Abstract:
A trailer safety device is provided having two attachment legs that are mounted to frame rails of a towing vehicle. The attachment legs are mounted behind a hitch using U-bolts. The legs continue rearward of the vehicle and meet to form a catch. Failure of the hitch causes a trailer kingpin to become disengaged from the towing vehicle and travel rearward. Rearward travel of the trailer will cause the kingpin to become ensnared on the catch.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/808,388, filed Apr. 4, 2013, the disclosures of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Towable trailers are frequently coupled to a vehicle by a fifth-wheel trailer hitch. Such hitches have been used for decades. In the typical case, a fifth-wheel hitch is mounted on a pair of parallel rails, with the rails in turn mounted to the frame of the vehicle. The fifth-wheel hitch is typically located above, or forward of, the vehicle&#39;s rear-most axle. A trailer used with a fifth-wheel hitch includes a kingpin downwardly extending from the front portion of the trailer. The kingpin is coupled to the fifth-wheel hitch at a keyhole slot in the hitch by an articulating jaw. The jaw extends around the kingpin so as to prevent movement of the kingpin out of the keyhole slot. The articulating jaw is composed of mechanical parts which allow it to move between a locked and an unlocked position to allow the trailer to be coupled and uncoupled from the towing vehicle. As with any mechanical part, the articulating jaw is subject to mechanical failure. A typical towing vehicle has no safety mechanism which holds the trailer to the towing vehicle in the case of an articulating jaw failure. When a vehicle and trailer are traveling, failure of the articulating jaw generally results in the trailer coming loose from the vehicle, and can result in significant injury to person and property. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention relates to a safety device which serves as a safety mechanism to hold a trailer to a vehicle in the case of a fifth-wheel hitch failure. The safety device is U-shaped and includes a pair of mounting arms for securing the safety device to a vehicle. The safety device spans between, and extends rearwardly from, the mounting arms and the base of the “U” serves as a catch where the kingpin will be retained in the event the kingpin is detached from the articulating jaw of the fifth-wheel hitch while the vehicle is in motion. If the hitch fails and the kingpin disengages, the trailer is allowed to slide rearward and become completely detached. A detached trailer from a tractor is frequently a destructive event which can easily become deadly if the tractor-trailer is in motion. Due to the significant mass of a loaded trailer and the potentially deadly outcome from a detached moving trailer, it is desirable to have a backup safety device on the tractor to keep the trailer from becoming completely detached. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    A preferred embodiment of this invention has been chosen wherein: 
           [0005]      FIG. 1  is a rear perspective view of the safety device affixed to a tractor; 
           [0006]      FIG. 1A  is a side cutaway view of a trailer and king pin; 
           [0007]      FIG. 2  is a close-up perspective view of the safety device of  FIG. 1 ; 
           [0008]      FIG. 3  is a top view of the safety device of  FIG. 2 ; 
           [0009]      FIG. 4  is a side view of the safety device of  FIG. 2 ; 
           [0010]      FIG. 5  is a side view of the invention as it is installed on a tractor trailer; 
           [0011]      FIG. 6  is a side view of the invention with the trailer being retained by the safety device of the present invention; and 
           [0012]      FIG. 7  is a partial section view  7 - 7  of the invention as installed on the tractor. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]    Referring to  FIG. 1 , the safety device  10  is defined by a first mounting arm  12 , a second mounting arm  14 , and a catch  16  spaced therebetween. Mounting arms  12 ,  14  are for mounting safety device  10  to a vehicle  26 . Each mounting arm  12 ,  14  has a series of notches  30  that are cut into the sides opposite each other. The notches  30  can be seen in  FIGS. 2 and 3 . Each mounting arm  12 ,  14  is connected to the funneling portions  19 ,  23 . Together, the mounting arms  12 ,  14 , funneling portions  19 ,  23  and catch  16  are U-shaped. The mounting arms  12 ,  14 , and catch  16 , and funneling portions  19 ,  23  are formed as a unitary object. The left mounting arm  12  is connected to the left funneling portion  19 . The right mounting arm  14  is connected to the right funneling portion  23 . 
