Abstract:
An easy to use trailer anti-theft device that forms an integral part of said trailer comprising a front exterior wall mounted locking mechanism having a rotatable lock bar extending therefrom with the lock bar having an upper arm pivotally and swivelably connected to a lower swing bar that can be unlocked and moved from a stored position to a downwardly depending blocking position. The lock bar has a partially rotative lower swing arm that under force extends under the trailer substantially in the direction of the trailer king pin.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to locks and, more specifically, to a trailer mountable bar lock to prevent a tractor&#39;s fifth wheel from engaging the trailer&#39;s king pin. 
     The trailer mountable bar lock is preferably mounted to the trailer&#39;s exterior front wall so that the lock bar is peripherally within the confines of the front wall and when unlocked extends vertically beneath the trailer with the pivot point of the swing arm positioned at approximately the base of the trailer so that when pivoted the swing arm will engage the bottom of the trailer. 
     Also provided is a swivel joint allowing for limited rotation of the swing arm to compensate for angular swing arm movement when a tractor attempts to hookup from an angle. 
     2. Description of the Prior Art 
     There are other antitheft devices designed for trailers having king pins. While these devices may be suitable for the purposes for which they where designed, they would not be as suitable for the purposes of the present invention as heretofore described. 
     It is thus desirable to provide a locking mechanism for unattached trailers to prevent unauthorized tractor hookup to said trailers by mounting a king pin blocking member comprising a rotatable locking housing having a lock bar extending therefrom. 
     It is further desirable to provide a swing arm rotative sleeve allowing limited rotative movement of the swing arm to prevent angular attempts to hookup to the trailer. 
     SUMMARY OF THE PRESENT INVENTION 
     A primary object of the present invention is to provide a trailer antitheft device that is permanently attached to a trailer. 
     Another object of the present invention is to provide a trailer antitheft device having housing incorporating a locking mechanism with a lock bar extending therefrom. 
     Yet another object of the present invention is to provide a trailer antitheft device wherein said lock bar rotates between a substantially unblocking horizontal position to a downwardly extending blocking position. 
     Still yet another object of the present invention is to provide a trailer antitheft device wherein said lock bar has a top portion, and a bottom portion. 
     Another object of the present invention is to provide a trailer antitheft device wherein the top portion is fixedly attached to the lock mechanism at one distal end with the bottom portion mounted to the other distal end. 
     A further object of the present invention is to provide a trailer antitheft device wherein said bottom portion comprises a collar portion and a pivotally attached longitudinal portion extending therefrom. 
     A yet further object of the present invention is to provide a trailer antitheft device wherein said bottom collar portion provides for partial rotation of said bottom portion. 
     A still yet further object of the present invention is to provide a trailer antitheft device wherein said pivotally attached longitudinal member pivotally extends under the trailer when a force is applied thereto. 
     Another object of the present invention is to provide a trailer antitheft device that when moved to a blocking position prevents access to the trailer&#39;s king pin by a tractors fifth wheel by keeping the fifth wheel spaced away from the king pin by virtue of the pivotal longitudinal member. 
     Yet another object of the present invention is to provide a trailer antitheft device that is simple to manufacture. 
     Still yet another object of the present invention is to provide a trailer antitheft device that is simple to use. 
     An additional object of the present invention is to provide a trailer locking mechanism that doesn&#39;t require crawling under the trailer to attach a fastenable king pin locking member. 
     Additional objects of the present invention will appear as the description proceeds. 
     The present invention overcomes the shortcomings of the prior art by providing an easy to use trailer antitheft device that forms an integral part of said trailer comprising a front exterior wall mounted locking mechanism having a rotatable lock bar extending therefrom with the lock bar having an upper arm pivotally and swivelably connected to a lower swing bar that can be unlocked and moved from a stored position to a downwardly depending blocking position. The lock bar has a partially rotative lower swing arm that under force extends under the trailer substantially in the direction of the trailer king pin. 
     The rotative collar provides for partial rotation of the longitudinal blocking member when an attempt is made to hook up a tractor to said trailer from an angle. 
     The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which forms a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views. 
     The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       In order that the invention may be more fully understood, it will now be described, by way of example, with reference to the accompanying drawing in which: 
         FIG. 1  is an illustrative view of the trailer bar lock of the present invention in use. 
         FIG. 2  is a side and detail view of the present invention. 
         FIG. 3  is a side and detail view of the present invention in a lock down position. 
         FIG. 4  is a side sectional view of the present invention in a lock down position. 
         FIG. 5  is a frontal view of the present invention in a lock down position. 
         FIG. 6  is a side view of the present invention in a lock down position. 
         FIG. 7  is a perspective view of the present invention. 
         FIG. 8  is an enlarged view of the lock bar of the present invention. 
         FIG. 9  is a perspective view of an additional element of the present invention. 
         FIG. 10  is an enlarged view of the swiveling pivot joint of the bar lock of the present invention. 
         FIG. 11  is an enlarged view of the swiveling pivot joint of the bar lock of the present invention. 
         FIG. 12  is an exploded view of the present invention. 
     
