiliently connected to a floating vessel by means of a plurality of springs and linear actuators which extend downwards and towards the bridge from the floating vessel. The bridge is preferably connected to at least four linear actuators, the ends of these actuators being connected to the floating vessel by means of a ball joint and connected to the bridge by means of a ball joint. At least one spring is included in this connection. The connection with the floating vessel is preferably movably connected in the direction of the row of drag heads to accommodate the swinging movement of the floating vessel. Preferably movably connected by a linear actuator. This actuator can keep the actuator that extends to the bridge as vertical as possible.

By moving the floating vessel in a direction perpendicular to the rows of drag heads, a well-defined rectangular part of the water bottom can be dug off. If the excavation installation is provided with the two rows of towing heads with opposite towing direction as described above, the floating vessel can sail to and fro. In this case, each time the rigid construction with the drag heads connected opposite to the sailing direction is positioned vertically upwards and the row of drag heads with the drag direction equal to the sailing direction is placed on the water bottom. Sailing the floating vessel is understood to mean a displacement which can be effected by screws, thrusters and / or anchors. This method of excavating from the water bottom can be advantageous in narrow waterways where turning the entire vessel would not be possible.

The above-described connection with the floating vessel makes it possible for the pressing force of the excavating means on the water bottom to be kept reasonably constant and high in a situation where the vessel moves due to swell on the waves and / or in the event of an irregular bottom slope.

If the excavator is used in deeper water, it is advantageous to use the following excavator. In this embodiment, the movable bridge can move in a horizontal and longitudinal direction along two frame members positioned parallel and in the longitudinal direction which form a frame with two cross members. The framework is preferably rectangular because this simplifies the construction.

Such a framework has four corners. By corner point is meant any construction which is suitable to be connected to the frame beams and the cross beams. The construction is preferably also suitable for being provided with support means and anchoring means. The construction for the corner points can for instance be a box-shaped construction or a lattice construction. Box-shaped constructions are advantageous because they can optionally be filled with water and gas in order to allow the framework to float, sink or rise. The corner points of the framework are therefore preferably provided with means for being able to anchor the rectangular frame with the ground. These means are preferably screw anchors and / or suction anchors.

The corner points of the framework are furthermore preferably provided with a support means. Such supporting means are preferably one or more wheels, tracks or a carriage. With these supporting means, the framework can be moved over the water bottom while the framework remains in the sunk state. The supporting means are preferably connected to the corner points by means of linear actuators which are adjustable in length. With these actuators, the frame can be positioned in the desired position, for example horizontally, relative to the water bottom. This is advantageous in the case that the dredging tool has finished digging the surface of the water bottom which is under the installation. The dredging tool can then move in a simple manner to a surface of the water bottom which still has to be excavated. For moving it can be advantageous to also provide the dredging tool with one or more means to move the rectangular frame horizontally. These means can preferably be so-called thrusters and / or the already mentioned tracks and / or driven wheels.

The movable bridge is preferably connected to the two cross beams by means of winch cables, which winch cables enable horizontal movement of the movable bridge along the two parallel positioned framework beams. By applying a tension to the winch cables it is possible to move the movable bridge. The tensioned winch cables also give the framework a good dimensional stability. This is advantageous not only when the framework is used during the excavation of a water bottom but also during the vertical and horizontal transport of the framework with the row or rows of drag heads connected thereto from and to the water bottom.

Preferably, each of its ends of the movable bridge comprises a guide sleeve. One of the two parallel frame members extends through the opening of each of the tubes so that the movable bridge can move in the longitudinal direction of the frame members. The guide sleeves are preferably provided on their inside with resilient wheel sets and / or resilient rollers which in use can give the frame beams 6 kinematic degrees of freedom relative to the guide sleeve. Such an embodiment is advantageous to prevent the movable bridge from jamming when it moves along the frame beams. The guide tubes can be provided on their underside with support means to prevent the frame beams from bending. Such supporting means are preferably one or more wheels, tracks or slides.

