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CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. Provisional Application Ser. No. 60/134,710, filed May 18, 1999, which application is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     The present invention relates to a ladder support device that attaches to a moving vehicle, such as a panel van or pickup truck. The device, which facilitates the transport and deployment of a ladder, can be used with a relatively long extension ladder, and provides a stable support for the ladder when it is deployed and extended. 
     Extension ladders are commonly used to allow workers to ascend to roofs, or other high points on buildings or billboards. These extension ladders can reach to heights of about 40 feet. Relatively short ladders can generally be handled by a single individual, but with heights of 30 to 40 feet two or more persons may be required to hoist the ladder from its transportation vehicle and into position against the building. Moreover, extremely long ladders tend to be more susceptible to motion in the wind, and require the user to be extremely cautious that the center of gravity of the ladder and user is not shifted so as to cause the ladder to “kick out” or slip from its properly mounted position. 
     Previous attempts have been made to find relatively easy means of hoisting and mounting extension ladders, such as described in U.S. Pat. No. 2,586,531, issued to Gordon; U.S. Pat. No. 3,043,398, issued to Bakula; and U.S. Pat. No. 4,408,680, issued to Ross. Each of the above patents describe devices that allow a ladder to be transported in the horizontal position, typically resting on the top of the transporting vehicle, and then allow the ladder to be deployed into a vertical position at the work site. The device of the &#39;531 patent includes a modified vehicle bumper with pockets which accept the feet of the ladder, and angled rails which hold the ladder in the desired upright position. The devices of the &#39;398 and &#39;680 patents secure the base of the essentially vertical ladder to the bumper, then rely on angled rails or cables to hold the extended ladder in position. In each of these cases, even with the ladder properly positioned, there is little support for the deployed ladder, so the user must be cautious when using the ladder in a strong breeze. Moreover, because the ladder is secured to the bumper of the transport vehicle, the vehicle must be properly positioned relative to the intended use site or the user will not be able to reach the building with the ladder in the vertical position. 
     U.S. Pat. No. 4,858,725, issued to Griffin, and shown in FIGS. 1 and 2, describes a ladder brace that attaches to a moving vehicle, such as a panel van. The device includes a hinge ( 12 ) which attaches to the lower portion of a vehicle and allows the device to rotate approximately 90° (from a position parallel to the ground (open) to a position that is perpendicular to the ground (closed)). Extending from the hinge ( 12 ) is a first pair of braces ( 14 ,  16 ) which intersect a second pair of braces ( 20 ,  22 ), forming two T-shaped structures. Support braces ( 24 ,  26 ) further connect the first braces ( 14 ,  16 ) to the second braces ( 20 ,  22 ); and two cross-members ( 28 ,  30 ) are positioned between the T-shaped structures. In use, a pivot pin ( 40 ) is threaded through the rung of a metal ladder to secure the ladder to the second braces of the device. When the ladder is deployed, a safety stop ( 32 ) can be positioned to abut against the lower portion of the ladder to revent the ladder from moving. 
     The device of the &#39;725 patent allows the ladder to be deployed in several positions —straight up, toward the rear of the vehicle, and away from the rear of the vehicle—and allows the ladder to be moved from the horizontal position to the vertical position by a single individual. However, the device of the &#39;725 patent requires that the vehicle be positioned directly in front of the work site so the ladder can be deployed at the proper angle to the site; does not provide for unexpected movement of the ladder, such as having a wind from the opposite direction causing the ladder to sway backward; does not provide an easy way for the user to alight to or descend from the ladder once it is in position, rather the user must step between the braces to reach the ladder; uses only the safety stop, which is near the base of the ladder, to secure the ladder in position; and is not designed to accommodate ladders of varying widths, which are common in the industry. 
     Thus, it is an object of this invention to provide a ladder support device which can be secured to a vehicle, and used to transport a ladder on the vehicle in an essentially horizontal position; which can be deployed to an essentially vertical position by the user without assistance; which provides features which may be used to reduce the risk of the ladder tilting by more than a limited angular range, even in adverse weather conditions; which allows the user to easily alight to and descend from the ladder; and which can be deployed in varying angular relationships relative to the vehicle so that it is not necessary for the vehicle to be directly aligned with the intended work site. 
     SUMMARY OF THE PREFERRED EMBODIMENT 
     The present invention relates to a ladder support device that attaches to a moving vehicle, such as a panel van or pickup truck. The device includes a ladder mounting section, adaptable for variable width and length extension ladders, and having safety brackets and skid pads; and a platform leading from a rotatable latch to the ladder mounting section. The safety brackets provide that a deployed and extended ladder will have a very limited range of motion, thereby minimizing the risks of the ladder kicking out or tilting. The skid pads allow the vehicle to be repositioned slightly, with the ladder deployed, for better access to the work site. The platform allows the user to gain secure footing before alighting to and upon descending from the ladder, and the rotatable mount at the end of the catwalk allows the ladder support device to be moved through a wide arc relative to the vehicle, thus allowing the ladder support to be moved into the proper work position even if the vehicle is at an angle other than directly in front of the work site. When attached to a towing hitch of a vehicle, the ladder support device is adapted such that the ladder mounted to the support can be transported on the vehicle in an essentially horizontal position and can be deployed to an essentially vertical position by the user without assistance. 
    
    
     DESCRIPTION OF FIGURES 
     FIG. 1 is a perspective view of a prior art ladder brace in the transport position; 
     FIG. 2 is a perspective view of the prior art brace of FIG. 1 in the deployed position; 
     FIG. 3 is a side view of a ladder support device made in accordance with the present invention in the transport position with a vehicle and ladder shown in phantom; 
     FIG. 4 is a side view of the ladder support device of FIG. 3 showing the support device as it is being deployed with a vehicle and ladder shown in phantom; 
     FIG. 5 is a side view of the ladder support device of FIG. 3 in the deployed position with a vehicle and ladder shown in phantom; 
     FIG. 6 is a side view of the ladder support device of FIG. 3 with the ladder positioned to reach a work site; 
     FIG. 7 is a top view of the ladder support device of FIG. 3 in the deployed position and at an angle relative to the vehicle; 
     FIG. 8 is an exploded perspective view of the ladder support device of FIG. 3; 
     FIG. 9 is an exploded perspective view of an alternative embodiment of a ladder support device made in accordance with the present invention; and 
     FIG. 10 is a cross-section of the platform piece of FIG. 9 taken along line  10 — 10 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The ladder support device depicted in the various Figures is selected solely for the purposes of illustrating the invention. Other and different ladder support devices may utilize the inventive features described herein as well. 
     Reference is first made to FIGS. 3 through 8 in which the ladder support device constructed in accordance with the present invention is generally noted by the character numeral  110 . The ladder support device  110  is designed to allow the user to reversibly attach the ladder support  110  to a tow hitch  196  on a vehicle  194 , and to transport a standard extension ladder  190 , having side rails  191  and rungs  192  (not shown), in an essentially horizontal position on the vehicle  194 , as shown in FIG.  3 . Once at the work site, the user can then deploy the ladder  190  by lowering the ladder support  110 , as shown in FIG. 4, until the ladder  190  is in an essentially vertical position and the feet  124 ,  124 ′ of the ladder support  110  rest on the ground  198 , as shown in FIG.  5 . With the feet  124 ,  124 ′ situated, the ladder  190  can be tilted, as shown in FIG. 6, to allow the user to reach the work area. As shown in FIG. 7, in a preferred embodiment, the ladder support  110  can be rotated relative to the vehicle  194  through a wide arc θ—from a position angled toward the passenger side of the vehicle to a position angled toward the driver side of the vehicle—thus allowing the ladder support  110  to be moved into the proper work position even if the vehicle  194  is at an angle other than directly in front of the work site. 
     FIG. 8 shows the ladder support device  110  in greater detail. The ladder support  110  has as major components two essentially identical frames  112 ,  114 , a platform  116 , a rung mount  136 , and a pair of rotatable brackets  132 ,  132 ′. The first frame  112  includes an essentially horizontal brace  120 , and an essentially vertical brace  122  that forms a “T” with the horizontal brace  120 , with one end of the vertical brace  122  forming a foot  124 , and the opposite end forming a head  126 . That is, each horizontal brace  120 ,  120 ′ is secured essentially perpendicular to its respective vertical brace  122 ,  122 ′ at a position intermediate the head  126 ,  126 ′ and foot  124 ,  124 ′ of the respective vertical brace  122 ,  122 ′. A leg support brace  130  connects the foot  124  to the horizontal brace  120 . Because the leg brace  130  adds structural support to the frame, the leg brace  130  preferably forms an angle (φ of less than about 60° with the vertical brace  122 . The second frame  114  is essentially identical to the first frame  112 , and includes an essentially horizontal brace  120 ′, an essentially vertical brace  122 ′, and a leg brace  130 ′. Optionally, skid pads  140 ,  140 ′ may be included on the feet  124 ,  124 ′ to allow the user to move the vehicle  194 , and hence the ladder support  110 , by several inches with the ladder support  110  in the deployed position without causing damage to the feet  124 ,  124 ′ and braces  122 ,  122 ′,  130 ,  130 ′. 
