GB2383808A

GB2383808A - Wooden beam with curved web

Info

Publication number: GB2383808A
Application number: GB0300186A
Authority: GB
Inventors: Andrew Michael Mcready
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-01-05
Filing date: 2003-01-06
Publication date: 2003-07-09
Also published as: GB0300186D0; GB0200208D0

Abstract

A beam comprises a pair of parallel elongate wooden members 10, 11 connected by a curved web 12 which may be in the form of a sinusoidal wave and may be fabricated from plywood. The web is bonded into regularly spaced rebates in the opposed faces of the wooden members using glue. Service pipes and cables may be passed between the wooden members. Gusset plates (13, Fig 2) may be provided at the ends of the wooden members.

Description

BEAMS Field of the Invention This invention relates to beams and is particularly concerned with the provision of an improved form of beam which can be used in flooring and ceiling constructions and which offers advantages as compared with currently available beams and joists used for this purpose.

It is also an object of the present invention to provide an improved method of making a beam.

A further object of the present invention is to provide a kit of parts for making beams which can readily be pre-packaged into a relatively compact pack such that transport of the kit is facilitated.

Summary of the Invention According to a first aspect of the present invention there is provided a beam comprising a pair of parallel elongated wooden members interconnected by a curvate web bonded into rebates in the opposed faces of the wooden members.

The curvate web preferably has a regular repeated profile which has a predetermined pitch corresponding to the spacing between adjacent rebates in the opposed faces of the wooden members.

The curvate web may be of any convenient profile. For example, the web may comprise a series of alternately facing semi-circular or semi-elliptical formations, or it may be in the form of a sine wave. It may also be of repeated parabolic form.

The curvate web is conveniently formed of plywood of an appropriate thickness to afford the required strength for the complete beam and is of such width that the web occupies only a minor part of the space between the two wooden members.

When, therefore, the beam is used as a floor or ceiling joist, substantial space is available between the two wooden members for the passage of service pipes and conduits, for example, central heating pipes, water supply and waste pipes and electrical cables.

An important advantage of the beam of the present invention as compared to beams and joists produced using metal plates to interconnect two wooden flanges is that the beam can be produced solely from wooden elements, e. g. solid timber for the wooden members and plywood for the curvate web. This means that there will be little tendency for condensation to take place on

the curvate web, which can occur on the metal interconnecting plates that have previously been used.

The rebates formed at intervals in the opposed faces of the wooden members preferably extend for only a part of the width and only a part of the height or depth of the respective wooden members and the bases of the rebates are preferably of curvate form, complementary to the contiguous surfaces of the curvate web. Bonding of the respective portions of the curvate web into the rebates is preferably effected by gluing.

Gusset plates are preferably provided at the ends of the wooden members and conveniently comprises two spaced parallel plywood sheets bonded into recesses in the end portions of the opposed, faces of the wooden members with a plywood spacer block having a thickness corresponding to that of the curvate web interposed between the plywood sheets.

The curvate web is preferably of a standard length such that, if the length of the beam which is required is greater than that of said standard length, two or more curvate webs will be used and one or more intermediate gusset plates will be used at an appropriate position or positions along the length of the beam. The adjacent ends of the curvate webs will then fit between the plywood sheets of the gusset plate (s).

According to a second aspect of the present invention there is providing a method of making a beam which comprises

providing a pair of parallel elongated wooden members the opposed faces of which are formed with spaced rebates and interconnecting the wooden members by means of a curvate web bonded into rebates in the opposed faces of the wooden members.

Gusset plates may be provided, as described above, which are bonded to the ends of the wooden members and, if required, to an intermediate position or positions along the length of the wooden members.

Production of the curvate web and the gusset plates and rebating of the wooden members may be effected at one location, with gluing of the curvate web and of the gusset plates to the wooden members effected on site.

According, therefore, to a third aspect of the present invention, there is provided, a kit of parts for use in assembling beams comprising a plurality of elongate wooden members with rebates formed at regular intervals in a presented face of each wooden member, curvate webs having a repeated profile with a pitch corresponding to the spacings between the rebates in the wooden members and gusset plates for attachment to the wooden members.

It is thus possible to package the kit of parts at a first location, i. e. one in which there are facilities for the manufacture of curvate plywood webs, and then to ship the kit of parts to a second

location, for example, in a third world country in which such facilities are not available, and then glue the beam components together on site.

The glued joints between the curvate web and the wooden members are preferably circular or similar biscuit joints which are of high strength and provide good resistance against rotation of the web relative to the wooden members, thereby providing a high performance beam.

The use of gusset plates to allow for the jointing of the curvate web at a central position and at the ends of the beam permits the beam to be manufactured at any desired length with the restriction of having to consider a fixed or pre-designed pitch of any central web compartment.

Brief Description of the Drawings Figure 1 is a side view of part of a beam, and Figure 2 is an end view of the beam showing the provision of a gusset plate at the end of the beam.

