The present invention relates to fence posts and in particular but not solely related to fence posts made of recycled plastic materials. BACKGROUND

Fence posts of traditional design are manufactured from wood. When located in the ground they will rot if the post is not treated. Even if the wood is treated, over a long period of time it may still rot. The post also will leach into the ground the toxic materials which are used to treat the post. For many applications this is acceptable. However there are applications, where this is unacceptable or undesirable such as for example organic farming or where a high quality of grape is desired from a vine. Thus the presence of such contaminants in the ground is not desirable.

Furthermore the removal and placement of a wooden post is time consuming in comparison to its insertion into the ground. Often the post must be dug out completely around its periphery and depth to remove it and any decomposed parts which remain within the ground. This is particularly the case when the post has commenced rotting.

Concrete posts have also been known in the art. However these are heavy for their relative strength and fragile also. Further, they can be expensive. Additionally they do not readily behave like a normal wooded fence post, for example the convenience of nailing.

The use of plastic to manufacture fence posts and fencing systems is known, for example in NZ214153 and NZ 239872 of Quinn et al. These patents disclose a plastic post which requires an insert to retain the wires thereon.

Furthermore NZ246034 (Instant Foundations) discloses a ground anchor of plastic construction with an external thread and flange for ground insertion and load bearing.

Therefore to have a post which has a long lifetime, does not rot or contaminate the ground has ease of use of insertion, and also of removal if

desired, is of benefit. The useful repository for recycled materials also has a benefit. BRIEF DESCRIPTION OF THE INVENTION

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

It is therefore an objective of the present invention to provide a fencing post which at least goes someway to addressing the above shortcomings of the prior art or which will at least provide the public with a useful choice.

In a first aspect the present invention may be said to broadly consist in a fence post for engagement with the ground via insertion therein, wherein at least that part of said fence post which is to be inserted into said ground is tubular wherein the internal surface of the tube includes an internal thread extending between a ground engaging end and end of said fence post distance from the ground engaging end. In a second aspect the present invention may be said to broadly consist in a fence post for engagement with the ground via insertion therein, said fence post comprising or including, a hollow tubular member having a longitudinal axis, the hollow tubular member including an internal thread about said longitudinal axis extending to a ground penetrating end of said hollow tubular member.

Preferably at said ground penetrating end there is an internally angled peripheral chamfer to aid cutting of said ground upon insertion.

Preferably said fence post is made of plastic.

Preferably said plastic is recycled plastic.

Preferably said internal thread is of a coarse pitch of approximately at least the internal diameter of said hollow tubular member of said fence post.

Preferably said angled peripheral chamfer acts as a cutting edge, to aid engagement and insertion with and into said ground. Preferably said peripheral chamfer may be notched or toothed to further aid cutting and engagement of said ground.

Preferably said plastic is of a type which can be cut or penetratively fastened thereto for attachment of members, e.g. wire, bracing and the like.

Preferably said internal thread and peripheral chamfer aid insertion of said fence post into said ground when rotation about said longitudinal axis and pressure parallel to said longitudinal axis and toward said ground are applied to said post.

Preferably said fence post has, distal from its ground penetrative end, engagement means for engagement with insertion apparatus. Preferably said engagement means is complimentary to said insertion apparatus such that said insertion apparatus can impart both said rotation and pressure.

Preferably said engagement means is an aperture through said fence post perpendicular to the longitudinal axis of said fence post. Preferably said aperture is a through hole or blind hole.

Preferably said post is of entirely circular tubular cross section. Preferably said tubular member is able to engage an extension member to allow the height of said fence to be increased when greater fence height is required (e.g. for deer fencing or a wind break). Preferably said distal end of said tubular member is hollow to receive an extension to be retained in place by a pin there through.

Preferably there is an attachment member intermediate of said distal end and said extension.

Preferably said attachment member attaches to said fence post by sleeved engagement.

Preferably said attachment member attaches to said extension by sleeved engagement.

Preferably said attachment member is sleeved inside said fence post distal end. Preferably said attachment member is sleeved inside said extension.

Preferably said attachment member is retained to both said fence post and said extension via two or more pins.

In a further aspect the present invention consists in a method of fence post insertion to insert a proximal end thereof into a retaining medium (e.g. the ground or earth) comprising or including the steps of, engaging said fence post with a driving means at a location distal from said proximal end, said driving means capable of applying rotation about the longitudinal axis of said fence post and pressure parallel to said longitudinal axis toward said retaining medium, said fence post is of a hollow and tubular elongate cross-section at least in that part to be engaged with said medium, said post further having an internal threaded portion towards said proximal end of said hollow and tubular portion, said post being driven into said medium by said driving means, with said rotation being in the engaging direction of a said thread, which together with said internal thread can provide an in medium retained fence post.

