AU2018223009A1 - Roller retaining arrangement - Google Patents

Abstract

Abstract A cable trolley 12 for use in a cable festoon system 10 of a container crane. The cable trolley 12 includes a roller assembly 35, 36 for tracking along a track 16 of the container crane to facilitate movement of the cable trolley 12. The roller assembly 35, 36 includes a roller mounted to rotate, a guard being positioned about the roller so that when the cable trolley 12 is in use in a cable festoon system 10, the roller is prevented from escape from the cable trolley 12 upon detachment of the roller from the cable trolley 12." Figure 1 <filename> LC)O IrN co C.0o

Description

[0001] This application claims priority from Australian Provisional Application filed on 5 September 2017, the contents of which are to be taken as incorporated herein by this reference.

Technical Field [0002] The present invention relates to a roller retaining arrangement for retaining rollers that are used in cable festooning systems for cranes, in particular for container cranes that are used in ports or docks for loading and unloading containers to and from container ships.

Background of Invention [0003] The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the discussion was part of the common general knowledge as at the priority date of the application.

[0004] Container cranes are used at ports and wharves for loading and unloading containers from container ships. These are sometimes known as “quayside” cranes.

In general, container cranes employ a travelling hoist and trolley structure that includes a driver’s cabin and a hoist that includes a “spreader” for connection to shipping containers. The hoist can raise and lower the spreader to lift and lower each shipping container. In operation, the hoist structure travels along a cantilever structure to move between an extended position in which it overlies a container ship which is docked at the port or wharf for loading or unloading containers from the ship and a retracted position in which it overlies the port or wharf from which containers can be lifted for loading onto a container ship, or to where a container can be deposited after removal from the container ship. A support structure supports the cantilever structure above the port or wharf usually to a substantial height in the order of about 20m, although the height can vary and thus can be higher or lower.

[0005] The hoist and trolley structure has numerous electrical cables connected to it, to provide electrical power, and control and data connections to the hoist, spreader,

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2018223009 30 Aug 2018 and the driver’s cabin. The electrical cables must therefore be able to extend and retract depending on the position ofthe hoist on the cantilever structure. To facilitate this extension and retraction ofthe electrical cables, a cable festoon system is typically employed. These systems allow the cables to bunch up or gather together in loops in the retracted position of the hoist (known as the cables being “ambushed”) and also allow the cables to extend from the ambushed condition as the hoist moves towards the extended position.

[0006] To act in the above manner, cable festooning systems employ a plurality of festoon or cable trolleys or carriages (hereinafter “cable trolleys”) to which the electric cables are attached. The cable trolleys are aligned in series along a track ofthe cantilever structure (usually an I-beam) and a section of cable extends between adjacent cable trolleys. A typical cable festooning system applied to a quayside crane might employ about 17 cable trolleys. When the hoist is in the fully extended position, the cable trolleys are spaced apart to the maximum extent and the electric cables are in their maximum extension, forming more shallow loops between adjacent cable trolleys than in the retracted position ofthe hoist. To protect the electric cables from straightening completely and placing tensile load on the cables, cable festooning systems employ flexible connections between adjacent cable trolleys that are shorter than the loops of electric cable between the trolleys. This restricts the spacing between adjacent cable trolleys to an extent that the electric cables never straighten completely. The flexible connections can be steel-wire rope or chain or the like.

[0007] The cable trolleys are not normally driven themselves. Rather, the hoist is driven, and by a connection between the hoist and the closest cable trolley, the cable trolleys are pulled to extend and pushed to retract upon movement ofthe hoist. That is, the trolley closest adjacent the hoist is first dragged forward and away from the remaining trolleys as the hoist commences movement away from the retracted position and as the first trolley moves, second and third trolleys start to move and the movement continues with subsequent trolleys as the hoist moves further away from the retracted position. With this movement ofthe trolleys, the cable extending between the trolleys also shifts from a bunched up or gathered together condition toward an extended condition. Likewise, in reverse, as the hoist moves from the extended position to the retracted position, the hoist first engages and starts to push the trolley closest adjacent the hoist and that trolley moves towards and eventually

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2018223009 30 Aug 2018 engages the next cable trolley in line and so on until all of the cable trolleys are in the retracted position at which the spacing between them is at a minimum. Of course, the hoist does not always move fully between the extended and retracted positions and so smaller movements of the hoist can be made between those positions.

