Adjustable Structural Assembly and Method

Technical Field

The present invention relates generally to a structural assembly and has been developed especially, but not exclusively, for use in framing systems for prefabricated buildings and the like, and the invention is herein described in that context. However it is to be appreciated that the invention has broader application and is not limited to that particular use. In further aspects, the invention is also directed to methods of forming a structural assembly and to methods of using structural assemblies in a building environment.

Background

Under conventional techniques, buildings are constructed on site. Building materials are transported on site where they are cut in their required length or shape and assembled together. To improve the efficiency of construction, component parts (or whole buildings) may be prefabricated and delivered on site in a fully or partially assembled form. A significant advantage of prefabrication is that it provides a more controlled and often better equipped environment for manufacture which can lead not only to efficiencies in the manufacturing process but also increased quality.

However, there are still contingencies which need to be taken into consideration in prefabricating building components. For example, the required length of a structural element may vary due to manufacturing

tolerances, material thicknesses and the like. Accordingly, even though there may be a theoretical length for a particular member, there is still often a need to provide minor adjustment to element length. However, to take maximum advantage of a prefabrication process, it is beneficial if component lengths are manufactured to "standard" sizes to take improve operating efficiencies. Accordingly, there is a continuing need to more effectively cater for minor adjustments that may need to be made to these "standard "components.

Summary of Invention

In the first aspect, there is provided a structural assembly comprising first and second members, the members being nested one within the other and being arranged to telescope along an axis of the assembly on application of a predetermined threshold load applied along the axis.

In a particular form, the threshold load is greater than 1,000 Newtons and in a particular form is between 5,000 and 10,000 Newtons.

In accordance with a first aspect of the present invention, a structural assembly is provided where the length of the assembly can be adjusted by application of a threshold load. Typically this force is one which requires the use of pressing equipment and is beyond that which could be done manually.

The applicant has realised that a structural assembly according to the above form has significant advantage in the area of prefabricated construction for building frames

and the like where minor adjustment (say less than 20 millimetres) of the member length may be required. With the assembly of the present invention, the assembly forms a structural member (such as a beam or column element or the like) and is provided in a slightly oversized form and can be simply adjusted to its required length in a factory environment by being placed in an appropriate press. In this way, the structural assembly can be provided as a "standard" member and simply resized on site quickly and efficiently if required.

In accordance with a further aspect of the invention, there is a provided a method of forming a structural assembly of a required length, the method comprising steps of providing an adjustable assembly as defined above having a length along an axis greater than that required, and telescopically shortening the adjustable assembly along the axis to the required length.

In a particular form, the structural assembly comprises opposite ends disposed along the axis and wherein one end of each of the members forms respective ones of the ends of the assembly.

In a particular form, the end fittings are attached to at least one of the assembly ends .

In one form, each of the first and second members is formed as C-sections comprising first and second flanges, and a web interconnecting the first and second flanges. In a particular form, the first and second members are nested so as to form a closed section with the webs of the members being in opposing spaced relation and the first

and second flanges of the first member overlapping the other of the first and second flanges of the second member .

In one form, each flange has a return at a distal end thereof, and the web and the return of the first member interferes with the web and return of the second member to provide resistance to the predetermined threshold force.

In a particular form, the first flanges of the first and second members locate against an inner side of a second flange of the other of the first and second members .

As indicated above, in a preferred form, to telescope the members to provide axial shortening of the assembly requires a predetermined range of load to be applied. To be able to achieve this, it is necessary to control the dimensions of the respective members so that the frictional forces between the nested members are not too great or too low to prevent the telescoping of the members within that predetermined range.

In a particular form, the first flange of at least one of the members has formations which influence a dimension of that member which in turn allows some control over the threshold loading. In one form, in manufacturing of the member, a characteristic of that formation can be varied which in turn varies the dimensions of the first member. In a particular form, the formation has an adjustable depth wherein variation of the depth changes the length of the first flange. By having control of this dimension it is possible to control the frictional forces in the nested members to some extent .

