GB2263291A - A wall tie - Google Patents

Abstract

A wall tie (1) has formations (7, 8) which are made by partly cutting-out disc-shaped portions of a metal strip. Mortar can then engage the remaining aperture and the formation to give very good grip. Because the mortar-engaging formations are between extremities of the tie (1) these may be curved for improved safety. An efficient and versatile production method involves stamping from blank strip in a one-step process. <IMAGE>

Description

"A Wall Tie" The invention relates to wall ties and anchors, hereinafter referred to generally as wall ties.

Many different constructions of wall tie are known and many of these share the common disadvantage that the extremities of the wall tie are designed to grip mortar between the bricks or blocks of a wall. Accordingly, the extremities of presently available wall ties have a shape such as being bifurcated in order to grip the mortar.

Examples of such wall ties are described in British Patent Specification No.s GB 2,052,589 A and GB 2,047,767 A. One problem with this arrangement arises when one leaf of a wall is constructed firstly, leaving the wall ties protruding from the leaf. This often leads to accidents occurring by people scraping against the wall ties. This can cause considerable disruption in a building project.

A further problem with presently available wall ties is that the shape of the ends leads to mortar being pushed out of the way if it is inserted after laying of the upper block while the mortar is wet.

British Patent Specification No.s GB 2,073,279 A and GB 1,176,763 show wall ties which have circular apertures in the ends, into which mortar flows in use. It appears, however, that if the mortar is not completely fresh then it may not flow into the apertures to a sufficient extent.

Even if put in place immediately when the mortar is fresh, there is very little surface area of the tie engaging behind mortar. Accordingly, relatively little force is required to dislodge the wall tie.

The invention is directed towards providing a wall tie to overcome these problems.

According to the invention there is provided a wall tie having at least one end for engagement with mortar, wherein the mortar-engaging end comprises a strip of material having a formation protruding away from the plane of the strip.

Preferably, the formation is sloped sharply with respect to the plane in one longitudinal direction and is sloped more gradually in the other longitudinal direction.

In one embodiment the formation is formed from a partly cut-out portion of the strip.

Ideally, the partly cut-out portion is substantially circular in plan view.

In another embodiment the mortar-engaging end has at least two formations, two of the formations being sloped in mutually opposed directions.

In a further embodiment the outer extremity of the mortarengaging end has a relatively smooth edge.

In this embodiment the outer extremity is preferably of convex shape in plan view.

According to another aspect the invention provides a method of producing a wall tie comprising the steps of: feeding a pair of blank strips of material to a position close to each other in the longitudinXl direction; and simultaneously shearing the extremities of the ends to a smooth contour, and forming formations in the ends which protrude away from the plane of the strips.

Ideally, the formations are formed by a circular punch which has an inclined face.

According to a still further aspect, the invention provides a method of producing a wall tie comprising the steps of: feeding a pair of blank strips to a position close to each other in the longitudinal direction; and simultaneously forming formations in the two adjacent ends of the blanks.

The invention will be more clearly understood from the following description of some preferred embodiments thereof, given by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic perspective view showing a wall tie of the invention, in use; Fig. 2 is a side view of the wall tie; Figs. 3, 4 and 5 are plan views of different constructions of wall ties and anchors of the invention; and Fig. 6 is a diagrammatic side view showing a method of production of the wall tie of the invention.

Referring to the drawings there is shown a wall tie of the invention indicated generally by the reference numeral 1.

The wall tie 1 is shown being placed in position between a cavity wall having an inner leaf 2 and an outer leaf 3.

As shown more clearly in Fig. 2, the wall tie 1 has two mortar-engaging ends, namely, 5(a) and 5(b). The wall tie is formed from a strip of uniform stainless steel which is twisted between the ends at 6 for dripping of moisture, in use. The mortar-engaging ends 5(a) and 5(b) each have formations which protrude away from the plane of the stainless steel strip. These formations are formed from partly cut-out portions of the strip which are punched in such a manner that they are inclined gradually in one longitudinal direction of the wall tie, the end face of the cut-out portion forming a sharp inclination in the opposite longitudinal direction. In more detail, the ends 5(a) and 5(b) have a pair of formations 7(a) and 7(b) respectively which are inclined upwardly and inwardly towards the centre of the wall tie as viewed in Fig. 2.

Each mortar-engaging end 5(a) and 5(b) also has a single formation 8(a) and 8(b) respectively, each of which is inclined upwardly and outwardly from the centre of the wall tie. The formations 8(a) and 8(b) are located closest to the centre of the wall tie.

In use, the wall tie 1 is placed in position as shown in Fig. 1 and mortar is placed on top of it, followed by the upper bricks or blocks. The weight of the upper block causes the wall tie to sink into the lower layer of mortar so that the mortar engages in the apertures. At the same time, the upper layer of mortar sinks down around the formations 7 and 8, and in particular engages the side edges of the formations.

Because the wall tie engages the mortar in two different manners i.e. at the aperture and at the cut-out portion or formation, the wall tie is anchored very strongly within the mortar. It has been found that significantly more force is required to pull the wall tie from the mortar after it has set than has heretofore been the case.

