TECHNICAL FIELD

[0001] The present invention relates to an apparatus for cleaning, maintaining and inspecting of building structures.

[0002] The invention has been devised particularly, although not necessarily solely, in relation to platform assemblies for cleaning, maintaining and inspecting support columns such as legs of oil platform assemblies.

BACKGROUND ART

[0003] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0004] Building structures and oil platform assemblies require periodical inspection to determine if the components have been damaged due to, for example, exposure to the environment. Cleaning of the areas to be inspected may first be required to provide a surface which is in a suitable condition for the chosen inspection technique.

[0005] As an example, the columns which support oil platform assemblies require periodical inspection with associated cleaning. This is particularly true for columns of offshore platform assemblies. The columns of offshore platform assemblies, due to being immersed in seawater, attract debris as well as marine life. Typically, debris attaches itself to the surface of the column. Also, the marine life tends to grow on the outer surface of the columns. Moreover, the support columns must be periodicall inspected in order to detect any damage to the actual support column. This is particularly true due to the harsh environment that the support columns of offshore platform assemblies are exposed to. In view of this it is essential that the outer surface of each support column be periodically cleaned to remove the debris as well as the marine life to allow periodical inspection. [0006] Currently the cleaning and inspecting of the support columns are conducted by locating platforms at particular positions of the support columns. These conventional platforms are designed for a single purpose. This purpose may be cleaning of the exterior surface, or alternatively, the platform may be designed only to incorporate inspections tools. Moreover, installation of the platforms is typically a cumbersome procedure. This is particularly true due to the relatively heavy weight of the platform. Also, the heavy weight of the platform makes the maneuvering of the platform, during the cleaning or inspection processes, cumbersome and slow.

[0007] It is against this background that the present invention has been developed. SUMMARY OF INVENTION

[0008] According to a first aspect of the invention there is provided a platform assembly for carrying and applying at least one tool onto a surface, the platform assembly comprising a guide rail system adapted to receive a tool provision incorporating the at least one tool for applying the tool onto the surface, the guide rail system being adapted to be moved along at (east one direction relative to the surface.

[0009] The guide rail system may comprise at least one carriage for engaging the surface and a support means for supporting the tool provision relative to the surface,

[0010] Preferably the tool provision is in the form of a cradle.

[0011] Preferably, the cradle is adapted to be slidably mounted on the support means to allow movement of the cradle in at least one alternate direction relative to the support means.

[0012] Preferably, the at least one carriage comprises retaining means for retaining the cradle relative to the surface.

[00 3] In one aspect of the invention the retaining means is provided by the radial stress exerted by the guide rail system.

[0014] In another aspect of the invention the retaining means comprises magnetic means.

[00 5] In another aspect of the invention the retaining means is provided by gravity. [0016] Preferably the at least one carriage is able to accommodate irregularities in the surface. The at least one carnage may have a shock absorbing means.

[0017] Preferably, the at least one carriage comprises at least one wheel for displacement of the at least one carriage along the at feast one direction relative to the surface.

[0018] The at least one wheel may incorporate the shock absorbing means. The shock absorbing means may be in the form of a plurality of bristles extending radially outward from the at least one wheel, whereby the distal end of the bristles are adapted to engage the surface. Preferably the plurality of bristles are adapted to deform or flex when the wheel engages an irregularity in the surface, such that the position of the rotational axis of the at least one wheel relative to the surface remains substantially unchanged when the at least one wheel encounters an irregularity.

[0019] Preferably, the at least one carriage further comprises a channel assembly adapted to rotatably support the at least one wheel.

[0020] In a particular arrangement, the channel assembly comprises at least one opening adapted to receive at least one portion of the at least one wheel. In this arrangement, the centre portion of each wheel is located within the channel assembly.

[0021] In a further arrangement the at least one wheel is rotatably supported on an external surface of the channel assembly.

[0022] Preferably, the channel assembly rotabaly supports a plurality of wheel sets. Each wheel set may comprise one or more wheels.

[0023] Preferably, a first wheel set is located at a first end of the channel assembly and a second wheel set is located at a second end of the channel assembly. Preferably, the first and second ends of the channel assembly are open ends.

[0024] In an alternative arrangement, the first and second ends of the channel assembly are closed ends.

Preferably, the carriage is adapted to be moved by rope means. The cable means may be manually operated or may be motor driven. The cable means may be operated remotely. The cable means allows for movement of the carriage relative to the surface. [0025] Preferably the channel assembly comprises a first channel and a second channel attached adjacent each other along their longitudinal extent. Preferably, the channels are attached to each other by securing means.

[0026] In one aspect of the invention the securing means is in the form of fastening pins traversing transversafly the channels.

[0027] In one aspect of the invention the securing means is in the form of a releasable locking mechanism. The locking mechanism may be operated external the channel assembly to allow for quick assembly and disassembly of the at least one channel assembly. The locking mechanism may comprise a fastening means to fasten the two channels relative to each other once locked together.

[0028] Preferably, the cable means comprises a first cable attached to the first end of the first channel and a second cable attached to the first end of the second channel.

[0029] In the arrangement, wherein the ends of the channels are open ends the first cable and second cable is attached to the fastening pins or to an opening in the top of each channel. In the alternative arrangement wherein the ends of the parallel flange channels are closed ends the first and second cable are attached to the ends of the parallel flange channels via eye bolts attached to the closed ends of the parallel flange channels.

[0030] Alternatively, the at least one wheel is driven by a motor to move the at least one carriage. Where there is more than one carriage movement of the carriages is substantially synchronised.

