CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Not applicable.

FIELD

[0002] Embodiments of the present disclosure relate generally to lighting arrangements for mobile machines and to mobile machines having such lighting arrangements.

BACKGROUND

[0003] Mobile machines often have lights fitted, sometimes referred to as working lights, which illuminate part of the mobile machine and/or the part of the environment surrounding the mobile machine. Improving illumination is beneficial in enabling a mobile machine to be used when the natural light may not be sufficient, thus enabling the mobile machine to be used for longer. Furthermore, mobile machines increasingly have automated systems which require the use of cameras whose effectiveness requires adequate lighting. There is then a continuing need to improve illumination by adding additional light units to a mobile machine and/or by increasing the power of the light units used. However, this can lead to problems in packaging of the light units on the mobile machine and in ensuring adequate cooling for the light units.

[0004] Reference to "mobile machines" herein should be understood as including a broad range of, usually self-propelled, mobile machines and plant, including mobile machines used in agriculture, such as combine harvesters, bailers and the like, as well as mobile machines used in the construction industry, such as excavators, bulldozers, front loaders, backhoes, and the like. The term "mobile machine" should also be understood as encompassing vehicles and especially vehicles which can be used off-road, including in particular agricultural vehicles such as tractors and the like, and those used in the construction industry, such as dump trucks, diggers and the like. BRIEF SUMMARY

[0005] In an aspect of the invention there is provided a lighting arrangement for a mobile machine comprising at least one light unit located in a housing which defines an aperture, the light unit having a front end through which light is emitted from the unit in use, a rear end opposite the front end, and a side region extending between the front and rear ends, the front end projecting out of, or aligned with, the aperture, a first set of cooling fins on the side region of the light unit which are aligned generally in a front to rear orientation of the light unit and a second set of cooling fins on the rear end aligned generally in a top to bottom orientation of the light unit, the housing further defining at least one air vent spaced from the aperture though which air can pass between an interior and exterior of the housing, wherein an air flow path is defined between the aperture and the at least one air vent passing through the first and second sets of cooling fins.

[0006] Advantageously, the air flow path defined by the light unit and the housing enables a flow of cooling air to be set up which passes through both sets of cooling fins to help cool the light unit in use. Reference to air flowing "through" a set of cooling fins should be understood as including a flow of air between and over the cooling fins in any given set such that in use heat is transferred from the cooling fins to the air.

[0007] The at least one air vent may connect the interior of the housing with the ambient environment exterior to the mobile machine.

[0008] The first and second sets of cooling fins may be interconnected so that the cooling fins extend continuously from set into the other. Looked at another way, the first and second sets of cooling fins may be considered first and second portions of a single set of cooling fins.

[0009] The aperture may be at least partially aligned with a direction of movement of the mobile machine. The arrangement may be such that at least under certain circumstances when the mobile machine moves in that direction of movement, air is caused to flow through the aperture, through the first and second sets of cooling fins, and to exit the housing through the at least one air vent by a ram air type effect. The aperture may be at least partially aligned in a forward direction of movement of the working machine such that when the mobile machine moves in a forward direction, air is forced in a ram air effect in through the aperture over the first and second sets of cooling fins and exits the housing through the at least one air vent.

[0010] The arrangement may be configured such that in use where there is no ram air effect present, e.g. where the aperture is not at least partially aligned with a direction of movement of the mobile machine and/or when the mobile machine is stationary, air flow along the air flow path arises due to convection in use. A convective air flow may be in either direction along the flow path depending on whether the at least one air vent is located above or below the light unit. In an embodiment, the first set of cooling fins are located on an upper part of the side region and the least one air vent is located below the light unit. In this embodiment, air heated by the light unit will tend to rise toward and out of the aperture setting up a convective air flow in which fresh air is drawn in through the at least one air vent and passes over the second set of cooling fins and the first set of cooling fins before exiting through the aperture. In an alternative embodiment, the first set of cooling fins are located on a lower part of the side region and the least one air vent is located above the light unit. In this embodiment, air heated by the light unit will tend to rise toward and out of the at least one air vent setting up a convective air flow in which fresh air is drawn in through the aperture and passes over the first set of cooling fins and the second set of cooling fins before exiting through the at least one aperture.