The ends of the framework beams and the ends of the cross beams are preferably resilient and connected with a ball joint to a corner point in each of the four corners of the framework. This results in that the forces on the drag heads are not only absorbed by the spring wheel sets in the bridge part, but also by the springs between the frame beams and the cross beams and corner points. If the framework is fixed on the water bottom by means of anchors connected resiliently to the water bottom, a very form-retaining framework is obtained with retention of 6 kinematic degrees of freedom. In this anchored state, the extreme load on the drag heads and / or on the movable bridge can be absorbed by the framework. The optional support means are also resiliently connected to the corner points to absorb the impact load when the framework lands on the water bottom. The combination of the springs and ball joints in the connections with the corner points and the resilient support means results in that the framework can properly follow an irregular water bottom when it is transported over the water bottom. Also during the horizontal transport of the framework on the water bottom, the framework has 6 kinematic degrees of freedom which are advantageous to be able to absorb the forces that are then exerted on the framework. The dimensional stability of the framework during the horizontal transport on the water bottom is realized by the pre-stress in the winch cables on either side of the bridge and by the resilient guide means included in the bridge part.

The above-described dredging tool comprising the framework can be connected to a floating vessel by means of linear actuators provided with ball joints which connect the corner points of the frame work to the floating vessel. The dredging tool comprising the framework can also be used independently in, for example, shallow water. In shallow water the framework can be fixed in the water bottom by means of screw anchors and then jacked up. The cross beams and the framework beams can herein be located above the water surface, the rows of excavating means excavating the shallow water bottom.

The linear actuators described above can be electromechanical actuators and preferably hydraulic cylinders.

The dredging tool comprising the framework as discussed above is preferably submersible if the water depth makes the use of a floating vessel less attractive and / or when there is a need for a larger and / or constant pressing force on the excavating means. To this end, preferably the framework beams, cross beams, the corner points and / or the movable bridge comprise compartments which can be filled with gas and / or water in order to allow the dredging tool to float, sink to a water bottom or to rise from a water bottom . When sinking and taking off the framework, thrusters can advantageously be used to hold the framework in the desired orientation and to increase stability. The framework is preferably provided with propulsion means so that the framework can move floatingly. These propulsion means can be the aforementioned thrusters.

The dredging tool comprising the sinkable framework can therefore be used in shallow water, normal dredging depths and very large water depths. Because the framework can float, it can easily be moved. The applicant believes that such a dredging tool has not been described before and is a clear improvement on the existing installations.

The dredging tool will be further described with the aid of the following figures.

Figure 1 shows a side view of a possible embodiment of the dredging tool according to the invention with two rows of drag heads (1,2). The drag heads can optionally be provided with teeth. The individual drag heads (1a, 2b) of rows of drag heads (1,2) are each connected to a separate truss structure (3a, 3b) by means of a resilient structure which is shown in more detail in Figures 5a and 5b. The truss structure (3a) is positioned vertically above the first row (1) of drag heads and truss structure (3b) is positioned vertically above the second row (2) of drag heads. The shape of the drag heads (1a) shows that the drag direction of the first row (1) is away from the viewer and that the drag direction of the second row (2) of drag heads (2b) is opposite and towards the viewer focused. The drag heads (1a, 2b) are connected to a suction pipe (4a, 4b) for discharging the soil / water mixture excavated by the drag heads (1a, 2b). The truss constructions (3a, 3b) are individually and resiliently connected to a box-shaped bridge (5). The box-shaped bridge (5) is positioned vertically above the truss constructions (3a, 3b) and connected by columns (6a, 6b) and hydraulic cylinders (7a, 7b).

The hydraulic cylinders (7a) and the columns (6a) connected thereto allow vertical displacement of the truss structure (3a). In Figure 1, three sets of cylinders (7a) and columns (6a) are shown. To this end, the columns (6a) are connected at the bottom to the framework structure (3a) and the columns (6a) are vertically displaceable relative to the box-shaped bridge (5) by guiding them through openings (8a) in the bridge (5) . The hydraulic cylinders (7a) are hereby fixed to the bridge (5). The upper end of the column (6a) is connected by means of a spring construction (10a) to the upper ends of the hydraulic cylinders (7a). Spring construction (10a) is advantageous for absorbing any impact load on the drag heads. Spring structure (10a) is shown in detail in Figure 1a and includes a top plate (11a) connected to the top end of column (6a) and two springs (12a) which are connected to the top ends of hydraulic cylinders (7a). Hydraulic cylinders (7a) are connected on their underside to the box-shaped bridge (5). By means of the hydraulic cylinders (7a), the first row of drag heads (1) and the truss structure (3a) connected thereto can be moved vertically with respect to the second row of drag heads (2) and the truss structure (3b) connected thereto. Half-timbered structure (3b) is connected in the same way to bridge (5) by means of three sets of cylinders (7b) and columns (6b). The stroke length of the hydraulic cylinders (7a, 7b) is chosen such that the desired vertical displacement of the first row of drag heads (1) relative to the bridge (5) is possible.

