Coupling device, coupling arrangement and coupling system

Abstract

A modular coupling device for connecting elongate box section beams for use in e.g. staging framework roof, the device having a base plate 11, a first wall 12 extending from the base plate, a second wall 13 extending from the base plate, a channel 15 defined between the first wall and the second wall for receive a first portion of a complementary coupling device, and a capping piece 14a-d extending from the base plate. The coupling device may be a clevis with walls and U shaped channel forming interlocking fingers for receiving complementary shaped walls of another coupling device. The capping piece may be a flat plate like member 14a (Fig. 1) for receipt in a complementary aperture of a bridging piece 43 (Fig. 4A), or a protruding cuboid for receipt in the socket like end of a box section, including recesses 143a,b matching seams inside box sections. Locking pins (54, Fig 5A-D) may be extendable through aligned apertures 16 in connecting members, beams and bridging pieces. Also claimed is a system including two coupling devices, and a system including a bridging piece for joining multiple coupling devices / beam ends.

Description

FIELD OF THE DISCLOSURE Embodiments of the present invention relate generally to components for modular structures and to structures constructed using such components. BACKGROUND Modular structures are structures that comprise a number of components that are pieced together in a repeat, sequential nature to provide an overall structure. The repetitive nature of the structures allows for them to be scaled to size. Such structures can be permanent, semi-permanent or temporary. Temporary structures may be assembled to be used for a limited amount of time and then disassembled again. Modular structures are often faster and easier to assemble compared with other (e.g. non-modular) structures. In some circumstances (e.g. temporary structures), modular structures may also be disassembled in a quicker and more straightforward manner compared with other (e.g. non-modular) structures, such that they may be reassembled, i.e. the components may be able to be reused after disassembly. It is therefore desirable that the design of a modular structure and the components of a modular structure allows for the assembly and / or disassembly of the structure to be straightforward, quick, efficient and / or not overly labour intensive, so as to maximise the benefits of modular structures, e.g. over other (non-modular) structures. For a temporary structure, it may also be desirable for the components of the structure to be connected and coupled in a non-permanent way so that the structure can be disassembled. Transportation of a modular structure (e.g. from a location where the structure is produced or stored to the site at which the structure is to be assembled) may also be a consideration and so it may be desirable for a modular structure and the components of a modular structure, in the disassembled state, to be limited in size so that less space is required to transport the structure. SUMMARY According to an embodiment of a first aspect, there is provided a coupling device for a modular structure, the coupling device comprising: a base plate; a first wall extending from the base plate; a second wall extending from the base plate; a channel defined between the first wall and the second wall and configured to receive a first portion of a complementary coupling device; and a capping piece extending from the base plate. Thus, according to embodiments of the present invention, a coupling device is provided that may interact with a complementary device. The elements of the coupling device may be arranged such that they are configured to receive elements of the complementary device. The complementary device may interact with the coupling device in a way that enables the two devices to interlock and / or come together to provide a combined piece with a substantially uniform outer shape. For example, the combined piece may provide a 3D shape with at least four substantially uniform faces. The complementary coupling device may be a mirror image of the coupling device about an outer edge of the coupling device, along the length of the coupling device. The correspondence of the devices may allow for them to be connected and used as part of a modular structure that may be assembled quickly and efficiently. The base plate may be aligned with a first plane. The first wall may be aligned with a second plane that is different to the first plane. The second wall may be aligned with a third plane that is different to the first plane. The third plane may the same as or different to the second plane. The capping piece may be aligned with a fourth plane that is different to the first plane, the second plane and the third plane. The planes may define a three dimensional ‘XYZ’ plane, such that the first plane may correspond to the x plane, the second and third planes may correspond to the y plane and the fourth plane may correspond to the z plane. The base plate, the first and second walls and the capping piece may therefore be perpendicular to each other. The first wall may be perpendicular to the base plate, such that it extends from the base plate to provide an angle of 90° between the first wall and the base plate. Alternatively, the first wall may not be perpendicular to the base plate such that it extends from the base plate to provide an angle that is not equal to 90° between the first wall and the base plate. The first wall may be substantially perpendicular to the base plate, such that it extends from the base plate to provide an angle of around 90° between the first wall and the base plate. For example, the angle may be between 75° and 105°. The same possibilities apply to the second wall. The first wall and the second wall of the coupling device may be parallel to each other such that the channel formed between the first wall and the second wall is uniform and has a consistent width along the length of the walls. Alternatively, the first wall and the second wall may be angled such that they are not parallel to each other. For example, the channel formed between the first wall and the second wall may not be uniform and may be wider at one end than the other. The width of the first wall may be uniform / consistent, such that the first wall is the same width along its entire length. Alternatively, the width of the first wall may not be uniform, such that the first wall is not the same width along its entire length. The same possibilities apply to the second wall. The first portion of the complementary device may have a shape corresponding to the shape of the channel such that the first portion of the complementary device may be received in the channel. For example, the first wall and the second wall may each extend perpendicularly from the base plate and may be parallel to each other such that the channel defined between the first wall and the second wall has a cuboid shape. The first portion of the complementary device may then also have a cuboid shape such that it can slot into the channel. The first portion of the complementary device may also be referred to as a first member, first part or first element. The capping piece may be perpendicular to the base plate, such that it extends from the base plate to provide an angle of 90° between the capping piece and the base plate. Alternatively, the capping piece may not be perpendicular to the base plate such that it extends from the base plate to provide an angle that is not equal to 90° between the capping piece and the base plate. The capping piece may be substantially perpendicular to the base plate, such that it extends from the base plate to provide an angle of around 90° between the capping piece and the base plate. For example, the angle may be between 75° and 105°. The capping piece may be connected to the first wall and / or the capping piece may be connected to the second wall. Alternatively, the capping piece may not be connected to the first wall and / or the second wall, such that a gap is provided between the capping piece and the first wall and / or the second wall. The first wall, the second wall and the capping piece may extend from a face of the base plate. The face of the base plate may be flat and uniform, and may be referred to as a top face or internal face. The capping piece may be configured to engage with a secondary device which may be provided in cooperation with the coupling device, e.g. a complementary coupling device. A section of the capping piece may be configured to interact with a portion of the secondary device. For example, one or more sections of a face of the capping piece may be configured to engage with one or more portions of the complementary coupling device, such that the one or more portions of the complementary device may abut against the one or more sections of the face of the capping piece when the first portion of a complementary coupling device is received in the channel defined between the first wall and the second wall. The capping piece may also be referred to as an end section or end plate. The first wall and the capping piece may be connected such that the first wall extends from the capping piece, along the length of base plate. The first wall may be perpendicular to the capping piece, such that it extends from the capping piece to provide an angle of 90° between the first wall and the capping piece. Alternatively, the first wall may not be perpendicular to the capping piece such that it extends from the capping piece to provide an angle that is not equal to 90° between the first wall and the capping piece. The first wall may be substantially perpendicular to the capping piece, such that it extends from the capping piece to provide an angle of around 90° between the first wall and the capping piece. For example, the angle may be between 75° and 105°. The same possibilities apply to the second wall and its relation to the capping piece. The coupling device may also be referred to as a clevis or an F clevis. The profile of the coupling device may be an F shape when viewed from the end of the device opposite to the end at which the capping piece may be provided. For example, the base plate may provide the vertical branch of the F shape, and the first and second walls may provide the horizontal branches of the F shape. The coupling device may be formed from metal. The complementary coupling device may be formed from metal. For example, the coupling device and / or complementary coupling device may be formed from structural steel, aluminum, or the similar. However, any material may be used and the choice of material may application dependent. The first wall may extend from the base plate along a first outer edge of the base plate so as to align with the first outer edge of the base plate. The second wall may extend from the base plate along a middle section of the base plate between the first outer edge of the base plate and a second outer edge of the base plate so as to not align with the first outer edge of the base plate or the second outer edge of the base plate. The arrangement of the second wall may define an overhang section of the base plate between the second wall and the second outer edge of the base plate. The overhang section of the base plate may be configured to engage with a second portion of the complementary coupling device. The first wall may therefore be aligned with an outer edge of the base plate such that the base plate and the first wall provide two outer faces of the coupling device. When provided in combination with a complementary device, the elements of the complementary device corresponding to the base plate and the first wall may provide another two outer faces of the combined piece. The first wall may be arranged to be perpendicular to the base plate such that the provided two outer faces are at 90°. The second wall may extend from a middle section of the base plate which is in between the first outer edge and a second outer edge that is opposite the first outer edge. The second wall may be positioned closer to the second outer edge than the first outer edge, with the channel defined between the first and second walls. The first outer edge may be referred to as a first edge of the base plate. The second outer edge may be referred to as a second edge of the base plate. The first wall and the second wall may extend from a face of the base plate. The section of the base plate that is provided between the second wall (on the side of the second wall that does not face the first wall) and the second outer edge of the base plate may define an overhang section of the base plate. The overhang section of the base plate may also be referred to as a base plate overhang section, a base plate engagement section or a second channel. The overhang section of the base plate is arranged so as to receive a second part of the complementary device. For example, when the two devices are combined such that the first portion of the complementary coupling device is received in the channel defined between the first wall and the second wall of the coupling device, the second portion of the complementary coupling device may be received by the overhang section of the base plate, e.g. a section or face of the second portion may abut against with overhang section of the base plate. The part of the complementary device (e.g. the second portion of a complementary coupling device) that engages with the overhang section of the base plate may be equivalent to the first wall of the coupling device, i.e. the overhang section is configured to receive and engage with a portion of the complementary device that corresponds to the first wall. The second portion of the complementary coupling device may be a wall that runs parallel to the first portion of the complementary coupling device. The second portion of the complementary coupling device may also be referred to as a second member, second part or second element. The width of the overhang section of the base plate between the second wall and the second outer edge of the base plate may correspond to or be equal to the width of the first wall. Alternatively or additionally, the width of the overhang section of the base plate may correspond to or may be equal to the width of the channel defined between the first wall and the second wall. The first wall and the second wall may be the same width. The first wall, the channel, the second wall and the overhang section may all be the same width. The width of the first wall may, for example, be 25mm or may be between 20mm and 30mm. Alternatively, the width of the first wall may, for example, be 50mm or may be between 40mm and 60mm. The widths may correspond or may be substantially the same or equal. That is, the widths may not be exactly equal but may, for example, be within 10mm range of each other (e.g. ±5mm), e.g. the width of the overhang section of the base plate between the second wall and the second outer edge of the base plate may be within 10mm of the width of the first wall. This may provide a tolerance and allow the coupling device to receive the complementary coupling device more easily. It may also provide a tolerance for either or both of the devices to be painted / powder coated or for any other finishing to be applied. The base plate overhang section may be the same width as the first wall so as to engage with and receive a portion of the complementary device that is equivalent to the first wall. Therefore, the first wall equivalent portion of the complementary device may align with the second outer edge of the base plate when the device and the complementary device are combined. The width of the channel defined between the first wall and the second wall may correspond to or be equal to the width of the second wall. The width of the channel may be the same as the width of the second wall so as to engage with and receive a portion of the complementary device that is equivalent to the second wall. Therefore, the second wall equivalent portion of the complementary device may slot into the channel between the first wall and the second wall of the device when the device and the complementary device are combined. The widths may correspond or be substantially the same or equal. That is, the widths may not be exactly equal but may, for example, be within 10mm range of each other (e.g. ±5mm), e.g. the width of the channel defined between the first wall and the second wall may be within 10mm of the width of the second wall. The dimensions of the portions of the coupling device and the complementary coupling device may allow for the devices to be combined in a manner which does not provide much play or movement between the devices when they are combined. This may increase the load bearing capabilities of the combined