Abstract:
An electric fence insulator is formed as a flexible band of material with an opening along a lateral periphery. The band is flexed to position around the perimeter of a fence post along a length of the fence post as determined by the length of the insulator. The insulator provides electrical insulation between an electrically energized fence wire and a point of contact of the wire with a grounded fence post. The insulator includes a fastener at the opening to close to a secure position using a simple clipping motion after the insulating band is positioned on the fence post at a selected height. The insulator forms a minimal lever arm between the fence post and the energized wire. The insulator may be retrofitted to existing installations with fence wire already installed without a need to access the fence post from the top to the section requiring electrical insulation.

Description:
PRIORITY CLAIM 
       [0001]    This application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/801,655 titled “T-Post Insulator Apparatus and Methods” filed on Mar. 15, 2013 and incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments described herein relate to fencing apparatus and methods, including electric fencing insulators and methods of manufacture thereof. 
       BACKGROUND INFORMATION 
       [0003]    Fencing materials and methods have developed over hundreds and thousands of years and continue to evolve. Fencing is used to contain livestock, to maintain a separation between species, to exclude livestock and other animals from crops, etc. Fence posts and fencing material between posts may be constructed of a variety of materials including wood, steel, composites, and others. A combination often-used in modern farm and ranching operations is steel fence posts supporting various types and numbers of strands of wire strung between posts. Straight or barbed wire may be used, for example. Barbed wire may deter animal crossing as it is sharp and may be painful for an animal attempting to cross a barbed-wire fence. Another technique that may be effective using a small number of strands is electric fencing. One or more electrically conductive strands are energized at a high voltage but are current-limited to create a strong electric shock without harming an animal attempting to cross. One complicating factor with electric fencing is the need to electrically insulate each energized strand of wire and any conductive retaining wires used to fasten the energized strand at each fence post to prevent current leakage to ground through the fence post. 
         [0004]    The steel t-post is a fence post designed for wire fencing.  FIG. 1  is a prior-art diagram of an example section  100  of a fencing t-post. Generally speaking, the t-post takes its name from its cross-sectional shape. A flat vertical member  110  orthogonally abuts a cross member  120  approximately halfway across the width of the cross member  120  at a junction  130 . The junction  130  runs the length  140  of the section oft-post  100 . 
         [0005]    Some t-post designs may also have a series of nubs (e.g., the nub  150 ) protruding from the cross member  120  on the side of the cross member  120  opposite the junction  130  of the vertical member  110  and the cross member  120 . Some t-posts may be designed with extensions  120 A and  120 B of the cross member  120  extending from the flat vertical member  110  at an angle other than 90 degrees. Other t-posts may be designed with the extensions  120 A and  120 B curved slightly toward the nubs  150 , forming a concave area populated by the nubs  150  along the length of the t-post. Each of several fencing wires is generally positioned at the bottom of an appropriate nub. The fencing wire is fastened at that position along the length  140  using a separate retaining wire wrapped around the fence wire and the edges of the vertical member  110  and the two edges of the cross member  120 . The nubs in conjunction with the retaining wire thus alleviate vertical slippage of the fencing wire along the length of the t-post. 
         [0006]    In some cases, t-posts are used to implement electric fences. In that case, an insulator is required to be fitted to each section oft-post at points touched by an electric fence wire to be energized and/or by a conductive retaining wire wrapped around the fencing wire and the fence post. Insulators may be fabricated from various electrically insulating materials including glass and plastic. Plastic insulators are known which snap around the two edges of the extensions  120 A and  120 B of the cross member  120  and extend outward from the wire surface side  170  of the t-post  100 . Such insulators thus form a lever arm outward from the t-post surface  170 . Livestock may come into contact with and dislodge such “extension type” insulators from the t-post due to the lever arm effect. 
         [0007]    “Sleeve” type insulators are also known. Such insulators slide down from the top of the fence post during installation and prior to fastening the fencing wires to the fence post. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a prior-art diagram of an example section of a fencing t-post. 
           [0009]      FIG. 2  is a cross-sectional diagram of a fence post (e.g., a t-post) shielded by an electrical insulator apparatus according to various example embodiments and shapes conforming to various fence post cross-sectional shapes. 
