Patent Publication Number: US-11639610-B2

Title: High-intensity, telescoping light tower with safety features

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. patent application Ser. No. 17/124,744 filed on Dec. 17, 2022 issuing as U.S. Pat. No. 11,365,555 on Jun. 21, 2022 which in turn claims the benefit of U.S. patent application Ser. No. 16/787,252 filed Feb. 11, 2020 issuing as U.S. Pat. No. 10,871,004 on Dec. 22, 2020, which in turn claims the benefit of U.S. patent application Ser. No. 16/552,190 filed Aug. 27, 2019 issuing as U.S. Pat. No. 10,557,279 on Feb. 11, 2020, which in turn claims the benefit of Ser. No. 15/481,222, filed Apr. 6, 2017 issuing as Patent No. 10393324 on Aug. 27, 2019, which in turn claims the benefit of U.S. Provisional Application No. 62/320,057, filed Apr. 8, 2016, each of which are hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention is in the field of outdoor, mobile lighting. In particular, the invention is directed to a high-intensity mobile lighting unit having certain safety features. 
     Summary of the Invention 
     High-intensity mobile lighting systems are used in a variety of situations. It is common, for example, to see such systems on large construction sites like hydroelectric damn projects, in order to allow work to proceed safely at night. These systems may also be found at various outdoor activities, such as concerts, festivals and the like. Some outdoor sporting events use these types of lighting systems, either as a sole source of lighting, or to supplement fixed lighting systems. Other construction or industrial operations may also use these systems. If a powered light source is needed where there is no existing, fixed lighting system, or where the fixed lights are inadequate, a high-intensity mobile system is beneficial. 
     These mobile lighting systems typically require substantial electric power because of the powerful lights used. Generators are perhaps most frequently used to provide the needed electrical power, because generators are mobile and can be mounted on the same structural body as the lighting system. Many mobile lighting systems are in common use—for example, the type often seen on remote strip mining sites—rely on generators for power. An external source of electrical power—often referred to as “shore power”—also may be used to provide power to these lighting systems. Some newer mobile lighting systems use LED lights, which use much less power. Such a system might be powered by solar panels. 
     Many of the mobile, high-intensity lighting systems in use have the lights mounted on a boom. Such a boom is typically kept in a roughly horizontal position when the system is not in use or during transport. Such systems are often mounted on trailers, which allow for easy transport of the system. A typical system of the type just described, would be secured in an operating location, perhaps using ground jacks or other means. The boom would then be raised to a roughly vertical position, so that the lights are raised. The power supply would be activated (generator, shore power, or other), and the lights would be turned on. 
     These types of lighting systems are widely used and serve their purposes. Most have a few lights, and a boom of ten to fifteen feet. This type of lighting system is reasonably stable and simple to build and operate. It will effectively light a somewhat small area, and as a result, multiple units of this type are often needed to light a larger area. The need for multiple units increases the cost and complexity of the operation, and might require multiple workers to operate and oversee the lighting systems. In some situations, there may be limited locations that can support a mobile lighting system (e.g., refinery turnarounds, LNG new construction and other massive construction site projects). 
     When there is a need for a great deal of light from a small number of sources, the typical mobile lighting systems do not work well. What is needed is a mobile lighting system with much more lighting capacity positioned in a way that will light a much larger area. To achieve this result, the lighting system needs numerous lights and those lights must be raised to a far greater height than fifteen feet. Lighting towers, 80′ and 100′ or more would provide the coverage needed. Such towers, however, pose numerous challenges. 
     A mobile lighting system with an 80′ and 100′ or longer boom must be capable of storing the boom in more compact form. It is not practical to have a mobile light tower with a 80′ and 100′ or longer boom that is always fully extended. Such a tower could not be moved in the vertical position, and in the horizontal position, such a tower would be unduly long and unwieldy. There is a need for some structure that allows the light tower to be stored in a more compact manner. 
