JP2007508475A - Manipulator for dredge cutter head - Google Patents

Abstract

  Includes two robotic tooth handlers (64, 98) to remove the worn teeth (10) from the dredge cutter head (36) and to replace the worn teeth (10) with new teeth (48) Dredge cutter tooth manipulator. This manipulator is tailored to the dredger (24) and these two robotic tooth handlers (64, 98) are used to manipulate the cutter head (36) for these two robotic tooth handlers (64, 98). Is attached to the opposite side of the cutter platform (32) of the dredger (24) for winding to a position between.

Description

  The present invention relates to a manipulator (operating device) for a dredge cutter head.

  The dredge cutter head is used, for example, to collect material from the seabed. This cutter head is attached to the end of a cutter bucket extending from the hull of the dredger. The cutter head is rotated to excavate or grind along the seabed. The cutter head includes an arm. It has teeth attached to the leading edge of these arms. The opening between the arms forms an outlet (or channel) for collecting seabed material by the cutter head. Thus, material from the sea floor can be sucked up to the dredger along the cutter bucket from the opening between the arms, much like a large vacuum cleaner, to remove from the sea floor.

  Dredgers are often very large. For example, some cutter heads have a mass of about 30 tons (30,000 kg). The cutter head may have an outer diameter of about 3.5 m and a height or length of about 2.3 m. Some cutter heads have six spiral arms, each with possibly ten teeth. This will result in a total of 60 teeth on the cutter head. Each tooth alone has a mass of perhaps 20 kg.

  In use, these teeth engage or bite into the undersea material and break it apart or loosen it. But eventually the teeth wear out. It is therefore necessary to replace worn teeth regularly. In order to replace worn teeth, it is necessary to stop dredging work and lift the cutter bucket from the seabed to the cutter platform at the rear of the dredger. The cutter platform is completely free of water so that the personnel can perform this tooth change operation. When the damaged or worn teeth are replaced, the cutter bucket can be returned to the seabed. Then you can continue the habit. 9 and 10 show personnel changing the teeth of the cutter head.

  When dreding hard rock, typically 600 teeth need to be changed daily. It takes about 30 seconds to change each tooth. Maybe three people are needed to change teeth. Furthermore, it takes about 5 minutes in each direction to roll up and down the cutter bucket. In addition, approximately 20 to 30 teeth are replaced during each tooth replacement operation. Thus, this tooth replacement operation takes a significant amount of actual personnel time. Furthermore, the size of the teeth is limited by the individual's ability to handle these new and old teeth. Some national health and safety requirements actually limit the mass of each tooth to 20 kg. Furthermore, such a heavy cutter head is dangerous. Furthermore, the removal method can be dangerous. For example, when removing and replacing teeth manually, use a heavy tool such as a big hammer. Therefore, safety must be taken into account whenever personnel work near or near the cutter head or teeth. Therefore, it minimizes equipment downtime and personnel requirements and also allows the use of large teeth-large teeth are designed for large cutter heads and thus allow for fast dredges, a new for dredge cutter heads It would be desirable to provide a system. Larger teeth are more durable, so they do not need to be changed frequently.

  One system proposed in this field is to replace all cutter heads each time the cutter heads are rolled up and down. However, the cost of preparing multiple cutter heads is prohibitive; each cutter head has a mass of about 30 tons, which not only requires a large amount of raw material, but also has tolerances on the tooth position and the tooth mounting mechanism It is also a precision manufactured product with strict requirements. They are therefore expensive to produce. Furthermore, due to the weight of the cutter head, changing the cutter head is time consuming and dangerous. Furthermore, the mass of the cutter head is so heavy that it is necessary to install on the ship a very sturdy component in order to replace the cutter head. Therefore, this requirement proved to be a failure. Therefore, there is a need for an improved and more cost effective system.

The present invention is a dredge cutter tooth manipulator comprising at least one robotic tooth handler (handling device):
1. 1. Remove teeth from dredge cutter head; A manipulator is provided that includes means for replacing a removed tooth with a new tooth.

