Abstract:
A hydraulic tail trailer comprising a main deck having a main tail assembly pivotally connected to the rearward end thereof with the pivotal connection therebetween being located forwardly of the centerline of the rear axle of the trailer suspension system. The location of the hinge between the main deck and the main tail assembly, by being located forwardly of the centerline of the rear axle, provides a main tail having an increased length thereby providing a lower loading angle without increasing the overall length of the trailer. The trailer of this invention also enables the front axles of the trailer suspension system to be moved to multiple spread positions with respect to the rear axle.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a hydraulic tail trailer including a front axle supported on a front suspension system and a rear axle supported on a fixed rear suspension system and more particularly to a hydraulic tail trailer wherein the main tail thereof is hingedly connected to the trailer frame forward of the centerline of the rear axle. Even more particularly, this invention relates to a hydraulic tail trailer wherein the front axle thereof is selectively longitudinally movable to multiple positions with respect to the fixed rear axle to enable the trailer to carry additional weight as the spacing of the front axle with respect to the rear axle is increased. 
     2. Description of the Related Art 
     The trailer transportation of heavy or large farm and industrial equipment requires special loading ramps at the rear end of the trailer. A typical hydraulic tail trailer of the prior art includes a rear axle supported on a rear suspension system and a front axle supported on a front suspension system. The rear axle and rear suspension system is sometimes referred to as a rear running gear assembly. The front axle and front suspension system is sometimes referred to as a front running gear assembly. In most prior art trailers, the rear and front suspension systems are longitudinally fixed to the trailer frame such as shown in U.S. Pat. No. 7,547,178 which is owned by the assignee of the instant invention. In some cases, both the rear and front suspension systems are slidably mounted, as a unit, on the trailer frame such as shown in U.S. Pat. No. 5,013,056. In other prior art trailers, the rear axle may be moved forwardly on the trailer frame for unloading and loading purposes only such as disclosed in U.S. Pat. No. 5,215,426 which is also owned by the assignee of the instant invention. 
     In U.S. Pat. No. 7,547,178, the location of the hinge between the main deck and the main tail assembly is located forwardly of the centerline of the rear axle to provide a main tail having an increased length thereby providing a lower loading and unloading angle without increasing the overall length of the trailer. However, in U.S. Pat. No. 7,547,178, the spacing of the rear and front axles is fixed. Thus, the weight which may be legally carried by the trailer of U.S. Pat. No. 7,547,178 is fixed and cannot be increased since axle spacing determines the weight which may be legally carried by a trailer. 
     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. 
     A hydraulic tail trailer is disclosed which includes a main frame having forward and rearward ends with the main frame including at least first and second longitudinally extending side frame members. Longitudinally extending first and second running gear beams, having forward and rearward ends and upper and lower ends, are secured to the main frame in a fixed non-movable manner. Each of the first and second running gear beams have rearwardly extending portions which extend rearwardly from the rearward end of the main frame. The trailer also includes front and rear axles having first and second ends with wheels being secured to the first and second ends of the front and rear axles. A front suspension assembly selectively longitudinally adjustably secures the front axle to the first and second running gear beams forwardly of the rearward end of the main frame in multiple longitudinal positions with respect to the main frame. A rear suspension assembly secures the rear axle to the first and second running gear beams rearwardly of the rearward end of the main frame in a single longitudinal non-movable position. 
     A main deck is mounted on the main frame and has forward and rearward ends. The rearward end of the main deck is positioned forwardly of the centerline of the rear axle and is positioned rearwardly of the centerline of the front axle. The trailer also includes a hydraulically operated tail assembly, having forward and rearward ends, with the forward end of the tail assembly being pivotally secured to the main deck at the rearward end of the main deck. The pivotal connection of the forward end of the tail assembly to the rearward end of the main deck is positioned forwardly of the centerline of the rear axle and is positioned rearwardly of the front axle in all of the multiple positions of the front axle. The front axle is selectively longitudinally movable to multi-positions to increase or decrease the spacing between the front and rear axles thereby enabling the legal carrying weight of the trailer to be increased by increasing the spacing between the front and rear axles. 
