Abstract:
A directional side dump trailer having a wheeled frame for supporting a containment tub for receiving material to be dumped, which tub is releasably attached to the frame by locks, and at least a pair of power cylinders secured to the tub and the trailer and located generally below the containment tub.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates in general to dump trailers having a containment tub that can be emptied from either of its sides rather than from its rear end and more specifically relates to a lift system for the tub that is designed to better distribute pressure being exerted on the tub ends during the dumping process. 
   2. Description of the Prior Art 
   Bidirectional side dump trailers that include a pivotally mounted containment tub to permit dumping of a load from either side of a trailer rather than the trailer rear end have been known in the prior art for many years and have achieved acceptance in the marketplace since the early 1990&#39;s. Such trailers are particularly useful in situations such as during road construction when it is often necessary to dump numerous large loads of rock or gravel along the sides of roadbeds or for conducting ground leveling activity. 
   A variety of different types of bidirectional side dump trailers are known in the art. An example of one of the earlier types of side dump trailers used commercially is disclosed in U.S. Pat. No. 5,480,214 issued to Rogers. To provide for pivotal movement of the containment tub for dumping purposes, the Rogers&#39; patent discloses the employment of hydraulic powered cylinders at the front and rear of the tub that when engaged cause the tub to pivot to one side or the other to dump material contained therein. 
   Although the Rogers&#39; type of lifting system for the trailer tub has proved useful, it suffers from a number of deficiencies. Firstly and most importantly, by having the powered cylinders located at opposite ends of the containment tub, the lifting force applied, is placed upon the ends of the tub body as it is pivoted to one side or another by the cylinders, rather than being distributed along the length of the body. Secondly, the application of pressure on the ends of the containment tub often results in tub corner cracking as a result of the localization of lifting pressure thereon. Thirdly, the Rogers&#39; design does not allow for the use of containment tubs that are longer than the trailer frame and, in many instances, it is beneficial to be able to use longer tubs when the hauling of maximum loads is required. 
   As an alternative to the Rogers&#39; trailer design, lift systems for the containment tub have been developed that are positioned directly beneath the tub intermediate its end to provide a centrally directly lifting force oh the tub. Two such lift systems are disclosed in U.S. Pat. Nos. 5,906,417 and 5,597,211 issued to Golden. 
   Each of the Golden embodiments involve a centrally disposed, powered, multi-stage cylinder arrangement that lies beneath the containment tub such that as it is actuated the tub is tilted to one side or the other depending upon the dumping action desired. 
   Although the embodiments disclosed by Golden seem to eliminate the deficiencies of having end located power cylinders, as pointed out in the &#39;211 patent, in column 10 due to the use of a single connection point between the lift system and the container tub, the stress on the base wall of the containment tub is extreme and requires further structural strength for the tub. The present invention is adapted to provide a bidirectional side dump trailer that avoids the deficiencies of having end mounted power cylinders or that have only a single centrally located lift system. 
   In view of the foregoing structure, it is an object of the present invention to provide a bidirectional side dump trailer with a lifting mechanism that distributes the lift force over a greater area to allow the associated stresses applied on the container tub to be minimized. Such distribution of the lift force presents the option to use lighter weight material (such as aluminum) in the containment tub ultimately providing greater payloads. It is a further advantage of the present invention to provide a lifting mechanism that requires a relatively low volume of hydraulic fluid for controlling the lift system. It is an additional object of the invention to provide a mechanism that not only allows for the possibility of a greater dump angle for the container tub, but also serves to locate the hydraulic cylinders of the lift mechanism in a location where they are protected beneath the containment tub. 
   SUMMARY OF THE INVENTION 
   The present invention provides a bidirectional side dump trailer for hauling material that is suitable for dumping from either side of the trailer. The invention includes a wheeled frame, a containment tub mounted upon tub supports secured to the frame, locking means located on the tub and the trailer for releasable securement of the tub to the trailer and tub lifting means comprised of at least two power cylinders located at a generally medial location underneath the containment tub. 
