Abstract:
A protective lens shield (12) with a torsion adjustment system (3) and simple one-bolt mounting bracket clamp (1) for use with outdoor lighting fixtures. The protective lens shield is constructed of dual layers and thicknesses of polycarbonate sheets (12) which have ballistic containment properties. The bracket clamp (1), clamp bolt assembly (2), adjustment carriage bolt (3), threaded adjustment housing (4), and arm-shield adjustment arm (5) are constructed of steel with a galvanized coating for a corrosion resistant longer life. The hook-and-cable assembly (FIG. 2) is comprised of a hook (8), cable (9), and a cable assembly bolt (10) which is stainless steel corrosion resistant materials. The torsion flex system is enhanced by the adjustable torsion carriage bolt (3). This adjustment allows for a flex in the polycarbonate sheets allowing it to absorb the energy from objects attempting to penetrate the shield (12). The rubber grommets (11) allow for movement, yet they hold the polycarbonate sheets together to perform the task of an expansion joint. The hook-and-cable assembly (FIG. 2) allows for a custom attachment to the existing light lens cover (6A) no matter where the location of the interior gussets are positioned. This custom attachment allows this protection shield to adapt to any make or model cobra head street light. Similarly, the protective shield may be molded into a variety of configurations to protect the various lighting fixtures. This protective shield is lightweight, easily attached to the pole arm (13), and swings away for easy luminaire maintenance.

Description:
This application is a continuation-in-part application of application U.S. Ser. No. 08/356,976 filed Feb. 7, 1995, now U.S. Pat. No. 5,651,612, for a TORSION FLEX SHIELD (FLAT) PROTECTIVE LENS SHIELD WITH TORSION MOUNTING BRACKET. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to outdoor lighting fixtures, such as street lights, or luminaries and, more particularly, to a protective lens shield designed with a special torsion mounting bracket for such light-diffusing lenses of outdoor street lighting and/or luminaries. 
     2. Description of Related Art 
     Outdoor street lighting fixtures customarily have a light lens which covers the light-producing means emitting light from the luminaires. This lens is conventionally constructed of glass, which makes it vulnerable to frequent breakage by vandalism. Because of lens breakage, increased maintenance costs are incurred in order to properly maintain the quality of outdoor street lighting. The lens diffuses and protects the light from the light-producing means of the luminaires. Lens breakage may subject persons to increased crime, injury, drug trafficking, and unsafe auto/pedestrian travel due to nonfunctioning street lights. Lens breakage may also create injury due to broken glass. 
     Historically, light-diffusing lenses have been made of synthetic products such as polycarbonate resin, which has a greater impact resistance, and is subject to less breakage than glass. These replacement lenses are subject to less breakage than glass, but forming an impact resistant synthetic into a complex shape and structure required to diffuse the light into a desired plan is expensive. Outdoor street lights have shown a trend toward higher output sources which produce more heat and ultraviolet radiation which can discolor and even deform synthetic lenses, especially when placed close to the luminaire light-producing means, where they are most effective to diffuse the light. 
     Escalating crime and violence continues to increase in the 1990&#39;s, which has created the need for a high performance protective shield for outdoor street lighting fixtures. This shield not only needs to protect the light producing means of the luminaire and light lens to allow it to perform the normal function of an outdoor street light, but it needs to have a several capabilities not previously required of a protective light shield. These features need to include the following: 
     (a) Ballistic resistance with no spalling or breakage to not only protect the light from the bullet, but have the ability to capture the bullet so that it will not bounce from the shield to cause damage or injury elsewhere. 
     (b) The containment properties of the light shield must not obscure the quality of light transmission from the light lens to streets, sideways, walkways, etc. 
     (c) Simplified installation to decrease labor costs, but allow for easy maintenance of light fixture for bulb replacement. 
     U.S. Pat. No. 3,315,072 is an invention which relates to luminaries and, more particularly, to means for mounting the reflector and retractor to a luminaire having a sealed optical assembly. It also provides for new and improved means for mounting a luminaire optical assembly with independent latch spring members. 
     U.S. Pat. No. 4,010,362 is a shield which is permanently mounted to outdoor luminaries to prevent entry of birds into the interior. This protective shield only offers protection from birds to prevent the building of nests and living quarters. 
