TITLE OF THE INVENTION

IMPROVEMENTS IN AND RELATING TO FENCING AND MARKER PEGS BACKGROUND TO THE INVENTION

This invention relates to an attachment for fencing posts and marker poles and construction means and methods for setting fence posts and marker poles in combination with the attachment of the invention in the ground and removing same when required.

Fibre-reinforced plastics materials are commonly used in the construction of fence posts, temporary electric fence pegs and other post and pole-like devices such as markers for sports activities. In the following discussion much reference will be made to glass reinforced fence posts. These references are intended to apply equally to other types of plastic elongate structural members which are mounted on or in a substrate of some sort, including those constructed from non- reinforced materials that share broadly similar structural engineering properties to the reinforced materials (such as semi-rigid PVC).

Reinforced plastic materials typically have good durability, stiffness, elasticity, creep resistance and insulating properties which make them ideal for electric fencing, in particular. These fibre-reinforced plastics materials can be used in a variety of manufacturing methods such as injection moulding, hand laying, extrusion and pultrusion, although pultrusion (the final product is winched through dies rather than pushed with pressure as in extrusion) achieves the most cost-effective result for commodity products such as fence posts. Fence posts are usually constructed from uniform round section pultruded rod in diameters of between 8mm and 25mm and in a large range of lengths to suit different fence specifications.

Despite the many excellent properties of glass-reinforced pultruded plastic posts there are some significant deficiencies with the simple straight rod-like version that is commonly used:

Firstly, in a typical fence line, fence posts on brow points will be under compression from the tensioned fence wires and fence posts in depressions will be tending to lift from the ground because of the forces generated by wire tension. The smooth surface and small diameter of the simple pultruded posts offers little resistance to sinking into the ground or pulling from it.

Secondly, from an engineering perspective, the constant diameter of the pultruded fence post represents an inefficient use of material in the sense that the bending and compressive forces that the posts are frequently subjected to increase with proximity to the ground because of simple leverage effects and from the cumulative load imposed by multi-wired fences. It would thus be more efficient to progressively increase the cross section of the post closer to ground level. On the other hand, a constant diameter post is convenient from the perspective of the need to provide simple and adjustable holding means for the horizontal elements of the fence. Although pultrusion is a very cost effective method of manufacture for fibre-reinforced elongate structural members, it does not permit the direct production of tapered profiles.

Thirdly, despite the remarkable flexibility of some fibre-reinforced plastic rod, this material is significantly notch sensitive and if stresses are concentrated by some form of stress raiser it is likely to fail under relatively modest bending loads. This situation commonly occurs in practice where posts are planted in very hard, rocky or frozen ground.

Fourthly, the small diameter of common sizes of glass reinforced plastic posts is such that the post will tend to cut through softer soil types when exposed to strong and/or frequent horizontal forces thus opening up a clearance around the post (creating a "bell-mouth")

which diminishes the grip of the post in the soil and reduces its effective stiffness, since horizontal loadings on the fence now exercise increased leverage about the lower point where the post is effectively anchored in the ground.

SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide an attachment for glass reinforced fence posts which improves grip in the ground, increases the stiffness of the post, reduces its sensitivity to stress raisers and reduces the tendency for clearance to open up between the post and the ground near the point of entry.

A further object of this invention is to provide an efficient and time effective means and method of setting said fence posts and attachments in the ground and removing them when required.

Broadly in one aspect the present invention provides an attachment for fitment to an end of an elongate flexible plastic or glass-reinforced plastic member such as a fence post, fence pole, marker, flag pole or the like (herein "pole") the attachment comprising a sleeve in which one end of the pole can be fixed to reinforce said one end of the pole, the sleeve being made at least partially from a resilient plastics material to provide a flexural support to the pole at that part of the pole which, in use, will be at the point of entry of the pole into the ground, said flexural support providing a stress spreading function.

BRIEF DESCRIPTION OF THE INVENTION

Figure 1 is a perspective view of a first embodiment of the attachment according to the present invention in combination with a post/pole,

Figure 2 is the combination of Figure 1 when installed in the ground,

Figure 3 is an elevation view of the combination, Figure 1 ,

Figure 4 is a side elevation view of the arrangement in Figure 3,

Figure 5 is a bottom plan view of the arrangement in Figures 3 and 4,

Figure 6 is an illustration of the combination of attachment and post/pole being inserted into the ground and withdrawn therefrom.

