- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT ORIGINAL Name of Applicants: Greg Wheeler Contracting Pty Ltd Actual Inventor: Greg Wheeler Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: SECURITY FENCING SYSTEM, PALE, AND MOUNTING MEMBER Details of Original Application No. 2007200780 dated 21 Feb 2007 The following statement is a full description of this invention, including the best method of performing it known to us: File: 48990AUP02 -2 FIELD OF THE INVENTION The present invention relates to a corrugated fence pale, a securing member for a fence pale, and various systems and methods related to security fencing. The invention has been primarily developed for reducing the risk of unauthorised 5 access to enclosed areas by the removal of fence pales, and will be described herein by reference to that application. However, it will be appreciated that the invention is by no means limited to this filed of use, and is generally applicable in a broader context. BACKGROUND TO THE INVENTION Any discussion of the prior art throughout the specification should in no way be io considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. Corrugated fence pales are commonplace in the context of security fencing systems. In such systems, a fence support structure is erected and secured in the ground, the structure having a horizontal support member. Corrugated pales are securely attached is at laterally spaced locations on the support member, typically by way of bolts. Corrugated pales are regarded as particularly well suited to high security applications given longitudinal rigidity properties provided by a corrugated design. For example: a single bolt at an upper region often secures such pales, and the corrugated design substantially prevents a lower portion being upwardly bent to gain access to a 20 fenced area. Known security fencing systems that make use of corrugated pales are, nevertheless, subject to damage as a result of malicious tampering. The present inventor has identified a particular quality of known corrugated fence pales that presents a particular security risk. This security risk renders many known corrugated pales subject to being 25 easily removable following strong or repeated impact at or around a securing bolt. SUMMARY OF THE INVENTION It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.
-3 In accordance with a first aspect of the invention, there is provided an elongate corrugated fence pale for securely attaching to a lateral prismatic support member, the fence pale including: a pair of laterally spaced longitudinally extending corrugated portions; and 5 a longitudinally extending central web integrally laterally connecting the corrugated portions, the web having a substantially planar inner web surface for close conforming abutting engagement with a corresponding planar surface on the support member. Preferably the corrugated portions extend along substantially parallel longitudinal 1o axes. Preferably the pale includes a mounting aperture formed through the web portion for receiving a securing member engageable with the web portion and the support member. More preferably, upon secure attachment the securing member abuttingly engages with an outer web surface of the web portion. Still more preferably the outer web surface is 15 substantially planar. Preferably upon secure attachment the outer web surface is resiliently outwardly biased. Preferably the support member includes a formation for receiving the support member. Preferably in absence of secure attachment the corrugated portions corrugate between an outer lateral datum and an inner lateral datum spaced apart from the outer 20 lateral datum. More preferably the web is located intermediate the inner lateral datum and the outer lateral datum such that upon the secure attachment the respective outer edges of the corrugated portions are tensionally engaged with the corresponding surface of the support member. Preferably the separation dimension of the inner web surface from the inner lateral datum is less than about 10% of the separation of the inner lateral datum from 25 the outer lateral datum. More preferably the pale is constructed of steel having a substantially constant thickness dimension defined by the separation of the inner web surface from the outer web surface, and the separation dimension of the planar inner surface from the inner lateral datum is less than the thickness dimension. In some embodiments the separation dimension of the planar inner surface from the inner lateral 30 datum is less than about 50 % of the thickness dimension.
