GB2336859A

GB2336859A - Web member for a structural truss

Info

Publication number: GB2336859A
Application number: GB9909783A
Authority: GB
Inventors: John Tadich
Original assignee: Mitek Holdings Inc
Current assignee: Mitek Holdings Inc
Priority date: 1998-04-30
Filing date: 1999-04-28
Publication date: 1999-11-03
Anticipated expiration: 2019-04-28
Also published as: GB2336859B; GB9909783D0; AUPP326898A0

Abstract

A web member for connecting the top and bottom chords of a structural truss comprises a middle section 30, which may be of channel form, curved wall sections for load bearing 60 and connector plates 40. Tabs 62 may be provided to reinforce the load bearing portion 60. Punched nails 46 project from the connector plates 40 for attaching the web member to the chords. The load bearing portions 60 are shaped for blunt end engagement with the chords without regard to the angle of intersection. The webs may be formed integrally or as separate components (figure 6) and has a width less than one half of the width of the chord to allow arrangement in overlapping configurations.

Description

(i) 2336859 1 STRUCTURAL TRUSS Rackaround of the Invention This invention

relates generally to structural trusses and more particularly to trusses formed by chords and webs interconnecting the chords.

Structural trusses, and particularly those used for supporting the roof of residential structures, have traditionally been made of wood. Typically, the trusses have a bottom chord and top chords which define the. eripheral shape of the truss. These chords are io p strengthened and rigidified by webs extending between t-he bottom chord and respective top chords. The price of wood has risen to the point where other materials such as ste.el become practical as materials for truss is fabrication. A truss fabricated of metal components is shown in coassigned U.S, Patent No. 5,457,927. It is also known to use metal webs in combination with wooden chords, such as shown for flat trusses in coassigned U.S. Patent No. 4,475,328.

Steel truss comzcnents must be formed into shapes which permit their use in place of the traditional wooden components. The simpler and more standard the formation of the components, the greater the savings realized, However, standardization of the com-oonents is made difficult, because trusses come in many different sizes and shapes. The webs extend between the chords in different arrangements, and therefore incersect che chords at different angles - However, the webs must have the ability to be connected to the chords and they must be able to accept loads from the chords regardless of their angle of intersection.

U 2 Summarv of the Invention Among the several objects and features of the present invention may be noted the provision of a cruss which employs metallic components; the provision of such a truss which has components of standard design for use in different configurations; the provision of such a truss which has metal webs capable of use with wooden chords; the provision of such webs which bear loads without regard to their angle of intersection with the io chords they engage; and the provision of such a truss which is economical to manufacture.

Also among the several objects and features of the present invention may be noted the provision of a metal web member which achieves the foregoing objects.

Generally, a truss of the present invention comprises a bottom chord and at least one top chord connected to the bottom chord. Webs are arranged between the bottom chord and the top chord and intersect the top and bottom chords at oblique angles, The webs have load bearing portions at each end thereof engaging the bottom and top chords, The load bearing portions each are shaped for blunt end engagement with its respective chord without regard to the angle of intersection of the web with the chord.

In another aspect to the present invention, a metal web for use in a truss to interconnect a tor) chord with a bottom chcrd of the truss comprises an elongate, generally channel shaped middle section including side vialls and a bottom wall. Load bearing portions at each end of the middle section are capable of engag-ing the bottom and top chords, respectively. The load bearing portions each are shaped for blunt end engagement with a respective chord without regard to the angle of intersection of the web with the chord.

3 other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.

Descriotion of the Drawings Figure 1 is view of a truss embodying the in77ention; FiSure 2 is a plan view of a web used in the truss of Figure 1; Figure 3 is a cross-sectional view along the line iII-III of Figureli Figure 4 is a side view of the web of Figure 2; Figure 5 is a cross-sectional view along the line vv of Pigure 1; Figure 6 is a view of a further embodiment of the invention; and Figure 7 is a plan view of part of the embodiment of Figure 6.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Deser"'Lmtion of the Preferred Embodiments Piqure 1 shows a roof truss 10 which is generally conventional in appearance having a bottom chord 12 and a pair of obliquely arranged top chords!4 and 16. The chords 12,14 and 16 may be coupled together by connector plates having punched teeth projecting from the plateS as is well known, Each plate is pressed or otherwise forced.Lnto adjacent chords so that the teeth penetrate the (typically wooden) chords and thereby join the chords 30 tocether.