  The teeth are preferably secured to a cutter head on a spigot (plug) by a spigot pin passing through the teeth and spigot and attaching the spigot pin to them. Alternatively, the tooth can be mounted on a spiral spigot by fitting a spigot pin on the side of the spigot and tooth to prevent the tooth from falling out of the spiral. Alternatively, the teeth may be tack welded or glued onto the cutter head spigot. Therefore, this cutter tooth manipulator is provided with a hand for gripping the tooth and a pin driver for driving the spigot pin, or means for removing welding or bonding between the tooth and the spigot. For example, including a welding cutter or adhesive solvent.

  The manipulator preferably includes two robotic tooth handlers. The first removes the worn tooth and the second installs a new tooth that replaces the worn tooth.

  The hand is preferably attached to the first robotic tooth handler.

  A second hand may also be provided for grasping the new tooth and for securing the new tooth to the spigot. This fixation is preferably by means of a spigot pin, for example by driving the spigot pin through the tooth and the spigot or perhaps into the groove between the tooth flange and the side of the spigot. Fixing may alternatively be by welding or gluing the teeth to the spigot. The spigot preferably includes a helical element to assist in the correct alignment of the teeth on the spigot. The helical element is preferably a quarter turn helical screw.

  The second hand is preferably provided on a second robotic tooth handler.

  The manipulator is preferably mounted on the cutter platform of the dredger. Two robotic tooth handlers are preferably mounted on opposite sides of the cutter platform for winding the cutter head to a position between the two robotic tooth handlers.

  The manipulator is preferably mounted on a damper to isolate the manipulator from vibrations generated during dredging operations. These dampers are preferably fixable to prevent damping while the manipulator is processing the teeth.

  This or each robotic tooth handler preferably includes a multi-axis robot arm having a hand for engaging or grasping the cutter head teeth. This hand is preferably at the end of the arm.

  A motor or hydraulic system preferably drives the various elements of this or each multi-axis robot arm.

  A method for treating cutter teeth on a dredge cutter head is also disclosed.

  In a preferred embodiment of the present invention, a machine cutter tooth manipulator including two robotic tooth handlers for removing worn teeth from the machine cutter head and replacing the removed tooth (10) with a new tooth (48). Is provided. This manipulator is tailored to the dredger, and these two robotic tooth handlers are mounted on opposite sides of the dredger's cutter platform to wind the cutter head to a position between the two robotic tooth handlers. is there.

  Further preferred features of the invention are set forth in the claims appended hereto and will now be described purely by way of example with reference to the accompanying drawings.

  First, referring to FIG. 9 and FIG. 10, a tooth replacement method according to the prior art will be described. The worn tooth 10 provided on the spigot 12 is shown in both FIG. 10 and FIG.

  The teeth 10 are attached to the leading edge of the cutter head arm on a spigot 12 with spigot pins 14 which hold the tooth 10 in place on the spigot 12. This can be seen more clearly in FIGS. The first person 16 holds the first finger of the tooth removal tool 18 against the spigot pin 14. Next, the second person 20 drives the spigot pin 14 from the tooth 10 and the spigot 12 halfway with the tool 18 using the large hammer 22. The tool 18 is then rotated so that the second, long finger 15 of the tool 18 can be used to push the spigot pin completely out of the hole. Due to the long pins, a two-step procedure is required-the short fingers of the tool 18 are easier to align with the heads of the spigot pins 14 when starting to push the pins 14 out of the teeth 10 and spigots 12.

  A third person (not shown) then removes the old tooth 10 and replaces it with a new tooth 48 (not shown). The first person 16 then places a new spigot pin (or old spigot pin 14) on the tooth to hold the new tooth 48 on the spigot 12, and the second person 20 places it on the new tooth 48 and The spigot 12 is ready to be driven into the hole.

