AU5716799A - Improved flitch beams, their manufacture and their use - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT, 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: GANG-NAIL GROUP LIMITED STEPHEN ANTHONY COLL A J PARK SON, Level 11, 60 Marcus Clarke Street, Canberra ACT 2601 IMPROVED FLITCH BEAMS, THEIR MANUFACTURE AND THEIR USE The following statement is a full description of this invention, including the best method of performing it known to me/us IMPROVED FLITCH BEAMS, THEIR MANUFACTURE AND THEIR USE The present invention relates to flitch beams, methods of forming flitch beams, structures made using flitch beams and related means and methods.

Flitch beams usually comprise a mixture of timber and metal members coacting to provide the requisite strength characteristics. Frequently flitch beams in the past have involved "I"beam or the like metal structures to which are attached (by bolting or otherwise) top and bottom timber plate members. The channels of such "I"beams may in addition, if desired be packed with timber plates to facilitate, for example, the attachment of wall cladding.

The present invention however recognises a simple form of flitch beam construction and it is to that and the related means and methods that the present ooo e invention is directed.

Accordingly in the first aspect the present invention consists in a flitch beam 15 comprising, in cross section, two timber or other plates (hereafter "timber plates") having sandwiched therebetween a metal member, said timber plates having been each attached to the metal member by the use of kinetic nails.

As used herein the term "kinetic nails" includes any compatible nail in so far as metal material is concerned capable under high speed actuation of penetrating the metal in between the timber plates. Preferably such a kinetic nail is of an appropriate steel and preferably is energised by a nailing gun or the equivalent such as a powder actuated RAMSETTM Gun.

Preferably said metal interposed between the timber plates is a steel.

Preferably said steel is mild steel.

Preferably said nails and the metal interposed between the timber plates coact to prevent easy withdrawal of the nails, eg, preferably there is a bursting of the metal and/or fusion between the metal components.

In some forms the beam may include butted timber plates on one or both sides of the metal.

In some forms of the present invention preferably the metal plate interposed between the cords is substantially straight whilst the timber plates may be curved or -3joined so as to define a ridge or the like.

Preferably said beam is of a kind substantially as hereinafter described irrespective of whether or not (in transverse section) each timber plate is of similar cross-section dimension and irrespective of whether or not in transverse section the metal interposed between the timber plates is co-extensive with either or both.

In still a further aspect the present invention consists in a method of forming flitch beams of any of the kinds previously defined which comprises kinetically nailing timber plates to a flitch forming metal member, each timber plate having the head of the nail adjacent an outer face of the timber plate.

In still a further aspect the present invention consists in structures formed using flitch beams in accordance with the present invention.

In a still further aspect the present invention consists in a truss form made using flitch beams in accordance with the present invention.

a further aspect the invention consists in a method of forming a structural 15 beam suitable for use in a structure, said method comprising placing a timber plate in with juxtaposition to a metal member and thereafter kinetically nailing through the timber plate in to and through the metal member a plurality of nails which will hold the timber plate and metal member in such juxtaposition.

Preferably a similar timber plate is nailed to said metal member from the 20 other side of the metal member to that of juxtaposition with said first mentioned timber plate, such second mentioned timber plate likewise being kinetically nailed.

.i Preferably both said timber plates are in juxtaposition and sandwich said metal member prior to the kinetic nailing of either or both timber plates to the metal member.

Preferably said nailing holds at least about 75% of the thickness of that timber plate through which it passes to enter said metal member.

Preferably each said nail enters into at least 25% of that timber plate, if any, on the opposite side of the metal member to that from which the kinetic nails enter said metal member from said first mentioned timber plate.

Preferably said beam produced is a flitch beam as previously defined.

Preferred form of the present invention will now be described with reference -4to the accompanying drawings in which; Figure 1 is a partial broken away isometric view of a flitch beam in accordance with the present invention showing the heads of nails that have been kinetically fired through the near timber plate to penetrate, for example, a 6mm thick mild steel flitch beam core, it being realised that a similar kinetic firing of nails from the other side is ideally utilized, Figure 2 is a side elevation of a flitch beam using a curved timber plate and a straight flitch plate, the dots showing the nailing that might be utilized to hold the components together whilst at the same time allowing the timber plates to provide an appropriate camber, Figure 3 is an alternative to the arrangement shown in Figure 2 where instead a ridge is provided by butt jointing different timber plates, in each of Figures 2 and 3 the preferred mild steel plate being shown in broken outline, 1 preeFigure 4 is a end view of, for example, a flitch beam in accordance with the present invention, Figure 5 shows a different form of flitch beam, that of Figure 4 being for example 90mm wall beam made up of 45mm timber plates and 6mm steel plate whilst that of Figure 5 is, for example, of similar width but of reduced height, and Figure 6 shows a simply supported flitch beam in accordance with the 20 present invention held by an appropriate nailing plate on both sides of the beam (for example, a 4T10 TYLOKTM plate on both sides or an 8T10 TYLOK T M plate on one .:side) and preferably with a 4T10 TYLOK T M plate or some equivalent at the top spanning between the flitch beam and the top plate, Figure 7 shows a cantilever beam reliant on a flitch beam construction in accordance with the present invention having the mating beams at the corner attached in abutment using an appropriate nailing plate such as a pair of 4T TYLOKTM plates plus a MUILTIGRIP T M fixer on the inside and showing a nailing plate attaching the flitch beam to an appropriate double stud (eg; using a 4T10

