NO338508B1 - Belt trolley designed for use underwater - Google Patents

Description

TRACK CARRIAGE DESIGNED FOR USE UNDER WATER

The invention relates to a tracked vehicle designed to be used underwater, with an underside for placement against and suction to a surface. The tracked trolley can be used for transport or work, e.g. cleaning ship hulls, installing and removing plugs in hull penetrations and operating valves on underwater structures.

The biggest challenge with tracked vehicles that clean surfaces and perform other work tasks underwater is keeping the tracked vehicle stationary when it is exposed to forces from a control cable, possibly from a hose for collecting marine fouling, ocean currents or waves.

Known technology for transport and work under water includes several types of devices. For work offshore, remote-controlled vessels, so-called Remote Operated Vehicles or ROVs, are often used. An ROV moves in the water with the help of one or more propellers, and can to a certain extent stand still in relation to the place where it is carrying out work. If there is a solid object to grasp, the ROV can hold on to it with a manipulator arm equipped with a grappling claw. If there is a smooth surface that is stationary, the ROV can cling to it with an arm fitted with a suction cup. If the ROV gets stuck in a hull and is subjected to drag or rolling motion in the hull, it will easily swing around the place where it gets stuck, and will therefore often not get a sufficiently stable working position. A task currently carried out by ROVs is to install and remove plugs for hull penetrations in connection with the maintenance of valves on the inside of the hull penetration. Such work often depends on calm weather to be able to be carried out. With today's technology, the weather can thus delay the work.

Surfaces that have been submerged in water, especially seawater, will over time become covered with fouling. The fouling can be made up of organisms with a hard surface such as shells and barnacles, and by organisms with a soft surface such as crustaceans and algae. A surface that is initially smooth will become uneven after a while as it becomes covered with fouling. Fouling with shells in particular will give an uneven surface.

For cleaning hulls for marine fouling, there are several varieties of cleaning tools and methods for keeping the device that carries the cleaning tool stationary in relation to the surface being cleaned. The device can be kept stationary with propellers, or the device can be equipped with a negative pressure chamber that seals against the surface the device cleans, and a propeller or a pump device that creates negative pressure in the negative pressure chamber, so that the device is pressed against the surface. Other solutions include holding the device against the surface using magnets. Certain devices have an arrangement with two sets of suction cups which alternately stick to and move along the surface, so that the device moves discontinuously along the surface, which is undesirable in many cases.

A suction cup can be made of a relatively soft, elastic material. The edge of the suction cup against the substrate against which it is suctioned can thus be shaped somewhat depending on the nature of the substrate. The wall of the suction cup can be stretched out or compressed so that the height of the suction cup can vary. The wall of the suction cup can also be shaped corrugated so that the height of the suction cup can be further varied.

US4574722 describes a device which is wheel-driven and moves along a surface to be cleaned. A negative pressure in a negative pressure chamber holds the device against the surface. One disadvantage is that the vacuum chamber provides less holding power than when using a suction cup against the surface. The friction of the wheels against the surface determines the stability of the device. Another disadvantage is that a diver is needed to control the device. A larger staffing is therefore required to perform the task than if a remote-controlled device performs the same job.

US3906572 describes a device similar to the device described in US4574722, but the device is remotely controlled via a control cable. The facility can also form a platform for underwater work operations. A disadvantage of this construction is that if the device is to carry out work that exposes the device to large forces, the pressure in the negative pressure chamber must be so low that the friction between a gasket in the negative pressure chamber that seals against the surface, and the surface, becomes so great that the wheels that are supposed to ensure progress, will be able to spin during a movement.

US4270484 describes a device for carrying out measuring work. The device uses electromagnets to stick to the surface to be painted, in addition to a propeller as an additional aid. This device uses a wheel for propulsion on the surface. A disadvantage of electromagnets is that the magnets only create a holding force against the surface, and that it is the wheel's friction against the surface that determines the device's stability. Another disadvantage is that the device can only be used on magnetic surfaces. WO8502135A1 describes a tracked carriage comprising two chains with suction cups for positioning against a vertical or inclined surface. Negative pressure for the suction cups is controlled by separate valves for each suction cup. The tracked vehicle is relatively complicated. A vacuum pump produces negative pressure in the suction cups via a separate vacuum hose which is located in an operator panel. The crawler is not suitable for use in water. Furthermore, the vacuum hose can break when, for example, passing corners, so that the negative pressure disappears and the tracked vehicle loses its suction power against the surface it is suctioned to. A further disadvantage is that the device includes a cable in addition to the vacuum hose for controlling the device. This makes automatic handling of the tracked vehicle difficult when winding the vacuum hose on or off a drum.