Figure 1 shows two suction pipes (4a) and two suction pipes (4b). The suction tube (4a) branches so that each branch (36) is connected to a drag head (1a) of the first row of towing purchases (1) and suction tube (4b) branches so that each branch is connected to a drag head (2b) of the second row of tow purchases (2). The suction tube (4a, 4b) is variable in length so that it can absorb the vertical displacement of the truss constructions as described above and also the vertical impact load which is passed on to the suction tube by the drag heads. This is possible by providing suction tubes (4) with two parts that can be slid into each other, resulting in the suction tubes having a varying length. The vertical impact load on the drag heads is initially absorbed by the springs (45 in Figure 5b) through the retractable tubes (37) and then by the stiffer springs (12a, 12b).

The construction as shown in Figure 1 has the advantage that transverse forces and bending moments initiated by the ground reaction forces on the drag heads (1a, 2b) are passed through via the truss structure (3a, 3b) and the vertical columns (6a, 6b attached thereto) ) to the bridge (5) which has a box construction here. Because the bending stiffness of the columns (6a, 6b) is much greater than the bending stiffness of the hydraulic cylinder rods (7a, 7b), the transverse forces and moments will be absorbed almost entirely by the columns (6a, 6b).

Figure 2 shows the bridge construction of Figure 1 where the towing direction of the two rows of towing heads is the same. Figure 2 also shows a sinkable and rectangular frame (15). Framework (15) is formed by two framework beams (16,17) positioned parallel and in the longitudinal direction and two cross beams (18,19). The bridge (5) is movably connected to the framework (15) by means of a bridge part (22) which comprises two guide tubes (20, 21) and a partially shielded space (23) in which the rows of drag heads (1) and the framework construction are vertically ( 3) can move. The bridge part (22) is connected to the two cross beams (18, 19) by means of winch cables (23), which winch cables make a horizontal movement of the bridge part (22) and thus the bridge (5) along the two parallel positioned framework beams (16, 17). For this purpose, frame beams (16, 17) run through guide tubes (20, 21) as described in more detail in Figures 7 and 8. With four hydraulic cylinders (5b), the bridge (5) can be moved vertically upwards relative to bridge part (22) . In this way the digging wheels can be moved upwards, for example to perform maintenance.

Figure 2 also shows that the four corner points (24-27) of the framework (15) are provided with screw anchors (33a) in order to be able to anchor the framework (15) with the water bottom. Each corner point (24, 25, 26, 27) is also provided with a carriage (33) as support means and thrusters (28) which can help move the framework (15). Screw anchor (33a) is driven by a motor (not shown) and is connected to framework (15) by a column (29). Column (29) is connected at its upper end to hydraulic cylinders (30) via a plate (31). Column (29) runs movably through an opening (32) in corner point (24). Hydraulic cylinders (30) are connected at their bottom to corner point (24).

Figure 3 shows the dredging tool of Figure 2 viewed from the bottom up. The numbers refer to the same parts as in Figure 2. The two rows (1) consist of 9 drag heads per row. The two rows (1) are arranged next to each other with the drag heads positioned offset in relation to the drag heads in the other row. In other words, the rows (1) run parallel and are positioned next to each other. In this way, in use, a continuous surface of the water bottom is dug off in case the bridge (5) and bridge part (22) connected thereto are winched (23) from a position close to crossbar (18) towards crossbar (19) (or vice versa) is moved.

Figure 4 shows the bridge (5) of Figure 2. The numbers refer to the same parts as in Figure 2. Figure 4 shows two horizontally extendable excavating means (36a) on the top of truss construction (3) that can be moved outwards and inwards by means of hydraulic cylinders (36b) so that a plane descending to make a stable slope.

The water-bottom mixture of water and solid which is discharged via the branched suction line network (36) via the enveloping suction line (4) by means of the suction pipe (37a) can be transported directly via a line to the water surface to be collected there, for example in a vessel . The water bottom mixture can also be transported to a storage tank that is located on the water bottom. The water bottom mixture thus stored can then be transported from this tank or possibly in this tank to the water surface.

Figure 5a shows how drag head (38) is resiliently connected to truss structure (3a) and to the suction line (36) included therein. Figure 5b is a sectional view AA of Figure 5a. Because each drag head (38) of a row of drag heads is resiliently connected to the joint truss structure (3a), it is possible that the drag heads (38) can move independently of each other in a vertical direction relative to the truss structure (3a). Figure 5b shows a section AA of the drag head (38). In suction line (36) a suction pipe line part (37) with a smaller diameter is present which extends to the drag head (38). The towing direction of towing head (38) is shown with arrow (39), also a horizontal axis.

The drag head (38) comprises a visor (40) rotatably connected to a suction nozzle (42) about a horizontal axis (38a). The visor (40) and suction nozzle (42) are connected to the truss structure (3a) by means of a rotating connection (41). The rotary joint (41) allows a rotation about an axis extending in the towing direction (39) relative to the framework. Furthermore, an intermediate part (41a) can be seen which connects the rotary connection (41) to the truss structure (3a). This intermediate part (41a) will transmit the forces on the drag head to the truss structure. Suction tube (37) is also connected to the rotary connection (41), such that the visor (40) and suction nozzle (42) can rotate with respect to suction tube (37).

Intermediate part (41a) in this case are four columns which are connected at an angle at their upper end to four columns (43) which extend vertically upwards. The columns (43) move movably through a tubular opening (44) of the truss structure (3a). Above and below the tubular opening (44) the column (43) is provided with springs (45) clamped between flanges (46). By removing the upper flanges (46) which are located above the truss structure (3), the drag head (38), suction pipe line part (37), rotating connection (41), intermediate part (41a) and columns (43) can be easily dismantled for example, to be replaced by the same drag head or to be repaired. Suction pipe section (37) can move vertically in the opening of suction pipe (36).

Figures 5a and 5b also show hydraulic cylinders (47) which, depending on the shape of the water bottom, can position the visor (40) in a favorable position of rotation relative to suction nozzle (42).

The rotary connection (41) preferably comprises two portions as shown in Figure 6, one of the portions (50) being connected to the visor (40) and suction nozzle (42) and the other portion (51) being connected to intermediate part (41a). Both parts (50.51) are provided with an opening (52) for passage of the soil / water mixture. Part (50) comprises a circular part provided with recesses (53) and tilting (55). Part (51) also includes a circular part provided with recesses (54) and tilt (56) such that when part (50) and part (51) are joined together to form the rotary connection (41), the tilt (55) of part (50) ) fit into the recesses (54) of part (51) and the tilt (56) of part (51) fit into the recesses (53) of part (50). In this circular space, between tilting (55) and tilting (56), shock-absorbing means are placed in the tangential direction for receiving the torque. In Figure 6, those are preferred springs (57).

Figure 7a shows a guide sleeve (20) of bridge part (22) through which frame toolbar (16) runs as shown in Figure 2. In the figure, frame toolbar (16) is drawn slightly withdrawn so that the inside of the guide tube (20) can be seen . The inside of the guide tube (20) are provided with resilient wheel sets (60, 64) which allows a displacement of the bridge part (22) along the frame toolbar (16) in the longitudinal direction. The wheel sets (60, 64) are designed such that, in use, it also permits 6 kinematic degrees of freedom of the guide sleeve (20) in radial, tangential and rotation (about the vertical axis) direction relative to the frame toolbar (16) . Such freedom of movement of the guide sleeve (20) relative to the framework beam (16) is important and prevents clamping forces when the bridge part (22) is moved by the winches (23) along the framework beams. The frame toolbar (16) is made up of three tubes (61) positioned in parallel which form a triangular section and together form a rigid whole. The outside of these combined tubes (61) is provided with a flat plate (62) provided with a rail (59) on which the wheel sets (60) can engage. The three tubes (61) and the flat plate (62) together form a triangle-like section of the frame toolbar (16).