-4 Preferably each corrugated portion includes a pair of substantially planar arm portions converging toward and connected by a central curved portion. Preferably the inner web surface has a lateral dimension of at least 10% of the total lateral dimension of the pale. 5 According to a second aspect of the invention, there is provided a security fencing system including: an elongate corrugated fence pale for secure attachment to a lateral prismatic support member according to the preceding aspect; and a mounting member for securely attaching the pale to the prismatic support 10 member, the mounting member including: a shank insertable through a mounting aperture in the web; and a head integrally formed with the shank portion and being geometrically configured to substantially reduce the risk upon secure attachment of generally downward impact on head the separating the head with respect to the shank. is Preferably the head is substantially defined by a dome having a pair of opposite minor segments removed along substantially parallel chords. More preferably the head is substantially defined by a dome having four minor segments removed to define a substantially rectangular base periphery. In a preferred embodiment the dome has a central flattened uppermost region defining a planar top having a circular periphery. 20 In a preferred embodiment the head includes: a substantially planar inner surface for abutting engagement with an outer surface of the web upon secure attachment; and an outer surface substantially opposite the first surface having opposite edges respectively converging toward respective corresponding edges on the inner surface. 25 Preferably the opposite edges on the outer surface respectively meet the corresponding edges on the inner surface. More preferably the opposite edges on the outer surface are respectively spaced by less than about 3mm. According to a further aspect of the invention there is provided a mounting member for securely attaching a corrugated fence pale according to the first aspect to a prismatic 30 support member, the mounting member including: -5 a shank insertable through a mounting aperture in the web; and a head integrally formed with the shank portion and being geometrically configured to substantially reduce the risk upon secure attachment of generally downward impact on head the separating the head with respect to the shank. 5 Known corrugated fence pales leave air gaps proximal the mounting bolts when mounted to a fence in the conventional manner. The present inventor has found that such air gaps adversely affect the overall integrity of fencing systems that use such pales. In particular, hitting the bolt with a hammer deforms the pale into the air gap, which often loosens the bolt to a point where it is able to be removed by hand - even if a shear nut has 1o been used. In overview, embodiments of the present invention provide a fence pale that bolts to a fence rail without creating air gaps. This is achieved by using a pale with a central web having a substantially planar web for engaging, one a first side, the substantially planar opposed face of the head of a T-bolt and, on the other side, the substantially planar opposed face of the rail. That is, the head of the T-bolt is able to sit is flat against the pale, and the pale sits flush with the rail when the bolt is tightened. Embodiments of the invention include a specially designed T-bolt having tapered edges that make it difficult for an intruder to knock the end off the bolt using a cold chisel and hammer. According to a further aspect of the invention there is provided a method of 20 construction, the method including: providing a mounting member for use in a security fencing system, the mounting member including: a shank portion insertable through a mounting aperture; and a head integrally formed with the shank portion, the head being substantially 25 defined by a dome having four minor segments removed to define a substantially rectangular base periphery and thereby to provide a deflection rated curvature and small purchase area for substantially reducing the risk upon secure attachment of generally downward impact on the head separating the head with respect to the shank, wherein the dome has a central flattened uppermost region defining a planar top having a circular 30 periphery; and - 5a using the mounting member to secure an elongate corrugated fence pale to a lateral prismatic support member, wherein the fence pale includes: a pair of laterally spaced longitudinally extending corrugated portions; and a longitudinally extending central web integrally laterally connecting the 5 corrugated portions, the web having a substantially planar inner web surface for close conforming abutting engagement with a corresponding planar surface on the support member, wherein in absence of secure attachment the corrugated portions corrugate between an outer lateral datum and an inner lateral datum spaced apart from the outer lateral datum, the web being located intermediate the inner lateral datum and the outer 1o lateral datum such that upon the secure attachment the respective outer edges of the corrugated portions are tensionally engaged with the