GB2251634A

GB2251634A - Cavity wall tie

Info

Publication number: GB2251634A
Application number: GB9126809A
Authority: GB
Inventors: Aidan Mark Thomas Chippendale; Ian Dobson
Original assignee: George Clark
Current assignee: George Clark
Priority date: 1991-01-10
Filing date: 1991-12-18
Publication date: 1992-07-15
Anticipated expiration: 2011-12-18
Also published as: GB9100574D0; GB2251634B; GB9126809D0

Abstract

A wall tie suitable for use in the construction of cavity walls, the wall tie having a general Z-shape and comprising an elongate central portion 16 having two elongate end portions 18, 20 extending from either end thereof, the elongate central portion can include a portion 22 twisted through 90 DEG to act as a drip guide. The wall tie can be pressed from strip material, e.g. stainless steel with generally little scrap material between adjacent blanks. <IMAGE>

Description

"Cavity Wall Tie" The present invention relates to a wall tie suitable for use in the construction of cavity walls.

Existing wall ties include types formed from wire, which require relatively complex bending operations in their manufacture, and fishtail types formed from strips cut from sheet steel, wherein the ends of the strip are required to be split and spread apart. The number of manufacturing steps involved in the production of both bent wire and fishtail types of wall tie has a direct bearing on the cost of the finished ties.

In accordance with the invention there is provided a wall tie formed from sheet material and comprising an elongate central portion having first and second elongate end portions extending from either end thereof at an angle to and in opposite directions away from the central longitudinal axis of the central portion so as to define a generally Z-shaped planar member, the angles between said end portions and said axis being less than or equal to 90 .

Preferably, said angles are greater than 60".

Preferably also, said angles are substantially equal.

Preferably also, said first and second end portions are of substantially equal length.

Preferably also, a twist is formed in said central portion to provide a drip guide, the twist most preferably comprising a portion lying in a plane normal to the plane of the remainder of the tie.

The shape of the basic tie defined above is such that a first edge of one tie will nest against a second edge of a second identical tie, so that the ties may be pressed from strip material with minimal webbing scrap between each tie.

According to a second aspect of the invention, a method of manufacturing wall ties comprises pressing tie blanks of the shape defined above from a continuous strip of sheet material- such that the opposite ends of the blanks are positioned at. or adjacent to opposite lateral edges of the strip and such that the transverse cut edge of the strip left by the pressing of each blank forms one edge of the succeeding blank.

Preferably, the method includes a subsequent step of forming a twist in the central portion of the blank, the twist comprising a portion lying in a plane that is ~normal to the plane of the remainder of the tie.

The ties are preferably formed from stainless steel and may be formed either by separate pressing and twisting tools or by progression tooling stations.

The pressed blanks themselves can be used as ties, although the twisted form is preferred. Accordingly, the invention allows the ties to be manufactured in one or two simple operations with a minimum of scrap material.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic plan view of a strip of sheet steel illustrating the manner in which the tie blanks nest together; and Fig. 2 is a plan view of a wall tie in accordance with the invention.

Referring now to the drawings, a wall tie 10 in accordance with the invention is formed from a blank 12 pressed from a strip 14 of sheet metal (preferably steel). The blank comprises a central portion 16 and first and second end portions 18 and 20 of equal length (B) extending at equal and opposite angles A (see Fig. 2) from either end of the central portion 16.

Relative to the central longitudinal axis of the central portion 14, the angle A is preferably in the range 60 to 900. The blank is of constant width W throughout.

As is best seen in Fig. 1, the shape of the blanks 12 is such that they nest precisely together and can be pressed from the strip 14 with minimal scrap material between adjacent blanks. The blanks are dimensioned and oriented so as to extend across substantially the full width of the strip 14.

The blanks 12 are usable as wall ties as pressed from the strip 14. However, they are preferably provided a 90 twist 22 in their central portions 16 to form a drip guide, as seen in Fig. 2.

The blanks might suitably be formed from strip 200 mm to 250 mm wide (dimension L in Fig. 2) and 2 mm to 5 mm in thickness (T), the width (W) of the blanks being 8 mm to 25 mm and the length (B) of the end portions 18, 20 being 35 mm to 50 mm.

The invention thus provides a wall tie and a method of manufacture thereof involving only one or two operations and minimal scrap material.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

1. A wall tie formed from sheet material and comprising an elongate central portion having first and second elongate end portions extending from either end thereof at an angle to and in opposite directions away from the central longitudinal axis of the central portion so as to define a generally Z-shaped member, the angles between said end portions and said axis being less than or equal to 900.

2. A wall tie as claimed in Claim 1, wherein each of said angles is greater than 60

3. A wall tie as claimed in Claim 1 or 2, wherein said angles are substantially equal.

4. A wall tie as claimed in Claim 1, 2 or 3 wherein said first and second end portions are of substantially equal length.

5. A wall tie as claimed in any one of the preceding Claims, wherein the tie is generally planar with the exception of an out-of-plane area of the central portion.

6. A wall tie as claimed in Claim 5, wherein said out-of-plane area comprises a portion in a plane normal to the plane of the remainder of the tie.

7. A wall tie as claimed in any of the preceding Claims, wherein the shape of the tie is such that a first side edge of one such tie will nest against an opposite side edge of an identical tie.

8. A wall tie as claimed in Claim 1, wherein said sheet material is stainless steel.

9. A method of manufacturing wall ties comprising pressing tie blanks of a general Z shape from a continuous strip of sheet material such that the opposite ends of the blanks are positioned at or adjacent to opposite lateral edges of the strip and such that the transverse cut edge of the strip left by the pressing of each blank forms one edge of the succeeding blank.

10. A method as claimed in Claim 9, including a subsequent step of forming an out of plane area in a central portion of the blank.

11. A method as claimed in Claim 10 wherein said out of plane area comprises a portion lying in a plane normal to the plane of the remainder of the tie.

12. A wall tie substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

13. A method of manufacturing wall ties, substantially as hereinbefore described with reference to the accompanying drawings.