devices, and therefore the amount of weight that a modular structure comprising the devices can support may be increased. The first wall may comprise a first aperture. The second wall may comprise a second aperture aligned with the first aperture. The first aperture and the second aperture may be configured to receive a locking pin. The first wall and / or the second wall may therefore each be provided with a through hole that passes through the walls. The apertures may pass through the first wall and / or the second wall in a direction aligned with the first plane. The apertures may be aligned so that a locking pin may pass through both the first wall and the second wall. The first part and the second part of the complementary device may also each be provided with apertures that pass through the first part and the second part. These apertures may also be aligned with each other. The apertures may be arranged such that a locking pin passes through the coupling device in a direction perpendicular to the direction of the channel defined between the first wall and the second wall. One or more of the apertures may be circular and configured to receive a locking pin with a cylindrical outer shape. The diameter of one or more of the apertures may be 31mm or may be between 25mm and 35mm. Alternatively, the diameter of one or more of the apertures may be 62mm or may be between 50mm and 70mm. The size and / or shape of the apertures may correspond or may be the same as other apertures. The locking pin may have a substantially cylindrical outer shape. The locking pin may come to a point (or rounded point) at one end to provide a bullet shape or rounded end bullet shape. The other end of the locking pin may comprise an overhang or engagement part that is configured to engage with and abut against the outer surface of the first wall so as to prevent the locking pin from passing completely through the apertures. The apertures of the first part and second part of the complementary device may be aligned with the first aperture of the first wall and the second aperture of the second wall when the device and the complementary device are in the combined position. A locking pin may then be inserted into the aligned apertures so as to hold the device and the complementary device in the combined position and to prevent the devices from coming apart. Therefore the locking pin may easily be inserted into the combined devices to hold them together without requiring the use of tools. This may enable a structure comprising the coupling device to be assembled quickly and efficiently. Similarly, the locking pin may be easily removed which may enable the structure to be disassembled quickly and efficiently. This may be beneficial, for example, for a temporary structure which may require fast and efficient assembly and disassembly. The locking pin may be considered as a fixing means. Other fixing means may be provided in addition to or alternatively to the locking pin. For example, one or more of the apertures may be configured to receive a bolt, screw, split pin, welded pin, etc. One or more of the apertures may be threaded so as to engage with a corresponding threaded portion of a locking bolt or locking screw, such that the locking bolt or locking screw may be screwed into aligned apertures to secure the devices in the combined position. This may be beneficial, for example, for a permanent or semi-permanent structure in which a more secure fixing means may be preferred since disassembly is not a consideration or is a lesser consideration. The locking pin (or other fixing means) may be formed from metal. For example, the locking pin (or other fixing means) may be formed from structural steel, aluminum, or the similar. However, any material may be used and the choice of material may application dependent. The capping piece may extend from the base plate along a third outer edge of the base plate so as to align with the third outer edge of the base plate. The capping piece may therefore extend from an end of the base plate. The third outer edge may be the edge that connects the first outer edge and the second outer edge of the base plate. The base plate (or face of the base plate) may have a rectangular shape and the third outer edge may be one of the shorter sides of the rectangular shape, and the first outer edge and the second outer edge may be the longer sides of the rectangular shape. The capping piece may therefore define an end of the coupling device, which an end of the first part and an end of the second part of the complementary device abut against when the device and the complementary device are combined. The capping piece may also be referred to as an end piece or an insertion piece. The first wall and the second wall may extend from the base plate and run the length of the base plate from the capping piece aligned with the third outer edge of the base plate and to a fourth outer edge of the base plate, which is opposite the third outer edge. The first wall may extend from the capping piece along a second outer edge of the capping piece so as to align with the second outer edge of the capping piece. A top edge of the first wall may extend from the face of the capping piece at a point of the capping piece between a first outer edge of the capping piece and a third outer edge of the capping piece that is opposite to the first outer edge of the capping piece. This arrangement may define an overhang section of the capping piece between the top edge of the first wall and the third outer edge of the capping piece. The first wall and the capping piece may therefore be arranged such that the first wall is aligned with a second outer edge of the capping piece. The second outer edge of the capping piece may be aligned with the first outer edge of the base plate. The first wall may extend along a face of the capping piece from the base plate to the point of the capping piece between the first outer edge of the capping piece and the third outer edge of the capping piece that is opposite to the first outer edge of the capping piece. The top edge of the first wall is the distal edge of the first wall relative to the base plate. The tope edge may be closer to the third outer edge of the capping piece than the first outer edge of the capping piece. That is, the amount that the first wall extends from the base plate may be less than the amount that the capping piece extends from the base plate, with the difference being the overhang section of the capping piece. The overhang section of the capping piece may also be referred to as a capping piece overhang section. The second outer edge of the capping piece may be the edge that connects the first outer edge and the third outer edge of the capping piece. The first outer edge of the capping piece may be aligned with the base plate, i.e. the first outer edge of the capping piece may be connected to the third outer edge of the base plate. The second wall may be provided in the same way as the first wall with respect to the capping piece, such that the overhang section of the capping piece is also defined between a top edge of the second wall and the third outer edge of the capping piece. The width of the overhang section of the capping piece between the top edge of the first wall and the third outer edge of the capping piece may correspond to or be equal to the depth of the base plate. That is, the distance from the top edge of the first wall (and / or the top edge of the second wall) to the third outer edge of the capping piece may correspond to or be equal to the thickness of the base plate. The depth of the capping piece overhang section may be the same as the thickness of the base plate so as to engage with and receive a portion of the complementary device that is equivalent to the base plate. Therefore, the base plate equivalent portion of the complementary device may align with the third outer edge of the capping piece when the device and the complementary device are combined. In other words, the overhang section of the capping piece may be arranged so as to receive / engage with a third part of the complementary device when the two devices are combined. The part of the complementary device that engages with the overhang section of the capping piece may be equivalent to the base plate of the coupling device, i.e. the overhang section may be configured to receive and engage with a portion of the complementary device that corresponds to the base plate. This may therefore contribute to a substantially uniform outer shape of the devices when they are combined. The depth of the base plate may, for example, be 20mm or may be between 15mm and 25mm. Alternatively, the depth of the base plate may, for example, be 40mm or may be between 30mm and 50mm. The widths / depths may correspond or may be substantially the same or equal. That is, the widths may not be exactly equal but may, for example, be within 10mm range of each other (e.g. ±5mm), e.g. the width of the overhang section of the capping piece between the top edge of the first wall and the third outer edge of the capping piece may be within 10mm of the depth of the base plate. The capping piece may comprise an engagement section that extends from the capping piece in a direction opposite to the extension of the base plate from the capping piece. The engagement section may be configured to engage with a connecting member. That is, the engagement section may extend from the face of the capping piece which is different to the face of the capping piece from which the first wall and / or second wall may extend. The engagement section may increase the thickness of the capping piece so that the capping piece may engage with another component, such as a connecting member. The engagement section may have a smaller external profile than the capping piece or it may be the same or bigger. The connecting member may be a strut or length of box section. The connecting member may also be referred to as a lateral connecting member or a connecting piece. The engagement section may be configured for insertion into the end of the connecting member, i.e. the engagement section may be received into a hollow end of the box section. For example, the connecting member may be a 100mm x 100mm square hollow section (SHS) and the engagement section may be configured to be received in the SHS. The thickness of the walls of the SHS may vary and may, for example, be application specific. In some applications, the walls of the SHS may be 6mm to 12mm, inclusive. In other applications (for example, larger applications or applications that are require to support a heavier load) the thickness of the walls of the SHS may be greater than 12mm. The engagement section may comprise one or more recesses provided along the length of one or more faces of the engagement section. The one or more recesses may be configured to receive a seam of the connecting member. The thickness of the walls of the connecting member may be the same thickness as the base plate, such that the outer edge of the connecting member may be aligned with the outer face of the base plate when the engagement section is received into the end of the connecting member. The connecting member may be formed from metal. For example, the connecting member may be formed from structural steel, aluminum, or the similar. However, any material may be used and the choice of material may application dependent. The engagement section may comprise an engagement aperture configured to receive a locking pin. The engagement aperture may pass through the engagement section. The engagement section may therefore comprise a through hole which passes through the engagement section. The engagement aperture may be provided through the engagement section from a face of the engagement section that is aligned with the base plate, to an opposite face of the engagement section. These faces may be different to the one or more faces on which one or more channels are provided in the engagement section. The engagement aperture may be provided in line with the second plane and / or third plane. That is, the engagement aperture may pass through the engagement section in a direction aligned with the second and / or third plane. The engagement aperture may be configured to receive a locking pin such that the locking pin passes through the width of the engagement section when inserted into the engagement aperture. The engagement aperture may be arranged such that a locking pin passes through the engagement section in a direction perpendicular to the direction of a locking pin that passes through the apertures of the first wall and the second wall. The connecting member may also be provided with apertures that pass through two opposing faces of the connecting member. For example, an aperture may be provided in each of two opposing sides of a length of box section such that they align with each other. The connecting member may be a 100mm x 100mm square hollow section (SHS). The aperture of the connecting member may be aligned with the engagement aperture when the engagement section is received into the end of the connecting member. A locking pin may then be inserted into the aligned apertures so as to hold the device and the connecting member in the connected position and to prevent the device and the connecting member from coming apart. Therefore the locking pin may easily be inserted into the connected components to hold them together without requiring the use of tools. This may enable a structure comprising the coupling device to be assembled quickly and efficiently. Similarly, the locking pin may be easily removed which may enable the structure to be disassembled quickly and efficiently. This may be beneficial, for example, for a temporary structure, which may require fast and efficient assembly and disassembly. One or more of the apertures may be circular and configured to receive a locking pin with a cylindrical outer shape. The diameter of one or more of the apertures may be 31mm or may be between 25mm and 35mm. Alternatively, the diameter of one or more of the apertures may be 62mm or may be between 50mm and 70mm. The size and / or shape of the apertures may correspond or may be the same as other apertures. The locking pin may have a substantially cylindrical outer shape. The locking pin may come to a point (or rounded point) at one end to provide a bullet shape or rounded end bullet shape. The other end of the locking pin may comprise an overhang or engagement part that is configured to engage with and abut against the outer surface of the engagement section and / or the connecting member so as to prevent the locking pin from passing completely through the apertures. The locking pin may be considered as a fixing means. Other fixing means may be provided in addition to or alternatively to the locking pin. For example, one or more of the apertures may be configured to receive a locking bolt or locking screw. One or more of the apertures may be threaded so as to engage with a corresponding threaded portion of a locking bolt or locking screw, such that the locking bolt or locking screw may be screwed into aligned apertures to secure the coupling device and the connecting member. This may be beneficial, for example, for a permanent or semi-permanent structure in which a more secure fixing means may be preferred since disassembly is not a consideration or is a lesser consideration. The locking pin (or other fixing means) may be formed from metal. For example, the locking pin (or other fixing means) may be formed from structural steel, aluminum, or the similar. However, any material may be used and the choice of material may application dependent. The size of the apertures of the engagement section and / or the connecting member, and the first wall and / or second wall may be the same. The same locking pins may be compatible with the apertures of the engagement section and / or the connecting member, and the first wall and / or second wall. This may reduce the need for different types of components and improve the flexibility and efficiency, and / or reduce the complexity of assembling a structure using the various components. According to an embodiment of a first aspect, there is provided a coupling arrangement for a modular structure, the coupling arrangement comprising: a first coupling device comprising: a first device base plate; a first device first wall extending from the first device base plate; a first device second wall extending from the first device base plate; a first device channel defined between the first device first wall and the first device second wall; and a first device capping piece extending from the first device base plate; and a second coupling device comprising: a second device base plate; a second device first wall extending from the second device base plate; a second device second