US4664212 describes a tracked carriage comprising two belts with recesses on the outside for placement against a surface. Support beams with vacuum chambers are located under the belts and on the opposite side of the recesses. Holes through the belts form a connection between the vacuum chambers and the recesses. A negative pressure is thereby created in the recesses when there is negative pressure in the negative pressure chambers. The belts with the recesses stick to the surface. The design of the belts is an alternative to using suction cups. The belts are specially designed to be able to move over a rough surface such as a rough concrete surface. Ordinary suction cups wear easily on such a surface and the crawler can fall down due to a lack of holding power. A disadvantage of this tracked trolley is that it does not have guides that hold the tracks against the support beams. In the event of a load on the tracked vehicle in a direction away from the surface, leakage of ambient air into the connections between the belt recesses and the negative pressure chambers can thus occur, so that the negative pressure is reduced or disappears, and the suction against the surface ceases. The tracked vehicle has air ejectors to create negative pressure, and is equipped with air-driven motors for propulsion. The device will therefore not be able to function in water. Another disadvantage is expensive and specially made belts, as well as the fact that the edges of the many negative pressure chambers will cause a lot of wear and tear on the belt. A further disadvantage is that the belts will have to be driven in separate directions, or the belt must be driven only on one side of the tracked vehicle, in order for the tracked vehicle to be able to change direction. The suction cups will then slide the surface, with consequent wear and tear, as well as the risk of losing its attachment to the surface the crawler is attached to.

EP0710188B1 describes a tracked vehicle comprising two chains with suction cups for positioning against a surface. Rails with grooves provided with channels are located under the chains on the opposite side of the suction cups. Pipes through the chains form a connection between the suction cups and the channels, which in turn are connected to a source of negative pressure. Negative pressure can thus propagate from the source of negative pressure, via the channels and pipes of the suction cups, so that they suck firmly to the surface. The channels are fitted with lips that rest against the belts on the chains, and ensure a seal between the channels and the belts. Each link in the chains is provided with a projection which is controlled by a groove in the rail. The tracked vehicle is relatively complicated.

The purpose of the invention is to remedy or to reduce at least one of the disadvantages of known technology, or at least to provide a useful alternative to known technology.

One purpose of the invention is to produce a tracked vehicle where the construction is relatively simple, where the connection between the suction cups and the source of negative pressure is simple and robust, while also being tight to the surroundings, where the belt solution is simple and the belts are guided stably, and where there are few valves and control devices, so that the tracked vehicle is affordable to produce and has high reliability. The purpose is also to produce a tracked vehicle which, compared to known tracked vehicles, is well suited for carrying out work operations under water. One purpose is to produce a crawler that is suitable for installing and removing plugs in hull penetrations underwater. A further object is to produce a tracked vehicle which, compared to known tracked vehicles, is better able to perform cleaning of surfaces under water in a remotely controlled operation.

The purpose is achieved by the features indicated in the description below and in the subsequent patent claims.

The invention is defined by the independent patent claim. The independent claims define advantageous embodiments of the invention.

In a first aspect, the invention relates to a tracked vehicle designed to be used underwater, with an underside for placement against a surface, comprising: - at least two wheels and a drive device for operating at least one of the two wheels; - a belt extending around and between the wheels, where the belt between the wheels extends in an inner part and an outer part, where an outside of the outer part of the belt forms the underside of the tracked vehicle; - a rail positioned within an inside of the outer part of the belt;

- suction cups on the outside of the belt for placement against the surface; and

- a suction device in fluid connection with the suction cups so that a negative pressure is produced in the suction cups when the suction cups on the outside of the outer part of the belt are placed against the surface, and the tracked vehicle is thereby held firmly against the surface,

and such that:

- each suction cup is provided with a neck; - the neck is attached to the belt; - the neck comprises at least one slot; - an internal channel extends through the neck and belt; - a guide fixed in the tracked vehicle comprises at least one guide rib positioned in the slot when the suction cups are on the outside of the outer part of the belt; and - a fluid connection is formed by a vacuum tube, a vacuum chamber and the internal channel between the suction device and the suction cup.

The guide can be made up of two longitudinal guide ribs on opposite sides of the neck of the suction cup. The guide can be attached to the rail.

The neck of the suction cup may be provided with a circular groove; and a guide rib can in its longitudinal direction be provided with a longitudinal bead so that the bead can be positioned in the groove when the suction cup is on the outside of the outer part of the belt. The suction cup can be attached to the belt with a tube to a fixing block on the inside of the belt. The suction cup can be attached to the belt with a continuous connection to a fastening block on the inside of the belt.

The belt can mainly lie tightly sliding against the rail in a sealing area. The rail can have at least one vacuum chamber fluidly connected to the suction device with the vacuum tube, and the vacuum chamber can be fluidly connected to the internal channel through a longitudinal opening. The rail can have two negative pressure chambers fluidly connected to each suction device with its own negative pressure tube, and the two negative pressure chambers can be in fluid connection with different internal channels.

The rail may have a recessed longitudinal middle portion which is open to the belt, and the recessed middle portion may be fluidly connected to the suction device with the negative pressure tube, so that a negative pressure chamber is formed between the rail and the belt, and the negative pressure chamber is fluidly connected to the internal channel.

The negative pressure chamber can be elongated.

A procedure for changing the direction of travel of a tracked vehicle as described above is also described. Fixing plane means a plane formed by the suction cups on the underside of the tracked vehicle. When the suction cups are fixed to the surface, the attachment plane coincides with the surface. Actuators can move the suction cups from a position above the attachment plane, towards and past the attachment plane and back. The suction cups can be movable collectively or individually. The number of holders, actuators and suction cups may be different from the four shown.