[0008] The cable trolleys include wheels or rollers (hereinafter “rollers”) and the cantilever structure includes beams or tracks along which the rollers roll. A typical beam or track is an I-beam having top and bottom flanges connected by a central web, whereby the web extends substantially vertically. The cable trolleys can include several rollers to track along different sections of the track and for example, in respect of an I-beam, three rollers can be provided on each side of the beam for tracking along 1) the lateral edge of the bottom flange (a side roller), 2) the upper or top surface of the bottom flange (the main or top roller) and 3) the underneath or bottom surface of the bottom flange (the anti-lift or bottom roller). The top rollers that track along the top surface of the bottom flange bear the weight of the trolley and the electric cable or cables it carries, while the side rollers keep the trolley centred on the beam and the bottom rollers form anti-lift rollers preventing or limiting the trolleys from lifting upwardly relative to the beam.

[0009] The rollers of the cable trolleys need to be robust to withstand the constant rolling motion and loads imposed on them as the hoist continually moves between and within the retracted and extended positions. Moreover, the environment in which the cable trolleys operate is usually an open marine environment subject to rain, wind and sun, and includes the corrosive effects of salt water. However, despite robust construction, cable trolleys can fail. This can present safety hazards to personnel and equipment below the cable trolley if failure is associated with the detachment of any of the components of the cable trolley that can then fall from height. One known form of failure, although rare, is the failure of a roller of a cable trolley. A roller can detach from the shaft on which it is supported and once this occurs, the roller or portion of roller can fall from the height of the cantilever structure creating a workplace safety issue for personnel or equipment below the container crane.

[0010] In addition, the side roller provided for tracking along the lateral edge of the bottom flange usually has a rolling surface that is wider than the width of the edge of the bottom flange along which the roller tracks. Over time, this can cause the surface

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2018223009 30 Aug 2018 of the roller to form a groove within which the edge of the bottom flange extends. This results in premature wear of the roller requiring early replacement.

[0011] The present invention has been developed in order to overcome or at least alleviate problems discussed above and associated with failure and wear of cable trolleys.

Summary of Invention [0012] The present invention provides a cable trolley for use in a cable festoon system of a container crane, the cable trolley including a roller assembly for tracking along a track of the container crane to facilitate movement of the cable trolley, the roller assembly including a roller mounted to rotate, a guard being positioned about the roller so that when the cable trolley is in use in a cable festoon system, the roller is prevented from escape from the cable trolley upon detachment of the roller from the cable trolley.

[0013] The present invention advantageously improves the safety of cable festoon systems by preventing rollers that have failed by detachment from a cable trolley from escaping from the cable trolley and falling from height to the ground below. The present invention can thus improve workplace safety for workers and equipment.

[0014] A guard of the invention prevents a roller from escaping from the cable trolley once it has otherwise detached from the cable trolley. The guard of the invention thus secures the roller to the cable trolley even though the roller is no longer connected to the cable trolley in the manner in which it was originally constructed.

That original construction would normally have the roller mounted on an axle, boss or bush or the like.

[0015] A guard of the invention can fully secure a roller of the roller assembly, so that the guard fully contains or surrounds the roller and there is no reliance on the existing structure of the cable trolley to assist the prevention of roller escape. Alternatively, where the cable trolley already includes a structure that prevents escape of the roller past certain sections of the cable trolley, the guard can secure the roller against escape past the sections of the cable trolley that remain available to the roller. For example, the surface on which the top roller tracks will present a barrier

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2018223009 30 Aug 2018 against escape of the roller past that surface. The guard would thus not need to prevent escape past that surface and so the guard can be restricted to preventing escape in directions or through pathways other than past the rolling surface of the top roller.

[0016] In some forms of the invention, the guard can be a single panel that prevents escape in one direction. In other forms of the invention, the guard can prevent escape in more than one direction, being two, three, four or more directions. In some forms of the invention, a roller can be contained by a guard only in the direction of travel of the cable trolley along the track of the container crane. In other forms of the invention, the guard can contain a roller against upward escape relative to the direction of travel of the cable trolley along the track, or downward escape. A guard can also contain a roller against escape laterally to the direction of travel of the cable trolley along the track.

