WO2019071300A1

WO2019071300A1 - Formwork system

Info

Publication number: WO2019071300A1
Application number: PCT/AU2018/051086
Authority: WO
Inventors: Stephen W DARWELL
Original assignee: Csr Building Products Limited
Priority date: 2017-10-10
Filing date: 2018-10-09
Publication date: 2019-04-18
Also published as: AU2024201276A1; AU2018247206A1

Abstract

Disclosed is a building formwork system (100) including a building formwork component (102), building formwork connector (204) and building formwork cap (306). In one arrangement, the building formwork system (100) can comprise a number of inter-connected building formwork components (e.g. 102a, 102b, 102c) that define a column, a building formwork connector (204) connecting two of the building formwork components (e.g. 102a, 102b) in the column, and two building formwork caps (306a, 306b) that are connected at two opposite sides of the column.

Description

Formwork System Technical Field

This disclosure relates to a building formwork system including a building formwork component, building formwork connector and building formwork cap.

Background Art

Formwork is used in the construction of buildings and other structures to provide a temporary or permanent mould into which concrete or other similar materials may be poured. Stay-in-place (or lost) formwork that comprises a number of components, some of which can be formed of plastic, is also known in the art.

It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.

Summary

Disclosed herein is a building formwork system. The building formwork system comprises a building formwork component and a cap for the component. The system can provide formwork that to be used to construct columns, pillars, pedestals, plinths and the like (e.g. the building formwork component can be capped at one or both sides/ends thereof). The building formwork component may be applied as stay-in-place (or lost) formwork.

The building formwork component of the system comprises walls that define a cavity for receipt of a cementitious material therein. The building formwork component also comprises first and second corresponding engagement portions. The cap of the system is configured to be retained by the first and second corresponding engagement portions of the component. The cap is further configured such that, in use, it is able to resist deflection intermediate the first and second corresponding engagement portions of the component. The ability of the cap to resist deflection enables the cap to better resist disconnection from the building formwork component due to bowing, blowout, etc. such as may arise from the hydraulic pressure applied to the cap when the component receives a cementitious material therein (e.g. it enables the cap to maintain a secure connection to the component as concrete is poured therein).

This prevention of bowing, blowout (or other failures of the cap) may be especially required in circumstances where a significant volume of cementitious material is to be received in the building formwork component (e.g. the component is completely filled with cementitious material). One such circumstance may, for example, be where a load- bearing structure (such as a column, wall, etc.) is being formed using the building formwork component together with the cap.

In an embodiment, each corresponding engagement portion may be arranged at a respective sidewall of the building formwork component. The sidewalls together with their corresponding engagement portions can define a space therebetween. The cap may be further configured to locate in this space so as to extend between and be retained by the first and second corresponding engagement portions of the component. In this way, the cap can seal the end of the building formwork component to contain the cementitious material therein.

When the building formwork component is viewed in profile, such a space can be seen to be located at one end of the component. The filling of such a space with the cap may further increase the rigidity of the overall formwork structure. In an embodiment, the building formwork component typically comprises at least one web extending between its sidewalls. The at least one web can further define the space in which the cap is to locate (i.e. the space can be bounded by the sidewalls, corresponding engagement portions and web). Typically, the component comprises at least two spaced webs extending between the sidewalls.

In an embodiment, each corresponding engagement portion may comprise a flange. Each flange may be disposed at a respective end of a sidewall of the building formwork component. In use, when the cap is located in the space, the cap can be retained therein by the flanges.

In an embodiment, each flange may be turned inwardly from, so as to form a right angle or an acute angle with, its respective sidewall. The inward turning of the flanges can help to better retain the cap in the space.

In an embodiment, the cap may be configured to substantially fill the space defined between the sidewalls, flanges and web of the component (e.g. the cap can locate therein in a snug-, friction-, tight- or interference- fit).

In an embodiment, the cap may be configured for being slid into engagement with the first and second corresponding engagement portions of the building formwork component.

In another embodiment, the cap may be configured for being snap-fit into engagement with the first and second corresponding engagement portions of the building formwork component.

In an embodiment, the cap may be defined by conventional building material - e.g. a building material that is capable of resisting deflection when located at the first and second corresponding engagement portions of the building formwork component. In an embodiment, the building material may comprise a slab, sheet or panel of the material.

In an embodiment, the building material may comprise fibre cement such as compressed fibre cement. Alternatively, the building material may comprise autoclaved aerated concrete (AAC); reinforced (e.g. fibre- reinforced) plasterboard, etc. Making use of such conventional building materials can provide a cost-effective and simple way of forming the cap. Such building materials are also able to resist deflection in use.

In an embodiment, the building material may be retained in the space between each flange and the at least one web (e.g. it may be held captive by the inwardly turned flanges).

In an embodiment the building formwork component may be of a moulded (e.g. extruded) plastic material.

In an alternative embodiment, the cap may be formed from a plastic material (e.g. by plastic moulding such as extrusion). For example, to enable it to be formed from plastic, the cap may comprise an outer skin and an internal reinforcement structure. Together with the outer skin, the internal reinforcement structure can function to resist deflection in use (e.g. from the hydraulic pressure applied thereto in use by the

cementitious material).

In this regard, the internal reinforcement structure of the cap may provide rigidity to the cap, which may prevent bowing of the cap in use when under load from e.g. the cementitious material that has been poured into the building formwork component. The plastic cap can be moulded to also comprise first and second engagement portions. Each of the cap engagement portions may engage with the corresponding engagement portions of the building formwork component. The interaction of the cap engagement portions with the corresponding engagement portions of the building formwork component can help to retain the cap connected to the component, typically in a secure manner, whereby the cap resists disconnection in use. The cap can further comprise a cap portion that extends between the first and second engagement portions. The cap portion can represent that part of the cap that is configured to resist deflection intermediate the first and second engagement portions. For example, the cap portion may comprise the outer skin and internal reinforcement structure as set forth above. When the cap is viewed in profile (e.g. from a top or bottom end thereof), the first and second engagement portions of the cap may be defined at respective first and second opposite ends of the cap portion (e.g. at end edges thereof).

For example, the cap may generally be defined as an elongate section, wherein each of the first and second engagement portions of the cap may extend for the length of the elongate section (i.e. the engagement portions may extend longitudinally along respective first and second longitudinal sides of the elongate section). The cap portion may define a wall of the elongate section. Thus, when the elongate section is viewed in profile, it can be seen that the first and second engagement portions may be located at the first and second opposite ends of the wall defined by the cap portion.

As set forth above, the cap may be configured to engage with the first and second corresponding engagement portions of the building formwork component. When the corresponding engagement portions are disposed at the ends of respective spaced sidewalls of the building formwork component, and when the cap is engaged to the building formwork component, the cap portion is able to span a gap defined between the spaced sidewalls.

In one embodiment the first and second cap engagement portions may be configured for slideable engagement with the first and second

corresponding engagement portions of the building formwork component. The configuring of the cap engagement portions for slideable engagement can provide for a stronger type of engagement between the cap and the building formwork component (e.g. the engagement portions of the cap and component can be designed to robustly interlock). This can provide a relatively rigid connection between the cap and the building formwork component (i.e. so as to better resist disconnection due to bowing, blowout, etc.).

Alternatively or additionally, the first and second cap engagement portions may be configured for snap engagement with the first and second corresponding engagement portions of the building formwork component. This can allow the cap to be engaged with the building formwork component by way of lateral movement (e.g. the cap may be pressed or pushed so as to snap onto the component). For example, where one or both of the cap and building formwork component have a substantial length, the lateral movement of the cap to snap onto the component can avoid the need to position one e.g. above the other in order to slide them together. However, the resultant interlock between the cap and component may not be as robust as the slide-together configuration.