corresponding surface of the support member. BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention will now be described, by way of is example only, with reference to the accompanying drawings in which: Figure 1 is a schematic representation of a fencing system including a corrugated fence pale in accordance with an embodiment of the present invention; Figure 2 is a schematic representation of the pale of Figure 1; Figure 3 is a cross-section of the pale of Figure 1; 20 Figure 4 is a cross section of the pale of Figure 1 shown securely attached to a support member; Figure 5 is a to view of a securing member used in Figure 4; Figure 6 is a side view of the securing member of Figure 5; Figure 7 is an end view of the securing member of Figure 5; 25 Figure 8 is a further end view of the securing member of Figure 5; -6 Figure 9 is a cross sectional view of a prior art corrugated fence pale securely attached to a support member; Figure 10 is a similar view to Figure 9, showing the prior art corrugated fence pale deformed; 5 Figure I1 is a schematic diagram of a fence pale cross section in accordance with an embodiment of the invention; and Figure 12 is a schematic diagram of a securing member in accordance with an embodiment of the present invention. DETAILED DESCRIPTION 10 Referring to the drawings, and in particular Figures 1 to 4, there is provided a corrugated fence pale 1 for secure attachment to a lateral prismatic support member 2. Pale 1 includes a pair of laterally spaced longitudinally extending substantially parallel corrugated portions 3 and 4. A longitudinally extending central web 5 integrally laterally connects corrugated portions 3 and 4. Web 5 has a substantially planar inner web surface 6 is for close conforming abutting engagement with a corresponding planar surface 7 on support member 2 upon secure attachment of the pale to the support - as best shown in Figure 4. In the present embodiment, a purpose-designed securing member 8 provides the secure attachment between pale 1 and support 2. This securing member is dealt with in 20 greater detail further below. In overview, pale I is used as part of a security fencing system 9. It will be recognised that fencing system 9 is designed to prevent passage in direction 10. System 9 includes a structural steel frame 11, and this includes horizontal support 2. More specifically, support 2 extends between vertical support members 12 and 13, 25 which in use are typically set in concrete 14. Frame 11 therefore provides a general secure structure, which is not easily removed or damaged. Pales 1 are attached at spaced lateral locations on support 2, using a single securing member 8 for each pale. Typically, each location on support 2 is defined by a mounting aperture 15 for receiving a respective securing member 8.
-7 Pales 1 are spaced along support 2 from member 12 to member 13 to provide a barrier to passage in direction 10. In the present embodiment each pale I includes an upper deterrent region 18 to deter persons from attempting to scale the fence. Various deterrent regions are used in embodiments, and many options will be known by those 5 skilled in the art. In some cases razer or barbed wire connects regions 18 of adjacent pales 1 as an added deterrent. In further cases, regions 18 are bent in a direction generally opposite direction 10. As best shown in Figures 5 and 6, member 8 includes a threaded shank 20 integrally connected to a head 21. In use, the shank is inserted in direction 10 through a 1o mounting aperture 22 in pale 1, and then through an aperture 15 in support 2. A shear-nut 23 is then threadedly engaged with the shank and tightened to securely attach the pale to the support, and bring surface 6 into close conforming abutting engagement with surface 7. This in turn brings an inner surface 24 of head portion 21 into engagement with a substantially planar outer web surface 25, and an inner nut surface 26 into engagement is with an outer support surface 27. Upon sufficient threshold tightening of shear-nut 23, a frangible unthreaded engagement portion 28 shears from a non-engagement threaded portion 29. This non-threaded portion is then loosely slidably removable from the shank in direction 10. Portion 28 is smooth and not easily grasped for turning, making it difficult to remove even with a shifting spanner or socket. This will be appreciated by those familiar 20 with shear-nuts in general. The shearing of portion 28 defines the secure attachment of pale 1 to support 2. Shear nut 23, and indeed member 8, is formed of stainless steel. The rationale for using stainless steel as an alternative to galvanised coated steel relates to the shearing of portion 28. In particular, if a galvanised shear nut were used, the shearing of portion 28 25 would expose an uncoated steel portion that is subject to corrosion. This corrosion reduces the efficacy of pale attachment, and the integrity of a fencing system on the whole. Pale I is typically manufactured using conventional steel bending techniques in the first instance to provide the corrugations and web to a per-cut length of steel. Following bending, aperture 22 is formed, and region 17 shaped in the desired configuration.
