Abstract:
A protective lock assembly for preventing unauthorized access to a pintle receiving hitch which assembly includes opposing plate members which are mounted on opposite surfaces of the hitch and wherein a tongue carried by one plate member is engageable by a lock whose shackle is protectively seated within a housing which extends from the other plate member.

Description:
BACKGROUND OF THE INVENTION  
   1. Field of the Invention  
   This invention is generally directed to devices for use in preventing unauthorized access to hitches of the type which are used to receive a pintle of a towing vehicle and which are often associated with heavy duty trailer type equipment used in construction and in maintenance. More particularly, the present invention is directed to a protective device which functions to seal off a hitch ring of a trailer device so that it can not be towed by unauthorized personnel and wherein the device is locked to the hitch ring in such a manner that unauthorized tampering of the lock, shackle or bolt is prevented.  
   2. Description of the Related Art  
   Equipment used in the construction and maintenance industry is frequently mounted on a trailer to promote portability. Many such heavy duty type trailers utilizing a  hitch which is adapted to be mounted to a tongue of a towing vehicle by way of a pintle which extends through an opening in a circular ring or hook type device defined by the hitch.  
   It is often not possible to leave or store such trailers or trailer mounted equipment in secured areas. Often, it is necessary that such equipment and trailers be left on site and, unfortunately, such equipment and trailers are subject to misappropriation or theft.  
   In an effort to deter the unauthorized use or theft of such trailers and equipment, there have been a number of innovations directed to devices for securing such trailers and equipment by preventing the use of the hitch assemblies associated therewith. By way of example, heavy duty chains are often passed through a hitch rings and locked upon themselves in order to obstruct the opening through the hitch rings. Unfortunately, such chains and the locks used to secure them are subject to tampering using bolt cutters and other devices.  
   Other protective devices include assemblies which are designed to be mounted within a hitch ring and secured utilizing conventional locks. However, in many such assemblies, the lock bolt or lock shackle may be easily  accessed so that the shackle or bolt can be tampered with utilizing bolt cutters or other tools.  
   Some examples of prior art type protective devices for pintle hitch assemblies are disclosed in U.S. Pat. No. 4,186,575 to Bulle; U.S. Pat. No. 5,343,720 to Slater; U.S. Pat. No. 4,480,450 to Brown; U.S. Pat. No. 5,332,251 to Farquhar; and U.S. Pat. No. 4,380,160 to Hoffman.  
   In view of the foregoing, there remains a need to provide for a protective device which may be secured to a hitch adapted for use with the pintle of a towing vehicle wherein the assembly provides a secure housing for a lock such that the lock can not be tampered with utilizing bolt cutters and other tools which could be used to otherwise circumvent the protective device.  
   SUMMARY OF THE INVENTION  
   The present invention is directed to a protective lock assembly for preventing unauthorized access to a pintle receiving hitch associated with a trailer type vehicle or trailer mounted equipment wherein the assembly includes a pair of opposing plates of a size to engage over the upper and lower surfaces of the hitch when in use to thereby block access to the opening in the hitch. One of the plates of the assembly includes a projecting tongue of a length to extend  through the hitch and through an opening in the other plate. The other plate includes a housing which extends remotely from the hitch and which surrounds an end portion of the tongue when the two plates are placed into opposing relationship on the upper and lower surfaces of the hitch.  
   The housing is of a sufficient length such that when the two plates are mounted to the hitch that the tongue of the one plate remains encircled by the housing. The tongue further includes structure for cooperatively receiving a shackle or bolt of a conventional lock which is inserted within the housing and thereafter closed into engagement with the tongue to thereby prevent the separation of the two plates relative to the hitch. Further, the structure of the housing fully surrounds and thereby conceals the shackle or lock bolt associated with the conventional lock thus preventing access thereto when the plates are locked into assembled relationship.  
   In a preferred embodiment of the invention, the shackle or bolt of the conventional lock is received in at least one opening provided in an end portion of the tongue.  
