GB2181467A - Elongate sections - Google Patents

Abstract

A member formed of sheet metal and suitable for use as a beam has a transverse cross-section which is generally Z-shaped. A web 11 of the member includes a flat central part 12 and, adjacent to each flange 20,22 a respective part 13, 16 inclined to the central part. Each inclined part is connected with the central part of the web by a respective intermediate part 15, 18 which projects from the central part in the same direction as does the adjacent flange. <IMAGE>

Description

SPECIFICATION Elongate sections This invention relates to elongate metal sections particularly, but not exclusively, to steel sections for use as purlins.

There is a commercial requirement to provide elongate sections of a given strength as economically as possible and an object of the invention is to provide an elongate section which achieves this requirement.

According to the present invention, we provide an elongate member comprising a web extending along the member, a first flange extending along a first margin of the web and projecting from the web in a first direction and a second flange extending along a second margin of the web and projecting from the web in a second direction, opposite to the first direction, wherein said flanges are spaced from each other in a direction transverse to said first and second directions, the web includes first and second inclined parts adjacent to the first and second flanges respectively, the web includes a central part, the web includes a first intermediate part which extends transversely from the central part in said first direction and which connects the first inclined part with the central part and wherein the web also includes a second intermediate part which extends transversely from the central part in said second direction and which connects the second inclined part with the central part.

The flange parts may be parallel to each other.

The flange parts may be at right angles to the central part.

The flange parts may each have a lip at that end of the flange part which is not connected to the web part.

Each lip may extend generally towards the other flange part.

Each lip may be inclined so as to form an obtuse inclined angle with its associated flange part.

The lips may be parallel to each other.

Each flange part may be provided with a stiffening corrugation.

The position at which each flange part joins the web part may lie in the same plane as the central part.

The intermediate part and associated inclined part may be rigidly disposed at 90".

The intermediate part may be disposed so as to form an obtuse inclined angle with the central part.

The intermediate parts may be parallel to each other.

The inclined parts may be parallel to each other.

The inclined parts may be parallel to the lips of the associated flange part.

The first intermediate part is preferably spaced from the first flange by a distance within the range one quarter to one seventh of the separation between the first and second flanges. More preferably, the first intermediate part is spaced from the first flange by a distance within the range one fifth to one seventh of the separation between the flanges.

The second intermediate part is preferably spaced from the second flange by a distance within the same range.

Each inclined part may be provided with a stiffening corrugation.

The stiffening corrugations of the flange parts may be disposed on the side of the flange part which faces the other flange part.

The stiffening corrugations provided on the inclined parts may be disposed on the same side of each inclined part and said side may be the side from which said first flange part extends transversely.

By the use of this invention the ratio of the distance between the flanges to the thickness of the material of which the section is made may be greater than can conventionally be utilised, and may particularly be greater than 130:1, and in a preferred embodiment be in the order of 150:1 The ratio of the depth of the stiffening corrugations in the flanges to the thickness of the material of which the member is made may lie in the range 4:1 to 8:1 and preferably lies in the range 5:1 to 7:1. In the preferred embodiment, this ratio is 6:1.

If stiffening corrugations are provided in each inclined part of the web, the ratio of the depth of these corrugations to the thickness of the material is preferably within the range 1:1 to 3:1.

The corrugations may be of generally of U shape, the radius of the base of the U and the radius of the corners where the limbs of the U join adjacent parts of the member being approximately two times the thickness of the material of which the member is made.

The stiffening corrugations provided in the flanges are preferably spaced from the web by a distance which is no greater than 35 times the thickness of the material of which the member is made.

The lip parts may have a length lying in the range 10 to 15 times the thickness of the material of which the section is made.

The lips may be inclined to the associated flange part at an angle not exceeding 115".

The member is preferably of such configuration and shape as to permit the member to be nested with an identical member with the web and flange parts in face to face relationship.

To this end, the member preferably has the following dimensions: The distance between the inwardly facing surface of the lip of the second flange part and the inwardly facing surface of the second inclined part is equal to, or greater than, the distance between the outwardly facing surface of the lip of the first flange part and the outwardly facing surface of the first inclined part; and the distance between the outwardly facing surface of the first flange and the inwardly facing surface of the first intermediate part is equal to or greater than the distance between the inwardly facing surface of the second flange and the outwardly facing surface of the second intermediate part.

