U.S. patent application number 10/575157 was filed with the patent office on 2008-01-10 for dredger cuttertooth manipulator.
Invention is credited to Robby De Backer, Walter Dietens.
Application Number | 20080008546 10/575157 |
Document ID | / |
Family ID | 34307002 |
Filed Date | 2008-01-10 |
United States Patent
Application |
20080008546 |
Kind Code |
A1 |
Dietens; Walter ; et
al. |
January 10, 2008 |
Dredger Cuttertooth Manipulator
Abstract
The present invention addresses a dredger cuttertooth
manipulator that includes at least one robotic tooth handler that
is adapted to remove a worn tooth from a dredger cutterhead and
then replace the removed tooth with a new tooth. In a particular
embodiment, the manipulator includes two robotic tooth handlers,
one that removes the worn tooth, and another that replaces the
removed tooth with a new tooth. The robotic tooth handler is made
up of an arm and a hand that is adapted to grip the teeth.
Inventors: |
Dietens; Walter; (Herentals,
BE) ; De Backer; Robby; (Gent, BE) |
Correspondence
Address: |
MCCARTER & ENGLISH, LLP;BASIL S. KRIKELIS
Renaissance Centre, 405 N. King Street, 8th Floor
WILMINGTON
DE
19801
US
|
Family ID: |
34307002 |
Appl. No.: |
10/575157 |
Filed: |
October 5, 2004 |
PCT Filed: |
October 5, 2004 |
PCT NO: |
PCT/IB04/03443 |
371 Date: |
July 16, 2007 |
Current U.S.
Class: |
408/18 ;
901/2 |
Current CPC
Class: |
E02F 9/2891 20130101;
E02F 9/2866 20130101; E02F 5/006 20130101; Y10T 408/26 20150115;
E21C 35/1831 20200501; E02F 3/9212 20130101 |
Class at
Publication: |
408/18 ;
901/2 |
International
Class: |
E02F 9/28 20060101
E02F009/28 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 9, 2003 |
EP |
03256377.7 |
Claims
1. (canceled)
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23. (canceled)
24. A dredger cuttertooth manipulator comprising at least one
robotic tooth handler, wherein the manipulator is adapted to remove
worn teeth from a dredger cutterhead and replace said removed teeth
with new teeth.
25. The manipulator of claim 24, further comprising a hand adapted
to grip and remove said worn teeth from the cutterhead.
26. The manipulator of claim 25 wherein said hand is further
adapted to grip and mount said new teeth onto the cutterhead.
27. The manipulator of claim 24 wherein said dredger head comprises
at least one spigot adapted to accept said new teeth, and whereby
said hand is adapted to mount and removably lock said teeth onto
said spigot.
28. The manipulator of claim 27 wherein said hand further comprises
a spigot pin magazine.
29. The manipulator of claim 28 wherein the spigot pin magazine is
adapted to removably lock said teeth into said spigot by extending
a spigot pin through the respective tooth and spigot.
30. The manipulator of claim 28 wherein the spigot pin magazine is
adapted to removably lock said teeth into said spigot by fitting a
spigot pin at a side of the respective spigot and tooth.
31. The manipulator of claim 27 wherein the at least one spigot
further comprises a quarter-turn spiraled spigot.
32. The manipulator of claim 31, wherein the at least one spigot
comprises a quarter-turn thread.
33. The manipulator of any one of claim 27 wherein the at least one
spigot is disposed on a leading edge of an arm of the
cutterhead.
34. The manipulator of claim 26 said hand is further adapted to
grip a new tooth from a supply of new teeth and secure said new
tooth to the cutterhead.
35. The manipulator of claim 24 further comprising an optical
position control system, said control system adapted to maneuver
the manipulator to remove said worn teeth from and fit said new
teeth onto said cutterhead.
36. The manipulator of claim 24 further comprising a damper.
37. The manipulator of claim 36 further comprising a clamp designed
to prevent the damper from functioning.
38. The manipulator of claim 24 wherein said manipulator is
retrofitted for disposition on a cutterplatform of a dredger
ship.
39. A dredger cuttertooth manipulator comprising a first robotic
tooth handler and a second robotic tooth handler.
40. The manipulator of claim 39, wherein said first robotic tooth
handler is adapted to remove worn teeth from a dredger cutterhead
and the second robotic tooth handler is adapted to fit new teeth
into said cutterhead.
41. The manipulator of claim 40 wherein said second robotic tooth
handler is further adapted to grip a new tooth from a supply of new
teeth and secure the new tooth to the cutterhead.
42. The manipulator of claim 40, wherein each of the first and
second robotic tooth handlers further comprises an arm and a hand
adapted to grip said teeth.
43. The manipulator of claim 42 wherein each hand is disposed at
the end of each arm.
44. The manipulator of claim 39 further comprising a damper.
45. The manipulator of claim 44 further comprising a clamp designed
to prevent the damper from functioning.
46. The manipulator of claim 39 wherein said manipulator is
retrofitted for disposition on a cutterplatform of a dredger
ship.
47. A dredger ship comprising a dredger cuttertooth manipulator,
wherein said cuttertooth manipulator comprises a first robotic
tooth handler and a second robotic tooth handler, and wherein the
two robotic tooth handlers are mounted on opposed sides of a
cutterplatform on the dredger ship.
Description
[0001] The present invention relates to a dredger cuttertooth
manipulator.
[0002] A dredger cutterhead is used to extract material from, for
example, the seabed. The cufterhead is mounted at the end of a
cutterladder which extends from the hull of a dredger ship. The
cutterhead is rotated so that it drills or grinds along the seabed.
The cutterhead is provided with arms. It has teeth mounted on
leading edges of the arms. Openings between the arms form vents (or
channels) for the extraction of seabed material via the cutterhead.
Material from the seabed can therefore be sucked up through the
openings between the arms, along the cutterladder to the dredger
ship, for removal from the seabed, much like a large vacuum
cleaner.
[0003] Dredger ships are often very large. For example, some have
cutterheads having a weight of about 30 tonnes (30,000 kg). The
cutterhead may have an outer diameter of about 3.5 meters and its
height or length may be about 2.3 meters. Six spiral arms may be
provided on the cutterhead, each being edged with perhaps ten
teeth. This would provide a total of sixty teeth for the
cutterhead. Each tooth alone weighs perhaps 20 kg.
[0004] In use, the teeth engage or dig into the material on the
seabed to break it apart or to loosen it. Eventually, however, the
teeth will wear out Accordingly, it is necessary, regularly, to
replace the worn teeth. In order to replace the worn teeth, the
dredging operation needs to be stopped and the cutterladder needs
to be raised from the seabed up to a cutterplatform at the rear of
the dredger ship. The cutterplatform is clear of the water so that
the tooth change operation can be carried out by personnel on the
ship. Worn or broken teeth are then removed from the leading edges
of the arms by the personnel on the ship. Once the broken or worn
teeth have been replaced, the cutterladder can be returned to the
seabed. Dredging can then continue. FIGS. 9 and 10 show personnel
changing a tooth on a cutterhead.
[0005] When dredging hard rock, typically six hundred teeth need to
be replaced per day. It takes approximately 30 seconds to change
each tooth. Perhaps three people are required to change a tooth.
Further, the hoisting and lowering of the cutter ladder takes about
five minutes in each direction. Further, during each tooth change
operation, about 20 to 30 teeth are replaced. Accordingly, the
tooth change operation takes a considerable amount of real and
personnel time. Further, the size of the teeth are limited by the
capabilities of the individual who handles the old and new teeth.
