Roll cage

Abstract

Aspects of the present invention relate to a roll cage 10 for a vehicle 100. The roll cage 10 comprises a plurality of discrete sections 14, 16, 18A, 18B, 20, 22 joined together by releasable connecto

Description

1-0 TECHNICAL FIELD The present disclosure relates to a roll cage for a vehicle. Aspects of the invention relate to a roll cage, to a 5 vehicle comprising a roll cage and to a method of assembling a roll cage. BACKGROUND It is known to provide a roll cage which forms a canopy over the passenger compartment of certain vehicles in order to protect the vehicle occupants in the event of a rollover situation. For example, roll cages are commonly 10 used in racing vehicles, off-road vehicles, ATVs, and sport utility vehicles for enhanced occupant protection. Typically, a roll cage is constructed as a welded tube structure. When it is desired to install a roll cage within the interior of motor vehicle, the tubes of the roll cage are generally passed through openings in the vehicle body and welded together in situ to form the roll cage. However, such arrangements can make it difficult to 15 install othertypes of equipment in the vehicle once the roll cage has been installed. To address this, it is known to install such equipment prior to the assembly of the roll cage. However, welding inside a vehicle without causing damage to interior components can be difficult and time-consuming and may necessitate repair of interior components after the roll cage is installed. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a roll cage, a vehicle comprising a roll cage, and a method of assembling a roll cage as claimed in the appended claims. Throughout the summary of the invention, description and claims the terms front, rear, left, right, upper and lower are defined with reference to their normal use in the description of a forward facing upright standing vehicle. It follows that features of the invention are described in relation to a vehicle such that, for example, front features are those closer to the front of the vehicle than rear features and upper features are those closer 30 to the top of the vehicle than lower features. According to an implementation there is provided a roll cage for a vehicle. The roll cage comprises a plurality of discrete sections joined together by releasable connectors. The plurality of discrete sections comprises a main canopy comprising first and second upright pillars on first and second sides of the main canopy and a 35 roof cross-member extending between upper ends of the first and second upright pillars. The plurality of discrete sections also comprises a rear brace structure extending rearward of the main canopy to reinforce the main canopy. The rear brace structure comprises a plurality of rear brace sections each being releasably connected to the main canopy by the releasable connectors. 40 Each of the plurality of discrete sections is formed prior to installation such that the entire section can be provided and installed as a single unit. The plurality of discrete sections may each comprise a plurality of structural components which are integrally formed, i.e. formed from a single continuous tubular component or from multiple structural components which are fixed (i.e. not releasably connected) together e.g. by welding, such that the entire section can be provided and installed as a single unit. 5 The rear brace structure being releasably connected to the main canopy can allow for easier removal of the rear brace structure to improve access behind the main canopy for installation or assembly of other vehicle components, such as an auxiliary fuel tank, into the space between the main canopy and the rear brace structure. 10 In addition, having a plurality of rear brace sections, as opposed to a single rear brace section, can make it possible to temporarily remove only part of the rear brace structure to enable access to the region immediately behind the main canopy, for example to install additional equipment such as an auxiliary fuel tank. The provision of multiple rear brace structure sections can also make it to be easier for removal and re-installation of the entire rear brace structure since each rear brace section is smaller (and therefore easier to move within 15 the vehicle body) than the rear brace structure as a whole. This plurality of rear brace sections arrangement can also provide a more flexible configuration by which the rear brace structure can be adapted according to the desired roll cage strength, vehicle weight, and cargo load space for a given application by the addition or removal of structural components to or from the overall rear brace structure. It will be understood that the term “releasably connected” means that the respective sections can be coupled or removed from each other without causing damage to either section. Similarly, a “releasable connector” is any type of connection which allows the respective sections to be coupled or removed from each other without causing damage to either section. 25 It will be understood that the term “fixed together” or “not releasably connected” means that the respective sections cannot be coupled or removed from each other without causing damage to either section. Similarly, multiple structural components being fixed together can be achieved by any type of connection or connection means which does not allow the respective sections to be coupled or removed from each other without causing damage to either section. 