High strength security fence for snaring vehicles

A high strength security fence for resisting penetration by vehicles. The fence has high strength line posts that support a plurality of tensioned high strength cables. In the preferred form, these cables are threaded through the posts. The cables are each encased in a conduit-type rail sheath (i.e., superstructure) that span the distance between the posts. Typically, at least one end of each cable is anchored within the concrete anchor of a post adjacent a line post supporting the cable. Cables can be anchored, and tensioned, at corner buttresses if desired. To improve the aesthetic appearance of the fence and to add further strength, the posts and rails can be encased in decorative superstructures, and vertical strengthening bars are joined to the rail superstructure. A clamp is described for joining the high strength fence to upright posts of conventional chain link fences or the like.

TECHNICAL FIELD 
This invention relates generally to fences which are used to enclose an 
area to be protected, such as real property, and more particularly to high 
strength fences designed to preclude intrusion, and specifically high 
impact vehicular intrusion into a secured area. The fence includes unique 
methods and apparatus for withstanding strong impact of a potentially 
intruding vehicle. 
BACKGROUND ART 
Fences are commonly used to define the borders of real property and other 
areas to be protected and to discourage intrusion into the enclosed areas. 
A wide variety of fences are, of course, well known in the art and 
typically include fence posts variously anchored in the ground at 
preselected intervals and either a series of rails or cables affixed to 
and extending horizontally between the fence posts. Alternatively, various 
configurations of wire, mesh or other substances are variously attached to 
and extend between the fence posts. 
A primary drawback of the prior art fences is their lack of strength. They 
are designed only to discourage rather than to prevent intrusion and 
cannot, for example, withstand the strong impact of high-speed vehicular 
intrusion attempts. Additionally, even known prior art high-strength 
boundaries have typically focused on the material of which they are 
constructed for their strength and have not provided a high-strength cable 
and impact-resistant anchor means for maintaining the fence in a 
substantially vertical position after impact. Moreover, known prior art 
boundaries have not combined strength with an aesthetically pleasing and 
deceptive but typical-looking exterior fence design even though such a 
deceptive appearance is highly desirable in many security applications, 
such as at diplomatic embassies, etc. 
Since it is desirable to prevent vehicular intrusions, particularly at 
locations such as secure government and military installations, it is an 
object of the present invention to provide unique means and apparatus for 
preventing penetration of a fence by an intruding vehicle. 
It is a further object of the present invention to provide unique means and 
apparatus for anchoring and tensioning the high strength fence cables. 
Additionally, to further enhance the invention's ability to stop vehicular 
intrusion attempts, a further object of the invention is to provide unique 
means and apparatus for supporting and anchoring the fence. 
Another object of the present invention is to maintain an aesthetically 
pleasing and deceptive appearance by encasing the rail and buttress 
superstructures to give the fence the appearance of a more typical fence 
design, such as a wrought iron fence or a rural, usually wooden, post and 
rail fence. 
Yet another object is to provide a high-strength security fence which is 
constructed of non-deteriorating materials, which will require little 
maintenance and which can be relatively easily adjusted and repaired on 
site. 
It is another object to provide apparatus for the attachment of the impact 
resistant fence to an already existing chain link fence. 
A further object is to provide a high-strength fence which is in part 
prefabricated and thus can be manufactured using a relatively inexpensive 
process. 
Other objects and advantages will become apparent upon a consideration of 
the following drawings and a complete description thereof. 
DISCLOSURE OF THE INVENTION 
The fence of the present invention comprises a snare means for snaring or 
immobilizing an intruding vehicle upon impact. The snare means includes a 
plurality of high strength cables, each of which have two end portions. 
The cables are encased in a conduit or the like and are supported and held 
at selected positions above the surface of the area to be protected with a 
post means. The post means includes one or more posts, each of which 
includes a post superstructure with a first end fixed in the surface of 
the area to be protected, a further end extending vertically from the 
surface. At least one end of the cables can be anchored by corner buttress 
means. Also, one or more ends of the cables can be anchored in the anchor 
means of a post means adjacent a post means supporting the cable. The 
cables are further strengthened by a tensioning means which adjustably 
controls the tension of the cables. Additionally, in a preferred 
embodiment, the fence further comprises a rail superstructure means for 
covering the encased cables between the posts, and vertical strengthening 
rods joined to the rail superstructure means.

