GB2354538A - A cold formed metal structural member - Google Patents

Abstract

An elongate structural member is produced by cold forming sheet metal, which has a series of recesses (34a, fig 5) and projecting parts (34, 35, fig 5). To form the structural member, the metal sheet is folded so that the projecting parts and recesses overlap at one edge (fig 6 and 7). The structural member is a hollow tube and has a separately formed attachment component (52, figs 9-11b), fastened thereto.

Description

2354538 PATENTS ACT 1977 JNL/AI0236GB Title: Structural Members

Description of the Invention

This invention relates to an elongate structural member of tubular shape. Generally the tubular shape is of substantially similar internal and external crosssectional conflauration and such confi-uration is generally square or rectang lar but IM OU may be made of any other desired closed polygonal cross-sectional configuration, such C as rectangular or triangular-, moreover, the configuration may be provided with an 0 ID external shape which has at least one longitudinally extending formation of desired Z_ C shape, such as at least one groove and/or rib. An elongate structural member of tubular C) shape of square or rectangular configuration is commonly known as a "box- section structural member".

Such structural members are widely used in buildinas and the like as bracing elements, for example, as structural ties for roof structures, trusses, stanchions and space frames. Such structural ties may be provided to accommodate wind loading, in which case they are commonly referred to as wind braces.

Such a structural member has hitherto comprised a hot rolled tube provided with an attachment portion at each end. Such structural members made of hot rolled tube have generally been relatively expensive and heavy. They are made by cuttinc, to C> length from a stock length of tube of a diameter and wall thickness which approximates as far as possible to that required for the structural strength. However, because the tube is boug 1 ght in standard sizes, the tube cross-sectional dimensions cannot be tailored for each particular application. In addition, the need to cut to length from a standard length generally leads to a significant amount of waste. In addition, the steps of welding on a cap plate to each end of the tube and a T-piece to provide the attachment portions is required to be performed, followed by shotblasting and painting., I 2 Cold formed elongate structural members have been proposed in EP-A- Z - 0639684 but these proposals have suffered from certain disadvantages relating to the manner of connecting together adjacent edges of the member. In one version the 0 C> C-) structural member comprises a pair of channel shaped components having, at adjacent edges, inwardly directed lips which are connected tog D gether by spot welding or by I fastening arrangements which require access to be gained to the interior of the tubular section from one end thereof In another version, the structural member is made as a one-piece box section element, having, at adjacent edges, out-turned flanges which are connected together by Suitable means. The first alternative suffers from the disadvantage of the necessity to gain access to the interior of the cross-section, whilst Z- the second embodiment suffers from the disadvantage of havino out-turned flanoes 0 1) which are aesthetically unpleasing and can effect an operational disadvanta,(,',e.

An object of the present invention is to provide a structural member whereby the above-mentioned disadvantages are overcome or are reduced.

A further object of the invention is to provide a method of making such a structural member.

According to one aspect of the present invention we provide an elongate structural member comprising an elongate body part of tubular shape of, polygonal cross-section, made of sheet metal which has been cold formed to provide said tubular shape with at least a pair of adjacent edges of the sheet metal beina connected to-ether, wherein said pair of adjacent edges are disposed at or adjacent a corner of the tubular shape at which first and second sides, terminatin-il.; in said adjacent edges, converge to ide a salient angle therebetween and are topther by a first pr 'ectinc, part of provi I oJ I sid f 'de which overlaps said second side and a second projecting part of said a irst si I I I second side which overlaps said first side.

The elongate body part may be a unitary member longitudinally bounded Z.

by said pairs of adjacent edges.

Alternatively, the body pail may comprise a compound member, comprisina two or more components secured together, each component forming part of 11.).7 C the overall cross-section of the body part.

e of said pair of edges is provided on one component, In this case, one ed(-,, and the other edge of said pair of edges is provided on the other component.

0 0 In this alternative there may be at least one further pair of adjacent edges where the sheet metal is connected tooether and tile or each pair of said adjacent edges being disposed at or adjacent a further corner of the tubular shape at which further first and second sides convergue to provide a salient angle therebetween and a further first p 'ecting part of said first further side overlaps said further second side and a further rOJ C, second p Jecting part of said further second side overlaps said further first side.

r0i 1 21 Preferably, each first and second prqjecting pail comprises a plurality of first and second projecting elenlents respectively.

