GB2217766A - Wall tie - Google Patents

Abstract

First anchoring means (14), at the inner end of the wall tie in the cavity wall (50, 52), is mechanically expansible by rotation of the rod (10), e.g. to draw frusto-conical nut (26) into slotted metal sleeve (18), or in another version (not shown) to cause a compression nut to deform a compressible sleeve. Over-expansion of the relevant sleeve is prevented by breakage of the rod (10) at a break-off point (e.g. neck 44) near its outer end when a predetermined torque is applied. The break-off point is protected upon insertion of the wall-tie into the bore (54), which may involve tapping, by an overlying sleeve, preferably in the form of a cap nut (41). This sleeve is also adapted for engagement by the tool (48) for rotating the rod (10) and is removed and discarded along with the broken-off end portion (46). <IMAGE>

Description

WALL TIE This invention concerns wall ties of the kind comprising an elongate rod having first anchoring means, of mechanically-expansible nature, at or adjacent to one end thereof, for anchoring in one skin of a cavity wall, and second anchoring means (which may be of any suitable form) adjacent its other end for anchoring in the other skin of the wall, the arrangement being such that expansion of the first anchoring means is effected by rotation of the rod.

Wall ties of this sort are used, for example, as replacement for deteriorated or disintegrated wall ties in existing cavity walls, in order to ensure that the two skins of the wall remain tied to one another. Remedial work of this kind is becoming more and more necessary, especially in relation to building structures erected, for instance, thirty or forty years ago, when use was made extensively of galvanized wire butterfly-type wall ties in the original structure of the building, these wall ties having been prone to rusting away and disintegration, and thereafter resulting in bulging and/or cracking of the walls.

One of the problems in the installation of the replacement wall ties of the kind with which the invention is concerned is that excessive expansion of the anchoring means can result in bursting of the brick or other structural material of which the respective wall skin is constructed, with the result that the tie is not effectively anchored therein and does not perform its intended function.To ensure that the mechanically expansible first anchoring means is adequately expanded but not over-expanded, the applicants have proposed, in their prior UK Patent Application No. 2180568, that a wall tie of the kind defined in the first paragraph above, should be provided, at a location between the second anchoring means and the adjacent said other end of the rod, with a predetermined weakened, break-off point so that, upon rotation of said rod by application of force to said other end, the latter will break-off upon reaching a predetermined torque, thereby obviating the possibility of over-expansion of the first anchoring means. In this respect, the break-off point is conveniently provided by a reduced-diameter portion of the rod.

The present invention is a development of the applicants' aforesaid prior proposal, the wall tie now being additionally provided with a sleeve which is removably secured around the said other end of the rod so as to overlie the break-off point, and which is adapted to be directly engaged by a tool for effecting rotation of the rod and to be removed with said other end when it has been broken off.

The sleeve thus serves to protect the weakened breakoff point during installation of the wall tie and it also simplifies the installation procedure.

The sleeve is advantageously in the form of a cap having a closed end so that correct positioning thereof is simply determined by abutment of the inner end of the cap against the end of the rod. Also the sleeve is advantageously secured to the rod by mutually engageable screw threaded regions provided on the sleeve interior and on the rod. Furthermore, to enable secure engagement, e.g.

by a standard socket wrench, the sleeve preferably has a polygonal, e.g. square or hexagonal, external contour.

The mechanically expansible first anchoring means preferably comprises a tubular sleeve adapted to be expanded in a bore in the respective skin of the cavity wall. The sleeve may either be a metallic sleeve which is slotted along part of its length and is expanded by a frusto-conical nut being drawn therein by relative rotation between the rod and the nut, or it may be a deformable sleeve of plastics or rubber which is compressed, and thus expanded, by a nut at the one end of the rod being drawn towards an abutment at the opposite end of the sleeve by relative rotation between the rod and the nut. In either case, a further novel proposal is that the frusto-concial nut or the compression nut, respectively, is provided with lateral projections for ensuring that it is securely and non-rotatably located in the bore in the cavity wall.When such lateral projections (or ears) are provided on the nut at the one end (the inner end) of the wall tie, they prevent ready axial insertion of the wall tie into the bore. Consequently, the wall tie has to be tapped into place. During this operation there is clearly a risk of deformation at the weakened break-off point at the other end of the tie, so the protective sleeve or cap proposed in accordance with the invention assumes even greater importance.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:- Fig. 1 is a cross-sectional side elevation illustrating a first practical embodiment of the wall tie of the invention in position in a borehole in a cavity wall prior to expansion of the first anchoring means thereof; Fig. 2 is a view comparable with Fig. 1, but showing the wall tie with its first anchoring means fully expanded; Fig. 3 is an enlarged cross-sectional side elevation corresponding to the right-hand end of Figs. 1 and 2 and showing the wall tie with break-off point severed; Figs. 4 and 5 are views comparable with Fig. 3 illustrating expansion of the second anchoring means of the wall tie;; Fig. 6 is a cross-sectional side elevation illustrating a second practical embodiment of the wall tie of the invention in position if a respective borehole, with its first anchoring means fully expanded and its break-off point severed; and Fig. 7 is a view comparable with Fig. 6, but showing the wall tie with its second anchoring means fully expanded.

