Patent Publication Number: US-2021161081-A1

Title: Trellis Posts

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of International patent application No PCT/AU2019/050766, filed on 23 Jul. 2019, published as WO 2020/019021, and entitled “Improvements in Trellis Posts” which in turn claims priority from Australian provisional patent application no 2018902652 filed 23 Jul. 2018, the entire contents of all of which are herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to improvements in posts, particularly trellis posts. 
     BACKGROUND OF THE INVENTION 
     Trellis posts are commonly used in vineyards for carrying wires on which vines are trained. Vineyards can be harvested by hand or by machine. Where machine harvesting is carried out the trellis need to be resilient to being struck by machinery. 
     Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification 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 disclosure as it existed before the priority date of each of the appended claims. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention there is provided a trellis post comprising a moulded plastic tubular element defining a central post, the central post providing an interior and defining two flanges extending from opposed sides of the central post, the flanges extending along the length of the tubular element, the flanges defining a series of spaced apart slots for receiving wires and wherein the trellis post defines a ground engaging means at one end; and wherein the moulded plastic tubular element is reinforced with an internal stake extending through the interior of the post and a supporting/filling material is located between the stake and the interior of the central post, wherein the supporting material is selected from the group consisting of a foamed plastics material, mortar, concrete, and Portland cement. 
     Typically the moulded exterior of the post is made from PVC. 
     It is preferred that the stake is wooden, and is typically pine. 
     The foamed plastics material is preferably foamed polyurethane. 
     Typically the ground engaging means is a spike. The spike may be moulded from any suitable material and the preferred materials include HPDE, polycarbonate, Nylon and polypropylene, with HPDE being the most preferred material. 
     The moulded plastic tubular element is preferably made by extrusion. 
     The spaced apart slots typically extend downwardly at an angle from an open end towards the centre of the post when the post is vertically oriented in use. 
     The invention also encompasses a method of making a trellis post comprising the steps of; 
     forming a moulded plastic tubular element comprising a central post defining an interior and two flanges extending from opposed sides of the central post, the flanges defining a series of spaced apart slots for receiving wires; 
     pouring a foamed plastics material, concrete, mortar or portland cement mix into the central post; and 
     inserting a reinforcing stake into the interior. 
     In a related aspect, the invention also encompasses a method of making a trellis post comprising the steps of; 
     forming a moulded plastic tubular element comprising a central post defining an interior and having open ends and defining two flanges extending from opposed sides of the central post, the flanges defining a series of spaced apart slots for receiving wires; 
     inserting a reinforcing stake, typically made of wood, into the interior of the tubular element; 
     closing the ends of the tubular element with a cap on one end and a ground engaging spike on the opposite end, the spike and cap defining one or more protrusions for engaging with the tubular element, at least some of the protrusions being tubular and allowing for the injection of foamed material therethrough; 
     pouring a foamed plastics material, or optionally concrete, mortar or portland cement mix, into the central post through the tubular protrusions to fill the interior of the post. 
     Typically the reinforcing stake is secured to the cap and to the spike using fasteners prior to filling of the interior of the post. 
     The invention also provides a post made according to the above method. 
     Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Specific embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: 
         FIG. 1  is a front view of a post embodying the present invention; 
         FIG. 2  is a side view of the post of  FIG. 1 ; 
         FIG. 3  is an enlarged front view of the ends of the post; 
         FIG. 4  shows a section through the post of  FIG. 1 ; 
         FIG. 5  is a top view of the post; 
         FIG. 6  is a section on A-A of  FIG. 5 ; 
         FIG. 7  is an isometric view of an alternative top cap for the trellis post; 
         FIG. 8  is a bottom view of the alternative top cap shown in  FIG. 7 ; 
         FIG. 9  is an isometric view of an alternative bottom end of the trellis post; 
         FIG. 10  is a bottom view of the alternative bottom end shown in  FIG. 9 ; 
         FIG. 11  is a sectional view through the second embodiment of the trellis post; and 
         FIG. 12  is a section on A-A of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings,  FIGS. 1 to 3  show a trellis post  10 . The trellis post comprises a tubular element in the form of a moulded (extruded) plastic tube  12  which defines a central hollow post member  14  from which two flanges  16  and  18  project on opposed sides. The flanges and post member are integrally moulded, most preferably from PVC, although other thermoplastic materials such as HPDE or PP or PET could be used. As is best seen in  FIG. 3 , a series of slots  20  are defined in the flanges, typically spaced about 100 mm apart for receiving wires for trellising vines and the like. As shown in  FIG. 3 , the spaced apart slots extend downwardly at an angle from an open end of the slot towards the centre of the post when the post is vertically oriented in use, however the shape of the slots is not critical and may be varied from that shown. 