0 Preferably, each first pro. jecting element is disposed alternately relative to each second pr Jecting element.

oJ I " Each first and second pr 'ecting element may be of generally rectangular C9 I C, conficuration comprising a pair of' oenerall parallel sides pr outwardly from 0 I-D Z-) y 01 111 adjacent inner edge parts and terminating in an outer edge pail, which is generally C" perpendicular to each of said sides.

Preferably, said sides, whilst being generally perpendicular to said inner => ID and outer edge pails are inclined thereto to provide a taper whereby the projecting C> 1 elements decrease in width towards the OLiter edge pail.

0 Where the corner is a right-angle, each first projecting part may be formed C-) In through substantially a right-angle.

The first and second projectint-1, pails may be disposed in a recessed portion of the side which the respective prol"ectinu pail overlaps so that the external surface of the p 'ectinor parts lies substantially in the same plain as tile external surface of the r0i I main part of the side which it overlaps.

The body part may be provided with'an attachment portion at each end.

4 The body part may have Upper and lower sides interconnected by first and second transverse sides extendina normally to the respective upper and lower sides over the majority of the length of the body pail, the body part having at least adjacent one end a flattened attachment portion so that in this portion the first and second transverse portions of the respective transverse sides are deformed so as to have two parts lying C.

substantially parallel to and between upper and lower portions of the upper and lower sides.

The flattened portions may lie substantially midway between the upper and lower sides.

At least one attachment portion may comprise portions of the elongate member displaced out of their original cross-section positions into positions adjacent to C> one another and adapted to co-operate with fastening means.

The attachment portion may comprise an upper portion parallel to an upper side of the body part, a lower portion parallel to a lower side of the body part, said upper and lower portions belm', displaced inwardly relative to their associated upper and lower sides and, disposed therebetween, at opposite sides thereof, first and second transverse portions, each comprisim; ail Upper pail and a lower pail disposed generally 0 I-D in face-to-face relationship with each other and with the respective upper and lower portions and the upper pail being connected, at one side, to an Outer edue of the upper portion and being connected, at ail opposite side, to one edge of the lower part and the lower part being connected at its other edge to an outer edge of the lower portion.

C-1 I-n I-:) Said first and second transverse portions may be provided as an part of the first and second transverse sides of the body portion which are progressively deformed to said face-to-face relationship In a transition region disposed between said body part and said attachment pollion.

Alternatively, at least one attachment poi-tion may comprise an attachment component formed separately from said body pail arid fastened thereto.

The attachment portion may be of channel-shape, the limbs of the channel being disposed in side-by-side relationship with two opposed walls of the body part.

The attachment component may be fastened to said body part by fasteners.

Reinforcing means may be provided to reinforce the walls of the body part.

According to another aspect of the invention we provide a method of pidint', I-D rov I - an elongate StrUCtUral member comprising a body part of tubular shape, of polygonal cross-section, comprising the steps of cold forming sheet metal to provide I I said tubular shape and connecting together at least a pair of adjacent edges of the sheet metal and providing a first pr part ofa first side and a second pr ectinc, part of 0 C9 1 21 01 1 11 a second side of said body part, performing said cold forming step so that said pair of I I =1 adjacent edges are disposed at or are adjacent a corner of the tubular shape at which sid first and second sides conven,e to provide a salient angle and forming said first al I -D projecting part to overlap said second side and said second projecting part to overlap said first side.

Said first and second projecting parts may be provided by a rotary punching unit comprising a pair of rotatable punching elements, one of which is provided with a plurality of recesses and the other of which is provided with a plurality of co-operating projecting punches whereby edge portions of the sheet are punched to provide said projecting portions between parts of the sheet which are punched out by the rotary punching unit.

Alternatively, the first and second pro.1'ecting pails may be made by a punching operation in a reciprOCatOry PLI]ICII1'11,11 unit comprising- a first die provided with a plurality of recesses and a second die provided with a plurality of co-operatingg pr jecting punches, said dies being reciprocal towards and away OJ I CI __> V. I I 6 from each other so as to provide said projecting pails between portions of the strip which are punched therefrom by said purichina unit.