         [0014]    As described herein, the vehicle  26  has a forward end in the direction of a front bumper of the vehicle, and a rearward end in the direction of a trailer  43  which is towed behind the vehicle. As such, any reference herein to forward or rearward is relative to the forward or rearward ends of vehicle  26 . In the typical configuration, fifth wheel trailer hitch  28  is mounted above the rear axle(s) of vehicle  26 . Hitch  28  is secured to the frame  32  of the vehicle, forward of the device  10 . In the typical configuration a pair of parallel rails  34 ,  35  are secured to the frame  32  of vehicle  26 , with the hitch  28  mounted on the rails. Rails  34 ,  35  each include a series of spaced apertures  36  along the length of the rails which allow hitch  28  to be mounted to rails  34 ,  35  which in turn are mounted to frame  32 . The safety device is mounted to a vehicle  26  that is a truck, semi or similar vehicle which includes a fifth wheel trailer hitch  28 . The hitch  28  is mounted forward of the safety device  10  as is shown in  FIG. 1 . The frame  32  of the vehicle  26  includes frame rails  37 ,  39  made of C-shaped beams. The frame rails  37 ,  39  have inwardly pointed flanges  45  on opposite sides. As depicted in  FIG. 1 , the left frame rail is  37  and the right frame rail is  39 . 
         [0015]    The notches  30  are adapted to receive U-bolts  17  that straddle the frame rails  37 ,  39 . The U-bolts  17  mate with a retention bar  18 , as shown in  FIG. 7 , which receive the clamping force of nuts  20  tightened onto U-bolts  17 . The mounting arms  12 ,  14  are wider than the flanges  45  on the frame rails as is shown in  FIG. 7 . The notches  30  are cut into the sides of the mounting portions such that the distance between the deepest part of opposing notches are similar to the width of the frame rail as shown in  FIG. 7 . The flanges  45  could be bent if too much clamping force is produced from tightening the nuts  20  onto the U-bolts  17 . Braces  21  are placed between the flanges  45  adjacent to the U-bolts  17 . Each brace  21  has an upright piece  22  with ears  24  having holes  27  to accept a corresponding U-bolt  17 .  FIG. 7  shows the braces  21  in place. The ears  24  are placed on the upright piece  22  so that half of the thickness of each ear  24  extends beyond the upright piece  22 . The ears  24  prevent the brace  21  from becoming loose, dislodged, or misaligned while the device  10  is being installed. The length of the upright piece  22  is the distance between the insides of the flanges  45 .  FIG. 7  shows the upright piece  22  supporting the flanges  45  from being deformed by the clamping force of the U-bolts  17 . The ears  24  retain the brace  21  in close proximity to the U-bolt  17  such that compressive force from the U-bolt  17  is transferred through the upright piece  22  as shown in  FIG. 1 . 
         [0016]    The mounting arms  12 ,  14  are mounted to rails  37 ,  39  at a rearward position from hitch  28 . The mounting arms  12 ,  14  overlie the frame  32  of the vehicle  26 . 
         [0017]    The safety device  10  is formed having mounting arms  12 ,  14 , that are parallel to each other and spaced at a proper distance to overlie the frame rails  37 ,  39 . The distance between the frame rails  37 ,  39  is standard with little variation across vehicles  26  to which the safety device  10  will be mounted. The catch  16  is spaced rearwardly from the mounting arms  12 ,  14 , and roughly equidistant between the mounting arms  12 ,  14 . Catch  16  extends between funneling portions  19 ,  23  and has an inside edge  25 ,  FIGS. 2 and 3 , forming a “U” portion of the trough. Second mounting arm  14  is a mirror-image of first mounting arm  12 . Both of the funneling portions  19 ,  23  are connected to their respective mounting arms  12 ,  14 . When installed, the inside edge  25  is inside the frame rails  37 ,  39 . 
         [0018]    Safety Device  10  is formed having a top surface  88  and a bottom surface  90 , which are separated by an edge  92  which circumscribes the entire safety device  10 . Edge  92  includes an inner edge portion  94 ,  FIG. 2  that extends from first mounting portion  12  to the second mounting portion  14 . Safety device  10  includes a nose  48 . Nose  48  is angled downwardly relative to the balance of the safety device with line  98  defining a crease about which safety device  10  is angled. The portion of top surface  88  on nose  48  defines a ramped surface  52  to safety device  10 . Ramped surface  52  is preferably angled at an obtuse angle a, as seen in  FIG. 4 , relative to the balance of safety device  10 . 
         [0019]    One application of safety device  10  is for use with a fifth wheel hitch  28 . Fifth wheel hitches generally are used to connect a trailer  43  to a vehicle  26 . In the typical configuration, trailer  43  will have a down-turned kingpin  54 ,  FIG. 1A  extending from a forward portion of trailer  43 . Generally, kingpin  54  extends downwardly from a hitch plate  110  which is a metal plate robustly mounted to the underside of the front portion of trailer  43 , and is for providing support, structure, and stability to the kingpin and the trailer. Fifth wheel hitch  28  includes a kingpin slot  56  for accepting kingpin  54  and a locking jaw within kingpin slot  56  which is adapted for gripping and retaining kingpin  54  in kingpin slot  56 . Locking jaw is articulable between a locked and an unlocked position. The locking jaw is well known in the art and may come in various forms such as a single jaw or a double jaw. All serving the same purpose of locking the kingpin  54  in a pivotal connection with the hitch  28 . 