Figure 7b shows a cross-section of the frame toolbar (16) and the guide sleeve (20), in which the interaction can be seen in more detail between the guide tracks / rails (59) distributed proportionally over the circumference of the frame toolbar (16) and the spring wheel sets (60.64). The flat plates on which the point load of the guide wheels is exerted can be reinforced by the use of radial plate elements (59a) or fitting and fixed tubes (59b) within the cavities of the peripheral frame toolbar (16) and combined tubes (61).

Figure 7c shows a cross-section of the frame toolbar (16) and the guide sleeve (20). The spring wheel sets are now spring rollers (69a) which are spring-mounted on a wheel set as further illustrated in Figure 8C.

Figure 8a shows wheel sets (60) of Figure 7 in more detail. The wheel set (60) is provided with a U-shaped base plate (62). Base plate (62) is fixed on its underside to the inside of guide sleeve (20) such that the upright ends of the U-shaped base plate point to the inside of the guide sleeve (20. Between the upright ends of the U-shaped base plate ( 62) is a four-wheel system (63) resiliently clamped by means of springs (65) On four-wheel system (63) again forms the basis of a wheel set (64) which wheel (67) is perpendicular to the direction of the wheels of the four-wheel The wheel set (64), in which wheel (67) is received, is fixed to the stationary shafts (66) of the four-wheel system (63) and is fixed by the vertical springs (65a) of the wheel set (64). ) capable of accommodating a movement in radial direction The wheel (67) of wheel set (64) engages fixed tracks or rails (59) fixed on the outside of the framework beam (16) as shown in Figure 7a and provides use for a transit in the x 'direction Four-wheel system on which wheel set (64) is positioned, wheel set (64) can make a small displacement in a substantially tangential direction (y 'direction in Figure 8) relative to the inside of the guide sleeve (20) on which wheel set (60, 64) is located. mounted.

Figure 8b shows in detail how the wheel set (64) of Figure 8a can undergo angular rotation ψ, whereby the forces on the wheels (67) and articulation tracks / rails (59) of the frame toolbar (16) are greatly reduced.

Figure 8c shows a roller (69a) which is resiliently connected by means of springs (65a) to two wheel sets (60) as discussed in Figure 8a.

Figure 9 shows schematically how the ends of the frame members (16, 17) and the ends of the cross members (18, 19) are resiliently connected to a corner point in each of the four corners (24, 25, 26, 27) ) of the rectangular frame (15). The slides (33) are resilient (73) connected to the corner points (24, 25, 26, 27) so that when the rectangular frame (15) is anchored in the water bottom, the rectangular framework (15) has a resilient geometry with 6 kinematic degrees of freedom . The resilient connection of the framework beams and the cross beams to the corner points is by means of a ball joint (70), a coupling piece (71) and a spring (72). The ball hinges (70) hereby allow limited angle turns (φ2, Θ2, ψ2) of the framework beams (16,17) and cross beams (18,19) relative to the corner points (24,25,26,27). The displacements of the angular points (24, 25, 26, 27) in the horizontal xy plane are made possible by the expression or expression of spring elements (72) and the angular rotations of the ball joints (70). In order to enable the carriages (33) to properly follow the contours of the water bottom, the carriages are assigned kinematic degrees of freedom (x, y, z, φ, θ, ψ) which are achieved by means of spring (73), hydraulic cylinder ( 74), ball joints (70) and the springs (72) of the angular points (24,25,26,27). Due to the kinematic degrees of freedom (x, y, z φ, θ, ψ) of the slides (33), the slides are enabled to follow the contours of the water bottom when horizontal movements of the framework (15) are made. Moreover, the moments at the corner points (24, 25, 26, 27) will be greatly reduced by the flexibility of the framework (15). The displacements (Y7, Z7) and angular displacements (φ7, Θ7, ψ7) of the bridge part (22) are realized by the translating and rotating spring wheel sets (60,64) shown in Figure 7 and a longitudinal displacement (X7) due to the winches (23). Applicant has found that when such a framework (15) is anchored in the water bottom, a very rigid and form-retaining framework is obtained which allows an undisturbed displacement of bridge part (22) along the framework beams (16, 17).

