Abstract:
A trailer support wheel assembly having a wishbone frame pivotally connected to the trailer frame at two rear mounting points and adjustably connected to the trailer frame at a single forward point. A resilient suspension assembly and spindle is contained by the wishbone frame assembly, and the spindle is further connected to one or more wheels which may be lowered into contact with the ground. The wishbone frame assembly may be adjustably positioned to permit the wheels to carry a greater or lesser load portion of the trailer as it is connected to a vehicle.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an improvement in the load-carrying capacity of a vehicle connected to a trailer. Specifically, the invention relates to a wheeled assembly which is connected near the front of a trailer to relieve some of the loading effects on the trailer hitch which is connected to the towing vehicle. 
     There is a related application, Ser. No. 08/496,134, filed Jun. 28, 1995, which discloses an alternative embodiment for a trailer-loading support. 
     Trailers intended for towing behind relatively light-weight vehicles are becoming increasingly heavy as the loads become ever larger. Such trailers may be used for transporting boats, construction equipment, other vehicles, motor homes, and animals. All such trailers are typically connected to the towing vehicle by a ball trailer hitch, wherein the forward tongue of the trailer is formed into a ball receiver and the ball is connected to the vehicle either directly or by a substrate assembly. Optimally, the trailer loading effect on the vehicle is balanced so that the load on the motor vehicle is no greater than approximately 350-500 pounds; the balance of the trailer weight being carried by the trailer wheels. The downward force on the towing vehicle via the trailer ball is called the tongue weight, and this tongue weight creates an additional load on the suspension of the motor vehicle which can become dangerous at excessive loading levels. Motor vehicles typically have a maximum limit prescribed for the vehicle and increasing the loading effect beyond the prescribed maximum may result in unsafe performance of the motor vehicle, both from the standpoint of stressing the motor vehicle&#39;s suspension and also by way of reducing the traction of the front wheels of the vehicle. 
     The present invention provides an apparatus for relieving the loading conditions on a motor vehicle by providing an adjustable wheeled assembly to carry a sufficient portion of the trailer tongue weight so as to provide a balanced load condition for the towing vehicle and for the towed trailer. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a wheeled assembly which is pivotally connected to a trailer frame at one of its ends and is adjustably connected to the trailer frame at another of its ends. A resiliently mounted spindle is mounted proximate the center of the wheel assembly and supports one or more wheels which bear on the road surface to partially carry the front load of the trailer. The adjustable connection of the wheel assembly permits adjustment of the relative load-carrying capacity of the wheeled assembly. The spindle which supports the wheels is rotatable to permit the wheels to turn in the direction of movement of the trailer and one or more steering dampeners are provided to control the rate of turning of the spindle. 
     It is the principle object of the present invention to provide a wheel assembly for carrying a portion of the tongue weight of a trailer. 
     It is another object and advantage of the invention to provide a wheel assembly for carrying tongue weight of trailer and being steerable to move in the direction of motion of the trailer. 
     It is a further object and advantage of the invention to provide a trailer support wheel assembly which is adjustable for carrying multiple trailer tongue weight portions. 
     It is another object of the invention to provide a wheeled assembly which may be readily connected and adjusted by utilizing the conventional trailer jack which is typically found on a trailer tongue assembly. 
     Other and further objects and advantages of the invention will become apparent from the following specification and claims and with reference to the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an elevation veiw, in partial breakaway, of the trailer support wheel assembly connected to a trailer; 
     FIG. 2 shows a partial top view of the invention connected to a trailer frame; 
     FIG. 3 shows a drawing of the invention in exploded view; 
     FIG. 4 shows a partial top view of the invention, illustrating the turning ability of the wheel assembly; and 
     FIG. 5 shows an elevation view of an alternative suspension assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows the invention in elevation view connected to a trailer frame  10  which is shown in partial cut-away view. Trailer frame  10  has a forwardly-extending tongue  12  with a ball receiver  22  at its forwardmost end. A trailer jack  14  is affixed proximate the front of tongue  12 . The jack  14  has a motor drive or crank mechanism  16  which movably positions a jack shaft  18  upwardly or downwardly. Jack shaft  18  has a foot pad  20  which can be extended to contact the ground surface. Trailer frame  10  has a cross-frame member  11  and a cross-frame member  13  for strengthening the frame assembly. 