     In the preferred embodiment a front axle brake is operatively coupled to the wheels on the front axle and a rear axle brake is operatively coupled to the wheels on the rear axle with the front and rear axle brakes being independently operable. In the preferred embodiment, the tail assembly includes a main tail, having a rearward end, a forward end, an upper end, and a lower end. The tail assembly further includes a flip tail, having a rearward end, a forward end, and a lower end, with the forward end of the flip tail being pivotally secured to the rearward end of the main tail. The flip tail is selectively movable from a stowed position beneath the main tail to a position wherein the flip tail is parallel to the main tail. 
     It is therefore a principal object of the invention to provide an improved hydraulic tail trailer. 
     A further object of the invention is to provide an improved hydraulic tail trailer which includes front and rear axles with the front axle being selectively longitudinally movable to multiple positions to enable the spacing between the front and rear axles to be increased thereby increasing the legal carrying weight of trailer. 
     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 with the broken lines illustrating a position to which the wheels on the front axle may be positioned; 
         FIG. 2  is a perspective view of the trailer of this invention which illustrates the front axle thereof being in its forwardmost position with the tail assembly being in its extended loading and unloading position; 
         FIG. 3  is a top view of the trailer of  FIG. 1 ; 
         FIG. 4  is a side view of the trailer of  FIG. 1  with the front axle being in its rearwardmost position; 
         FIG. 5  is a partial top view of the main frame and running gear beams of the trailer of this invention; 
         FIG. 6  is a partial side view illustrating the tail assembly in its horizontally disposed position and with the front axle of the trailer being in its rearwardmost position; 
         FIG. 7  is an enlarged partial view of the structure of  FIG. 6 ; 
         FIG. 8  is a partial side view of the trailer of this invention with the front axle being positioned just rearwardly of its forwardmost position; 
         FIG. 9  is a view similar to  FIG. 8  except that the front axle has been moved forwardly to its forwardmost position; 
         FIG. 10  is a partial side view illustrating the manner in which the tail assembly is operated; 
         FIG. 11  is a view similar to  FIG. 10  except that the tail assembly is in its extended loading and unloading position; 
         FIG. 12  is a partial front perspective view of the air operated locking means which is associated with the front axle suspension system of this invention; 
         FIG. 13  is a partial end view of one of the locking pin assemblies of this invention; 
         FIG. 14  is a partial side view illustrating the manner in which the front axle suspension system is secured to one of the running gear beams of the trailer; 
         FIG. 15  is a partial front view of the front axle suspension system and the front axle; 
         FIG. 16  is a partial center line sectional view of one of the running gear beams with front and rear suspension systems secured thereto; 
         FIG. 17  is a view similar to  FIG. 16  except that the front suspension system has been moved forwardly with respect to the rear suspension system; and 
         FIG. 18  is a view similar to  FIG. 17  except that the front suspension system has been moved forwardly from the position of  FIG. 17 . 
     
    
    
     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 hydraulic tail trailer of this invention is referred to generally by the reference numeral  10  and includes a forward end  12  and a rearward end  14 . Trailer  10  may include a conventional upper deck section  16  and a hydraulically operated upper deck ramp  18  of conventional design. A king pin  20  is provided at the underside of the forward end of the trailer to enable the trailer to be connected to a prime mover such as a truck having a fifth wheel assembly mounted thereon. 
     Trailer  10  includes a wheeled frame means  22  having first and second main frame beams  24  and  26  which are interconnected by cross-members  27  in conventional fashion such as shown in U.S. Pat. No. 7,547,178, which issued on Jun. 16, 2009 the disclosure of which is incorporated by reference thereto to complete this disclosure if necessary. The numeral  30  refers to a main deck which is supported upon the main frame beams  24 ,  26  and the cross-members extending therebetween with the main deck  30  having a forward end  32  and a rearward end  34  ( FIGS. 1 and 2 ). A pair of longitudinally extending and horizontally spaced-apart running gear beams  36  and  37  are secured to the frame means  22  between the main frame beams  24  and  26  with each of the beams  36  and  37  having rearwardly extending portions  36 A and  37 A. Each of the running gears  36  and  37  are provided with a step or shoulder  41  at the forward ends of the rearwardly extending portions  36 A and  37 A to accommodate a hinge  42 . 
     The numeral  44  refers to a hydraulic tail assembly, as disclosed in U.S. Pat. No. 7,547,178, which is pivotally secured to the rearward end of main deck  30  by hinge  42  and which includes a main tail  46  and a flip tail  48 . Main tail  46  is provided with a deck  50  positioned thereon. The rod ends of hydraulic cylinders (not shown) are pivotally connected to the underside of main tail  46  for moving the main tail  46  from its load carrying position ( FIG. 1 ) wherein the deck  50  is parallel to main deck  30  to a second position wherein main tail  46  extends upwardly and rearwardly from main deck  30  ( FIG. 10 ) to a third position wherein main tail  46  extends downwardly and rearwardly relative to main deck  30  ( FIG. 2 ). 
     Rip tail  48  is hingedly connected at its forward end  52  to the lower rearward end of main tail  46  by hinge  54 . A hydraulic cylinder (not shown) is pivotally connected to and extends between the main tail  46  and flip tail  48  for pivotally moving flip tail  48  from a stowed position beneath the rearward end of main tail  46  ( FIG. 1 ) to an operative position so that the upper deck surface  56  of flip tail  48  is parallel to and in alignment with the deck  50  of main tail  46 , as disclosed in U.S. Pat. No. 7,547,178. Generally conventional locking means is provided for maintaining flip tail  48  in its stowed position ( FIG. 1 ). Further, means is provided for maintaining main tail  46  in its load carrying position of  FIG. 1 , as disclosed in U.S. Pat. No. 7,547,148. 
     The numeral  58  refers to the rear suspension system of this invention which is the same as disclosed in U.S. Pat. No. 7,547,178. Rear suspension system  58  is fixedly secured to the rearward end portions  36 A and  37 A of running gear beams  36  and  37  respectively. Rear suspension system  58  includes a rear axle  60  having wheels  62  secured to the opposite ends thereof. Rear axle  60  is positioned rearwardly of the forward end of main tail  46 . A conventional brake system is connected to the rear suspension system  58  for braking the wheels  62 . 
     The numeral  64  refers to the front suspension system of this invention which is selectively longitudinally movably secured to the running gear beams  36  and  37  forwardly of the rearward end of main deck  30 . Front suspension system  64  includes a front axle  66  having wheels  68  secured to the outer ends thereof. System  64  includes horizontally disposed and generally rectangular frame  70  having a forward end  72 , a rearward end  74 , and sides  76  and  78 . An air tank  80  is mounted on the forward end of frame  70  which is in communication with a source of pressurized air. An elongated and longitudinally extending slider frame member  82  is mounted on frame  70  at side  76 . An elongated and longitudinally extending slider frame member  84  is mounted on frame  70  at side  78 . 
     Frame  70  has a pin support  86  mounted on the side of slider frame member  82 . Pin support  86  includes a pin cage  87  positioned therein with the pin cage  87  having a horizontally extending bore extending therethrough. An elongated locking pin  90  is horizontally slidably movably received in the bore formed in pin cage  87  and has an outer end  92  and an inner end  94 . The inner end  94  of pin  90  has the outer end of an elongated link  96  pivotally secured thereto by bolt or pin  98 . The inner end of link  96  is pivotally secured to one end of crank arm  100  by bolt or pin  102 . Crank arm  100  is mounted on a rotatable shaft  104 , as seen in  FIG. 12 . The other end of crank arm  100  has an elongated link  106  pivotally secured thereto by bolt or pin  108 . The outer end of link  106  is pivotally secured to the inner end of locking pin  110  which is selectively horizontally movably mounted in pin support  112 . Pin support  112  is the mirror image of pin support  86  and includes a pin cage  113  through which the locking pin  110  extends. 