     A light tower of 80′ and 100′ or more with a large number of lights produces a large “sail” area high above its base. The large number of lights results in a large surface area. Wind acting on such a large area can generate very large forces. With a long tower (i.e., 80′ and 100′ or more), these forces can create extremely large torque at their base. There is a need, therefore, to protect such systems from high winds. 
     A light tower of 80′ and 100′ or more requires more precise vertical alignment than a shorter tower. The base for these long towers may need additional supporting structure. Such a tower might also benefit from a precision system for achieving vertical alignment. Some structure may be needed to effectively lock the tower boom into position once it is vertical. 
     The present invention provides these needed features. A telescoping light tower is disclosed with multiple sections housed within one another. In a preferred embodiment, there are four boom sections: the outer, first, or primary boom is 10″ in diameter, the second section is 8″ in diameter, the third section is 7″ in diameter, and the last boom section is 6″ in diameter. These boom sections can be extended to produce a very long lighting tower. Towers of 100′ or more are possible with the present invention, and towers of 60′ or more may benefit, as well. 
     A wind speed sensor using detectors mounted near the lights may be used to detect dangerous high speed wind conditions. When wind speeds are above a preselected set point, the extended boom sections could be automatically lowered to reduce the risk of wind damage. 
     Other safety features are disclosed that ensure the boom sections remain extended while the lighting system is in use. Additional features allow the lifting force to disengage before the boom sections reach their limits in order to protect equipment from overload conditions. Locking mechanisms may be used to secure the main boom in the vertical position for operation and in the horizontal position for transport. 
     In a preferred embodiment, the present invention includes a base; a frame secured to the base; a pivot structure secured to the base and the frame; a primary boom section pivotably connected to the pivot structure; a first extendable boom section positioned within the primary boom section and configured to be extended from and retracted into the primary boom section; a means for pivoting the boom sections about the pivot structure; a means for extending and retracting the first extendable boom section; a means for securing the primary boom section in a vertical position; and, one or more safety features from the following group: a boom extension lock; a boom extension/retraction warning; a boom extension mechanical stop; a high wind speed sensor and automatic retraction system; and an automatic winch deactivation system configured to stop an extension/retraction winch when an extendable boom section is fully extended or fully retracted. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG.  1    shows illustrations of preferred embodiments of the present invention. 
         FIG.  2    is a front perspective drawing of the base and lighting sections of a preferred embodiment of the present invention. 
         FIG.  3    is a perspective view of a telescoping boom section of a preferred embodiment of the present invention. 
         FIG.  4    is a perspective view of the upper boom and light sections a preferred embodiment of the present invention. 
         FIG.  4   a    shows the pivot system of a winch operated preferred embodiment of the present invention. 
         FIG.  5    shows an embodiment of a boom lock for the invention. 
         FIG.  6    is a diagram of a cable and pulley arrangement used m a preferred embodiment of the present invention. 
         FIG.  7    is a diagram of switch and relay components of a preferred embodiment of the present invention. 
         FIG.  8    shows a hydraulically powered pivot system of a preferred embodiment of the present invention. 
         FIG.  9    is a top view showing outriggers of a base of a preferred embodiment of the present invention. 
         FIG.  10    shows an inverted fender skid structure of a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is best described by starting with general illustrations of some preferred embodiments.  FIG.  1    shows of variety of embodiments of the mobile, high intensity, extendable light tower  10 . These embodiments show of variety of different base configurations. In some embodiments, a trailer base  14  is used, having wheels and a hitch that can be connected to some type of towing vehicle. In another embodiment, a flat base  16  is shown which is designed to rest on the ground. Outriggers  18  are shown with some embodiments. A third embodiment includes a skid base  20 , which can be dragged to a location. Each of these embodiments include lights  12  at the upper end of a boom. 
       FIG.  2    shows the primary features of the present invention mounted on a trailer platform. The mobile, high intensity, extendable light tower  10  is shown both in raised and lowered positions. The light section  22  is shown only in the raised position (i.e., it is omitted from the lowered positions to reduce the complexity of the drawing). A number of lights  24  make up the light section  22 . A power cable  26  extends from the light section  22  to the base region of the system. 