Health and safety requirements in some countries actually limit the
weight of each tooth to 20 kg. Further the cutterhead, being so
heavy, is dangerous. Yet further, the method of removal can be
dangerous. For example, heavy tools such as sledgehammers are used
when manually removing and replacing the teeth. Safety, therefore,
needs to be taken into consideration whenever personnel are working
near or on the cutterhead or teeth. Accordingly, it would be
desirable to provide a new system for a cutterhead of a dredger
that will minimise equipment down times and personnel requirements,
and also which will allow larger teeth to be used - a larger tooth
will enable larger cutterheads to be designed and therefore faster
dredging. Larger teeth will also be more durable and therefore they
would need to be changed less frequently.
[0006] A system proposed in the art is to replace the entire
cutterhead upon each hoisting and lowering of the cutterladder.
However, the cost of providing multiple cutterheads is prohibitive;
each cutterhead not only weighs approximately 30 tonnes, so
involves a lot of raw materials, but is also a precisely
manufactured item, having close tolerance requirements for the
positions for the teeth and the tooth attachment mechanisms. They
therefore are expensive to produce. Further, due to the weight of
the cutterhead, replacing the cutterhead is a time consuming and
dangerous process itself Yet further the heavy weight of the
cutterhead requires a very substantial piece of equipment to be
installed on the ship for replacing the cutterhead. The equipment,
therefore, proved to be unsuccessful. An improved and more cost
efficient system is therefore required.
[0007] The present invention provides a dredger cuttertooth
manipulator comprising at least one robotic tooth handler, the
manipulator comprising means for: [0008] 1. removing a tooth from a
dredger cutterhead; and [0009] 2. replacing the removed tooth with
a new tooth.
[0010] Preferably the tooth is fixed to the cutterhead on a spigot,
a spigot pin extending through the tooth and the spigot to secure
it thereon. Alternatively, the tooth can be fitted on a spigot with
a spiral form, with a spigot pin being fitted at a side of the
spigot and tooth, to prevent the tooth from turning off the spiral
form Alternatively, the tooth may be tack-welded or glued onto a
spigot of the cutterhead. The cuttertooth manipulator, therefore,
comprises a hand for gripping the tooth and either a pin driver for
extracting the spigot pin or a means for disconnecting the weld or
glue between the tooth and the spigot, such as a weld cutter or
glue solvent.
[0011] Preferably the manipulator comprises two robotic tooth
handlers. The first removes worn teeth and the second fits new
teeth to replace the worn teeth.
[0012] Preferably the hand is fitted to the first robotic tooth
handler.
[0013] A second hand for gripping a new tooth and for securing the
new tooth to a spigot may also be provided. Preferably the
securement is with a spigot pin, for example by driving a spigot
pin either through the tooth and the spigot or between a flange of
the tooth and the side of the spigot, perhaps in a groove therein.
The securement may alternatively be by welding or gluing the tooth
to the spigot. The spigot preferably comprises a spiral element for
assisting in the correct alignment of the tooth on the spigot
Preferably the spiral element is a quarter-turn helical thread.
[0014] The second hand is preferably provided on a second robotic
tooth handler.
[0015] Preferably the manipulator is mounted on a cutterplatform of
a dredger ship. Preferably the two robotic tooth handlers are
mounted on opposed sides of the cutterplatform, for the cutterhead
to be hoisted into a position between the two robotic tooth
handlers.
[0016] Preferably the manipulator is mounted on dampers to isolate
the manipulator from vibrations caused during dredging operations.
Preferably the dampers can be clamped to prevent damping for when
the manipulator is manipulating teeth.
[0017] Preferably the or each robotic tooth handler comprises a
multi-axis robotic arm having a hand for engaging or gripping a
cutterhead tooth Preferably the hand is at the end of the arm.
[0018] Preferably motors or hydraulic systems drive the various
elements of the or each multi-axis robotic arm.
[0019] A method of manipulating cutterteeth on a dredger cutterhead
is also disclosed.
[0020] In a preferred aspect of the invention, there is provided a
dredger cuttertooth manipulator comprising two robotic tooth
handlers for removing a worn tooth from a dredger cutterhead and
for replacing the removed tooth (10) with a new tooth (48). The
manipulator is fitted to a dredger ship, the two robotic tooth
handlers being mounted on opposed sides of a cutterplatform of the
dredger ship for the cutterhead to be hoisted into a position
between the two robotic tooth handlers.
[0021] Further preferred features of the present invention are set
out in the claims appended hereto and will now be described, purely
by way of example, with reference to the accompanying drawings in
which:
[0022] FIG. 1 shows a dredger ship having a cutterhead engaged with
a seabed;
[0023] FIG. 2 shows a preferred embodiment of a dredger cuttertooth
manipulator in accordance with the present invention on a
cutterplatform of the dredger ship of FIG. 1;
[0024] FIG. 3 shows a detail of the first station of the
manipulator of FIG. 2;
[0025] FIG. 4 shows a detail of the cutterhead of the dredger ship
from FIG. 2;
[0026] FIG. 5 shows details of the second station of the
manipulator of FIG. 2;
[0027] FIG. 6 shows in plan a manipulator in accordance with the
present invention;
[0028] FIG. 7 shows in elevation a manipulator in accordance with
the present invention;
[0029] FIG. 8 shows a spigot with three alternative teeth for
mounting to the spigot;
[0030] FIG. 9 shows an alternative cutterhead;
[0031] FIG. 10 shows a man operating a spigot pin removal tool for
removing a spigot-pin from a tooth and spigot in accordance with a
prior art method of tooth removal; and
[0032] FIG. 11 shows two men about to start to remove the spigot
pin of FIG. 10.
[0033] Referring first to FIGS. 9 and 10, the method of changing a
tooth in accordance with the prior art will be described. A worn
tooth 10 provided on a spigot 12 is shown in both FIGS. 10 and
11.
[0034] The tooth 10 is attached to the leading edge of an arm of a
cutterhead on a spigot 12 with a spigot pin 14 holding the tooth 10
in place on the spigot 12. This can more clearly be seen in FIG. 4
or 9. A first person 16 holds a first finger of a tooth removal
tool 18 against the spigot pin 14. A second person 20 then uses a
sledgehammer 22 to drive the spigot pin 14 with the tool 18 part
way out of the tooth 10 and spigot 12. The tool 18 is then rotated
so that a second, longer, finger 15 of the tool 18 can be used to
drive the spigot pin fully out of the hole. The two step procedure
is required due to the length of the pin -a shorter finger of the
tool 18 will be more easy to align with the head of the spigot pin
14 when starting to drive the pin 14 from the tooth 10 and spigot
12.
[0035] A third person (not shown) then removes the old tooth 10 and
replaces it with a new tooth 48 (not shown). Then the first person
16 places a new spigot pin (or the old spigot pin 14) in the tooth
ready for the second person 20 to drive it through holes in the new
tooth 48 and the spigot 12 for retaining the new tooth 48 on the
spigot 12.
[0036] Referring now to FIG. 1, a dredger ship 24 is shown. The
dredger ship 24 comprises a cutterladder 26 having a ladder raising
and lowering wires 28 which, when pulled into the ship 24 by a
pulley (not shown), raises the cutterladder 26 towards a
cutterplatform 32, as shown by the arrow 30. The raised position
for the cutterladder 26 is shown in dotted lines 34 in FIG. 1.
[0037] The cutterladder 26 has a cutterhead 36 at a distal end
thereof The cutterhead 36, in use, engages the seabed 38 for
dredging material from the seabed 38.
[0038] In the raised position 34, the cutterhead 36 is clear of the
surface 40 of the water. Therefore, the tooth change operation is
carried out on board the ship 24.
[0039] The cutterhead 36 is shown in more detail in FIGS. 2, 4, 6,
7 and 9. As can be seen, the cutterhead 36 is generally
hemispherical and comprises coiled arms extending generally
radially from the apex of the hemisphere towards the outermost rim
of the hemisphere. However, they are twisted (i.e. coiled) around
the hemisphere to define a slight corkscrew. The arms are recessed
or angled to provide a leading cutting edge 44 having
tooth-mounting positions 46 equally spaced therealong. In the
embodiment shown in FIG. 2 and 4, there are eight positions per
leading edge 44. This provides for a total of 48 teeth. Vents or
openings 42 are provided between the arms.
[0040] Referring to FIG. 2, one new tooth 48 is shown fitted to the
Cutterhead 36. The tooth 48 is mounted on a spigot similar to the
four spigots 12 shown also in FIG. 2. Referring to FIG. 4, the
tooth 34 and the spigots 12 are shown more clearly. The spigots 12
are attached to, or will be formed integrally with, the tooth
mounting positions 46 provided on the cutterhead 36.
[0041] As shown in FIG. 9, additional teeth 50 can be provided
around the outermost circumference of the cutterhead 36. With these
additional teeth 50, the total number of teeth on the cutterhead is
increased to 54.
[0042] More than eight tooth-mounting positions 46 can be provided
on the leading edges 44 of the arms. Further, more than six arms
could be provided. Similarly, less teeth can be provided on each
leading edge or fewer than six arms can be provided. For the
purpose of this specific description, however, only 48 teeth 48 are
provided on the cutterhead 36. Referring to FIG. 11, a detail of a
preferred connection between a tooth 10 and the spigot 12 is shown.
The tooth 10 is shown as a worn tooth In order to attach the tooth
10 to the spigot 12, the tooth 10, which has an aperture (not
shown) in its base, sized to fit snugly over the spigot 12 (shown
in full in FIG. 4), is fitted over the spigot 12 so that holes 52
(one shown) in the tooth 10 align with a hole (not shown) in the
spigot 12. The holes 52 in the tooth 10 are provided in flanges 54
extending from the base that engage in a slot provided in the
spigots 12. This helps to prevent rotation or malalignment of the
tooth on the spigot 12 since the flanges locate in the slots. A
spigot pin 14 is then driven through the holes to lock the tooth 10
in place on the spigot 12. The pin locks in the holes with an
engagement fit in both the opposed holes 52 of the tooth 10 and the
hole in the spigot 12. The engagement fit is sufficient to prevent
inadvertent removal of the pin in use. Other methods of attachment
are, however, possible, as would be readily apparent to a skilled
person, or as also used in the field of dredger cutterheads.
[0043] FIG. 8 shows an alternative arrangement for the spigot 12.
The spigot 12 itself is square in section across its axis but
spiralled along its axis. The spigot 12, therefore, has a spiral
form--a quarter-turn helical thread.
[0044] Three different teeth 48 are also shown, with different
point shapes. There is a pick point 110, a flared point 112 and a
chisel point 114. These each are suitable for different rock
types.
[0045] The teeth 48 and the spigot 12 shown in FIG. 8 are generally
in accordance with spigots 12 and teeth 48 that can be obtained
from Esco (RTM) under the trademark Heliloc (RTM), which teeth are
well known in the art of dredging. The teeth (only one of which
will be fitted to each spigot) have an aperture (not shown) at
their bases 116 similarly shaped to the spigot for fitting onto and
mating with the helical thread of the spigot 12.
[0046] In the installed position (not shown), the flange 117 of the
tooth 48 will oppose a flat 115 of the spigot 12. A spigot pin 14,
in the form of a slip of metal, rather than a cylindrical member,
will then fit tightly into the gap between the flange 117 and the
flat 115 to secure the tooth 48 onto the spigot 12. The pin 14,
therefore, in use is fitted at a side of the spigot and against the
flange 117 of the tooth 48 to prevent the tooth 48 from turning off
the spiral form of the spigot 12.
[0047] The pin 14 can later be removed from the spigot and tooth
arrangement by driving its bottom face (not shown). This allows the
tooth 48 to be removed from the spigot 12.
