Technical Field of the Invention

The present invention relates to portable building structures. In particular, but not exclusively, the invention concerns a portable building structure with movable walls and which retains an unswept area at all times.

Background to the Invention

A large variety of portable building structures are known.

Some temporary or semi-permanent building structures are provided in a kit of prefabricated components which are transported to the desired location and assembled on site. Such structures are typically used, for example, as temporary offices or stores on a building site.

One problem with the known prefabricated structures of this type is that if they are transported already assembled, they tend to be relatively bulky, which requires a relatively large vehicle for transport. On the other hand, if the structure is transported in a dismantled state, there is a risk that one or more components may go astray during storage or transport and/or there could be difficulties in assembling such a complex product.

Portable prefabricated structures, such as mobile homes, have been used to provide temporary or semi-permanent building space. However, as the size of the structure increases, the ease with which they can be transported is reduced. Large structures have to be divided into parts and transported separately on oversized trucks. When not in use, the structures require significant space for storing.

A number of folding structures have been devised to improve the transportability and space problems. Two structures are shown in U.S. Patent Nos. 4,545,171 and 4,891,919.

U.S. Patent No. 4,545,171 discloses a structure having hinged roofs, floors and walls. Although its collapsible design makes it easier to transport, this structure requires specialized handling in transit. The structure also requires a concrete foundation, which can defeat any advantage for use as a temporary structure. The structure is designed to be permanently installed with various components being attached with nails and bolts. The interior surfaces, such as walls, paint, wallpaper, floors, and carpets are installed after assembly.

U.S. Patent No. 4,891,919 discloses a house erected from and supported by a standard size cargo shipping container with hinged walls and floor panels. After the wall and floor panels are unfolded, the roof and end walls, which are transported inside the container, are removed and assembled to complete the house. Although transportation of the structure is simplified by the use of a standard size cargo shipping container, the complexity of assembly is increased through the use of the separable parts for the roof and walls which need to be lifted into position and attached. The description states that assembly generally will take five days with four people. A specialized foundation is required to support the floor panels above the level of the container bottom. The arrangement of the hinges necessitates additional filler pieces to complete the floor and side walls.

Embodiments of the invention seek to at least partially overcome or ameliorate any one or more of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

Summary of the Invention

According to a first aspect of the invention there is provided a portable building structure comprising:

1) a main frame with; a) a roof; b) a floor; and c) at least one upright located at each end of the main frame between the roof and floor, the at least one of the upright of each pair spaced inwardly from a lateral edge of the roof and the floor, to create a recess, top and bottom of the main frame, on at least one lateral side;

2) at least one movable roof structure mounted relative to the recess for movement between a raised use position and a folded storage position in which the at least one movable roof structure at least partially closes a lateral side of the main frame; 3) at least one movable floor structure mounted relative to the recess for movement between a lowered use position and a folded storage position in which the at least one movable floor structure at least partially closes the lateral side of the main frame; and

4) at least one moveable wall structure including: a) an end support; b) a pair of folding frame walls, one of the pair of folding frame walls at each end of the main frame, one of each pair of frame walls mounted relative to the recess, a second of each pair mounted to the end support, the folding frame walls mounting the end support for sliding movement from a storage position within the recess, to a use position between an outer end of the at least one movable roof structure and at least one movable floor structure when deployed.

Providing a main frame with a recess on at least one and preferably both lateral sides, allows the mounting of at least one movable wall structure within the recess, and the at least one movable roof structure and/or at least one movable floor structure at least partially within the recess. The at least one movable wall structure can remain upright during storage, deployment and use. The at least one movable roof structure and/or at least one movable floor structure can move between the storage and use position mounted relative to the main frame. The features and configuration of the portable building structure of the invention minimises the footprint of the portable building structure in the storage condition. The features and configuration of the portable building structure provides an internal space in the main frame which is unswept by any of the movable components of the portable building structure, at any time in the storage, deployment and use of the portable building structure due to the mounting of the components relative to the recess.

In the context of the present description and claims, the term ‘unswept’ means that the movable components of the portable building structure do not pass over/through that portion of the internal space or area in the main frame, during movement. The components of the portable building structure are preferably mounted outside the unswept area. The components of the portable building structure move outside the unswept area at all times. The portable building structure of the present invention is typically transportable. The building structure will typically be transported in a storage configuration and once on site, will typically be expanded or deployed into a use configuration.

The portable building structure is particularly useful for mobile buildings used for ‘drop in’ operations such as a field hospital for example. One or more required pieces of equipment can be installed in the unswept area, fixed in position and due to the configuration of the portable building structure, the fixed equipment will not require repositioning during deployment once the portable building structure has been delivered on site.

The unswept area in the main frame of the building structure will preferably provide an area in which to store items within the structure, but the items can be stored in such a way that they do not need to be moved during the deployment of the building structure or during use in order to deploy the building structure.

Preferably, all of the walls of the portable building structure are provided as frame walls, formed from a number of frame members attached to or relative to one another.

In use, the portable building structure will typically be moved into a deployed or use configuration, and one or more wall panels will normally be mounted relative to the preferred frame walls to enclose the building structure. Components of the portable building structure of the present invention, including the main frame, the end support and the folding frame walls, will normally be provided as open frame components relative to which one or more wall panels can be mounted as necessary. The appearance and/or function of the building structure can preferably be changed by changing the wall panels mounted relative to the frame.

The building structure will preferably be fitted with a number of ISO corner castings. The number and positioning of the ISO comer castings will preferably be such that standard handling equipment can be used to handle the portable building structure when in the storage configuration. Preferably, an ISO corner casting is provided at each of the upper and lower, outer ends of the main frame. The portable building structure preferably includes a main frame with a roof, a floor and at least one upright located at each end of the main frame between the fixed roof and fixed floor. In use, the main frame will preferably be positioned centrally between a pair of deployable, movable wall structures, one on either lateral side of the main frame. More than one upright may be provided at each end of the main frame. In an embodiment, a pair of uprights may be provided at each end of the main frame.

The main frame is preferably constructed using a number of members attached together to form the main frame. Typically, the main frame is formed by provision of a fixed roof and a fixed floor and then spacing them apart using four uprights, two at either end. The sides of the main frame will typically be open, with the top of the main frame closed by the fixed roof and the bottom of the main frame closed by the fixed floor in the storage condition.

The fixed roof will preferably include one or more roof panels provided relative to a surround frame. The surround frame will typically be generally rectangular. The surround frame will normally be formed from a pair of spaced apart, substantially parallel side members and a pair of spaced apart substantially parallel end members. A comer casting is preferably provided at each of the comers of the surround frame of the fixed roof. The side members of the fixed roof surround frame will preferably be spaced inwardly, preferably evenly, from the lateral extremity of the main frame.

A single roof panel will preferably be provided within the surround frame. The roof panel(s) may be formed of any material, with a metal material being preferred. This will preferably increase the robustness of the building structure in both the use and storage conditions.

The fixed floor will preferably include one or more floor panels provided relative to a surround frame. The surround frame will typically be generally rectangular. The surround frame will normally be formed from a pair of spaced apart, substantially parallel side members and a pair of spaced apart substantially parallel end members. A comer casting is preferably provided at each of the comers of the surround frame of the fixed floor. The side members of the fixed floor surround frame will typically be located such that an outer wall of the side members is positioned adjacent to the lateral extremity of the main frame. A single floor panel will preferably be provided within the surround frame. The floor panel(s) may be formed of any material, with a metal material being preferred. This will preferably increase the robustness of the building structure in both the use and storage conditions.

Each of the surround frames will typically be formed from a number of frame members which are attached together. Each of the frame members will typically be elongate. Each of the frame members are preferably made of a robust and strong material and a light metal is preferred. Although each of the frame members may have any cross-sectional shape, a rectangular hollow section (RHS) is preferred. Typically, the surround frame members are permanently attached to or relative to one another using an appropriate attachment method such as welding if the members are metal.

The fixed roof and the fixed floor are typically separated by a pair of spaced apart uprights located at each end of the main frame between the fixed floor and the fixed roof. Preferably, the pair of spaced apart uprights are located between the end members of the surround frames of the fixed floor and fixed roof. Preferably, both of the pair of spaced apart uprights located at each end of the main frame are spaced inwardly from the respective lateral edge of the main frame to create a recess on each lateral side of the main frame, at the top and the bottom. Typically, the recess will extend over the length of the main frame.

Each of the uprights is preferably elongate. Each of the uprights is preferably manufactured from a strong and robust material. A light metal is preferred. Although each of the uprights may have any cross-sectional shape, it is preferred that each of the uprights is a rectangular hollow section (RHS).

Bracing may be provided between each of the uprights and the respective end member of the surround frame of the fixed floor and/or fixed roof. In a preferred form, the bracing is or includes an angled bracket or plate, for example.

The pairs of spaced apart uprights located at each end of the main frame will preferably define a generally rectangular area between them within the main frame, which is the unswept area. The unswept area will typically extend over the entire height of the main frame between the fixed floor and the fixed roof, creating in affect, an unswept volume within the main frame. The other components of the portable building structure are preferably mounted relative to the main frame outside the uprights, or at least no further inwardly than the inner side of the uprights. The recess is typically defined between an outer side of the uprights on one lateral side of the main frame and the outer end of the end members of the fixed floor and fixed roof.

A runner or guide is preferably provided on an upper side of the or each end member of the surround frame of the fixed floor, in the recess area. The runner or guide provided on the upper side of each end member of the surround frame of the fixed floor in the recess area, preferably extends laterally over the length of the recess and the corner casting if provided.

A runner or guide is preferably provided on a lower side of the or each end member of the surround frame of the fixed roof, in the recess area. The runner or guide provided on the lower side of each end member of the surround frame of the fixed roof in the recess area, preferably extends laterally to the outer side of the side member of the surround frame, preferably part way across the comer casting, if provided.

As will be explained further below, the runner or guide will typically guide movement of the at least one movable wall structure. Preferably, the runner or guide is configured as a channel. The channel will typically be substantially U-shaped, having a pair of spaced apart, substantially parallel upstanding walls and a transverse linking web therebetween. Preferably, the ends of the substantially parallel upstanding walls are shaped in order to assist with clearance, particularly when the at least one movable roof structure and/or at least one movable floor structure are moved.

The portable building structure includes at least one movable roof structure mounted relative to the recess for movement between a raised, use position and a storage position in which the at least one movable roof structure at least partially closes a lateral side of the main frame. Preferably, the at least one movable roof structure will include at least one roof panel. A single roof panel extending over the length of the portable building structure and the height of the main frame is preferred. Providing a single roof panel of this size allows the height of the main frame to define the maximum span of the roof (the span of the roof can be smaller than the height of the main frame, but typically not any larger) but also to allow the roof panel to at least partially close a lateral side of the main frame when in the storage position. In an embodiment, the roof panel is substantially planar. The roof panel is preferably manufactured of a strong, robust material and whilst any material could be used, a light metal is preferred. This will preferably increase the robustness of the building structure in both the use and storage conditions.

Typically, a movable roof structure is provided on both lateral sides of the main frame. In situations where a pair of movable roof structures are provided, one on either lateral side of the main frame, this allows the deployed configuration of the portable building structure to be up to 3 times the volume of the main frame (of course depending upon the dimension of the main frame).

The at least one movable roof structure is preferably substantially planar. The at least one movable roof structure is preferably formed of an outer surround frame provided about, and surrounding a roof panel. The outer surround frame preferably includes a pair of spaced apart, substantially parallel side members and a pair of transversely extending, parallel, spaced apart end members. The surround frame will preferably be substantially rectangular.

A shaped corner portion is preferably provided at the respective inner corners of the surround frame. Typically, the comer portion will be substantially L-shaped. The corner portion will typically be provided to allow clearance for the movable roof structure about the corner casting, if the corner casting is provided. In a configuration, the inner side member of the surround frame of the movable roof structure is typically not full length, stopping short of the end members. The end members of the surround frame of the movable roof structure are typically not full width, stopping short of the inner side member. The inner side member and the end members are typically connected using an L-shaped corner structure to provide the clearance for the corner casting if provided. If no comer casting is provided, then no shaped corner portion will generally be required.

Preferably, the inner side member of the surround frame of the movable roof structure is mounted to the side member of the surround frame of the fixed roof of the main frame. Preferably, the inner side member is hinged to the side member of the surround frame of the fixed roof of the main frame. At least one hinge is provided. In a preferred embodiment, an elongate hinge preferably extends over the length of the inner side member. The elongate hinge preferably extends over the full length of the inner side member between the corner castings if provided. In this embodiment, the hinge may be a concealed hinge and/or what is often referred to as a piano hinge.

A runner or guide is preferably provided on an under side (when deployed) or inner side (when stored) of each end member of the surround frame of the movable roof structure. As will be explained further below, the runner or guide will typically guide movement of the at least one movable wall structure. Preferably, the runner or guide is configured as a channel. The channel will typically be substantially U-shaped, having a pair of spaced apart, substantially parallel upstanding walls and a transverse linking web therebetween. The runner or guide so provided is preferably aligned with the runner or guide provided on the underside of the upper end member of the main frame in the recess area. The ends of the substantially parallel walls of the channel are typically spaced from the substantially parallel walls of the adjacent channel located in the recess area in order to provide clearance for movement of the at least one movable roof structure. The ends of the substantially parallel walls of the channel may be shaped, preferably arcuate to enhance this clearance.