TYLOK

T M plate on both sides or an 8T10 TYLOKTM plate on one side), Figure 8 shows a flitch beam in accordance with the present invention with a mid-span camber (cambered using the natural crock), the steel flitch having been laid on one cambered timber side and then nailed as per construction details in accordance with the present invention, Figure 9 shows a similar flitch beam to that of Figure 8 but showing how the mid span camber can be provided by jigging, by wedging to the correct camber from a central lower fixed stop against the action of endwise acting fixed stops, Figure 10 shows a preferred splicing arrangement for the flitch on at least one side of a flitch beam in accordance with the present invention, the central metal extending for the full length (preferably the splicing using a nailing plate such as, for example, in a manner as shown), Figure 11 shows typical nailing details of a cantilevered flitch beam in accordance with the present invention showing a preferred nailing pattern (the dots shown denoting nailing points) along the length of the beam, there being a four nail oooo group on the left, thereafter staggered nails, a four nail group over a cantilever support position and thereafter staggered nails until another four nail group, such 15 groupings being matched more or less on the other side, (ie; nailing the other flitch to the steel plate), with preferably however the staggered nailing from the other side having the reverse stagger, a Figure 12 shows typical nailing details of beams such as those coded as FB 15L, FB25L, FB20H, FB25H and FB30H which are our codes for a series of .ooo•i 20 beams to be simply supported, there being a six nail group, a series of staggered nails, a four nail group, staggered nails and then a further six nail group, again there being some reverse staggering from the other side and similar nailing group on the other side, and Figures 12A through E show to scale relative to each other the flitch beam end profiles of the flitch beams coded by us respectively as FB15L (Figure 12A), (Figure 12 FB20H (Figure 12C), FB25H (Figure 12D) and (Figure 12E), in each instance the plate thickness (6mm or 10mm) being dictated by the or in the code and with a wooden plate of 45mm on each side or at least a wooden plate of 35mm to 45mm on at least one side, and with the depths ranging from the 130mm of Figure 12A through to the depth of 260mm of Figure 12E.

Description of Some Preferred Forms: The flitch beams arising from the present invention rely on the novel concept of strengthening timber components with a steel flitch plate sandwiched between the two layers. The timber is fixed to the flitch using high strength nails fired through to penetrate the steel section at specified locations and spacings.

The use of the flitch construction eliminates the variability of timber performance and the system allows the spanning of large openings such as garage doors, keeping the lintel depth to an acceptable minimum.

Each beam can be custom-made to measure and can be cambered to suit the application.

Preferably the present invention envisages the use of RAMSETTM or HILTITM type nails preferably using a powder actuated kinetic nailing tool such as that of o •RAMSET T M capable of penetrating both the near timber plate and the flitch beam forming mild steel plate so as to provide for sufficient penetration and timber plate 15 retention thereto.

Table 1 gives examples of different flitch beam sizes contemplated by us as a S.best mode of performing the invention, each beam with an in our code having 6mm thick mild steel whilst those with an in our code having 10mm thick mild steel.

ooooo 20 A person skilled in the art will appreciate how, with an appropriate choice of .o.o.i energy, some fusion between each nail and timber plate will occur thus maintaining :the integrity of the structure. With nailing from both sides this ensures that neither plate is likely to be easily separable from the metal core.

Major Features of Flitch Beams of Present Invention Span/Depth Ratio The beam has a large span capability relative to the depth. Where normal fully timber beams are using depths of 450mm plus for spans around the 6000mm area, the flitch beam is in most cases between 250mm and 300mm in depth.

S Comparisons to Timber Sizes Our code FB25H (250 deep side members) flitch beam is approximately equivalent to a 400mm deep solid timber beam.

Our code FB30H (300 deep side members) flitch beam is approximately equivalent to a 450mm deep solid timber beam.

Comparison to Steel UB's See the steel beam comparisons (Table 2).

