Abstract:
An improved animal barrier material and an improved fastening system to simplify its knotting process are disclosed. In the preferred embodiment, a plurality of multi-stranded metallic cables are joined together using parallel overhand knots. A pair of metallic cables may be taken together to form substantially adjacent portions which then form a loop. The pair of metallic cables passes around a portion of the loop and through the loop to form a overhand know. Such a knot minimizes stress and fatigue on the netting and makes the netting nearly invisible to the naked eye at a distance of more than a few feet.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 08/710,724, filed Sep. 19, 1996, now U.S. Pat. No. 5,788,223 which in turn claims priority from Provisional U.S. Application Ser. No. 60/003,946, filed Sep. 19, 1995; and Provisional U.S. Application Ser. No. 60/003,947, filed Sep. 19, 1995; all three of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention described herein is related generally to meshed nettings, and is related more specifically to a meshed netting of metallic composition for fixed deployment as a see-through protective barrier. 
     BACKGROUND OF THE INVENTION 
     Zoos have sought improved barriers for containment of zoo animals with less visually-obtrusive means. The demand for less visible barriers has led to development of a number of different containment strategies. The ultimate goal of an invisible barrier has remained largely unfulfilled for zoo administrators and the general public. Some efforts have been made to achieve this goal by zoo designers working in concert with product manufacturers. 
     Barriers fall into one or more of the following categories: see-through fencing, including meshes of a variety of materials and descriptions, tension wire and electrified wire; barriers of transparent glass; wet and dry moats; and walls made of simulated rock. Each containment approach has advantages and is useful in certain applications, but there is still plenty of room for improvement, consequently, designers and manufacturers continue to seek new ways to satisfy the demand for better barriers. 
     Since fencing is usually cheaper than moats, windows, or walls, a major focus has been to develop stronger and less visible cable meshes. In addition, fencing may allow visitors better access and visibility to animals and exhibits. Moats and other such enclosure generally place the viewer at a great distance from the animal or exhibit. Cables made of metal offer many advantages as a fencing material, (i.e., relatively low cost, strength, flexibility, durability, availability, and the like). 
     The demand for cable netting has led to development of a number of different products. Consequentially, a number of different cable products have been introduced to the markets in recent years. Despite the variety of products now available, there is still a substantial need for improvement. 
     Cable meshes may be produced by laying out separate cables and joining them to each other in various ways. The challenge here is to join the cables at regular points of intersection in a cost-effective, aesthetic, and dependable manner. 
     One prior-art netting is comprised of 1/16&#34; or 3/32&#34; stainless steel cables which are joined at regular intervals with cylindrical metal fasteners (e.g., crimp &#34;barrels&#34; or the like) which are threaded over the cables and crimped. Such a netting forms diamond-shaped openings when stretched. Such a prior-art netting may be marketed by Kettner &amp; Associates, Inc. of Mequon, Wis. This prior-art mesh is considered quite effective for containment of mammals, such as leopards and baboons. The crimped connectors are, however, noticeably visible, and the cables are generally thicker than desirable for aviaries and other light-duty enclosures. The crimped meshes are also expensive to produce because the fasteners are threaded over the cables and crimped by hand. 
     Double tucked cable mesh is another prior-art cable mesh. It is available through Carlos&#39; Designs of Las Vegas, Nev., as well as other mesh manufacturers. It is hand-manufactured so that the individual cables zig-zag back and forth to join alternatively, in a knotless connection, to the adjacent cable on either side. Due to the process of spreading one cable apart so the other can be threaded through the opening, this method requires relatively thick cables to permit separation of the strands. 
     Single-tucked and hog ringed cable mesh is another prior-art cable mesh. It is produced by International Cordage, Inc. It advantageously employs hog-rings at cable intersections for faster production. Unfortunately, the connections tend to slide, and the cables are also thick. It is relatively labor intensive to produce. 
     Hog-ringed cable mesh is a less expensive alternative prior-art cable mesh. The cables are advantageously connected without the involvement of threading of wires. Although this mesh is adequate to contain animals that do not place excessive force on the joints, if sufficient tension is placed on any connection, then the cables may slip through the hog rings, forming an opening through which an animal may pass. 
     Cast-metal connected cable meshes are manufactured in Germany by Pfeifer Nets. The wires are bonded at each intersection with a small cast-metal sphere, so that the sphere rigidly encases the cables. Unlike the connections on hog-ring meshes, these cast-in-place connectors do not slip. They are however, expensive to procure, very visible, and are not practical for use with fine-gauge cables. 