     A generator  30  is shown on the base platform in  FIG.  2   . Outriggers  18  are also shown in this figure, and have outrigger ground supports  32 . Stabilizer jacks  34  are mounted to the trailer base and are used to provide a solid foundation for the system. The stabilizer jacks  34  are used to ensure the light tower is vertical when in operation. Several basic trailer components are also shown in this figure, including a front trailer jack  36 , a trailer hitch  38 , trailer electrical cable  39 , trailer lights  40 , a trailer brake system  42 , trailer tires  44 , and fenders  46 . Fender bolts  48  are used to connect the fender  46  to the trailer frame. This allows the fenders to be removed, inverted, and then used as a skid. This arrangement is shown in a later drawing. 
     The extendable booms of the present invention are also shown in  FIG.  2   , though only in retracted position. A primary boom section  50  is shown-it is 10 inches square in this embodiment. Within the primary boom  50  is housed an 8-inch boom  52 , which houses a 7-inch boom  54 , which houses a six-inch boom  56 . This nested-boom structure is explained in more detail below. When stored for transport, the booms rest on a boom support frame  62 , which is secured to the base frame  64 . A boom horizontal cradle lock  58  surrounds the primary boom section in the stored position. A boom horizontal cradle lock pin  60  is used to lock the boom in the horizontal, stored position. 
     A tower pivot post  66  is securely mounted to the trailer frame and to the boom support frame  62 . The boom sections pivot about a boom pivot member  68 . When in the raised position, the booms are secured to the tower pivot post  66  by a boom vertical cradle lock  70  and a boom vertical cradle lock pin  72 . 
     A pivot controller  74  is actuated to begin operation of the pivot winch  76 , which uses a dual cable system  78 . As the pivot winch  76  begins to spool in the cable, the cable goes through the pivot post pulley box  82 , mounted at the lower end of the pivot post  66 . The cable then extends through the primary boom pulley box  84 . When the cable is retracted by the winch  76 , it pulls the lower end of the boom section toward the base of the tower pivot post  66 . When viewed from the side (as in  FIG.  2   ), the booms are rotated counter-clockwise when being raised from horizontal to vertical position. The boom vertical cradle lock  70  and pin  72  are used to secure the boom in the vertical position. 
     A number of safety features may be used to control the final positioning of the boom sections. Boom springs  86  can be used to slow the final positioning of the boom sections. A vertical stop limit switch  88 , paired with a horizontal stop limit switch  90 , can be used to deactivate the winch when the boom has reached the vertical or horizontal position. Winch heaters  92  can be used to warm the winch motor in cold operating conditions. Forklift pockets  94  are shown on the boom support frame  62 . These allow the entire unit to be lifted and moved using a forklift. 
     Once the nested boom sections have been locked in the vertical position, the extendable booms may be raised. This operation begins by using the telescoping controller  96 , which activates the vertical winch  98 . A telescoping warning light  100  is also activated during this operation. A warning alarm or buzzer may also be used to warn any personnel in the area that the light tower is being raised. The process of extending the boom sections is explained in more detail below. 
       FIG.  2    also presents a number of other components found in a preferred embodiment of the invention. A winch control box  108  is shown. A main power switch  114  is shown near the light control box  112 , which contains a lighting contactor  116  a daytime controller  118  and lighting ballast  120 . 
     The light section  22  shown in  FIG.  2    includes a  4 -inch top lighting bracket  122  and a 4-inch bottom lighting bracket  124 . A light electrical connection box  126 , and a wind speed sensor  128  are also shown as part of the light section  22 . A wind speed detector and controller  130  are positioned in the light control box  112 . Finally, a pulley at the top of the 8-inch boom section  132  and a pulley at the top of the 7-inch boom section  134  are also shown in  FIG.  2   . 
