Abstract:
A load warning system for use with a vehicle having a load-support portion, a frame, and a vehicle-support portion movably coupled to the frame. The system has an engagement portion mountable to the vehicle-support portion or the frame and is movable therewith as a unit. A load indicator is mountable to the other one of the vehicle-support portion or the frame, and is spaced apart from the engagement portion when in a first position. The load indicator moves to a second position and engages the engagement portion when the frame moves a selected distance in response to the load applied to the load-support portion. The load indicator provides a signal upon being moved to the second position. A warning indicator is coupled to the load indicator and provides an improper load warning to a user in response to the signal from the load indicator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims (37 C.F.R. § 1.172(b)).

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]     The present application claims priority from U.S. Provisional Patent Application No. 60/459,699, filed on Apr. 1, 2003, which is hereby incorporated in its entirety by reference thereto. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention is directed to load warning systems, and more particularly to load warning systems for vehicles.  
       BACKGROUND  
       [0003]     Vehicles, such as trucks, typically have maximum load ratings set by the vehicle manufacturer. Many vehicles have payload areas that can be loaded with a payload that could exceed the maximum load rating. The payload areas can also be improperly loaded with a payload even though the payload doesn&#39;t exceed the maximum load rating for the vehicle. For example, a payload below the maximum load rating could be located too far to one side or too far to the rear, thereby changing the handling or steering characteristics of the vehicle. It is highly desirable to provide a warning system that indicates when a vehicle is improperly loaded.  
         [0004]     Prior systems have been designed to accurately measure the payload weight or axle weight. Most of these systems use load cells to support the weight and provide an electrical signal indicative of the weight. Some systems have relied on the deflection of the vehicle&#39;s suspension to provide an indication of load. As an example, U.S. Pat. No. 3,531,766 to Henzel discloses such a sensing system for overload indication. U.S. Pat. Nos. 4,789,033; 5,522,468; and 6,259,041 B1 to Dohrmann show various systems that translate suspension travel into motion that can be measured. The sensor output is sent to a display unit that gives an indication of weight. These prior art systems, while detecting weight, have limitations in determining or detecting improper load conditions in a vehicle.  
       SUMMARY  
       [0005]     The present invention provides a load warning system that overcomes drawbacks experienced in the prior art and that provides additional benefits. Under one aspect of the invention, a load warning system is provided for use with a vehicle. The vehicle has a load-support portion adapted to receive a load thereon. A first portion of the vehicle, such as a frame, is coupled to the load-support portion. A second portion of the vehicle, such as an axle or suspension system, is movable relative to the first portion upon application of the load onto the load-support portion. The load warning system has an engagement portion mountable to and movable with the one of the first portion or second portion of the vehicle as a unit.  
         [0006]     A load indicator is mountable to the other one of the first portion or second portion of the vehicle. The load indicator is configured to be spaced apart from the engagement portion and to be in a first position when the load on the load-support portion is less than a maximum load. The load indicator is also configured to engage the engagement portion and move to a second position when the load on the load-support portion is greater than a maximum load. The load indicator provides a signal upon being moved to the second position. A warning indicator is coupled to the load indicator to receive the signal and to provide an overload warning to a user upon receiving the signal.  
         [0007]     Under another aspect of the invention, a load warning system has an engagement portion movable with a vechicle&#39;s frame or a vehicle-support portion. A load indicator is coupled to the other one of the vehicle-support portion or the frame. The load indicator is spaced apart from the engagement portion when in a first position. The load indicator is configured to move to a second position and engage the engagement portion when the load applied to the load-support portion exceeds a first maximum load. The load indicator is also configured to move to the second position and engage the engagement portion when the load applied to the load-support portion exceeds a second maximum load less than the first maximum load and when the load is positioned rearward of the load indicator or the engagement portion. A warning indicator is coupled to the load indicator and configured to provide an overload warning to a user in response to the load indicator moving to the second position.  
         [0008]     Under another aspect of the invention, a load warning system has an engagement portion movable with the vehicle-support portion or the frame of a vehicle. A load indicator is coupled to the other one of the vehicle-support portion or the frame. The load indicator is spaced apart from the engagement portion when in a first position. The load indicator is also configured to move to a second position and engage the engagement portion when the frame moves a selected distance relative to the vehicle-support portion in response to the load being applied to the load-support portion. The load support portion has a switch assembly and a trigger coupled to the switch assembly. The trigger is resiliently bendable against the engagement member after the load indicator is moved to the second position. A warning indicator is coupled to the load indicator and configured to provide an overload warning to a user in response to the load indicator moving to the second position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a side elevation view of a vehicle with a load warning system in accordance with an embodiment of the present invention.  
         [0010]      FIG. 2  is an enlarged partial schematic plan view of a load-support portion of the vehicle of  FIG. 1  with a load thereon.  
         [0011]      FIG. 3  is an enlarged top isometric view of the load warning system mounted on the vehicle of  FIG. 1 .  
         [0012]      FIG. 4  is a partially exploded enlarged isometric view of components of the load warning system of  FIG. 3  shown removed from the vehicle.  
         [0013]      FIG. 5  is an enlarged isometric view of an alternate embodiment of the load warning system mountable on the vehicle of  FIG. 1 .  
         [0014]      FIG. 6  is an enlarged bottom isometric view of components of an alternate embodiment of the load warning system on the vehicle of  FIG. 1 .  
         [0015]      FIG. 7  is a schematic plan view of the load warning system on the vehicle of  FIG. 1  showing wire routing along the vehicle.  
         [0016]      FIG. 8  is an enlarged plan view of a relay assembly of the electrical components of the load warning system of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0017]     The following discussion provides a general overview of the orientation and structure of the load warning system and associated components of one or more embodiments of the present invention. Throughout this disclosure, embodiments of the system are presented to display the robust nature of the device.  FIG. 1  is a side elevation view of a vehicle  10  that includes a load warning system  12  in accordance with an embodiment of the invention. Details of embodiments of the load warning system  12  are provided below. The load warning system  12  provides an effective, simple and low-cost system to assist in maintaining safe loading conditions of the vehicle  10 .  
         [0018]     The vehicle  10  in the illustrated embodiment of  FIG. 1  is a truck, such as a pickup or flatbed truck, having a bed  16  that defines a load support area. The bed  16  is mounted on a frame  17  of the vehicle, and the frame is coupled to axles  18  and wheels  19  in a conventional manner via a suspension system  20 . The suspension system  20  allows the rear axle  18  and the bed  16  to move relative to each other, for example, when a load  14  is placed in the bed  16  or during the operation of the vehicle. When the load  14  is placed in the bed  16 , the weight of the load compresses the suspension system  20 , thereby moving the frame  17  relative to the rear axle  18 . The heavier the load  14 , the more the suspension system  20  will be compressed and the farther the bed  16  will move relative to the rear axle  18 .  
         [0019]     The load warning system  12  is configured to provide a warning signal to a user when the weight or the position of the load  14  in the bed  16  is sufficient to compress the suspension system  20  and move the frame  17  beyond a certain distance relative to the rear axle  18 . The load warning system  12  is configured to provide a warning signal to a user when the weight of the load  14  exceeds a maximum weight, regardless of the load&#39;s position in the bed. The load warning system  12  is also configured to be activated if a certain load  14 , which weights less than the maximum weight rated for the vehicle, is placed toward the rear of the bed  16 . The load warning system  12  can also be configured to be activated if a certain load  14  less than the rated maximum weight is placed too far to one side of the bed  16 . The load warning system  10  is also configured so it is less sensitive to weight that is placed in the cab of the truck, such as when a driver gets into a vehicle after it is loaded.  