Based on the fact that the tracked vehicle is fixed to a surface such as the surface mentioned above, using the suction cups, the change of the tracked vehicle's direction of travel includes the following steps: - advancing at least two of a turntable's suction cups to the attachment plane, to position against the surface; - generation of negative pressure between the rotary table's suction cups and the surface, so that the rotary table's suction cups suck firmly to the surface; - removal of negative pressure between the belt's suction cups and the surface, so that the belt's suction cups detach from the surface; - further advancement of the rotary table's suction cups, past the attachment plane, so that the belt's suction cups and the frame structure of the tracked carriage are raised from the surface; - rotation of the turntable in relation to the frame structure, so that the frame structure is rotated in relation to the surface; - retraction of the rotary table's suction cups to the mounting plane, so that the belt's suction cups are placed against the surface; - generation of negative pressure between the belt's suction cups and the surface, so that the belt's suction cups suck firmly to the surface; - removal of negative pressure between the rotary table's suction cups and the surface, so that the rotary table's suction cups detach from the surface; and - further retraction of the turntable's suction cups from the attachment plane, so that the turntable's suction cups are moved away from the surface.

The frame construction, which forms the main part of the tracked vehicle, has thus been rotated and given a new longitudinal direction, which is also the tracked vehicle's new direction of travel. If necessary, the above steps are repeated until the tracked vehicle has obtained the desired direction of travel.

Also described is a plug tool for installing and/or removing a plug in a hull penetration using a crawler as described above and a method for using the plug tool to install and/or remove a plug in a hull penetration . The plug tool may comprise two or more linear actuators mounted on a rotary table. The linear actuators may have piston rods which are fixed in a plug holder which includes a locking device for the plug. The locking device can be a hydraulic actuator. The plug tool may also include a linear actuator with a piston rod having a hydraulic male coupling for engagement with a corresponding hydraulic female coupling in the plug for applying hydraulic pressure. The linear actuators can be electric, or they can be hydraulic cylinders.

The plug is locked to the plug holder, and the hydraulic male coupling is inserted into the hydraulic female coupling before launching the tracked vehicle. The crawler is then positioned at and secured to the surface with the suction cups as described above, with the plug over the hull penetration. The linear actuators are then stretched out, so that the plug is displaced towards the surface and into the hull passage. Hydraulic pressure is then applied to the plug through the hydraulic couplings, which in a known manner causes a gasket in the plug to expand against a sealing surface in the hull passage, so that the plug is locked. The actuator is then pulled back, so that the male coupling is pulled out of the female coupling. The locking device is released, so that the plug is released from the plug holder. The linear actuators are then pulled back, so that the plug holder is removed from the plug. The plug is now installed in the hull bushing, and the crawler can be detached from the surface and removed. The above can be repeated in the opposite order when the plug is to be removed from the hull penetration. Instead of the linear actuator with the hydraulic male coupling, the plug tool can alternatively be equipped with a motor or actuator to operate a mechanically operable plug.

In what follows, examples of preferred embodiments are described which are illustrated in the accompanying drawings, where: Fig. 1 shows a front view of a tracked vehicle according to the invention; Fig. 2 shows a side view of the tracked vehicle according to the invention; Fig. 3 shows a view from below of the tracked vehicle according to the invention; Fig. 4 shows on a larger scale a cross-section laid along section line A-A in fig. 2 of one embodiment of the invention; Fig. 5 and 6 show cross-sections laid along section line A-A in fig. 2 of another embodiment of the invention; Fig. 7 shows a cross-section laid along section line A-A in fig. 2 of a further other embodiment of the invention; Fig. 8 shows the same as fig. 4 with an alternative embodiment of a suction cup; Fig. 9 shows the same as fig. 4 with an alternative design of a guide and a suction cup neck; Fig. 10 shows a view on a smaller scale from below where the crawler is mounted

a buoyant body; and

Fig. 11 shows a view from the front where the tracked vehicle is fitted with a tool for installing and removing a plug in a hull passage. Fig. 1-3 show a tracked vehicle according to the invention, respectively from the front, from the side and from below, for use when working underwater.

Direction indications, such as "bottom side", "longitudinal direction", "side direction", "vertical direction", etc. refer to the tracked vehicle when it is standing on a horizontal surface. With reference to fig. 1-3, which show x, y and z direction, "longitudinal direction" is x direction, in the horizontal plane, coinciding with the track carriage's direction of travel. "Lateral direction" ery direction, in the horizontal plane, across the track carriage's direction of travel, and "vertical direction" is z direction. Such directions are used for practical reasons to describe the tracked vehicle, and should not be understood as restrictive, as an important feature of the tracked vehicle is that it can be used underwater in any orientation.

In the drawings, the reference number 100 denotes a tracked vehicle. The tracked vehicle 100 comprises a frame construction 1 mounted on at least two wheels 2, one wheel 2 at the front and one wheel 2 at the rear. In the drawings, the tracked vehicle 100 is shown with four wheels 2 with two wheels 2 on each side of the tracked vehicle 100. The tracked vehicle 100 is provided with a drive device 19 for operating at least one of the wheels 2 (see Fig. 3). The wheels 2 can be connected in pairs with a continuous axle 9, or each wheel 2 can be provided with a separate axle 9. A belt 4 runs around and between the wheels 2 on each side of the tracked carriage 100. Between the wheels 2, the belt 4 runs in an inner part 29 and an outer part 30, where an outside of the outer part 30 of the belt 4 forms an underside of the tracked carriage 100. A rail 31 (see fig. 4, 8, 9) is placed inside an inside of the outer part 30 of the belt 4, and is fixed in relation to the frame structure 1. The belt 4 is provided on its outside with suction cups 5 with suction surfaces facing away from the belt 4.

