GB2597520A - A new and improved motion device - Google Patents

Abstract

A motion device 1 having at least one gear 2 comprising an elongate main body 6 rotatable about its longitudinal axis and having a motion contact surface 9 on its outer surface. At least part of the elongate main body comprises a hollow internal region 4 located along the longitudinal axis of the gear. A shaft 21 extends from at least one motor 5, with at least a portion of the motor configured to be located within at least part of the hollow internal region of the main body of the gear. The motor shaft (21, fig 2b) and at least part of an internal portion of the main body of the gear are mechanically coupled such that in use direct or indirect rotation of the motor shaft by the motor provides rotation of the main body of the gear causing motion transfer of the device along the inspection surface via its motion contact surface.

Description

A new and improved Motion Device The invention is in the field of motion devices comprising a motor and gear assembly for use with inspection equipment for the inspection of the internal or external surface of a structure, in particular for use on pipes having a small diameter, elbows and complex layouts.

The use of robotic crawlers to carry out the inspection of pipework is a well-established practice in the field of Non-Destructive Testing (NDT) and remote visual inspection. The inspection activities relate to inspecting the exterior and the interior of pipes using mechanical crawler assemblies fitted with probes or cameras that travel along the pipework in order to provide information regarding the structural integrity of the same pipework. Retrieval activities can also be undertaken by these crawlers.

It is well known for these mechanical crawlers to be battery operated or they can alternatively be connected to an umbilical (comprising cables) providing the necessary connection to power the crawler. Typically such crawler assemblies rely upon a gear and motor assembly to provide movement of the mechanical crawler, most commonly providing linear motion on the surface to which they are applied.

The gear and motor assembly is usually comprised of a motor and a gear box connected mechanically to a gear system in mechanical communication with a moveable surface contact portion to create motion transfer of the device with respect to the surface to be inspected e.g. a wheel or track may be applied. The gears are configured to transform the rotational motion for the motor shaft into a linear motion meant to propel the crawler forward and/or backward along the surface to which it is applied.

The gear and motor system is commonly provided in series in order to provide a linear motion of the crawler along the surface it is positioned upon. By arranging the gear and motor assemblies in series a low cost and reliable assembly is realised and as such the gear and motor modules of crawlers are generally assembled in this way. However this makes them inherently long since the dimension of the crawler is dictated by the dimensional stacking of the gear and motor assembly components.

This series configuration provides a limitation on how small the mechanical crawler can be constructed in length and diameter, thereby limiting the range of pipework and tubes that can be inspected. For example, it is seldom that the pipework to be inspected is constructed only of straight pipes and typical networks are made of straights and bends of various angular turn e.g. 90 degrees, 45 degrees etc. This means that the length of the mechanical crawlers (and specifically the length of the gear and motor module that predominantly dictates their length) is critical for successful negotiation of a bend in pipe network. The pipe diameter inspection capability will also be affected by the width of the device Ultimately, the series arrangement provides a restriction on the usability and range of the crawler making it unsuitable for pipes with smaller diameters or complex profiles.

Currently, the NDT market is saturated with crawlers following the same gear and motor architecture (i.e. those arranged in series) and therefore only partially answering the real need from industry by offering inherently limited systems. The current market offering for the minimum diameter to be inspected for so called mini crawlers is at best 45mm and this is to be applied in the best case scenario of pipework i.e. straight pipe with no obstacles (like welds) or changes in geometry (like deformation of the pipe or bends). Such a limitation leaves structures partially unexplored and affects the overall structural integrity reliability and, by extension, the safety of plants such as refineries, nuclear power plants, water and gas network etc. There is therefore identified a need for a motion device with a new motor and gear assembly architecture that addresses the limitations currently encountered by modern day mechanical crawlers in order to increase inspection capability reliability and to reduce the amount of unknown safety factors arising from the inability to gather data in hard to reach areas such as small diameter pipes and complex pipe networks.