Preferably said driving means is powered.

Preferably said powered driving means engages with the distal end of said fence post. Preferably said powered driving means engages with said fence post via a complimentary engagement means.

Preferably said complimentary engagement means engages with at least one surface substantially perpendicular to said longitudinal axis to transmit said pressure.

Preferably said complimentary engagement means engages with at least one surface substantially parallel to said longitudinal axis to transmit said rotation.

Preferably said complimentary engagement means is a socket attachment.

Preferably said socket attachment engages with said distal end via a pin therethrough to at least transmit said rotation to said post.

Preferably said pin transfers said pressure to said fence post also.

Preferably said pin therethrough is perpendicular to said longitudinal axis.

Preferably said socket attachment also engages a surface ("the top surface") at said distal end to impart said pressure parallel to said longitudinal axis.

Preferably rotation of said fence post in the opposite direction aids to the remove said fence post from the ground.

In a further aspect still the present invention consists in a method of fence erection wherein at least one fence post as claimed in any one of claims 2 to 23 is driven into the ground and thereafter fencing material is run between said posts to form a fence line. Preferably said fencing material is at least one wire.

Preferably said fencing material is retained to said post by nailing.

Preferably said fencing material is retained to said at least one fence post by cuts in the periphery of said fence post only.

Preferably said cuts are made at least in part by thermal energy. Preferably the distal end of said at least one fence post to is able to engage an extension to said fence post to allow the height of said fence to be increased when greater fence height is required (e.g. for deer fencing or a wind break).

Preferably said distal end is hollow to receive said extension, either directly or by sleeved engagement of an intermediate attachment member and is retained in place by a pin there through.

Preferably rotation of said at least one fence post opposite to that rotation applied upon insertion thereof aids in removal of said fence post from the ground.

In yet another aspect the present invention consists in a fence post as herein described with reference to any one or more of the accompanying drawings. In yet a further aspect the present invention consists in a method of fence manufacture as herein described with reference to any one or more of the accompanying drawings.

In yet a further aspect still the present invention consists in apparatus form a method of fence manufacture as herein described with reference to any one or more of the accompanying drawings.

In yet another further aspect the present invention consists in fence as herein described with reference to any one or more of the accompanying drawings.

In yet another further aspect still the present invention consists in fence manufactured by the method as herein described with reference to any one or more of the accompanying drawings.

The term 'comprising' as used in this specification means 'consisting at least in part of, that is to say when interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such

known equivalents are deemed to be incorporated herein as if individually set forth.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings in which, BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows an isometric upright view of a fence post of the present invention,

Figure 2 shows a vertical cross section through the fence post of figure 1, with Figure IA showing a fence post of hollow construction, Figure 2B showing a fence post of partial hollow construction, and Figure 2C showing a fence post of hollow construction with an internal thread along the entire length,

Figure 3 shows the fence post of the present invention with attached driving apparatus for insertion into the ground (and/or removal from the ground also), Figure 4 shows a fence post in situ in the ground with wire attached to form a fence,

Figure 5 shows in side elevation a similar view to that of Figure 4 with the addition of an extension to the fence to give increased height, e.g. for deer fencing or to hold a wind break, and Figure 6b shows a further method of attaching the extension, by use of the attachment member of Figure 6a.

Preferred embodiments of the present invention will now be described with reference to Figures 1 through 6. BRIEF DESCRIPTION OF THE INVENTION In a preferred embodiment the fence post (1) is of substantially hollow cross section; the hollow (7) extending all the way through the length of the fence post (1). In another embodiment the hollow (7) may only partially extend from the ground engaging end (5), preferably at least however to a depth into the post at least equal to the depth of engagement in the ground 3. This will allow sufficient space for the earth of the ground to move up the hollow, and will prevent

compaction and binding of the fence post. Around the periphery of the hollow (7) at the ground engaging end (5) there is an internally angled peripheral chamfer (11). This peripheral chamfer (11) produces an edge which aids cutting of the ground (3) to aid the installation of the fence post (1). Additionally optionally the ground engaging end (5) may have teeth or notches (40) to help cut the ground and/or roots or similar that may be present, again to aid installation of the fence post.

Towards the ground engaging end (5) in the hollow (7) there is an internal thread (9). In preferred embodiments the thread is of pitch P which is greater than or equal to the internal diameter D of the hollow (7). However any pitch may generally be used. The internal thread (9) may extend the full length of the hollow (7) as in Figure 2 C or, may only extend part of the way as in Figure 2B, or any variation in between. Multi-start threads are also considered within the scope of the invention. The purpose of the thread (9) is twofold; first of all the thread aids insertion into the ground. The pressure downwards into the ground and rotation in a direction to engage the thread (the direction of the thread) are applied to the post the thread will aid in the thread like engagement with the ground as the post is inserted into the ground. Secondly the thread provides a keying with the ground to resist pulling out fences and also spreads the area for lateral loads applied. Thirdly the thread will provide the benefit that when the post is to be removed the application of an upwards force together with the opposite rotation will essentially unthread the post from the ground thus freeing it and enabling the removal of the post to be effected with greater ease. The method of insertion of the fence post (1) into the ground (3) is achieved as follows.