The punching operation may be repeated along the lenoth of the strip.

0 => 1,5 The first and second projecting parts may be provided before the sheet metal is cold formed to said hollow shape.

The sheet metal may be formed to said hollow shape by roll form inor. The C' sheet metal may be fed to a pre-PLIJICh unit before being provided with the first and Z- second projecting pails, or being roll formed, whereby desired openings may be C> provided in the sheet metal.

The method may comprise the further step of displacing attachment portions of the member OLIt of their original cross-sectional posi i I itions into positions adjacent to one another.

Means may be provided for co-operation of said pomions with fastening means.

Where the body part has an upper side and a spaced lower side interconnected by first and second transverse sides perpendicular thereto, means may be provided to displace said first and second transverse sides inwardly, at least at one end, to provide the or each attachment portion, with first and second transverse portions disposed between upper and lower transverse portions, the first and second transverse portions comprising respectively Upper and lower transverse pails disposed in face-toface flattened relationship.

The transverse portions may be initially displaced partially inwardly to an intermediate position to redUce the spacim, between said upper and lower portions and C> subsequently pressure may be SLIpphed to said upper and lower portions to reduce their spacing further and cause the transverse porliors that have said upper and lower parts to ID be brought into face-to-face relationship.

Die means may be provided to define the inclination of the upper and lower sides in an intermediate realon between the body paii and the attachment portion.

0 The invention will now be described in more detail by way of example with 7 reference to the accompanyinp, drawin-il;s there' I In.

FIGURE I a diagrammatic side elevation of an apparatus for produci I g I I I Ing a structural member embodying the present Invention, FIGURE 2 is a cross-section on the fine 2-2 of FlUire I showing a rotary punching unit, FIGURE 3 a diagrammatic perspective view of the rotary p, ching unit un I of Figure 2, FIGURE 4 is a fragmentary perspective view showino stock material of sheet metal, FIGURE 5 Is a diagrammatic perspective view showing the material of I - C, Figure 4 after being subjected to a pUnching operation, FIGURE 6 is a cross-section on the line 6-6 of Figure I showing the crosssectional shape of the metal sheet, FIGURE 7 is a section on the line 7-7 of Figure I showing the shape of the Z.

metal sheet, FIGURE 8 is a perspecti?e \iew of a body part of a strUctural element embodyin,,, the invention, FIGURES 9-11 b show exploded views of a structural element embodying C the invention where the structural element comprises a body part and a separate attachment component providing an attachment portion of the structural member, FIGURE 12 is a perspective view of an elongate structural member embodying the invention where the attachment portion is integral with the body portion, C FIGURE 13 Is a plan view showin(i a stage in the production of the C, attachment portion shown in FIOUre I FIGURE 14 is a side elevation showing, a further stage in the method of forming the attachment portion shown In F111.>Ure 12, FIGURE 15 is a perspecti\.,e view showin- a stage In the nianufacture of the structural member shown in Fiaure 12.

0 FIGURE 16 shows a stage in an alternative, reciprocatory punching, manufacturing method arid FIGURE 17 is a perspective view, showing an alternative structural member embodying the invention.

Referring to the drawings, as a first step in the manufacture of a structural member, a coil 10 of sheet metal, In the present example, sheet steel, is decoiled in a decoiler I I and is fed via a loop 12 to a conventional leveller I') comprising a plurality of alternately disposed rolls so that the sheet metal is alternately bent upwardly and downwardly so as to straiOlliteri it. Sheet metal is then fed via a further loop 14 from the leveller 13 to a pair of feed rolls 15 which are driven by a suitable motor, in conventional manner, to feed the strip into a prepuriching unit 16 where one or more desired apertures are punched in the strip which, prior to pUliching,, is of the configuration shown in Figure 4. For example, the steel sheet may be prept-Inched with apertures such as the apertures shown at 17 in Floure 8 or 18 as shown In Fi"LlreS 12 arid 15.

