Palisade fencing pales

Abstract

A method and apparatus for manufacturing palisade fencing pales 4 from strip metal 3 includes the steps of: (i) feeding the strip metal through a series of roller-pairs (S1, S2, S3) for cold rolling t

Description

DESCRIPTION PALISADE FENCING PALES Field of the Invention The present invention relates to the manufacturer of palisade fencing pales. Background of the Invention Palisade fences typical comprise a plurality of posts secured into the ground, horizontal rails secured to the posts and vertical pales secured to the horizontal rails. Palisade fencing pales are typically formed from strip metal and may have any number of cross-sectional profiles though, most commonly V-section, D-section and W-section profiles which are achieved by cold rolling strip metal. An objection of the present invention is to provide alternative / improved methods and apparatus for manufacturing palisade fencing pales. Summary of the Present Invention (DB} In accordance with the present invention, there is provided a method of manufacturing palisade fencing pales from strip metal and corresponding apparatus as claimed in the accompanying claims. More specifically, the method comprises the steps of (i) feeding the strip metal through a series of roller-pairs to form a profile in the strip metal being that profile desired of the fencing pales; and (ii) cutting the profiled strip metal into individual fencing pales, wherein the series of roller-pairs includes at least one first stage roller-pair having axes parallel to the plane of the strip metal being rolled and at least one second stage roller-pair having axes perpendicular to the plane of the strip metal being rolled whereby the first stage roller-pair(s) bends an edge of the strip metal up to 90° from the plane of the strip metal and the second stage roller- pair(s) further bend that edge of the strip metal over on itself, beyond 90° from the plane of the strip metal. The series of roller-pairs may further include at least one third stage roller- pair having axes parallel to the plane of the strip metal being rolled whereby the third stage roller-pair(s) compress that bent-over edge of the strip metal. Brief Description of Drawings The present invention will now be described, by way of example only, with reference to the following figures in which: Figure 1 is a schematic diagram of apparatus for manufacturing palisade fencing pales from strip metal; Figures 2 and 3 are derivatives of photos showing a sequence of roller-pairs for cold rolling the strip metal; Figure 4 is a table illustrating the stages of forming a bent-over edge (a ‘Dutch bend”) of the strip metal with particular roller-pairs; Figure 5 is a cross-section of the W-type palisade fencing pales formed by cold rolling with the roller pairs of figs. 2 and 3. Figure 6 is a schematic diagram illustrating the stamping / shearing of the strip metal to form the ends of the palisade fencing pales; Figures 7 and 8 are derivatives of photos showing the moveable press of fig. 1; Figure 9 is a schematic diagram illustrating the apparatus for parallel arranging of the pales of fig. 9; and Figure 10 is a schematic diagram illustrating the parallel arranging of the pales; Figures 11 and 12 are derivatives of photos showing the parallel arranging mechanism of fig. 9; and Figure 13 is a cross-section of the palisade fencing pales formed by cold rolling with the roller pairs of figs. 2 and 3. Referring to figure 1 which is a schematic diagram of the manufacture of palisade fencing pales from strip metal, a rotatably mounted coil 2 of strip metal 3 is shown as feeding the strip metal into a series of roller-pairs for cold rolling to form the desired cross-sectional profile for the fencing pales. The roller-pairs designated stage 1 (S1), stage 2 (S2) and stage 3 (S3) roller-pairs are used to form, amongst other profile features, a bent-over edge (known as ‘a Dutch bend’). Figs. 2 and 3 are derivatives of photos showing roller-pairs with fig. 2 showing stage 1 roller-pairs 21, 21" which have axes parallel to the plane of the strip metal being rolled and fig. 3 showing the stage 2 roller-pair 30, 31’ which have axes perpendicular to the plane of the strip metal being rolled. Fig. 4 is a table illustrating the stages of forming a bent-over edge of the strip metal with particular roller-pairs for both edge profiles which are initially substantially flat (in column ‘Edge Profile 1") and also angled (in column ‘Edge Profile 2’). As shown in the ‘Stage 1’ rows, stage 1 roller-pairs deform the edge of the metal strip so that its extremity (for both Edge Profiles 1 and 2) becomes substantially vertical. Subsequently, a stage 2 roller-pair (having axes perpendicular to the plane of the strip metal and the axes of stage 1 roller-pairs) causes the substantially vertical edge output from stage 1 roller-pairs for both Edge Profiles 1 and 2 to bend back on itself, i.e. significantly beyond 90° from the plane of the original strip metal (e.g. 1600 or 170°) which is beyond the capability of stage 1 roller-pairs. Lastly, a stage 3 roller-pair (having axes parallel to the plane of the strip metal being rolled and perpendicular to the axes of the stage 2 roller-pair) compress the bent-over edge of the strip metal. Ideally, the compression is such that the thickness of the bent-over edge adjacent the extremity of the original edge of the strip metal is less than that of the new bent-over edge. Many permutations to the above stage 1, 2 and 3 arrangement are contemplated including in relation to the number of roller-pairs used in each stage. Also, stage 1, 2 and 3 roller-pairs whilst primarily responsible for the Dutch bend can also to used form features of the desired pale profile which are unrelated to the edge of the strip metal. For example, those other features shown in figure 5 which is a