Timber brandering or purlins in roofing structures span timber trusses as generally horizontal beams for supporting roofing sheets, tiles or ceiling boards. Typically, the brandering is connected end-to-end at joints which have to be relatively strong because these members tend to carry reasonably high loads. Conventional brandering for roofing sheets or tiles is cut so that the joints between adjacent lengths of brandering are located directly above rafters in the timber trusses, and the ends of the brandering are connected to the rafters with nails.

A problem associated with this type of joint is that the nails used to connect the lengths of timber brandering to the rafters are driven through the timber adjacent the ends of the brandering and this often causes the timber at these ends to split, thereby reducing the strength of the joint. In addition, since the joints have to be located directly above the rafters, generally it is necessary to cut the brandering whilst balancing on a partially completed roofing structure. Apart from being time consuming, this tends to be relatively dangerous and has led to accidents in the past. It will also be appreciated that cutting the brandering to the correct length on the roofing structure results in timber waste which increases the cost of the structure.

It is an object of the present invention to provide a connector for connecting two lengths of timber brandering end-to-end in a joint which is relatively strong and which is relatively easy and safe to construct.

SUMMARY OF THE INVENTION According to the invention there is provided a connector for connecting two lengths of timber brandering end-to-end comprising an elongate, hollow sleeve which is sized and shaped to receive a length of timber brandering of generally square cross section at each longitudinal end thereof and which includes at least one inwardly directed gripping formation for gripping brandering of various different cross-sectional dimensions within a predetermined tolerance by engaging or deforming the brandering.

In a preferred embodiment of the invention, the sleeve includes at least one inwardly directed stop formation located approximately midway along the length of the sleeve for limiting the extent to which brandering may be inserted into the sleeve from each longitudinal end thereof.

The stop formation may comprise a flap which extends inwardly from one side wall of the sleeve.

Typically, the flap is formed by cutting and bending a portion of one side wall of the sleeve so that one end of the flap is joined to the sleeve along a joint which extends transversely to the length of the sleeve.

In a particularly preferred embodiment, the sleeve has a generally square cross section and includes an inwardly directed gripping formation on each of two contiguous side walls thereof.

The inwardly directed grippers may comprise dimples which are stamped into the two side walls of the sleeve.

In one arrangement, the or each inwardly directed gripper comprises an elongate rib which extends from a location spaced inwardly from one end of the sleeve to a location spaced inwardly from the other end of the sleeve. In this way, the entrance to each end of the sleeve is free of grippers to facilitate the insertion of the timber brandering into the sleeve ends.

Alternatively, the grippers may comprise barbs which are directed so as to allow insertion of the brandering into the sleeve and to resist withdrawal of the brandering from the sleeve.

The sleeve may also define one or more windows in a side wall thereof for checking that the timber brandering has been properly inserted into the sleeve.

Typically, the sleeve includes one or more apertures for allowing the brandering to be locked in position within the sleeve with locking pins or the like.

The sleeve may be formed from metal sheeting, preferably a single sheet of galvanised iron which is folded along one side of the sleeve to form a seam.

Alternatively, the sleeve may be formed from two sheets of galvanised iron which are connected together along two of the corner edges of the sleeve.

Although the thickness of the metal sheet will depend upon the particular application of the connector, in one application the sleeve is formed from galvanised iron sheeting having a thickness of approximately 0.5 mm.

The sleeve may also be formed from other materials such as a plastics material. The invention extends to a timber joint comprising a sleeve as described above and two lengths of timber joined end-to-end by insertion into opposite ends of the sleeve.

The joined timber may be used in roofing applications, ceiling applications or other structural applications.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a perspective view of a connector according to the present invention with two lengths of brandering adjacent the connector; Figure 2 shows a cross-sectional view along the line 2-2 in Figure 1; Figure 3 shows a cross-sectional view similar to that of Figure 2 with brandering of a first cross-sectional dimension inserted into the connector; and Figure 4 shows a cross-sectional view similar to that of Figure 2 with brandering of a second cross-sectional dimension inserted into the connector.

DESCRIPTION OF A PREFERRED EMBODIMENT Figure 1 of the accompanying drawings illustrates a connector 10 according to the present invention. As can be seen, the connector 10 comprises a sleeve 12 which defines a hollow passage 14 therethrough. In this embodiment of the invention, the sleeve 12 has a generally square cross- sectional shape and is preferably formed from sheet metal, for example 0.5 mm thick galvanised iron, which is both reasonably strong and corrosion resistant.