       FIG.  3    shows the telescoping boom portion of a preferred embodiment of the present invention. In this embodiment, the length of the individual boom sections is selected to provide the ultimate height needed. Ten foot boom sections will produce a telescoping section of about 40′ when fully extended. Twenty or twenty-five foot boom sections will produce an extended boom height of about 80′ or 100′. The lighting section extends above the boom sections, and the boom sections are mounted on a base, so these two features raise the lights more than the extended length of the boom sections. A typical total height of the invention, for example with twenty foot boom sections would be 80′ -100′. Twenty foot boom sections are a preferred embodiment, providing a total tower height of almost 100′, which is higher than existing products and provides sufficient light for a large area. 
     The boom sections shown in  FIG.  3    are raised to vertical position using the winch and cable process described in connection with  FIG.  2   , above, or using hydraulic lifting, as will be described below. The boom sections could be raised to the vertical position using any suitable means, even through use of an external crane or front-end loader, in the event such external lifting source is needed. Once locked into the vertical position, the boom sections may be extended upward. The present invention may use a winch and cable system or hydraulics to raise and lower the boom sections. Hydraulic stabilization jacks also may be used. The extension/retraction processes can be remote controlled from over 300′ from tower. The stabilization jacks and other components may also be controlled remotely. This capability provides an added layer of safety for operators. 
     To extend the boom sections shown in  FIG.  3   , a telescoping controller  96  is actuated, which powers the vertical extension winch  98  that uses a dual cable system  78  that balances load on the winch drum. Two sets of cables are used in this preferred embodiment, with one on each side of the boom sections. When the boom extension process begins a telescoping warning light  100  is illuminated and a warning horn, alarm, or buzzer is sounded. These features are important because they alert others in the general area that a potentially dangerous operation is in process. Given the heights to which the boom sections may be extended, if the tower were to fall when extended, it could reach persons who are not particularly close to the tower base. Some type of alarm or warning system is preferred, and it is activated any time the boom sections are being extended or retracted. 
     The vertical extension winch  98  is secured to the base section or to the primary boom section  50 , which is a 10″ section in this embodiment. The cable system  78  extends up and down along each boom section. The second boom section  52  is 8″ square in this embodiment. It has a pulley box  142  located near its lower end. This is shown in  FIG.  3   , though in operation, this pulley box would not be visible when the 8″ boom section is retracted. Somewhat similar pulley boxes are located near the lower end of the 7″ boom section  54  and the 6″ boom section  56 . It should be noted that the boom sections may be of different sizes, and the dimensions given here are merely exemplary and not limiting. 
     As the winch  98  is operated, the cable system  78  begins to wrap onto the double winch drum  80 . The cables pass over pulleys near the top of each boom section and then through the pulley boxes like the 8″ boom section pulley box  142  shown in  FIG.  3   . In the preferred embodiment shown, one upper pulley is shown with each of the extending boom sections: an upper pulley on the 8″ boom section  132 , and an upper pulley on the 7″ boom section  134 . In this embodiment, there are two of these pulleys near the top of each extending boom section, though only one can be seen in  FIG.  3   . 
     The cables pull each boom section up and can be configured to produce any desired sequence of boom section extension. The pulley boxes on each boom section can be configured to alter the lifting force generated. If an equal lifting force is applied to each boom section, the smallest boom section (i.e., the 6″ boom section  56  in this embodiment) will be raised first because it weighs less than the larger boom sections. If configured in this way, the boom sections will extend from smallest to largest. This sequence may be altered by configuring the pulley boxes to exert different lifting forces to the different boom sections. It may be preferred, for example, to have the larger boom sections extend first. The chosen extension sequence is not a limitation of the present invention and may be altered to meet the needs or desires of particular applications. 
     The invention uses important safety features in connection with the extension of the boom sections. An alarm or warning system was mentioned above. In addition, a vertical up limit switch  102  is used to disengage the winch when the boom sections are fully extended. This reduces the stress load on the winch. A boom extension lock  104  is used with each boom section, and is activated when the boom section has been fully extended. The extension lock  104  is an electromechanical device in a preferred embodiment, and will be described in more detail in connection with  FIG.  5    below. The device extends a locking cam  154  that prevents the fully-extended boom section from being lowered. This locking system is activated when each boom reaches its intended height, and is deactivated before the boom sections are retracted. 