     Turning now to non-cable meshes, welded wire fabrics are available in very fine gauges. They are useful for containing birds and smaller mammals. However, the quality of the welds tends to be inconsistent, and fatigued wires may break upon repeated flexing. 
     A mesh known as, Phantom Mesh™, is available through A thru Z Consulting and Distributing, Inc. It is appropriate as a low-cost and less-visible containment barrier. It is not a cable mesh. Its design is like that of a chain link, although lighter-gauge wires are used. Although the curved and spiraled contours of the wires reduce visual reflectivity, the wires are however relatively thick and closely spaced, and tend to be noticeably visible. 
     Another mesh called, Zoomesh™, is machine-knitted using a fine wire to form loosely interlocking rows. It is suitable for containing smaller birds and mammals. However, due to lack of wire bonding, the knitting can be snagged. Its fine meshing is difficult to frame, yet noticeably visible to the eyes. 
     Poultry netting, or a chicken wire, is cheap and offers reasonable visibility, but it is weak and susceptible to breaks when considered for permanent animal housing. 
     Non-metallic meshes and nets are suitable for some aviary construction. However, non-metallic meshes and nets have been known to be susceptible to chewing by mammals, particularly rodents that may be preying after the feed grain. Similarly, birds are often at risk to predators when housed in aviaries constructed of synthetic materials, because predators have been known to tear and chew through non-metallic meshes and nets. 
     Most fishnets are non-metallic nets. They are machine tied in large quantities. The prior art net-making machines are generally intricate, expensive, and made for volume production. They are specific to handling of pliable cords for fishnets, and are not known in the industry to be readily adaptable to handling metallic cables, which are not as pliable as the cords for fishnets. 
     One example of a non-metallic netting is a hand-tied fishnet. This traditional hand-tying technique involves the use of an elongated netting needle. The netting needles are generally narrow. A reasonably large quantity of cord is wrapped around a netting needle. The netting is created by forming a long row of loops, to which is tied a second row of loops, and then a third, etc. The netting needles are narrow because an entire supply of cord must pass through the loop of previously tied mesh to which the new knot is being tied. 
     This technique of tying a net is ill-suited for modern-day purposes. The process of passing the entire supply of cord on a needle through each loop must be done by hand. Also, the amount of the available cord is limited by the size of the mesh through which the needle passes. These limitations necessitate frequent splicing of cords to produce nets of large size. 
     The aforementioned prior-art meshes and nets do not satisfactorily meet certain barrier use requirements where strength, see-through visibility, mesh integrity, and ease of production are all high selection criteria. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     An improved animal barrier material and an improved fastening system to simplify its knotting process are disclosed. The animal barrier material comprises a see-through cable netting characterized by strong and secure wire-to-wire connections. An improved fastening system may be employed to simplify knotting and produce superior wire-to-wire connections. 
     Accordingly, one of the objects of the present invention is to provide a fine-gauge cable netting characterized by strong and secure wire-to-wire connections. 
     Another object of the present invention is to provide a superior see-through netting for simultaneous containment and visual enjoyment of zoo animals. 
     Another object of the present invention is to provide a superior see-through wire netting characterized by secure and slip-free wire-to-wire connections. 
     Another object of the present invention is to utilize a knotting process for connecting fine cables into a superior see-through wire netting characterized by secure and slip-free wire-to-wire connections. 
     Another object of the present invention is to provide alternatively fastened nettings of fine gauges using fine, but secure, cable fasteners not prone to slippage or breakage with use. 
     These and other features, objects, and advantages of the present invention are described or implicit in the following detailed description of various preferred embodiments. 
     Since the filing of the parent Patent Application, it has been determined that the preferred embodiment of the present invention comprises a wire mesh netting made up of a plurality of multi-stranded cables, with adjacent pairs of such cables being tied together using an overhand knot, as illustrated, for example, in FIG. 6. 
    
    
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
     FIG. 1 is a side view of a partially constructed improved cable netting being constructed with a single spooled cable under an improved fastening system for nets, meshes, and the like. 
     FIG. 2 is a side view of a partially constructed improved cable netting which uses a different knot. 
     FIG. 3 is a perspective view of a partially constructed cylindrical netting embodiment. 