0 -- The prepUnCh unit 16 also CLJtS the decoiled sheet metal to a desired length. The thus severed sheets are theii fed by a blarik conveyor 19 to a pair of entry rolls 20, again, of conventional type arid driven by a suitable motor so as to pinch the sheet material therebetween and to feed it to a rotary PLHIC111111" 1.11111 2 1.

Referrin- now to Fi(Wres 2 arid '), the metal sheet is fed between two pairs of 0 'D rotary punching dies 22, 23). The rotary PLInching dies 22, 2' are drivably by meshing gear wheels 24 arid are carried on rotatable shafts 25 carrying suitable bearinO means, not shown. At least one of the shafls 25 is driven so as to drive the sheet material through the rotary punching unit 2 1.

The dies 22 have a PlUrality of projections 26 disposed CilCLimferentially therearound whilst the dies 23) have a Plurality of recesses 27 which are adapted to coop-erate with the projections 26 so as to PLInCh OLA material fi-oin the metal stock shown in 9 Figure 4 so as to provide, as shown III Figure 5, a first projecting part oil one side I and a second projecting part 32 on a second side 33 of the sheet material. Each projecting part 30, 32 comprises a plurality of projecting elements 34, 3)5 respectively. Each projecting element 35 has sides 36 which project from adjacent inner edge portions 38 respectively and are interconnected at their outer ends by an outer edge part 39. The sides 36 are slightly inclined so that the width of the projecting elements decreases towards tile outer edge part 3 R As can best be seen from FigUre 5, each first projecting element 34 on the first side 31 is longitudinally aligned With a PLInched OLIt part 3)4a on the second side 33 and each second projecting element 5 oil the second side 33) is longitudinally aligned with a punched out part 3)5a on the first side 3) 1 so that the projectim'; elements -3 K oil the first side 3) I are disposed longitudinally alternately relative to tile projecting parts 3) 5 oil the second side 33.

C The sheet material is then fed into a conventional roll former 40 where a plurality of pairs of co-operating rolls form tile flat sheet material to a box section as shown in Figure 6 in conventional manner. The slight angle hereiribefore mentioned of the sides 36 of the projecting elements 34, 35 of tile first and second projecting parts 30, 31 enables these projecting pails to be brOLI(Y1It Into alternative engagement.

0 -7 1) 1 The thus cold formed sheet material is then fed to a clenching device 42 where a plurality of pairs of co-operating rolls 43 clench the pi- cjecting elements together and also form a recess 44 where the projecting parts overlap. If desired, the above described recess 44 may be formed during the roll fornilm, stage In tile roll former 40.

More partiCLIlarly, the projecting elenlent 34 of tile first side 3) 1 is bent through 90' so as to overlap the second side 33), whilst the second projecting elements 35 are bent I - through 90' so as to overlap the first side 3) 1. As a consequence, a rigid joint connecting the adjacent edges of the tLibUlar shape tilLIS formed is effected.

In either case a recess may extend continuously along the member or a plurality of separate recesses may be provided to receive the projecting parts 34, 35 and there being un-recessed pails therebetween If it is desired to provide the structural member with a separately formed attachment component to provide the attachment portion of the member, the sheet section described hereiribefore is cut to the desired length for a body part as best shown in Figure 8. Figures 9-1 la show some alternative forms of separate attachment component at 50. It will be seen that the attachment component shown in Figure 9 is of channel section and can be fixed in position by suitable fasteners en-a-ed in the apertures 17 and the apertures 5 1, the apertures 52 being provided for attachment of the structural member in a desired application.

In Figure 10, two separate generally channel-shaped members are ided, again with fasteners being en-a-ed with the apertures 17 and 5 1. In this provi I I case, only a single fastenim, apemire 522 is provided for connection of the structural member in use.

In FI oures I I a and I I b alternati ve forn-is of attachment component are 1-7 shown which are of a welded C011f)(Wration. The same reference numerals have been 1D used to refer to corresponding pails.

Of course, if desired, the C011fi(ILlration of the attachment component may I be modified as desired and holes 17a shown In the transversely extending sides of the body part B may be used, if desired, alternatively or in addition, depending upon the configuration of the attachment Component.

Referrin-, now to Fi,",>Ures 12-15, an alternative embodiment is illustrated in which the body part B is formed integrally with an attachment portion 55 with an intermediate portion 56 being disposed therebetween.