The tracked vehicle 100 also comprises a suction device 50 which is in fluid connection with the suction cups 5. The suction device 50 can be any device that produces a negative pressure in relation to the ambient pressure in the water surrounding the tracked vehicle 100. The suction device 50 can e.g. be a pump (not shown) which is mounted in the tracked vehicle 100 or a hose connection to a pump which is on a boat deck (not shown).

The tracked vehicle 100 further comprises propellers 17 for moving the tracked vehicle 100 in the longitudinal direction and lateral direction, and propellers 18 for moving the tracked vehicle 100

in the vertical direction.

The drive device 19 for at least one of the wheels 2 and drive devices (not shown) for the propellers 17, 18 can be electric, pneumatic or hydraulic motors. Electric motors can be supplied with energy from batteries (not shown) or via a cable 23 from e.g. a boat (not shown). Pneumatic or hydraulic motors can be supplied with compressed air or hydraulic fluid through an umbilical cord (not shown). As an alternative, the tracked vehicle 100 may be provided with an electrically driven hydraulic pump (not shown) which is supplied with electrical power from batteries or via the cable 23. In addition to these energy consumers, the tracked vehicle 100 also contains actuators (not shown), which may be electric, pneumatic or hydraulic, sensors, valves and control devices, and possibly cameras, lights and tools, which can be supplied with energy from batteries, through the cable 23 or from an electrically driven hydraulic pump. The crawler 100 can be controlled remotely through the cable 23, or it can be controlled by a diver (not shown). A yoke 22 keeps the cable 23 at a distance from moving parts that can damage the cable 23.

The belt trolley 100 as shown in fig. 1-3 have negative buoyancy in water. It can therefore be positioned underwater with a lifting device (not shown).

Fig. 10 is a view from below of the tracked vehicle 100 fitted with a buoyancy body 24, so that it has approximately neutral buoyancy in water. When the tracked vehicle 100 has approximately neutral buoyancy, it can be positioned with the propellers 17, 18.

In use, the belt trolley 100 is positioned with the suction surfaces of the suction cups 5 on the outside of the outer part 30 of the belt 4 facing a surface 28, see fig. 2. The surface 28 can be a ship's side. The suction device 50 produces negative pressure between the suction cups 5 and the surface 28, so that the suction cups 5, and thus the belt 4 and the tracked carriage 100, are sucked firmly to the surface 28. Fig. 3 shows the tracked carriage 100 from below, fitted with a brush tool 20 which is equipped with a raise/lower device 21. Fig. 4 shows a cross-section laid along section line A-A in fig. 2 of one embodiment of the invention. Each suction cup 5 is provided with a neck 5b, and the neck 5b is attached to the belt 4. The neck 5b has an internal channel 32 which forms part of a fluid connection between the suction device 50 and the suction cup 5. A guide 6 which is fixed in relation to the frame structure of the tracked vehicle 100 1, guides the necks 5b of the suction cups 5 in the longitudinal direction of the belt 4. The guide 6 in Figures 4-8 consists of a longitudinal inner guide rib 61 on the side of the suction cup 5 neck 5b which faces the central part of the tracked vehicle 100, and a longitudinal outer guide rib 63 on the opposite side of the suction cup 5 neck 5b. The guide 6 holds the neck 5b and consequently the belt 4 in the transverse direction of the belt 4.

The guide ribs 61, 63 are attached to the rail 31. The rail 31 is attached to a bracket 3

which is attached to the frame construction 1, see fig. 1. The guide ribs 61, 63 could alternatively have been attached to the bracket 3 or further alternatively directly or indirectly to the frame structure 1 in another way. Fig. 1 and fig. 4-8 show fastening of the rail 31, the guide ribs 61, 63 and the bracket 3 with bolts. Alternatively, some or all of these fixings could have been welded connections.

The neck 5b of the suction cup 5 has an internal guide lip 33 and an external guide lip 34 which are positioned on the inside and outside of the inner and outer guide ribs 61, 63, respectively. The guide lips 33, 34 form a slot 54 between them. The guide ribs 61, 63 are positioned in the slot 54 as follows that the belt 4 is prevented from lifting up from the rail 31.

The inner channel 32 of the neck 5b is in fig. 4 formed by a tube 52 which forms a continuous connection from the suction cup 5, through the neck 5b, through the belt 4 and through a fastening block 5c. The attachment block 5c is recessed in the belt 4 from the inside of the belt 4, where the underside of the attachment block 5c is essentially flush with the inside of the belt 4. The suction cup 5 and the belt 4 are made of elastic materials, typically an elastomer. The neck 5b and the fixing block 5c can be made of a stiffer material, where the stiffer material can be a polymer which can also be an elastomer. The tube 52 which forms the channel 32 can be made of metal, e.g. 316 stainless steel. Depending on the choice of materials for the various components, they can be cast together, glued together, vulcanized together, attached to each other by heat treatment or attached to each other by a threaded connection. The pipe 52 can also be provided with a fastening collar at one or both ends (not shown).

