Improved palisade pale

Abstract

A palisade pale includes an elongate sheet of steel formed into a W or V cross-section. The pale comprises an elongate cut 26 at one end to provide divergent end points. The elongate cut comprises an inwardly curved portion 27. The inwardly curved portion may be adjacent to the base 26B of the elongate cut. The pale may have a W or V cross-section. The outer elongate edges (31, Figure 3) of the pale may be formed with a fold back (or Dutch bend) in the material. The pale may be formed form mild steel by cold rolling. A method for forming a palisade pale of W or V cross-section having an elongate cut with an inwardly curved portion includes creating the elongate cut in a pre-formed W or V cross-section pale using a punch (40, Figure 4). The punch comprises a knife 48 and a curved shoulder portion to form the inwardly curved portion of the elongate cut of the pale.

Description

The present invention relates to an improved Palisade pale for use in a palisade fence. 5 Palisade fences are widely used in security applications and comprise posts secured into the ground, horizontal rails between the posts and upon the rails a number of vertically aligned pales to provide a barrier between the posts. The pales are to be configured to start a few centimetres above ground level and to terminate at an upper end usually with some form of termination which io assists in the security function. A typical termination of a palisade pale is in a point, a subsection of this is termination with three points for additional security. These three points can be formed by providing longitudinal incisions in a preformed pale which cause the ends of the pale to splay outwards, typically in a continuous outward curve. A 15 typical cross-section for such pales is of a nominal W-cross-section with the longitudinal incisions at the two apexes of the cross-section. For these types of products it is desirable to use a range of qualities of material, such as strip steel, since exact dimensions are not particularly critical and precise feedstocks are more costly. This can give real rise to issues during production were 20 changes in steel thickness or degree of deformation occur. The relevant context is that a cross-section is typically formed from sheet deformed over a series of rollers, the rollers changing profile over time with wear and due to heating from ongoing use, as well as variation of thickness of feedstock material. Those changes in the formed pale before incision can give significant 25 variation in the curvature and splay of the points formed. This provides variation and hence portions of a fence which may be less secure than other portions. It is also undesirable and aesthetic perspective and more significantly Palisade fences are typically supplied as a kit of parts with the individual members, such as the pales, being stacked and variations in the end points so mean that stacking is not efficient, potentially leading to stacks tipping over and spilling, which is hazardous given that the pales have intrinsically sharp ends. There is therefore a need for an improved means of forming and formed palisade fence pale which provides more consistent end points, particularly when the dimensions and quality of the steel used and the precise form of the 35 cross-section may change during production. Known prior disclosures include GB 2573388 and GB 2307253, which disclose palisade fence end points. The present invention is set out in the appended claims. 07 02 24 The present invention provides 5 A palisade pale (20) comprising an elongate sheet of steel formed into a W or V cross-section, the pale comprising: an elongate cut (26) at one end to provide divergent end points wherein; the elongate cut (26) comprises an inwardly curved portion (27) adjacent to the base (26B) of the elongate cut, wherein the inwardly curved portion (27) forms an indentation along a portion of the base io edges of the elongate cut (26) being where cut finishes. This provides a palisade pale with a more consistent and form and provides improved security for final use by being more consistent in form. A W or V cross-section refers to a cross-section of such notional shape and is not 15 differentiated from what might be considered an M or, potentially even U, respectively, cross-section, this cross-section providing at least two outer edges and an inner apex, i.e. a portion which in cross-section can be considered at a higher point than the outer edges. For a W or M cross-section there are two apexes bordering a central trough. 20 In the present invention the inwardly curved portion is adjacent the base of the elongate cut. This has been found to provide the most reproducible results. Further work hardening by forming this bend as a separate pressing step provides for stronger lateral points for the pale. 25 In the present invention the cross-section is preferably a W cross-section. This provides the classic three points for a palisade fence and gives effective security. The present invention the cross-section may be a V cross-section. This provides a more compact form of pale which can be more closely spaced so such as were gaps between pales need to be minimised, for example as a barrier for the movement of animals. The present invention also provides a pale having the outer edges formed with a Dutch bend (fold back) in the material. 07 02 24 This gives the narrower (for a W section) outer points (prongs) of the pale additional rigidity and allows the inward curve shape to be retained even when stressed, such as when the point is impacted. This giving more robust handling preinstallation and even greater strength in use to that already achieved by the 5 inward curve. Also, during a method of manufacture including a cutting action the underside of the apex of the V or W needs less support for a given thickness of steel so that the cross-section does not crumple under the action of a cutter particularly when after prolonged use the cutter may become dull. The palisade pale of the present invention, being of W of the cross-section and io therefore providing what may be considered wings (either side of each V) wherein the wings of the pale have a deformation from planarity. This may be in the form of a protrusion (see figure 3) or a shoulder, i.e. a lateral offset from planarity. This provides additional rigidity particularly to the outer, narrower, points of the three pronged pale end. This additional rigidity is helpful during 15 the method of production as in a pressing step that support is required for the apex of the or W, as mentioned above. Hence the use of the Dutch band or the deformations (such as protrusions or shoulders) are both helpful and may be used individually or in combination with the form and method of the present invention. 