Abstract:
A towable power plant is disclosed capable of supplying visible light for use at a worksite and at least on other power source. The power source may generate compressed air, electricity, or may pump water or a hydraulic fluid. The light tower may be coupled to the drawbar of an existing towable power plant.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of towable power plant and more particularly to a power plant capable of generating compressed air and worksite illumination. 
     BACKGROUND OF THE INVENTION 
     Trailerable power plants are used as power sources at remote locations. Gas or diesel engines are usually mounted upon a trailer frame, together with their accessory units such as cooling or radiator systems, fuel tanks, and associated electrical systems, and are used to drive a single power source, such as, for example, an electrical generator, hydraulic pump, air compressor, or water pump. They are most commonly used in civil construction applications such as road or building construction projects where regular utility services may not be readily available. Examples of such applications include trailerable light towers used for illumination of road construction projects where connection to electrical power lines would be difficult or impossible to achieve. Another example would be an air compressor air for a pneumatic jack hammer. 
     Many road construction projects are typically done a night to limit the impact on commuters traveling to and from work. Nighttime road work projects such as repairing or replacing pipes under a roadway require the contractor to tow an air compressor and a light tower to the worksite. The air compressor is used as a source of compressed air for a pneumatic jackhammer and the light tower is used to illuminate the worksite. A problem with separate towable units for compressed air and lights occurs on smaller jobs where a single person could perform the task, but the contractor is required to send two workers, one to drive each of the tow vehicles. 
     Towable light towers are typically used to light a large worksite and the lights run directly off of the engine. A drawback to this type of system is that a user must start the engine in order to get light to illuminate a worksite. 
     Accordingly what is needed is a single towable engine housing that is capable of generating compressed air and work sight illumination. It is also desirable to have a light tower kit that may be added to an existing towable power unit. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, a towable air compressor and light tower unit is disclosed that is mounted to a trailer with wheels and a hitch. A user may tow this single unit to a job site and provide illumination of the work site and compressed air for powering a jackhammer or other tool. 
     In accordance with another aspect of the present invention, a light tower kit is disclosed that can be secured to an existing towable air compressor, electric generator, hydraulic pump, or water pump power plant to add the feature of worksite illumination. 
     The above and other objects, feature, and advantages of the present invention will be apparent in the following detailed description thereof when read in conjunction with the appended drawings wherein the same reference numerals denote the same or similar parts throughout the several views. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a towable power plant consistent with the present invention. 
     FIG. 2 is a block diagram of a towable power plant consistent with the present invention. 
     FIG. 3 is an exploded view of a light tower consistent with the present invention. 
     FIG. 4 is an electrical block diagram of a light tower coupleable to the power plant of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The general arrangement of the elements is shown most clearly in FIG.  1 . This shows a towable power plant  100  including a frame  102  with a drawbar  104  and a hitch  106 . A pair of wheels  108  is coupled to the frame  102  either with or without suspension. An enclosure  110  houses an engine  202 . The engine  202  may be fixedly secured to the frame  102 . A light tower  300  may be coupled to the drawbar  104 . The light tower  300  may be coupled to the drawbar  104  with mechanical fasteners, by welding or any other process. A portion of the light tower  300  is moveable between a towable position and a working position. In the towable position, the moveable portion of the light tower may be secured to a coupling  144  secured to the enclosure  110 . In the working position the light tower is preferably coupled only to the frame  102  and does not contact the housing  110 . 
     As shown in FIG. 2, the engine  202  is coupled to a starter  204 , an alternator  206 , and an air compressor  208 . Alternatively, the engine  202  may drive an electric generator, a water pump, or a hydraulic pump. The engine  202  may use any fuel including, but not limited to, gasoline, diesel, and natural gas. The compressor  208  may be coupled to a storage tank  210  in known fashion. The output of the compressor  208  or the tank  210  may be used to drive pneumatic tools such as a jackhammer. The alternator  206  may be used to recharge an energy storage device, for example a battery  212 . The battery  212  may be coupled to the starter  204  through a series of switches or actuators and a relay coil  220  that may be arranged in a variety of different ways. An ignition switch  214  may be manually operable with a key or any other means to make or break electrical connection with the battery  212 . The ignition switch is preferably a momentary switch. An optional air pressure switch  216  may also be used to make or break electrical connection with the battery  212 . The air switch may break connection with the battery if the air pressure in the tank  210  exceeds a predetermined value. A manually operable switch, for example a toggle switch  218  may also be used to make or break electrical connection with the battery  212 . The toggle switch is preferably a maintained switch. 
     A socket  230  may also be electrically coupled to the battery  212  through a fuse  234  and a relay contact  232 . The relay contact may be used to control the on/off status of the lamp  320  and may have an actuator that extends through an opening in the enclosure  110 . The socket may be mechanically coupled to the housing  110  of the towable power plant  100 . 
     FIG. 3 shows the light tower assembly  300 . The light tower assembly includes a first support member  302  rotatably coupled to a second support member  304  about a pivot pin  306 . The first member  302  is moveable between a towable position (as shown in FIG. 3) and a working position (as shown in FIG.  1 ). The second member  304  is coupleable to a draw bar  104  of a towable trailer with mechanical fasteners  308  and clamps  310 . Alternative fastening methods including welding shall be considered part of the present invention. The first member  302  may be mechanically secured to the second member  304  in the working position with a pin  332 . 
     A lamp  320 , for example a 100-watt incandescent lamp, may be coupled to a light-mounting bracket  322  that is couple to a light-rotating shaft  324 . Preferably, a plurality of lamp may be coupled to the light-mounting bracket  322 . The light-rotating shaft  324  is capable of being manually rotated about the longitudinal axis of the first member  302  with a handle  326 . The light-rotating shaft  324  may extend through a series of aligned opening in plates extending from the first member  302 . Knob  340  may be used to resist rotational motion of the shaft  324 . A retainer  342  and collar  344  may be used to prevent removal of the shaft  324  along the longitudinal axis of support member  302 . 
     A winch  326  with a handle  348  is coupled to the second member  304  with suitable fasteners or by welding. A first end of a cable  350  may be connected to the winch  326  and then extends around a guide or pulley  328  and the second end is coupled to the first member  302  near an end opposite the lamp  320 . The pulley  328  may be secured to the second member  304  with a bracket  330 . A lanyard  334  may be used to secure locking pin  30  and a leaf spring  336  may be used to aid in lowering upper support  302  from vertical position. A wire clip  338  may be used to secure cable assembly to upper support  302 . 
     FIG. 4 shows a wiring assembly  400  with a plug  402  coupled at a first end of a length of cable  404  and at least one lamp electrically coupled to a second end. Connectors  406  may be used to allow for removal of the lamp. The connector  406  may be coupled to lamp  320 . A portion of the wiring assembly  400  may be secured to the outside of the first member  302  or alternatively it has to be housed inside of the first member. The plug  402  is matable with the socket  230 . 
     Alternatively a wiring assembly  400  may have alligator style clips secured at the first end in place of the plug  402  to allow for connection to the positive terminal of battery  212  and the negative terminal of the battery or a convenient grounding point. The cable  404  may enter the enclosure through an existing opening or through one of the enclosure doors. 
     It should be understood that, while the present invention has been described in detail herein, the invention can be embodied otherwise without departing from the principles thereof, and such other embodiments are meant to come within the scope of the present invention as defined in the following claims: