AU2004225905B2 - Truss-purlin connection and truss-batten connection - Google Patents

Description

TRUSS-PURLIN CONNECTION & TRUSS-BATTEN CONNECTION

FIELD OF THE INVENTION

The invention relates to the connection of steel roof purlins and/or steel ceiling battens to steel roof trusses.

BACKGROUND ART

Historically, the structural framing of houses has been manufactured from lengths of timber. More recently, steel framed houses have become more popular. The benefits of steel framing, in addition to termite and fire-resistance, include accuracy of manufacture and ease of assembly.

Where possible, the steel frames are assembled in the factory prior to transport to the site as this is cost-effective and minimises the amount of skilled labour required on-site. Typically, wall frames and roof trusses are assembled in the factory, whilst roof purlins and ceiling battens are screwed or nailed to the roof trusses on-site.

The present invention aims to provide an on-site system for connecting the roof purlins and/or ceiling battens to the roof trusses which requires the minimum amount of labour and skill.

SUMMARY OF INVENTION The present invention provides a truss-purlin assembly and truss-batten assembly according to the following claims. Preferred features of the invention will be apparent from the dependant claims and from the following description of the preferred embodiment.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in a non-limiting manner with respect to a preferred embodiment in which:-

FIG 1 is an elevation view of a roof truss, also including expanded detail views, and top-side and under-side plan views of the expanded detail views.

FIG 2 is a perspective view of a partially cut-away truss-purlin assembly, also including expanded detail views.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

With reference to FIG 1 there is illustrated a conventional truss 10 for a pitched roof. However, the invention is equally applicable to other types of trusses. The truss is comprised of upper chord 12, lower chord 14 and bracing or web members 16 extending therebetween in a diagonal fashion. Parallel roof purlins 18 are provided at spaced locations across the upper chord 12, and similarly ceiling battens 20 are provided at spaced locations across the lower chord 14. The interconnection of the roof purlins 18 with the upper chord 1 will now be described with reference to FIG 2. It should be noted that the interconnection of ceiling battens 20 with lower chord 14 is identical and therefore no specific description of the interconnection of ceiling battens 20 with lower chord 14 is provided.

With reference to FIG 2, there is shown a partially cutaway view of upper chord 12 and roof purlin 18. Tabs 22 are punched from the upper surface of upper chord 12 and tabs 22 extend towards each other in opposed fashion.

Roof purlin 18, which is substantially top-hat-shaped in cross-section, includes a pair of lower flanges 24 which each terminate in corrugated lateral edges 26. When assembled as shown in FIG 2, the corrugated lateral edges 26 are engaged by the tabs 22. The corrugations define peaks and valleys and tab 22 is received in one of the valleys, which is of course disposed between adjacent peaks. Accordingly, the roof purlin 18 cannot move in a direction parallel to its longitudinal axis relative to the upper chord 12 due to the interference of the tab 22 with the peaks of the corrugated lateral edge 26.

Roof purlin 18 is formed of a material which is sufficiently resilient (e.g. light gauge steel) such that flanges 24 can be resiliently deflected towards each other in the direction of arrows 28. Hence, during assembly of the roof purlin 18 with the upper chord 12 a compressive force is applied to the roof purlin in the direction of arrows 28 such that the flanges 24 deflect inwardly towards each other. Preferably, this compressive force is applied manually. The compressed roof purlin is then placed on the upper chord 12 and the compressive forces released such that oppositely extending flanges 24 each extend under and engage with tabs 22. Once engaged, the corrugated lateral edge 26 prevents relative longitudinal sliding of the roof purlin 18 relative to the upper chord 12.

Another feature of the purlin, which is not illustrated, is that the upper flange of the purlin (ie the "top" of the top-hat) is perforated or punched to provide a cheese-grater-like effect to enhance the co-efficient of friction between the soles of the boots of a person standing on the purlin and the purlin itself. Preferably, the cheese-grater-like surface is coated with a wax-like polymer material which prevents any cutting of the hands during initial handling of the purlin, but which is sufficiently plastic under the full weight of a person's boot to allow engagement of the sole of the boot with the cheese-grater-like surface.

As mentioned above, engagement of the ceiling battens 20 with the lower chord 14 is identical in nature to the engagement of the roof purlin 18 with the upper chord 12.

The invention provides an assembly system and method which requires no tools or fixing devices such as screws, nails, etc. Accordingly, the only labour and skill required on site is to compress the roof purlin or ceiling batten and engage the flanges 24 with the tabs 22. Thereafter, the purlin or batten is fixed and prevented from either separating from the chord or alternatively moving longitudinally relative to the chord. Another benefit of the present invention is that the location of the roof purlins, which is generally dictated by the size of the tiles to be used on the roof, is fully laid out with no possibility of human error on site. Hence, once the tiles are selected, the lay out of the purlins is determined by the location at which the tabs are punched out of the chord.

Claims (8)

1. A truss-purlin assembly including:- a roof truss having an upper chord adapted to receive a roof purlin on an upper surface thereof, the upper chord having a pair of opposed tabs spaced along the length of the upper chord and adapted to receive a roof purlin therebetween; a roof purlin having a pair of spaced flanges extending away from each other, said spaced flanges being resiliently deflectable towards each other to a compressed configuration whereat they can be inserted between said opposed tabs during assembly, and thereafter returning to a non-compressed configuration whereat they engage said opposed tabs.

2 A truss-purlin assembly as claimed in claim 1 , wherein at least one of said flanges is corrugated along its length and wherein the tab extends between adjacent corrugations to prevent movement of the roof purlin relative to the truss in a direction along the length of the roof purlin.

3. A truss-purlin assembly as claimed in claim 1 , wherein both of said flanges are corrugated along their lengths and wherein the tabs extend between adjacent corrugations in each flange to prevent movement of the roof purlin relative to the truss in a direction parallel to the length of the roof purlin.

4. A truss-purlin assembly as claimed in claim 1 , wherein the roof purlin is substantially "top-hat" shaped in cross-section.

5. A truss-batten assembly including:- a roof truss having a lower chord adapted to receive a ceiling batten on a lower surface thereof, the lower chord having a pair of opposed tabs spaced along the length of the lower chord and adapted to receive a ceiling batten therebetween; a ceiling batten having a pair of spaced flanges extending away from each other, said spaced flanges being resiliently deflectable towards each other to a compressed configuration whereat they can be inserted between said opposed tabs during assembly, and thereafter returning to a non-compressed configuration whereat they engage said opposed tabs.

6. A truss-batten assembly as claimed in claim 5, wherein at least one of said flanges is corrugated along its length and wherein the tab extends between adjacent corrugations to prevent movement of the ceiling batten relative to the truss in a direction along the length of the ceiling batten.

7. A truss-batten assembly as claimed in claim 6, wherein both of said flanges are corrugated along their lengths and wherein the tabs extend between adjacent corrugations in each flange to prevent movement of the ceiling batten relative to the truss in a direction parallel to the length of the ceiling batten.

8. A truss-batten assembly as claimed in claim 1 , wherein the ceiling batten is substantially "top-hat" shaped in cross-section.