     U.S. Pat. No. 4,160,286 is a transparent hemispherical shield formed of polycarbonate resin plastic which was mounted to the existing fixture to cover a bulging bowl-shaped light diffusing glass lens of a luminaire to protect such lens. The hemispherical shape was structurally sound and placed a substantial distance outward the bulging light-diffusing lens to eliminate the chance of discoloration by heat. This invention is secured by return bent clips and lacks the torsion flex adjustment. 
     U.S. Pat. No. 4,432,045 is a transparent low profile shield in the form of a pan shield having a central bulge in the shape of a spherical segment. This shield was mounted with shield-mounting screws to the existing fixture. This invention does not have a simple one-bolt installation, torsion adjustment, or teardrop shape. 
     U.S. Pat. No. 4,460,945 is a laminate plate made from &#34;Lexgard™&#34; mounted in a spaced relationship from the lens of the luminaires. This plate is a transparent shield mounted with (4) bolts countersunk through holes which are bored on the bottom of the housing. This invention does not have a torsion adjustment, or simple one-bolt installation. &#34;Lexgard™&#34; is a laminate between which there is a thick layer of acrylic. The purpose of the acrylic is to trap an object of penetration, yet acrylic shatters with a splinter effect, which greatly affects the clear appearance of the shield and obscures the transmission of light. 
     All of the prior inventions have one or more of the following disadvantages: 
     (a) The lens cover is a round sphere which directly connects to the housing for the protection of the glass lens from distinctly small damaging items. 
     (b) The protective shield only offers protection from birds and other small inhabitants. 
     (c) The protective shields and/or covers directly attach to the light fixture with independent latches, clip, or bolts. 
     (d) Drilling or alteration of the existing light fixture is necessary for proper installation. 
     (e) No torsion adjustment to allow for energy absorption from the object which is trying to cause damage to the light lens. 
     (f) No form of attachment to the lens cover door to allow for the gusset locations which are inconsistent in the different models of cobra head street lighting fixtures manufactured. 
     (g) &#34;Lexgard™&#34;, as specified in U.S. Pat. No. 4,460,945, is an acrylic property which shatters with a splintering effect when a bullet attempts to penetrate a light shield made of &#34;Lexgard™&#34;. This penetration distorts the shield appearance and obscures the quality of light penetration. 
     (h) No bracket assembly providing a form of attachment on the pole arm. 
     (i) No dual layering using two types and thicknesses of polycarbonate sheets to achieve adequate ballistic protection, bullet containment with minimal distortion of shield clarity. 
     (j) No energy absorption to protect the fixture from an objects impact. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Accordingly, several objects and advantages of my present invention are: 
     (a) Provides shield protection with dual polycarbonate sheets which are UV stabilized. 
     (b) Provides protection against vandalism, forced entry, and accidental damage. 
     (c) Provides containment properties for vandalism from small arms (22 to 44 caliber) with no spalling or breakage. 
     (d) Provides a torsion flex system with an adjustment bolt which allows the protective shield to flex and absorb the energy from objects of forced entry such as bullets from small arms (22 to 44 caliber), rocks, small projectiles, etc. 
     (e) Provides a torsion flex system which is galvanized to allow for a longer corrosion resistant life. 
     (f) Provides a simple one-bolt installation with a clamp and bolt assembly which is galvanized and is mounted to the pole arm and not the light fixture. 
     (g) Provides a hook-and-cable assembly which is stainless steel to allow for a longer corrosion resistant life and provides a custom attachment to the existing lens door. 
     (h) Provides for easy fixture maintenance by dropping away for bulb access. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, and in which like reference numerals designate like parts throughout the figures thereof. 
     FIG. 1 shows the torsion flex adjustment screw and one-bolt mounting bracket as attached to the pole arm. FIG. 1 is a view in detail of the portion indicated by the items 1 through 7, 12, and 13 of FIG. 3. 
     FIG. 2 shows the hook-and-cable assembly. FIG. 2 is a view in detail of the portion indicated by the items 8 through 12 of FIG. 3. 
     FIG. 3 shows the torsion flex shield (flat) with the one-bolt mounting bracket, torsion adjustment screw, hook-and-cable assembly, as mounted on an existing cobra head outdoor street lighting fixture. 
     FIG. 4 shows a second embodiment of the torsion flex shield having side protection. 
     FIG. 5 shows the second embodiment mounted on a street light fixture. 
     FIG. 6 shows a side view of a third embodiment of the torsion flex shield specifically adapted for use with drop lens fixtures. 
     FIG. 7 shows an end view of the third embodiment of the torsion flex shield. 
     FIG. 8 shows a fourth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This invention is a protective lens shield with a torsion mounting bracket. This shield is designed primarily to stop small arms fire and vandalism from damaging cobra head outdoor street lights. By incorporating the latest technology, the inventor has been able to provide lens and luminaire protection which has excellent ballistic resistance, easy fixture maintenance and installation, as well as a torsion adjustment to absorb the energy from objects such as vandalism by small arms (22 to 44 caliber). 
     FIG. 3 shows a side profile of the torsion flex shield (flat). This shield is mounted to a pole arm (13) of a cobra head street lighting luminaire (6). FIG. 1 is a detail view of a galvanized coated steel clamp, bolt, and torsion adjustment system. FIG. 2 is a detail of a stainless steel hook-and-cable assembly. FIG. 1 and FIG. 2 are the primary connecting, mounting, and adjustment features of FIG. 3. 
     A shield is attached to a pole arm with a torsion bracket assembly (1-5, 7). A bracket assembly (1-5, 7) and (FIG. 1) is comprised of a galvanized coated steel bracket clamp (1) which opens and clips over an existing pole arm (13). A galvanized coated steel bolt assembly (2) secures a galvanized coated steel bracket clamp (1) to an existing pole arm (13) and attaches a galvanized coated steel arm-shield adjustment arm (5) to a galvanized coated steel bracket clamp (1). A galvanized coated steel bolt assembly (2) is tightened to ensure a secure connection between a pole arm (13) and a galvanized coated steel arm-shield adjustment arm (5). 
     A galvanized coated steel arm-shield adjustment arm (5) has a galvanized coated steel threaded adjustment housing (4) permanently attached at an approximate 42-degree angle so as to meet a pole arm (13) when a galvanized coated steel arm shield adjustment arm (5) is properly attached to a galvanized coated steel bracket clamp (1). A galvanized coated steel threaded adjustment carriage bolt (3) is inserted into a galvanized coated steel threaded adjustment housing (4) and screwed in. A galvanized coated steel adjustment carriage bolt (3) is not screwed in tightly, since this bolt (3) is the torsion adjustment bolt which will be detailed in the &#34;Operation&#34; section of this patent application. 
     (FIG. 1) A galvanized coated steel arm-shield adjustment arm (5) has a flange at the base of the arm which contains three holes which match up to three holes that are drilled into the flat polycarbonate sheets (12) at the flat base of the teardrop-shaped sheets. Three assembly bolts (7) are used to connect a galvanized coated steel arm shield adjustment arm (5) to flat modified teardrop-shaped polycarbonate sheets which are UV stabilized (12). The polycarbonate flat protective glazing sheets (12) can vary in thickness, depending on the degree of protection required. The flat polycarbonate protective glazing sheets (12) are cut into a teardrop shape with a flat base. Approximate measurements for a small shield (50 to 100 watt light luminaires would be a width of 15&#34;, length 28&#34;, with a teardrop base of 7&#34;. The teardrop shape can be modified by enlarging the width or length depending on the area of coverage needed. A galvanized coated steel torsion adjustment system (FIG. 1) and a hook-and-cable assembly (FIG. 2) would not be affected by modification of the teardrop-shaped polycarbonate sheets. 
     Two holes are drilled into a curved top area of the flat teardrop-shaped polycarbonate sheets to allow for attachment of a stainless steel cable assembly bolt (10) and insertion of two rubber grommets (11). Each of the two holes will contain an assembly comprised of the following, which will become a stainless steel hook-and-cable assembly which is detailed in FIG. 2. 