     FIG. 4 is a side view of a partially constructed barbed-wire style netting embodiment. 
     FIG. 5 is a layout of a partially constructed cable netting of the preferred embodiment of the present invention using regularly patterned peg arrangement. 
     FIG. 6 is a magnified view of a pair of interlocking knots, before and after completion of a knot of the preferred embodiment of the present invention. 
     FIG. 7 is a side view of separated upper and lower overhand knots of an alternative swivel-knot embodiment. 
     FIG. 8 is a top view of separated upper and lower overhand knots of an alternative swivel-knot embodiment. 
     FIG. 9 is a side view of interlocked upper and lower knots of an alternative swivel-knot embodiment. 
     FIG. 10 is an alternate cable netting using staples to form a mesh. 
     FIG. 11 is a side cut-away profile of an exemplary staple holding a pair of cables. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Best Mode Description 
     An improved animal barrier material comprising a see-through cable netting characterized by strong and secure cable (or strand) connections is disclosed, along with an improved fastening system for netting, meshes, and the like. (Here, &#34;cable&#34; shall refer to both a strand comprising twisted wires and also a cable comprising strands.) The cable connections are essentially cable knots achieved with the employment of the improved fastening system, which simplified knotting or tying of the basic cable material comprising the see-through cable netting. 
     The cable material may be a cable further comprised of a plurality of metallic wires or strands, preferably of stainless steel wires and strands. Table 1 tabulates the finer grades of cables by tensile strength. They were found suitable for various knotted cable nettings. 
     The utilized cables may be obtained from the Sevenstrand Tackle Corporation of Long Beach, Calif. These cables are stainless steel cables typically ranging from 1∴7 to 7×7 in wire/strand compositions. However, it is entirely possible that other wire/strand mixes and other metallic compositions yielding finer gauges of cable would also be suitable for the present purposes. 
     
                       TABLE 1______________________________________Table of Stainless Steel Cables.  WIRES/STRANDS         TENSILE STRENGTH                        MEAS. DIA.______________________________________1 × 7   18       lbs.      0.011&#34;1 × 7            lbs.               0.012&#34;1 × 7            lbs.               0.015&#34;1 × 7            lbs.               0.018&#34;1 × 7            lbs.               0.024&#34;1 × 7            lbs.              0.027&#34;1 × 7            lbs.              0.033&#34;7 × 7            lbs.              0.036&#34;1 × 7            lbs.              0.039&#34;______________________________________ 
    
     Examples of the typical mesh/cable mixes used for the presently prototyped nettings are as follows: A 2&#34;×2&#34; (4&#34; stretched) meshed netting may be produced with a 60 lbs. tensile strength 1×7 cable using simple knots and multiple spools; a smaller meshings of 1&#34;×1&#34; and 5/8-5/8,&#34; appropriate for aviaries, may use a 27 lbs. tensile strength 1×7 cable using simple knots and multiple spools; a hand-tied swivel-knot netting having 3&#34;×3&#34; meshes may be produced with multiple spools of either 175 lbs. tensile strength 7×7 cables or 170 lbs. tensile strength 1×7 cables. However, these mesh/knot/cable combinations are only exemplary of the best embodiment, and other matrices of mesh/knot/cable mixes are certainly within the realm of this invention. 
     The invention utilizes an improved fastening system for netting, meshes, and the like, which is a simplified knotting process for manufacturing a superior see-through cable netting. This process allows production of netting from a single spool of material, of any length or size, which never has to pass through a loop. It allows mesh to be tied with any size opening, large or small. Particularly with the thinner gauges, this process of using knots to connect the individual cables was found demonstrably superior to prior-art cable meshes in terms of fail-safe and low-visibility characteristics. 
     After testing several embodiments as disclosed herein, applicant has implemented a technique embodiment of FIG. 6 as the preferred embodiment. In the arrangement of FIG. 5, spools may be arranged in alternate pairs of the spools to keep them organized. FIG. 5 is a layout of a partially constructed cable netting using regularly patterned peg arrangement. For example, where each one of a regularly patterned peg arrangement is shown, a peg 23 is used to hang the cables 24 to tie the knots 21 and 22. Shown in FIG. 6 is a magnified view of a pair of interlocking knots 21 and 22, before and after completion of a knot (The peg is not shown). 
