NZ523944A - Connection between purlin and rafter being saddle slidable along rafter - Google Patents

Abstract

Purlin to rafter coupling 30 has a saddle member 52 for location and sliding on rafter 20B. The coupling also has a purlin fixture to secure or locate an end of purling 14B. By use of such coupling outer surfaces of rafter and purlin are substantially flush.

Description

, 52 3 9 44 This specification is divided out of New Zealand Patent Specification NZ 507094 (hereinafter referred to as "that invention") PATENTS FORM NO. 5 Fee No. 4: $250.00 Our Ref: 28377/5 TB i PATENTS ACT 1953 COMPLETE SPECIFICATION I PURLIN TO RAFTER COUPLING WE TUBEMAKERS OF AUSTRALIA LIMITED, an Australian company of 1 York Street, Sydney, NSW 2000, AUSTRALIA hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: PURLIN TO RAFTER COUPLING FIELD OF THE INVENTION The present invention relates generally to a purlin to rafter coupling for use with a portal frame shed. The coupling can be used in conjunction with an apex or knee connector of the portal frame shed and can be employed in a method for constructing a portal frame of the portal frame shed.

SUMMARY OF THE INVENTION The present invention provides a purlin to rafter coupling comprising: a saddle member adapted for location on and sliding 15 along the rafter; and a purlin fixture connected to the saddle member and adapted for securing to or locating one end of the purlin whereby, in use, respective outer surfaces of the rafter and the purlin are substantially flush. 20 Advantageously, frame construction can be simplified and expedited by providing for upper surfaces of the rafter and purlin to be substantially flush. In this regard, external cladding can be easily moved and located on the flush upper surfaces.

In addition, the purlin to rafter coupling can be used to couple one or more girts to an upright in a frame, such as in a portal frame shed.

Preferably two purlin fixtures are connected to opposing ends of the saddle member for location adjacent to 30 opposing sides of the rafter in use.

Preferably the or each purlin fixture is formed integrally with the saddle member. In this regard, preferably the purlin to rafter coupling is fabricated from a single steel sheet. £ 5 SE? Preferably the or each purlin fixture is formed as a shoe being shaped internally substantially complementary to a respective end of the purlin, which in use can be seated in the shoe for coupling to the rafter.

The purlin to rafter coupling according to the invention is typically used in a portal frame of eg. a portal frame shed, but is not so limited in its use.

BRIEF DESCRIPTION OF THE DRAWINGS In order to achieve a better understanding of the present invention a preferred embodiment of the invention will now be described, by way of example in use in constructing a portal frame shed, with reference to the accompanying drawings in which: Figure 1 is a perspective view of one embodiment of a portal frame shed; Figure 2 is a detailed schematic of a portal frame such as that included in the portal frame shed of Figure 1; Figure 3 is a schematic of another portal frame; 20 Figure 4 is a detailed partly exploded arrangement of an apex connection such as that of the portal frames of Figures 2 and 3; Figure 5 is a partly exploded arrangement of a knee connection of a portal frame such as that of Figures 2 and 25 3; Figure 6 is an exploded perspective view of a preferred purlin to rafter coupling in accordance with the invention; and Figure 7 is a detailed plan and elevational view of a 30 base fixture of a portal frame shed such as that of Figure 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT As shown in Figure 1 a portal frame shed 10 comprises a series of portal frames 12A to 12C which are erected in a vertical orientation and interconnected via roof purlins 5 and wall girts such as 14A to 14D and 16A to 16C, respectively.

As depicted in Figures 2 and 3 each of the portal frames such as 12B includes a pair of columns or uprights 18A and 18B together with a pair of rafters 20A and 20B. 10 Adjacent ends of the pair of rafters 2 OA and 2 OB are interconnected via an apex connector 22 so as to form an apex connection 24. An opposite end of each of the rafters 2 OA or 2 OB is connected to an upper end of one of the columns such as 18A via a knee connector 26A or 26B. 15 A lower end of each of the columns 18A or 18B is anchored to the ground, which is usually a concrete slab or foundation, via a respective base fixture 28A or 28B. The purlins of Figures 1 and 2 such as 14B individually locate between adjacent portal frames such as 12B and 12C whereas 2 0 the purlin 14C of Figure 3 extends the full length of the portal frame shed 10. In accordance with the invention opposite ends of the purlins such as 14A to 14D connect to corresponding rafters such. as 20B via a purlin to rafter coupling 30 (described in detail below). This coupling can 25 also be used to connect one or more girts to a respective column.

