Abstract:
A double-castered wheel trailer having a pair of lockable caster wheels. The lockable caster wheels are adapted to be locked for a trailing mode of operation and a backing mode of operation. The double-castered wheel trailer further includes a multi-planar adapting hitch-to-trailer coupler. The multi-planar adapting hitch-to-trailer includes a horizontal pivot member adapted to be secured to a pair of hitch balls and pivot in a horizontal plane about the towing vehicle. Further included is a vertical swivel member coupled to the horizontal pivot member and the trailer frame to independently rotate the trailer frame about said horizontal pivot member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to trailers adapted to be towed behind a vehicle and, more particularly, to an double-castered wheel trailer with direction locking caster wheels having a trailing locked position and a backing locked position. The double-castered wheel trailer further includes a multi-planar pivoting coupler. 
     2. General Background 
     My single beam trailer described in U.S. Pat. No. 5,368,325, entitled “UNIVERSAL SINGLE-WHEEL SINGLE BEAM TRAILER HAVING ADJUSTABLE BED” discloses a trailer which includes a single beam frame structure having a single caster wheel. I have determined that for heavier loads double caster wheels are needed. Moreover, I have determined that enhanced control is needed to maneuver the trailer in the trailing and backing modes. 
     Several other apparatus have been patented which are aimed at trailers for use with towing vehicles. 
     U.S. Pat. No. 4,664,403, issued to Livingston, entitled “HITCH ADAPTER FOR DOUBLE CASTER WHEEL TRAILER” discloses a trailer hitch with double caster-type wheels. The trailer hitch structure further includes hitch couplers and a forward swivel coupled to the hitch of the towing vehicle. 
     U.S. Pat. No. 4,512,593, issued to Ehrhardt, entitled “TRACKING TRAILER CONSTRUCTION” discloses a pair of laterally spaced-apart dependingly supported caster wheel assemblies interconnected for equal and simultaneous rotation. The main frame includes a pair of laterally spaced apart hitch structures for hitching the trailer to the towing vehicle. 
     U.S. Pat. No. 3,033,593, issued to Zaha, entitled “AUTOMOTIVE TRAILER” discloses a trailer having a pair of caster wheels which are adapted to be locked during trailing operation and unlocked during the backing operation. 
     U.S. Pat. No. 2,475,174, issued to Boone, entitled “TRAILER” discloses a trailer which is adapted to be coupled to a towing vehicle and which includes a pair of caster wheels. The Boone patent provides a locking means for locking the caster wheels about their vertical axis and releasing the rigid connection between the vehicle and the trailer so that the trailer may track behind the vehicle. 
     U.S. Pat. No. 5,463,885, issued to Warren, Sr., entitled “TRAILER WHEEL LOCK” discloses a pair of cover plates and a chain assembly. The cover plates cover the outer surfaces of the wheels. The chain assembly extends between the cover plates and is adapted to be locked via a padlock or the like. 
     U.S. Pat. No. 5,372,018, issued to Smith, entitled “WHEEL LOCK” discloses a wheel lock using a slidably moving C-shaped brackets adapted to be received over the tire and rim of a wheel. The C-spaced brackets are moved closer around the wheel and are adapted to be locked together via a padlock or the like. 
     Other patents in the art include U.S. Pat. No. 4,305,602, issued to Ungvari et al., entitled “UTILITY TRAILER”; U.S. Pat. No. 5,839,745, on application to Cattau et al., entitled “LOCK MECHANISM FOR FIFTH WHEEL HITCH”; U.S. Pat. No. 5,301,527, issued to Pollard, entitled “SECURITY DEVICE FOR A TRAILER”; none of which meets the needs of the present invention. 
     SUMMARY OF THE PRESENT INVENTION 
     The preferred embodiment of the double-castered wheel trailer with direction locking caster wheels of the present invention solves the aforementioned problems in a straight forward and simple manner. 
     Broadly, the present invention contemplate a double-castered wheel trailer for attachment to a pair of hitch balls secured to a towing vehicle comprising: a trailer frame; a pair of wheel assemblies coupled to the trailer frame; and an adaptable hitch-to-trailer coupler having a horizontal pivot member adapted to be secured to the pair of hitch balls and pivot in a horizontal plane about the towing vehicle and a vertical swivel member coupled to the horizontal pivot member and the trailer frame to independently rotate the trailer frame about said horizontal pivot member. 
     Preferably, each wheel assembly of the present invention comprises: a caster wheel; a bracket coupled to the caster wheel and pivotally coupled to the trailer frame, the bracket includes a horizontal plate, a vertically-extending arm, and tabs positioned approximately 180 degrees from each other and having holes formed therein; and, a locking pin adapted to be received in a respective of the two holes to lock the caster wheel in one of a trailing mode or a backing mode. 
     The horizontal pivot member of the present invention comprises: a transverse cross bar; a first arm perpendicularly coupled to the transverse cross bar and having a free end; and a second arm perpendicularly coupled to the transverse cross bar and laterally spaced from the first arm and having a free end. The horizontal pivot member further includes a first ball socket member integrated with the free end of the first arm; and, a second ball socket member integrated with the free end of the second arm. 