As best shown in Figure 13 and FI(I)LII-e 15 first and second transverse sides 57, 58 which extend between upper and lower sides 59, 60 oil opposite sides of the tubular shape are acted upon, at 01)[)OSIte ends ofthe rrieniber, by a pair of punches 61, 62 respectively to form transverse portions 57z:58a of the sides 57, 11 58 with an inward depression so that the transverse portions 57a, 58a are deformed inwardly to provide each transverse portion with an upper part 63 and a lower part 64.

The upper and lower transverse pails 63, 66 are interconnected, by virtue of being integral therewith with each other, as shown at 65, and with upper and lower portions 59g, 60a as shown at 66, 67 respectively. The Lipper and lower portions 59a, 60a are displaced inwardly from their or4prially Occupied positions as a result of the deformation abovedescribed. They are then acted upon by further tools, 70, 71 as shown in Fl-ure 14 so as to move them to the position shown in Figure 12 where the attachment portion 55 is flattened and the Upper and lowers portions 59g, 60a and transverse parts 63, 64 are in a face-to-face engagement. The tools 70, 71 have a transverse part 72 which acts upon the portions 59a, 60a, and an inclined part 73 which defines the shape and slope of the intermediate portion 56.

In a modification of the nianUfactUrin(I method, the rotary punching unit C) may be omitted and the edge notching to produce the projecting be C) C, g parts may performed either in the prepunchin.,1; press 16 or by a Suitable hydraulic or mechanical notching apparatus provided on the conveyor 19.

A further alternative is to provide off hile notchim, of the ed,,es of the coil 1. - by use of the apparatus shown in FlU Ure 16 where a coil of sheet material I 10 1 I is 'led in a decoder I I I and fed via a loop 112 through a notching press 113 where uncol I I I => __:1 the sheet material is formed to the confi-Liration described hereinbefore in connection with the rotary punchin"I unit.

I The notched sheet material is then fed via a further loop 114 to a recoller 115 in conventional inanner. TI)e thus notched coil, I 100 may then provide the coil 10 of the apparatus shown in Fi(_;Lire I bUt With the ornission of the rotary punching unit 21.

Finally, in a further alternative Illustrated in Figure 17, where the same C> reference numbers have been used to refer to corresponding parts, the body part B of the tubular member is made of two components. In this embodiment the two components are indicated -,it 200, 201 and are made in the manner described hereinbefore, except that the roll forming opeiation prodUces the components 200, 201 12 to an angle shape instead of a box shape. The two components 200, 201 are then brought together prior to being fed to the clenching device 42 which is differently Z' I= Z-1) IM configured and is conveniently provided off-line so that first and second projecting parts, 30, 32 are again caused to over-he the second side 33 and the first side 31 respectively and, in addition, further similar first and second prejectinor parts 30,32 are provided, as illustrated at 202 whereby the components 200, 201 are securelyioined together. This alternative manner of manufacture is particularly desirable where the structural member is of a relatively large size. It may be used to provide a structural member with an integral attachment pollion or- an attachment portion provided as at least one separate component as described hereiribefore and in connection with the first embodiment.

If desired the sheet inaterial may be roll formed to any desired configuration so long as adjacent edges are connected at a comer, as described Z_P hereiribefore. For example, the material may be cold rolled to form at least one rib or groove in its external surface.

As hereinbefore described, rotary punching and forming enable the structural members to be produced vei)! economically.

The structural meniber niay be provided in any desired application, for example, wind bracing, -able posts oi- corner posts in industrial buildinos, door frarninor for Z-) 1-1) ZD industrial doors, gable rafters,]lead trini, compression trusses, stanchions, vaulted frames, eaves beams and cladding SUPPOrt beams. They may also be provided in portable accommodation units and used as lintels.

