GB2240351A

GB2240351A - Method of and apparatus for making a wire fencing panel

Info

Publication number: GB2240351A
Application number: GB9020783A
Authority: GB
Inventors: Richard Bruce Cochrane
Original assignee: Cochrane Steel Products Pty Ltd
Current assignee: Cochrane Steel Products Pty Ltd
Priority date: 1990-01-24
Filing date: 1990-09-24
Publication date: 1991-07-31
Anticipated expiration: 2010-09-24
Also published as: GB2240351B; DE4035388A1; GB9020783D0

Abstract

A fencing panel which is made from superimposed arrays of barbed tape (50, 52) oriented so that core wires (60) in the lengths of barbed tape are brought into contact with and can be welded to one another (66). The lengths of barbed tape are assembled on a jig (28, 30, 32, 34 - Fig. 2) which is moved in steps relatively to a welding machine (14, 40) which welds the barbed tape lengths together. <IMAGE>

Description

Method of and Apparatus for Making a Fencing Panel This Invention Is

concerned with a method of and apparatus for making a panel which is used in the construction of security fencing, and with such a panel.

According to the invention a method of making a fencing panel includes'the steps of arranging a first plurality of lengths of barbed tape in a first array, arranging a second plurality of lengths of barbed tape in a second array which overlies the first array, and securing the lengths of barbed tape together at points where the lengths of barbed tape contact one another.

The two arrays of barbed tape may be positioned on a jig to ensure the correct spacing and orientation of the lengths of barbed tape relatively to one another. The jig may incorporate locating formations to assist in this 20 respect.

The lengths of barbed tape may be secured to one another in any suitable way and preferably use is made of a welding technique for this purpose.

The jig and the lengths of barbed tape on the jig may be caused to move relatively to a welding machine which acts on the lengths of barbed tape. The movement of the jig may be indexed or stepped and the welding machine may be 30 operated between successive steps of the jig. Alternatively the Jig Is stationary and the welding machine Is moved, In successive steps, along the length of the Jig.

The jig may be endless, mounted for example on an endless conveyor, so that the fencing panel can be made to any i 1 1 -2desired length. In a variation of the invention the jig is mounted to a frame and each fencing panel is made to predetermined dimensions of length and width, which may be substantially equal to the dimensions of the frame.

i Each length of barbed tape includes a core wire and a metallic strip, formed with barbs, wflich is deformed to surround the core wire partially, with the barbs projecting from opposing sides of the core wire, and the lengths of barbed tape are oriented so that the core wires of the first array are brought into contact with, and are welded to, the core wires of the second array.

The metallic strips of each array are oriented so that at least the barbs are co-planar.

The invention also provides apparatus for making a fencing panel which includes a jig, locating formations on the jig which are adapted to receive superimposed layers of barbed tape, a welding machine, and means for causing stepped movement of the jig relatively to the welding machine thereby to present points, at which the lengths of barbed tape contact one another, to the welding machine for wel ding together.

The jig may be endless and for egample include an endless conveyor and the welding machine may be located adjacent the discharge end 9f the conveyor. This permits the fencing panel U be made to any desired length.

Alternatively the jig includes a frame and the fencing panel is made to predetermined dimensions wtich are established Inter tlia by the dimensions of the frame. The jig may he attached to a conveyor which moves in steps 35 relatively to a welding machine.

1 -3The conveyor may be moved with the welding machine stationary or the welding machine may be moved with the jig stationary.

The jig my comprise a frame with a plurality of transverse members secured to it and each member may have a plurality of locating formations on it. With the jig in this form fencing panels of predetermined dimensions of length and width are made, these dimensions being determined primarily by the dimensions of the jig.

The jig may present on its upper surface locating formations which are adapted to receive lengths of barbed tape in a predetermined configuration.

The invention also provides a panel for a security fence which includes a first plurality of lengths of barbed tape arranged in a first array, and a second plurality of lengths of barbed tape arranged in a second array which overlies the first array, each length of barbed tape including a core wire and a metallic strip which partly surrounds the core wire and which is formed with barbs which project from opposing sides of the core wire, the lengths of barbed tapebeing oriented so that the core wires in the first array are brought into contact with respective core wires in the second array, and the core wires in the first array being welded to the respective core wires in the second array.

Preferably the lengths of barbed tape in each array are oriented so that the barbs are substantially co-planar.

The Invention Is further described by way of examples with reference to the accompanying drawings in wflich:

Figure 1 Is a plan view of apparatus according to the 4 invention for making a fencing panel of barbed tape, Figure 2 is a cross sectional side view of the apparatus of Figure 1, Figure 3 shows in plan portion of a panel produced with the apparatus of Figures 1 and 2, Figure 4 is a cross sectional view through the panel of Figure 3, on the line 4-4, Figure 5 is a plan view of a jig used in a variation of the invention, and Figure 6 is an enlarged perspective view of portion of the jig of Figure 5.

Figures 1 and 2 of the accompanying drawings schematically I llustrate apparatus 10 according to the invention for making a fencing panel from barbed tape. The apparatus includes an endless conveyor 12 and a welding machine 14.