Figure 7 is an elevation view of a second embodiment of the attachment in combination with a post/pole,

Figure 8 is an exploded view of the combination shown in Figure 7,

Figure 9 is an enlarged view (detail A) of the sleeve component of the attachment of Figures 7 and 8,

Figure 10 is detail B of Figure 7,

Figure 1 1 is a sequence of illustrations showing the attachment with post/pole being inserted into the ground,

Figure 12 is an elevation view of the attachment with post/pole in the as installed in the ground or configuration and showing one method of anchorage,

Figure 13 is detail C of Figure 12,

Figure 14 is a view similar to Figure 1 2 but showing a second method of anchorage,

Figure 1 5 is detail D of Figure 14,

Figure 1 6 is a perspective illustration of a third embodiment of the attachment,

Figure 1 7 is a further perspective view of the third embodiment of Figure 20, - ^~

Figure 1 8 is a perspective view of a plurality of the attachments of Figures 16 and 1 7 coupled together for storage/transportation purposes,

Figure 1 9 is a cross-sectional view of the arrangement shown in Figure 1 8,

Figure 20 is a perspective view of a rammer/extractor tool for installing in and removing from the ground of attachment and post/pole combinations,

Figure 21 is a further perspective view of the tool of Figure 20,

Figure 22 is an illustration of the tool and post/pole with attachment in the configuration when the tool is used to ram the post/pole into the ground,

Figure 23 is an illustration of the tool and a post/pole with attachment with the tool in a configuration used to lift the post/pole from the ground,

Figure 24 is a perspective view of a pilot tool used to pre-form a pilot hole in hard or rocky ground,

Figure 25 is a perspective elevation view of the tool of Figures 16 and 1 7 in combination with the pilot tool of Figure 20, and

Figure 26 is a further perspective view of the combination of Figure 21 ,

DETAILED DESCRIPTIONS OF EMBODIMENTS OF THE INVENTIONS

In the following more detailed description of the invention in its various embodiments the attachment 10 according to the invention will be described in combination with a post or pole P. According to the most preferred form of the invention the post/pole will be a pultruded fibreglass shaft. For ease of description this component will simply be referred to as a pole P.

The attachment 10 in its simplest form is a sleeve which is attached by suitable means to the end of the pole (the lower end) which will be inserted into the ground. The sleeve provides reinforcement to the lower end of the pole. The sleeve can be simply a tubular element of constant of cross-section or could be of a more preferred construction where it tapers toward its upper end. It preferably also tapers toward its lower end.

The sleeve can be manufactured from any suitable material such as a plastics material or from metal but as hereinafter described will be in part made of a resilient plastics material to provide a flexural support to the pole at that part of the pole which, in use, will be at the point of entry of the pole into the ground. This flexural support provides a stress spreading function.

The references to "upper" and "lower" and like terms are herein to be interpreted in relation to a pole and its attachment in the orientation when inserted into the ground with the axis of the pole and attachment projecting above and below ground level.

In the following description more complex and preferred embodiments of the sleeve attachment member 10 will be described. Consequently referring to Figures 1 -5 there is shown the attachment 10 fitted to the end of a pole P. In one form of the invention the

attachment 10 is of a moulded plastics construction and preferably is actually moulded onto the lower end of a pre-formed pole P. In alternative arrangements a more mechanical attachment is achieved post moulding by inserting the end of the pole P into the attachment 10 in a positive engagement so that the pole is fixed to the attachment.

The attachment 1 0 in its preferred form has a tapered upper section 1 1 , a trunk section 12 and a lower end which is tapered and formed with wings 1 3.

The tapered section 1 1 and a part of the trunk 1 2 is provided with a bore 14 into which the lower end of the pole P can be inserted. This may be simply an interference fit though in the form of the invention as illustrated the end of the pole P has deformations such as threads or grooves 1 5 in the surface near the lower end. The deformations 1 5 preferably progressively blend out toward the upper end of the deformed or grooved area so as to avoid a pronounced stress raiser on pole P. Deformations 1 5 provide a secure means of anchoring pole P in attachment 10. When deformations 1 5 are in the form of a thread the pole P can be readily detached from the attachment 10.