30 The roll cage is preferably an interior roll cage. That is, a roll cage which is configured to be installed within the interior of the vehicle, rather than an exterior roll cage configured to be installed outside of the vehicle body. Optionally, the plurality of rear brace sections comprises first and second rear brace sections releasably 35 connected to first and second sides of the main canopy by the releasable connectors. Such first and second rear brace sections provide rear brace support on both sides of the main canopy. Optionally, the first and second rear brace sections each comprise a rear diagonal strut which is releasably 40 connected to the main canopy proximal to a centre point of the roof cross-member, and which extends diagonally rearwards and laterally outwards from the roof cross-member to a respective rear chassis mounting 1-0 1-0 point at a base of the rear brace structure, such that the rear diagonal struts of the first and second rear brace sections collectively define an inverted V-configuration. Typically, the rear brace structure of a roll cage is provided in an X-configuration. However, having an inverted 5 V-configuration instead provides a larger space laterally between the rear diagonal struts at a base end of the rear brace structure, which can be used for storage space. In particular, such an inverted V-configuration has been found to be suitable for storing two spare wheels at least partially within the space envelope of the roll cage. 10 Optionally, the roll cage comprises a rear lateral cross brace releasably connected to and extending between the rear diagonal struts of the first and second rear brace sections partway along the length of the rear diagonal struts. Such a rear lateral cross brace can be used to provide a longitudinal support for items stored between the rear 15 diagonal struts. For example, as a longitudinal support for spare wheels which are arranged one in front of the other in a longitudinal direction of the roll cage (i.e. in a configuration in which a rotational axis of the spare wheels is parallel to a longitudinal axis of the roll cage). In addition, because the rear lateral cross brace is releasably connected to the rear diagonal struts, it can be removed when needed (e.g. for providing a larger unobstructed storage space between the rear diagonal struts). This may be useful, for example, when storing spare wheels arranged side-by-side in a lateral direction of the roll cage (i.e. in a configuration in which a rotational axis of the spare wheels is transverse to a longitudinal axis of the roll cage). In other words, removal of the rear lateral cross brace enables spare wheels to be stored side-by-side between the rear diagonal struts for easier selection of a desired spare wheel. 25 Optionally, the rear brace structure comprises a fuel tank mount tray releasably connected to the first and second rear brace sections, wherein the fuel tank mount tray is configured to act as a lateral brace. Such a fuel tank mount tray provides dual functions of mounting a fuel tank or components thereof, whilst also 30 increasing the integrity of the rear brace structure. In this way, an efficient use of components which minimises weight of the roll cage and fuel tank mounting structure is provided. Optionally, the fuel tank mount tray is releasably connected to the rear diagonal struts. 35 The fuel tank mount tray being connected to the rear diagonal struts converts the inverted V-configuration of the rear diagonal struts into an A-configuration, which increases the strength of the rear diagonal strut configuration. Optionally, the first and second rear brace sections each comprise an upper backstay which is releasably 40 connected to the main canopy proximal to an upper end of the respective upright pillar, and which extends rearwards and downwards to a respective rear chassis mounting point at a base of the rear brace structure. Such upper backstays provide the rear brace structure with increased integrity. 1-0 Optionally, the first and second rear brace sections each comprise a lower backstay which is releasably 5 connected to the main canopy proximal to a lower end of the respective upright pillar, and which extends rearwards from the lower end of the upright pillar towards a respective rear chassis mounting point at a base of the rear brace structure. Such lower backstays provide the rear brace structure with increased integrity. 10 Optionally, the first and second rear brace sections each comprise a mid backstay which is releasably connected to the main canopy between upper and lower ends of the respective upright pillar, and which extends backwards from the upright pillar towards a respective rear chassis mounting point at a base of the rear brace structure. 15 Such mid backstays provide the rear brace structure with increased integrity. The upper, lower and mid backstays may be integrally joined to each other, for example in the region of the rear chassis mounting point, such that each of the first and second rear brace sections can be installed as a single unit. Optionally, the releasable connectors comprise overlap joints. Such overlap joints provide a simple means for connecting the roll cage sections together. In addition, such 25 overlap joints are known to be robust enough to provide the overall roll cage structure with sufficient strength. In alternative embodiments, the releasable connectors comprise bolted sleeves. Optionally, each of the plurality of discrete sections is substantially planar. 30 Each section being substantially planar allows the sections to be more easily stacked prior to assembly (i.e. prior to joining together via the releasable connectors) to provide simpler storage and / or transport. In other words, this allows the roll cage to be palletised prior to assembly. In this context, the term “substantially planar” means that the height of the tallest section of the roll cage is no 35 greater than approximately 45cm if laid flat on the ground prior to assembly of the roll cage. Optionally, the roll cage further comprises first and second side sections releasably connected to the main canopy, wherein each side section comprises an A-pillar and at least one longitudinal member extending between the A-pillar and the main canopy and releasably connected to the main canopy. 