GB2118234A

GB2118234A - Cavity wall tie for existing walls

Info

Publication number: GB2118234A
Application number: GB08208459A
Authority: GB
Inventors: Ian Ross Adam; James Mallon
Original assignee: Phillips Drill Co Inc
Current assignee: Phillips Drill Co Inc
Priority date: 1982-03-23
Filing date: 1982-03-23
Publication date: 1983-10-26
Also published as: GB2118234B

Abstract

Leaves 2,3 of a cavity wall are tied by stainless steel tie rod 1 inserted into bores 5,4 in the leaves. Tie rod 1 is secured in the innermost (blind) bore 4 by sleeve 11, which radially expands upon axial compression, on a threaded end of the tie rod between a stop member 8 fast with the rod and a threaded nut 15. Friction rings 12,14 provide that there is a higher frictional connection between the sleeve and the nut 15 than the sleeve and the stop member 8 at least during installation of the tie rod. To secure the rod (1) in the bore (4), the sleeve is pre-expanded, before insertion, so that frictional engagement of the sleeve with the bore is provided by screwing the nut towards the stop member. After insertion, further expansion of the sleeve 11 is obtained by rotating the rod, e.g. by tool 22,23, since nut 15 is frictionally connected to sleeve 11, which is itself prevented from rotation by frictional engagement with the bore. <IMAGE>

Description

SPECIFICATION Cavity wall tie This invention relates to anchoring devices such as cavity wall ties which are inserted to tie the leaves of a cavity wall together subsequently to the building thereof, and in particular but not exclusively to remedial cavity wall ties for replacing wall ties employed when the wall was built which have since corroded.

There are many known mechanical remedial cavity wall tie arrangements. In our co-pending Application No. 8035638 (Serial No. ) (J.R. Adam-J. Mallon 18-1) various mechanical remedial cavity wall tie arrangements are disclosed. These ties comprise threaded rods and employ expandible elements, adjacent one or each wall leaf, comprising, for example, a cylindrical sleeve of plastics material such as polyvinyl chloride which can be axially compressed and thus radially expanded by means of a nut screwed along the rod by a tubular spanner. A through hole and a blind bore are first drilled into the near far leaves of the wall, respectively.The rod carrying one expandible element is inserted into the blind bore via the through hole, and the one expandible element is expanded, by use of a tubular spanner extending through the near leaf and cavity and into the blind bore, to engage the far leaf. A drop ring is positioned on the rod between the leaves. Another expandible element is assembled onto the rod and expanded to engage the near leaf. A portion of the rod thread adjacent the cavity side of the near leaf is distorted to ensure that the other expandible element is correctly positioned relative to the near leaf.

According to one aspect of the present invention there is provided a cavity wall tie comprising a rod whose first and second ends are to be secured in respective bores in the separate leaves of a cavity wall, the first rod end being threaded, and an anchoring device for the first rod end including an internallythreaded member adapted for screwing on the first rod end, a stop member to be secured to the first rod end, a sleeve element, which is radially expandible upon axial compression, for arrangement on the first rod end between the internally-threaded member and the secured stop member, and means whereby there is a higher frictional connection between the internally-threaded member and the sleeve element than between the stop member and the sleeve element such that during installation of the wall tie radial expansion of the sleeve element, for anchoring the first rod end in the respective bore, can be achieved by rotation of the rod.

According to another aspect of the present invention there is provided a cavity wall tie for installation between the leaves of a cavity wall, one leaf having a blind bore communicating with the cavity between the wall leaves and the other leaf having a through bore in alignment with the blind bore, the wall tie including a tie rod with first and second ends, the first rod end being threaded and provided with an anchoring device whereby to secure it in the blind bore; the anchoring device comprising a sleeve element, which expands radially upon axial compression, arranged on the first rod end between a stop member secured to the first rod end and an internally-threaded member screwed onto the first rod end, means being provided such that there is a higher frictional connection between the internally-threaded member and the sleeve element than between the sleeve element and the stop member, at least during wall tie installation; the second rod end being provided with means whereby to anchor it in the through bore subsequently to the anchoring of the first rod end in the blind bore; and wherein in use of the tie, and before insertion into the bores, the sleeve element is radially pre-expanded, by screwing the internallythreaded member towards the stop member, to provide frictional contact with the blind bore upon insertion therein, and wherein after insertion further expansion of the sleeve element in the blind bore, whereby to secure the first rod end therein, is achieved by reducing the distance between the internally-threaded member and the stop member by rotation of the rod by means applied at the second rod end.

Embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows, schematically, a section through a cavity wall whose leaves are tied together by a wall tie according to one embodiment of the present invention, and Figure 2 shows an alternative expandible element arrangement for the blind bore in the far wall leaf.

In the embodiment of the present invention shown in Fig. 1, a stainless steel tie rod 1 is secured to both leaves 2 and 3 of a cavity wall. Generally leaf 2 will be the inner leaf and leaf 3 the outer leaf, since in existing buildings it is normally preferable to drill from the outside in rather than vice versa, although alternatively leaf 2 may be the outer leaf and leaf 3 the inner leaf. Wall leaf 2 is provided with a blind bore 4 and wall leaf 3 is provided with a through bore 5. Through bore 5 is drilled first and subsequently blind bore 4 is drilled through bore 5 so that bores 4 and 5 are aligned. The rod 1 is threaded over its entire length or alternatively, and as shown, its centre section may be unthreaded.

Prior to insertion in the bores 4 and 5 the tie rod 1, expandible elements and associated components, and a drip ring 7 are assembled together to form a tie assembly. The expandible elements and associated components asso ciated with the inner leaf 2 comprise a nut 8, which is locked to rod 1 for rotation therewith at the axial position shown that in use of the tie assembly is adjacent the cavity 9 between the wall leaves 2 and 3; a washer 10; an expandible element 11 comprising a cylindrical sleeve of plastics material, for example, polyvinyl chloride; a friction washer 12; a washer 13; a friction washer 1 4 and a nut 15.The nut 8 may be locked to the rod 1 as a result, for example, of the threaded portion 1 6 of the rod having been distorted so as to prevent the nut passing beyond that portion along the rod, particularly if the rod is threaded along its entire length. The expandible element and associated components associated with wall leaf 3 comprise a nut 17, which is locked to the rod 1 at the axial position shown that in use of the tie assembly is adjacent the cavity 9; a washer 18; an expandible element 1 9 also comprising a cylindrical plastics element of polyvinyl chloride; a washer 20 and a nut 21. Drip ring 7 is positioned between the two expandible elements such as to be arranged centrally within cavity 9 and may be in the form of a resilient ring element made, for example, of rubber or neoprene, and a tight fit on the rod.The drip ring 7 serves to prevent the passage of moisture from one wall leaf to the other via the rod 1.

To use the tie assembly the sleeve element 11 is pre-expanded slightly by screwing the nut 1 5 further onto rod 1 whereby when inserted in blind bore 4 there is friction grip between the sleeve element 11 and the wall of bore 4. An internally-threaded stud driver sleeve 22, having spanner flats or a hexagonally cross-sectioned shape and with a stud driver threaded bolt 23 screwed partially thereinto, is screwed onto the end of rod 1 adjacent nut 21 to the extent permitted by bolt 23, thus locking stud driver sleeve 22 to rod 1. The tie assembly and stud driver is then ready for insertion into bores 4 and 5.

To secure such an inserted assembly to the wall leaves 2 and 3, the stud driver sleeve 22 is rotated by a standard spanner, thus rotating rod 1. The nut 8 is locked to rod 1 and turns therewith but the expandible sleeve element 11 does not turn due to the effect of friction between it and the wall of bore 4. The washer 1 3 is effectively locked to the sleeve element 11 by the friction washer 1 2 and locked to the nut 1 5 by the friction washer 1 4. Thus as the sleeve 22 is rotated, the rod 1 rotates within nut 1 5 and, with rotation in the direction to pull nut 1 5 further on to rod 1, the sleeve element 11 is further axially compressed and correspondingly radially expanded to lock it to the leaf 2.The friction between the nut 8 and its associated washer 10 is low so that the nut can rotate freely with respect the washer. Thus the inner expandible sleeve element 11 is locked to the inner leaf without the need for a special tubular spanner as required with the tie arrangements described in our above-mentioned co-pending application.