[0031] Preferably, the at least one wheel comprises a magnetic driven wheel. The magnetic wheel may assist in retaining the platform assembly relative to the surface,

[0032] Preferably, the platform assembly may be operated remotely.

[0033] Preferably, the at least one carriage is adapted to support the support means which is adapted to support the cradle.

[0034] Preferably, the guide rail system comprises a plurality of carriages.

[0035] Preferably, the support means of the guide rail system comprises at least one guide assembly. Preferably the at least one guide assembly is adapted to move between a normal position and an alternate position, such that the guide rail system may accommodate irregularities in the surface. When the alternate position is an extended position, such as when it is anticipated that the irregularities increase the surface dimension, then the normal position will be a contracted position. When the alternate position is a contracted position, such as when it is anticipated that the irregularities decrease the surface dimension, then the normal position will be an extended position. Irregularities may include marine growth on the surface, or surface deterioration such as may be caused by rust. Irregularities may also include changes in dimension of the surface being measured, as may be the case in a tapered column, or a ripple effect in the surface.

[0036] Preferably, the guide rail system further comprises a plurality of attachment assemblies for attaching the support means to the at least one carriage. Preferably each attachment assembly allows the guide rail system to accommodate irregularities in the surface.

[0037] Preferably one or more of the attachment assemblies are secured to each carriage. Preferably one or more of the attachment assemblies are used to attach the at least one guide assembly to each carriage.

[0038] Preferably, the guide rail system comprises a plurality of attachment assemblies. Preferably each attachment assembly provides a projection.

[0039] The at least one guide assembly comprises a plurality of guide rails which cooperate to provide a substantially continuous support surface when the at least one guide assembly is in its normal position. When the platform assembly is used to clean/inspect/repair a surface of a column, the at least one guide assembly will be in the form of a hoop.

[0040] Each guide rail may be in the form of an elongate element having a first end and a second end. The elongate element may be curved, straight or take another form depending upon the surface. Preferably each end has its own attachment assembly for securing the guide rail.

[0041] Preferably, the guide rail system comprises two guide assemblies.. [0042] In one aspect of the invention each end of each guide rail is pivotaliy secured to the projection of the attachment assembly, . Each attachment assembly may comprise at least one plate assembly adapted to be clampingly secured to the carriage.

[0043] In another aspect of the invention , the projection of each attachment assembly is adapted to be pivotaliy secured with respect to its respective carriage. Each attachment means may be in the form of a hinge member. Preferably, the hinge member provides the projection Preferably each end of each guide rail is pivotaliy secured to the projection of the attachment assembly.

[0044J In another aspect of the invention, the projection of each attachment assembly is pivotaliy secured to its respective carriage and is able to be angularly displaced relative to the pivot axis. In this arrangement the attachment assembly may be pivotaliy secured to the carriage, and may incorporate a biasing means to bias the at least one guide assembly in a normal position. Should the attachment means be required to pivot relative to the carriage, the biasing means will accommodate angular displacement of the guide rail relative to the carriage. This will improve the mobility of the platform assembly, particularly over irregularities in the surface.

[0045] Preferably, the projection spaces the at least one guide assembly from the surface .

[0046] Preferably, the at least one guide assembly is arranged relative to the at least one carriage such that the at least one tool is movable in a direction perpendicularly to the at least one direction of the at least one carriage. This will allow an operator to move the tool to any location on the surface.

[0047]

[0048] In one aspect of the invention, each guide rail is hollow with each end being open to slidingly receive a rod such that a rod extends between adjacent guide rails.

[0049] Preferably, each rod is exposed and forms part of the support surface when the guide assembly is in its expanded position.

[0050] Preferably, there is provided a spring member extending from one guide rail to its adjacent guide rail. In this arrangement, the spring member prevents the guide rail from separating with respect to each. Also, the spring member biases the guide rails to each other, returning the guide assembly to its normal condition once the irregularity has been passed.

[0051] Preferably, there are provided guide means for guidance of each rod during sliding of the rods along the second ends of the guide rails.

[0052] Preferably, each guide rail comprises a slotted hole adjacent each end and each end of each rod comprises a retaining spring pin adapted to slide along each of the slotted holes. In another aspect of the invention, a gap forms between adjacent guide rails as the guide assembly moves to its expanded position. In this arrangement the cradle is adapted to accommodate the gaps.

[0053] In an arrangement, there are provided a plurality of guide assemblies adapted to receive the cradle. Each guide assembly being in a spaced-apart relationship to the at least one carriage.

[0054] Preferably, a first guide assembly is attached adjacent the first end of each carriage and a second guide assemblies is attached adjacent the second end of each carriage.

[0055] Preferably, the first guide assembly and second guide assembly are parallel to each other.

[0056] Preferably the plurality of carriages are adapted to travel parallel with respect to each other.

[0057] Preferably, the plurality of carriages are interconnected via the first guide assembly and second guide assembly platform assembly.

[0058] Preferably, there are four carriages interconnected together by four curved guide rails defining a belt adapted to surround a structure such as a circular column. This arrangement is particular useful for the maintaining, cleaning and/or repairing support columns of building structures or columns of oil rigs.

[0059] Preferably the cradle is adapted to be releasably mounted on the guide rail system. The cradle may comprise at least one tool area adapted to receive a tool whereby the tool can interact with the surface.

[0060] Preferably, there are two tool areas, a first tool area and a second tool area. [0061] Preferably, the second tool area comprises adjustable shelving.

