Abstract:
A trailer, having the capability of lowering its deck to the ground surface for ease of loading and unloading from the ground; raising its deck to a loading dock height for ease of loading and unloading from a loading dock or other elevated surface; and tilting its deck for dumping is disclosed. The deck is maintained in a transport position for travel. All the changes in position may be effected by a single actuator. Rollers, affixed to a rail affixed to the deck roll inside C-channels affixed to the frame arranged at a diagonal to the vertical when raising or lowering.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a Divisional of U.S. patent application Ser. No. 10/932,410 filed Sep. 2, 2004, entitled HYDRAULIC LEVEL-LOADING AND DUMPING TRAILER, which is incorporated by reference herein in its entirety. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   REFERENCE TO MICROFICHE APPENDIX 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a trailer. More particularly the present invention relates to a trailer providing dumping capabilities and having the additional capabilities of raising for level-loading and unloading at loading docks of various heights and lowering for easy loading and unloading at ground level. 
   2. Background Art 
   Trailers for hauling machinery and other cargo are commonplace. Many trailers available today provide a dumping feature, mostly for effortless unloading of loose cargo such as gravel, sand, soil, etc. 
   For loading and unloading machinery, commonly a machine must be driven up and down ramps to load and unload. Some trailers are made to tilt, much like the dumping feature previously mentioned, for loading and unloading. Most commonly, the cargo hauled by these trailers is fairly light, such as snowmobiles. 
   If a machine or other heavy cargo must be unloaded from a trailer at a loading dock, the elevation of which is much higher than the trailer deck level, significant ingenuity or a serious hoisting operation may need to be exercised to transfer the machine or cargo. 
   A trailer, made to adjust into a low, loading position is disclosed by Stringer in U.S. Pat. No. 6,273,435. The trailer of this patent is capable of being moved from a first or lowered position to a second or elevated position in a substantially vertical or nontilting manner. Truss-like sides, affixed to the trailer deck, provide channels engaging the trailer&#39;s frame. The frame remains at the same level relative to the axle while the deck and truss-like sides raise and lower relative to the axle. This trailer does not have a dumping capability, nor can it be raised to load or unload from a loading dock. The design of this trailer, where the truss-like sides are affixed to the deck, precludes the possibility of raising the deck significantly because the truss-like sides would be required to extend significantly below the deck, and would thus contact the ground. 
   There is therefore a need for a trailer that dumps, lowers into a loading position, and, raises for loading and unloading from a loading dock or other elevated location. There is a further need for a trailer having a structure for raising and lowering the deck that is rigidly affixed to the frame to which the wheels are affixed. 
   BRIEF SUMMARY OF THE INVENTION 
   A first object of the present invention is to provide a trailer, the deck of which tilts to facilitate dumping cargo. A second object of this invention is to provide a trailer deck that lowers to facilitate loading and unloading, especially, but not limited to, wheeled and tracked vehicles and machinery. A third object of this invention is to provide a trailer, the deck of which will raise to a loading-dock height to facilitate loading and unloading at loading docks and other elevated surfaces. Still another object of the present trailer invention is to provide a trailer that combines all the above objects, lending versatility to the trailer so it may be used for hauling loose cargo like gravel, sand, soil, etc., vehicles and machinery that are driven onto the trailer, and that such cargo may be loaded and unloaded at elevated locations such as loading docks. 
   To effect these objects, in a preferred embodiment, the trailer of the present invention is built with diagonal C-channels: a pair near the front of the trailer (front being defined as being toward the tongue used for drawing the trailer), and a pair near the rear of the trailer. (C-channel is steel channel with a cross-section shaped like a “C”, typically with substantially square corners.) In the preferred embodiment, each of these diagonal C-channels is shaped like a “V” laid on its side, a lower leg of the “V” being shorter than an upper leg. The apex of the “V” is at approximately the same height as an upper rail of a railing around the trailer deck. A roller, engaging each diagonal C-channel is attached to the upper rail. In a transport position, each roller engages the diagonal C-channel near the apex. To raise a given end (front or back) of the trailer deck, the pair of rollers attached to the upper rail at that end are forced to travel along the upper legs of the diagonal C-channels at that end of the trailer. To lower a given end of the trailer deck, the pair of rollers attached to the upper rail at that end are forced to travel along the lower legs of the diagonal C-channels at that end of the trailer. Thus, one end of the trailer deck may be raised or lowered independently of the other. All adjustments to the heights of the ends of the trailer deck are carried out using a hydraulic cylinder disposed between a standard attached toward the front of the tongue and the front railing of the trailer. 
   Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a perspective view of a trailer of the present invention carrying a skid loader and drawn by a pickup truck; 
       FIG. 2  is a first side elevation view of the trailer with a deck in a transport position; 
       FIG. 3  is a detail of a diagonal C-channel and linkages for controlling movements of the trailer deck relative to axles of the trailer; 
       FIG. 4  is a detail of a latch for locking the trailer deck in place; 
       FIG. 5  is a second side elevation view of the trailer with the deck in a lower, ground loading position; 
       FIG. 6  is a detail of diagonal C-channels and linkages for controlling movements of the trailer deck relative to axles of the trailer, the linkages being in a position for lowering the trailer deck to the ground loading position; 
       FIG. 7  is a top plan view of a tongue region of the trailer, showing a hydraulic cylinder, valving, pump, and batteries; 
       FIG. 8  is a side elevation view of the trailer with the trailer deck in an upper, loading dock position. 
       FIG. 9  is a detail of diagonal C-channels and linkages for controlling movements of the trailer deck relative to axles of the trailer, the linkages being in a position for raising the trailer deck to a loading dock position; 
       FIG. 10  is a perspective detail view of a torsion axle; 
       FIG. 11  is a cross-sectional detail of the C-channel diagonal member with a roller disposed therein; 
       FIG. 12  is a side elevation view of the trailer with the trailer deck in a tilted, dump position; 
       FIG. 13  is a detail of diagonal C-channels and linkages for controlling movements of the trailer deck relative to axles of the trailer, the linkages being in a position for tilting the trailer deck to a dump position; 
       FIG. 14  is a perspective view of a rear of the trailer showing a rear restraining bar; 
       FIG. 15  is a perspective detail view of a hinged end of the rear restraining bar; 
       FIG. 16  is a detail of a stabilizer foot near the rear of the trailer; and 
       FIG. 17  is a perspective view of a locking mechanism for securing the trailer deck to a trailer frame. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The following is a description of the preferred embodiment of the trailer of the present invention. The invention may be embodied differently than the preferred embodiment. Details of the preferred embodiment are not to be taken as limitations to the present invention, rather, limitations are described in the claims. 
   The trailer  100  of the present invention is shown in perspective in  FIG. 1 . This trailer  100  is made to:
         lower for ease of ground loading and unloading ( FIGS. 5-6 );   raise for ease of loading and unloading at a loading dock or other elevated surface ( FIGS. 8-9 ); and   tilt for dumping ( FIGS. 12-13 ).       

   The trailer  100  is drawn by a source of motive power  105  such as the pickup truck depicted in  FIG. 1 . Other sources of motive power  105  are automobiles, semi tractors, farm tractors, construction equipment, etc. The present invention is not limited to a particular source of motive power  105 . Indeed, a truck bed could be constructed in the manner disclosed, here, and would not be drawn as a trailer is drawn. 
   In  FIG. 2 , a tongue  200  is clearly seen and is provided for attaching the trailer  100  to the source of motive power  105 . The end of the trailer  100  on which the tongue  200  is found is defined as the front of the trailer  100 . The opposite end of the trailer  100  is defined as the rear or back of the trailer  100 . The forward direction of movement is defined as movement toward the tongue  200  of the trailer  100 . Backward or rearward movement is defined as movement away from the tongue  200  of the trailer  100 . 
   The trailer  100  is supported and transported on wheels  110 . Although tandem axles are depicted in the figures, the present invention is not limited thereto. 
   A frame  115  is operatively attached to the wheels  110  via a suspension system. An example of such a suspension system is shown in  FIG. 10  as a torsion axle assembly  1000 . The torsion axle assembly comprises an axle  1010 , a rubber torsion suspension system  1020 , and a connecting lever arm  1030 . 
   Additional support, when needed, is provided by stabilizer feet  120  mounted toward the rear of the trailer  100 . The stabilizer feet  120  are especially useful when the trailer is in its loading dock position (see  FIG. 8 ) because of the high center of gravity, but may be employed any time additional stability is needed. 