20 The preferred material of the present invention is mild steel or stainless steel, the most preferred material of the present invention is mild steel this giving regular deform ability in a punch press to readily form the inward curve. Specifically, the use of mild steel provides good deform ability for the form ink of the shape but also work hardening to provide the greatest benefit from the 25 inward curve, particularly when at the base of the elongate cut where it serves to stiffen the (typically thinner if a W cross-section is used), outer prongs. The present invention also provides a method of forming a palisade pale comprising providing an elongate sheet of metal formed into a W or V crosssection, the elongate sheet being cut at one end to provide diverging end 30 points, the cut being made so as to provide an inwardly curved portion of the cut. The method of the present invention further comprises creating the elongate cut using a punch for creating the cut, the punch comprising a curved portion to form the inwardly curved portion of the elongate cut of the pale. 07 02 24 This enables an inwardly curved discontinuity to be created in a single action with the forming of the elongate cut. This provides more efficient production and more reproducible product form due to a separate bend forming step being avoided. 5 The method of the present invention preferably utilises a pale with a W crosssection. This is preferable as this section is inherently stable when inserted into a punch as it has a wide base footprint. The method of the present invention may utilise a pale with a view crosssection. This provides, with a single central elongate cut. io The method of the present invention preferably utilises a punch with a graduated cutting action were in the blade impinges upon the portion of the final elongate cut most remote from the end of the pale and proceeds to cut against a die in the direction of the end of the pale were in on completion of the cutting action the punch contacts the dye fully and forms the curved 15 portion of the elongate cut. The present invention is illustrated by means of the following drawings in which: Figure 1 shows a prior art Palisade pale of W cross-section and having to linear elongate cuts forming three points; 20 Figure 2 shows a palisade pale of W cross-section according to the present invention having a curved portion in the elongate cut forming the three points; Figure 3 shows a palisade pale W cross-section indicating the preferred positions of the elongate cuts to form the three points; Figure 4 shows a punch for forming the endpoint, the elongate cuts and the 25 inwardly curved portion; Figure 5 shows a punch for forming the elongate cuts with the inwardly curved portion; and Figure 6 shows a point for forming the inwardly curved portion alone. Diagram features: 30   10 - pointed end of prior art pale 12 - central point of prior art pale 07 02 24 14 - left (from front) point of prior art pale showing continuous curve 15 - right (from front) point of prior art pale showing continuous curve 16 - elongate cut of prior art pale noticing that cut on the right-hand side is shorter than that of the left-hand side. 5   18 - apex of W section of pale (right-hand side) 19 - central trough of W section pale. 20 - pointed end of pale of the present invention 22 - central point of pale 24 - left (from front) point of pale of the present invention io 25 - write (from front) point of pale of the present invention 26 - elongate cut of pale of the present invention noticing inwardly curved portion 27 26B - base of the elongate cut remote from the end of the pale. 27 - inwardly curved portion of elongate cut 15   28 - apex of W section of pale 29 - central trough of W section pale 30 - cross-section of W section pale suitable for forming the present invention 31 - end of W section pale, in this diagram folded back in a Dutch bend. 32 - central trough of W section pale 20   33 PO - outward wing protrusion on left wing of W section pale 33 PI - inside wing protrusion on left wing of W section pale 34 - apex of left wing of W section profile 36 -position of elongate cut suitable for you forming the present invention 37 - an elongate, support, member with a rounded end (illustrative of position 25 in punch 40). 38 - outer edge of wing of W section profile of the present invention showing preferred Dutch bend to adjust the probability of outer point 07 02 24 40 - first form of punch with graduated cutting action for forming the points (prongs) of the pale and with elongate cut having inward curve of the present invention 42 upper die of punch (movable) 5   44-lower die of punch (static) 46 - cavity in lower die for disposal of optional cut out 48 - knife of upper die showing inclined surface 50 - upper former of inward curve on punch 52 - lower former of inward curve on punch io 54-trim blade 56 - preferred direction of feed of pale into the punch, necessary if trim blade 54 is used. 58 - second form of punch suitable for the method of the present invention. 60 - third form of punch suitable for the method of the present invention. 15 Referring now to the figures of the present invention: Figure 1 shows a prior art pale with elongate end cut forming three points in the pale. The and this is consistent with the left and right points 14, 15 of the pale formed with an elongate cut 16 of uniform type and as can be seen on this example the cuts are of different lengths. This illustrates that change the 20 uniformity of the material provide uneven cuts which makes stacking of pales uneven and potentially unstable with lower parking efficiency. It will also be noted that the cuts provide a continuous outward curve. Also, the left point has less strength as the leverage between the point and the base of the cut is long enough so that leverage can provide clinking at the base of the cut under 25 force. It can also be seen that at the end of the indicator line 16 the cut is not clearly finished this typically gives rise to a point of corrosion over time. Figure 2 illustrates the present invention where the pale 20 has central point 22 and left and right points 24 and 25 created by cuts 26. These cuts 26 have an inwardly curved portion of the elongate cut 27, the cut being at the apex 28 30 of the W section of the pale. As can be seen the left and right points 24, 25 or less blade and there is less potential leverage to distort the points in use and the cuts are identical giving improve stacking and consistent strength. In this 07 02 24 particular figure the central point 22 is given a rounded end and this is consistent with the lesson splayed points 24, 25 enabled by the inward curve 27 of elongate 26 where the overall form for deterrence is maintained but the ultimate injury likely to be conveyed to a person climbing over is less dramatic. 5 The pale therefore provides the deterrent effect but without the potential for extreme injury, which may be advantageous in most domestic / commercial settings. Figure 3 illustrates a cross section of a W-cross-section pale relevant to the present invention and consistent with figure 2 the position of the elongate cuts io 36 at the centre of the apex 34 is an optimal cutting position particularly in combination with outer protrusion 33 PO which provides additional rigidity along with a Dutch bend 38 for the outer points 24, 25, these two features being and / or features in combination with the present invention. Figure 4 illustrates a, first, punch suitable for creating the elongate cut with 15 inward curve of the present invention. The illustration is a side view, in operation the pale is fed from the left, along the elongate length of the pale into the punch. The punch then closes with upper die punch 42 moving onto lower die punch 44 such that cutter 48 impinges upon the pale at a first forward point of the blade. As the dies approach one another then the formers 20   52 and 50 engage with the pale and crimp the cuts to provide the inward curve and in doing so restrain the pale from being pushed forward due to the slanted nature of knife 48. This provides a means of securing the pale without having to significantly clamp on either side of the punch. The dies approach to within the thickness of the pale and in doing so material is pressed into well 48. 25 Optional forward trim cutter 54 of the punch enables material forward of the punch to be separated. This is not necessary when an end of a-pre-cut pale is inserted. The preferred feed direction is removal of a section pressed out into well 46 and thus a pale, such is formed in a continuous production line with a strip of steel still being fed left to right. so As Figure 4 is illustrative, then it will be appreciated that the cutter 48 need not be sufficiently large that it is required to be accommodated in cavity 46. The larger knife and cavity arrangement is particularly useful for the first form of the punch where a section of material can be punched out and be discharged through the open base of cavity 46. However, cutter 48, such as illustrated in 35 figure 5 need not do more than approach the lower die punch 44 so as to cut the pale and from the elongate cut alone. 07 02 24 This punch both forms the centre point, and hence the overall end V shape (not the cross-sectional V) by cutting the pale at its end and also forming the inward bend with the elongate cut. In a, preferred, second alternative form the punch has no cutting action to 5 form the point of the pale and forms the inward curve with the elongate cut to a pre-cut point on the pale. In a, third, still alternative form the punch forms the inward curve on a pre-cut, end point and elongate cut pale (akin to that shown in Figure 1, the punch), as illustrated in Figure 6 post-forming the inward curve. This required a separate io operation from the first described punch that forms the point, forms the elongate cut and forms the shoulder all in one operation. However, that can be difficult to set up. The second described punch requires a pale with a pre-cut (timed) pale length with end v-point and forms the elongate cut and the inward curve simultaneously. This is tolerant of positioning the pale end in the 15 punch, particularly when the cutter cuts from the pale end inward (as Figure 5). It should be appreciated that the punches are shown laterally, i.e., so that the elongate pale will be fed in, such as from the left into the punch. A diagram of the punch perpendicular, i.e., in the direction of the length of the pale is not 20 shown as this is a complex shape to accommodate the V or W cross-section of the pale as well as the upper and lower former 50, 52. This is described since it should not be understood that the gutter 48, for example, impinges upon lower former 52 since these are in different planes (going into the page so to speak). I will, in this respect the lower die of the punch 44 preferably comprises 25 (not shown) protrusions to locate under the apex 34 of the profile 30 so as to stop the life crumpling / squashing the W cross-section (or equivalent V crosssection) significantly a preferred form of this is an elongate member with a rounded end rather than a member fitting entirely into the complex crosssection, such as shown in figure 3 of the pale. This is a preferred and so unexpected form since the rigidity of the pale having features such as 33 PO and 33 PI give sufficient rigidity to the sides, wings of the pale that crumpling of the apex does not occur, specifically not when a punch approach speed in the range 0.25m / s and higher is used. In summary, the present invention provides an improved endpoint for a pale 35 for a palisade fence, the endpoint having diverging points with an inward inflection to the curve of the elongate cut forming the points so is to provide additional strength and more consistent manufacture such as assists in providing identical formed pales for easier and unreliable stacking such as important in distributing product as a kit of parts prior to assembly. 07 02 24