cross-section of the presently formed W-type palisade fencing pales illustrating Dutch bends on both edges. Referring back to figure 1, the last of the roller-pairs for cold rolling to form the desired cross- sectional profile for the fencing pales feeds the metal strip 3 into a moveable press 5 which is responsible for stamping / shearing of the strip metal to form the ends of the palisade fencing pales and certain other features. Specifically, referring to fig. 6, the press is used to cut / shear out a cut-out section 60 from the strip 3 which has a flat end 63 which is common with the bottom of one pale 4 and a pointed end 64 which is common with the pointed end of the adjacent pale 4’ of the strip 3. At the same time, i.e., in a single action with the cutting / shearing out of the cut-out section 60, two holes 61, 61’ are punched and indentations / embossments 65, 65 are formed. The apertures serve as means for securing the pales to corresponding fencing rails and the indentations / embossments 65, 65’ adjacent the apertures 61, 61’ assist in securing fasteners used with the adjacent apertures 61, 61’. The press is moveable in that is configured to both move in parallel with the continuous feed of strip metal 3 when pressing the strip metal and to move back to a previous position when not pressing the strip metal 3. This ensures optimally pressing function (e.g., clean cuts / shearing, accurate punching / pressing and the like) because relative movement between the pressing elements and the continuously fed metal strip is avoided (or at the very least minimised) whilst maintaining a continuous feed of strip metal and thus continuous output of fencing pales. As shown in fig. 7, the press is composed of 3 pressing elements 71, 71’, 72 which are each supported on a common moving platform 70. Thus, the 3 pressing elements 71, 71’, 72 move in unison on the common platform. Pressing elements 71, 71’ punch the apertures 61, 62 and form the adjacent indentations / embossments 65, 65 in the pales. Central pressing element 72, 70’ is used to cut / shear out the cut-out section 60. For the purpose of manufacturing the specific pales described, each punching element operates symultaneously. However, it is possible that only individual pressing elements and / or specific combinations of pressing elements could be operative to form various permutations of pale design. Thus, the pressing function of each element is ideally individually controlled. Also, to minimise the moving weight of the press, some or all of the pressing elements 71, 71’, 72 and the underlying platform 70 could be made of Aluminium. Referring back to figure 1, a continuous feed of individual fencing pales is output from moveable press 5 along an axis and moved off-axis by apparatus 8 for parallel arranging of the pales whereafter a finishing process is applied to parallel pales. More specifically, referring to fig. 9, means 90 both provides a continuous feed of individual fencing pales along a first axis from the moveable press and orientated to be elongate in the direction of the first axis, and accelerates those the pales along that axis. For example, a roller-pair used to both receive the end of the metal strip emerging from the moveable press 5 prior to pressing and remove newly formed individual fencing pales from the moveable press 5 could also be used to accelerating the pales. Figure 10 is a schematic diagram illustrating the parallel arranging of the pales over time epochs t=0 to t=n. Specifically, successive pales (1000, 1001 ...) are accelerated along the feed axis (indicated by the arrow), halted and then moved perpendicularly, off-axis. The acceleration and halting must be done sufficiently quickly to ensure that each pale has enough time to be moved off axis before being caught up by the next pale (i.e. that following it out of the moveable press). Once perpendicularly arranged, a finishing process to create a trident shape can be applied, including applied to multiple pales at the same time (2x illustrated in fig. 10). An advantage of this arrangement is that if the finishing process takes longer than the pressing of the moveable press, arranging and processing multiple pales in parallel means that the longer finishing process can still be done without having to pause the feed of pales to avoid a backing up of pales for the finishing processing. Referring to figs. 11 and 12, means for halting successive accelerated fencing pales along the first axis includes a flexible barrier 1101 to first slow down the accelerated pales and, thereafter, an end stop and alignment means 1104 to halt the pales and guide the pales on to a chain conveyor 91. In particular, a series of rollers aligned with the first axis receives the halted pales and the rollers have an adjustable height so as to be able to lower the halted pales on to interlaced chains of the the chain conveyor 91. The chain conveyor has attached to the chains collecting members 1103 which are configured to collect and align the halted pales, thereby moving the collected pales off-axis. In the above arrangement, the orientation of the fencing pales is maintained during acceleration, halting and moving off axis. The collecting members are consistently spaced so as to uniformly distribute the collected pales on the chain conveyor. Furthermore, clamping means can be used to clamp multiple pales on the chain conveyor simultaneously in order to subject those clamped multiple pales to a simultaneous finishing activity on the chain conveyor. For example, as shown in fig. 12 and 13, the clamp comprises restraining members 1105, 1105’ that have the same profile as the pales which hold the pales securely when clamp 7 is used to apply the trident shape to the pales. Other embodiments implementing the claimed invention will suggest themselves to persons skilled in the art.