The angle of inclination of the first inclined part to the central part is preferably equal to, or greater than, the angle of inclination of the second inclined part to the central part.

The central part is preferably flat. Each flange may be substantially flat, except for any stiffening corrugation in the flange part. Each inclined part is preferably flat but may include a stiffening corrugation.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings wherein: Figure 1 is a cross-section through a steel section for use as a purlin in a roof structure; and Figure 2 shows the section of Fig. 1 nested with an identical section.

It should be appreciated that the invention may be applied to a steel section for any other desired purpose and may also be applied to metals other than steel, and may be applied to other materials than metals.

Referring to the drawing, a section 10 comprises a web 11 having a central planar part 12 and a first inclined part 13 connected to one end 14 of the central part 12 by a first intermediate part 15 which extends transversely away from the central part 12 on one side A of the web part. The web also has a second inclined part 16 connected to the other end 17 of the central part 12 by a second intermediate part 18 which extends transversely away from the central part 12 on the other side B of the web 11.

There is a first flange 20 at one end 21 of the web which extends transversely away from the web 11 on the side A thereof whilst there is a second flange 22 at the other end 23 of the web 11 which extends transversely away from the web 11 on the other side B thereof.

The first and second flanges 20, 22 are generally flat, are parallel to each other and are disposed in respective planes which are at right angles to the plane in which the central part 12 lies.

The first flange 20 has a terminal first lip 24 at the end 25 thereof distant from the web 11 whilst the second flange 22 has a terminal lip 26 at the end 27 thereof distant from the web 11.

The first and second lips 24, 26 are inclined to the associated flange parts 20, 22 respectively at an obtuse included angle which, in the present example, is 110 . If desired, however, the angle may lie within the range 115 to 90" and in this specification the term "obtuse included angle" is intended to include an angle of 90".

The lip parts 24 and 26 are advantageously inclined to the plane of the central part 12 at an angle of between 10 and 25 , preferably lying within the range 15 to 22", being in the present example about 20 . Preferably the first and second inclined parts 13 and 16 are parallel to their associated lip parts 24 and 26, but may be inclined at an angle of up to 10 to the lip parts.

Whilst the inclined parts 13, 16 in the present example are parallel to the lips 24, 26, this is not essential.

A first stiffening corrugation 30 is provided in the first flange part 20, whilst a second stiffening corrugation 33 is provided in the second flange part 22. These stiffening corrugations are each of generally U configuration, the depth of the corrugations 30 and 33 being six times the thickness of the material of which the member is made. The radius of the base of the U and the radius of the curve formed between the limbs of the U and the adjacent parts of the section are both approximately twice the thickness of the material of which the member is made.

The distance, d, between the inwardly facing surfaces 20a, 22a of the flange parts 20, 22 respectively is, in the present example, one hundred and fifty times the thickness, t, of the material of which the section is made and the depth of the lips 24, 26 in the present example is 10.6 times the thickness of the material t but may lie in the range ten to fifteen times the thickness t.

The spacing of the first intermediate part 15 from the first flange 20 and the spacing of the second intermediate part 18 from the second flange 22 are both approximately equal to one fifth of the spacing d between the flanges. As pointed out hereinafter, that dimension of the first inclined part 13 which extends from the first flange 20 to the first intermediate part 15 is slightly different from the corresponding dimension of the second inclined part 16. Accordingly, whilst the corner between the central part 12 and the second intermediate part 18 is preferably spaced from the plane containing the surface 22a by a distance which is one fifth of the distance d, the spacing from the plane of the surface 20a of the corner between the central part and the first intermediate part 15 will be slightly different.

The angle between the inclined parts 13, 16 and their associated intermediate parts 15, 18 is a right angle. Each inclined part is inclined to the central part 12 at an angle within the range 10 to 30".

