WO2014015393A1

WO2014015393A1 - Replaceable dredging tooth and cutter head provided with at least one such replaceable dredging tooth.

Info

Publication number: WO2014015393A1
Application number: PCT/BE2012/000037
Authority: WO
Inventors: Peter VANHEVEL
Original assignee: Ondernemingen Jan De Nul, Naamloze Vennootschap
Priority date: 2012-07-26
Filing date: 2012-07-26
Publication date: 2014-01-30
Also published as: EP2877641A1

Abstract

Replaceable dredging tooth (17) comprising at least a tooth body (28); a central passage (31) extending axially through the tooth body (28); tooth body connection means (35) for releasably connecting the dredging tooth body (28) to a cutter head (8); a releasable tooth point (37); and, tooth point locking means (40) for locking and unlocking the dredging tooth point (37) with respect to the tooth body (28) which are operable from the backside (41) of the tooth body (28) at the tooth body base (30), when the dredging tooth (17) is released from the cutter head (8), at least for releasing the tooth point (37) from the tooth body (28).

Description

Replaceable dredging tooth and cutter head provided with at least one such replaceable dredging tooth.

The present invention relates to a replaceable dredging tooth suitable for being mounted on a cutter head of a cutter suction dredger.

As is known in the domain of dredging, cutter heads of cutter suction dredgers are intended for loosening underwater soil or bedrock when rotated in a working direction and for sucking the loosened material into a barge or vessel by means of a pump or to pump the material to an onshore dumping place and so on.

The cutter head is provided at one extremity of a cutter ladder which is supported in a rotatable manner in two trunnions at its other extremity in the cutter suction dredger for an downwards and upwards movement of the cutter head, respectively in order to bring it in contact with the underwater bottom or at the contrary in order to bring the cutter ladder with cutter head again in its stored position. Furthermore, the cutter head is mounted on a rotatable shaft provided in the cutter ladder for a rotation of the cutter head around the axial direction.

On the cutter ladder also a suction tube is provided which is connected to the cutter head for sucking the loosened material. Known cutter heads have been improved considerably and the most recent types form a revolving body rotatable around a central axis, which revolving body comprises a small diameter hub provided at its farthest extremity from the cutter ladder and a larger diameter ring at an axial distance from the hub, the hub and the ring being connected to one another by means of cutter arms. The cutter arms consist essentially of flat blades which are each shaped symmetrically around their central curved plane of mainly helical form.

Each cutter arm has a front edge and a back edge, the front edge of each cutter arm being provided with dredging teeth, which are of course intended for loosening the soil or rock.

Furthermore, the blades which form the cutter arms, are somewhat inclined towards the central axis in such a way that loosened bed rock or soil is directed towards the central axis, when the cutter head rotates in the working direction, so that it can be sucked into the suction tube. It is clear that a good design of a cutter head for a cutter suction dredger requires a compromise between two contradicting needs.

On the one hand, the cutter head must be as robust and wear-resistant as possible and have a very high strength in order to be able to withstand the very high forces and loads which act on the cutter head during dredging for loosening the bottom material.

On the other hand, the structure of the cutter head must be as open as possible and must have a hydrodynamic shape in order to allow an efficient flow of the loosened material through the available spaces between the cutter arms into the suction tube. In order to reduce as much as possible out of service periods needed for reparing or replacing a worn dredging cutter head, which causes inevitably undesired production interruption, the dredging teeth are nowadays of a replaceable type.

In particular, the cutter arms are therefore provided at their front edge with sockets arranged symmetrically with respect to the central plane of the concerned cutter arm, each socket having a central opening in which an adapter is inserted with an insert part.

