Abstract:
A heavy load transport vehicle which has the ability of transforming from a flat-bed trailer into a multiple-automobile transporter, having a hydraulic-powered retractable upper deck; hydraulic-powered lift arms that are designed to allow the vehicle to transport wide loads and to be loaded from the side of the lower deck; a stabilizer system which minimizes or eliminates lateral movement of the vehicle during operation on the road; a truss assembly that is designed to synchronize the action of the hydraulic-powered lift arms; and a cable pulley system which assists in the raising of the front end of the upper deck.

Description:
TECHNICAL FIELD 
     The present invention relates generally to heavy load transport vehicles and more particularly to a heavy load transport vehicle having a hydraulic-powered retractable upper deck. 
     BACKGROUND OF THE INVENTION 
     Transport vehicles known in the art for transporting automobiles and other heavy loads generally comprise a lower deck and an upper deck which is held above the lower deck by means of fixed posts. In the past, such vehicles required use of a suitable ramp in order to mount loads onto the upper deck. Loading the upper deck became easier with the development of transport vehicles having an upper deck capable of being raised and lowered by hand operated or power operated devices. In many of these types of vehicles, the upper deck is vertically movable along support posts extending from opposite sides of the lower deck. These support posts limit the width of the load which may be carried when the upper deck is in the lowered position. Also, for those transport vehicles, where the load to be carried on the upper deck is mounted on the upper deck while the deck is in the lowered position, the support posts may restrict the width of the load capable of being carried on the upper deck. Furthermore, the support posts may make it difficult, if not impossible, to load the decks from either side of the vehicle. 
     The ability to carry wider loads is significant. Transport vehicles that provide only for the hauling of automobiles, for example, may at times be economically prohibitive. In the case of a transporter who delivers a load of cars to a designated location, the inability to load anything other than cars onto the transport vehicle may require the transporter to make the return trip with no load to be hauled. 
     The transport vehicles known in the art which have a vertically movable upper deck may be unsafe when heavy loads are mounted upon the raised upper deck. This is because at the high speeds typically reached while driving on the highway, the upper deck may be subject to lateral movement and shaking. This could compromise the vehicle driver&#39;s ability to safely maneuver the vehicle. Furthermore, this instability could potentially lead to damage to the load being hauled or damage to the vehicle over time. 
     Also, a number of transport vehicles known in the art have two vertically spaced decks with a hydraulically-powered means for raising and lowering the upper deck. These vehicles often encounter problems in the operation of the plurality of hydraulic lifts which raise and lower the upper deck. In particular, these vehicles commonly have problems raising and lowering the upper deck uniformly, with all of the hydraulic lifts raising and lowering in a synchronized manner. This problem could lead to maintenance problems as well as pose a safety hazard as a heavy load carried on the upper deck could potentially fall off the vehicle if the upper deck is raised or lowered unevenly. More importantly, such a system that lacks the means to synchronize the raising and lowering of the hydraulic cylinders would require a powerful and costly driving means for actuating the hydraulic cylinders. 
     Trailers generally known in the art are also limited by height restrictions imposed by federal and state Department of Transportation regulations relating to vehicle height. In the fully retracted position, with the upper deck in the lowered position, the transport vehicle may carry a load upon the upper deck. However, the total height of the load must be sufficiently low to allow travel under bridges and overpasses and to otherwise comply with federal and state regulations. The design limitations of the trailers generally known in the art do not allow the upper deck to be positioned low enough to comply with statutory height restrictions while carrying such loads. 
     SUMMARY OF THE INVENTION 
     The main object of the present invention is to overcome the above disadvantages of the transport vehicles known in the art. According to the present invention there is provided a load transporting vehicle comprising a lower deck having a set of wheels near the rear portion of said vehicle and a means for supporting the front portion of the lower deck located at the front end of the lower deck; an upper deck; and a means by which the upper deck is supported above the lower deck and by which the upper deck is adjusted between a raised, unretracted position and a lowered, fully retracted position, comprising a plurality of single-action hydraulic cylinders which are each pivotably connected at one end to the lower deck via a hydraulic cylinder lower mounting pin and pivotably connected at the other end to a lift arm via an upper hydraulic cylinder bracket, a plurality of lift-arms which are each pivotably connected at one end to the lower deck and pivotably connected at their other end to the hydraulic cylinder, a stabilizer track system that is mounted to the lower deck and guides the upper deck in a vertical up and down motion and prevents the upper deck from moving in a direction transversely of the vehicle longitudinal axis. 
     The present invention achieves the objective of allowing wide loads to be carried upon the upper deck when the upper deck is in the fully retracted, lowered position, by virtue of its elimination of the need for support posts to raise and lower the upper deck. The present invention&#39;s upper deck stabilizer system and the design of its lifting mechanism eliminate the need for support posts, thereby allowing wider loads to be hauled upon the upper deck while it is in the lowered position. 
     The present invention also achieves the objective of raising and lowering the upper deck with the lift arms being actuated in a synchronized manner. This is accomplished by virtue of a truss assembly, comprising a plurality of braces that run perpendicular to the direction of travel of the vehicle and connect each pair of lift arms at the point where the lift arms are connected to the upper deck, and a series of trusses that extend across the vehicle diagonally and connect the cross braces. 
     The objective of transporting loads, such as conversion vehicles, on the fully retracted upper deck is achieved by virtue of the present invention&#39;s design which provides for the height of the fully retracted upper deck to be 42″ above the surface upon which the vehicle travels. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is now made to the drawings which illustrate the best known mode of carrying out the invention and wherein the same reference numerals indicate the same or similar parts throughout the several views. 
     FIG. 1 is a perspective side view of the present invention with the upper deck in the raised position. 
     FIG. 2 is a rear view of the present invention&#39;s lift arm unit. 
     FIG. 3 is a perspective side view of the present invention&#39;s upper deck track roller system. 
     FIG. 4 is a perspective side view of the present invention&#39;s upper deck stabilizer system. 
     FIG. 5 is a side view of the present invention&#39;s lifting mechanisms, one in the “down” position when the upper deck is lowered, and one in the “up” position when the upper deck is raised. 
     FIG. 6 is a side view of the present invention&#39;s cable pulley system. 
     FIG. 7 is a top view of the present invention&#39;s lift arm synchronizing truss assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a perspective side view of the present invention which is a load transporting vehicle. More specifically, the present invention is a trailer having two platforms, an upper deck  1  and a lower deck  2 , upon which heavy loads may be placed for hauling. The rear portion of the lower deck  2  is supported by a set of at least four road wheels  3  (only 2 are shown) located toward the rear of the transport vehicle, relative to the direction of travel. Located at the front end of the lower deck  2  is a means  4  by which the lower deck  2  is detachably connected to a conventional means for towing the load transporting vehicle, such as a truck. Alternatively, the front end of the load transporting vehicle may have a conventional driving means which is capable of driving or propelling the vehicle in the desired direction. 
     As shown in FIG. 1, the upper deck  1  is positioned above the lower deck  2  and is supported by a plurality of lift arms  5 , which are preferably constructed of steel. Each lift arm  5  is pivotably connected at one end to the lower deck  2  and pivotably connected at its other end to a hydraulic cylinder  6 . FIG. 2 shows how each pivot point, where the lift arms  5  are connected to the lower deck  2 , may advantageously be comprised of two identical pieces of flat steel  7  which have a hole bored through each and are attached to the lower deck  2 , and a steel pin  8  which is positioned such that it travels through the holes in the identical pieces of flat steel  7  and through the lift arm  5 , thus pivotably securing the lift arm  5  at its lower pivot point. 
     As shown in FIG. 3, each lift arm  5  is slidably connected to the upper deck  1  by an upper deck  1  track roller system. At the end of each the lift arm  5 , opposite the end where the lift arm  5  is pivotably connected to the lower deck  2 , there is provided a flat piece of steel  9  welded to the lift arm  5  upon which a steel roller  10  is welded. The steel rollers  10  roll along the length of a track  11  which spans the length of each side of the upper deck  1 . As the lift arms  5  are actuated to lift the upper deck  1 , the end of each lift arm  5  that is slidably connected to the upper deck  1 , rolls along the length of the track  11  until preferably the lift arm  5  is roughly perpendicular to the plane of the lower deck  2 . Conversely, the end of each lift arm  5  rolls along the track  11  in the opposite direction as the upper deck  1  is lowered. 