40 1-0 Optionally, the at least one longitudinal member of each side sections comprises a side roof bar and a door barwhich, together with the A-pillar and main canopy, define a door opening. The first and second side sections provide a longitudinal support to the main canopy and provide passengers 5 located forward of the main canopy with increased protection from side impacts. Optionally, the roll cage further comprises a roof section releasably connected to the first and second side sections and the main canopy section; optionally, wherein the roof section comprises a front roof crossmember releasably connected to the first and second side sections proximal to upper ends of the A-pillars and 10 one or more longitudinal roof braces extending from the front roof cross-member of the roof section towards the roof cross-member of the main canopy. The roof section provides the roll cage with increased longitudinal and lateral integrity, and provides passengers with increased protection. 15 According to another implementation, there is provided a vehicle (100) comprising a roll cage as disclosed herein. Such a vehicle benefits from the advantages of the roll cage outlined above. According to another implementation, there is provided a method of assembling a roll cage within a vehicle body. The method may comprise: (a) providing a vehicle body having one or more openings; (b) inserting a plurality of discrete roll cage sections through the one or more openings, wherein the 25 plurality of discrete roll cage sections comprises: a main canopy comprising first and second upright pillars and a roof cross-member extending between upper ends of the first and second upright pillars; and a rear brace structure comprising a plurality of rear brace sections each being configured to be releasably connected to the main canopy and to extend rearward of the main canopy to reinforce the main canopy; and (c) joining the plurality of discrete roll cage sections together by releasable connectors. 30 Such a method enables installation of the roll cage within an existing vehicle body (e.g. a monocoque shell) without having to weld the roll cage in situ, repaint, or remove and then reinstall electrical components. Furthermore, releasably connecting the rear brace structure in the form of a plurality of rear brace sections to 35 the main canopy allows easier removal of the rear brace structure to improve access behind the main canopy for installation or assembly of other vehicle components, such as an auxiliary fuel tank, into the space between the main canopy and the rear brace structure. Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples 40 and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. 01 04 25 That is, all embodiments and / or features of any embodiment can be combined in anyway and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a roll cage according to an embodiment; Figure 2 shows a front view of the roll cage of Figure 1 with a rear bulkhead installed behind a main canopy of the roll cage; Figure 3 shows a rear view of the roll cage of Figures 1 and 2 with a rear bulkhead and fuel tank installed behind the main canopy of the roll cage; Figure 4 shows a side view of the roll cage of Figures 1 to 3; Figure 5 shows a plan view of the roll cage of Figures 1 to 4; Figure 6 shows a rear perspective view of the roll cage of Figures 1 to 5; Figure 7 shows plan view of the roll cage of Figures 1 to 6 with a spare wheel adjacent a rear lateral cross brace of the roll cage; Figure 8 shows a plan view of the roll cage of Figures 1 to 7 with the rear lateral cross brace and fuel tank removed and spare wheels located between rear brace sections of the roll cage; Figure 9 shows a vehicle in accordance with an embodiment of the invention; Figure 10 shows a block diagram of a method of assembling the roll cage of Figures 1 to 8; and 35 Figure 11 shows a block diagram of a method of retrospective installing a bulkhead and / or fuel tank within a footprint of the roll cage of Figures 1 to 8. DETAILED DESCRIPTION A roll cage in accordance with an embodiment of the present invention is described herein with reference to 40 the accompanying Figures 1 to 8. As shown in Figure 9, the roll cage 10 is installed inside a vehicle 100. In other words, the roll cage 10 is an internal roll cage. 1-0 With reference to Figures 1 to 8, there is illustrated a roll cage 10 for a vehicle. The roll cage 10 includes a plurality of discrete sections joined together by releasable connectors 12. Each discrete section may comprise a plurality of structural components which are integrally formed, i.e. formed from a single continuous tubular component or from multiple structural components which are fixed together e.g. by welding, such that the entire 5 section can be provided and installed as a single unit. The plurality of discrete sections includes: a main canopy 14, and a rear brace structure 16 releasably connected to the main canopy 14. The main canopy 14 has first and second upright pillars 14A, 14B on first and second sides of the main canopy 14 and a roof cross-member 14C extending between upper ends of the first and second upright pillars 14A, 10 14B. The main canopy 14 may be provided as a single section in which the upright pillars 14A, 14B and the roof cross-member 14C are integrally formed, i.e. formed from a single continuous tubular component or from multiple components which are fixed together, e.g. by welding. The rear brace structure 16 extends rearward of the main canopy 14 to reinforce the main canopy 14. It will be understood that the term “fixed together” or “not