wall extending from the second device base plate; a second device channel defined between the second device first wall and the second device second wall; and a second device capping piece extending from the second device base plate, wherein the first coupling device and the second coupling device are configured to engage so as to form a unitary piece when in a coupled positon; and the first device channel is configured to receive the second device second wall and the second device channel is configured to receive the first device second wall when in the coupled position. A coupling arrangement may therefore be provided which comprises a first coupling device and a second coupling device. The first coupling device and the second coupling device may be slotted together such that the second wall of the second device is inserted into the channel of the first device and the second wall of the first device is inserted into the channel of the second device. When in the coupled position, the two devices provide a unitary piece. That is, the external profile of the coupling arrangement when in the coupled position may be substantially uniform on at least four faces of the 3D shape. The base plate and the first wall of the first device may provide two of the faces and the base plate and the first wall of the second device may provide the other two faces. Thus, when in the coupled position, the first wall of the first device may be arranged opposite to the first wall of the second device and the base plate of the first device may be arranged opposite to the base plate of the second device. The second wall of the first device and the second wall of the second device may be provided between the first wall of the first device and the first wall of the second device. The unitary piece may also be referred to as a solid piece or a block piece. The first coupling device may correspond to the coupling device discussed above and the second coupling device may correspond to the complementary coupling device discussed above, or vice versa. Any of the above described aspects may be applicable to the first coupling device and / or the second coupling device. The above referenced combined position may be equivalent to the coupled position. The first coupling device may be formed from metal. The second coupling device may be formed from metal. For example, the first coupling device and / or the second coupling device may be formed from structural steel, aluminum, or the similar. However, any material may be used and the choice of material may application dependent. The external profile / cross-section of the first coupling device and the second coupling device when in the coupled position may have a substantially rectangular prism shape. The first wall of the first device may be provided perpendicular to the base plate of the first device, and the first wall of the second device may be provided perpendicular to the base plate of the second device. When in the coupled position, the first wall of the second device may be provided perpendicular to the base plate of the first device, and the first wall of the first device may be provided perpendicular to the base plate of the second device. The coupling arrangement in the coupled position may therefore have a substantially rectangular crosssection when viewed from an end, i.e. when viewed from the capping piece of the first device or the capping piece of the second device. The coupling arrangement in the coupled position may have a substantially rectangular or square tube shape profile / cross-section, with the first walls of the devices and the base plates of the devices providing the outer surfaces of the substantially rectangular or square tube shape. One or more edges of the portions of the first device and / or second device may be rounded or bevelled such that one or more of the corners of the substantially rectangular or square tube shape are rounded or bevelled. The capping piece of the first device and the capping piece of the second device may be arranged opposite to each other when in the coupled position. For example, the faces of each capping piece from which the respective first and second walls extend may be provided opposite to each other when in the coupled position. The capping pieces of the devices may be perpendicular to the walls and base plates of the devices. The capping piece of the first device and / or the capping piece of the second device may protrude from, may be aligned with, or may be set back from (smaller than) the substantially rectangular prism external profile / cross-section. In other words, the capping piece for each device may or may not be aligned with the respective base plate and / or first wall. The first device first wall may comprise a first device first aperture. The first device second wall may comprise a first device second aperture aligned with the first device first aperture. The second device first wall may comprise a second device first aperture. The second device second wall may comprise a second device second aperture aligned with the second device first aperture. The first device first aperture, the first device second aperture, the second device first aperture and the second device second aperture may be aligned when in the coupled position and may be configured to receive a locking pin. The first wall and / or the second wall of the first device may therefore each be provided with a through hole that passes through the walls. The apertures may pass through the first wall and / or the second wall in a direction aligned with the first plane, i.e. in a direction perpendicular to the length of the first wall and / or second wall. The apertures of the first device may be aligned so that the locking pin may pass through both the first wall and the second wall of the first device. The first wall and the second wall of the second device may also each be provided with similarly configured apertures that pass through the first wall and the second wall. These apertures may also be aligned with each other. One or more of the apertures may be circular and configured to receive a locking pin with a cylindrical outer shape. The diameter of one or more of the apertures may be 31mm or may be between 25mm and 35mm. Alternatively, the diameter of one or more of the apertures may be 62mm or may be between 50mm and 70mm. The size and / or shape of the apertures may correspond or may be the same as other apertures. The locking pin may have a substantially cylindrical outer shape. The locking pin may come to a point (or rounded point) at one end to provide a bullet shape or rounded end bullet shape. The other end of the locking pin may comprise an overhang or engagement part that is configured to engage with and abut against the outer surface of the first wall so as to prevent the locking pin from passing completely through the apertures. The apertures of the first wall and second wall of the first device may be aligned with the apertures of the first wall and second wall of the second device when the devices are in the coupled position. A locking pin may then be inserted into the aligned apertures so as to hold the devices in the coupled position and to prevent the devices from coming apart or separating, e.g. moving to an uncoupled position. Therefore the locking pin may easily be inserted into the combined devices to hold them together without requiring the use of tools. This may enable a structure comprising the coupling arrangement to be assembled quickly and efficiently. Similarly, the locking pin may be easily removed which may enable the structure to be disassembled quickly and efficiently. This may be beneficial, for example, for a temporary structure, in which fast and efficient assembly and disassembly may be desirable. The locking pin may be considered as a fixing means. Other fixing means may be provided in addition to or alternatively to the locking pin. For example, one or more of the apertures may be configured to receive a locking bolt or locking screw. One or more of the apertures may be threaded so as to engage with a corresponding threaded portion of a locking bolt or locking screw, such that the locking bolt or locking screw may be screwed into aligned apertures to secure the devices in the coupled position. This may be beneficial, for example, for a permanent or semi-permanent structure in which a more secure fixing means may be preferred since disassembly is not a consideration or is a lesser consideration. The locking pin (or other fixing means) may be formed from metal. For example, the locking pin (or other fixing means) may be formed from structural steel, aluminum, or the similar. However, any material may be used and the choice of material may application dependent. The second coupling device may be a mirror of the first coupling device about a first outer edge of the first device base plate, along the length of the first device first wall. The configuration of the first coupling device may therefore correspond to the configuration of the second coupling device. The second device may be a mirror image of the first device about the outer edge of the first device on the first wall side. The arrangement of the first device base plate may be the same as the arrangement of the second device base plate, and the arrangement of the first device capping piece may be the same as the arrangement of the second device capping piece. The arrangement of the first device first wall and the second device second wall may be different such that the first device first wall extends from a side of the first device base plate that is opposite to the side of the second device base plate from which the second device first wall extends from. The first device second wall and the first device channel may therefore be provided on the opposite side of the first device first wall compared with the second device second wall and second device channel with respect to the second device first wall. This configuration of the first device and the second device may enable the devices to slot together into the coupled position and provide a substantially uniform outer shape. For example, the capping pieces of the devices may correspond such that they provide the ends of the coupling arrangement in the coupled position. The base plate and first wall of each device may provide the other four sides of the three-dimensional shape of the coupling arrangement in the coupled position. The correspondence of the devices may allow for them to be connected and used as part of a modular structure that may be assembled quickly and efficiently. The first coupling device may be the coupling device of any of the previously discussed aspects. The second coupling device may be the complementary coupling device of any of the previously discussed aspects. Alternatively, the first coupling device may be the coupling device of any of the previously discussed aspects and the second coupling device may be the complementary coupling device of any of the previously discussed aspects. Any of the aspects discussed in relation to the coupling device may be applicable to the first coupling device and / or the second coupling device. Any of the aspects discussed in relation to the complementary coupling device may be applicable to the first coupling device and / or the second coupling device. The first portion of the complementary coupling device may be the second device second wall. The second portion of the complementary coupling device may be the second device first wall. In other words, the first portion of the complementary device may be the second wall of the second coupling device, such that the channel of the first device may be configured to receive the second device second wall, in the same way that the channel of the above described coupling device may be configured to receive the first portion of the complementary device. Similarly, the second portion of the complementary device may be the first wall of the second coupling device, such that the overhang section of the first device base plate may be configured to receive and engage with the second device first wall, in the same way that the base plate overhang section of the above described coupling device may be configured to engage with the second portion of the complementary device. The above may still be applicable if the first coupling device and the second coupling device are reversed. According to an embodiment of a third aspect, there is provided a coupling system for a modular structure, the coupling system comprising: a first coupling device comprising: a first device base plate; a first device first wall extending from the first device base plate; a first device second wall extending from the first device base plate; a first device channel defined between the first device first wall and the first device second wall; and a first device capping piece extending from the first device base plate; a second coupling device comprising: a second device base plate; a second device first wall extending from the second device base plate; a second device second wall extending from the second device base plate; a second device channel defined between the second device first wall and the second device second wall; and a second device capping piece extending from the second device base plate; a bridging piece comprising: a top plate; a bridging first wall extending from the top plate; a bridging second wall extending from the top plate; and a bridging channel defined between the bridging first wall and the bridging second wall, wherein the bridging first wall is configured to receive the first device capping piece of the first coupling device when in a coupled position; and the bridging second wall is configured to receive the second device capping piece of the second coupling device when in the coupled position. A coupling system may therefore be provided which comprises two coupling devices and a bridging piece arranged between the two coupling device to connect the devices when the system is in the coupled position. The first coupling device may correspond to the coupling device and / or the first coupling device of the coupling arrangement discussed above and the second coupling device may correspond to the complementary coupling device and / or the second coupling device of the coupling arrangement discussed above, or vice versa. Any of the above described aspects may be applicable to the first coupling device and / or the second coupling device. The bridging first wall may comprise a first connection aperture (or first connection opening) into which the capping piece of the first device may be inserted to couple the first device and the bridging piece. The bridging second wall may comprise a second connection aperture (or second connection opening) into which the capping piece of the second device may be inserted to couple the second device and the bridging piece. The first connection aperture may therefore have a shape corresponding to the outer profile of the first device capping piece. The second connection aperture may have a shape corresponding to the outer profile of the second device capping piece. The first coupling device and / or the second coupling device may therefore be connected to the bridging piece by way of insertion to hold them together without requiring the use of tools. This may enable a structure comprising the coupling system to be assembled quickly and efficiently. Similarly, the first coupling device and / or the second coupling device may be easily removed from the connection apertures to disconnect the components which may enable the structure to be disassembled quickly and efficiently. This may be beneficial for a temporary structure, which may require fast and efficient assembly and disassembly. The components of the coupling system may therefore correspond and engage in a way which may enable a modular structure to be constructed using the components in a repetitive, sequential manner. The first coupling device may be formed from metal. The second coupling device may be formed from metal. The bridging piece may be formed from metal. For example, the first coupling device and / or the second coupling device and / or the bridging piece may be formed from structural steel, aluminum, or the similar. However, any material may be used and may application dependent. The second coupling device may be a mirror of the first coupling device about a first outer edge of the first device base plate, along the length of the first device first wall. The configuration of the first coupling device may therefore correspond to the configuration of the second coupling device. The second device may be a mirror image of the first device about the outer edge of the first device on the first wall side. The arrangement of the first device base plate may be the same as the arrangement