This invention relates to a fastening system and more particularly to a clip fastener for use with posts. -The invention will be described in relation to its application to fence posts and fencing systems but is not limited to such applications. For example, the invention may be used in fastening signs or reflector plates to posts or for supporting irrigation piping. BACKGROUND ART

Fencing wires in the past have been attached to wooden posts by means of staples. Wooden posts have recently been replaced by steel posts. These posts usually have a longitudinal gripping means running the length thereof. An exemplary form of such a post has a substantially closed channel portion and two flanges projecting outwardly one with respect to the other from respective edges of said channel portion to define two respective lips extending substantially along the length of said post and bent backwards to present the wire cutting on the edges.

Fencing wires are normally attached to these previously known steel posts by means of staple which is driven or hammered into the post groove. This has the disadvantage of usually requiring a special tool, such as compressed air staple gun, to drive the staple into the groove. Use of manual means, such as a hammer, results in problems of holding the post rigid and the resilience of the post groove lips.

A further problem with known systems is that insertion of the staple results in expansion or spreading of the groove lips at and adjacent to the point of insertion. This expansion makes the insertion of staples adjacent to each other extremely difficult as the retention force applied by the groove lips to the staples is reduced and can result in loose staples and poor retention of fencing wires. It has been found that staples must be spaced by at least 10 cm in order maintain reasonable retention by the groove lips.

A further disadvantage is that with time and movement of the fence wires the staples become loose and may slide within the groove or come loose altogether. DISCLOSURE OF INVENTION

An object of the present invention is to provide a clip fastener which overcomes at least some of these dis¬ advantages and provides a simple clip which is inexpensive to manufacture and can be installed by thumb pressure or with a hand tool using only hand pressure.

According to a first aspect, the present invention consists in a clip fastener, for use with a post of the kind hereinbefore described, comprising: a retaining portion adapted to abut the post adjacent the post groove so as to provide a flange adapted to retain a member said retaining portion extending laterally of an anchor portion, said anchor portion adapted to be inserted into the post groove and having a resilient barb means adapted to engage the inner wall of the post groove.

The resilient barb means preferably comprises a tongue cut from the anchor portion to form a prong or detente extending at angle thereto. The end of the prong is preferably crescent shaped to produce two sharp edge points which engage with the inner wall of the post groove.

According to a second aspect, the invention comprises in combination: a post comprising a substantially closed channel portion and two flanges projecting outwardly one with respect to the other from respective edges of said channel portion to define two respective lips extending substantially along the length of said post, and a fastener comprising, a retaining portion abutting said flanges adjacent said channel portion and forming a flange adapted to retain a member,

and an anchor portion extending laterally of said wire retaining portion and inserted between the lips of the post having a resilient barb means engaging the inner wall of the post channel.

According to a third aspect, the invention comprises a method of constructing a fence including the steps of: clamping a fencing wire or mesh to a fence post having a longitudinally extending grooved hollow by means of the clip fastener according to the first aspect. BRIEF DESCRIPTION OF DRAWINGS

A preferred embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a side elevation of the clip fastener according to the invention;

Figure 2 is an end elevation of the clip fastener shown in Figure 1;

Figure 3 is a side elevation of a clip fastener according to a further embodiment of the invention?

Figure 4 is a plan view of a fence post with the clip fastener according to the invention in place;

Figure 5 is a front view of the fence post showing the clip fastener with fence wire attached.

Figure 6 is a perspective view of the clip fastener according to the invention showing an angled retention means;

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, the clip fastener is preferably manufactured in one piece from sheet spring steel of approximately 1-1.5mm thickness, however other resilient materials such as plastic could be used. The clip has an anchor portion 1 and a retaining portion 2 extending laterally thereto as shown in Figures 1 and 2. A'-,resilient barb is formed by cutting and pressing out a tongue of material to form a prong 3. This prong preferably has a crescent-shaped free end 5.

The retaining portion 2 has a semi-circular deformation 4 to enable the retention of the fence wire or the like.

Figure 3 shows a dual anchorage type arrangement wherein the retaining deformation 4 links the two anchor portions 1.

In use, as shown in figures 4 and 5, the anchor portion 1 is aligned with the groove of the fence post formed by lips 8 of the closed channel fence post 6. The anchor portion is then pressed using only thumb pressure into the groove. Barb 3 is resiliently deformed as the anchor portion enters the groove being compressed by the lips 8 of the post groove. Barb 3 is arranged to be biased outwardly to engage with the inner wall 9 of the post. The fastener is held in clip engagement between the barb 3 engaging the interior wall 9 and the retaining portion 2 abutting the outwardly extending flanges 7 of

the post. The dimensions of the clip fastener are arranged such that the clip is firmly held by the resilient force applied by the barb 3. Further, the barb 3 will oppose any force applied to remove the clip fastener from the groove.

In order to improve resistance to movement along the length σf the groove by the clip fastener the barb preferably has a crescent-shaped free end 5 to form points which engage with, and may even deform the inner surface 9 of the groove. These points greatly increase the resistance of the fastener, once inserted, to translation longitudinally along the post groove.

Further resistance to movement of the fastener may be provided by forming two inwardly extending barbs at the junction of the anchor portion and the retaining portion. These barbs are arranged to engage with the surface of the post on insertion of the clip and resist movement of the clip relative to the post. Barbs can also be formed on the flat surfaces of the clip by burst punching holes therein to produce a ragged edged hole. These edges again engage with the surface of the post to resist movement of the clip.

Resistance to movement by the clip along the length of the post groove may be further increased by roughening of the inner surface 9 of the groove. This is done by providing a plurality of deformations along this surface for interengagement with the barb 3 of the clip. These

deformations are preferably provided by rolling the post member, before it is formed into its specific cross-sectional shape, with spiked rollers which score or deform the surface of the post member. This rolling is confined to an area of the post member which will form the inner surface of the post once it is formed into its cross-sectional shape.

Figure 5 shows the clip being used to retain barbed wire 10, however the clip is not limited to use with fencing wire and may be used with any form of elongated member. Other possible uses would include mounting of conductive wires for use with electric fences and having insulators which would be retained by the clip.

Figure 6 is a perspective view of a clip" fastener with an angled wire retention means. Such a fastener is used for cross mesh or diamond mesh fences. The size and thickness of the fasteners can be varied according to their required purpose.

The clip fastener is preferably manufactured by a single stamping and pressing from a sheet of resilient material.

Whilst the embodiments of the present invention have been described with reference to a post have a particular cross-sectional shape it will be apparent to those skilled in the art that the clip fastener of the present invention may be used in conjunction with fence posts having different cross-sectional shapes. It will also be

apparent that other embodiments of the invention described are possible without departing from the spirit or scope of the invention.