GB2329400A

GB2329400A - Joist Hangers

Info

Publication number: GB2329400A
Application number: GB9719733A
Authority: GB
Inventors: Ronald Charles Sammons
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-09-17
Filing date: 1997-09-17
Publication date: 1999-03-24
Also published as: GB9719733D0

Abstract

A method of forming joist hangers comprises cutting a blank out of a sheet of metal, forming a stirrup having a base (3) and side portions (8,9) by folding upwardly along lines (4,5), and bending the ends of the side portions inwardly along lines (6,7) to form an overlapping double-thickness rear portion (11,12) whose upper end (15,16) is bent over along lines (13,14) to form a masonry flange. The flange may carry indentations and flanges to assist locking when embedded in mortar. The overlapping sheets may be attached together by rivets, welding or soldering. The stirrup portion may include inwardly facing flanges or perforations. The metal used may be galvanised steel or stainless steel, and the sheet may have a thickness between 2mm and 5mm and provide a strength of at least 2.8 Newtons per square millimetre.

Description

JOIST HANGERS This invention relates to an method of making joist hangers and to joist hangers made by the method.

Wooden joists are frequently used in the construction of domestic and other buildings. Such joists extend from walls'to wall inside a building and are supported by the walls. The joist in turn are used to support floorboards, chipboard or similar flooring materials.

The ends of joist may be located in cavities made in the supporting wall or on ledges fixed to the walls. In modern building practice the joist are often carried by metal hangers which are fixed into the supporting walls.

These hangers are substantially "Z" shaped with an upper flange portion, the masonry flange, which lies in the wall and a lower stirrup portion which carries and retains the end of a joist. The hangers are normally fabricated from stainless steel of galvanised steel to avoid rust. The use of joist hangers to support joists has a number of advantages over the earlier practice of locating the ends of joist in a supporting wall. These include a reduction in the length of joists, saving timber, and avoidance of rot in the supporting ends due to damp from the supporting wall.

The use of joist hangers is well known and described in textbooks such as Construction Technology by R. Chudley, Volume I, and The Construction of Buildings by R. Barns.

Various methods have been proposed for fabricating joist hangers. They may be formed from a single strip of metal as described in GB-A-2 249 506 and GB-A-2 282 159 or by cutting and bending metal sheet. The latter method joist hangers from sheet metal involving simple cutting and forming operations giving enhanced strength from comparatively this sheet metal.

According to the present invention there is provided a method of forming joist hangers from sheet material comprising the steps of cutting a blank from a sheet of metal, forming a stirrup having a base portion and side portions by bending the blank upwardly each side of the base and thereafter bending the ends of the side portions inwardly so as the form an overlapping rear portion whose upper end is bent over the form a masonry flange.

There is further a joist hangers having a stirrup portion formed from a single thickness of sheet metal and a masonry flange formed from two overlapping portions of the same sheet of metal to provide a double thickness.

It will be seen that the method provides a joist hanger in which the rear face and masonry flange have a double thickness of metal. This imparts extra strength to the supporting section of the joist hanger.

The masonry flange may carry indentations and flanges in known manner to assist locking when embedded in mortar.

The overlapping sheets of metal forming the masonry flange may be attached together by rivets, welding, soldering or similar fixing means. The stirrup section may also include inwardly facing flanges or perforations for nails or screws so that timber joists may be secured in the stirrup.

The sheet metal used to form the joist hangers may be steel sheet but more preferably a corrosion resistant material such as galvanised sheet or stainless steel sheet.

The thickness may lie in the range 2mm to 5rum. The choice of thickness is dependent upon the required strength which is generally at least 2.8 Newtons per square millimetre.

The joist hangers according to the invention may be formed in a variety of sizes according to the application.

The stirrup width may lie in the range 35mm to 70mm and the drop from the masonry flange may lie in the range 12mm to 20mm.

In order that the invention may be clearly understood it will now be described with reference to the accompanying drawings in which: Figure 1 is a plan view of a blank befcre forming into a joist hanger according to the invention, Figure 2 is a side view of a joist hanker formed from the blank shown in Figure 1, and Figure 3 is a front view of a a joist hanger formed from the blank shown in Figure 1.

A sheet of metal cut as a blank, see figure 1, consists of two side portions 1 and 2 attached to a central portion 3. To form a joist hanger the two side portions 1 and 2 are folded upwardly through a right angle along the fold lines 4 and 5. The vertical portions 1 and 2 are folded inwardly along fold lines 6 and 7 so that portions 1 and 2 overlap. The portions 8 and 9 form the side walls of a stirrup and the portions 11 and 12 form the rear face of the joist hanger.

A final fold is made along the overlapping fold lines 13 and 14 so that end portions 15 and 16 form a masonry flange. Prior to forming the joist hanger or subsequently the end portions 15 and 16 may be punched, bent or otherwise treated to form locking ridges or flanges, Similarly the side walls 8 and 9 may be punched or pierced to form fixings or fixing apertures for the joist to be supported.

Claims

1. A method of forming joist hangers from sheet material comprising the steps of cutting a blank from a sheet of metal, forming a stirrup having a base portion and side portions by bending the blank upwardly each side of the base and thereafter bending the ends of the side portions inwardly so as the form an overlapping rear portion whose upper end is bent over the form a masonry flange.

2. The method as claimed in claim 1, wherein the masonry flange carries indentations and flanges to assist locking when embedded in mortar.

3. The method as claimed in claim 1 or claim 2, wherein the overlapping sheets of metal forming the masonry flange are attached together by rivets, welding, soldering or similar fixing means.

4. The method as claimed in any of the preceding claims, wherein the stirrup section includes inwardly facing flanges or perforations.

5. The method as claimed in any of the preceding claims, wherein the sheet of metal used to form the joist hanger is galvanised steel sheet or stainless steel sheet.

6. The method as claimed in any of the preceding claims, wherein the thickness of the sheet metal lies in the range 2mm to 5mm.

7. The method as claimed in any of the preceding claims, wherein the thickness of the sheet metal provides a strength of at least 2.8 Newtons per square millimetre.

8. Methods of forming joist hangers from sheet material as claimed in claim 1 and as herein described.

9. Methods of forming joist hangers from sheet material as herein described and illustrated with reference to the accompanying drawings.

10. A joist hanger having a stirrup portion formed from a single thickness of sheet metal and a masonry flange formed from two overlapping portions of the same sheet of metal to provide a double thickness.

11. Joist hangers whenever made in accordance with any of the claims 1 to 9.