The trunk section 12 is relatively stiff and is intended to lie in the region of attachment 10 where it emanates from the ground when pole P is in its normal placement in the ground or substrate. Blades or fins 1 6 formed with or attached to trunk 1 2 provide a large surface to resist movement in the soil when pole P is subjected to lateral forces. In this embodiment fins 1 6 are shown in one plane only since lateral forces tend to be more frequently applied in a direction normal to the fence-line, however, other embodiments may have fins in 2 or more planes. The third embodiment of Figures 16 and 1 7 is an example of fins in more than one plane. Thus fins can be provided in the plane of the wings 1 2 and/or at right angles (or any other suitable orientation) relative to the plane of the wings 1 3.

Above trunk 12 is the conical or substantially tapered section 1 1 which provides a gradually reducing flexural reinforcement of pole P to avoid a sudden transition which might act as a

stress raiser. In this embodiment section 1 1 is represented as a frustoconical form although many other embodiments are possible such as a plurality of tapering webs or gussets. To avoid a stress raiser at the top of section 1 1 notches 1 7 of e.g. substantially U or V shape provide a transition of flexural support in this area. Alternatively, the bore of section 1 1 could be progressively relieved to create a bell mouth at this point, or tapered down to a fine edge. This portion of the attachment will be formed from a resilient plastic material.

The wings 1 3 at or adjacent the lowermost end of the attachment provide an enlarged surface to resist lateral movement in the ground as well as a means of anchoring the attachment 10 in the ground. Wings 1 3 are preferably made from a resiliency deformable plastics material which can be actively bent (preferably at the distal end) by an operator before placement into the ground or passively bent as attachment 10 is lifted upwards in the ground.

Figure 1 shows wings 13 in various positions. For ease of manufacture and transport wings! 3 can be manufactured in a straight orientation which may also be preferred if the operator does not wish to anchor pole P too firmly in the ground. Wings 13 can be actively deformed with a variety of tools such as locking pliers or simply by pressing downwards with a foot.

Figure 2 shows the pole P with attachment 10 as it would normally be positioned in the ground.

Figure 6 represents the sequence of actions and changes in wings 1 3 during the process of setting a pole and attachment combination in the ground. The soil-air interface or "ground- zero" is represented as Z. In the left hand view wings 1 3 are shown in the unmodified configuration. The adjacent view shows the wings 1 3 after an operator has actively bent the wings to the point where the elastic limit of the material is surpassed and a measure of plastic deformation has occurred. Wing 1 3 is preferably bent more sharply at the distal end

or tip 1 3a thereof to provide a catching point when the post is eventually moved upwards in the soil or substrate. As shown wings 1 3 normally flex to some extent back into a straighter configuration when the pole is driven into the ground.

When the pole P has been driven into its fully inserted position the wings 13 are, as shown in Figure 6, in a slightly deformed configuration but because of the elastic memory they will nevertheless be biased outward toward to the configuration prior to the attachment being driven into the ground.

Figure 6 shows in the three right hand views (as represented by the upward arrow) the pole P and attachment 10 being pulled upwards in the ground. The wings 1 3 progressively splay outward as they catch in the ground or substrate. The extreme right hand view shows the wings 1 3 in a fully set configuration with the pole P at the desired height relative to the ground level Z and the trunk 12 in the desired position where it is ready to withstand the highest forces created at ground level Z.

Figure 7 shows pole P and attachment 10' in a second preferred embodiment more suited to very hard and rocky ground than the winged version of Fig 1. Figure 8 shows the components in an exploded view to provide a clearer view of individual features. Attachment 10' is comprised of two sub-components namely a tube 18 which is has a bore slightly larger than the diameter of pole P and a plastic or elastomeric component 19 which partially and co-axially embeds metal tube 18 during manufacture, as shown in Fig 7. Figure 7 shows the components in an as-purchased configuration with pole P inserted in attachment 10' and aris R above tab 21 ready to be driven or pressed against tab 21 .

Component 19 is provided with the features of conical section 1 T, notch 1 7' and trunk 12' that largely fulfil the same functions as the corresponding features of the first embodiment. In this configuration, blades 16 are shown in three planes. At the lowest point of blades 16', feet 22 extend below trunk 12' to provide a footing on a hard and uneven surface. Feet 22

are of a size, material and shape such that they can either be cut or crushed to conform to the contour of a hard surface.

Tube 1 8 is preferably made from a strong durable metal such as stainless steel. It is provided with holes, threads, deformations or tabs 22 to provide secure anchorage in plastic part 19 in which it is preferably moulded as an insert. Optionally, tube 1 8 could be threaded or pressed into component 1 9. Tabs 21 are lanced from the wall of tube 18 and are formed in a manner which enables them to be folded outwards from the bore 23 of tube 1 8 under pressure from the raised or pointed end R of pole P.