This insert part has a shape which is complementary to the central opening in the socket. The adapters are also provided with an adapter head extending out of the concerned socket and which has a shape complementary to the hole in an afore-mentioned replaceable dredging tooth. This type of arrangement is very practical in that it allows an efficient replacement of the dredging teeth when the cutter head is in place on the cutter suction dredger and so without any need for dismounting the cutter head itself . Furthermore, the positioning of the sockets is advantageous in that the replaceable dredging teeth do essentially not obstruct the openings between the cutter arms, so that an open and hydrodynamic structure of the cutter head is still ensured.

The standing time of the replaceable dredging teeth can be increased by using dredging teeth with as much wear mass as possible, which is at present obtained by increasing the length of the replaceable dredging teeth as much as possible.

Obviously, by increasing the dredging teeth length, also the moment forces on the teeth are increased and only a strong adapter with a big base on the cutter arm can withstand the huge moments concerned.

On the other hand, when the size of the adapters is increased, less adapters can be mounted on the front edge of the concerned cutter arm due to lack of sufficient space.

Nevertheless, for a certain size of cutter head, decreasing the number of dredging teeth and accompanying adapters under a certain minimum number would also be no suitable solution, since this would have negative consequences on the achievable production. In other words, with the present technology available the maximum obtainable standing time for the replaceable dredging teeth seems to have been reached by using dredging teeth with their maximum allowable length, corresponding to the space available when a minimum required number of dredging teeth is at least provided on each cutter arm in order to achieve acceptable production rates. It is therefore an objective of this invention to provide an improvement to the existing cutter suction dredging equipment, as well as to provide solutions to possibly not- mentioned problems. In particular, it is an objective of the present invention to provide an improved type of replaceable dredging tooth which has a longer standing time on the cutter head than the known replaceable dredging teeth, while the production achieved is at least as high as with the known dredging teeth, if not higher.

It is another objective of the present invention to keep the structure of the cutter head as open as possible in order to ensure efficient flow of loosened material through the cutter head.

To this end, the present invention relates to a replaceable dredging tooth suitable for being mounted on a cutter head of a cutter suction dredger the replaceable dredging tooth comprising at least:

- a tooth body with a tooth body top and a tooth body base; - a central passage extending axially through the tooth body from the tooth body top to the tooth body base;

- tooth body connection means at the base of the tooth body for releasably connecting the dredging tooth body to a cutter head;

- a releasable tooth point with an elongated tooth point shaft which is provided at one end with a tooth point head, the tooth point head intended for extending outside the tooth body top and the tooth point shaft fitting slidingly into the central passage; and,

- tooth point locking means for locking the tooth point to the tooth body and releasing the tooth point from the tooth body and wherein the tooth point locking means are operable from a backside of the tooth body at the tooth body base, when the dredging tooth is released from the cutter head, at least for releasing the tooth point from the tooth body.

A first advantage of a replaceable dredging tooth according to the present invention is that the replaceable dredging tooth has a tooth body which is essentially of the same shape as the base of an existing dredging tooth, so that existing methods for attaching or releasing the replaceable dredging tooth to or from a cutter arm, which methods have proven their efficiency, are still applicable.

Another advantage of a replaceable dredging tooth according to the present invention is that it is provided with a releasable tooth point, so that tooth points can be inserted which have suitable characteristics corresponding to the soil or rock to be dredged. Still another advantage of a replaceable dredging tooth according to the present invention is related to the characteristic that the tooth point locking means by which the tooth point is locked in the tooth body or by which the tooth point is released from the tooth body are essentially provided inside a central passage in the tooth body, so that a compact arrangement is obtained which does not obstruct in any way the openings between the cutter arms for flow of loosened material.

Another advantage of a replaceable dredging tooth according to the present invention related thereto is that the tooth point locking means are only available when the replaceable dredging tooth is released from the cutter head.

First of all, in that way the tooth point locking means are protected in a space inside the dredging tooth, so that the tooth point locking means are not directly subjected to the forces induced during dredging and are not prone to wear by contact with soil or bedrock and are at least within certain limits prevented from being blocked by loosened material .