As best shown in Fig. 2, the section above described, marked P in Fig. 2, is capable of nesting with an identical section marked Q. In Fig. 2 the parts are identical using the same reference numerals as used in Fig. 1 but with the addition of P or Q respectively. The shape and configuration of the section is arranged to permit of this nesting and in particular the distance between the inwardly facing surface 26a of the second lip 26 and the inwardly facing surface 16a of the second inclined part 16 is equal to, in the present example, although it could be greater than if desired, the distance between outwardly facing surface 24b of the first lip 24 and the outwardly facing surface 13b of the first inclined part 13.In addition, the distance between the outwardly facing surface 20b of the first flange 20 and the inwardly facing surface 15a of the first intermediate part is equal to, in the present example, but could be greater than, if desired, the distance between the inwardly facing surface 22a of the second flange 22 and the outwardly facing surface 18b of the second intermediate part 18. Moreover, the angle of inclination of the first inclined part 13 to the plane of the central part 12 is equal to, in the present example, but may be greater than, if desired, the angle of inclination of the second inclined part 16 to the plane of the central part 12.Furthermore, the first strengthening corrugation 30 provided in the first flange part 20 has an outwardly facing surface 30b of a configuration corresponding to the inwardly facing surface 33b of the second strengthening corrugation 33 of the second flange part 22 so that the second strengthening corrugation 33 may lie within the first strengthening corrugation 30 when the sections are nested.

If required, stiffening corrugations similar to the corrugations 30 and 33 may be provided in the first and second inclined parts 13, 16.

If such stiffening corrugations are provided in the inclined parts, then both of these corrugations project towards the same side of the web so that, when the sections are nested as shown in Fig. 2, the corrugations in inclined parts of one section will lie back-to-back with the corrugations in the inclined parts of the other web and there will be no mutual contact at the corrugations in the inclined parts.

It will be understood that the transverse cross-section of each member is generally uniform throughout its length and each member is of indeterminate length, many times the separation between the flanges. Generally, the length of each member will be restricted, in order to facilitate handling of each member by two persons only. Members as shown in Fig.

1 may be joined together in end-to-end relation by overlapping both members with a relatively short connector having the same transverse cross-section and arranged in nested relation with the two longer members, as shown in Fig. 2. Alternatively, respective end portions of the two members may be overlapped one with the other, in which case one member is rotated through an angle of 1800 relative to the other member, as shown in Fig. 2. It will be noted that, when two members are nested as shown in Fig. 2, the central parts are in face-to-face contact,and can easily be secured to each other by fasteners.

Fig. 1 shows that there is adjacent to the central part 12, adjacent to one face thereof, a space which is not obstructed by the member at a level below the central part. This space is therefore available to accommodate attachments, such as are commonly used to suspend further members from a purlin.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (10)

1. An elongate member comprising a web extending along the member, a first flange extending along a first margin of the web and projecting from the web in a first direction and a second flange extending along a second margin of the web and projecting from the web in a second direction, opposite to the first direction, wherein said flanges are spaced from each other in a direction transverse to the said first and second directions, the web includes first and second inclined parts adjacent to the first and second flanges respectively, the web includes a central part, the web includes a first intermediate part which extends transversely from the central part in said first direction and which connects the first inclined part with the central part and wherein the web also includes a second intermediate part which extends transversely from the central part in said second direction and which connects the second inclined part with the central part.

2. A member according to Claim 1 wherein the first intermediate part is spaced from the first flange by a distance within the range one quarter to one seventh of the separation between the webs.

3. A member according to Claim 1 wherein the first intermediate part is spaced from the first flange by a distance within the range one fifth to one seventh of the separation between the webs.

4. A member according to any preceding Claim wherein the shape of a cross-section of the member in a plane transverse to its length is such that the appearance of the member is not substantially modified by rotation of the member through an angle of 1800 about a longitudinal axis at the centre of the web.

5. A member according to Claim 4 wherein the dimensions of the first flange relative to the second flange and of the first inclined por tion relative to the second inclined portion are such that the member can be nested with an identical member rotated through an angle of 1800 relative to the first-mentioned member, respective central parts of the members being in face-to-face contact with each other in the nested condition.

6. A member according to any preceding Claim wherein each of said first and second inclined parts is inclined substantially at a right angle to the corresponding intermediate part.

7. A member according to any preceding Claim wherein the central part of the web is flat and the flanges are both substantially perpendicular to the central part.

8. A member according to any one of Claims 1 to 6 wherein the central part of the web is flat and defines a reference plane midway between opposite faces of the central part, the first flange lies entirely to one side of said plane and the second flange lies entirely to the opposite side of said plane.

9. A member substantially as herein described with reference to and as shown in the accompanying drawing.

10. Any novel feature or novel combination of features disclosed herein or in the accompanying drawing.