With reference to Figs. 1 and 2 the first embodiment of the wall tie of the invention comprises an elongate externally-threaded stainless steel rod 10 which has drip grooves 12 approximately midway along its length. At or adjacent one end of the rod 10 is first anchoring means, of a mechanically-expansible nature, as indicated generally by the reference numeral 14, and adjacent the other end of the rod 10 is second anchoring means indicated generally by the reference numeral 16.

The first anchoring means 14 comprises a tubular metal sleeve 18 the inner end of which abuts against a flanged collar 20 which in turn abuts against stop means provided by a shoulder 22 present at the root of a reduced-diameter externally screw-threaded end portion of the rod 10. Slots 24 are formed in the sleeve 18 and extend axially of the sleeve 18 from the end thereof remote from the washer 20 and over about half of the length of the sleeve 18. These slots 24 divide the respective end of the sleeve 18 into a plurality of fingers. A mechanical expansion element, in the form of a frusto-conical nut 26, is screwed onto the rod 10 so as to project by its narrow end into the sleeve 18. Around its wider end this nut 26 is provided with at least two equally spaced apart laterally projecting ears 27, which are formed integrally round the circumference of the nut 26. Upon rotation of the rod 10, the nut 26, is reliably retained against rotation by these ears 27 whilst the sleeve 18 is forced over the nut 26 and hence expanded.

The second anchoring means 16 is somewhat similar to the first anchoring means 14, but is reversed in its arrangement, comprising a sleeve 28, with slots 30, abutting by its non-slotted end against a collar 32 which in turn abuts against stop means provided by a shoulder 34 present at the root of a respective reduced diameter externally threaded end portion of the rod 10. A respective frusto-concial expansion element 36, slidable on the rod 10, projects by its narrow end into the slotted end of the sleeve 28 and is abutted by a nut 38 having, on its face averted from the expansion element 36, diametricallyopposed integral lugs or tongues 40 whereby the nut 38 can be rotated by means of a complementary tubular tool (See Figs. 4 and 5).

Formed in the rod 10, at a location between the second anchoring means 16 and the adjacent extremity 42 of the rod 10 , is a predetermined breaking-point provided by a reduced diameter portion 44 of the rod 10. This portion 44 defines a break-off portion 46 on the rod 10 at the end thereof remote from the first anchoring means 14. Located on the end margin of the rod 10, overlying the break-off portion 46 and extending beyond the reduced diameter portion 44, is a cap 41 having a sleeve portion and a closed end 43. The cap 41 has a hexagonal outer contour and the innermost part of its sleeve portion is internally threaded and in threaded engagement with the rod portion 46. The rod 10 can be rotated by application of torque to the cap 41 by a tool such as a convention type of socket wrench 48, as shown in Fig. 2.

The manner of operation and use of the wall tie will readily be understood from the foregoing description.

Where two skins 50, 52 of a cavity wall are to be tied together (e.g. in the event of disintegration or rotting away of a pre-existent wall tie, not shown) using the tie, firstly a bore 54 is bored into the skin of the wall, this bore 54 extending fully through the skin 50 (which may be the outer skin) and only part way into the skin 52 (which may be the inner skin). The assembled tie is then inserted into the bore 54 to the position shown in Fig. 1, in which the first anchoring means 14 is located wholly within the inner skin 52 and the second anchoring means 16 is located wholly within the outer skin 50. In view of the existance of the ears 27, such insertion is usually accomplished by tapping, i.e. application of blows to the outer end of the tie, namely the end 43 of the cap 41.In the course of insertion, the ears 27 cut grooves 51 in the wall of the bore 54, as indicated in Fig. 1 by dot-dash lines.

The rod 10 is now rotated by means of the tool 48, whilst the nut 26 is retained against rotation by frictional engagement of the ears 27 of the nut 26 with the wall of the bore 54 in the inner skin 52. As a result, the rod 10 passes threadedly through the nut 26 and the sleeve 18 is forced over the nut 26 and expanded such that it becomes firmly and reliably anchored in the inner skin 52, as shown in Fig. 2. When the sleeve 18 has been sufficiently expanded, the torque applied by means of the tool 48 will increase, and, dependent upon the dimensions chosen for the reduced diameter portion or neck 44, having regard to the strength of the material from which the rod 10 is made, in due time the neck 44 inside the cap 41 will break-off as has been shown in Fig. 3.This ensures that the anchoring device 14 will have been sufficiently expanded to assure proper anchorage in the inner wall skin 52, whilst avoiding too much expansion which might, for example, result in destruction or crumbling of the material of the inner skin 52.