     (FIG. 2) A stainless steel hook-and-cable assembly is a pair of hooks which connects the flat teardrop-shaped polycarbonate sheets (12) to a lens door of a cobra head luminaire (6A). These stainless steel hooks (8) are important because they allow for a custom attachment to an existing lens door on one of various models of cobra head light luminaries. Gussets inside a lens doors (6A) are placed by manufacturers at inconsistent locations making a standardized hook attachment unfeasible. A hook-and-cable assembly (FIG. 2) is assembled in this manner. A stainless steel hook (8) is permanently connected to a stainless steel cable (9) which is permanently attached to a stainless steel cable assembly bolt (10). A stainless steel bolt assembly (8, 9, 10) becomes a single assembly. An assembly (8, 9, 10) then receives a stainless steel washer and rubber grommet (11) which is then inserted through a hole which has been drilled in the curved top area of the teardrop-shaped polycarbonate sheets (12). A stainless steel cable bolt assembly (8, 9, 10) then receives another rubber grommet (11), stainless steel washer and stainless steel nut to complete an assembly. A nut is then tightened to secure a stainless steel hook-and-cable assembly (FIG. 2) on the flat polycarbonate sheets (12). 
     FIG. 4 shows a second embodiment of the present invention wherein the torsion flex shield 20 is formed with protective sides to provide increased protection against projectiles. The protective shield 20 is formed using a dual layer of polycarbonate glazing sheets which have been vacuum formed from a custom designed mold to allow for additional protection of the light lens, and yet still retain the ballistic properties of the polycarbonate glazing sheets. 
     FIG. 5 shows the second embodiment of the present invention attached to a street light fixture. Notice that the sides of the protective shield 20 provide increased protection from projectiles. 
     FIG. 6 is a side view of a third embodiment of the present invention wherein the torsion flex shield 22 is formed with a drop lens for use with outdoor street lights having a drop lens configuration. The protective shield 22 is formed by using a dual layer of polycarbonate glazing sheets which have been vacuum formed from a custom designed mold to allow for the curved contour of the drop lens, and yet still retain the ballistic properties of the polycarbonate glazing sheets. The protective shield 22 may be custom molded to fit the desired contours of existing or future drop lens designs. FIG. 7 is an end view of the third embodiment. 
     FIG. 8 illustrates another embodiment of the present invention, in which there is no separate torsion means, such as the torsion adjustment bolt (3), to flex the shield. The polycarbonate sheets (12) are placed under a small tensioning force by operation of the bracket clamp (1), the angle of attachment of the adjustment arm (5), and the tension of the hook and cable assemblies (8,9). The angle of attachment of the adjustment arm can be modified as desired to enhance the natural flexing of the polycarbonate sheets (12) caused by the hook and cable assemblies (8,9). The bracket clamp (1) and adjustment arm (5) may even be designed as one unitary piece to facilitate the natural flexing effect. This limits the ease of installation and removal, but may be used without departing from the scope of the present invention. The tensioning force is obviously not as great as in the preferred embodiment, wherein the torsion adjustment bolt (3) is used, but for certain applications, the tensioning force may be sufficient to provide the necessary flex of the polycarbonate sheets (12). 
     Operation: 
     A torsion flex shield is a protective shield designed for Cobra head style outdoor street light fixtures. This shield operates by providing protection to the entire bottom portion of a luminaires including the light lens. The protection provided by this shield offers people, places, and things quality street lighting that is not damaged by vandalism, small bullets, rocks, projectiles, or objects of forced entry. 
     Once installed properly, a torsion flex protection shield will minimize repair and maintenance costs by protecting the light lens and luminaires. The existing light lens will last longer and uninterrupted street lighting will be maintained. 
     This invention is very easily installed on an existing pole arm (13) of a cobra head street light luminaire (6). To install, remove the galvanized coated steel clamp bolt assembly (2) from the galvanized coated steel arm-shield adjustment arm (5). Install the galvanized coated steel clamp (1) on an existing pole arm (13) and attach to the galvanized coated steel arm-shield adjustment arm (5) with the galvanized coated steel clamp bolt assembly. Secure bolt and nut to tighten. Open existing lens door (6A) of luminaire (6) and attach both stainless steel hooks (8) over the edge of lens door (6A), making sure to avoid placing hooks where the interior gussets are located. Position lens door (6A) so that it is one inch from being closed. Adjust galvanized coated steel carriage bolt (3) to touch pole arm (13). This adjustment is what creates the torsion flex in the polycarbonate sheets so that energy will be absorbed when objects attempt to penetrate its surface. Penetrating objects, such as bullets, will penetrate the outer layer of polycarbonate and become trapped and/or embedded between the two layers. This feature protects the light lens, as well as eliminates an object such as a bullet to bounce from the shield elsewhere. The rubber grommets located on each side of the polycarbonate sheets allow the flex of energy absorption to give, yet hold the two sheets together. The grommets act very much like expansion joints. The torsion flex also allows for a shield to have the ability to be installed on a cobra head luminaire no matter what lighting angle the fixture has been positioned. The final step to install the protection shield is to close lens door (6A) by applying pressure with your hands. Make sure lens door (6A) is properly locked. Go back to the galvanized clamp bolt (2) and tighten. 
