Abstract:
A safety device ( 20 ) for maintaining in place a pin ( 30 ) retaining a double hand attach ( 22 ) of a trailer hitch to a tractor or truck tow bar ( 24 ). The device prevents the release of the pin during the transport of the trailer by having a superior plate ( 34 ) above the pin limiting the vertical movement of the pin avoiding the popping out. The attaching and the detaching of the device is done because the superior plate may pivot when the pin is released and is maintained in place by a latch ( 36 ) that has a counterweight ( 38 ). The latch is then rocked and kept closed with the action of gravity. The device comprises also fitting screws ( 52, 74 ) allowing to adapt the safety device to several sizes and thicknesses of the different tow bars used on tractors and trucks nowadays so that the device fits any trailer of a farmer yard.

Description:
CROSS-REFERENCE 
   “Not Applicable” 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
   “Not Applicable” 
   NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT “Not Applicable” 
   REFERENCE TO A “SEQUENCE LISTING” 
   “Not Applicable” 
   BACKGROUND OF THE INVENTION 
   It is a general objective of the invention to provide a safety device meant to prevent the accidental release of trailers towed by vehicles particularly farm tractors, a device installed on a straight part of a trailer tow bar. This device having a plate set precisely above a pinhead to avoid the release. The inventor wanted this attach to be adaptable to several tow bars particularly the ones utilized in combination with agricultural tractors and that the installation of the device be done only once on a tractor and that it would suit the majority of the trailers utilized. 
   Furthermore, the inventor wanted that the attach could be adapted easily to different sizes of tractor tow bars. This attach should be simple, affordable and durable and meet the higher standards of safety. Certain tow bars have a Z shape with a short straight part. It is a more limited objective to provide a handle installed on this straight part and comprising a superior plate on which pivots the plate to cover the pin, the handle side comprising rocking means to lock in place the plate when it covers the pin. The trailers utilized have a double hand attach through which passes the pin. 
   More specifically, the objective of this invention is to provide an eccentric locking latch comprising a limiting extension and a rocking part which when rocked causes the limiting extension to retain the plate in place. This latch prevents the releasing from its position of the superior plate during transport of a trailer. 
   A great advantage of the invention is its adaptability of installation to a great deal of tractors, especially that it does not necessitate movements along the tow bar nor vertical movement and that it comprises fitting screws. Furthermore, the way the device is conceived, one can unlock it with one hand only letting the other hand free. The device does not depend on a spring, increasing its durability and its liability, for springs are often quite breakable and not always as resistant. The superior plate can retain a great force. 
   1. Field of the Invention 
   This invention relates to the field of the safety in the attachment of trailers towed by vehicles, especially to secure a pin used to maintain a trailer towed by farm tractors or trucks, preventing the accidental release of the pin and diminishing this potential source of hazards. 
   2. Description of Prior Art 
   Certain types and techniques of construction of safety locks are utilized to secure a pin to retain a tractor or truck tow bar between double hand plates. Generally, what is commonly used nowadays is a safety pin &lt;&lt;Cotter Pin&gt;&gt; located at the base of a maintaining pin, the safety pin passing through a hole drilled in the pin. However, one embodiment utilizes a device  20  placed above a superior hand  26  of a double hand attach  22 , the device comprises a safety plate  34  held by spring means above the maintaining pin  30 . A shortcoming that we observe in the prior art is that there is no simple and independent devices or methods to permit to maintain a pin in place while there is a great force coming from the bottom when it travels in a rugged terrain or when tractors get stuck. The known spring type pin attachments have a great tendency to exit when bottom forces are practiced. 
   The following patents and patent application Publications illustrate such concepts. 
   CA 992791, shows a mechanism installed on a double hand of a trailer, made of a rectangular plate  22  rotating around a pivot to avoid the releasing of a pin during vibrations caused by the transport. 
   The plate is held in place by a spring and has a thickness  24  corresponding to the thickness of a head  20  of its pin. One has to apply a manual force to lift the plate in order to turn it. 
   U.S. Pat. No. 4,783,094, Shows a system installed on a straight bar of a certain type of tractors; a plate avoids the vertical movement of a pin  20 . This system comprises a locking rod sustained by a spring. This rod restrains the movement of the system on the tow bar by penetrating a hole located in the tow bar. Because the holes are not always at the same distance one has to drill new holes at times. One has also to lift the rod to slide the system backward on a tow bar that fits. 
