Abstract:
A lock guard is provided for padlocks securing different type J-hook latches of roll up doors in their locking position. The lock guard shrouds the shackle of the padlock thereby deterring vandals use of cutting tools to sever the shackle.

Description:
RELATED APPLICATIONS 
     The priority rights are claimed concerning the inventor&#39;s United States provisional patent application for Roll-Up Door Lock Guard, Ser. No. 60/855,977 filed Nov. 1, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     Many semi-trailers used for merchandise transport have a rear roll-up door. Such doors customarily have rollers and hinged horizontal panels that fold as the door is opened by being slid customarily in an upward direction with the rollers in glides that typically curve inward at the top of the trailer at an angle approximately ninety degrees. Various locking devices have been proposed to secure roll-up doors against thieves who use bolt cutters, power hack saws, and sledge hammers to destruct the latch and/or the padlock securing the latch. The doors are traditionally secured by a J-hook pivotally mounted on the door near its bottom end. Rotation of the J-hook in a clockwise direction engages the claw of the J-hook with a fixed structural component in a rear transverse bumper, a portion of which extends rearward of the door. The operating lever of the J-hook is usually further secured by a padlock with its shackle extending through openings in the operating lever and a pivoted a lever latch a stop block fixed to the door. One J-hook manufacturer provides a lever stop having an opening through which the shackle also extends when the lock secures the J-hook lever. There are basically two styles of J-hooks for securing roll-up doors in the industry, which are named after the principal manufacturers. Most other manufacturers use a design of one of the primary two. Prior art regarding lock guards is replete with a myriad of diverse and specialized lock guards. Particularly relating to roll-up doors are Eberly U.S. Pat. No. 4,895,077 and Sole et al. U.S. Pat. No. 5,737,946. Whereas both Eberly and Sole teach the use of lock guards to protect padlocks securing the locking mechanism on roll-up doors, both applications are designed to function on only one of the two primary locking handle manufacturers and their designs will not allow universal applicability. While all of the aforementioned prior art constructions are more than adequate for the basic purpose and function for which they have been specifically designed, none of these patented devises have been specifically designed to transcend the nuances of difference between the two primary manufacturers such that one common lock guard can transcend the difference. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The two most commonly used J-hook roll-up door securing devices have latching levers pivotally secured to the lower part of the door on an axis perpendicular to the door. The hook and the latching lever are rigidly secured to one another and the free end of the latching lever has a downwardly extending distal flange with an opening or bore whose axis extends parallel to the rear side of the roll-up door. There are variations in the structure of the components in the currently used J-hook devices used for latching and locking roll up doors and the herein disclosed lock guard accommodates those variations. It also became apparent in development of the invention that the lock guard should provide protection for long shackle padlocks as well as regular padlocks. One longitudinal end of the lock guard is provided with an upwardly open trough or guide chute which not only restricts access to an installed padlock but also helps to position the shackle when installing the padlock in its locking position. The opposite end of the lock guard is provided with a shelter which permits the padlock case to be turned, after the free end of the shackle has been inserted into the locking tabs, to a position aligning the free end of the shackle with its mating opening in the case. The lock guard is stabilized by the non-pivoting or free end of the shackle of the padlock passing through two aligned openings in parallel vertical interior wall members of the guard. The free end of the shackle also passes through an aligned opening in the J-hook operating lever and the operating latch. One of the two most commonly used J-hook securing devices has an opening in its stop block through which the shackle also passes, but the other or second of the most commonly used J-hook securing devices does not have such an opening in its stop block. The lateral position of the stop block of the second J-hook securing device is off set in relation to the lateral position of the stop block of the other J-hook securing device. A notch is formed in the rear wall of the lock guard to accommodate the stop block of the second J-hook securing device. The herein disclosed lock guard is advantageously used in protecting padlocks securing either of the commonly used J-hook securing devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One embodiment of the invention is illustrated in the drawings, in which: 
         FIG. 1  is a partial rear view of a semi-trailer showing the lock guard protecting a padlock securing the J-hook in its locking position; 
         FIG. 2   a  is a top view of the lock guard and padlock positioned for connection with one style of J-hook operating handle and latch; 
         FIG. 2B  is a top view of the lock guard and padlock of  FIG. 2A  secured to the J-hook and its latch; 
         FIG. 3  is a side view of the J-hook components, padlock and lock guard shown in  FIG. 2A  with parts broken away for illustration purposes; 
         FIG. 4  is an end view of the lock guard and padlock shown in  FIG. 2A ; 