The runner or guide provided on an under side (when deployed) or inner side (when stored) of each end member of the surround frame of the movable roof structure will preferably extend into or over the open part of the shaped comer portion provided at an inner side of the at least one movable roof structure. When the at least one movable roof structure is in the deployed condition, the extension portion of the runner or guide will typically lie underneath the corner casting if provided.

In the use position, the at least one movable roof structure is preferably substantially horizontal. The at least one movable roof structure will preferably be substantially coplanar with the fixed roof of the main frame.

In the collapsed position, for storage and/or transport, the at least one movable roof structure is preferably substantially vertical. In this position, the at least one movable roof structure will preferably at least partially close a lateral side of the main frame. One or more sealing members or arrangements may be provided between the inner edge of the surround frame of the at least one movable roof structure and the fixed roof of the main frame.

One or more assistance mechanisms may be provided in relation to the at least one movable roof structure to provide assistance to a user in moving the at least one movable roof structure, particularly into the use position. Typically, the one or more assistance mechanisms may be or include one or more lifting springs, pneumatic springs or gas struts for example. Normally, the one or more assistance mechanisms may be provided between an upright of the main frame and an end frame member of the surround frame of the at least one movable roof structure.

If provided, it is preferred that the one or more assistance mechanisms are removably attachable. In an embodiment, a stub axle or connector may be provided on the frame members at either end of the one or more assistance mechanisms and the one or more assistance mechanisms may be provided with a ball socket or similar arrangement at each end, to be removably located relative to the stub axle or connector. The one or more assistance mechanisms may be used to assist the movement of the movable roof structure and then be removed whilst the building structure is in use.

One or more rest members or arrangements may be provided on the facing edges or surfaces of the surround frames of the at least one movable roof structure and the fixed roof of the main frame. In one form, a rest member is preferably provided on each of the facing edges or surfaces and extending over the length of the members.

The at least one movable roof structure is preferably mounted within the recess area of the main frame. The at least one movable roof structure is preferably received within the recess area between the fixed roof and fixed floor of the main frame, when in the storage or collapsed position.

The portable building structure comprises at least one movable floor structure mounted relative to the recess for movement between a lowered, use position and a storage position in which the at least one movable floor structure at least partially closes the lateral side of the main frame. Preferably, the at least one movable floor structure will include at least one floor panel. A single floor panel extending over the length of the portable building structure and the height of the main frame is preferred. Providing a single floor panel of this size allows the height of the main frame to define the maximum span of the floor (the span of the floor may be smaller than the height but not larger) but also to allow the floor panel to at least partially close a lateral side of the main frame when in the storage position. In an embodiment, the floor panel is substantially planar. The floor panel is preferably manufactured of a strong, robust material and whilst any material could be used, a light metal is preferred. This will preferably increase the robustness of the building structure in both the use and storage conditions, particularly because the at least one movable floor structure will generally be the outermost lateral structure when in the storage position.

Typically, a single movable floor structure is provided on both lateral sides of the main frame. In situations where a pair of movable floor structures are provided, one n either lateral side of the main frame, this allows the deployed configuration of the portable building structure to be up to 3 times the volume of the main frame (of course depending upon the dimension of the main frame).

The at least one movable floor structure is preferably substantially planar. The at least one movable floor structure is preferably formed of an outer surround frame provided about, and surrounding a floor panel. The outer surround frame preferably includes a pair of spaced apart, substantially parallel side members and a pair of transversely extending, parallel, spaced apart end members. The surround frame will preferably be substantially rectangular.

In an embodiment, the inner side member of the surround frame of the movable floor structure typically extends the full length of the movable floor structure and/or main frame.

Preferably, the inner side member of the surround frame of the movable floor structure is mounted to the side member of the surround frame of the fixed floor of the main frame. Preferably, the inner side member is hinged to the side member of the surround frame of the fixed floor of the main frame. At least one hinge is provided. In a preferred embodiment, an elongate hinge preferably extends over the length of the inner side member. The elongate hinge preferably extends over the full length of the inner side member between the corner castings if provided. In this embodiment, the hinge may be concealed hinge and/or what is often referred to as a piano hinge.

A runner or guide is preferably provided on an upper side (when deployed) or inner side (when stored) of each end member of the surround frame of the movable floor structure. As will be explained further below, the runner or guide will typically guide movement of the at least one movable wall structure. Preferably, the runner or guide is configured as a channel. The channel will typically be substantially U-shaped, having a pair of spaced apart, substantially parallel upstanding walls and a transverse linking web therebetween. The runner or guide so provided is preferably aligned with the runner or guide provided on the upper side of the lower end member of the main frame in the recess area. The ends of the substantially parallel walls of the channel are typically spaced from the substantially parallel walls of the adjacent channel located in the recess area, to provide clearance for movement of the at least one movable floor structure. The ends of the substantially parallel walls of the channel may be shaped, preferably arcuate to enhance this clearance.

In the use position, the at least one movable floor structure is preferably substantially horizontal. The at least one movable floor structure will preferably be substantially coplanar with the fixed floor of the main frame.

In the collapsed position, for storage and/or transport, the at least one movable floor structure is preferably substantially vertical. In this position, the at least one movable floor structure will preferably at least partially close a lateral side of the main frame.

One or more sealing members or arrangements may be provided between the inner edge of the surround frame of the at least one movable floor structure and the fixed floor of the main frame.

One or more assistance mechanisms may be provided in relation to the at least one movable floor structure to provide assistance to a user in moving the at least one movable floor structure, particularly into the storage position. Typically, the one or more assistance mechanisms may be or include one or more lifting springs, pneumatic springs or gas struts for example. Normally, the one or more assistance mechanisms may be provided between an upright of the main frame and an end frame member of the surround frame of the at least one movable floor structure. If provided, it is preferred that the one or more assistance mechanisms are removably attachable. In an embodiment, a stub axle or connector may be provided on the frame members and the one or more assistance mechanisms may be provided with a ball socket or similar arrangement at each end in order to be removably located relative to the stub axle or connector. The one or more assistance mechanisms may be used to assist the movement of the movable floor structure and then be removed whilst the building structure is in use.

One or more rest members or arrangements may be provided on the facing edges or surfaces of the surround frames of the at least one movable floor structure and the fixed floor of the main frame. In one form, a rest member is preferably provided on each of the facing edges or surfaces and extending over the length of the members.

In contrast with the at least one movable roof structure, the at least one movable floor structure is typically mounted relative to the main frame at an outer edge of the recess at a lower side of the main frame. The at least one movable floor structure will preferably be located outside the recess when in the folded or storage position. In addition, the at least one movable floor structure will typically lack the corner portions provided on the at least one movable roof structure in order to provide clearance for the corner castings if provided. The at least one movable floor structure will be located outside the at least one movable roof structure and will normally be deployed before the at least one movable roof structure when deploying the building structure and will be moved after the at least one movable roof structure when moving the building structure to the storage or transport condition.

