EP0032417A1

EP0032417A1 - A construction device, especially for supporting shuttering

Info

Publication number: EP0032417A1
Application number: EP81300011A
Authority: EP
Inventors: David Charles Thompson; David John Stevens
Original assignee: STEVELAND BOXFORM Ltd
Current assignee: STEVELAND BOXFORM Ltd
Priority date: 1980-01-09
Filing date: 1981-01-05
Publication date: 1981-07-22
Also published as: AU6609481A; GB2067642A; JPS56142968A

Abstract

A construction device comprising primarily a beam (₁) of substantially box or channel section enclosing a timber insert (12); the box section has a portion milled out of one of its narrow webs to leave a gap (10) so that shuttering (4) can be nailed to the beam; the beam may be provided with a holdfast (2) which by means of a yoke (18) and saddle (22) secures the beam to strongbacks (3).

Description

The present invention relates to a construction device comprising a beam particularly suitable for use in formwork for moulding concrete but also suitable for other purposes.
Known construction beams for formwork are section, formed with a/hereinafter called "I" section,having two flanges interconnected by a web, one of the flanges being in the form of a channel which surrounds on three sides a timber insert. This insert is provided so that shuttering can be nailed to the beam. The section is normally made of aluminium or steel.
Whilst such a known beam is excellent for simple straight formwork, it is not suitable when the formwork has to be curved or angled. The reason is that the "I" section cannot be bent more than a very slight amount and the flanges of the "I" protrude from the central web to prevent one such beam from being - bolted closely against another such beam so as to form an angle within the plane of the central web.
A construction device according to the invention comprises a beam including a metal section having two parallel walls interconnected by a web, and a timber insert located between the walls, each said wall presenting a substantially planar exterior surface, said surfaces defining the extremities of the beam across its width.
Such a cross-sectional conformation of the beam enables one beam to lie flat on another and the one to be secured to the other by any suitable means such as bolting or clamping, and the one beam can be angled to the other. Furthermore the simple conformation of the beam enables it to be placed between rolls and curved to a desired radius which has been found to be as small as 2 metres radius. In the case when the curvature is pronounced, it is preferable to provide two or even three thin timber inserts lying one on the other in a radial direction away from the centre of curvature. This enables the timber to take up the curvature without cracking.
In a preferred embodiment of the invention the beam is formed of a standard box section with one narrow web partially cut away so that the timber insert is accessible. The beam may be provided with holes at even spacing along its length both for interconnecting beams and also for fixing with a fixing means to strongbacks or soldiers.
The fixing means preferably comprises a yoke having two-arms to embrace the webs of the beam and having a hole through the arms to receive a bolt or pin, the yoke being connected to a threaded rod.and nut to a saddle adapted to seat on a pair of strongbacks or soldiers so that on tightening the nut the saddle holds the beam against the strongbacks or soldiers.
The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which:-

Figure 1 is a partially cut away perspective view of a construction device according to the invention;
Figure 2 is a side view of the device of Figure 1;
Figure 3 is a side view of the construction device of Figures 1 and 2 showing its use for angled formwork; and
Figure 4 is a side view of the construction device of Figures 1 and 2 showing its use for curved formwork.