   In a preferred embodiment, the power cylinders each have lower ends pivotally secured to a generally medial portion of said trailer and upper ends pivotally secured to the bottom of said containment tub so that the cylinders define a front power cylinder and a rear power cylinder generally in alignment with one another. The wheeled frame includes a plurality of transverse support struts extending between the opposite sides thereof, and the bottom ends of the power cylinders are secured to at least one of the support struts of said frame. 
   The foregoing and other advantages of the present invention will appear from the following description. In the description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by illustration and not of limitation a specific form in which the invention may be embodied. Such embodiment does not represent the full scope of the invention, but rather the invention may be employed in a variety of other embodiments and reference is made to the claims herein for interpreting the breadth of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front-side perspective view of a preferred embodiment of the bidirectional side dump trailer of the present invention formed of a trailer and a containment tub; 
       FIG. 2  is another perspective view of the embodiment of  FIG. 1 , but showing the containment tub being dumped; 
       FIG. 3  is a side view of a cutoff portion of the embodiment of  FIG. 1  and with portions of the trailer cut away to show a pair of power cylinders that form a lift system utilized for dumping of the containment tub; 
       FIG. 4  is an exploded view in perspective of a universal joint assembly for attaching one end of one of the power cylinders to the frame; 
       FIG. 5  is a cross-sectional view taken through the line  5 — 5  of  FIG. 3 ; and 
       FIG. 6  is a perspective view similar to that of  FIG. 2 , but showing a modified embodiment to that of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings and with reference first to  FIG. 1 , a preferred embodiment of the bidirectional side dump trailer of the present invention is shown at  10  that is particularly adapted for hauling rock, dirt, gravel and other types of solid material. The trailer  10  includes a wheeled frame  12  on which is pivotally mounted a containment tub  14 . The wheeled frame  12  is formed from two spaced apart main sidewalls  16  and  18  that are secured together by a plurality of transverse support struts  20 . Although the frame  12  is depicted as being adapted for being pulled by a truck, it should be understood that the frame  12  could also be part of the truck if desired or towed by farm tractor via a hitch. 
   The containment tub  14  has an elongated body  28  including a front wall  30 , a rear wall  32  and an arcuate shaped trough  34  formed with side portions  36  and  38  and a bottom portion  40 . The trailer body  28  has an open top  42  through which materials to be hauled can be loaded into the tub  14 . It should be known to those skilled in the art that although the tub  14  is illustrated with an arcuate body portion, a variety of different types of containment tub shapes are known and are available in the marketplace. Consequently, the specific configuration of the tub  14  is not a critical element of the present invention. 
   The containment tub  14  is supported on the trailer frame  12  by front and rear pairs of saddle assemblies  46  and  48  respectively that serve as forward and rear tub supports. Referring now to  FIG. 5 , each of the saddle assemblies  46  and  48  is formed with a cradle member  50  secured to the frame  12  in alignment with locking pins  52  mounted on the side portions  36  and  38  of the trailer body trough  34 . The locking pins  52  are sized for being received within the cradle members  50  when the tub  14  is supported upon the frame  12 . 
   The saddle assemblies  46  and  48  further include arcuately shaped locking figures  45 , as best shown in  FIG. 5 , that are adapted to be pivotally mounted on the cradles  50  in such fashion that when they are in a closed position, they overlie the locking pins  52  to secure the tub  14  to the frame  12  and when they are in an open condition, they allow the pins  52  to be moved out of the cradles  50 . Thus, the locking pins  52  and locking fingers  54  serve as locking means for releasably securing the tub  14  to the frame  12 . It should be noted that the specific configuration of the saddle assemblies  46  and  48  is not a critical feature of the present invention as there are a wide variety of different types of saddle assemblies known in the art and the specific form of assembly shown herein is merely for purposes of illustration. Additionally, the locking pins  52  can be provided on the frame  12  and the locking fingers  54  can be provided on the tub  14  as an obvious alternative. 
   As illustrated in  FIG. 2 , dumping of the containment tub  14  to either side of the frame  12  is accomplished by selecting the particular saddle assemblies  46  and  48  associated with the side of the tub body  28  that is opposite the side to which dumping is desired, and then moving the locking fingers  54  associated with such assemblies into an open condition to release the locking pins  52 . By releasing the locking pins  52  on only one side of the tub  14  in such fashion, as the tub  14  is then raised it will pivot about the saddle assemblies  46  and  48  that remain in a closed condition so that the tub  14  will be pivoted onto its side and will dump the material it is carrying. 
   To provide for lifting and pivoting of the containment tub  14  with respect to the frame  12 , a lift system  56 , as best shown in  FIG. 3 , is located beneath a generally medial portion of the containment tub  14 . The life system  56  is formed of a pair of preferably hydraulically powered cylinders  60  and  62 . As further illustrated in  FIG. 3 , a base end  64  of each of the cylinders  60  and  62  is secured to a centrally located support strut  58  of the trailer frame  12  by means of lower U-joint assemblies  66  associated with each of the base ends  64 . 
   Each of the cylinders  60  and  62  is directed on an incline with respect to the frame  12  and containment tub  14 , with the front cylinder  60  extending in a forwardly direction so that its ram end is attached to the tub bottom  40  by means of a first upper U-joint  68 . Similarly, the rear cylinder  62  is positioned on an incline in a rearwardly direction to attach to the tub bottom  40  by a second upper U-joint  68 . The use of the U-joints  66  and  68  is preferable to provide for optimum lifting of the container tub  14  in a fashion to accommodate the pivotal movement of the tub  14  with respect to the trailer frame  12 . As is well-known, a U-joint is designed to provide for pivotal movement about two axes and the U-joints  66  and  68  are designed for this purpose. However, other types of connectors may also be used in place of the U-joints  66  and  68  so long as a sufficient pivotal freedom of movement is provided so that damaging twisting or tortional pressures between the cylinders  60  and  62  and the tub  14  are avoided. It should also be noted that the cylinders  60  and  62  do not have to be attached to the central support strut  58  and instead can be positioned away from such strut on either end of trailer frame  12 . Furthermore it would also be possible to utilize two power cylinders  70  and  72  (see  FIG. 6 ) that extend toward one another with their bases spaced further apart than are their attachment points to the tub  14 . 
   As best shown in  FIG. 4 , each of the lower universal joint assemblies  66  is formed with brackets  76  that are secured to the central support strut  58  in a spaced apart relationship for receiving a lower cylinder yoke assembly  78 . Included in the yoke assembly  78  is a head portion  80  with two wedge shaped spaced apart ears  82  extended from one side and with two spaced apart arms  84  extended from the opposite side. 
   Apertures  88  are formed in the brackets  76  and apertures  90  are formed in the yoke assembly ears  82  for receipt of a clevis pivot pin  92  to pivotally secure the ears  82  to the brackets  76  for rotational movement about the pin  92 . Likewise, the base ends  64  of the cylinders  60  and  62  terminate in sleeves  98  that are sized to fit between the yoke assembly arms  84  and are connected thereto by bolts  100  to allow for pivotal movement of the cylinders  60  and  62  thereabout. In a similar fashion to the construction of the U-joints  66 , the U-joints  68 , include pivot pins  102  and bolts  104  about which pivotal movement is permitted between the ram ends of the cylinders  60  and  62  and the container tub  14 . 
   It can thus be seen that the present invention, provides a bidirectional side dump trailer that improves on the prior art structures with a lift system positioned at opposite ends of the container tub or with a single lift system that is located at a point central of the tub. In contrast to such structures, the present invention provides an efficient and unique lift system for the container tub that-applies a lifting force at two different positions on the tub that are somewhat equally spaced apart along the tub bottom to avoid applying widely spaced apart torsional forces on the tub ends. Likewise, the utilization of two-points of contact for applying the lifting pressure on the tub divides up this pressure so that no one portion of the tub is exposed to the total lifting pressure. 
   The foregoing description of the present invention is solely for illustrative purposes only. It is to be understood that the terminology that has been used herein is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. For example, there are many different alternatives for the construction of the container tub  14  or of the wheeled frame  12 . Also, a variety of different types of U-joint constructions would as well be possible and the specific type of construction disclosed for the components of the present invention are only one example of the type of structures that could be utilized. Therefore, the foregoing description is not to be taken as definitive of the scope of the invention; but rather that which is regarded as the invention is set forth in the following claims.