ELECTRIC NETTING

Abstract: Netting (10) comprises a mesh of horizontal elements (11) and vertical elements (12) which are interconnected at their intersections by knots or plastic welds (13). The vertical elements (12) and the bottom horizontal element (14) are electrically non-conductive. The other horizontal elements (11) are divided into sets (15 and 16); each set having its free ends (17, 18) connected to respective connectors (19 and 20). The sets can be electrically independent of each other.

Description: Electric Netting This invention relates to electric netting for use as temporary and semi-permanent fencing for animal control. It has been known for at least twenty years to make a 5 flexible net which can be supported on insulated posts. The horizontal elements of the net carry bare electrically conductive wire which is often either wound around or intertwined with the plastic fibres making up the element. At their free ends the horizontal elements- or at least 10 their wires, are interconnected to respective connectors. The lowermost horizontal element is electrically insulated or is of electrically non-conductive materials. In use the electrical connector at one end is connected to a live power source and a connector on the other end is plugged to a 15 corresponding connector at the end of another fence section. If an animal touches any of the horizontal elements other than the lowermost one, an electric current will pass through its body to the ground completing the electrical circuit with the power pack which itself is earthed in the 20 ground. In this way the animal receives a shock which is a deterrent to approaching the fence. In normal climatic conditions it is extremely effective as a means of 't controlling animals and it is necessary for the lowermost ϊ horizontal element to be electrically non-conducting, 25 otherwise the fence will short circuit directly to the ground. The effectiveness of the fencing arrangement above described is dependent on the conductivity of the ground between the location of the power pack and the most distant portion of the fence. Throughout much of the year in temperate climates that conductivity is sufficient to ensure that the electric fencing is effective over a considerable distance. However, in arid climates, or in temperate climates during dry periods, the distance over which the conductivity of the ground can be effective may be seriously reduced. For such conditions a different type of fence has been developed in which the horizontal elements are connected up in two sets such that the elements are arranged in live/earth pairs. This means that the current passes from a live wire through the animal to an earth wire. In such fencing it has always been arranged that the lowermost horizontal element is electrically conductive and, being in contact with the ground and with the metallic ground spikes of the supporting fence posts, is so connected as to have an earth or negative potential. It has been found that, with mesh-type fencing in which the vertical elements are composed of flexible twines, upwards variation in ground contour between adjacent supporting posts can bring the lowermost horizontal conductive element, which is of negative potential, into contact with the second lowermost horizontal conductive element, which is of positive or live potential. This can result in a short circuit with the consequence that the fence is rendered electrically ineffective. From one aspect the invention consists in electrifiable netting comprising a plurality of generally orthogonal elements interconnected to form a mesh such that when supported on posts there are two series of elements, one generally vertical and the other generally horizontal, wherein the lowermost horizontal element and the vertical elements are electrically non-conductive and wherein the remaining horizontal elements are electrically conductive and connected to one another and to respective electrical connectors at each ' end of the length of netting so as to form two interleaved but mutually insulated sets. It will be understood that this new configuration enables the fence to be operated either with the two sets of electrically conductive horizontal elements connected respectively to the live terminal of a power supply and the earth or, alternatively, with both sets of elements connected to the live terminal of a power supply. Thus in a preferred embodiment the elements of one set alternate with the elements of the other .set and all the horizontal elements other than lowermost fall within one set or the other. The electrically conductive elements may be flexible and, may comprise a carrier of non-conductive material and, one or more bare wires. The generally vertical non- conductive elements may also be flexible. The invention includes means for electrically connecting the connectors at the respective ends of the netting. From another aspect the invention consists in an electrifiable netting comprising a plurality of electrically conductive generally parallel elements interconnected into two sets such that all the elements can be made live or one set can be made live and the other earthed. The invention further includes an electric fence including netting as defined above. The fence may include a power source and means for connecting the power source to the netting such that the elements in one set are live and the elements in the other set are earthed. Although the invention has been defined above it is to be understood that it includes any inventive combination of the features set out above or in the following description. The invention may be performed in various ways and specific embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic representation of an electric fence using the electric netting according to one aspect of the invention, and Figure 2 is a diagrammatic representation of an electric fence using the electric netting according to another aspect of the invention. In both the figures an electrically conductive net indicated at 10 comprises a mesh of horizontal elements 11 and vertical elements 12 which are interconnected at their intersections by knots or plastic welds 13. The vertical elements 12 are non-conductive as is the bottom horizontal element 14. The other horizontal elements 11 are divided into sets 15 and 16; set 16 being shown in broader lines, for illustration purposes only. The elements 11 of these sets are electrically conducting and their free ends 17 and 18 are connected to respective connectors 19 and 20. The said free ends are so insulated that the sets can be electrically independent of one another. Alternatively the ends of the wire in a set can be connected to a single insulated cable which has the connector 19 or 20 on its other end. The fence is supported and affixed to the ground by fencing posts 21 which are electrically insulating throughout that portion of their structure which remains above the lowermost horizontal member 14. In the case of semi-permanent fences the posts may be of any suitable material either self insulating or with insulators affixed. In Figure 1 the connector 19 at one end of the length of fencing 10 is connected to the live terminal 22 of the electric power source 23 which is earthed through the metal earth rod 24 of the power unit and connector 20 is also connected to the earth rod 24. The connectors are the other end of the length or fencing 10 are connected to corresponding connectors on a further length of fencing. In Figure 2 the connectors 19 and 20 at one end of the length of fencing 10 are both connected to one another by a further connector 25 which is connected to the live terminal 22 of the electric power source 23 which is earthed through the metal rod 24. The connectors at the other end of the length of fencing 10 are connected, as in Figure 1, to corresponding connectors on a further length of fencing. It will be seen that by providing this particular configuration of electrically connected horizontal elements with a non-conducting lowermost horizontal element, the Applicant has, with surprising simplicity, developed a fence which can be used in both the Figure 1 and Figure 2 arrangements, thus enabling a single fence to satisfy all markets and also permitting farmers in temperate climates with one set of fencing for use in one electrical configuration during normal conditions and another configuration during the drier parts of the year when the efficiency of current electric fencing is greatly diminished, a facility which can at present only be provided for if the user were to stock two separate sets of netting.