BEST MODE FOR CARRYING OUT THE INVENTION 
Referring now to FIG. 1, shown generally at 10 therein is one embodiment of 
a fence constructed in accordance with the various features of the present 
invention. This particular embodiment is a utilitarian type fence for use 
in withstanding the strong impact of high speed vehicular intrusion 
attempts. Although indicated as being formed in a straight line, this 
fence could also take on any contour to enclose a specific area to be 
protected. In this embodiment, there are a plurality of line posts, such 
as indicated at 12 and 12', that can be square in cross section as 
illustrated or can have other suitable cross-sections. Typically, each of 
these line posts extends approximately four feet above ground level. In 
order to have sufficient strength to resist penetration of the fence, 
these line posts 12, 12' are formed of steel, or like materials, and can 
be filled with concrete and reinforcing rods (not shown). These line posts 
are typically separately separated at spacings of about 10 feet, although 
other spacings certainly are within the scope of the invention. For 
purposes to be described in detail hereinafter, posts 14, 14' having a 
larger cross section can be interposed at various positions along the 
length of the fence. These, too, typically are metal and are filled with 
concrete or like materials. Furthermore, they can include reinforcing rods 
if desired or necessary. Typically, the metal of the posts is 1/4 inch 
thick. 
The posts are used to support a plurality of rails, such as indicated at 
16, 18 and 20, as well as the corresponding rails 16', 18' and 20'. Each 
of these rails in this embodiment are formed from a sheath 22 through 
which is threaded a high strength cable 24. This sheath can be typically 
fabricated of galvanized metal, plastic, vinyl, etc. Typically, the cables 
are 1 inch in diameter and have about 105,000 pound tensible strength. 
This construction for rail 16' also includes an outer sheath 22' threaded 
by a high strength cable 24'. The remaining cables are fabricated in a 
similar fashion. Each of the line posts is securely anchored in vertical 
orientation using, for example, approximately three feet of concrete, or 
like material. In order to anchor the larger posts 14, 14', typically, the 
concrete anchor is 6 feet in depth. These concrete anchors are indicated 
at 26, 26', 28 and 28', respectively. 
The function of the larger posts 14, 14', referred to as "super posts", is 
to provide a high strength termination for cables 24, 24' and their 
enclosures 22, 22'. It will be recognized that large high strength cables 
typically are manufactured in standard lengths, such as one hundred feet. 
Since it is difficult to effectively join lengths of such cables, which 
typically are one inch in diameter, the construction of anchoring means in 
FIG. 1 consists of passing the sheath 22 and its cable 24 through super 
post 14 at a point identified at 30. After passing through this post 14, 
the sheath 22 is bent downwardly as indicated at 22A at an angle such that 
the end thereof and its cable terminate at 32 within the concrete anchor 
28' used to anchor super post 14'. It is this construction that is 
referred to hereinafter as "securing an end of the cable in the concrete 
anchor of a post means adjacent a post means supporting the cable". The 
details of the passage of these elements through super post 14 and the 
anchoring will be described in more detail in connection with FIGS. 3 and 
4. It can be seen that the other rails 18 and 20 are likewise passed 
through the super post 14, bent downwardly and anchored in the concrete 
anchor 28' as indicated. In a like manner, rail 16' made up of the 
enclosure 22' and its cable 24' pass through super post 14' at 30' and are 
bent downwardly as indicated at 22A' so as to enter and be anchored at 32' 
in concrete anchor 28 for super post 14. The other rails 18' and 20' are 
similarly anchored as at 32'. A tie bar 33 spans the gap between super 
posts 14, 14' to complete the fence at this point. 
More details of this anchoring system can be understood by referring now to 
FIG. 3 and FIG. 4. In FIG. 3 it can be seen that the super post 14 is 
formed from a shell 34 (typically square in cross section) filled with a 
substance such as concrete as indicated at 36. The enclosure or sheath 22 
having a cable 24 therethrough, passes through the shell 34 as at opening 
38 and exits at the opposite side through an opening 39. If desired to 
strengthen the super post at this point, a sleeve 40 can be used 
surrounding the opening 39. After leaving the super post, the sheath is 
bent downwardly as previously indicated and indicated at 22A in this 
figure. 
In FIG. 4 it is indicated how the actual end of the rail (or cable) is 
anchored into a concrete footing or anchor such as indicated at 28. This 
shows the sheath 22A', having its cable 24' threaded therethrough, passing 
through post 14. As indicated at the opposite surface of the post 14, the 
cable 24' is bent back upon itself, as indicated at 42, with the ends 
secured as with a hardened ring 44 and a clamp 45. Alternately, the clamp 
can be fastened to the end of the cable 24' without forming the loop 42. 
