Abstract:
A security lock and encasement providing resistance to torquing moment with a slip ring designed to slide onto the padlock encasement from the back without being able to advance beyond the front face of the encasement. Said slip ring is designed such that it can only be applied or removed to the lock casing from the back of the casing and is properly aligned with said encasement through a setscrew that will break if sufficient torque is applied.

Description:
[0001]    This application is a Continuation-In-Part of a co-pending Non-Provisional Application filed on Dec. 11, 2000 having U.S. application Ser. No. 09/734,491, the priority of which is claimed. 
     
    
     
       BACKGROUND  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to the field of padlocks, and more specifically to a torque-resistant protective case enclosing a lock and a shackle.  
           [0004]    2. Prior Art  
           [0005]    While padlocks generally provide a measure of security for articles being protected, they have not been a completely effective deterrent in outdoor areas prone to vandalism or in areas requiring higher security against that kind of destructive activity. In most applications, a common padlock is vulnerable to cutting tools that can cut the shackle or to other tools, such as a pipe wrench, that can break the shackle, hasp or lock through torque. Historically, the shackle has been the most vulnerable portion of the padlock.  
           [0006]    A development towards protecting the shackle was seen in U.S. Pat. No. 3,835,675 issued to Lippisch. Lippisch extended the encasing portion of the lock to cover a portion of the shackle. However, this design still left the shackles partially exposed and accessible to cutting tools. Thus, this device provided only a small amount of additional security over existing technology.  
           [0007]    Further technical advances came when the entire lock and shackle were enclosed in a cylindrical casing. The casing caused the shackle to be covered when the lock was in use and attempted to prevent access to the protected object via cutting the shackle. Several fully encased padlocks are known in prior art. These generally include a hard, fixed casing that completely covers the shackle and are described in U.S. Pat. No. 6,338,261(Liu) and U.S. Pat. No. 5,345,794 (Jenks), incorporated herein by reference.  
           [0008]    These designs solved the security problem that was caused by partially exposed shackles. However, because the design of the padlock called for the casing to be rigidly affixed to the lock, it left the lock, hasp or shackle vulnerable to attack by the application of torque, through a pipe wrench or other similar instrument. Thus, the new lock design fully enclosing the shackles was only marginally effective in deterring vandalism.  
           [0009]    In further developments, guards and encasements were added to negate the torquing problem. The “guard approach” generally involved a guard that covered the approach to the lock, but was not integrated into the lock encasement (U.S. Pat. No. 5,172,574 to Perfetto and U.S. Pat. No. 5,469,722 to Ellefsen). A rotating encasement approach is exemplified in U.S. Pat. No. 3,820,360 (Best) or U.S. Pat. No. 5,669,255 (Albano), showing a freely rotating encasement. This approach addressed the torquing problem, but left the lock subject to vandalism because the rotating encasement could be easily rotated to a position where the keyhole was covered and then the encasement affixed to that position. Additionally, the freely rotating design often left the keyhole and the encasement hole misaligned, causing an inconvenience to the lock user.  
           [0010]    However, none of the prior art has resolved the problem of protecting the hasp, which is the weakest part of the lock protection. The problem with breaking the hasp to gain entry into a locked object is that 1) unauthorized entry is allowed and 2) the process damages the thing to be protected. Thus, as vending machines become more expensive, it becomes increasingly important to protect them from damage through unauthorized entry.  
           [0011]    Therefore, what has been needed is a padlock that is resistant to cutting, resistant to the application of torque and easy to install and use.  
         BRIEF SUMMARY OF THE INVENTION  
         [0012]    According to the present invention, a padlock is described that is resistant to attach through the application of torque and is easier to use than prior art. In the preferred embodiment, a locking mechanism is housed in a cylindrical casing that encloses the locking mechanism and partially encloses the lock&#39;s shackles. The sidewall of the casing is covered by a slip ring to prevent the destruction of the lock through rotational force. When affixed to the casing, the slip ring is prevented from forward axial movement by the cooperation of offsetting outer diameters of the lock casing and the inner diameters of the slip ring. It is prevented from axial movement backwards in part by the fact that the back surface of the lock assembly abuts an immovable surface. When installed, the slip ring is inhibited from further rotational movement by a small setscrew or similar device that breaks with the application of sufficient torque. The location of the setscrew and threaded opening to receive the screw aligns the keyhole opening of the slip ring with the keyhole opening of the casing, thereby making the lock easier to use.  
           [0013]    To date, the lock has been extremely well received in the marketplace after independent testing because of the lock&#39;s ability to prevent entry by breaking the hasp. In testing in high crime areas, the invention claimed herein proved to be the only lock that did not succumb to vandalism and/or attack. Prior art lock technology in these areas had been inadequate to prevent vending machine vandalism.  
           [0014]    It is therefore an object of the present invention to provide a lock that both protects the shackles and secures the lock against breakage by torque.  
           [0015]    It is a further object of the present invention to provide a lock that is resistant to torque forced tampering through the use of a rotatable encasement/slip ring.  
           [0016]    Further features and advantages of the present invention will be appreciated by reviewing the following drawings and detailed description of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    For a further understanding of the objects and advantages of the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawing(s), in which like parts are given like reference numbers and wherein:  
         [0018]    [0018]FIG. 1 presents a perspective, from the front, of the lock casing and the slip ring;  
         [0019]    [0019]FIG. 2 presents a the rear elevations of the slip ring and lock casing of FIG. 1;  
         [0020]    [0020]FIG. 3 presents the side elevation of the encasement and the side elevation of the slip ring;  
         [0021]    [0021]FIG. 4 presents a perspective of the lock casing and slip ring as they would be positioned onto a latch; and  
         [0022]    [0022]FIG. 5 presents a perspective, from the rear, of the lock casing and the slip ring.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]    A novel torque-resistant security casing for a secure lock is described. In the following description, for the purposes of explanation, specific component arrangements, constructions and other details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent to those skilled in the art, however, that the present invention may be practiced without these specific details. In other instances, well known manufacturing methods and structures have not been described in detail so as not to obscure the details of the present invention unnecessarily.  
         [0024]    Referring to FIG. 1, a lock generally referred to with numeral  10  (not shown) is enclosed within a cylindrical padlock casing  12  having a front face  14 , a rear face  16  and a sidewall  18 . The sidewall  18  of the casing  12  has a first larger diameter  20  and a second smaller diameter  22 . The first and second diameters  20 ,  22  combine with circumference differentials within the slip ring  30  to prevent further forward axial movement of the slip ring  30  when the slip ring  30  is placed onto the casing  12  in a rear to forward axial movement. Because of the differing circumferences of the lock casing  12  and the slip ring  30 , the slip ring  30  is unable to slide onto said casing  12  in a forward to rear axial movement. In the embodiment shown, the circumferences  20 ,  22  are positioned towards the rear edge of the sidewall  18 . In an alternative embodiment, the differential circumferences  20 ,  22  are positioned towards the front edge of the sidewall  18 . While size is not a limiting factor in the invention, the preferred embodiment lock casing  12  has a diameter of approximately four inches. The material composition of the casing  12  is not a limiting factor of the invention either. However, in the preferred embodiment, the casing  12  is made of case hardened steel.  
         [0025]    Referring next to FIG. 2, the front face  14  of the casing  12  is circular and has solid surface without any openings. The rear face  16  of the casing  12  is circular and has a slightly smaller circumference than the front face  14 . The rear face  16  also has an oblong shaped shackle cut-out  40  in the opening to the rear face  16  of the casing  12  to allow a single I-shaped shackle  42  to project vertically within the shackle cut out  40 . The casing  12  surrounds and encloses the locking mechanism (seen as an outlined figure in FIG. 5), which is rigidly affixed inside the casing  12 . The casing  12  has a cavity (not shown) extending inward from the sidewall  18  (best seen in FIG. 1) to allow for the placement of a keyed tumbler cylinder locking mechanism. The keyed tumbler locking mechanism is maintained within the cavity (not shown) of the casing  12  and includes a shackle  42  and a lock housing (not shown). The shackle  42  is a single I-shaped shackle that projects from the bottom of the shackle cut out  58  upwards through the top of the shackle cut out  56 . A slip ring  30  encircles the lock casing  12 .  
         [0026]    Referring next to FIG. 3, the hollow, cylindrical slip ring  30  is slightly larger in diameter than the casing  12  and slides axially over the sidewall  18  of the casing  12 . The slip ring  30  has a third inside diameter  32  that corresponds to the first and larger outside diameter  20  of the sidewall  18  of the casing  12 . The slip ring  30  also has a fourth inside diameter  34  that corresponds to the second outside diameter  22  of the sidewall  18  of the casing  12 . When the lock  10  is fully assembled, the first and second outside diameters  20 ,  22  of the casing  12  cooperate with the third and fourth inside diameters  32 ,  34  of the slip ring  30  prevent forward axial movement of the slip ring  30  when the slip ring  30  is coupled onto the casing  12 .  
         [0027]    Referring now to FIGS. 4 and 5, the casing  12  also has a smaller threaded opening  44  in the sidewall  18  of the casing  12  for a setscrew  60  to act as an alignment guide to align to casing  12  keyhole  46  with the slip ring  30  keyhole cut out.  
         [0028]    The sidewall  18  of the padlock case  12  contains means for aligning the casing  12  keyhole opening  46  with the slip ring  30  opening. The setscrew  60  additionally prohibits the lateral movement of the slip ring  30  by affixing the screw  60  through the slip ring  30  and into a threaded opening  44  in the encasement  12 .  
         [0029]    In one embodiment, the lock  10  has a shelf  48  that extends backwards from the rear face  16 . In an alternative embodiment, the rear face  16  has a planar surface.  
         [0030]    The lock is assembled by coupling the slip ring  30  to the casing  12  by sliding the slip ring  30  axially from the rear of the casing  12  towards the front of the casing  12 . When the differing diameters of the slip ring  30  and casing  12  meet, further forward axial movement of the slip ring  30  is prohibited. The slip ring  30  properly aligns with the casing  12  by inserting the setscrew  60  into the setscrew opening  44 . The lock attaches to the device to be locked by sliding the lock axially towards the hasp  52  until the rear face  16  of the lock abuts the planar surface of the device to be locked. When the lock is fully assembled and in use, the slip ring  30  covers the sidewall  18  of the casing  12 , the rear face  16  of the casing  12  abuts the exterior wall of the item being locked, and the shackle  42  of the lock  10  attaches vertically to the hasp  52  of the item to be covered. When the lock  10  is engaged, the shackle  42  passes through a hasp  52  that is firmly affixed to the item being secured.  
         [0031]    In this manner, the casing  12  and slip ring  30  are properly aligned through the use of the setscrew and the lock  10  remains free from vandalism caused by the use of rotational/torque force.  
         [0032]    The description of the present invention has been made with respect to specific arrangements and constructions of a lock that is resistant to being broken through torque or rotational movement. It will be apparent to those skilled in the art that the foregoing description is for illustrative purposes only, and that changes and modifications can be made to the present invention without departing from the overall spirit and scope of the present invention. The full extent of the present invention is defined and limited only by the following claims.