It will also be appreciated that the wall tie of the invention is extremely safe to handle because there are no sharp edges. As shown in the drawings, the extremities of the mortar-engaging ends 5(a) and 5(b) are rounded. It is also worth noting that the formations 7 and 8 do not have sharp edges which are accessible. The only possible sharp edges are the lower edges of the formations, which are not readily accessible. This is a major improvement over the handling of wall ties having bifurcated ends whereby even handling a wall tie by taking it out of a box would often cut one's hand. Another advantage is that if it is necessary to insert the wall tie after the blocks have been laid and the mortar is still wet, the wall tie may be pushed into position with minimum dislodging of mortar and a good grip would be created, provided the mortar is wet enough. While this is not the correct way to put a wall tie in position, in practice it is what often happens.

The invention is not limited to the embodiments described above. For example, the invention applies equally to anchors such as those shown in Figs. 3, 4 and 5. In Fig.

3 there is shown an anchor 10 having a mortar-engaging end 11 with formations 12 protruding upwardly and inwardly and a single formation 13 which protrudes upwardly and outwardly. The anchor 10 is twisted at the inner extremity of the mortar-engaging end 11 and the opposite end has a dovetail 14 for engagement with the slot in a pre-cast wall.

The anchor 15 shown in Fig. 4 is similar to the anchor 10 except that it is not twisted between the dovetail and the mortar-engaging end. An anchor 20 is shown in Fig. 5 which has a bracket 21 for holding retaining bolts. The important point of the invention is that the anchor or wall tie has a mortar-engaging end with formations which protrude away from the plane of the strip of material.

Indeed it is not essential that there be formations in opposite directions on a mortar-engaging end as there may be only one formation or a plurality of formations, all facing in the same direction.

The method of production of the wall tie 1 is now described with reference to Fig. 6. In this embodiment, the strip of material comes from a coil of stainless steel or mild steel which is delivered through a straightening station. The steel is pulled from the coil by a mechanical feed unit which draws the steel strip through the straightening station. The stroke of the feed unit is set to the required length of the wall tie. The straightened steel strip is then fed through a power press by the feed unit. The power press is shown in Fig. 6. As shown the diagram, the power press has a tool comprising a base 30 having punch-receiving holes 31. As shown in the drawing, the feed unit has supplied a blank 28. The general direction of travel is indicated by the arrow A, however, the blank is of course stationary at the power press.The press 2 also includes two sets of three punches 32 and 33. The punches 32 and 33 are circular in cross-section, and the cutting faces are inclined so that the formations 7 and 8 are punched on impact with the blanks 28 and 29. The tool also includes a shearing tool 34 for cutting the blank and rounding the extremities of the adjacent ends of the ties made from the blank. Thus, all of the operations of forming the formations and of shearing the extremities of the wall ties are carried out in a single operation. Another very important aspect of the production method is that because adjacent ends of two wall ties are formed simultaneously, a relatively simple setting of the production machinery, namely, the feed unit is all that is required for production of wall ties of different lengths. In other words the length of the wall tie does not affect the power press machine shown in Fig.

6. This is extremely important to allow quick batch changes between different lengths of wall tie. Of course, where different gauge steel is being used it is only necessary to increase the pressure of the tools 33 and 34 to make the necessary formations and shearing operation.

The twisting operation at the centre of the tie is carried out after the power press.

The wall tie may include a significant marking to indicate the correct embedment depth in either the inner or outer leaves. This would significantly help to ensure correct use.

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

Claims (12)

1. A wall tie having at least one end for engagement with mortar, wherein the mortar-engaging end comprises a strip of material having a formation protruding away from the plane of the strip.

2. A wall tie as claimed in claim 1 wherein the formation is sloped sharply with respect to the plane in one longitudinal direction and is sloped more gradually in the other longitudinal direction.

3. A wall tie as claimed in claims 1 or 2, wherein the formation is formed from a partly cut-out portion of the strip.

4. A wall tie as claimed in claim 3 wherein the partly cut-out portion is substantially circular in plan view.

5. A wall tie as claimed in any of claims 2 to 4 wherein the mortar-engaging end has at least two formations, two of the formations being sloped in mutually opposed directions.

6. A wall tie as claimed in any preceding claim wherein the outer extremity of the mortar-engaging end has a relatively smooth edge.

7. A wall tie as claimed in claim 6 wherein the extremity is of convex shape in plan view.

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

9. A method of producing a wall tie comprising the steps of: feeding a pair of blank strips of material to a position close to each other in the longitudinal direction; and simultaneously shearing the extremities of the ends to a smooth contour, and forming formations in the ends which protrude away from the plane of the strips.

10. A method as claimed in claim 9 wherein the formations are formed by a circular punch which has an inclined face.

11. A method of producing a wall tie comprising the steps of: feeding a pair of blank strips to a position close to each other in the longitudinal direction; and simultaneously forming formations in the two adjacent ends of the blanks.

12. A method substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

12. A method substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Amendments to the claims have been filed as follows .10 9. A method of producing a wall tie comprising the steps of: feeding a blank strip of material to a press machine; and simultaneously shearing the blank to form the extremities of the ends of two wall ties, and forming formations in the ends which protrude away from the plane of the strip.

10. A method as claimed in claim 9 wherein the formations are formed by a circular punch which has an inclined face.

11. A method of producing a wall tie comprising the steps of: feeding a blank strip of material to a press machine; and simultaneously shearing the blank to form the extremities of the ends of two wall ties, and forming formations in the two adjacent ends.