         [0020]      FIG. 2  is a schematic plan view showing the load  14  in the bed  16  of the vehicle  10  of  FIG. 1 . The load  14  can be distributed in the bed  16  in a variety of positions relative to the rear axle  18  of the vehicle  10 . The position of the load  14  in the bed  16  can determine the extent to which the suspension system  20  is compressed and the rear portion of the frame  17  is moved relative to the rear axle  18 . When the load  14  is directly over the rear axle  18  or rearward of the axle, the suspension system  20  will be compressed more and the frame  17  will move a greater distance relative to the rear axle than when the same load is in the forwardmost position in the bed  16 . The load warning system  12  provides a warning signal when the load causes the frame  17  to move vertically or rotationally beyond a selected distance relative to the rear axle  18 . The load warning system  12  could also be used in conjunction with other portions of the vehicle, such as the vehicle&#39;s front axle, to detect either underloading or overloading conditions based on the movement of the vehicle&#39;s frame  17  relative to a selected structure coupled to the suspension system  20 .  
         [0021]      FIG. 3  is an enlarged top isometric view of the load warning system  12  shown installed on the vehicle  10  of  FIG. 1  in accordance with one embodiment of the present invention.  FIG. 4  is a partially exploded, enlarged isometric view of the components of the load warning system of  FIG. 3  shown removed from the vehicle. The load warning system  12  of the illustrated embodiment includes a frame bracket  22  that mounts with conventional fasteners to the frame  17  of the vehicle  10 . In the illustrated embodiment, the frame bracket  22  is mounted to the frame  17  above and rearward of the rear axle  18 . The frame bracket  22  is bolted or otherwise securely mounted to the frame  17  so the frame bracket moves with the frame as a unit. The illustrated frame bracket  22  extends in a cantilevered manner from the frame  17 .  
         [0022]     A switch assembly  28  is adjustably connected to a free end  26  of the frame bracket  22 . The frame bracket  22  is shaped and sized to securely support the switch assembly  28  at a selected location and orientation relative to the rear axle  18 . In the illustrated embodiment, the switch assembly  28  is positioned rearward of the rear axle  18 . The shape and size required for the frame bracket  22  may be affected by the make and model of the vehicle  10  to which the load warning system  12  is being installed. As an example, the frame bracket  22  shown in  FIGS. 3 and 4  is shaped and sized for use on a truck manufactured by Ford, namely, a truck having the F34 cab chassis. In an alternate embodiment shown in  FIG. 5 , the frame bracket  22  is shaped and sized for use on GMC trucks. In other embodiments, different shapes and sizes of frame brackets  22  can be used with other vehicles. In yet other embodiments, the frame bracket  22  may be an integral component of the switch assembly  28 .  
         [0023]     As best seen in  FIGS. 3-5 , the switch assembly  28  includes a sealed housing  30  connected to a mounting plate  31 , and the mounting plate is fastened to the frame bracket  22 . The sealed housing  30  contains a microswitch  32  movable between a normal inactive position and an activated position. The switch assembly  28  has a flexible trigger member  34  connected to the microswitch  32  and sealably coupled to the housing  30  so as to provide a fully protected environment for the microswitch. The microswitch  32  is moved from the normal, inactive position to the activated position by moving the trigger member  34  in any direction perpendicular to the trigger member&#39;s longitudinal axis.  
         [0024]     The microswitch  32  in one embodiment is configured so the microswitch is open when in the normal, inactive position and closed when in the activated position. In this configuration, the switch assembly  28  draws no power when it is monitoring for overload condition. In the illustrated embodiment, the overload switch assembly  28  is a water-resistant assembly, such as the SWM  43  or  44  switch assembly manufactured by Precor, Inc. of Boise, Id. In alternate embodiments, other switch assemblies  28  can be used, including switch assemblies similar to the Precor switch assembly wired to be either in the “normally open” or “normally closed” position.  
         [0025]     The mounting plate  31  extends from the sealed housing  30  and has a pair of apertures  36  that receive fasteners to connect to the free end  26  of the frame bracket  22 . The free end  26  of the frame bracket  22  has corresponding receiving apertures  38  that align with the apertures  36  in the mounting plate  31 . In the embodiment illustrated in  FIGS. 3 and 4 , the lower receiving aperture  38  in the frame bracket  22  is an elongated, arcuate slot that allows for adjustment of the angular orientation of the mounting bracket  31 , and thus the switch assembly  28  relative to the frame  17 .  
