IE83574B1 - Wall Ties - Google Patents

Description

This 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 bodies 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 central or 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 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.

Known wall ties either have the disadvantage of low corrosion resistance or of high material or manufacturing cost. Furthermore, a number of known wall ties can stretch under tension thereby reducing the strength of the finished structure.

According to the invention there is provided a wall tie comprising a middle portion having at least one bent projection therein, end portions either side of the middle portion, the end portions comprising substantially triangular bodies formed towards the middle portion, the triangular bodies having at least one truncated side which forms the free ended termini of the end positions, an elongate straight portion between each end portion and said middle portion, the end and elongate straight portions being insertable into a wall to anchor the wall tie at the corners of the triangular bodies.

Preferably, the wall tie is a wire wall tie.

Preferably, the triangular bodies are substantially opposed on either side of the longitudinal axis of the wall tie.

More preferably, the middle portion is of undulating form and has two bent projections in one direction and one bent projection in the opposite direction.

Preferably, the overall length of the wall tie is between 150mm and 350mm.

Preferably, the diameter of the wire of which the wall tie is formed is between 2mm and 6mm.

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

The overall length of the wall tie may vary between 150mm and 350mm 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 2mm to 6mm.

It has been found that the working of stainless steel wire, necessary to form it with the at least one downwardly extending bent projection in the middle portion and the generally triangular—shaped end bodies, hardens the wire thereby further to resist subsequent buckling under compressive loads.

However, the bends can lead to poor performance through straightening of the bends under tensile loads. The reduction in the severity of bends in the wall ties of the invention results in improved performance whereby the wall tie is less susceptible to straightening under tension.

Accordingly, the thickness of the wire employed in the wall ties of the invention can be reduced to allow a substantial material saving, of as much as 56%, compared with the material required for a double triangle wall tie of the prior art.

According to another aspect of the present invention there is provided a method of forming a wall tie comprising the steps of laying the ends of a length of straight wire over the mandrels, rotating the wire around the mandrels and effecting pressing action on the middle portion of the length of wire to form the at least one bent projection, and forming the ends of the length of wire towards the direction of the middle portion to form substantially triangular bodies separated from the middle portion by an elongate straight portion, the triangular bodies having at least one truncated side which forms the free ended termini of the wire ends.

One embodiment of the invention is diagrammatically illustrated by way of example in the accompanying drawings in which: Figure 1 is a top plan view of a wall tie according to the invention; Figure 2 is a side elevation of the wall tie of Figure 1; and Figure 3 is a planned View of an end portion of the wall tie showing the triangular body embedded in a wall.

Referring to the drawings, a wall tie 1 is formed of stainless steel wire of diameter D of 2.5 mm having a longitudinal axis L—L. The wall tie 1 comprises a middle portion 2, substantially identical integral end portions 3 and 4, and two extended elongate straight portions 7 and 8 disposed between the end portion 3 and the middle portion 2 and the end portion 4 and the middle portion 3 respectively.

The middle portion 2 is shaped in an undulating form to define a wave pattern having a first projection 5 extending in one direction and, second and third projections 6 extending in an opposite direction either side of the first projection 5. The first projection 5 and, second and third projections 6 correspond to the crest and troughs of the wave pattern which extend from the longitudinal axis L—L in an upward and downward direction respectively.

The absence of additional projections in the middle portion 2 ensures that the insulation tie 1 can be inserted between the bricks or other units defining a wall without insertion of a bend between the bricks or other units thereby minimising disruption during wall construction. In addition, the absence of additional bends in the middle portion 2 increases the resistance of the tie 1 to straightening or the like.

The projections 5 and 6 of the middle portion 2 are defined by the following pitches: mm P2 9 mm Referring to Figure 1, the overall length L1 of the finished wall tie 1 is 150mm to 300mm depending on the intended use. The end portions 3 and 4 each comprise a generally triangular bodies 9 and 10 respectively having a width W of about 22 mm and length (considered in the longitudinal direction of the wall tie) Lg of from about 20 mm to 25 mm.

