A TRUSS

A truss, comprising: a first truss member; a second truss member; and a third truss member configured to join the first truss member to the second truss member; wherein the third truss member comprises an end portion comprising: a flat base; an arm; and a shoulder raised relative to the base between the base and the arm; wherein the shoulder is substantially parallel to the base.

FIELD

This relates to a truss.

BACKGROUND

A truss is an assembly of truss members (chords/webs) that creates a rigid structure. Multiple truss members are connected at nodes to form a truss. In civil engineering, trusses are commonly used in roofs, floors, bridges and towers.

SUMMARY

In a first example embodiment, there is provided a truss, comprising: a first truss member; a second truss member; and a third truss member configured to join the first truss member to the second truss member; wherein the third truss member comprises an end portion comprising: a flat base; an arm; and a shoulder raised relative to the base between the base and the arm; wherein the shoulder is substantially parallel to the base.

In a second example embodiment, there is provided a method for manufacturing a truss member, comprising: cutting a sheet of steel in a first direction at a first position; cutting the sheet of steel in a second direction that is substantially perpendicular to the first direction; cutting the sheet of steel in a third direction that is substantially parallel to the first direction at a second position different from the first position; rolling forming the sheet of metal into a substantially C-channel frame; and reducing a width of an end portion of the steel frame, the width being a lateral dimension.

A method for manufacturing a truss member, comprising: cutting an end portion of a steel frame along its height at a first longitudinal position; cutting the end portion of the steel frame along its length to a second longitudinal position; cutting the end portion of the steel frame along its height at the second longitudinal position; and reducing a width of the end portion of the steel frame, the width being a lateral dimension.

BRIEF DESCRIPTION

The description is framed by way of example with reference to the drawings which show certain embodiments. However, these drawings are provided for illustration only, and do not exhaustively set out all embodiments.

FIG.1ashows a truss according to one example embodiment.

FIG.1bshows a connection in the truss ofFIG.1a.

FIG.1cshows another connection in the truss ofFIG.1a.

FIG.2ais a top view of a connection in a truss.

FIG.2bis a perspective view of the connection ofFIG.2a.

FIG.2cis a bottom view of the connection ofFIG.2a.

FIG.2dis another perspective view of the connection ofFIG.2a.

FIG.2eis yet another perspective view of the connection ofFIG.2a.

FIG.3ais a top view of a section of a joining member according to one example embodiment.

FIG.3bis a bottom view of the joining member section ofFIG.3a.

FIG.3cis the front and back view of the joining member section ofFIG.3a.

FIG.3dis a first side view of the joining member section ofFIG.3a.

FIG.3eis a second side view of the joining member section ofFIG.3a.

FIG.4is an example method for forming a truss joining member.

FIG.5is another example method for forming a truss joining member.

FIG.6shows an example method for forming edges of a truss joining member.

DETAILED DESCRIPTION

A truss is described herein which comprises a plurality of truss members. Some of the truss members join other truss members to one another. These joining members comprise end portions comprising a flat base, two arms, and two shoulders. Preferably, all truss members are manufactured using the same type of material metal, which may be a steel.

Truss

FIGS.1a,1b, and1cshow an example truss according to one example embodiment of the invention.

The truss100comprises a plurality of truss members comprising two top chords102, a bottom chord104, and seven webs106interconnected as shown inFIG.1a. In particular, the webs106are joining members as they join the top chords102to the bottom chord104. A web106may comprise two end portions joined by a middle portion, each end portion forming a connection with a top chord102, a bottom chord104, or both.

FIG.1bshows connections108.1,108.2, and108.3in the truss100in more detail. At the connections108.1,108.2, and108.3, three central webs106.1,106.2, and106.3respectively adjoin a central portion of the bottom chord104. The end portion of each of the central webs106.1,106.2, and106.3is shown in a planar view. The end portion of one web106may be substantially structurally similar to the end portion of another web106. However, the exact dimensions may differ depending on the function of a particular web106. For example, the end portion of the central web106.2is substantially shorter than the end portion of the central webs106.1and106.3. Nevertheless, the end portions of the central webs106.1,106.2, and106.3are still substantially similar in the sense that they share key structural features. The structure of the end portion of a web106and the connection thereof are described in more detail below.