         [0026]     In an alternate embodiment illustrated in  FIG. 5 , the frame bracket  22  is an L-shaped bracket with an arcuate-shaped upper aperture  38  that allows for the positional adjustment of the switch assembly  28 . The position of the switch assembly  28  and the trigger member  34  can be adjusted as needed upon installation, maintenance, or calibration of the load warning system  12 . In other embodiments, the switch assembly  28  can be adjustably connected to the frame bracket  22  in other manners that allow for angular or positional adjustment of the switch assembly relative to the frame bracket.  
         [0027]     Once the switch assembly  28  is in the desired position relative to the frame bracket  22 , the fasteners are securely tightened so as to hold the switch assembly in the selected position. The secured frame bracket  22  and the switch assembly  28  will move with the frame&#39;s cross member  24  as a unit relative to the rear axle  18 , such as when the load  14  ( FIG. 1 ) is placed in the bed  16  and the suspension system  20  is compressed.  
         [0028]      FIG. 6  is a bottom isometric view of an embodiment of components of the load warning system  12  configured for a selected vehicle configuration. The load warning system  12  includes a second bracket  40  mounted to the rear axle  18  in a position forwardly adjacent to and spaced apart from the trigger member  34 . In the illustrated embodiment, the bracket  40  is securely bolted at one end to a bell housing  42  of the rear axle  18  and positioned below the trigger member  34  by a selected distance. Accordingly, the bracket  40  moves with the rear axle  18  as a unit.  
         [0029]     The bracket  40  is cantilevered such that the bracket&#39;s free end provides an engagement portion  44  below the trigger member  34  ( FIG. 6 ). The engagement portion  44  is positioned so the trigger member  34  presses against the engagement portion when the suspension system  20  is compressed and the frame  17  is moved beyond a selected distance relative to the rear axle  18 . When the trigger member  34  is pressed against the engagement portion  44 , the trigger member moves the microswitch  32  within the sealed housing  30  from the normal, inactive position to the activated position. Upon moving the microswitch  32  to the active position, a signal is generated that indicates a warning condition.  
         [0030]     Operation of the switch assembly  28  is demonstrated when a load  14  ( FIG. 2 ) is put into the bed  16  ( FIG. 2 ) of the vehicle  10  ( FIG. 2 ). The suspension system  20  ( FIG. 2 ) will be compressed so that the cross member  24  and the switch assembly  28  move as a unit downwardly relative to the rear axle  18  and the bracket  40 . When the weight and/or position of the load  14  in the bed  16  is such that the trigger member  34  moves toward the bracket&#39;s engagement portion  44  but does not press against it, the microswitch  32  in the switch assembly  28  remains in the normal, inactive position so a warning signal is not generated.  
         [0031]     When a load  14  in the bed  16  ( FIG. 2 ) exceeds a maximum weight rated for the vehicle  10 , and the load is generally centered in the bed forward of the rear axle  18 , the load causes the suspension system  20  ( FIG. 2 ) to compress substantially vertically. As the suspension system  20  compresses, the trigger member  34  presses against the bracket&#39;s engagement portion  44 , and the microswitch  32  is moved to the activated position, thereby indicating an overload condition. When a load  14  is placed in the bed  16  directly over the rear axle  18 , the load can compress the suspension system  20  so the trigger mechanism  34  engages the bracket&#39;s engagement portion  44  to indicate an improper load condition, even though the load weighs less than the maximum weight rated for the vehicle.  
         [0032]     When a load  14  is placed in the bed  16  behind the rear axle  18 , the load will compress the suspension system  20  vertically and also cause the bed to slightly rotate about an axis of rotation generally close to the rear axle. As the bed rotates, the rear end of the bed drops and the front end of the vehicle  10  can be raised. As the bed  16  rotates relative to the rear axle  18  past a certain distance, it causes the trigger member  34  to engage the bracket&#39;s engagement portion  44 . Such rotational motion will often occur when the load  14  is less than the maximum weight limit rated for the vehicle. In one embodiment, a load that is approximately 70% of the rated maximum load for the vehicle can activate the load warning system  12  and provide the warning of an improper load condition. Therefore, the load warning system  12  provides a warning when the load exceeds a rated maximum weight or when the weight and position of the load in the bed causes an undesirable loading condition even though the load is below the rated maximum load.  
