GB2332696A - Remedial wall tie - Google Patents

Abstract

A wall tie comprises a tie rod 10 having at its distal end a nut 20 which acts as a stop for a distal expansible portion 14 and a second expansible portion 16 at its proximal end wherein the tie rod 12 is surrounded by a sleeve 24 between the distal and proximal expansible portions. The sleeve 24 is a rigid tube manufactured from a metal such as stainless steel or a plastics material such as rigid PVC. The distal nut 20 locks in the brickwork of the inner leaf of a wall and rotation of the proximal nut 22 causes the whole unit to be compressed axially and since the tube is rigid both the distal and proximal neoprene portions expand radially locking the tie to the inner and outer leaves of the wall simultaneously.

Description

WALL TIE This invention relates to wall ties for tying together the inner and outer leaves of cavity walls.

In the cavity wall construction commonly used for many buildings, the inner and outer leaves of cavity walls are tied together using metal wall ties during building. In certain circumstances the ties can corrode and the fixing between the inner and outer leaves become destroyed allowing walls to bow or otherwise move.

There have been proposed, therefore, a number of wall ties designed to be fitted to an existing building usually from the outside thereof, which comprise a tie body with expandable elements at each end so designed that both the remote and proximal expandible elements can be expanded by a tool applied externally of the outer leaf. Such wall ties are in common use for remedial work and are very efficient.

However, they require a special tool in order to be fixed and it is usually a two step process whereby the tool is used to expand the remote expansible portion fixing the tie in the inner leaf, and then a separate tool, or a different part of the same tool, is employed to expand the proximal expansible portion thus fixing the tie and the outer leaf and completing the process.

The invention seeks to provide a wall tie which can be expanded in both proximal and distal expansible portions in a single operation.

According to the present invention there is provided a wall tie which comprises a tie rod having, at its distal end, a nut which acts as a stop for a distal expansible portion, and a second expansible portion at its proximal end, characterised in that the tie rod is surrounded by a sleeve or tube between the distal and proximal expansible portions.

In a common form of available wall tie, the tie rod, being a threaded rod, carries a nut at its distal end, a length of neoprene sleeve adjacent the nut, and a second nut, together defining the distal expansible portion. A similar arrangement is carried at the proximal end. The distal end is expanded by using a tool which grips the threaded portion and turns it relative to the distal nut which is crimped or otherwise distorted so as to lock into the brickwork of the inner leaf of the wall. Turning the rod causes relative movement between the nut and the rod thereby axially compressing the neoprene and causing it to expand radially and lock in the drilled hole. Once the distal end has been locked into the inner leaf, the tool is removed from the thread and applied to the proximal nut when further rotation will cause the proximal expansible portion to lock in the outer leaf in a similar manner.

By contrast, in accordance with the invention, only a distal and proximal nut are provided and between the expansible portions is a rigid tube manufactured from a metal, such as stainless steel, or plastics material, such as rigid PVC.

The distal nut locates in the brickwork of the inner leaf as before and rotation of the proximal nut causes the whole unit to be compressed axially and since the tube is rigid both the distal and proximal neoprene portions expand radially, locking the tie to the inner and outer leaves of the wall simultaneously.

Instead of a neoprene expandible sleeve, the commonly known cone and split steel expanders may be used and the result is the same.

A particular advantage of the tie of the present invention is that it can still be employed in the same manner as conventional wall ties, i.e. with the distal expansible portion being locked first using a tool on the thread rather than on the proximal nut. This may be necessary when it is required to check that the inner leaf end is properly locked in place.

However, with the tie of the invention it is unnecessary to carry out the above "pull-out" checks for the following reason. If the distal neoprene sleeves are expanded by rotation of the proximal nut. If the nature of the hole in the inner leaf is such that it is incapable of sustaining a mechanical fix, the distal neoprene sleeve continues to expand resulting in the tie rod continuing to be drawn back through the proximal nut. Further more, if a torque control power screwdriver is employed, this will continue to rotate as the required torque will not be reached. Both of these indications are apparent to the operative who can then remove and refix the tie rod in a suitable location. If, on the other hand, the clutch on the torque control power screwdriver slips at its preset value, then both sleeves will have achieved mechanical fix - including the sleeve in the inner leaf. Thus, no independent check of inner leaf fixing is necessary with the tie rod of the invention. Moreover, if a second, independent check is specified this can be carried out afterwards with another torque control device where, once again, if the device reaches the preset torque and then slips this is sufficient indication that both the outer and inner sleeves are fixed in the respective leaves.