The triangular bodies 9 and 10 are inwardly shaped in the direction of the middle portion 2, lie in a plain perpendicular to the upward and downward projections 5 and 6 respectively and extend in opposing directions on either side of the longitudinal axis L—L of the wall tie 1. The end portions 3 and 4 terminate at a free end of the wire tie 1 disposed on a truncated side 11 of the triangular end bodies 3, 4. The truncated side 11 is oriented generally inward towards the longitudinal axis L—L of the wall tie 1.

As shown in Figure 1, the triangular bodies 9, 10 are oriented in an oppositely facing disposition either side of the wire when viewed in plan.

The inwardly shaped triangular bodies 9 and 10 give the wall tie 1 improved anchorage in the wall 20.

This is shown most clearly in Figure 3. The part of the wall which provides the resistive load to anchor the wall tie 1 in the wall 20 is indicated by the large cross—hatched portion of the wall 20. This large cross—hatched portion which provides the anchoring force for the wall tie 1 is created by the inwardly shaped triangular bodies 9 and 10 and resists the wall tie 1 from being pulled from the wall 20 in the direction of the arrow B. The wall tie 1 is anchored at the corners 9a and 9b, 10a and 10b of the triangular bodies 9 and 10 respectively.

The resistive load is distributed along the arms 9c and 10c of the triangular bodies 9 and 10 respectively.

As a result of the improved anchorage of the wall tie 1, the thickness of the wire employed to form the wall tie 1 can be reduced to allow a substantial material saving, of as much as 56%, compared with the material required for a double triangle wall tie of the prior art.

The reduction in the number of bends in the wall tie 1 of the invention, the presence of one projection 5 and the extended portions 7, 8 facilitate the insertion of the tie 1 in a wall during construction to a maximum extent without any bends being disposed between the bricks or the like employed to construct the wall i.e. the tie 1 does not disrupt the orientation of the bricks and facilitates optimal contact of the bricks etc with the end portions 3, The stainless steel material of which the wall tie 1 is formed preferably has a minimum tensile strength of 460 N/nmz.

It will be appreciated that the tie 1 can be of any suitable material which affords the requisite properties, for example, metallic material and plastics material.

The invention is not limited to the embodiments hereinbefore described which can be varied in construction and detail.

Claims (1)

CLAIMS A wall tie Comprising a middle portion having at least one bent projection therein, end portions either side of the middle portion, the end portions comprising substantially triangular bodies formed towards the middle portion, the triangular bodies having at least one truncated side which forms the free—ended termini of the end—portions, an elongate straight portion between each end portion and said middle portion, the end and elongate straight portions being insertable into a wall to anchor the wall—tie at the corners of the triangular bodies. A wall tie as claimed in Claim 1, wherein the wall tie is a wire wall tie. A wall tie as claimed in
1. Claim 1 or 2, wherein the triangular bodies are substantially opposed on either side of the longitudinal axis of the wall tie. A wall tie as claimed in any preceding claim, wherein the middle portion is of undulating form and has two bent projections in one direction and one bent projection in the ‘ opposite direction. A wall tie as claimed in any preceding claim, wherein the overall length of the wall tie is between 150mm and 350mm. A wall tie as claimed in any of Claims 2 to 5 wherein the diameter of the wire of which the wall tie is formed is between 2mm and 6mm. A method of forming a wall tie comprising the steps of laying the ends of a length of straight wire over mandrels, rotating the wire around the mandrels and effecting a pressing action on the middle portion of the length of wire to form at least one bent projection, and forming the ends of the length of wire towards the direction of the middle portion to form substantially triangular bodies separated from the middle portion by an elongate straight portion, the triangular bodies having at least one truncated side which forms the free—ended termini of the wire ends. A wall tie substantially as hereinbefore described with reference to and as shown in the accompanying drawings. A method of forming a wall tie substantially as hereinbefore described with reference to and as shown in the accompanying drawings.