Claims

07 02 24Claims,1. A palisade pale (20) comprising an elongate sheet of steel formed into a W or V cross-section, the pale comprising: an elongate cut (26) at one end to provide divergent end points wherein; the elongate cut (26) comprises an inwardly curved portion (27) adjacent to the base (26B) of the elongate cut, wherein the inwardly curved portion (27) forms an indentation along a portion of the base edges of the elongate cut (26) being where the cut finishes.

2. The palisade pale of claim 1 wherein the pale cross-section is a W crosssection.

3. The palisade pale of claim 1 wherein the pale cross-section is a V crosssection.

4. The palisade pale of any preceding claim wherein the outer elongate edges of the pale formed with a Dutch bend (fold back) in the material.

5. The palisade pale of any preceding claim wherein the wings of the pale have a deformation from planarity.

6. The palisade pale of any preceding claim formed from mild steel by cold rolling.

7. The present invention also provides a method of forming a palisade pale comprising providing an elongate sheet of metal formed into a W or V cross-section, the elongate sheet being cut at one end to provide diverging end points, the cut being made so as to provide an inwardly curved portion adjacent to the base of the elongate cut, comprising an indentation along the base portion of the cut being where the cut finishes.

8. A method of claim 7 wherein the method further comprises creating the elongate cut in the pre-formed w or V cross-section pale using a punch, the punch comprising a knife and curved shoulder portion to form the inwardly curved portion of the elongate cut of the pale.

9. The method of claim 8 wherein the wherein the inwardly curved portion is formed by the curved shoulder being adjacent to the base of the elongate cut.

10. The method of claim 8 or claim 9 wherein the knife is inclined.

11. The method of claim 10 wherein the inclined knife is configured to first contact that pale a point remote from the end of the pale to form the base of the elongate cut, the cut terminating at the end of the pale.

12. The method of claim 10 wherein the inclined knife is configured to first contact that pale at the end of the pale to form the base of the elongate cut, the cut terminating at a point remote from the end of the pale.

13. The method of any of claims 7 to 12 were in the pale is of W-cross-section.

14. The method of any of claims 7 to 12 were in the pale is of V-cross-section.

15. A kit of parts for preparing a section of palisade fence, the kit comprising pales as described in any of claims 1 to 6, rails and posts for forming a palisade fence.

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