In another embodiment of the invention the distal nut is replaced by an integrally formed head of an irregular shape capable of gripping the brickwork of the inner leaf. This form of the invention is cheaper to manufacture but its expansible portions can only be expanded simultaneously.

The invention will be described further, by way of example, with reference to the accompanying drawing in which: Figure 1 is a diagrammatic perspective view of a wall tie in accordance with the invention; Figure 2 is a similar view to figure 1 with the expansible portions expanded; Figure 3 is a similar view to figure 1 employing a stainless steel expander; and Figure 4 illustrates the tie of figure 1 being operated in a conventional manner.

Referring to the drawings, and in particular figures 1 and 2, it will be seen that a wall tie generally designated 10 comprises a threaded rod 12 having a distal 14 and proximal 16 expansible portion. Each expandible portion 14,16 comprises a neoprene sleeve which, when compressed axially, expands radially as is known in the art.

The rod 12 carries a distal nut 18 which maybe crimped or otherwise deformed at 20 so as to engage the brickwork of an inner leaf of a wall (not shown) although it has been found that a conventional nut may be employed in almost all occasions as the grip is usually sufficient. A proximal nut 22 is also provided. In accordance with the invention there is provided a sleeve or tube 24 between the distal 14 and proximal 16 expansible portions. The tube 24 is sufficiently rigid to resist axial pressure.

In use, a hole is drilled from the outside of the building through the outer leaf and into the inner leaf as is known in the art. The wall tie 10 of the invention is inserted from the outside so that the distal end locates in the hole in the inner leaf where the nut 18 locks against rotation. Turning the nut 22 axially compresses the expansible portions 14,16 (the tube 24 being rigid) and both therefore expand radially and lock within the drilled holes in the inner and outer leaves of the wall respectively. Thus a single process locks the tie in place rather than the two stage process previously required. The labour therefore needed is reduced considerable lowering the cost of remedial tie work. If a torque controlled power screwdriver 26 is employed the fitting of each tie can be done in seconds once the holes have been drilled.

Figure 3 is a similar view to figure 1 in which the neoprene expansible sections 14,16 have been replaced by standard stainless steel tapered cone expansible portions 14,16.

Turning now to figure 4, if it is desired to operate the tie of the invention in the conventional manner, i.e. by expanding the distal expansible portion 14 first, this can be achieved by the tie of the invention. The hole is drilled and the tie put in place as before but firstly a tool is engaged with the threaded rod 12 which rotates the rod. The nut 18, being held in the brickwork of the inner leaf, cannot rotate, and the distal portion 14 is thereby expanded.

Removing the tool and tightening the nut 22 as before completes the expansion of the proximal portion 16 locking the tie in the outer leaf also.

It will appreciated that while the above has been described with reference to fitting a tie from the outside it can also be fitted from the inside in which case "outer" and "inner" are reversed.

The wall tie of the invention is cheap and easy to assemble, it is also very easy to use and reduces labour costs in remedial wall tie work.

Claims (7)

1. CLAIMS 1. A wall tie which comprises a tie rod having, at its distal end, a nut which acts as a stop for a distal expansible portion, and the second expansible portion at its proximal end, characterised in that the tie rod is surrounded by a sleeve or tube between the distal and proximal expansible portions.
2. 2. A tie rod as claimed in claim 1 in which the sleeve comprises a rigid tube.
3. 3. A tie rod as claimed in claim 2 in which the tube is manufactured from a metal or a plastics material.
4. 4. A tie rod as claimed in any of claims 1-3 in which the expansible portions comprise neoprene expandible sleeves.
5. 5. A tie rod as claimed in any of claims 1-3 in which expandible portions comprise cone and split steel expanders.
6. 6. A tie rod as claimed in any of claims 1-5 in which the distal nut is replaced by an integrally formed head of a regular shape capable of gripping the brickwork of the inner leaf.
7. 7. A tie rod substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.