The truss 10 has a plurality of webs 20 interconnecting the bottom chord 12 and the top chords 14 and 16, and providing strength and rigidity to the truss. At least some but preferably all of the webs 20 are 0 4 formed from metal and are of the desired length to extend between the bottom chord 12 and top chords 14 and 16 as shown in Figure 1. As is shown in Figure 1, a number of webs 20 of different lengths will be required in order to complete the truss 10.

A web 20 is shown in Figure 2 and comprises a middle section 30 which is of the desired length to span the space between the bottom chord 12 and one of the top chords 14 and 16 at the required location of the web 20.

io Arranged at the ends of the middle section 30 are a pair of connector iDlates 40 which have an outwardly tapering section 42 and a generally wide end 44. The generally wide end 44 has a plurality of teeth 46 punched from the conn.ector plate 40 to form a nail connector plate for is connecting the web 20 between the chords 12 and 14 or 1-6.

The, connector plates are preferably integral with the middle section 30 but could comprise separate parts which are riveted, welded or otherwise attached to the middle section 30 The chords 12, 14 and 16 are formed from wood as is conventional and as is best shown in Figure 3 the central scction 30 is of generally channel shaped cross-section having side walls 50 and 52 and a bottom wall 54. The connector plates 40 are integral with the bottom wall 54 and the side walls 50 and 52 may be formed by folding or bending a flat blank of material to form the central section 30. The middle section 30 has inwardly turned flanges 55 at the free longitudinal edge margins of the walls 50 and 52 in generally opposed relation to the bottom wall 54. The middle section 30 terminates at each end in a generally curved wall section 60 which defines generally semi-circular ends to the central section 30.

The curved wall sections 60.are formed by making a cut, in a lengthwise direction of the web ar the lower part of walls 50 and 52 adjacent connector plates 40. The ends of the walls 50 and 52 cut free from the bottom wall 54 are bent into the curved shape shown in Pigure 2 to form the curved wall sections 60, Thus, the curved wall SCctions 60 are a continuation of the side walls So and 52 at each end of the middle section 30. The curved wall section 60 are shaped for blunt end engagement with the chords 12,14, 16 without regard to the angle of intersection. Thus, the same configuration of the wall section 60 will work for all of the webs 20 in the truss.

P pair of tabs 62 are punched out of the bottom wall 54 adjacent the ends of the curved wall sections 6.0 so as to stand up against the end of the wall section 60 or the inside of the wall sections 60 to strengthen the curved wall sections 60. The tab 62, after being punched frorn the bottom wall 54, leaves slots 63 in the bottom wall 54 is as shown in Figure 2. It is envisioned that additional tabs (not shown) could be provided to engage the curved wall sections 60 and provide more support.

As is apparent from Figures 1 and 5, the web 20 is applied between the chords 12 and 14 by hammering or p---ess,;.ng (in a pressing machine which is not shown) one of the connector plates 40 into the bottom chord 12 and the other connector plate 40 into the top chord 14. Channel shaped middle section 30 is arranged so it is inward of the cerimeter of the chords 12 and 14.

As shown in Figure 5, the curved wall section 60 contacts an upper surface 12a of the chord 12 and enables the web 20 to be angled within the inside angle with respect to the chord 12 for connection between the chords 12 and 14. The other end of the web 20 is connected in the sarne manner. The shape of the connector plates 40, and in particular their width in excess of the v.,idr-h of the middle section 30, assures that a substantial number of teeth 46 will overlie the chord (12,14, or 16) no inatLer what the angle of intersection of the web 20 with the chord. The curved wall section 60 contacts the upper web 11 or 16 so that when the truss is installed and load 1-1 6 is applied to the truss, the curved wall section 60, which is reinforced by one of the tabs 62, takes the load applied to the truss, The wall section 60 and associated tab 62 form a load bearing portion so that the load is directly transmitted from the chords 12 and 14 or 16 into the middle section 30 and no substantial load is taken by the neck portion 69 of the web 20 which fort-ns a transition from the middle section 30 to the connector plates 40.