     In operation, two adjacent spools of cable may be taken together and tied into a simple overhand knot. The know may then be tightened over one of pegs 23 which may be provided to insure even spacing of the knots. Generally, adjacent spools may be divided into two sets of pairs which in turn are alternately knotted to produce successive rows of knots. However, maintaining a specific spool within a pair is not necessary to the construction of the present invention. In particular, it may be possible, when knotting spools, to &#34;walk&#34; a spool across the row a spools during each successive knotting row. 
     The resultant knot has been shown to provide superior strength by reducing or eliminating points where the knot may fatigue. Moreover, then used as an enclosure, the netting may not be visible to the naked eye at a distance, as the knots, when tightened, then to be fairly small and unnoticeable. 
     Such various modifications may be made in and to the above described embodiment without departing from the spirit and scope of this invention. For example, the basic cable material need not be stainless steel. Any flexible cable material of nonmetallic composition utilizing the disclosed tying techniques would be within the scope of this invention. Furthermore, the tying techniques do show promise of automation, and would be equally applicable in automated production environments. 
     Description of the Improved Fastening System 
     An improved fastening system simplifies a knotting process for netting, meshes, and the like. It involves repetitively tying one continuous flexible member, originating from one spool, to itself at regular intervals to form knots. The repetitive knots do not require passing the spool through any previously-tied portion of the net. On the other hand, the repetitive knots facilitate construction of a netting from one single spool. The improved fastening system does not require the flexible member to be a cable. The flexible member need only be a cord subject to bending and tying to produce knots. 
     Shown in FIG. 1 are short portions of a main cable 13 which are doubled to form a series of doubled side loops 12. A doubled side loop 12 is then tied to a doubled loop 11 of the previous row, which step of tying consequently forms a new row of loops to which the next row will be anchored. 
     The doubling of a section of a single and continuous cable 13 forms a functional free &#34;end&#34; 10, where no &#34;end&#34; actually exists, which can then be tied to a previously-formed loop 11 in any desired configuration to produce a netting. 
     Knotting of a doubled section with an existing loop may take on a different configuration. Shown in FIG. 2 is a netting which uses a different knot. In either instance, the free end 10 may be made to protrude from the knot. 
     The above improved fastening system has its chief advantage in that it eliminates the need to handle the cable spool during knotting. 
     A Cylindrical Netting Construction 
     To construct a cylindrical netting utilizing the improved fastening system, a main cable is substantially laid in a circle. The forming and knotting path lies substantially on a cylinder. By repeating the group of forming and knotting steps along additional paths which lie on the cylinder, a tubular netting 16 may be generated. 
     Shown in FIG. 3 is a cylindrical netting in formation. By cutting the tubular netting 16 lengthwise, a square or rectangular netting is produced. 
     An Alternative Barbed-Wire Style Netting Embodiment 
     Another possible outgrowth of the improved fastening system for netting, meshes, and the like is an alternative barbed-wire style netting embodiment. As shown in FIG. 4, knots 14 are formed with an extra-long tail, where the tail is the protruding end of a doubled section of a single cable 13. The tips of each tail may be cut for separation, permitting the resulting separated ends to be unraveled. The cuts result in a tuft of radiating, sharp-tipped cable spines 15. 
     The sharp-tipped cable spines 15, when directed outward from an enclosure, would likely be an effective deterrent to intrusion. Particularly when deployed in a zoo environment, it would deter outside predatory intrusions into zoo confinements. 
     An Alternative Knotted Cable Embodiment 
     Alternative efforts to develop a reasonably fast method for tying a cable netting lead to an investigation of overhand knots. Unlike the improved fastening system, these efforts focused on knotting chiefly by hand. In addition, a multiplicity of cable spools were utilized in pairs. Cables were selected from the group shown in Table 1. 
     The first workable process involved a pair of tall spindles that were fastened to a board. One hundred eight spools of cable were stacked on the left spindle, each adjoining pair of spools designated as alternating &#34;A&#34; and &#34;B&#34; spools, with the first spool on top being the &#34;A&#34; spool. Then, by lifting one pair of spools from the spindle at a time, two cables could be tied together (&#34;A&#34; to &#34;B&#34;), and the spools would then be moved to the empty spindle on the right. 