Figure 10-13 shows a possible version of a bridge. In order to achieve a greater vertical displacement of the rows of drag heads (34, 35) relative to the framework (15), these rows of drag heads (34, 35), the truss structure (3) and the box structure (5) are part of a telescopic construction. Figure 10 shows this construction in which the rows of drag heads (34, 35) are fully pulled up by means of winch cables (80), hydraulic cylinders (81) and hydraulic cylinders (82) and hydraulic cylinders (7). Winch cables (80) can move the truss structure (3) and the rows of excavation means (34,35) connected thereto in vertical direction relative to a bridge part (84). The winches (80) also ensure rotational stability of the truss structure (3) about the width axis of the bridge. Bridge part (84) is a modified bridge part (22) and is also provided with guide sleeves (not shown) for moving along the frame beams. Bridge part (84) is provided with hydraulic cylinders (81) which can cause an open box-shaped structure (85) to move vertically. For this purpose box structure (5) is provided with four upright walls (86) which are provided with resilient guide wheels (87) for guiding the inner wall of the open box structure (85). The inner walls (88) of the rectangular opening in bridge part (84) are also provided with resilient guide wheels (89) for guiding the outer wall of the open box construction (85). Box construction (85) is open at its top and bottom end.

In Figure 11, the half-open box structure (85) is moved downwards by retracting hydraulic cylinders (81).

In Figure 12, the box structure (5) is moved downwardly by extending hydraulic cylinders (82).

In Figure 13, the truss structure (3) and the rows (34,35) of excavation means connected thereto are moved downwards by retracting hydraulic cylinders (7).

Such a bridge which is shown in Figures 10-13 can form part of a sinkable framework (15) as a movable bridge part. The framework beams and the cross beams can be filled with air in order to move the framework (15) from the water bottom to the water surface. Any deviations in the use of gas which could disturb the balance and cause the framework to tilt can be corrected by making use of the thrusters present.

Figure 14a-d shows a dredging tool according to the invention in which the bridge (5) is resiliently connected to a floating vessel (90) by means of four top-mounted hydraulic cylinders (91) which extend from the floating vessel (90) to extend down to the bridge (5). Figures 14a-b show two rows of drag heads (1,2) with the same drag direction. Figures 14c-d show two rows of drag heads (34.35) with opposite drag direction. The bridge (5) can also be a telescopic bridge according to Figures 10-13. Each of the four hydraulic cylinders (91) are connected to the vessel (90) on their upper side by means of a ball joint (92) and a spring. Connected to the vessel (90) here is through a truss (100) connected to the vessel (90). Ball joints (92) can move via the framework (100) by means of a cylinder (101) parallel to the direction of the row of excavating means. In this way, the direction of cylinder (91) relative to bridge (5) can be kept almost vertical when the floating vessel is swinging due to wave movements. Cylinders (101) and (91) will be adjusted in length in response or anticipation of the movement of the floating vessel such that the excavating means are pressed onto the water bottom with a substantially constant vertical force. The spring on the top of the cylinder (91) preferably has a smaller spring constant than the spring constant of the hydraulic cylinder. Due to this construction, there is complete decoupling between the movements of the floating vessel (90) and bridge (5) while maintaining the necessary vertical pressing force on the drag heads. The other end of the hydraulic cylinders (91) is connected to the bridge (5) via ball joints (93). Cylinders (91) can be used to lift the bridge (5) and the hydraulic cylinders (7a, 7b), columns (6a, 6b) and the two rows of drag heads (1, 2) from the water bottom (102) or be pressed onto the water bottom. With the help of hydraulic cylinders (7a, 7b) one row (1) with drag heads can then be positioned on the water bottom (102) while the other row (2) remains in an elevated position. Water surface (103) is also shown. The figure also shows half-timbered structures (3a, 3b), two rows (1,2) of drag heads, columns (6a, 6b) and hydraulic cylinders (7a, 7b) which have already been discussed earlier. Bridge (5) is provided with four upright walls (104) which are confined along the walls by means of a plurality of springs (107, 109) and roll supports (105, 108) in an opening (106) in the floating vessel (90). from small bridge (5), small pendulum and ram movements of the vessel (90) due to wave movements are absorbed.