       FIG.  3    also shows the wind speed sensor  128  and the wind speed detector/controller  130 , which is set to 40 mph in this embodiment. The sensor  128  feeds a signal to the detector/controller  130 . If the detected speed reaches a pre-selected set point (e.g., 40 mph), the boom sections are automatically retracted to prevent wind damage to the lighting system. A wind speed sensor cable  148  is shown as is a wind speed control cable  150 , where the latter cable is shown in connection with the winch  98 . This system is connected through the control system for the telescoping operations. In addition, the wind speed components of the present invention may be configured to sound a high-wind warning at a set point somewhat below the point at which automatic retraction is activated. This would warn operators that high winds are occurring and that the system may be retracted due to such winds. This would allow workers time to secure any critical operations before they lose lighting. 
       FIG.  3    also shows a group of mechanically operated limit switches. The up limit switch  144  is used to stop the winch  98  when the boom sections have been fully extended. The down limit switch  146  stops the winch when the boom sections have been fully retracted. Wiring cables  152  for these limits switches and for the alarm/warning system are shown collectively in  FIG.  3   . Mechanical stops are also shown in  FIG.  3    for each boom section. The mechanical stops are a redundant form of protection to ensure the boom sections cannot be extended beyond the intended range. 
     The mechanical stops on each boom section engage with a mechanical stop clip on each larger-sized boom section. The 8″ boom mechanical stop  162  would be physically stopped by the 10″ boom section mechanical clip  168 . The 7″ boom mechanical stop  164  would engage with the 8″ boom section mechanical clip  170 . And finally, the 6″ boom mechanical stop  166  would engage the 7″ boom section mechanical clip  172 . 
     Thus, the preferred embodiment shown in  FIG.  3    shows key safety features of the present invention: the operation alarm/warning system, the high-wind protection, the limit switches to disengage and thus protect the winch, boom extension locks, and the redundant mechanical stops. These features combine to make the invention safe, while also allowing for a telescoping lighting system that can reach heights of 100′ or more. Not every safety system shown must be used, but all provide certain types of protection. In the most preferred embodiment, all of the shown safety features would be used. 
       FIG.  4    shows the upper ends of the boom sections and the light section  22  of the invention. In this embodiment, the lights  24  consist of eight lights mounted on a 4″ top lighting bracket  122  and eight additional lights on a 4″ lower lighting bracket  124 . A light electric connection box  126  is shown and would house the connections from the main power cable  26  to each light  24 . The lighting brackets  122 ,  124  are mounted above the 6″ boom section, and the wind speed sensor  128  is shown at the top of the lighting tower. The wind sensor  128  may be mounted in any position where it will be exposed to full wind conditions. It should not be mounted, however, where the large lights  24  are capable of blocking wind from reaching the sensor  128 . 
     Several of the features described in connection with  FIG.  3    are shown again in  FIG.  4   . These include the pulley box  142  of the 8″ boom section  52 . The primary 10″ boom pulley box  84 , the 8″ boom section upper pulley  132 , and the 7″ boom section upper pulley  134  are shown. When the winch  98  (not shown in  FIG.  4   ) is operated, the cable system  78  goes through the 10″ boom pulley box  84 , which is located near the top of the 10″ boom section. The cable system  78  then extends down to the 8″ boom section pulley box  142 , which is located near the lower end of the 8″ boom section. In this manner, when the cable system  78  is retracted by the winch  98 , the 8″ boom section  52  is lifted upward. Similar processes result in the lifting of the 7″ boom section  54  and the 6″ boom section  56 . Note that no pulleys are required at the top of the 6″ boom section. 