The conveyor 12 includes first and second sprockets 16 and 18 which are mounted on a shaft 20 for rotation by means of a motor 22. A second pair of sprockets 24 and 26 which are also mounted on a common axle are spaced from the first sprocket pair. The sprockets are carried on a suitable supporting structure, not shown.

Endless chains 28 and 30 are respectively engaged with the sprockets 16 and 24, and 18 and 26.

A plurality of spaced transverse support members 32 are secured at regular Intervals to the outer surfaces of the two chains 28 and 30. These supports carry pairs of upstanding locating formatIons 34 to form a jfg for q j i i correctly locating lengths of barbed tape.

Positioned alongside the chains are two elongate guides 36 and 38 respectively. Each guide consists of a length of angle iron and is arranged so that it has an outer upwardly extending flange.

The welding machine 14 is a resistance welding machine and includes a plurality of spaced welding heads 38 positioned above matching plattens 40. The welding heads 38 are moved up and down in unison by means of an actuating mechanism, not shown, which may be of any known type.

A sensing device 42 is positioned alongside the conveyor and detects the passage of the successive transverse supports 32. The sensing device is interconnected to the motor 22, and to the actuating mechanism of the welding machine 14. The sensing device may be a device such as a reed or mercury switch.

In use of the apparatus of the invention a plurality of straight lengths of barbed tape 50 are laid in a first array, spaced from one another, on the transverse support members 32. Thereafter a second array of lengths of barbed tape 52 are laid over the lengths 50. The two arrays are so positioned that they intersec or overlie one another on the transverse supports and the points of contact of the overlying lengths of barbed tape are positioned between the pairs of locating formations 34. In this way a regular and symmetrical assembly of the lengths of barbed tape is achieved. The ends of the lengths of barbed tape rest on the guides 36 and 38 which thus ensure that the lengths of barbed tape are correctly laterally positioned relatively to one another.

Figures 3 and 4 show a_portion of the barbed tape lengths -652 superimposed on the lengths 50. Each length of barbed tape includes a core wire 60 and a metallic strip 62 which is formed with barbs 64. The strip is folded on to the core wire 60 so that it partly surrounds the core wire, and so the barbs 64 project from opposing sides of the core wire. This process is known and consequently is not further described herein.

The lengths of barbed tape are oriented so that the barbs 64 in each array are substantially co-planar, see Figure 4, and so that the core wires in the two arrays, visible between the shaped portions of the surrounding metallic strips 62, oppose, and can be brought into contact with, one another, at locations 66, see Figure 4. It is possible to keep the barbs co-planar by ensuring that each length of barbed tape is formed without axial twisting. This in turn is accomplished by fabricating the barbed tape on a suitable machine and then, without coiling the emerging fabricated barbed tape, cutting the barbed tape into sections of the desired length. This process, if carefully carried out, provides straight lengths of barbed tape which have no axial twist, and with co-planar barbs.

Once the lengths of barbed tape have been assembled in the manner described, and the upper surface of the conveyor 12 is substantially covered by the barbed tape, the motor 22 is turned on. The motor is under the control of the sensing device 42 which acts as an indexing mechanism. The motor drives the conveyor 12 forward by an amount which is equal to the spacing between successive transverse supports 32. The welding machine 14 is so positioned that the points of contact of the lengths of barbed tape are brought into position directly above respective plattens 40. The motor 22 Is stopped when the sensing device 42 has detected a predetermined degree of movement and the welding machine 14 Is actuated by-a signal from the i -7sensing device 42. The welding heads 38 come down to create a resistance weld between each of the contacting pairs of the lengths of barbed tape.

As has been described with reference to Figures 3 and 4 the visible portions of the core wires 60 in the two arrays of barbed tape oppose each other at locations 66. Thus, when the welding heads come down, the core wires are forced together and contact one another and so are directly resistance welded to each other at the locations 66. This technique is important for it ensures a sound weld which is far stronger than what would be the case if, for example, the core wires were welded to each other with one or two of the metallic strips 62 between the core wires.

When the heads rise a control signal is applied to the sensing device 42, from a manually actuated switch which is operated by the upwardly moving heads, and the motor is again energised to drive the conveyor 12 forward. The sensing device 42 detects the advent of the next transverse support and then stops the motor drive. The welding machine is then again actuated in the manner described. At regular intervals, depending on the length of the conveyor 12, the aforementioned process is stopped so that fresh lengths of barbed tape can be laid over one another in the criss-cross pattern shown in Figure 1, and with the orientations shown in Figures 3 and 4. The welding and indexing process is then continued.

The material leaving the welding machine Is In effect a continuous length of diamond mesh fencing made from the Inter-welded lengths of barbed tape. A receiving table, not shown, is positioned to the right of the welding machine and the emerging fencing panel is guided on to this table. The fencing panel can be cut, by any 1 -8appropriate means, into suitable lengths to facilitate handling.

In the panel the protruding barbs 64 in each array are substantially co-planar and lie in the plane of the panel This is important for aesthetic and safety reasons. If the barbs project from the plane of the panel they are more dangerous and can inadvertently cause bodily harm. On the other hand when the barbs are co-planar the security value of the panel is not diminished, and the likelihood of accidental injury is reduced.

Figures 5 and 6 show a jig 70 used in a variation of the i nvention which includes a frame 72, a number of spaced non-conductive slabs 74, and a plurality of channel members 76 which are fixed to the slots, inclined to one another. Lengths of barbed tape 78 are positioned in the channel members 76 in the manner previously described so that their respective core wires face, and are brought into contact with, one another.

The lengths of barbed tape are cut so that they do not overlap the sides of the frame 72 and thus make up a panel of substantially the same length and width as the frame 72. The wires cross one another between adjacent slots.

A number of parallel rods or wires 80 attached to the frame 72 overlie the barbed tape lengths and keep them in the channel members.

The jig 70 with the barbed tape lengths is placed on a conveyor, which may be endless, which is moved in step fashion past a welding machine in the manner described in connection with Figures 1 and 2 so that the lengths of barbed tape can be welded to one another. Alternatively the jig 70 Is kept stationary and the welding machine, 1 2 1 -gmounted to a suitable travelling mechanism, is stepped along the length of the jig and the barbed tape lengths are thereby welded to one another.

It is to be noted that with the jig of Figures 5 and 6 each panel is made to a predetermined size whereas with the approach of Figures 1 and 2 the panels are made of indeterminate length and are cut to size as required.

The apparatus of the invention makes it possible therefore to fabricate a fencing panel out of lengths of barbed tape. The fencing panels are formed in desired sizes, supported by fence posts, In a conventional way to form a security fence which is aesthically acceptable. The is fencing panels can be formed with a diamond mesh shape, as described, with a rectangular mesh configuration, or in any other configuration.

9

Claims

1. A method of making a fencing panel which includes the steps of arranging a first plurality of lengths of barbed tape in a first array, arranging a second plurality of lengths of barbed tape in a second array which overlies the first array, and securing the lengths of barbed tape together at points where the lengths of barbed tape 10 contact one another.

2. A method according to claim 1 wherein the two arrays of barbed tape are positioned on a jig to ensure the correct spacing and orientation of the lengths of barbed tape relatively to one another.

3. A method according to claim 1 or 2 wherein the lengths of barbed tape are welded to one another.

4. A method according to claim 3 wherein each length of barbed tape includes a core wire and a metallic strip, formed with barbs, which is deformed to surround the core wire partially, with the barbs projecting from opposing sides of the core wire, and the lengths of barbed tape are oriented so that the core wires of the first array are brought into contact with, and are welded to, the core wires of the second array.

5. A method according to claim 3 or 4 wherein the lengths of barbed tape are oriented so that the barbs in each array are co-planar.

6. Apparatus for making a fencing panel which includes a jig, locating formations on the jig wbich are adapted to receive superimposed layers of barbed tape, a welding machine, and means for causing stepped movement of i -lithe jig relatively to the welding machine thereby to present points, at which the lengths of barbed tape contact one another, to the welding machine for welding together.

7. Apparatus according to claim 6 wterein the jig is in the form of an endless conveyor and the welding machine is located adjacent the discharge end of the conveyor.

8. Apparatus according to claim 7 wherein the conveyor presents on its upper surface locating formations which are adapted to receive lengths of barbed tape in a predetermined configuration.

9. Apparatus according to claim 6 wflerein the jig includes a frame with a plurality of transverse members each of which has locating formations which are adapted to receive lengths of barbed tape in a predetermined configuration.

10. A panel for a security fence which includes a first plurality of lengths of barbed tape arranged in a first array, and a second plurality of lengths of barbed tape arranged in a second array which overlies the first array, each length of barbed tape including a core wire and a metallic strip which partly surrounds the core wire and which is formed with barbs wMch project from opposing sides of the core wire, the lengths of barbed tape being oriented so that the core wires in the first array are brought into contact with respective core wires in the second array.

11. A panel according to claim 10 wherein the lengths of barbed tape in each array are oriented so that the barbs are substantially co-planar.

1 -1212. A method of making a fencing panel substantially as herein described with reference to the accompanying drawings, Figures 1 to 4, or Figures 3 to 6.

I( A, 13. Apparatus for making a fencing panel substantially as herein described with reference to the accompanying drawings, Figures 1 to 4 or Figures 3 to 6.

14. A fencing panel substantially as herein described 10 with reference to the accompanying drawings.

15. A fencing panel wflich is made in accordance with the method of any one of claims 1 to 5.

I i i Published 1991 atIbe PatentOfftce. State House. 66/71 High Holbom. LDndonWCIR4TP. Furth rnay be obtained frorn Sales Branch. Unit 6. Nine Mile Point Cwnifelinf2ch. Cross Keys. Newport. NPI 7HZ. Printed by Multiol:=Ptrues lid. St Mary Cray. Kent.