In the drawings a construction device is shown comprising a beam 1 and a fixing means or holdfast 2. The holdfast 2 clamps the beam 1 to a pair of strongbacks or soldier.: 3, and shuttering 4 of the laminated wood or whatever is secured to the beam 1 by nails 5.
The beam 1 is preferably formed of steel, though aluminium or alloys could be used. The beam is conveniently formed from box section steel having two parallel long side webs 6 and an interconnecting portion or short side web 7. The fourth side of the box section is milled away to provide two inwardly turned flanges 8 with a gap 10 in between. The gap 10 enables nails 5 to be hammered :nto a timber insert 12 which is forced longitudinally into the inside of the box section of the beam. The timber is any suitable timber for nailing into such as pine or elm and although is not a primarily structural component may increase the beam strength by about 8%.
The timber insert 12 is shown as a single member but if the beam 1 is to be curved radically the insert can be formed of three parts 13 indicated by broken lines 14 so that the parts lie one on the other in a radial direction away from the centre of curvature. This may be seen more clearly in Figure 4.
Through the long side webs 6 of the beam holes are drilled to receive bolts 16 which secure the holdfast 2 to the beam 1. The holes can also be used to bolt one beam onto another as will be described with reference to Figure 3. Instead of a bolt 16 other securing means such as a pin may be used.
The holdfast 2 comprises a yoke member or portion 18 here shown as welded to a threaded rod 20 but which can be a separate member with a bolt replacing the rod 20. The rod 20 is passed through a saddle 22 and secured by a nut 24 so that on tightening the nut 24 the beam 1 is drawn against the soldiers 3. The yoke 18 preferably has a gap 26 provided between it and the short web 7 so that the sides 28 of the arms 30 of the yoke lie snuggly between and separate the soldiers. The saddle 22 has flanges 32 preventing the soldiers from moving apart. In the case where the rod 20 is replaced by a bolt, the gap 26 provides room for the bolt head.
In the case where formwork has to be provided to mould say a parapet of a bridge one beam 1 can be bolted to another as is shown in Figure 3. Here beam 1' is bolted to beam 1 " by a bolt 40, the two beams being firmly held at the correct angle by two plates 42. A pad 44 is provided where necessary. The holdfasts 2 and soldiers 3 are provided in the same manner as shown in Figures 1 and 2. Shuttering 46 is nailed to beams 1' and 1" in the same manner as already described.
In the case where formwork has to be provided to mould say a curved wall, the beam 1'" shown in Figure 4 is precurved to the correct radius between rolls. If the curvature is pronounced then the insert is in separate parts 13 as already described. The soldiers and holdfasts are as before.
It will be appreciated that the use of an essentially metal beam which can have nails driven into it is not limited to supporting shuttering, but can be used for any number of diverse uses in the construction or building industry such as for decking beams for bridges, staging, walkaways or for roofing purlins. Indeed the beams can be used to form the structural components for buildings.
Although the beam 1 is described as having been formed from box section it is possible to form the the beam from deep channel section without the flanges 8. However there are some problems in forming the necessary depth of channel. Furthermore whilst the webs 6 of the beam are described in the preferred embodiment as being planar it is possible that the exterior surface can be channelled provided that the surface is mostly in a single plane, that is sufficient so that two beams can be bolted with their webs 6 lying the one on the other in a stable abutment.

Claims

1. A construction device comprising a beam including a metal box section having two parallel walls interconnected by a web, a part of the side of the section opposite the web being absent to expose the adjacent face of the insert whilst the remaining part forms a retaining means, and a timber insert located between the walls and retained by the retaining means in the box section, each said wall presenting a substantially planar exterior surface, said surfaces defining the extremities of the beam across its thickness.

2. A device according to Claim 1 wherein the retaining means of the box section comprises flanges extending from the parallel walls towards a central gap through which is exposed the adjacent face of the insert.

3. A device according to Claim 1 or Claim 2 wherein holes, passing through the walls and the insert, are distributed along the length of the beam.

4. A device according to Claim 3 further comprising fixing means including a yoke straddling the beam and having two perforated arms interconnected by a bridging element, the yoke being attached to the beam by a connector passing through the perforations in the arms and one of said holes.

5. A device according to Claim 4 wherein the yoke is connected to a saddle by a threaded rod or bolt and nut.

6. A device according to Claim 5 wherein the saddle is substantially channel-shaped to embrace one or more strongbacks.

7. A device according to any one of Claims 4 to 6 wherein, when the yoke is attached to the beam, there is a substantial space between the bridging element and the web.

8. A device according to any one of Claims 1 to 6 wherein the insert is formed by layers of timber.