Furthermore, this means again that the replaceable dredging tooth according to the invention can easily be removed as a whole from the cutter head for being treated in a workshop, so that no additional mounting time or dismounting time during the dredging operation is required for replacing the dredging tooth.

A preferred embodiment of a replaceable dredging tooth according to the invention has a tooth point which is provided with a hardened and/or wear resistant core.

Even more preferably according to the invention the tooth point has a wear resistant core made of tungsten carbide (WC) .

A big advantage of such a replaceable dredging tooth according to the invention is that the standing time can be kept higher than with the existing replaceable dredging teeth, since the core is more wear resistant.

As a consequence, a known replaceable dredging tooth of a certain length will wear much faster than a replaceable dredging tooth according to the invention with the same length.

On the other hand, it is also possible to obtain a certain standing time for the replaceable dredging tooth according to the invention with a much shorter tooth length than would be the case with a known dredging tooth.

A first reason is of course that a dredging tooth according to the invention with a more rigid and wear resistant core is more capable of withstanding a certain load than the known dredging teeth which are made of a less rigid and less wear resistant material, so that for a dredging tooth according to the invention less wear mass and as a consequence a shorter length is sufficient in order to obtain the same standing times. Another advantage that combines with the aforementioned is that when the dredging tooth length is kept shorter, also the load on the dredging tooth is smaller since the shorter dredging tooth length results in a smaller moment load on the replaceable dredging tooth according to the invention.

This demonstrates that the advantage of a replaceable dredging tooth according to the invention is quite substantial and that the relation between the tooth length, the load on the dredging tooth and the rigidity of the dredging tooth is not straightforward.

From the foregoing, one can also easily understand that with replaceable dredging teeth having a bigger wear resistance, it is possible to find another optimum between the , achievable production volume, the number of replaceable dredging teeth provided at each cutter arm and the standing time of a replaceable dredging tooth on a cutter arm, just by adapting the size of the replaceable dredging teeth.

The present invention also relates to a cutter head provided with at least one replaceable dredging tooth according to the invention as described before. With the intention of better showing the characteristics of the invention, hereafter, as example without any limitative character, a preferred form of embodiment is described of a cutter head in accordance with the invention, as well as replaceable teeth in accordance with the invention, with reference to the accompanying drawings, wherein: figure 1 represents a schematic side view on a cutter suction dredger provided with a cutter head according to the present invention;

figure 2 represents on a bigger scale a perspective view of the cutter head according to the invention indicated by F2 in figure 1;

figure 3 represents on a still larger scale a replaceable dredging tooth according to the invention and a part of the cutter head indicated by F3 in figure 2, the replaceable dredging tooth being represented in a disassembled state;

figures 4 and 5 represent cross-sectional views through the same parts represented in figure 3 in an assembled state, respectively indicated by IV-IV and V-V and,

figure 6 represents on a bigger scale the part of the dredging tooth which is indicated in figure 5 by F6.

Figure 1 represents a typical cutter suction dredger 1 which mainly consists of a vessel 2 provided with spud posts 3 for anchoring the dredger 1 in the underwater ground 4 and with a cutter ladder 5 supported at one end 6 rotatably in the dredger vessel 2 for an upward and downward movement and provided at its other end 7 with a cutter head 8 in accordance with the invention.

The cutter head 8 is mounted on a shaft which is driven for a rotation around its central axis AA' . Seabed soil or rock 4 loosened by the cutter head 8 mixed with water is sucked through a suction tube 9 which is connected at one extremity to the cutter head 8 and at its other end to an inlet of a dredging pump 10 installed on board of the dredger 1. The dredging sludge is discharged through a discharge pipe 11 which is connected at the outlet of the dredging pump 10.

Figure 2 represents a more detailed view of the cutter head 8 according to the invention.

This cutter head 8 is a revolving body intended for rotational movement around its central axis AA' and especially for. a rotational movement in. a working direction BB' for loosening bed rock or soil 4.