     Following this method, the entire stack of spools was tied in pairs and transferred, two at a time, to the right-hand spindle, so that the first &#34;A&#34; spool resulted on the bottom and the last &#34;B&#34; spool resulted on top. Next, the process was repeated in reverse, but the top spool (&#34;B&#34;) was transferred back to the left spindle without tying it to the &#34;A&#34; spool below. This caused the next row of knots to be tied &#34;B&#34; to &#34;A,&#34; with one non-tied &#34;A&#34; cable left over at the end of the row. By alternating this process repeatedly, a sheet of diamond-patterned netting was created. 
     The employed method helped to separate the cables and prevent entanglements. By measuring the desired interval from each previous row of knots and then kinking the cables at that location by bending them over the edge of a thin metal blade, each row of knots was placed at the correct spacing. 
     An improvement to the spindle approach was achieved with the use of a revolving drum, through which protruded a grid of retractable pins. This eliminated time wasted in rotating the racks, and kept the waiting rows of unused pins out of the way while knots were being tied on the active row. 
     Further improvements were possible in the arrangement of alternate pairing of the spools and keeping them organized. For example, shown in FIG. 5 is a layout of a partially constructed cable netting using regularly patterned peg arrangement. For example, where each one of a regularly patterned peg arrangement is shown, a peg 23 is used to hang the cables 24 to tie the knots 21 and 22. Shown in FIG. 6 is a magnified view of a pair of interlocking knots 21 and 22, before and after completion of a knot. (The peg is not shown.) The resulting netting is the same as would have been produced by utilizing the above manual tying procedure. 
     Such various modifications may be made in and to the above described embodiment without departing from the spirit and scope of this invention. For example, the basic cable material need not be stainless steel. Any flexible cable material of nonmetallic composition utilizing the disclosed tying techniques would be within the scope of this invention. Furthermore, the tying techniques do show promise of automation, and would be equally applicable in automated production environments. 
     An Alternative Swivel-Knot Embodiment 
     Hand-tied interlocking swivel-knotted nettings were conceived mainly to combat cable weakening and breakage associated with efforts to contain animals with nettings having fixedly-tied knots. The fatiguing of prior art nettings was observed due to repeated contacts with animals, which contacts flex and break joints around fixedly-tied knots. The knotting for the swivel-knotted nettings, as conceived, comprises two loosely swiveling knots with respect to each other, which configuration avoids fatiguing of the comprising cables upon repeated animal contacts. 
     As earlier exemplified, a hand-tied swivel-knot netting may have the larger 3&#34;×3&#34; meshes produced with multiple spools of 175 lbs. tensile strength 7×7 cable. The swivel knots could be tied fairly quickly and will not slip. However, unlike the improved fastening system, numerous cables are required. 
     Shown in FIG. 7 is a side view of separated upper and lower knots of the present alternative swivel-knot embodiment. Although both upper 17 and lower 18 knots are forms of overhand knots, these knots are tied differently from each other. Shown in FIG. 8 is a top view of separated upper and lower knots of the present swivel-knot embodiment. 
     FIG. 9 is a side view of interlocked upper 17 and lower 18 knots of the present alternative swivel-knot embodiment utilizing cables 19 and 20. 
     The processes employed in tying the above knots were generally slow and tedious. However, the procedures described are susceptible to automation, and such automation is within the scope of the present invention. 
     Alternative Crimped and Stapled Netting Embodiments 
     Other investigations to develop a reasonably fast method for manufacturing a cable netting lead to an investigation of crimped nets. Unlike either of the improved fastening system or the interlocked pairs of swivel knots (overhand knots), crimped cable nets were investigated. The netting material was a 0.027 1×7 Toothy Critter Wire™, manufactured by the Seven Strand Corporation. A regular layout of a plurality of those cables was joined at regular intervals and crimped with a separate connector at each cable joints. 
     A close variant of a crimped connection is a stapled connection. Shown in FIG. 10 is an alternate cable netting 25 using staples 26 to form a mesh. The staples 26 offer the advantage of manufacturing the netting as a cylinder. 
     A single, fixed stapling mechanism may be used for production of a stapled netting. A single spool of cable which is wound in a close spiral around a drum may supply a quantity of cable for feeding to the stapling mechanism. Staples are applied at regular intervals as the cable drum rotates past the stapling mechanism. 
     Shown in FIG. 11 is a cut-away profile of an exemplary staple 26 holding a pair of cables 27 and 28. The staple may overlap when stapled. The size of the staple is small to maintain see-through visibility for finer cables. 
     It is intended that the forgoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, which are intended to define the scope of this invention.