When the sleeve 11 is firmly locked in position as, for example, proved by application of a torque wrench to stud driver 22, the stud driver 22 and bolt 23 are removed and the expandible sleeve element 1 9 is expanded, whereby to lock it to the leaf 3, by means of a box key or slotted screw driver applied to nut 21; nut 17 being locked to the rod. The plain washers 10, 14, 1 8 and 20 serve primarily to assist the axial compression and confine the radial expansion of the sleeve elements 11 and 19, whereby to maximise the locking effect between the sleeve elements and the respective leaves.

In the event that the sleeve 11 cannot be firmly locked in position, the assembly may be withdrawn and employed in another hole.

Once a tie is locked to both wall leaves the mouth of the bore 5 may be filled with mortar.

In particular in cases where the wall leaf 3 is of a low grade material, it may be alternatively preferable to use a resin-grout fixing of the rod to the wall leaf 3, such as is described in our co-pending Application No. 81 34892 (Serial No. ) (l.R. Adam-J. Mallon 20-3). Whereas the anchoring of the tie rod in leaf 3 has been described with reference to a sleeve radially expandible by axial compression, other expandible arrangements may alternatively be employed.

The use of a standard spanner rather than a special tubular spanner is enabled by creating high friction between the nut 1 5 and the sleeve 11, with low friction at the nut 8 which is locked to rod 1, so that the sleeve 11 can be expanded by rotation of the rod 1 itself, which rotation may be effected from a position externally of wall leaf 3, and thus can be achieved by a standard spanner. Instead of nut 1 5 and washers 12, 1 3 and 14, a single internally-threaded collar 24 (Fig. 2) with a roughened, high friction face 26 adjacent sleeve 11 can be used. In use the collar 24 is effectively locked to the sleeve 11 during rotation of rod 1 and thus drawn further thereonto whereby to radially expand the sleeve 11. The collar 24 of Fig. 2 functions as both the nut 15 and the washer 13 of Fig. 1.

Whereas the "locked" nut 8 is described above as being innermost on the rod 1 relative to the nut 15, alternatively the "locked" nut 8 may be at the end of rod 1 and the nut 1 5 and its associated friction washers etc.

may be innermost.

The tie assemblies of the present invention, particularly that described with respect to Fig.

1, are of very low cost relative to the hitherto known mechanical arrangements since they use entirely standard nuts, washers, threaded rods etc. The length of the overall tie assem bly can easily be varied, simply by changing the length of threaded studding used for the rod 1. The tie assemblies may be supplied fully assembled, comprising the expandible elements with associated components, together with a drip ring on a rod, so that the actual installation is very fast and simple.

Alternatively the various piece parts may be supplied for assembly by the installer prior to installation, in any event in the case of mechanical gripping at both rod ends the fully assembled tie is inserted into the bores as a single unit and it is not required to fit the drip ring or outermost expandible element onto the rod part way during the installation procedure.

Claims

1. A cavity wall tie comprising a rod whose first and second ends are to be secured in respective bores in the separate leaves of a cavity wall, the first rod end being threaded, and an anchoring device for the first rod end including an internally-threaded member adapted for screwing on the first rod end, a stop member to be secured to the first rod end, a sleeve element, which is radially expandible upon axial compression, for arrangement on the first rod end between the internallythreaded member and the secured stop member, and means whereby there is a higher frictional connection between the internallythreaded member and the sleeve element than between the stop member and the sleeve element such that during installation of the wall tie radial expansion of the sleeve element, for anchoring the first rod end in the respective bore, can be achieved by rotation of the rod.

2. A cavity wall tie as claimed in claim 1, wherein the frictional connection means comprise friction washer means for arrangement between the internally-threaded member and the sleeve.

3. A cavity wall tie as claimed in claim 2, including respective plain washers for the sleeve element ends and respective friction washers for arrangement between the internally-threaded member and the associated plain washer, and between the said associated plain washer and the sleeve element.

4. A cavity wall tie as claimed in claim 1, wherein the frictional connection means comprises a roughened high friction end face of the internally-threaded member.

5. A cavity wall tie as claimed in any one of the preceding claims further comprising an anchoring device for the second rod end, which second rod end is threaded including a further stop member to be secured to the second rod end adjacent the cavity between the leaves, a further internally-threaded member adapted for screwing on the second rod end, a further sleeve element, which is radially expandible upon axial compression, for arrangement on the second rod end between the further stop member and the further internally-threaded member, and wherein during installation the further sleeve element is radially expanded, after expansion of the sleeve element associated with the first rod, by screwing the further internally-threaded member towards the further stop member.

