AU2015246659A1

AU2015246659A1 - Mast assembly, mobile lighting plant including a mast assembly and methods of use thereof

Info

Publication number: AU2015246659A1
Application number: AU2015246659A
Authority: AU
Inventors: David John Nicholls
Original assignee: Dog Watch Lighting Pty Ltd
Current assignee: Dog Watch Lighting Pty Ltd
Priority date: 2014-04-18
Filing date: 2015-04-16
Publication date: 2016-10-06
Also published as: WO2015157825A1

Abstract

A mast assembly (12) for a mobile lighting plant (10), the mast assembly including a mast (14) pivotally coupled to a chassis (26) of the mobile lighting plant (10) so as to be moveable between a raised condition and a lowered condition; and a biasing means (16) configured to bias the mast toward the raised condition. A mobile lighting plant (10) is also disclosed including mast assembly (12) as are methods of use of the mast assembly (12) and the mobile lighting plant (10).

Description

Mast Assembly, Mobile Lighting Plant including a Mast Assembly and Methods of Use Thereof

Technical Field [001] The invention relates to a mast assembly, a mobile lighting plant including a mast assembly and methods of use thereof.

Background [002] It is often desirable to have mobile lighting on worksites such as building and construction sites and mine sites. Accordingly, there have been developed a number of mobile lighting arrangements that typically include a moveable base, such as a trailer, and a mast supporting a light extending from the moveable base. The moveable base typically includes a power supply such as batteries or a generator and the mast may be moveable between a raised condition and a lowered condition.

[003] In some lighting plants the mast may be articulated, for example, by a hinge joint located intermediate the mast. A hydraulic actuator may be operatively coupled to the mast to articulate the mast about the hinge joint between the raised and the lowered conditions. In other lighting plants, the mast may be telescopic and the telescopic sections may be extendable and retractable to raise and lower the mast.

[004] A problem with such masts of these lighting plants is that the mast is arranged to rest in a normally lowered condition. Accordingly, if the mast or components holding the mast are damaged or in correctly configured the mast may fall which may cause safety problems.

[005] Another problem with these lighting plants is that the masts are required to be lowered to transport the lighting plants. Yet another problem of these lighting plants relates to the robustness or longevity of the lighting plants such as the inclusion of hydraulic lines which may become damaged during operations and when raising and lowering the mast. Another problem with these lighting plants is that movement of the mast or lighting plant may damage the light carried by the mast.

[006] The invention disclosed herein seeks to overcome one or more of the above identified problems or at least provide a useful alternative.

Summary [007] In accordance with a first aspect there is provided, a mast assembly for a mobile lighting plant, the mast assembly including: a mast pivotally coupled to a chassis of the mobile lighting plant so as to be moveable between a raised condition and a lowered condition; and a biasing means configured to bias the mast toward the raised condition.

[008] In an aspect, the mast assembly includes an isolator assembly configured to inhibit the transmission of vibration between the chassis and a light head carried by the mast.

[009] In another aspect, the biasing means is provided in the form of a counter weight adapted to support the mast.

[0010] In yet another aspect, the isolator assembly incudes a mast isolator configured to provide damping between the counter weight and the mast.

[0011] In yet another aspect, the counter weight includes an aperture into which the mast is received, and wherein the mast isolator is at least partially fitted between the aperture and the mast.

[0012] In yet another aspect, the mast isolator is provided in the form of a resilient material and wherein the aperture is provided in the form a sleave dimensioned so as to allow the fitting of the resilient material between the mast and the sleave thereby allowing relative damped movement between the sleave and the mast.

[0013] In yet another aspect, the mast assembly includes a base adapted to support the mast, a lower portion of the base being supported by the chassis, and an upper portion of the base being adapted to pivotally support the counter weight so as to allow movement of the mast between the raised and lowered conditions.

[0014] In yet another aspect, the base includes spaced apart supports arranged to allow passage of the counter weight therebetween.

[0015] In yet another aspect, each of the spaced apart supports includes a bearing support arranged to pivotally couple with a shaft carried by the counter weight.

[0016] In yet another aspect, the isolator assembly includes at least one base isolator located between the base and the chassis of the mobile lighting plant.

[0017] In yet another aspect, the at least one base isolator is provided in the form of a plurality of base isolators adapted to provide damping in response to relative movement between the chassis and base in at least two directions including in the vertical and lateral directions.

[0018] In yet another aspect, the at least one base isolator is provided in the form of a plurality of base isolators including at least one vertical damper arranged to damp relative movement between the base and chassis in a vertical direction and at least one shear damper arranged to damp relative movement between the base and chassis in a lateral direction.

[0019] In yet another aspect, at least one friction reducing part is located between the base and the chassis.

[0020] In yet another aspect, the at least one friction reducing part is provided in the form of corresponding friction reducing bearing pads carried respectively by the base and the chassis.

[0021] In yet another aspect, the chassis is arranged to be movable in at least one of a forward and reverse direction, and wherein the mast assembly is adapted to allow the mast to move in a plane aligned with at least one of the forward and reverse directions.

[0022] In yet another aspect, the chassis is arranged to be movable in at least one of a forward and reverse direction, and wherein the counter weight of the mast assembly is adapted to allow limited relative movement of the mast in a plane aligned with the forward and reverse direction.

[0023] In yet another aspect, the mast assembly including an actuation mechanism adapted to rotate the light head supported by the mast.

[0024] In yet another aspect, the mast assembly includes an actuator accessible from a lower section of the mast and a coupling which extends internally of the mast between the actuator and the light head.

[0025] In yet another aspect, he coupling includes a conduit arranged to allow for passage of an electrical connection between the light head and a power supply located externally of the mast assembly.

[0026] In yet another aspect, the mast assembly further includes a second actuation mechanism adapted to adjust pitch a light of the light head.

[0027] In yet another aspect, the second actuation mechanism includes a second actuator accessible from the platform and a second coupling which extends externally of the mast between the second actuator and the light head.

[0028] In yet another aspect, the second coupling is a rod including a least two articulated sections which are moveable so as to allow rotation of the light head whilst the rod is coupled between the light head and the second actuator.

[0029] In accordance with a second aspect there is provided, a lighting plant including a mast assembly as defined above.

[0030] In an aspect, the plant includes a chassis supported by skids, and wherein the mast assembly is substantially centrally located on the chassis so as to provide a substantially even weight distribution.

[0031] In another aspect, the lighting plant further includes a power system including a controller, a generator and at least one battery, wherein the controller is configured to selectively operate the generator to charge the at least one battery so as to maintain power to a light of the light head.

[0032] In yet another aspect, the lighting plant includes at least one of a generator, an associated generator fuel tank and at least one battery are located toward opposing ends of the chassis relative to one another so as to provide a substantially even weight distribution.

[0033] In yet another aspect, a base of the mast assembly includes a compartment in which at least one battery is located.

[0034] In accordance with a third aspect there is provided, a method of operating a mast assembly for a mobile lighting plant, the method including the steps of: actuating a mast of the mast assembly to pivotally move the mast from a raised to a lowered condition in which a light head carried by the mast is accessible; and releasing the mast such that a biasing means of the mast assembly returns the mast to an ordinarily raised condition.

[0035] In accordance with a fourth aspect there is provided, a method of moving a lighting plant having a mast assembly including a pivotally moveable mast biased toward an ordinarily raised condition, the method including the steps of: bearing a vehicle on at least one of a forward and rear end of a chassis of the lighting plant so as to move the lighting plant in at least one of forward and rear direction, the mast being in the ordinarily raised condition with at least one isolator of the mast assembly operating so as to inhibit the transfer of vibration between the chassis and a mast head carried by the mast.

[0036] In accordance with a fifth aspect there is provided, a mast assembly for a mobile lighting plant, the mast assembly including a base pivotally supporting a mast, a light head moveably supported by the mast, a counter weight arranged to bias the mast into a normally raised condition, and an actuation mechanism adapted to rotate the light head relative to the mast.

[0037] In accordance with a sixth aspect there is provided, a mobile lighting plant including a mast assembly, the mast assembly including a mast pivotally coupled to a chassis of the mobile lighting plant so as to be moveable between a raised condition and a lowered condition; and a biasing means configured to bias the mast toward the raised condition.