     The vertical pivot member of the present invention comprises a spindle rotatably coupled perpendicularly to the transverse cross bar and fixedly coupled to the trailer frame wherein the trailer frame is adapted to independently rotate with respect the transverse cross bar. 
     In view of the above objects, it is a feature of the present invention to provide a double-castered wheel trailer with direction locking caster wheels which is relatively simple structurally and thus simple to manufacture. 
     Another feature of the present invention is to provide a double-castered wheel trailer with direction locking caster wheels which is relatively simple to install or hitch to a towing vehicle. 
     The above and other objects and features of the present invention will become apparent from the drawings, the description given herein, and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     For a further understanding of the nature and objects of the present invention, reference should be had to the following description taken in conjunction with the accompanying drawings in which like parts are given like reference numerals and, wherein: 
     FIG. 1 illustrates a perspective view of the double-castered wheel trailer with direction locking caster wheels of the preferred embodiment of the present invention hitched to a vehicle (shown in phantom); 
     FIG. 2 illustrates a side view of the double-castered wheel trailer with direction locking caster wheels of the present invention; 
     FIG. 3 illustrates a top view of the double-castered wheel trailer with direction locking caster wheels of the present invention; 
     FIG. 4 illustrates a top view of the hitch assembly of the present invention; 
     FIG. 5 illustrates an end view of the hitch assembly of the present invention; 
     FIG. 6 illustrates an exploded view of the adaptable hitch-to-trailer coupler of the present invention; 
     FIG. 7 illustrates a perspective view of the adaptable hitch-to-trailer coupler of the present invention; 
     FIG. 8 illustrates an exploded view of the lockable caster wheel assembly; 
     FIG. 9 illustrates an top view of the lockable caster wheel assembly in the trailing position; and, 
     FIG. 10 illustrates an top view of the lockable caster wheel assembly with the wheel being pivoted toward the backing position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and in particular FIGS. 1-3, the double-castered wheel trailer of the present invention is generally referenced by the numeral  10 . The double-castered wheel trailer  10  of the present invention includes a trailer frame  20 , an adaptable hitch-to-trailer coupler  40  and two wheel assemblies  60   a  and  60   b  each of which includes a direction locking caster wheel  61   a,    61   b.    
     The trailer frame  20  includes a plurality of beams  22   a,    22   b,    22   c  and  22   d  welded together to from a square or rectangular frame structure having four corners. The trailer frame  20  further includes cross-beams  25   a  and  25   b  coupled perpendicular to the parallel beams  22   a  and  22   c.  In the preferred embodiment, the trailer frame  20  includes rear-trailer support bars  27   a  and  27   b.    
     Referring now to FIGS. 3-7, the trailer frame  20  is coupled to a vehicle  5  via an adaptable hitch-to-trailer coupler  40 . The adaptable hitch-to-trailer coupler  40  includes multiple degrees of maneuvering adaptability. As will be seen more clearly from the description below, the adaptable hitch-to-trailer coupler  40  provides for independent and secure horizontal and vertical pivoting. The horizontal-plane pivot member  41  include laterally spaced hitch couplers  43   a  and  43   b  which are capable of pivoting about an axis A 1  (FIG. 5) essentially perpendicular to the horizontal plane or ground. The vertical-plane pivot member  50  includes a swivel coupler or spindle  52  rotatably coupled to the horizontal-plane pivot member  41  and affixed to the trailer frame  20 . 
     During operation the horizontal-plane pivot member  41  allows the trailer  10  to pivot with respect to the rear of the vehicle  5  such as the result of turning a corner. Independent of the horizontal-plane pivot member  41 , the vertical-plane pivot member  50  is designed to pivot about the horizontal-plane pivot member  41  or axis A 2 , as best seen in FIG. 7 in the direction of ARROWS  1  and  1 ′. Thus, the vertical-plane pivot member  50  allows the caster wheels  61   a  and  61   b  to adapt to an uneven road or surface thereby the caster wheels  61   a  and  61   b  remain in rolling engagement with the uneven road or surface. 
     Referring now to FIG. 6, an exploded view of the adaptable hitch-to-trailer coupler  40  is shown wherein the manual locking devices or levers  45   a  and  45   b  and the corner frame supports  81   a  and  81   b  have been omitted from illustration. The horizontal-plane pivot member  41  includes transverse cross bar  44  and two parallel arms  41   a  and  41   b  coupled perpendicularly to the distal ends of the transverse cross bar  44 . The free-ends of the parallel arms  41   a  and  41   b  have integrated therewith hitch coupler  43   a  and  43   b,  respectively. The hitch couplers  43   a  and  43   b  include manual locking devices or levers  45   a  and  45   b,  respectively. 