The portable building structure comprises a moveable wall structure including an end support and a pair of folding frame walls, one of each pair of folding frame walls at each end of the main frame, one of each pair of frame walls mounted relative to the recess, a second of each pair of folding frame walls mounted to the end support, the folding frame walls mounting the end wall frame for sliding movement from a storage position within the recess, to a use position between an outer end of the at least one movable roof structure and at least one movable floor structure when deployed.

The end support may include an upright member. The end support may include an upright member at an outer end of each of the pair of folding frame walls. The end support may be provided as a part of each of the folding frame walls.

The end support of an embodiment may be or include an end wall frame.

The end wall frame is preferably mounted to an outer end of each of the pair of folding frame walls. The end wall frame preferably moves between the at least one movable roof structure and at least one movable floor structure, translating from the storage position to the use position once the at least one movable roof structure and at least one movable floor structure have been deployed. The end wall frame can be moved by an operator, which causes movement of the pair of folding frame walls, and/or one or both of the pair of folding frame walls can be moved, which causes movement of the end wall frame. The end wall frame will remain substantially vertical at all times during use, during deployment between the use position and the storage position (and vice versa and during storage.

The end wall frame is preferably formed from a pair of substantially vertical end members, at least one top rail and at least one bottom rail. Preferably, the bottom rail is removable from the end wall frame, particularly if the building structure is located relative to an adjacent building structure of the same configuration. This will typically enable a person within to walk between adjacent building structures without requiring them to step over the bottom rail.

One or more intermediate upright members may be provided between the substantially vertical end members. If the bottom rails is removed, then the one or more intermediate upright members will normally be removed as well.

The members of the end wall frame are preferably elongate. The members of the end wall frame are typically formed from a strong and robust material of which a light metal is preferred. Although the members may have any cross-sectional shape, preferably, each of the members is a rectangular hollow section. The end support is typically mounted on at least one roller or similar device to allow ease of movement. A roller is preferred due to the alignment aspect or rotation in only two directions. At least one roller may be provided at a lower end of each of the end supports.

Preferably, at least one roller is provided at a lower end of each of the substantially vertical end members of the end wall frame. This will typically support the end wall frame. At least one roller may be provided at an upper end of each of the substantially vertical end members of the end wall frame. The at least one roller will typically travel in a respective channel provided on the main frame (at the start of deployment and the end of the storage) and on the side members of the surround frame of the at least one movable roof structure and at least one movable floor structure.

The end support(s) is preferably load-bearing. When deployed, the end support(s) will preferably support the at least one movable roof structure above the at least one movable floor structure. The end support(s) will preferably support the at least one movable roof structure by abutment with the at least one movable floor structure.

Each of the at least one roller provided will preferably be load-bearing.

The end wall frame, where provided, is preferably load-bearing. When deployed, the end wall frame will preferably support the at least one movable roof structure above the at least one movable floor structure. The end wall frame will preferably support the at least one movable roof structure by abutment with the at least one movable floor structure.

The end wall frame will preferably be received within the recess area when in the storage position. The end wall frame is typically located inside the at least one movable roof structure when the portable building structure is in the storage condition.

As mentioned previously, once deployed, one or more wall panels can be mounted relative to the end wall frame in order to partially enclose the building structure.

A folding frame wall is preferably provided at each end of the main frame. A folding frame wall is preferably provided between each end of the main frame and the respective end of the end wall frame. Each folding frame wall is connected to the end wall frame such that movement of the end wall frame also moves each folding frame wall and vice versa. Each folding frame wall is preferably not supported directly by the at least one movable roof structure or the at least one movable floor structure. Preferably, each folding frame wall is supported by the end wall frame and the main frame. Each folding frame wall is typically supported between the end wall frame and an upright of the main frame.

Each of the pair of folding frame walls will preferably include at least two frame walls which fold relative to one another. Although more than two frame walls can be provided, a bifold configuration is preferred, with each of the pair of folding frame walls including two frame walls.

Preferably, a first frame wall of each pair of folding frame walls is mounted relative to the recess of the main frame. Typically, the first frame wall is mounted to an upright of the main frame. The first frame wall is preferably mounted relative to an outer side or surface of the upright. The first frame wall is preferably mounted relative to the upright using at least one hinge. Preferably two or more hinges are provided.

In an embodiment, at least one upper hinge and at least one lower hinge is provided between the first frame wall and the upright. Each of the hinges is preferably a concealed hinge but other types of hinge could be used such as a piano hinge for example. Each of the hinges preferably has at least an inner leaf attached to the upright and at least an outer leaf attached to the first frame wall. At least one of the inner leaf and outer leaf is preferably fixed in position relative to the upright. At least one of the inner leaf and outer leaf may be provided in a floating configuration in which the inner leaf or outer leaf can move vertically, both up and down (within limits), relative to the other frame wall. The provision of a floating outer leaf will preferably allow relative movement between the main frame and the folding frame wall in order to adjust for any height differential in the level of the floor. In the present application, the term ‘floating’ is intended to mean that the leaf will have vertical freedom to move, typically within outer limits, but movement of the hinge is preferably constrained in all other directions.

In an embodiment, the outer leaf may be provided in a slot opening in the first frame wall which is longer than the outer leaf, to provide a degree of movement vertically but also to confine the movement of the outer leaf. A second frame wall is preferably provided. In the preferred bifold configuration, an inner side of the second frame wall is typically mounted to an outer side of the first frame wall. The second frame wall is preferably mounted relative to the first frame wall using at least one hinge. Preferably two or more hinges are provided.

In an embodiment, at least one upper hinge and at least one lower hinge is provided between the second frame wall and the first frame wall. Each of the hinges is preferably a concealed hinge. Each of the hinges preferably has at least an inner leaf attached to the first frame wall and at least an outer leaf attached to the second frame wall. Each of the hinges preferably has at least an inner leaf attached to the first frame wall and at least an outer leaf attached to the second frame wall. At least one of the inner leaf and outer leaf is preferably fixed in position relative to the upright. At least one of the inner leaf and outer leaf may be provided in a floating configuration in which the inner leaf or outer leaf can move vertically, both up and down (within limits), relative to the other frame wall to adjust for any height differential in the level of the floor.

In an embodiment, the outer leaf may be provided in a slot opening in the second frame wall which is longer than the outer leaf in order to provide a degree of movement vertically but also to confine the movement of the outer leaf.