of the second device base plate, and the arrangement of the first device capping piece may be the same as the arrangement of the second device capping piece. The arrangement of the first device first wall and the second device second wall may be different such that the first device first wall extends from a side of the first device base plate that is opposite to the side of the second device base plate from which the second device first wall extends from. The first device second wall and the first device channel may therefore be provided on the opposite side of the first device first wall compared with the second device second wall and second device channel with respect to the second device first wall. The first coupling device may be configured to engage with a third coupling device corresponding to the second coupling device. The first coupling device and the third coupling device may correspond to the first coupling device and the second coupling device of the coupling arrangement discussed above. The second coupling device may be configured to engage with a fourth coupling device corresponding to the first coupling device. The second coupling device and the fourth coupling device may correspond to the second coupling device and the first coupling device of the coupling arrangement discussed above. The coupling system may therefore comprise multiple coupling devices and / or multiple coupling arrangements. The configuration of the first coupling device and the second coupling device may enable the devices to interact with and connect to corresponding coupling devices which may enable a modular and repeated structure to be assembled. The structure may be scaled by providing a series of coupling systems connected, for example, by connecting members that are configured to engage with capping pieces of the coupling devices. The first device base plate may be proximate to the distal end of the bridging first wall when in the coupled position. The second device base plate may be proximate to the proximal end of the bridging second wall when in the coupled position. In other words, the first device base plate may be arranged closer to the end of the bridging first wall that is furthest from the top plate when in the coupled position. The second device base plate may be arranged closer to the end of the bridging second wall that is closest to the top plate when in the coupled position. The top plate may be provided on the same plane as the first device first wall and / or the second device first wall when in the coupled position. The top plate of the bridging piece may comprise a top aperture arranged between the bridging first wall and the bridging second wall. The top aperture may be configured to receive an upper connecting piece. The upper connecting piece may be configured to engage with a support piece. The support piece may be configured to support a covering of the modular structure, such as, for example, a roof covering provided over the structure. For example, the support piece may act as a receiver for a roof profile upon which sheeting may be received to act as a covering or roof for the modular structure. The top aperture may be circular and may, for example, have a diameter of 42mm or may have, for example, a diameter between 32mm and 52mm. Alternatively, the top aperture may have a diameter of 84mm or, for example, a diameter between 74mm and 94mm The upper connecting piece may be formed from metal. The support piece may be formed from metal. The bridging first wall may comprise a first bridging aperture. The bridging second wall may comprise a second bridging aperture aligned with the first bridging aperture. The first bridging aperture and the second bridging aperture may be configured to receive a locking pin. The bridging first wall and / or the bridging second wall of the first device may therefore each be provided with a through hole that passes through the walls. The apertures may pass through the bridging first wall and / or the bridging second wall in a direction aligned with the walls of first and second devices. The apertures of the bridging piece may be aligned so that the locking pin may pass through both the bridging first wall and the bridging second wall of the bridging piece. The bridging first wall and the bridging second wall may also each be provided with further apertures that are aligned and are configured to receive another locking pin. One set of aligned bridging apertures may be provided at one end of the bridging walls and another set of aligned bridging apertures may be provided at the other end of the bridging walls. The first coupling device and / or the second coupling device may be provided between the sets of aligned bridging apertures when in the coupled position. That is, the opening of the bridging first wall which is configured to receive the capping piece of the first coupling device may be provided between a first bridging aperture of the bridging first wall and another bridging aperture of the bridging first wall. The opening of the bridging second wall, which is configured to receive the capping piece of the second coupling device, may be provided between a second bridging aperture of the bridging second wall and another bridging aperture of the bridging second wall. One or more of the bridging apertures may be circular and configured to receive a locking pin with a cylindrical outer shape. The diameter of one or more of the bridging apertures may be 31mm or may be between 25mm and 35mm. Alternatively, the diameter of one or more of the apertures may be 62mm or may be between 50mm and 70mm. The size and / or shape of the apertures may correspond or may be the same as other apertures. The locking pin may have a substantially cylindrical outer shape. The locking pin may come to a point (or rounded point) at one end to provide a bullet shape or rounded end bullet shape. The other end of the locking pin may comprise an overhang or engagement part that is configured to engage with and abut against the outer surface of the bridging first wall or the bridging second so as to prevent the locking pin from passing completely through the apertures. The coupling system may further comprise a connecting member. This connecting member may be the same as the connecting member discussed above. The connecting member may also be provided with apertures that pass through two opposing faces of the connecting member. For example, an aperture may be provided in each of two opposing sides of a length of box section such that they align with each other. The bridging channel may be configured to receive a connecting member. The width of the connecting member may be the same as or may correspond with the width of the bridging channel. The apertures of the connecting member may be aligned with the bridging apertures when the connecting member is positioned in the bridging channel. A locking pin may then be inserted into the aligned apertures so as to hold the bridging piece and the connecting member in the connected position and to prevent the bridging piece and the connecting member from coming apart. Therefore the locking pin may easily be inserted into the connected components to hold them together without requiring the use of tools. This may enable the coupling system to be assembled quickly and efficiently. Similarly, the locking pin may be easily removed which may enable the system to be disassembled quickly and efficiently. This may be beneficial, for example, for a temporary structure, which may require fast and efficient assembly and disassembly. The locking pin may be considered as a fixing means. Other fixing means may be provided in addition to or alternatively to the locking pin. For example, one or more of the apertures may be configured to receive a locking bolt or locking screw. One or more of the apertures may be threaded so as to engage with a corresponding threaded portion of a locking bolt or locking screw, such that the locking bolt or locking screw may be screwed into aligned apertures to secure the bridging piece and the connecting member in the connected position. This may be beneficial, for example, for a permanent or semi-permanent structure in which a more secure fixing means may be preferred since disassembly is not a consideration or is a lesser consideration. The locking pin (or other fixing means) may be formed from metal. The bridging channel may be configured to receive a coupling arrangement according to any of the above aspects. The coupling arrangement may be in the coupled position when positioned in the bridging channel. The system may therefore comprise a coupling arrangement such as that discussed above. Any of the above aspects may be applied to the coupling arrangement of the coupling system. The bridging channel may therefore be configured to receive the coupling arrangement, with both the arrangement and the system in the coupled positions. The width of the bridging channel may be the same as or may correspond with the width of the coupling arrangement. The coupling arrangement may be provided in the bridging channel in a direction perpendicular to the direction of the base plates of the first and second coupling devices. That is, the devices of the coupling arrangement may be provided perpendicular to the first coupling device and the second coupling device when in the coupled position. The first device and / or the second device of the coupling arrangement may be provided with a connecting member, such as the connecting member discussed above. The capping piece of the first device and / or the capping piece of the second device of the coupling arrangement may comprise an engagement section, such as the engagement section (extended capping piece) discussed above. For example, the capping piece of the first device of the coupling device may comprise an engagement section that may be inserted into an end of a box section connecting member. The connecting member may be formed from metal. The connecting member may be a 100mm x 100mm square hollow section (SHS). A locking pin may be inserted through apertures in the bridging walls, apertures in the connecting member and an aperture in the engagement section. These apertures may align when in the coupled position and a locking pin may be inserted through the aligned apertures to maintain the components in the coupled position. The locking pin may be considered as a fixing means. Other fixing means may be provided in addition to or alternatively to the locking pin. For example, one or more of the apertures may be configured to receive a locking bolt or locking screw. One or more of the apertures may be threaded so as to engage with a corresponding threaded portion of a locking bolt or locking screw, such that the locking bolt or locking screw may be screwed into aligned apertures to secure the components in the coupled position. The same may apply to the second device of the coupling arrangement such that the coupling system comprises multiple connecting members. For example, a connecting member may be provided at either end of the bridging channel. The engagement section of the first coupling device of the coupling arrangement may be connected to a first connecting member at one end of the bridging channel and the engagement section of the second coupling device of the coupling arrangement may be connected to a second connecting member at the other end of the bridging channel. The connecting members may be formed from metal. The opposite end of one or more of the connecting members may be connected to a corresponding coupling system such that the structure may be assembled in a repeated and modular fashion. For example, the other end of one of the connecting members may be connected to an engagement section of a coupling device, provided as part of a coupling arrangement, the coupling arrangement provided in the bridging channel of a corresponding coupling system. The coupling system may therefore allow for a modular structure to be provided that may be scaled to a desired size, assembled easily and efficiently, disassembled easily and efficiently, comprised of a set number of different types of components, and / or disassembled to a reduced size for easier and more efficient transportation / storage. The first coupling device may be the coupling device of any of the previously discussed aspects. The second coupling device may be the coupling device of any of the previously discussed aspects. Any of the aspects discussed in relation to the coupling device above may be applicable to the first coupling device and / or the second coupling device. Any of the aspects discussed in relation to the complementary coupling device above may be applicable to the first coupling device and / or the second coupling device. According to an embodiment of a fourth aspect, there is provided a modular structure comprising a coupling device according to aspects of the present disclosure, and / or a coupling arrangement according to aspects of the present disclosure, and / or a coupling system according to aspects of the present disclosure, and / or any combination thereof. The structure may be a permanent, semi-permanent or temporary structure. The structure may be a roof structure. The structure may be a roof of a staging structure. The system may be referred to as a clock work staging system. Features and sub-features of the apparatus aspects may be applied in any combination to the method aspects and vice versa. An apparatus according to preferred embodiments may comprise any combination of the method aspects. The apparatus according to preferred embodiments is described as configured or arranged to or simply ‘to’ carry out certain functions. The invention is described in terms of particular embodiments. Other embodiments are within the scope of the following claims. For example, the elements of the invention may be provided in a different arrangement and still achieve desirable results. BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments will now be described, by way of example only, with reference to the following drawings, in which: Figs. 1A to ID show variants of a coupling device according to embodiments of aspects of the invention; Figs. 2A to 2C show variants of a coupling device according to embodiments of aspects of the invention; Figs. 3A to 3G show variants of a coupling arrangement according to embodiments of aspects of the invention; Figs. 4A and 4B show variants of a coupling system according to embodiments of aspects of the invention; Figs. 5A to 5G show a coupling system according to an embodiment of an aspect of the invention; Fig. 6 shows a modular structure according to an embodiment of an aspect of the invention; and Fig. 7 shows a modular structure according to an embodiment of an aspect of the invention. DETAILED DESCRIPTION Embodiments of the present disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting examples that are described and / or illustrated in the drawings and detailed in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as the person skilled in the art would recognise, even if not explicitly stated herein. Descriptions of well-known components may be omitted so as to not unnecessarily obscure the embodiments of the present disclosure. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments of the present disclosure may be practiced and to further enable those of skill in the art to practice the same. Accordingly, the examples herein should not be construed as limiting the scope of the embodiments of the present disclosure. The scope is defined by the appended claims. It is understood that the embodiments of the present disclosure are not limited to the particular methodology, devices, apparatus, materials, applications, etc., described herein, as these may vary. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to be limiting in scope of the embodiments as claimed. It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. The words “comprises / comprising” and the words “having / including” when used herein with reference to embodiments of aspects are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the embodiments of the present disclosure belong. Preferred methods, devices, and processes are described, although any methods, devices and processes similar or equivalent to those described herein may be used in the practice or testing of the embodiments. As discussed above, it is desirable for modular structures to be able to be assembled and disassembled quickly and efficiently. It is also desirable for the disassembled structures to be small in size so that less space is required to transport the structure between locations. Embodiments of the present invention provide a coupling device, a coupling arrangement and a coupling system. The coupling device, coupling arrangement and / or coupling system may be used in a modular structure, such as, for example, a staging structure. A structure comprising the coupling device / coupling arrangement / coupling system may be referred to as a modular structure coupling system. Embodiments of aspects may provide a modular structure to be used, for example, as a staging structure in large capacity live events. The staging structure may be a permanent, semi-permanent or temporary structure. For example, a music artist may go on a tour which includes multiple venues and locations. In some cases, these shows may be on consecutive nights, with the staging constructed and dismantled for each show. In such a case, the performer’s production crew may only have limited access to the venue prior to the show and so it is desirable for the staging structure to be assembled in a short amount of time. Similarly, the crew may not have much time after the show to disassemble the staging structure. The structure may then also need to be transported between shows, often by lorry. It is therefore desirable for modular structures to be able to be assembled and / or disassembled quickly and efficiently. It is also desirable for the disassembled structures to be small in size so that less space is required to transport the structure between locations. Embodiments of aspects may comprise a bespoke modular, flat-pack, staging structure. A staging structure comprising the coupling device, coupling arrangement and / or coupling system according to embodiments of aspects may have a high load capacity which may be provided by the arrangements of the components and the interaction between different components. For example, such a staging structure may have a load capacity of up to 120 tonnes. The coupling device, coupling arrangement and / or coupling system according to embodiments of aspects may provide a connection system which uses fabricated components that may allow for faster and safer assembly and / or disassembly, and may allow for significant reductions in carbon footprint, due to a reduced size of the modular structure when disassembled, which therefore requires less transportation to move and results in reduced carbon emissions. The three main constraints / expenses with modular structures may be characterised by the three T’s: Trucks, Time and Tension. That is, the number of trucks it takes to move a structure while disassembled from one location to another, e.g. from the location the structure is produced or stored to where it is to be assembled. Reducing the number of trucks required to transport the structure may reduce the costs and / or reduce the environmental impact, i.e. the carbon footprint. This may therefore reduce costs and reduce environmental impact. The time that it takes to erect a modular structure and the amount of load (Tension) that the structure can support when it is fully assembled provide further key aspects. In the context of staging systems, reduced assembly and disassembly time may result in a reduced interval between performances. This may also lead to reduced labour costs per build and the volume of staging system steel being transported between venues may also be reduced. In addition to the applications for modular structures discussed above, embodiments of aspects may be applied to other applications. That is, embodiments of aspects may be suitable for / may provide a variety of different structural uses. Permanent built structures may comprise embodiments of aspects. For example, a coupling device, coupling arrangement and / or coupling system may be used to provide a permanent structure. In such a permanent structure, the components may be coupled / joined together using a permanent fixing means (e.g. bolt). This is in contrast to a temporary structure in which a less permanent fixing means (e.g. a locking pin) is used which may allow for ease of disassembly. Other applications may include, but are not limited, infrastructural engineering products (such as, for example, bridges, walkways, etc.), emergency scenarios in which structures are required and where speed of assembly may be key (such as, for example, refugee accommodation, warzone hospitals, etc.) and / or in military applications (such as, for example, temporary or semi-permanent structures required in combat zones). The coupling device according to embodiments of aspects may be designed to couple / join lengths of steel, primarily in a straight line, and secondarily in a perpendicular line, allowing for the building of a structural grid. The grid may be modular and repeating. In existing structural designs an extra component is required to make this connection. For example, in a scaffolding system, the “standard” is the main vertical member and it is required at every join / node. The resulting effect of the extra joining components is the necessity for a large number of heavy steel components. For example, up to 150 in a standard configuration. The greater the number of components, the more steel there is and the more transportation (e.g. trucks) required. Embodiments of aspects may allow for the connection of pieces in a modular structure that does not require a joining piece, which may reduce the total number of components, the overall weight of the structure and / or the space required to transport the structure. Embodiments of aspects may allow for the modular structure to be assembled and disassembled in a time efficient manner due to the reduced number and variety of components. For example, embodiments of aspects may allow for a modular structure to be constructed which has less than twenty varieties of components, whereas existing system can have more than two hundred varieties. Embodiments of aspects may allow for a simplified connecting system which comprises simplified, standardised components and connectivity such that the build time may be greatly reduced. Fig. 1A is a coupling device according to an embodiment of an aspect of the invention. The coupling device comprises a base plate 11, a first wall 12, a second wall 13 and a capping piece 14a. The first wall 12 and the second wall 13 extend from the base plate 11 and are perpendicular to the face of the base plate 11. The capping piece 14a extends from the face of the base plate 11 and is provided perpendicular to the base plate 11. The capping piece 14a is also perpendicular to the first wall 12 and the second wall 13. The first wall 12 and the second wall 13 are connected to the capping piece 14a. When viewed from the end opposite to the capping piece 14a, the coupling device has an F shape profile. The first wall 12 is provided with a first aperture 15 and the second wall 13 is provided with a second aperture 16. The first aperture 15 and the second aperture 16 are aligned and may be configured to receive a pin. A channel is defined between the first wall 12 and the second wall 13. The first wall 12 may be provided on an outer edge of the base plate 11, and the second wall 13 may be provided at a distance in from an opposing edge of the base plate 11. The capping piece 14a comprises a notch 141 on at least one outer edge. The notch 141 may be configured to engage with a protrusion of a corresponding device, for example, a bridging piece. The notch 141 may ensure correct assembly with the corresponding device, for example, that the orientation of the corresponding device with respect to the coupling device is correct. As shown in Fig. 1 A, the capping piece 14a may have a thickness that is less than the widths and thicknesses of the other elements. The edges of the elements of the coupling device may be bevelled or rounded, as shown in Fig. 1 A. Fig. IB is a coupling device according to an embodiment of an aspect of the invention. The capping piece 14b of the coupling device of Fig. IB has a different configuration to the capping piece 14a of Fig. 1 A. For example, capping piece 14b is thicker than capping piece 14a. The thickness of the capping piece may be varied and adjusted in accordance with the component which the capping piece is to engage with and / or a component the coupling device is to engage with. The outer profile of capping piece 14b is larger than the outer profile of capping piece 14a. Again, the size of the capping piece may be varied and adjusted in accordance with the component which the capping piece is to engage with and / or a component the coupling device is to engage with. The coupling device of Fig. IB shows an overhang section 17 of the capping piece 14b and an overhang section 18 of the base plate 11. The width of the overhang section 17 may be the same as the depth of the base plate 11. The overhang section 18 may be the same width as the first wall 12 and / or the same width as the channel defined between the first wall 12 and the second wall 13. Fig. IC is a coupling device according to an embodiment of an aspect of the invention. The capping piece 14c of the coupling device of Fig. IC has a different configuration to the capping piece 14a of Fig. 1A and the capping piece 14b of the coupling device of Fig. IB. Capping piece 14c comprises an engagement section which extends from the capping piece 14c in a direction opposite to the direction from which the first wall 12 and the second wall 13 extend from the capping piece 14c. The capping piece 14c comprising the engagement section may be considered as an extended capping piece 14c. The capping piece 14c may be extended to provide an engagement section in order to engage with another component, such as, for example, a connecting member. The provision of the engagement section in the capping piece 14c or the size of the engagement section may vary depending on the configuration of the component with which the capping piece 14c is to engage. For example, the engagement section may be configured for insertion into a hollow end of a connecting member. Fig. ID is a coupling device according to an embodiment of an aspect of the invention. The capping piece 14d of the coupling device of Fig. ID has a different configuration to the capping piece 14a of Fig. 1A, the capping piece 14b of the coupling device of Fig. IB and the capping piece 14c of the coupling device of Fig. IC. Capping piece 14d comprises an engagement section which extends from the capping piece 14d in a direction opposite to the direction from which the first wall 12 and the second wall 13 extend from the capping piece 14d. The capping piece 14d comprising the engagement section may be considered as an extended capping piece 14d. The engagement section of capping piece 14d differs from that capping piece 14c in that the engagement section comprises an aperture 142. The aperture 142 may be configured to receive a pin (e.g. a locking pin or other fixing means, such as a locking bolt or a locking screw). Furthermore, the edges of the engagement section of capping piece 14d are rounded. This may be to better engage with a corresponding component. The capping piece 14d also comprises a first recess 143a and a second recess 143b. Each of the recesses may be configured to receive a seam of the connecting member. As can be seen from Figs. 1A to ID, the configuration of the capping piece may vary. The capping piece may be varied or adjusted to account for the component with which the capping piece is to engage and / or a component with which the coupling device is to engage. The capping piece may be varied or adjusted to ensure that its shape corresponds to the shape of the corresponding component, which may ensure a secure connection and may ensure that the components are connected easily and efficiently. The secure connection may also enable the coupled devices to support an increased load. Figs. 2A to 2C are variants of a coupling device according to embodiments of aspects of the invention. The coupling devices of Figs. 2A to 2C may be complementary devices to those of Figs. 1A to ID. That is, the coupling devices of Figs. 2A to 2C may be configured to engage with the coupling devices of Figs. 1A to ID. The coupling devices of Figs. lAto ID may correspond to the coupling device discussed above and the coupling devices of Figs. 2A to 2C may correspond to the complementary coupling device discussed above, or vice versa. The coupling devices of Figs. 1A to ID may correspond to the first coupling device of the coupling arrangement discussed above and the coupling devices of Figs. 2A to 2C may correspond to the second coupling device of the coupling arrangement discussed above, or vice versa. The coupling devices of Figs. 1A to ID may correspond to the first coupling device of the coupling system discussed above and the coupling devices of Figs. 2A to 2C may correspond to the second coupling device of the coupling system discussed above, or vice versa. Fig. 2A is a coupling device according to an embodiment of an aspect of the invention. The coupling device comprises a base plate 21, a first wall 22, a second wall 23 and a capping piece 24a. The first wall 22 and the second wall 23 extend from the base plate 21 and are perpendicular to the face of the base plate 21. The capping piece 24a extends from the face of the base plate 21 and is provided perpendicular to the base plate 21. The capping piece 24a is also perpendicular to the first wall 22 and the second wall 23. The first wall 22 and the second wall 23 are connected to the capping piece 24a. When viewed from the end opposite to the capping piece 24a, the coupling device has an F shape profile. The first wall 22 is provided with a first aperture 25 and the second wall 23 is provided with a second aperture 26. The first aperture 25 and the second aperture 26 are aligned and may be configured to receive a pin. A channel is defined between the first wall 22 and the second wall 23. The first wall 22 may be provided on an outer edge of the base plate 21, and the second wall 23 may be provided at a distance in from an opposing edge of the base plate 21. The capping piece 24a comprises a notch 241 on at least one outer edge. As can be seen through comparison of, for example, Fig. 1A and Fig. 2A, the devices are a mirrored about an axis in line with the first wall. The devices are otherwise the same. The coupling devices of Figs. 1A to ID may be referred to as left hand coupling devices and the of Figs. 2A to 2C may be referred to as right hand devices. The device of Fig. 2A corresponds to the device of Fig. 1A. The device of Fig. 2B corresponds to the device of Fig. IC. The device of Fig. 2C corresponds to the device of Fig. ID. The capping piece 24b of the coupling device of Fig. 2B has a different configuration to the capping piece 24a of Fig. 2A. Capping piece 24b comprises an engagement section which extends from the capping piece 24b in a direction opposite to the direction from which the first wall 22 and the second wall 23 extend from the capping piece 24b. The capping piece 24b comprising the engagement section may be considered as an extended capping piece 24b. The capping piece 24b may be extended to provide an engagement section in order to engage with another component, such as, for example, a connecting member. Fig. 2C is a coupling device according to an embodiment of an aspect of the invention. The capping piece 24c of the coupling device of Fig. 2C has a different configuration to the capping piece 24a of Fig. 2A and the capping piece 24b of the coupling device of Fig. 2B. Capping piece 24c comprises an engagement section which extends from the capping piece 24c in a direction opposite to the direction from which the first wall 22 and the second wall 23 extend from the capping piece 24c. The capping piece 24c comprising the engagement section may be considered as an extended capping piece 24c. The engagement section of capping piece 24c differs from that capping piece 24b in that the engagement section comprises an aperture 242. The aperture 242 may be configured to receive a pin (e.g. a locking pin or other fixing means, such as a locking bolt or a locking screw). Furthermore, the edges of the engagement section of capping piece 24c are rounded. This may be to better engage with a corresponding component. The capping piece 24c also comprises a first recess 243a and a second recess 243b. Each of the recesses may be configured to receive a seam of the connecting member. Fig. 3 A is a coupling arrangement according to an embodiment of an aspect of the invention. In Fig. 3 A, the coupling arrangement is in the coupled position, such that the outer profile of the coupling arrangement is substantially uniform. In particular, the elements of the coupling devices that interact provide a substantially uniform shape. The coupling arrangement in the coupling position therefore provides a unitary piece, solid piece or block piece. The coupling arrangement of Fig. 3 A comprises a first coupling device 31 and a second coupling device 32. Fig. 3B is a different view of the coupling arrangement of