Patent Application
20150144855
1. Field of the Invention
This invention relates to fence tensioners especially designed for use with flexible polymer fence rails.
2. Background of the Invention
Over the past several years, composite metal and plastic fence systems have become increasingly accepted for the confinement of livestock, thoroughbred horses and the like. Typically, the fence rails are comprised of at least two wires or other high strength fibers encased in a polymer such as vinyl or other suitable plastic web. Depending on the width of the fence rail, two wires may extend along the opposite edges of the slat or, for wider slats, a third or even fourth wire may be added intermediate the edge wires. To maximize the effectiveness of the flexible fence rails, tensioning devices must be utilized to insure that the individual rails do not sag between posts. Fence tensioners have long been used to tighten individual strands in wire fence systems. The forces that need to be applied to the fence systems are such that the fence tensioners are typically constructed of metal, which is often at least partially electrically conductive. Examples of fence tensioners can be found in U.S. Pat. Nos. 6,431,487; 6,648,305; 6,848,678; and 7,475,869.
It is known to include electrically conductive wires in fence constructions for the confinement of livestock. Such systems generally include one or more electrically conductive wires. It is also known to utilize an electrically conductive wire in combination with a more visible horizontal structural element to enhance the likelihood that the animal, when shocked, will shy away from the fence. A particularly useful and more visible horizontal structural element is known to have a plurality of vertically spaced, high tensile-strength wires joined by intervening plastic webs. Examples of electrically conductive fence wires with high visibility plastic webbing can be found in U.S. Pat. Nos. 4,755,633; 5,203,541; and 6,834,846. Commonly employed fence tensioners are sometimes not electrically isolated from the conductive portion of the fence rail, thus contributing to a shorting or ground fault that can cause some portion of an electrical fence to become ineffective or inoperative.
There remains a need for a fence tensioner that will contribute to the electrical isolation of the charge carrying wires of a fence rail.
An insulated fence tensioner for use with a flexible polymer fence rail having at least one electrically conductive member can include a metal barrel including a slot for receiving an end of the fence rail. An electrically non-conductive tubular liner can be situated within the metal barrel. The tubular liner can include two edges defining a slot that can be aligned with the metal barrel slot. An electrically non-conductive sleeve can surround the metal barrel. The sleeve can include a pair of folded edges that can be positioned to penetrate the metal barrel slot and overlap the liner edges. Alternatively, the liner can include a pair of folded edges that can be positioned to penetrate the metal barrel slot and overlap the sleeve edges.
In one embodiment, the insulated fence tensioner can also include a first flange coupled to a first end of the metal barrel and a second flange coupled to a second end of the metal barrel. One of the first and second flanges can be formed of an electrically non-conductive material. One of the first and second flanges can be coupled to an end of the metal barrel to retain the tubular liner and sleeve at desired positions relative to the sleeve. The electrically non-conductive flange can include an arcuate slot dimensioned to receive one end of the metal barrel.
In one embodiment, the insulated fence tensioner can also include a bracket having a space pair of parallel plates, each plate including an opening adapted to receive one end of the metal barrel. A flange having a spaced plurality of projections can also be coupled to an end of the metal barrel, and a pawl can be pivotally mounted to the bracket so that an end of the pawl interacts with the spaced plurality of projections to selectively prevent rotation of the barrel relative to the bracket.
One feature of the insulated fence tensioner is the presence of a liner and sleeve, both made of electrically non-conductive materials, at least one of the liner and sleeve having folded edges that overlap the corresponding edges of the other to define a slot to receive a flexible polymer fence rail having at least one electrically conductive member. This feature inhibits any electrical shorting or grounding of the electrically conductive member by preventing contact with the metal barrel of the fence tensioner.
Another feature of the insulated fence tensioner is the presence of an electrically non-conductive flange positioned between the electrically conductive member of the flexible polymer fence rail and the metal mounting bracket of the fence tensioner. This feature inhibits any electrical shorting or grounding of the electrically conductive member by preventing contact with the metal plates holding the metal barrel of the fence tensioner.
The above, as well as other features and advantages, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings.
With reference to all the drawings, the same reference numerals are generally used to identify like components.
An electrically non-conductive tubular liner 28 can be situated to be received within the metal barrel 12. The tubular liner 28 can have an outside cylindrical surface 30 dimensioned to be received contiguously to the inside surface 22 of the barrel 12. The liner 28 can have a length Ll, which is slightly shorter than the length Lb of the barrel 12. The liner 28 can include two edges 32 defining a slot 34 that can be aligned with the metal barrel slot 24 when the liner 28 is inserted inside the barrel 12.
An electrically non-conductive sleeve 36 can have an inside cylindrical surface 38 dimensioned to be received contiguously over the outside surface 18 of the barrel 12. The sleeve 36 can have a length Ls, which is slightly shorter than the length Lb of the barrel 12. The sleeve 36 can include two edges 40 defining a longitudinal slot 42. The edges 40 are shown in
A first flange 46 is provided that can be coupled to the first end 14 of the barrel 12. The first flange 46 can include a pair of openings 48 dimensioned to receive the two arcuate ends 50 of the barrel first end 14. The first flange 46 can also have an outside edge 52 defined by a spaced plurality of projections 54, which can interact with a pawl as discussed later in conjunction with
A second flange 58, shown in
The fence tensioner 10 can be assembled by inserting the electrically non-conductive tubular liner 28 inside the barrel 12 so that the slot 34 of the tubular liner 28 is aligned with the slot 24 of the barrel 12. The electrically non-conductive sleeve 36 and the first flange 46 are then positioned between the spaced parallel plates 76, 78 of the mounting bracket 74. The combined barrel 12 and liner 28 are then inserted through the opening in the upper parallel plate 76 so that the edges of slots 24 and 34 straddle the web 66 of the second flange 58. The combined barrel 12 and liner 28 are then pushed into engagement with the electrically non-conductive sleeve 36 so that the folded edges 44 penetrate the slots 24 and 34, and overlap the edges 32 of liner 28. The second flange 58 is thus captured between an upper end of the sleeve 36 and the upper parallel plate 76. The first end 14 of the barrel 12 is proceeds through the opening in the lower parallel plate 78, and the first flange 46 is secured to the barrel 12 by a suitable keeper 56 inserted through apertures 25 adjacent the barrel first end 14, as shown in
Once the fence tensioner 10 assembled and secured to a fence post 84, an end 92 of a flexible polymer fence rail 94 having at least one electrically conductive member 96 can be inserted into the slot 42 as shown in
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described.