As shown in Figure 5, the webs 20 have a depth (corresponding generally to the height of the side walls 50, 52) which is less than 50% of the width of the chords 12. The depth of the webs 20 is also less than 50% of the width of the chords 14 and 16. Thus, webs 20 can be arranged in pairs on both sides of the truss between the chords 12,14,16 and also can everlan or cross one another. This increases the number of web arrangements which can be included in the truss and various different web patterns can be utilized therefore increasing the flexibility of the truss design and location and positioning of the webs 20 within the truss 10.

Ficures 6 and 7 show a further embodiment of the invention. in this embodiment, middle section 30 (only one end of which is shown in Figures c and 7) is formed from channel section similar to that in the previous embodiment which has side walls 50 and 52, bottom wall 54 and with inturned flanges 55. The sides walls 52 and 50 have cleats 120 punched from them and which project inwardly frorn the side walls 50 and 52 as shown in Figures 6 and 7 so as to form a space between the cleats 120 and side walls 52 and 50.

In this embodiment of the invention, a separate load bearing member 130 is provided which comprises a generally U-shaped wall member having a rounded end 132 and free ends 134. The free ends 134 are sDaced aoart by a distance slightly less that the distance between the 7 walls 50 and 52 so that free ends 134 can slide into the middle section 30 adjacent the walls so and 52 and into the space between the cleats 120 and the walls 50 and 52, Thus, the cleats 120 effectively couple the load bearing inember 130 to the middle section 30.

The load bearing member 130 functions in the same manner as the load bearing member formed by the curved wall section 60 in the previous embodiment and abuts the upper or lower chords and takes the load applied to the truss in the same manner as described with reference ti Figures 1 to 5 with the load being transmitted to the middle section 20 via the cleats 120.

Connector plates 150 are also formed separate from 'bot h the middle section 30 and load bearing member 130.

is It should be noted that the connector plate 150 is not shown in Figure 7 for ease of illustration. The connector plate 150 has a tongue 152 which slides between walls 50 and 52 and on bottom wall 54 into the central section 30. The tongue 152 may be secured to the middle section 30 by clenching, riveting or any other suitable m.ethcd. Cleats similar to the cleats 120 could also be provided on the bottom wall 54 for receiving the tongue 152.!'he plate 150 has an enlarged portion 154 outwardly of the tongue 154 which carries the punched teeth 160 W1114ch are hammered or pressed into the top and bottom chords of the truss to secure the web shown in Figures 6 and 7 to the truss.

Those skilled in the art will appreciate that the invention described herein is susceptible to variation and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope, C 8

Claims

CLAIMS:

1. A truss comprising: a bottom chord; at least one top chord connected to the bottom chord; webs arranged between the bottom chord and the top chord and intersecting the top and bottom chords at oblique angles, the webs having load bearing portions at each end thereof engaging the bottom and top chords, the load bearing portions each being shaped for blunt end engagement with its respective chord without regard to the angle of intersection of the web with the chord.

2'. A truss according to claim 1, wherein the load bearing portions have a generally smooth curved shape.

3. A truss according to claim 1 or claim 2, wherein the load bearing portions have a generally semicircular shape.

4. A truss according to any one of claims 1 to 3, wherein each web comprises a generally channel shaped middle section including side walls and a bottom wall.

5. A truss according to claim 4, wherein the load bearing portions comprise curved wall sections defined by ends of the side walls formed to extend inwardly over the bottom wall toward each other.

6. A truss according to claim 5, wherein said load bearing portions further comprise means for transferring loads from the curved wall sections to the middle sections of the webs.

