GB2144169A - Ties for existing cavity walls - Google Patents

Abstract

The tie has wall-grippers 10, 12 spaced on elongate member 30. Both grippers are operated from one end of the member, that furthest, 12, by rotation of member 30 and that nearest, 10, by rotation of a part 32 on member 30. The gripper may comprise expansion-sleeves 14,16 spread by conical member 18,20. Member 20 may be a nut mounted on screw-threaded end 34 of member 30, whereas member 18 may be clear of screw-threaded end 32, being driven by nut 36. Abutments 22,24 on member 30 prevent sleeves 14,16 shifting with members 18,20. <IMAGE>

Description

SPECIFICATION Cavity wall tying This invention relates to cavity wall ties.

There are many buildings of cavity wall construction where it is inevitable that the effectiveness of ties installed at building, and often being no more than bent wire, has, with the passage of time, deteriorated through corrosion and/or failure of anchoring mortar between courses of bricks or blocks to the point where they are not doing or not capable of doing the job required of them. The result, eventually, is a wall that is particularly vulnerable to collapse and thus likely to require expensive rebuilding.

We believe that there is a need for a cavity wall tie that can be neatly and readily installed in existing cavity walls as a preventive measure against possible consequences of known or suspected deterioration of original ties. It is an object of this invention to satisfy such need.

According to one aspect of this invention, there is provided a cavity wall tie device comprising an elongate member carrying spaced wall grippers both operable from one end of said member, that furthest therefrom by rotation of said member and that closest thereto by rotation of a part on said member near that one end.

According to another aspect of this invention, there is provided a method of tying an existing cavity wall by inserting a tie of the first aspect in a through-hole in one wall skin and a blind hole in the other wall skin so that there is a wall gripper in each said hole, and sequentially operating said wall grippers from the through-hole end.

Suitable wall grippers are of the spreading type, usually screw-operated, say by a nut on a threaded shank.

One preferred cavity wall tie hereof has threaded shanks, one at each end of a rod or spindle beyond abutments for spreadable sleeve parts of the grippers, and carrying nut-driven spreaders of which that at said other end can be located against rotation relative to its spreading sleeve and has an end or end-adjacent formation to bite in a blind hole and for operation by turning said rod or spindle, and that at said one end is for operation afterwards.

Said one end can have a flatted extension of its threaded shank for socket spanner turning of the spindle or otherwise be adapted for turning by a tool, say itself socketed for Allen-key operation. The preferred nut at that one end can then be of end-engageable, say slotted threaded collar form.

It will, of course, be appreciated that installation of a cavity wall tie, for the purposes hereof, is readily achieved only from one side of the wail concerned and without protrusion of the tie itself so that finishing off can be a simple matter of pointing.

For the rod or spindle interconnecting and carrying the wall grippers suitable water-passage prevention can be provided by a narrow medial enlargement that may further be of a size matching that of the aforesaid abutments, themselves preferably at least equal to unspread spreader sleeves. Then, usually with the medial enlargement closer to the abutment at the one end, installation of our preferred tie is facilitated by automatically guided first entry of the other end into the blind bore, i.e. after crossing the cavity, before the medial enlargement leaves the through hole.

Practical implementation of the invention will now be specifically described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a side view of a cavity wall tie hereof; Figure 2 shows an end view installation of that tie; Figure 3 shows installation of such a tie; and Figure 4 shows operating tools.

In the drawings, a particular tie hereof is shown in Figure 1 with two wall grippers 10 and 12, basically of the type using expansion sleeves 14, 16 spread by conical members 18,20 as the latter are driven into the sleeves 14,16. Until those sleeves 14,16 are spread sufficiently to grip surrounding material of a hole, abutments are required for the sleeves so that they do not simply shift with the conical members 18,20. Such abutments are shown at 22,24 on a rod or spindle 30 that interconnects the wall grippers 10, 12.

In fact, the expansion sleeves 14, 16 are on ends of the rod or spindle 30 that are externally threaded at least at suitable end portions 32, 34. One end (32) of the rod or spindle carries the spreading conical member 18 as a clearance, with a nut 36 engaging the spindle end threads in order to drive the conical member 18 in spreading the expansion sleeve 14.

The other end (34) of the rod or spindle carries the conical member 20 as a nut engaging its threads so that the number 20 can be driven in spreading the expansion sleeve 16 by holding the nut 20 and turning the spindle 30. To aid that for a blind hole accommodating the wall gripper 12, the free end 38 of the nut 20 is shown formed with blades or teeth to bite on the blind end of the aforesaid hole when pressure is applied to the rod or spindle 30 and that latter is turned by a tool engaging a flatted extension 40 of the rod or spindle 30. In practice, we find that teeth formations additionally or alternatively at the side of the end of the nut are effective, particularly so in relation to normal end-tapering of the blind hole resulting from conventional drill bits.A series of indentations inclined to the axis of the nut and through its end peripheral corner will suffice and can provide, by displacement of material, both side and end gripping teeth.

Once the nut 20 has started to spread the sleeve 16 into gripping engagement with material surrounding the blind hole, the nut 20 can no longer be pressed into biting engagement with the hole-end and is conveniently restrained from turning with the rod or spindle 30 by reason of the engagement with the sleeve 16. Such engagement may be assured beyond simple gripping action by suitable com plementaryformations, say pins and slots as shown for one such at 42,44 in the context of the well-known spreading (-leaf) Rawbolt-type devices (Rawbolt is a Registered Trade Mark). Other types of spreader sleeve type grippers could be used, e.g. of the deforming plastics type.