    
    
     DESCRIPTION OF THE REFERENCED NUMERALS 
     Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, the figures illustrate the Trailer Lock Bar Anti-theft Device of the present invention. With regard to the reference numerals used, the following numbering is used throughout the various drawing figures.
           10  Trailer Lock Bar Anti-theft Device of the present invention     12  trailer     14  tractor     16  fifth wheel of  14       18  king pin     20  housing     22  key lock     24  lock bar     26  upper arm of  24       28  swing arm of  24       30  pivot joint     32  swivel joint     34  bolts     36  pivot point of  24       38  first end of  26       40  second end of  26       42  terminus end of  28       44  collar of  32       46  slot of  44       48  stop element of  32       50  rotative shaft of  32       52  first end of  28       54  audible alarm     56  pivot joint apertures     58  pivot joint pin       

     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following discussion describes in detail one embodiment of the invention (and several variations of that embodiment). This discussion should not be construed, however, as limiting the invention to those particular embodiments; practitioners skilled in the art will recognize numerous other embodiments as well. For definition of the complete scope of the invention, the reader is directed to appended claims. 
       FIG. 1  is an illustrative view of the trailer bar lock  10  of the present invention in use. The present invention is an antitheft device for an unattached trailers  12  that prevents a tractor  14  from hooking its fifth wheel  16  to the trailer&#39;s king pin  18 , making the trailer  12  impossible to haul away. 
       FIG. 2  is a side and detail view of the present invention in the raised unblocked position. The present invention is a trailer bar anti theft device  10  comprising a housing  20  with a key lock  22  for a rotatable lock bar  24  with an upper arm  26  and a swing arm  28  connected by a pivot joint  30  extending therefrom movable between a blocking position and an unblocking position. The bar, deployable to a king pin  18  blocking position, incorporates a pivotal segment to prevent damage to the blocking member under a determined force while preventing coupling with a tractor. Optionally, the anti theft device further incorporates means for engaging an alarm when said pivotal segment pivots. 
       FIG. 3  is a side and detail view of the present invention in a lock down position. The present invention is a trailer bar anti theft device  10  comprising a housing  20  with a key lock  22  having a rotatable lock bar  24  with an upper arm  26  and a swing arm  28  connected by a pivot joint  30  extending therefrom movable between a blocking position and an unblocking position. Shown is the present invention lowered into a lock down position effectively blocking the hitching of a trailers fifth wheel to the king pin  18  by creating an un-closable gap with the swing arm. 
       FIG. 4  is a side sectional view of the present invention in a lock bar down position. Shown is a sectional view of the trailer bar lock anti theft device  10  for a trailer  12  comprising a housing  20  bolted  34  to the trailer  12  wall having a key lock  22  with a pivot point  36  for a rotatable lock bar  24  comprising an upper arm  26  and swing arm  28  connected by a pivot joint  30  and a swivel joint  32  movable between a trailer coupling blocking position and an unblocking position. The bar, deployable to a king pin  18  blocking position, incorporates a pivotal segment that under an applied force moves under the trailer preventing coupling with the tractor. 
       FIG. 5  is a frontal view of the present invention in a lock down position. Shown is a sectional view of the trailer bar lock anti theft device  10  for a trailer  12  comprising a housing  20  with a rotatable lock bar  24  comprising an upper arm  26  with a first end  38  and a second end  40  and a swing arm  28  having a first end  52  connected by a pivot joint  30  and a swivel joint  32  with said swing arm  28  having a terminus end  42  movable between a trailer coupling blocking position and an unblocking position relative to the king pin. 
       FIG. 6  is a side view of the present invention in a lock down and block positions. Shown is a side view of the trailer bar lock anti theft device  10  having a pivot joint  30  that serves to give way in the event of a trailer trying to attach its fifth wheel to a trailer&#39;s king pin. Also shown is a swivel joint  32  providing limited swing arm  28  rotation to prevent damage to the bar by a trailer attempting to circumvent the lock bar  24  by angularly coupling to the trailer&#39;s king pin. 
       FIG. 7  is a perspective view of the present invention. Shown is a perspective view of the trailer bar lock anti theft device  10  depicting the range of motion utilized by the device comprising rotating the lock bar  24  from a substantially horizontal locked position to a vertical locked position. A pivotal swing arm  28  is movable along a pivot joint  30  from a vertical position to a trailer king pin blocking position and a rotative swivel joint  32  for partially rotating the swing arm  28  to prevent angularly hitching a tractor to the trailer. 
       FIG. 8  is an enlarged view of the lock bar  24  of the present invention. Shown is an enlarged view of the rotative pivot joint  30  for extending under a trailer and a swivel joint  32  comprises a stationary collar  44  with a slot  46  extending partially therethrough and a rotative shaft  50  with a stop  48  projecting therefrom through said slot  46  for allowing the limited movement of the swing arm  28  moving in an angular direction to prevent damage to the lock bar  24  while backing up at an angle. 
       FIG. 9  is a perspective view of an additional element of the present invention. The trailer bar lock anti theft device  10  further incorporates means for engaging an audible alarm  54  integral with said housing  20  when said pivotal segment pivots. 
       FIG. 10  is an enlarged view of the swiveling joint  32  and pivoting joint  30  connecting the upper arm  26  and the swing arm  28 . Shown is the collar  44  and slot  46  with the stop element  48  projecting from the interior rotative shaft  50 . 
       FIG. 11  is an enlarged view of the pivot joint  30  of the bar lock  24  of the present invention. Shown is an enlarged sectional view of the swing arm  28  depicting the structure of a pivoting joint  30  and a swivel joint  32  in its construction. Additionally shown is the swing arm  28  bending and giving way at its pivot direction upon the application of force. 
       FIG. 12  is an exploded view of the present invention. Shown is a detailed view of the components comprising the lock bar  24  having a pivot joint  30  with a pin  58  and corresponding apertures  56  and swivel joint  32  in communication with the swing arm  28  and the swivel joint  32 . Also depicted is the relationship between the slotted  46  collar  44  affiliated with the upper arm  26  and the shaft  50  and stop  48  which allows for limited rotation of the swing arm  28 . 
     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claims, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.