Accordingly, in a first aspect of the invention there is thus provided a motion device for use on a surface of a material to be inspected via Non Destructive Testing comprising: at least one gear comprising an elongate main body rotatable about its longitudinal axis and having a motion contact surface on its outer surface, at least part of the elongate main body comprising a hollow internal region located along the longitudinal axis of the gear; and at least one motor from which extends a shaft, at least a portion of the motor configured to be located within at least part of the hollow internal region of the main body of the gear, wherein the motor shaft and at least part of an internal portion of the main body of the gear are mechanically coupled such that in use direct or indirect rotation of the motor shaft by the motor provides rotation of the main body of the gear causing motion transfer of the device along the inspection surface via its motion contact surface. The motion contact surface is created by a helical thread located on the exterior of the gear.

Such an arrangement is more compact when compared to existing crawler devices currently used in Non Destructive Testing, enabling versatile negotiation of complex pipework structures, particularly those with small diameters. It is possible for the motion contact surface of the gear to be applied directly to the inspection surface and the thread of the gear will create a linear motion of the device with respect to the inspection surface.

The gear and the motor may be arranged coaxially. Any offset between the shaft with the linear axis of the gear would provide an unbalanced motion of the device. Therefore, the coaxial relationship provides a smooth motion of the gear and a vibration free device. For the avoidance of doubt, the motor shaft and gear may be mechanically coupled at the shaft level.

The motor may further comprise a gear box configured intermediate the motor and the shaft for providing indirect rotational motion of the shaft by the motor. This provides control of the RPM and torque of the device.

Preferably, the gear may comprise a worm screw. The thread of the worm screw is helical and as such rotation of the worm screw converts the rotational motion to linear motion of the device. Therefore, the motion transfer surface may comprise a helical threaded portion located on the outer surface of the worm screw gear.

S

The motion transfer surface may be mechanically coupled with at least one moveable surface contact element, a portion of which is, in use, located between the motion transfer surface and the inspection surface so as to convert the substantially rotational motion of the gear to a linear motion of the device. The motion transfer surface is configured to optimise the transfer of rotational motion of the gear to linear motion of the device.

The moveable surface contact element may comprise at least one track. Alternatively to a track, other motion transfer surfaces may be applied e.g. wheels, rollers or other known motion transfer surface in the art.

At least one track may be arranged to surround the worm screw gear and motor such that the motion contact element is engageable with an internal surface of the track and contacts the inspection surface with an external surface. This embodiment enables the worm screw to engage with the track at an internal region. The track is offset slightly to ensure that only one contact region is provided between the gear and the track.

The track comprises multiple track elements which may comprise apertures co-operable with a portion of the helical thread of the worm screw, so as to form co-operable teeth and apertures. Engagement of the teeth with the apertures maximises the transfer of the rotational motion to the linear motion.

Removable high friction pad elements may be fixed to the exterior surface of the track which come into contact with the inspection surface. This arrangement provides better traction of the device as it moves along the inspection surface. The pad elements may comprise rubber, polymer, silicone or another high friction material. The removable pad element may alternatively comprise a magnetic element for use on ferromagnetic inspection surfaces.

Multiple tracks may be configured to engage with a single worm screw. This enables a greater surface contact area on the inspection surface offering increased stability of the inspection assembly.

The multiple tracks may be arranged in parallel with respect to each other.

This enables the use of a generic track to increase the surface contact for a bigger inspection module, rather than applying tracks of varying width.

The multiple tracks may be configured to be angularly offset from each other This provides the movement in various planes of the device, which helps to negotiate bends and may provide additional traction in more confined pipe regions.

The motion device may further comprise a main housing having parallel side walls, the side walls comprising complimentary fixing means on their outer surface for connecting at least a first and second motion device in a side by side configuration. This offers a versatile modular arrangement to be implemented by the user whereby multiple motion modules may be snap fitted together. In use, such an arrangement once again offers more power to the movement of the device and eliminates the need to use a larger motor and gear assembly.

A connector module may be co-operable with the side walls fixing means so as to connect at least a first and second motion device in a parallel configuration such that their side walls are spaced apart. This configuration forms a buggy and the connector module may provide a support area for location of inspection means and/or a battery module. The spacing between the tracks offers more stability on movement of the inspection device across an inspection surface, but at a cost of device width.