[0011] The side region of the light unit may have an indented portion with un-indented portions either side (when considered in a lateral direction of the light unit) of the indented portion, the first set of cooling fins being located in the indented portion. The arrangement may be configured such that the distal outer ends of the fins in the first set of cooling fins do not project above the outer surfaces of the un-indented portions. The arrangement may be configured such that the distal outer ends of the fins in the first set of cooling fins are aligned with outer surfaces of the un-indented portions. The side region of the light unit may have an upper wall, a lower wall, and opposed lateral walls which interconnect the upper and lower walls. The indented portion may be defined centrally within one of the upper and lower walls. Portions of said one ofthe upper and lowerwalls either side of the indented portion beingthe un-indented portions. [0012] The housing may have walls which are proximal to the outer surfaces of unindented portions of the wall or walls defining the side region, the indented portion defining a port through which air can flow into or out of the housing.

[0013] The housing may be configured to constrain air to flow along the flow path through the first and second sets of cooling fins. The housing may include a rear wall extending proximal to distal end regions of the cooling fins in the second set of cooling fins and a side wall (e.g. an upper wall or a lower wall) extending proximal distal end regions of the cooling fins in the first set of cooling fins. The at least one air vent may comprise one or more apertures in a wall of the housing, which may be lower wall or an upper wall. The at least one air vent may comprise a gap between walls of the housing or it may be that the housing does not fully encapsulate the light unit allowing air to pass into or out of the second set of cooling fins. The housing may not have a lower wall, for example.

[0014] The cooling fins in the first set may extend from a forward edge of the side region rearward towards the rear end.

[0015] The housing may define more than one aperture and there may be a respective light unit associated with each aperture. In this case, the at least one air vent may be operatively associated with two or more of the light units.

[0016] There may be a plurality of air vents.

[0017] The light unit may be a working light.

[0018] The housing may be defined by part of the bodywork of the mobile machine.

[0019] In accordance with another aspect of the disclosure, there is provided a mobile machine having a lighting arrangement according to the previous aspect of the disclosure defined above.

[0020] The housing may be defined by part of the bodywork of the mobile machine.

[0021] The mobile machine may have an operator cab having at least one peripheral cab wall and a roof section mounted to the upper end of the at least one peripheral cab wall, wherein the housing is defined at least partly by or within a part of the roof section. The housing may be defined at least partly by or within a peripheral edge region (eaves) of the roof section which extends outwardly beyond the at least one peripheral cab wall. The at least one air vent may be located in a lower wall of the peripheral edge region of the roof section below the light unit and which overhangs said at least one peripheral cab wall. In this embodiment, the first set of cooling fins may be provided on an upper portion of the side edge region of the light unit. The peripheral edge region of the roof section may define a plurality of apertures with a respective light unit associated with each aperture. The peripheral edge region may define an internal cavity in which rear end regions of the light units are located, the internal cavity being closed at a lower end by the lower wall in which the at least one air vent is defined. There may be a plurality of air vents defined in the lower wall. The at least one peripheral wall of the cab may include a front wall, a rear wall, and a pair of opposed side walls. The aperture may be provided in a forward facing part of the peripheral edge region of the cab roof structure.

[0022] Rather than being defined in a peripheral edge portion of a roof section of the cab, the housing may be defined in an alternative part of the body work of the mobile machine. In one embodiment, the housing is defined by part of the bodywork forming part of an engine compartment of the mobile machine. In this location the lighting arrangement may be connected to an engine cooling system arranged inside of the engine compartment. The indented portion of the light unit may be used as an air inlet for the engine cooling system by pulling air into the engine cooling system in an active or semi active manner, for example by a blower of the engine cooling system.

[0023] The lighting arrangement may be configured such that the first set of fins are provided on a lower portion of the side edge region of the light unit, the at least one air vent being provided in a wall of the bodywork above the light unit.

[0024] The mobile machine may be an agricultural tractor.

