Patent Publication Number: US-2004052625-A1

Title: Transport trailer having retractable loading ramps and equipment securing system

Description:
RELATED APPLICATIONS  
     [0001] The Applicant claims priority under 35 U.S.C. §119(e) of provisional U.S. Patent Application Serial No. 60/411,186 filed on Sep. 16, 2002. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates generally to wheeled vehicles and transport trailers. In particular, the present invention relates to transport trailers for carrying large agricultural and commercial vehicles, such as spray vehicles, that must be loaded and unloaded frequently.  
       [0004] 2. Description of the Related Art  
       [0005] Heavy farm and industrial equipment and commercial vehicles are often transported using trailers having special loading ramps at the rear end of the trailers to facilitate loading and unloading. During the use of such trailers, a persistent problem has been the difficult and time-consuming task of moving the loading ramps between their raised transport positions and their lowered positions for loading and unloading. This is particularly so in the case of agricultural spray vehicles and the like that must be loaded and unloaded frequently.  
       [0006] For example, large agricultural spray vehicles are commonly used to spray many different fields in remote locations during a single day. At each field location, the loading ramps must be pivoted from their raised positions into their lowered positions to allow the spray vehicle to roll smoothly off the rear end of the trailer onto the ground. After spraying each field, the spray vehicle must then be driven back up the ramps and onto the trailer. Once the vehicle is on the trailer, the ramps must be pivoted back into their raised position and secured in place. The vehicle itself must then be secured to the trailer using cables or chains and suitable tightener devises. In many cases, a “WIDE LOAD” warning sign is also secured into place at the rear of the trailer for highway transport. The trailer, with the spray vehicle secured thereon, is then ready to move to the next field location where the unloading, spraying, and reloading process is repeated.  
       [0007] Various improvements have been proposed to make transport trailers easier to load and unload. For example, U.S. Pat. No. 4,136,791 issued to Clark discloses a transport trailer having a tiltable loading ramp that can be moved between an inclined loading position and a horizontal transport position using a pair of hydraulic rams. U.S. Pat. No. 4,792,274 issued to Cockram discloses a utility trailer having an automatic tailgate assembly that moves from an inclined loading position into a tailgate forming position when the item to be transported contacts a front trigger plate assembly. U.S. Pat. No. 4,372,727 issued to Fredrickson et al. discloses a transport trailer having a powered ramp tail movable in multiple stages between an inclined loading position and a horizontal transport position using hydraulic actuators. U.S. Pat. No. 6,126,223 issued to Rayburn discloses a transport trailer having a tailgate lift assembly that uses a spring-biased cable to raise the tailgate from an inclined loading position into a raised transport position. U.S. Pat. No. 5,145,310 issued to Calzone discloses a reverse spring system to facilitate moving trailer ramps from a transport position into a loading position.  
       [0008] The prior art patents described above provide various systems to facilitate the raising and lowering of loading ramps or tailgates of transport trailers. However, none of these systems include a tie-down mechanism associated with the loading ramps to secure the vehicle being transported to the trailer. These systems also lack a “WIDE LOAD” warning sign that automatically moves between lowered and raised positions with the movement of the loading ramps. Thus, additional time-consuming steps must be taken to secure the vehicle to the trailer using chains or cables and suitable tightening mechanisms, and also to mount a “WIDE LOAD” warning sign behind the trailer after it is loaded. This leads to greater operator fatigue and less productivity for the vehicle and other equipment being transported on the trailer. The prior art systems also lack a structure to stabilize the rear end of the trailer when the loading ramps are in their lowered positions and the vehicle is being loaded and unloaded.  
       SUMMARY OF THE INVENTION  
       [0009] An object of the present invention is to provide a transport trailer having retractable loading ramps and an equipment securing system that are interconnected for more efficient and effective loading and unloading operations.  
       [0010] A further object of the present invention is to provide a transport trailer having a “WIDE LOAD” warning sign that automatically moves between lowered and raised positions upon moving the loading ramps of the trailer between their lowered and raised positions.  
       [0011] It is a further object of the present invention to provide an improved ramp assembly for a transport trailer that can be moved easily between an inclined lowered position and a raised transport position to facilitate frequent loading and unloading operations.  
       [0012] It is a further object of the present invention to provide an equipment securing system having a locking structure that can be engaged automatically to maintain a secure attachment of the equipment securing system to the vehicle being carried by the trailer.  
       [0013] It is a further object of the present invention to provide a transport trailer that can be loaded and unloaded frequently and quickly with little effort, that includes an equipment securing system to facilitate attaching items to the trailer, that automatically displays a “WIDE LOAD” warning sign at the rear end of the trailer after a wide load is positioned on the trailer, and that includes a structure for stabilizing the rear end of the trailer during loading and unloading.  