-8 Figures 9 and 10 illustrates a prior art corrugated fence pale 30. This prior art pale is continuously curvaceously corrugated, and secured to support 2 at a curved region 31. When secured to support 2 using a similar support member 8 and shear-nut 23, air pockets 33 and 34 are defined. It has been recognised by the present inventor that these air pockets 5 create a risk of pale insecurity. In particular, if an object strikes head 21 or region 31, pale 30 often deforms around these air pockets, as shown in Fig. 10. This reduces the distance 37 of surface 38 from surface 27, however, with the reduction of distance 37, there is no corresponding reduction in the distance 40 between surfaces 24 and 26. It will be appreciated that the deformation in Fig 10 is somewhat exaggerated to io illustrate the point in question. The difference in distances 37 and 40 effectively loosens member 32. This increases the likelihood that portion 25 is removable by hand, which would allow removal of pale 30. It also creates a weakness that results in easier separation of head 21 from shank 20 - for example upon strong impact with a hammer. is As shown in Figure 4, upon secure attachment of pale I to support 2, surfaces 6 and 7 are in close conforming abutting engagement. As a result, there are no air pockets, and it follows that a variance between the corresponding distances 37 and 40 is less probable. It follows that the abovementioned security risks associated with such air pockets are alleviated or indeed circumvented by pale 1. 20 Pale I is further configured to reduce the risk of variation between distances 37 and 40 by a tensioned attachment approach. Specifically, upon secure attachment, surface 25 is resiliently outwardly biased into surface 24. This is achieved by design of portions 3 and 4, as discussed in greater detail below. In absence of secure attachment, as shown in Fig. 3 corrugated portions 3 and 4 25 each corrugate between an outer lateral datum 45 and an inner lateral datum 46 spaced apart from datum 45. Web 5, and specifically surface 6, is located intermediate datum 45 and datum 46. It follows that the respective outer edges 47 and 48 of portions 3 and 4 become progressively tensionally engaged with surface 7 as securing member 8 is tightened to securely attach the pale to the support. Upon secure attachment, marked by 30 the shearing of portion 28, surface 25 is resiliently outwardly biased into surface 24. As a -9 result, a slight deformation of web 5 and/or support 2 is allowable without resulting in variation of distance 37 from distance 40, given that the lateral tension in pale 1 causes distance 37 to increase to match distance 40. This approach is additionally effective in reducing the risk of portion 29 from becoming readily manually removable as a result of 5 vibration, temperature related expansion or contraction, or other similar effects. Further, the tension substantially prevents a chisel or similar device being wedged intermediate surfaces 24 and 25. In a preferred embodiment the separation dimension 49 of surface 7 from datum 46 is less than about 10% (or more preferably less than 5%) of the separation datum 45 from io datum 46. This sizing option presents an advantageous balancing between the amount of force required to tighten nut 23 and provide hence secure attachment and the amount of resilience provided. Dimension 49 is also preferably selected by reference to the malleability of steel used to create pale 1. This malleability affects the extent to which deformation of web 5 is possible even without air gaps. is In a specific embodiment, the separation of datum 45 from datum 46 is 18.90mm, and separation dimension 49 is 6mm. In this embodiment, pale I is formed of G250 steel having a substantially constant thickness of about 3.0mm. This presents a particularly suitable balance - it will be appreciated that as the thickness of steel increases the amount of force required for secure attachment correspondingly increases for a given dimension 20 49, however the extent to which the steel is able to be flattened also increases. Each corrugated portion 3 and 4 includes a respective pair of substantially planar arm portions 51 and 52 converging toward and connected by a central curved portion 53. Of specific note, planar outer arm portions 51 result in a beneficial transference of tensional force from the corrugations to the web upon tensioned engagement and secure 25 attachment. Specifically, the extent to which force causes irregularity in surface 6 is reduced. In any event, it is typically preferable to select an appropriate lateral dimension for web portion 5. This should be sufficiently large to allow for some bending in web 5 without the formation of air pockets behind