The motion device may comprise a main housing having substantially parallel side walls, further comprising a first and second bracket having a U-shaped connection portion connected respectively to sides walls at adjacent ends of at least two motion devices, with a flexible guide portion configured to mechanically cooperate with apertures located in the first U-shaped bracket and the second U-shaped bracket. This provides an end to end or daisy chaining configuration of the motion device which maintain a small width of the device assembly and enables several motion devices to be implemented to increase 10 the power of the arrangement. The flexible guide is preferably provided by the cable or umbilical that is provided to provide mechanical and electrical communication to the modules of inspection assembly. The flexibility of the guide helps the device negotiate complex turns in the pipework.

The motor shaft may be integrally formed with the gear. This ensures efficient 15 transfer of rotational motion between the shaft and the gear.

The motor may be retrofittable within a hollow region of the main body of the gear. This offers the benefit of easily replacing components that have failed without having to change multiple parts of the assembly.

The location of the motor may provide additional internal support to the main body of the gear The motor becomes part of the main housing structure and eliminates the need for additional housing block parts and any excess weight that is provided by them. A smaller housing block is implemented to secure an end of the motor to keep it in a fixed position.

In an alternative embodiment of the invention there is provided an inspection assembly comprising at least one motion device of any preceding claim, further comprising at least one inspection module mechanically coupled in a direct or indirect configuration relative to the at least one motion device, so as to cause movement of the inspection module on movement of the motion device. An umbilical may be provided for attachment of the inspection module and the required number of motion devices. In this arrangement the inspection module and the motion device is indirectly mechanically coupled. Alternatively, in the buggy arrangement the inspection module may be located on the connector module of the buggy and as such is directly mechanically coupled. In both arrangements it is the motion device that drives the movement of the inspection module. Power modules may also be provided either as a separate module attached to the umbilical, or as a module applied to the connector module of the buggy. Therefore the relative mechanical coupling of the inspection module and at least one motion device causes the inspection module to be driven by the motion device. Driven means pulling, pushing or carrying of the inspection module.

In a further aspect of the invention there is provided a method of inspecting a material comprising, positioning a device on an inspection surface, the device comprising at least one gear comprising an elongate main body rotatable about its longitudinal axis, the at least part of the elongate main body comprising a hollow internal region located along the longitudinal axis of the gear; and comprising at least one motor from which extends a shaft, at least a portion of the motor configured to be located within at least part of the hollow internal region of the gear main body, the method further comprising mechanically coupling the shaft with an internal region of the gear so as to provide rotation of the main body of the gear upon rotation of the motor shaft by the motor, thereby causing motion transfer of the device along the inspection surface via a motion contact surface of the device Such an arrangement is more compact when compared to existing crawler devices currently used in Non Destructive Testing, enabling versatile negotiation of complex pipework structures, particularly those with small diameters. It is possible for the motion contact surface of the gear to be applied directly to the inspection surface and the thread of the gear will create a linear motion of the device with respect to the inspection surface.

The method may further comprise mechanically coupling a track to the motion contact surface, the track being located between the motion transfer surface and the inspection surface so as to convert the substantially rotational motion of the gear to a linear motion of the device. Thereby maximising the efficiency of transfer between rotational and linear motion.

The method may further comprise connecting at least two motion devices in a side by side configuration via co-operable fixing means located on their side walls prior to placing the device on the surface of the material to be inspected. The modular nature of the motion devices makes for a versatile apparatus for the user which enables the user to increase power, stability and compactness of the device as required for their specific needs. The adaptability of the motion device offers unprecedented advantages over existing devices which are usually designed for a specific use requirement.

The method may further comprise connecting the motion devices in an end to end configuration via at least one bracket co-operable with side walls of the motion devices prior to placing the device on the surface of the material to be inspected. This provides a buggy type configuration that can provide a standalone device without the need of an umbilical, and offers a complete wireless capability.

Whilst the invention has been hereinbefore described it extends to any inventive combination of the features set out above, or of the following description drawings or claims, but does not go broader than the independent claims on filed. For example, any features described in relation to any one aspect of the invention is understood to be disclosed also in relation to any other aspect of the invention.