         FIG. 5  is an overhead perspective view of the lock guard; 
         FIG. 6  is a rearward perspective of the lock guard; 
         FIG. 7A  is a side view, with parts broken away, showing the lock guard used with a second style J-hook; 
         FIG. 7B  is a side view similar to  FIG. 7A  with additional parts broken away for illustration purposes, and 
         FIG. 8  is a perspective showing the lock guard used with the second style J-hook. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The lock guard illustrated in the accompanying drawings is designed to protect the padlock  11  securing either the operating lever  12  of a J-hook securing device  13 , shown in  FIGS. 1 ,  2 A,  2 B and  3 , or the operating lever  112  of a similar J-hook securing device shown in  FIGS. 7A ,  7 B and  8 . As shown in  FIG. 1  the operating lever  12  of the J-hook securing device  13  is pivotally secured to the roll up door  14  of a semi-trailer  16  on a horizontal pivot axis  17  extending longitudinally in relation to the trailer  16  and at a right angle in relation to the roll up door  14 . A J-hook  18  is rigidly secured to the lever  12  and in its illustrated locking position hooks through holes precut in the top of the bumper  15  at the rear end of the floor of the trailer  16 . The long shackle padlock  11  is protected by a lock guard  19 . Referring also to  FIG. 3 , a lever stop  21  integrally formed on a mounting plate  22  rigidly secured to the roll up door  14 , limits clockwise downward pivotal movement of the lever  12  so that the laterally extending horizontal opening  23  in the downwardly extending locking flange  24  of the lever  12  aligns with horizontal opening  26  in the downward extending flange  27  of the locking latch  28  pivotally connected to the mounting plate  22  by a pivot pin  29  for pivotal movement about a horizontal pivot axis  31  perpendicular to the roll-up door  14 . The upper end of the stop  21  abuts a horizontally extending ledge  32  formed on the distal end of the lever  12 . Referring also to  FIGS. 2A ,  3 ,  5  and  6 , a notch  36  is provided in a rear wall  37  of the lock guard  19  into which the stop  21  extends when the padlock  11  and lock guard  19  are installed as shown in  FIGS. 2B and 3 . The vertical rear wall  37 , extending parallel to the roll up door  14 , also includes a notch  38  extending downward from its upper end a sufficient distance to permit entry of the locking flange  24  of the lever  12  and the locking flange  27  of the locking latch  28 . The rear wall  37  extends the full longitudinal length of the lock guard  19  and when installed is in substantially parallel relation to the roll-up door  14 . A top wall or roof  41  at a first longitudinal end of the lock guard extends horizontally between, and is rigidly secured to, the rear wall  37  and a segment  42  of a vertical front wall  43 . Segment  42  and an in intermediate segment  44  of the front wall  43  are substantially the same height; however, a third segment  46  of the front wall  43  is of a reduced height from a horizontal bottom of the front wall  42 . The rear wall  37  has a reduced height segment  52  at a second longitudinal end of the lock guard. An end wall  53  and a partial bottom wall  54  together with wall segments  46 ,  52 , form a trough  56  adjacent and parallel to the rear wall  37  for guiding the shackle  61  during installation of the padlock  11 . A short transverse wall  45  extending upwardly from the bottom of lock guard about one third its height, rigidly interconnects wall segments  44  and  46 . An increased height portion of the wall segment  46  forms an intermediate wall  83  parallel to the rear wall  37 . The rear wall  37 , the intermediate wall  83  and the trough  56  form a guide channel for guiding the shackle  61  during its installation. The guide channel is open at its bottom except for the short bottom wall  54 . 
     Referring also to  FIGS. 5 and 6 , a first vertical transverse wall or wall member  66  adjacent the first end side of the notch  38  extends downwardly from the horizontal roof  67  slightly less than one half the height of the rear wall  37  to which it is rigidly secured by welding. The first transverse wall or wall member  66  is also welded to the rear wall  37  and to the front wall intermediate segment  44  and has a horizontal annular opening  71  for the lock shackle  61 . A second transverse vertical interior wall  81  is welded to and extends at a right angle from the rear wall  37  to the intermediate wall  83  to which it is also rigidly secured. A horizontal top wall  84  rigidly interconnects the intermediate wall  83 , the second transverse interior wall  81  and the rear wall  37 . The top wall  84  has a cut out or notch  86  extending inwardly from the rear wall  37  for accommodating the lever stop  21  on the locking plate  22 . The second transverse vertical interior wall  81  includes an annular horizontal opening  88  which is horizontally aligned with the opening  71  in the transverse vertical wall  66 . The transverse vertical walls  66 ,  81  are spaced from the bottom of the lock guard at least one half the height of the lock guard, thus providing adequate space for insertion of the shackle into the guide channel  56 . An intermediate horizontal wall  70  and a transverse vertical wall  75  between wall  83  and front wall segment  44  add reinforcement to the lock guard. As shown in  FIG. 2A , the open shackle  61  of the padlock  11  is inserted into the trough  56  in preparation for insertion of the unhinged leg of the shackle  61  into the aligned openings  88 ,  23 ,  26 ,  71  in the transverse wall  81 , the lever flange  24 , the locking latch flange  27  and the transverse wall  66 . 