  Referring now to FIG. 1, a dredger 24 is shown. The dredger 24 includes a cutter bucket 26 having bucket hoist and lower wires 28 that are pulled into the ship 24 by pulleys (not shown), as shown by arrow 30. Raise towards the cutter platform 32. The raised position of the cutter bucket 26 is indicated by a dotted line 34 in FIG.

  The cutter bucket 26 has a cutter head 36 at its end. In use, the cutter head 36 engages the seabed 38 for dripping material from the seabed 38.

  At the raised position 34, the cutter head 36 is separated from the water surface 40. Accordingly, the tooth replacement operation is performed on the ship 24.

  This cutter head 36 is shown in more detail in FIGS. 2, 4, 6, 7 and 9. FIG. As can be seen, the cutter head 36 is generally hemispherical and includes a spiral arm that generally extends radially from the apex of the hemisphere toward the outermost edge of the hemisphere. However, they are twisted (ie, wrapped) around this hemisphere to form a slight helix. These arms are recessed or bent to form a leading cutting edge 44 having equally spaced tooth attachment locations 46 along it. In the embodiment shown in FIGS. 2 and 4, there are eight positions per leading edge 44. This provides for a total of 48 teeth. A discharge port or opening 42 is provided between the arms.

  Referring to FIG. 2, one new tooth 48 is shown attached to the cutter head 36. The teeth 48 are attached to a spigot similar to the four spigots 12 also shown in FIG. Referring to FIG. 4, teeth 34 and spigot 12 are more clearly shown. The spigot 12 may be attached to or made integrally with a tooth attachment location 46 provided on the cutter head 36.

  As shown in FIG. 9, additional teeth 50 can be provided on the outermost periphery of the cutter head 36. With these additional teeth 50, the total number of teeth on the cutter head increases to 54.

  More than eight tooth mounting positions 46 can be provided on the leading edge 44 of these arms. Furthermore, more than six arms can be provided. Similarly, fewer teeth can be provided at each leading edge, or fewer than 6 arms can be provided. However, for the purpose of this particular description, the cutter head 36 is provided with only 48 teeth 48.

  Referring to FIG. 11, the details of the preferred connection between the tooth 10 and the spigot 12 are shown. Teeth 10 are shown as worn teeth. To attach the tooth 10 to the spigot 12, a tooth 10 having a hole in the base (not shown) and sized to fit snugly over the spigot 12 (shown completely in FIG. 4) is placed on the spigot 12. So that the holes 52 (shown one) of the teeth 10 are aligned with the holes (not shown) of the spigot 12. A hole 52 in the tooth 10 is provided in a flange 54 extending from a base that engages a slot provided in the spigot 12. This helps to prevent teeth from rotating or misaligned on the spigot 12 because the flange is located in the slot. The spigot pin 14 is then driven into the hole to lock the tooth 10 in place on the spigot 12. The pin is secured to these holes with an engaging fit in both the opposing holes 52 of the teeth 10 and the holes of the spigot 12. This engagement fit is sufficient to prevent inadvertent removal of the pin in use. However, other attachment methods are possible, as will be readily appreciated by those skilled in the art, or as used in the field of dredge cutterheads.

  FIG. 8 shows an alternative configuration of the spigot 12. The spigot 12 itself has a square cross section across the axis, but is spiral along the axis. Accordingly, the spigot 12 has a helical-quarter turn helical screw.

  Three different teeth 48 with different tip shapes are also shown. There is a pick tip 110, a flare tip 112 and a chisel tip 114. These are suitable for different rock types.

  The teeth 48 and spigots 12 shown in FIG. 8 are well known in the acupuncture art, with the spigots 12 and teeth 48 being generally available from Esco® under the trademark Hellock®. These teeth (only one of which fits into each spigot) have holes in their bases 116 (not shown) of the same shape as this spigot to fit into and engage with the helical screw of the spigot 12. Have.