The cutter head 8 mainly consists of a ring 12 and a hub 13 at an axial distance C from one another, which are connected to one another by means of cutter arms 1 .

In the embodiment represented in figure 2 the cutter head 8 is provided with six such cutter arms 14.

Each cutter arm 14 is mainly a flat blade 14 which is essentially shaped symmetrically around a central geometrical curved plane HH' .

In the case represented in figure 2 the geometrical curved plane HH' has a helical shape.

Furthermore, each cutter arm 14 has a front edge 15 and a back edge 16.

The front edge 15 of each cutter arm 14 is considered as being the edge 15 which is the first to be in contact with the underwater soil 4 when the cutter head 8 is rotating in the working direction BB' and it is the front edge 15 which is provided with replaceable dredging teeth 17 according to the present invention. The cutter arm blades 14 are somewhat inclined towards the central axis AA' with an angle G, in such a way that loosened bed rock or soil 4 is directed towards the central axis AA' when the cutter head 8 rotates in the working direction BB' .

Each dredging tooth 17 is oriented in an axial direction KK' which is mainly aligned within the above-mentioned central plane HH' of the concerned cutter arm 14 and which is in a direction perpendicular to the front edge 15 at the position of the concerned replaceable dredging tooth 17.

Each cutter arm 14 is furthermore provided with multiple replaceable dredging teeth 17 in accordance with the invention, i.e. in the represented case with eighth such replaceable teeth 17.

The cutter arms 14 are provided at their front edge 15 with sockets 18 arranged symmetrically with respect to the central plane HH' of the concerned cutter arm 14.

As is represented in figure 3, these sockets 18 have a central opening 19 in which an adapter 20 is inserted.

Such an adapter 20 has an insert part 21 with a shape which is more or less complementary to the central opening 19 in the socket 18.

In the represented case, the opening 19 has an essentially cylindrical part 22 and a widened part 23 of conical shape towards the outside of the socket 18.

As a consequence, the insert part 21 has a cylindrical part 24 and a conical part 25, which fit within the corresponding parts 22 and 23 of the socket 18. Each adapter 20 is also provided with an adapter head 26 of, in this case, more or less pyramidal shape, which adapter head 26 is extending out of the concerned socket 18 and which is intended for receiving a replaceable dredging tooth 17 according to the present invention.

In order to fix the adapter 20 to the socket 18 a hole 27 is provided in the socket 18 in which a bolt, pin or the like can be introduced for locking the adapter 20. Such a replaceable dredging tooth 17 is represented in more detail in figures 4 and 5 in the assembled status.

A replaceable dredging tooth 17 according to the invention comprises first of all a tooth body 28 which is mainly shaped as a conical or pyramidal frustrum with a tooth body top 29 having a reduced outside diameter or size U and with a tooth body base 30 having an enlarged outside diameter or size V compared to the outer diameter or size U of the tooth body top 29. The tooth body 28 is furthermore provided with a central passage 31 extending axially through the tooth body 28 from the tooth body top 29 to the tooth body base 30.

In the embodiment represented in the figures, this central passage 31 comprises two different passage portions, i.e. on the one hand, a top passage portion 32 in the tooth body top 29 having a mainly constant and preferably cylindrical cross section and, on the other hand, a base passage portion 33 in the tooth body base 30 in which the opening of the central passage 31 is widened with respect to the opening forming the top passage portion 32.

The cross section of the base passage portion 33 enlarges in a direction from the top passage portion 32 to the tooth body base 30.

The base passage portion 33 has also preferably an essentially non circular cross-section corresponding in this case to the pyramidal shape of the adapter head 26, so to form means for preventing an axial rotation of the dredging tooth 17, when mounted on the cutter head 8.