     As is also best seen in  FIG. 3 , the top of the extrusion is closed with a cap  22 , which may be made of any suitable plastics material. A ground penetrating spike  24  is attached to the base of the extrusion. The spike  24  is also typically made from a moulded plastics material such as HPDE although it could also be made from other materials, including metals. 
     With reference to  FIG. 4 , it can be seen that the PVC extrusion is reinforced with a foamed plastics filling  26 —most preferably foamed polyurethane, and a square timber/wooden stake  28 , most typically made from pine. As shown in  FIG. 6 , it can be seen that the opposed corners of the post are aligned with the flanges  16 ,  18 . 
     The use of the polyurethane foamed filling and strengthening timber stake results in the trellis being stronger and more resistant to bending while still allowing some flexing of the post without damage. In particular the stake increases the stiffness of the post, which is advantageous when the wires carried by the post are loaded with fully grown vines. The stake also assists in maintaining the rigidity of the post when the post is first driven into ground. 
     In order to manufacture the trellis post, the PVC extrusion  12  is first extruded and cut to size. Next one end of the extrusion is closed, typically with the spike  24 , but alternatively with the cap. An amount of foamed polyurethane  26  is them poured into the extrusion and the timber stake  28  is then inserted into the extrusion and the PVC foam is allowed to set. The foamed polyurethane acts as a filler between the stake and the extrusion. The polyurethane foam is made by mixing a 2-part iso/polyol combination and inserting it under relatively low pressure into the post. A dedicated “foaming” or foam injection machine is used for the process. The extrusion is then closed with the cap  22 . 
     Alternatively, instead of the filler being a foamed polyurethane, mortar, concrete, Portland cement, or other similar material may be used which acts to fill the gap between that stake and the post and further stiffens and strengthens the trellis post. 
       FIGS. 7 to 12  illustrate a variant of the trellis post and method shown in  FIGS. 1 to 6 . 
       FIGS. 7 and 8  illustrate a cap  110  which has a circular top  112  and a depending skirt portion  114  from which two opposed flanges  116  and  118  extend. In the centre of the cap there is a countersunk aperture  120  for receiving a fastener, such as a coach screw. Four tubular tabs/protrusions  122  whose top ends  124  are open to the top  112  of the cap, depend down from the top of the cap. 
       FIGS. 9 and 10  illustrate a variant of the spike  130 . The spike defines four protrusions or tabs  132  which engage with the extruded body of the post. As is best seen in  FIG. 10 , the base of the spike defines a countersunk aperture  134  in its centre for receiving a fastener, such as a coach screw. 
       FIGS. 11 and 12  show the manufactured and completed trellis post  100 . In order to manufacture the trellis post  100 , a PVC extrusion  140  substantially identical to the extrusion  12  is first extruded and cut to size. Next one end of the extrusion is closed with the spike  130 , but alternatively could be closed with the cap  110 . A square timber/wooden stake  150 , most typically made from pine, is inserted into the extrusion and enclosed within the extrusion by attaching the cap or spike. A fastener, such as a coach screw  152  is driven into each end of the timber stake  150  through the respective apertures  120 ,  134 . An amount of foamed polyurethane  154  is them injected into the extrusion via the tubular protrusions  122  in the top of the cap and the PVC foam is allowed to set. The tubular protrusions are designed to distribute the urethane foam evenly down and around the timber stake and fill the extrusion. 
     It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.