Abstract:
A lock for attaching a cover to a platform includes first and second pivotally mounted latch bars which spread to engage side walls of a strike opening in response to actuation of a key actuated rotatable plug mounted in the housing of the lock. The latch bars are mechanically spread to engage the strike in a positive manner and do not rely upon biasing means to maintain the lock in the locked position.

Description:
BACKGROUND OF THE INVENTION 
     In a principal aspect, the present invention comprises a lock useful for latching a cover to a platform and, more particularly, to a lock having a bolt comprised of opposed and pivoting latch members which positively lock with opposite sides of a strike opening. 
     Storage containers, hard top carriers, and various types of enclosures desirably require the use of a lock which enables lifting of an enclosure cover from a platform when the locking member of the lock is in the unlocked position and positive locking or latching of the cover to the platform when the cover is lowered against the platform to a closed position. Prior art systems which have been used for latching, for example, a car top carrier box against a platform, incorporate latching levers which are biased to a locked position by a spring member. To unlock such a mechanism it is necessary to have a means for mechanically engaging the levers and move them against the biasing force of the spring thereby releasing the latch. Should the spring break or otherwise become disabled through corrosion or due to other circumstances, the lock may become disabled. As a consequence development of a lock mechanism which does not require a spring means in order to maintain the lock in the locked position is deemed desirable. 
     Prior art patents which exemplify locks designed for such environments include U.S. Pat. No. 4,976,123 and U.S. Pat. No. 5,119,654. While such lock mechanisms are useful, there has remained a need for an improved lock mechanism particularly for use in combination with car top carriers and other types of enclosures wherein a box-like enclosure is fitted against a platform and it is desired to lock the enclosure to the platform. 
     SUMMARY OF THE INVENTION 
     Briefly the present invention comprises a lock which includes a housing that is generally planar in construction with pivotally attached first and second, planar bolt lever arms. A cylinder with a key actuated plug is also mounted in the housing in a manner which permits a rotatable stud extending from the plug to project between the two bolt lever arms. The stud is configured so that when the plug is rotated by actuation of a key, the end of the stud will engage the lever arms causing them to pivot thereby separating and positively engaging the opposite sides of a strike. The plug is constructed so that the key can be removed from the plug only when the plug is in the locked position. When in the locked position, the bolt lever arms are positively, mechanically engaged by the actuating stud and locked to the strike. Consequently, even though springs are provided to bias the bolt lever arms toward the unlocked position, failure of the springs when the lock is in the locked position will not result in failure of the lock. The lock will remain in the locked position since it is mechanically forced and maintained in that position by the projecting stud which engages the bolt lever arms. 
     The lock further includes features which facilitate its utility to hold a carrier box in combination and joined to a platform. Thus there is a protective tongue or plate associated with the housing which fits over and parallel to the bolt lever arms to protect the lever arms and prevent them from being inadvertently engaged. The geometry of the housing and the bolt lever arms is chosen so as to physically protect the lever arms and provide the most beneficial mechanical advantage when operating the lever arms. The housing is fashioned and fabricated in a manner which protects the user from the moving parts of the lock and which also enhances the ability to easily mount the lock in a manner which promotes sealing or water tight installation. 
     Thus it is an object of the invention to provide an improved lock construction for use in many environments and especially for use in combination with hard top carriers and similar types of storage assemblies. 
     It is a further objection of the invention to provide a lock which includes a mechanism for positively engaging bolt members with a strike when the lock is in the locked position. 
     Yet another object of the invention is to provide a lock which includes a minimum number of mechanical parts, which may be efficiently and easily manufactured, which is economical, and which is easy to install. 
     These and other objects, advantages, and features of the invention will be set forth in the detailed description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the detailed description which follows reference will be made to the drawing comprised of the following figures: 
     FIG. 1 is an exploded isometric view of the lock construction of the invention; 
     FIG. 2 is a plane view of the lock construction in the unlocked position; 
     FIG. 3 is a plane view of the lock in the locked position wherein the cover for the housing has been removed to illustrate the internal construction of the bolt lever arms; 
     FIG. 4 is a plane view of the front side of the lock in the unlocked position; 
     FIG. 5 is a side elevation of the lock of FIGS. 2 and 4; 
     FIG. 6 is a top plane view of the lock of FIG. 4; 
     FIG. 7 is a isometric view of the strike utilizing combination with the lock of FIGS. 1-6; 
     FIG. 8 is a lower or bottom side elevation of the strike of FIG. 7; 
     FIG. 9 is a side elevation of the strike of FIG. 7; 
     FIG. 10 is a partial sectional view of the strike of FIG. 9 taken along the line  10 — 10 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the figures, the embodiment of the invention includes a bracket  20  with first and second lever arms or latch bars  22  and  24  pivotally mounted thereon and biased respectively by springs  26  and  28  for pivotal movement toward one another about pivot connections, pivot points, or pivot support studs  30  and  32 , respectively. A protective cover  34  fits over and facilitates retention of the bolt members or latch bars  22  and  24  on studs  30 ,  32 . The lock further includes a cylinder  36  integrally cast or formed with and projecting axially from the bracket  20  transverse to the plane of rotation of latch bars  22 ,  24 . Cylinder  36  includes a rotatable plug  38  mounted for axial rotation in the cylinder  36 . The plug  38  includes a projecting, generally elliptically shaped, inner end stud  40  which is designed to cooperate and actuate the latch bars or bolts  22  and  24  as described hereinafter. A retainer clip  42  fits over the inside end of the stud  40  to retain the plug  38  rotatably mounted within cylinder  36  of bracket  20  and thereby hold the cover  34  over the bracket  20  and latch bars  22 ,  24 . 
     The bracket  20  further includes a planar, projecting tongue or plate  44  which is parallel to and fits against the latch bars  22  and  24  to provide protection during movement of those latch bars  22  and  24 . The bracket  20  further includes laterally projecting wings or arms  50  and  52  with fastener openings  54  and  56 , respectively for attachment of the bracket  20  to the inside face of a car top carrier cover or platform, as the case may be. The cylinder  36  includes an annular surface or land  58  that acts as a sealing surface for the cylinder  36  and for attachment of the bracket to a cover or platform as the case may be. Thus, as depicted in FIG. 6, the bracket  20  may be attached to a housing  60  to position the cylinder  36  including a forward section  62 , an annular seal  58  and a rear enlarged diameter section  64  with respect thereto. The wings or arms  50  and  52  include fasteners (not shown) for attachment of the lock to the housing, platform or cover  60  as the case may be. When attached as described, the latch bars  22  and  24  project or extend or pivot laterally from the sides of bracket  20  and are designed to engage with a strike  70  as illustrated in FIG. 1 wherein the strike  70  includes a strike opening  72  having opposite sides  74  and  76 . The latch bars  22 ,  24  are normally biased by springs  26 ,  28  to the position illustrated in FIG. 2 when the plug stud  40  is rotated so that the stud  40  will not engage against inside cam surfaces  23  and  25  of the latch bars  22  and  24 , respectively. Thus, the springs  26 , and  28  will bias the latch bars  22  and  24  to the position shown in FIG.  2 . The latch bars  22 ,  24  may then pass into the opening  72  of the strike  70 . The plug  38  may then be rotated to the locked position illustrated by FIG. 3 so that the latch bars  22  and  24  will spread or pivot apart, and more particularly, projecting teeth  19  and  21  of the latch bars  22  and  24  will engage through the opening  72  and engage with the opposite sides  74  and  76  of the strike  70 . The stud  40  thus provides a means for locking the latch bars  22  and  24 . 
     The plug  38  is keyed so that the key  39  can be removed only when the lock or latch bars  22  and  24  are in the latched or locked position. Otherwise, the key  39  cannot be removed from the plug  38 . 
     The cover or tongue  44  protects a user from inadvertently catching their fingers or hand in the latch bars  22 ,  24 . Additionally, the cover  44  also protects the latch bars  22 ,  24  from manipulation from the outside of the platform and serves to protect the integrity of the latch bars  22 ,  24  in the latched position. Further, in the event the springs  26  and  28  break or fail, their breakage or failure is inconsequential with respect to the maintenance of the platform or latch bars  22 ,  24  in the locked position. The stud  40  acts to engage the lock and maintain it in the locked position and the fact that it is in the locked position, does not depend upon whether the springs  26  and  28  fail. 
     In the preferred embodiment, the pivot axes of the pivots  30  and  32  are parallel and extend axially in the same direction as the axis of the plug  38 . Thus, the stud  40  and the pivot axes of the latch bars  22  and  24  are all parallel. The plug  38  may be easily removed when the assembly is exposed in that the cover  34  provides a retention space  35  for access to the retention clip  42 . By removing the retention clip  42 , one can remove the plug  38  and cover  34  and thus replace the plug  38  with a rekeyed plug  38 . Removal of the entire latch assembly is thus not necessary in order to rekey the lock. The recess  35  also serves to protect the retaining clip  42  so that it will not be inadvertently removed or engaged. The shape of retaining wall  37  about the recess  35  thus facilitates its accessibility as well as its protectability. 
     While there has been set forth a preferred embodiment of the invention, it is to be understood that the invention is to be limited only by the following claims and equivalents thereof.