[0025] Within the scope of this application it should be understood that the various aspects, embodiments, examples and alternatives set out herein, and individual features thereof may be taken independently or in any possible and compatible combination. Where features are described with reference to a single aspect or embodiment, it should be understood that such features are applicable to all aspects and embodiments unless otherwise stated or where such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] One or more embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0027] FIG. 1 is a side view of a tractor incorporating a lighting arrangement according to an aspect of the disclosure;

[0028] FIG. 2 is a perspective view from the front and to one side of an embodiment of light unit forming part of a lighting arrangement according to an aspect of the disclosure;

[0029] FIG. 3 is a perspective view from the rear and to one side of the light unit of FIG. 2;

[0030] FIG. 4 is a view from the front of the light unit of FIGS. 2 and 3 mounted in a housing to form a lighting arrangement according to an aspect of the disclosure, in which the housing is illustrated schematically;

[0031] FIG. 5 is a view from one side of the light unit and housing of FIG. 4, the housing illustrated schematically in cross section;

[0032] FIG. 6 is a perspective view from the front and to one side of the light unit and housing of FIGS. 4 and 5, illustrating a flow of cooling air created by a ram air effect when a mobile machine to which the light unit is mounted moves in a direction with which the light unit is aligned, parts of the housing being illustrated schematically;

[0033] FIG. 7 is a perspective view from the rear and to one side of the light unit and housing of FIGS. 4 and 5, illustrating a convective flow of cooling air, parts of the housing being illustrated schematically;

[0034] FIG. 8 is a perspective view of part of a roof section of a tractor cab incorporating an embodiment of a lighting arrangement in accordance with an aspect of the disclosure; and

[0035] FIG. 9 is view of part of the roof section of FIG. 8 showing a peripheral edge region of the roof section including the lighting arrangement in cross section. DETAILED DESCRIPTION

[0036] Embodiments of a lighting arrangement for a mobile machine in accordance with an aspect of the disclosure will now be described with reference to the accompanying drawings. The embodiments described are adapted for use in a tractor but lighting arrangements in accordance with the disclosure can be adapted for use with other types of mobile machine including, without limitation, any suitable mobile machine used in agriculture or construction and vehicles adapted for off-road use.

[0037] With reference to FIG. 1, a tractor 10 has front wheels 12 on a front axle, rear wheels 14 on a rear axle and a frame 16 supported on the front and rear axles. Mounted on the frame 16 and/or on the rear axle is an operator cab 18. The cab 18 includes a front wall 20 and a rear wall 22 interconnected by a pair of opposed side walls 24 (only one of which is visible). The cab 18 is enclosed at the top by a roof section 26. The cab 20 defines an interior space 27 for an operator of the tractor and houses various controls. In front of the cab 18 is an engine compartment 28 housing an IC engine or other prime mover, such as an electric motor or a hybrid power unit or a combination of any of these.

[0038] A lighting arrangement 30 is incorporated into a peripheral edge region 32 of the roof section which extends beyond (overhangs) the front wall 20 of the cab. The lighting arrangement 30 includes at least one light 34 unit mounted in a housing 36 which may be defined within and/or by the peripheral edge region 32 of the roof section 26.

[0039] An embodiment of a light unit 34 suitable for use in the lighting arrangement is illustrated in more detail in FIGS. 2 and 3. The light unit 34 has a front end 38, a rear end 40, and a side region 42 extending between the front and rear ends 38, 40. The light unit 34 includes a casing 44 which has a rear end face 45 and one or more peripheral walls which define the side region 42 and which together with the rear end face 45 define an interior volume in which a light source is located. The light source may be any suitable light source such as, without limitation, one or more LED bulbs, for example. The casing 44 is closed at the front end 38 of the light unit by a transparent or translucent cover 46 through which light emitted by the light source passes. The cover 46 may be in the form of a lens which focusses or otherwise directs the light emitted by the light source. Details of the functional components (e.g., interior components and connectors) of the light unit will not be described further as these are not relevant to the present disclosure but will typically include electronic circuitry required to connect the light source to an electrical system of the tractor 10 and may include one or more reflectors for directing light emitted by the light source out through the front cover 46.