The broken off end portion 46 of the rod 10 is still threadedly secured inside the cap 41 and can be discarded therewith.

The wall tie is subsequently anchored in the outer wall skin 50 by application of a suitable tool 58 to the nut 38 to engage with the integral lugs or tongues 40, as shown in Fig. 4, and to rotate the nut 38 and thereby expand the sleeve 28 by forcing the frusto-conical expansion element 36 therein. When a pre-determined torque value is achieved, the lugs or tongues 40 on the nut 38 yield as shown in Fig. 5, thus ensuring that the outer expansion element 16 is set at the correct torque value.

It will thus be appreciated that by the very simple expedient of locating the internally threaded cap covers 41 over the reduced-diameter portion or neck 44 on the rod 10 the latter is protected against premature breakage even when the wall tie has to be installed forcably by blows on its outer end. One also obtains the advantage that the larger diameter, more robust cap is more suitable than the end portion of the rod 10 (for gripping by conventionally sized wrenches and that the cap 41 can be removed with the broken off end portion 46 so that installation of the tie is not complicated by unscrewing operations to separate them.

After the second expansion element 16 has been secured by expansion, the end of the bore 54 can be plugged. The drip grooves 12 on the rod 10 have the effect of preventing moisture from moving across the rod 10 between the two skins 50, 52 of the wall.

Turning now to Figs. 6 and 7, the second illustrated embodiment of the wall tie of the invention comprises an elongate relatively large diameter stainless steel rod 100 which has drip grooves 102 approximately midway along its length. At or adjacent one end of the rod 100 is first anchoring means, of a mechanically-expansible nature, as indicated generally by the reference numeral 104, and adjacent the other end of the rod 100 is second anchoring means indicated generally by the reference numeral 118.

The first anchoring means 104 comprises an abutment in the form of a thick washer 106 which is located on an externally-threaded reduced diameter end portion 108 of the rod 100. The washer 106 is located at a predetermined position spaced away from the adjacent rod end by abutting against a shoulder occurring at the root of the threaded end portion 108, where the latter joins with the adjacent externally-smooth thicker portion of the rod 100. The anchoring means 104 further includes a deformable tubular sleeve 110, of neoprene rubber, which internally is snug fit upon the rod portion 108 and externally is of a selected diameter, for instance of the order of 12 or 13mm, and a compressing nut 112 which abuts the end of the sleeve 110 remote from the abutment washer 106. This nut 112 has a radial array of teeth 114 formed in its surface facing the sleeve 110, for gripping said sleeve 110 non-rotatably.

It also has at least two laterally projecting ears 116 around its circumference.

The second anchoring means 118 is similar to the first anchoring means 104 but is effectively reversed in its arrangement. It comprises a thick abutment washer 120 located on a respective reduced-diameter externallythreaded end portion 122 of the rod 100, against movement in a direction towards the first anchoring means 104 by abutting against a shoulder which occurs at the root of the threaded end portion 122. A deformable tubular sleeve 126, of neoprene rubber, which is similar to the sleeve 110, abuts the washer 120 and in turn is abutted by a respective compressing nut 128, by way of a washer 130. The nut 128 is of circular external configuration and bearing lugs or tongues 132 by which it can be engaged by a tubular spanner 134 (See. Fig. 7)for rotating it.

Provided in the threaded end portion 122 of the rod 100, between the second anchoring means 118 and the adjacent extremity of the rod 100 there is a narrowed neck 136 which constitutes a predetemined breaking point and which defines, on the respective end portion 122 of the rod 100, a terminal break-off portion 138. Located on the end margin of the rod 100 overlying the break-off portion 138 and extending beyond the neck 136, is a cap 140 in the form of a sleeve having a closed end 142. the cap has a hexagonal external contour and internally it is threadedly engaged with the rod break-off portion 138. The rod 100 can be rotated by application of torque to the cap 140, by a tool such as a conventional wrench 144, as shown in Fig.

6.

The method of installation of this embodiment of the wall tie of the invention in a cavity wall is similar to that of Figs. 1 to 5 as described above. Firstly, an appropriate hole 154 is bored into the wall so that it extends through one skin 150 (which may be the outer skin) of the wall and extends a predetermined distance into, but not right through, the other skin 152 (which will then be the inner skin of the wall). This hole 154 is such that the neoprene sleeves 110, 126 are a close sliding fit thereon and the tie is inserted with its components all assembled. In view of the presence of the ears 116 on the compression nut 112, the tie is usually be pushed fully home by tapping, i.e. by application of the blows to the outer end of the tie, namely the end 142 of the cap 140.