Of course, according to the invention, it is not excluded to provide the adapter head 26 with another outer shape which is complementary to an inner shape of the base passage portion 33 in the dredging tooth 17. The dredging tooth 17 is furthermore provided at the tooth body base 30, and in particular at one side 34 of the tooth body base 30, with connection means 35, formed mainly by an inward directed lug 35, for connecting the dredging tooth 17 to the adapter head.

With that aim, the adapter head 26 has a recess 36 in which the inward directed lug 35 on the dredging tooth 17 can be introduced or hooked, so that the replaceable dredging tooth 17 can be connected to the adapter 20 by means of a pin, not represented in the figures, inserted between the lug 35 on the dredging tooth 17 and the recess 36 in the adapter head 26.

Very important according to the invention is the characteristic that the dredging tooth 17 comprises furthermore a releasable tooth point 37, with an elongated tooth point shaft 38 which is provided at one end with a tooth point head 39 which is intended for extending outside the tooth body top 29, as is for example demonstrated by means of figure 4 to 6 which represent a dredging tooth 17 in the assembled status. The tooth point shaft 38 fits slidingly into the central passage 31, in particular in the top passage portion 32 of the central passage 31.

Since top passage portion 32 in the tooth body 28 is a cylindrical passage 32, the tooth point shaft 38 is provided with a cylindrical part adjacent to the tooth point head 39 with an outside diameter N corresponding to an inside diameter 0 of the cylindrical top passage portion 32. Preferably, the tooth point shaft 38 has a length L corresponding to the length M of the top passage portion 32 of the tooth body 28.

Additionally, the adapter head 26 is preferably also introduced into the base passage portion 33 of the tooth body 28 until it reaches the top passage part 32, so that the tooth point shaft 38 is touching the adapter head 26 in the assembled status. As an alternative, the length L of the tooth point shaft 38 and the length of the part of the adapter head 26 which is introduced in the base passage portion 33 can be adapted to obtain the similar result, i.e. that the toot point 37 is supported backwards by the adapter head 26.

The dredging tooth 17 furthermore comprises tooth point locking means 40 for locking the tooth point 37 to the tooth body 28 and releasing the tooth point 37 from the tooth body 28.

A very practical characteristic of the invention is that the tooth point locking means 40 are operable from the backside 41 of the dredging tooth body 28 at the tooth body base 30, when the dredging tooth body 28 is released from the cutter head 8 and at least for releasing the tooth point 37 from the tooth body 28. In particular, in the embodiment represented in the figures 3 tot 6, the releasable locking means 40 are formed by the combination of a circular groove 42 in the tooth body 28 by which the inside diameter O of the top passage portion 32 is locally somewhat enlarged; a circular groove 43 in the tooth point shaft 38 by which the outside diameter N of the tooth point shaft 38 is locally somewhat narrowed and a snap ring 44 which can be snapped into the grooves 42 and 43 provided in the tooth body 28 and the tooth point shaft 38 respectively, for locking the tooth point 37 in the tooth body 28.

It is clear that in the embodiment represented in the figures, the tooth point 37 can be locked into the tooth body 28, by providing firstly the snap ring 44 in the groove 43 on the tooth point shaft 38 and by then inserting the tooth point shaft 38 into the top passage portion 32 until the snapring 44 snaps into the groove 42 in the tooth body 28.

In order to release the tooth point 37 from the tooth body 28, the tooth body 28 must be firstly released from the adapter head 26, after which the tooth point 37 can be released from the tooth body 37 by pushing or beating with a hammer and punch on the shaft 24 from the backside 41 of the tooth body 28.

In this way the releasable locking means 40 are completely localised inside the dredging tooth 17 so that they do not disturb in any way the flow during dredging through a cutter head 8 on which the dredging tooth 17 is installed, while an easy mounting and dismounting of the dredging tooth 17 on a cutter arm 14 is still ensured. According to the invention it is interesting when the tooth point locking means 40 are such that they provide in an axial location of the tooth point 37 into the tooth body 28 while allowing a rotation of the tooth point 37 in the top passage portion 32 of the tooth body 28.