     Referring to FIGS. 1-4, a wheel assembly  24  is pivotally and adjustably connected to trailer frame  10 . A pair of U-brackets  26 ,  28  are affixed to cross-frame member  11  by bolts or weldments. Each U-bracket  26 ,  28  has a pair of aligned holes through the respective brackets, the holes being sized to accept hinge pins  32 ,  34 . A wishbone frame  30  has a pair of downwardly depending frame sections  36 ,  38  having aligned holes through their respective ends; hinge pins  32 ,  34  respectively pivotally connect frame sections  36 ,  38  to brackets  26 ,  28 . These connections permit wheel assembly  24  to pivot about the axis of alignment of hinge pins  32  and  34 . 
     The front end of wishbone frame  30  is formed into a downwardly directed frame section  40  having a plurality of aligned holes  42  at spaced apart intervals along its length. The lower end of frame section  40  has a forwardly projecting tab  44  which will be hereinafter described. A vertical cylinder  50  is affixed to wishbone frame  30  proximate its center and cylinder  50  has a pair of aligned slots  52  passing therethrough. A linch pin  54  is sized to insert through the slots  52 . 
     A front bracket  46  is affixed to cross frame member  13  by bolts or weldment. Front bracket  46  has a pair of elongate slots  48  through its respective side walls in aligned relationship. A bolt  45  is sized to fit through elongate slots  48  and also to fit through holes  42  in frame section  40 . 
     A compression spring  60  is fitted over the exterior of cylinder  50  and a spindle  62  is fitted into the interior of cylinder  50 . Spindle  62  has a pair of elongate slots  63  proximate its upper end and elongate slots  63  are sized to accept linch pin  54 . Spindle  62  has a curved lower end  64  with an axle connection  65  proximate its lower extremity. Axle connection  65  is adapted to receive an axle which passes through the wheel hubs for wheels  66 . A turning arm  56  is affixed to spindle  62 , and turning arm  56  is rotatable with spindle  62  about the vertical axis of spindle  62 . 
     A pair of L-brackets  33 ,  35  are each respectively connected to an inner end of hinge pin  32 ,  34 . A pair of steering dampers  72 ,  74  each have respective ends  73 ,  75  connected to L-brackets  33 ,  35  by means of threaded fasteners  76 ,  78 . The respective other ends  83 ,  85  of steering dampers  72 ,  74  are connected to turning arm  56  by similar threaded fasteners,  86 ,  88 . Steering dampers  72 ,  74  are conventional dashpot-type cylinders typically having air as the damping medium. Each of the steering dampener ends  73 ,  75 ,  83 ,  85  have a rubber grommet for receiving the respective threaded fasteners. These rubber grommets permit a certain degree of lateral movement of the steering dampers relative to the brackets to which they are connected. A small amount of lateral movement is to be expected, as the wheel assembly  24  will move upwardly and downwardly as it encounters different types of road surfaces. Of course, an alternative and equivalent embodiment of this invention could utilize a single steering dampener connected as described instead of the two steering dampeners which are described with reference to the preferred embodiment. 
     FIG. 4 shows a top view of the apparatus in partial breakaway to illustrate the turning mechanism associated with the wheels  66 . In this example, the wheels as shown turn sharply to the left with turning arm  56  correspondingly turned to the left. Steering damper  74  is compressed as a result of its connection to turning arm  56  and steering damper  72  is extended as a result of this connection to turning arm  56 . Since both steering damper  72  and steering damper  74  comprise cylinders and pistons having air in the cylinders, both steering dampers will resist sudden extension or retraction and will thereby dampen or slow the turning motion of wheels  66 . This prevents any rapid oscillation or turning motions from taking place with respect to wheels  66  and controls the rate of turning under operating conditions. 