         [0033]     After the trigger member  34  has moved the microswitch  32  to the activated position, the microswitch will remain in the activated position until the load  14  ( FIG. 2 ) is adjusted or reduced so the switch assembly  28  moves upwardly until the trigger member  34  is lifted out of engagement with the engagement portion  44  of the bracket  40 . The microswitch  32  and the trigger member  34  are biased or otherwise urged toward the normal, inactive position. After the trigger member  34  is lifted from the engagement portion  44 , the microswitch  32  returns to the normal, inactive position.  
         [0034]     In the illustrated embodiments, the switch assembly  28  is activated by engaging the bracket  40 . In alternate embodiments for use on selected vehicles, the switch assembly  28  may be configured and positioned adjacent to another structure on the vehicle  10 , so that the trigger member  34  will move into engagement with that structure when a load is applied to the vehicle. The trigger member  34  will then trip the microswitch  32  so as to generate a warning signal indicating the improper load condition.  
         [0035]     In another alternate embodiment, the switch assembly  28  may be mounted at another location on the vehicle  10  such that the frame  17  will move relative to the other location when a load  14  is applied to the vehicle. For example, the switch assembly  28  could be mounted to the front portion of the vehicle&#39;s frame  17  adjacent to the front axle, so the trigger member  34  is below an engagement structure. If the vehicle  10  is loaded such that the front of the vehicle&#39;s frame  17  is lifted upwardly relative to the front axle, the upward movement of the frame will bring the trigger member  34  into engagement with the engagement portion  44  of the bracket  40 , thereby moving the microswitch  32  to the activated position to indicate an overload or underload configuration. Accordingly, the load warning system  12  is very effective when applying a load  14  to the bed  16  of a vehicle  10 , as well as when other loads are applied to the vehicle&#39;s frame  17 , such as via a trailer or the like.  
         [0036]     As best seen in  FIGS. 5 and 6 , the trigger member  34  is an elongated flexible member that can resiliently bend when pressed with sufficient force against the bracket  40 . The trigger member  34  of the illustrated embodiment is an elongated, tightly wound coil spring coupled to the microswitch  32 . The microswitch  32  has a very small dead band (i.e., the range of motion before the microswitch moves to the activated position), so that the microswitch can be moved to the activated position when a fairly small force is exerted against the trigger member  34 .  
         [0037]     The flexible trigger member  34  has sufficient stiffness so it will not substantially bend or deflect before the microswitch  32  is moved to the activated position. If, however, the movement of the vehicle&#39;s frame  17  relative to the rear axle  18  is extreme, so that the trigger member  34  is pressed hard against the bracket&#39;s engagement portion  44 , the trigger member will resiliently bend so as to prevent extreme forces being applied directly to the microswitch  32 . Further, when the vehicle  10  ( FIG. 2 ) is in operation and encounters significant impact to the suspension system  20  ( FIG. 2 ), such as by hitting a large bump or pot hole, the flexible trigger member  34  can hit and bend against the engagement portion  44  and then return to its original position, thereby protecting the switch assembly  28  from damage. Accordingly, the switch assembly  28  is a simple, rugged, and weather-resistant assembly.  
         [0038]     As best seen in  FIGS. 4 and 5 , the switch assembly  28  has an electrical cable  50  extending through the housing  30  and connected at one end to the microswitch  32 . A seal is provided between the electrical cable  50  and the housing  30  to maintain the sealed environment in the housing around the microswitch  32 . In one embodiment, the electrical cable  50  has a pair of mating connectors  60  and  62  ( FIG. 7 ) releasably connected to each other adjacent to the switch assembly  28 . In one embodiment, a short length of heat-shrink tubing is provided over both connectors  60  and  62 .  