     An air diaphragm actuator  114  is mounted on frame  70  as seen in  FIG. 12  and has an actuator shaft  116  extending therefrom. The inner end of shaft  116  is pivotally secured to a crank arm  118  by bolt or pin  119 . Crank arm  118  is fixedly secured to the shaft  104  as seen in  FIG. 12 . 
     The air diaphragm actuator  114  is connected to air tank  80  by suitable piping. A conventional controller (not shown) is connected to air diaphragm  114  for extending and retracting shaft  116 . The extension of shaft  116  causes crank arm  118  to rotate in a counterclockwise direction as viewed from the front of the front axle suspension system  64  thereby rotating shaft  104  in the counterclockwise direction. The rotation of shaft  104  in the counterclockwise direction causes links  96  and  106  to be moved inwardly thereby causing the locking pins  90  and  110  to be moved inwardly with respect to pin supports  86  and  112  respectively to an unlocked position. Conversely, the retraction of shaft  116  causes the locking pins  90  and  110  to be moved outwardly from the pin supports  86  and  112  respectively to a locked position. 
     Front suspension system  64  also includes a pin support  120  at the rearward end of frame  70  rearwardly of pin support  112 . Pin support  120  includes a locking pin  122  which is operatively connected to the rearward end of shaft  104  for simultaneous movement with locking pins  90  and  110 . Front suspension system  64  also includes a pin support  124  at the rearward end of frame  70  rearwardly of pin support  86 . Pin support  124  includes a locking pin  126  which is operatively connected to the rearward end of shaft  104  for simultaneous movement with locking pins  90 ,  110  and  122 . 
     The front suspension system  64  is mounted on the trailer frame so that the slider frame members  82  and  84  slidably receive the lower flanges of running gear beams  36  and  37  respectively. When so mounted, the pin supports  86  and  124  will be positioned adjacent the inner side of the web of the running gear beam  36  and the pin supports  112  and  120  will be positioned adjacent the inner side of the web of the running gear beam  37 . In the rearwardmost position of  FIGS. 1 and 7 , the locking pin  126  of pin support  124  will be received by the rearwardmost opening  128  in running gear beam  36  and the locking pin  90  of pin support  86  will be positioned in a forward opening  128 . At that same time, locking pins  110  and  122  of pin supports  112  and  120  will be received by openings  130  in running gear beam  37 . When it is desired to increase the distance or spread of front suspension system  64  with respect to rear suspension system  58 , the air diaphragm actuator  114  will be actuated to withdraw the locking pins from the openings  128  and  130 . The brake on the front suspension system  64  will be engaged to lock the wheels thereof. The trailer  10  will then be moved rearwardly by the truck so that the trailer  10  and the rear suspension system  58  are moved rearwardly with respect to the stationary front suspension system  64  until the proper spacing or spread between the front and rear suspension systems has been reached. 
     The air diaphragm actuator  114  is then operated to move the locking pins  90  and  126  into the proper openings  128  in running gear beam  36  and to simultaneously move the locking pins  110  and  122  into the proper openings  130  in running gear beam  37 . As seen, the front suspension system  64  is selectively movable to multiple positions with respect to rear suspension system  58 . 
     As stated above, the legal load limit of the trailer  10  may be increased by increasing the spread of the front and rear axles. The ability to increase the spread of the front and rear axles in combination with the hydraulic tail structure of U.S. Pat. No. 7,547,178 results in a truly unique trailer which represents a distinct improvement in the hydraulic tail trailer art. 
     Thus it can be seen that the invention accomplishes at least all of its stated objectives. 
     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.