[0062] In an arrangement, the cradle comprises a first sliding roller assembly and a second sliding roller assembly, the first sliding roller assembly and the second sliding roller assembly being spaced apart with respect to each other.

[0063] Preferably, the first sliding roller assembly is adapted to be slidably attached to the first guide assembly and the second sliding roller assembly is adapted to be slidably attached to the second guide assembly.

[0064] Preferably each sliding roller assembly incorporates a plurality of retaining rollers to retain the cradle to the respective guide assembly.

[0065] Preferably at least one of the sliding roller assemblies incorporates a plurality of driven rollers to move the cradle along the guide surface provided by the guide assemblies. Preferably there are four or more driven rollers whereby at least three of the rollers remain in contact with the guide assembly. This ensures the cradle is supported even when the guide assembly is in its expanded condition.

[0066] Preferably the cradle incorporates a driving means, such as a motor, for moving the cradle. The motor may be operated remotely.

[0067] The driving means may drive the driven rollers.

[0068] Preferably at feast one of the sliding roller assemblies incorporates a plurality of locking rollers to retain the cradle to the respective guide assembly. The clamping rollers may be movable from a first condition in which the cradle may be placed on the guide rail system, and a second position in which the cradle is movably locked to the guide rail system.

[0069] Preferably, the first tool area is incorporated between the first sliding roller assembly and second sliding roller assembly.

[0070] According to a further aspect of the invention there is provided a platform assembly for carrying and applying at least one tool to inspect, clean and/or repair a surface, the platform assembly comprising: a guide rail system for providing a support means to a tool provision, the guide rail system being movable in at least one direction relative to the surface; the tool provision adapted to releasably support the at least one tool, the tool provision being movable relative to the guide rail system.

[0071] Preferably movement of the guide rail system translates to movement of the platform assembly in the at least one direction,

[0072] Preferably movement of the tool provision is in an alternate direction to that of the at least one direction.

[0073] The guide rail system may comprise a plurality of spaced a part carriages and at least one guide rail extending between the carriages.

[0074] Preferably the tool provision is adapted to be releasably secured to the at least one guide assembly.

[0075] Preferably the at least one guide rail is adapted to move between a first position and a second position, whereby the guide assembly accommodates irregularities in the surface. For instance, where the surface is the outer surface of a column of an oil platform assembly, the surface is subject to marine growth, particularly in the splash zone. In order for the platform assembly to operate over such a surface the at least one guide rail will need to accommodate the change in diameter of the column due to the irregular surface caused by the marine growth. In this scenario the guide assembly will move from the first condition (its normal position) to the second position (its extended position). When the platform assembly returns to the normal surface, the at least one guide assembly will return to the first position. In other arrangements the at least one guide assembly may move from the second condition (its normal position) to the first position (its contracted position).

[0076] According to a further aspect of the invention there is provided a platform assembly apparatus for carrying and applying at least one tool to inspect, clean and/or repair a surface, the platform assembly apparatus comprising a platform assembly as herein before described and a tool provision as herein before described.

[0077] According to a further aspect of the invention there is provided a platform assembly adapted to carry and applying at least one tool to inspect, clean and/or repair a surface, the platform assembly as herein before described. [0078] According to a further aspect of the invention there is provided a tool provision to carry and apply at least one tool to inspect, clean and/or repair a surface, the tool provision as herein before described, the tool provision adapted to co-operate with a platform assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof, This description is included solely for the purposes of exemplifying the present invention. It should not be

understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a support column of an oil rig ith a platform assembly according to a first embodiment of the invention located underneath a working platform.

Figure 2 is a side view of the support column incorporating the platform assembly of the first embodiment of the invention,;

Figure 3 is a side view of the section of the support column showing the platform assembly;

Figure 4 is a perspective view of the platform assembly according to the first embodiment ;

Figure 5 is an alternative perspective view of the platform assembly according to the first embodiment;

Figure 6 is a close up view of the platform assembly according to the first embodiment illustrating a tool provision attached to a guide assembly ;

Figure 7 is a close up view of a sliding roller assembly of the tool provision of the platform assembly according to the first embodiment; Figure 8 is a cross sectional top view of the support column of the oil rig incorporating the platform assembly according to the first embodiment;

Figure 9 is a close up perspective view of a portion of the carriage showing the support means of the platform assembly according to the first ;

Figure 10 is cross sectional top view of figure 8;

Figure 11 is a perspective view of a platform assembly in accordance with a second embodiment of the invention;

Figure 12 is a perspective view of a channel of a carriage of the platform assembly shown in figure 1 ;

Figure 13, is a close up view of a section of a carriage of the platform assembly shown in figure 11 illustrating hinge members adapted to receive a guide assembly.

Figure 14 is a perspective view of one of the hinge members shown in figure 3;

Figure 15 is a perspective view a guide rail of the guide assembly of the platform assembl shown in figure 11;

Figure 16 is a perspective view of a tool provision adapted to be retained relative to the platform assembly shown in figure 11;

Figure 17 is a perspective view of one of the roller assemblies of the tool provision shown in figure 11;

Figure 18 is a perspective view of two guide assemblies and associated attachment assemblies for use with a platform assembly according to a third embodiment of the invention;

Figure 19 is a rear perspective view of a carriage of a platform assembly according to a fourth embodiment of the invention;

Figure 20 is a front perspective view of the carriage shown in figure 19; Figure 21, 22 are rear perspective views of the two sided of the carriage shown in figure 19;

Figure 22 is a rear perspective view of the other side of the carriage shown in figure 19;

Figure 23 is a rear perspective view of a tool provision for use with a platform assembly according to a fifth embodiment of the invention; and

Figure 24 is a front perspective view of the tool provision shown in figure 23.