The cable end can be enlarged by other suitable means, also, so as to be 
securely anchored in the concrete. In this way, the cable can be tensioned 
and adequately anchored such that each portion of the fence 10 will 
adequately resist penetration by a high speed vehicle. 
Referring now to FIG. 2, shown at 10' therein is another embodiment of the 
present invention. This particular embodiment is made to be aesthetically 
pleasing and typically looking of fences used in many security 
applications such as at diplomatic embassies, etc. so as to be deceptive 
of its strength. This fence similarly has a plurality of line posts such 
as indicated at 50. These can be constructed internally similar to the 
post shown in FIG. 1 and then encased in a decorative superstructure 52. 
This superstructure 52 typically terminates in a pointed top 54 to achieve 
this aesthetic appearance. This particular embodiment employs five 
substantially parallel rail means as indicated at 56, 58 etc., although 
more or less rails can be utilized in accordance with the present 
invention. In order to make the fence 10' conform to the intended style, 
each of the rails, such as rail 56 is similar to the rails shown in FIG. 
1, except that each has a decorative superstructure such as indicated at 
60. Thus, each rail has a aesthetically pleasant appearance but retains 
the high strength impact resistance characteristics desired for the 
security fence. To further add to the strength of the fence and its 
appearance, a plurality of vertical bars 62 are attached to the exterior 
surface of the superstructures 60 with each terminating in a typical top 
point 64. 
Indicated in this FIG. 2 is the treatment of the security fence of the 
present invention at corners of the fence. A typical corner includes a 
buttress means 66 enclosed in a superstructure 68. This superstructure is 
typically anchored to the ground in a manner similar to the individual 
posts 50. Further, the buttress means typically includes tensioning means 
for the cables of the rails. This tensioning means can be any suitable 
adjustment means to provide the adequate tension of the cables 24 to 
reduce the possibility of penetration of the fence by a high speed 
vehicle. Persons skilled in the art of fences will understand the 
necessity for this tensioning and will understand any suitable means for 
accomplishing the same. Although not shown in this figure, cable 
terminating and clamping means, such as indicated in FIG. 1 at ends of 
cables can be included in the fence where the length of any particular run 
is to exceed the normal length of the cables. This decorative embodiment 
of the present invention can also include a fence base strip as indicated 
at 70. This base strip provides for the easy maintenance of the ground 
proximate the fence such as lawn mowing and trimming. Further, this base 
strip adds to the aesthetic qualities of this embodiment of the fence. In 
this embodiment, the superstructure of the posts and rails are typically 
joined as with welding. Similar construction is used where the rail 
superstructure joins the buttress superstructure. In a similar fashion, 
the vertical reinforcing bars 62 are joined to the rail superstructures as 
by welding. Thus, it is seen that the embodiment of FIG. 2 conforms in 
appearance to fences typically utilized around certain installations. 
There may be applications of the fence of FIG. 1 wherein it is desirable to 
join this security fence to a conventional chain link fence or the like. 
In order to accomplish this type of installation, a clamp such as 
indicated at 72 in FIG. 5 is provided. This clamp 72 is designed to be 
fastened to a conventional post 74 of the chain link fence. The clamp 
consists of two confronting legs 76 and 78 that encircle the post 74 as at 
80. These legs are joined together with, for example, one or more bolt 
units 82. The clamp is provided with an aperture 84 whereby the sheath 22 
of the cable 24 passes therethrough such that the security fence of the 
present invention can be securely attached to the aforementioned post 74 
of a conventional fence. In this manner, the conventional fence posts 74 
provides additional rigidity to the posts of the security fence 10 thereby 
further preventing possible penetration by a vehicle or other object. With 
this construction, the line posts of the high strength security fence can 
be spaced farther apart, e.g., at fifty foot spacing. 
From the foregoing it will be understood by those versed in the art that a 
high security fence construction has been provided to prevent penetration 
by a high speed vehicle or like object. Primary strength is afforded by 
the construction of the posts and the rails that are supported thereby. 
Furthermore, superstructures can be added to these elements to create a 
fence with an aesthetic and deceptive appearance such that its strength 
characteristics are not immediately evident. Suitable terminating means 
for the cables used in each of the rails has been described, in addition, 
such that a practical high strength security fence is provided for any 
type of application. 
Although the present invention has been described with respect to specific 
embodiments, it is not intended that such specific embodiments be 
considered as limitations upon the scope of the invention. The invention 
is to be limited solely by the appended claims and their equivalents when 
read in combination with the detailed description of the apparatus.