The post (1) has attached towards the end distal from insertion (29) a socket attachment (31) which fits at least in part over the end (29). The socket may be retained in a number of ways however the preferred method is by use of a pin (14) which passes through the socket attachment (31) and the post (1) to provide

at least a rotational engagement of the two. The socket (31) may also bear upon any planar surface (33) for example the top surface of the post (1) to apply a force downwards into the ground. The post (1) is rotated in the engaging direction to allow the tread (9) to "screw" into the ground. The combination of rotation and force downwards therefore propels the ground engaging end (5) into the ground (3). At the ground engaging end (5) there is the internally angled peripheral chamfer (11) and optionally notch or tooth (40). This produces a cutting edge on the first part of the fence post (1) to contact the ground (3). This peripheral chamfer may also optionally be toothed or notched to further engage the ground and aid in breaking up of the ground to ease the penetration of the fence post.

The socket attachment (31) is driven from a powered driving means (27) which may be the power take-off of a tractor or other farm implement. Provided there is at least a surface present to take the pressure (42) and at least one surface to take the rotation (43) then the engagement with the socket will be achieved. For example the top end of the fence post (1) may be of hexagonal shape (or any other polygonal form) which presents surfaces for imparting rotation and the upper end surface of the fence post (1) may take the pressure (42) force.

The fence post (1) once engaged into the ground can have wires (4) whether of barbed or normal or other configurations attached to its outer periphery. The wires may be attached by either the standard method of using penetrative fastenings (22) e.g. a U or horse-shoe nail. Alternatively the wire (4) may be engaged into the outer periphery by the provision of a cut (21) in the outer periphery. Such cut may be produced by means known in the art for creating such incisions; other means also due to the plastic nature of material may be used such as thermal or heat generating tools (e.g. a heated wire) to produce such a cut. Of course a combination of cut and penetrative fastenings may also be used. The fence post (1) maybe easily removed by reversing the rotation direction and upwards force.

The use of the fence post together with wire and other fence posts whether of the current invention or otherwise will be able to produce a fence line for the controlling of stock units defining or controlling access to an area.

An extension is optionally able to be attached to the top of the fence post. The attachment method may take many forms.

One set of methods is the sleeving of the extension (8) with the distal end (29). This may take the form of the extension sleeving into the fence post or vice versa. The sleeving in one form, utilises a distal end hollow (12) at the end distal to the ground (that is the top of the fence post). This hollow (12) allows for the attachment by insertion of an extension (8). The extension (8) may be held in place utilising the apertures (26) and an extension pin (16). Alternatively other apertures may be provided. In a preferred embodiment shown in Figure 6, an attachment member (34) has at least one protrusion (35) projecting therefrom to engage with the hollow (12) of the fence post (1). The inclusion of the pin (16) locks the attachment member (34). The attachment member may have a second protrusion (36) which can engage in a like complementary hollow (37). There after a further pin (16) locks the extension (8), attachment member (34) and fence post (1) together.

In other embodiments the extension may have a hollow to receive the fence post (1) and be retained thereto by a pin.

In one preferred embodiment an attachment member (34) sleeves into both the fence post (1) and the extension (8), in the embodiment shown the attachment member (34) fits within a distal end hollow (12) and sleeves in a similar way into the extension (8). Alternatively the attachment member (34) may sleeve on the outside of either or both of the fence post and extension.

The extension may have normal wires (4) (e.g. for deer fencing) or may have netting (38) or similar (4) for creating a shelter belt or otherwise. Such removable extensions allow for the height of the fence system to be easily adjusted as per the use requirements of the area in which the fence is deployed.

Further extensions may be added to the in place extension to extend the height of the fence as need be. If the fence post (1) is sufficiently braced then no added bracing is needed. However should more stability be required (e.g. for high fencing, and or wind protection) then added bracing (39) may be added. A brace post (6) may also be utilised where the fence post (1) is to take large amounts of strain (e.g. at corners or in long runs of fencing). The brace post (6) may be a traditional wood based design or maybe of the preferred embodiment plastic fence post (1) of the present invention driven into the ground by means as described. The brace post (6) may notch into the plastic in a preformed aperture in the post as per traditional means or maybe pinned in place additionally.

The forgoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention as defined by the accompanying claims.