DESCRIPTION OF EMBODIMENTS

[0080] Figures 1 and 2 show respectively perspective and front view of a support column 10. The support column 10 may be for example a support column of an oil rig. The column 10 incorporates a support structure defining a working platform 12. The working platform 12 is of circular configuration and surrounds the support column 10. The working platform is adapted to receive personnel during maintenance and inspection of the column 10.

[0081] The column 10 further incorporates a platform assembly 14 in accordance with an embodiment of the invention. In the arrangement shown in the figures 1 and 2, the platform assembly 14 is located distal the working platform 12. However, as will be described with reference to method of operation of the platform assembly in accordance with the present embodiment of the invention, the platform assembly 4 is adapted to be moved along the longitudinal axis of the column 10. In an arrangement, the platform assembly 14 may comprise a guide rail system which provides a support means.

[0082] Figures 3 to 5 shows the platform assembly 14. The platform assembly 14 comprises a plurality of carriages 16. The carriages 16 are spaced apart with respect to each other and are arranged such the column 10 is surrounded by the carriages 16. The carriages 16 are connected to the support means in the form of an upper guide assembly 20a and a lower guide assembly 20b. In an arrangement, the carriages 16 may be in the form of modular skids. [0083]The platform assembly 14 is adapted to support a tool provision 22 The cradle 22 is adapted to be slidably attached to the guide assemblies 20. The fact that the cradle 22 is slidably attached to the guide assemblies 20 is particularly advantageous because it allows moving the cradle 22 around the circumference of the column 10. In arrangement, the cradle 22 comprises a tool carriage.

[0084] As mentioned before, the platform assembly 14 in accordance with the present embodiment of the invention is adapted to be moved along the length of the column 10. For this, there are provided cable means 24. The cable means 24 in the form of a cable 50 extend from the working surface 12 to the carriages 16 (see figures 1 or 2). This arrangement allows personnel located on the support surface 2 to move the platform assembly 14 along the length of the column 10.

[0085] Referring to figure 5, each of the carriage 16 comprises a pair of parallel flange channels 30. The parallel flange channels 30 are attached parallel to each other. The parallel flange channels are fastened together via fastening pins 32 and fastening plate assemblies 34.

[0086]There are three fastening pins 32a, 32b and 32c. An upper fastening pin 32a and a lower fastening pin 32c are located at each end of the carriage 16. Fastening pin 32b is located at the centre of the carriage 16. The fastening pins 32 traverse the parallel flange channels and comprise retaining means for keeping the parallel flange channels 30 together. The upper fastening pin 32a is adapted to fasten cable means 24.

[0087] Further, there are provided a pair of plate assemblies 34a and 34b. The plate assemblies 34 are mounted on the carriage 16 in a spaced apart relationship. The plate assembly 34a is located between the centre fastening pin 32b and the upper fastening pin 32a. The plate assembly 34b is located between the centre fastening pin 32b and the lower fastening pin 32c.

[0088] Referring to figure 6, each of the plate assemblies 34 comprises an inner plate 36 and an outer plate 38. The inner and outer plates 36 and 38 are arranged such that the parallel flange channels are sandwiched between the inner and outer plates 36 and 38. The inner plate 36 and the outer plate 38 are fastened together via fastening means 40. In the arrangement shown in the figures, the fastening means 40 comprise two pairs of screws 42a and 42b extending perpendicularly from the outer plate 38 towards the inner plate 36. Each pair of screws 42a and 42b traverse one of the parallel flange channels 30 for fastening of the screws 42 to the inner plate 36. This arrangement of fastening pins 32 and plate assemblies 34 keeps the parallel flange channels 30 parallel to each other during operation of the carriage 16.

[0089] As mentioned before, the carriages 16 are adapted to travel along the surface of the column 10. For this, each carriage 16 comprises two pair of wheels 48. Each pair of wheels 48 comprises a first wheel 48a and a second wheel 48b which are rotatably included within the parallel flange channel 30. The wheels 48 are located adjacent the ends of the carriages 16 between the fastening pins 32 and the plate assemblies 34.

[0090] In the arrangement shown in the figures, the carriages 16 are manually operated. This is accomplished via the cable means 24. For this, the cable 50 extends from each parallel flange channel 30 towards the working surface 12. Two ropes 50 are attached to the fastening pins 51 located at the end of the carriages 6 proximal to the working surface 12. In this arrangement, personnel located on the working surface 12 can manually raise or lower the platform assembly 14 by pulling at the ropes 50 or releasing the ropes 50.

[0091] As previously described, the platform assembly 14 is adapted to receive the cradle 22 which incorporates the cleaning and inspection tools. For this, the platform assembly 14 comprises guide assemblies 20. The guide assemblies 20 surround the periphery of the column 0 (see figure 8). As will be described below, the cradle 22 is adapted to be slidably mounted on the guide assemblies 20. This allows displacement of the cradle 22 around the periphery of the column 10.

[0092]The guide assemblies 20 are adapted to be attached to each of the carriage 16. Figure 9 shows a particular section of the guide assembly 20 attached to a carriage 16. In this embodiment attachment of the guide assembly 20 occurs via a pair of projections 52 which extend perpendicularly from the outer plate 38 of the fastening plate assembly 34.

[0093] In particular, the arrangement shown in the figures, the outer plate 38 is defined by two plate sections 38a and 38b. Each plate section 38a and 38b is attached to one the parallel flange channels 30 that define the carriage 16, For attaching the guide assembly 20 to the carriage 16, a projection 52 extend from one of the plate sections 38a and 38b. The projections 52 act to keep the guide assembly 20 spaced apart from the carriage 16.

