Abstract:
An all-wheel steer trailer is disclosed which includes front and rear axle beams which are pivotally mounted, above vertical axes, to the forward and rearward ends of a frame. In normal operation, the front and rear axle beams are interconnected so that the rear axle beam will pivot in an opposite direction to pivotal movement of the front axle beams so that the rear wheels of the trailer will track the front wheels of the trailer as the trailer is being turned. The trailer includes a convenient locking assembly which may be quickly utilized to prevent pivotal movement of the rear axle beam with respect to the frame when it is desired to pull the trailer on a highway or roadway.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority date of Sep. 14, 2009 relating to the provisional application Ser. No. 61/276,590. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an all-wheel steer trailer and more particularly to an all-wheel steer trailer which is ideally suited for use in the agriculture industry to support fertilizer tanks or the like thereon. Even more particularly, the trailer of this invention includes a mechanism interconnecting the front and rear axle beams on the trailer so that the front and rear wheels will track one another. Even more particularly, this invention relates to a locking assembly which prevents the rear axle beam of the trailer from pivoting with respect to the main frame when the front axle beam is pivoted so that the trailer may be towed on a highway or the like without the rear wheels tracking the front wheels. 
     2. Description of the Related Art 
     Dual axle trailers have long been provided wherein the front axle beam and the rear axle beam are pivoted in opposite directions relative to a main frame when the front axle beam is pivoted in one direction or another so that the rear wheels track the front wheels. An all-wheel steer trailer is disclosed in U.S. Pat. No. 7,571,916. In most all-wheel steer or four-wheel steer trailers, the front and rear axle beams are interconnected by means of a diagonally extending tie rod to cause the simultaneously pivoting of the front and rear axle beams in opposite directions. A problem exists in the art in that when the trailer is to be towed on a road or highway, there is no convenient way of preventing the pivotal movement of the rear axle beam which makes it somewhat hazardous for the trailer to be moved along a road or highway. 
     SUMMARY OF THE INVENTION 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter. 
     An all-wheel steer trailer is disclosed which includes a substantially horizontally disposed frame having a forward and rearward end, a left side and a right side. The trailer includes a transversely extending front axle beam having wheels mounted at the opposite ends thereof. A forwardly extending hitch is secured to the front axle beam and extends forwardly therefrom for connection to a towing vehicle or another agricultural implement such as a tool bar or the like. The front axle beam is pivotally secured, about a vertical axis and a horizontal axis, to the frame at the forward end thereof. The trailer also includes a transversely extending rear axle beam, having first and second ends, which is pivotally secured about a vertical axis to the frame at the rearward end thereof. Wheels are rotatably secured to the opposite ends of the rear axle beam. A lower horizontally disposed plate is fixedly secured to the rear axle beam at the pivotal connection of the rear axle beam to the frame. An upper horizontally disposed plate is fixedly secured to the frame above the lower plate. An intermediate horizontally disposed plate is positioned between the lower and upper plates. The trailer also includes an elongated tie rod having forward and rearward ends with the forward end of the tie rod being pivotally secured, about a vertical axis, to the front axle beam inwardly of the first end thereof. The rearward end of the tie rod is pivotally secured about a vertical axis, to the intermediate plate. A vertically disposed king pin extends through the lower, intermediate and upper plates to pivotally secure the rear axle beam to the frame. 
     The trailer includes a locking assembly which is mounted on the rear axle beam and which is selectively movable between first and second positions. The locking assembly, when in its first position, interconnects the rear axle beam to the intermediate plate whereby pivotal movement of the front axle beam in a first direction with respect to the frame will cause the rear axle beam to pivotally move with respect to the frame in a direction opposite to the first direction. The locking assembly, when in its second position, is disengaged from its connection to the intermediate plate and is interconnected to the upper plate to prevent pivotal movement of the rear axle beam with respect to the frame when the front axle beam is pivoted with respect to the frame by the hitch. 
     In the preferred embodiment, the front and rear axle beams are length adjustable. Also, in the preferred embodiment, a safety mechanism is provided which prevents the locking assembly from moving from its second position. 
     It is therefore a principal object of the invention to provide an improved all-wheel steer trailer. 
     A further object of the invention is to provide a trailer of the type described wherein a locking means is provided for conveniently locking the rear axle beam of the trailer in a position where it cannot pivotally move with respect to the frame of the trailer. 
     A further object of the invention is to provide a trailer of the type described which is convenient to use. 
     These and other objects will be apparent to those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  is a rear perspective view of the trailer of this invention; 
         FIG. 2  is a top elevational view of the trailer of this invention, with the broken lines illustrating the mariner in which the hitch, front axle beam and rear axle beam are pivotally moved; 
         FIG. 3  is bottom perspective view of the rear end of the main frame and the upper plate secured thereto as well as the intermediate plate; 
         FIG. 4  is an exploded perspective view of the locking mechanism mounted on the rear axle beam; 
         FIG. 5  is a side elevational view of the rear end of the trailer illustrating the locking mechanism; 
         FIG. 6  is a perspective view illustrating the locking mechanism; and 
         FIG. 7  is a rear perspective view illustrating the locking mechanism in a first position with the broken arrow illustrating the pivotal movement of the locking handle. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense in that the scope of the present invention is defined only by the appended claims. 
     The trailer of this invention is referred to generally by the reference numeral  10 . Trailer  10  includes a generally horizontally disposed frame  12  having a forward end  14 , a rearward end  16 , a left side  18  as viewed from the rear, and a right side  20  as viewed from the rear. Trailer  10  includes a length adjustable front axle beam  22  having wheels  24  and  26  secured to the ends thereof. Hitch or tongue  28  has its rearward end pivotally secured, about a transverse horizontal axis, to framework  30  which is secured to front axle beam  22  and which extends forwardly therefrom. The numeral  32  refers to a yoke which is pivotally secured to front axle beam  22 , about a horizontal axis, by a pivot pin  34  so that the ends of front axle beam  22 , and the wheels secured thereto, may move upwardly and downwardly with respect to yoke  32  to compensate for irregular or uneven terrain. A horizontally disposed plate is secured to the upper end of yoke  32  by welding or the like. 
     The forward end of frame  12  has a horizontally disposed plate  38  welded to the underside thereof which is movably positioned on the plate on yoke  32 . A vertically disposed pivot pin or king pin  40  pivotally connects the plate on yoke  32  and plate  38  to enable the front axle beam  22  to pivot with respect to the forward end of frame  12 . The forward end of a tie rod  42  is pivotally secured, about a vertical axis, to front axle beam  22  at  44  and extends diagonally rearwardly therefrom. 
     The numeral  46  refers to a length adjustable rear axle beam having wheels  48  and  50  rotatably mounted on the ends thereof. A horizontally disposed lower plate  52  is welded to the top of rear axle beam  46  at the center thereof. A horizontally disposed intermediate plate  54  is rotatably positioned on plate  52  and has a bar or arm  56  extending laterally and upwardly therefrom. The rearward end of tie rod  42  is pivotally connected, about a vertical axis, to the outer end of bar  56  by bolt or pin  58 . Pivot or king pin  60  extends vertically upwardly through rear axle beam  46  and extends upwardly through plates  52  and  54  and through the horizontally disposed upper plate  62  which is welded to the lower end of yoke  64 . 
     The upper end of yoke  64  is secured to the rearward end of frame  12  by welding or the like. The rearward end of plate  54  has a pair of horizontally spaced-apart lugs  66  and  68  welded thereto which extend downwardly from the underside thereof. The rearward end of plate  62  has a generally U-shaped channel  70  having a base portion  72  and ends  74  and  76  which extend forwardly from base portion  72  to form a forwardly facing pocket. 
     Support  78  is welded to rear axle beam  46  and extends rearwardly therefrom. A pair of horizontally spaced-apart collars  80  and  82  are welded to the rearward end of support  78  and have a shaft  84  mounted therein in a fixed manner. Collar or sleeve  86  is rotatably mounted on shaft  84  between collars  80  and  82  and has a tubular member  88  welded thereto which extends transversely downwardly therefrom. A spring retainer pin  90  is positioned in tubular member  88  with its lower end protruding from the lower end of tubular member  88 . One end of a spring  92  is connected to the lower end of pin  90 . 
     The numeral  94  refers to a locking handle assembly which is pivotally or rotatably mounted on the rear end of a support  96  which is welded to rear axle beam and which extends rearwardly therefrom. Locking handle assembly  94  includes leg portions  98 ,  100 ,  102  and  104 . Locking handle assembly  94  also includes a pivot pin  106  which extends downwardly therefrom at the juncture of leg portions  98  and  100  and which is pivotally received by tube  108 , the upper end of which is welded to the rearward end of support  96 . A washer  110  embraces the exposed lower end of pin  106  and is held in place by cotter key  112 . A bracket  114  extends upwardly from the end of leg portion  98  and has the other end of spring  92  secured thereto. 
     A rectangular bar  116  is welded to sleeve  86  and extends therefrom. The length of bar  116  is such that it may be received in the pocket between the ends  74  and  76  of channel  70  and able to be received between lugs  66  and  68 . 
     When the locking handle assembly is in its second position, the tension in spring  92  causes the sleeve to be rotated with respect to shaft  84  so that bar  116  is received within channel  70  so that yoke  64  is “locked” to rear axle beam  46  which prevents any pivotal movement of rear axle beam  46  with respect to frame  12  as indicated by broken lines in  FIG. 5 . Pivotal movement of front axle beam  22  with respect to frame  12  does not cause any pivotal movement of rear axle beam  46  since the rearward end of the tie rod  42 , which is connected to plate  54 , simply causes plate  54  to freely pivot with respect to rear axle beam  46 . 
     When the locking handle assembly is in its first position, as illustrated in  FIG. 5 , the tension in spring  92  causes the sleeve  86  to rotate with respect to shaft  84  which causes bar  116  to be pivotally pulled or moved forwardly between the lugs  66  and  68  on plate  54  to unlock the bar  116  from channel  70  and to cause plate  62  to be locked to the plate  52 . In this position, pivotal movement of front axle beam  22  with respect to frame  12  causes plate  52  to pivot or rotate due to its connection to the tie rod  42 . Pivotal movement of plate  54  will cause rear axle beam  46  to pivot with respect to frame  12  in a direction opposite to the movement of front axle beam  22  due to the fact that plate  54  is locked to plate  52  which is fixedly secured to the rear axle beam. 
     Bar  116  will be selectively locked to plate  52  when the trailer is being used in the field. Bar  116  will be selectively locked to the stationary plate  62  when the trailer is being towed on a highway or the like so that it will trail properly. 
     A safety mechanism is preferably provided which is referred to generally by the reference numeral  118 . Safety mechanism  118  includes a flat plate  120 , one end of which is welded to sleeve  86 . The outer end of plate  120  is provided with an opening  122  formed therein. Safety mechanism  118  also includes a flat plate  124 , one end of which is welded to collar  80 . A spring loaded plunger  126  is secured to the plate  124  and is adapted to be received in opening  122  in plate  120  when bar  116  is received within channel  70  to further ensure that rear axle beam  46  will not inadvertently pivotally move with respect to frame  12  when the trailer  10  is being towed on a highway or the like. 
     Although the invention has been described in language that is specific to certain structures and methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and/or steps described. Rather, the specific aspects and steps are described as forms of implementing the claimed invention. Since many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.