The rail 31 in fig. 4, 8, 9 are shown as a channel profile, but other shapes can also be used, for example a pipe. An opening 8b in the form of a longitudinal slit in the rail 31 forms a connection between an internal cavity 8 in the rail 31 and the channel 5b of the neck

32. The inner diameter of the channel 32 may correspond to the width of the opening 8b. The inner diameter of the channel 32 may be somewhat smaller than the width of the opening 8b. Channel 32 interior

diameter may be somewhat larger than the width of the opening 8b. It is advantageous that the width of the opening 8b is narrow and the inner diameter of the channel 32 is small, as this reduces the resistance that the belt 4 must overcome to be displaced along the rail 31. The width of the opening 8b and the inner diameter of the channel 32 cannot be too small as this will reduce the fluid flow in the suction cup 5 and thus the negative pressure that is created to provide holding power against the substrate 28.

A negative pressure pipe 10 forms a connection between the cavity 8 of the rail 31 and the suction device 50. Control devices, not shown, such as switches, regulators and valves, can switch on and off and possibly control the negative pressure in the negative pressure pipe 10. When the pressure in the negative pressure pipe 10 is less than the ambient pressure, a negative pressure in the rail's 31 cavity 8, which can then be termed a negative pressure chamber. Water and possibly air will be sucked in from the area between the suction cup 5 and the surface 28, see fig. 2, through the neck 5b channel 32, into the negative pressure chamber 8 and further through the negative pressure pipe 10 to the suction device 50. A negative pressure is thus created between the suction cups 5 and the surface 28, so that the suction cups 5 are sucked firmly to the surface 28. The belt 4 is essentially close to and slides with its inside against the rail 31 in a sealing area 36. The sealing area 36 ensures that surrounding water, possibly air, is not or only in a limited amount sucked into the vacuum chamber 8 between the belt 4 and the rail 31.

Fig. 5 and 6 show cross-sections laid along section line A-A in fig. 2 in an alternative embodiment where a rail 31' comprises two vacuum chambers 8' and 8" which are connected to their respective suction devices 50 through respective vacuum tubes 10', 10". A bolt 35 connects the suction cups 5', 5" with respective necks 5b', 5b", the belt 4 and respective fastening blocks 5c', 5c", in a similar way as explained for the tube 52 which forms the channel 32 in Fig. 4. Fig. 5 shows a continuous channel 32' which is shifted laterally in relation to the channel 32 in Fig. 4, and which forms a connection from the suction cup 5' to the underside of the fastening block 5c', to correspond with a longitudinal slot 8b' in the rail 31'. 6 shows the corresponding side-displaced channel 32" which forms a connection from the suction cup 5" to the underside of the attachment block 5c", to correspond with a longitudinal slot 8b" in the rail 31'. The suction cups 5', 5" are placed along the belt 4, e.g. . alternately, so that the suction effect from the two vacuum chambers 8', 8" is distributed between the suction cups 5', 5". This results in two negative pressure circuits. The rail 31' is between the longitudinal slot 8b' and the longitudinal slot 8b", provided with a longitudinal seal 361. The fastening blocks 5', 5" lie sealingly against the longitudinal seal 361. The longitudinal seal 361 can be made of a resilient material, which for example a rubber or a synthetic elastomer such as polyurethane. If the negative pressure decreases or disappears in one negative pressure circuit, which may be due to a fault in the circuit, leakage between the belt 4 and the rail 31' in the sealing area 36, or that a suction cup 5', 5" detaches from the surface 28 to which it is attached, the suction cups 5 ', 5" in this circuit get reduced or lose their suction effect. However, the suction effect of the suction cups 5', 5" in the second negative pressure circuit will not be affected.

The negative pressure chambers 8, 8', 8" in Fig. 4-6, 8, 9 are included as part of the rail 31, 31'. The rail 31, 31' extends between the wheels 2, which hold the belt 4, and is terminated in a small distance from the wheels 2. The vacuum chambers 8, 8', 8" can, however, be divided into several separate vacuum chambers placed one after the other as part of or connected to the rail 31, 31' (not shown).