   U.S. Pat. No. 6,193,260: a device installed on a double hand of a trailer adapted to a maintaining pin meant to prevent the accidental loss of the pin and the trailer. 
   FR 2458410: a case including a lock held by a chain. 
   BRIEF SUMMARY OF THE INVENTION 
   It is a safety device for attachment to a vehicle, for example a farm tractor, provided with a tow bar generally rectangular. This tow bar must be attached to a trailer comprising in the front a pair of hands. Regularly, it is a pair of plate that exceed at the front. The hands that are attached to a tow bar are secured by a vertical retention component  30 , which generally takes the shape of a vertical pin for a safety device meant for joining a trailer to a vehicle. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The drawings illustrate an embodiment of the invention. 
       FIG. 1  is a perspective, seen from the front, in a locked position. 
       FIG. 2  is a perspective of the device of  FIG. 1  seen from the back. 
       FIG. 3  is a side view, locked position. 
       FIG. 4  is a top view, locked position. 
       FIG. 5  is a top view, changing position. 
       FIG. 6  is a side view, changing position. 
       FIG. 7  is a side view, open position. 
       FIG. 8  is a top view, open position. 
       FIG. 9  is a perspective view of the device showing a superior assembly. 
       FIG. 10A  is a side view for truck use. 
       FIG. 10B  if a view of  FIG. 10A  with a ball included; 
       FIG. 10C  is a view of  FIG. 10A  with double hand and pin. 
       FIG. 11  is a top view, opened, with double lock 
       FIG. 12  is a top view, closed, with double lock 
       FIG. 13  is a bottom view, opened, with double lock. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the following descriptions the bold numbers refer to items illustrated in the drawings. By definition the front of a device is when looking at a tow bar at the back of a tractor. 
     FIG. 1  shows a safety device  20  on a tow bar  24  of a tractor. One sees a double hand  22  of a trailer comprising a superior hand  26 , a junction piece  27  and an inferior hand  28 . The hands have an aperture  29  that receives a pin  30  that has a handle  32 . The pin passes as well through a straight end  33  of the tow bar. The tow bar has also an aperture, not seen on this figure and the pin crosses the three apertures. A superior plate  34  is located just above the handle to avoid the release of the pin vertically from its position. A latch  36  is maintained against a front maintaining plate  40  by the effect of a counterweight  38 , holding the superior plate in place in an anti-clockwise rotation. The superior plate is also retained in a clockwise rotation by a rear stopping plate  42 . A superior bolt  44  coupled to a superior ring  48  permits the pivoting of the superior plate. The body of the device comprises a socket  50  having a vertical face  51  against which is mounted a latch  36  and where fitting screws  52  appear. It is constituted of two sections: a locking superior section  55  and a tightening inferior section  56  of the straight end of the tow bar. The socket has also a horizontal face  57  on which can pivot the superior plate  34 . The latch  36  revolves around a horizontal pivot which is perceive as a horizontal pivot head  58 . One sees also an inferior passage  59 , the straight end of the tow bar  24  passes in a tightening chamber  56 . The tractor tow bar  24  is inserted in the inferior passage and is maintained in position by the fitting screws  52 . 
   In the shown position, the latch restrains the rotation of the plate and confines it to its locked position. The latch must be pivoted on the axis of the horizontal pivot to an angle of ninety degrees (90 degree.) and be placed in its open position before the plate could be turned to a ninety degree angle (90 degree.) to be in its open position as well. The dimensions of the conception permit to proceed to the opening operation with only one hand.  FIG. 2  shows the device of  FIG. 1  seen from the back, the bottom and the right. One sees the two hands  28 ,  26  of the attach of the double hand trailer and the inferior part of the maintaining pin  30 . One remarks a horizontal pivot  60  ended by a pivot nut  62 . One sees a receiving place  64  meant to receive the pin  30  when it is not utilized. One remarks also a side surface  66  meant to receive the tow bar  24  often provided with a curve in Z  67 . A extension plate  68  comes to receive the receiving place  64 . This view permits to demonstrate the two passages of the principal body, the socket  50 ; the inferior passage  59 , and the superior passage  72 . The tow bar is leaned to the side surface  66  and is maintained in this position by a vertical adjustment screw  74 . One sees clearly the rear stopping plate  42 , and underneath it, one sees the horizontal pivot  60  maintained in places by the pivot nut  62 . One sees also a nut, the vertical nut  78 , which retains the superior bolt. 
     FIG. 3  shows the size view in closed position. The latch is in closed position. One remarks an eccentric  80  in order that the horizontal pivot be placed to the left of the counterweight vertical centre  38 . In this configuration, the horizontal nut head  58  is maintained leaning against the counterweight  38  in order to turn automatically with it. To retain the latch shut more efficiently, a spring can be inserted inside the device. Added to the effect of the counterweight, this spring will provide an additional withholding means and even if this spring is broken, the gravity will keep on activating the latch. 
     FIG. 4  shows a view in a closed position. The plate  34  is also in closed position. On the upper plate is mounted a plate  34  to turn around the superior pivot  49  permitting to turn the plate only in the anti-clockwise direction. On the side plate, towards the top, near the cover plate there is an excess  82  coming from the latch  36 . 
     FIG. 5  shows a top view of the latch turned around the horizontal pivot in its open position, the counterweight  38  is maintained elevated against the action of gravity. The plate  34  is then free to move onto the top of the latch. 
     FIG. 6  shows in side view the  FIG. 5 . One sees how the latch is pivoted around the horizontal pivot  58 . 
     FIG. 7  shows in side view the latch in open position wherein the plate  34  is also pivoted in open position. 
     FIG. 8  shows in bottom view the superior plate  34  pivoted in its open position. 
     FIG. 9  shows a perspective of the safety device completely open: the pin  30  is inserted in its receving place  68 . Of course, a chain can be fixed to this pin in order to maintain it attached to the body of the safety device. On this figure, one sees clearly the aperture  29  in the superior hand. The assembly of the superior vertical pivot is shown in detail. It consists of a vertical bolt  44 , leaning on a ring  48  that is supported on a spacing collar  46 . The collar is of a height slightly more elevated than the thickness of the superior plate in order to permit the entrance of a nut, not shown, to tighten efficiently the assembly and so that the plate could keep on turning. One seeks to tighten firmly this nut so it will not get loose in the long run, absorbing the vibrations and the wear resulting from coming along with frequent and intensive utilization. 
     FIG. 10A  shows another embodiment of the invention: the utilization for a truck. In this case, the receiving case  88  of a truck receives an attachment bar  86  that takes part in the device. 
     FIG. 10B  shows the device of  FIG. 10A  wherein a hitch ball  94  of truck to is be installed. One sees as well how the attach of the trailer  84  covets the hitch ball. Generally, this type of truck attach is provided with a handle  90  activating a support point  92 . 
     FIG. 10C  shows the device of  FIG. 10A  wherein there is no hitch ball although the truck can pull a double handed attach trailer, as tractor trailers. 
     FIG. 11  illustrates a safe lock to tie to a tractor  20 . One sees a latch  36  which is pivoted into a cavity  100  of a superior plate  34 . The superior plate is shown in an &lt;&lt;opened&gt;&gt; position, that is a position in which one may remove a maintaining pin (not shown) which must retain a tractor arm to a double arm of a trailer. One may see an extension  96 , which is added at the back of the main plate  34 . 
     FIG. 12  shows the barrier in operating position wherein the plate  34  is held in place by the latch  36  which is now in a completely vertical position. It is maintained so thanks to the action of gravity caused by the counterweight  38 . In use, this position corresponds to that of a pin  30  underneath the plate  34 . The extension  96  offers the possibility of locking by means of lock hole  98  coinciding with another hole, not seen, in bend  104 , which permits the insertion of a lock or a &lt;&lt;pin&gt;&gt;. 
   The pin  30  is illustrated in  FIG. 12  in a storage  64 . Generally, once the pin is positioned in the receiving place  64 , one pivots the plate  34  into the &lt;&lt;open&gt;&gt; position. In the closed position the pin is prevented from exiting while the tractor is in motion.  FIG. 13  is seen from underneath in position &lt;&lt;opened &gt;&gt;. One sees the safety plaque  104  as well as the safety hole  106 . One sees the latch pivoting about an axis represented by a horizontal pivot head  58 . A stopper plate  40  permits limiting the pivoting of the latch more than 90 degrees. The dimensions of the structure permit operating the openings from a single hand. 
   Ramifications 
   In use, the attach is tremendously reliable and easy to operate. The installation is done directly on the tractor; incidentally, there is no need to drill holes neither in the tow bar nor in the double hand. 
   The device comprises:
         a principal body  50  that can be a simple or a double sleeve comprising a superior face  57  and a lateral face  51 ,   a means to install to the tow bar, that can be centering screws, an eccentric that would be safe and secure,   a superior plate  34  disposed on the superior face that could pivot around an axis  44  and comprising means to retain vertically in place the retention component  30  acting in the maintaining in place of the trailer behind the vehicle.   a pendular latch  36  disposed on the lateral face side, pivoting around an axis  58  and comprising a counterweight  38  retained towards the bottom under the action of gravity and comprising an elongated side  82  with an excess  83  preventing the plate from turning while the elongated side is positioned towards the top.       

   The device comprises also a stopping plate bar  42  preventing the turning of the plate when passed at an open position restraining the rotation of the plate to a 90-degree angle. 
   The device comprises also a latch stopping bar  40  restraining the rotation of the latch to a 90.degree angle. 
   The means to install to a vehicle tow bar comprise fitting screws  52 ,  74 , to the horizontal and to the vertical, permitting to adapt to different sizes of rectangular tow bars. 
   The device installed on a tractor tow bar and the retention component consists in a pin  30 . 
   The device installed on a hitch ball of a truck and the retention components consist in a metal part recovering the hitch ball of the truck. In this particular case, the hand will be modified to adapt to the level difference: in an L section the horizontal part becomes the tow bar. The horizontal plate  34  is fixed on an extension of the trailer hitch. 
   The device comprises as well a pin seat  64  wherein the pin can be tightened in between uses. The device comprises also a chain related to the pin of the device. 
   It is accepted that the realization mode of the present invention that was described above, in reference to the drawings annexed, was given as indicative but certainly not limitative, and that modifications and adaptations could be brought without moving aside the object of the frame of the present invention. 
   
     
       
             
           
             
             
           
         
             
                 
             
             
               LEGEND 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               20 
               Safety device 
             
             
               22 
               Double hand attach 
             
             
               24 
               Tow bar 
             
             
               26 
               Superior hand 
             
             
               27 
               Junction piece 
             
             
               28 
               Inferior hand 
             
             
               29 
               Aperture 
             
             
               30 
               Maintaining pin 
             
             
               31 
               Retaining pin 
             
             
               32 
               Pin handle 
             
             
               33 
               Straight end 
             
             
               34 
               Safety_plate 
             
             
               36 
               Pendular latch 
             
             
               38 
               Counterweight 
             
             
               40 
               Front stopping plate 
             
             
               42 
               Rear stopping plate 
             
             
               44 
               Superior axis 
             
             
               46 
               Spacing collar 
             
             
               48 
               Superior ring 
             
             
               49 
               Radius 
             
             
               50 
               Principal body 
             
             
               51 
               Lateral face 
             
             
               52 
               Horizontal fitting screws 
             
             
               55 
               Locking place 
             
             
               56 
               Tightening chamber 
             
             
               57 
               Superior face 
             
             
               58 
               Horizontal pivot head 
             
             
               59 
               Inferior passage 
             
             
               60 
               Horizontal pivot 
             
             
               62 
               Pivot Nut 
             
             
               64 
               Receiving place 
             
             
               66 
               Support 
             
             
               67 
               Z turn 
             
             
               68 
               Extension plate 
             
             
               72 
               Superior passage 
             
             
               74 
               Vertical fitting screws 
             
             
               78 
               Vertical Nut 
             
             
               80 
               Eccentric 
             
             
               82 
               Overhang component 
             
             
               83 
               Excess component 
             
             
               84 
               Trailer attach 
             
             
               86 
               Truck bar 
             
             
               88 
               Truck attach 
             
             
               90 
               Handle 
             
             
               92 
               Support point 
             
             
               94 
               Truck ball 
             
             
               96 
               Extension 
             
             
               98 
               Lock hole 
             
             
               100 
               Cavity 
             
             
               102 
               Direction 
             
             
               104 
               Bend 
             
             
               106 
               Cotter pin hang