The central web106.1connects the bottom chord104to the top chord102.1via its middle portion at a connection108.4. Similarly, the central web106.3connects the bottom chord104to the top chord102.2via its middle portion at a connection108.5. Similarly, the central web106.2connects the bottom chord104to the top chord102.2as well as the top chord102.1at a connection108.6.

FIG.1cshows connections108.7and108.8in the truss100in more detail. At the connection108.7, a side web106.4adjoins the bottom chord104. At the connection108.8, the side web106.4adjoins the top chord102.1. Since the separation between the top chord102.1and the bottom chord104is sufficiently small, the side web106.4does not comprise a middle portion. That is, not every web106requires a middle portion with two end portions: the length of each portion may be adjusted to suit the function of a particular web106, and the middle portion may be omitted entirely as shown inFIG.1c.

Any one of a top chord102, a bottom chord104, and a web106may be formed using a C-channel or preferably U-channel steel frames. The type of steel may be cold-formed steel (CFS) or light gauge steel (LGS). There are apertures on the steel frames for receiving fasteners. An example method for manufacturing a web106is described in more detail below. The gauge of the C-channel steel frame may range from 0.4 mm to 3.2 mm.

Joining Member

FIGS.2a,2b,2c,2d, and2eshow two connections208.1and208.2between two joining members206.1and206.2and another truss member202, respectively. These connections208.1and208.2may be the connections108.4and108.9of the truss100. The truss member202may be a top chord (e.g.102.1or102.2) or a bottom chord (e.g.104).

As can be seen fromFIGS.2ato2e, an end portion204.1of the joining member206.1is structurally similar to an end portion204.2of the joining member206.2. Any reference to a feature of one joining member does not limit the description to that particular joining member. References may be made to multiple joining members for convenience when describing the structure of the joining members.

The end portion204has a reduced width210.1compared to the width210.2of the middle portion205of the joining member206. Similarly, the end portion204may have a reduced height212.1compared to the height212.2of the middle portion205. These reductions in width and height may be achieved as part of a steel pressing, stamping, swaging, folding, or rolling. The reduction in width may be about twice the gauge of C-channel steel frame. These reductions may be caused by the end portion being pressed inwards. In an example embodiment where the end portion has a continuously rolled profile, both the width and the height are reduced.

Structurally, the end portion204comprises a first arm214.1and a first shoulder216.1on one side of the end portion204and a second arm214.2and a second shoulder216.2on the opposing side of the end portion204. A base218is disposed between the first shoulder216.1(and the first arm214.1) and the second shoulder216.2(and the second arm214.2). A first wall220.1adjoins the base218and the first shoulder216.1. A second wall220.2adjoins the base218and the second shoulder216.2.

The base218may be substantially flat. The underside of the base218engages substantially flush with a top surface220of the truss member202. Preferably, the base218provides a large contact surface for engagement with the top surface220of the truss member202. Having a sufficiently large contact surface may improve the robustness of the connection between a joining member and a truss member, meaning a truss member or a joining member may be less likely to snap or deform near a connection under stress. In one example embodiment, the width of the base218is at least 50% of the width209of the truss member202. In one example embodiment, the length of the contact surface is at least 50% of the width209of the truss member202, the length being the length of the longest line segment enclosed by the contact surface area. In one example embodiment, the contact surface area is at least 50%. In one example embodiment, the base218is pressed inwards to a depth relative to an outer surface of the middle portion, the depth being less than or equal to the height of the arms214.1and214.2.

A fastener211(e.g. a bolt or a screw) passes through aligned apertures in the base218and the top surface220of the truss member202, which achieves the connection. While only one fastener211is shown per end portion204, multiple fasteners211may be provided in other embodiments.