In one form this formation is in the form an axial groove extending along the first flange .

In a further aspect, the invention is directed to a profiled member for use in a structural assembly according to any form described above .

In one form, the formation (with its characteristics that may be varied) is set following testing of samples of the structural assembly to ensure that the predetermined threshold force required to telescope the members is within the predetermined range. In one form this is achieved by taking samples from the manufacturing line (typically a cold roll forming line) ; nesting the two members together and then testing the load required to cause telescoping of the nested members. If the force required is too great, then the dimension of the first flange is reduced (typically by increasing the depth of the formation) . If the threshold force is too low, then the dimension of the first flange is increased by reducing the depth of the formation.

In a further aspect the invention is directed to a profiled member for use in a structural assembly according to any form described above.

In a further aspect the invention is directed to a profiled member extending in an axial direction between opposite ends thereof, the member being formed as a C section having first and second flanges, a web interconnecting the first and second flanges, and an axial groove extending along the first flange.

— o ^**■

In yet a further aspect, the invention provides a method of making an adjustable assembly formed from first and second members that are disposed in a nested arrangement, at least one of the members having a formation that influences a dimension of that member, the method comprising the steps of: establishing a required configuration of the formation of the at least one member so that when the first and second members are nested together the members are able to telescope along an axis of the assembly on application of a threshold load within a predetermined range along the axis; forming the first and second members with the required configuration of the formation; and nesting the first and second members, which either are in a preform state or a final state, one within the other to form the structural assembly.

In a further aspect, the invention is directed to a method of making an adjustable assembly, the method comprising the steps of: forming first and second preform members, each preform member having a first and a second flange and a web interconnecting the first and second flanges; nesting the first and second preform members one within the other to form a closed section with the webs of the members being in opposed spaced relationship, and the first flange of each member locating against an inner side of the second flange so that the first and second flanges overlap, and folding the distal end margins of the second flange of each of the first and second preform members over to form a return in contact with the web of the second and first members respectively to form the adjustable assembly.

In one form, the method further comprises the steps of establishing a required configuration of a formation in the first flange of the first and second members, each formation influencing the length of the respective flange in which it is located so that in the first and second members of the structural assembly are able to telescope along an axis of the assembly on application of a predetermined threshold load along the axis, and forming the first and second preform members with the required configuration of the formation.

Brief Description of the Drawings

It is convenient to herein after described an embodiment of the present invention with reference to the accompanying drawings. It is to be appreciated that the particularity of the drawings and the related description is to be understood as not superseding the generality of the preceding broad description of the invention.

In the drawings :

Fig. IA is a side view of a structural assembly according to an embodiment of the invention;

Fig. IB is a plan view of the assembly of Fig. IA; Fig. 2 is a detailed view of an end connection for the assembly of Fig. IA;

Fig. 3 is an end view of the assembly of Fig. IA;

Fig. 4 is an end view of a member which forms a component of the assembly of Fig. IA. Fig.5 is an end view of the member of Fig.4 in a preform state; and

Fig.6 is an end view of the assembly of Fig. IA showing the members in a preform state in phantom.

As illustrated in Figs. IA to 3 , a structural assembly 10 is disclosed which is formed from first and second channel members 11, 12 which are nested so as to form a hollow section. Each of the members 11,12 are identical and as best illustrated in Fig. 4 include a web 13 that incorporates longitudinal upper and lower grooves 14 and 15, a first flange 16, a second flange 17 and respective distal returns 18 and 19. A characteristic feature of the members 11,12 is that the first flange 16 incorporates a longitudinal groove 20. As will be explained in more detail below the depth of the groove 20 may be controlled during manufacture of the members 11, 12 so as to provide some control over the length of the flange 16.

