GB2262560A

GB2262560A - Wall ties

Info

Publication number: GB2262560A
Application number: GB9127005A
Authority: GB
Inventors: Keith Knight; Steven Mullineaux
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-12-19
Filing date: 1991-12-19
Publication date: 1993-06-23
Anticipated expiration: 2011-12-19
Also published as: GB9127005D0; GB2262560B

Abstract

The wall tie comprises a length of stainless steel rod (1) drawn into three parallel flanges (2) which taper from their bases (3) to their outer ends (4). The axes (5) of the flanges are evenly spaced at 120 DEG to each other. The flange rod (1) is twisted so that the flanges form helical fluted ribs providing a rigid structure around the core (6) indicated in dotted line. The three flanges (2) are so spaced from one another that no two flanges lie in a common plane and do not cause a splitting of the brick or masonry into which it is hammered. A three part support for use in inserting the wall tie by means of a hammer drill and having a set of different length cavity spacers to accommodate different length wall ties is also described. <IMAGE>

Description

WALL TIES This invention relates to fixings and more particularly to an improved wall tie which is structurally rigid and reduces the risk of splitting the materials into which the tie is driven and will be able to bear higher loads in tension and compression.

Wall ties are used principally for repairing and reinforcing defective walls. These ties are preferably made of a stainless steel which has a high resistance to corrosion and which keys cavity walls to prevent movement of the walls under strong wind loads while allowing natural expansion and contraction of the wall materials without causing stress.

Wall ties are known which have helical flanges arranged opposite one another in one plane with the disadvantage that when hammered into a wall of brick or other construction material, the opposed flanges cut in the same plane which can cause a splitting of the construction material. The extended pitch of the multiple flanges, e.g. two, reuire the tie to be driven into the wall to a greater depth to obtain a reliable key between the tie and wall.

An aim of the present invention is to overcome these disadvantages and provide a wall tie which has an odd number of flanges which are evenly spaced around the tie.

According to the present invention there is provided a wall tie comprising a length of wire which is drawn into three parallel flanges which taper from their base to their outer ends and are twisted to form a self tapping helically fluted rod.

Conveniently, the wall tie is made of 304 stainless steel.

The wall tie may be made in different lengths and diameters and may be colour coded to identify the different sizes.

According to another aspect of the present invention the wall tie is used with a support made in three parts comprising a spacer rod with an externally screw-threaded spigot with a screw threaded hole in one end, a cavity spacer having a screw-threaded spigot at one end and a support sleeve with an internal screwthread for connection to the spacer rod.

In a preferred arrangement the cavity spacer with the screw-threaded spigot may be one of a set of parts of different lengths.

These parts may be colour coded to identify the different sizes.

An embodiment of a wall tie, according to the present invention, will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is an enlarged fragmentary side elevation of a wall tie; Fig. 2 is a cross-section of the wall tie taken along the line 2-2 of Fig. 1; Fig. 3 is a further enlarged end view of the wall tie shown in Figs. 1 and 2; Fig. 4 is an exploded fragmentary axial section of a wall tie support for holding the tie during driving into a wall; and Fig. 5 is a side elevation of a set of three different size supports shown in Fig. 4.

The wall tie shown in Figs. 1 to 3 comprises a length of stainless steel rod 1 drawn into three parallel flanges 2 which taper from their bases 3 to their outer ends 4. The axes 5 of the flanges are arranged at 1200 to each other so that they are evenly spaced around the tie. The flanged rod 1 is twisted so that the flanges form helical fluted ribs providing a rigid structure around the core 6 indicated in dotted line in Fig. 3.

The three flanges 2 are so spaced from one another that no two flanges lie in a common plane and do not cause a splitting of the brick or masonry into which it is hammered.

The length of the wall tie can be cut from the continuous extruded wire rod to selected predetermined lengths i.e. a standard range 155 mm, 170 mm, 180 mm, 195 mm, 205 mm, 230 mm, 245 mm and 270 mm, with a ground point to make flanges self tapping.

Example 1 The two flanges 2 extend along a self tapering helix of 300.

Wall tie diameter x constant of 2.5 = thread pitch 0 6 mm x 2.5 = 15 mm.

Example 2 The three flanges 2 extend along a thread pitch at 300.

Wall tie diameter x constant of 1.6ras = thread pitch 8 6 mm x 1.6r8 = 10 mm.

In known tie rods having two flanges the tie rod has to be driven into the wall at least one thread pitch length which could be a minimum of 15 mm. In the improved wall tie the three flange tie has only to be driven a pitch of 10 mm because the thread pitch 13 reduced by a third before it starts to provide a reliable key between the wall tie and wall and reduces the length of tie required. This also facilitates the time taken to fit the wall tie and the length of wall tie with the consequential reduction in cost.