releasably connected" means that the respective sections cannot be coupled or removed from each other 15 without causing damage to either section. Similarly, multiple structural components being fixed together can be achieved by any type of connection or connection means which does not allow the respective sections to be coupled or removed from each other without causing damage to either section. In the illustrated embodiment, the plurality of discrete sections also includes: first and second side sections 18A, 18B releasably connected to the main canopy 14; a roof section 20 releasably connected to the first and second side sections 18A, 18B and to the main canopy 14; and one or more front sections 22 releasably connected to the first and second side sections 18A, 18B. It will be understood that the term “releasably connected” means that the respective sections can be coupled or removed from each other without causing damage to either section. Similarly, a “releasable connector” 12 is any type of connection which allows the 25 respective sections to be coupled or removed from each other without causing damage to either section. Having a plurality of discrete sections 14, 16, 18A, 18B, 20, 22 joined together by releasable connectors 12 can facilitate installation of the roll cage 10 within an existing vehicle body (e.g. a monocoque shell) by passing the sections 14, 16, 18A, 18B, 20, 22 through door openings and releasably connecting the sections together 30 without having to weld the roll cage 10 in situ, repaint, or remove and then reinstall electrical components. In addition, having a plurality of discrete sections 14, 16, 18A, 18B, 20, 22 joined together by releasable connectors 12 can also allow the roll cage 10 to be palletised (that is stacked or stored onto a pallet) for easier transport and storage prior to installation. Furthermore, the rear brace structure 16 being releasably connected to the main canopy 14 allows removal of the rear brace structure 16 to improve access behind the main canopy 35 14. For example, to facilitate the installation or assembly of other vehicle components, such as an auxiliary fuel tank 104 or fuel tank 104, into the space between the main canopy 14 and the rear brace structure 16. In the illustrated embodiment, each of the plurality of discrete sections 14,16,18A, 18B, 20, 22 is substantially planar. Each section being substantially planar allows the sections 14,16,18A, 18B, 20, 22 to be more easily 40 stacked prior to assembly (i.e. prior to joining together via the releasable connectors 12) to provide simpler storage and / or transport. This can facilitate palletising ofthe roll cage 10 priorto assembly. In this context, the 1-0 term “substantially planar” means that, when a given section is laid flat, it has a maximum height of less than 60cm, preferably less than 50cm, most preferably less than 45cm. In some embodiments, some of the plurality of discrete sections 14, 16, 18A, 18B, 20, 22 are substantially 5 planar, while some of the plurality of discrete sections 14, 16, 18A, 18B, 20, 22 are not substantially planar. This may still allow the sections 14, 16, 18A, 18B, 20, 22 to be stacked prior to assembly for simpler storage and / or transport. In such embodiments, the sections which are not substantially planar may fit inside empty space within or around the substantially planar sections. 10 In the illustrated embodiment, as best seen in Figure 2, the main canopy 14 is strengthened by an X-shaped main canopy brace structure which includes two diagonal main canopy braces 14D, 14E which each extend from a lower end of one of the upright pillars 14A, 14B to an upper end of the other upright pillar 14A, 14B. The diagonal main canopy braces 14D, 14E are optionally strengthened by webbing 14F. The main canopy 14 also includes lateral main canopy braces 14G, 14H which extend from the upright pillars 14A, 14B to a 15 crossover point at the centre of the two diagonal main canopy braces 14D, 14E. The main canopy 14 also includes a bottom main canopy brace arrangement 14J for supporting a base structure of a rear bulkhead 102 located behind the main canopy 14. As best seen in Figures 3 to 6, the rear brace structure 16 is formed from a plurality of structural members extending rearward from various connection points on the main canopy 14 towards rear chassis mounting points 25 at the rear of the roll cage 10. The rear brace structure 16 includes a plurality of rear brace sections 24A, 24B which are releasably connected to the main canopy by releasable connectors 12. In the illustrated embodiment, the rear brace structure 16 has first and second rear brace sections 24A, 24B releasably connected to the first and second sides of the main canopy 14 by the releasable connectors 12. Having a 25 plurality of rear brace sections (e.g. two rear brace sections 24A, 24B), as opposed to a single rear brace section, can make it easier to remove and re-install the rear brace structure 16, since each rear brace section 24A, 24B is smaller (and therefore easier to move within a vehicle body) than the rear brace structure 16 as a whole. It also can also enable access to the region behind the main canopy by the removal of only one side of the rear brace structure 16. In alternative embodiments, the rear brace structure 16 consists of greater than 30 two sections. In the illustrated embodiment, each of the rear brace sections 24A, 24B has an upper backstay 26A, 26B, a lower backstay 30A, 30B, and a mid-backstay 36A, 36B. 35 The upper backstays 26A, 26B are releasably connected to the main canopy 14 proximal to an upper end of the respective upright pillar 14A, 14B. The upper backstays 26A, 26B each extend rearwards and downwards to the rear chassis mounting point 25 at a base of the rear brace structure 16. The lower backstays 30A, 30B are releasably connected to the main canopy 14 proximal to a lower end of the 40 respective upright pillar 14A, 14B. The lower backstays 30A, 30B each extend rearwards from the lower end of the respective upright pillar 14A, 14B towards the rear chassis mounting point 25. In the illustrated 1-0 embodiment, the lower backstays 30A, 30B are bent or curved so that they include a first portion 32A, 32B which extends diagonally rearwards and inwards from the respective upright pillar 14A, 14B and a second portion 34A, 34B which extends rearwards to the rear chassis mounting point 25. In alternative embodiments, the lower backstays 30A, 30B are straight. 