An outer end of the second frame wall is preferably mounted to the end wall frame. Preferably, the outer end of the second wall frame is mounted to the substantially vertical end members of the end wall frame. The second frame wall is preferably mounted relative to the end wall frame using at least one hinge. Preferably two or more hinges are provided.

In an embodiment, at least one upper hinge and at least one lower hinge is provided between the second frame wall and the end wall frame. Each of the hinges is preferably a concealed hinge. Each of the hinges preferably has at least an inner leaf attached to the second frame wall and at least an outer leaf attached to the end wall frame. Each of the hinges preferably has at least an inner leaf attached to the second frame wall and at least an outer leaf attached to the end support or end wall frame. At least one of the inner leaf and outer leaf may be provided is preferably fixed in position. At least one of the inner leaf and outer leaf may be provided in a floating configuration in which the inner leaf or outer leaf is mounted relative to but can move vertically, both up and down (within limits), relative to the second frame wall or the end support in order to adjust for any height differential in the level of the floor.

In an embodiment, the outer leaf of a floating configuration hinge may be provided in a slot opening in the end wall frame which is longer than the outer leaf, to provide a degree of movement vertically but also to confine the movement of the outer leaf.

Each of the frame walls is preferably configured as an open frame having a pair of substantially vertical members connected at the top end by a top rail and at the bottom end by a bottom rail (if the bottom rail is present). Each of the frame members is preferably elongate. Each of the frame members will preferably be manufactured from a light but strong and robust material such as a light metal. Although any cross-sectional shape may be used, it is preferred that the frame members are rectangular hollow section.

The movable floor structure, the movable roof structure, the roof of the main frame and/or the floor of the main frame may be formed in any way. One way is to provide a surround frame or surround members with a panel located relative to the surround frame but there are numerous other configurations that could be used such as a panel (without a surround frame) for example.

Corner bracing may be provided between the vertical members, the top rail and/or the bottom rail.

Preferably, the folding frame walls will unfold as the end wall frame is translated into the deployed position, and will fold as the end wall frame is translated into the storage position.

The pair of folding frame walls are preferably always substantially vertical.

Any one or more of the wall frames of the movable wall structure may be plumbed and/or wired through the wall frame so that only external connections are required once the movable wall structure has been deployed. Typically, the pair of folding frame walls will be located within the recess area when in the storage position. Preferably, the pair of folding frame walls will be located between the unswept area of the main frame on an inner side, and the end wall frame on the outside when in the storage condition. The provision of the movable wall structures within the recess portion of the main frame will preferably maintain the unswept area in the main frame. In a preferred configuration, a substantial portion of the volume of the main frame will be unswept by any of the moving components of the portable building structure.

In an embodiment, the portable building structure may be formed within a shipping container and deployed from within the shipping container, without removing the portable building structure from the shipping container. The provision of the portable building structure in this configuration may require adjustments to be made to a shipping container such as the removal of walls for example. Detailed Description of the Invention

In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 is an isometric view of a portable building structure according to an embodiment in the storage/transport condition.

Figure 2 is an isometric view of the portable building structure illustrated in Figure 1 in the expanded condition.

Figure 3 is an end view of the portable building structure illustrated in Figure 1.

Figure 4 is a schematic flow showing the expansion of the portable building structure illustrated in Figure 1 to the configuration illustrated in Figure 2

Figure 5 is an isometric view of the portable building structure illustrated in Figure 1 in a partially expanded condition. Figure 6 is an isometric partial view showing the location and detail of a lower roller on a movable wall frame according to an embodiment.

Figure 7 is an end view of the lower portion of the portable building structure illustrated in Figure 1 and detail of the floor assembly in the storage and deployed positions.

Figure 8 is an end view of the floor assembly of the portable building structure illustrated in Figure 1 in the folded and unfolded positions.

Figure 9 is an isometric view showing the location and detail of an upper roller on a movable wall frame according to an embodiment. Figure 10 is an end view of the upper portion of the portable building structure illustrated in Figure 1 and detail of the roof assembly.

Figure 11 is an end view of the roof assembly of the portable building structure illustrated in Figure 1 in the folded and unfolded positions.

Figure 12 is an isometric view showing the location and detail of a floating hinge arrangement according to an embodiment.

Figure 13 is an isometric view of a mounting hinge between the floor and the main body according to an embodiment in the storage position.

Figure 14 is an end view of the configuration illustrated in Figure 13 with the floor in the storage/transport condition. Figure 15 is an isometric view of the configuration illustrated in Figure 13 in the deployed position.

Figure 16 is an end view of the configuration illustrated in Figure 13 with the floor in the deployed condition.

Figure 17 is an isometric view of a mounting hinge between the roof and the main body in the storage/transport condition, according to an embodiment.

Figure 18 is an end view of the configuration illustrated in Figure 17 with the roof in the storage/transport condition. Figure 19 is an isometric view of the configuration illustrated in Figure 17 with the roof in the deployed condition.

Figure 20 is an end view of the configuration illustrated in Figure 17 with the roof in the deployed condition.

With reference to the accompanying figures, a portable building structure 10 is shown. The illustrated portable building structure 10 includes a central main frame 11 with a fixed roof 12, a fixed floor 13, and a pair of spaced apart uprights 14 located at each end of the main frame 11 between the fixed roof 12 and fixed floor 13. Each of the uprights 14 are spaced inwardly from a lateral edge of the fixed roof 12 and the fixed floor 13 to create a recess 15 at the top and bottom of the main frame 11, on each lateral side of the main frame 11.

The portable building structure 10 also includes a movable roof structure 16 mounted relative to the recess 15 on each lateral side of the main frame 11 for movement between a raised, use position illustrated in Figure 2 and a folded, storage position in which the movable roof structure 16 at least partially closes a lateral side of the main frame 11.

The portable building structure 10 also includes a movable floor structure 17 mounted relative to the recess 15 on each lateral side of the main frame 11 for movement between a lowered, use position, illustrated in Figure 2 and a folded, storage position in which the at least one movable floor structure at least partially closes the lateral side of the main frame, illustrated in Figure 1.

A moveable wall structure is provided on either lateral side of the main frame 11. The moveable wall structure includes an end wall frame 18, and a pair of bifold frame walls, one at each end of the main frame 11. An inner bifold 19 of each pair of frame walls is mounted relative to the recess 15 and an outer bifold 20 of each pair of frame walls is mounted to the end wall frame 18.

The pair of bifold frame walls mount the end wall frame 18 for sliding movement from a storage position within the recess 15, to a use position between an outer end of the movable roof structure 16 and movable floor structure 17 when deployed. The stages of deployment of the portable building structure 10 are illustrated in Figure 4.

The portable building structure of the present invention is typically transportable. The building structure will typically be transported in the storage configuration illustrated in Figure 1 and once on site, is expanded or deployed into the use configuration illustrated in Figure 2.