[0048] In another arrangement, not shown, the tooth may be tack
welded (or otherwise welded) to a spigot. The pin 14 would then not
be required Alternatively, the tooth may be glued onto a spigot
Suitable glues include high-impact epoxy, which can be pre-applied
to the inside of the aperture of the tooth. The Exco Spherilok
(RTM) system, as well known in the art of dredging, is particularly
suitable in this regard. Further, the Esco Quadrilok (RTM system,
also well known in the art of dredging, is also particularly
useful.
[0049] Depending upon the form of connection between the tooth 48
and the spigot 12, the hand or hands of the cuttertooth
manipulator, therefore, comprises a hand for gripping the tooth and
either a pin driver for fitting/extracting the spigot pin, or a
means for welding or disconnecting the weld, or a means for
gluing/disconnecting the glue between the tooth and the spigot,
such as a welder/weld cutter or a gluing means and glue solvent
dispensing means. If the tooth, however, has glue pre-applied to
the aperture, such as is the case with Esco spherilok (RTM) teeth,
then the gluing means (or a glue applier) will not be required.
[0050] The manipulator of the invention will be described for an
embodiment for replacing teeth of the type secured with a pin
extending through both the tooth and the spigot A skilled person
will, however, readily appreciate that the hand or hands can be
appropriately adapted to suit the various different types of tooth
connection that exist in the art
[0051] In accordance with the present invention, instead of
manually changing these teeth, as done in the prior art, a dredger
cuttertooth manipulator or robotic tooth-handling device is
provided. As shown in FIG. 2, the manipulator comprises two
stations. The first station, the tooth removal station 56, is shown
on the left hand side of FIG. 2 and in FIG. 3. The second station,
the new tooth fitting station 58, is shown on the right hand side
of FIG. 2 and in FIG. 5.
[0052] The cutterhead 36 during cuttertooth manipulation (i.e.
during the tooth change procedure) is raised to the cutterplatform
32, as in the prior art, and as shown in the drawings. However,
with the present invention, the cutterhead 36, although being
raised to the same position on the cutterplatform 32, is now
positioned between the two stations 56, 58, rather than up to
personnel on the cutterplatform 32, i.e. the personnel are now
replaced by the manipulator of the present invention.
[0053] Referring now to FIG. 3, the tooth removal station 56
comprises a waste bin 60 comprising two compartments 94, 96, a
safety barrier 62 and a robotic tooth handler 64. The waste bin 60
is positioned on the opposite side of the robotic tooth handler 54
to the cutterhead 36. The safety barrier 62 is positioned between
the waste bin 60 and the robotic tooth handler 64 to cover power
lines such as electric, hydraulic or pneumatic cabling or pipes
that go to the robotic tooth handler 64.
[0054] Instead of a waste bin, an array, for example for receiving
worn teeth, can be provided. This would enable the worn teeth to be
more easily handled after removal. See the description below with
regard to the second station 58, for an example of a suitable type
of array.
[0055] The robotic tooth handler 64 is a multi-axis robot with an
arm and a hand for handling a tooth on the cutterhead 36.
Multi-axis control is provided since the various teeth on the
cutterhead do not have parallel axes. Further, the axis of each
tooth relative to the robotic tooth handler is variable since the
cutterhead is rotatable. The robotic tooth handler 64, therefore,
due to the multi-axis control, is able to manoeuvre its arm and
hand to position the hand not only in the right position but also
at the right orientation to grasp and manipulate the various teeth
10, one at a time.
[0056] The robotic tooth handler 64 sits upon a table top 66. The
table top 66 has sliding stops 68 towards each end thereof. The
robotic tooth handler 64 can be made to slide or move on the table
top 66 by pulleys, a belt or a toothrack (not shown). This allows
the robotic tooth handler 64 to be moved along a line parallel to
the axis of the cutterhead 38 for assisting in the positioning of
the hand relative to each tooth along the leading edge 44 of an
arm
[0057] The handler is mounted on vibration dampers that are active
when the system is not in use. This protects the equipment during
dredging operations; vibrations will be transmitted along the
ladder to the cutterplatform from the cutterhead during dredging
operations. The dampers prevent the manipulator from being damaged
during dredging operations. However, when the manipulator is in use
and the cutterhead is positioned between the two stations 56, 58,
accuracy is required for the manipulation of the teeth. Therefore,
clamps (not shown), for example driven by hydraulic cylinders,
clamp down the dampers so that there can be no movement of the
manipulators other than the movement required in order for
manipulation of the teeth.