The slits 8b, 8b', 8b" are, with reference to Fig. 4-6, 8, 9, referred to as longitudinal slits 8b, 8b', 8b". These gaps can extend over the entire length of the negative pressure chambers 8, 8', 8". The gaps 8, 8', 8" can alternatively be made up of several short, elongated openings, or many small openings which together provide sufficient connection between the negative pressure chambers 8, 8 ', 8" and the channels 32, 32', 32" in the suction cups' 5, 5', 5" necks 5b, 5b', 5b". It is only on the part of the outer part 30 of the belt 4 that rests against the rail 31, 31' between the wheels 2, that the necks 5b, 5b', 5b" channels 32, 32', 32" are in connection with the vacuum chambers 8, 8 ', 8" openings 8b, 8b', 8b", so that the suction cups 5, 5', 5" receive negative pressure and suck to the surface 28. When a part of the belt 4 is either around one of the wheels 2, or in a position where the belt 4 is about to make contact with or leave the surface 28, or in the inner part 29 of the belt 4, there is no negative pressure in the suction cups 5, 5' 5". Fig. 7 shows a cross-section laid along section line A-A in fig. 2 of an alternative rail 31" with a recessed longitudinal central portion 37 which is open to the belt 4. The recessed central portion 37 is in fluid connection with the suction device 50 via a negative pressure pipe 10, so that a negative pressure chamber 38 is formed between the recessed central portion 37 of the rail 31" and the belt 4. The channel 32 in the neck 5b of the suction cup 5 propagates the negative pressure from the negative pressure chamber 38 to the suction cup 5. The negative pressure in the negative pressure chamber 38 simultaneously sucks in the belt 4, so that the belt 4 is pressed against the rail 31" in the sealing areas 36 on the sides of the recessed central part 37. This improves the seal between the belt 4 and the rail 31", and helps to ensure the suction effect of the suction cups 5 in that no water or air is drawn in between the belt 4 and the rail 31". Such an embodiment increases the resistance between the belt 4 and the sealing area 36 when the belt 4 is displaced in relation to the rail 31. Fig. 8 shows a cross-section laid along section line A-A in Fig. 2 of an alternative design of the suction cup 5. Su the wall 53 of the suction cup 5 is formed as a corrugated wall 53 or a bellows-shaped wall 53. This increases the ability of the suction cup 5 to stretch or compress so that the suction cup 5 will stick to a more uneven surface. It also increases the possibility that the mouth part 59 of the suction cup 5 can be inclined in relation to the belt 4. This is advantageous on uneven surfaces and where the surface has curvatures with relatively small radii. All the mentioned suction cups 5, 5', 5" can have a wall 53 formed as a corrugated wall 53 or a bellows-shaped wall 53. Fig. 9 shows a cross-section laid along section line A-A in Fig. 2 of an alternative design of a guide 6 A guide rib 65 is, in its edge portion facing the neck 56 of the suction cup 5, provided with a longitudinal bead 67 in the length of the guide rib 65. In the bottom 55 of the gap 54 between the guide lips 33, 34, the neck 56 is provided with a circular groove 57 with a diameter somewhat larger than the diameter of the bead 67, as shown in Fig. 9. The distance between the guide lips 33, 34 is smaller than the diameter of the bead 67. The suction cup 5 and the belt 4 cannot move laterally in relation to the guide 6' as the bead 67 cannot be displaced out of the groove 57 in a direction perpendicular to the longitudinal direction of the rail 31. The suction cup 5 and the belt 4 cannot be lifted up from the rail 31 either. The through channel 32 of the suction cup 5 is laterally displaced in relation to the center of the suction cup 5. Correspondingly, fe the glass block 5c is laterally displaced in relation to the belt 4 centerline and the opening 8b is laterally displaced in relation to the rail 31 centerline.

The design of the suction cups 5, 5', 5" means that the tracked vehicle 100 can move over an uneven surface or a surface that curves, even if the frame construction 1 of the tracked vehicle 100 is rigid. The rail 31 can also be rigid. This is advantageous when the frame construction 1 constitutes a platform for tools such as brush tools 20 and for actuators 16.

In a variant of the invention, a further rail (not shown) is placed inside the inner part 29 of the belt 4, see fig. 2, and a suction device 50 is in fluid connection with the suction cups 5 on the outside of the inner part 29 of the belt 4, for generating negative pressure to the suction cups 5 in the same way as explained for the suction cups 5 on the outside of the outer part 30 of the belt. A tracked carriage 100 is thus produced which both on the underside and on the top have suction cups 5 which can stick to a surface 28.

The belt 4 is of the full belt type. By solid belt is meant a belt which forms a continuous external surface and is without continuous slits across the longitudinal direction of the belt. A belt of the type of articulated belt or chain belt will not work with the invention, as an articulated belt will have gaps between two successive links. Fluid will be able to flow through the slits and thus it is not possible to create a negative pressure in the suction cups 5, 5', 5" as described above.

When the suction cups 5, 5', 5" are suctioned to the surface 28, and the tracked vehicle 100 is thus attached to the surface 28, the tracked vehicle 100 can be exposed to forces from waves, tools or

other, which can cause the frame construction 1 of the tracked carriage 100 to move towards and from the surface 28. A movement of the tracked carriage 100 from the surface 28 will be able to lift the belt 4 clear of the rail 31, 31', 31" so that fluid will be able to flow in freely between the belt 4 and the rail 31, 31', 31" in the sealing area 36 and there will no longer be negative pressure in

the suction cups 5, 5', 5". Movement of the tracked carriage 100 from the surface 28 causes the guide ribs 61, 63 to abut against the internal guide lips 33, which will stop the movement.

The guide 6 for the necks 5b, 5b', 5b" of the suction cups 5, 5', 5", which is shown in the figures with the guide ribs 61, 63, is located on the outside of the belts 4, as seen from the belt carriage 100. The belts 4 are thus guided stably in its longitudinal direction, and the belts 4 are not subjected to twisting to a particular extent by a lateral load on the tracked vehicle 100. In the following, it will be described how the direction of travel of the tracked vehicle 100 can be changed.