The present invention will now be described, by way of example only, in which: Figure 1 shows a general isometric view of a motion device according to 15 an aspect of the invention; Figure 2A and 2B shows a front view of the motion device; Figure 3 shows a side by side modular configuration of a first and second motion device; Figure 4 shows a series arrangement of a first and a second motion device; Figure 5a shows the motion device of Figure 1 having a first and second track positioned side by side; Figure 5b shows the motion device of Figure one having a first and second motion module connected side by side via adjacent side walls of the respective devices; Figure 6 shows the motion device of Figure 1 having a first and second track positioned at an angle to each other; Figure 7 shows an alternative embodiment of the invention where the 5 gear is configured to engage with an external surface of the track; and Figure 8 shows an inspection assembly comprising the motion device of Figure 1.

In the figures like elements are denoted by like reference numerals. The skilled reader will appreciate that the number of optional features 10 present, will be driven by the user's requirements. Those requirements may include the weight of a part that the motion device is require to recover; the weight of the inspection equipment to be manoeuvred through the pipework, the diameter of the pipes to be inspected or the complexity of the pipe geometry may also define requirements of the equipment to be used, the user will likely be 15 minded to incorporate every optional feature, however one who has less of a requirement may scale back.

Common to all embodiments of the invention a user, who may for example be an NDT inspection engineer, wishes to inspect the internal surface of pipework regardless of its geometry.

The subject matter disclosed hereinafter is directed to a method of construction for mechanical motor modules used more specifically but not only in crawler systems in the field of non-destructive testing and remote visual inspections.

Figure 1 shows a motion device 1 comprising a worm screw gear 2 having a threaded outer surface 3 and configured to be rotatable about its longitudinal axis. The worm screw 2 has a hollow core 4 which houses a motor 5. This coaxial configuration of the gear 2 and motor 5 significantly saves space over the standard series gear and motor arrangements applied to NDT inspection detectors. The motor 5 and main body 6 of the gear 2 are mechanically coupled such that in use rotation of the motor 5 provides rotation of the main body 6 of the worm screw 2. Specifically, the motor 5 and the inner surface of the worm screw 7 are mechanically coupled at the shaft level. Therefore when the motor is in operation the rotational movement of the motor causes rotation of the worm screw about its longitudinal axis. A gearbox (not shown) is fitted inside the worm screw 2 to reduce the rpm generated by the motor and to increase the torque of the worm screw.

The outer surface of the worm screw 3 is mechanically co-operable with an inner surface 8 of a moveable track 9 for ensuring efficient transfer of the rotational motion of the worm screw 2 to a linear motion of the device 1 along the surface of the structure to be inspected.

A track 9 is configured around the worm screw 2 such that the thread of the worm screw 3 engages with an inner surface 8 of the track 9.

Specifically, the threads which act as gear teeth mate with apertures 10 located in the internal surface 8 of the track 9. The pitch of the teeth are configured to compliment the apertures 10 to ensure the appropriate mating of the teeth 3a with the track apertures 10 so as to enable the outer surface of the worm screw 3 and the inner surface 8 of the track 9 to reliably mesh when the track 9 is located between the device 1 contact surface and the worm screw 2. It is also important that the teeth 3a are sufficiently configured to ensure a smooth and friction limited release of the tooth 3a from the track aperture 10 as the track becomes offset from the contact region.

There is a trade-off between the friction of the engaged teeth 3a versus the required driving force to provide sufficient motion of the device 1 for the inspection application. In this embodiment, a maximum of 3 teeth 3a are received in respective apertures 10 of the track 9 at any one time However this value could be varied depending on the requirements of the user and the size of the device.

The track 9 is configured in a direction that is aligned with and substantially parallel to the longitudinal axis of the worm screw 2, and by design perpendicular to the direction of rotation of the worm screw 2. This results in a compact motion device that is versatile to the user and reduces the length and width of the device 1. It is worth noting that there will be a trade-off between the requirements of the inspection and the size of the motor 5 and worm screw 2, however this arrangement enable the optimisation of space for the given requirements in comparison to the standard series arrangement.

Figure 2a shows a front view of the motion device 1 and Figure 2b shows a cross section of the motion device 1 to better display the relationship between 20 the motor 5, the worm screw 2 and the main housing 11.

Figure 2a shows the side walls 12 of the outer housing 11 that define the guide edge 13 of the track. Bearings 14 are arranged along the guide edge 13 to minimise friction effects on the track 9. It also shows the tapered edge 15 of the side walls 12 that provides an internal volume for the worm screw and motor to extend into. The tapered side edges 15 also ensure that there is minimised contact of the outer housing 11 of the motion device 1 with the surface of the material/structure to be inspected.