The shoulders216.1and216.2are raised relative to the base218and may be substantially parallel to the base218. The shoulders216.1and216.2may each have an arcuate edge that forms part of an arc224in the top view ofFIG.2a.

The walls220.1and220.2are shown to be at an approximately 45° angle relative to the base218inFIGS.2ato2e, but the walls220.1and220.2may adjoin the base218and the shoulders216.1and216.2at a different angle. It may be preferable that the angle be between 30 to 90 degrees, preferably as near to 90 degrees as possible.

Further, the walls220.1and220.2need not be straight. Each of the walls220.1and220.2may comprise multiple sections connected in a piecewise manner. Irrespective of the shape of the walls220.1and220.2, they define a height difference between the base218and the shoulders216.1and216.2. This height difference is preferably substantially similar to the height of the arms214.1and214.2such that the shoulders216.1and216.2are substantially parallel to the base218.

The arms214.1and214.2may be substantially perpendicular to the base218. The arms214.1and214.2also abut the top surface220of the truss member202but provide a substantially smaller contact surface compared to the base218. The arms214.1and214.2may have different lengths depending on the function of the particular joining member. As an example, the arm214.1of the joining member206.2is substantially longer than the arm214.2of the joining member206.2because of the angle at which the joining member206.2adjoins the truss member202. In contrast, the arms214.1and214.2may have substantially the same lengths for the connections108.2and108.6in the truss100. While the arms214.1and214.2may be different lengths, they are substantially aligned at the end proximate the rounded tip portion222. The length of an arm214is preferably at least 50% of the width209of the truss member202.

The provision of the arms214may improve the robustness of the connection between a joining member and a truss member, meaning a truss member or a joining member may be less likely to snap or deform near a connection under stress.

The end portion204may comprise a rounded tip portion222defined by the arc224when viewed from the top. The length of the rounded tip portion22, that is, the longitudinal (lengthwise) separation between the arms214.1and214.2and the apex of the rounded tip portion222is preferably at least 20% of the width209of the truss member202. In absolute terms, the length of the rounded tip portion may be no less than 20 mm.

As can be seen most clearly inFIG.2d, the joining member206is substantially hollow and has a profile that is substantially a C-channel section. The end portion204comprises additional cut-outs near the rounded tip portion222, defined by a cutting edge228.1, another cutting edge228.2, and a further cutting edge228.3. The cutting edges228.1and228.2form a cut-out to allow the end portion204to partially receive and enclose the truss member202. The cutting edges228.2and228.3form the arm214. The cutting edges228.1and228.3may be substantially parallel to each other; the cutting edge228.2may be substantially perpendicular to the cutting edges228.1and228.3.

FIGS.3a,3b,3c,3dand3eshow the end portion204of the joining member206in isolation.

When viewed from the top (FIG.3a), the end portion204is substantially symmetrical about a longitudinal axis301(parallel to length). The reduction in width can be seen at302.

When viewed from the bottom (FIG.3b), the end portion204is substantially asymmetrical about the longitudinal axis301since tab226.2is shorter than tab226.1. The asymmetry is due to the positioning of the joining member206in a truss: the joining member206adjoins a truss member202at a substantially non-perpendicular angle. That is, an edge (dashed line202) of the truss member202is not perpendicular to the longitudinal axis301. For example, joining member206.2ofFIGS.2ato2eis such a joining member206. In contrast, a joining member206such as the joining member108.2or the joining member108.6may be substantially symmetrical about a longitudinal axis even when viewed from the bottom.

FIG.3cclearly shows the C-channel profile of the joining member206.

FIGS.3dand3eare side views of the joining member206. In this particular case, the side views are different because the joining member206adjoins a truss member202at a substantially non-perpendicular angle as explained above.