The length of wall tie is selected from the standard range to suit the thickness of the walls to be tied and the cavity between them. The wall tie is driven into the wall using a hammer drill with the interposition of a tie support having an axial hole in which one end of the wall tie is inserted and the other end is held in the drill chuck.

The support is made from a tempered steel comprising a spacer rod 7 with a left hand screw-threaded spigot 8 having an axial right hand screw-threaded hole 9 at one end and a series of four radially spaced slots 10 at the opposite end to facilitate it to be gripped in the chuck of a hammer drill. A metal sleeve 11 has an internal left hand thread 12 at one end and a drilled hole 13 at the opposite end. The spacer rod 7 and the sleeve 11 are screwed together with the interposition of a cavity spacer 14 with a right hand screw-threaded spigot 15 which screws into the threaded hole 9 of the spacer rod 7.

The threaded spigot 8 together with the cavity spacer 14 are located in the sleeve 11 and the threaded spigot 8 screws into the internal screw-threaded end 12 of the sleeve 11. Holes are provided in the three parts to facilitate tightening of the parts when they are threaded together.

The present invention provides a set of different length cavity spacers 14 as shown in Fig. 5.

Depending on the length and diameter of the wall tie, an appropriate length and diameter cavity spacer 14 is selected and screwed into the spacer rod 7. The different length of the cavity spacer extends into the sleeve varying the length of hole in the sleeve, for different length wall ties.

It will be appreciated that instead of having to provide complete supports of different lengths for different wall ties, the spacer rod 7 and sleeve 11 are standard while the cavity spacers from the set need only be replaced depending upon the length of wall tie used, providing a consequent saving in the cost of materials.

The installation of the wall tie is as follows: A clearance hole is drilled in the outer wall of two cavity walls to be tied slightly larger than the outside diameter of the metal sleeve 11. The length and diameter of wall tie is selected to bridge the walls and penetrate the inner wall or a pilot hole in the inner wall to a depth which will take a load of IKN.

The correct length and diameter of cavity spacer 14 is selected and screwed into the spacer rod 7. The cavity spacer is then located into the sleeve 11 and the spacer rod screwed into the threaded portion of the sleeve in an anti-clockwise direction so that it does not unscrew when the wall tie is rotated. The free end of the spacer rod 7 is locked in the chuck of a hammer drill (not shown) gripping the radial slots 10. A wall tie of the appropriate length is placed in the sleeve 11 and hammered into the inner cavity wall. When the join between the sleeve and spacer rod reaches the outside surface of the outer cavity wall, the wall tie has been driven the correct depth into the inner wall. The diameter of the pilot hole allows the wall tie to rotate so that the three helical flanges rotate similar to a screw thread keying the leading end of the wall tie into the inner cavity wall.

The support 7 and hammer drill are removed leaving the wall tie between the cavity walls. The clearance hole surrounding the tie in the outer cavity wall is filled with a polyester resin using a resin cartridge and when filled the outside resin is smoothed to a neat finish.

The wall tie according to the invention penetrates into materials having varying densities e.g. a hammered tie struck into low density material such as soft brick, aircrete, timber and mortar. When hammered through higher density materials such as hard brick, concrete or hard timbers a pilot hole is first drilled.

It will be appreciated that various modifications may be made to the wall tie for example the ends of the cut lengths of rod may be marked with coloured markings to identify different lengths and diameters of wall tie. Similarly the set of supports can also be colour marked to identify them.

Although the example is given of a wall tie connecting two cavity walls the fixing may be used to connect other building structures, such as wooden joists or other wooden battens together or to an adjoining wall structure.

Claims

CLAIMS:

1. A structural fixing comprising a length of wire which is drawn into at least three parallel flanges which taper from their base to their outer ends and are twisted to form a self-tapping helically fluted rod.

2. A structural fixing as claimed in Claim 1, wherein it is made of 304/316 stainless steel.

3. A structural fixing as claimed in Claim 1 or 2, wherein it is made in different lengths and diameters which are colour coded to identify the different sizes.

4. A structural fixing as claimed in any preceding claim, wherein it is in the form of a wall tie.

5. A support for use with the structural fixing as claimed in any preceding claim, wherein it is made in three parts comprising a spacer rod with an externally screw-threaded spigot with a screw-threaded hole in one end, a cavity spacer having a screw-threaded spigot at one end and a support sleeve with an internal screwthread for connection to the spacer rod.

6. A support as claimed in Claim 5, wherein the cavity spacer is one of a set having different lengths to accommodate different length structural fixings.

7. A support as claimed in Claims 5 or 6, wherein the three parts are colour coded to identify different sizes.

8. A structural fixing substantially as herein described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

9. A support substantially as herein described with reference to and as shown in Figures 4 and 5 of the accompanying drawings.

10. Each and every novel feature or novel combination of features herein disclosed.