GB2443476A

GB2443476A - Sliding wall tie and sleeve

Info

Publication number: GB2443476A
Application number: GB0621631A
Authority: GB
Inventors: Paul Butler
Original assignee: Wincro Metal Industries Ltd
Current assignee: Wincro Metal Industries Ltd
Priority date: 2006-10-31
Filing date: 2006-10-31
Publication date: 2008-05-07
Also published as: GB0621631D0

Abstract

The invention relates to a movement restraint e.g. a debonding sleeve for use between two wall sections. The restraint allows the wall sections to move a limited distance, such as a result of wind pressure acting on the wall. The movement restraint comprises an elongate plastics sleeve 10 with a flat bottomed cavity 16 and a metal tie part 12. The sleeve has a projection 18 upstanding from the cavity wall that acts as an initial stop when the metal tie is inserted during installation. The projection prevents the tie from being set too deep within the sleeve resulting in the restraint becoming ineffective. Once the tie has been set against the projection and the restraint installed in a joint between two walls, the tie is able slide relative to the sleeve. When the tie moves into the sleeve against the projection, the metal tie will cut the projection as it slides further into the sleeve past the projection.

Description

Movement restraint.

The invention relates to a movement restraint for use in the building industiy.

All masonry structures are subject to some movement after construction, such movements being due to various influences such as ground movements and changes of temperature. Provision for such movements must be made when buildings are being designed and one of several commonly employed movement restraints which are available for such use is a so-called de-bonding sleeve by means of which masonry is allowed to expand or contract in one direction whilst at the same time being restrained against lateral movements in another.

A de-bonding sleeve comprises an elongate sleeve element within which a metal tie is slidably located to extend some distance beyond an outer end of said sleeve. In use of the device the sleeve is fixedly located in one element of a masonry joint and the projecting end of the metal tie is fixedly located in the other element of the joint, with some empty space remaining at the inner end of the sleeve element to permit some free longitudinal movement of the tie. In this way the two elements of the masonry joint are connected together for mutual support in one direction whilst being able to move freely, to some relatively small extent, in the other.

It is usual for building workers to be instructed to install such devices with a certain amount of free movement within them, that is to say with that certain amount of open space remaining at the inner end of the sleeve element, the length of this space being considered to be, for example, the maximum amount of wind deflection which need be catered for; and it has previously been proposed to provide a sight hole in the wall of the sleeve element, spaced from its inner end, so that, on installation, the inner end of the metal tie can very easily be located at the recommended location within said sleeve element.

However, there is one particular drawback in the use of such movement restraints, this being that, in their haste to lay the most bricks in the minimum of time, some workmen may forget the instruction to install the ties with a certain amount of free movement still possible; consequently, in this case, they install at least some of the restraints with the metal ties filly inserted in their sleeves with the result that those particular ties are unable to slide freely to absorb wind loads, for example, or indeed movements produced in any other way.

According to the invention, there is provided a movement restraint including an elongate plastics sleeve element and a metal tie element slidably located in said sleeve element, the sleeve element being provided near its inner end with a projection upstanding from one side wall so that the effective width of the cavity in that region is less than the thickness of the steel tie, thus producing an initial stop point for said tie as it slides into the sleeve, the arrangement being such that, in use, the restraint can be installed within a masonry joint with the tie positioned within the sleeve at the initial stop point, any subsequent movement of the joint tending to reduce the overall length of the restraint causing the inner end of the metal tie to slice off an end portion of the * -3-projection and being able to move freely as intended to allow the fill range of movement for which the restraint has been provided.

In order that the invention may be flilly understood and readily carried into effect, a preferred embodiment will now be described, by way of example only, with reference to the accompanying drawings, of which:-Figure 1 is a side view of a movement restraint embodying the invention, Figure 2 is a plan view, and Figure 3 is a sectional view on the line 3 -3 in Figure 2, this being drawn at a somewhat larger scale than Figures 1 and 2.

Referring now to the drawngs, the movement restraint there illustrated is comprised of two parts, an elongate plastics sleeve element 10 and a metal tie 12 slidably located in said sleeve element (the tie having been formed from a length of steel strip and, in the case of the illustrated example, one end portion having been provided with a series of holes 14 so that, in use, when embedded in mortar, the latter can flow freely through said holes, the end of the tie thus becoming effectively anchored).

The sleeve element 10 is provided with a flat bottomed cavity 16 of a cross section very slightly larger than that of the steel strip so that the latter can slide freely into it. However, near the bottom of the cavity, there is provided a projection 18 on one side wall, this reducing the effective width of the cavity at that point to slightly less than the thickness of the steel tie.

In Figures 2 and 3 the inner end of the tie is shown to be abutting against one side of the projection. In this position, the tie is positioned within the sleeve at -.4-what can be termed an initial stop point, that is to say at a location in which the length of space remaining at the inner end of the sleeve element is considered to be, for example, equal to the maximum amount of wind deflection which need be catered for. The arrangement is such that, when installed in a masonry joint, with the tie element positioned at the initial stop point, any movement of the joint tending to reduce the overall length of the restraint will cause the inner end of the metal tie to slice off an end portion of the projection IS; the restraint will then perform, in exactly the same way as a conventional masonry restraint, in allowing the masonry to expand or contract in one direction whilst at the same time restraining it against movement in another. It will be understood that, since it will not be possible for a workman to slice off the projection by applying only manual effort to the tie before he has installed the restraint, there is no chance of the restraint being wrongly installed in the manner previously described.

Various modifications may be made. For example, the sleeve elements could be moulded with an indication of how much free movement of a joint they are designed to allow. Indeed it would be possible to produce a restraint embodying the invention and having a variable amount of free movement after the initial cutting of the projection as the initial stop point is passed. It will be understood that the outer end portion of the metal tie element may be differently formed; it need not be adapted to be secured in position by mortar and could be adapted to be secured in position by a bolted connection for

example.

Claims

Claims I. A movement restraint including an elongate plastics sleeve

element and a metal tie element slidably located in said sleeve element, the sleeve element being provided near its inner end with a projection upstanding from one side wall so that the effective width of the cavity in that region is less than the thickness of the steel tie, thus producing an initial stop point for said tie as it slides into the sleeve, the arrangement being such that, in use, the restraint can be installed within a masonry joint with the tie positioned within the sleeve at *S the initial stop point, any subsequent movement of the joint tending to reduce the overall length of the restraint causing the inner end of the metal tie to slice off an end portion of the projection and being able to move freely as intended to allow the full range of movement for which the restraint has been provided. * *
2. A movement restraint according to claim 1, in which the sleeve element has been moulded with an indication of how much free movement it has been designed to allow.
3. A movement restraint according to either one of the preceding claims, in which one end portion of the metal tie has been provided with at least one hole so that, in use, when being embedded in mortar, the latter can flow freely through said at least one hole, the end of the tie thus becomming effectively anchored therein as the mortar sets.
4. A movement restraint constructed, arranged and adapted to be used substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings. S. * . * ..* *.** * S * S * S. S *. * S S...

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