InFIG.3d, two vertical cutting edges228.1.1and228.1.2are visible. The cutting edge228.1.2corresponds to the shorter tab226.2, and the cutting edge228.1.1corresponds to the longer tab226.1. Consequently, the cutting edge228.1.1is closer to the rounded tip portion222than the cutting edge228.1.2. For the same reason, the cutting edge228.2.2is longer than the cutting edge228.2.1, and the former obscures the latter inFIG.3d. In other words, the arm214.1is longer than the arm214.2in this example embodiment. Both the cutting edge228.3.1and the cutting edge228.3.2have the same longitudinal position, but only the cutting edge228.3.2is visible since the cutting edge228.3.1is obscured.

If the joining member206were for a connection such as the connection108.2or the connection108.6, however, then only one set of cutting edges228.1,228.2and228.3would be visible in either side view.

InFIG.3e, the longer side of the end portion204is closer to the viewer, so the only visible cutting edges are228.1.1,228.2.1, and228.3.1. The cutting edges on the shorter side of the end portion204, that is, cutting edges228.1.2,228.2.2and228.3.2, are obscured by the longer side of the end portion204and the arm214.1.

The joining member206and the truss member202are preferably formed using C-channel or U-channel steel frames. The type of steel may be cold-formed steel (CFS) or light gauge steel (LGS). An example method for manufacturing a web106is described in more detail below. The gauge of the C-channel or U-channel steel frame may range from 0.4 mm to 3.2 mm.

Manufacturing

FIG.4describes a method400for manufacturing a joining member. Method400assumes a flat sheet of steel as the starting point. The type of steel may be cold-formed steel (CFS) or light gauge steel (LGS).

Method400may be more efficient than method500(described below) in mass production of joining members.

At step402, the sheet of metal is cut in a first direction. This cutting edge may become the cutting edge228.1or the cutting edge228.3once a joining member is formed. Referring to a flat sheet of metal600depicted inFIG.6, this cutting edge may be the edge602.

At step404, the sheet of metal is cut in a second direction different from the first direction. The second direction may be substantially perpendicular to the first direction. This cutting edge may become the cutting edge228.2once a joining member is formed. Referring to a flat sheet of metal600depicted inFIG.6, this cutting edge may be the edge604.

At step406, the sheet of metal is cut in a third direction. The third direction may be substantially parallel to the first direction. This cutting edge may become the cutting edge228.1or the cutting edge228.3once a joining member is formed. If the cutting edge of step502is228.1, then this cutting edge will be228.3. If the cutting edge of step502is228.3, then this cutting edge will be228.1. Referring to a flat sheet of metal600depicted inFIG.6, this cutting edge may be the edge606.

Optionally at step408, the sheet of metal is cut to from a curved edge. This curved edge may become the arc224of the rounded tip portion222once a joining member is formed. Referring to a flat sheet of metal600depicted inFIG.6, this cutting edge may be the edge608.

The cutting steps402,404and406may need to be repeated so that the resultant joining member may have four sets of cutting edges228.1,228.2and228.3, that is, one set of cutting edges on each side of each end portion of the joining member. The cutting step408may need to be repeated so that the resultant joining member may have more than one rounded tip portions222.

Cutting may comprise stamping, punching, and blanking. Each cutting edge need not be formed separately. For example, edges602,604,606, and608may be cut using two tools each having a preconfigured profile. Edges602,604, and606can be cut using a tool with a profile having two substantially parallel edges and a substantially perpendicular edge, for example the profile610. Edge608can be cut using a tool with a profile having an arcuate edge, for example the profile612.

At step410, once all cutting has been completed, a frame is formed from the sheet of metal. The sheet of metal may be folded, rolled, swaged, and/or bent into a frame, which may be a substantially C-channel frame or a substantially U-channel frame. The gauge of the frame may range from 0.4 mm to 3.2 mm.

At step412after the frame has been formed, the end portion of the frame formed at step410is pressed inwards such that its width is reduced compared to the middle portion. The height of the end portion may also be reduced. The end portion of the frame is pressed to form the structure of described above comprising the base218, the walls220, and the shoulders216. This may be done by deforming the end portion to the shape of a preformed or die. This step may require multiple pressing operations.

A middle portion of the end portion of the frame may be pressed downwards to a depth less than or equal to the height of the arm214. This forms the base218which is recessed relative to the shoulders216. Formation of the walls220necessarily reduces the width of the end portion to account for the change in elevation.

Pressing may comprise stamping and swaging.

At step414, one or more apertures are cut so that the joining member may receive one or more fasteners (e.g. fastener211) in use.

FIG.5describes a method500for manufacturing a joining member. The method500uses a C-channel steel frame as a starting point. The C-channel steel frame may be the same steel frame as that used for the top and bottom chords in a truss. The type of steel may be cold-formed steel (CFS) or light gauge steel (LGS). The gauge of the C-channel steel frame may range from 0.4 mm to 3.2 mm.

At step502, a C-channel steel frame is cut along its height at a first longitudinal position in an end portion. This may form the cutting edge228.1or the cutting edge228.3. If the cutting edge is228.3, then preferably there is a longitudinal separation of at least 20% of the width of the C-channel steel frame between the first longitudinal position and the proximate longitudinal end of the C-channel steel frame. If the cutting edge is228.1, then preferably there is a longitudinal separation of at least 70% of the width of the C-channel steel frame between the first longitudinal position and the proximate longitudinal end of the C-channel steel frame.

At step504, the C-channel steel frame is cut along its length from the first longitudinal position to a second longitudinal position in the same end portion. This forms the cutting edge228.2. As explained above, this cut preferably has a length of at least 50% of the width of the C-channel steel frame.

At step506, the C-channel steel frame is cut along its height at the second longitudinal position in the same end portion. If the cutting edge of step502is228.1, then this cut forms the cutting edge228.3. If the cutting edge of step502is228.3, then this cut forms the cutting edge228.1.

Optionally at step507, the C-channel steel frame is accurately cut to form a curved edge in the same end portion, which forms the rounded tip portion222.

Cutting may comprise stamping, punching, and blanking.

At step508, the end portion of the C-channel steel frame is pressed inwards such that its width is reduced compared to the middle portion. The end portion of the frame is pressed to form the structure described above comprising the base218, the walls220, and the shoulders216. This may be done by deforming the end portion to the shape of a preformed or die. This step may require multiple pressing operations.

A middle portion of the end portion of the frame may be pressed downwards to a depth less than or equal to the height of the arm214. This forms the base218which is recessed relative to the shoulders216. Formation of the walls220necessarily reduces the width of the end portion to account for the change in height.

Pressing may comprise stamping and swaging.

Optionally at step509, one or more apertures are punched so that the joining member

may receive one or more fasteners (e.g. fastener211) in use. Alternatively, the frame may already have a preformed aperture at an end portion before any of the above steps are performed.

At step510, the steps502,504,506,507,508and509are performed for the other end portion of the frame. A joining member is formed after step510. As explained above, the joining member may or may not comprise a middle portion.

Interpretation

A number of methods have been described above. Any of these methods may be embodied in a series of instructions, which may form a computer program. These instructions, or this computer program, may be stored on a computer readable medium, which may be non-transitory. When executed, these instructions or this program cause a processor to perform the described methods.

Where a feature is referred to as xxx but the label xxx is not present in a drawing, xxx refers generally to all subspecies (e.g. xxx.1, xxx.2, xxx.3, etc.) of the xxx class. That is, any difference between xxx.y and xxx.z is not important in the context where xxx is used in general terms.

The steps of the methods have been described in a particular order for ease of understanding. However, the steps can be performed in a different order from that specified, or with steps being performed in parallel. This is the case in all methods except where one step is dependent on another having been performed.

The term “comprises” and other grammatical forms is intended to have an inclusive meaning unless otherwise noted. That is, they should be taken to mean an inclusion of the listed components, and possibly of other non-specified components or elements.

While the present invention has been explained by the description of certain embodiments, the invention is not restricted to these embodiments. It is possible to modify these embodiments without departing from the spirit or scope of the invention.