     In operation, the trailer jack  14  is extended to permit foot pad  20  to contact the ground; and the trailer jack is further extended to raise the ball receiver sufficiently to permit a vehicle trailer ball to be positioned beneath the ball receiver  22 . Trailer jack  14  is then retracted until it disengages from contact with the ground, and the degree of loading of the trailer on the trailer hitch mechanism is assessed. Ideally, the trailer tongue should be positioned so as to have approximately a 17-inch clearance from the ground; and the trailer frame and vehicle frame should be relatively horizontal with respect to the ground. If the trailer hitch is overloaded, the trailer frame and vehicle frame will be relatively lowered and the trailer ball receiver will be less than 17 inches above the ground. In this case, the jack  14  is again activated to raise the trailer tongue and bolt  45  is inserted through one of the plurality of openings  42  through front section  40 . To share a greater portion of the trailer load, front section  40  is raised to permit bolt  45  to pass through one of the lower holes in front section  40 . After bolt  45  has been secured in the proper position, the trailer jack is again retracted to lower the entire assembly into contact with the ground so that the relative horizontal positions of the trailer frame and vehicle can be reassessed. This process is continued until the trailer frame is relatively horizontal to the ground and the trailer ball receiver  22  is approximately 17 inches above the surface of the ground. 
     For stowing the wheel assembly during periods of inoperation, the linch pin  54  may be inserted through slot  52  of cylinder  50  and slot  63  of spindle  62 . This will lock the spindle and wheels into a fixed raised position relative to the wishbone frame  30 . The forwardly projecting tab  44  on the front section  40  of wishbone frame  30  provides a safety mechanism in the event bolt  45  becomes disconnected or broken. In this situation, the front section  40  of wishbone frame  30  will tend to move upwardly in unconstrained fashion will tab  44  contacts the underside of cross frame member  13 . This engagement will permit no further dropping of the trailer frame front end and will protect against a catastrophic failure. 
     The respective ends  73 ,  83  of damper  72  and  75 ,  85  of damper  74  will typically include a rubber grommet for facilitating the connection with the fasteners. The respective rubber grommets permit some lateral and longitudinal motion of the respective ends of the steering damper  72 ,  74  in a manner which is typically associated with the connection of shock absorbers and the like. 
     FIG. 5 shows an alternative embodiment of the invention in elevation view and connected to a trailer frame  10 , which is shown in partial cutaway view. A wheel assembly  24   a  is pivotally attached to a cross-frame member  11  at two points, as described earlier. A pair of U-brackets  26 ,  28  are affixed to cross-frame member  11  as described, and each U-bracket has a pair of aligned holes through the respective brackets which are sized to accept hinge pins  32 ,  34 . The front portion of wheel assembly  24   a  has a downwardly-directed frame section  40  having a plurality of aligned holes  42 , wherein each of the holes  42  may be selectively aligned with a slot in front bracket  46 . A vertical cylinder  50   a  is affixed to the wishbone frame  30 , and a piston  51  is slidably movable within the inside of cylinder  50   a.  Piston  51  has at least a closed top surface, and cylinder  50   a  has an open bottom end for permitting piston  51  to be accepted into cylinder  50   a.  An air bag  55  is placed in the space between the top surface of piston  51  and the undersurface of the top wall of cylinder  50   a.  An air valve  57  is attached to air bag  55  and projects through the top wall of cylinder  50   a  via sealable grommet  53 . The air pressure into air bag  55  may, therefore, be selectively controlled by adding or removing air from the air bag via air valve  57 . In operation, the compressible air bag serves as a resilient suspension means for controlling the loading effects on the wheel assembly  24   a.  The air bag is also able to absorb the shock of relative movement between  50  and  51  and cylinder  50   a,  as might be caused by operating the vehicle over a road surface. In all other respects, the apparatus disclosed in FIG. 5 is similar to the apparatus previously disclosed herein. Of course, other alternative embodiments may be devised to provide a similar operation to that described herein. For example, a torsion bar suspension assembly might be adapted to serve the functions described herein, or a combination of air and hydraulics might be used in connection with a piston/cylinder operation to achieve the same purpose. 
     The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof; and it is, therefore, desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.