Description of the Preferred Embodiment The beam shown in the drawings comprises two parallel elongated wooden members 10 and 11 that are of standard length and are of uniform cross-section, apart from regularly spaced

rebates formed in the mutually opposed faces of the two wooden members 10 and 11. The two wooden members are interconnected by a curvate plywood web 12 that, as shown, is of sinusoidal form. The bases of the rebates formed in the opposed faces of the two wooden members 10 and 11 are of complementary configuration to the contacting surfaces of the curvate web 12 and the widths of the rebates are such that the curvate web 12 is a reasonably close fit in the rebates. The rebates typically have a width that is about half the width of the associated wooden member 10,11 and a depth that is about a third of the depth of the associated wooden member 10, 11.

As can be seen from Figure 1, the curvate web 12 occupies only a minor proportion of the space between the two wooden members 10 and 11. When, therefore, the beam is used as a floor or ceiling joist, substantial space is available between the two wooden members 10 and 11 for the passage of service pipes and conduits, for example, central heating pipes, water supply and waste pipes and electrical cables.

An important advantage of the beam of the present invention as compared to beams and joists produced using metal plates to interconnect two wooden flanges is that the beam can be produced solely from wooden elements, e. g. solid timber for the wooden members 10 and 11 and plywood for the curvate web 12.

There will thus be little tendency for condensation to take place on the curvate web 12, which can occur on the metal interconnecting plates that have previously been used in floor and ceiling beams.

The portions of the curvate web 12 that fit in the rebates in the elongated wooden members 10 and 11 are glued in position.

The glued joints between the curvate web 12 and the wooden members 10 and 11 are circular or similar biscuit joints which are of high strength and provide good resistance against rotation of the web 12 relative to the wooden members 10 and 11, thereby providing a high performance beam.

The web 12 can be of other regular curvate form. For example, the web 12 may comprise a series of alternately facing semi-circular or semi-elliptical formations. The bases of the rebates in the two wooden members 10 and 11 will then be of complementary, mating configuration.

I Gusset plates 13 are normally provided at the ends of the wooden members 10,11. Each gusset plate 13 comprises two spaced parallel plywood sheets 14 and 15 bonded into recesses in the end portions of the opposed faces of the wooden members 10 and 11 with a plywood spacer block 16 having a thickness corresponding to that of the curvate web 12 interposed between the plywood sheets 14 and 15.

The curvate web 12 is of a standard length such that, if the length of the beam that is required is greater than that of said standard length, two or more curvate webs 12 will be used and one or more intermediate gusset plates 13 will be used at an appropriate position or positions along the length of the beam.

Production of the curvate web 12 and the gusset plates 13 and rebating of the wooden members 10 and 11 may be effected at one location, with gluing of the curvate web 12 and of the gusset plates 13 to the wooden members 10 and 11 effected on site.

It is thus possible to package a kit of parts at a first location, i. e. one in which there are facilities for the manufacture of curvate plywood webs, and then to ship the kit of parts to a second location, for example, in a third world country in which such facilities are not available, and then glue the beam components together on site.

Claims

Claims :-

1. A beam comprising a pair of parallel elongated wooden members interconnected by a curvate web bonded into rebates in the opposed faces of the wooden members.

2. A beam as claimed in Claim 1, in which the curvate web has a regular repeated profile which has a predetermined pitch corresponding to the spacing between adjacent rebates in the opposed faces of the wooden members.

3. A beam as claimed in either of the preceding claims, in which the curvate web comprises a series of alternately facing semi-circular or semi-elliptical formations.

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4. A beam as claimed in Claim 1 or Claim 2, in which the curvate beam is in the form of a sine wave.

5. A beam as claimed in any one of the preceding claims, in which the curvate web is formed of plywood of an appropriate thickness to afford the required strength for the complete beam.

6. A beam as claimed in Claim 5, in which the curvate web is of such width that it occupies only a minor part of the space between the two wooden members.

7. A beam as claimed in any one of the preceding claims, in which the rebates formed at intervals in the opposed faces of the

wooden members extend for only a part of the width and only a part of the height or depth of the respective wooden members.

8. A beam as claimed in Claim 7, in which the bases of the rebates are of curvate form, complementary to the contiguous surfaces of the curvate web.

9. A beam as claimed in any one of the preceding claims, in which bonding of the respective portions of the curvate web into the rebates is effected by gluing.

10. A beam as claimed in any one of the preceding claims, in which gusset plates are provided at the ends of the wooden members.

I

11. A beam as claimed in Claim 10, in which each gusset plate comprises two spaced parallel plywood sheets bonded into recesses in the end portions of the opposed faces of the wooden members with a plywood spacer block having a thickness corresponding to that of the curvate web interposed between the plywood sheets.

12. A wooden beam substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

13. A method of making a beam which comprises providing a pair of parallel elongated wooden members the opposed faces of which are formed with spaced rebates and interconnecting the

wooden members by means of a curvate web bonded into rebates in the opposed faces of the wooden members.

14. A method as claimed in Claim 13, in which gusset plates are provided which are bonded to the ends of the wooden members and, if required, to an intermediate position or positions along the length of the wooden members.

15. A method of making a wooden beam substantially as hereinbefore described with reference to the accompanying drawings.

16. A kit of parts for use in assembling beams comprising a plurality of elongate wooden members with rebates formed at regular intervals in a presented face of each wooden member, curvate webs having a repeated profile with a pitch corresponding to the spacings between the rebates in the wooden members and gusset plates for attachment to the wooden members.

17. A kit of parts for use in assembling beams substantially as hereinbefore described with reference to and as shown in the accompanying drawings.