Fig. 3 A comprising first coupling device 31 and second coupling device 32. The coupling arrangements of Fig. 3 A to 3 G may correspond to the coupling arrangement discussed above and the coupling devices 31,32 may correspond to the first coupling device of the coupling arrangement discussed above and the second coupling device of the coupling arrangement discussed above, or vice versa. The coupling arrangement has a substantially rectangular prism external profile, at least in the portions relating to elements of the devices that engage. For example, the capping piece of the second coupling device 32 may extend in a direction opposite to the direction of the first coupling device 31 so as to provide an engagement potion. The profile of the engagement section may be different to the rest of the coupling arrangement. The extended capping piece may be configured to engage with another component of the coupling system, such as a connecting member. The connecting member may be length of box section into which the extended capping piece (the engagement section) is configured to be inserted. For example, the connecting member may be a 100mm x 100mm square hollow section (SHS) and the engagement section may be configured to be received in the SHS. The dimensions of the connecting member may be such that, when connected to the coupling arrangement, the connecting member continues the substantially uniform outer profile of the coupling arrangement. Fig. 3C is a coupling arrangement according to an embodiment of an aspect of the invention. The coupling arrangement of Fig. 3C comprises a first coupling device 31 and a second coupling device 32. Fig. 3C shows the coupling arrangement as the first coupling device 31 and second coupling device 32 are being separated to move from the coupled position to a decoupled position. Fig. 3D is a coupling arrangement according to an embodiment of an aspect of the invention. The coupling arrangement of Fig. 3D comprises a first coupling device 31 and a second coupling device 32. Fig. 3D shows the first coupling device 31 and the second coupling device 32 of the coupling arrangement in the decoupled position. The coupling device 31 comprises a base plate 311, a first wall 312, a second wall 313 and a capping piece 314. The coupling device 32 comprises a base plate 321, a first wall 322, a second wall 323 and a capping piece 324. As can be seen, the channel defined by the first wall 312 and the second wall 313 of the first device 31 is configured to receive the second wall 323 of the second device 32. The channel defined by the first wall 322 and the second wall 323 of the second device 32 is configured to receive the second wall 313 of the first device 32. As can be seen, an overhang section of the base plate 311 defined between the second wall 313 and an outer edge of the base plate 311 of the first device 31 is configured to receive the first wall 322 of the second device 32. An overhang section of the base plate 321 defined between the second wall 323 and an outer edge of the base plate 321 of the second device 32 is configured to receive the first wall 312 of the first device 31. Fig. 3E is a coupling arrangement according to an embodiment of an aspect of the invention. The coupling arrangement of Fig. 3E comprises a first coupling device 31 and a second coupling device 32. Fig. 3E shows the first coupling device 31 and the second coupling device 32 of the coupling arrangement in the decoupled position. The configuration of the capping piece of the first device 31 differs to the capping piece 314 of the first device 31 of Fig. 3D. Fig. 3F is a coupling arrangement according to an embodiment of an aspect of the invention. The coupling arrangement of Fig. 3F comprises a first coupling device 31 and a second coupling device 32. Fig. 3F shows the first coupling device 31 and the second coupling device 32 of the coupling arrangement in the decoupled position. The configuration of the capping piece of the first device 31 differs to the capping piece of the first device 31 of Fig. 3E. The side view of Fig. 3F shows how the walls of the first device 31 align with the walls of the second device 32 so that the devices can interact to move to the coupled position. Fig. 3G is a coupling arrangement according to an embodiment of an aspect of the invention. The coupling arrangement of Fig. 3G comprises a first coupling device 31 and a second coupling device 32. Fig. 3G shows the first coupling device 31 and the second coupling device 32 of the coupling arrangement in the decoupled position. Fig. 3G further shows how different variants of the coupling devices (e.g. with different capping piece configurations) can be aligned to move from the decoupled position to the coupled position. As can be seen from Figs. 3 A to 3G, the configuration of the capping pieces of the devices is independent of the engagement of the devices. That is, the configuration of a capping piece of a coupling device does not affect its ability to engage with another coupling device. Fig. 4A is a coupling system according to an embodiment of an aspect of the invention. The coupling system comprises a first coupling device 41, a second coupling device 42 and a bridging piece 43. The bridging piece comprises a top plate 433, a bridging first wall 431 extending from the top plate 433, a bridging second wall 432 extending from the top plate 433 and a bridging channel 435 defined between the bridging first wall 431 and the bridging second wall 432. The bridging piece 43 also comprises a top aperture 434 configured to receive an upper connecting piece. The bridging piece further comprises a plurality of bridging apertures 436. For example, the bridging first wall 431 comprises two first bridging apertures 436 and the bridging second wall 432 comprises two second bridging apertures 436 aligned with the respective first bridging apertures 436. The capping piece of the first coupling device 41 is received in an opening in the bridging first wall 431 of the bridging piece 43. The capping piece of the second coupling device 42 is received in an opening in the bridging second wall 432 of the bridging piece 43. The first coupling device 41 and the second coupling device 42 do not protrude into the bridging channel defined by the bridging first wall 431 and the bridging second wall 432. That is, the respective capping pieces of the first coupling device and the second coupling device do not extend through the openings into the channel defined between the bridging walls. Fig. 4B is a coupling system according to an embodiment of an aspect of the invention. The coupling system of Fig. 4B is the same as that of Fig. 4A except that it further comprises an upper connecting piece 44. The upper connecting piece 44 is received in the top aperture 434. The upper connecting piece 44 may be configured to receive a support piece, upper support piece or top support piece. The coupling system of Figs. 4A and 4B may correspond to the coupling system discussed above. The coupling device 41 may correspond to the first coupling device discussed above and the coupling device 42 may correspond to the second coupling device discussed above, or vice versa. Figs. 5A to 5G show a coupling system according to an embodiment of an aspect of the invention. Figs. 5A to 5G relate to the same coupling system but in each figure one or more components have been removed to demonstrate how the components are connected. Fig. 5 A shows a coupling system according to an embodiment of an aspect of the invention. The coupling system comprises multiple coupling devices 51, a bridging piece 52, multiple connecting members 53, multiple locking pins 54 and a support piece 55. In Fig. 5B the support piece 55 has been removed. The support piece 55 was connected to the upper connecting piece 521 of the bridging piece 52. In Fig. 5C the connecting members 53 have been removed. Each of the connecting members were connected to a coupling device 51. Fig. 5C shows all of the six coupling devices 5 la-51 f. The coupling devices are arranged in coupling arrangement pairs. The coupling arrangement comprising coupling devices 51e and 5 If is provided in the bridging channel of the bridging piece 52. Coupling device 51b of coupling arrangement 51a and 51b is connected to a first wall of the bridging piece 52. Coupling device 51c of coupling arrangement 51c and 5 Id is connected to a second wall of the bridging piece 52. The comparison of Figs. 5B and 5C demonstrate how the locking pins are used, in conjunction with the relevant apertures, to connect the connecting members 53 to the coupling devices 51e and 5 If and the bridging piece 52. In Fig. 5D the bridging piece 52 has been removed. Fig. 5D provides a better view of all of the six coupling devices 5 la-5 If, which are provided in three coupling arrangements: 51a and 51b; 51c and 51d; and 51e and 51f. Fig. 5D shows how each coupling arrangement is secured together by a respective locking pin 54. In Fig. 5E the locking pins have been removed to provide a better view of the coupling arrangements. The comparison of Figs. 5D and 5F show how the coupling devices 5 la-5 If are provided with apertures which are configured to receive the locking pins 54. In Fig. 5F coupling devices 51b and 5Id have been removed. This shows how the coupling arrangements 51a and 51b, and 51c and 51d were provided, with the relevant elements of the devices interlocking to provide the respective coupled pair. In Fig. 5G coupling device 5 If has been removed. This shows how the coupling arrangement 51e and 5 If were provided similarly to the other coupling arrangements, with the relevant elements of the devices interlocking to provide the coupled pair. The coupling system according to embodiments of aspects therefore comprises multiple coupling devices arranged in coupling pairs. Each pair is made of two corresponding coupling devices, with one of the corresponding device mirrored about an outer edge to provide the other corresponding device. The corresponding devices slot together in a manner which may enable the coupling system, and a modular structure comprising the coupling system, to be assembled quickly and efficiently. The corresponding devices may also allow for the devices to be coupled in a straightforward and repetitive fashion, and in a way which may reduce the overall number of different components that the modular structure comprises. Fig. 6 shows a modular structure according to an embodiment of an aspect of the invention. The modular structure of Fig. 6 comprises a first coupling system 6 land a second coupling system 62. The coupling systems 61, 62 are equivalent to the coupling system of Fig. 5A. The coupling system 61 is connected to the coupling system 62 via connecting member 63a. similarly, further coupling systems could be connected via connecting members 63b to 63f to provide a repetitive, grid-like modular structure. Fig. 6 shows how the structure may be assembled in a repetitive manner which may allow for quick and efficient assembly and / or disassembly. Fig. 7 shows a modular structure according to an embodiment of an aspect of the invention. The modular structure of Fig. 7 is the same as that of Fig. 6 except the grid has been extended to comprise a plurality of coupling systems 71. As can be seen from Fig. 7, the coupling systems 71 are connected by a plurality of connecting members 72a and 72b. In some parts of the grid system, connecting members 72a are provided. In other parts, they are not. These connecting members 72a may be referred to as lateral connecting members 72a. Such connecting members may be included or omitted depending on the load requirements of the structure and / or bracing requirements. If the lateral connecting members 72a between coupling systems 71 are omitted, then the outer coupling devices of the coupling systems 71, which are configured to engage with the lateral connecting members 72a, may also be omitted, e.g. coupling devices 51a and 51 d in Figs. 5A to 5E. The other connecting members 72b may be referred to as longitudinal connecting members 72b. The modular structure may be provided as a roof structure, such as, for example, a roof structure for a staging system. A roof covering may be provided on the modular structure, supported by the upper support pieces of the coupling systems 71. The upper supports pieces correspond to support piece 55 in Fig. 5A. The coupling device, coupling arrangement and coupling system may be any size and the dimensions of the components and the various parts of each component may be application specific. The dimensions may be determined by the required size of the modular structure, the required shape of the structure and / or the load that the structure is required to support. For example, a larger structure and a higher required load may require larger components. All of the components may be scaled such that their relative size to the other components remains unchanged. The modular nature allows for a grid system to be built in a repeat manner, with a coupling pair or a coupling arrangement provided in cooperation with 2 or 4 connecting members (which may also be referred to as struts or trusses). That is, the connecting members may be arranged at either 2 opposing sides of a coupling arrangement or at 4 opposing sides of a coupling arrangement. This is shown, for example, in Fig. 7 in which lateral connecting members 72a are provided between some coupling systems 71, but not between other coupling systems 71. The number of these lateral connecting members 72a in the grid system may depend on the application of the structure and / or the load requirements of the structure. For example, a grid structure may be provided that is six longitudinal connecting members 72b in length (six cross stage trusses) and three lateral connecting members 72a in width. A coupling system 71 may be provided at each junction between longitudinal connecting members 72b, which would provide a total of 28 pairs of coupling devices (coupling systems). The lateral connecting members 72a may be provided between the coupling systems 71 at each section of the grid system, or may be provided, for example, at every other section, as shown in Fig. 7. Such a structure in this configuration may allow for 10 Tonnes of load to be added to each cross stage line (primary line) of truss, to an accumulated total of 120 Tonnes within the main grid and a further 50 Tonnes of load within each of the two PA grids. The PA grids are the two smaller grid sections on the sides of the main structure, and are referred to as such because they are frequently use, in the context of a staging structure, to hang PA speakers at a live event This may be more than 20% extra load than comparable systems in the industry can offer. Further to this point, through simple reconfiguration of this modular system we can achieve even greater load capacity improvements. For example, if it is necessary for a structure to bear more weight in specific areas, the component modular parts may be reconfigured to allow for increased strength and load bearing in these zones. For example, by introducing more trusses (connecting members) between the coupling devices. Such an applications may, for example, be in a staging structure when a production or show requires more weight to be hung from the roof in specific areas. Similarly, if a larger or smaller structure is required, then the repetition of the grid system may be increased or decreased to meet the required size and load requirements. Embodiments of aspects may provide a coupling device, coupling arrangement and coupling system which may be used in a modular structure, such as, for example, a staging structure. The configuration of the devices may enable them to be connected in such a way that allows for a modular structure to be able to be assembled and disassembled quickly and efficiently. The components may also allow for the disassembled structures to be small in size so that less space is required to transport the structure between locations. Embodiments of aspects may reduce the required truck capacity to transport the structure compared to known staging systems. The load capacity may also be increased and the build time may be reduced. Embodiments of aspects may be applied to any field which uses modular and / or temporary structures, such as, for example, staging structures. The above-described embodiments of aspects may advantageously be used independently of any other of the embodiments or in any feasible combination with one or more others of the embodiments. Variations to the disclosed embodiments may be understood and effected by those skilled in the art in practicing the principles and techniques described herein, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does 5 not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope. 10