Figure 15 shows how a sinkable and rectangular framework (15) of Figure 2 is anchored by means of screw anchors (33a) on water bottom (102) and for example at a large water depth below the water surface (103). In Figure 15a the bridge part (22) is moved from right to left by means of winches (23). The rows (1) of drag heads hereby dig a trench (104). In Figure 15b, the bridge part (22) is its extreme left position, after which the direction is reversed and the bridge part (22) is moved to the right by means of winches (23). It shows how row (2) of drag heads is lowered and row (1) of drag heads is positioned upwards when the bridge moves to the right and vice versa if it moves to the left. A subsequent layer is dug off the water bottom and a deeper trench (104) as shown in Figure 15c is created. The shading in Figure 15 indicates which compartments are filled with water with the light shading in frame toolbar (16) indicating that air is present in the two upper tubes (61) and water in the lower tube (61).

Figure 16 shows how the rectangular framework (15) of Figure 2 can be connected to a floating vessel (110) through a framework (111) and 4 cylinders (112). The four cylinders are connected to the corner points (24, 25, 26, 27) and to the framework (111) in the same manner as shown in Figures 14a and 14b. The anchors and supporting means are shown in the figure. It will be clear that they have no function in this embodiment. However, it is not inconceivable that the framework (15) is used alternately in the embodiment according to Figure 16 and in the embodiment according to Figure 15. By disconnecting cylinders (112) at the corner points (24, 25, 26, 27) it can Simply sink the framework and be positioned underneath the floating vessel (110).

Figure 16 also shows two floating loading buckets (114) in which the excavated soil can be collected. Pipes (113) transport the excavated soil to these bins. Figure 16a shows in detail that the upper end of cylinder (112) is connected to framework (111).

Figure 17b shows how a drag head is rotatably connected about the axis in the transverse direction to the truss structure (3). For this purpose, the truss structure (3) consists of a rigid section (3a) and a rotatable section (3b). Rotatable section (3b) is in turn connected to the drag head as also shown in Figure (5a). The rotating shaft (141) is provided with rigid torsion springs (140).

Figure 17a shows how a drag head is cardanically connected to truss construction (3). The drag head is now rotatable about an axis (141) in the transverse direction and rotatable about an axis (143) in the longitudinal direction connected to the truss structure (3). Shafts (141, 143) are provided with rigid torsion springs (140) and (142), respectively, so that the rotatable sections (3b) and (3c) of the truss structure are returned to their horizontal position after, for example, an impact load on the excavator wheel (1) occurred.

Claims (25)

