IE890469L

IE890469L - Wall ties

Info

Publication number: IE890469L
Application number: IE46989A
Authority: IE
Inventors: John Brian Fallon
Original assignee: Yissum Res Dev Co
Priority date: 1988-03-01
Filing date: 1989-02-14
Publication date: 1989-09-01
Also published as: AU3001689A; IE63289B1; GB2215356B; GB8804865D0; GB2215356A

Description

The invention relates to wall ties.

Wall ties are used to tie together spaced apart leaves of cavity masonry walls and have been provided in many forms.

A butterfly tie is formed from a length of wire,' has two triangular shaped members of wire with their apices interlocked and has the two ends of the wire extending downwardly at a mid-position. A double triangle tie is also formed from a length of wire, has a middle straight portion, a triangular shaped loop at each end and a downwardly dipped portion at the centre to cause drips to run off. A vertical twist tie is formed from a single rectangular strip of sheet material with the ends split and splayed and the middle portion twisted axially through 90°. A simple twisted tie is formed as a single rectangular strip of sheet material with several axial twists therein.

The requirements for wall ties are to effect a secure mounting with spaced apart leaves of a wall at the respective ends without providing a bridge across which 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 3 moisture can run from one leaf to the other. They must be corrosion resistant so that they can continue to effect their function for several tens of. years. It has been proposed to form the butterfly and double triangle ties of galvanised low carbon steel wire, copper, copper alloys or an austenitic stainless steel wire. The vertical twist or simple twisted ties have been formed of galvanised low carbon steel strip, copper, copper alloys, or an austenitic stainless steel. All previously proposed wall ties either have the disadvantage of low corrosion resistance or of high material or manufacturing cost.

According to the invention there is provided a stainless sfcaal wire wall tie comprising a middle portion having at least one downwardly bent projection therein and end portions which include a semi-circular section and a straight section, the diameter of the semi-circular section extending substantially perpendicular to the middle portion and the straight section being located at each end of the wire extending from the end of the respective semi-circular section towards the middle portion and perpendicular thereto.

Preferably, the end portions are substantially opposed on either side of the longitudinal axis of the middle portion.

Preferably, each said straight section ends at a position short of the radial centre of the respective semi-circular section.

Preferably, the middle portion is of undulating form and has three projections in one direction and two in the other.

Preferably, the overall length of the wall tie is between 150 and 300 millimetres.

Preferably, the diameter of the wire of which it is formed is between 2 millimetres and 6 millimetres.

Preferably, the wall tie is formed by laying the ends of a length of straight wire over mandrels, rotating the wire around the mandrels through 270° and effecting a pressing action on the middle portion of the length of wire to form the at least one downward projection.

The overall length of the wall tie may vary between 150 and 300 mm depending upon the intended purpose, that is to say dimension of wall and cavity which it is to tie and the diameter of the wire of which it is formed is preferably in the region of 3 to 6 mm.

It has been found that the working of stainless steel wire, necessary to form it with the at least one downwardly extending projection in the middle portion and the generally C-shaped end portions, hardens the wire thereby further to resist subsequent straightening. Forming the wire in the shape of a wall tie of the invention can allow a substantial material saving, of as much as 30%, compared with the material required for a double triangle wall tie of similar size and performance and can be effected by simultaneous forming operations allowing very rapid manufacture.

The wall ties of the invention can be formed by laying the ends of a length of straight wire over mandrel and rotating the wire around the mandrels through 270°. A pressing action on the middle portion of the length of wire forms the at least one downward projection.

One embodiment of the invention is diagrammatically illustrated by way of example in the accompanying drawings in which: Figure 1 is a plan view of a wall tie according to the invention; Figure 2 is an elevation corresponding to Figure 1; and Figure 3 is an enlarged view of the middle portion of Figure 2.

Referring to the drawings, a wall tie 1 is formed of stainless steel wire of diameter D of 4 mm. It comprises a middle portion 2 and substantially identical integral end portions 3 and 4. The middle portion 2 has, as best seen in Figures 2 and 3, three upwardly bent projections 5 and two downwardly bent projections 6. The 4 mm diameter wire is bent to form the projections 5 and 6 at radii: R1 = 3 .3 mm R2 s 7 .3 mm R3 = 11 .3 mm R4 = 8 mm R5 = 12 mm Offsets 0 amount to 5mm and the pitches to are:- P^ » 25 mm P2 = 22.5 mm P3 = 8.25 mm mm •m-m Referring to Figure 1 the overall length of the finished wall tie is 150 to 300 mm depending on the 5 intended use - The end portions 3, 4 each comprise a generally semi-circular section 3a, 4a of width W 40 mm and length (considered in the longitudinal direction of the wall tie) L2 20 mm. Each end portion 3, 4 also has a straight portion 3£, 4b which projects, from the end 10 of the respective semi-circular section 3a, 4a, towards the middle portion 2, generally perpendicular thereto and ends at a spacing S of 4 mm from an imaginary point C which is the radial centre of the semi-circular section 3a, 4a. 15 The stainless steel material of which the wall tie 1 is formed preferably has a minimum tensile strength of 460 N/nm2. The width of the cavity L3 is indicated in Figure 2 but can vary. 1 2 3 4 5 6 7 6 9 XO 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 7

Claims

1. A stainless steel wire wall tie comprising a middle portion having at least one downwardly bent projection therein and end portions which include a semi-circular section and a straight section, the diameter of the semicircular section extending substantially perpendicular to the middle portion and the straight section being located at each end of the wire extending from the end of the respective semi-circular section towards the middle portion and perpendicular thereto.

2. A wall tie as claimed in Claim 1 wherein the end portions are substantially opposed on either side of the longitudinal axis of the middle portion.

3. A wall tie as claimed in any one of the preceding Claims wherein each said straight section ends at a position short of the radial centre of the respective semi-circular section.

4. A wall tie as claimed in any one of the preceding Claims wherein the middle portion" is of undulating froi? and has three projections in, one direction and two in the other.

5. A wall tie as claimed in any one of the preceding Claims in which the overall length of the wall tie is between 150 and 300 millimetres.

6. A wall tie as claimed in any one of the preceding Claims wherein the diameter of the wire of which it is formed is between 2 millimetres and 6 millimetres.

7. A wall tie as claimed in any one of the preceding Claims formed by laying the ends of a length of straight wire over mandrels, rotating the wire around the mandrels through 270* and effecting a pressing action on the middle portion of the length of wire to form the at least one downward projection. 8

8. A wall tie as claimed in Claim 1 substantially as hereinbefore described and illustrated with reference to the accompanying drawings.