Device for removing dredging material, and method for operation thereof

Abstract: A device for removing dredging material from a water bed, comprising a rotatable cutting head (2) for cutting away the dredging material, and also conveyance means (4) for discharging the dredging material cut away, which conveyance means comprise a pump (5) which is connected to a pressure line. For complete removal of the dredging material cut away, the suction side of the pump is connected to a bucket (1), in which bucket the cutting head is situated. The suction connection of the pump also opens into the bucket.

Description: The invention relates to a device for removing dredging material from a water bed, comprising a rotatable cutting head, accomodated in a housing, for cutting away the dredging material, which housing is connected to a pump for discharging the dredging material cut away. Such a device is known from JP-A-2243829. It comprises a housing with a cutting head at the bottom end face, and also a pump which sucks up and pumps out the material cut away. In view of the compact dimensions of the known device, it is easy to use at locations where little or no space is available. An example given is use in construction pits into which foundation piles have already been driven. After the piles have been inserted, the top layer still has to be removed, for which purpose the abovementioned device is used, since it can be placed between the piles. However, the known device has the disadvantage that manoeuvring with it is not easy. This gives rise to the risk that it will knock against the piles, thereby causing damage. In addition, the cutting head spreads part of the material cut away through the water in the construction pit, which is a disadvantage if underwater concrete has to be poured. The object of the invention is therefore to provide a device of the type described in the preamble which does not have these disadvantages. That is achieved through the fact that the housing is a bucket and said bucket has at least one straight wall. The material cut away is pressed directly into the bucket by the cutting head, with the result that it has hardly any chance of spreading through the water. In addition, the material is extracted directly from the enclosed space into the inside of the bucket, with the result that the risk of spreading is further reduced. The bottom right wall bears a cutting edge, and in operation forms the bottom boundary of the bucket. This means that the material to be removed can be cut away in such a way that a flat surface is produced. The cutting edge is preferably a greater distance from the bottom than the other walls of the bucket. The wall with cutting edge designed in this way projects relative to the other walls. In operation, it acts as a support for the bucket, as a result of which the cutting head itself does not have to rest on the material to be removed, and a uniformly worked bottom surface is obtained. The bucket can be designed in all kinds of ways. According to a first variant, the bucket can have a square or rectangular bottom, surrounded by four walls. According to a second variant, the bucket can have a trapezoidal bottom; further variants, for example with curved walls, are also conceivable. It is also possible, for example, for two cutting heads to be accommodated next to each other in the bucket. In a variant in which, for example, in operation the wall at the shortest parallel trapezoidal side forms the bottom boundary of the bucket, two of such cutting heads can be provided. This variant can be used, for example, for excavating or cleaning ditches and the like. The upright walls, in the case of a trapezoidal bucket the slanting walls, can in this case also have a cutting edge. The cutting head preferably has at least two blades, which are disposed essentially helically, while each blade can bear at least one cutting tooth on its front side, viewed in the direction of rotation. According to a particularly advantageous embodiment, the bucket has a base which at one side has a casing projecting relative to the base, and the centre line of the cutting head runs crosswise to the base. The bucket can have an essentially square or rectangular base, in which case the casing consists of four panels, one of which is designed with a cutting edge. The bucket can be forced with the cutting edge into the dredging material, so that an accurately determined and flat bottom surface remains. Due to the fact that the cutting head projects partially beyond the casing, it can easily reach the dredging material. The cutting head digs in as a result of the helical arrangement of the cutting blades, and in the process pulls the cutting edge and the remainder of the bucket firmly against the dredging material to be removed. The advantage thereof is that during manoeuvring of the device it can be held in the correct position with limited external forces. The result is that the device can be positioned accurately, which means that the risk of collisions with other objects, for example foundation piles, is considerably reduced. Good results are obtained if the suction connection of the pump opens into the base of the bucket; an embodiment in which the suction connection is situated in the part of the base near the panel designed with cutting edge is also advantageous for full removal of the material cut away. The rear side of the cutters is situated directly in front of the suction mouth, so that the latter is constantly being wiped clean, and clogging is virtually ruled out. Fixed cutters can also be provided on the bottom of the bucket directly opposite the rotating cutters. Such an arrangement of the cutters ensures that sticky clay does not clog the bucket. According to a preferred embodiment, the pump is accommodated in a housing, while the outside of the base of the bucket faces