[0040] On the exterior of the light unit 34 are a first set of cooling fins 50 and a second set of cooling fins 52. The cooling fins 50 of the first set are located on the exterior of the side region 42 of the casing 44 and are aligned in a front to rear direction of the light unit. In the present embodiment, the light unit 34 is generally rectangular in lateral cross section so that the side region 42 includes an upper wall 54, a lower wall 56, and a pair of opposed lateral walls 58, 60 which extend between the upper and lower walls. The upper wall 54 has a laterally central indented portion 62 with un-indented portions 64 either side. The outer surface of the indented portion 62 is offset inwardly relative to the outer surfaces of the un-indented portions 64. The first set of cooling fins 50 are located on the indented portion 62, with distal outer end surfaces 50a of the cooling fins 50 being aligned with, or slightly below, the outer surfaces of the un- indented portions 64. The cooling fins 50 in the first set extend from proximal the front end 38 of the light unit rearward towards the rear end wall 45. In the present embodiment, the cooling fins 50 of the first set are tapered, reducing in height at their rear ends prior to reaching the rear end wall 45 of the casing 44. However, in alternative embodiments the cooling fins in the first set could extend to the rear wall. The cooling fins 50 in the first set are aligned generally parallel to one another with gaps between them so that air is able to flow across the top of the light unit 34 through the first set of cooling fins. It will be appreciated that the fins in the first set 50 need not be aligned parallel to one another provided they enable air to flow in a direction from the front to the rear of the light unit or form the rear to the front. Reference to air flowing "through" the first set of cooling fins should be understood as including air flowing between and/or over the cooling fins in the first set of cooling fins such that heat can be transferred from the fins to the air.

[0041] The fins 52 of the second set project rearward from the rear end wall 45 and are aligned in a direction from top to bottom of the light unit 34. The fins 52 in the second set are distributed across the rear face 45 and are aligned generally parallel to one another so that air is able to flow through the second set of cooling fins in a direction from top to bottom of the light unit 34 or from the bottom to the top. It will be appreciated that the fins 52 in the second set need not be aligned parallel to one another provided they enable air to flow in a direction from top to bottom of the light unit. Reference to air flowing "through" the second set of cooling fins should be understood as including air flowing between and/or over the cooling fins in the second set of cooling fins such that heat can be transferred from the fins to the air.

[0042] The cooling fins 50, 52 may be formed integrally with the casing 44 which can be made from any suitable material, including metallic materials. The casing 44 can be made by any suitable process and could be a cast or moulded component, for example.

[0043] In an embodiment where the cooling fins 50 of the first set extend to the rear wall, the fins 50, 52 of the first and second sets could be connected. In this context, reference to first and second sets of fins 50, 52 should be understood as including a situation where each set is a part of a continuous fin arrangement, the first set comprising a part in which fin portions are aligned in a front to rear direction of the light unit and the second set comprising a part in which fin portions are aligned in a direction from top to bottom of the light unit 34.

[0044] As illustrated somewhat schematically in FIGS. 4 to 7, the light unit 34 is mounted in a housing 36 which defines an aperture 72 through which the front end 38 of the light unit 34 projects. Alternatively, the front end 38 of the light unit 34 may not project through the aperture but is aligned with the aperture 72 such that light emitted by the light unit 34 is able to pass through the aperture 72 to illuminate the target environment.

[0045] The housing 36 closely surrounds the light unit 34, at least proximal its front end 38. The indented portion 62 of the upper wall is spaced further from an interior surface of the housing 36 than the un-indented portions 64 either side of it and forms a port 73 through which air is able to flow into or out of the housing 36 through the first set of cooling fins 50.

[0046] The housing 36 is configured to constrain air to flow through both of the first and second sets of cooling fins 50, 52. In an embodiment, the housing 36 has a first wall 74 which extends proximal the side region of the light unit 34 where the first set of cooling fins 50 are located so as to be proximal to distal end surfaces 50a of the fins 50 in the first set of cooling fins 50. The housing also has a second wall 76 which extends proximal to the rear of the light unit 34 so as to be proximal to distal end surfaces 52a of the cooling fins in the second set of cooling fins 52. The first and second walls 74, 76 may be continuous with one another and can be shaped or profiled in various ways. In the present embodiment where the first set of cooling fins 50 are located on an upper part of the side region of the light unit 34, the first housing wall 74 is an upper wall. However, in other embodiments, the first set of cooling fins 50 are located on a lower part of the side region of the light unit 34 and the first housing wall 74 is a lower wall.

[0047] The housing also defines an air vent 78 through which air can pass between the interior of the housing 36 and the exterior of the housing. The air vent may 78 have a number of apertures 80 spaced apart across the width of the light unit as shown to allow for a free flow of air across the width of the light unit 34. The air vent 78 may be located in a lower wall 82 of the housing and may connect the interior of the housing 36 to the ambient environment external to the mobile machine to enable hot air to pass out of the housing to the exterior or cool fresh air to be drawn into the housing. The housing 36 may be defined by part of the peripheral edge region 32 of the roof section 26 and/or it may be defined within the peripheral edge region 32. In practice, the housing 36 may be at least partly defined by the bodywork which forms the peripheral edge region 32 of the roof section but may also be defined by dedicated housing components located within the peripheral edge region 32 or a combination of the two. The air vent 78 may be defined in a lower wall 82 which closes the peripheral edge region 32, for example.

[0048] The light unit 34 and the housing 36 cooperate to define an air flow path (indicated generally at 84) between the aperture 72 and the air vent 78 which includes the two sets of cooling fins 50, 52. More particularly, the air flow path 84 extends between the port 73 which is defined within the aperture 72 by the indented side region 62 of the light unit 34 and the air vent 78, passing through both the first and the second sets of cooling fins 50, 52.

[0049] Air is able to flow along the air flow path 84 in either direction depending on whether the air flow is generated due to convention or a ram air effect produced as the tractor 10 moves.

[0050] In certain embodiments, the aperture 72 is aligned with a direction of movement X of the tractor 10 so that when the tractor 1 moves in that direction, external air is forced in a ram air effect to enter the housing 36 through the port 73, flow through the first set of cooling fins 50, the second set of cooling fins 52, and out through the air vent 78. As the air passes over the cooling fins 50, 52, heat is transferred from the cooling fins to the air and the heated air exits the housing through the air vent 78. This air flow helps to keep the light unit 34 cool and is illustrated in FIG. 6, where the arrows 84a indicate a ram effect air flow in which relatively cool exterior air enters the housing 36 through port 73, is constrained to flow through the two sets of cooling fins 50, 52 by the housing, and exits through the air vent 78. In the embodiment illustrated in FIG. 1, the light unit 34 and aperture 72 face the front of the tractor 10 so that when the tractor moves in a forward direction X, air will be driven along the air flow path 84 by a ram air effect. In an alternative embodiment, the light unit 34 and aperture may face the rear of the vehicle so that a ram air effect is generated when the vehicle moves in reverse.

[0051] It will be appreciated that the light unit 34 and aperture 72 need not be aligned exactly parallel to the direction of movement for a ram air effect to be generated. For example, the light unit 34 and aperture 72 might be angled slightly off to one side. Provided that the light unit 34 and aperture 72 are aligned with a component of the direction of movement a ram air effect is possible. The quantity of the ram air effect is also dependent on the speed for movement of the tractor.

[0052] Where no ram air effect is generated, say because the tractor is stationary or because the light unit 34 and aperture 72 are not aligned with the direction of movement of the tractor 10, an air flow through the air flow path 84 can be generated by convection as illustrated in FIG. 7, where the arrows 84b indicate a convective air flow current. When the light unit 34 is in use, air surrounding the cooling fins 50, 52 is heated up and will tend to rise. The heated air flows along the flow path 84 to exit the housing through the port 73, which is uppermost in the embodiment shown in FIG. 7. Cooler fresh air is drawn into the housing 36 through the air vent 78. The convective air current flows from the air vent 78, through the second set of cooling fins 52, the first set of cooling fins 50, and out through the aperture 72 and helps to cool the light unit, even in the absence of a ram air effect.

[0053] FIGS. 8 and 9 illustrate in more detail an embodiment of a lighting arrangement 30 in accordance with an aspect of the disclosure, in which a number of light units 34 are mounted in a peripheral edge region 32 of a roof portion 26 of a tractor cab 18. As illustrated, the light units 34 are arranged about the peripheral edge region 32 with some along a forward facing part of the peripheral edge region 32 and some in a side facing part. Further light units 34 may be provided in a rear facing part of the peripheral edge region 32. Light units 34 can be positioned where required to illuminate the environment surrounding the tractor 10. Each light unit 34 is located within or adjacent an aperture 72 in a housing 36 which at least partially surrounds the light unit 24. In the embodiment as illustrated in FIG. 9, each housing 36 includes a first, upper wall 74 extending over an upper portion of the side wall region of the light unit 34 and a second, rear wall 76 which extends proximal the rear end of the light unit. The upper and rear walls 74, 76 constrain air to flow through both sets of cooling fins 50, 52 and help to define part of the air flow path 84. In a lower wall 86 of the peripheral edge region 32 is an air vent 78 through which air can enter or exit a chamber 88 formed in the peripheral edge region 32 behind and below the light unit 34 and housing 36. The housing 36 in this case can be considered an inner housing 36 which may have a lower wall 90 with apertures or vents through which air is able to pass between the interior of the inner housing 36 and the chamber 88. As shown, there may be several light units 34 and inner housings 36 associated with a single chamber 88 in the peripheral edge region of the roof. In alternative embodiments, the inner housing 36 may not have a lower wall 90, the lower wall 86 of the peripheral edge region forming the lower wall of the light unit housing, or there may be no lower wall 86 closing the peripheral edge region 32 of the roof section but a lower wall 90 of the inner housing. It will be appreciated that there are many ways in which a light unit 34 may be housed in the peripheral edge region which leads to a flow of air through the cooling fins 50, 52 due to convection or a ram-air effect in the manner described.

[0054] Providing a lighting arrangement 30 in which light units 34 are located in a peripheral edge region 32 of the roof portion 26 of the cab is advantageous as the elevated position provides a good location for the light units to illuminate the environment about the tractor 10. Typically, the roof portion 26 also houses various equipment for the tractor 10, such as an air filtration and HVAC system as well as wiring looms and a range of other equipment. It is an advantage of the lighting arrangement 30 according to the invention that it is not necessary to direct air from an air source, e.g. a fan, to each of the light units 34 to provide cooling since there is little space available to accommodate the necessary conduits and additional equipment required for this. It is a further advantage that the light units 34 are partially enclosed within the roof portion rather than being exposed above the roof portion where they may be more likely to be damaged and which increases the overall height of the tractor.

[0055] Whilst is often desirable to mount a light unit 34 high up in the roof section 26 of the cab, in certain circumstances it may also be desirable to mount a light unit 34 elsewhere on the tractor, say towards the front of the engine compartment to provide a front working light.

[0056] In some arrangements, it may be desirable to locate the air vent 78 above the light unit 34 and to provide the first set of cooling fins 50 on a lower part of the side region of the light unit 34. In this case, if the light unit 34 is aligned with a direction of movement of the tractor 10, a ram air effect would cause air to flow in through the port 73, through the first set of cooling fins, upwardly through the second set of cooling fins 52 at the rear of the light unit and exit through the air vent 78. A convective airflow 84b would be generated in the same direction when there is no ram air effect as air surrounding the cooling fins 50, 52 which is heated when the light unit is in use would rise to pass out of the air vent 78, with cooler fresh air being drawn in through the port 73, which in this embodiment is located below the light unit 34.

[0057] Whist embodiments of the disclosure have been described with reference to a lighting arrangement 30 for a tractor 10, it will be readily appreciated that such a lighting arrangement 30 can be adopted in other working machines including, without limitation, working machines used agriculture or construction and other tyres of vehicle, especially vehicles which are often used off-road and where the need for working lights arises.

[0058] All references cited herein are incorporated herein in their entireties. If there is a conflict between definitions herein and in an incorporated reference, the definition herein shall control.