The unswept volume 21 in the main frame 11 of the building structure 10 provides a volume in which to store items within the structure 10, but the items can be stored in this volume, in such a way that they do not need to be moved during the deployment of the building structure 10 or during use in order to deploy the building structure 10.

As illustrated, all of the walls of the portable building structure 10 are provided as frame walls, formed from a number of frame members attached to or relative to one another. This allows a reduction in weight. It also allows the appearance of the building structure 10 to be changed by attaching different wall panels relative to the frame.

The building structure 10 illustrated is fitted with ISO corner castings 22 provided at each of the upper and lower, outer ends of the main frame 11. The number and positioning of the ISO corner castings 22 is such that standard handling equipment can be used to handle the portable building structure 10 when in the storage configuration.

As illustrated, the main frame 11 is constructed using a number of frame members attached together to form the main frame 11. The sides of the main frame 11 will typically be open, with the top of the main frame 11 closed by the fixed roof 12 and the bottom of the main frame 11 closed by the fixed floor 13.

The fixed roof 12 includes a single roof panel 22 provided within a surround frame made up of a number of frame members. The surround frame (and fixed roof) is generally rectangular as shown. The surround frame will normally be formed from a pair of spaced apart, substantially parallel side members 24 and a pair of spaced apart substantially parallel end members 25. A corner casting 22 is provided at each of the corners of the surround frame of the fixed roof 12. The side members 24 of the fixed roof surround frame are spaced inwardly, preferably evenly, from the lateral extremity of the main frame 11 by a distance of approximately ½ of the width of the comer castings 22. The roof panel 22 may be formed of any material but a metal is preferred.

The fixed floor 13 includes a single floor panel 26 provided relative to a surround frame. The surround frame (and fixed floor) is generally rectangular as shown. The surround frame will normally be formed from a pair of spaced apart, substantially parallel side members 27 and a pair of spaced apart substantially parallel end members 28. A corner casting 22 is provided at each of the comers of the surround frame of the fixed floor 13. The side members 27 of the fixed floor surround frame are located such that an outer wall of the side members 27 is positioned adjacent to the lateral extremity of the main frame 11 (extending to be approximately coplanar with the outside surface of the comer castings 22). The floor panel 26 may be formed of any material but a metal is preferred.

Each of the surround frames will typically be formed from a number of frame members which are attached together. Each of the frame members are elongate. Each of the frame members are preferably made of a robust and strong material usually a light metal. Although each of the frame members may have any cross-sectional shape, a rectangular hollow section (RHS) is preferred. Typically, the surround frame members are permanently attached to or relative to one another using an appropriate attachment method such as welding if the members are metal.

The fixed roof 12 and the fixed floor 13 are separated by a pair of spaced apart uprights 14 located at each end of the main frame 11 between the fixed floor 12 and the fixed roof 13. As shown, the pair of spaced apart uprights 14 are located between the end members 25, 28 of the surround frames of the fixed floor 13 and fixed roof 12. In the illustrated embodiment, both of the pair of spaced apart uprights 14 located at each end of the main frame 11 are spaced inwardly from the respective lateral edge of the main frame 11 to create a recess 15 on each lateral side of the main frame 11. The recess 15 extends over the length of the main frame 11, at the top and the bottom.

Each of the uprights 14 is preferably elongate. Each of the uprights 14 is preferably manufactured from a strong and robust material. A light metal is preferred. Each of the uprights 14 is a rectangular hollow section (RHS). Angled bracing plates 29 are provided between each of the uprights 14 and the respective end member 25, 28 of the surround frames of the fixed floor 13 and fixed roof 12. The angled plates 29 also function as gusset plates used to strengthen joints, but also to be used as attachment points for wall panels.

Together, the pairs of spaced apart uprights 14 located at each end of the main frame 11 define a generally rectangular area between them within the main frame 11, which is the unswept area. The unswept area of the illustrated embodiment extends over the height of the main frame 11 between the fixed floor 13 and the fixed roof 12. The other components of the portable building structure are preferably mounted relative to the main frame 11 outside the uprights 14, or at least no further inwardly than the inner side of the uprights 14. The recess 15 is defined between an outer side of the uprights 14 on one lateral side of the main frame 11 and the outer end of the end members 24, 27 of the fixed floor 13 and fixed roof 12.

As shown best in Figures 6 to 8, a guide channel 30 is provided on an upper side of each end member 28 of the surround frame of the fixed floor 13, in the recess area 15. The guide channel 30 extends laterally over the length of the recess 15 and the corner casting 22.

As shown best in Figures 6 to 8, a guide channel 31 is provided on a lower side of each end member 25 of the surround frame of the fixed roof 12, in the recess area 15. The guide channel 31 extends laterally to the outer side of the side member 24 of the surround frame, part way across the corner casting 22.

As will be explained further below, the guide channels 30, 31 guide movement of the end wall frame 18 of the movable wall structure.

The guide channels 30, 31 as illustrated are substantially U-shaped, having a pair of spaced apart, substantially parallel upstanding walls and a transverse linking web therebetween. As shown in Figures 7 and 10 in particular, the ends of the substantially parallel upstanding walls are arcuate in order to assist with clearance, when the movable roof structure 16 and movable floor structure 17 are moved.

The movable roof structure 16 of the illustrated embodiment includes a single roof panel 32 extending over the length of the portable building structure 11 and substantially the height of the main frame 11. Providing a single roof panel 32 of this size allows the height of the main frame 11 to define the maximum span of the roof (the span of the roof can be smaller than the height but not larger) but also to allow the roof panel 32 to at least partially close a lateral side of the main frame 11 when in the storage position.

In situations where a pair of movable roof structures 16 are provided, such as that illustrated, one on either lateral side of the main frame 11, this allows the deployed configuration of the portable building structure 10 to be up to 3 times the volume of the main frame 11 (of course depending upon the dimension of the main frame).

The movable roof structure 16 of the illustrated embodiment is formed of an outer surround frame provided about, and surrounding the roof panel 32. The outer surround frame illustrated includes a pair of spaced apart, substantially parallel side members and a pair of transversely extending, parallel, spaced apart end members rendering the surround frame substantially rectangular.

As shown in Figure 17, a shaped comer portion 33 is provided at the respective inner corners of the surround frame of the movable roof structure 16. The corner portion 33 shown is substantially L-shaped to allow clearance for the movable roof structure 16 about the comer casting 22. In the illustrated configuration, the inner side member of the surround frame of the movable roof structure is not full length, stopping short of the end members and the end members of the surround frame of the movable roof structure 16 are not full width, stopping short of the inner side member. The inner side member and the end members are typically connected using an L-shaped comer structure to provide the clearance for the comer casting 22.