   In accordance with a further embodiment of the invention, to facilitate handling of the protective device of  the present invention, the two plate components are preferably flexibly jointed such as by a length of chain or cable to thereby prevent the accidental displacement of the two components but also permitting the components to be maneuvered so as to be brought into a locked relationship with a hitch as described above.  
   It is the primary object of the present invention to provide a protective device for use with pintle type hitches wherein the device seats within a hitch ring and can not be removed therefrom due to the engagement of a shackle of a lock with a component of the device and which component is encircled in a protective manner within the device so that tampering with the lock shackle or lock bar is not possible.  
   It is yet a further object of the present invention to provide a very secure, sturdy and low cost protective device for deterring theft of trailers and trailer mounted equipment wherein the device can be secured to the hitch of the trailer or trailer mounted equipment in such a manner that a lock used to secure the device in place can not be tampered with utilizing bolt cutters or other tools.  

   
     BRIEF DESCRIPTION OF THE DRAWINGS   
     A better understanding of the invention will be had with respect to the accompanying drawings wherein:  
       FIG. 1  is a perspective illustrational view showing the protective lock assembly of the present invention mounted within a hitch ring extending from a tongue of a trailer;  
       FIG. 2  is a front elevational view of the protective lock assembly as shown in  FIG. 1 ;  
       FIG. 3  is a cross-sectional view taken along line  3 — 3  of  FIG. 1 ;  
       FIG. 4  is a cross-sectional view taken along line  4 — 4  of  FIG. 2 ;  
       FIG. 5  is a cross-sectional view taken along line  5 — 5  of  FIG. 2 ;  
       FIG. 6  is a partial cross-sectional view taken along line  6 — 6  of  FIG. 3 ; and  
       FIG. 7  is an assembly view of the protective lock assembly of the present invention showing a specialized lock associated therewith.  
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT  
   With continued reference to the drawing figures, the  protective lock assembly  10  of the present invention is shown in  FIG. 1  as being mounted within a hitch  12  of a trailer (not shown). The hitch is shown as being mounted to the front of the trailer tongue  14  on mounting plates  15 . The hitch is in the form of a ring having an opening  16  therethrough, as shown in  FIG. 3 . The ring is of a size to receive a pintle associated with the hitch assembly of a towing vehicle (not shown).  
   The protective lock assembly  10  includes a first plate  20  of a size to be seated along either the upper or lower surface of the hitch ring as is shown in  FIGS. 1-3 . In the drawing figures, the plate  20  is shown as being seated on the upper surface of the hitch ring, however, the structure of the present invention also permits the plate  20  to engage the lower surface of the ring. Extending from the plate  20  is a post or tongue  22  which extends from the plate at a given distance as will be described in greater detail.  
   Along the outer end portion  23  of the tongue is provided a means for allowing engagement of a shackle  25  or lock bolt of a lock  30 . In the preferred embodiment as shown in the drawing figures, the means for allowing the engagement is at least one opening  28  provided in the outer end portion  of the tongue which opening is of a size to receive the shackle associated with the lock  30 . As opposed to the opening, one or more laterally extending pins could be used to provide surfaces for engaging the shackle.  
   The protective lock assembly  10  further includes a second plate  35  also of a size to cover the upper or lower surface of the hitch ring. Again, although the plate  35  is showing engaging the lower surface of the hitch ring in the drawing figures, the structure of the present invention also permits the plate to engage the upper surface of the hitch ring.  
   Extending from the plate  35  is a housing  36  which is welded or otherwise secured generally concentrically with respect to a center of the plate  35 . The housing extends to a outer open and free end  38 .  
   In the embodiment shown in the drawing figures, the housing is generally cylindrical, however, other configurations may be used provided that the housing  36  defines walls which completely surround the tongue  22  when the tongue is inserted within the housing.  
   In order to permit the tongue  22  to be inserted within the housing  36 , an opening  40  is provided through the plate   35 . The opening  40  need only be large enough to permit the tongue  22  to be inserted therethrough.  