           [0010]      FIG. 3  is a layout of an example fence post insulator fabrication sheet capable of extrusion molding/shaping prior to forming according to various example embodiments and methods. 
           [0011]      FIG. 4  is a cross-sectional diagram of a fence post insulator apparatus according to various example embodiments and shapes conforming to various fence post cross-sectional shapes. 
           [0012]      FIG. 5  is a perspective diagram a fence post insulator apparatus according to various example embodiments and shapes conforming to various fence post cross-sectional shapes. 
         SUMMARY OF THE INVENTION 
         [0013]    Apparatus and methods described herein provide electrical insulation between an electrically energized fencing wire and a point of contact of the wire with a grounded fence post. Insulators disclosed herein form a band of electrically insulating material with a lateral opening to position around a periphery of the fence post and along a length of the fence post as determined by the length of the insulator. Embodiments of the disclosed apparatus include a fastener at the opening. The fastener is snapped to a secure closed position using a simple clipping motion after the insulator is positioned around the fence post at a selected height along the fence post length. Embodiments of the disclosed electric fence insulator thus form a minimal lever arm between the fence post and the energized wire and are more mechanically secure than prior-art devices as a result. 
           [0014]    Additionally, disclosed embodiments of the insulator may be retrofitted to existing installations with fencing wire already installed. It may be advantageous to install a fence post insulator without the need to access the length of the fence post from the top of the post to the section requiring electrical insulation. For example, an electric fence requiring repair may simply need an insulator replaced at a wire other than the top wire. Wires and other hardware above the point of repair may prevent sliding an insulator onto the fence post from the top of the fence post. 
           [0015]    Some embodiments described herein, or portions of such embodiments, may be fabricated from a stretchable band of electrically insulating material such that, when fastened around a section of a fence post as described above, may contact only convex portions of the fence post cross section and leave a gap between the fence post and the band of insulating material along concave portions of the fence post as viewed in cross-section. 
           [0016]    Some examples described and illustrated herein refer to embodiments used with t-post types of fence posts. However, embodiments of the invention are not limited to use with t-posts. The invented insulator may be formed in any shape to conform to or be positioned around the cross-sectional shape of any fence post, whether metallic, wooden, composite, or fabricated from some other material. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 2  is a cross-sectional diagram of a fence post (e.g., the t-post  100  of  FIG. 1 ) electrically insulated by an insulator apparatus  200  according to various example embodiments and shapes conforming to various fence post cross-sectional shapes. In the case of the example t-post  100  shown in cross-section inside the insulator apparatus  200 , the insulator apparatus  200  forms a cross-shaped covering made up of sides S 1  through S 12 . In the case of a t-post type of fence post such as the t-post  100 , the cross hatch area  205  of  FIG. 2  represents t-post nubs (e.g., the nubs  150  of  FIG. 1 ) located along the insulated longitudinal section of the t-post  100  covered by the insulator apparatus  200 . 
         [0018]    However, it is noted that embodiments of the insulator apparatus  200  are each fabricated as a band of electrically insulating material to surround a section of fence post and thus to conform to the number and shapes of the sides of the fence post along a section of the fence post corresponding to the height of the insulating band. Thus, the insulator apparatus  200  may vary in shape and size according to the shape and size of the fence post. In the case of a round cross-sectional shaped fence post, for example, the band of the insulator apparatus  200  is formed in a rounded cross section to surround and grasp the round cross-sectional shaped fence post along a longitudinal section of the fence post. 
         [0019]    The insulator apparatus  200  may be manufactured in various lengths, the length being the drawing dimension orthogonal to the drawing sheet surface and continuing downward from the drawing sheet surface. The insulator apparatus  200  is constructed as a band of electrically insulating material to position around a longitudinal section of a fence post such as to electrically insulate one or more conductive fencing wires  208  positioned perpendicular to the longitudinal section of the fence post to be insulated from the fencing wire(s)  208 . 
         [0020]    The band of the insulator apparatus  200  is fabricated from a plastic, composite, or other mechanically conformal and electrically insulating material of sufficient insulating strength to substantially prevent current flow from the charged fencing wire  208  through the fence post and to ground. The insulator apparatus  200  includes a lateral opening  210  along its length so that the flexible band of the insulator apparatus  200  may be bent open to install around the fence post prior to fastening as described below. Some embodiments of the insulator apparatus  200  may be hinged with one or of more hinges  213  positioned at one or more positions along the periphery  214  of the insulating band of the insulator apparatus  200 . An axis of such hinge lies perpendicular to the periphery  214  of the band and facilitates installation around a fence post of large cross-sectional area to avoid excessively deforming or breaking the insulator apparatus  200  during installation. 
         [0021]    Embodiments of the insulator apparatus  200  include one or more fastener(s)  215  to secure the insulator apparatus  200  at a selected longitudinal position along the length of the fence post. The fastener  215  may be of various types, including a hooked clip fabricated along one vertical edge of the insulator apparatus  200  to slide into a recess or around a raised edge fabricated at a matching position along the opposite vertical edge of the insulator apparatus  200 . In some embodiments, the fastener  215  may include matching convex-shaped hooks fabricated along matching vertical edges of the insulating band forming the apparatus  200  as shown in  FIG. 4  and as described below. The fastener  215  may alternatively include strap extensions of the insulator apparatus  200  and/or straps fabricated onto the insulator apparatus  200  at matching positions along each vertical edge of the insulator apparatus  200 . Such straps may be fastened together to secure the insulator apparatus  200  to the fence post using buckles, hook and loop material, or any other strap fastener mechanism known in the art of strap fasteners. 
         [0022]      FIG. 3  is a layout of an example fence post insulator fabrication sheet  300  prior to forming by extrusion molding/forming according to various example embodiments and methods. Width segments of the insulator sheet  300  are labeled S 1 -S 12  and correspond to the cross-sectional sides of the insulator apparatus  200  as illustrated in  FIG. 2 . Vertical crease lines (e.g., crease lines  305  and  307  associated with side S 6 ) parallel to a longitudinal axis of the insulator apparatus  200  indicate bends between each of the sides S 1 -S 12  created during extrusion/forming in a direction of the crease lines. In some embodiments, said bends may be fabricated into the insulator sheet  300  during extrusion/forming or at a prior time by perforating the insulator sheet  300  along the crease lines, removing plastic material to a selected depth from one side or the other of the insulator sheet  300  along the crease lines, etc. 
         [0023]    Embodiments of the insulator sheet  300  may include various types of fastener devices as previously mentioned, including but not limited to clip-into-recess fasteners  310 A/ 315 A and  310 B/ 315 B as shown. Although two fasteners are shown in the example insulator sheet  300 , various embodiments of the insulator sheet  300  may include an appropriate number of fasteners as determined by the longitudinal length  320  of the insulator sheet  300  and the strength of each fastener as designed to appropriately secure the insulator apparatus  200  to the fence post. 
         [0024]    In the case of embodiments of an insulator apparatus for use with a t-post, upon installation the insulator apparatus will cover, insulate and make unavailable nubs  150  formed on the t-post as previously described. In replacement, nubs (e.g. the nub  325 ) may be formed at a surface of the insulator sheet  300 . Said nubs  325  may be formed during the extrusion process or during a post process operation. The nubs  320  may be formed from the same plastic as the insulator apparatus  200  or may be formed from a different material and later affixed to or molded into the insulator sheet  300 . The nubs  325  provide a surface against which a fencing wire may rest or be pulled tight, as was described for the nubs  150  associated with the t-post  100 . 
         [0025]    The extruded t-post insulator sheet  300  is cut to the length  320  corresponding to the desired longitudinal length of the insulator apparatus  200 . Before or after cutting to length, the insulator sheet  300  flows through a forming device. The forming device makes the appropriate bends at the crease lines and stabilizes the bend angles as appropriate to the cross-sectional shape of the fence post. Stabilization may be achieved using cement, melting material along the crease lines, plastic welding, etc. 
         [0026]      FIG. 4  is a cross-sectional diagram of a fence post insulator apparatus  400  according to various example embodiments and shapes conforming to various fence post cross-sectional shapes. Some t-post designs are similar to the t-post  100  shown in  FIG. 2  but utilize a cross member  120  that is slightly concave with respect to the nubs  150 , as previously mentioned. It is noted that, unlike  FIG. 2 ,  FIG. 4  does not show a corresponding fence post cross-section except for a shaded area representing the nubs  150  of the fence post. The insulator apparatus  400  as shown in  FIG. 4  is shaped to conform to the latter concave t-post design. However, the shapes of various embodiments of the insulator apparatus  400  may differ in order to conform to the shapes of various fence posts, as previously mentioned generally regarding various embodiments of the invention. 
