GB1573113A

GB1573113A - Timber trusses

Info

Publication number: GB1573113A
Application number: GB48552/76A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-11-22
Filing date: 1976-11-22
Publication date: 1980-08-13
Also published as: ATA10477A; AT347090B; LU76518A1; NL7700085A; AU514441B2; AU2111077A; CH609744A5; DE2700399A1; FR2376930A1; BE850056A

Description

(54) TIMBER TRUSSES (71) We, JAMES KNOWLES and JACK NEVILLE SCHMITT, both citizens of the United States of America, respectively of 1275 Club Drive, Bloomfield Hills, Michigan, United States of America and 1000 Decker Road, Birmingham, Michigan, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to timber trusses.

According to one aspect of the invention there is provided a sheet metal webconnector for interconnecting a pair of parallel, horizontally arranged, wooden chord members of roughly rectangular cross-section, i.e., having coplanar opposite side faces and upper and lower faces, for thereby forming a timber truss comprising a substantially flat, stiff, metal sheet formed in a V-shape to provide a flat apex portion and two elongated diverging legs, all in substantially the same plane; and a plurality of pointed fastening teeth struck out and extending normal to the plane of each of said portions for embedding into coplanar sides of said chord members so that the web-connector may be applied against and is located only along a side of chord members, i.e., in a generally vertical plane, and being otherwise free of securement to the inner and outer faces of the chord member.

According to a second aspect of the invention there is provided a timber truss for use in building, comprising two substantially spaced apart wooden chord members and a web-connector as hereinbefore defined which extends between the chord members with its teeth embedded in the chord members.

According to a third aspect of the invention there is provided a timber truss comprising a pair of parallel, horizontally arranged, wooden elongated chord members of roughly rectangular crosssection, i.e., having coplanar opposite side faces, and a web-connector comprising a substantially flat stiff metal sheet formed in a chevron shape to provide a flat apex portion and two elongated diverging legs with enlarged end portions at the ends of said legs opposed from said flat apex portion, said legs, said apex portion and said end portions all being substantially in the same plane;; a plurality of pointed fastening teeth struck out of and extending normal to each of said end portions and said apex portion embedded into coplanar sides of said chord members so that the web-connector is located only along one side of said chord members, i.e., in a generally vertical plane, and being otherwise free of securement to the inner and outer faces of the chord member; and a central integral narrow reinforcing rib formed along the center of each of said diverging legs and extending substantially the full length thereof from said apex to the respective end portion, said rib being approximately V-shaped in cross-section with its apex displaced from the plane of its leg and being substantially aligned with the central axis of its leg.

A timber truss embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a section of the truss which forms a floor or roof deck joist; Figure 2 is an enlarged, fragmentary, cross-sectional view of the truss of Figure 1 showing one chord and attached webconnectors; Figure 3 is an enlarged elevational view of a single web-connector; Figure 4 is a side elevational view of the web-connector; Figure 5 is a cross-sectional view taken in the direction of arrows 5-5 of one webconnector; Figure 6 is a cross-sectional view taken in the direction of arrows 6-6 of Figure 3 of the apex connector portion of the webconnector; Figure 7 illustrates the nesting relationship of the web-connectors as they are formed into blanks from a sheet of metal;; Figure 8 is a partial front elevation of a truss with the upper chord and web plate bearing on a columnar support; Figure 9 is a partial cross-section as seen in the plane of arrows 9-9 of Figure 8; Figure 10 is a partial front elevation of a truss with the lower chord and web plate bearing on a columnar support; and Figure 11 is a partial cross-section as seen in the plane of arrows 11-11 of Figure 10.

Referring to the drawings, Figure 1 illustrates a section of a timber truss or joist formed of a pair of vertically spaced apart wooden chord members 11 which may be of conventional 2" x 4" lumber. The chords are interconnected by diagonally arranged web-connectors formed of sheet metal. Such metal web-connectors 12 are made in a chevron or V-shape to provide legs 13, an apex connector portion 14 and leg connector portions 15. The connector portions 14 and 15 are provided with struck-out spikes or teeth 16 for embedding into the chord members.

The edges of the legs 13 are bent to form a continuous inner (as considered in use) flange 17 which extends substantially the full length of each leg and continues around the arc forming the apex between the legs, and an outer (as considered in use) flange 18.