[0058] On the base 70 of the robotic tooth handler 64, a turntable
73 is provided. This allows the robotic tooth handler 64 to be
rotated about a vertical or first axis that is substantially
perpendicular to the central axis of the cutterhead 36 when the
cutterhead 36 is in its lifted or hoisted position at the
cutterplatform 32. The rotation is driven by a motor. However, as
with all the moving parts of the robot, rotation or swinging of the
handler may be caused by other means well known to persons skilled
in the art, such as by belts, gears or pneumatic or hydraulic
means.
[0059] Above the turntable, the robotic tooth handler 64 comprises
multiple, linearly interconnected, swingable arm sections. They are
effectively joined end to end, terminating in a hand 90, much like
a conventional robotic arm. A first arm section 72 can be rotated
about an axle 74 that is mounted on a base bracket 76 of the
robotic tooth handler 64. This first arm section 72 has at its
uppermost end a further rotatable axle 78 which has an axis that is
parallel to the first axle 74. A second arm section 80 is provided
at the second axle 78. It is rotatable about a further rotatable
axle 82, which axle 82 has an axis perpendicular to the first axle
74. The second arm section 80 is rotatable about its own axis
around axle 82. This rotation is driven by a motor 84.
[0060] The second arm section 80 has an elbow 86 and a wrist 88 to
allow precise multi-axis manipulation of the hand 90. The hand 90
is mounted at the end of the second arm section 80. The hand 90
comprises a tooth grasping mechanism and a spigot pin removing
mechanism, such as a hydraulic driver. It also includes a spigot
pin grasping mechanism for grasping spigot pins upon removing them
from the tooth and spigot assembly.
[0061] Precise details of the hand and arm elements and their
control systems are not provided; a skilled person in the art of
robotics and manipulators will readily appreciate the potential
constructional details of the many possible incarnations of such a
multi-axis arm and hand. The arms and hands of the manipulator of
the present invention must be designed to be strong enough,
however, to be capable of handling the forces required to
manipulate the teeth off and onto the cutterhead.
[0062] Many multi-axis robotic arm designs other than that shown in
the drawings could achieve this result, as would as be apparent to
a person skilled in the art of robotics. However, there are
preferably provided six axes of movement, with a seventh axis of
movement also being provided by the sliding of the handler along
the tabletop.
[0063] In FIG. 3, a tooth 10 is shown grasped by the hand 90. The
multi-axis robotic tooth handler 64 is also shown to be swinging
towards the waste bin 60, as shown by arrow 92. Upon swinging the
hand 90 over the waste bin 60, the tooth 10 is dropped into a first
compartment of 94 of the waste bin 60. The arm continues to swing
and the spigot pin (not shown) is then dropped into a second
compartment 96 of the waste bin 60. The spigot pin can generally be
reused without reprocessing. However, the teeth 10, since they are
worn, will need to be reprocessed before they can be used again. It
is for this reason that the two items are sorted in this
manner.
[0064] The manipulator of the present invention has a computer
control system to guide hand 90 onto a worn tooth, which will not
necessarily be in a fixed position relative to the handler 64.
Therefore, the hand 90 shown in the drawings is fitted with an
optical tooth sensing system (not shown) to enable the computer
control system to control and position the robotic tooth handler
64, its arms and the hand so as to engage and then remove any or
all of the variously worn teeth, in turn Other position sensing
means can also be used, as would be well known to a person skilled
in the art of robotics.
[0065] The software driving the hand positioning control system
could also be programmed to recognise a worn tooth as opposed to an
acceptable tooth and only replace those teeth which are worn. Image
matching software can be used of this purpose, for example.