In this embodiment the tabs 21 are shown to be hinged at their lower end (see e.g. Figure 1 5), but they could alternatively be hinged at their upper end. Figures 9 and 10 show magnified detail views A and B respectively to provide a clearer illustration of the tabs 21 and the relative positions of aris R and a tab 21 .

Figure 1 1 depicts the sequence of actions involved in planting pole P in the ground with anchorage and support being provided by attachment 10'. Figure 1 1 shows a pilot hole H that has been drilled or formed in hard and/or rocky ground W. The as-purchased pole/attachment 10' configuration is then driven or pressed firmly into Hole H. As pole P is driven down the bore 23 of metal tube 18, in the case of the ground being more rocky than hard the tabs 21 can fold outwards under pressure from aris R as it forced past the hinge area of the tabs 21. The right hand view in Fig 1 1 shows the pole P fully home in metal tube 1 8 and all of the tabs 21 folded out through the wall of metal tube 1 8, thus providing firm anchorage in the rocky ground W.

Figures 1 2 to 1 5 show the differing modes of action of the tabs 21 in ground of different composition. Figures 12 and 13 shows how the tabs 21 behaves when forced against the wall of a very hard hole and Figs 14 and 1 5 when in a looser hole. In fact, ground is often of a heterogenous nature with harder and softer material distributed in an unpredictable way

throughout the soil profile, so the ability of tabs such as 21 to provide strong frictional contact as shown in Figs 1 2 and 13 or toothed anchorage as shown in Figs 14 and 1 5, often within the same hole, is a distinct advantage.

Figure 16 shows a third embodiment of the attachment according to the present invention. This third embodiment is similar to that shown in Figs 1 -5 and therefore carries the same reference numerals for the equivalent parts.

According to this preferred form which preferably is moulded from a suitable plastic material and once again can either be moulded onto the pole P or post moulding can be fitted to the pole P and has wings 1 3 but with pre-formed curved distal ends 1 3a. Thus with the preformed ends 1 3a there is not the need to manually form the curve as is the case with the first embodiment.

The curved ends 1 3a of the wings 1 3 are preferably provided with a sharpened edge profile on their ends so as to ensure that the wings 1 3 will flare out as required and as described in relation to the first embodiment.

In this form of the invention the trunk 1 2 and the tapered section 1 1 is preferably of a grooved or fluted construction. As shown in Figures 16-19 this form of the invention has a series of longitudinally extended grooves 26. Not only does this provide for increased longitudinal rigidity but also increases resistance to lateral movement because there is a greater proportion of load bearing surface presenting square on to lateral forces.

This embodiment of attachment 10" has the primary blades 1 6 but also has secondary blades 16a. These are located at mutual right angles to the primary blades 16 and as illustrated are of overall less size. The secondary blades 16a provide resistance to sliding down at right angles to the fence line when the attachment is installed in the ground.

In each of the primary blades 16 there is provided a longitudinally extending slot 27. Extending from one side wall of the slot 27 is a pair of protrusions 28.

As shown in Figs 1 8 and 1 9 a plurality of the attachments 10" can be interlocked together which makes it useful for storage and transportation of a plurality of attachments generally with poles P connected thereto. To fix one attachment 10" to another attachment 10" the secondary blade 1 6a of one attachment is forced into a slot 27 of the other attachment 1 0" whereupon the protrusions 28 will lock into openings or depressions 29 in the secondary blade 16a.

Figures 20 and 21 are two views of a preferred embodiment of a rammer/extractor tool for planting, setting and removing posts and sleeves as described above and shown in Fig 1 to Fig 19. For convenience this tool will hereafter be referred to as a rammer.

The rammer 30 comprises a steel sleeve member shank 31 which is preferably blocked with a threaded end-cap 32 at its top end and tipped at its bottom end with an internally tapered driving-head 33. Solidly fixed to shank 31 are two pivot axles 34 and 35 and chain-lug 36. Gripping jaws 37 and 38 pivot about 34 and 35 respectively and are kept at a symmetrical angle to shank 31 by guide-pin 39 running in cam-slot 40.

Preferably a spring encourages one of the jaws 37 or 38 (and hence the opposing jaw as well) to swing to its lower limit of travel as indicated in the solid line representation of said jaws in Figs. 20 and 21.