In that case, the tooth points 37 of the dredging teeth 17 on the cutter arms 14 of a cutter head 8 are allowed to rotate around their axial direction KK' during dredging, so that the tooth points 37 wear uniformely in all directions.

Of course it is not excluded from the invention to provide tooth point locking means 40 which are of a completely different character of have a completely different shape, than the tooth point locking means illustrated in the figures.

For example, in an embodiment wherein the tooth point shaft 38 extends into the the widened base passage portion 33 of the central passage 31, when the tooth point 37 is mounted on the tooth body 28, the tooth point locking means 40 can also be positioned in this widened base passage portion 33.

In that case, the tooth point locking means 40 may consist for example of a nut with internal thread which can be screwed onto external thread provided on the tooth point shaft 38 and wherein the nut is screwed for example against a supporting face at the transition between the top passage portion 32 and the base passage portion 33.

Other tooth point locking means 40 such as a circlips provided in a groove on the tooth point shaft 38, or tooth point locking means 40 comprising springlike parts, locking pins or bolts and so on are not exlcuded in an y way from the invention. As explained in the introduction, it is of course the intention of the invention to fabricate the tooth point 37 entirely or partly in a very hard and wear resistant material . In the embodiment of a dredging tooth 17 according to the invention the tooth point 37 is provided with a hardened and/or wear resistant core 45.

Preferably this wear resistant core 45 of the tooth point 37 is made of tungsten carbide (WC) .

The tooth point head 39 has preferably also a conical part with a bottom which is in the mounted status- adjacent to the tooth body top 29, the diameter W of this conical part corresponding to the outer diameter U of the tooth body top 29.

In that way the dredging tooth 17 has a smooth outer shape. The present invention is by no means limited to a replaceable dredging tooth 17 and cutter head 8 according to the invention described as an example and illustrated in the drawings, but such a replaceable dredging tooth 17 and cutter head 8 according to the invention can be realised in all kinds of variants, without departing from the scope of the invention.

Claims

Claims .

Replaceable dredging tooth (17) suitable for being mounted on a cutter head (8) of a cutter suction dredger (1), characterized in that the replaceable dredging tooth (17) comprises at least:

- a tooth body (28) mainly shaped as a frustrum with a tooth body top (29) and a tooth body base (30) ;

- a central passage (31) extending axially through the tooth body (28) from the tooth body top (29) to the tooth body base (30) ;

- tooth body connection means (35) at the base of the tooth body (28) for releasably connecting the tooth body (28) to a cutter head (8);

- a releasable tooth point (37) with an elongated tooth point shaft (38) which is provided at one end with a tooth point head (39) , the tooth point head (39) intended for extending outside the tooth body top (29) and the tooth point shaft (38) fitting slidingly into the central passage (31) ; and,

- tooth point locking means (40) for locking the tooth point (37) to the tooth body (28) and releasing the tooth point (37) from the tooth body (28) and wherein the tooth point locking means (40) are operable from a backside (41) of the tooth body (28) at the tooth body base (30), when the dredging tooth (17) is released from the cutter head (8), at least for releasing the tooth point (374) from the tooth body (28) .

Replaceable dredging tooth according to claim 1, characterized in that the tooth point head (39) is forming a pick point or a chisel point of the dredging tooth (17) .

Replaceable dredging tooth according to any of the preceding claims, characterized in that the tooth point (17) is provided with a hardened and/or wear resistant core (45) .

Replaceable dredging tooth according to any of the preceding claims, characterized in that the tooth point (37) has a wear resistant core (45) made of tungsten carbide (WC) .

Replaceable dredging tooth according to any of the preceding claims, characterized in that the central passage (31) comprises a top passage portion- (32) in the tooth body top (29) having a mainly constant cross section (0) and a base passage portion (33) in the tooth body base (28) in which the opening of the central passage (31) is widened with respect to the opening forming the top passage portion (32) .