5 The mid-backstays 36A, 36B are releasably connected to the main canopy 14 between upper and lower ends of the respective upright pillar 14A, 14B. The mid backstays 36A, 36B each extend rearwards from the respective upright pillar 14A, 14B towards the rear chassis mounting points 25. 10 In the illustrated embodiment, each of the rear brace sections 24A, 24B also has a rear diagonal strut 28A, 28B which is releasably connected to the main canopy 14 proximal to a centre point of the roof cross-member 14C. The rear diagonal struts 28A, 28B each extend diagonally rearwards and laterally outwards from the roof cross-member 14C to the respective rear chassis mounting point 25, such that the rear diagonal struts 28A, 28B of the first and second brace sections 24A, 24B collectively define an inverted V-configuration. Having an 15 inverted V-configuration, instead of a typical X-configuration, provides a largerspace laterally between the rear diagonal struts 28A, 28B towards the base of the rear brace structure 16, which can be used for storage space. For example, such an inverted V-configuration has been found to be suitable for storing spare wheels W1, W2 at least partially within the space envelope of the roll cage, as illustrated in Figures 7 and 8. In the illustrated embodiment, the upper, lower and mid backstays 26A, 26B, 30A, 30B, 36A, 36B and the rear diagonal struts 28A, 28B are integrally joined to each other in the region of the rear chassis mounting point 25, such that each of the first and second rear brace sections 24A, 24B can be installed as a single unit. In alternative embodiments, one or more of the upper, lower and mid backstays 26A, 26B, 30A, 30B, 36A, 36B and the rear diagonal struts 28A, 28B may be releasably connected together. 25 In the illustrated embodiment, the rear brace structure 16 has a fuel tank mount tray 38 extending laterally between and releasably connected to the first and second rear brace sections 24A, 24B (see Figures 3, 5 and 6). In this way, the fuel tank mount tray 38 is configured to act as a lateral brace, which increases the integrity of the rear brace structure 16. In particular, the fuel tank mount tray 38 is releasably connected to and extends 30 between the rear diagonal struts 28A, 28B part way along the length of the rear diagonal struts 28A, 28B. This converts the inverted V-configuration defined by the rear diagonal struts 28A, 28B into an A-configuration, which can increase the strength and rigidity of the rear brace structure 16. The fuel tank mount tray 38 is also configured for mounting a fuel tank 104 or components thereof, as illustrated 35 in Figures 5, 6 and 7. In this way, the fuel tank mount tray 38 provides dual functions of mounting the fuel tank 104 and increasing the rigidity of the rear brace structure 16. This can help to minimise the overall weight of the roll cage 10 and mounting structure for the fuel tank 104. The rear brace structure 16 of the roll cage 10 also includes an optional rear lateral cross brace 42 releasably 40 connected to and extending between the rear diagonal struts 28A, 28B of the first and second rear brace sections 24A, 24B part way along the length of the rear diagonal struts 28A, 28B. In particular, the rear lateral 1-0 cross brace 42 is releasably connected to the rear diagonal struts 28A, 28B below the fuel tank mount tray 38. Such a rear lateral cross brace 42 can be used to provide a longitudinal support or brace for items stored between the rear diagonal struts 28A, 28B. For example, as illustrated in Figure 7, the rear lateral cross brace 42 can be used as a longitudinal support for spare wheels W1, W2 which are arranged one in front of the other 5 in a longitudinal direction of the roll cage 10 (i.e. in a configuration in which a rotational axis of the spare wheels W1, W2 is parallel to a longitudinal axis of the roll cage 10). This can help to limit inadvertent movement of the spare wheels during operation of the vehicle. The rear lateral cross brace 42 can also be used as a longitudinal support or brace for the fuel tank 104 illustrated in Figure 7, which is located on an opposing side of the rear lateral cross brace 42 to the spare wheels W1, \N2. 10 In addition, because the rear lateral cross brace 42 is releasably connected to the rear diagonal struts 28A, 28B, it can be removed when needed (e.g. for providing a larger unobstructed storage space between the rear diagonal struts 28A, 28B). This may be useful, for example, when storing spare wheels W1, W2 arranged side-by-side in a lateral direction of the roll cage 10, as illustrated in Figure 8 (i.e. in a configuration in which a 15 rotational axis of the spare wheels W1, W2 is transverse to a longitudinal axis of the roll cage 10). In other words, removal of the rear lateral cross brace 42 enables spare wheels W1, W2 to be stored side-by-side between the rear diagonal struts 28A, 28B, as illustrated in Figure 8, for easier selection of a desired spare wheel W1, W2. In the configuration illustrated in Figure 8, there is no fuel tank 104, which allows the spare wheels W1, W2 to be moved forwards into a space that could otherwise be occupied