       [0014] It is a further object of the present invention to provide a transport trailer that is economical to manufacture, efficient in use, capable of a long operating life, and particularly well suited for use in transporting large agricultural spray vehicles and the like.  
       [0015] To accomplish these and other objects, a transport trailer for transporting agricultural vehicles is provided by the present invention. The transport trailer has a platform supported by a plurality of wheels, and a pair of loading ramps to facilitate loading vehicles onto the platform. An operating mechanism is provided for pivoting the loading ramps between raised and lowered positions. The operating mechanism includes an actuator and a J-shaped arm associated with each loading ramp. The J-shaped arm provides a structure for stabilizing the rear end of the trailer during loading and unloading.  
       [0016] According to the present invention, the trailer is also equipped with a plurality of tie down arms to automatically secure the spray vehicle to the trailer when the loading ramps are raised. The operating mechanism that raises and lowers the loading ramps is also used to move the tie down arms. A lock mechanism selectively locks the tie-down arms in their respective lowered positions.  
       [0017] The transport trailer of the present invention also includes a sign having visual indicia, such as the words “WIDE LOAD,” pivotally connected to a rear end of the trailer platform. The sign is interconnected with the operating mechanism that raises and lowers the loading ramps to pivot the sign between lowered and raised positions upon corresponding movement of the loading ramps.  
       [0018] Numerous other objects and advantages of the present invention will be apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of the present invention, simply by way of illustration of one of the modes best suited to carry out the invention. As will be realized, the invention is capable of other different embodiments, and its several details are capable of modification in various obvious aspects without departing from the invention. Accordingly, the drawings and description should be regarded as illustrative in nature and not restrictive. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0019] The present invention will become more clearly appreciated as the disclosure of the invention is made with reference to the accompanying drawings. In the drawings:  
     [0020]FIG. 1 is an elevation view of a transport trailer according to the present invention with a large spray vehicle carried thereon.  
     [0021]FIG. 2 is an elevation view of the transport trailer shown in FIG. 1 with the vehicle in the process of being loaded or unloaded.  
     [0022]FIG. 3 is a plan view of a rear portion of the transport trailer according to the present invention with one loading ramp shown in a lowered position for loading and unloading, and the other ramp shown in a raised position.  
     [0023]FIG. 4 is a side view of one of the loading ramps and a ramp operating mechanism with the ramp in a raised position according to the present invention.  
     [0024]FIG. 5 is a side view of the loading ramp and ramp operating mechanism shown in FIG. 4 with the ramp in a lowered position according to the present invention.  
     [0025]FIG. 6 is a rear view of the transport trailer according to the present invention with the loading ramps and warning sign in raised positions.  
     [0026]FIG. 7 is a rear view of the transport trailer according to the present invention with the loading ramps and warning sign in lowered positions.  
     [0027]FIG. 8 is a front view of a locking mechanism for a tie down system that secures the vehicle on the transport trailer, with the tie down system shown in a locked position.  
     [0028]FIG. 9 is a front view of the locking mechanism of FIG. 8 showing the tie down system in an unlocked position.  
     [0029]FIG. 10 is a perspective view of the operating mechanism for the loading ramps and the tie down system. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0030] A transport trailer  10  having retractable loading ramps and an equipment securing system according to a preferred embodiment of the present invention will now be described with reference to FIGS.  1  to  10  of the accompanying drawings.  
     [0031] The transport trailer  10  includes a platform  11  supported by a chassis  12  and a plurality of wheels  13 ,  14 . A conventional hitch structure  15  is provided at a front side of the trailer  10  for connection to a truck or the like. The platform  11  has right and left side loading areas  16 ,  17  for supporting respective right and left side wheels  18 ,  19  of a large agricultural spray vehicle  20  or other large implement. A front abutment  21  is provided at the front of each of the right and left side loading areas  16 ,  17  to limit forward movement of the vehicle  20  on the trailer  10 .  
     [0032] Right and left side loading ramps  22 ,  23  are provided at the rear of the trailer  10  for facilitating movement of the spray vehicle  20  from the ground surface  24  onto the loading areas  16 ,  17  of the trailer  10 . The loading ramps  22 ,  23  each have first ends  25 ,  26  pivotally connected to a rear portion of the loading areas  16 ,  17  of the trailer  10 , and second ends  27 ,  28  that can be moved into and out of engagement with the ground surface  24 . Each loading ramp  22 ,  23  is movable between a first lowered position (FIGS. 2, 5 and  7 ) for loading and unloading the vehicle  20 , and a second raised position (FIGS. 1, 4 and  6 ) for transporting the vehicle  20 .  