     A platform  116  is fixedly attached to the horizontal braces  120 ,  120 ′ of the first and second frames  112 ,  114 , and holds the frames  112 ,  114  in mirror image juxtaposition relative to each other. The platform  116  is preferably made from a material of sufficient rigidity that the ladder support user can stand on the platform  116  without causing the platform  116  to deform or collapse. Optionally, the platform  116  can be made from an open mesh material to allow the user to scrape mud or other debris from his work shoes before ascending the ladder  190 . The platform  116  can be attached to the frames  112 ,  114  by welding, bolts, metal anchors, or by similar methods. In a preferred embodiment, the rear of the platform  116  includes a crossbar  117  mounted between the horizontal braces  120 ,  120 ′. The crossbar  117  provides additional structural support for the ladder support  110 , and also creates a “kick-stop” to prevent a deployed ladder  190  from kicking out from under the user. Optionally, other crossbars  119  may be added between the braces  120 ,  120 ′ under the platform  116  for additional structural support. 
     At the forward end of the platform  116  is a hitching section  150  that includes a bracket  154 , secured to the horizontal braces  120 ,  120 ′ such that the braces  120 ,  120 ′ can be tilted by about 90° relative to the bracket  154 , as shown in FIGS. 3 and 5; and a ring  156 , positioned between the front edge  152  of the platform  116  and the bracket  154 , and fixedly attached to the bracket  154 . The ring  156  is used to secure the ladder support device  110  to the vehicle  194 , and preferably has sufficient freedom of movement that the ring, and hence the ladder support  110 , can be rotated relative to the vehicle  194  through a wide arc θ, such as shown in FIG. 7, thus allowing the ladder support  110  to be moved into the proper work position even if the vehicle  194  is at an angle relative to the work site. In a preferred embodiment, a cylindrical post  158 , which fits snuggly within the ring  156 , is secured to a flange  160  that connects to a tow hitch  196  mounted on the vehicle  194 , and the ring  156  is held onto the post  158  with a key or similar locking device. At the work site, the key can be released to allow the ring  156  to move relative to the post  158 . If necessary to create a snug fit between the ring  156  and the post  158 , washers or additional rings can be added to the post  158 . Different types of hitch connections may be used to secure the ladder support  110  to the vehicle  194 , but preferably, the connection selected should allow the ring  156  freedom of movement through the angle θ. 
     Referring again to FIG. 8, on each frame  112 ,  114 , between the head  126 ,  126 ′ and the horizontal brace  120 ,  120 ′ are apertures  128 ,  128 ′. Threaded bolts  134 ,  134 ′ project through the apertures  128 ,  128 ′, respectively, to secure a hollow cylindrical rung mount  136  between the frames  112 ,  114 . The mount  136 , which is preferably threaded internally on either end, should have an exterior diameter small enough to fit within a rung  192  of the standard extension ladder  190 . When used with a ladder  190 , the rung mount  136  is slipped within a rung  192  of the ladder  190 , the ladder  190  is positioned between the frames  112 ,  114 , and the bolts  134 ,  134 ′ are passed through the apertures  128 ,  128 ′ and tightened within the respective ends of the rung mount  136 , thereby holding the ladder  190  onto the ladder support  110 . Because ladders can vary in width, typically from about 17 inches to about 21 inches, the ladder support  110  is designed to accommodate the wider ladders without any modification. However, to provide narrower ladders with a relatively tight fit between the ladder  190  and the frames  112 ,  114 , optionally one or more spacers  138 , each having an aperture  139  large enough to fit over the rung mount  136 , may be added to the rung mount  136 . When spacers  136  are used, the ladder  190  positioning procedure is essentially the same as noted above, except that the spacers  138  are added to the rung mount  136  before the ladder  190  is slipped between the frames  112 ,  114 , and the bolts are then attached to the rung mount  136 . 