     The preferred construction illustrated in the drawings has the carriage bolt (3) which adjusts the tension of the flex shield (12) positioned between the adjustment arm (5) and the light pole arm (13). However, the tension of the flex shield may also be adjusted by placing a similar torsion adjustment means between the adjustment arm (5) and the luminairc housing (6) or even between the flex shield (12) and the luminaire housing (6). The present invention may also be practiced without using a carriage bolt (3), but by adjustment of the angle of attachment of the adjustment arm (5) and the polycarbonate sheets (12), the cable and hook assemblies (8,9) may provide sufficient tensioning force for certain applications. The adjustment arm (5) and the bracket clamp (1) may be a unitary piece to facilitate tensioning. The preferred construction, however, is as illustrated in FIG. 3. The important consideration is to provide some degree of flex to the polycarbonate sheets (12) in order to provide energy absorption. 
     Theory of Operation: 
     The torsion flex shield is a protective shield for outdoor street lighting fixtures, primarily those of the cobra head style. The unique qualities of this shield is the torsion flex system. The torsion flex allows for a custom adjustment to a protective shield so that when an object attempts to penetrate, the energy from that object will be absorbed and the shield will flex with the impact. The style of design of this protective shield also allows for it to act like a lighting accessory instead of a fixed part of the light luminaires. It mounts to the pole arm, not the luminaire, and it swings away with the lens door for easy bulb access. 
     The rubber grommets with the flexible cable are actually the elements which absorb the energy of an object to eliminate damage to the fixture. When an object strikes the flex shield, the rubber grommets squish to absorb the impact, the cables bend and then relax, and then the shield returns to the original downward flex, thereby protecting the fixture. 
     The two sheets of polycarbonate are not attached with any adhesive. The trapping effect occurs because the first sheet slows a bullet and the second sheet acts to trap the bullet between the sheets. This eliminates any bullet from hitting and bouncing off the polycarbonate. If the sheets were laminated together, there would be a visible distortion in the plastic, which would distort light transmission through the plastic. If the two sheets were anchored together with bolts on both ends instead of on one end, a bullet could penetrate the first sheet and likely send plastic debris into the light fixture. Thus, the use of the rubber grommets facilitate the energy absorption. The greater the flex of the sheets, the better the energy absorption characteristics of the shield. However, the present invention may be practiced, as discussed above, without a specific torsion adjustment means, since the natural flexing associated with the hook and cables and the polycarbonate sheets provides a level of energy absorption which may, under certain circumstances, be sufficient. 
     Summary Ramifications, and Scope of Invention: 
     Accordingly, you will see that this invention has been created with a desire to design a solution to a present day problem of small arms vandalism in the area of outdoor street lighting. Time, experience, and technology played an important role in designing the end product. 
     Factors which played a significant role in the research and design are: 
     (a) The types of street lights being damaged; 
     (b) The prior and present street light protection available; 
     (c) Luminaire protection as well as lens protection; 
     (d) The type of materials available with ballistic containment properties; 
     (e) The need for a light protection shield which would not mount directly to the luminaire; 
     (f) Weight of the finished product; 
     (g) Affordability of the finished product; 
     (h) Noncorrosive materials; and 
     (i) Appearance. 
     With all of these elements taken into consideration, this invention is new, unique, and provides a solution to a modern day problem. Although the description of the invention contains many specifics, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments of this invention. For example, the flat protective teardrop-shaped shield can have other modified shapes, such as longer and/or wider depending on the size and the area of required protection. The same holds true for the thickness of the polycarbonate sheets and the protection requirements. The height of the sides of the shield may be adjusted to provide desired side protection. Also, the drop lens configuration may similarly be molded to fit any desired drop lens design. 
     Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.