TABLE 2 STEEL BEAM COMPARISON GANG-NAIL FLITCH BEAM STEEL BEAM EQUIVALENT Our Code NZ Industry Code FB25L 150UB18 150UB14 FB25H 180UB18 FB30H 200UB18 S On Site Use The ease of on site fixing is a major befit to the builders. A builder has no need to use steel cleats, bolts, welding etc. normally associated with steel beams. Conventional timber to timber fixings are used.

a a. a a..

a a. a Preferably beams of the present invention are (see Figures 12A 12E) (see 1) Table to 0 t o 0:.0

S

6.* TABLE 1 OUR CODE THICKNESS WIDTH LENGTH 6mm 130mm 3800 (Figure 12A) 6mm 130mm 2000 FB25L 6mm 200mm 5000 (Figure 12B) 6mm 200mm 3800 10mm 180mm 5000 (Figure 12C) 10mm 180mm 3800 10mm 230mm 6000 (Figure 12D) 10mm 230mm 5000 230mm 3800 10mm 260mm 6000 (Figure 12E) 10mm 260mm 5000 Storage and Handling 15 Consideration for the storage and handling of the flitch beams is the same as for trusses in general. However, particular care is required to ensure the beams stay dry by avoiding exposure to wet weather. The beams are normally marked to identify the right way up and special load bearing points if any.

Stability Top Edge Restraint The flitch beams are to be restrained along their top edge at 900mm centres maximum for heavy roof and 1200mm centres maximum for light roof.

Floor beams are restrained along their top edge at 600mm centres maximum.

Bottom Edge Restraint The flitch beams are to be restrained along their bottom edge at third span points. Bottom edge restraints are not required where purlins half the depth or more are fixed on to the side of the rafter.

-9- Timber Specification Normal F5 machine stress graded Radiata Pine or MGP10 or No. 1 framing Radiata Pine Architectural Treatment Moisture Content No. 1 framing Douglas Fir or equivalent grade of other species.

Select visually acceptable Grade as above.

Refer to NZS3602 All flitch beams are made dry, 18% or less at time of fabrication.

Steel Specification Steel flitch plates to be mild steel of thicknesses 6mm and Nail Specification The nail shall have full penetration through the steel flitch and should preferably have at least 75% bearing on the timber side plates, driven from both timber faces.

The nail is preferably to be a minimum 4mm power driven fastener, 60mm to 65mm length range and applied by a licensed powered fastener operator.

Methods of use of flitch beams in accordance with the present invention are abound.

Claims (17)

1. A flitch beam comprising, in cross section, two timber or other plates (hereafter "timber plates") having sandwiched therebetween a metal member, said timber plates having been each attached to the metal member by the use of kinetic nails.

2. A beam of claim 1 wherein each said kinetic nail is of steel.

3. A beam of claim 1 or 2 wherein each kinetic nail is energised directly or indirectly by gases of combustion or explosion of and/or in a gun.

4. A beam of any one of the preceding claims wherein said metal interposed between the timber plates is a steel. A beam of claim 4 wherein said steel interposed between timber plates is mild steel. S6. A beam as claimed in any one of the preceding claims where each said timber plate is not a laminate of wood.

7. A beam as claimed in any one of the preceding claims wherein said kinetic nails and the metal interposed between the timber plates co-act to prevent easy withdrawal of the nails.

8. A beam as claimed in claim 8 wherein the co-acting to prevent easy removal of the nails arises from, in respect of the choice of kinetic nails and the choice of the metal member, the choice of the speed of application of each kinetic nail whereby there is a penetrative bursting of the metal by each kinetic nail and/or there is some fusion between each kinetic nail and the metal member.

9. A beam of any of the preceding claims wherein the timber plates carrier a camber.

10. A beam of any one of the preceding claims wherein more kinetic nails are used in those zones along the length of the flitch beam which are to bare on an underlying support member or which are to bare under an overlying weight transmitting member than in at least most other zones along the length thereof.

11. A beam of any one of the preceding claims having dimensions substantially as hereinbefore described.

12. A beam of any one of the preceding claims having a metal member to timber -11- plate relationship substantially as hereinafter shown in any one or more of the accompanying drawings.

13. A flitch beam substantially as hereinbefore described with reference to any one or more of the accompanying drawings.

14. A truss involving a flitch beam as claimed in any one of the preceding claims. A structure formed using flitch beams as claimed in any one of claims 1 to 13.

16. A method of forming a structural beam suitable for use in a structure, said method comprising placing a timber plate in with juxtaposition to a metal member and thereafter kinetically nailing through the timber plate in to and through the metal member a plurality of nails which will hold the timber plate and metal member in such juxtaposition.

17. A method as claimed in claim 17 wherein a similar timber plate is nailed to r oloo said metal member from the other side of the metal member to that of juxtaposition w ith said first mentioned timber plate, such second mentioned timber plate likewise being kinetically nailed.

18. A method as claimed in claim 18 wherein both said timber plates are in juxtaposition and sandwich said metal member prior to the kinetic nailing of either S. or both timber plates to the metal member.

19. A method as claimed in any one of the claims 17 to 19 wherein said nailing oo 20 holds at least about 75% of the thickness of that timber plate through which it passes to enter said metal member. :20. A method as claimed in claim 20 wherein each said nail enters into at least of that timber plate, if any, on the opposite side of the metal member to that from which the kinetic nails enter said metal member from said first mentioned timber plate.

21. A method as claimed in any one of the preceding claims wherein said beam produced is a flitch beam as claimed in any one of claims 1 to 13.