With reference also to Figure 2 of the drawings, two contiguous side walls 16 and 18 of the sleeve 12 include inwardly directed gripping formations in the form of two ribs 20 and 22. In the illustrated embodiment, the ribs 20 and 22 are stamped from the side walls 16 and 18 and extend from locations 24 and 26 spaced inwardly from one end 28 of the sleeve 12 to locations spaced inwardly from the opposite end 30 of the sleeve.

In a central region 32 of the sleeve, a stop formation in the form of a generally square web or flap 34 limits the extent to which brandering 36 and 38 can be inserted into the sleeve 12 from either of the ends 28 and 30 thereof. The flap 34 is cut from a side wall 40 of the sleeve and is bent at 90° to the length of the sleeve, as shown. The opening formed by bending the flap 34 into the sleeve 12 creates a window 42 for checking that the brandering has been properly inserted into the sleeve. It will be appreciated that the window 42 allows for checking on only one side of the flap 34, and accordingly another, similar window (not shown) may be provided adjacent the flap 34 for checking the brandering on the other side of this flap.

In Figure 1 of the drawings, the side wall 40 is seen to include two apertures 44 for locking brandering within the sleeve 12 with locking pins or nails 45.

The sleeve 12 in the illustrated embodiment is formed from a single piece of galvanised iron which is joined along a seam 46 on a side wall 48 of the sleeve. However, the sleeve 12 could also be formed from two pieces of galvanised iron which are joined together along corner edges of the sleeve, if desired.

The cross-sectional dimensions and the length of the sleeve 12 are selected to accommodate the dimensions of the timber brandering to be joined together. For example, 38x38 timber brandering generally has cross- sectional dimensions of 38mm by 38mm with a tolerance of say-2mm. In this case, the internal passage 14 of the sleeve 12 will be dimensioned so that the entrances to this passage can receive 38mm by 38mm brandering with a sliding fit, and the ribs 20 and 22 will be dimensioned so as to extend a little more than 2mm into the passage 14, thereby to engage brandering with cross-sectional dimensions of 36mm by 36mm.

In practice, the two lengths of brandering 36 and 38 are connected together by simply inserting one of the lengths of brandering 36 into the end 28 of the sleeve 12 and feeding the brandering 36 along the hollow passage 14 until the end 50 thereof buts against the flap 34, and then inserting the other length of brandering 38 into the end 30 of the sleeve 12 and feeding this brandering along the passage 14 until it buts against the flap 34. As the brandering 36 and 38 is fed along the passage 14 it engages the ribs 20 and 22. Where the cross-sectional dimensions of the brandering are 36mm by 36mm, the brandering is engaged by the gripping ribs 20 and 22 and held in position in the manner illustrated in Figure 3. Where the brandering cross-sectional dimensions are greater than 36mm by 36mm, the ribs 20 and 22 deform the outer surfaces of the brandering as it is forced along the passage 14 to grip the brandering in position in the manner illustrated in Figure 4. It will be appreciated that the absence of gripping formations at the entrances to the passage 14 facilitates the insertion of the brandering 36 and 38 into the sleeve 12.

The stop formation 34 and the inwardly directed gripping formations 20 and 22 need not take the form of that shown in the drawings, although it is considered important that the sleeve is not easily removable from the timber brandering and that one length of brandering cannot be inserted into the sleeve beyond the approximate midpoint thereof.

One advantage of the connector of the present invention is that, provided the sleeve 12 is formed from a material which is reasonably strong, the joint between two lengths of brandering should be at least as strong as the timber brandering itself. This is a significant improvement over conventional connections between timber brandering where, generally, the joint is considered to be a weak point.

A further advantage of the connector according to the present invention is that it is not necessary to cut the brandering before effecting the joint, as is the case with conventional brandering joints. This is advantageous because it tends to be difficult, dangerous and time consuming to cut brandering while balancing on a roofing structure.

It is envisaged that prior to even lifting the brandering onto the roof, sleeves 12 will be fitted to one of the ends of some brandering, and thereafter the brandering will be lifted onto the roof and nailed into position with the sleeves already fitted. The brandering to be joined end-to-end with that already in position will simply be slotted into the opposite ends of the sleeves 12 and nailed into position. In this way, the joints can be effected relatively quickly and easily by non-skilled labour.

Apart from being stronger than conventional joints, the joints constructed with connectors according to the invention will result in very little timber loss from off-cuts.