[0066] The rotation control of the cutterhead can also be connected
to the computer system for the robotic tooth handler 64. The
cutterhead can then be rotated incrementally to move the leading
edge 44, and therefore the teeth 10, to an appropriate rotational
position for the teeth thereon to be handled by the robotic tooth
handler 64 more easily, or in a stepwise manner.
[0067] On the opposite side of the cutterhead 38, a second robotic
tooth handler 98 is provided. As with the first robotic tooth
handler 64, the second robotic tooth handler 98 is a multi-axis
device. It has a base 100 mounted on a tabletop 102 having stops
104 (see FIG. 6) at each end thereof so that the robotic tooth
handler 98 can be moved on the tabletop 102 parallel to the axis of
the cutterhead 38. Further, the robotic tooth handler 98 has
rotateable or swingable arms sections and various axles and motors
for driving the swinging or rotating sections. These arm sections
and axles are generally the same as or similar to the first robotic
tooth handler 64. However, the hand on the second robotic tooth
handler 98, although generally similar in design, is for
positioning a new tooth 48 onto the spigots 12 that have had a worn
teeth 10 removed therefrom by the first robotic tooth handler
64.
[0068] The computer control for the second robotic tooth handler 98
is linked to the computer control for the first robotic tooth
handler 64 to instruct it as to which location to fit a new
tooth.
[0069] Again an optical position control system may be provided for
the hand of the second robotic tooth handler 98. It will guide the
hand for fitting new teeth or for picking up a new tooth from a
supply of teeth. The optical control system may in addition be used
to identify spigots without a tooth. This could work either with or
separate to the connection linking the two computer controls
together. It would in particular allow the replacement of teeth
that fell off spigots at the seabed.
[0070] A significant difference between the second robotic tooth
handler 98 and the first robotic tooth handler 64 is that instead
of a waste bin 60, an array of new teeth 48 is provided. The array
of new teeth 48 are positioned on tooth benches 106 that extend
parallel to the axis of the cutterhead 38. Three such tooth benches
106 are provided, each provided at a different height. This
staggered effect enables the hand of the second robotic tooth
handler 98 to grasp teeth 48 from the different benches 106 more
easily since the teeth 48 on other benches 106 will not interfere
with the movement of the handler 98.
[0071] The teeth are positioned point up so that the hand of the
tooth handler 98 will be able to position the aperture of the
underside of the tooth over the spigot 12 of the cutterhead 38
without adjusting its grip on the tooth 48.
[0072] At an end of the tabletop 102 there are provided spigot pin
magazine dispensers 108. The dispensers 108 contain small
containers containing a number of new (or recycled) spigot pins 14.
The containers, and the dispensers 108, operate in much the same
manner as a magazine of a machinegun or rifle. In addition to
collecting a tooth 48 from the tooth benches 106, the hand of the
second robotic tooth handler 98, as and when required, will collect
a spigot pin magazine from one of the dispensers 108. The pins 14
in the magazine will them be used for fastening the new tooth 48 to
the spigot 12 of the cutterhead 38. A spigot pin grasping mechanism
and hydraulic driver (not shown) is provided for the hand for
holding and driving the pin 14 through the tooth and spigot for
attaching the new tooth 48 to the spigot 12.
[0073] Use of the present invention on a cutterplatform removes
personnel from the dangerous environment of the cutterplatform.
This improves safety onboard the dredger ship. Further, the robotic
system is able to operate more quickly than personnel are. Yet
further, the manipulator can be designed to handle teeth having a
greater mass than 20 kg, therefore allowing larger cutterheads to
be designed and fitted to dredger ships. Yet further, the present
invention enables the automation of tooth change procedures without
any need to alter the design of the cutterhead or cutterladder.
Further, the present invention can be retrofitted to existing
cutterplatforms.
[0074] The present invention as been described above purely by way
of example. Modifications in detail may be made to the invention
within the scope of the claims appended hereto.
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