[0094] As shown in figure 10, the projections 52 comprise free ends 54 adapted to receive the guide assembly 20. For this, openings are provided at each end 54. Further, reinforcement means are provided to provide support to the projections 52. The reinforcement means comprise right angled triangular sections attached to the plate section 38a and 38b and projections 52.

[0095]As mentioned before, the guide assemblies 20 are adapted to be attached to each of the carriages 16. Figure 10 shows a section of the guide assembly 20 attached to a carriage 16. As shown in figure 10, the guide assembly 20 comprises at least one guide assembly 60 attached to the free ends of the projections 52.

[0096]The at least one guide assembly 60 comprises a pair of guide rails 62 and 64. The guide rails 62 and 64 comprise each a first end 66 and a second end 67, The first ends 66 are adapted to be attached to the free ends of the projection 52. For this, the first ends 66 comprise slots 68 and an opening 70 (see figure 9). The guide rails 62, 64 are mounted onto the free ends of the projection 52 by sliding the free ends of the projection 52into the slots 68. The guide rails 62, 64 are fastened to the free ends of the projection 52via screw means which traverse the openings 56 of the free ends of the projection 52 and the openings 70 of the guide rails. In an arrangement the guide rails 62 and 64 may be pivotally attached to the projections 52.

[0097] Further, as mentioned above, the guide rails 62, 64 comprise second ends 67. The second ends 67 are adapted to slidably receive tubes 72. The fact that the tubes 72 are slidably received by the guide rails 62, 64 allows to selectively locate the tubes between an extended condition and a contracted condition with respect to the guide rails 62, 64. This arrangement is particularly useful because it allows varying the extension of the periphery of the guide assembly 20. As will be described with reference to the method of operation of the platform assembly 14 this is particularly useful because it allows to account for any irregularities that may be incorporated in the surface of the column 10. [0098] There are provided guide means 76 for guidance of each tube 72 as the tubes 72 slide along the longitudinal axis of the guide rails 62, 64 during displacement of the tubes 72 between contracted conditions and expanded conditions. The guide means 76 comprise slotted holes 78 adjacent each second end 67 of the guide rails 62, 64. Retaining spring pins 80 extends axially from the guide rails 62 at a location such that the pins 80 can slide along each of the slotted holes 78.

[0099] Also, there are provided means for limiting the extent at which the periphery of the guide assembly 20 may be expanded. These means return the tubes 72 to the contracted condition. The tubes 72 return to the contracted condition when the force which located the tubes 72 in expanded condition ceases. These means comprise a spring member 82. The spring member 82 extends from one end 84 of one of the tubes 72 to the other end 86 of the other tube 72.

[00100] As mentioned before, the guide assembly 20 is adapted to receive a cradle 22. The cradle 22 is adapted to be slidably mounted on the guide assembly 20 to allow displacement of the cradle 22 around the periphery of the column 10.

[00 01] Figure 5 shows the cradle 22 mounted on the upper and lower guide assembly 20a and 20b of the platform assembly 4.

[00 02] The cradle 22 comprises an upper carriage 90 and a lower carriage 92. A first tool area 94 is defined between the upper carriage 90 and the lower carriage 92. A second tool area 96 is defined by rods 98. The rods 98 are arranged such that the second tool area 96 is located adjacent the first tool area 94. The first and second tool areas 94 and 96 are adapted for releasably attaching the cleaning and/or inspection tools to the first and second tool areas. The fact that the cleaning and/or inspection tools are releasably attached to the tool areas 94 and 96 is particularly useful because it allows the cradle 22 to be used for several purposes.

[00103] The first tool area 94 is defined by a pair of horizontal plate sections 100 and a pair of vertical plate sections 102. The plate sections 100 and 102 are arranged to define the first tool area 94 adapted to receive the cleaning and/or inspection tools. The second tool area 96 is defined between the rods 98. For this there are provided shelving 99 slidably attached between the rods 98. The location of each shelf 99a and 99b of the shelving 99 may varied. This, for example, allows varying the distance that the shelfs 99a and 99b are separated with respect to each other. Varying the location of the shelfs 99a or 99b is advantageous because it allows adjusting the second ^" tool area 96 so that a variety of cleaning and/or inspections tool may be attached to the cradle 22.

[00104] As described above, the cradle 22 comprises the upper carriage 90 and the lower carriage 92 which allows moving the cradle around the columns 10. The upper carriage 90 and the lower carriage 92 are attached to the horizontal plate sections 100 such that the upper carriage 90 and lower carriage 92 are spaced apart with respect to each other. This arrangement allows mounting the upper carriage 90 to the upper guide assembly 20a and mounting the lower carriage 92 to the lower guide assembly 20b.

[00105] Referring now to figure 6, the upper and lower carriages 90 and 92 comprises two pairs of rollers assemblies 106 and 108. The roller assemblies 106 and 08 are mounted on the horizontal plate sections 00 in a spaced apart relationship with respect to each other. Each of the pair of roller assemblies 106 and 108 comprise a plate section 1 0 extending perpendicularly from the horizontal plate sections 0. An upper and a lower roller 12 and 114 are perpendicularly attached to each of the plate sections 110 space apart with respect to each other. The upper and lower rollers 112 and 14 are adapted to receive the guide rails 62 and 64 as well as the tubes 72. The cradle 22 is mounted on the guide assemblies 20a and 20b by locating the guide assemblies 20 between the rollers 2 and 114. In this manner, the cradle 22 is slldably mounted onto the guide assemblies 20.

[00106] Referring to figure 5, as was mentioned before, the platform assembly 12 may be displaced along the longitudinal axis of the column 0. This is accomplished via ropes 50 which extend from, the working platform assembly 10 to each of the carriages 16 of the platform assembly 14. The end of ropes 50 distal to the working surface 12 are attached to the fastening pins 32a of the carriage. Two ropes 50 are attached to each carriage 16.

[00107] Further, as previously described, the cradle 22 is slidably mounted on the guide assemblies 20. This allows the cradle 22 to travel around the periphery of the column 10. In an arrangement, the cradle 22 may be displaced manually by personnel located on the working platform assembly 12. For this, cable means (not shown) may be attached to the cradle 22 to allow the personnel to move the platform assembly 12 around the column 10. [00 08] Figures 11 to 17 show a platform assembly 200 according to a second embodiment of the invention. The platform assembly 200 according to the second embodiment is similar to the platform assembly 14 according to the first embodiment and similar reference numerals are used to identify similar parts.

[00109] The platform assembly 200 works substantially in a similar manner as the platform assembly 14 of the first embodiment of the invention. However, the platform assembly 200 comprises several variances with respect to the platform assembly 14.

[00 10] Referring to figure 11, the platform assembly 200 comprises a plurality of carriages 202. The carriages 202 are spaced apart with respect to each other and are arranged such the column 10 is surrounded by the carriages 202. The carnages 202 are joined together by an upper guide assembly 20a and a lower guide assembly 20b. The guide assemblies 20 are adapted -to slidably receive the cradle 22.

[001 1] Each of the carriages 202 comprises a pair of parallel flange channels 206. The parallel flange channels 206 are attached parallel to each other. The parallel flange channels 206 are fastened together via fastening pins 208. In the arrangement shown in the figures 11 to 17, the parallel flange channels comprise closed ends

[00112] There are two fastening pins 208, an upper fastening pin 208a and a lower fastening pin 208b respectively located at each end of the carriage 202. The fastening pins 208 traverse the parallel flange channels 206 for keeping the parallel flange channels 206 together.

[001 3] Each carriage 6 comprises two pair of wheels 48. Each pair of wheels 48 comprises a first wheel 48a and a second wheel 48b which are rotatably included within parallel flange channels 206. The wheels 48 are located adjacent the ends of the carnages 202 and rotatably attached to the fastening pins 208.

[001 4] The parallel flange channels 206 are adapted to receive the wheels 48 such that the centre portion of each wheel 48 is located within the parallel flange channels 206. For this, each of the parallel flange channels 206 comprises openings at each end of the parallel flange channels 206. Each of the openings are adapted to receive, a portion of the wheel 48.

[00115J As mentioned in relation to the first embodiment of the invention, the carriages 202 are manually operated. This is accomplished via the cable means 24. For this, the ropes 50 of the cable means 24 extend from parallel flange channels 206 towards the working surface 12. The ropes 50 are attached to eye bolts 210 located each end of the carriages 202.

[00116] As mentioned before, the carriages 202 are adapted to receive the guide assemblies 20. Attachment of the guide assembly 20 to the carriages 202 occurs via hinge members 212. The hinge members 212 act as means for attaching the carriage 202 to a support means, the support means comprising the guide assemblies 20.

[00 17] Referring back to figure 11, each guide assemblies 20 in accordance with the second embodiment of the invention comprises a plurality of rod sections 216 attached with respect to each other to define the guide assembly 20. Each end of the rod sections 216 is adapted to a hinge member 212. In this manner, the guide assemblies 20 are attached to the carriages 202.

[00 18] Figure 13 shows a particular section of the guide assembly 20a attached to a carriage 202. There are a pair of hinge members 212a and 212b attached to each end of each carriage 202.

[00119] For attaching the guide assembly 20a to the carriage 202, each hinge member 212 comprises a projection 224 having a free end 54 incorporating an opening 56. Each free end 54 is adapted to receive an end of a rod sections 216 . For this, an end of rod section 216 comprise a slot 218. The slotted end 218 is adapted to receive the free end 54 of the hinge member 212. Each slotted end 218 comprise an opening 220. The opening 220 in conjunction with the opening 56 of the free end 54 pivotally attach the slotted end 218 of each rod section 216 to the free end 54 of the hinge member 212.

[00120] The fact that the rod sections 218 of the guide assemblies 20 are attached to a hinge member 212 and that the attachment of the ends of rod sections 216 to the free ends 54 of the projections 224 is a pivotal attachment is particularly advantageous because this arrangement allows for varying the extension of the periphery of the guide assembly 20. As will be described with reference to the method of operation of the platform assembly 14, 202 this is particularly useful because it allows to account for any irregularities that may be incorporated in the surface of the column 10.

[00121] Referring now to figure 14, the hinge member 212 comprises a parallel flange channel section 222 and a projection 224. The projection 224 defines the free end 54 adapted to receive an end of the rod section 218 for attachment of the guide assembly 20 to the platform assembly 200.

[00122] The parallel flange channel section 222 comprises a plate section 226 and a pair of flange portions 228a and 228b extending perpendicularly from the plate section 226. The plate section 226 is adapted to be attached to the carriage 202 such that the flange portions 228a, 228b extend perpendicularly from the parallel flange channels 206.

[00123] A pair of screws 232 as well as an axle 230 are fastened between the flange portions 228. The axle 230 is adapted to pivotally receive the projection 224. In this manner, the projection 224 is pivotally attached to the parallel flange channel section 222. This arrangement defines the hinge member 212.

[00124] In the arrangement shown in the figures, the hinge member 212 is a springed hinge 212. For this, spring means 234 are operatively connected between the axle and the projection 224. The fact that the hinge member 212 is a springed hinge 212 is particularly advantageous because it allows the projection 224 to return to its original position. Typically, the projection 224 may be displaced from its original position due to forces that are applied to the guide assemblies 20 during operation of the platform assembly 202. Once these forces cease the projection 224 returns automatically to its original position. The return to the original position of the projection 224 is possible due to the Spring means 234 incorporated in the hinge member 212. As will be described with reference to the method of operation of the platform assembly 14, 202 this is particularly useful because it allows to account for any irregularities that may be incorporated in the surface of the column 0. [00125] As mentioned before, the guide assembly 20 is adapted to receive the cradle 22, The cradle 22 is adapted to be slidably mounted on the guide assembly 20 to allow displacement of the cradle 22 around the periphery of the column 10.

[00126] Figure 16 shows a tool provision in the form of a cradle 322 in accordance with the second embodiment of the invention- However, this cradle 322 may also be used in place of the cradle 22 in the first or other embodiments.

[00127] The cradle 322 comprises an upper carriage 90 and a lower carriage 92. A first tool area 94 is defined between the upper carriage 90 and the lower carriage 92, A second tool area 96 is defined by rods 98. The rods 98 are arranged such that the second tool area 96 is located adjacent the first tool area 94. The first and second tool areas 94 and 96 are adapted for releasably attaching the cleaning and/or inspection tools to the first and second tool areas. The fact that the cleaning and/or inspection tools are releasably attached to the tool areas 94 and 96 is particularly useful because it allows the cradle 322 to be used for several purposes,

[00128] The first tool area 94 is defined by a pair of horizontal plate sections 00 and a pair of vertical plate sections 102. The plate sections 100 and 102 are arranged to define the first tool area 94 adapted to receive the cleaning and/or inspection tools. The second tool area 96 is defined between the rods 98. For this there is provided a shelf 99 slidably attached between the rods 98. The location of the shelf 99 along the rods 98 may be varied. Varying the location of the shelf 99 is advantageous because it allows adjusting the second tool area 96 so that a variety of cleaning and/or inspections tool may be attached to the tool provision 322.

[00129] As described above, the cradle 322 comprises the upper carriage 90 and the lower carriage 92 which allows moving the cradle around the columns 10. The upper carriage 90 and the lower carriage 92 are attached to the horizontal plate sections 100 such that the upper carriage 90 and lower carriage 92 are spaced apart with respect to each other. This arrangement allows mounting the upper carriage 90 to the upper guide assembly 20a and mounting the lower carriage 92 to the lower guide assembly 20b.

[00130] Referring now to figures 16 and 17, the upper and lower carriages 90 and 92 comprises two pairs of rollers assemblies 106 and 108. The roller assemblies 106 and 108 are mounted on the horizontal plate sections 100 in a spaced apart relationship with respect to each other.

[00131] Referring now in particular to figure 17, each roller assembly 106, 108 comprise a plate section 110 extending perpendicularly from the horizontal plate sections 100. An upper and a lower parallel flange channel sections 236 are perpendicularly attached in a spaced apart relationship to the plate section 100, Further, an upper and a lower roller , 114 extend, respectively, between the parallel flange channel plate sections 236a and 236b.

[00132] In this arrangement, the rollers 112 and 114 are spaced apart with respect to each other to define a spacing adapted to receive a rod section 216 of the guide assemblies 20, This arrangement allows rod section 216 to locate between the rollers 112 and 114. A pair of helical springs 238 extend ^" between the upper parallel flange channel plate section 236a and the lower parallel flange channel plate section 236b. The springs 238 apply a force such that the upper and lower parallel flange channel plate sections 236a, 236b are brought together. The presence of the springs 238 is particularly useful because it allows for the change in the spacing between the rollers 112, 14.

[00133] In operation, initially the platform assembly 14, is assembled by personnel located on the working surface 12. After assembly of the platform assembly 14, the ropes 50 are attached to each of the carriages 16. Also, ropes (not shown) are attached to the cradle 22 to allow displacing the cradle 22 around the column 10 At this, stage the platform assembly 14 may be moved using the ropes 50 along the longitudinal axis of the column 10. Figures 1 and 2 show the column 10 incorporating the platform assembly 14 in accordance with an embodiment of the invention. The platform assembly 14 surrounds the column 10 at a location distal to the working surface 12. The personnel located on the working surface 12 may manually move the platform assembly 14 along the longitudinal axis of the column 10 by pulling or releasing the ropes 50. The cradle 22 can also be manually moved by the personnel located on the working platform 1 via the cable means attached to the cradle 22.

[00134] As mentioned above, the cradle 22 is adapted to move around the column 10. In this manner, the tools (not shown) incorporated in the cradle 22 are moved around the periphery of the column 10. Typically, the surface of the column 10 may incorporate irregularities such as protrusions extending outward from the surface or indentations extending into the surface. These irregularities may affect the travel path of the cradle 22. For example, a particular protrusion may obstruct passage of the tool as it moves adjacent the surface of the column 10. This obstruction may force the cradle 22 to separate itself from the surface of the column 10. This forces the diameter of the guide assemblies 20 to increase to account for the separation of the cradle 22 from the surface of the column. In accordance with the present embodiment of the invention, the fact the tubes 73 may be displaced between an extended condition and a contracted condition allows to increase or decrease the diameter of the guide assemblies to account for any irregularity found on the surface of the column 10.

[00135] Further, the cleaning and/or inspection equipment may be operated from the working surface 12. in an arrangement, wiring systems may be incorporated to operate from the working surface 12 the cleaning and/or inspection equipment.

[00136] Alternatively, the cleaning and/or inspection equipment may be operated remotely by the personnel located on the working surface 12. In this arrangement, the cleaning and/or inspection equipment may be operated wirelessly.

[00137] Figure 8 shows a first and second guide assembly which may be used in a third embodiment of the invention. They also may be used with previous embodiments. The guide assemblies comprise four guide rails 362,

[00138] Each guide assembly 320 provides a guide surface 331 and is shown with an attachment assembly 351 attached to each end 366, 367 of each guide rail 362. Each attachment assembly provides a projection 352 which is pivotally secured to a respective carriage (not shown) at pivot device 354 and is able to be angularly displaced relative to the pivot axis. In this arrangement each attachment assembly 351 is pivotally secured to the carriage, and incorporates a biasing means 355 to bias the at least one guide assembly in a normal position. Should the attachment means be required to pivot relative to the carriage, the biasing means will accommodate angular displacement of the guide rail relative to the carriage. This will improve the mobility of the platform assembly, particularly over irregularities in the surface.

[00139] Figure 19 to 22 shows a carriage 416 which may be used in a fourth embodiment of the invention. It may also be used with previous embodiments. [00140] The carriage 416 has a channel assembly comprises a first channel 406 and a second channel 407 attached adjacent each other along their longitudinal extent. Preferably, the channels are attached to each other by securing means which is in the form of a releasable locking mechanism 434. The locking mechanism is operatable external the channel assembly to allow for quick assembly and disassembly of the channel assembly. The locking mechanism comprises a fastening means 436 to fasten the two channels relative to each other once locked together.

[00141] Figures 23 to 24 shows a tool provision in the form of a cradle 522 which may be used in a fifth embodiment of the invention. It may also be used with previous embodiments.

[00142] The cradle 522 comprises a first sliding roller assembly 524 and a second sliding roller assembly 526. The first sliding roller assembly and the second sliding roller assembly being spaced apart with respect to each other.

[00143] The first sliding roller assembly 524 may be slidably attached to the first guide assembly and the second sliding roller assembly 526 may be slidably attached to the second guide assembly.

[00144] Each sliding roller assembly incorporates a plurality of retaining rollers 528 to retain the cradle to the respective guide assembly.

[00145] The first sliding roller assemblies 524 incorporates a plurality of driven rollers 530 to move the cradle along the guide surface provided by the guide assemblies (not shown). Preferably there are four or more driven rollers whereby at least three of the rollers remain in contact with the guide assembly. This ensures the cradle is supported even when the guide assembly is in its expanded condition.

[00146] Preferably the cradle incorporates a driving means, such as a motor 531, for moving the cradle. The motor may be operated remotely.

[00147] The driving means 531 may drive the driven rollers using belts (not shown) about pulley 532.

[00148] The second sliding roller assembly 526 incorporates a plurality of locking rollers 534 to retain the cradle to the guide assembly. The locking rollers are movable from a first condition in which the cradle may be placed on the guide rail system, and a second position in which the cradle is movably locked to the guide rail system, as shown in figures 22 and 23..

[00149] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention. The platform assembly in accordance with an embodiment of the invention is arranged such as to be adapted to surround a column such as a support column 10 of an offshore platform assembly. However, platform assemblies 14 in accordance with other embodiments of the invention may be arranged such to operate in conjunction with other type of structures. For example, a platform assembly in accordance with the present embodiment of the invention may be adapted to be used for cleaning and/or inspection of flat surfaces such as walls, roofs or windows. In this arrangement, the tubes 72 instead of being curved tubes are straight tubes. Further, another embodiment of the invention may incorporate a single carriage onto which at least one at least one guide assembly is attached to the carriage for receiving the cradle .

[00 50] Yet another embodiment of the invention, the platform assembly may be arranged such that the platform assembly does not surround the entirety of the column 10. For example, the platform assembly may be adapted to extend over a particular portion of the periphery of the column 10, In this arrangement the platform assembly is arc-shaped.

[00151] Further, it should be appreciated that the scope of the invention is not limited to the scope of the embodiments disclosed. By way of example, the platform assembly 14 may not necessarily be operated manually by the personnel located on the working surface. As an example, the carriages of the platform assembly 14 may incorporate machine driven rollers. This arrangement allows for the platform assembly to be operated remotely without the aid of cable means.

[00152] It is apparent that the above described embodiment of the invention provides an effective platform assembly for cleaning, inspection and maintenance of a building structure. The platform assemblies in accordance with the previously described embodiments of the invention are of modular construction. This is particular advantageous because it allows on-site assembly of the platform assembly. Further, the platform assemblies incorporate parts which are easy to obtain in the market place due to the fact these parts are off-shelf parts. [00153] The platform assembly also is adapted to be applied to different types or surfaces. This is particularly true because the configuration and dimension of the platform assembly may be easily varied by replacing the tubes 72 or rod sections 216. For example, the dimensions of the periphery of the platform assembly may be varied by using tubes or rod sections of different sizes. In this manner, the platform assembly may be fitted to numerous different types of columns 10. Also, the platform assembly is easily assembled for travelling along flat surfaces. This is accomplished by using straight tubes or straight rod sections 216 instead than curved tubes 72 or curved rod sections 216.

[00154] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.