\1 9

7. A truss according to claim 6, wherein said load transferring means comprises tabs engaging the curved wall sections and fixedly attached to the web, the tabs being positioned for resisting loads applied to the load bearing portions from the chord engaged by the load bearing portion.

8. A truss according to claim 7, wherein the tabs are formed as one piece with the bottom wall of the web.

9. A truss according to claim 4, wherein the load bearing portions of the web each comprise a wall member insert received in the channel shaped middle section and having a curved surface engaging the chord.

10. A truss according to claim 9, wherein the load bearing portions further comprise means for transferring loads from the wall member inserts to the middle section of each web.

11. A truss according to claim 10, wherein said load transferring means comprises cleats engaging the wall member inserts and fixedly attached to the web, the cleats being positioned for resisting loads applied to the load bearing portions from the chord engaged by the load bearing portion.

12. A truss according to claim 11, wherein the cleats are formed as one piece with the side walls of the middle sections of the webs, the cleats receiving edge margins of the wall member inserts.

13. A truss according to any one of claims 1 to 12, wherein the webs each comprise connector plates located at the ends of the web, the connector plates having a plurality i of punched nails projecting from the connector plate and penetrating the chord engaging by the web end for connecting the web to the chord.

14. A truss according to claim 13, wherein the connector plates are formed separately from the webs, each connector plate including a tongue which is received in the channel shaped middle section of the web.

15. A truss according to any one of claims 1 to 14, wherein the webs and chords have respective thicknesses, the web thickness being less than one half the thickness of the chords whereby webs can be arranged between the chords in overlapping configuration.

16. A metal web for use in a truss to interconnect a top chord with a bottom chord of the truss, the metal web comprising an elongate, generally channel shaped middle section including side walls and a bottom wall, and load bearing portions at each end of the middle section for engaging the bottom and top chords, respectively, the load bearing portions each being shaped for blunt end engagement with a respective chord without regard to the angle of intersection of the web with the chord.

17. A metal web according to claim 16, wherein the load bearing portions have a generally curved shape.

18. A metal web according to claim 16 or claim 17, wherein the load bearing portions have a generally semicircular shape.

19. A metal web according to any one of claims 16 to X 11 18, wherein the load bearing portions comprise curved wall sections defined by ends of the side walls formed to extend inwardly over the bottom wall toward each other.

20. A metal web according to claim 19, wherein the load bearing portions further comprise means for transferring loads from the curved wall sections to the middle section of the web.

21. A metal web according to claim 20, wherein said load transferring means comprises tabs engaging the curved wall sections and fixedly attached to the web, the tabs being positioned for resisting loads applied to the load bearing portions from the chord engaged by the load bearing 15 portion.

22. A metal web according to claim 21, wherein the tabs are formed as one piece with the bottom wall of the web.

23. A metal web according to any one of claims 16 to 18, wherein the load bearing portions of the web each comprise a wall member insert received in the channel shaped middle section and having a curved surface engaging the 25 chord.

24. A metal web according to claim 23, wherein the load bearing portions further comprise means for transferring loads from the wall member inserts to the middle section of the web.

25. A metal web according to claim 24, wherein said load transferring means comprises cleats engaging the wall 12 member inserts and fixedly attached to the web, the cleats being positioned for resisting loads applied to the load bearing portions from the chords engaged by the load bearing portions.

26. A metal web according to claim 25, wherein the cleats are formed as one piece with the side walls of the middle sections of the web, the cleats receiving edge margins of the wall member inserts.

27. A metal web according to any one of claims 16 to 26, further comprising connector plates located at the ends of the web, the connector plates having a plurality of punche d nails projecting from the connector plate for penetrating the chords engaged by the web to connect the web to the chords.

28. A metal web according to claim 27, wherein the connector plates are formed separately from the web, each connector plate including a tongue which is received in the channel shaped middle section of the web.

29. A truss according to claim 1 constructed and arranged substantially as herein described and as illustrated in Figures 1 to 5 or Figures 6 and 7 of the drawings.

30. A metal web according to claim 16 constructed and arranged substantially as herein described and as illustrated in Figures 1 to 5 or Figures 6 and 7 of the drawings.