GB2082648A - Building frame truss - Google Patents

Abstract

This invention relates to triangular roof trusses which are adapted to form part of the frame for an upper or sole storey within a roof, in order to make the trusses of manageable height for transport and handling, the truss is divided at the level of ceiling support bracing member 15, which is in two parts 16 and 16b each joined to spacers 16c. The side frame members 14 are formed in two parts 14a and 14b,which may overlap in the region of the member 16 to form a scarf joint. The truss has a central structured member 17. <IMAGE>

Description

SPECIFICATION Building frame truss This invention relates to building frame trusses and more particularly to a truss arrangement to form a frame for an upper storey (or a sole storey) and the robf of a building such as a two storey house or a bungalow.

In my patent application No. 7829864, published under No. 2027476, there is described and claimed a building having a roof supported by triangular trusses, said roof embodying a storey of said building, wherein a number of said trusses are provided with a structural member which extends, from the apex of the truss, in the central longitudinal plane of said storey so as to contact and partially support the base of said bruss, said base of said truss acting as a floor member for the said storey.

There is also described and claimed a triangular roof truss being substantially isosceles in shape and of such dimensions that a storey of a building may be provided within a roof incorporating a plurality of such trusses, wherein said truss is provided with a structural member which bisects the apex angle and joins the apex of the truss to its base.

The overall dimensions of such a truss makes its transport difficult since although its lengthy may be accommodated on a suitable vehicle, the height is so great that it will not pass under low bridges.

Manhandling is also somewhat difficult with a truss of this size.

It is proposed in that application that the truss be split along the central structural member but this still leaves a very large half-truss.

According to a first aspect of the present inven tion, there is provided a triangular building truss of such dimensions that a storey of a building may be incorporated above the base of the triangle within a roof incorporating a plurality of such trusses, the truss having a further bracing member parallel with the base to support a ceiling of such a storey, and a central structural member extending substantially vertically between the base and the further bracing member, rafters forming the equal sides of the triangle being divided at substantially the level of the further bracing member and the further bracing member being divided so that the truss may be manufactured in two parts to be joined together on site.

e According to a second aspect of the invention there is provided a building having an upperstorey or a sole storey in a roof incorporating a plurality of trusses according to the invention as set forth above.

It has been found that dividing the additional reinforcing member, which implies it is made up of two reinforcing members joined together, provides such reinforcement of the frame that it is not necessary to extend the vertical structural member right to the apex of the roof.

The invention will be further described with refer ence to the accompanying drawing, of which the single Figure is a diagrammatic illustration of a truss, in accordance with one form of the invention in position on the supporting walls.

The single Figure of drawing is similar two the Figure of my earlier application 7829864, published under No.2027476. It will be appreciated that the truss illustrated may be employed in a building in a manner similar to that described with reference to Figure 2 of the earlier application, the contents of which are imported hereinto by reference. The truss may also be employed as a frame for a single storey building.

It will be seen that the truss herein illustrated is shown as resting on a pair of vertical walls 11 and has a base frame member 12 which rests on the walls 11 by means of wall plates 13. The walls 11 may be walls of a lower storey or they may be footings of a single storey building. The truss further comprises equal side frame members 14joined to the base member 12 and joined together at an apex 15. In the case of a two storey building, the base member 12 forms a ground floor ceiling support and an upper storey floor support, and parallel with the base member 12 there is provided an additional bracing member 16 at ceiling level for the upper storey and extending between the frame members 14 and parallel with the base member 12. A vertical structural member 17 extends between the base member 12 and the bracing member 16, preferably joining the mid-points thereof.However, it is wished to provide more than one division of the upper storey transversely of the trusses, then more than one member 17 could be provided.

Also provided are short vertical braces 18 substantally in extension of the walls 11 and which form the basis of vertical walls in the upper storey. It will be seen that the eaves area of the roof overhangs the walls 11 fairly substantially.

In order for the floor space of the first floor to be comparable with that of the ground floor and for the first floor to be of substantially conventional height, the trusses may be constructed with dimensions such that the house has large cantilever eaves, the angle of the roof being in the region of 55" in the present instance. The cantilever eaves contribute to the balance of the loading on the floor and other members. The large eaves also provide a certain degree of weather protection for the walk ways and walls of the house. This can be particularly advantageous in the case of solid walled, c.f. cavity walled, buildings.

In order to reduce the overall dimensions of the truss for transport purposes, it is divided at the level of the bracing member 16. For this purpose, the bracing member 16 is formed of a lower beam 16a and an upper beam 16b of somewhat less width. For example, the lower beams 16a may be 46mm by 145mm whereas the upper beam 1 6b is 46mm by 97mm. At the level of the division, there are provided spacers 16c extending along the roof. These are nailed on site to the beams 16a after erection of the lower truss halves and the beams 1 6b are then nailed to the spacers 1 6c after erection of the upper truss halves.The side frame members 14 are formed of lower rafter members 14a and upper rafter members 14b which overlap in the region of the bracing members 16 in the manner of a scarf joint and the two rafter members are nailed together on site.

In view of the very considerable strength provided by the double beam construction of the bracing member 16, there is no need to provide any vertical structural members between this beam and the apex 15. In addition, the splitting of the truss at the ceiling height of the upper or sole storey means that the maximum height of the truss is the height of one storey from floor to ceiling, namely something in the region of 2.4 metres so that the overall height of a load of trusses is such that most low bridges can be negotiated.

Further lateral stiffening of the roof between the trusses is provided after erection.

Various modifications may be made within the scope of the invention.

Claims (3)

1. Atriangular building truss of such dimensions that a storey of a building may be incorporated above the base of the triangle within a roof incorporating a plurality of such trusses, the truss having a further bracing member parallel with the base to support a ceiling of such a storey, and a central structural member extending substantially vertically between the base and the further bracing member, rafters forming the equal sides of the triangle being divided at substantially the level of the further bracing member and the further bracing member being divided so that the truss may be manufactured in two parts to be joined together on side.

2. A triangular building truss substantially as hereinbefore described with reference to the accompanying drawing.

3. A building having an upper or sole storey in a roof incorporating a plurality of trusses as claimed in claim 1 or 2.