Fig. 3 shows a turntable 11 in the central area of the tracked vehicle 100. The rotary table 11 is rotatably supported along its outer edge in brackets 12, so that it can be rotated in the horizontal plane in relation to the frame structure 1. The rotation is effected and controlled by a linear actuator 16, which can be electric, or it can be a hydraulic cylinder. The working length of the linear actuator 16 only allows for a limited rotation of the turntable 11. The rotation can alternatively be produced with a motor (not shown) fixed in the frame structure 1, and which rotates the turntable 11 via a chain, a belt or via a drive on the motor in engagement with a ring gear on the turntable 11 (not shown). The rotary table 11 can then be fully rotatable in relation to the frame 1.

The rotary table 11 comprises four holders 15 which each hold an actuator 13, see fig. 1. Each actuator 13 is provided with a suction cup 14, with suction surfaces facing the underside of the tracked vehicle 100. The suction cups 14 are connected via negative pressure hoses 39 to a suction device, not shown, which can produce a negative pressure that can be switched on and off and optionally be adjustable via means not shown, such as electric actuators, valves and switches. The suction cups 14 are shown arranged peripherally near the outer edge of the turntable 11.

In order to understand how the direction of travel of the tracked vehicle 100 can be changed, it is useful to imagine a plane formed by the suction surfaces of the suction cups 5 on the underside of the tracked vehicle 100. This plane is referred to in the following as the "fixing plane". When the suction cups 5 are suctioned to the surface 28, the attachment plane coincides with the surface 28. The actuators 13 can move the suction cups 14 from a position above the attachment plane, towards and past the attachment plane and back. The suction cups 14 can be movable collectively or individually. The number of holders 15, actuators 13 and suction cups 14 can be different from the four shown.

Based on the fact that the tracked vehicle 100 is suctioned to a surface, exemplified in the following with the surface 28, by means of the suction cups 5, the change of belt

the carriage's 100 direction of travel following steps:

- advancement of at least two of the rotary table's 11 suction cups 14 to the attachment plane, for placement against the surface 28; - generation of negative pressure between the rotary table 11 suction cups 14 and the surface 28, so that the rotary table 11 suction cups 14 are sucked firmly to the surface 28; - removal of negative pressure between the belt's 4 suction cups 5 and the surface 28, so that the belt's 4 suction cups 5 detach from the surface 28; - further advancement of the rotary table 11 suction cups 14, past the mounting plane, so that the belt 4 suction cups 5 and the frame construction 1 of the tracked carriage 100 are raised from the surface 28; - rotation of the rotary table 11 in relation to the frame structure 1, so that the frame structure 1 is rotated in relation to the surface 28; - retraction of the rotary table's 11 suction cups 14 to the attachment plane, so that the belt's 4 suction cups 5 are placed against the surface 28; - generation of negative pressure between the belt's 4 suction cups 5 and the surface 28, so that the belt's 4 suction cups 5 are sucked firmly to the surface 28; - removal of negative pressure between the turntable's 11 suction cups 14 and the surface 28, so that the turntable's 11 suction cups 14 detach from the surface 28; and - further withdrawal of the rotary table's 11 suction cups 14 from the mounting plane, so that the rotary table's 11 suction cups 14 are moved away from the surface 28.

The frame structure 1, which forms the main part of the tracked vehicle 100, has thus been rotated and given a new longitudinal direction, which is also the tracked vehicle 100's new direction of travel. If necessary, the above steps are repeated until the tracked vehicle 100 has obtained the desired direction of travel. Fig. 10 shows the tracked carriage 100 from below, and shows an opening 11b in the rotary table 11. The opening 11b has fixing possibilities, e.g. brackets with holes for bolts (not shown), for tools for carrying out work when the tracked carriage 100 is attached to the surface 28. The opening 11b can also be used as a freight compartment. Fig. 11 is a front view of the tracked vehicle 100 fitted with a plug tool on the rotary table 11. The plug tool is for installing and removing a plug 27 in a hull passage 28b. The plug tool comprises two or more linear actuators 25 mounted on the rotary table 11. The linear actuators 25 have piston rods which are fixed in a plug holder 25c, which comprises a locking device 25b for the plug 27. The locking device 25b can be a hydraulic actuator. The plug tool also comprises a linear actuator 26 with a piston rod with a hydraulic male coupling 26b for engagement with a corresponding hydraulic female coupling 27b in the plug 27, for applying hydraulic pressure. The linear actuators 25, 26 can be electric, or they can be hydraulic cylinders.

The plug 27 is locked to the plug holder 25c, and the hydraulic male coupling 26b is inserted into the hydraulic female coupling 27b, before launching the tracked vehicle 100. The tracked vehicle 100 is then, as previously explained, positioned by and secured to the surface 28 with the suction cups 5, with the plug 27 passing through the hull guide 28b. The linear actuators 25 and 26 are then pushed out, so that the plug 27 is displaced towards the surface 28 and into the hull passage 28b. Hydraulic pressure is then applied to the plug 27 through the hydraulic couplings 26b, 27b, which in a known manner causes a gasket in the plug 27 to expand against a sealing surface in the hull passage 28b, so that the plug 27 is locked. The actuator 26 is then pulled back, so that the male coupling 26b is pulled out of the female coupling 27b. The locking device 25b is released, so that the plug 27 is released from the plug holder 25c. The linear actuators 25 are then pulled back, so that the plug holder 25c is removed from the plug 27. The plug 27 is now installed in the hull passage 28b, and the tracked carriage 100 can be detached from the surface 28 and removed. The above can be repeated in the opposite order when the plug 27 is to be removed from the hull passage 28b. Instead of the linear actuator 26 with the hydraulic male coupling 26b, the plug tool can alternatively be equipped with a motor or actuator (not shown) to operate a mechanically operable plug.