The inner side member of the surround frame of the movable roof structure 16 is mounted to the side member 24 of the surround frame of the fixed roof 12 of the main frame 11 using an elongate hinge 34 extending over the length of the inner side member of the movable roof structure 16. The elongate hinge 34 preferably extends over the full length of the inner side member between the corner castings 22. In this embodiment, the hinge 34 is a piano hinge. As best illustrated in Figures 9 to 11, a guide channel 35 is provided on an under side (when deployed) or inner side (when stored) of each end member of the surround frame of the movable roof structure 16. The guide channel aligns with guide channel 31 to guide movement of the end wall frame 18 of the movable wall structure during deployment and storage. The channel 35 is substantially U-shaped, having a pair of spaced apart, substantially parallel upstanding walls and a transverse linking web therebetween. As shown in Figure 10 in particular, the ends of the substantially parallel walls of the channel 35 are spaced from the substantially parallel walls of the adjacent channel 31 located in the recess area 15 in order to provide clearance for movement of the movable roof structure 16. The ends of the substantially parallel walls of the channels 31, 35 are arcuate to enhance this clearance.

As best shown in Figures 17 to 20, the channel 35 extends across the open part of the shaped corner portion 33 provided at an inner side of the movable roof structure 16. When the movable roof structure 16 is in the deployed condition, the end portion of the channel 35 lies underneath the corner casting 22 as shown in Figures 19 and 20.

In the use position illustrated in Figure 2 at least, the movable roof structure 16 is substantially horizontal and preferably substantially coplanar with the fixed roof 12 of the main frame 11.

In the collapsed position, for storage and/or transport, as shown in Figure 1 at least, the movable roof structure 16 is preferably substantially vertical. In this position, the movable roof structure 16 will preferably at least partially close a lateral side of the main frame 11.

In the illustrated embodiment, a pair of lifting springs, pneumatic springs or gas struts 36 is provided, one at either end of the movable roof structure 16 to provide assistance to a user in moving the movable roof structure, 16 particularly into the use position. Normally, the lifting springs, pneumatic springs or gas struts 36 are provided between an upright 14 of the main frame 11 and an end frame member of the surround frame of the movable roof structure 16.

The lifting springs, pneumatic springs or gas struts 36 are removably attachable. In the illustrated embodiment, a stub axle or connector is provided on the frame members at either end of the lifting springs, pneumatic springs or gas struts 36 and the lifting springs, pneumatic springs or gas struts 36 are provided with a ball socket or similar arrangement at each end in order to be removably located relative to the stub axle or connector. The lifting springs, pneumatic springs or gas struts 36 are normally used to assist the movement of the movable roof structure 16 and then be removed whilst the building structure 11 is in use.

As shown in Figure 10 and 11, the movable roof structure 16 is mounted within the recess area 15 of the main frame 11. The movable roof structure 16 is preferably received within the recess area 15 between the fixed roof 12 and fixed floor 13 of the main frame 11, when in the storage or collapsed position.

As illustrated, the movable floor structure 17 include a single floor panel 38 extending over the length of the portable building structure 11 and the height of the main frame 11. Providing a single floor panel 38 of this size allows the height of the main frame 11 to define the maximum span of the floor (the span of the floor may be smaller than the height but not larger) but also to allow the floor panel 38 to at least partially close a lateral side of the main frame 11 when in the storage position. In an embodiment, the floor panel is substantially planar and manufactured of a light metal.

Typically, a movable floor structure 17 is provided on both lateral sides of the main frame 11, which allows the deployed configuration of the portable building structure 10 to be up to 3 times the volume of the main frame 11 (of course depending upon the dimension of the main frame).

As illustrated, the movable floor structure 17 is preferably substantially planar, formed of an outer surround frame provided about, and surrounding a floor panel 38. The outer surround frame preferably includes a pair of spaced apart, substantially parallel side members and a pair of transversely extending, parallel, spaced apart end members.

In the illustrated embodiment and in contrast to the inner side member of the surround frame of the movable roof 16, the inner side member of the surround frame of the movable floor structure 17 extends the full length of the movable floor structure 17 and main frame 11. As shown in Figures 6 to 8, the inner side member of the surround frame of the movable floor structure 17 is mounted to the side member 27 of the surround frame of the fixed floor 13 of the main frame 11 using an elongate hinge 39 extending over the length of the inner side member between the corner castings 22. In this embodiment, the hinge 39 is a piano hinge.

As shown in Figures 5 to 8, a guide channel 40 is preferably provided on an upper side (when deployed) or inner side (when stored) of each end member of the surround frame of the movable floor structure 17. As will be explained further below, the guide channel 40 will typically guide movement of the movable wall structure. The guide channel 40 will typically be substantially U-shaped, having a pair of spaced apart, substantially parallel upstanding walls and a transverse linking web therebetween. As shown in Figure 6 and 7, the guide channel 40 is preferably aligned with the guide channel 30 provided on the upper side of the lower end member 28 of the main frame 11 in the recess area 15. As seen best in Figure 7, the ends of the substantially parallel walls of the channel 40 are spaced from the substantially parallel walls of the adjacent channel 30 located in the recess area 15 in order to provide clearance for movement of the movable floor structure 17. The ends of the substantially parallel walls of the channel 30, 40 are preferably arcuate to enhance this clearance.

In the use position shown in Figure 2 at least, the movable floor structure 17 is preferably substantially horizontal and substantially coplanar with the fixed floor 13 of the main frame 11.

In the collapsed position shown in Figure 1 at least, for storage and/or transport, the movable floor structure 17 is preferably substantially vertical. In this position, the movable floor structure 17 will preferably at least partially close a lateral side of the main frame 11.

One or more lifting springs, pneumatic springs or gas strut assistance mechanisms are provided in the illustrated embodiment, provided in relation to the movable floor structure 17 to provide assistance to a user in moving the movable floor structure 17. As shown in Figure 5 at least, a pair of assistance mechanisms are provided between an upright 14 of the main frame 11 and an end frame member of the surround frame of the movable floor structure 17. The assistance mechanisms 41 are typically removably attachable. In an embodiment, a stub axle or connector may be provided on the frame members and the assistance mechanisms 41 are provided with a ball socket (or similar arrangement) at each end in order to be removably located relative to the stub axle or connector. The assistance mechanisms 41 may be used to assist the movement of the movable floor structure 17 and then be removed whilst the building structure 10 is in use.

In contrast with the movable roof structure 16, the movable floor structure 17 is typically mounted relative to the main frame 11 at an outer edge of the recess 15 at a lower side of the main frame 11 as shown in Figure 7 in particular. The movable floor structure 17 will preferably be located outside the recess 15 when in the folded or storage position. In addition, the movable floor structure 17 will typically lack the corner portions provided on the movable roof structure 33 shown in Figure 17, in order to provide clearance for the corner castings 22 if provided. The movable floor structure 17 will be located outside the movable roof structure 16 in the storage position and is normally deployed before the movable roof structure 16 when deploying the building structure 10 and will be moved after the movable roof structure 16 when moving the building structure 10 to the storage or transport condition.

As shown in Figure 5 in particular, the end wall frame 18 is mounted to an outer bifold 20 of each of the pair of folding frame walls. The end wall frame 18 moves between the movable roof structure 16 and movable floor structure 17, translating from the storage position to the use position once the movable roof structure 16 and movable floor structure 17 have been deployed. The end wall frame 18 can be moved by an operator, which causes movement of the pair of folding frame walls and/or the pair of folding frame walls can be moved, which causes movement of the end wall frame 18. The end wall frame 18 will remain substantially vertical at all times during use, during deployment between the use position and the storage position and back, and during storage.

As illustrated, the end wall frame 18 is formed from a pair of substantially vertical end members 44, a top rail 43 and an optional bottom rail 45. A pair of intermediate upright members 46 are provided between the substantially vertical end members 43. The members of the end wall frame 18 are preferably elongate. The members of the end wall frame are typically formed from a strong and robust material of which a light metal is preferred. Although the members may have any cross-sectional shape, preferably, each of the members is a rectangular hollow section.

The end wall frame 18 is typically relative to the movable roof structure 16 and the movable floor structure 17 using a roller 47 at a lower end of each of the substantially vertical end members 44 of the end wall frame 18 (as illustrated in Figure 6) and a roller 47 provided at an upper end of each of the substantially vertical end members 44 of the end wall frame 18 (as illustrated in Figure 9). Each roller 47 will typically travel in a respective guide channel 30, 31 provided on the main frame 11 (at the start of deployment and the end of the storage) and a guide channel 35, 40 on the side members of the surround frame of the movable roof structure 16 and movable floor structure 17.

In the illustrated embodiment, the end wall frame 18 is preferably load-bearing. When deployed, the end wall frame 18 will usually support the movable roof structure 16 above the movable floor structure 17 by abutment of the rollers in the guide channels 35, 40. Each of the rollers 47 (at least at the lower side) provided is also normally load- bearing.

As shown in Figure 3, the end wall frame 18 will normally be received within the recess area 15 when in the storage position. The end wall frame 18 is typically located inside the movable roof structure 16 when the portable building structure 10 is in the storage condition.

As mentioned previously, one or more wall panels can be mounted relative to the end wall frame 18 in order to partially enclose the building structure.

A folding frame wall is preferably provided at each end of the main frame 11. A folding frame wall is preferably provided between each end of the main frame 11 and the respective end of the end wall frame 18. Each folding frame wall is connected to the end wall frame 18 such that movement of the end wall frame 18 also moves each folding frame wall and vice versa. Each folding frame wall is preferably not supported directly by the movable roof structure 16 or the movable floor structure 17 but is supported relative to rollers 47 to allow movement. Each folding frame wall is typically supported between the end wall frame 18 and the upright 14 of the main frame 11.

As illustrated, each of the pair of folding frame walls includes two bifold frame walls which fold relative to one another, an inner bifold 19 mounted relative to the upright 14 and an outer bifold 20 mounted outside the inner bifold 19 and to the end wall frame 18.

The inner bifold 19 is preferably mounted relative to an outer side or surface of the upright 14. The inner bifold 19 is preferably mounted relative to the upright 14 using a number of hinges 48. Three hinges 48 are used in the illustrated embodiment.

The hinges 48 are provided between the inner bifold 19 and the upright 14. Each of the hinges 48 is preferably a concealed hinge. Each of the hinges preferably has an inner leaf attached to the upright 14 and an outer leaf attached to the inner bifold 19. Both leaves are preferably fixed in position relative to the upright 14.

An outer bifold 20 is preferably provided with an inner side of the outer bifold 20 typically mounted to an outer side of the inner bifold 19. The outer bifold 20 is preferably mounted relative to the inner bifold 19 using a number of hinges 49. Three hinges 49 are used in the illustrated embodiment.

Each of the hinges 49 is preferably a concealed hinge. Each of the hinges 49 preferably has an inner leaf attached to the inner bifold 19 and an outer leaf attached to the outer bifold 20. As shown in Figure 12, the inner leaf is preferably fixed in position relative to the inner bifold 19. The outer leaf is preferably provided in a floating configuration in which the outer leaf of hinge 49 between the inner bifold 19 and the outer bifold 20 so that the bifolds 19, 20 can move vertically, both up and down relative to one another. The provision of a floating outer leaf will allow relative movement (within limits) between the inner bifold 19 and the outer bifold 20 in order to adjust for any height differential in the level of the floor or ground upon which the building structure 10 is located.

In the embodiment shown in Figure 12, the outer leaf is provided in a slot opening 50 in the outer bifold 20 which is longer than the outer leaf of the hinge in order to provide a degree of movement vertically between the inner bifold 19 and the outer bifold 20 but also to confine the movement of the outer leaf.

As shown in numerous Figures, an outer end of the outer bifold 20 is mounted to the end wall frame 18. Preferably, the outer end of the outer bifold 20 is mounted to the substantially vertical end members 44 of the end wall frame 18. The outer bifold 20 is preferably mounted relative to the end wall frame 18 using a number of hinges 48. Three hinges 48 are used in the illustrated embodiment.

Each of the hinges 48 is preferably a concealed hinge. Each of the hinges preferably has an inner leaf attached to the outer bifold 20 and an outer leaf attached to the end wall frame 18. Both leaves are preferably fixed in position relative to the outer bifold 20 and the end wall frame 18.

As shown, each of the frame walls of the portable building structure 10 is preferably configured as an open frame having a pair of substantially vertical members connected at the top end by a top rail and at the bottom end by a bottom rail. Each of the frame members is preferably elongate. Each of the frame members will preferably be manufactured from a light but strong and robust material such as a light metal. Although any cross-sectional shape may be used, it is preferred that the frame members are rectangular hollow section.

Corner bracing may be provided between the vertical members, the top rail and/or the bottom rail and in the illustrated form, the corner bracing is an angled plate.

The inner bifold 19 and outer bifold 20 unfold as the end wall frame 18 is translated into the deployed position and fold as the end wall frame 18 is translated into the storage position. The folding frame walls are preferably always substantially vertical.

Any one or more of the wall frames of the movable wall structure may be plumbed and/or wired.

As shown in Figure 3 in particular, the inner bifold 19 and outer bifold 20 are located within the recess area 15 of the main frame 11 when in the storage position, located between the unswept area 21 of the main frame 11 on an inner side, and the end wall frame 18 on the outside. The one or more embodiments are described above by way of example only. Many variations are possible without departing from the scope of protection afforded by the appended claims.