Claims

1. A coupling device for a modular structure, the coupling device comprising:a base plate;a first wall extending from the base plate;a second wall extending from the base plate;a channel defined between the first wall and the second wall and configured to receive a first portion of a complementary coupling device; anda capping piece extending from the base plate.

2. The coupling device of claim 1, whereinthe first wall extends from the base plate along a first outer edge of the base plate so as to align with the first outer edge of the base plate;the second wall extends from the base plate along a middle section of the base plate between the first outer edge of the base plate and a second outer edge of the base plate so as to not align with the first outer edge of the base plate or the second outer edge of the base plate, thereby defining an overhang section of the base plate between the second wall and the second outer edge of the base plate; andthe overhang section of the base plate is configured to engage with a second portion of the complementary coupling device.

3. The coupling device of claim 2, whereinthe width of the overhang section of the base plate between the second wall and the second outer edge of the base plate corresponds to the width of the first wall.

4. The coupling device of any preceding claim, whereinthe width of the channel defined between the first wall and the second wall corresponds to the width of the second wall.

5. The coupling device of any preceding claim, whereinthe first wall comprises a first aperture;the second wall comprises a second aperture aligned with the first aperture; andthe first aperture and the second aperture are configured to receive a locking pin.

6. The coupling device of any preceding claim, whereinthe capping piece extends from the base plate along a third outer edge of the base plate so as to align with the third outer edge of the base plate.