         [0027]    Some embodiments of the insulator apparatus  400  include hook-shaped perimeter ends  415 A and  415 B at the previously-mentioned lateral opening  210 . The hook-shaped perimeter ends  415 A and  415 B form an embodiment of the fastener  215  described with reference to  FIG. 2 . The insulator apparatus  400  is opened at the lateral opening  210  and temporarily deformed to install around a t-post or other fence post type at a desired height along the fence post. The hook-shaped perimeter ends  415 A and  415 B are then snapped together to retain the insulator apparatus  400  at the desired height along the fence post corresponding to the height above the ground of the fencing wire  208  to be energized. 
         [0028]      FIG. 5  is a perspective diagram of the fence post insulator apparatus  400  according to various example embodiments and shapes conforming to various fence post cross-sectional shapes. It is noted that a height  510  of the insulator apparatus  400  may vary according to the number of fencing wires to be insulated by a single insulator apparatus  400  and by an amount of anticipated vertical slippage of the fencing wire  208  upward and/or downward along the height  510 . Thus, for example, longer-length embodiments of the insulator apparatus  400  may be suitable for insulating multiple adjacent fencing wires. It is noted that the “length” and the “height”  510  are being referred to here synonymously as the dimension of the insulator apparatus  400  corresponding to a longitudinal dimension of a fence post section to be covered by and electrically insulated by the insulator apparatus  400 . Longer-length embodiments may also reduce the likelihood of slippage of the fencing wire and/or the retaining wire off of the insulator apparatus  400  and onto the grounded fence post. 
         [0029]    Longer-length embodiments may result in higher materials cost, however. Some embodiments of the insulator apparatus  400  may include lateral retaining slots (e.g., the lateral retaining slots  515 A and  515 B) fabricated into a portion of the thickness of the insulator apparatus  400 . The retaining slots may be fabricated at convex extension areas of the insulator apparatus  400  at positions where the fencing wire  208  and/or the above-described retaining wire (e.g., retaining wire section  520 ) are anticipated to contact the insulator apparatus  400  when the fencing wire  208  and the retaining wire are tensioned. The retaining slots may improve the trade-off between reliability of maintaining the energized wires on the electrically insulating apparatus  400  and increased materials cost resulting from a longer length dimension  510 . 
         [0030]    Various embodiments of the insulator apparatus (e.g., the embodiments  200  and  400 ) may be fabricated according to various methods, including injection molding or extrusion followed by slicing a longer extruded product into shorter sections. 
         [0031]    The apparatus of various embodiments may be useful in applications other than providing electrical insulation of fencing and/or retaining wires from grounded fence posts used in electric fence applications. Thus, various embodiments of the invention are not to be so limited. The illustrations of the insulating apparatus  200  and  400  and of the intermediate product of manufacture  300  are intended to provide a general understanding of the structure of various embodiments. They are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. The novel apparatus of various embodiments may be incorporated into various systems and methods of fencing. 
         [0032]    It is noted that activities described herein may be executed in an order other than the order described. The various activities described with respect to methods identified herein may also be executed in repetitive, serial, and/or parallel fashion. 
         [0033]    Apparatus and methods described herein surround a longitudinal section of a grounded fence post with a band-shaped insulator apparatus with a lateral opening and a fastener at the opening. The insulator apparatus electrically insulates fencing wire and/or retaining wire positioned at the longitudinal section from the grounded fence post supporting the wire. Increased durability and reliability may result from the absence of or shortened length of a lever arm between the insulator and the fence post. 
         [0034]    By way of illustration and not of limitation, the accompanying figures show specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be used and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense. The breadth of various embodiments is defined by the appended claims and the full range of equivalents to which such claims are entitled. 
         [0035]    Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit this application to any single invention or inventive concept, if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments and other embodiments not specifically described herein will be apparent to those of skill in the art upon reviewing the above description.