by the fuel tank 104. In the illustrated embodiment, the fuel tank mount tray 38 and the rear lateral cross brace 42 are releasably connected to the rear diagonal struts via a bolted connection which passes through lugs projecting from the rear diagonal struts 28A, 28B. In alternative embodiments, any suitable type of releasable connection may be used. 25 In the illustrated embodiment, the releasable connectors 12 between the plurality of discrete sections 14, 16, 18A, 18B, 20, 22 are overlap joints. It will be understood that the term “overlap joint” refers to an arrangement in which the respective sections 14, 16, 18A, 18B, 20, 22 include overlapping abutment surfaces and one or more releasable fasteners (e.g. bolts) are provided through the overlapping abutment surfaces in order to 30 releasably connect the respective sections 14, 16, 18A, 18B, 20, 22. Overlap joints are known to be robust enough to provide the overall roll cage structure 10 with sufficient strength. In alternative embodiments, the releasable connectors 12 between the plurality of discrete sections 14,16,18A, 18B, 20,22 are bolted sleeves, otherwise referred to as bolt in sleeves, bolted sleeve couplings or shaft couplings, which are releasable connectors comprising a centre sleeve configured to overlay the respective sections 14, 16, 18A, 18B, 20, 22 35 and a plurality of bolts or known similar releasable fasteners. As illustrated in Figure 4, each side section 18A, 18B may include an A-pillar 44 and at least one longitudinal member 46A, 46B, 46C extending between the A-pillar 44 and the main canopy 14 and releasably connected to the main canopy 14. Such first and second side sections 18A, 18B provide a longitudinal support to the main 40 canopy 14 and provide passengers located forward of the main canopy 14 with increased protection from side 1-0 impacts. In the illustrated embodiment, each side section 18A, 18B includes a side roof bar 46A and a door bar46B, 46C which, together with the A-pillar 44 and main canopy 14, define a door opening 48. In the illustrated embodiment, there are two door bars 46B, 46C forming an approximately X-shaped 5 configuration with a webbing 50 therebetween, which provides increased integrity. The side roof bar 46A is releasably connected to the main canopy 14 proximal to an upper end of the respective upright pillar 14A, 14B. The lower door bar 46C is releasably connected to the main canopy 14 proximal to a lower end of the respective upright pillar 14A, 14B. The upper door bar 46B is releasably connected to the main canopy 14 at a point between the lower and upper ends of the respective upright pillar 14A. 10 In the illustrated embodiment, the A-pillars 44 have an approximately triangular shape with a bent or curved portion 44A and a straight supporting strut 44B. Webbing 52 is provided between the bent portion 44A and the straight supporting strut 44B. 15 As illustrated in Figure 5, the roof section 20 may have a front roof cross-member 54 releasably connected to the first and second side sections 18A, 18B proximal to upper ends of the A-pillars 44. The roof section 20 may also have two longitudinal roof braces 56A, 56B extending from the front roof cross-member 54 towards the roof cross-member 14C of the main canopy 14. In the illustrated embodiment, the longitudinal roof braces 56A, 56B are each releasably connected to the main canopy 14 proximal to a centre point of the roof cross-member 14C of the main canopy 14 (e.g. just to either side of the centre point respectively), and the longitudinal roof braces 56A, 56B diverge sideways towards the front roof cross-member 54 of the roof section 20. In alternative embodiments, a different longitudinal brace configuration is provided. As illustrated in Figures 1 and 2, the one or more front sections 22 may include a dash bar 58 which extends between the A-pillars 44 beneath the intended location of the windscreen or windshield. The one or more front sections 22 may also include a mounting structure 60 for mounting dashboard components (e.g. HVAC units, dashboard, steering wheel, etc.). The mounting structure 60 may extend the full distance between the A-pillars 30 44. Such front sections 58, 60 can provide further lateral support to the first and second side sections 18A, 18B and provide passengers located behind the front sections 58, 60 with increased protection from frontal impacts. In addition to increasing integrity of the roll cage 10, the mounting structure 60 also provides a second function of allowing for the fixation of dashboard components in an appropriate location. 35 The illustrated mounting structure 60 includes a cross bar 62 and two legs 64 which extend downwards from the cross bar 62 towards a base of the roll cage 10. As well as the rear chassis mounting points 25 at the base of the rear brace structure 16, the roll cage 10 also includes: main canopy chassis mounting points 25 at a base of the upright pillars 14A, 14B of the main canopy 40 14; front chassis mounting points 25 at a base of the A-pillars 44 of the first and second side sections 18A, 18B; and centre chassis mounting points 25 at a base of the legs 64 of the mounting structure 60. 1-0 Figure 9 illustrates a vehicle 100 according to an embodiment of the present invention. The vehicle 100 comprises a roll cage 10 as illustrated in Figures 1 to 8. 5 In some embodiments, the vehicle 100 includes a rear bulkhead 102 within the footprint of the roll cage 10. For example, as illustrated in Figures 2 to 7, a rear bulkhead 102 may be provided adjacent to and behind the main canopy 14. It will be understood that the rear brace structure 16 being releasably connected to the main canopy 14 may make it easier to retrospectively fit such a rear bulkhead 102, since the rear brace section 16 can be removed, the rear bulkhead 102 installed and then the rear brace structure 16 re-installed. 