       FIG.  4    also shows the up and down limit switches and the mechanical stop features described above in connection with  FIG.  3   . The boom extension lock  104  is also shown here. These features serve the same purposes and work in the same way described above. It should be noted that the present invention could use more than four telescoping boom sections. Adding more boom sections will add more weight and more stress to the winch, cable, and pulleys. A four boom section system is preferred because it provides a good balance between working height and typical component capacities. 
     For example, in the embodiment shown in  FIGS.  3  and  4   , a 3,000 pound capacity winch may be used. When a block and tackle arrangement for the 8″ boom pulley box  142  is used, the total lifting power of the winch can be increased. In a preferred embodiment, the lifting power is tripled to 9,000 pounds. Standard ¾″ cable may be used, which typically has a working tensile strength of about 15,000 pounds. These components have been shown to work with 20′ long boom sections of 10″, 8″, 7″ and 6″, as shown in these figures. Adding an additional boom section (e.g., a 5″ section) would probably still fall within the working capacities of these components. Such variations are within the scope of the present invention. 
       FIG.  4   a    shows a more close-up view of the transitioning of the boom section  28  from the horizontal, transport or storage position to the vertical, operating position. The boom section  28  is stored in a roughly horizontal position, and is secured using clamps, straps, locking pin and cradle (as shown in  FIG.  2   ), or other appropriate means. In the horizontal position, with the extendable boom sections all retracted, the invention is typically about 10′ in height, which allows it to be towed behind a vehicle without creating any special clearance concerns. This positioning is also stable and reduces wind resistance when transporting the unit. 
     Once the unit is in position for use, whatever means were used to secure it in the horizontal position are removed or disengaged, and the boom section  28  is then raised to the vertical position. It is then secured in the vertical position using clamps, straps, locking pin and cradle (as shown in  FIG.  2   ), or other appropriate means. This operation is described above in connection with  FIG.  2   . 
       FIG.  5    shows the operation of a preferred embodiment of the boom extension lock  104 . In this embodiment, an electro-mechanical mechanism is used. A solenoid  180 , having a coil  182  and a plunger  184 , is used to move the boom locking cam  154 . A bias spring  186  is used to bias the mechanism to the engaged position. In  FIG.  5   , the mechanism is shown mounted on the 10″ primary boom section  50 , so that when used, it locks the 8″ boom section in the fully extended position. 
     The bias spring  186  pulls the locking cam  154  inward, that is, toward the interior of the 10″ boom section  50 . The solenoid  180 , when powered on, will pull the plunger  184 , and thus the locking cam  186  outward. In other words, to hold the locking cam  186  in the disengaged position (i.e., the position shown in  FIG.  5   ), the solenoid must be powered on. The mechanism could easily be designed in the reverse of the configuration shown in  FIG.  5   —that is, with the bias spring tending to keep the locking cam  154  disengaged and the solenoid  180  being powered on to engage the lock. The arrangement shown in  FIG.  5    is preferred because it is a fail-safe configuration. Upon a loss of power to the solenoid, the locking cam  154  will engage, or at least will remain pressed against the outer surf ace of the inner boom section. In this condition, the boom extension lock  104 , will automatically lock a fully extended boom section, and will only disengage when power is supplied to the solenoid  180 . When the inner boom section is fully extended, and the locking cam  154  is extended inwardly, the cam  154  will block the boom section from being retracted, or from free-falling. The engaged position of the locking cam  154  is shown in dashed lines on  FIG.  5   . 
     During normal operations, the boom extension lock  104  operates automatically in preferred embodiments. The solenoid  180  is powered on as the boom sections are raised. When a particular boom section reaches its fully extended position, a limit switch is actuated, and this switch then results in the power being removed from the solenoid  180 . The locking cam  154  is then extended inwardly by the force of the bias spring  186 , and locks the boom section in the fully extended position. When the boom sections are retracted, the same system will automatically supply power to the solenoid  180 , causing the locking cam  154  to be pulled outward, which allows the boom sections to be retracted (i.e., lowered). 