     [0033] In the preferred embodiment, the loading ramps  22 ,  23  are each constructed of a pair of frame members  29 ,  30  extending in the longitudinal direction, and a plurality of transverse members  31  attached between the frame members  29 ,  30 . However, a variety of other construction techniques for the loading ramps  22 ,  23  are also possible and within the scope of the present invention.  
     [0034] An operating mechanism  32  is provided for pivoting the loading ramps  22 ,  23  between their respective lowered and raised positions. The operating mechanism  32  includes a pair of linear actuators  33 ,  34  arranged in a center console  35  of the trailer  10 . In the preferred embodiment, the linear actuators  33 ,  34  are pneumatic bladder-type actuators (i.e., air bags) which are placed on their sides to expand and retract in a longitudinal direction of the trailer  10 . The linear actuators  33 ,  34  each have a first end  36  secured to a stationary part of the trailer  10 , such as the frame or chassis  12 , and a second end  37  connected to a moving bracket  38 . The moving brackets  38  each include a pair of arms  39 ,  40  that extend rearwardly from a front plate  41  and connect to radial extending arms  42 ,  43  on a respective transverse shaft  44 ,  45 . The front plate  41  of each moving bracket  38  is slidably supported on a support shaft  46  using a short tubular member  47  placed over the support shaft  46 . Tension springs  48  are used to bias the linear actuators  33 ,  34  to their retracted positions.  
     [0035] The transverse shafts  44 ,  45  are pivoted independently of each other upon extending and retracting the respective linear actuators  33 ,  34 . Shock absorbers (not shown) or other damping mechanisms can be used in conjunction with the linear actuators  33 ,  34  to restrict the speed of movement of the actuators  33 ,  34 , although in most applications this will not be necessary. The transverse shafts  44 ,  45  are supported at each end to the frame of the trailer  10  by bearings  48 .  
     [0036] The operating mechanism  32  also includes a pair of J-shaped arms  49 ,  50  associated with the loading ramps  22 ,  23 . The J-shaped arms  49 ,  50  each have a first end  51  rigidly connected to a respective one of the transverse shafts  44 ,  45 , e.g., by welding, and a second end  52  pivotally and slidably coupled to a respective one of the loading ramps  22 ,  23 . The J-shaped arms  49 ,  50  are driven by rotation of the transverse shafts  44 ,  45  to move the loading ramps  22 ,  23  between their lowered and raised positions. The J-shaped arms  49 ,  50  are arranged so that they rest on the ground surface  24  and help stabilize the rear end of the trailer  10  when the loading ramps  22 ,  23  are in their down positions, as shown in FIG. 2.  
     [0037] The second ends  52  of the J-shaped arms  49 ,  50  are pivotally and slidably coupled to slotted members  53  that are attached to and extend along the bottom sides of the loading ramps  22 ,  23 . Pin connectors  54  extend through holes formed in the second ends  52  of the J-shaped arms  49 ,  50  and into or through the slots  55  formed in the slotted members  53 . When the J-shaped arms  49 ,  50  are moved by the transverse shafts  44 ,  45 , the pin connectors  54  pivot and slide along the slots  55  in the slotted members  53 . Other construction techniques for pivotally and slidably connecting the J-shaped arms  49 ,  50  to the loading ramps  22 ,  23  can also be used, such as using grooved members or tracks instead of a slotted member.  
     [0038] The trailer  10  has a tie-down mechanism  56  to facilitate securing the spray vehicle  20  to the trailer  10 . The tie-down mechanism  56  includes right and left side tie down arms  57 ,  58  each having first and second ends  59 ,  60 . The first ends  59  of each of the tie down arms  57 ,  58  are rigidly attached, e.g., by welding, to respective right and left transverse shafts  61 ,  62 . The transverse shafts  61 ,  62  are supported at each end by bearings  63  and can be rotated independently of each other. The second ends  60  of each of the tie down arms  57 ,  58  are provided with a loop, hole, hook or other suitable structure for coupling with a flexible connector  64 , such as a link chain. The tie down arms  57 ,  58  are movable between a first raised position (FIG. 5) and a second lowered position (FIG. 4) by rotation of the respective transverse shafts  61 ,  62 .  
     [0039] The flexible connector  64  has one end  65  attached to the tie down arms  57 ,  58  and another end  66  adapted to be attached to a frame or chassis of the vehicle  20  loaded on the trailer  10 . For example, the vehicle  20  can be provided with a slot into which a chain link of the flexible connector  64  can be placed and securely held. When the tie down arms  57 ,  58  are in their raised positions, the flexible connector  64  is loose and can be easily attached or removed from the vehicle. When the tie down arms  57 ,  58  are in their lowered positions, the flexible connector  64  is tightened and kept taut to secure the vehicle  20  to the trailer  10 .  
     [0040] The tie down mechanism  56  is operatively interconnected with the operating mechanism  32  of the loading ramps  22 ,  23  so that movement of the tie down arms  57 ,  58  is synchronized with movement of the loading ramps  22 ,  23 . Tie down actuator links  67 ,  68  are connected to radial extending arms  69 ,  70  on the first transverse shafts  44 ,  45  and extend forwardly to operate the tie down mechanism  56 . Radial arm assemblies  71 ,  72  are connected to each of the second transverse shafts  61 ,  62  and are pivotally connected to the front ends of the tie down actuator links  67 ,  68 . When the linear actuators  33 ,  34  are expanded or contracted to rotate the first set of transverse shafts  44 ,  45 , the tie down actuator links  67 ,  68  transmit the driving force to the second transverse shafts  61 ,  62 . As a result, the tie down arms  57 ,  58  move from their raised positions to their lowered positions when the loading ramps  22 ,  23  move from their lowered positions to their raised positions, respectively. The right side tie down arm  57  moves in sync with the right side loading ramp  22 , and the left side tie down arm  58  moves in sync with the left side loading ramp  23 .  
     [0041] A lock mechanism  73  is provided to positively lock the tie down arms  57 ,  58  in their lowered positions for maintaining the flexible connectors  64  in a taut condition. The lock mechanism  73  has right and left side lock members  74 ,  75  that can be inserted into recesses  76  in the tie down arms  57 ,  58  when the tie down arms  57 ,  58  are in their lowered positions. The lock mechanism  73  includes a linear actuator  77  that automatically moves the lock members  74 ,  75  into their locked positions after the tie-down arms  57 ,  58  are moved into their lowered positions.  
     [0042] The linear actuator  77  is operatively connected to the lock members  74 ,  75  by a toggle arm  78  and linkage assemblies  79 ,  80 . The toggle arm  78  is pivotally attached at a midpoint  81  to a bearing housing  82  or other part of the trailer  10 . The linear actuator  77  is connected to a lower end of the toggle arm  78  for pivoting the toggle arm  78  about its midpoint  81 . When the linear actuator  77  is extended, the toggle arm  78  is pivoted clockwise to cause the sliding lock members  74 ,  75  to engage and lock the tie-down arms  57 ,  58  in their lowered positions.  
     [0043] In the preferred embodiment, the first and second linear actuators  33 ,  34  and the linear actuator  77  are connected in a common pneumatic or hydraulic circuit. The linear actuator  77  operates sequentially with the linear actuators  33 ,  34  to move the lock members  74 ,  75  into their locked positions following movement of the tie-down arms  57 ,  58  into their lowered positions. Similarly, the linear actuator  77  operates to move the lock members  74 ,  75  into their unlocked positions before the tie-down arms  57 ,  58  are moved from their lowered positions to their raised positions.  
     [0044] A sign  82  having visual indicia  83  thereon, such as a “WIDE LOAD” or “OVERSIZE LOAD” warning, is attached to a rear end of the trailer  10 . The sign  82  is pivotally connected along its lower edge  84  to the rear end of the trailer  10  for pivoting movement between lowered and raised positions. In the raised position (shown in FIGS. 1,6 and  10 ), the sign  82  is readily visible to other vehicles following the trailer  10  and does not impede the view of the tail lights  85  of the trailer  10 . However, the sign  82  cannot remain in its raised position while the vehicle  20  is being loaded and unloaded because it blocks the path of the vehicle  20  onto the trailer  10 . By pivoting the sign  82  to its lowered position during loading and unloading, the sign  82  does not block the path of the vehicle  20  onto the trailer  10 .  
     [0045] The sign  82  is interconnected with the operating mechanism  32  such that the sign  82  pivots between its lowered and raised positions upon movement of one of the loading ramps  23  between its lowered and raised positions. A center radial arm  86  extends from one of the transverse shafts  45  for driving the sign  82 . A link  87  is pivotally connected to the center radial arm  86  and extends rearward to a bracket  88  on a back side of the sign  82 . The center radial arm  86  moves the link  87 , and hence, the sign  82 , when the transverse shaft  45  is rotated by the operating mechanism  32 .  
     [0046] While the invention has been specifically described in connection with specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.