A track 9 is made of a plurality of elements 16 engaging into each other in order to form a closed chain. The teeth receiving apertures 11 are equally spaced along the track 9. The track 9 is held into place in a guide 13 which is formed by the side edges 12 of the main housing 6 of the motion device 1.

The multi-elements 16 of the track 9 snap-fit together, but are releasable to enable shortening of the track 9 where required, or to replace damaged or worn elements 16. The outer contact surface 17 of the track 9 extends outwardly from the side edge 15 of the housing 6. Each track element 15 has a hollow region 18 and an aperture 19 for enabling a fixing means (not shown) to be passed through so as to secure a rubber pad 20 to the outer surface of the track element 17 to maximise frictional forces and encourage reliable movement of the motion device along the surface. The pad 20 can be replaced when it is worn, or indeed may permit the replacement of the pad for one having an alternative material providing an alternative desirable characteristic, for example, pads having magnetic properties can be used to aid the positioning and retention of the motion device 1 on a surface of a pipe possessing ferromagnetic properties.

In Figure 2b there is shown a shaft 21 extending from the motor 5 and connected to an internal region 7 of the main body of the worm screw 2. The motor 5 is fixed to a first housing block 22 located at a first end of the motion device 1 located within the housing 11 via a fixing member e.g. a screw. A second housing block 23 is located at the opposite end of the motion device 1 within the housing walls. The side walls 12 of the housing are joined together via the first and second housing blocks 22, 23. The combination of the first housing block 22, second housing block 23 and the side walls 12 of the housing form a cradle for the motor 5 and gear 2 assembly The end of the shaft 21 that is remote from the motor 5 is supported against the side edge of the second housing block 23. A bearing 24 is positioned intermediate the end of the shaft 21 and the side edge of the second housing block 23 to reduce the frictional effects and to maximise rotation of the shaft 21. Further bearings (not shown) are included about the shaft 21 to counter the axial and radial loads so as to further reduce friction and maximise the rotation of the worm screw 2 in use.

The track 9 is a removable portion that can be replaced with an alternative motion transfer element e.g. the track can be replaced by a rubber belt or wheels and roller may be applied if desired.

Any fixing means such as circlips, nuts, screws or bolts may be applied to fix the side walls 12 of the housing 11 to the first and second housing block 22, 23, and to fix the motor 5 to the first housing block 22. The motor acts to further support the components of the motion device 1 and become effectively part of the main housing 11 structure.

Figure 3 shows a pair of motion devices 1, 1' joined together in a parallel arrangement via their adjacent side walls by a connection module 25 to form a buggy Inspection equipment (not shown) may be applied to or attached to the connection module 25. The connection module 25 can be created in any desirable size depending on the diameter of the pipe to be inspected. Any number of motion devices 1 can be combined in this way, making for an extremely versatile arrangement.

Figure 4 shows a pair of motion devices 1, 1' configured in series and linked via two U-shaped brackets 26, 26' that are rotatably fixed to respective adjacent ends of the first and second motion device 1, 1'. A connecting flexible guide arm member 27 is located intermediate the two U-shaped brackets 26, 26' so as to join the motion devices 1, 1' together. As an example, the guide arm is an umbilical 28 comprising one or more flexible cables for connecting the modules of the inspection assembly together. In the wired configuration the umbilical 28 extends from the inspection assembly to the user control station. Daisy chaining of the motion devices in this way offers the ability to create a device having more power to drive the inspection equipment along the inspection surface whilst maintaining the width of the device. Any number of motion devices can be combined in this way, making for an extremely versatile arrangement. The number of motion devices 1 to be applied need only be limited by the desired length of the inspection assembly Figure 5a shows a combination of two tracks 9, 9' positioned next to each other and meshing on the same worm screw 2. Bearings (not shown) are provided between the two tracks 9, 9' to minimise any frictional effects at the side edges of the tracks. Alternatively the side edges of the tracks can be snap fitted together.

Alternatively 5b shows an embodiment where the side wall 12 of a first motion device 1 is attached to a side wall 12' of a second motion device 1'so as to create a parallel arrangement having a narrower width to that in Figure 3.