In the course of insertion, the ears 116 form shallow grooves in the wall of the hole 154, but these are not illustrated.

The tool 144 is then applied to the cap 140, which is secured to the rod 100, and the latter is turned to rotate the rod 100. The frictional engagement between the ears 116 of the nut 112 and the wall of the hole 154 prevents the nut 112 rotating and as its teeth 114 grip into the sleeve 110 the latter is also inhibited from rotating. As a result, the threaded end portion 108 of the rod 100 is wound through the nut 112 thus forcing the abutment washer 106 towards the nut 112 and compressing the sleeve 110 axially therebetween causing it to expand radially to anchor the first expansion means 104 in the inner wall skin 152. When the sleeve 110 has been sufficiently expanded, the rod section 138, which is secured inside the cap 140, breaks off at the neck 136 and can be discarded together with the cap 140 (i.e. without detachment therefrom). This is illustrated in Fig. 6.

Subsequently, the tool 134 is applied to the nut 128, to turn the latter to cause axial compression of the sleeve 126 with corresponding radial expansion of the latter to anchor it in the outer wall skin 150. The lugs or tongues 132 yield when the sleeve 126 has been sufficiently expanded. This illustrated in Fig. 7.

Thus, once again, by the very simple expedient of locating the cap 140 over the neck 136 of the rod 100, the latter is protected against premature breakage or other damage during installation.

The invention is not confined to the precise details of the foregoing examples and variations may be made thereto. Thus, although in the illustrated examples both first and second anchoring have been shown to be mechanically expansible and of the same type (i.e. slotted metal sleeves or compressible neoprene sleeves), in other embodiments one of each type may be present, and, indeed, since it is only essential for the first anchoring means to be mechanically expansible the second anchoring means may be secured in the outer skin of the cavity wall only by adhesive means, e.g. cement or resin.

Furthermore, where the first anchoring means is a deformable sleeve, it need not be of neoprene rubber and could be of any suitable plastics or other material. Also, the compression nut may be adhesively bonded to said sleeve instead of having teeth for gripping thereagainst.

Many other minor variations in form are possible.

Claims (11)

1. A wall tie of the kind comprising an elongate rod having first anchoring means, of mechanically-expansible nature, at or adjacent to one end thereof, for anchoring in one skin of a cavity wall, and second anchoring means adjacent its other end for anchoring in the other skin of the wall, the arrangement being such that expansion of the first anchoring means is effected by rotation of the rod, a pre-determined break-off point being provided at a location between the second anchoring means and the adjacent said other end of the rod so that, upon rotation of said rod by application of force to said other end, the latter will break-off upon reaching a predetermined torque, characterised in that a sleeve is removably secured around the said other end of the rod so as to overlie the break-off point, which sleeve is adapted to be directly engaged by a tool for effecting rotation of the rod and to be removed with said other end when it has been broken off.

2. A wall tie as claimed in claim 1 wherein the breakoff point is provided by a reduced diameter portion of the rod.

3. A wall tie as claimed in claim 1 or 2 wherein the sleeve is in the form of a cap having a closed end for abutment against the end of the rod.

4. A wall tie as claimed in claim 1, 2 or 3 wherein the sleeve is secured to the rod by mutually engageable screw threaded regions provided on the sleeve interior and on the rod.

5. A wall tie as claimed in any preceding claim wherein the sleeve has a polygonal external contour.

6. A wall tie as claimed in any preceding claim wherein the first anchoring means comprises a tubular sleeve adapted to be expanded in a bore in the respective skin of the cavity wall.

7. A wall tie as claimed in claim 6 wherein the sleeve is a metallic sleeve which is slotted along part of its length and is expanded by a frusto-conical nut being drawn therein by relative rotation between the rod and the nut.

8. A wall tie as claimed in claim 6 wherein the sleeve is a deformable sleeve of plastics or rubber which is compressed, and thus expanded, by a nut at the one end of the rod being drawn towards an abutment at the opposite end of the sleeve by relative rotation between the rod and the nut.

9. A wall tie as claimed in claim 7 or 8 wherein the frusto-conical nut or the compression nut, respectively, is provided with lateral projections adapted for non-rotatably engaging in the bore in the cavity wall.

10. A wall tie as claimed in any preceding claim wherein the second anchoring means also comprises a mechanically expansible sleeve, and a nut which is threadedly engaged on the rod and is rotatable to effect expansion of the sleeve, the nut having integral lugs or tongues which are engageable by a tool for rotation of the nuts and which are adapted to yield on application of a pre-determined torque.

11. A wall tie substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 5, or Figs. 6 and 7 of the accompanying drawings.