Patent Publication Number: US-7210316-B1

Title: Door lock for trailers and cargo containers

Description:
FIELD OF THE INVENTION 
   This invention relates in general to lock assemblies for locking hinged doors such as on trailers and cargo containers. 
   BACKGROUND OF THE INVENTION 
   Many trailers and cargo containers have hinged doors. One type of door lock assembly comprises a shaft or rod that extends on the exterior of the door past opposite edges of the door. The shaft may be oriented vertically or horizontally, and has ends that engage brackets mounted adjacent to the door. When the shaft is rotated in one direction, it can be disengaged from the brackets to allow the door to be opened. A handle is pivotally mounted to the shaft for causing the rotation. The handle extends past an edge of the door and engages a pair of hasps. One of the hasps is fixed while the other is pivotal. Both hasps have holes that register when aligned. The hasps are contoured to define a closed channel or passage for the handle. Typically, a padlock is inserted through the mating holes of the hasps. 
   Padlocks are relatively easy to break or cut. Once the padlock is broken, the door can be readily opened. Devices have been proposed that purport to be more resistant to tampering than a padlock. Some of the devices include a cover that fits over the hasps. A key-actuated lock member is mounted to the housing and has a lock pin that strokes in response to rotation of the key. The lock pin is configured to extend through mating holes of the hasps. 
   SUMMARY OF THE INVENTION 
   In this invention, the lock assembly has a housing with an open back for placing the housing over the hasp and against the door. A retainer pin extends through an aperture in the housing. The retainer pin is movable relative to the housing along an axis of the pin for passing through a hole in the hasp. The retainer pin has a pair of axially spaced apart shoulders on it. 
   A key actuated lock member is mounted to the housing. The lock member has a lock pin that extends within the housing into engagement with the retainer pin between the shoulders in response to rotation of the lock member. This engagement prevents removal of the retainer pin from the hasp while locked. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a portion of a prior art door lock. 
       FIG. 2  is a perspective view of a lock assembly in accordance with this invention incorporated with the door lock of  FIG. 1 . 
       FIG. 3  is an enlarged sectional view of the lock assembly of  FIG. 2 , taken along the line  3 — 3  of  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , the door lock assembly shown is a type for securing two hinged doors  11 ,  13  of a trailer or cargo container. A rod or shaft  15  extends vertically past the upper and lower edges of door  13 . In some applications, shaft  15  extends horizontally. Shaft  15  has end portions that engage locking brackets or keepers(not shown) mounted to the trailer adjacent door  11  when rotated to the position shown in  FIG. 1 . A handle  17  is pivotally mounted to shaft  15  for rotating shaft  15  from a locked and unlocked position. Handle  17  extends past door  13  over to door  11  while in the locked position and engages a hasp assembly  19 . 
   Hasp assembly  19  typically has a mounting plate  21  that is secured to the door. A lower fastener  23  secures the lower portion of mounting plate  21  to door  11 . A fixed hasp  25  is welded to mounting plate  21 . A pivotal hasp  27  is pivotally mounted to mounting plate  21  by a fastener  29 . Fastener  29  extends through mounting plate  19  and pivotally secures the upper portion of mounting plate  19  to door  11 . Each hasp  25 ,  27  has a hole  31 , the holes  31  aligning with each other while in the position shown in  FIG. 1 . Hasps  25 ,  27  are configured to define a closed channel  32  while in the locked position shown in  FIG. 3 . Closed channel  32  retains handle  17  to prevent movement of handle  17 . Swinging pivotal hasp  27  out of the way allows handle  17  to be lifted from fixed hasp  25 . Rotating handle  17  outward from door  11  releases shaft  15  from the keepers at the lower and upper edges of door  11 . 
   Referring to  FIG. 2 , a lock assembly  33  for locking handle  17  within hasps  25 ,  27  includes a housing  35  that fits over the entire hasp assembly  19 . Housing  35  fits over mounting plate  21  as well as fasteners  23 ,  29  and hasps  25 ,  27 . In this embodiment, housing  35  is generally rectangular, having a greater length than its height. However the length could be less than the height, and housing  35  could be shapes other than rectangular, such as cylindrical. Housing  35  has a front wall  37  that has a substantially flat portion in a plane parallel to the plane containing door  11 . Housing  35  has two sidewalls  39  in this embodiment that extend from opposite side edges of front wall  37  toward door  11 . Housing  35  has two end walls  41 ,  42  that are substantially parallel to each other and perpendicular to sidewalls  39 . As shown in  FIG. 3 , housing  35  has an open back for placement over hasp assembly  19 . Preferably a gasket  43  is bonded to the free edges of end walls  41 ,  42  and sidewalls  39  for preventing marring of the finish of door  11  when in contact. As shown in  FIG. 2 , each sidewall  39  has a rectangular recess  45  on its free edge that is sized to accommodate handle  17 . The distance between end walls  41 ,  42  at the free edges is greater than the length of mounting plate  21 . 
   As shown in  FIGS. 2 and 3 , upper end wall  41  has an enlarged thickness portion or boss  46 . An aperture  47  extends through boss  46 . A bulkhead  49  is formed within the interior of housing  35  in a plane parallel to the plane containing lower end wall  42 . Bulkhead  49  is spaced above lower end wall  42  a selected distance and has an aperture  51  that aligns with aperture  47 . 
   A retainer pin  53  extends through aperture  47 , hasp holes  31  and bulkhead aperture  51 . The lower end of retainer pin  53  is recessed within housing  35  between bulkhead  49  and lower end wall  42  while in the locked position of  FIG. 3 . Retainer pin  53  can be moved upward completely out of registry with apertures  47  and  51 . A loop or bail  55  on the upper end of retainer pin  53  limits the downward travel of retainer pin  53  within housing  35 . Retainer pin  53  is preferably cylindrical and has a reduced diameter section  57  that is also cylindrical but of a smaller diameter. Reduced diameter section  57  defines two opposed shoulders  59  that are in planes perpendicular to the axis of retainer pin  53 . 
   A key actuated lock  61  is mounted to a protruding boss  63  formed in front wall  37 . Lock  61  is of a conventional type that operates with a key and has a pin or bolt  65  that extends and retracts when actuated by the key. Lock pin  65  has a length selected so that its free end will pass into reduced diameter section  57 , although it need not touch reduced diameter section  57 . Lock pin  65  protrudes further inward than shoulders  59  so that if one pulls upward on retainer pin  53  while lock pin  65  is extended, lower shoulder  59  will contact lock pin  65  and prevent the removal of retainer pin  53 . Pushing down on the upper end of retainer pin  53  would cause lock pin  65  to contact the upper shoulder  59 . While some axial movement can occur, the engagement of lock pin  65  with the reduced diameter section  57  limits the movement to a small amount. Lock pin  65  is shorter than retainer pin  53  in this embodiment. 
   In operation, the user closes the door conventionally and rotates shaft  15  to the closed position with handle  17 . The user pivots pivotal hasp  27  upward and drops handle  17  into the receptacle formed by fixed hasp  25 . The user then releases pivotal hasp  27 , which causes the holes  31  to align. The user then pulls retainer pin  53  upward sufficiently so that it will clear hasps  25 ,  27 . Alternately, the user may completely remove retainer pin  53 . The user places housing  35  over hasp assembly  19  as shown in  FIG. 3 . The user then inserts retainer pin  53  through the aligned holes  31  and through hole  51  in bulkhead  49 . The user then uses the key (not shown) to rotate lock  61 , causing lock pin  65  to extend out to the extended position into proximity with reduced diameter portion  57 . The user then removes the key. 
   The invention has significant advantages. The housing fits entirely over the hasp assembly including the mounting plate. Enclosing the entire hasp assembly prevents an intruder from trying to shear off the fasteners of the hasp mounting plate for the hasp. The housing is preferably formed of a strong material, such as cast aluminum, so as to resist breaking due to blows deliver by an intruder. The retainer pin protrudes only a short distance from the upper end does not protrude at all from the opposite end, so as to resist efforts by an intruder to remove the retainer pin. 
   While the invention has been shown in only one of its forms, it should be apparent to those skilled in the art that it is susceptible to various changes without departing from the scope of the invention. For example the retainer pin could be configured other than as a cylindrical rod. The opposed shoulders could be defined by a circular hole in the retainer pin rather than a reduced diameter cylindrical section. A single shoulder on the retainer pin that would block outward movement of the retainer pin would also be feasible.