Medially of the rod or spindle 30, there is a narrow enlargment 46 to prevent water passage across the rod or spindle 30, any such water dripping off from the enlargement 46. It will be noted that the medial enlargement 46 and the abutment 22,24 are shown as matching the diameters of the wall grippers 10, 12 and such is advantageous for assisting installation by ensuring that the distance Xis at least equal to the width of the wall cavity. Then, the rod or spindle, particularly the nut 20, will be guided towards and into the blind hole as the enlargement 46 will not leave the through hole until the nut starts entry into the blind hole.

It is worth pointing out at this stage that none of the drawings is intended to be to scale, but only to be illustrative of the principle involved, especially as grippers may be proprietary items readily available.

Figure 3 shows an installed cavity wall tie of Figure 1 and 2 via a through-hole 50 in an outer wall skin 52 and a blind hole 54 in an inner wall skin 56 carrying interior plaster or other finishing 58.

Whilst the gripper 10 is intentionally located deep enough for the flatted extension 40 to be within the hole 50, thereby to aid finishing by pointing or plugging after installation, the actual position of the wall grippers 10 and 12 are to be taken as exemplary only. They could be at any operative position along their associated holes 50, 54. Also, of course, the water drip enlargement 46 need not be dead centre of the cavity 60.

In general, cavity wall ties as described will be of lengths and relative positions, sizes and types of parts as to suit particular wall constructions, loadings and materials.

Useful T-bartype socketed tools are shown in Figure 4 where 62 designates a tool (end view 62A) for the spindle extension 40 and 64 designates a tool (end view 64A) for the collar type nut 36.

Installation of a cavity wall tie hereof will normally proceed the following sequence of operations: (a) Making through-hole in one wall skin (usually, but not necessarily the outer skin) and a blind hole in the other wall skin, conveniently in a single drilling operation using a suitable power tool and drill bit.

Either or both of such holes may be through bodies of bricks or blocks or through mortar courses therebetween, say below a junction of two bricks in one course. Moreover, the holes need not be horizontal; (b) Inserting a cavity wall tie with its bit-enhanced nut end first; (c) Applying a tool such as 62 to the extension 40 with sufficient pressure for nut end 38 to bite on the end of the blind hole 54 and turning the spindle to expand the wall gripper 12 to the desired extent, even to a desired torque if desired; (d) Applying a tool such as 64to the nut 36 and turning same to expand the wall gripper 10 to the desired extent, also to a desired torque if required; (e) Filling the through-hole 50 to finish as desired.

Application of cavity wall ties of our invention to existing walls of suspect soundness regarding their cavity wall ties will insure against risk or failure for some considerable time, especially using corrosion resistant materials for parts of our ties or for coating or encasing parts of our ties.

The strengths of the various parts of our ties, and thus the materials used therefore, will be as per whatever specification is to be met, and such may well determine actual materials used, say the grade of a steel for the rod or spindle 30.

In general, however, materials for tie devices hereof and their parts should obviously be of adequate strength and resistance to corrosion. Stainless steel will certainly suffice, but other materials are not ruled out if they can be shown to perform satisfactorily.

Claims (15)

1. A cavity wail tie device comprising an elongate member carrying spaced wall grippers both operable from one end of said member, that furthest therefrom by rotation of said member and that closest thereto by rotation of a part on said member nearthat one end.

2. A tie device as claimed in claim 1, wherein the wall grippers are of the spreading type.

3. A tie device as claimed in claim 1 or 2, wherein the wall grippers are screw-operated relative to nuts on a threaded shank.

4. A tie device as claimed in any one of the preceding claims, having threaded shanks, one at each end of a rod or spindle beyond abutments for spreadable sleeve parts of the grippers, and carrying nut-driven spreaders of which that at said other end is locatable against rotation relative to its spreading sleeve by an end formation to bite in a blind hole and for operation by turning said rod or spindle, and that at said one end is for operation afterwards.

5. Atie device as claimed in claim 4, wherein said one end has a flatted extension of its threaded shank for turning of the spindle.

6. A tie device as claimed in claim 4, wherein said one end is socketed for Ailen-key turning of the spindle.

7. A tie device as claimed in claim 4, wherein the nut at that one end is end-engageable for turning on the spindle.

8. A tie device as claimed in any of the preceding claims, wherein water-passage prevention means are provided for the rod or spindle interconnecting and carrying the wall grippers.

9. A tie device as claimed in claim 8, wherein said water-passage prevention means comprises a narrow medial enlargement of the rod or spindle.

10. A tie device as claimed in claim 9 wherein the medial enlargement is of a size matching that of said abutments which are themselves of a size at least equal to unspread spreadable sleeve parts.

11. Atie device as claimed in claim 9 or 10, wherein the medial enlargement is closerto the abutment at the one end than at said other end.

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

13. A method of tying an existing cavity wall by inserting a tie device as claimed in any one of claims 1 to 12 in a through-hole in one wall skin and a blind hole in the other wall skin so that there is a wall gripper in each said hole, comprising the step of sequentially operating said wall grippers from the through-hole end.

14. A method as claimed in claim 13 using a tie device according to claim 8, wherein installation of the tie device is facilitated by the water passage prevention means serving to guide the tie device up to first entry of the other end into the blind bore.

15. A method of tying an existing cavity wall substantially as hereinbefore described with reference to the accompanying drawings.