It Should be appreciated iliat, by displacing poillons of the member out of its original cross-section to positions adJaceill to one another to provide the attachment portions, sufficient thickness of material can be provided for fastening means, such as bolts to co-operate directly with tile attachment portions. Thus a structural member, according to this aspect of the invention, provides a satisfactory transfer of forces between the or each attachment portion and the rest of tile meniber whilst enabling the member to produce economically. It will be appreciated that the emb.odirnents described hereiribefore do not require access to be,lained to the interior of a section. Structural members embodying the invention overcome the disadvantages discussed hereinbefore in connection with the structural members made previously from hot rolled members, in that they are made from material cut to len,, th, without waste, and avoid the need for extensive welding operations followed by shot blasting and painting since the sections maybe made from galvanised steel and the members are of lighter weight. Inaddition the members avoid the connectina difficulties previously encountered in the proposals Z> for a cold formed member as described hereinbefore.

Although a rectan(YUlar tubular cross-section has been described herein so that the side and resultant projectino pails, or tabs, after clenching, are inclined at 90' C. C> the tubular cross-section may be of other polys',onal shape such as triangular or hexagonal. The smaller the an.(I)le between the sides the less effective is the clenched connection and for this reason particularly a rectan(ILIlar cross-section is preferred.

C> The features disclosed in the foreaoing description, or the accompanying

I=> IM I-> drawings, expressed in then- specific forms or In terms of a means for performing the 0 disclosed function, or a method or process for attaining the disclosed result, or a class or I group of substances or compositions, as appropriate, may, separately or in any combination of such features, be LitiliSed for realisliw the 'n dverse forms thereof I ir. I.- I WARD21/C/GBD

Claims (15)

Claims

1. An elongate structural member comprising an elongate body part of tubular shape of, polygonal cross-section, made of sheet metal which has been cold formed to provide said tubular shape with at least a pair of adjacent edges of the sheet metal being connected together, wherein said pair of adjace nt edges are disposed at or adjacent a comer of the tubular shape at which first and second sides, terminating in said adjacent edges, converge to provide a salient angle therebetween and are joined together with a first projecting part of said first side which overlaps said second side and a second projecting part of said second side which overlaps said first side, the body part having at least one attachment component formed separately from said body part and fastened thereto.

2. A member according to claim I wherein the attachment portion is of channel-shape, the limbs of the channel being disposed in side-by-side relationship with two opposed walls of the body part.

3. A member according to claim 1 or claim 2 wherein the attachment component is fastened to said body part by fasteners.

4. A member according to any of claims I to 3 wherein the elongate body part is a unitary member longitudinally bounded by said pairs of adjacent edges. 25

5. A member according to any of claims 1 to 3 wherein the body part comprises a compound member, comprising two or more components secured together, each component forming part of the overall crosssection of the body part. 30 WARD21/C/GBD

6. A member according to claim 5 wherein one edge of said pair of edges is provided on one component, and the other edge of said pair of edges is provided on the other component.

7. A member according to claim 5 or claim 6 comprising at least one further pair of adjacent edges where the sheet metal is connected together and the or each pair of said adjacent edges being disposed at or adjacent a further comer of the tubular shape at which further first and second sides converge to provide a salient angle therebetween and a further first projecting part of said first further side overlaps said further second side and a flixther second projecting part of said further second side overlaps said further first side.

8. A member according to any one of the preceding claims wherein each first and second projecting part comprises a plurality of first and second projecting elements respectively.

9. A member according to claim 8 wherein first projecting element is disposed alternately relative to each second projecting element.

10. A member according to claim 8 or claim 9 wherein each first and second projecting element is of generally rectangular configuration comprising a pair of generally parallel sides projecting outwardly from adjacent inner edge parts and terminating in an outer edge part, which is generally perpendicular to each of said sides.

11. A member according to claim 10 wherein said sides, whilst generally perpendicular to said inner and outer edge parts are inclined thereto to provide a taper whereby the projecting elements decrease in width towards the outer edge part.

WARD21/C/GBD

12. A member according to any of the preceding claims wherein the comer is a right-angle and each first projecting part is formed through substantially a right-angle.

13. A member according to any one of the preceding claims wherein the first and second projecting parts are disposed in a recessed portion of the side which the respective projecting part overlaps so that the external surface of the projecting parts lies substantially in the same plane as the external surface of the main part of the side which it overlaps.

14. A member according to any one of the preceding claims wherein reinforcing means are provided to reinforce the walls of the body part.

15.An elongate structural member as hereiribefore described with reference to the accompanying drawings.

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