     Near the head  126 ,  126 ′ of each frame  112 ,  114  is attached a movable bracket  132 ,  132 ′, respectively. Each bracket  132 ,  132 ′ has a “C” -shape, with the width of the “C” preferably being large enough to accommodate the side rail  191  of the ladder  190 , such as shown in FIG. 5, and can be moved relative to its respective frame  112 ,  114  such that the bracket  132 ,  132 ′ can rest inwardly, i.e. between the frames  112 ,  114  and essentially over the rung mount  136 , or outwardly, i.e. away from the rung mount  136 . The brackets  132 ,  132 ′ may be attached to their respective frames  112 ,  114  using any known fastening devices that will allow the brackets  132 ,  132 ′ to flip over the frames  112 ,  114 , such as metal brads, screws, or similar fastening devices. The brackets  132 ,  132 ′ serve two functions on the ladder support device  110 . When the ladder  190  is secured for transport, the brackets  132 ,  132 ′ are rested away from the rails  191  of the ladder  190  so the ladder  190  can tilt slightly as the ladder support device  110  is moved from the transport to the deployed position, or vice versa, such as shown in FIG.  4 . This tilting of the ladder  190  has been found to make deployment and stowing of the ladder  190  easier for the user. When the ladder  190  is tilted into position at the work site, as shown in FIG. 6, the brackets  132 ,  132 ′ are turned inwardly (toward the ladder) to prevent the ladder  190  from tilting backward by more than a limited amount even in a very strong wind, i.e. the brackets  132 ,  132 ′ stop the backward movement of the ladder  190  by creating a blockade that limits the ladder&#39;s  190  motion. 
     To make the ladder support device  110  easier to move from the transport position to the deployed position, one or more handles may optionally be attached to the frames  112 ,  114 . In a preferred embodiment, a first handle  170  projects from the vertical braces  122 ,  122 ′ away from the platform  116 , but in essentially the same plane as the platform  116 , and a pair of handles  172 ,  172 ′ projects from near the heads  126 ,  126 ′ of the vertical braces  122 ,  122 ′, away from the platform  116 . The handles  170 ,  172 ,  172 ′ provide grips for the user to hold as the ladder support  110  is lowered from or returned to the transport position. Although the handles are not required for the ladder support device  110  to function as intended, the handles facilitate the deployment of the ladder support  110  allowing even relatively small users to deploy the support  110  without assistance. 
     FIGS. 9 and 10 show an alternative embodiment  210  of the ladder support device  110  of FIGS. 3-8. The device  210  is essentially identical to the ladder support device  110  except that the platform  216  and horizontal braces  220 ,  220 ′ are divided into two units,  211 A,  211 B, having platforms  216 A,  216 B, and horizontal braces  220 A,  220 B,  220 ′A,  220 ′B. One pair of braces  220 A,  220 ′A has slightly smaller exterior dimensions than the second pair of braces  220 B,  220 ′B, so that the smaller braces  220 A,  220 ′A can slide into the larger braces  220 B,  220 ′B as though fitting within sleeves, and creating an overlap region  221 . In the overlap region  221 , the platform  216 A attached to the smaller braces  220 A,  220 ′A slides under the larger brace platform  216 B. The units  211 A,  211 B can be held together at the overlap region  221  by screws, bolts, or similar fasteners that allow the user to adjust the degree of overlap  221 . Having the platform  216  divided allows the user to put the ladder support device  210  in the transport position on the user&#39;s vehicle, then to adjust the length of the platform  216  to best fit that particular vehicle so that the ladder  190  and ladder support  210  can lie essentially horizontal on the vehicle during transport, regardless of the vehicle&#39;s height. 
     It is understood that, in light of a reading of the foregoing description and drawings, those with ordinary skill in the art will be able to make changes and modifications to the present invention without departing from the spirit or scope of the invention, as defined herein.

Summary:
A ladder support device attaches to a towing hitch of a vehicle, such that the ladder can be transported in an essentially horizontal position and deployed in an essentially vertical position. The ladder support device includes safety brackets that limit the range of motion of the extended ladder, a platform that provides a user with secure footing before alighting to and upon descending from the ladder, and a rotatable mount that allows the ladder support device to be moved into the proper work position.