10 In some embodiments, the vehicle 100 includes a fuel tank 104 within the footprint of the roll cage 10. For example, as illustrated in Figures 3 to 7, an auxiliary fuel tank 104 may be provided adjacent to and behind the rear bulkhead 102 and within a space between the rear brace structure 16 and the bulkhead 102. It will be understood that the rear brace structure 16 being releasably connected to the main canopy 14 may make it 15 easier to retrospectively fit such a fuel tank 104, since all or part of the rear brace section 16 can be temporarily removed, the fuel tank 104 installed and then the rear brace structure 16 re-installed. Referring now to Figure 10, a method of assembling the roll cage 10 of Figures 1 to 8 within a vehicle body is indicated at 200. The method 200 includes the following steps. At step 210, providing a vehicle body (e.g. a monocoque) having one or more openings (e.g. door openings 48 and / or boot / trunk openings). At step 220, inserting a plurality of discrete roll cage sections through the one or more openings, wherein the plurality of discrete roll cage sections comprises: a main canopy 14 comprising first and second upright pillars 14A, 14B and a roof cross-member 14C extending between upper ends of the firstand second upright pillars 14A, 14B; and a rear brace structure 16 configured to be releasably connected to the main canopy 14 and to extend 25 rearward of the main canopy 14 to reinforce the main canopy. At step 230, joining the plurality of discrete roll cage sections 14, 16 together by the releasable connectors 12. In some embodiments, the plurality of discrete roll cage sections also includes first and second side sections 18A, 18B, a roof section 20 and / or one or more front sections 22, as has been described above. 30 It will be understood that steps 220 and 230 may be carried out iteratively. In other words, instead of inserting all of the roll cage sections 14, 16, 18A, 18B, 20, 22 through the openings and then joining together, the roll cage sections 14, 16,18A, 18B, 20, 22 may be inserted and joined to the respective roll cage sections 14,16, 18A, 18B, 20, 22 one at a time. 35 For example, the method 200 may be carried out as follows. Firstly, the main canopy 14 may be inserted through a door opening. The first and second rear brace sections 24A, 24B may then be inserted through a boot opening and joined together with the main canopy 14 by releasable connectors 12. The first and second side sections 18A, 18B may then be inserted through a door opening and joined together with the main canopy 40 14 by releasable connectors 12. The roof section 20 may then be inserted through a door opening and joined together with the main canopy 14 and with the first and second side sections 18A, 18B by the releasable 1-0 connectors 12. Finally, the one or more front sections 22 may be inserted through a door opening and joined together with the first and second side sections 18A, 18B by releasable connectors 12. The method 200 also includes step 240 of attaching the respective sections 14, 16, 18A, 18B, 20, 22 to the 5 vehicle body via the mounting points 25 (e.g. by passing bolts through the mounting points 25 and / or welding the mounting points 25 to the vehicle body). This step may be carried out once the roll cage 10 is fully assembled, or iteratively once each section 14,16, 18A, 18B having a mounting point 25 is inserted through the openings. 10 In embodiments where a rear bulkhead 102 and / or auxiliary fuel tank 104 are provided behind the main canopy 14 and within the footprint of the rear brace structure 16, the method 200 may include installing the rear bulkhead 102 and / or auxiliary fuel tank 104 prior to inserting the first and second rear brace sections 24A, 24B through the boot opening and joining the rear brace sections 24A, 24B together with the main canopy 14 by releasable connectors 12. 15 A rear bulkhead 102 and / or auxiliary fuel tank 104 may also be retrofitted to an existing vehicle including the roll cage 10 of Figures 1 to 8. For example, Figure 11 illustrates a method 300 of retrofitting a rear bulkhead 102 and / or auxiliary fuel tank 104 to a vehicle including the roll cage 10 described above. The method 300 includes the following steps: At step 310, providing a vehicle including the roll cage 10; At step 320, removing at least part of the rear brace structure 16 from the vehicle (e.g. by releasing the releasable connectors 12 between the rear brace structure 16 and the main canopy 14 and / or releasing the mounting points 25 of the rear brace structure 16 from a body of the vehicle); At step 330, installing a rear bulkhead 102 and / or an auxiliary fuel tank 104 behind the main 25 canopy 14; and At step 340, re-installing the rear brace structure 16 in the vehicle (e.g. by re-joining the releasable connectors 12 between the rear brace structure 16 and the main canopy 14 and / or attaching the mounting points 25 of the rear brace structure 16 to a body of the vehicle). 30 It will be understood that such a method 300 may be carried out on any type of roll cage 10 which has a rear brace structure releasably coupled to a main canopy 14. In other words, the configuration of other components of the roll cage 10 described above (e.g. the side sections 18A, 18B, roof section 20 and front sections 22) may differ to the configuration shown in Figures 1 to 8. 35 It will be appreciated that various changes and modifications can be made to the present disclosed examples without departing from the scope of the present application. Whilst endeavouring in the foregoing specification to draw attention to those features believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not particular emphasis has been placed thereon. 40