  At an installed position (not shown), the flange 117 of the tooth 48 faces the flat portion 115 of the spigot 12. Therefore, a spigot pin 14 in the form of an elongated piece of metal, not a cylindrical member, fits firmly in the gap between the flange 117 and the flat portion 115 to fix the tooth 48 on the spigot 12. Thus, the pin 14 fits against the flange 117 of the tooth 48 on the side of the spigot during use, preventing the tooth 48 from falling out of the spiral of the spigot 12.

  The pin 14 can later be removed from the spigot and tooth device by driving its bottom surface (not shown). This allows the teeth 48 to be removed from the spigot 12.

  In another configuration, not shown, the teeth may be tack welded (or otherwise welded) to the spigot. The pin 14 would then not be necessary. Alternatively, the teeth may be glued to the spigot. Suitable adhesives include high impact epoxies that can be pre-applied inside the tooth holes. The Exco Spherilock® system is particularly suitable in this regard, as is well known in the acupuncture art. In addition, the Esco Quadrolock® system is particularly useful as is well known in the dredge art.

  Thus, depending on the manner of coupling between the tooth 48 and the spigot 12, the cutter tooth manipulator hand is either a hand for gripping the tooth and a pin driver for inserting or removing the spigot pin, or a weld between the tooth and the spigot. Means for welding or unwelding, or means for bonding or unbonding, such as a welder / welding cutter or bonding means and an adhesive solvent dispenser. However, this adhesive means (or adhesive applicator) may not be necessary if the hole has been pre-applied with an adhesive, as in the case of Exco Spherilock® teeth.

  An embodiment for exchanging the type of tooth in which the manipulator of the present invention is fixed with a pin that penetrates both the tooth and the spigot will be described. However, one of ordinary skill in the art will readily appreciate that the hand can be properly modified to accommodate the various different types of tooth combinations that exist in the art.

  In accordance with the present invention, there is provided a dredge cutter tooth manipulator or robotic tooth handling device rather than manually changing teeth as was done in the prior art. As shown in FIG. 2, the manipulator includes two stations. The first station, tooth removal station 56, is shown on the left hand side of FIG. 2 and in FIG. A second station, a new tooth attachment station 58 is shown on the right hand side of FIG. 2 and in FIG.

  The cutter head 36 during cutter tooth operation (i.e., during the tooth change procedure) has been raised to the cutter platform 32 as in the prior art and as shown. However, in the present invention, the cutter head 36 has been raised to the same position on the cutter platform 32, but this time not between the personnel on the cutter platform 32 but between the two stations 56, 58, i.e. The personnel have now been replaced with the manipulator of the present invention.

  Referring now to FIG. 3, the tooth removal station 56 includes a waste depot 60 that includes two compartments 94, 96, a safety barrier 62, and a robotic tooth handler 64. The waste storage place 60 is located on the opposite side of the cutter head 36 of the robot type tooth handler 64. A safety barrier 62 is located between the waste yard 60 and the robotic handler 64 and covers a power line such as an electrical, hydraulic or pneumatic cable or tube to the robotic tooth handler 64.

  Instead of a waste repository, an array may be provided, for example for receiving worn teeth. This would make it easier to handle after removing the worn teeth. See the discussion below regarding the second station 58 for examples of suitable types of arrays.

  The robot type tooth handler 64 is a multi-axis robot including an arm and a hand for handling teeth on the cutter head 36. Since there are no parallel axes on the various teeth on this cutter head, multi-axis control is prepared. Furthermore, since the cutter head is rotatable, the axis of each tooth relative to the robotic tooth handler is variable. Therefore, the robotic tooth handler 64 guides the arm and hand for this multi-axis control and places the hand not only in the correct position but also in the correct direction so that the various teeth 10 can be placed one at a time. You can grab and operate one by one.

  The robotic tooth handler 64 is located on the table top 66. The table top 66 has a non-slip 68 at each end thereof. The robotic tooth handler 64 can be made to slide or move on the table top 66 by pulleys, belts or tooth racks (not shown). This allows the robotic tooth handler 64 to move along a line parallel to the axis of the cutter head 38 to help position the hand relative to each tooth along the leading edge 44 of the arm.

  The handler is mounted on a vibration damper that operates when the system is not in use. This protects the device during dredging; vibrations will not travel along the bucket from the cutter head to the cutter platform during dredging. These dampers prevent the manipulator from being damaged during dredging operations. However, when this manipulator is in use and the cutter head is located between the two stations 56, 58, the tooth operation requires accuracy. Thus, for example, a clamp (not shown) driven by a hydraulic cylinder tightens the damper so that the manipulator cannot move except for the movement necessary for the operation of this tooth.

  A turntable 73 is provided on the base 70 of the robot type tooth handler 64. This is because the robotic tooth handler around a vertical or first axis substantially perpendicular to the central axis of the cutter head 36 when the cutter head 36 is in its raised or wound position on the cutter platform 32. 64 can be rotated. This rotation is driven by a motor. However, like all moving parts of the robot, rotation or swinging of this handler may occur by other means well known to those skilled in the art, such as belts, gears or pneumatic or hydraulic means.

  Above the turntable, the robotic tooth handler 64 includes a plurality of linearly interconnected, swingable arm portions. They are effectively joined end to end, end in hand 90, and are roughly the same as conventional robot arms. The first arm portion 72 can rotate around a rotation shaft 74 mounted on the base bracket 76 of the robotic tooth handler 64. The first arm portion 72 has a further rotatable shaft 78 at its uppermost end, which has an axis parallel to the first axis 74. The second arm portion 80 is provided on the second rotation shaft 78. It is rotatable about a further rotatable shaft 82, which has an axis perpendicular to the first rotation axis 74. The second arm portion 80 is rotatable about an axis 82 about its own axis. This rotation is driven by a motor 84.

  The second arm portion 80 has an elbow 86 and a wrist 88 to allow accurate multi-axis operation of the hand 90. The hand 90 is attached to the end of the second arm portion 80. The hand 90 includes a tooth grasping mechanism and a spigot pin removal mechanism such as a hydraulic driver. It also includes a spigot pin gripping mechanism for grasping the spigot pins upon removal from the teeth and spigot assembly.

  Precise details of the hands and arm elements and their control systems are not provided; however, those skilled in the art of robotics and manipulators have the potential details of many possible implementations of such multi-axis arms and hands. You will find it easily. However, the arm and hand of the manipulator of the present invention must be designed to be strong enough to handle the force required to attach and remove teeth to and from the cutter head.

  Multi-axis robot arm designs other than those shown in the drawings will achieve this result, as will be apparent to those skilled in the art of robotics. However, there are preferably six motion axes, and the seventh motion axis is also provided by the sliding of the handler along the table top.

  FIG. 3 shows the tooth 10 being gripped by the hand 90. The multi-axis robotic tooth handler 64 is also shown swinging toward the waste repository 60 as indicated by arrow 92. When the hand 90 is swung over the waste storage place 60, the teeth 10 are dropped into the first compartment 94 of the waste storage place 60. The arm continues to swing and then drops a spigot pin (not shown) into the second compartment 96 of the waste storage 60. This spigot pin can generally be reused without reprocessing. However, since the tooth 10 is worn, it need not be reprocessed before it can be used again. That is why we classify the two items in this way.

  The manipulator of the present invention has a computer control system to guide the hand 90 over worn teeth that are not necessarily in a fixed position relative to the handler 64. Accordingly, the hand 90 shown in the drawings controls the robotic tooth handler 64, its arms and hands so that the computer control system sequentially engages and then removes any or all of the various worn teeth. And an optical tooth detection system (not shown) for positioning. Other position sensing systems can also be used, as is well known to those skilled in robotics.

  The software that drives the hand positioning control system can also be programmed to recognize the worn teeth as opposed to acceptable teeth and replace only the worn teeth. For example, image verification software can be used for this purpose.

  The cutter head rotation control can also be coupled to the control system for the robotic tooth handler 64. The cutter head is then rotated incrementally or in a stepwise fashion to move the leading edge 44, and thus the tooth 10, to the proper rotational position for easier handling of the tooth above it by the robotic tooth handler 64. it can.

  A second robot type tooth handler 98 is provided on the opposite side of the cutter head 38. Like the first robotic tooth handler 64, the second robotic tooth handler 98 is a multi-axis device. It has a base 100 mounted on the table top 102 having stops 104 (see FIG. 6) at each end so that the robotic tooth handler 98 can move on the table top 102 parallel to the axis of the cutter head 38. Further, the robot type tooth handler 98 has a rotatable or swingable arm portion and various rotary shafts and motors for driving these swinging or rotating portions. These arm portions and rotation axes are generally the same as or similar to the first robotic tooth handler 64. However, the hand of the second robotic tooth handler 98 is similar in design as a whole, but positions a new tooth 48 on the spigot 12 with the worn tooth 10 removed therefrom by the first robotic tooth handler 64. Is for.

  The computer control for the second robotic tooth handler 98 is linked to the computer control for the first robotic tooth handler 64 to indicate to which position new teeth are to be installed.

  Again, an optical position control system may be provided for the hand of the second robotic tooth handler 98. It will guide the hand to install new teeth or to pick up new teeth from the tooth supply. This optical control system may additionally be used to identify toothless spigots. This can work with or without the coupling that links the two computer controls together. It makes it possible to replace teeth that have fallen off the spigot, especially on the sea floor.

  A significant difference between the second robotic tooth handler 98 and the first robotic tooth handler 64 is that instead of the waste repository 60, an array of new teeth 48 is provided. This array of new teeth 48 is located on a tooth bench 106 that extends parallel to the axis of the cutter head 38. Three such tooth benches 106 are provided, each at a different height. The effect of this staggered placement is such that the teeth 48 on the other bench 106 do not interfere with the movement of the handler 98 so that the hands of the second robotic tooth handler 98 can more easily grasp the teeth 48 from different benches 106. To.

  These teeth are positioned tip-up so that the hand of the tooth handler 98 can place the lower hole of the teeth on the spigot 12 of the cutter head 38 without adjusting how the teeth 48 are gripped. It is.

  A spigot pin magazine dispenser 108 is provided at the end of the table top 102. The dispenser 108 includes a small container containing a number of new (or recycled) spigot pins 14. This container, and dispenser 108, operates in much the same way as a machine gun or rifle magazine. In addition to collecting the teeth 48 from the toothbench 106, the hand of the second robotic tooth handler 98 then collects the spigot pin magazine from one of the dispensers 108 as needed. The pins 14 in this magazine will be used to fasten new teeth 48 to the spigot 12 of the cutter head 38. A spigot pin grasping mechanism and a hydraulic driver (not shown) are provided on the hand to hold the pin 14 and drive it into the spigot 12 to attach a new tooth 48 to the spigot 12.

  Using the present invention with a cutter platform eliminates personnel from the dangerous environment of the cutter platform. This improves safety on the tugboat. Furthermore, the robot system can operate more quickly than personnel. Furthermore, the manipulator can be designed to handle teeth with a mass greater than 20 kg, so a large cutter head can be designed and attached to the dredger. Furthermore, the present invention allows automation of the tooth changing procedure without having to change the design of the cutter head or cutter bucket. In addition, the present invention can retrofit existing cutter platforms.

  The invention has been described purely by way of example. Changes in detail may be made to the invention within the scope of the claims appended hereto.

1 shows a dredger with a cutter head engaged with the seabed. 2 shows a preferred embodiment of a dredge cutter tooth manipulator according to the present invention on the dredge cutter platform of FIG. 3 shows details of the first station of the manipulator of FIG. Fig. 3 shows details of the dredger cutter head from Fig. 2; 3 shows details of the second station of the manipulator of FIG. 1 shows a plan view of a manipulator according to the invention. 1 shows a manipulator according to the invention in elevation. The spigot is shown with three alternative teeth for attachment to the spigot. An alternative cutter head is shown. Figure 3 shows a person operating a spigot pin removal tool for removing spigot pins from teeth and spigots according to prior art tooth removal methods. Fig. 11 shows two people about to begin removing the spigot pin of Fig. 10;

Claims (23)

With a dredge cutter tooth manipulator including at least one robotic tooth handler (64, 98):
1. 1. Remove tooth (10) from dredge cutter head (36); A manipulator including means for replacing the removed tooth (10) with a new tooth (48).   A manipulator according to claim 1, comprising a hand (90) for grasping a worn tooth (10) and for removing said tooth from said cutter head (36).   A manipulator according to claim 1 or 2, comprising a hand (90) for grasping a new tooth (48) and for attaching the new tooth (48) to the cutter head (36).   A manipulator according to claim 1, 2 or 3, wherein the teeth (10, 48) are for attachment to spigots (12) and are attached to these spigots (12), respectively. ) To lock the spigot pin (14) by penetrating the respective teeth (10, 48) and spigot (12).   A manipulator according to claim 1, 2 or 3, wherein the teeth (10, 48) are for attachment to spigots (12) and are attached to these spigots (12), respectively. The manipulator which can be locked by fitting this spigot pin (14) by the side of the respective spigot (12) and teeth (10, 48).   6. Manipulator according to claim 4 or 5, wherein the spigot pin (14) is supplied from a spigot pin magazine.   7. The manipulator according to claim 6, wherein the spigot pin magazine is held by a hand that handles new teeth of the manipulator.   The manipulator according to claim 1, 2 or 3, wherein the teeth (10, 48) are for attaching to the spigot (12) by tack welding.   8. The manipulator according to claim 1, 2, 3, or 7, wherein the teeth (10, 48) are for adhering to a spigot (12).   The manipulator according to any one of claims 4 to 9, wherein the spigot (12) is a quarter-turn spiral spigot.   A manipulator according to claim 10, wherein the spigot (12) comprises a quarter turn screw.   12. The manipulator according to any one of claims 4 to 11, wherein the spigot (12) is on a leading edge of an arm of the cutter head (36).   A manipulator according to any one of the preceding claims, comprising two robotic tooth handlers (64, 98).   The manipulator according to claim 13, wherein the first robotic tooth handler (64) removes the worn tooth (10) and the second robotic tooth handler (98) attaches a new tooth (48).   Manipulator according to any one of the preceding claims, comprising an optical position control system for guiding the manipulator to remove and replace the teeth (10, 48) on and off the cutter head (36).   A manipulator according to any one of the preceding claims for gripping a new tooth (48) from a supply (106) of a new tooth (48) and securing the new tooth (48) to the cutter head (36). A manipulator including a hand attached to a robotic tooth handler (98) for the purpose.   The manipulator according to claim 16, wherein the hand is provided in a second robot type tooth handler (98).   A manipulator according to any one of the preceding claims, comprising a multi-axis robot arm with a hand for engaging or grasping said teeth (10, 48) by said or each robotic tooth handler (64, 98). .   The manipulator of claim 18, wherein the or each hand is at the end of the or each arm.   Manipulator according to any one of the preceding claims, for modification on a cutter platform (32) of a dredger (24).   A manipulator according to any one of the preceding claims, wherein the manipulator is mounted on a damper for isolating the manipulator from vibrations external to the manipulator.   The manipulator according to claim 21, wherein the damper includes a clamp for preventing the damper from selectively functioning.   In a dredger (24) comprising a manipulator according to any of the preceding claims, the manipulator comprises two robotic tooth handlers (64, 98), which are two robotic tooth handlers (64, 98). Is opposed to the cutter platform (32) of this dredger (24) to wind the cutter head (36) to a position between these two robotic tooth handlers (64, 98) for tooth manipulation. A dredger attached to the side.

Images