GB2143571A

GB2143571A - Tie for existing cavity wall

Info

Publication number: GB2143571A
Application number: GB08318420A
Authority: GB
Inventors: Ronald James Millen
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-07-07
Filing date: 1983-07-07
Publication date: 1985-02-13
Also published as: GB8318420D0; GB2143571B

Abstract

Rod 4 carrying two spaced spreadable gripping devices 13 and 14 is inserted into bores 23 and 24 in inner and outer wall skins 2 and 3. The rod 4 has screw-threaded portions 5 and 6 at its ends and a pair of flats 7 at one end forming a tongue. On portion 6 are mounted abutment 9 and nut 16 with a frusto-conical surface and lugs 21. On nut 16 are mounted gripping members 12 whose inner surfaces form a complementary frusto- conical contact surface and which have outer bore-engaging bosses 20. On portion 5 are mounted an abutment 8 and nut 15 with a frusto-conical surface, and slot 29. On nut 15 also are frusto-conical gripping members 12. Rod 4 is rotated by the tongue. Nut 16 is prevented from rotation by gripping members 12 and bosses 20, so that it moves towards abutment 9 and spreads gripping members 12 against the bore. When the rod is secure, nut 15 is rotated by slot 29 and moves towards abutment 8, spreading gripping members 12 against the bore. <IMAGE>

Description

SPECIFICATION Tie The present invention relates to a tie particularly though not exclusively for use as a wall tie.

Modern brick walls are built as two skins with a cavity therebetween. The two skins are tied together by a regular array of wall ties.

These may be in the form of galvanised steel stampings of galvanised wire. Despite the galvanising, wall ties do not last indefinitely and can rust and fail after some fifty years.

When they do fail, the outer wall of a house may bulge outwards. If this bulging is not checked, the house may ultimately collapse.

The conventional method of repairing a house with failed wall ties is to cut out sufficient outside bricks to give access to the cavity, cement a wall tie into the inner skin and replace the outside bricks. Wall ties are normally positioned at horizontal spacings of 900 mm and vertical spacings of 450 mm.

Six bricks normally require removal and replacement for insertion of one new wall tie.

Thus repairing of a wall requires a very considerable amount of work. Not only does the outer skin require this removal and replacement, but the inner skin is disturbed, usually requiring replastering and redecorating.

Expanding nuts are known which either comprise a spreading member which is tapered and urges radially outwards gripping members or comprisea unitary member adapted to spread outwards itself on tightening. For tying together two wall skins it is essential that the replacement tie is known to be fixed in both skins. If two expanding bolts were arranged back-to-back and tightened it could happen that the bolt in the outer skin locks and prevents further tightening before the bolt in the inner skin tightens.

The object of the present invention is to provide a tie which can be tightened in one member and subsequently tightened in another member to be tied to the first member.

According to the invention there is provided a tie comprising a pin having two spaced abutments intermediate its ends and being adapted at one end to be turned about its central longitudinal axis, one radially spreadable nut screwedly attached to the one end of the pin and another radially spreadable nut screwedly attached to the other end of the pin, the arrangement being such that the said other radially spreadable nut is adapted to be spread on turning of the pin via the said adaption of the one end and the said one radially spreadable nut is adapted to be spread by turning of a spreading member thereof on the pin.

On the one hand, the said other spreadable nut may be either of the type having a spreading member and separate gripping members or of the type having a unitary member which is threaded and is adapted to spread outwards on tightening, since the nut is tightened by turning of the pin with little or no rotation of the nut in its bore. To assist initial setting of the nut in the bore, the gripping members, or their equivalent in a unitary nut, are prefferably provided with bore engaging bosses. On the other hand, the said one spreadable nut is preferably of the type having a spreading member and separate gripping members whereby turning of the spreading member on the pin allows tightening of the nut without rotation of the gripping members in the bore.

When both nuts are of the type having separate spreading members, they nevertheless differ in that whilst the spreading member of the one nut turns with respect to its gripping members, the spreading member of the other nut is held from rotation by its gripping members.

According to another aspect of the invention, there is provided a method of tying together two spaced structural members with a tie in accordance with the first aspect of the invention, the method consisting in the steps of: boring through the first structural member into the second structural member, the resultant bores in the two members being aligned; inserting the tie into the bores to such extent that the one radially spreadable nut is in the bore in the first structural member and the other radially spreadable nut is in the bore in the second structural member; turning the pin of the tie via the adaption of its one end to spread the other radially spreadable nut to secure the tie in the second structural member; and once the said other nut is thus secured turning the spreading member of the one radially spreadable nut on the now secured pin to spread the one radially spreadable nut to secure the tie in the first structural member thereby tying together the two structural members.

Preferably the gap between the structural members will correspond to the gap between the abutments on the pin. Additionally, the length of the pin from its abutments to its respective ends is preferably less than the thickness of the structural members whereby the tie does not remain exposed after fitting to the structural members.

The tie may be used for tying onto a building pre-cast concrete facing panels. Alternatively it may be used for tying together the skins of a cavity wall. In this use it is preferably installed at a mortar joint between individual bricks and/or blocks, although it may be installed by boring through bricks themselves.

Where it is installed in a mortar joint, the bore left outside the one end of the tie is preferably filled with mortar leaving a neat appearance.

It will be appreciated that the installation of the tie requires only minimal local disturbance of the wall. To make the tie resistant to rusting it is either made of stainless steel, or when of mild steel it is encased in shrink-on plastics material tube.