   Rigidly attached to the frame  115  are four diagonal C-channels. Two front diagonal C-channels  125  (only one seen in  FIGS. 1 and 2 ) and two rear diagonal C-channels  130 . The front  125  and rear  130  diagonal C-channels need not be identical. 
   Parts of the trailer  100  that move relative to the frame  115  comprise the deck  500  (see  FIG. 5 ), and railings  135 , the railings being rigidly, operatively attached to the deck  500 . The deck  500  is not permanently affixed to the frame  115 , but rather latches onto it with a latch assembly  1700  as seen in  FIG. 17 . The latch  1700  comprises two parts: a frame affixed receiver  1710  and a railing affixed insertion  1720 . 
   Viewing  FIGS. 3 and 11 , inside each diagonal C-channel  125 ,  130 , resides a roller  310  that is operatively, rotatably attached to the trailer railing  135 . 
   The trailer  100  is shown in a transport position in  FIG. 2 . The deck  500  is in the position most used when the trailer  100  is pulled down the road. In  FIG. 3 , a trailer control linkage assembly  300  is shown. A front lever  320  controls the action of the front of the trailer deck  500 . A rear lever  330  controls the action of the rear of the trailer deck  500 . Manipulating either lever  320 ,  330  controls a control flapper  340  on each side of the trailer  100 . The front lever  320  controls two control flappers  340  in the front diagonal C-channels  125  while the rear lever  330  controls two control flappers  610  (see  FIG. 6 ) in the rear diagonal C-channels  130 . The control flappers  340 ,  610  are used to restrict the movement of the rollers  310  to the channel that will provide the action desired. There are two positions for the control flappers  340 ,  610 : an upper position and a lower position. One control flapper  340  is shown in each of these positions in  FIG. 3 . When the control flapper  340  is in the upper position, the roller  310  is disallowed to enter the upper leg of the diagonal C-channel  125 . Therefore, the upper control flapper  340  position is used when lowering the front of the deck  500 . When the control flapper  340  is in its lower position, the roller  310  is disallowed from entering the lower leg of the diagonal C-channel  125 . Therefore, this lower position is used when the deck  500  is to be maintained in the transport position and when the deck  500  is to be raised, in which case the roller  310  follows the upper leg of the diagonal C-channel  125 . When moving from the upper position to the lower position the control flappers  610  are in the down position and vice versa when moving from the lower position to the upper position. The control flappers  610  at the rear of the trailer  100  are controlled in the same way as the front control flappers  340 . The front control flappers  340  are manipulated independently of the rear control flappers  610  because the ends of the trailer  100  may travel in the same direction, or they may travel in opposite directions (e.g. when tilting for dumping). 
   When the trailer  100  is in its transport position, a deck safety latch  400 , as shown in  FIG. 4 , secures the deck  500  in a forward position. In order for the trailer deck  500  to raise or lower from the transport position, the deck  500  must travel backward relative to the frame  115  so that the rollers  310  can remove from the horizontal section of C-channel at the apex of the “V” shaped diagonal C-channels  125 ,  130  and engage one or the other of the legs of the diagonal C-channels  125 ,  130 . The deck safety latch  400  restricts the fore-aft movement of the deck  500  relative to the frame  115 . When a deck safety latch pedal  410  is depressed, the deck safety latch lever arm  420  rotates about an axis of rotation, raising the rear end of the deck safety latch lever arm  420  sufficiently high to allow a pin or other raised portion  430  to escape from a notch or hole in the safety latch lever arm  420 , freeing the trailer deck  500  to move backward relative to the frame  115 . 
   The trailer  100  of the present invention is shown in  FIG. 5  with the deck  500  in its lowered, ground loading position. In this position, vehicles may easily be driven on or off the trailer  100  because the deck  500  is nearly flush with the ground or pavement. Cargo may be loaded or unloaded with a fork lift, again made easier by the very low level of the deck  500 . Other cargo may be loaded more easily due to reduced lifting. 
   The stabilizer feet  120  (only one shown in  FIG. 5 ) are shown in their lowered position to add stability to the trailer  100  during loading and unloading. In particular, the rear portion of the trailer  100  is less likely to tip down when the weight of the cargo is behind the wheels  110 . Side to side stability is also improved when the stabilizer feet  120  are lowered. If the trailer  100  is not attached to a source of motive power  105 , a jack  510  is provided to support the front end of the trailer  100  near or at the tongue. 
   Motive force to change the deck&#39;s  500  position is derived from an actuator  210  such as a hydraulic cylinder. When in the transport position, the actuator  210  is in a retracted position such as seen in  FIG. 2 . When the deck  500  is in either its upper or lower positions, the actuator  210  will be in an extended position as seen in  FIGS. 5 and 8 . 
   The detail in  FIG. 6  shows how the levers  320 ,  330  are adjusted to permit the lowering of the deck  500 . The front control flappers  340  and the rear control flappers  610  are in their upper positions, permitting the rollers  310  (operatively, rotatably attached to the railings  135 ) to travel down the lower leg of the diagonal C-channels  125 ,  130 , thus lowering the deck  500  to which the railings  135  are operatively, rigidly attached. The arrows in  FIG. 6  show the direction of travel of the rollers  310  during lowering of the deck  500 . 
   In  FIG. 7 , the front of the trailer  100  is shown from above. The actuator  210  is clearly seen in this view and is retracted into the transport position. In the preferred embodiment, the actuator  210  comprises a hydraulic cylinder. An electric hydraulic pump  710  is used to provide high pressure hydraulic fluid with which to actuate the actuator  210 . A set of hydraulic control valves  720  are provided for manual operation of the actuator  210  as well as the stabilizer feet  120 . Energy to operate the hydraulic pump  710  is provided by batteries  730 . Through a conventional wiring for the lights of the trailer the alternator from the prime mover will charge the battery when the trailer is being transported. 
   The deck  500  is shown in the upper, loading dock position in  FIG. 8 . The stabilizer feet  120  (only one shown in  FIG. 8 ) and the jack  510  are again shown in their lowered positions. 
   The detail of  FIG. 9  shows how the levers  320 ,  330  are manipulated to permit the deck  500  to be raised to its loading dock position. The control flappers are placed in their lower position, permitting the rollers  310  to travel in the direction of the arrows into the upper leg of the diagonal C-channels  125 ,  130  when the actuator  210  is actuated from its retracted position ( FIGS. 1 and 7 ) to its extended position as shown in  FIG. 8 . 
   The trailer  100  is shown in its tilted, dump position in  FIG. 12 . In  FIG. 13 , the appropriate manipulation of the levers  320 ,  330  is shown. The front control flapper  340  is placed in its lower position so the front rollers  310  are permitted to travel up the upper leg of the front diagonal C-channel  125 . The rear control flapper  610  is placed in its upper position so the rear rollers  310  are permitted to travel down the lower leg of the rear diagonal C-channel  130 . In this way, the front of the deck  500  is raised relative to the wheels  110  while the rear of the deck  500  is lowered relative to the wheels  110 . 
   A safety bar  1410  is shown in  FIGS. 14 and 15  extending between the tops of the left and right railings  135  at the rear of the trailer deck  500 . The safety bar  1410  pivots on a horizontal pin  1510  so it may be raised off a first pin  1420  in order to rotate around a vertical pin  1430  to swing out of the way for loading and unloading. The entire safety bar  1410  may be lifted off both pins  1420 ,  1430  and removed completely, if desired. 
   A detailed view of one stabilizer foot  120  is shown in  FIG. 16  in its lowered position. The stabilizer foot  120  is actuated by a stabilizer foot actuator  1610  which, in the preferred embodiment, is a hydraulic cylinder. The stabilizer foot actuator  1610  is actuated by manipulating a hydraulic control valve among the set of hydraulic control valves  720 . When in its upper position, the stabilizer foot  120  is held close to the trailer frame  115  to avoid damage while the trailer is in motion. 
   To maintain the trailer deck  500  in its transport position and take the load off the rollers  310  when in the transport position, a latch assembly  1700  as shown in  FIG. 17  is used. The latch assembly  1700  comprises two parts: a frame  115  affixed to receiver  1710  and a deck  500  affixed to insertion  1720 . This arrangement is so that the frame will not spread when you turn a corner. 
   Note that, although not shown, the deck  500  of the trailer  100  may also be made to tip forward, that is, the front of the deck  500  may be made to lower while the rear of the deck  500  is made to raise. 
   The above embodiment is the preferred embodiment, but this invention is not limited thereto. It is, therefore, apparent that many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.