A channel or groove 19 is formed along the length of each leg 13 by bending or impressing for rigidifying the legs 13 in conjunction with the flanges 17 and 18.

There are locating holes 65 through each leg 13 for holding the web-connector in apparatus for forming timber trusses, which apparatus has upstanding pegs.

As shown in Figure 7, the webconnectors may be formed by starting with an elongated sheet of metal, such as suitable sheet steel of adequate strength and then blanks 12a may be stamped or slit from the sheet. These blanks are in effect, nested, one within the other. To form the complete web-connectors, the blanks are first, partially lanced; second, formed or flanged; third, teeth punched; and last, finally cut off the sheet, while the sheet passes through a progressive die. Thus, as can be seen, in the manufacturing process for forming the web-connectors, there is a minimum of waste material, which obviously reduces the overall cost of manufacture.

The size, i.e., the height of the webconnectors may be varied in the manufacturing process by using stamping dies which have fixed inserts for the connector portions and teeth and removable legforming portions which can be interchanged with other leg-forming portions to make the legs longer or shorter, as desired.

Thus, the die expense, due to the configuration of the web-connector, is substantially reduced.

As can be seen in Figures 1 and 2, the web-connectors are applied in pairs, one on each vertical face of the aligned chord members, and their teeth are embedded only into the side faces of the chord members. This permits forming the truss by laying one web-connector down upon a horizontal surface, with its teeth upwardly, laying the chord members above it and then placing the second or opposing webconnector upon the exposed upper surface of the chords, teeth down, so that a single compression or clamping operation at each overlapped connector portion can cause the teeth thereof to move into the wood from opposite sides. Thus, the assembly of the web-connectors to the wood chord members is simplified to a considerable extent.

With the specific design of the webconnector, edge flanges, apex arrangement, etc., the loads applied upon the truss place one leg of each web-connector in compression and the other leg in tension, with the resulting force component longitudinal of each chord member. The net result is balancing or approximate cancellation of vertical force components, and absorption of longitudinal force components, as well as resistance against torque or twisting forces. Hence, a good, strong truss is provided using minimal materials.

Referring now to Figures 8-11 the utilization of the truss of the present invention will be explained. Figures 8 and 9 illustrate a first embodiment of a truss having upper and lower chords 11, 11' interconnected by a web-connector 12. The end plate 15 is offset inwardly from the end 25 of the upper chord 11 approximately two and a half inches. The upper chord bears on a stud or beam 26, preferably of wood, which in turn bears on a support 27. Support 27 is illustrated as a brick wall but may be any type of support wall, beam, or stud, etc. The end 28 of the end connector plate 15 overlaps the stud 26 by approximately one inch.

By providing this overlap of the end plate 15, the load bears directly from the web-connector plate into the stud 26 and then to the support column. This substantially reduces the shearing forces and shear stress on the upper chord 11.

As illustrated in Figures 10 and 11, the concept of overlapping the end plate to bear on a support column may be employed on the bottom chord. Figures 10 and 11 illustrate such a construction with the end 30 of the connector end plate 15 overlapping a beam or stud 26 so that the load bears on the support column 27 and shear is reduced in the lower chord 111. A cross strut 31 may be used to interconnect chords 11 and 111.

WHAT WE CLAIM IS: 1. A sheet metal web-connector for interconnecting a pair of parallel, horizontally arranged, wooden chord members of roughly rectangular crosssection, i.e., having coplanar opposite side faces and upper and lower faces, for thereby forming a timber truss, comprising a substantially flat, stiff, metal sheet formed in a V-shape to provide a flat apex portion and two elongated diverging legs all in substantially the same plane; and a plurality of pointed fastening teeth struck out and extending normal to the plane of each of said portions for embedding into coplanar sides of said chord members so that the web-connector may be applied against and is located only along a side of chord members, i.e., in a generally vertical plane, and being otherwise free of securement to the inner and outer faces of the chord member.

2. A sheet metal web-connector according to claim 1, each leg having enlarged end portions.

3. A sheet metal web-connector according to claim 1 or claim 2, in which the opposite edges of each of said legs are formed with roughly parallel, integral, continuous, narrow edge flanges extending substantially the full lengths thereof.