Such side walls 12, 12' have snap fit connectors to make the motion device assembly 1 a retrofittable product to provide versatility to the user. Alternatively, or on the other side walls, the side walls 12, 12' can be formed to include the branding or logo of the company or a display surface may be printed if preferred by the user. Any number of motion devices can be combined in this way, making for an extremely versatile arrangement.

Figure 6 demonstrates a motion device 1 having a single worm screw 2 and motor 5 assembly, but a first and second track 9, 9', where the first track 9 is positioned in an angular orientation that is offset from the second track 9' for example the first track 9 is arranged perpendicular to the second track 9'. Both the first track 9 and the second track 9' mesh with the same worm screw. This embodiment offers linear movement in two planes of the motion device if desired. A spacer (not shown) is positioned between the first track 9 and the second track 9' and may be formed as part of the main housing 11. Depending on the size of the track, further numbers of tracks arranged in other configurations may be implemented, making for an extremely versatile arrangement. Therefore there are provided multiple tracks 9 configured at an angular offset to each other engaging with the worm screw 2 in this way so as to offer differing linear movement capabilities suitable for use at bends of the pipe to be inspected.

Figure 7 shows that the gear 2 and motors arrangement need not be enclosed by the track 9 such that they are mechanically coupled with the internal surface 8 of the track 9 and the worm screw 2 may instead be located to one side of the track 9 such that the worm screw motion transfer surface 3 is mechanically coupled with the outer surface 17 of the track 9. The apertures 10 are therefore also provided on this outer surface 17. This embodiment provides a wider device, but still offers a limited length as desired by the user The inspection equipment to be applied is driven by the motion device 1 5 and may be located at different positions depending upon the embodiment utilised. For example a visible light camera may be applied to the connection module 25 of Figure 3. Alternatively if the embodiment of Figure 4 was used, the camera may be located on a separate inspection module configured on the umbilical 28. Indeed, the inspection equipment (which need not be in the visible 10 band and may instead operate in, for example, the infra-red part of the spectrum), may be carried behind or in front of the motion device 1 apparatus. Data collected may be transferred along the umbilical or may be stored on the inspection equipment and accessed on retrieval of the motion device 1 as desired.

Power is provided via the umbilical or power module driven by the motion device 1. The connection of these external power sources are applied to a portion of the main housing 11. Alternatively, batteries may be used as a power source and may be incorporated in a compartment located within or attached to the main housing 11. The size of the motion device 1 will impact where a battery module is utilised, hence the umbilical module or other external power module that is configured to trail the device is preferred for small and more complex pipe arrangements as shown in Figure 8.

The motion device 1 is a modular assembly that can be arranged in many different configurations and combinations offering reliable versatility to the user and ensuring optimised inspection for a variety of pipe diameters and network geometry. As shown in Figure 8, when configured for use, the inspection assembly 29 will comprise the motion device 1 configuration as required (which may include one or multiple devices in one or multiple of the above-mentioned configurations). A series of modules are then applied, for example there will be provided an inspection module, e.g. camera 30, the motion device configuration of choice 1, a battery module 31, transceiver 32 and microprocessor module 33, and any further modules deemed required for the particular inspection job.

Whilst it is possible to implement only a single motion device 1 configuration to cause push and pull of any inspection module, it is preferred to have further control of the inspection assembly by placing a motion device module 1, 1' either side of the inspection module to prevent kinking of the umbilical and to minimise motion jittering that could compromise the data acquisition In use the user places the device 1 of its preferred modular configuration having inspection equipment and an umbilical 28 onto the surface of the structure to be inspected. The user controls the motion of the motion device via a computational device (not shown) located at an inspection base (not shown) either on the site of the inspection, or at a remote site as desired. The user has a controller to direct the motion of the device 1 and the electrical signals are passed across the umbilical 28 along a cable to a microprocessor 33 that is located in a separate module and in electrical communication with the motor/s 5 of the modular device as applicable. When requested the motor 5 operates and causes the shaft 21 to rotate. Since the shaft is connected to an end of the worm screw, the worm screw also rotates. A bearing located between the end of the shaft and the second housing block receives the end of the shaft 21 so as to ensure that frictional forces are reduced and optimise the rotation of the worm screw 2.