6. A cavity wall tie as claimed in any one of claims 1 to 4, wherein the second rod end is adapted for securement in the respective bore by resin grouting.

7. A cavity wall tie as claimed in any one of the preceding claims for installation with the first anchoring device in a blind bore and the second rod end extending in a through bore of the respective leaves of the cavity wall, the second rod end being such that the rod can be rotated by means applied at the second rod end whereby to radially expand the sleeve element of the first anchoring device at the first rod end.

8. A cavity wall tie as claimed in any one of the preceding claims including a drip ring for arrangement on the tie rod between the first and second ends thereof.

9. A cavity wall tie for installation between the leaves of a cavity wall, one leaf having a blind bore communicating with the cavity between the wall leaves and the other leaf having a through bore in alignment with the blind bore, the wall tie including a tie rod with first and second ends, the first rod end being threaded and provided with an anchoring device whereby to secure it in the blind bore; the anchoring device comprising a sleeve element, which expands radially upon axial compression, arranged on the first rod end between a stop member secured to the first rod end and an internally-threaded member screwed onto the first rod end, means being provided such that there is a higher frictional connection between the internally-threaded member and the sleeve element than between the sleeve element and the stop member, at least during wall tie installation; the second rod end being provided with means whereby to anchor it in the through bore subsequently to the anchoring of the first rod end in the blind bore; and wherein in use of the tie, and before insertion into the bores, the sleeve element is radially pre-expanded, by screwing the internally-threaded member towards the stop member, to provide frictional contact with the blind bore upon insertion therein, and wherein after insertion further expansion of the sleeve element in the blind bore, whereby to secure the first rod end therein, is achieved by reducing the distance between the internally-threaded member and the stop member by rotation of the rod by means applied at the second rod end.

10. A cavity wall tie as claimed in claim 9, including a drip ring arranged on the rod between the ends thereof such as to be positioned in the cavity after installation of the tie.

11. A cavity wall tie as claimed in claim 9 or 10, wherein the second rod end is threaded and the anchoring means therefor comprises a respective sleeve element, which expands radially upon axial compression, arranged on the second rod end between a stop member, secured to the second rod end whereby to be in the through bore and adjacent the cavity after installation of the tie, and a respective internally-threaded member screwed on the second rod end, and wherein in use of the tie, and subsequently to the anchoring of the first rod end in the blind, the sleeve element of the second rod end in the through bore, by screwing the respective internally-threaded member towards the respective stop member.

1 2. A cavity wall tie as claimed in any one of the preceding claims wherein the rod is of stainless steel.

1 3. A cavity wall tie as claimed in any one of the preceding claims wherein the or each sleeve element is of polyvinyl chloride.

14. A cavity wall tie as claimed in any one of the preceding claims wherein the rod is of stainless steel.

1 5. A cavity wall tie as claimed in any one of the preceding claims wherein the or each expandible element is a sleeve of polyvinyl chloride.

1 6. A cavity wall tie substantially as herein described with reference to and as illustrated in Fig. 1 or Fig. 2 of the accompanying drawings.

1 7. An anchor comprising rod having a first end to be secured in a wall, the first end being threaded, and an anchoring device for the first rod end including an internallythreaded member adapted for screwing on the first end, a stop member on the first end and an element of deformable material which is radially expandible upon axial compression between the stop member and the threaded member, and means providing higher frictional connection between the internallythreaded member and the expandible element than between the expandible element and the stop member, such that during installation of the anchor radial expansion of the expandible element can be achieved by rotation of the rod.

14. A cavity wall tie substantially as herein described with reference to and as illustrated in Fig. 1 or Fig. 2 of the accompanying drawings.

1 5. An anchor comprising a rod having a first end to be secured in a wall, the first end being threaded, and an anchoring device for the first rod end including an internallythreaded member adapted for screwing on the first end, a stop member on the first end and a sleeve of deformable material which is radially expandible upon upon axial compression between the stop member and the threaded member, and means providing higher frictional connection between the internallythreaded member and the sleeve than between the sleeve and the stop member, such that during installation of the anchor radial expansion of the sleeve can be achieved by rotation of the rod.

CLAIMS (14 Mar 1983)

1. A cavity wall tie comprising a rod whose first and second ends are to be secured in respective bores in the separate leaves of a cavity wall, in the first rod end being threaded, and an anchoring device for the first rod end including an internally-threaded member adapted for screwing on the first rod end, a stop member to be secured to the first rod end, an element, which is radially expandible upon axial compression, for arrangement on the first rod end between the internallythreaded member and the secured stop member, and means whereby there is a higher frictional connection between the internallythreaded member and the expandible element than between the stop member and the expandible element such that during installation of the wall tie radial expansion of the expandible element, for anchoring the first rod end in the respective bore, can be achieved by rotation of the rod.

2. A cavity wall tie as claimed in claim 1, wherein the frictional connection means comprise friction washer means for arrangement between the internally-threaded member and the expandible element.

3. A cavity wall tie as claimed in claim 2, including respective plain washers for the expandible element ends and respective friction washers for arrangement between the internally-threaded member and the associated plain washer and between the said associated plain washer and the expandible element.

5. A cavity wall tie as claimed in any one of the preceding claims, wherein the expandible element is a sleeve element.

6. A cavity wall tie as claimed in any one of the preceding claims further comprising an anchoring device for the second rod end, which second rod end is threaded, including a further stop member to be secured to the second rod end adjacent the cavity between the leaves, a further internally-threaded member adapted for screwing on the second rod end, a further element, which is radially expandible upon axial compression, for arrangement on the second rod end between the further stop member and the further internally-threaded member, and wherein during installation the further expandible element is radially expanded, after expansion of the expandible element associated with the first rod end, by screwing the further internallythreaded member towards the further stop member.

7. A cavity wall tie as claimed in claim 6 wherein the further expandible element is a sleeve element.

8. A cavity wall tie as claimed in any one of claims 1 to 5, wherein the second rod end is adapted for securement in the respective bore by resin grouting.

9. A cavity wall tie as claimed in any one of the preceding claims for installation with the first rod end anchoring device in a blind bore and the second rod end extending in a through bore of the respective leaves of the cavity wall, the second rod end being such that the rod can be rotated by means applied at the second rod end whereby to radially expand the expandible element of the anchoring device at the first rod end.

10. A cavity wall tie as claimed in any one of the preceding claims including a drip ring for arrangement on the rod between the first and second ends thereof.

11. A cavity wall tie for installation between the leaves of a cavity wall, one leaf having a blind bore communicating with the cavity between the wall leaves and the other leaf having a through bore in alignment with the blind bore, the wall tie incuding a tie rod with first and second ends, the first rod end being threaded and provided with an anchoring device whereby to secure it in the blind bore; the anchoring device comprising an element, which expands radially upon axial compression, arranged on the first rod end between a stop member secured to the first rod end and an internally-threaded member screwed onto the first rod end, means being provided such that there is a higher frictional connection between the internally-threaded member and the expandible element than between the expandible element and the stop member, at least during wall tie installation; the second rod end being provided with means whereby to anchor it in the through bore subsequently to the anchoring of the first rod end in the blind bore; and wherein in use of the tie, and before insertion into the bores, the expandible element is radially pre-expanded, by screwing the internally-threaded member towards the stop member, to provide frictional contact with the blind bore upon insertion therein, and wherein after insertion further expansion of the expandible element in the blind bore, whereby to secure the first rod end therein, is achieved by reducing the distance between the internally-threaded member and the stop member by rotation of the rod by means applied at the second rod end.

1 2. A cavity wall tie as claimed in claim 11, including a drip ring arranged on the rod between the ends thereof such as to be positioned in the cavity after installation of the tie.

1 3. A cavity wall tie as claimed in claim 11 or 12, wherein the second rod end is threaded and the anchoring means therefor comprises a respective element, which expands radially upon axial compression, arranged on the second rod end between a stop member, secured to the second rod end whereby to be in the through bore and adjacent the cavity after installation of the tie, and a respective internally-threaded member screwed on the second rod end, and wherein in use of the tie, and subsequently to the anchoring of the first rod end in the blind bore, the expandible element of the second rod end anchoring means is expanded, whereby to secure the second rod end in the through bore, by screwing the respective internally-threaded member.