GB2421964A

GB2421964A - Joist hanger for use with I - joists

Info

Publication number: GB2421964A
Application number: GB0506620A
Authority: GB
Inventors: Scott Mcandrew; Luke Richard John Whale
Original assignee: Cullen Building Products Ltd
Current assignee: Cullen Building Products Ltd
Priority date: 2005-01-04
Filing date: 2005-04-01
Publication date: 2006-07-12
Anticipated expiration: 2025-04-01
Also published as: GB0506620D0; GB2421964B; GB0500003D0

Abstract

A hanger for mounting on an I-joist comprises mounting means 6 connectable to the I joist, and support means 8 projecting from the mounting means and defining a support 9 for an orthogonal beam, the mounting means comprising a projection 15 at substantially 90 degrees and adapted for insertion between the upper 3 and lower 4 flanges of the I joist. The mounting means may be face- fixing, top - fixing as shown, or may extend down the back of the I-joist. The projection 15 may have tapered upper and lower edges for ease of insertion, or may have an orthogonal foot which rests on the lower flange of the I-joist. Nail holes 10 may be used for fixing to the I-joist, and further holes 13 may be used to secure the orthogonal beam.

Description

IMPROVED HANGER

This invention relates to an improved hanger for use particularly but not exclusively in connecting together two adjacent members such as I-Joists or connecting a beam to an I-Joist generally at a 90 degree angle and has a particular application in the construction industry.

It is well known within the construction industry that wooden I-Joists are used as a replacement for traditional solid timber beams, and their usage is made all the more popular due to their dimensional stability (no shrinkage, cupping or distortion) and superior load handling capacity (spanning capability) . Wooden I-Joists typically consist of upper and lower rectangular flange members made of either solid or laminated wood, and a central wood-based web member (typically plywood or oriented strand board) glued centrally between these upper and lower flanges into pre-cut grooves. Typically such joists are around 25 cm from flange to flange, the flanges being around 4 cm to 6 cm wide.

The wooden I-Joist is an extremely efficient structural shape but the gap that exists between the central web member and the upper and lower flanges makes it difficult to connect components to them at 90 degrees.

Unfortunately, the need to connect components at 90 degrees is commonplace in domestic house construction, where for example, floor or roof members need to be trimmed around stair or chimney openings. Indeed, almost every example of domestic house construction will require beam connections at 90 degrees to each other.

To form a 90 degree connection to an I-Joist requires the gap between the web and both flanges to be packed or filled with a solid material wood for example, such that a flush surface is created of sufficient area to receive an incoming beam or other structural member. These wood- based packing pieces, provided to facilitate such a 90 degree connection are called "backer blocks".

Where a number of beams need to be Connected to a cross member, known as a "header", at 90 degrees, e.g. where floor beams are trimmed around a stair opening, then multiple backer blocks or a continuous backer block will be required. Metal hangers are then used to connect the incoming beam(s) to the supporting header beam at 90 degrees. These can be either face-fixed directly to the backer block material or top-fixed to the upper flange of the I-Joist where less nails are required into the backer block.

Top fix hangers are generally used for light/medium duty applications as they have limited load-transferring ability but are relatively quick and easy to install.

These hangers have an upper flange which sits on top of the upper surface of the upper flange of the I-Joist in use. Face-fix hangers are tical1y used for higher load application, but are generally more time consuming and expensive to fit. Such hangers have no upper flange sitting on the upper surface of the upper flange of the I-Joist but are attached only on the front face of the joist.

In the case of conventional face-fix connections, multiple nails are provided through the face of the hanger into the backer block. The backer block then transfers the loads imparted by the hanger (from the incoming beam) into the central web of the I-Joist and thereby into the flanges of the I-Joist header.

In the case of the top-fix connection nails are passed through the top and side flanges of the hanger into the upper flange of the header, as well as additional nails being provided through the side flanges into the backer block. As a significant amount of the load from the hanger is being imposed eccentrically onto one side of the header upper flange, the backer block this time helps to prevent the upper flange from rotating as well as transmitting load from the face of the backer block into the central web.

However, backer blocks are rather difficult, time consuming and costly to install in practice. Typical

fixing specifications require backer blocks to be

provided on both sides of an I-Joist web, with 6 long nails being installed from each side with their protruding points folded (clenched) over. Experience has shown that this is one of the most common sources of on site errors when constructing I-Joist floors, due to either incorrect types or numbers of nails being used to fix backer blocks in position.

A number of hangers are disclosed in the prior art. It has been proposed to extend the upper flange of the hanger which sits on the top surface of the I-Joist to surround the rear face of the I-Joist also in order to provide additional stability to the hanger. Whilst these hangers go some way as to address the problems discussed above, there remains room for further improvement of the hangers to support I-Joists and transfer the load carried by such joists.

It is therefore an object of the present invention to provide an improved hanger which overcomes or at least mitigates the problems discussed above.

