GB2221271A

GB2221271A - Brick tie

Info

Publication number: GB2221271A
Application number: GB8917074A
Authority: GB
Inventors: Thomas Pearson
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-26
Filing date: 1989-07-26
Publication date: 1990-01-31
Also published as: GB8817802D0; GB8917074D0

Abstract

A brick tie comprises a rod 12 threaded at a distal end and carrying a nut 20 for engagement of a predrilled hole in an inner skin of a cavity wall, a pair of expandable sleeves 24, 26 separated by a tapered boss 28 and a fixed nut or stop 30. In use, the brick tie is inserted through a hole drilled in the external skin of a cavity wall and driven into the hole drilled in the inner skin when tags 22 hold the nut 20 against rotation. A tool applied to the thread at the proximal end turns the rod through the nut 20 to cause the fixed nut or stop 30 to move axially with the rod and expand the sleeves 24, 26. A nut 32 is then placed on the proximal end and used to expand a similar pair of sleeves at that end. The sleeve may be split stainless steel tubes or deformable plastics tubes (24a, Fig. 5-8). <IMAGE>

Description

BRICK TIE This invention relates to a brick tie and in particular relates to a replacement tie for use with cavity walls where the ties are no longer functioning.

In the construction of buildings it is common to use a cavity wall construction in which two parallel walls of bricks, blocks or the like are built leaving an air gap or cavity there between. To give the structure as as whole stability the two skins" of the cavity wall are joined together at intervals by means of metal ties fixed into the mortar courses of the adjacent "skins" during building.

Such brick ties can take a variety of forms but are commonly galvanised steel wire in the form of a "bow tie" shape.

Such ties can, over a period of time, corrode until the structural integrity of the wall no longer meets relevant standards, In order to overcome this defect without demolishing the building and starting again is being proposed to use replacement ties which are inserted externally of the wall after construction. One such form of tie comprises an elongated steel rod threaded at either end and carrying in an expandable boss portion intended to fit into a pre-drilled hole and, after fitting in place, by appropriate manipulation of the rod expand the boss and grip the hole. Such devices, although useful, have not always been totally satisfactory since it is often difficult to cause the distal boss to grip its respective hole in the inner skin sufficiently tightly.

The invention seeks to provide a brick tie improved in the above respect.

According to the present invention there is provided a brick tie which comprises an elongate rod threaded at at least distal end and carrying at at least distal end a nut for engaging a pre-drilled hole in the inner skin of a cavity wall, at least a pair of expandable sleeves separated by a tapered boss, and a fixed nut or stop.

The provision of two expandable sleeves separated by a tapered boss has been found to improve dramatically the gripping ability of the distal end of the tie of the invention The invention will be described further, by way of example, with reference to the accompanying drawings in which: Figure 1. is a general perspective view of a tie in accordance with the invention; Figure 2. is an enlarged view of the distal expandable boss mechanism in its relaxed figuration; Figures 3a, 3b & c are respective and elevational views of the parts a, b & c in Figure 2; Figure 4. is a view corresponding to Figure 2. with the boss in its expanded condition; Figure 5. is a similar view to Figure 2. of another embodiment of the invention; Figure 6. is a similar view to Figure 4. of the embodiement of Figure 5.; Figure 7. is a similar view to Figure 2. of a third embodiement of the invention;; Figure 8. is a similar view to Figure 4. of the embodiment of Figure 7.; Figure 9. is an end view corresponding to Figure 5.

Referring to the drawings, and in particular Figures 1-4, a brick tie (10) in accordance with the invention comprises an elongate rod (12) preferably of a metal such as stainless steel, being threaded at both ends thereof. The rod (12) carries an expandable boss mechanism (14) at its distal end and another such mechanism (16) at its proximal end. A rubber collar (18) is also provided to provide a dripping point for condensation which may form on the rod in use and prevent the water being retained which would accelerate corrosion of the rod.

The expansion mechanism (14) and (16) are essentially the same in operation, and the operation weill be described with reference to the mechanism (14) shown in Figures 2. 3 and 4.

The expansion mechanism comprises a nut (20) provided with tags, nail, pins or the like (22) to grip the interior of a pre-drilled hole in a cavity wall and hold the nut (20) agaisnt rotation. A pair of split metal, for example stainless steel, sleeves (24, 26) are provided having a tapered boss (28) there between. The sleeves may have a longitudinally split cylindrical configuration. The mechanism is completed by means of another nut or stop (30).

In use. a hole is drilled completely through the external "skin" of a cavity wall and at least partly into the internal "skin". A tie (10) is then inserted distal end first so that the mechanism (14) locates in the hole drilled in the internal "skin". The hole should be just large enough to accommodate the mechanism (14) in its relaxed state. Thus, the tie may neeXd to be driven into the hole so that the pins (22) grip and hold the nut (20) against rotation. A suitable tool is applied to the thread at the proximal end of the tie rod (12) and the latter is turned.Since the nut (20) is stationary with the respect to hold the wall and the nut (30) stationary with respect to the rod, the two are drawn together thereby forcing the sleeves (26) to open and be drawn up the tapered portions of both of the nuts (20, 30) and the tapered boss (28). In the fully expanded form the mechanism takes the appearance showing Figure 4. In this configuratin, the sleeves (24) tightly grip the interior of the pre-drilled hole thus firmly locking the distal end of the tie into the inner "skin" of the cavity wall. The tool is removed and a nut (32) placed on the proximal end of the rod (12).

Tightening of the nut (32) causes the same operation to occur with the proximal mechanism (16) thus locking the tie into the adjacent "skin" of the cavity wall. The tie is now firmly locked in both "skins" of the wall and all that remains to be done is the hole made good with mortar.

Figures 5 and 6 illustrate another embodiment. like numbers will be used for like parts. In this, the stainless steel split sleeves (24) are replaced by deformable plastics eg PVC cylinders or tubes (24a). No split is necessary since the natural resilience of the PVC allows the expansion shown in Figure 6. to be achieved. Figures 7 and 8 show a similar embodiment to that shown if Figures 5 and 6 in which the nuts (20) are of a different configuration.

The brick tie of the invention has been found to work extremely well in practice and to produce a very strong grip even at the distal end where difficulty had hitherto been experienced. It is believed that the use of a pair of expanding members instead of the single one employed hitherto significantly contributes to this unexpectedly good performance.

Alternative embodiments of this invention may incorporate an extension rod provided with a threaded collar or other means facilitating extension of the rod to allow use with thicker walls or with walls having wider cavities.

Claims

1. A brick tie comprising an elongate rod having a distal end and a proximal end and being threaded at at least the distal end and carrying at at least the distal end a nut for engagement of a pre-drilled hole in the inner skin of a cavity wall, a pair of expandable sleeves separated by a tapered boss, and a fixed nut or stop.

2. A brick tie as claimed in Claim 1, wherein each sleeve comprises a longitudinally split cylindrical metal sleeve.

3. A brick tie as claimed in Claim 1, wherein each sleeve comprises a deformable plastics cylinder.

4. A brick tie as claimed in any preceeding claim wherein the boss comprises a tubular member with tapering surfaces at each end.

5. A brick tie substantially as hereinbefore descirbed with reference to the accompanying drawings.