Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation of U.S. application Ser. No. 11/286,654 filed Nov. 23, 2005, which application is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention generally pertains to trailers and specifically to trailers designed for a tight turning radius. 
     Prior art trailers have been designed which provide a tight turning radius; however, these trailers use complicated structures to turn the trailer&#39;s wheels. 
     U.S. Pat. No. 1,600,635, issued to Isachsen on Sep. 21, 1926, shows an arrangement of a frame 11, and a steering rod 7 independent of the frame 11. The steering rod 7 is fastened to crank arm 3, then secured to a knuckle joint 4, and connected to a second knuckle joint 4′ using arms 5 and a connecting bar 8. This complicated structure functions to turn the wheels 10. 
     U.S. Pat. No. 2,450,215 issued to Wilson on Sep. 28, 1948, uses multiple arms and steering links 29 and 14. This complicated structure functions to turn the wheels 24. 
     U.S. Pat. No. 2,092,683, issued to Stidham on Sep. 7, 1937, shows a non-conventional system using parallel cable 32 and a draw frame system 21. These two systems must operate together in order to turn the wheels 14. 
     The above-subject patents are all structures which function to permit the wheels to turn on stub axles. Unfortunately, each is a complicated structure and includes multiple moving parts. 
     Therefore, there is a need to produce a simplified structure with fewer moving parts to reduce costs associated with manufacturing, tooling and assembly. 
     Additionally, the complicated structures limit the amount of weight that may be placed upon them. Accordingly, it is a still further objective of the present invention to provide a trailer that may have a high maximum payload for hauling a great amount of weight associated with farm products such as spray tanks, fertilizer, and seed. 
     These and other objectives will become apparent from the following specification and drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     The foregoing objectives may be achieved using a tow behind steerable caddy trailer having a main frame assembly having opposite ends, a wheel pivotally attached to each end of the main frame assembly, a pair of swinging arms pivotally attached to the main frame assembly and extending forward from the main frame. The swinging arms are spaced apart from one another such that each swinging arm is positioned adjacent a wheel. The swinging arms can be maintained parallel or non-parallel to one another. The trailer has a support structure attached to the main frame assembly that can support a platform, tank, hopper, etc. Additionally, it has been contemplated that tracks could be used in place of the wheels for supporting platforms, tanks and hoppers exceeding the weight limits for a wheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a tow behind steerable caddy. 
         FIG. 2  is a top view of the tow behind steerable caddy. 
         FIG. 3  is a side view of the tow behind steerable caddy. 
         FIG. 4  is a rear view of the tow behind steerable caddy. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to  FIGS. 1-4 , numeral  10  refers to a tow behind steerable caddy. The tow behind steerable caddy trailer  10  is designed to follow behind a tractor, an implement pulled by a tractor, or other vehicle. 
     The trailer  10  is designed to follow in the tracks of the towing vehicle to navigate tight turning radiuses. The tow behind steerable caddy trailer  10  thus may negotiate tight turning radiuses in a field with very few end rows or with equipment that has a very narrow operating width. 
     The steerable caddy trailer  10  has a main frame assembly  12  illustrated as a metal square tube. The main frame assembly  12  has opposite ends  14 , a top side  16 , a bottom side  18 , a front side  20 , and a back side  22 . Angled end caps  26  are attached at each end  14  of the main frame assembly  12 . It has been contemplated that the end caps  26  could also be a vertical end cap rather than an angled end cap  26 . A vertical end cap may be used in conjunction with a track or in applications requiring additional structural strength to support heavy loads. 
     A spindle assembly  28  is pivotally attached at each end  14  of the main frame assembly  12 . The spindle assembly  28  has a base plate  30  and a top plate  34  connected by an angled extension  36  which ends in a vertical surface with a spindle  40  for a wheel  44 . The base plate  30  and top plate  34  are attached to the angled end cap  26  by a pivot pin  42 . The spindle assembly has a vertical support  38  which strengthens the connection of the base plate  30  and the top plate  34  to strengthen the spindle assembly  28 . 
     A forward base member  32  is provided to extend from the base plate  30  and has a hole for connecting a first end of a tie rod  70 . 
     Swinging arms  46  extend from the main frame assembly  12 . Each swinging arm member  46  has a rear end  48  that pivotally attaches to the main frame assembly  12 . The rear end  48  has a top support  50  and a bottom support  52 , which extends above and below the main frame assembly  12  to pivotally attach to a cylinder  54  at the back side  22  of the main frame assembly  12  by a pivot pin  61 . The bottom support  52  also has a hole for receiving a front end of tie rod  70 . A front end  58  of the swinging arm members  46  has an adapter  60  for attaching to a rigid cross member, such as the exemplary rigid cross member shown in  FIG. 1  in dashed lines. The rigid cross member could be a piece of square tubing (as shown). The rigid cross member could also be a bumper, a vehicle, a tractor or other farm implement. It is preferred that the swinging arm members  46  be pivotally mounted to a rigid cross member. For example, attaching a hitch to the adapter  60  and a ball to both ends of the rigid cross member (as shown in  FIG. 1  in dashed lines) allows the swinging arm members  46  to pivot about the balls. Similarly, swinging arm members  46  could also be pivotally attached to a bumper or another rigid cross member as part of a farm implement. 
     In  FIG. 1 , the swinging arm members  46  are shown parallel to each other and the tires  44  are shown perpendicular to the main frame assembly  12 . However, the swinging arm members  46  need not be parallel to each other for the trailer  10  to steer. Adjusting the swinging arm members  46  affects the turning radius of the steerable caddy trailer  10 . Regardless of the configuration, whether the swinging arm members  46  are parallel or moved inward closer to each other, the tie rods  70  can be adjusted to keep the tires perpendicular to the main frame assembly  12 . 
     A platform support  62  is provided that has side supports  64  and a front support  66  connecting the two side supports  64  and sub-platform supports  68 . The platform support  62  balances the weight of a platform, tank, hopper or other evenly towards the front and back of the main frame assembly  12 . 
     In operation, the caddy is pulled behind the implement and/or vehicle by pivotally connecting the swinging arm members  46  to a rigid cross member. Should the towing vehicle or farm implement turn left this will simultaneously cause the left swinging arm  72  to shift rearward toward the main frame assembly  12  and the right swinging arm  74  to shift forward away from the main frame assembly  12 . Shifting the left swinging arm  72  rearward towards the main frame assembly causes the tie-rod linkage  70  to move the spindle assembly such that the left wheel  76  steers right. Similarly, shifting the right swinging arm  74  forward away from the main frame assembly causes the tie-rod linkage  70  to move the spindle assembly such that the right wheel  78  steers right, also. Thus, when the towing vehicle turns left the wheels  44  on the steerable caddy  10  turn right so as to track the towing vehicle. 
     Should the towing vehicle or farm implement turn right this will simultaneously cause the left swinging arm  72  to shift forward away from the main frame assembly  12  and the right swinging arm  74  to shift rearward toward the main frame assembly  12 . Shifting the left swinging arm  72  forward away from the main frame assembly causes the tie-rod linkage  70  to move the spindle assembly such that the left wheel  76  steers left. Similarly, shifting the right swinging arm  74  rearward toward the main frame assembly causes the tie-rod linkage  70  to move the spindle assembly such that the right wheel  78  steers left, also. Thus, when the towing vehicle turns left the wheels  44  on the steerable caddy  10  turn right so as to track the towing vehicle. 
     In either instance after the towing vehicle turns left or right and returns to driving a straight course, the wheels  44  return to a position perpendicular to the main frame assembly  12 . In this fashion, the steerable caddy trailer is maintained in virtually the same turning radius as the vehicle and/or implement. 
     The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.

Technology Category: b