The teeth 3a of the worm screw 2 mesh with complimentary apertures 10 of the track 9 so as to transfer rotational motion of the worm screw 2 to linear motion of the motion device 1 with respect to the inspection surface. The motion device 1 as a result is caused to move forwards along the inspection surface and the inspection equipment 29 that is being pulled by the device 1 as a load is directed towards the surface of the structure enabling data on the structural integrity of the material to be acquired.

If the desire is for the device 1 to move backwards, the user will send such a signal along the umbilical 28 that will cause the motor 5 to rotate in the other direction so as to cause the worm screw 2 to also be rotated in the other direction and to therefore cause backwards linear movement along the inspection surface.

The data may be transferred back to the user and assessed in real-time, or may be collected for processing and inspection at a later time. The user implements a camera to help identify a suitable pathway of the motion device.

The umbilical 28 is also configured to enable transfer of the image from the camera to the user and the user responds to the image to direct the motion of the motion device. The inspection continues until sufficient data is collected across the desired surface area of the pipe or other structure.

Various modifications to the principles described above would suggest themselves to the skilled person. For example, there may be no moveable surface contact element provided i.e. no track 9 and the outer surface of the worm screw 3 may be in direct contact with the surface of the material to be inspected creating linear motion transfer of the device with respect to the material via the helical thread. In this arrangement the worm screw 2 requires a rubber or other frictional contact surface layer to optimise the linear motion of this arrangement.

Alternatively, the end of the shaft 21 that is remote from the motor 5 is positioned within an indent (not shown) located in the second housing block which is configured to receive the shaft 21 and to keep it in position and includes a friction limiting device e.g. a ball bearing (not shown). The increase in the surface area of the shaft 21 in contact with the side walls of the indent increases frictional forces and is considered more lossy, even with the inclusion of bearings.

Instead of wired communication, the control signal may be wireless and the control module may therefore comprise a transceiver. However, in complex pipe networks, a wired configuration can be more reliable since signal is assured (wireless signal interference can be problematic).

Alternatively the track can be made of a single block of flexible material 20 such as polymer, rubber etc. shaped in order to mesh with the worm screw.

It is noted that a gearbox need not be utilised in the motor 5 and gear 2 assembly, but the benefits of maximising the worm screw rotation torque for a given RPM will no longer be realised.

The fixing means (not shown) may not be applied to combine the shaft 21 with an end of the worm screw 2. The shaft 21 and the worm screw 2 may be snap fitted together, or the cradle may be configured to cause a tight fit of the worm screw 2 onto the shaft 21 to cause the shaft 21 to drive the worm screw 2. Whilst the worm screw 2 could be moulded onto the shaft 21, it is more preferred to construct them as separate components and to connect them together to provide the desired drive effect.

In an alternative embodiment of the invention the inspection module 29 may be configured on the connector module 25 of the buggy arrangement as provided in the embodiment of Figure 3, along with a battery module 31, removing the need for an umbilical 28.

The above mentioned embodiments enable the motion device to be manufactured in a more compact form than currently available NDT crawlers on the market. The modular nature of the device makes it versatile for the user The compact nature of the motion device, which is achieved by the coaxially arranged motor and worm screw offers a shorter assembly providing the ability to negotiate a more complex pipe network and associated improvements in inspection reliability regarding the structural integrity assessment of the structure.

Claims (25)