the bolt, as in the prior art. However, if the 30 web is too laterally wide, this results in substantial purchase being available for a lateral or -10 diagonal downward strike on head 21. There are also considerations relating to preserving a threshold level of longitudinal rigidity in pale 1. In a preferred embodiment the web itself, and specifically surface 5, has a lateral dimension 55 of at least 10% of the total lateral dimension 56 of pale 1. Typically a dimension 55 of between 15% and 25 % of s dimension 56 is advantageous. In one embodiment, the total lateral dimension is 71.34mm, and the lateral dimension of surface 6 is 13.00mm. In some embodiments the corrugated portions are not parallel, and as such dimensions 55 and 56 vary along pale 1. In such cases the important dimensions to consider are those at the height of aperture 22. to Figures 6 to 8 illustrate securing member 8 in greater detail. Shank 20 and head 21 are integrally formed from hardened stainless steel, such as AISI-304. An important feature is that head 21 is geometrically configured to substantially reduce the risk upon secure attachment of generally downward impact on head the separating the head with respect to shank 20. In the present embodiment this is achieved by a combination of two 15 approaches: e Providing a general deflection rated curvature on the outer surface 60 of head 21. The general notion is that an object striking surface 60 should deflect such that the majority of striking force is prevented from affecting member 8. * Providing a reduced separation of surface 60 from surface 24 at upper and 20 lower ends 61 and 62 of head 12 to reduce the purchase area available for upward or downward impact upon secure attachment. As shown in the Figures, in use ends 61 and 62 are vertically spaced in alignment with the general axis of pale 1. In a preferred embodiment the edge spacing of surfaces 60 and 24 at ends 61 and 62 is less than about 3mm. An edge spacing of between 20% and 25 80% of the maximum spacing between these surfaces is generally preferred, however in some cases the spacing is less than this. In one embodiment, surfaces 60 and 21 meet at each end 61 and 62 to further reduce purchase availability. However, in such an embodiment it is advisable to use particularly non-malleable steel. The rational is that impact at either of ends 61 and 62 is may cause deformation at these thinner regions, which 30 could in turn provide a surface for purchase.
- 11 As best shown in Figure 8, head 21 is substantially defined by a dome having a two pairs of opposite minor segments 64 and 65, and 66 and 67, removed along substantially parallel chords 67 and 68, and 69 and 70. This defines a substantially rectangular base periphery. Width dimension 71 and height dimension 72 are typically selected on the basis 5 of general strength considerations and the width of web 5. In particular, dimension 71 should be less than the width of web 5 such that head 21 fits in the channel defined between corrugated portions 3 and 4. The closer the side edges 73 and 74 of heads 21 to portions 3 and 4, the less horizontal purchase available. However, as if too close, there is a risk of tension induced air pocket effects. Preferably a dimension 71 of about 70% to 90% to of the width of web 5 is chosen. In a specific embodiment dimension 71 is about 10mm, and the width of web 5 is about 13mm. Height dimension 72 should be greater than the width of web 5 to facilitate convenient tightening of nut 23. In the mentioned specific embodiment dimension 72 is about 16mm. In some embodiments minor segments 66 and 67 are not removed such that is curvature continues to the edge where the outer and inner surfaces meet. The dome has a central flattened uppermost region 75 defining a planar top having a circular periphery 76. This, although planar, is nevertheless beneficial from a deflection perspective given that it is vertically displaced in use. That is, a vertical surface provides the least purchase for vertical impact. Indeed, vertically speaking purchase is only 20 substantially available at ends 61 and 62, which are small, and along regions 77 and 78, where there is curvature-based deflection. Horizontal purchase is less of a concern given the protection provided by portions 3 and 4. It will be appreciated that the combination of a planar inner web surface, resilient mounting, and purchased minimizing mounting hardware combine to allow construction of 25 a particularly tamper resistant security fence 9. That being said, these features on their own provide individual and distinct advantages over known art. Although the invention has been described with reference to a specific example, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. 30