The suction cups 5 are shown in the drawings as circular suction cups 5. The suction cups 5 can also have other geometries such as square or rectangular, as is known in the art.

It should be noted that all of the above embodiments illustrate the invention, but do not limit it, and those skilled in the art will be able to devise many alternative embodiments without departing from the scope of the dependent claims. In the requirements, reference numbers in parentheses should not be seen as limiting. The use of the verb "to comprise" and its various forms does not exclude the presence of elements or steps not mentioned in the claims. The indefinite articles "an", "ei" or "et" before an element do not exclude the presence of several such elements. The fact that certain features are listed in mutually different dependent claims does not indicate that a combination of these features cannot be advantageously used.

Claims (11)

1. Tracked trolley (100) designed to be used underwater, with an underside for placement against a surface (28), comprising: - at least two wheels (2) and a drive device (19) for operating at least one of the two wheels (2); - a belt (4) running around and between the wheels (2), where the belt (4) between the wheels (2) runs in an inner part (29) and an outer part (30), where an outer side of the belt (4) part (30) forms the underside of the undercarriage (100); - a rail (31, 31', 31") positioned inside an inside of the outer part (30) of the belt (4); - suction cups (5, 5', 5") on the outside of the belt (4) for placement against the surface (28 ); and - a suction device (50) in fluid connection with the suction cups (5, 5', 5") so that a negative pressure is produced in the suction cups (5, 5' 5") when the suction cups (5, 5', 5") on the outside of the outer part (30) of the belt (4) are placed against the surface (28), and the belt carriage ( 100) is thereby held firmly against the surface (28), characterized in that - each suction cup (5) is provided with a neck (5b, 5b', 5b"); - the neck (5b, 5b', 5b") is attached to the belt ( 4); - the neck (5b, 5b', 5b") comprises at least one slot (54); - an internal channel (32, 32', 32") extends through the neck (5b, 5b', 5b") and the belt ( 4); - a guide (6, 6') fixed in the tracked carriage (100) comprises at least one guide rib (61, 63; 65) positioned in the gap (54) when the suction cups (5, 5', 5") is on the outside of the outer part (30) of the belt (4); and - a fluid connection is formed by a vacuum pipe (10, 10', 10"), a vacuum chamber (8, 8', 8"; 38) and the internal channel (32, 32', 32") between the suction device (50) and the suction cup (5, 5', 5"). 2. Belt trolley (100) according to claim 1, where the guide (6) consists of two longitudinal guide ribs (61, 63) on opposite sides of the necks (5b, 5b', 5b) of the suction cups (5, 5', 5") ). 3. Tracked trolley (100) according to claim 1 or 2, where the guide (6, 6') is attached to the rail (31, 31', 31"). 4. Belt trolley (100) according to claim 1, where the neck (5b, 5b', 5b") of the suction cup (5, 5', 5") is provided with a circular groove (57); and a guide rib (65) is provided in its longitudinal direction with a longitudinal bead (67), where the bead (67) is positioned in the groove (57) when the suction cup (5, 5', 5") is on the outside of the belt (4) outer part (30). 5. Belt trolley (100) according to claim 1, where the suction cup (5, 5', 5") is attached to the belt (4) with a pipe (52) to a fastening block (5c) on the inside of the belt (4). 6. Belt trolley (100) according to claim 1, where the suction cup (5, 5', 5") is attached to the belt (4) with a through connection (35) to a fastening block (5c) on the inside of the belt (4). 7. Tracked carriage (100) according to one of the preceding claims, where the belt (4) lies mainly tightly sliding against the rail (31, 31', 31") in a sealing area (36). 8. Tracked vehicle (100) according to one of the preceding claims, where the rail (31, 31') has at least one negative pressure chamber (8, 8', 8") fluidly connected to the suction device (50) with the negative pressure pipe (10, 10', 10"), and the vacuum chamber (8, 8', 8") is fluidly connected to the internal channel (32, 32', 32") through a longitudinal opening (8b, 8b', 8b"). 9. Tracked vehicle (100) according to claim 8, where the rail (31') has two negative pressure chambers (8', 8") fluidly connected to each suction device (50) with each negative pressure tube (10), and the two negative pressure chambers (8 ', 8") are in fluid communication with various internal channels (32', 32"). 10. Tracked vehicle (100) according to claim 1, where the rail (31") has a recessed longitudinal middle part (37) which is open to the belt (4), and the recessed middle part (37) is fluidly connected to the suction device (50) with the vacuum tube (10), so that a vacuum chamber (38) is formed between the rail (31") and the belt (4), and the vacuum chamber (38) is fluidly connected to the internal channel (32). 11. A tracked vehicle (100) according to any one of the preceding claims, wherein the negative pressure chamber (8, 8', 8"; 38) is elongated.