CONCLUSIONS A dredging implement comprising a row of at least 3 drag heads, such that in use the dredging implement is moved over the water bottom in a direction which is perpendicular to the direction of the row of drag heads, wherein the drag heads are connected to a rigid construction which is rigid construction positioned above the row of drag heads and wherein the drag heads are connected to the rigid structure by means of a resilient connection such that a drag head can absorb a vertical load on the drag head independently of another drag head or drag heads, the rigid structure being resiliently connected to a bridge positioned vertically above the rigid structure and wherein the vertical distance between rigid structure and bridge is adjustable, and wherein the bridge is connected by means of a plurality of linear actuators to the rigid structure positioned below such that in use the linear actuators exert an adjustable and vertical pressing force. on the drag heads. A dredging tool as claimed in claim 1, wherein a second row of drag heads and a second rigid structure connected thereto is disposed behind a first row of drag heads and the rigid structure connected thereto and wherein the drag direction of the drag heads of the first row is opposite to the drag direction of the drag heads of the second row and wherein both rows and the rigid structure connected thereto can be moved in vertical direction relative to the other row and the rigid structure connected thereto. A dredging tool according to any one of claims 1-2, wherein the bridge comprises a box construction. A dredging tool as claimed in any one of claims 1 to 3, wherein the bridge is resiliently connected to a floating vessel by means of a plurality of linear actuators which extend downwards from the floating vessel to the bridge and wherein both ends of the linear actuator by means of a ball joint are connected to the floating vessel and the bridge. A dredging tool as claimed in any one of claims 1 to 3, wherein the bridge can move in a longitudinal direction along two frame members positioned parallel and in the longitudinal direction which form a frame with two cross members. A dredging tool as claimed in claim 5, wherein the movable bridge is connected to the two cross members by means of winch cables, which winch cables enable longitudinal movement of the movable bridge along the two parallel positioned framework beams. A dredging tool according to any one of claims 5-6, wherein the movable bridge comprises a guide sleeve at each of its ends, one of the two parallel-positioned frame beams running through the opening of each of the sleeves so that the movable bridge extends into the longitudinal can move towards the frame beams. A dredging tool according to claim 7, wherein the guide sleeves are provided on its inside with resilient wheel sets and / or resilient rollers which in use can give the framework beams 6 kinematic degrees of freedom with respect to the guide sleeve. A dredging tool according to any one of claims 5-8, wherein the corner points of the framework are provided with means for being able to anchor the rectangular frame with the water bottom, and / or wherein the corner points of the rectangular frame are provided with a supporting means. A dredging tool according to any one of claims 5-9, wherein it is resiliently connected to the ends of the frame beams and the ends of the crossbeams and connected to a ball joint with a corner point in each of the four corners of the rectangular frame and wherein the means for being able to anchor the rectangular frame are resiliently connected to the corner points and wherein the optional support means are resiliently connected to the corner points so that when the rectangular frame is anchored to the ground, the rectangular frame has a resilient geometry with 6 kinematic degrees of freedom. A dredging tool according to any of claims 5-10, wherein it can be sunk to a water bottom, can rise from a water bottom to the water surface and can float on the water surface. A dredging tool according to any of claims 10-11, wherein the framework comprises beams, cross beams, the corner points and / or the movable bridge compartments which can be filled with gas and / or water in order to allow the dredging tool to float, to sink to a water bottom or to rise from a water bottom. A dredging tool as claimed in any one of claims 1 to 12, wherein a row of drag heads comprises 3 to 30 drag heads. A dredging tool according to any one of claims 1-13, wherein the drag heads are rotatably connected to the rigid structure about an axis in transverse direction and / or about an axis in longitudinal direction. A dredging tool according to any one of claims 1-14, wherein the drag head comprises a visor which is rotatably connected about a horizontal axis to a suction nozzle which in turn is resiliently connected directly or via one or more intermediate parts to the rigid construction and wherein visor and suction nozzle together form a suction opening for a ground-water mixture of the drag head. A dredging tool as claimed in claim 15, wherein the visor and suction nozzle is connected directly or via one or more intermediate parts by means of a rotating connection to the rigid construction such that visor and suction nozzle can rotate about an axis extending in the towing direction relative to the towing direction. framework or the optional intermediate parts. A dredging tool according to claim 16, wherein the rotary connection is provided with springs in the tangential direction. A dredging tool according to any one of claims 1-17, wherein the drag heads are provided with a suction tube of a variable length, which suction tube is connected to a suction pump by means of a fluid connection. A dredging tool according to any one of claims 1-18, wherein the drag heads are provided with water jets. A dredging tool according to any one of claims 1-19, wherein the drag heads are provided with digging teeth. A dredging tool according to any one of claims 1 to 20, wherein the drag heads are connected to the rigid structure individually or in a group of drag heads. A dredging tool according to claim 21, wherein the drag heads are connected to the rigid structure by means of a resilient connection such that a drag head can absorb a vertical load on the drag head independently of the other drag heads or that a group of drag heads can be connected to the rigid rigid construction is connected such that a group of drag heads can absorb a vertical load on the group of drag heads independently of the other groups of drag heads. A drag head comprising a visor which is rotatably connected about a horizontal axis to a suction nozzle wherein visor and suction nozzle together form a suction opening for a ground-water mixture of the drag head and wherein the suction nozzle is connected via a rotary connection to a suction tube such that visor and suction nozzle can rotate about an axis extending in the drag direction of the drag head and wherein the rotary connection is provided with shock-absorbing means in the tangential direction of the rotary connection. A trailing head as claimed in claim 23, wherein the rotary connection comprises two parts, a first part being connected to the visor and suction nozzle and a second part being connected to the suction pipe and both parts being provided with an opening for passage of the ground / water mixture which is drawn in use by the drag head and wherein the first part comprises a circular part which is provided with recesses and tilting and the second part comprises a circular part which is provided with recesses and tilting such that when the first part and the second part are assembled until the rotary joint the tilting of the first part fits into the recesses of the second part and the tilting of the second part fits into the recesses of the first part and wherein in this circular space the shock-absorbing means are present between tilting the first part and the tilt of the second part. A trailing head according to any one of claims 23-24, wherein the shock-absorbing means are springs. -N O ω 33a μ —4 05 O> n5 o 3/20