According to one aspect of the present invention there is provided a hanger adapted for mounting on an I-Joist, the hanger comprising mounting means connectable to the beam, support means projecting outwards from the mounting means and defining a support for an end section of a reinforcement member, I-Joist or other beam, the mounting means comprising a projection provided at substantially 90 degrees to the mounting means and adapted for insertion between the upper and lower flanges of the IJoist.

Advantageousiy the mounting means comprises a metal plate having at least one fixing aperture.

Conveniently the width of the projection is about half the width of the mounting means.

Advantageously the mounting means is provided with a projection on either side of the support means.

Preferably, a fixing aperture is provided on the mounting means substantially at or below the lower edge of the projection.

Advantageously the support means comprises two side walls and a base which project from the mounting means in the form of a stirrup.

Conveniently, the upper and lower edges of the Proj ection are tapered to allow for ease of insertion of the projection between the upper and lower flanges of the I- Joist.

Preferably, at least one of the upper or lower edges of the projection is formed with a foot which extends Substantially perpendicular to the projection such that in use the foot lies along a flange of the I-joist.

One embodiment of the present invention will now be described with reference to and as show in the accompanying drawings in which: Figure 1 is a perspective view of a joist hanger according to one aspect of the present invention; Figure 2 is a schematic side view of the joist hanger of figure 1; Figure 3 is a schematic side view of a joist hanger according to a second embodiment of the present invention; Figure 4 is a perspective view of a third embodiment of the present invention; Figures 5a-5d are side views of alternative fixing methods for use with joist hangers according to the present invention; Figure 6 is a perspective view of the joist hanger of figure 1 with an additional fixing means; Figure 7 is a side view of the joist hanger of figure 6; Figure 8a shows the effect of wood splitting with conventional joist hangers; Figure 8b shows one advantage of the present invention in Preventing wood splitting, and Figure 9 shows a perspective view of a further embodiment of the present invention.

Turning now to Figure 1, there is shown an embodiment of the present invention showing a hanger 1 for use in connecting a beam (not shown) to an I-Joist 2 at substantially 90 degrees. The I-Joist comprises upper and lower flanges 3,4 connected by a central web 5 as described above.

The hanger 1 comprises a mounting plate 6 which is adapted to be mounted on the front face 7 of the upper and lower flanges of the I-joist and a Ushaped support member 8 which projects outwards from the mounting plate for Supporting a beam or other load carrying member.

The mounting plate 6 is substantially rectangular in form and extends from the top edge of the upper flange of the I-Joist to the bottom edge of the lower flange. A return flange 9 may be provided on the upper edge of the mounting plate, as shown in figure 1, in which the top edge of the mounting plate is folded through 90 degrees to lie along the top surface of the upper flange 3 of the I-Joist.

Apertures io are provided in the mounting plate for receiving fixing means (not shown) such as nails or screws for fixing the mounting plate to the front face of the I-Joist against the upper and lower flanges thereof.

The support member 8 is formed of two side walls 9 connected together at the lower end by a base member 10.

The side walls have a first lower region ii which in use is located adjacent the lower flange 4 of the I-Joist, in which the walls 9 have a substantially uniform width and a second upper region 12 in which the thickness of the walls 9 reduces from the end adjacent to the base member towards the end of the walls 9 remote therefrom.

Apertures 13 are provided in the side walls 9 towards the upper edge of the walls to receive fixing means (not shown) such as nails or screws as will be described further below.

The central region 14 of the mounting member adjacent the side walls of the support member is folded through substantially 90 degrees towards the side of the hanger remote from the support 8 means to form a rib 15 which, when the hanger is mounted on a joist 2 as shown in Figure 1, extends towards the central web 5 of the I- Joist as will be described further below. The width of the rib 15 is approximately half of the width of the mounting member 6. The length of the rib 15 is selected to be substantially the same as the distance between the upper and lower flanges 3,4 of the I-Joist to which the hanger is intended to be mounted. Whilst only a single rib is shown in the drawings, a similar rib may be provided on each side of the hanger.

When it is required to join a beam at 90 degrees to an I- Joist, a hanger 1 according to one aspect of the present invention is mounted to the front face of the I-Joist 2, the upper edge of the mounting means 6 being placed against the upper flange 3 of the I-Joist and the lower edge of the mounting means being placed against the lower flange 4 of the I-Joist. Fixing means (not shown) such as nails are introduced through the apertures io in the mounting member and extend into the upper and lower flanges of the I-Joist. The stiffening rib 15 lies between the upper and lower flanges 3,4 of the I-Joist 2.

A beam (not shown) is then introduced into the support member 8 of the hanger 1 and fixing means (not shown) such as nails are introduced through the apertures 13 in the side walls 9 of the support member 8 and into the beam.

The stiffening ribs 15 of the hanger have the effect of assisting in preventing the top flange 3 of the I-Joist 2 from rotating when loads are applied to the hanger 1 and thereby considerably enhances the load carrying capacity of the connection.