[0017] The guard or guards of the invention can have any suitable shape and can be square, rectangular or irregular shape. The guards can be two dimensional or flat, or can be three dimensional. The guard or guards of the invention can define an internal cavity or space within which a roller or rollers can be accommodated. The internal cavity or space can be of any suitable configuration or shape to accommodate the roller or rollers within the cavity or space. The cavity or space likely will be of square or rectangular cross-section. The cavity might be defined completely by guard, or by a combination of the guard and the existing structure of the cable trolley.

[0018] The guard or guards of the invention can be made from metal sheet or plate, or other material that is sufficiently strong and durable, such as some plastic materials. Where metal sheet or plate is selected, the guard or guards can be stamped or pressed into shape.

[0019] The guard or guards can also be formed of wire or mesh, such as metal wire or mesh. Guards of this kind can be rigid, like metal sheet or plate, but might allow better visual observation of the roller or rollers contained or protected by the guard or guards.

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2018223009 30 Aug 2018 [0020] The cable trolley according to the invention can include a single roller that is secured by a guard, or the cable trolley can include a plurality of rollers but with only one ofthe rollers being secured by a guard. Alternatively, a guard can be provided that secures two or more rollers, or a plurality of guards can be provided to secure two or more rollers.

[0021] Where the cable trolley includes a plurality of rollers, the guard of the cable trolley could secure the roller of the cable trolley that is the roller that is subject to the most work of the plurality of rollers and as such is the roller that would be most likely to fail. That roller could be the top roller that bears the weight of the trolley and the cable it carries.

[0022] The guard or guards that secure the roller or rollers of the cable trolley can be positioned closely adjacent the roller or rollers, or they can be away from the roller or rollers. A close proximity of the guards to the rollers is preferred to provide immediate containment or capture of a failed roller, however, the invention also covers arrangements in which a failed roller is allow to fall away from its point of mounting to the cable trolley but to be caught or captured in or by a guard that is mounted to the cable trolley away from the immediate vicinity of where the roller is mounted. The guard could for example, have or be a receptacle into which a failed roller can be collected.

[0023] In most forms of cable festoon systems, the cable trolleys are applied to Ibeams and roll along the bottom flange ofthe I-beam. While cable festooning systems can employ beams of other cross-section or the cable trolley could roll along the top flange of the I-beam, this is not the typical arrangement. Also, because most cable trolleys of typical cable festoon systems are applied to I-beams, the cable trolleys tend to have a symmetrical arrangement of rollers on either side ofthe web of the I-beam so that the rollers track along the bottom flange of the I-beam on each side of the web. Accordingly, the roller assembly of most cable trolleys would include identical roller arrangements on either side ofthe web and so would typically include at least a pair of rollers that track along the upper surface of the bottom flange with the pair of rollers being spaced apart on either side of the web. Likewise, other rollers that are provided, such as for tracking along the bottom surface of the bottom flange or along the edge of the flange, can also be repeated on each side of the I-beam.

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Accordingly, where this discussion refers to rollers on one side of an I-beam, the invention covers cable trolleys in which the same arrangement of rollers is present on the opposite side as well.

[0024] In some forms of the invention, a guard is applied to the roller of the roller assembly that tracks along the upper surface of the bottom flange of the I-beam. That roller would typically be the roller that bears the major weight of the trolley and the cable or cables it carries. The guard that is applied to that roller can include end guard sections, end panels for example, and a side guard section, a side panel for example, that are arranged in a U-configuration. The guard can be applied to the cable trolley to face front and rear rolling surfaces of the roller as well as an outer facing side surface. The guard can optionally, but preferably also include a top guard section, a top panel for example, that extends over the top surface of the roller. This form of guard can combine with the web and bottom flange of the I-beam to create a square or rectangular interior space within which the roller is accommodated. In this manner, the guard and the web and bottom flange of the I-beam enclose, contain, trap or otherwise restrain the roller in the event that the roller detaches from its mounting to the cable trolley. The guard sections can be panels as described above or they can be otherwise formed, such as from wire mesh.

[0025] The panels that form the guard described above can be of any suitable form and can include openings for viewing the roller within the guard. One or more of the panels can include openings. These openings can be provided for inspection of the roller or rollers as required during maintenance of the cable trolley that occurs from time to time. Where the panels are formed from wire mesh, the openings between the wire will provide for inspection of the rollers.

[0026] Where the guards are formed by panels, these can have any suitable form, and can be fabricated from metal sheet or plate for example. The panels could alternatively be plastic, or mesh, or could be metal bar. The construction of the panels is therefore not critical provided the panels satisfy the criteria to prevent the roller or rollers from escape from the cable trolley upon detachment of the roller from the cable trolley.