Claims

Claims 1. A method of manufacturing palisade fencing pales (4) from strip metal (3) comprising the steps of: (i) feeding the strip metal (3) through a series of roller-pairs (S1, S2, S3) to form a profile in the strip metal being that profile desired of the fencing pales; and (ii) cutting the profiled strip metal (3) into individual fencing pales (4); wherein the series of roller-pairs (S1, S2, S3) includes at least one first stage roller- pair (S1) having axes parallel to the plane of the strip metal being rolled and at least one second stage roller-pair (S2) having axes perpendicular to the plane of the strip metal being rolled whereby the first stage roller-pair(s) (S1) bends an edge of the strip metal up to 90° from the plane of the strip metal and the second stage roller-pair(s) (S2) further bend that edge of the strip metal over on itself, beyond 90° from the plane of the strip metal.

2. A method according to any preceding claim wherein at least one of the first (S1) or second (S2) stage roller-pairs form aspects of the desired profile unrelated to the edge of the strip metal.

3. A method according to claim 1 or claim 2 wherein the series of roller-pairs further includes at least one third stage roller-pair (S3) having axes parallel to the plane of the strip metal (3) being rolled whereby the third stage roller-pair(s) compress that bent-over edge of the strip metal. 4, A method according to claim 2 wherein the third stage roller-pair(s) compress that bent-over edge of the strip metal (3) such that the thickness of bent-over edge adjacent the extremity of the original edge of the strip metal is less than that of the new bent-over edge.

5. A method according to claim 3 or claim 4 wherein at least one of the third stage roller- pair(s) (S3) form aspects of the desired profile unrelated to the edge of the strip metal.

6. A method according to any preceding claim wherein the second stage roller-pair(s) (S2) further bend that edge of the strip metal over on itself, beyond 160° from the plane of the strip metal.

7. A method according to claim 6 wherein the second stage roller-pair(s) further bend that edge of the strip metal over on itself, beyond 170° from the plane of the strip metal.

8. A method according to any preceding claim wherein a bent-over edge is formed on both edges of the strip metal. S. Apparatus (1) for manufacturing palisade fencing pales (4) from strip metal (3) comprising a series of roller-pairs (S1, S2, S3) for cold rolling the strip metal including at least one first stage roller-pair (S1) having axes parallel to the plane of the strip metal (3) being rolled and at least one second stage roller-pair (S2) having axes perpendicular to the plane of the strip metal (3) being rolled wherein the first stage roller-pair(s) (S1) is configured to bend an edge of the strip metal up to 90° from the plane of the strip metal and the second stage roller-pair(s) (S2) is configured to further bend that edge of the strip metal over on itself, beyond 90° from the plane of the strip metal.

10. Apparatus (1) according to claim 9 wherein at least one of the first (S1) or second (S52) stage roller-pairs is configured to form aspects of a desired profile unrelated to the edge of the strip metal (3).

11. Apparatus (1) according to claim 9 or claim 10 wherein the series of roller-pairs (S1, S2, S3) further includes at least one third stage roller-pair (S3) having axes parallel to the plane of the strip metal being rolled whereby the third stage roller-pair(s) (S3) compress that bent-over edge of the strip metal.

12. Apparatus (1) according to claim 11 wherein the third stage roller-pair(s) (S3) is configured to compress that bent-over edge of the strip metal such that the thickness of bent- over edge adjacent the extremity of the original edge of the strip metal (3) is less than that of the new bent-over edge.

13. Apparatus (1) according to claim 11 or claim 12 wherein at least one of the third stage roller-pair(s) (S3) is configured to form aspects of a desired profile unrelated to the edge of the strip metal.

14. Apparatus (1) according to any of claims 9 to 13 wherein the second stage roller- pair(s) is configured to further bend that edge of the strip metal (S3) over on itself, beyond 1600 from the plane of the strip metal.

15. Apparatus (1) according to claims 14 wherein the second stage roller-pair(s) is configured to further bend that edge of the strip metal (S3) over on itself, beyond 170° from the plane of the strip metal.

16. Apparatus (1) according to any of claims 9 to 15 wherein a bent-over edge is formed on both edges of the strip metal (S3).

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