GB2260348A

GB2260348A - Wall tie

Info

Publication number: GB2260348A
Application number: GB9221772A
Authority: GB
Inventors: Graham Law; Zdzislaw Jozef Szewczyk
Original assignee: ANCON STAINLESS STEEL FIXINGS
Current assignee: ANCON STAINLESS STEEL FIXINGS
Priority date: 1991-05-01
Filing date: 1992-04-27
Publication date: 1993-04-14
Anticipated expiration: 2012-04-27
Also published as: GB2260348B; GB9209071D0; GB2260349A; GB2255358A; GB9221773D0; GB2260349B; GB9221772D0; GB2255358B

Abstract

A wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction and a central drip-forming region having longitudinal sides provided with notches 38 and/or projections 40 on the upper and lower edges such that drip formation is encouraged whichever way up the tie is installed. <IMAGE>

Description

WALL TIES This invention relates to wall ties, more particularly to a wall tie having improved rigidity and strength, and which in preferred embodiments can be anchored in mortar with improved pull-out performance.

Wall ties are used in the construction of walls made of brick, stone, masonry and other forms of cladding and construction materials. One common form of wall construction, used in the building of domestic houses and flats, and in municipal buildings, is the cavity wall, in which an outer and an inner wall are separated by a gap of usually from 5 to 15 cms. The outer wall, which is exposed to the elements, is normally made from an environmentally resistant material such as brick or stone. The inner wall may be made of the same materials, but quite commonly can be made of less durable materials such as breeze block, plasterboard, and composite constructions.

The cavity wall is strengthened by the provision of metal ties which extend between the walls at intervals and have their ends anchored to the walls. Where both walls are of brick, stone, or other block construction, the wall ties are anchored at their ends in the layer of mortar used to bind the brick, stone, or blocks together.

A very large variety of wall ties have been proposed in the prior art. Many such ties comprise heavy gauge metal wire bent into a butterfly-type shape, for example, as described in UK patent No 2062719. In general, such ties lack the necessary rigidity for many building applications and specifications.

Other ties have been proposed which are made from metal strip which is stamped or bent into various configurations. A typical example is shown in UK patent application No 2052601 in which the two ends of the tie, which are anchored to the sides of the cavity wall, are joined by a section in the form of an inverted V. This, as with many similar constructions, is intended to prevent the wall tie acting as a bridge for water passing across from the outer to the inner wall. Other means for preventing water travelling along the tie comprise small Ushaped or cranked lengths of the central section of the tie which provide a region for water to collect and drip off, for example as disclosed in UK patent No 2095305. Such a means is known as a "drip". All these "drip" means introduce a point of weakness into the tie.

In yet another known construction, as shown in UK patent application No 2230544, the central section of the tie is inclined downwardly towards the outer wall, again in an attempt to prevent water travelling along the tie.

The disclosures of all these prior patents are incorporated herein by reference.

The proposals of the prior art have many disadvantages.

Many are not strong enough for current or proposed building regulations, and others are complicated to manufacture resulting in increased costs. Many of the prior art proposals are not easy to install on site and are not symmetrical, so that they must be installed the correct way up to function properly. Others have inadequate pull-out strength when anchored in the mortar of a wall.

A general problem with wall ties which further complicates the situation, is that they should not allow wet mortar dropped during the construction of the wall to catch on the central section, thereby bridging the cavity and providing a pathway for moisture transfer.

It has been proposed, for example as shown in UK patent applications Nos. 2052601 and 2230544 to twist the central section of the tie so that it lies in a vertical plane, edge-on to any falling mortar, in order that mortar is not so easily trapped thereby. However, these constructions have other disadvantages as mentioned above.

We have now discovered an improved wall tie which in one aspect has a central region formed into a profile having improved rigidity in comparison with a flat sheet of metal of equal size and thickness, whilst still presenting a narrow cross-section to falling mortar, so that the risk of the latter being caught by the tie is substantially reduced. In another aspect the improved wall tie has increased pull-out strength, is easy to manufacture, and is easy to install safely. In preferred embodiments the improved wall tie can be made symmetrical in construction.

The present invention provides a wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction and a central profiled region, at least one end region and/or the central profiled region having longitudinal sides inclined transversely to the plane of the strip.

Preferably the wall tie has at least one longitudinally slotted section, the longitudinal sides of the slotted section being inclined transversely to the plane of the strip.

The wall tie of the present invention is preferably made in one piece from a suitable metal strip such as for example stainless steel, or some other environmentally resistant metal.

At least one end region of the tie will normally be adapted to be embedded in the layer of mortar used to bind the brick, stone, or blocks of the wall together. Where two brick, stone, or block walls are used to construct a cavity wall, the wall tie will usually have both end regions similarly adapted.

However the invention-also includes a wall tie in which one or both end regions are adapted to be secured, for example by the provision of screw or nail-holes, to a wooden structure, or to a plasterboard or composite board surface. The invention also includes a wall-tie in which one end region is adapted to fit into, and be secured to, a channel cast into a concrete wall or column, for example, as described in UK Patent Application No. 9023695. Preferably the or each end region of the tie which is adapted to be received in the layer of mortar is slotted, in order to provide a key for the mortar of the brick, stone, or block work.The slot is preferably expanded to a diamond configuration to improve the anchorage, and, in accordance with the invention, the sides of the slots can be inclined transversely to the plane of the metal strip which also helps keying of the mortar. The length and width of the slots can be varied to suit the application.

The slotted end regions are particularly preferred, and have a particular advantage over the commonly used fish-tail end regions, for example as shown in UK patent application No 2111095, in that they can be made without sharp ends, that is to say, without sharp edges or corners which can cause accidents on site. This is because the wall ties are often inserted in one of the cavity walls as it is being constructed, and protrude out from the wall. The second wall may not be built until some time later and these protruding wall ties with sharp ends can therefore represent a hazard to workers on the site. In UK patent No 2095305, there is disclosed a wall tie which has been slit and expanded to provide two pairs of strands each connected to a central portion. This construction however is still shown having sharp points at its ends which could constitute a hazard in the above described situation.

The central region of the wall tie according to the invention is preferably formed from a flat sheet bent into a profile such that the strength and rigidity of the central region against compression, tensile stress, twisting and bending forces is improved. Such an improvement can be obtained, for example, by bending the longitudinal sides downwards to form a profile of U-shaped cross section, or more complex shapes such as M- or H-shaped cross section profiles can be formed. Alternatively the longitudinal sides can be bent to form a profile of dumb-bell shaped cross section. For ease of manufacture, combined with excellent mechanical strength an M-shaped cross section profile is preferred.

Preferably the thickness of the metal strip is from 1.0 mm to 1.5 mm. The width of the profile is preferably from 15.0 to 30.0 mms, most preferably from 19.0 to 26.0 mms such as, for example, 20 or 25 mms, and the height of the transversely inclined longitudinal sides is preferably from 5.0 to 6.0 mms.

The central region of the wall tie is preferably also provided with a "drip" to encourage droplets of water, which may have soaked through the outer wall, to drip from the central region without traversing the tie to the inner wall.

The drip may be provided by giving the central region of the wall tie a vertical twist, or by providing a horizontal channel in the central region directed transversely to the axis of the wall tie.

However, in a preferred aspect of the invention, there is provided a wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction, and a central region which comprises a longitudinally slotted section, the longitudinal sides of the slotted section being inclined transversely to the plane of the strip.

The central region of the wall tie, according to this aspect of the invention is provided with a longitudinally directed slot which is preferably of a width sufficient to allow lumps of mortar to pass through it without becoming caught. Preferably the width of the slot is from 1 to 1.5 cms.

The sides of the slot are inclined transversely to the plane of the strip thereby presenting a narrower aspect and constituting a smaller obstruction to falling mortar. In addition, by inclining the sides of the slot a "drip" is formed in the central region of the wall tie.

In this embodiment, one or both of the end regions of the wall tie may also be slotted, and the wall tie may be formed symmetrically by punching three slots along the length of a metal strip and bending the walls of the slots so that they are inclined transversely to the plane of the strip. It can be seen that for each slot the machining operation can be the same. In the final stage of manufacture the slots at the two end regions are expanded to a diamond configuration. The manufacturing operation is thus both simple and inexpensive.

In another preferred aspect of the invention, the drip can be formed by perforations drilled or stamped out of the central region. Such a "drip" formed by a perforated central region is a separate and distinct aspect of the present invention. Notches and projections on the upper and lower edges of the longitudinal sides are preferably provided such that drip formation is encouraged which ever way up the wall tie is installed. Such notches and projections in combination also form a separate and distinct aspect of the present invention.

The length and width of the longitudinally directed slot, or the diameter and number of the holes forming the perforations, should not be such as to weaken substantially the mechanical strength of the central region.

Various embodiments of the invention will now be described with reference to and as illustrated in the accompanying Drawings in which: Figure 1 shows a plan view of a first wall tie according to the invention; Figure 2 shows the same wall tie in side elevation; Figure 3 shows a perspective view of a the wall tie of Figures 1 and 2 with drip-forming notches; Figure 4 shows a perspective view of a second wall tie according to the invention; Figure 5 shows a perspective view of a third wall tie according to the invention; and Figure 6 shows cross-sections through the central regions of various alternative constructions of wall tie according to the invention.

Figures 7 to 9 show in perspective view various wall ties adapted to be secured to a wall by a variety of fixing methods.

Referring to Figures 1 to 3, the wall tie, generally illustrated at 1, comprises a central section 2, and end sections 3 and 4. The central section is provided with a longitudinal slot 5, having transversely inclined sides 6 and 7. The central section 2 is joined to the end sections by webs 8 and 9. The end sections 3 and 4 are provided with diamond shaped openings 10 and 11 having transversely inclined sides 13 and 14. Each end section is provided with rounded corners 15, 16, 17 and 18 so as not to leave any sharp edges to constitute a hazard. Drip-forming notches 19 are provided on the lower edges of sides 6 and 7 in Figure 3.

In use the end sections 3 and 4 and the webs 8 and 9 are embedded in the mortar of the cavity walls, and the central slotted section 2 extends therebetween. The sides 6 and 7 are edge-on to any falling mortar thus reducing the risk that the mortar will be caught on the tie. In addition, the lower edges of the sides 6 and 7 encourage drip formation thus reducing the likelihood that water will travel across the tie from the outer to the inner wall.

It has been found that this combination of the dual-sided central section and the keying strength provided by the diamond shaped end regions results in a wall tie having greatly improved rigidity and pull-out strength values. The symmetry of the design avoids the risk, common in many prior art designs, that the wall tie can be installed in an inverted manner.

Referring to figure 4, the wall tie generally illustrated at 21, comprises a central region 22, and end regions 23 and 24. The central region is of M-shaped cross section, having transversely inclined sides 25 and 26. The end regions 23 and 24 are provided with diamond-shaped openings 27 and 28 having transversely inclined sides 29, 30, 31 and 32. Each end region is provided with rounded corners 33, 34, 35 and 36 so as not to leave any sharp edges to constitute a hazard. The "drip" is formed by perforations 37 and by notches 38 in the sides 25 and 26. Both the perforations and the notches assist in drip formation, so that the wall tie can be installed as shown, or in an inverted manner, and the drip will continue to function.

Referring to Figure 5, an alternative form of drip is shown which comprises a centrally disposed slot 39. The slot has upstanding projections 40 in its side walls which assist in drip formation if the wall tie is installed in an inverted manner. Notches 38 are again formed in side walls 25 and 26 to perform a similar function when the wall tie is installed as shown.

Referring to Figure 6, a variety of cross sections of suitable profiles for the central region are shown. From left to right these are an Shaped cross section, a flattened inverted U-shaped cross section, an inverted U-shaped cross section, an H-shaped cross section, and a dumb-bell-shaped cross section.

In use the end regions 23 and 24 are embedded in the mortar of the cavity walls, and the central profiled region 22, extends therebetween. The wall tie central region is of relatively narrow width and thus reduces the risk that any falling mortar will be caught on the tie. In addition, perforations 37, the slot 39, projections 40 and notches 38 encourage drip formation thus reducing the likelihood that water will travel across the tie from the outer to the inner wall.

Again the combination of the profiled central region and the keying strength provided by the diamond shaped end regions results in a wall tie having outstanding mechanical strength and pull-out values. By using water drips on both upper and lower surfaces of the central region of the tie, the risk, that the wall tie can be installed in an inverted fashion, such that the drip does not function correctly, is avoided.

Referring to Figure 7, there are shown various wall ties adapted to fit into channels 50 and 51, which in use would be set into a concrete wall or pillar, or fastened thereto. The ties, 52, 53, 54, and 55, are provided with T-shaped ends 56, 57, 58 and 59 which can be received in and secured to the channels 50 and 51. Wall ties 53 and 55 also have transverse V-shaped channels 60, 61 which act as water drips for the central region.

Figure 8 shows two similar wall ties 70, 71, having upstanding projections, 72, 73 with screw holes for connecting the wall tie to a vertical surface.

Figure 9 shows a wall tie 80 according to the invention, having a plastic debonding sleeve 81. The ends 82, 83 of the wall tie are embedded in the mortar of adjacent sides of a cavity wall, and the presence of the plastic debonding sleeve 81 allows a certain amount of horizontal movement of the two leaves of the cavity wall with respect to one another.

The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

Claims

1 A wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction and a central drip forming region, the central drip forming region having longitudinal sides provided with notches and/or projections on the upper and lower edges thereof such that drip formation is encouraged whichever way up the wall tie is installed.

2 A wall tie according to claim 1, in which the central drip forming region is profiled and has longitudinal sides inclined transversely to the plane of the strip.

3 A wall tie according to claim 1 or 2, which has at least one longitudinally slotted section, the longitudinal sides of the slotted section being inclined transversely to the plane of the strip.

4 A wall tie according to any of the preceding claims, which is made in one piece from a strip of an environmentally resistant metal.

5 A wall tie according to any of the preceding claims, in which the metal is stainless steel.

6 A wall tie according to any of the preceding claims, having at least one end region adapted to be embedded in a layer of mortar.

7 A wall tie according to claim 6, in which the end region is slotted to provide a key for the mortar.

8 A wall tie according to claim 7, in which the sides of the slot in the end region are inclined transversely to the plane of the metal strip.

9 A wall tie according to any of the preceding claims, that is made without sharp ends.

10 A wall tie according to claim 2, in which the longitudinal sides are bent downwards to form a profile of U-shaped, Mshaped, H-shaped or dumb-bell shaped cross-section.

11 A wall tie according to claim 10, in which the height of the transversely inclined longitudinal sides is from 5.0 to 6.0 mm.

12 A wall tie according to any of the preceding claims, in which the central drip forming region comprises a longitudinally slotted section, the longitudinal sides of the slotted section being inclined transversely to the plane of the strip.

13 A wall tie according to claim 12, in which the width of the slot is from 1 to 1.5 cms.

14 A wall tie according to any of the preceding claims, which is formed symmetrically by punching three slots along the length of the metal strip and bending the walls of the slots so that they are inclined transversely to the plane of the strip.

15 A wall tie according to claim 14, in which the slots at the two end regions are expanded to a diamond configuration.

16 A wall tie according to any of the preceding claims substantially as described with reference to and as illustrated in Figures 1, 2 and 3 of the Drawings.

17 A wall tie according to any of the preceding claims, comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction, and a central region formed into a profile having improved rigidity in comparison with a flat sheet of metal of equal size and thickness.

18 A wall tie substantially as hereinbefore described.

19 A wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction and a central profiled region, at least one end region and/or the central profiled region having longitudinal sides inclined transversely to the plane of the strip.

20 A wall tie according to claim 19, which has at least one longitudinally slotted section, the longitudinal sides of the slotted section being inclined transversely to the plane of the strip.

21 A wall tie according to claim 19 or 20, which is made in one piece from a strip of an environmentally resistant metal.

22 A wall tie according to any of claims 19 to 21, in which the metal is stainless steel.

23 A wall tie according to any of claims 19 to 22, having at least one end region adapted to be embedded in a layer of mortar.

24 A wall tie according to claim 23, in which the end region is slotted to provide a key for the mortar.

25 A wall tie according to claim 24, in which the sides of the slot in the end region are inclined transversely to the plane of the metal strip.

26 A wall tie according to any of claims 19 to 25, that is made without sharp ends.

27 A wall tie according to any of claims 19 to 26, in which the longitudinal sides of the central region of the wall tie are bent so that they are inclined transversely to the plane of the metal strip.

28 A wall tie according to claim 27, in which the longitudinal sides are bent downwards to form a profile of Ushaped, M-shaped, H-shaped or dumb-bell shaped cross-section.

29 A wall tie according to claim 27 or 28, in which the height of the transversely inclined longitudinal sides is from 5.0 to 6.0 mm.

30 A wall tie according to any of claims 19 to 29, in which the central region is provided with a "drip" such that, in use, droplets of water, which may have soaked through the outer wall, drip from the central region without traversing the tie to the inner wall.

31 A wall tie comprising a strip of metal have end regions adapted to be anchored to respective sides of a cavity wall construction, and a central drip forming region which comprises a longitudinally slotted section, the longitudinal sides of the slotted section being inclined transversely to the plane of the strip.

32 A wall tie according to claim 31, in which the width of the slot is from 1 to 1.5 cms.

33 A wall tie according to any of claims 19 to 32, which is formed symmetrically by punching three slots along the length of the metal strip and bending the walls of the slots so that they are inclined transversely to the plane of the strip.

34 A wall tie according to claim 33, in which the slots at the two end regions are expanded to a diamond configuration.

35 A wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction and a central region having a "drip" formed by perforations drilled or stamped out of the central region.

36 A wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction and a central drip forming region, the central drip forming region having longitudinal sides provided with notches and/or projections on the upper and lower edges thereof such that drip formation is encouraged which ever way up the wall tie is installed.

37 A wall tie according to any of claims 19 to 34 having perforations, notches, or projections according to claim 35 or 36.

38 A wall tie according to any of claims 19 to 37 substantially as described with reference to and as illustrated in Figures 1 and 2 of the Drawings.

39 A wall tie according to any of claims 19 to 37 substantially as described and as illustrated in Figures 4 to 6 of the Drawings.

40 A wall tie according to any of claims 19 to 37 substantially as described and as illustrated in Figures 3, 7, 8 and 9 of the Drawings.

41 A wall tie comprising a strip of metal having end regions adapted to be anchored to respective sides of a cavity wall construction, and a central region formed into a profile having improved rigidity in comparison with a flat sheet of metal of equal size and thickness.

42 A wall tie substantially as hereinbefore described.