   The tongue  22  is of sufficient length such that when the plate  20  is mounted to either the upper or lower surface of the hitch ring, the end portion of the tongue extends through the opening  40  and into the housing  36 . Further, the opening  28  in the tongue  22  is surrounded by the housing  36 , as is shown in  FIG. 3 , when the lock assembly is in use. Because of the positioning of the opening  28  within the housing, it is necessary that the lock  30  be inserted within the open end portion  38  of the housing  36  until such time as the shackle  25  associated with the lock can be closed through the opening  32 . Once closed, the shackle is completed surrounded by the housing  36  such that no portion thereof can be tampered with utilizing tools such as chisels or bolt cutters. In this manner, unauthorized removal of the protective lock assembly is effectively prevented.  
   In the preferred embodiment of the invention as shown in  FIG. 7 , the lock  30  is a specially designed lock referenced in the industry as the NT: Shrouded Padlock, titanium series, by Master Lock®. This type of lock has the shackle  25  protected by spaced and extended arm portions  31  and  32  of the lock housing  33 . In this manner, the housing  33  of the  lock provides further protection for the shackle by obstructing access into the housing  36  of the protective lock assembly  10 . As shown, a key slot  34  is provided for operating the shackle  25  and the slot is spaced from the housing  36  when the lock  30  is in use.  
   In the preferred embodiment shown, the housing  30  is generally of a diameter which permits the lock housing to be slidingly received therein while minimizing any free space between the housing of the lock and the housing  36  of the protective lock assembly. Again, this close fit between the lock housing and the protective lock assembly housing prevents unauthorized tampering with the lock shackle.  
   It should be noted that in the present description that the term shackle is referenced as being the member of the lock  30  which extends through the opening in the tongue  22  to secure the tongue in place. However, it is possible that the lock could be used with a sliding or deadbolt type mechanism as well and, therefore, such mechanisms should be considered within the meaning of “shackle” for purposes of definition and for purposes of the following claims.  
   In some embodiments, to facilitate the alignment of the shackle  25  of the lock  30  with the at least one opening  28   of the tongue  22 , the opening  28  is provided at a point along the tongue such that when the lock  30  is inserted within the housing  36  with the ends of the arm portions  31  and  32  engaging the plate  35 , the shackle  25  is aligned with the opening. Further, with this association of components, the plates  20  and  25  will be locked in tightly seated contact on opposite surfaces of the hitch ring thus providing additional security.  
   To prevent accidental separation of the plate  20  and the plate  35 , in the preferred embodiment, the two components are tethered to one another such as by utilizing a chain  52  which is welded along the peripheral edge of each of the plates. The length of chain should be sufficient to permit the two plates to be readily maneuvered so that they may be brought into assembled relationship on opposite surfaces of the hitch as is shown in  FIG. 1 . As opposed to the chain shown, secure wires, cables or other components may be used.  
   The components of the protective lock assembly of the present invention preferably formed of steel plate to further deter tampering.  
   The tongue  22  may include two or more spaced openings or other means for allowing engagement with the shackle  25  of  the lock  30 . This could be necessary in allowing the protective lock assembly to be used with hitch rings of differing thickness.  
   In use, to secure the hitch of a trailer or trailer mounted equipment, the plate  20  is positioned either on the upper or lower surface of the hitch ring with the tongue  22  extending through the opening in the ring. Thereafter, the plate  35  is aligned such that the tongue  22  passes through the opening  40  therein and the plate  35  seated on the opposing surface of the ring. With the plates engaging the upper and lower surfaces of the ring, the lock mechanism  30  is inserted within the open end of the housing  36  and the shackle or locking bar associated therewith is activated such as by the use of a conventional key to thereby engage the shackle through the opening  28  in the tongue and thereby prevent disassemble of the plates  20  and  35 .  
   The foregoing description of the preferred embodiment of the invention has been presented to illustrate the principles of the invention and not to limit the invention to the particular embodiment illustrated. It is intended that the scope of the invention be defined by all of the embodiments encompassed within the following claims and their equivalents.