The purlin 14C of Figure 3 can also be anchored to the rafter 20B using a purlin to rafter strap 32, although in this case the purlin protrudes above the upper surface of 30 the rafter.

The portal frames 12A to 12C and purlins such as 14A to 14D typically employ a closed hollow section, in this example rectangular hollow section (RHS). Preferably the RHS members are those commercially available in Australia 35 under the trade mark DuraGal.

The portal frame shed 10 is designed to permit plastic failure under a specified design criterion. For example, the Australian standard presently specifies the plastic failure of building structures including portal frame sheds whereby multiple plastic hinges form upon plastic deformation of the portal frame. Although the Australian standard for plastic analysis is directed to open-sections such as universal beams or universal columns, the applicant has extended this plastic analysis to closed sections such as RHS DuraGal.

The inclusion of the apex and knee connectors such as 22 and 26A/26B, respectively, in the portal frame shed 10 allows formation of the multiple plastic hinges in plastic failure of the portal frame 10. The apex and knee connectors 22 and 26 are designed whereby plastic hinges are formed in the columns 18A/18B and rafters 20A/20B before failure of the connector 22 or 26. In this example this is achieved by the apex connector 22 and knee connector 2 6 of Figures 4 and 5, respectively.

The apex connector of Figure 4 comprises an internal sleeve 34 formed in this example from RHS spigots 36A and 36B welded to one another so as to define an obtuse angle at which the roof of the portal frame shed 10 is pitched. The apex connector 22 also includes an external sleeve 38 located over an intermediate section of the internal sleeve 34 to provide a moment connection. The external sleeve 38 in this example consists of RHS collars 40A and 40B slid over corresponding spigots 3 6A and 36B and welded to one another at the juncture of the RHS spigots 36A and 36B. The apex connector 22 thus provides telescopic connection for a pair of rafters such as 2 OA and 2 OB. The apex connector 22 is configured so that a square cut RHS rafter such as 2OA or 2OB abuts the corresponding RHS collar 4OA or 40B.

The knee connector 26 of Figure 5 is practically-identical in construction to the apex connector 22. For ease of reference like components of the knee connector 26 have been prefixed with the numeral *1". For example, the 5 internal and external sleeves are designated as 134 and 138, respectively. Otherwise, the knee connector 26 is designed at such an angle that the column such as 18A is oriented substantially upright. Once again the knee connector 26 is designed so that under plastic failure 10 multiple hinges occur within the columns or rafters 18 or 20 remote from the connectors 22 or 26.

The internal RHS sleeve 34 or 134 is rolled or formed from a steel product commercially available in Australia under the trade mark GALVABOND of a 2.5 mm or thicker 15 thickness and joined with a full strength butt weld. The external sleeve 38 or 138 is fabricated over the internal sleeve 34 or 134 with a full strength butt weld to provide the moment connection.

The square cut rafters such as 2 OA and 2OB of this 20 embodiment are DuraGal RHS of the dimensions 100 x 50 x 2.5 or thicker or 150 x 50 x 2.5 or thicker. The square cut columns 18A and 18B are of the same dimension DuraGal RHS. The particular cross-sectional dimensions may vary depending on the load requirements.

An embodiment of the invention will now be described with reference to Figure 6. This Figure illustrates the purlin to rafter coupling 30 of Figure 2 in greater detail. The coupling comprises a saddle member 52 and typically two purlin fixtures, one of which is shown as 54, located on 3 0 opposing sides and formed integrally with the saddle member 52. At an end frame, a coupling with one purlin fixture is typically employed.

The saddle member 52 is shaped complementary to the external profile of the rafter 2 0B and is designed to 35 temporarily slide along the rafter 20B prior to eg. being fastened thereto. Each of the purlin fixtures 54 is formed as a shoe having a bottom wall 56 and opposing web elements 58A and 58B connected to the saddle 52. The base wall 56 and webs 58A and 58B are fabricated so that internally the shoe is shaped complementary to an end of the purlin 14B.

In use, the purlin 14B can be seated in the shoe of the purlin to rafter coupling 30. The base wall 56 is disposed relative to the saddle member 52 such that an outer (upper) surface of the purlin 14B and rafter 20B are substantially flush with one another in use. Generally the 10 purlin to rafter coupling 3 0 is fabricated from a single steel sheet and press formed without welding.

The portal frame shed 10 of Figures 1 and 2 includes the base fixtures 28A and 28B such as those shown in detail in Figure 7. Each of the base fixtures 28 includes a base 15 plate 60 upon which a pair of opposing angle-section members 62A and 62B are welded. The angle-section members 62A and 62B are of a DuraGal material and are configured to define a locating spigot on which a lower end of one of the columns 18 locates. The base plate 60 is anchored to in 2 0 this example the concrete slab 64 via stud anchors 66A and 66B. The base fixtures 28A and 28B may be anchored to the concrete slab 64 with the stud anchors 66A and 66B located along one side, rather than at opposing ends, of the base plate 60.

The general steps involved in erection of the portal frame shed 10 described above will now be summarised: (i) the base fixtures such as 28A and 28B are located at the predetermined span apart and secured to the concrete slab for each of the portal frames such as 12B; 3 0 (ii) the required number of portal frames such as 12A to 12C are prefabricated on site with telescopic connection of the rafters and columns to the apex and knee connectors such as 22 and 26 as described above; (iii) a first of the portal frames 12A is erected upon 35 its corresponding base fixtures and temporarily strutted; (iv) a second of the portal frames 12B is erected upon its corresponding base fixtures 28A and 28B; (v) purlins such as 14A to 14D are interconnected between rafters of the adjacent portal frames 12A and 12B to stabilise the structure using respective connectors 30; (vi) a third of the portal frames 12C is erected and the remaining purlins located between adjacent portal frames 12B and 12C, making use of respective connectors 30; (vii) wall girts such as 16A to 16C are fixed between 10 adjacent columns 18 of adjacent portal frames such as 12A and 12B, again using respective connectors 30; and (viii) the portal frame shed 10 is clad in a conventional manner.

It should be appreciated that fixing or interlocking 15 of the portal frames 12A to 12C is effected using fastenings such as those commercially available in Australia under the trade name of TEK screws. Similarly the columns 18 may be fixed to the base fixtures 28 using TEK screws. Likewise, the purlins 14A to 14D may be 20 secured to the purlin to rafter coupling 30 which is then fixed to the rafter 20B via TEK screws.

Now that a preferred embodiment of the invention has been described it will be apparent to those skilled in the art that the described portal frames and sheds have at 25 least the following advantages: (i) a portal frame shed or portal frame can be constructed which permits plastic failure of the portal frame; (ii) the portal frame shed is modular and relatively 30 simple to construct requiring minimal trade skills; (iii) the portal frame shed is constructed in such a manner to eliminate or at least reduces surfaces on which dust and other contaminants can accumulate; and (iv) the portal frame sheds are aesthetically pleasing 35 because they can be constructed using closed section members.

Advantages (ii) to (iv) follow directly on from the use of a preferred purlin to rafter coupling as described above.

Those skilled in the art will appreciate that the 5 invention described herein is susceptible to variations and modifications other than those specifically described. The rafters, columns, purlins and/or girts may be formed of closed or open section members and are not restricted to DuraGal RHS. The purlin to rafter coupling would thus be 10 modified accordingly. All such variations and modifications are to be considered within the scope of the present invention.

Claims (9)

1. A purlin to rafter coupling comprising: a saddle member adapted for location on and sliding 5 along the rafter; and a purlin fixture connected to the saddle member and adapted for securing to or locating one end of the purlin whereby, in use, respective outer surfaces of the rafter and the purlin are substantially flush. 10

2. A purlin to rafter coupling as claimed in claim 1 wherein two purlin fixtures are connected to opposing ends of the saddle member for location adjacent to opposing sides of the rafter in use. 15

3. A purlin to rafter coupling as claimed in claim 1 or 2 wherein the or each purlin fixture is formed integrally with the saddle member. 2 0

4. A purlin to rafter coupling as claimed in claim 3 that is fabricated from a single steel sheet.

5. A purlin to rafter coupling as claimed in any one of the preceding claims wherein the or each purlin fixture is 25 formed as a shoe being shaped internally substantially complementary to a respective end of the purlin, which in use can be seated in the shoe for coupling to the rafter.

6. A purlin to rafter coupling as claimed in any one of 30 the preceding claims when used in a portal frame.

7. A purlin to rafter coupling substantially as herein described with reference to Figure 6 of the accompanying 11

8. A purlin to rafter coupling as claimed in any one of the preceding claims when used in a portal frame substantially as herein described with reference to the 5 accompanying drawings.

9. A purlin to rafter coupling as claimed in any one of claims 1 to 7 when used together with an apex connector or a knee connector substantially as herein described with 10 reference to the accompanying drawings. TUBEMAKERS OF AUSTRALIA LIMITED By its Attorneys 15 JAMES & WELLS