1. CLAIMS1. A motion device for use on a surface of a material to be inspected via Non Destructive Testing comprising: at least one gear comprising an elongate main body rotatable about its longitudinal axis and haying a motion contact surface on its outer surface, at least part of the elongate main body comprising a hollow internal region located along the longitudinal axis of the gear; and at least one motor from which extends a shaft, at least a portion of the motor configured to be located within at least part of the hollow internal region of the main body of the gear, wherein the motor shaft and at least part of an internal portion of the main body of the gear are mechanically coupled such that in use direct or indirect rotation of the motor shaft by the motor provides rotation of the main body of the gear causing motion transfer of the device along the inspection surface via its motion contact surface.
2. 2. A motion device according to claim 1, wherein the gear and the motor are arranged coaxially.
3. 3 A motion device according to any preceding claim, the motor further comprising a gear box configured intermediate the motor and the shaft for providing indirect rotational motion of the shaft by the motor.
4. 4 A motion device according to any preceding claim, wherein the gear comprises a worm screw.
5. 5. A motion device according to claim 4, wherein the motion transfer surface comprises a helical threaded portion located on the outer surface of the worm screw gear
6. 6 A motion device according to any preceding claim, wherein the motion transfer surface is mechanically coupled with at least one moveable surface contact element, a portion of which is, in use, located between the motion transfer surface and the inspection surface so as to convert the substantially rotational motion of the gear to a linear motion of the device
7. 7. A motion device according to claim 6, wherein the moveable surface contact element comprises at least one track.
8. 8. A motion device, wherein the at least one track is arranged to surround the worm screw gear and motor such that the motion contact element is engageable with an internal surface of the track and contacts the inspection surface with an external surface.
9. 9. A motion device according to any of claims 7 or 8, wherein the track comprises multiple track elements comprising apertures co-operable with a portion of the helical thread of the worm screw, so as to form co-operable teeth and apertures.
10. 10.A motion device according to claims 7 to 9, wherein removable high friction pad elements are fixed to the exterior surface of the track which come into contact with the inspection surface.
11. 11.A motion device according to claims 7 to 10, wherein the removable pad element comprises a magnetic element.
12. 12.A motion device according to any of claims 7 to 11, wherein multiple tracks are configured to engage with a single worm screw.
13. 13.A motion device according to any of claims 7 to 12 wherein the multiple tracks are arranged in parallel with respect to each other.
14. 14.A motion device according to any of claims 7 to 12, wherein the multiple tracks are configured to be angularly offset from each other.
15. 15.A motion device according to any preceding claim, further comprising a main housing having parallel side walls, the side walls comprising complimentary fixing means on their outer surface for connecting at least a first and second motion device in a side by side configuration.
16. 16.A motion device according to claim 15, wherein a connector module is co-operable with the side walls fixing means so as to connect at least a first and second motion module in a parallel configuration such that their side walls are spaced apart.
17. 17 A motion device according to any preceding claim, further comprising a main housing having parallel side walls, further comprising a first and second bracket having U-shaped connection portion connected respectively to sides walls at adjacent ends of at least two motion devices, with a flexible guide portion configured to mechanically cooperate with apertures located in the first U-shaped bracket and the second U-shaped bracket.
18. 18.A motion device according to any preceding claim, wherein the motor shaft is integrally formed with the gear.
19. 19.A motion device according to any preceding claim, wherein the motor is retrofittable within a hollow region of the main body of the gear.
20. 20.A motion device according to any preceding claim, wherein the location of the motor provides additional internal support to the main body of the gear.
21. 21.An inspection assembly comprising at least one motion device of any preceding claim, further comprising at least one inspection module mechanically coupled in a direct or indirect configuration relative to the at least one motion device, so as to cause movement of the inspection module on movement of the motion device.
22. 22.A method of inspecting a material comprising, positioning a device on an inspection surface, the device comprising at least one gear comprising an elongate main body rotatable about its longitudinal axis, the at least part of the elongate main body comprising a hollow internal region located along the longitudinal axis of the gear; and comprising at least one motor from which extends a shaft, at least a portion of the motor configured to be located within at least part of the hollow internal region of the gear main body, the method further comprising mechanically coupling the shaft with an internal region of the gear so as to provide rotation of the main body of the gear upon rotation of the motor shaft by the motor, thereby causing motion transfer of the device along the inspection surface via a motion contact surface of the device.
23. 23.A method according to claim 22, further comprising mechanically coupling a track to the motion contact surface, the track being located between the motion transfer surface and the inspection surface so as to convert the substantially rotational motion of the gear to a linear motion of the device.
24. 24.A method according to claim 22 or claim 23, comprising connecting at least two motion devices in a side by side configuration via co-operable fixing means located on their side walls prior to placing the device on the surface of the material to be inspected.
25. 25.A method according to any of claims 22 to 24 comprising connecting the motion devices in an end to end configuration via at least one bracket co-operable with side walls of the motion devices prior to placing the device on the surface of the material to be inspected.