7. The coupling device of any preceding claim, whereinthe first wall extends from the capping piece along a second outer edge of the capping piece so as to align with the second outer edge of the capping piece; anda top edge of the first wall extends from the face of the capping piece at a point of the capping piece between a first outer edge of the capping piece and a third outer edge of the capping piece that is opposite to the first outer edge of the capping piece, thereby defining an overhang section of the capping piece between the top edge of the first wall and the third outer edge of the capping piece.

8. The coupling device of claim 7, whereinthe width of the overhang section of the capping piece between the top edge of the first wall and the third outer edge of the capping piece corresponds to the depth of the base plate.

9. The coupling device of any preceding claim, whereinthe capping piece comprises an engagement section that extends from the capping piece in a direction opposite to the extension of the base plate from the capping piece; and the engagement section is configured to engage with a connecting member.

10. The coupling device of claim 9, wherein the engagement section comprises an engagement aperture configured to receive a locking pin.

11. The coupling device of claim 10, wherein the engagement aperture passes through the engagement section.

12. A coupling arrangement for a modular structure, the coupling arrangement comprising:a first coupling device comprising: a first device base plate; a first device first wall extending from the first device base plate; a first device second wall extending from the first device base plate; a first device channel defined between the first device first wall and thefirst device second wall; and a first device capping piece extending from the first device base plate; anda second coupling device comprising: a second device base plate; a second device first wall extending from the second device base plate; a second device second wall extending from the second device base plate; a second device channel defined between the second device first wall and the second device second wall; and a second device capping piece extending from the second device base plate, whereinthe first coupling device and the second coupling device are configured to engage so as to form a unitary piece when in a coupled positon; andthe first device channel is configured to receive the second device second wall and the second device channel is configured to receive the first device second wall when in the coupled position.

13. The coupling arrangement of claim 12, wherein the external profile of the first coupling device and the second coupling device when in the coupled position has a substantially rectangular prism shape.

14. The coupling arrangement of claim 12 or 13, whereinthe first device first wall comprises a first device first aperture;the first device second wall comprises a first device second aperture aligned with the first device first aperture;the second device first wall comprises a second device first aperture;the second device second wall comprises a second device second aperture aligned with the second device first aperture;the first device first aperture, the first device second aperture, the second device first aperture and the second device second aperture are aligned when in the coupled position and are configured to receive a locking pin.

15. The coupling arrangement of any of claims 12 to 14, wherein the second coupling device is a mirror of the first coupling device about a first outer edge of the first device base plate, along the length of the first device first wall.

16. The coupling arrangement of any of claims 12 to 15, whereinthe first coupling device is the coupling device of any of claims 1 to 11; andthe second coupling device is the complementary coupling device of any of claims1 to 11.

17. The coupling arrangement of claim 16, whereinthe first portion of the complementary coupling device is the second device second wall; andthe second portion of the complementary coupling device is the second device first wall.

18. A coupling system for a modular structure, the coupling system comprising:a first coupling device comprising: a first device base plate; a first device first wall extending from the first device base plate; a first device second wall extending from the first device base plate; a first device channel defined between the first device first wall and the first device second wall; and a first device capping piece extending from the first device base plate;a second coupling device comprising: a second device base plate; a second device first wall extending from the second device base plate; a second device second wall extending from the second device base plate; a second device channel defined between the second device first wall and the second device second wall; and a second device capping piece extending from the second device base plate;a bridging piece comprising: a top plate; a bridging first wall extending from the top plate; a bridging second wall extending from the top plate; and a bridging channel defined between the bridging first wall and the bridging second wall, whereinthe bridging first wall is configured to receive the first device capping piece of the first coupling device when in a coupled position; andthe bridging second wall is configured to receive the second device capping piece of the second coupling device when in the coupled position.

19. The coupling system of claim 18, wherein the second coupling device is a mirror of the first coupling device about a first outer edge of the first device base plate, along the length of the first device first wall.

20. The coupling system of claim 18 or 19, whereinthe first device base plate is proximate to the distal end of the bridging first wall when in the coupled position; andthe second device base plate is proximate to the proximal end of the bridging second wall when in the coupled position.

21. The coupling system of any of claims 18 to 20, whereinthe top plate of the bridging piece comprises a top aperture arranged between the bridging first wall and the bridging second wall; andthe top aperture is configured to receive an upper connecting piece.

22. The coupling system of any of claims 18 to 21, whereinthe bridging first wall comprises a first bridging aperture;the bridging second wall comprises a second bridging aperture aligned with the first bridging aperture; andthe first bridging aperture and the second bridging aperture are configured to receive a locking pin.

23. The coupling system of any of claims 18 to 22, comprising:the coupling arrangement of any of claims 12 to 17, whereinthe bridging channel is configured to receive the coupling arrangement; andthe coupling arrangement is in the coupled position when positioned in the bridging channel.

24. The coupling system of any of claims 18 to 23, wherein the first coupling device is the coupling device of any of claims 1 to 11.AMENDMENTS TO THE CLAIMS HAVE BEEN FILEDAS FOLLOWS:CLAIMS1. A coupling arrangement for a modular structure, the coupling arrangement comprising:5 a first coupling device comprising:a first device base plate;a first device first wall extending from the first device base plate;a first device second wall extending from the first device base plate;a first device channel defined between the first device first wall and the first10 device second wall; anda first device capping piece extending from the first device base plate; anda second coupling device comprising:a second device base plate;a second device first wall extending from the second device base plate;15 a second device second wall extending from the second device base plate;a second device channel defined between the second device first wall and the second device second wall; anda second device capping piece extending from the second device base plate,00 wherein-j— 20 the first coupling device and the second coupling device are configured to engage soas to form a unitary piece when in a coupled position; andthe first device channel is configured to receive the second device second wall and the second device channel is configured to receive the first device second wall when in the coupled position.

252. The coupling arrangement of claim 1, wherein the external profile of the first coupling device and the second coupling device when in the coupled position has a substantially rectangular prism shape.30 3. The coupling arrangement of claim 1 or 2, whereinthe first device first wall comprises a first device first aperture;the first device second wall comprises a first device second aperture aligned with the first device first aperture;the second device first wall comprises a second device first aperture;the second device second wall comprises a second device second aperture aligned with the second device first aperture; andthe first device first aperture, the first device second aperture, the second device first aperture and the second device second aperture are aligned when in the coupled position.

4. The coupling arrangement of claim 3, further comprising:an arrangement locking pin, whereinthe first device first aperture, the first device second aperture, the second device first aperture and the second device second aperture are configured to receive the arrangement locking pin when in the coupled position.

5. The coupling arrangement of any preceding claim, wherein the second coupling device is a mirror of the first coupling device about a first outer edge of the first device base plate, along the length of the first device first wall.

6. The coupling arrangement of any preceding claim, whereinthe first device first wall extends from the base plate along a first outer edge of the first device base plate so as to align with the first outer edge of the first device base plate;the first device second wall extends from the first device base plate along a middle section of the first device base plate between the first outer edge of the first device base plate and a second outer edge of the first device base plate so as to not align with the first outer edge of the first device base plate or the second outer edge of the first device base plate, thereby defining an overhang section of the first device base plate between the first device second wall and the second outer edge of the first device base plate; andthe overhang section of the first device base plate is configured to engage with the second device first wall.

7. The coupling arrangement of claim 6, whereinthe width of the overhang section of the first device base plate between the first device second wall and the second outer edge of the first device base plate corresponds to the width of the first device first wall.

8. The coupling arrangement of any preceding claim, whereinthe width of the first device channel defined between the first device first wall and the first device second wall corresponds to the width of the first device second wall.

9. The coupling arrangement of any preceding claim, whereinthe first device first wall comprises a first aperture;the first device second wall comprises a second aperture aligned with the first aperture.

10. The coupling arrangement of any preceding claim, whereinthe first device capping piece extends from the first device base plate along a third outer edge of the first device base plate so as to align with the third outer edge of the first device base plate.

11. The coupling arrangement of any preceding claim, whereinthe first device first wall extends from the first device capping piece along a second outer edge of the first device capping piece so as to align with the second outer edge of the first device capping piece; anda top edge of the first device first wall extends from the face of the first device capping piece at a point of the first device capping piece between a first outer edge of the first device capping piece and a third outer edge of the first device capping piece that is opposite to the first outer edge of the first device capping piece, thereby defining an overhang section of the first device capping piece between the top edge of the first device first wall and the third outer edge of the first device capping piece.

12. The coupling arrangement of claim 11, whereinthe width of the overhang section of the first device capping piece between the top edge of the first device first wall and the third outer edge of the first device capping piece corresponds to the depth of the first device base plate.

13. The coupling arrangement of any preceding claim, whereinthe first device capping piece comprises an engagement section that extends from the first device capping piece in a direction opposite to the extension of the first device base plate from the first device capping piece.

14. The coupling arrangement of claim 13, further comprising:a connecting member, whereinthe engagement section is configured to engage with the connecting member.

15. The coupling arrangement of claim 13 or 14, further comprising:a connecting member locking pin, whereinthe engagement section comprises an engagement aperture configured to receive the connecting member locking pin.

16. The coupling arrangement of claim 15, wherein the engagement aperture passes through the engagement section.

17. The coupling arrangement of any preceding claim, further comprisinga bridging piece comprising:a top plate;a bridging first wall extending from the top plate;a bridging second wall extending from the top plate; anda bridging channel defined between the bridging first wall and the bridging second wall, whereinthe bridging first wall is configured to receive the first device capping piece of the first coupling device when in the coupled position;the bridging second wall is configured to receive the second device capping piece of the second coupling device when in the coupled position;the bridging channel is configured to receive the coupling arrangement; andthe coupling arrangement is positioned in the bridging channel when in the coupled position.

18. The coupling arrangement of claim 17, whereinthe first device base plate is proximate to the distal end of the bridging first wall when in the coupled position; andthe second device base plate is proximate to the proximal end of the bridging second wall when in the coupled position.

19. The coupling arrangement of claim 17 or 18, wherein18 09 24the top plate of the bridging piece comprises a top aperture arranged between the bridging first wall and the bridging second wall.

20. The coupling arrangement of claim 19, further comprising:an upper connecting piece, whereinthe top aperture is configured to receive the upper connecting piece.

21. The coupling arrangement of any of claims 17 to 20, whereinthe bridging first wall comprises a first bridging aperture; andthe bridging second wall comprises a second bridging aperture aligned with the first bridging aperture.

22. The coupling arrangement of claim 21, further comprising:a bridging piece locking pin, whereinthe first bridging aperture and the second bridging aperture are configured to receive the bridging piece locking pin.

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