     FIGS. 1 and 4 show a stabilizer track system which is preferably comprised of two vertical guide posts  12  which are mounted perpendicularly to the lower deck  2 . Each guide post  12  has a vertical track  13  that runs along the entire length of the guide post  12 ; sealed bearing steel rollers  14  which are mounted to the upper deck  1  and roll along the vertical track  13  of the guide posts  12 ; and a stabilizer trussing  15  secured to the lower deck  2  and the guide posts  12 . This system is designed to guide the upper deck  1  in a vertical up and down motion above the lower deck  2 . This system also secures the upper deck  1  and prevents the upper deck  1  from moving in a direction transversely of the vehicle longitudinal axis. An additional stabilizer system may be advantageously added to the rear portion of the load transporting vehicle to further stabilize the upper deck  1 . 
     As shown in FIGS. 1 and 5, a plurality of hydraulic cylinders  6  are each pivotably connected to the lower deck  2  by a lower cylinder  6  pivot bolt  16  and pivotably connected to a lift arm  5  by an upper cylinder pin  17 . These hydraulic cylinders  6  are double-action cylinders driven by a self-contained hydraulic pump located in close proximity to the trailer axes that connect the wheels  3  of the lower deck  2 . The self-contained hydraulic pump operates using battery power from at least one battery that is advantageously charged by the towing device or driving means for propelling the load transporting vehicle. The hydraulic cylinders  6  are actuated to cause the lift arms  5  to lower or raise the upper deck  1 . 
     The raising and lowering of the front end of the upper deck  1  is aided by a cable pulley system, shown in FIG.  6 . The cable pulley system includes a plurality of pulleys  19  that are mounted upon the outer edges of the upper deck  1  at each side of the vehicle, two lifting pulleys  20 A (only one shown) that are each bolted to one of the guideposts  12  of the stabilizer track system, and two pulleys  20 B (only one shown) mounted upon the outer edges of the lower deck  2  at each side of the vehicle. The pulleys  19 ,  20 A,  20 B each have a grooved rim along which two cables  18  run across. The cables  18  weave through the series of pulleys  19 ,  20 A,  20 B. The lifting pulleys  20 A reverse the pulling power of the cables  18  to lift the front end of the upper deck  1  at the rate the lift arms  5  raise the upper deck  1 . One end of each cable  18  is advantageously bolted to the loading surface or the outer edges of the upper deck  1  near the front of the trailer preferably by a turn buckle type bolt  21 A which provides for adjustment as the cables  18  stretch over time. The other end of each cable  18  is advantageously bolted to the underneath or to either of the outer edges of the upper deck preferably by another turn buckle type bolt  21 B. The exact same configuration of pulleys and a cable is found, although not shown, on the opposite side of the vehicle shown in FIG.  6 . 
     The plurality of lift arms  5  and hydraulic cylinders  6  are actuated in a synchronized manner, which is made possible by the truss assembly shown in FIG.  7 . As can be seen in FIG. 7, the truss assembly is comprised of a plurality of cross braces  22  that extend across the underside of the upper deck  1 , in the direction perpendicular to the direction of travel of the vehicle, and a plurality of trusses  23  that extend across the underside of the upper deck  1  diagonally and connect the cross braces  22 . The plurality of trusses  23  may advantageously be secured by being welded to bushings  24  that encompass the cross braces  22 . Each of the cross braces  22  connects a lift arm  5  to a corresponding lift arm  5  positioned on the opposite side of the vehicle. The cross braces  22  also stabilize the lift arms  5 , thereby preventing the steel rollers that are bolted to the lift arms  5  from coming out of the tracks that span the length of each side of the upper deck  1 . As the upper deck  1  is raised and lowered, the lift arms  5  will be actuated in a synchronized manner because the truss assembly connects each lift arm  5 , making it impossible for any one lift arm  5  to extend or retract without causing the others to synchronously extend or retract to the same extent. The truss assembly likewise causes the hydraulic cylinders  6  to be actuated in unison because the hydraulic cylinders  6  are connected to the lift arms  5  and, thus, move at the same rate as the lift arms  5 . The synchronization of the cylinders  6  efficiently distributes the power necessary to lift the upper deck  1 , which in turn, makes it possible for the upper deck  1  to be raised even when its height is less than 42″ above the ground in the fully retracted, lowered position. 
     Other objects, features and advantages will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited except as required by the scope of the appended claims.