To help understanding of the invention, a specific embodiment thereof will now be described with reference to the accompanying drawing in which: Figure 1 is a central, longitudinal, crosssectional view of a tie in accordance with the invention installed in a cavity wall, and Figure 2 is a cross-section on the line ll-ll in Figure 1 of the tie alone.

The tie 1 is shown in Figure 1 tying together the two skins 2,3 of the cavity wall. A pin 4 of the tie has threaded ends 5,6, one 5 of which has at its extremity a pair of flats 7 via which the pin is turnable. A pair of abutments 8,9 are screwed onto the pin and are locked against the inner extents of the screw threads, with a plain threadless-middle portion 10 of the pin between the abutments.

These have counterbores 11 in their faces facing away from each other. Engaged in the counterbores are toes of gripping members 1 2 of radially spreadable nuts 1 3,1 4 on the ends 5,6 of the pin. The nuts have spreading members 1 5,1 6 threadedly engaged on the pin. For holding the gripping members together prior to fitting, each nut 1 3,1 4 has a spring ring 1 7 extending around the gripping members and engaging in grooves 1 8 in the spreading members 1 2. The spreading members 1 5,1 6 taper towards the middle of the tie.The gripping members 1 2 have inner surfaces 1 9 in contact with the spreading members which are shaped complementarily thereto.

The radially spreading nuts 13,14 differ in two respects. Firstly the gripping members 1 2 of the nut 14 have external bosses 20 for better gripping of the surrounding wall on first insertion of the tie. Such bosses may be incorporated on the gripping members of the nut 1 3 if desired. Secondly the spreading member 16 of the nut 14 has lugs 21, best seen in Figure 2, for engaging the spreading member 1 6 with its gripping members 1 2 and hence preventing rotation of the member 1 6 when on tightening the members 1 2 grip the surrounding wall.The spreading member 1 5 of the nut 1 3 does not have such lugs since turning of the spreading member 1 5 with respect to its gripping members 1 2 is required for tightening of the nut 1 3.

The tie is provided with a shrink-fit plastics material sleeve 22 for water proofing.

For fitting of the tie, aligned bores 23,24 are made at mortar joints 25 in the inner and outer skins 2,3 of the wall. The bores are made from the outside and the bore 23 in the inner skin is blind so as not to mar the decorated inner surface of the inner skin. The length of the tie is best chosen such that the separation of the abutments 8,9 corresponds to the cavity separation of the skins 2,3. The lengths of the expanding nuts are best chosen so that they extend from the cavity to the middle of the skins.

On insertion of the tie into the bores a tubular, double-ended tool 28 with a slot at one end is engaged with the flats 7 within the outer skin to expand the nut 14 by turning the pin 4 to draw the spreading member 1 6 towards the abutment 9. Once the nut 14 is secured in the inner skin, which can be ascertained by the pin 4 being turnable no further, the tool 28 is reversed and spigots on its other end engaged in a slot 29, such as a screw head slot, in the spreading member 1 5.

It is screwed in on the now fast pin 4 to spread the nut 1 3. Securement of this nut can be ascertained by the spreading member 1 5 being turnable no further.

On withdrawal of the tool, the open end of the bore 23 is filled with mortar.

Claims

1. A tie comprising a rod having spaced abutments between its ends, having screwthreaded portions at both ends, and having means at one end by which it may be rotated about its central longitudinal axis, one radially spreadable gripping device including a nut upon the screw-threaded portion at one end, means on the nut of the one device by which it may be rotated relative to the rod, the one device being expansible by relative rotation of the one nut and rod with the one device against one abutment on the rod, and another radially spreadable gripping device including a nut upon the screwthreaded portion at the other end, the other device being expansible by relative rotation of the other nut and rod with the other device against the other abutment on the rod, the arrangement being such as to allow independent expansion of the gripping devices.

2. A tie according to claim 1, in which the other spreadable gripping device comprises a gripping member or members on the other nut.

3. A tie according to claim 2, in which the gripping member or members and the nut of the other device have interengaging formations preventing relative rotation and permitting relative longitudinal movement.

4. A tie according to any preceding claim, in which the one spreadable gripping device comprises a gripping member or members on the one nut.

5. A tie according to claim 4, in which the one nut is rotatable relative to the gripping member or members of the one device.

6. A tie according to any one of claims 2 to 5, in which the nut and gripping member or members of the one and/or other device have complementary frusto-conical contact surfaces.

7. A tie according to any preceding claim, in which the gripping device has external bore engaging bosses.

8. A tie according to any preceding claim, in which the gripping devices are encased in shrink-on tube means of plastics material.

9. A tie according-to claim 2 or 5, or any claim appendant to claim 2 or 5, in which the one and/or the other device has a plurality of gripping members held together by a spring ring fitted in external grooves therein.

10. A tie substantially as hereinbefore particularly described and illustrated in the accompanying drawings.

11. A method of tying together two spaced structural members with a tie according to any preceding claim, including the steps of: boring through a first of the two structural members and into the second structural member, the bases being aligned; inserting the tie into the bores so that the one device is in the bore in the first structural member and the other device is in the bore of the second structural member; rotating the rod of the tie to expand the other device to secure the rod in the bore in the second structural member; and thereafter, rotating the nut of the one device on the rod to expand the one device to secure the rod in the bore in the first structural member.

1 2. A method according to claim 11, including disposing the abutments on the rod at a spacing corresponding to the space between the structural members.

1 3. A method of tying together two spaced structural members with a tie, substantially as hereinbefore described with reference to the accompanying drawings.