4. A web-connector according to claim 3, the inner edge defining the apex being rounded, and the leg flanges on the inner edges of the legs continuing around the rounded apex edge to form a continuous flange.

5. A web-connector according to claim 3 or claim 4, and including a central integral, bent, narrow rib formed along the center of each leg, and extending substantially the full length thereof; said rib being approximately V-shaped in cross-section with its apex displaced from the plane of its leg and being substantially aligned with the central axis of its leg.

6. A web-connector according to any of claims 3 to 5, with said narrow edge flanges extending normally to the plane of said end portions.

7. A web-connector according to any of claims 3 to 6, said narrow edge flanges extending from the same side of said sheet as said struck out teeth.

8. A timber truss for use in building, comprising two substantially spaced apart wooden chord members and a webconnector according to any preceding claim which extends between the chord members with its teeth embedded in the chord members.

9. A truss according to claim 8, wherein one of the enlarged end portions is offset laterally inwardly from the end of one of the chord members.

10. A truss according to claim 9, wherein the end of said one of said chord members extends laterally beyond the end of the other of said chord members.

11. A timber truss comprising a pair of parallel, horizontally arranged, wooden elongated chord members of roughly rectangular cross-section, i.e., having coplanar opposite side faces and upper and lower faces, and a web-connector comprising a substantially flat stiff metal sheet formed in a chevron shape to provide a flat apex portion and two elongated diverging legs with enlarged end portions at the ends of said legs opposed from said flat apex portion, said legs, said apex portion and said end portions all being substantially in the same plane;; a plurality of pointed fastening teeth struck out of and extending normal to each of said end portions and said apex portion embedded into coplanar sides of said chord members so that the web-connector is located only along one side of said chord members, i.e., in a generally vertical plane, and being otherwise free of securement to the inner and outer faces of the chord member; and a central integral narrow reinforcing rib formed along the center of each of said diverging legs and extending substantially the full length thereof from said apex to the respective end portion, said rib being approximately V-shaped in cross-section with its apex displaced from the plane of its leg and being substantially aligned with the central axis of its leg.

12. A timber truss according to claim 11, comprising: said web-connector enlarged end portions embedded in said first chord member being positioned to laterally overlap a support in use so that shear forces in said first chord member are reduced by said web-connector enlarged end portion

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. wall, beam, or stud, etc. The end 28 of the end connector plate 15 overlaps the stud 26 by approximately one inch. By providing this overlap of the end plate 15, the load bears directly from the web-connector plate into the stud 26 and then to the support column. This substantially reduces the shearing forces and shear stress on the upper chord 11. As illustrated in Figures 10 and 11, the concept of overlapping the end plate to bear on a support column may be employed on the bottom chord. Figures 10 and 11 illustrate such a construction with the end 30 of the connector end plate 15 overlapping a beam or stud 26 so that the load bears on the support column 27 and shear is reduced in the lower chord 111. A cross strut 31 may be used to interconnect chords 11 and 111. WHAT WE CLAIM IS:

1. A sheet metal web-connector for interconnecting a pair of parallel, horizontally arranged, wooden chord members of roughly rectangular crosssection, i.e., having coplanar opposite side faces and upper and lower faces, for thereby forming a timber truss, comprising a substantially flat, stiff, metal sheet formed in a V-shape to provide a flat apex portion and two elongated diverging legs all in substantially the same plane; and a plurality of pointed fastening teeth struck out and extending normal to the plane of each of said portions for embedding into coplanar sides of said chord members so that the web-connector may be applied against and is located only along a side of chord members, i.e., in a generally vertical plane, and being otherwise free of securement to the inner and outer faces of the chord member.

transmitting bearing forces downwardly onto said support.

13. A timber truss according to claim 11 or claim 12, wherein one chord member is positioned so as to be vertically above the other chord member in use of the truss.

14. A timber truss according to claim 13, wherein the one chord member extends outwardly beyond the end of the other chord member.

15. A timber truss according to claims 11 or 12, wherein the one chord member is positioned vertically below the other chord member.

16. A web-connector substantially as herein described with reference to and as shown in the accompanying drawings.

17. A timber truss substantially as described herein with reference to and as shown in the accompanying drawings.