     In the preferred embodiment, the parallel arms  41   a  and  41   b  are coupled to the transverse cross bar  44  via a mating connection. The parallel arms  41   a  and  41   b  are hollow and receive therein mated male extensions  44   a  and  44   b,  respectively. Corner frame supports  81   a  and  81   b  are provided, as best seen in FIGS. 3,  4  and  7 . The corner frame supports  81   a  and  81   b  are coupled to the transverse cross bar  44  and to the parallel arms  41   a  and  41   b.    
     In the exemplary embodiment, the vehicle  5  is equipped with two hitch balls  6   a  and  6   b,  as best seen in FIG. 5, mounted to the rear of the vehicle  5  in a known manner. The hitch couplers  43   a  and  43   b  are spaced apart hitch-ball sockets which are spaced the same distance as the hitch balls  6   a  and  6   b  of the vehicle  5  via the length of the transverse cross bar  44 . 
     The swivel coupler or spindle  52  of the vertical-plane pivot member  50  is supported by bracket  53  coupled by welding to the front beam  22   b  of the trailer frame  20 . A rear free end of the swivel coupler or spindle  52  is affixed to the cross beam  25   a.  The front free end  83  of the swivel coupler or spindle  52  is threaded and is rotatably coupled to the transverse cross bar  44  of the horizontal-plane pivot member  41 . Hence, the horizontal-plane pivot member  41  remains oriented in the preferred horizontal plane as the trailer automatically orients or adapts to the topography of the ground. In other words, the trailer&#39;s ability to automatically orient or adapt to the topography of the ground allows one side of the trailer to be elevated or offset in the vertical plane with respect to the other side so that the wheels  61   a  and  61   b  remain in contact with uneven ground. 
     The front free end of the swivel coupler or spindle  52  includes a threaded end having a reduced diameter. The reduced diameter is received in through hole  46  and secured therein via washers  47   a  and  47   b  and nut  48 . In the exemplary embodiment, the length of the swivel coupler or spindle  52  extends from the transverse cross bar  44  of the horizontal-plane pivot member  41  to the front cross bar  25   a  of the trailer frame  20 . 
     Since both of the wheel assemblies  60   a  and  60   b  are essentially identical, only one such wheel assembly will be described in detail. Referring now to FIG. 8, the details of the wheel assembly  60   a  are shown. The wheel assembly  60   a  includes a free caster wheel  61   a  adapted to rotate about axle  63 . The axle  63  is supported by arm  64  attached to the trailer frame  20  by a horizontal pivoting plate  69 . The top of the arm  64  is supported by a horizontal pivot or spindle  66 . 
     The wheel assembly  60   a  further include central kingpin  72  which is received in the Nylon washer  75 . The Nylon washer  75  serves to dampen the caster action and to prevent shimmy of the wheel assembly  60   a.  The wheel assembly  60   a  trails the kingpin  72  during the forward travel of the trailer  10 . Thus, the weight of a load on the trailer frame  20  serves to maintain the wheel assembly  60   a  in a trailing relationship relative to the direction of movement of the trailer  10 . When the vehicle  5  is backing, the wheel assembly  60   a  will caster about the kingpin  72 . 
     The trailer frame  20  has affixed to the side beam  22   a  and aligned with the cross bar  25   b  a locking plate  73 . The locking plate  73  includes a center hole  74   a  for receiving kingpin  72 . The exterior side of the locking plate  73  includes an tab portion  73   a  having a locking hole  74   b  formed therein. The center axis of the center hole  74   a  and the center axis of the locking hole  74   b  are essentially aligned and parallel. 
     The horizontal pivoting plate  69  includes two locking tabs  69   a  and  69   b  projecting from the side of the plate  69  and spaced approximately 180 degrees apart. The locking tabs  69   a  and  69   b  have center holes formed therein. When the wheel  61   a  is in a trailing position (FIGS.  1  and  2 ), the hole  74   b  in the locking plate  73  would align with the hole in the locking tab  69   a.  The wheel  61   a  is locked with the receipt of locking pin  77  in the trailing position. When the wheel  61   a  is in a backing position (FIGS.  8  and  9 ), the the hole  74   b  in the locking plate  73  would align with the hole in the locking tab  69   b.  The wheel  61   a  is locked with the receipt of locking pin  77  in the backing position. 
     Referring also to FIG. 10, the wheel  61   a  is designed to pivot about kingpin  72  between the backing position and the trailing position. 
     The wheel assembly  60   a  includes shock absorber  80 . The shock absorber  80  includes a vertical coil spring  85  and an essentially vertical retainer rod  87  having a threaded end  87   a  which is attached to a horizontal plate  69  at groove  89  via washer  91  and bolt  92 . 
     The shock absorber  80  further includes a U-shaped brace  95  having hole  96  for the receipt of the retainer rod  87 . The upward projecting surfaces of the U-shaped brace  95  abut the under side of the horizontal plate  69 . The vertical coil spring  85  is disposed between the underside of the U-shaped brace  95  and the lower end of the retainer rod  87 . In operation, the shock absorber absorbs imparting forces as the result of the arm  64  pivoting about pivot  69 . 
     Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and because many modifications may be made in the embodiment herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.