Replaceable dredging tooth according to claim 5, characterized in that the tooth point shaft (38) of the tooth point (37) is fitting slidingly into the top passage portion (32) of the tooth body (28) .

Replaceable dredging tooth according to claim 5 or 6, characterized in that the tooth point shaft (38) has a length (L) corresponding to the length (M) of the top passage portion (32) of the central passage (31) in the tooth body (28) .

Replaceable dredging tooth according to any of claims 5 to 7, characterized in that the top passage portion (32) in the tooth body (28) is a cylindrical passage (32) and that the tooth point shaft (38) is provided with a cylindrical part adjacent to the tooth point head (39) with an outside diameter (N) corresponding to an inside diameter (0) of the cylindrical top passage portion (32) and in that the tooth point locking means (40) provide in an axial location of the tooth point (37) into the tooth body (28) while allowing a rotation of the tooth point (37) in the top passage portion (32) of the tooth body (28).

Replaceable dredging tooth according to any of the preceding claims, characterized in that the tooth point locking means (40) consist of a circlip or snap ring (44) which can be snapped into a groove (43) provided in the tooth point shaft (38).

Replaceable dredging tooth according to any of claims 7 to 11, characterized in that the cross section of the base passage portion (33) enlarges in a direction from the top passage portion (32) to the tooth body base (30).

11. Replaceable dredging tooth according to any of claims 7 to 14, characterized in that the base passage portion (33) has an essentially non circular cross-section forming means for preventing an axial rotation of the dredging tooth (17) when mounted on the cutter head (8) .

Cutter head of a cutter suction dredger, which is a revolving body (8) rotatable around a central axis (AA' ) and which is intended for loosening bed rock or soil (4) when rotated in a working direction (BB' ) , the cutter head (8) comprising a ring (12) and a hub (13) at an axial distance (C) from one another and connected to one another by means of cutter arms (14), the cutter arms (14) being mainly flat blades shaped symmetrically around a central curved plane (HH' ) and having a front edge (15) and a back edge (16), the blades (14) being inclined towards the central axis (AA' ) in such a way that loosened bed rock or soil (4) is directed towards the central axis (AA' ) when the cutter head (8) rotates in the working direction (BB' ) , the front edge (15) of a cutter arm (14) being provided with at least one replaceable dredging tooth (17) according to any of the preceding claims, characterized in that the dredging tooth (17) is oriented in an axial direction (KK' ) which is mainly aligned within the above-mentioned central plane (HH' ) of the concerned cutter arm (14) and which is in a direction (KK' ) perpendicular to the front edge (15) at the position of the concerned replaceable dredging tooth (17).

13. Cutter head according to claim 12, characterized in that each cutter arm (14) is provided with multiple replaceable dredging teeth (17) according to any of claims 1 to 11, which are each oriented in the concerned above-mentioned axial direction (KK' ) .

Cutter head according to claim 12 or 13, characterized in that the cutter arms (14) are provided at their front edge (15) with sockets (18) arranged symmetrically with respect to the central plane (HH' ) of the concerned cutter arm (14), each socket (18) having a central opening (19) in which an adapter (20) is inserted with an insert part (21) having a shape which is complementary to the central opening (19) in the socket (18), and which adapter (20) is provided with an adapter head (26) extending out of the concerned socket (18) which adapter head (26) has a shape complementary to a base passage portion (33) of a central passage (31) into an afore-mentioned replaceable dredging tooth (1) in accordance with any of claims 1 to 11. 15. Cutter head according to claim 14, characterized in that the above-mentioned adapter head (26) is provided with a recess (36) and a corresponding replaceable dredging tooth (17) with tooth body connection means (35) comprising an inward directed lug (35) at one side (34) of the tooth body base (30) , the replaceable dredging tooth (17) being connected to the adapter (20) by means of a pin inserted between the lug (35) on the dredging tooth (17) and the recess (36) in the adapter head (26) .