US20080250747A1

US20080250747A1 - T-chord open web joist with adjustable ends

Info

Publication number: US20080250747A1
Application number: US11/786,545
Authority: US
Inventors: Fred E. Johnson; Lorraine B. Gregory
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-12
Filing date: 2007-04-12
Publication date: 2008-10-16

Abstract

The disclosed device is directed towards a truss comprising an upper T-shaped chord. A lower T-shaped chord is coupled to said upper chord. A plurality of web members are coupled to said T-shaped chords. An extension section is coupled to said upper T-shaped chord and said lower T-shaped chord approximate the web. Said extension section is configured to by adjustable by trimming.

Description

BACKGROUND

The present disclosure relates to the field of joist and truss construction. In particularly the disclosure relates to a broad spectrum of joist's or trusses having T-shaped chords with the benefits of adjustable length.
Current joist designs offer different design types and can fall into two general categories, open web truss or closed web joist. Both have disadvantages for the consumer.
One type of conventional open web truss which is used for supporting building floor and roof structures and the like is formed by two parallel wooden chords, such as 2×4 or 2×3 dimensions, or the use of composite lumber such as Laminated Veneer Lumber (LVL), arranged one over the other interconnected by webs of steel or wood. The webs may be attached by gluing or by sheet metal connector plates having tamped teeth protruding out allowing them to embed into the wooden chords. Such a truss is generally manufactured in a factory and transported to a construction site for installation as a component of the building. This type of truss is known in the art of trusses as an open web truss and has the ability to be designed with the chord being oriented either in the flat or wide direction or vertically or the narrow direction. While the truss with the flat lumber suffers from not enough material for strength the vertically assembled truss suffers from too narrow of a nailing surface.
It is also known in the art of joist design to build a solid web joist consisting of two parallel wooden chords connected by a continuous solid web such as plywood or Oriented Strand Board (OSB). Such a joist suffers from having the solid web which doesn't leave any area for utilities such as plumbing, electrical or duct work to pass through them.
There are current designs combining both features of the solid web joist and an open web truss. These combinations are limited in production due to difficulty in manufacturing or to weaknesses due to lumber orientation.
Therefore there is a need for a joist that can combine the strength of a solid web joist with the capabilities of an open web truss and the flexibility of an adjustable length which prior art has not addressed.

SUMMARY

The disclosed device is directed towards a strong open web truss formed from an upper chord and a lower chord that are interconnected by diagonal and/or vertical webs. The chords are T-shape providing strength in the vertical direction and giving a wider nailing surface in the horizontal direction. An extension portion is coupled to the upper chord and lower chord with a self-locking bulbous rabbet proximate the web at each end allowing the length of the truss to be adjusted. Typically the truss is assembled from wooden components.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the truss of the prescribed invention are shown in detail below with reference to attached drawings.

FIG. 1 is a partial elevation view of an exemplary truss.

FIG. 2 illustrates a complete isometric view of an exemplary truss.

FIG. 3 is a perspective view of a T-shaped chord.

FIG. 4 is a cross sectional end view of the T-shaped chord and connection to the end adjustable block using a self-locking bulbous rabbet.

FIG. 5 is an exploded cross sectional view of the self-locking bulbous rabbet in detail.