Claims: CLAIMS 1. Electrifiable netting comprising a plurality of generally orthogonal elements interconnected to form a mesh such that when supported on posts there are two series of elements, one generally vertical and the other generally horizontal, wherein the lowermost horizontal element and the vertical elements are electrically non-conductive and wherein at least a proportion of the remaining horizontal elements are electrically conductive and connected to one another and to respective electrical connectors at each end of the length of netting so as to form two interleaved but mutually insulated sets. 2. Netting as claimed in Claim 1, wherein the elements of one set alternate with the elements of the other set and all the horizontal elements other than the lowermost fall within one set or the other. 3. Netting as claimed in Claim 1 or Claim 2, wherein the electrically conductive elements are flexible. 4. Netting as claimed in any one of the preceding claims, wherein each electrically conductive element comprises a carrier of non-conductive material and one or more bare wires. 5. Netting as claimed in any one of the preceding claims, wherein the generally vertical non-conductive elements are also flexible. 6. Netting as claimed in any one of the preceding rι O claims, further comprising means for electrically connecting the connectors at the respective ends of the netting. 7. Electrifiable netting comprising a plurality of electrically conductive generally parallel elements inter- connected into two sets such that all the elements can be made live or one set can be made live and the other earthed. 8. Electrifiable netting substantially as hereinbefore described with reference to the accompanying drawings. 9. An electrifiable fence including netting as claimed in any one of the preceding claims. 10. A fence as claimed in Claim 9, further including a power source and means for connecting the power source to the netting such that the elements in one set are live and the elements in the other set are earthed.

Inventors: ALDEN ROY NORMAN FREDERICK, ALDEN, ROY, NORMAN, FREDERICK
Applicants: ALDEN ROY N F, ALDEN, ROY, NORMAN, FREDERICK
Application year: 1991
Main classification: H05C1
IPC codes: H05C1