In one embodiment the first and second cap engagement portions may each comprise a longitudinal groove. Each groove may be configured for receipt of a flange of a first or second corresponding engagement portion of the building formwork component. In another embodiment, the first and second cap engagement portions may instead comprise flanges for receipt in corresponding grooves of the building formwork component. In a further embodiment, one of the cap engagement portions may comprise a flange, and the other of the cap engagement portions may comprise a groove, and these may respectively be received in or may receive a corresponding groove and a corresponding flange of the building formwork component. In one embodiment the outer skin of the cap may comprise two spaced walls. When the cap is viewed in profile, the two spaced walls may comprise long walls that extend between opposing end walls of the cap (i.e. the spaced walls may generally extend between the first and second edges of the cap portion). The spaced walls may be parallel. The spaced walls may be planar, or may be arcuate, or may have other suitable profiles. For example, an outer wall of the two walls (e.g. when the cap is engaged with the component) may have an arcuate profile, whilst an inner wall of the two walls may have a linear profile.

In one embodiment the internal reinforcement structure may comprise a plurality of webs extending between the spaced walls of the outer skin. The webs can function to strengthen the cap, whilst maintaining a substantially hollow, lighter-weight cap.

In one embodiment, at least some of the plurality of webs may extend generally perpendicularly to the spaced walls of the outer skin. In this or another embodiment, at least some of the plurality of webs may extend diagonally between the spaced walls of the outer skin. Thus, the internal reinforcement structure may comprise a combination of perpendicular and diagonal webs.

For example, in one embodiment the internal reinforcement structure, together with the two spaced walls of the outer skin, may define a truss. A truss is typically a particularly strong and/or rigid yet lightweight structure, which can help to reduce or prevent bowing, etc. of the cap in use. In one embodiment the cap may be of a unitary structure. This can increase the strength of the cap. This can also mean that the cap does not require any separate assembly.

In one embodiment the cap may be formed of a plastic such as PVC. Likewise, the building formwork component may be formed of a plastic such as PVC. When each is formed of plastic, each of the cap and component may be moulded - e.g. extruded. This can provide a cost- effective way of forming each of the cap and component.

Also disclosed herein is a building formwork connector. The connector can be used to connect two (e.g. like) building formwork components, each of which may be as set forth above. For example, each component can be of a type that comprises walls that define a cavity for receipt of a

cementitious material therein.

The connector can be used to connect the two building formwork components in a "back-to-back" arrangement (e.g. to reverse the orientation of adjacent components). Thus, once the two components are so connected, an end of one of the two components can be connected to a cap (such as set forth above), and an end of the other of the two components can be connected to another such cap, or the end may be connected to another (e.g. like) building formwork component. In this way, a column, wall, etc. can be constructed that can be "capped" at each end.

In an embodiment, when the connector is viewed in end profile, it can be seen to comprise a web that extends between two flanges. Each flange may comprise first and second longitudinally extending edges. Each edge may be turned inwardly to define first and second lips. The flanges may be connected to a respective end of the web at respective intermediate flange locations (i.e. between their respective first and second lips). Typically, the connector is elongate. Further, the connector may generally be l-shaped in end profile. In this regard, the connector may be considered to be a type of "I-beam", with the web defining a stem of the Ί" and the flanges respectively defining the top and bottom of the Ί". In an embodiment, each pair of first lips and each pair of second lips of the connector may be configured for slideable engagement with a

corresponding pair of grooves formed in a respective building formwork component (the grooves may be arranged as set forth above).

Alternatively or additionally, each pair of first lips and each pair of second lips of the connector may be configured for snap engagement with a corresponding pair of grooves formed in a respective building formwork component (the grooves may be arranged as set forth above).

In an embodiment, when the connector is viewed in end profile, an outer surface of each lip may define either generally a right angle (e.g. for a slide-together setup), or a generally acute angle (e.g. for a slide- or snap- together setup), with respect to a remainder of the flange.

Also disclosed herein is a building formwork system that can comprise a connector as set forth above. The building formwork system can also comprise at least one building formwork component (e.g. as set forth above) that comprises walls that define a cavity for receipt of a

cementitious material therein. The at least one building formwork component can further comprise first and second corresponding engagement portions. Each corresponding engagement portion can be arranged for engaging with a respective pair of first lips or second lips of the connector.

Also disclosed herein is a building formwork system comprising a building formwork component (e.g. as set forth above). The walls of the component can define a cavity for receipt of cementitious material therein. A first engagement portion of the component can be configured according to a first connector type. A second engagement portion of the component can be configured according to a second connector type. The system can further comprise a building formwork connector (e.g. as set forth above). The connector can comprise first and second sides. Each of the first and second sides of the connector can be configured according to the first connector type. In the system, the first connector type and second connector type are configured for engagement with one another (e.g. via one or both of slideable engagement or snap engagement). The first connector type may, for example, be a male connector. The second connector type may, for example, be a female connector.

However, it should be appreciated that other connector types are envisaged, such as where one connector engages with another (i.e. of a different form), and such as where each connector comprises a hooking arrangement.

As set forth above, the connector can allow the orientation of a building formwork component to be reversed in a system that comprises multiple building formwork components. This can increase the versatility of the system, and may allow a larger number of arrangements to be formed with only the addition of the building formwork connector. It can also allow for opposing ends of a column or wall to be capped, as set forth above.

In one embodiment of the system, the building formwork component may comprise first and second ends. The first end may comprise the first engagement portion configured to the first connector type. The second end may comprise the second engagement portion configured to the second connector type. This can allow for (e.g. like) building formwork components to be joined end-to-end. It can also allow for the second ends of adjacent components to be joined to the connector. In one embodiment the system may further comprise a building formwork cap as set forth above. In this regard, the first and second engagement portions of the building formwork cap may be configured according to the second connector type. The use of a building formwork connector in the system may allow for two building formwork caps of the same type to be used at opposite ends of e.g. a structure formed using the building formwork components.

In other words, where the building formwork caps are only able to engage with the flange end of a building formwork component, the building formwork connector may allow the reversal of a building formwork component so that the flange end (that would otherwise be connected to an adjacent formwork component) becomes free for engagement with the building formwork cap. This can allow the formwork to be used to construct columns, pillars, pedestals, plinths and the like (i.e. capped at either side/end thereof).

Brief Description of the Drawings

Embodiments will now be described by way of example only, with reference to the accompanying drawings in which:

Figure 1A is a top end (profile) view of a building formwork system, in the form of a column; and

Figure 1 B is a perspective view of the building formwork system of Figure 1A; and

Figure 2 is an isometric detailed view of an upper portion of a connector of the building formwork system; and Figure 3 is a top end (profile) view of a building formwork cap; and

Figure 4A is a top end (profile) view of a building formwork component for use in e.g. the system of Figure 1 A; and Figure 4B is a top end (profile) view of the building formwork component of Figure 4A, but with another cap type connected thereto; and

Figure 5 is an end view of an upper portion of the building formwork component of Figure 4A; and

Figure 6 is a perspective view of the building formwork component of Figure 4A.

Detailed Description

In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure.

Figures 1A & 1 B show a building formwork system, which takes the form of a column 100. The building formwork system can, alternatively, take the form of a wall, plinth, pillar, pedestal, etc.

The building formwork system 100 comprises at least one building formwork component 102 (see also Figure 4A) and, in this embodiment, comprises three building formwork components 102a, 102b, 102c. The building formwork system 100 also comprises a building formwork connector 204 (see also Figure 2). The connector 204 connects together two of the building formwork components 102a, 102b. The building formwork system 100 further comprises at least one building formwork cap 306 (see also Figure 3) and, in this embodiment, comprises two building formwork caps 306a, 306b. The caps 306a, 306b are connected at opposite sides of the column 100. Each of these components of the system is described in more detail below. The three components 102a, 102b, 102c are generally identical with one another (i.e. each typically has the form as shown in Figure 4A). Each building formwork component 102a, 102b, 102c comprises two spaced parallel (and generally co-extensive) sidewalls 108. Three webs 1 10a, 110b, 110c extend between these sidewalls 108. A first web 1 10a extends across a first end of the sidewalls 108, a second web 110b extends across an opposite (second) end of the sidewalls 108, and a third web 110c extends between the sidewalls 108 intermediate the first 110a and second 110b webs. Although three webs 110a, 110b, 110c are shown in each building formwork component 102a, 102b, 102c of the illustrated embodiment, it should be appreciated that each building formwork component may have more (e.g. 4, 5, 6) or less (e.g. 1 , 2) webs.

As best shown in Figures 5 & 6, each of the webs 110 includes a plurality of generally rectangular apertures 113 that allow a cementitious material to flow across the webs 110. The apertures 1 13 also allow for the receipt of reinforcement bars in and extending through the components 102a, 102b, 102c. As is apparent from the Figures, the webs 110a, 110b, 110c are integral with the sidewalls 108. In the presently described

embodiment, the components 102a, 102b, 102c are each moulded (e.g. extruded from plastic) so as to provide the component with an integral (or unitary) structure.

At their respective first ends, the sidewalls 108 of each component 102a, 102b, 102c comprise a longitudinal groove 112 formed therein. At their respective second ends, the sidewalls 108 each comprise an inwardly projecting and longitudinally extending flange 114. The grooves 1 12 and flanges 114 are formed so as to be complementary. The flanges 1 14 extend inwardly and on an incline to their respective sidewalls 108 such that an outer surface of each flange 1 14 forms a sloped or inclined surface 115 (that forms an acute angle with the respective sidewall 108 - see Fig. 4A). In use, and as should be apparent from the figures, the flanges 114 of one component 102a, 102b, 102c can be received in the grooves 1 12 of another component 102a, 102b, 102c in order to secure the components 102a, 102b, 102c together. Due to their complementary shape, the flanges 114 closely or snugly fit within their respective grooves 112 so as to minimise movement between the components 102a, 102b, 102c once engaged.

The engagement of the flanges 114 and the grooves 1 12 can be performed in two ways. Firstly, one component 102a, 102b, 102c can be positioned above the other, and can then be moved along the longitudinal axis of the components 102a, 102b, 102c so as to slide the flanges 114 into the grooves 1 12 (i.e. so as to slideably engage the components 102a, 102b, 102c).

Alternatively, the components 102a, 102b, 102c may be snap-engaged by moving one of the components 102a, 102b, 102c towards another component in a lateral direction. In this case, the sloped surfaces of the flanges 114 of one building formwork component 102a, 102b, 102c contact an end of another building formwork component 102a, 102b, 102c, which causes the flanges 114 (and adjacent portions of the sidewalls 108) to move outwardly, due to the sloped (i.e. ramp) surfaces 1 15 on the flanges 114. As the building components 102a, 102b, 102c are moved further towards one another, the flanges 114 of one building component 102a, 102b, 102c 'snap' into the grooves 112 of the other building component 102a, 102b, 102c so as to be engaged with one another. A building formwork cap 306 is shown in more detail in Figure 3, which shows the cap from the top end (i.e. in profile). This cap 306 is identical to those shown in Figures 1 A and 1 B. The cap 306 comprises a cap portion 316 and first 318a and second 318b engagement portions. Like the components 102a, 102b, 102c, the cap 306 is a unitary structure that may be moulded (such as by extrusion - e.g. extruded from PVC). The engagement portions 318a, 318b comprise grooves 320 of a similar form to those present in the components 102a, 102b, 102c (described above). In this respect, the grooves 320 are configured for receipt of the flanges 114 of the components 102a, 102b, 102c, either by way of snap engagement or by way of sliding engagement as described above. This is apparent from Figures 1A and 1 B in which caps 306a, 306b are shown engaged with the flanges 1 14 of two of the components 102a, 102c.

The cap portion 316 generally extends between the first 318a and second 318b engagement portions and comprises an outer skin 322 and an internal reinforcement structure. 324. The outer skin 322 comprises two generally parallel spaced walls 326. The internal reinforcement structure 324 comprises a plurality of webs 328, 330. A first set of the webs 328 extend generally perpendicular to, and between, the sidewalls 326. A second set of the webs 330 extend diagonally between the sidewalls 326, and between the ends of the perpendicular webs 328 in an alternating manner (i.e. so as to form a zig-zag pattern). In this way, recesses having generally triangular profiles are defined between the sidewalls 326, perpendicular webs 328, and diagonal webs 330. In effect, the

combination of the sidewalls 326 and webs 328, 330 forms a truss that provides rigidity or stiffness to the cap 306 in use.

Figures 1 A and 1 B show two caps 306a, 306b engaged (by sliding or snap engagement) with respective ends of two components 102a, 102c, such that the cap portion 116 of each cap 306a, 306b extends across the end of the respective component 102a, 102c between the sidewalls 108 (i.e. so as to cap the components 102a, 102c). The ability to snap or slideably engage the cap 306a, 306b simplifies its use in the building formwork system 100, and minimises the tools and hardware required to install the cap 306a, 306b. When engaged in this way, an outer sidewall 126 of the cap portion 1 16 provides an end surface for the assembled formwork system 100. End walls of each cap 306a, 306b are generally flush with the outer surfaces of the sidewalls 108 of the components 102a, 102c, so as to create a generally continuous surface (i.e. a rectangular column). In this way, the outer surface of the building formwork system 100 may be suitable for use without applying a further finishing surface.

As should be apparent from the figures, the caps 306a, 306b are generally symmetrical about a lateral axis. This means that the caps 306a, 306b can be slideably engaged with respective components 102a, 102c in two orientations (i.e. the caps 306a, 306b can be slideably engaged when 'upside down'). In practice, this facilitates faster construction using the system 100.

Referring now to Figure 4B, an alternative cap 350 is shown. The cap 350 is formed from a conventional building or construction material such as a slab, sheet or panel of this material. The material that is selected for cap 350 is capable of resisting deflection (e.g. from the hydraulic pressure applied to the cap 350 in use by a cementitious material (e.g. concrete) poured into the adjacent component 102). The slab, sheet or panel for the cap 350 is sized such that it is able to be closely or snugly located between the sidewalls 108 adjacent to the flanges 1 14. As can be seen in Figure 4B, the cap 350 sits behind the sloped surfaces 1 15 of the flanges 114 and is retained captive thereby. The material for the cap 350 can comprise one of: compressed fibre cement, autoclaved aerated concrete (AAC), reinforced (e.g. fibre-reinforced) plasterboard, or other like, suitable building materials. Such a material can provide a simple and cost-effective way of forming and supplying the cap. A building formwork connector 204 is shown in more detail in Figure 2. The connector 204 comprises a central web 232 and two generally parallel and opposing flanges 234. Again, the connector 204 is elongate and integrally formed, and may be moulded (e.g. extruded) from plastic (such as PVC). The web 232 is generally planar and elongate and, like the webs 110 of the building components, includes a plurality of apertures 233 formed therein. The web 232 also comprises two longitudinal edges 236, with each of the two flanges 234 being connected to a respective longitudinal edge 236 of the web 232. In particular, each flange 234 is connected to the web longitudinal edge 236 at a central portion of the flange 234 (i.e. at an intermediate location along its length). This gives the connector 204 a generally T shaped profile (i.e. the connector 204 is a form of I-beam). Each edge 236 of the flanges is turned inwardly so as to define a lip 238. Each of these lips 238 has the same form as a flange 114 of the building formwork components 102a, 102b, 102c.

In this way, and as shown in Figures 1A and 1 B, the connector 204 can be connected, on a first side, to a building formwork component 102a by way of locating its inwardly extending first side lips 138 in the grooves 1 12 of the component 102a. The connector 204 can also be connected to a further building formwork component 102b, on a second side, by engagement of its second side lips 138 with the grooves 112 of the further component 102b. Again, this connection may be by way of a slideable or snap-engagement.

In practice, the building formwork connector 204 allows a user to use one type (i.e. having a particular connection type) of building formwork component 102 in an assembly. In other words, the connector 204 allows the reversal of the orientation of a building formwork component 102. This also means that the same cap type 306a, 306b can be used at each end of the assembly. In this case, the cap 306a, 306b has a female-type (i.e. groove) connection and the connector 204 has a male type (i.e. flange) connection. As should be apparent to the skilled person, this arrangement can be reversed and the same outcome can be achieved. Also, as should be apparent to the skilled person, the cap 306 or 350 can be connected to a given first or second side of connector 204. In the presently illustrated embodiments, the building formwork

components 102a, 102b, 102c, building formwork caps 306a, 306b, 350 and building formwork connector 204 have been arranged and engaged with one another in order to provide formwork for a column structure. Once the components of the system 100 are engaged with one another (as shown in the figures), a cementitious material, such as concrete, can be received in the assembly to form a column. It should be apparent, however that the system 100 can be used to form other structures, such as walls, plinths, pylons, pillars, pedestals, etc.

Because significant quantities of concrete can be required for the construction of columns (or other load bearing structures), a large amount of hydraulic pressure can be applied to various sidewalls of the building formwork system 100. The reinforcement/reinforced structure of the caps 306a, 306b, 350 ensures that any bowing (i.e. due to hydraulic pressures) of the caps 306a, 306b, 350 is minimal. In the illustrated embodiments, there is no gap present between the caps 306a, 306b, 350 and the webs 1 10b of the respective components 102a, 102b, 102 they are engaged with, such that each cap 306a, 306b, 350 general fills a space defined between the sidewalls 108, flanges 1 14 and end web 1 10b of the respective building formwork component 102a, 102b, 102. In this way, the building formwork caps 306a, 306b, 350 effectively provide a supporting function, in that they act to reduce bowing of the respective webs 110b they are adjacent to when assembled.

Variations and modifications may be made to the parts previously described without departing from the spirit or ambit of the disclosure. For example, the building formwork caps are illustrated and described as having grooves for engagement with a building formwork component. However the engagement portions of the building formwork caps may take other forms, depending on the form of the building formwork component they are intended to engage with.

I n the claims which follow and in the preceding description, 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 cap, system and connector.

Claims

1 . A building formwork system comprising: a building formwork component that comprises walls that define a cavity for receipt of a cementitious material therein, and first and second corresponding engagement portions;

a cap configured to be retained by the first and second

corresponding engagement portions of the component, the cap being further configured such that, in use, it is able to resist deflection intermediate the first and second corresponding engagement portions of the component.

2. A system according to claim 1 wherein each corresponding engagement portion is arranged at a respective sidewall of the building formwork component, whereby the sidewalls and corresponding engagement portions define a space therebetween, and wherein the cap is further configured to locate in the space so as to extend between and be retained by the first and second corresponding engagement portions of the component.

3. A system according to claim 2 wherein the building formwork component further comprises at least one web extending between its sidewalls, the at least one web further defining the space in which the cap is to locate, and wherein each corresponding engagement portion comprises a flange, each flange being disposed at a respective end of a sidewall of the building formwork component such that, when the cap is located in the space, the cap is retained therein by the flanges.

4. A system according to claim 3 wherein each flange is turned inwardly from, so as to form a right angle or acute angle with, its respective sidewall, whereby the flanges are able to retain the cap in the space.

5. A system according to claim 3 or 4 wherein the cap is configured to substantially fill the space defined between the sidewalls, flanges and web of the component.

6. A system according to any one of claims 2 to 5 wherein the cap is configured for being: slid into engagement with the first and second corresponding engagement portions of the building formwork component; snap-fit into engagement with the first and second corresponding engagement portions of the building formwork component.

7. A system according to any one of the preceding claims wherein the cap is defined by a building material that is capable of resisting deflection when located at the first and second corresponding engagement portions of the building formwork component.

8. A system according to claim 7 wherein the building material comprises a slab, sheet or panel and optionally the building material comprises fibre cement such as compressed fibre cement.

9. A system according to claim 7 or 8, when dependent on any one of claims 3 to 5, wherein the building material is retained in the space between each flange and the at least one web.

10. A system according to any one of claims 1 to 6 wherein the cap comprises: first and second engagement portions, each for engaging the corresponding first and second engagement portions of the building formwork component;

a cap portion extending between the first and second engagement portions, the cap portion being configured such that it is able to resist deflection intermediate the first and second engagement portions.

1 1. A system according to claim 10 wherein the cap portion is configured to resist deflection via an outer skin and an internal reinforcement structure.

12. A system according to claim 11 wherein the outer skin comprises two spaced walls, each generally extending between the first and second engagement portions of the cap.

13. A system according to claim 12 wherein the internal reinforcement structure comprises a plurality of webs extending between the two spaced walls of the outer skin.

14. A system according to claim 13 wherein at least some of the plurality of webs:

- extend generally perpendicularly to the two spaced walls of the outer skin; and/or

- extend diagonally between the two spaced walls of the outer skin.

15. A system according to any one of claims 10 to 14 wherein the outer skin together with the reinforcement structure comprise a truss.

16. A system according to any one of the preceding claims wherein the cap is generally defined as an elongate section.

17. A system according to claim 16, when dependent on any one of claims 10 to 15, wherein each of the first and second engagement portions of the cap extends for the length of the cap elongate section at respective first and second longitudinal sides thereof.

18. A system according to claim 17 wherein each of the first and second engagement portions of the cap comprises a longitudinal groove that extends along and adjacent to an edge of a respective longitudinal side of the cap elongate section, each groove for receipt of a

corresponding engagement portion of the building formwork component.

19. A system according to claim 17 or 18 wherein the cap is of a unitary structure such as may be moulded such as by extrusion from plastic.

20. A cap that is as defined in any one of claims 10 to 19.

21. A building formwork connector for connecting two building formwork components, each component of the type that comprises walls that define a cavity for receipt of a cementitious material therein, the building formwork connector when viewed in end profile comprising a web that extends between two flanges, each flange comprising first and second longitudinally extending edges that are turned inwardly to define first and second lips, with the flanges connected to a respective end of the web at respective intermediate flange locations between their respective first and second lips.

22. A connector according to claim 21 wherein each pair of first lips and each pair of second lips is configured for: slideable engagement with a corresponding pair of grooves formed in a respective building formwork component; snap engagement with a corresponding pair of grooves formed in a respective building formwork component.

23. A connector according to claim 21 or 22 wherein, when viewed in end profile, an outer surface of each lip defines generally a right angle or a generally acute angle with respect to a remainder of the flange.

24. A connector according to any one of claims 21 to 23 wherein the connector is generally l-shaped in end profile.

25. A building formwork system comprising: a connector as set forth in any one of claims 21 to 24;

a building formwork component that comprises walls that define a cavity for receipt of a cementitious material therein, and first and second corresponding engagement portions, each corresponding engagement portion arranged for engaging with a respective pair of first lips or second lips of the connector.

26. A building formwork system comprising: a building formwork component that comprises: walls that define a cavity for receipt of a cementitious material therein; and a first engagement portion configured according to a first connector type; and a second engagement portion configured according to a second connector type; and a building formwork connector comprising first and second sides, each of the first and second sides being configured according to the first connector type; wherein the first connector and second connector types are configured for engagement with one another.

27. A system according to claim 26 wherein the first and second connector types are configured for one or both of slideable engagement or snap engagement.

28. A system according to claim 26 or 27 wherein the building formwork connector is as set forth in any one of claims 21 to 24.

29. A system according to claim 28 wherein the first connector type comprises the first and second pairs of lips of the building formwork connector as set forth in any one of claims 21 to 24.

30. A system according to claim 28 or 29 wherein the first connector type provided on the first engagement portion of the building formwork component comprises a pair of lips, each lip turned inwardly from a respective sidewall of the building formwork component.

31. A system according to claim 30 wherein an outer surface of each lip forms a right angle or an acute angle with its respective sidewall.

32. A system according to any one of claims 26 to 31 wherein the building formwork component comprises first and second ends, the first end comprising the first engagement portion configured to the first connector type and the second end comprising the second engagement portion configured to the second connector type.

33. A system according to any one of claims 26 to 32 wherein the second connector type comprises a corresponding pair of grooves formed in the building formwork component.

34. A system according to any one of claims 26 to 33 further comprising a cap according to claim 20, wherein the first and second engagement portions of the cap are configured according to the second connector type.