Turning back to Figs. IA and IB, the assembly 10 is formed by nesting of the channel members 11,12 so as to form a box section. Whilst these members 11,12 are of identical length, they are nested in an arrangement wherein they are slightly offset (X) from one another along an axis A of the structural assembly. With this arrangement, one end 21 of the assembly 10 is formed by an end 22 of the first member 11 whereas the other end 23 of the structural assembly 10 is formed by an end 24 of the second structural member 12. In the illustrated embodiment this offset (X) of the first and second members 11,12 is relatively minor and is typically less than 50 mm. However it is to be appreciated that the overlap could vary depending on the requirements of the application in which the assembly 10 is used.

The assembly 10 further incorporates notches 25,26 at the respective ends 21 and 23 of the assembly 10. The

assembly 10 in the illustrated form is used as a beam in a prefabricated building and the notches 25 and 26 are provided to accommodate a steel wall system projecting upwardly from the respective ends of the beams. Furthermore in the illustrated form, end plates 27 are arranged to be secured to the ends 21 and 23 by mechanical fasteners 28 through gusset plates 29 located internally within the hollow section.

The structural assembly 10 is provided with the offset channel members 11 and 12 so that in use the members can be telescoped one within the other to reduce the overall length of the assembly 10. The maximum amount of reduction in length is equal to the amount of offset. In use the length of the structural assembly may vary but is typically in the order of 2 and 3 metres. In view of the frictional forces between the nested members 11 and 12 any telescopic adjustment of the assembly to reduce the length of that assembly is not done manually but is required to be done using a pressing equipment with the force typically in the order of 5,000 to 10,000 Newtons .

As best seen in Fig. 3, the channelled members 11 and 12 are nested together so that the respective webs 13 of the channel members are in opposing relationship and the first flanges 16 locate within the second flanges 17. Furthermore the return 19 of the second flange 17 locates over a portion of the web 13 of the other channel member with its terminal end locating within the longitudinal groove 14 to nest the two channel members 11 and 12. In manufacturing of the assembly 10, the members 11, 12 are provided in a partially constructed form to allow for ease of nesting. This "preform" version of the members 11 and

12 is illustrated in Fig. 5 and the nesting of the members is described below with reference to Fig. 6. For convenience, the members 11, 12 in their preform state are given the same reference numerals in the drawings but with the superscript (1) for ease of identification.

As shown in Fig. 5 the preform members II ¹ , and 12 ¹ have the same general configuration and features of the members 11 and 12, with the exception that the return 19 ¹ is more open (i.e. formed at an obtuse angle to flange 17 ¹ ) . The member II ¹ and 12 ¹ are able to be nested together in this state as the return 19 ¹ does not prevent lateral insertion of flange 16 ¹ of the other member. Once these preforms II ¹ and 12 ¹ are nested together, they are then clamped in place by closing of the returns 19 ¹ which locks in the individual web recesses 14 and thereby place the members 11 and 12 in there final configuration.

To control the frictional forces generated at the interlocking members (which in turn determines the required forces to telescope the members) the members 11 and 12 are formed, typically by a roll forming process, with the flange groove 20. By intermittent testing of the nested channel members to assess the amount of force required to telescope those members it is possible to set a depth of the groove 20 to a desired depth. If the force required is too great, the depth of the formation is increased which thereby reduces the overall dimension of the first flange. If the threshold force is too low, then the dimension of the first flange is increased by reducing the depth of the formation.

The structural assembly 10 is ideally suited for prefabricated construction. In that application, the

assembly 10 can be provided as a "standard item" and is provided in a slightly oversized form. Once on site, the required length of the member can be established, either by direct measurement or by calculation taking into account contingency factors such as material thickness and the like. Once the required length is established, the structural assembly 10 can be simply resized on site quickly and efficiently by being placed in a press to allow the minor adjustment in length due to telescoping of the two members .

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as

"comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Variations and modifications may be made to the parts previously described without departing from the ambit of the invention as defined by the accompanying claims.