DETAILED DESCRIPTION

Persons of ordinary skill in the art will realize that the following disclosure is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons having the benefit of this disclosure.
This disclosure describes a truss with T-shaped chords. The T-shaped chord includes a horizontal section connected to a vertical leg section approximate the center of the horizontal section forming a T. The chords will be interconnected by webs connected to the vertical section of the T-shaped chord. The truss includes extension sections at opposite ends of the chords. The extension sections extend beyond the webbing. The extension sections are configured to be adjustable allowing for proper fit upon installation of the truss. The extension sections generally having an I-beam cross sectional shape. Particularities for the adjustable sections are described below in more specific detail.
FIG. 1 illustrates a partial elevation view of an exemplary truss. The truss 10 comprises an upper chord 21 combining a horizontal section 111 with a vertical section 11A and a lower chord 21 combining a horizontal section 11 with a vertical section 11A. In an exemplary embodiment, the upper and lower horizontal sections 11 can be made of solid lumber, such as 2×3 or 2×4 lumber or from composite lumber such as Laminated Veneer Lumber (LVL), GluLam, Laminated Strand Lumber (LSL) other types of composite lumber. The vertical section 11A can be made of thinner lumber such as 1×3 or 1×4 or from the same thickness lumber as the horizontal section 11 is made. The vertical section may be made of solid lumber or composite lumber such as Laminated Veneer Lumber (LVL), GluLam, or Laminated Strand Lumber (LSL) or other types of composite lumber. The upper vertical section 11A is coupled with a strut or web 13 to the lower vertical section 11A. In an exemplary embodiment, the horizontal sections 11 and the vertical sections 11A may be comprised from a single part or from individual parts.
The web members 13 are generally arranged in a Warren or V type truss pattern. In another exemplary embodiment, the webs 13 may be arranged in a fan type arrangement where a vertical web 14 and a diagonal web 13 intersect at the vertical chord section 11A. The web members 13, 14 may be connected to the vertical section of the chord 11A by metal connector plates or by finger type adhesive joints or by some other fashion. The web members 13, 14 may be comprised of solid lumber, composite lumber or by metal, either stamped sheet metal or tubular. It will be appreciated by others in the art that other materials may be used while still embodying the spirit of the present invention.
The adjustable truss 10 is constructed with an adjustable end block 12 at each end having a bulbous tenon 16 machined on the top and bottom edge allowing it to lock itself into the vertical sections 11A. In the exemplary embodiment the truss 10 will have a similar bulbous rabbet 16 machined into the vertical sections at the extension to accept the adjustable end block 12. The connection between the adjustable end block will be accomplished with glue. The adjustable end block 12 may be comprised of solid lumber or of composite lumber. The first web 13 may comprise a Bulbous rabbet 16 on one edge to receive a bulbous tenon 17 from one edge of the adjustable end block 12. Those skilled in the art will appreciate that the bulbous tenon 17 and rabbet 16 is a self-locking connection and that it requires no clamping time for gluing, speeding up production time.
FIG. 2 illustrates a complete isometric view of the invention in an exemplary form. In this exemplary embodiment, truss 10 includes an upper chord 21 comprised of a horizontal section 11 with a vertical section 11A and a lower chord 21 comprised of a horizontal section 11 with a vertical section 11A. The upper chord 21 is interconnected to the lower chord 21 by way of webs 13, 14 configured in a v-shape configuration with multiple spans. An opening 15 approximate the center of the span can be used to facility additional space needed for placement of plumbing or duct work. The opening 15 can be facilitated by a web 14 placed vertically at each end of the opening 15. In another alternative exemplary truss, the web 14 maybe placed at the beginning of the webs 13 and the adjustable end block 12. In this alternative embodiment the vertical web 14 may also include a bulbous rabbet 16 to receive the bulbous tenon 17. It will be appreciated by others skilled in the art that other web configurations may be used.
FIG. 3 is an illustration of a perspective view of the T-shaped chord. The T-shape chord 21 will be comprised of a flat horizontal section 11 and a vertical section 11A. In an alternative exemplary form, the T-shaped chord 21 may be comprised of a horizontal section 11 and multiple vertical sections 11A. Those skilled in the art will recognize that the T-shape offers strength in two directions, horizontally and vertically without the waste of using a larger solid piece of lumber and therefore making more efficient use of our timber resources.
FIG. 4 is a cross sectional end view of the connection between the chords 21 and the adjustable end block 12. In the exemplary truss 10 the chords 21 are connected to the adjustable end block 12 with a bulbous rabbet 16 and tenon 17 and facilitated with an adhesive. The vertical section 11A of the chord 21 will have a bulbous rabbet 16 at the end of the truss 10 to accept the bulbous tenon 17 of the adjustable end block 12. An adhesive may be applied between the bulbous rabbet 16 and the bulbous tenon 17.
FIG. 5 illustrates an exploded cross sectional View of the connection between the adjustable end block 12 and the chord 21. The chord 21 comprised of the horizontal section 11 and the vertical section 11A. The vertical section 11A having a bulbous rabbet 16 to accept the bulbous tenon 17. The bulbous tenon 17 comprised of a bulbous end 20 tapers to a narrower neck 18 and a chamfered section 19. Likewise, the bulbous rabbet 16 comprised identically to accept the bulbous tenon 17.

Claims

1. A truss comprising:

An upper chord having a T-shape;

A lower chord having a T-shape coupled to said upper T-shaped chord;

A web coupled to said upper T-shaped chord and said lower T-shaped chord.

An extension section coupled to said upper T-shaped chord and said lower T-shaped chord proximate the web comprising an adjustable end block.

2. The truss assembly of claim 1, wherein said upper chord has a T-shaped cross section comprised of a horizontal section and a vertical section.

3. The truss assembly of claim 1, wherein said lower chord has a T-shaped cross section comprised of a horizontal section and a vertical section.

4. The truss assembly of claim 1, wherein comprising an extension section at each end with an adjustable end block.

5. The T-shaped upper chord of claim 2, wherein said adjustable end block is connected by a bulbous rabbet and tenon.

6. The T-shaped lower chord of claim 3, wherein said adjustable end block is connected by a bulbous rabbet and tenon.

7. The truss adjustable end block of claim 4, wherein said adjustable end block having a bulbous tenon matching the bulbous rabbet of the T-shaped chords.

8. The truss assembly of claim 1, wherein said extension section is configured to be trimmed.

9. The truss assembly of claim 1, wherein said web is connected to an extension section by a bulbous rabbet and tenon.

10. The truss adjustable end block of claim 4, wherein said adjustable end block has a bulbous tenon matching the bulbous rabbet of said web.

11. A method of using a truss comprising;

Providing a first structural support configured to receive the truss and a second structural support configured to receive the truss, the truss comprising an upper T-shaped chord, a lower T-shaped chord, a web coupled to said upper T-shaped chord and said lower T-shaped chord, and a first extension section coupled to said upper T-shaped chord and said lower T-shaped chord proximate said web and a second extension section coupled to said upper T-shaped chord and said lower T-shaped chord opposite first extension section;

Trimming said first extension section to couple with said first structural support;

Trimming said second extension section to couple with said second structural support.