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2018223009 30 Aug 2018 [0027] As indicated above, in some forms of the invention, only one roller is subject to restraint by a guard. This can be justified by historical failure characteristics of cable trolleys, whereby the roller that is most likely or prone to fail is the one that is protected by a suitable guard.

[0028] However, in other forms of the invention, the restraint is applied to other or all of the rollers of the roller assembly of the cable trolley. In some forms of cable trolley, a side roller of the above described kind is provided to track along a lateral or side edge of the bottom flange of the I-beam. That form of side roller has the disadvantage that the rolling surface of the roller is usually wider than the width of the edge of the bottom flange along which the roller tracks and so the rolling surface can groove over time. In accordance with one form of the invention, a side roller is provided which is positioned to roll or track against a surface of the web of the I-beam rather than the lateral or side edge of the bottom flange of the I-beam. Advantageously, the surface of the web over which the roller will roll or track is greater than the width of the rolling surface of the roller. Accordingly, the rolling surface of the roller will not groove and so the life of the roller should be greater.

[0029] Moreover, by shifting the position of the side roller from the lateral edge of the bottom flange to the web gives the side roller closer proximity to the top roller and in some forms of the invention, the top and side rollers can be positioned adjacent each other (albeit with axes of rotation substantially perpendicular to each other depending on whether the I-beam is a taper flange beam or a parallel flange beam) and so allows a guard that is provided for positioning about the top roller to be configured also to be positioned about the side roller. In this form of the invention, the guard can again include end panels and a side panel that are arranged in a Uconfiguration, but the size of the guard is such as to enclose or contain each of the top and side rollers. The guard can optionally, but preferably, include a top panel that extends over the top surface or upper surfaces of each of the top and side rollers.

This form of guard can also combine with the web and bottom flange of the I-beam to create a square or rectangular interior space within which the two rollers are accommodated. In this manner, the guard and the web and bottom flange of the Ibeam enclose, contain, trap or otherwise restrain the two rollers in the event that one or both of the rollers detach from the cable trolley.

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2018223009 30 Aug 2018 [0030] A guard according to the invention can be provided as a single piece component and can be fabricated from sheet metal, such as by pressing or stamping. The single piece can include the end and side panels and where provided, a top panel. The single piece can include openings as required and features for attachment of the guard to the structure of the cable trolley.

[0031] A guard according to the invention need only have sufficient structure to prevent the roller from escape from the cable trolley upon detachment of the roller. It follows that the guard can be relatively open or fully closed, or somewhere in between, as long as the restraining effect required of the guard is satisfied. The guard does not need to have great strength but should nevertheless be robust and wear resistant. Stainless steel is the preferred material given the marine environment in which cable festooning systems ordinarily operate.

[0032] Where a bottom roller is provided and a guard is employed to prevent the bottom roller from escape from the cable trolley upon detachment of the bottom roller from the cable trolley, the guard for the bottom roller can be separate to the guard for the top roller and/or the side roller. In some forms of the invention, the structure of the cable trolley below the I-beam can already provide some restraint against escape of the bottom roller. Accordingly, the guard for the bottom roller might only need to prevent escape in certain directions. For example, the guard might only need to extend across the opposite rolling surfaces of the roller and not above, beneath or across the front and rear sides of the roller. In other forms of the invention, the guard might extend more completely about the roller and might include protection above, beneath or across the front and rear sides of the roller.

[0033] The guard for the bottom roller can be U-shaped. The base of the U-shape can fix to the existing structure and the upstanding sides of the U-shape can extend to overlie the opposite rolling surfaces of the roller. Alternatively, separate guard sections can be attached to the existing structure with each guard section being positioned to overlie a respective rolling surface of the roller. In this arrangement, the areas that the guard does not protect against escape would already be protected by the existing structure of the cable trolley. Thus, the bottom roller might be prevented from escape downwardly by components of the cable trolley such as by the bolts that connect components of the cable trolley together or by spacers that the bolts extend

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2018223009 30 Aug 2018 through. In this respect, the roller assembly can be connected to the body of the cable trolley via bolts that extend through spacers in order to space the roller assembly from the cable trolley body and to create a space for the rollers of the roller assembly. Thus, the bottom guard is not itself required to fully surround or fully contain the bottom roller where existing paths of escape of the bottom roller are already precluded by components of the cable trolley itself. This also applies to the guard or guards that are applied to the other roller or rollers of the roller assembly.