the housing, and the panel with the cutting edge faces away from the housing. Such an embodiment is suitable in particular for fitting on the articulated arm of a hydraulic crane; for this purpose, at one of its end faces the housing has coupling means for fixing to a crane arm. In this case the suction side of the pump is fitted centrally in the other end face of the housing, and is connected to the bucket by way of an elbow. In a preferred embodiment both the bucket and the elbow are connectable at different positions in the peripheral direction of the housing to said housing and the suction side of the pump respectively. For this purpose, the housing can have a cylindrical shell, and the bucket can bear a correspondingly curved fixing flange which is fixed to the housing. In the case of this embodiment the device, depending on the position of the bucket, can operate in different directions relative to the hydraulic crane, such as towards said crane, sideways, or away from said crane. Sensor means can also be provided for measuring the angular position of the bucket relative to the horizontal. With the aid of said sensor means, the correct position of the device can be maintained during the dredging, even when the device is under water. The invention also relates to a method for operating the device described above, comprising fitting the bucket with its open side facing the surface or the front of the dredging material to be removed, setting in rotation the cutting head for cutting away the dredging material, and sucking up the dredging material cut away out of the bucket. At the commencement of the work, the bucket of the device is placed with its open side facing downward on the material to be dredged away. The cutting head then digs in, and the device is manoeuvred in such a way that it tilts through 90 degrees, in which case the opening of the bucket is then directed sideways. In that position a trench is then dredged. If in the direction of advance the panel with cutting edge is held at an angle of minus five degrees relative to the horizontal, the device can be prevented from slowly creeping upwards as the trench progresses. The invention will be explained in greater detail below with reference to an exemplary embodiment shown in the figures. Figure 1 shows a view in perspective of the device according to the invention. Figure 2 shows a side view of the device according to Figure 1. Figure 3 shows the device fitted on the arm of a hydraulic crane, in the initial position. Figure 4 shows the device in the dug-in position. Figure 5 shows an alternative embodiment. The device shown in Figure 1 for removing dredging material comprises a bucket, indicated in its entirety by 1, in which a cutting head 2 is rotatably suspended. The bucket 1 is fixed by means of support 3 to the cylindrical housing 4, in which a pump unit 5 is situated. Fitted at the top side of the housing 4 are suspension eyes 6, which can be gripped by a correspondingly designed coupling piece on a hydraulic crane arm. Eyes 7 are also provided, for the purpose of lifting the device with cables. At the bottom side of the housing 4 runs a suction pipe 8, which at one side is connected to the pump 5 and at the other side opens by way of hole 9 in the bottom 10 into bucket 1. The bucket 1 also has a bottom wall 27, provided at the front side with a cutting edge 11. In addition, the bucket 1 has a top wall 26, which is shorter than the bottom wall 27, and has two side walls 12 running between them. The cutting head 2 in the exemplary embodiment shown has three blades 13, running helically and each provided with 2 cutting teeth 14. The cutting head 2 also has a centring element 15. The cutting head 2 is mounted on a hydraulic motor with reduction gearbox 16, which is driven by hydraulic lines which otherwise are not shown. The bucket is also provided with four nozzles 17, which are supplied by pressure lines 18. At its end facing the pump 5 the L-shaped suction pipe is provided with a flange 19, while the supporting means bear a fixing flange 20 which is curved in a manner corresponding to the cylinder 4. The two flanges 19, 20 and the supports 21 are fixed by means of bolts to the cylindrical housing 4. The position of bucket 1 and suction line 8 in this case can be varied along the periphery of the cylindrical housing 4 through the fact that fixing holes 22 for flange 20 are provided at regular intervals. The flange 19 and the supports 21 can also be fixed at corresponding points. The advantage of this design is that the bucket 1 with the cutting head 2 can face either towards or away from the hydraulic crane. It is also possible to fit bucket 1 and cutting head 2 directed sideways on the cylindrical housing 4. For operation of the device according to the invention, it is coupled first of all to the arm of a hydraulic crane. The device is then rotated in such a way that the cylindrical housing 4 lies horizontally, and the bucket 2 has its opening facing the surface to be worked: see Figure 3. The device in this case is suspended from the coupling piece 23, which is situated on the end of the arm 25 of a hydraulic crane. The cutting head 2 and the pump 5 are then put into operation, and the dredging material is removed, and the situation shown in Figure 3 is ultimately obtained. The device in this case is tilted through 90°; the dredging can then be continued in the position of the device shown in Figure 4, in which the device in its entirety is moved in the same position to the right in Figure 4 and makes a trench in the process. The embodiment shown in Figure 5 has a trapezoidal bottom 30, surrounded by bottom wall 31 and side walls 32, all provided with a cutting edge, and top wall 33. Two cutting heads 34 are accommodated in the bucket. Nozzles 35 are also provided. A ditch, for example, can be excavated with such a device.

Claims: Device for removing dredging material from a water bed, comprising a rotatable cutting head (2), accommodated in a housing (1), for cutting away the dredging material, which housing is connected to a pump (5) for discharging the dredging material cut away, characterized in that the housing is a bucket and said bucket has at least one straight wall. Device according to Claim 1, in which the straight wall (27) bears a cutting edge (11), and in operation forms the bottom boundary of the bucket. Device according to Claim 2, in which the cutting edge (11) is a greater distance from the bottom (10) than the other walls of the bucket. Device according to Claim 1, 2 or 3, in which the centre line of the cutting head runs crosswise to the bottom (10) of the bucket. Device according to Claim 4, in which the bucket has an essentially square or rectangular bottom (10). Device according to Claim 1, 2 or 3, in which the bucket has a trapezoidal bottom (10). Device according to Claim 6, in which in operation the wall at the shortest parallel trapezoidal side forms the bottom (10) boundary of the bucket. Device according to one of Claims 1 - 7, in which the cutting head (2) has at least two blades (13), which are disposed essentially helically. Device according to Claim 8, in which each blade (13) bears at least one cutting tooth (14) on its front side, viewed in the direction of rotation. Device according to one of the preceding claims, in which the cutting head (2) projects partially beyond the walls of the bucket (1). Device according to one of the preceding claims in which the suction connection of the pump (5) opens into the bottom (10) of the bucket (1). Device according to Claim 11, in which the suction connection (9) is situated in the part of the bottom near the wall designed with cutting edge (11). Device according to Claim 12, in which the pump (5) is accommodated in a housing (4), the outside of the bottom of the bucket faces the housing, and the wall with the cutting edge (11) faces away from the housing. Device according to Claim 13, in which the suction side of the pump (5) is fitted centrally in an end face of the housing (4), and is connected to the bucket (1) by way of an elbow (8). Device according to Claim 14, in which both the bucket (1) and the elbow (8) are connectable at different positions in the peripheral direction of the housing to said housing (4) and the suction side of the pump (5) respectively. Device according to Claim 15, in which the housing (4) has a cylindrical shell, and the bucket bears a correspondingly curved fixing flange which is fixed to the housing. Device according to Claim 14, 15 or 16, in which at the other end face the housing bears means (6) for fixing to a crane arm. Device according to Claim 13, 14, 15, 16 or 17, in which sensor means are provided for measuring the angular position of the bucket (1) relative to the horizontal, and/or the height position of the bucket. Method for operating a device according to one of the preceding claims, comprising fitting the bucket (1) with its open side facing the surface or the front of the dredging material to be removed, setting in rotation the cutting head (2) for cutting away the dredging material, and sucking up the dredging material cut away out of the bucket. Method according to Claim 19 for operating the device according to one of Claims 13 - 18, comprising placing the bucket (1) in such a way that the cutting edge (11) is situated below the cutting head. Method according to Claim 20, in which the bucket with cutting edge (11) is held against a front of dredging material, and partly through the helical movement of the cutting head (2) is advanced while simultaneously cutting away said dredging material. Method according to Claim 21, in which in the direction of advance the panel with cutting edge (11) is held at an angle of minus five degrees relative to the horizontal.

Inventors: BOL LIJZIA, BOL, LIJZIA
Applicants: BALLAST NEDAM BAGGEREN BV, BALLAST NEDAM BAGGEREN B.V.
Application year: 1995
Main classification: E02F3
IPC codes: E02F3