       FIG.  6    shows one configuration for the pulley box  142 . In this embodiment, one line of the dual cable system  78  passes over 6″ pulley  190 , then 5″ pulley  192 , 4″pulley  194 , and then around 6′ lower pulley  196 . The cable then passed over 4″ guide pulley  198 , under 5″ upper pulley  200 , and around 6″ upper pulley  202 . The cable then goes over 4″ lower pulley  204 , around 6″ lower pulley  206  and over 4″ guide pulley  208  before leaving the pulley box  142  toward the upper pulley on the 8″ boom section  132 . This arrangement creates a block-and-tackle configuration with a mechanical advantage of four. Different arrangements can be used to either increase or decrease the mechanical advantage. With a lower mechanical advantage, the winch will extend and retract the boom sections more quickly, but greater winch power will be needed. The configuration shown in  FIG.  6    provides sufficient mechanical advantage for the preferred embodiments described above. 
     A hydraulic-powered embodiment is shown in  FIG.  7   . A hydraulic fluid tank  212  supplies fluid to a hydraulic pump  216 , which sends pressurized fluid to the hydraulic cylinders. A control station  214  is used to actuate the appropriate cylinders. A pivot cylinder  218  is used to move the boom sections from horizontal to vertical position and vice versa. Once the boom sections are locked into vertical position, one or more telescoping cylinders  222  may be used to extend and retract the boom sections. Only one telescoping cylinder is shown in FIG.  7 , but there may be separate cylinders for each of the extendable boom sections. In addition, the stabilizer jacks  34  (not shown in  FIG.  7   ) may also be powered by the hydraulic system. 
     A hybrid cable/hydraulic system is also possible for the invention. The hydraulic pivot cylinder  218  could be used to pivot the boom sections to and from the vertical position, and a winch system like that described above could be used to extend and retract the boom sections. Or hydraulics could be used to extend and retract the boom sections, while a winch is used to pivot the boom sections. These operations may be controlled from a remote location using any conventional type of remote control technology. 
     In addition, a lighting tower in accordance with the present invention could be controlled and operated from a location completely remote from the operating site using Internet, satellite transmission, or other means of communication over long distances. This capability would allow for the present invention to be used in areas that may not be accessible or hospitable to workers. Such locations might include radioactive sites or sites in extreme cold. The present invention could be paired with a remotely steerable unit to move the light tower into position, and then the control systems described herein could be used to operate the light system. All such configurations are within the scope of the present invention. 
       FIG.  8    shows a top view of a trailer base  14  with base frame  64 , but without the upper components. Outriggers  18  are shown with their respective ground supports  32 . Stabilizer jacks  34  are used to secure the base and to ensure the boom sections (not shown) are in vertical alignment before being extended. A trailer hitch  38  and the fenders  46  are also shown. 
     The reversible fenders  46  of the present invention are shown in more detail in  FIG.  9   . The fender bolts  48  are used to secure the fenders to the base frame  64  (not shown). This allows the removal of the fenders  46 , which may be turned over and positioned below the wheels. The reversed fenders  46  and then reattached using the bolts  48 , and now serve as a skid, allowed the base to be pulled over flat ground where the wheels might become stuck. 
     The final drawing,  FIG.  10   , shows a series of protective screen guards. The winch guard  230  covers the working area of the lower winch assembly and protects personnel in the event a cable breaks or otherwise becomes free from the winch. A pivot assembly guard covers the areas of the boom sections  28  that pivot when the sections are moved from horizontal to vertical and back. Finally, a boom guard  234  covers the winch and cables on the exposed area of the boom sections. Similar guards may be used with the hydraulic-powered embodiments, with guards positioned around the key hydraulic components (not shown in  FIG.  10   .). 
     The preceding description is provided to illustrate certain preferred embodiments of the present invention. This description is not limiting and persons with skill in the art will recognize the existence of other variations on the structures and methods described above. All such variations, to the extent they are consistent with the preceding description and the following claims, are intended to be within the scope of the invention set forth in this patent.