Brief Description of Drawings [0034] The present invention will now be described with reference to the figures of the accompanying drawings that illustrate particular preferred embodiments of the present invention, in which:

[0035] Figure 1 is a perspective view of a single cable trolley according to the invention applied to an I-beam of a cable festooning system.

[0036] Figure 1 a is a cross-sectional view of the single cable trolley of Figure 1.

[0037] Figure 2 is an end view of a cable trolley applied to an I-beam of a cable festooning system.

[0038] Figures 3 and 4 are rear and front views of a roller assembly for use in the cable trolley of Figure 1.

Detailed Description [0039] Figure 1 is a perspective view of a single cable trolley according to the invention applied to an I-beam of a cable festooning system 10. Figure 1a is a crosssectional view of the single cable trolley of Figure 1. The I-beam is a taper flange beam, although could equally be a parallel flange beam.

[0040] The portion of the cable festoon system 10 includes an I-beam 11 and a cable trolley 12. The cable trolley 12 includes a part circular or curved saddle 13 over which a pair of clamps 14 extends. In use, electric cables extend over the upper surface of the saddle 13 and are clamped to the surface by the clamps 14. The clamps include a rubber engagement element 15 in order not to damage the electric cables. The saddle 13 extends symmetrically to either side of the I-beam 11.

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2018223009 30 Aug 2018 [0041] The cable trolley 12 further includes a roller assembly for tracking along the bottom flange 16 of the I-beam 11 and it is the case that each of the opposite surfaces 17 and 18 of the bottom flange 16, on either side of the web 19, are engaged by the roller assembly. The cable trolley 12 is thus symmetrical about the web 19 and so the components that are seen in Figure 1 on one side of the web 19 are repeated in symmetrical relationship on the other side of the web 19 but are not visible in Figure 1. To illustrate this, Figure 2 is an end view of a trolley which has the same general shape and configuration of the cable trolley 12 of Figure 1. Figure 2 illustrates an existing cable trolley and does not include guards of the kind that will be described later herein for securing failed rollers. In Figure 2, a taper flange I-beam 25 is shown in part (sectioned through the centre web 26 and thus not showing the top flange), and the cable trolley 27 includes, symmetrically about the centre line through the web 26, top rollers 28, side rollers 29 and bottom rollers 30. The cable trolley 27 extends below the bottom rollers 30 to a curved saddle 31 above which are positioned cable clamps 32. The saddle 31 extends equally to either side of the web 26 and the cable clamps 32 are applied to the saddle 31 on each side of the web 26. The cable trolley 12 of Figure 1 has this same general symmetrical construction, although it differs as discussed below.

[0042] Returning to Figure 1, roller assemblies of a different kind to that shown in Figure 2 are employed in the cable trolley 12. In Figure 1, a pair of leading and trailing roller assemblies 35 and 36 is shown, although the designation of leading and trailing is arbitrary, given that the cable trolley 12 moves in each direction along the length of the I-beam 11. Thus, the cable trolley 12 could move in direction A to extend electric cables that it supports, as well as in the opposite direction B to retract those cables.

[0043] Each of the roller assemblies 35 and 36 is connected to a central structure 37 of the cable trolley 12 to which the saddle 13 is also connected. In Figure 1, the roller assemblies 35 and 36 are bolted to the cable trolley body or structure 37 by a plurality of bolts 38. The bolts 38 extend to roller assemblies on the opposite side of the I-beam 11.

[0044] Each of the roller assemblies 35 and 36 is identical to the other. However, the roller assemblies that are provided on the opposite side of the web 19 to track

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2018223009 30 Aug 2018 along the flange surface 18 are mirror images of the roller assemblies 35 and 36 rather than being identical.

[0045] Figure 3 is a perspective and isolated view of a roller assembly 40 according to the invention, and shows an inside view of the assembly 40. Figure 4 is an outer or opposite view of the same roller assembly 40. The roller assembly 40 is configured for tracking along the flange surface 18 of the I-beam 11. It will be evident from Figure 4, that the roller assembly 40 is the mirror image of the roller assemblies 35 and 36 of Figure 1. In addition, two of the roller assemblies 40 would be provided on the opposite side of the web 19 to track along the flange surface 18 and these assemblies 40 would be positioned directly opposite to the respective roller assemblies 35 and 36. Advantageously, Figures 3 and 4 show the mirror image construction of the roller assembly 40 compared to the roller assemblies 35 and 36.

