HEWITT, Stephan (32 Computer Road, Yatala, QLD 4207, AU)
| CLAIMS: 1. A picket post for use in forming a fence or the like, the picket post defining a central longitudinal axis and at least three flanges extending away from the central axis, the picket post defining a ground engaging end and an opposite end, and wherein at least one of the flanges preferably defines one or more apertures for attachment of wire or the like thereto, characterised in that the post is made of a plastics material and that the flanges are kinked or bent. 2. The picket post as claimed in claim 1 wherein the picket post is rotationally symmetrical about it's central axis and the angle between each adjacent flange at the central axis is 120°. 3. The picket post as claimed in 1 or claim 2 wherein each flange defines a first portion extending away from the central axis in a radial direction and a distal second portion which is oriented at an angle of between 80° to 120° to the first portion. 4. The picket post as claimed in claim 3 wherein the second portion is oriented at an angle of between 90 to 110° to the first portion 5. The picket post as claimed in claim 4 wherein the second portion is oriented at an angle of about 100° to the first portion. 6. The picket post as claimed in any one of claims 3 to 5 wherein the length of the second portion of each flange between one and a half and two times the length of the first portion of the flange. 7. The picket post as claimed in any one of claims 1 to 6 wherein the flanges of the picket are approximately 4 to 6mm in thickness. 8. The picket post as claimed in any one of claims 1 to 7 wherein the flanges of the picket are approximately 5mm in thickness. 9 The picket post as claimed in any one of claims 1 to 8 wherein the picket post made from PVC, preferably modified PVC. 10. The picket post as claimed in any one of claims 1 to 9 wherein the ground engaging end defines a point or spike and the opposite end is flat. |
Cross-Reference to Related Applications
The present application claims priority from Australian patent application No 2010903427 the entire content of which is incorporated herein by reference.
Field of the Invention
This invention relates to a picket post for use in fencing and the like.
Background of the Invention
Star pickets or picket posts are multi-purpose metal stakes which are most often used as upright posts for fencing, but also have other uses such as for forming barriers for cordoning off areas and may also be used as stakes to support growing trees and vines and the like.
Star pickets typically have a three pointed star shaped cross-section (hence the "star picket" name) with an angle of 120° between each flange/arm of the star. Each post has a pointed end for penetrating ground and a generally flat top end. At least one of the flanges of the post will define a series of spaced apart holes for receiving fencing wire or the like. In use, the pointed end of the picket is driven into the ground by hitting the flat end of the picket with a sledge hammer or the like, or by using a purpose built picket driver.
Because steel pickets are a relatively inexpensive and effective form of fencing and are relatively quick to install, they are very commonly used in rural areas for temporary or permanent fencing. They can also be removed from the ground relatively easily where temporary fencing is to be installed. Steel pickets may, in some cases, be used in areas where mining is carried out. However, there is a problem with using steel picket posts on a mining site and/or in mines themselves as if the posts become mixed in with mined ore or coal they could cause serious and costly damage to mining machinery used to treat or transport the ore/coal such as conveyors, crushers and the like.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application. Summary of the Invention
In a first broad aspect the present invention provides a picket post for use in forming a fence or the like, the picket defining a central longitudinal axis and at least three flanges extending away from the central axis, the picket defining a ground engaging end and an opposite end, and wherein at least one of the flanges preferably defines one or more apertures for attachment of wire or the like thereto, characterised in that the post is made of a plastics material and that the flanges are kinked or bent.
The picket is preferably rotationally symmetrical about it's central axis. The angle between each adjacent flange at the central axis is 120°.
Each flange may define a first portion extending away from the central axis in a radial direction and a distal or second portion which is oriented at an angle of between 80° to 120° , typically 90 to 110°, most preferably around 100° to the first portion.
The length of the distal portion of each flange is typically around one and a half to two times the length of the first portion of the flange.
Typically, the flanges of the picket are approximately 4 to 6mm in thickness, preferably around 5mm.
The material used for making the picket is preferably modified PVC material which includes an impact modifier which improves the ductility and fracture toughness of the PVC material, although other plastics materials may be suitable.
Brief Description of the Drawings
A specific embodiment of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: - Figure 1 is an isometric view of a picket embodying the present invention;
Figure 2 is a front view of the picket shown in Figure 1 ;
Figure 3 is a top plan view of the picket shown in Figure 1 ; and
Figure 4 is an underneath plan view of the picket shown in Figure 1.
Detailed description of the preferred embodiment
Referring to the drawings, Figures 1 to 4 show a picket post 10 embodying the present invention. The post defines a central longitudinal axis L, (best seen in Figures 1, 3 and 4) from which extend three flanges or legs 12 (refer to Figures 3 and 4). As is best seen in Figures 3 and 4, the legs or flanges 12 are bent so that in cross-section the picket defines a triskele.
With reference to Figure 4, each flange defines a first portion 14 which extends away from the axis L is a radial direction and a second portion 16 which extends at an angle a of 100° to the first portion. The first portion 14 is typically about 10mm long and the second portion 16 about 20mm long. The distal ends of the flanges are rounded. The flanges have a transverse thickness t of about 5mm. The specific dimensions may be varied. In cross section, the triskele is rotationally symmetrical and the angle between each adjacent pair of flanges where they meet at the axis L is 120°.
The post is preferably made from modified PVC and is solid, although other suitable plastics materials may be used.
As is best seen in Figure 2, the post defines a pointed ground engaging end 20 which is used is pushed into ground, although the very tip 26 of the post is flat. The opposite top end 22 is generally flat and can be struck with a mallet or the like for forcing the post into ground. The end 22 may also be engaged with a a purpose built picket driver for pushing the picket into ground.
As is best seen in Figures 1 and 2 one of the flanges 12 defines three spaced apart apertures 28, 30, 32 for attachment of wire or the like to the flange. One of the apertures 28 is near the tip 20 of the picket, one 30 in approximately the middle and one 32 near the top 22.
In use, the pickets may be driven into ground with a mallet or the like and used to fence off areas using wires or the like strung between the posts. The shape of the posts means they can offer sufficient strength and rigidity which is at least comparable to a steel post (but without the rusting that afflicts steel), and is typically 25 to 30% better than any existing plastic pickets. Further being made of plastic they should not damage mining machinery if accidentally caught up with dug up coal ore or the like and therefore can be safely used in mining environments including in or near areas which are intended to be mined.
It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.