         [0039]      FIG. 7  is a schematic view showing the electrical cable  50  routed along selected portions of the vehicle  10  and connected to the vehicle&#39;s electrical center  54 . In one embodiment, the electrical cable  50  extends from the switch assembly  28  and is routed along the existing vehicle&#39;s wire bundles, such as along the driver&#39;s side. The electrical cable  50  is secured to the vehicle&#39;s wire bundles using conventional wire ties or other conventional securing mechanisms.  
         [0040]     The end of the electrical cable  50  opposite the switch assembly  28  is attached to a relay assembly  52  that connects to the electrical center  54 . The relay assembly  52  is coupled to a warning indicator  55 . Accordingly, when an improper load condition exists and the trigger member  34  causes the microswitch  32  to move to the activated position, the signal generated from the microswitch is provided to the relay assembly  52 . The relay assembly  52  provides a signal to the electrical center  54  so as to activate the warning indicator  55  so as to provide an audible and/or visual warning to the user that the improper load condition has occurred.  
         [0041]     In one embodiment, the relay assembly  52  is connected to the electrical center  54  so as to activate an audible warning indicator  55 , such as the vehicle horn or an auxiliary horn, that generates a sound indicating that an improper load condition exists. The audible warning indicator  55  will continue to sound until the load is lessened or shifted so as to move the microswitch  32  back to the normal, inactive position. In an alternate embodiment, a visual warning indicator, such as flashing vehicle lights or an auxiliary warning light, will appear to indicate that an improper load condition exists. In yet another alternate embodiment, both audible and visual warning indicators can be used.  
         [0042]     As best seen in  FIG. 8 , the relay assembly  52  includes two relays  64  and  66  mounted on a mounting plate  68 . The first relay  64  connects to the vehicle&#39;s start relay in the electrical center  54  ( FIG. 7 ), and the second relay  66  connects to the vehicle&#39;s horn relay, also in the electrical center. The relay assembly  52  is configured so that, when the switch assembly  28  ( FIG. 7 ) is activated, the vehicle&#39;s horn will sound until the improper load condition has been corrected. The first relay  64  is configured so the load warning system  12  ( FIG. 7 ) will only provide the audible warning signal, e.g., sounding the vehicle&#39;s horn, when the vehicle is in park or neutral. If the vehicle  10  is in reverse or any drive gear, the load warning system  12  will not sound the horn if an improper load condition exists. When the vehicle  10  is being driven and it hits a large bump, the load warning system  12  of the illustrated embodiment will not sound the horn.  
         [0043]     As indicated above, the load warning system  12  draws no power when in the normal, inactive position, such that there is no drain on the vehicle&#39;s battery, and no current flows through the starter relay unless the ignition key activates the starter. Accordingly, the load warning system  12  of the illustrated embodiment has no separate ON/OFF switch, no lights to manually turn on or off, and nothing for the operator to do except to reduce or shift the load  14  on the vehicle  10  when the load warning system  12  indicates an improper load condition has occurred.  
         [0044]     In an alternate embodiment of the invention, the relay assembly  52  can be coupled to a different audible warning device, such as an alarm, or to a visible warning indicator mechanism, such as a warning light or the like. In another embodiment, the load warning system can bypass the starter relay, and the system includes a data processor  80  (shown in phantom lines in  FIG. 7 ) operatively coupled to the switch assembly  28 . The processor  80  is configured to provide continual monitoring of the switch assembly  28  to determine the frequency and/or duration of time that the microswitch  32  is in the activated position while the vehicle is stationary or being driven. When a selected condition exists, such as a number of activations over a selected period or specified duration of time that the microswitch  32  remains in the activated position, the processor  80  will provide a signal to activate the warning indicator  55 . In this embodiment, if the vehicle  10  is in motion and the trigger member  34  is occasionally activated because of road disturbances, the processor  80  will be able to identify these occasional activations without activating the warning indicator  55 . If, as an example, the load  14  in the vehicle  10  shifts during transportation, thereby resulting in substantially continuous activation of the microswitch  32  to indicate an improper load condition, the processor  80  would detect the change and a warning signal would be provided to the user that an improper load condition exists.  