Fulcrum leg 41 pivots about fulcrum pivot pin 42 and is fitted with fulcrum foot 43 to provide a broad stable base against which to lever. Throat 44 of foot 43 is slightly narrower than shank 31 but opens out into a larger orifice in foot 43, so that when leg 41 is swung forcefully toward shank 31 foot 43 snaps over shank 31 .

Figure 22 shows rammer 30 in its post-driving position with the attachment of the third embodiment sleeve 10" approximately at its full depth in the ground and pole P inside shank 31 which is preferably lined with a smooth plastic sleeve, liner 46. Preferably driving cap 33 overlaps tapered section 1 1 of sleeve 1 0" when the top of pole P strikes either end- cap 32 or a spacer member 45 within shank 31 .

Preferably, the bore of liner 46 is adapted to receive a variety of spacer members 45 to allow for a range of lengths of pole P to be efficiently driven with driving cap 33 overlapping tapered section 1 1 when pole P strikes spacer member 45. During the driving operation foot 43 is held snapped over shank 31 and jaws 37 and 38 are held inwards by a spring.

Figure 23 shows rammer 30 in the process of retracting attachment 10" from its driven position thus spreading wings 13 as curved ends 1 3a catch in the soil. Gripper jaws 37 and 38 are shaped so that they press against pole P with progressive force as shank 31 is levered upwards about fulcrum pin 42.

Preferably the jaws are shaped to substantially conform to the shape of pole P to avoid damaging pole P. When shank 31 is moved downwards jaws 37 and 38 automatically release from the surface of pole P so that they can take a fresh bite on pole P as they re-engage under the encouragement of a spring. The preferably large footprint of foot 43 ensures that the compressive forces exerted through leg 41 are resisted even in soft ground.

Figure 24 shows a preferred embodiment of pilot tool 47 which is used to pre-form a pilot hole in hard or rocky ground for attachment 10" Pilot tool 47 comprises blade 48 which is preferably made of hardened alloy steel. The main body of blade 48 is preferably tapered inwards toward its tip 49 so that it is less prone to jamming in hard rocky ground. At the upper end of 47 another tapered section, head 50, is provided which is shaped to nest inside internal taper of driving-head 33 attached to rammer shank 31.

The diameters of the internal taper in driving-head 33 and head 50 are such that when the end-face 51 of head 50 on the top of pilot blade 48 makes contact with the end face of driving-head 33 there is still a small amount of clearance between the tapered surfaces. This prevents head 50 from jamming inside driving-head 33 while still providing strong load bearing surfaces when rammer 30 is used to lever pilot tool 47 from side to side make a larger hole or straighten the pilot hole when blade 48 is deflected by rocks.

Pilot tool shank 52 is preferably constructed from high tensile steel and is screwed into head 50 of pilot-blade 48. Shank 52 is of a diameter which slides freely inside liner 46 and its functions are to guide head 50 into sleeve 33 and provide alignment of pilot tool 47 and rammer 30 when 30 is used as a slide hammer to extract pilot tool 47 from a pilot hole as depicted in Figure 25. Chain 54 is linked to blade 48 via hole 53.

Figure 25 shows pilot tool 47 and rammer 30 in mid-stroke when creating a pilot hole in hard ground. Rammer 30 slides up and down on shank 52 and pounds blade 48 into the ground as driving cap 33 impacts on face 51. During this process chain 54 hangs loosely and rests on the ground.

Figure 26 shows the method of extracting blade 48 from the pilot hole. Chain 54 is now attached to chain-lug 36 so that when rammer 30 is moved forcefully upward its momentum is transferred to blade 48 via chain 54 thus breaking the hold of the hard ground and allowing tapered blade 48 to be extracted from the pilot hole.

In the illustrated form of the invention the pole is indicated as being of circular cross section and the bore in the attachment will be of a commensurate shape. However, in other forms of the invention the pole could be of a non-circular cross-sectional shape and as a result a commensurate cross-sectional shape bore will be provided in the attachment.

In the embodiments of the attachments as disclosed herein the tapered end(s) of the attachment is shown to be smooth or as with a third embodiment provided with a series of grooves or flutes. In other forms of the invention the tapered end (more particularly the upper end) can be provided with a series of radial protrusions or fins. These would be of decreasing height toward the distal end so as to effectively form a tapering profile.

Other modifications and embodiments of the invention will be found to those skilled in the art and fall within the scope of the invention as defined by the appendant claims.