Brief Description of the Figures [0038] The invention is described, by way of non-limiting example only, by reference to the accompanying figures, in which; [0039] Figure 1 is a perspective view illustrating a mobile lighting plant including a mast assembly in a raised condition; [0040] Figure 2 is a perspective view illustrating a mobile lighting plant including a mast assembly in a lowered condition; [0041] Figure 3 is a perspective view illustrating another example of the mobile lighting plant including a mast assembly in a raised condition; [0042] Figure 4 is a perspective view illustrating another example of the mobile lighting plant including a mast assembly in a lowered condition; [0043] Figure 5 is an exploded parts view illustrating the mobile lighting plant; [0044] Figure 6 is a perspective cutaway view illustrating parts of the mast assembly including a counter weight, a mast and a light head; [0045] Figure 7 is an exploded parts view illustrating parts of the mast assembly including the mast and the actuation arrangement; [0046] Figure 8 is a partial perspective view illustrating a lower portion of the mast assembly; [0047] Figure 9 is a partial sectional perspective view illustrating the lower portion of the mast assembly; [0048] Figure 10 is a side sectional view illustrating the lower portion of the mast assembly; [0049] Figure 11 is an exploded parts perspective view illustrating parts of the lighting head; [0050] Figure 12 is side sectional view illustrating a coupling between the lighting head and the mast; [0051] Figure 13 is a simplified schematic diagram illustrating a power system of the lighting plant; [0052] Figure 14 is a perspective view illustrating a further example of the mobile lighting plant including the mast assembly; [0053] Figure 15 is a perspective view illustrating the mast, light head and counter weight of the mast assembly; [0054] Figure 16 is a perspective view of the light head; [0055] Figure 17 is a perspective view of a section of the mast assembly including a spacer frame and wire guides; [0056] Figure 18 is a perspective view of the arrangement of the counter weight with an external side of the housing removed to show the internal configuration and coupling with the mast; [0057] Figure 19 is a top view illustrating the counter weight with the mast removed and hidden detail showing the coupling of a stub-shaft with the counter weight; [0058] Figure 20 is a sectional view illustrating an example of the counter weight having a cylindrical tube and locator for the mast; [0059] Figure 21 is a sectional view illustrating another example of the counter weight having a cylindrical tube which tapers toward the bottom for friction fitting with the mast; [0060] Figure 22 is an underside perspective view illustrating a base of the mast arrangement; [0061] Figure 23 is a topside perspective view illustrating the base of the mast arrangement with one of the supports removed to reveal the base plate; [0062] Figure 24 is a side sectional view illustrating the arrangement of a isolator assembly between the base and the chassis; [0063] Figure 25 is a partial side perspective view illustrating the coupling of the isolator assembly between the base and the chassis; and [0064] Figure 26 is a partial perspective view illustrating the chassis of the mobile plant to which the base of the mast arrangement is coupled.

Detailed Description [0065] Referring to Figures 1 and 2, there is shown a mobile lighting plant 10 including a mast arrangement or assembly 12 and a body 11 arranged to support the mast assembly 12. The mast assembly 12 includes a mast 14 pivotally coupled to the body 11 so as to be moveable between a raised condition, as shown in Figure 1, and a lowered condition as shown in Figure 2.

[0066] The mast assembly 12 includes a biasing means 16 arranged so as to bias the mast 14 toward the raised condition. In this example, the biasing means 16 is provided in the form of a counter weight 18. The counter weight 18 includes an aperture 32 into which the mast 14 is received. A tether (not shown) may be attached to a top 100 of the mast to lower or pull the mast 14 to the lowered condition.

[0067] The mast assembly 12 includes a base 22 adapted to support the counter weight 18 and mast 14, and a lighting head 20 supported by the mast 14. The body 11 is provided in the form of a chassis 26. A lower portion 24 of the base 22 is adapted to fit with the chassis 26 of the mobile lighting plant 10, and an upper portion 28 of the base 22 is adapted to support a pivot support shaft 30 so as to facilitate pivotal movement of the counter weight 18 and the mast 14 between the raised and lowered conditions. The mast assembly 12 includes one or more damping or isolator assemblies 101 located between chassis 26 and the mast head 14, for example being located between the base 22 and the chassis 26 and/or between the mast 14 and the counter weight 18, that are arranged to damp vibration or other movement between the chassis 26 and the light head 20. The damping or isolator assemblies 101 are further detailed below.

[0068] The chassis 26 includes spaced apart skids 42 which extend along an underside of opposing sides 44 of the chassis 26 and a tubular nudge bar 46 which substantially skirts the chassis 26. The chassis 26 supports a work platform and a series of power supply and control components such as a control box 50, a generator 52 and a fuel tank 57. In this example, the base 22 includes compartments 47 in which batteries 54 are stored. The location of the batteries 54 within the base 22 assist to maintain an even and centralised weight distribution of lighting plant 10.The control box 50, the generator 52 and batteries 54 forming a power supply system 56 for supplying electrical power to the light panels 40. The lighting plant 10 including the chassis 26 and mast assembly 12 are substantially formed of welded steel components.

[0069] The base 22, and the counter weight 18, is centrally located on the chassis 26 so as to assist to maintain an even and balanced weight distribution. This allows the chassis 26 to be more easily moved on the spaced apart skids 42 by a machine such as bulldozer pushing on the tubular nudge bar 46. The generator 52 and fuel tank 57 are also located at opposing ends of the chassis 26 to assist with even weight distribution along the skids 42.

[0070] A related example of the mobile lighting plant 10 having a slightly different geometry is shown in Figure 3 and 4. This example is in essence the same as that shown in Figures 1 and 2, although a slightly different geometry has been employed and the batteries 54 may be supported by a battery support bench 55 which is in turn fitted over a fuel tank 57 for the generator 52. The lighting platform 10 may also include removable safety rails 59.

[0071] Referring additionally to Figure 5, the base 22 includes two spaced apart supports 34 which are arranged so as to allow the passage of the counter weight 18 between the spaced apart supports 34. The supports 34 including spaced apart bearing housings 36 between which the pivot shaft 30 passes. The pivot shaft 30 (shown best in Figure 6) is coupled to and passes through the counter weight 18. The spaced apart supports 34 and the counterweight 18 include spaced corresponding locking apertures 60 through which a locking pin 58 is able to be passed so as to secure the counter weight 18, and the mast 14, in at least one of the raised and lowered conditions.

[0072] Referring now to Figures 6 and 7, the mast assembly 12 includes a rotatable lighting head 20 supported by the mast 14. The lighting head 20 includes a supporting beam 38 which supports eight spaced apart light panels 40. Each of the light panels 40 includes a series of light emitters 71 which may be provided in the form of a LED (Light Emitting Diode) array. The rotatable lighting head 20 is coupled to a first actuation mechanism 70 (shown best in Figure 7) adapted to rotate the lighting head 20 about the axis of the mast 14. In this example, the mast 14 is hollow and the first actuation mechanism 70 extends between an actuator 72 accessible from a lower section 74 of the mast 14 and an elongate coupling shaft 76 (shown in Figure 7) which extends lengthwise internally of the mast 14 between the actuator 72 and the light head 20.

[0073] The light head 20 is supported by a rotatable bearing arrangement 78 such that the first actuation mechanism 70 is able to rotate the light head 20 about and relative to the mast 14. The rotatable arrangement 78 includes a bearing 118, a split bearing 120 and split keep the plate 122 which are arranged so as to allow the elongate coupling 76 and a coupled hub 124 to rotate relative to the mast 14. The elongate coupling shaft 76 includes a gear 126 arranged to be driven by the actuator 72. The elongate coupling 76 is provided in the form of a hollow tube 131 so as to allow the passage of electrical cables 132 through the elongate coupling 76 to the lighting head 20.

[0074] The actuator 72 may be provided in the form of a hand driven worm drive gear box 73 fitted in use to the side of the mast immediately adjacent to the gear 126. The worm drive may be a 30:1 gear box to which a handle (not shown) is attached to drive the gear box 73. A horizontal shaft 77 supporting a corresponding bevel gear 79 may extend between and couple the worm drive gear box 73 and the gear 126 to allow the rotational driving of the hollow elongate coupling shaft 76.

[0075] The mast assembly 12 further includes a second actuation mechanism 80 configured to angle or pitch the light head 20 in a vertical direction. The second actuation mechanism 80 includes a push rod 82 which extends between a second actuator 84 located toward a lower section of the mast 14 and the lighting support beam 38. The mast 14 includes supporting guides 86 which are spaced along the outer surface of the mast 14 to guide the push rod 82 between the second actuator 84 and the lighting support beam 38. The guides 86 are arranged to allow sliding movement of the push rod 82 relative to the mast 14.

[0076] The push rod 82 includes at least one universal joint 128 located toward the coupling between the push rod 82 and the lighting support beam 38. The universal joint 128 allowing the push rod 82 or a section of the push rod 82 to become angled when the lighting head 20 is rotated by the first actuation mechanism 70. This enables rotation of the lighting head 20 whilst the second actuation mechanism 80 maintains a coupling between the push rod 82 and the lighting support beam 38 to angle or pitch the light head 20. The second actuator 84 may be provided in the form of a hand operable jack 130 (shown best in Figure 8). The jack 130 includes a handle 132 coupled to a threaded section 134 of the push rod 82. The handle 132 is arranged to be actuated to rotate the threaded section 134 of the push rod 82 to extend and retract the lighting head 20 so as to change the angle or pitch of the light panel 40 coupled to the lighting head 20 as is further described bellow with reference to Figures 11 and 12.

[0077] Referring now to Figures 8, 9 and 10 there is shown detailed views of the coupling between the base 22, the counter weight 18 and the mast 14. The counter weight aperture 32 is provided in the form of a sleeve 90 (best shown in Figure 10) into which an end 92 of the mast 14 is received. The entry to the sleeve 90 includes a seating flange 96 to which a seated flange 94 of the mast 14 is coupled. The seated flange 94 of the mast 14 is located spaced apart from the end 92 of the mast 14 and includes a reinforced sleave 98 (best shown in Figure 8) which extends upwardly toward a top end 100 of the mast 14 (best shown in Figure 1). The isolator or vibration damping assembly 101 includes a mast isolator or vibration damping assembly 102. The mast isolator or vibration damping assembly 102 is fitted between or includes components fitted between the seating flange 96 and the seated flange 94 so as to form a flange coupling arrangement 93 so as to allow damped movement of the mast 14 relative to the counter weight 18 is further described below.

[0078] The end 92 of the mast 14 includes a cutout or keyway 116 to locate and support the mast 14 on the pivot support shaft 30. The key way 116 and pivot support shaft 30 are not rigidly connected to one another so as to allow the mast 14 to float in the sleeve 90 and allow play or movement between the mast 14 and the counter weight 18 which may then be used to damp or isolate the mast 14 from vibration generated by the chassis 26 of the lighting plant 10 using the isolator or vibration damping assembly 102.

[0079] The mast isolator or vibration damping assembly 102 is fitted between the seating flange 96 and the seated flange 94 so as to damp or isolate the movement of the mast 14 from the counter weight and the chassis 26 of the lighting plant. More specifically, the mast isolator assembly 102 includes a rubber gasket 104 fitted between the seating flange 96 and the seated flange 94. In this example, the gasket 104 may be a 2 mm rubber gasket. The mast isolator assembly 102 further includes a fastener damper 106 which is fitted to an internal surface of apertures 108 through which fasteners 110 are passed to secure the seating flange 96 to the seated flange 94 and hence secure the counter weight 18 to the mast 14. The fastener 110 may be a shoulder bolt seated on a washer 111 located between the apertures 108 and an underside of the shoulder bolt.

[0080] The mast isolator assembly 102 further includes a further isolator or damper 103 in the form of a mast damping sleave 112 which is fitted in a gap 114 between the external surface of the mast 14 and the internal surface of the sleave 90 of the counter weight 18 into which the mast 14 is received. As may be appreciated from the above, the floating of the mast 14 on the pivot shaft 30, the gap 114 and the isolator arrangement 102 allows damped play or damped movement between the mast 14 and the counter weight 18. This is particularly advantageous to assist to reduce the transmission of vibration or movement to the lighting head 20. More specifically, the secure the coupling between the chassis 26 and the mast 14, the counter weight arrangement to maintain the mast in the normally raised position and the isolator arrangement 102, which minimises or reduced the transmission of vibration, allows the mast 14 to be transported in the normally raised position.

[0081] In some examples, a base or chassis isolator 121 (as shown on Figure 1) may be fitted to an underside of the base 22 between the chassis 26 and the base 22. The chassis isolator 121 may be provided in the form of a rubber pad or similar resilient material on which the base 22 is seated. The chassis isolator 121 provides an additional means to damp the vibration between the chassis 26 of the plant 10 and the lighting head 20.

[0082] The counter weight 18 includes a housing 136 into which ballast, such as concrete, may be received and a drain conduit 135 extending between a bottom of the mast receiving sleave 90 and a normally lower face of the counter weight 18. The side of the mast 14 also includes an aperture 137 arranged to allow the electrical cables to pass from the hollow elongate coupling 76 of the first actuation mechanism to one or more components of the power supply system 56.

[0083] Referring now to Figures 11 and 12, the lighting head 20 is shown in further detail. The support beam 38 is pivotally coupled to a support plate 138 which is in turn coupled via fasteners 140 to the coupling hub 124 which is in turn rotatably coupled to the mast 14, as shown in Figure 7. The support plate 138 includes a pivot support 142 which received a pin 144 to pivotally couple the support beam 38 to the support plate 138 and the mast 14. The support beam 38 includes pitch control bracket 146 which extends outwardly from the support beam 38 so as to provide a level arm against which the pull rod 82 may act to pitch the light support beam 38, and the attached light panel 40, about the pin 144.

[0084] Accordingly, the lighting head 20 may be rotated about axis of the mast 14 by the first actuation mechanism 70 and may also be pitched in a direction perpendicular to the axis of the mast 14 by the second actuation mechanism 80. Each of the first and second actuation mechanism having respective actuators 72, 84 which are located toward to lower section 74 of the mast 14 so as to be accessible by a user standing on the platform 48 of the chassis 26.

[0085] Referring to Figure 13, there is provided a schematic of the power supply system 56. The power supply system 56 includes a controller 50 electrically connected between the light panels 40, the batteries 54 and the generator 52. The controller 50 may include programmable logic controller having a processor and memory and a user interface to input commands to the programmable logic controller. The generator 52 may be a diesel generator and the batteries 54 may include a series or bank of batteries. The power supply system 56 is a 24 Volt system and the light panels 40 include 24 Volt LED lights.

[0086] In this example, the controller 50 is configured to cycle the generator 52 so as charge the batteries 54 when voltage thereof falls below a pre-determined lower voltage level or charge. Accordingly, the power supply system 56 may further include a power or voltage sensor configured to monitor the charge of the batteries and provide feedback to the controller 50. The batteries 54 then maintain a per-determined power level to the light panels 40 to keep the lights illuminated. If the voltage of the batteries 54 drops below the per-determined lower voltage or charge, the controller 50 starts the generator 52 to charge the batteries 54 to a pre-determined high charge level. Once the pre-determined high charge level is reached, the controller 50 then stops the generator 52 and continues to monitor the charge of the batteries 54.

[0087] Referring now to Figures 14 to 25, there is shown a further example of the lighting plant 210 in which like numerals are used to denote like parts. In this example, the overall functionality of the lighting plant 210 is similar to that described above. However, in this example there are modifications to the mast assembly 212 and, in particular, the coupling and vibration isolation or damping between the mast assembly 212 and the chassis 226.

[0088] Referring firstly to Figures 14 to 17, in this example, the mast assembly 212 further includes an external support arrangement 301 including wires 303 extending from the counter weight 218 to the light head 220. The external support arrangement 301 includes a spacer 305 provided in the form of a hoop frame 306 located intermediate the mast 214. The wires 303 are coupled at opposing ends therefor to tensioning lugs 307, 309 provided on the counter weight 218 and light head respectively 220. In this example, four wires 303 are provided that are tensioned and pass over the hoop spacer 305 so as to be 90 degrees apart from one another. The external support arrangement 301 thereby functions to stiffen the mast 114.

[0089] The hoop frame 306 includes round bar 315 connected with sleave nuts 311 and wire guides 313 through which the wires 303 pass. Spreader bars 315a are arranged to space the outer hoop frame 306 from an inner hoop frame 317 that extends directly around the circumference of the mast 214.

[0090] Referring now to Figures 18 to 21, in this example, the sleave 290 extends to a base plate 341 located at or toward the bottom of the counter weight 218. Accordingly, the mast 114 extends substantially through the counter weight 218. Similarly, to the first example above, the housing 336 of the counter weight 218 is filled with ballast such as concrete that encases the sleave 290. The sleave 290 being preferably provided in the form of a metal tube or the like.

[0091] As is best shown in Figure 18, in this example the mast damping arrangement 302 includes damping elements 315 provided in the form of damping strips 343 extending lengthwise between the sleave 290 and a received section 345 of the mast 214. The fit between the sleave 290 and the mast 214, further described below with reference to Figures 20 and 21, is arranged such that there is some play between the sleave 290 and the mast 214 that is damped by the damping strips 343. Preferably, there is no hard connection between the sleave 290 and the mast 214, and the coupling may include a flexible flange coupling arrangement 293 similar to that shown in Figure 10 in relation to the first example.

[0092] In the example shown in Figure 20, the base plate 341 includes a locator 319 that is fittingly received by the mast 214 and the sleave 290 is a straight sided or non-tapered tube dimensioned to receive the mast 214. However, in the example shown in Figure 21, the sleave 290 tapers inwardly, so as to narrow slightly in diameter, toward the base plate 341 so as to from a friction fit, preferably a light friction fit with the base of the mast 214 thereby lightly coupling the mast 214 and the counter weight 218.

[0093] In this example, the pivot support shaft 230 (shown best in Figure 19) is provided in the form of stub-shafts 321 extending from opposing sides of the counter weight 218. The stub-shafts 321 do not extend through or support the mast 214. Rather, the stub-shafts 321 are bolted onto the opposing sides of the housing 336. As is best shown in Figures 22 and 23, the spaced apart supports 234 include bearing housings 236 which each rotatably support a respective one of the stub-shafts 321.

[0094] Opposing inner faces 323 of the supports 234 are fitted with friction reducing parts 325 in the form of Teflon™ pads 327. The pads 327 are arranged to fit between the inner faces 323 and the outer faces of the counter weight 218 to inhibit lateral movement of, and locate, the counter weight 218. The Teflon™ pads 327 providing a bearing surface across which the counter weight 218 may slide or pass during movement of the mast 214 between the lowered and raised conditions.

[0095] Referring now more specifically to Figures 22 to 26, in this example a more sophisticated isolation or vibration damping arrangement 331 is provided between the base 222 of the mast assembly 212 and the chassis 226 is described in more detail. The vibration damping arrangement 331 includes compression damping assemblies 333 and damping bolt assemblies 335 arranged between the base 222 and the chassis 226.

[0096] The compression damping assemblies 333 preferably include shear compression mounts 347 that are respectively mounted to the underside 337 of the base 222 and the topside 339 of the chassis 226. The compression mounts 335 include a rubber or similar materials 349 sandwiched between metal pads or plates 341. The compression mounts 335 generally support the weight of the mast assembly 212 and allow relative damped movement between the chassis 226 and the mast assembly 212.

[0097] The damping bolt assemblies 335 include a bolt 363 having a head 365, washer 367, a threaded shank 369 and a damping part 361 provided in the form of a urethane cone ring 373. The urethane ring 373 is located on a topside 355 of the base plate 357 and is captured between the head 365 and washer 367 of the bot 363 and the topside 355 of the base plate 357. The bolt 363 then passes through a gap 359 between the base 222 and the chassis 226, as defined by the shear compression mounts 347, and is threadedly coupled to the chassis 226.

[0098] In use, the damping bolt assemblies 335 are arranged to provide vibration damping in a vertical or tension direction which opposes that of the shear compression mounts 347 which function under compression and shear. The damping bolt assemblies 335 functions in conjunction with the shear compression mounts 335 to assist to reduce and control vibration between the chassis 226 and the mast assembly 212 and ultimately the light head 220.

[0099] The underside 337 of the base 222 and the topside 339 of the chassis 226 are also fitted with likewise friction or sliding parts 381 provided in the form of Teflon pads 383. The Teflon pads 383 are arranged centrally of the respective base 222 and chassis 226 so as to be located proximate to one other and to provide a near friction free interface between the mast assembly 212 and the chassis 226. This arrangement allows movement, which is damped by the vibration damping arrangement 331, between the chassis 226 and the mast assembly 212, and ultimately the light head 220. Accordingly, movement of the chassis 226 is at least partially isolated from of the mast assembly 212 thereby assisting to protect the light head 220.

[00100] Advantageously, there has been described a mobile lighting plant or skid having a mast assembly including at least one isolator or damping element to damp or reduce the transmission of vibration between the mobile lighting platform and the mast which carries vibration sensitive components, in particular, lighting panel supported by the lighting head. The mast assembly is adapted to be in a normally elevated condition and is configured to advantageously allow the mobile lighting plant to be moved whilst the mast is in the elevated condition. The mast may be moved to a lowered condition by, for example, attaching a tether such as a rope to the top of the mast and pulling the mast down to lie adjacent to the platform. The mast assembly may then be secured in the lowered condition with a securing pin.

[00101] The mobile lighting plant is mounted on a skid having a nudge bar extending around the skid so as to allow the mobile lighting plant to be moved by a bulldozer or similar equipment. Advantageously, the mast assembly, in particular the counter weight, is located centrally of the chassis of the lighting plant which assists with balancing the mobile lighting plant so as to have an even weight distribution. The placement of the batteries, diesel tank and diesel generator toward either end of the lighting plant also assists to maintain this even weight distribution to assist with the skid moving of the lighting plant. It is also noted that the mast being able to be transported in the elevated condition allows for the sensitive components, in particular the lighting head and associated light panels, to be located well away from the machinery such as the bulldozer which may be used to move the skid.

[00102] Further advantageously, the mast assembly includes two separate hand operable actuation mechanisms to control both the rotation of the lighting head and also the pitch of the lighting head. This allows for an operator located on the platform of the lighting plant to be able to direct the beam of the lights to a desired location. The power system of the lighting plant which powers the lights also includes advantageous aspects combining a diesel generator with chargeable batteries. This allows, for example, the diesel generator to be run for short intervals to power the batteries that, in turn, power the lights. Accordingly, as the diesel generated does not need to be continually run, the noise on site will be reduced as well as associated fuel savings and reduce wear on the diesel motor.

[00103] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps [00104] The reference in this specification to any known matter or any prior publication is not, and should not be taken to be, an acknowledgment or admission or suggestion that the known matter or prior art publication forms part of the common general knowledge in the field to which this specification relates.

[00105] While specific examples of the invention have been described, it will be understood that the invention extends to alternative combinations of the features disclosed or evident from the disclosure provided herein.

[00106] Many and various modifications will be apparent to those skilled in the art without departing from the scope of the invention disclosed or evident from the disclosure provided herein.

Claims

The claims defining the Invention are as follows:

1. A mast assembly for a mobile lighting plant, the mast assembly including: a mast pivotally coupled to a chassis of the mobile lighting plant so as to be moveable between a raised condition and a lowered condition; and a biasing means configured to bias the mast toward the raised condition.
2. The mast assembly according to claim 1, wherein the mast assembly includes an isolator assembly configured to inhibit the transmission of vibration between the chassis and a light head carried by the mast.
3. The mast assembly according to claim 2, wherein the biasing means is provided in the form of a counter weight adapted to support the mast.
4. The mast assembly according to claim 2, wherein the isolator assembly incudes a mast isolator configured to provide damping between the counter weight and the mast.
5. The mast assembly according to claim 4, wherein the counter weight includes an aperture into which the mast is received, and wherein the mast isolator is at least partially fitted between the aperture and the mast.
6. The mast assembly according to claim 5, wherein the mast isolator is provided in the form of a resilient material and wherein the aperture is provided in the form a sleave dimensioned so as to allow the fitting of the resilient material between the mast and the sleave thereby allowing relative damped movement between the sleave and the mast.
7. The mast assembly according to any one of claims 3 to 6, wherein the mast assembly includes a base adapted to support the mast, a lower portion of the base being supported by the chassis, and an upper portion of the base being adapted to pivotally support the counter weight so as to allow movement of the mast between the raised and lowered conditions.
8. The mast assembly according to claim 7, wherein the base includes spaced apart supports arranged to allow passage of the counter weight therebetween.
9. The mast assembly according to claim 8, wherein each of the spaced apart supports includes a bearing support arranged to pivotally couple with a shaft carried by the counter weight.
10. The mast assembly according to any one of claims 7 to 9, wherein the isolator assembly includes at least one base isolator located between the base and the chassis of the mobile lighting plant.
11. The mast assembly according to claim 10, wherein the at least one base isolator is provided in the form of a plurality of base isolators adapted to provide damping in response to relative movement between the chassis and base in at least two directions including in the vertical and lateral directions.
12. The mast assembly according to claim 10, wherein the at least one base isolator is provided in the form of a plurality of base isolators including at least one vertical damper arranged to damp relative movement between the base and chassis in a vertical direction and at least one shear damper arranged to damp relative movement between the base and chassis in a lateral direction.
13. The mast assembly according to any one of claims 7 to 12, wherein at least one friction reducing part is located between the base and the chassis. 14 The mast assembly according to claim 13, wherein the at least one friction reducing part is provided in the form of corresponding friction reducing bearing pads carried respectively by the base and the chassis.
15. The mast assembly according to any one of claims 2 to 14, wherein the chassis is arranged to be movable in at least one of a forward and reverse direction, and wherein the mast assembly is adapted to allow the mast to move in a plane aligned with at least one of the forward and reverse directions.
16. The mast assembly according to any one of claims 3 to 14, wherein the chassis is arranged to be movable in at least one of a forward and reverse direction, and wherein the counter weight of the mast assembly is adapted to allow limited relative movement of the mast in a plane aligned with the forward and reverse direction.
17. The mast assembly according to any one of the previous claims, the mast assembly including an actuation mechanism adapted to rotate the light head supported by the mast.
18. The mast assembly according to claim 17, wherein the mast assembly includes an actuator accessible from a lower section of the mast and a coupling which extends internally of the mast between the actuator and the light head.
19. The mast assembly according to claim 18, wherein the coupling includes a conduit arranged to allow for passage of an electrical connection between the light head and a power supply located externally of the mast assembly.
20. The mast assembly according to any one of claims 15 to 19, the mast assembly further includes a second actuation mechanism adapted to adjust pitch a light of the light head.
21. The mast assembly according to claim 20, wherein the second actuation mechanism includes a second actuator accessible from the platform and a second coupling which extends externally of the mast between the second actuator and the light head.
22. The mast assembly according to claim 21, wherein the second coupling is a rod including a least two articulated sections which are moveable so as to allow rotation of the light head whilst the rod is coupled between the light head and the second actuator.
23. A lighting plant including a mast assembly as defined in any one of the previous claims.
24. The lighting plant according to claim 23, wherein the plant includes a chassis supported by skids, and wherein the mast assembly is substantially centrally located on the chassis so as to provide a substantially even weight distribution.
25. The lighting plant according to claim 23 or 24, wherein the lighting plant further includes a power system including a controller, a generator and at least one battery, wherein the controller is configured to selectively operate the generator to charge the at least one battery so as to maintain power to a light of the light head.
26. The lighting plant according to claim 23 or 24, wherein the lighting plant includes at least one of a generator, an associated generator fuel tank and at least one battery are located toward opposing ends of the chassis relative to one another so as to provide a substantially even weight distribution.
27. The lighting plant according to any one of claims 22 to 26, wherein a base of the mast assembly includes a compartment in which at least one battery is located.
28. A method of operating a mast assembly for a mobile lighting plant, the method including the steps of: actuating a mast of the mast assembly to pivotally move the mast from a raised to a lowered condition in which a light head carried by the mast is accessible; and releasing the mast such that a biasing means of the mast assembly returns the mast to an ordinarily raised condition.
29. A method of moving a lighting plant having a mast assembly including a pivotally moveable mast biased toward an ordinarily raised condition, the method including the steps of: bearing a vehicle on at least one of a forward and rear end of a chassis of the lighting plant so as to move the lighting plant in at least one of forward and rear direction, the mast being in the ordinarily raised condition with at least one isolator of the mast assembly operating so as to inhibit the transfer of vibration between the chassis and a mast head carried by the mast.