In one embodiment of the invention as shown in Figure 3, the upper and lower edges 16 of the stiffening rib 15 is tapered away from the mounting member 6 slightly to ensure that the stiffening rib 15 bites into the bottom edge of the top flange 3 of the I-Joist and the top edge of the bottom flange 4 as the hanger 1 is pushed onto the front face of the IJoist 2.

This tight fit ensures that the stiffening rib 15 engages with the top and bottom flanges 3,4 of the I-Joist immediately and thereby transfers load between them equally.

The rib 15 transfers rotational forces imposed on the top flange 3 of the I-Joist to the bottom flange 4 of the I- Joist thereby sharing the force between the two flanges instead of this being carried by the top flange alone.

Furthermore, the stiffening rib 15 stiffens the metal comprising the mounting means 6 of the hanger which assists in preventing the mounting means which abuts the face of the I-Joist from buckling.

The stiffening rib 15 as described above can be used to create I-Joist connections which do not need backer blocks fixed to the I-Joist web 5 to prevent the top flange 3 of the I-Joist from rotating. The hanger of the present invention has all of the advantages of currently available hangers but with increased load capacity over such hangers.

The increased efficiency in dealing with rotational forces on the I-Joist flanges 3,4 also means that a hanger according to the present invention can be adapted for use in face-fix or top-fix operations. An embodiment of the present invention incorporated into a face fix hanger is shown in Figure 4. The stiffening rib 15 of the hanger effectively resists this rotation as a backer block would do thus enabling either face fix or top fix or wrap around hangers to be used for I-Joist connections without the need for backer blocks.

Figure 5 illustrates different embodiments of the present invention providing face-fix, top-fix, or wrap around hangers which can be used with conventional I-Joists without the need f or backer blocks. The load carrying capacity of each of these embodiments of the present invention is increased with respect to known hangers which are not provided with the stiffening rib 15 as described.

A further improvement in the hangers of the present invention is shown in Figure 6. In this embodiment a further aperture 17 is provided in the mounting plate 6 of the hanger for an additional nail 18 to be placed through the mounting means and into the lower flange 4 of the I-Joist. The aperture 17 is provided adjacent to the bottom corner of the stiffening rib 15 adjacent the mounting means. When the additional nail is inserted into the I-Joist, this serves as a metal bearing for the edge of the stiffening rib 15 as it tries to push into the edge of the I-Joist bottom flange 4.

Such a nail inserted immediately below the lower edge of the stiffening rib 15 as shown in Figure 7 spreads the compression forces over a greater area and prevents the stiffening rib from biting into the top surface of the bottom flange 4 of the I-Joist so easily and quickly.

This enhances the load-carrying capacity of the connection even further.

It will of course be appreciated that ordinarily a nail driven through an I-Joist flange 3,4 at this position would split the solid timber of laminated timber forming the I-Joist flange as shown in Figure 8a, however because the stiffening rib 15 is provided immediately above the top of the I-Joist bottom flange 4, and in tight contact with it, the stiffening rib 15 serves to prevent the top fibres of the flange from lifting upwards and therefore no Splitting Occurs as shown in figure 8b.

A further embodiment of the invention is shown in figure 9 wherein one or both ends of the stiffening rib 15 is formed with a foot 19 which projects outwardly at substantially 900 from the stiffening rib. When the hanger is mounted on an I-joist, the foot lies along the top surface of the bottom flange and prevents the extreme edge of the stiffening rib from bedding into the flanges of the I-joist as soon as the hanger is applied to the I- joist. Additional fixing means (not shown) such as a nail may be used to further secure the foot of the stiffening rib in position on the I-joist flange.

It will be appreciated that the features of the present invention result in a hanger which has an increased load bearing ability without the need for additional backer blocks used to pack out the I-Joist and this in turn provides a more cost effective connection.

Claims

1. A hanger adapted for mounting on an I-Joist, the hanger comprising mounting means connectable to the I- Joist support means Projecting outwards from the mounting means and defining a support for an end section of a reinforcement member, I-Joist or other beam, the mounting means comprising a projection provided at substantially degrees to the mounting means and adapted for insertion between upper and lower flanges of the I-Joist.

2. A hanger as claimed in claim 1 wherein the mounting means comprises a metal plate having at least one fixing aperture.

3. A hanger as claimed in claim 1 or claim 2 wherein the width of the projection is about half the width of the mounting means.

4. A hanger as claimed in any preceding claim wherein the mounting means is provided with a projection on either side of the support means.

5. A hanger as claimed in any of claims 2 to 4 wherein the fixing aperture is provided on the mounting means substantially at or below the lower edge of the projection.

6. A hanger as claimed in any preceding claim wherein the support means comprises two side walls and a base which project from the mounting means in the form of a stirrup.

7. A hanger as claimed in any preceding claim wherein at least one edge of the projection is tapered.

8. A hanger as claimed in any preceding claim wherein at least one edge of the projection is formed with a foot which extends substantially perpendicular to the projection such that in use the foot lies along a flange of the I-Joist.