       FIGS. 2A and 4  show the open shackle  61  being positioned for insertion through the aligned openings  71 ,  88  in the transverse walls  66 ,  81 . After insertion of the unhinged leg of the shackle through the openings  88 ,  23 ,  26 ,  71  a finger may be inserted though an opening defined by the rear wall  37 , wall segment  83 , bottom wall  54  and interior wall  81  to engage and force closure of the shackle  61 . A horizontal reinforcing ledge  91  extending horizontally rearward a short distance from the lower end of the back wall  37  also helps to orient the lock guard and padlock during installation. Upon closure of the installed padlock  11 , the case  96  of the padlock is disposed within the cavity  99  formed by the rear wall  37 , the front wall segment  42 , top wall  41  and transverse interior wall member  66 . As shown in  FIG. 4 , the before mentioned protective cavity  99  is open at its bottom and is at least as wide as the width of the case  96  of the padlock  11 , so as to permit the case  96  to be rotated about its hinged leg to a locking position, as illustrated in  FIG. 3 . The protective cavity or shelter  99  is longer, in the elongated direction of the lock guard, than the length of the padlock case  96 . In its installed condition the bottom of the lock guard is close to the semi-trailer bumper  15 , thus limiting underside access to the padlock  11 . As shown in  FIGS. 3 ,  6 ,  7 A and  7 B, a quadrilateral segment of the rear wall has been removed at the first end of the lock guard leaving a trapezoidal shaped notch or opening  51  in the rear wall  37  adjacent the open end and bottom of the protective shelter or cavity  99  for the case  96  of the padlock  11 . The notch  51  provides additional space for the fingers of the hand installing the padlock  11  including the steps of installing the shackle  61  in the aligned openings in the J-hook apparatus and lock guard and then closing the shackle  61 . 
       FIGS. 7A ,  7 B and  8  show the lock guard used with the padlock  11  securing the pivot or securing lever  112  of a second style J-hook securing device to a locking latch  128  pivotally supported on a mounting plate  122  by a horizontal pivot pin  129 , whose axis is perpendicular to the roll up door  14 . A vertical locking flange  124  on the distal end of the operating lever  112  extends horizontally from the lever  112  toward the mounting plate  122  and the lever  112  is positioned in a valley between the intermediate front wall segment  44  and the intermediate wall segment  83 . A horizontal lip  131  projects horizontally from the end of the lever  112  and from the locking flange  124  and engages a lever stop  121  in the locking position of the J-hook pivot lever  112 , as shown in  FIGS. 7A ,  7 B and  8 . Unlike the J-hook device shown in  FIGS. 2A ,  3  and  4 , the stop flange  121  on the mounting plate  122  includes an annular horizontal opening  132  which in the illustrated locking position of the lever  112  is horizontally aligned with an annular opening  133  in the locking flange  124  of the lever  112 , an annular opening  136  in a flange  137  of the locking latch  128  and the openings  88  and  71  in the transverse walls  81  and  66 , respectively. All three of the flanges  121 ,  124  and  137  fit within the opening or notch  38  and in the space between the top wall  41  and the abbreviated top wall  84 . 
     The herein disclosed lock guard protects shackle padlocks securing either of the two most commonly used J hook levers employed to latch roll up doors in their closed position. The guide trough  56  helps to position the shackle and together with interior and exterior walls provides padlock shelter denying access to bolt cutter and saw devices. The first, second and third front wall segments  42 ,  44  and  46  positioned large, medium and small distances from the straight rear wall  37  contribute to a compact protective guard. Having thereby described the subject matter of the present invention, it should be apparent that many substitutions, modifications and variations of the invention are possible in light of the above teachings. It is therefore to be understood that the invention as taught and described herein is only to be limited to the extent of the breath and scope of the appended claims.