Claims

1-01. A roll cage for a vehicle, the roll cage comprising a plurality of discrete sections joined together by releasable connectors, wherein the plurality of discrete sections comprises:5 a main canopy comprising first and second upright pillars on first and second sides of the maincanopy and a roof cross-member extending between upper ends of the first and second upright pillars; anda rear brace structure extending rearward of the main canopy to reinforce the main canopy, wherein the rear brace structure comprises a plurality of rear brace sections each being releasably connected to the main canopy by the releasable connectors,10 wherein the plurality of rear brace sections comprises first and second rear brace sections releasablyconnected to first and second sides of the main canopy by the releasable connectors, andwherein the first and second rear brace sections each comprise a rear diagonal strut which is releasably connected to the main canopy proximal to a centre point of the roof cross-member, and which extends diagonally rearwards and laterally outwards from the roof cross-member to a respective rear chassis 15 mounting point at a base of the rear brace structure, such that the rear diagonal struts of the first and second rear brace sections collectively define an inverted V-configuration.

2. The roll cage of claim 1, comprising a rear lateral cross brace releasably connected to and extending between the rear diagonal struts of the first and second rear brace sections part way along the length of the rear diagonal struts.

3. The roll cage of claim 1 or claim 2, wherein the rear brace structure comprises a fuel tank mount tray releasably connected to the first and second rear brace sections, wherein the fuel tank mount tray is configured to act as a lateral brace.

254. The roll cage of claim 3, wherein the fuel tank mount tray is releasably connected to the rear diagonal struts.

5. The roll cage of any preceding claim, wherein the first and second rear brace sections each comprise 30 an upper backstay which is releasably connected to the main canopy proximal to an upper end of the respective upright pillar, and which extends rearwards and downwards to a respective rear chassis mounting point at a base of the rear brace structure.

6. The roll cage of any preceding claim, wherein the first and second rear brace sections each comprise 35 a lower backstay which is releasably connected to the main canopy proximal to a lower end of the respective upright pillar, and which extends rearwards from the lower end of the upright pillar towards a respective rear chassis mounting point at a base of the rear brace structure.

7. The roll cage of any preceding claim, wherein the first and second rear brace sections each comprise 40 a mid backstay which is releasably connected to the main canopy between upper and lower ends of the1-0respective upright pillar, and which extends backwards from the upright pillartowards a respective rear chassis mounting point at a base of the rear brace structure.

8. The roll cage of any preceding claim, wherein the releasable connectors comprise overlap joints.

59. The roll cage of any preceding claim, wherein each of the plurality of discrete sections is substantially planar.

10. The roll cage of any preceding claim, further comprising first and second side sections releasably 10 connected to the main canopy, wherein each side section comprises an A-pillar and at least one longitudinal member extending between the A-pillar and the main canopy and releasably connected to the main canopy.

11. The roll cage of claim 10, wherein the at least one longitudinal member of each side section comprises a side roof bar and a door bar which, together with the A-pillar and main canopy, define a door 15 opening.

12. The roll cage of claim 10 or claim 11, further comprising a roof section releasably connected to the first and second side sections and the main canopy.

13. The roll cage of claim 12, wherein the roof section comprises a front roof cross-member releasably connected to the first and second side sections proximal to upper ends of the A-pillars and one or more longitudinal roof braces extending from the front roof cross-member of the roof section towards the roof crossmember of the main canopy.25 14. A vehicle comprising the roll cage of any preceding claim.

15. A method of assembling a roll cage within a vehicle body, the method comprising:(a) providing a vehicle body having one or more openings;(b) inserting a plurality of discrete roll cage sections through the one or more openings, wherein the30 plurality of discrete roll cage sections comprises: a main canopy comprising first and second upright pillars and a roof cross-member extending between upper ends of the first and second upright pillars; and a rear brace structure comprising a plurality of rear brace sections each being configured to be releasably connected to the main canopy and to extend rearward of the main canopy to reinforce the main canopy, wherein the plurality of rear brace sections comprises first and second rear brace sections releasably35 connected to first and second sides of the main canopy by the releasable connectors, and wherein the first and second rear brace sections each comprise a rear diagonal strut which is releasably connected to the main canopy proximal to a centre point of the roof cross-member, and which extends diagonally rearwards and laterally outwards from the roof cross-member to a respective rear chassis mounting point at a base of the rear brace structure, such that the rear diagonal struts of the first and second rear brace sections40 collectively define an inverted V-configuration; and(c) joining the plurality of discrete roll cage sections together by releasable connectors.

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