         [0045]     When the load warning system  12  is installed on the vehicle  10  either as original equipment or as a retrofit, the system is calibrated to provide a warning signal when the load exceeds a selected maximum load. The load warning system  12  can be easily and quickly calibrated by placing a known maximum load  14  into the bed  16  of the vehicle  10  at a selected location and then adjusting the position of the switch assembly  28  relative to the bracket  40 . In one embodiment shown in  FIG. 2 , the calibration load  14  is 3,000 pounds±30 pounds. The load  14  has a footprint of approximately 30″×30″, and the load is placed so the load&#39;s center is approximately 26″±3″ behind the front of the bed  16 . The load  14  is centered laterally within approximately 2″ of the vehicle&#39;s centerline.  
         [0046]     As best seen in  FIG. 3  from under the vehicle  10 , the fasteners connecting the switch assembly  28  to the frame bracket  22  are then loosened. The switch assembly  28  is then rotated until the trigger member  34  contacts the engagement portion  44  of the bracket  40  just enough so that the microswitch  32  moves to the activated position thereby sounding the horn. The switch assembly  28  is then secured in this position relative to the frame bracket  22 , so as to be in a final calibrated position. After the switch assembly  28  is secured in the final calibration position, a person should be able to push upwardly on a portion of the frame  17  rearward of the rear axle  18  enough to cause the trigger member  34  to move the microswitch  32  back to the normal, inactive position.  
         [0047]     The configuration of the load warning system  12  on the vehicle  10  as discussed above is such that the location of the measurement point determines how the system will react as the center of gravity of the load  14  is moved around on the bed  16  or other load support area of the vehicle. The load warning system  12  is configured to minimize the effect of a driver&#39;s weight. The load warning system  12  of the illustrated embodiment is also configured to generate the warning signal in the event a reduced load, such as approximately 70% of the maximum load, is placed too far rearward in the bed  16  of the vehicle  10 . In this configuration, the reduced load will cause the compression of the suspension system  20  and rotation of the frame  17  relative to the rear axle  18 , thereby indicating an improper load configuration. In this overload configuration, the load rearward of the rear axle  18  can cause the forward portion of the vehicle&#39;s frame  17  to lift so as to reduce the weight on the vehicle&#39;s front wheels, thereby resulting in the overload condition at the rear end and an undesirable underload condition at the forward end of the vehicle.  
         [0048]     After the load warning system  12  is calibrated, the calibration load is removed from the bed  16  and the vehicle  10  can be used in regular operation. The load warning system  12  can be easily recalibrated as needed, for example, if the vehicle&#39;s suspension system  20  relaxes or softens over time. The load warning system  12  can also be easily and quickly tested by reaching under the vehicle  10  and manually moving the trigger member  34  to confirm that the warning signal will be generated in an improper load condition. If any system components have been damaged, or require replacement or maintenance, such as the microswitch  32 , the flexible trigger member  34 , the brackets  22  and  40 , the electrical cable  50  or the like, the component can be quickly and easily removed and replaced, thereby minimizing the amount of time the vehicle is out of service.  
         [0049]     In one embodiment, the load warning system  12  includes a data collector  70 , shown schematically in  FIG. 7 , operatively connected to the vehicle  10  and to the switch assembly  28 . The data collector  70  is configured to collect data during operation of the vehicle, and the data can be downloaded or otherwise output for analysis. The data collector  70  can be configured to collect and output data, including, for example, the time, date and duration of operation, or the frequency or duration of activation of the switch assembly. The data collector  70  can also be connected to a conventional load cell (not shown) to collect and output data about the weight of the load(s) applied to the vehicle  10 .  
         [0050]     The data from the data collector  70  can then be used in any number of ways, including determining when routine maintenance may be needed for the load warning system  12 . If the vehicle is a rental vehicle, the data collector  70  could be used to determine whether conditions existed during operation that justifies different charges or costs to the renter of the vehicle. Accordingly, the load warning system  12  can be used for more than just determining if an improper load condition exists.  
         [0051]     From the above detailed description, it will be appreciated that specific embodiments of the invention are described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention.