Patent Publication Number: US-6209369-B1

Title: Key actuated exterior cam lock

Description:
BACKGROUND OF THE INVENTION 
     This invention generally relates to locks; and, more particularly, it relates to key actuated cam locks. There has been a problem related to conventional locking systems in that outside use of these locking systems results in lock malfunction when the locking system is exposed to the elements and other harsh environmental conditions. A conventional key actuated cam lock designed for outside applications can pass less than 240 hours of salt spray testing prior to malfunctioning. 
     Exemplary conventional locks and keys are disclosed in U.S. Pat. No. 4,006,616 to Rubner et al., U.S. Pat. No. 4,425,770, U.S. Pat. No. 4,099,398 to Lipschutz, U.S. Pat. No. 4,715,201 to Craig, U.S. Pat. No. 5,199,285 to Lin, U.S. Pat. No. 5,265,455 to Grinuner, U.S. Pat. No. 5,491,993 to Anderson, and C.T. Johnson Enterprises sales literature. All of these devices have a number of drawbacks. It is an object of the present invention to solve the problems enumerated above. 
     SUMMARY OF THE INVENTION 
     The present invention provides a key actuated cam lock. The cam lock has a corrosion resistant metal cap. A weather resistant plug cap is rotatably mounted in the corrosion resistant metal cap. The weather resistant plug cap has an opening permitting the entry of the key. A plug body is located adjacent to the plug cap. The plug body has a key entering end and a cam actuating end, and a plurality of spring biased disc tumblers engaging the key when the key is inserted into the plug body. The cam lock also has a lock housing so that the plug body is rotatably positioned within the lock housing. The lock housing has at least one limit stop disposed thereon. 
     The plug body has an internal O-ring providing a weather resistant seal located near the cam actuating end of the plug housing. The O-ring is disposed between the cam actuating end of the plug body and the lock housing. The cam actuating end of the plug body is connected to a corrosion resistant metal stop plate engaging the limit stop upon rotation of the plug body. A rotatable cam is connected to the cam actuating end. 
     It is an object of the present invention to greatly reduce the replacement cost associated with the use of key actuated cam locks in exterior applications and to increase operability of key actuated cam locks in corrosive or harsh environmental conditions. 
     The objects and features of the present invention, other than those specifically set forth above, will become apparent in the detailed description of the invention and drawings set forth below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a key actuated cam lock; 
     FIG. 2 is a front view of the key actuated cam lock of FIG. 1; 
     FIG. 3 is a side view of the key actuated cam lock of FIG. 1; 
     FIG. 4 is a rear view of the key actuated cam lock of FIG. 1; 
     FIG. 5 is a side cross sectional view of the interior lock housing of the key actuated cam lock of FIG. 1; and, 
     FIG. 6 is an exploded perspective view of the key actuated cam lock of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An exploded perspective view of key actuated cam lock of FIGS. 1-4 is provided in FIG.  6 . Key actuated cam lock  100  is plated with duplex nickel chrome, and includes corrosion resistant metal cap  3 . Metal cap  3  has a flat top surface  3 A which is provided by a circular rim  3 B having an aperture  3 C extending there through. Within metal cap  3  is a tapered inner bore  3 D which decreases in diameter from the bottom end  3 E of metal cap  3  to a flat interior surface  3 F. Corrosion resistant metal cap  3  is selected from the group consisting of a stainless steel cap, a brass cap, a copper alloy cap, and a galvanized metal cap. It is appreciated that other metals that are resistant to corrosion can be used. Corrosion resistant metal cap  3  has weather resistant plug cap  4  rotatably mounted therein. 
     Plug cap  4  has an opening  16  permitting the entry of key  2  through plug cap  4  and into plug body  9 . Plug body  9  is disposed adjacent to and in back of plug cap  4 . Plug body  9  has key entering end  17  and cam actuating end  18 . Plug body  9  is preferably adapted to receive double bitted reversible key  2 . In this variant, plug body  9  has apertures  27  disposed on the top and bottom of body plug  9  as required to accommodate springs  7  and disc tumblers  8 . Between key entering end  17  and cam actuating end  18  on plug body  9 , a plurality of springs  7  bias disc tumblers  8 . Disc tumblers  8  engage key  2  when key  2  is inserted into plug body  9  and either open or lock key actuated cam lock  100  as required. Disc tumblers  8  and springs  7  are protected from the elements by dust shutter  6  which is biased in a closed position by spring  5  until opened by key  2 . 
     Plug body  9  is disposed and rotatably positioned in lock housing  11 . Lock housing  11  has a conical head  26  with an aperture  26 A extending therethrough. Conical head  26  further has a rim  26 B at its top end  26 C. When cam lock  100  is assembled, with plug  9  within housing  11  and plug cap  4  seated over key entering end  17  of plug  9 , a weather resistant, water tight seal is provided. Lock housing  11  has at least one limit stop  19  at the distal end  25  of lock housing  11 . Preferably, there are at least two limit stops  19  diposed on distal end to permit stop plate  12  to rotate through a predetermined range of motion. Corrosion resistant metal stop plate  12  is selected from the group consisting of a stainless steel stop plate, a brass stop plate, a copper alloy stop plate, and a galvanized metal stop plate. 
     Plug body  9  has an internal O-ring  10  providing a weather resistant seal located near cam actuating end  18  of plug body  9 . Preferably, O-ring  10  is disposed between cam actuating end  18  of plug body  9  and lock housing  11 . Plug body  9  has annular recess  22  disposed substantially near cam actuating end  18 . Annular recess  22  is dimensioned to sealably receive O-ring  10  so that O-ring  10  prevents water from penetrating the lock cylinder. 
     As shown in FIG. 5, lock housing interior portion  23  has a complementary annular recess  24  disposed thereon for sealably receiving O-ring  10 . It is appreciated that rotation of plug body  9  in lock housing  11  is permitted with sealing being provided by O-ring  10 . Entry of unwanted debris and the elements is eliminated through the use of O-ring  10 , and the combination of the other features of key actuated cam lock  100 . 
     Corrosion resistant metal stop plate  12  is a stainless steel stop plate in one embodiment of the invention. It is appreciated that the components of key actuated cam lock  100  are made of various types of corrosion resistant metals. The corrosion resistant metals are selected from the group consisting of stainless steel and brass, but other alloys are contemplated to be used therein. A particularly advantageous plating which is found to produce unexpected results includes a duplex nickel plating. 
     Optionally, threads  20  are located on an exterior portion of housing  11 . Threads  20  are sized, positioned, constructed and arranged for threaded insertion into an aperture (not shown) in the object to be locked (not shown). A complementary nickel plated body nut  15  capable of engaging and mating with threads  20  is used to securably mount lock housing  11  to the object to which the key actuated cam lock  100  is being attached. The object fits between body nut  15  and the conically shaped portion  26  of housing  11 . Body nut  15  is a hex nut as illustrated in FIG.  1 . 
     Cam actuating end  18  is a square shape or other appropriate geometric shape for actuating and mating with stop plate  12  and cam  13 . End  18  has sem screw matable portion  21  which has threads complementary to sem screw  14 . In a preferred embodiment of the invention, sem screw  14  is nickel plated. Sem screw  14  secures stainless steel stop plate  12  and cam  13  to plug body  9 . Optionally, cam  13  is a duplex nickel plated cam. 
     In another preferred embodiment, cam lock  100  comprises stainless steel stop plate  12 , brass interior components, a nickel plated hex body nut  15 , a nickel plated sem screw  14  and, a duplex nickel plated cam  13 . 
     O-ring  10  is made from a flexibly resilient polymeric material. It is optionally made from a material that is self-lubricating. O-ring  10  can be made of a natural or synthetic rubber as required. Most preferably, the O-ring  10  is made of a salt resistant polymeric material. 
     The invention also provides a method of manufacturing a weather resistant exterior cam lock  100 . The method includes plating at least two components of cam lock  100  with a corrosion resistant metal. The components include cap housing  3 , weather resistant plug cap  4 , an openable dust shutter  6 , which is optionally biased closed by spring  5 , plug body  9 , springs  5 ,  7 , disc tumblers  8 , lock housing  11 , metal stop plate  12 , and rotatable cam  13 . The method includes providing a weather resistant seal, which optionally includes O-ring  10 , located near cam actuating end  18  of plug body  9 ; and, assembling a few or all of components  3 - 24 , in combination, to obtain weather resistant exterior cam lock  100 . 
     The Applicant has discovered that the method described herein and the combination of preferred components of key actuated cam lock  100  result in a key actuated cam lock that has superior performance capabilities over conventional key actuated cam locks. These superior performance capabilities include the ability to maintain proper function after over about 480 hours of salt spray testing. Conventional cam locks generally malfunction after about 240 hours of salt spray testing. The present invention has an operable internal and external mechanism for actuating cam lock  100  long after conventional cam locks freeze up in similar test conditions. 
     These unexpected results are seen in situations where the plating of components of cam lock  100  includes duplex nickel chrome plating. Preferably, the cam lock includes a stainless steel stop plate  12 ; brass plug body  9 ; nickel plated hex nut  15 ; nickel plated sem screw  14 ; duplex nickel plated cam  13 ; and, a weather resistant seal that comprises an O-ring  10 . 
     While only a few, preferred embodiments of the invention have been described hereinabove, those of ordinary skill in the art will recognize that the embodiment may be modified and altered without departing from the central spirit and scope of the invention. Thus, the preferred embodiment described hereinabove is to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced herein.