         [0020]    Catch  16  faces the kingpin slot  56  such that if the jaw fails, and as a result kingpin  54  is ejected from fifth wheel hitch  28 , the kingpin will move rearwardly toward safety device  10  and contact the inside surface  25  at catch  16 . Due to the geometry of hitch  28 , and the weight of trailer  43 , the typical direction of ejection of kingpin  54  from hitch  28  is in the direction of safety device  10 . Additionally, the most likely time for the jaw to fail is when the truck is accelerating forward, as the bulk of the weight of the load in trailer  43  will be pushing rearwardly against the jaw in response to the forward acceleration. During such forward acceleration, if the jaw fails, trailer  43  will begin to decelerate relative to vehicle  26 , which will cause kingpin  54  to move rearwardly relative to hitch  28 . Such rearward movement of kingpin  54  will move the kingpin into the safety device  10 . As the kingpin  54  moves rearward, the funneling portions  19 ,  23  will funnel the kingpin  54  into the centrally located catch  16 . Catch  16  will retain trailer  43  in contact with vehicle  26  so that trailer  43  does not come loose from the vehicle, and will provide the operator the opportunity to safely stop the vehicle and attend to repairing hitch  28 . Due to the central location of the catch  16 , the vehicle  26  will be temporarily able to tow the trailer  43  in a similar fashion as would be done with the kingpin  54  properly located in the hitch  28 . Safety device  10  and catch  16  are a significant improvement over the prior art. The standard vehicle  26  which pulls a trailer  43  using a fifth wheel hitch  28  does not include any safety mechanism to retain the trailer in contact with the vehicle in the event the kingpin is loosed from the articulating jaw of the fifth-wheel hitch while the vehicle is in motion. 
         [0021]    Ramped surface  52  functions to protect the leading surface of safety device  10  from blunt trauma from hitting kingpin  54  when trailer  43  is being coupled to fifth wheel hitch  28 . By having a downwardly and rearwardly angled leading surface, kingpin  54  will be pushed up and over ramped surface  52  when trailer  43  is being coupled to vehicle  26 . Ramped surface  52  protects both kingpin  54  and safety device  10  from damage during the coupling of trailer  26  to fifth wheel hitch  28 . 
         [0022]    Safety device  10  has a thickness  100  defined as the distance between the top side  88  and bottom side  90 , as shown in  FIG. 4 . Kingpin  54  is well known in the art, and is typically formed as a rod axially extending from the underside of trailer  43 , with the kingpin  54  having a narrowed section  102  defined by a wider lower section  104  and upper section  106 , where narrowed section  102  has a smaller diameter than both lower section  104  and upper section  106 . Narrowed section  102  has a height  108  defined as the distance between lower section  104  and upper section  106 , as seen in  FIG. 1A . In the preferred embodiment, thickness  100  of safety device  10  is less than height  108 . This is so that when kingpin  54  contacts safety device  10  inner edge portion  94  it is bracketed by lower section  104  and upper section  106  such that trailer  43  is inhibited from upward or lower motion relative to safety device  10 . This is particularly important at catch  16 , which is thinner than height  108  even if funneling portions  19 ,  23  are formed of thicker material. In the case where hitch plate  110  rests on safety device  10 , if an upward force lifts trailer  43 , lower section  104  will catch on inner edge  94  as the trailer moves rearwardly, thereby trailer  43  is restricted from coming out of contact with safety device  10 . In the preferred embodiment, thickness  100  of safety device  10  is less than thickness  108  of king pin  54 .  FIG. 5  shows the trailer  43  in its proper towing position being coupled to the fifth wheel hitch  28 .  FIG. 6  shows the safety device  10  working in the case where the kingpin  54  is dislodged from the hitch  28 . The distance the catch  16  is positioned behind the hitch plate  110  allows room for the kingpin  54  to fall into the safety device  10 . This means the kingpin  54  is caught in the catch  16  when the trailer  43  falls off of the hitch  28  as shown in  FIG. 6 . 
         [0023]    It is understood that while certain aspects of the disclosed subject matter have been shown and described, the disclosed subject matter is not limited thereto and encompasses various other embodiments and aspects. No specific limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. Modifications may be made to the disclosed subject matter as set forth in the following claims.