[0046] The roller assembly 40 includes three rollers comprising a top roller 41, a side roller 42 and a bottom roller 43. The top roller 41 would roll along the flange 18 of the I-beam 11 and would support, along with the other top rollers of the cable trolley 12, a significant portion of the weight of the cable trolley 12 and the cables the trolley 12 supports.

[0047] The side roller 42 engages against the facing surface of the web 19 of the I-beam 11 and is intended to ensure that the cable trolley 12 tracks straight along the beam 11. Thus, where there is slight lateral movement of the cable trolley 12 relative to the I-beam 11, the side roller 42 engages the web 19 to maintain the correct orientation of the trolley 12. The side roller 42 rotates about a substantially horizontal axis.

[0048] The bottom roller 43 is an anti-lift roller that tracks against the underneath surface of the flange 16 but is only intended to engage the underneath surface of the flange 16 upon lifting movement of the cable trolley 12 relative to the I-beam 11. It is thus intended that the bottom roller 43 does not engage the flange 16 very often, but does so when the trolley is subjected to uplift forces, such as can be created during start-up of hoist movement (when the cable trolleys might jerk into movement) or when trolleys collide with each other, such as when the trolleys move to the ambushed position.

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2018223009 30 Aug 2018 [0049] With reference to Figure 2, the rollers 28 to 30 are positioned substantially the same as the rollers 41 to 43 of Figures 3 and 4. However, if any of the rollers 28 to 30 were to fail, such as to disengage from the axles on which they are mounted, each of the rollers would be free to escape from the cable trolley and to fall through the height ofthe cable trolley to the ground below. As explained earlier, this presents obvious workplace safety issues.

[0050] Accordingly, the roller assembly 40 of Figures 3 and 4 includes guards which are positioned about the rollers 41 to 43 so that in the event that any of those rollers were to fail and to detach from the roller assembly, the rollers would be prevented from escape and rather, would be restrained within the guards and the structure of the cable trolley 12.

[0051] The guards that are provided in Figures 3 and 4 (and Figure 1); include a top guard 45 and a bottom guard 46. The top guard 45 comprises a side panel 47 and a pair of end panels 48. The top guard 45 further includes a top panel 49. A further inside panel 51 extends from the side panel 48 substantially parallel to the side panel 47 to a position to overlie an opposite side of the roller 41 .The top guard 45 is stamped or pressed from sheet metal and includes a plurality of openings 50 which enable viewing of each of the top and side rollers 41 and 42. This is also evident from Figure 1.

[0052] The top guard 45 is bolted to a side leg plate or a roller support plate 55 (hereinafter roller support plate 55) via bolts 56. The support plate 55 is shown in Figure 1 as being bolted to the structure 37 ofthe cable trolley 12 via bolts 38. The bolts 38 extend through tubular spacers 61 to space the support plate 55 away from the structure 37 to achieve the correct running position ofthe rollers 41 and 42 on the I-beam 11. The plate 55 also supports axles 57 and 65 about which the rollers 41 and 43 are mounted and rotate.

[0053] The top guard 45 serves to completely contain each of the top and side rollers 41 and 42. In the event that either of those rollers were to fail and to detach from the axles on which they rotate, the top guard 45 in combination with other structural components ofthe cable trolley 12 and the I-beam 11, would prevent complete escape ofthe rollers 41 or 42 from the cable trolley 12. The rollers, having

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2018223009 30 Aug 2018 failed, would be retained within the top guard 45 and would remain in that position until such time as maintenance personnel discovered that failure had occurred and took steps to repair the failure. In that respect, maintenance personnel could access the bolts 56 that secure the top guard 45 to the roller support plate 55 and once those bolts 56 are removed, both the top guard 45 and the failed roller can also be removed. The failed roller can be replaced followed by replacement of the top guard 45 and the cable trolley 12 would then resume normal operation. Advantageously, the failed roller would be removed by qualified maintenance personnel and without risk of escaping from the cable trolley 12 and falling uncontrolled to the ground below.

[0054] To ensure that the bolts 56 do not come loose, bolt heads include openings through which a security tie-wire 54 passes.

[0055] With reference to Figures -1 and 3, complete containment of the rollers 41 and 42 is achieved by the top guard 45 as illustrated, in combination with the upper surface 18 of the flange 16 of the I-beam 11 and the facing surface of the web 19. With reference to the top roller 41, if that roller were to detach from its axle 57 (see Figure 4) the roller 41 would be contained within the guard 45 by the side panels 47 and 51, one of the end panels 48 and the top panel 49, in combination with the surface 17 of the flange 16 and the web 19. In addition, the roller mount 58 presents an abutment edge 59 which also serves to restrict the free movement of the roller 41 in the event that it became detached from the axle 57. Each of these panels and surfaces combine to prevent escape of the roller 41 upon failure.

[0056] Likewise, the roller 42 is contained by the side panel 47, the adjacent end panel 48, the top panel 49, the roller mount 58, the facing surface of the web 19 and the other roller 41.

[0057] It will be evident that the roller assembly 40 as shown in Figures 3 and 4 has the side roller 42 positioned differently to the side roller 29 of the arrangement of Figure 2. In Figure 2, the side roller 29 is positioned to engage against a facing edge of the flange 60 of the I-beam 25, so that the side roller 29 is at the bottom end of the top roller 28. In this arrangement, only a portion of the rolling surface of the side rollers 29 engages the facing edge of the flange 60 and this arrangement can promote grooving in the surface of the side rollers 29. However, in the form of the

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2018223009 30 Aug 2018 invention illustrated, the side rollers 42 engage against the web 19 and the full rolling surface of the side rollers 42 have that engagement. Accordingly, the side rollers 42 are subject to a more likely even wear and would not be subject to the same grooving effect as the side rollers 29.

[0058] A further advantage of the arrangement of Figures 1, 3 and 4, is that the guard 45 which is applied to the top and side rollers 41 and 42 is a single guard that accommodates the two rollers. Such a guard would be more difficult to fabricate (although it could be done) for the arrangement of the top and side rollers of Figure 2.

[0059] The bottom guard 46 includes side panels 62 and 63 that extend from attachment panel 64. The bottom guard 46 is U-shaped, but the base section 64 is not used for containment of the bottom roller 43 but rather, is used to attach the guard 46 to the support plate 55. As is evident from Figure 4, the attachment panel 64 facilitates attachment of the bottom guard 46 to the support plate 55 via the bolt 65 that forms the axle for the bottom roller 43.

[0060] With reference to Figure 1, the bolts 38 extend through the support plate 55 and into the structure 37 of the cable trolley 12. These bolts 38 extend fully across the structure 37 and into the roller assemblies located on the opposite side of the web

19. The bolts pass through the spacers 61 on either side of the structure 37 to properly space the plates 55 from the structure 37. Thus, the spacers 61 held by the bolts 38 form retaining bars below the bottom roller 43. Likewise, the flange 16 that overlies the bottom roller 43 forms a retaining surface above the bottom roller 43. It follows that the only remaining retention that is required of the bottom guard 46, is to prevent escape of the roller 43 in the direction of travel of the cable trolley 12, and as is shown, the side panels 62 and 63 provide that retention.

[0061] It will be evident from the discussion above, that with the top and bottom guards 45 and 46 applied to the roller assembly 40, that the rollers 41 to 43 are fully contained against escape from the cable trolley 12. Moreover, the rollers 41 to 43 remain visible to operational or maintenance personnel and so failure of one of the rollers will be evident on a visual inspection. Moreover, each of the guards 45 and 46 is easily removed by bolt removal for replacement of a failed roller.

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2018223009 30 Aug 2018 [0062] Still further, the invention covers the option to retrofit the guards 45 and 46 to existing cable trolleys and for example, in relation to Figure 2, the bottom guard 46 can be installed to the existing support plate of the Figure 2 arrangement by removing the bolt that supports the bottom roller 30 and installing the guard onto the bolt.

Clearly the top guard is not applicable to the Figure 2 assembly given the different respective positions of the side rollers 29 and 42. Nevertheless, the invention covers retrofitting of suitably configured guards to existing cable trolleys where the configuration of the rollers differs from that shown in Figures 1, 3 and 4.

[0063] While three rollers have been shown in each of the figures, the invention covers arrangements whereby only a top roller is provided, or where a top roller and one or both of the side and bottom rollers are provided. Further rollers could be provided in a roller assembly and likewise, suitable guards could be fabricated to suit roller assemblies having four or more rollers.

[0064] The festoon system 10 illustrated in Figure 1 is of course one example of such a system and the cable trolley 12 is just one example of the kind of trolley that can be employed with an I-beam of a cable festooning system. Cable trolleys of different configurations can be covered by the present invention, as can arrangements that are employed with different forms of beams.

[0065] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope of the present invention.

[0066] Where the terms comprise, comprises, comprised or comprising are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other feature, integer, step, component or group thereof.

Claims (21)

1. The claims defining the invention are as follows

   1. A cable trolley for use in a cable festoon system of a container crane, the cable trolley including a roller assembly for tracking along a track of the container crane to facilitate movement of the cable trolley, the roller assembly including a roller mounted to rotate, a guard being positioned about the roller so that when the cable trolley is in use in a cable festoon system, the roller is prevented from escape from the cable trolley upon detachment of the roller from the cable trolley.
2. 2. A cable trolley according to claim 1, the guard being arranged to fully contain or surround the roller.
3. 3. A cable trolley according to claim 1, the guard being arranged to partially contain or surround the roller.
4. 4. A cable trolley according to claim 3, the cable trolley including a structure to prevent escape of the roller past certain sections of the cable trolley and the guard preventing escape of the roller past sections of the cable trolley that do not prevent escape of the roller.
5. 5. A cable trolley according to claim 4, the structure of the cable trolley that prevents escape of the roller including the track of the container crane on which the cable trolley tracks.
6. 6. A cable trolley according to any one of claims 1 to 5, the guard preventing escape of the roller in a single direction.
7. 7. A cable trolley according to claim 6, the single direction being the direction of travel of the cable trolley along the track of the container crane.
8. 8. A cable trolley according to any one of claims 1 to 5, the guard preventing escape of the roller in more than one direction, being two, three, four or more directions.
9. 9. A cable trolley according to claim 8, the guard preventing escape of the roller upwardly or downwardly relative to the direction of travel of the cable trolley.

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10. 10. A cable trolley according to claim 8 or 9, the guard preventing escape ofthe roller laterally to the direction of travel ofthe cable trolley along the track.
11. 11. A cable trolley according to any one of claims 1 to 10, the guard defining an internal cavity or space within which the roller is accommodated.
12. 12. A cable trolley according to claim 11, the internal cavity or space being of square or rectangular cross-section.
13. 13. A cable trolley according to any one of claims 1 to 12, the roller assembly including a pair of rollers mounted to rotate and the guard being positioned about the pair of rollers so that when the cable trolley is in use in a cable festoon system, the rollers are prevented from escape from the cable trolley upon detachment of the roller from the cable trolley.
14. 14. A cable trolley according to any one of claims 1 to 12, the roller assembly including a pair of rollers mounted to rotate and a first guard being positioned about one ofthe pair of rollers and a second guard being positioned about the other of the pair of rollers, the first and second guards being operable to prevent escape of the pair of rollers from the cable trolley upon detachment of one or both of the pair of rollers from the cable trolley.
15. 15. A cable trolley according to any one of claims 1 to 14, the container crane including an I-beam having a top flange, a bottom flange and a web extending substantially vertically between the top and bottom flanges, the track ofthe container crane being the bottom flange and roller assembly including a pair of top rollers for tracking along an upper facing surface of the bottom flange on either side ofthe web, a guard being positioned about each top roller.
16. 16. A cable trolley according to claim 15, the guard positioned about each top roller including end guard sections to face front and rear rolling surfaces ofthe top roller and a side guard section to face an outer facing side surface of the top roller.
17. 17. A cable trolley according to claim 16, the guard further including a top guard section that extends over the top rolling surface of the roller.

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18. 18. A cable trolley according to any one of claims 15 to 17, further including a pair of side rollers for tracking along each of opposite surfaces of the web and each of the guards that are positioned about each top roller, extending to be positioned about each side roller.
19. 19. A cable trolley according to any one of claims 15 to 18, further including a pair of bottom rollers for tracking along a downward facing surface of the bottom flange on either side of the web, a guard being positioned about each bottom roller.
20. 20. A cable trolley according to any one of claims 1 to 19, the guard or guards being formed as panels or by wire mesh.
21. 21. A cable trolley according to any one of claims 1 to 20, the guard or guards including openings for inspection of the roller or rollers about which the guards extend.