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CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This non-provisional application claims the benefit of U.S. Provisional Patent Application No. 60/738,544, entitled “Locking Mechanism,” filed Nov. 21, 2005. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates generally to arrangements of locking mechanisms within locks and relates specifically to apparatus and methods for positioning latches and shackles within locks.  
       BACKGROUND OF THE INVENTION  
       [0003]     Locks and other securing devices are designed and used to secure all types of objects and spaces against unauthorized access. Locks are commonly used to secure containers, such as lock boxes, lockers, and cabinets, or areas, such as rooms, buildings, and fenced in yards. All locks are designed to be resistant to unlocking without an authorized key, combination, code, or other such authorizing mechanism. It is desirable to develop improvements to existing apparatus and methods for preventing unauthorized entry into a container, area, and the like secured by a lock.  
       SUMMARY OF INVENTION  
       [0004]     This invention and disclosure are directed to apparatus and methods for securing a lock from being unlocked by an unauthorized method or mechanism. Apparatus and methods are disclosed herein regarding positioning of shackles and latch members of locking mechanisms.  
         [0005]     An embodiment of the invention provides for a lock comprising a lock housing, a shackle, a locking mechanism, and a shackle biasing member. The shackle is moveably coupled to the lock housing and includes a recess. The lock mechanism is assembled in the housing and includes a latch member and a stop. The latch member is selectively engageable by a surface defined by the recess. The stop member selectively limits the movement of the latch member. The shackle biasing member biases the shackle in a first direction such that the surface defined by the recess engages the latch member to inhibit movement of the latch member with respect to the shackle and lack body and prohibit movement of the shackle in the first direction with respect to the lock body when the shackle is in the locked position. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0006]     In the accompanying drawings, which are incorporated in and constitute a part of this specification, embodiments of the invention are illustrated, which, together with a general description of the invention given above, and the detailed description given below serve to illustrate the principles of this invention. The drawings and detailed description are not intended to and do not limit the scope of the invention or the claims in any way. Instead, the drawings and detailed description only describe embodiments of the invention and other embodiments of the invention not described herein are encompassed by the claims.  
         [0007]      FIG. 1  is a perspective view of a lock constructed in accordance with an embodiment of the present invention including a shackle spring and showing an internal locking mechanism;  
         [0008]      FIG. 2  is a cross-sectional view of the lock of  FIG. 1 , showing the lock in a locked and latched state;  
         [0009]      FIG. 2A  is a detailed view of the area designated by a dashed circle in  FIG. 2 ;  
         [0010]      FIG. 3  is a cross-sectional view of the lock of  FIG. 1 , showing the lock in an unlocked and latched state;  
         [0011]      FIG. 4  is a cross-sectional view of the lock of  FIG. 1 , showing the lock in an unlocked and unlatched state;  
         [0012]      FIG. 5  is a cross-sectional view of the lock of  FIG. 1 , showing the lock in a locked and unlatched state;  
         [0013]      FIG. 6  is a cross-sectional view of a lock without a shackle spring, showing the lock in a locked and unlatched state; and  
         [0014]      FIG. 7  is a cross-sectional view of the lock of  FIG. 6 , showing the lock in a locked and latched state. 
     
    
     DETAILED DESCRIPTION  
       [0015]     This Detailed Description of the Invention merely describes embodiments of the invention and is not intended to limit the scope of the claims in any way. Indeed, the invention as described by the claims is broader than and unlimited by the disclosed embodiments and the language used in this specification, and the terms used have their full ordinary meaning.  
         [0016]      FIGS. 1-5  illustrate an embodiment of a lock and locking mechanism for positioning a shackle and a latch member. While the illustration is directed at a specific combination lock, the features of the present invention could be applied to other locks, such as for example padlocks, illuminating combination locks, door locks, locker locks, and keyed locks.  
         [0017]      FIG. 1  illustrates a perspective view of a lock  10  with internal components of the lock  10  shown. The lock  10  as shown has a lock body or lock housing  12  and a shackle  14 . The shackle  14  is generally u-shaped and includes a long leg  16  and a short leg  18  joined by a connector portion  20 . The shackle is coupled to the lock body  12  such that the shackle  14  is moveable with respect to the lock body  12 . This shackle movement is generally upward or downward, with respect to  FIG. 1 .  
         [0018]     Throughout the range of motion of the shackle  14 , the long leg  16  remains partially located within the body  12 . The long leg  16  passes into the body  12  through a long leg aperture  22 . The short leg  18  is selectively partially located within the body  12 . As the shackle  14  moves upward, with respect to  FIG. 1 , the full length of the short leg  18  may exit the body  12 . When the full length of the short leg  18  is located outside the body  12 , the shackle  14  can be passed through a hasp or other such structure to secure a container, area, or the like. The short leg  18  enters and exits the body  12  through a short leg aperture  24 .  
         [0019]     Although the embodiment of  FIG. 1  shows a shackle  14  where the long leg  16  remains at least partially within the body  12  throughout its full range of motion, it should be understood that a shackle may be arranged such that the shackle fully exits the body upon movement of the shackle with respect to the body.  
         [0020]     As will be described in greater detail below, the lock  10  includes a shackle spring  26 . The shackle spring  26  is selectively in contact with a bottom surface  28  of the long leg  16  of the shackle  14 . When the shackle spring  26  is in contact with the shackle  14 , the spring  26  biases the shackle  14  in an upward direction, with respect to  FIG. 1 . When the lock  10  is in a locked state and the shackle  14  is latched, as shown in  FIG. 1 , the biasing force of the shackle spring  26  forces the shackle  14  upward until the shackle  14  can no longer move upwards with respect to the body  12 .  
         [0021]     The lock  10  typically has a locked state and an unlocked state. In the locked state, a portion of the short leg  18  of the shackle  14  is located within the body  12  and the short leg  18  is secured in the body  12  by a locking mechanism. As best illustrated by  FIG. 2 , the locking mechanism includes a latch member  30 , a latch housing  32 , and a latch spring  34 . The latch member  30  is at least partially positioned within a chamber  36  defined by the housing  32 . The latch spring  34  is positioned between an inner surface  38  of the chamber  36  and the latch member  30 . The latch member  30  is arranged to be moveable with respect to the chamber  32 . The latch spring  34  is a compression spring and when the spring  34  is compressed, it biases the latch member  30  and encourages the latch member  30  to move out of the chamber  36  in a direction towards the short leg  18 . The latch housing  32  is pivotally coupled to the body  12  at a pivot point  37 . A spring or other biasing member (not shown) is coupled to the housing  32  and biases the housing  32  in a clockwise direction, with respect to  FIG. 2 .  
         [0022]     The latch member  30  includes a latching portion  40  that engages with the short leg  18  to secure the short leg  18  within the body  12 . The latch member  30  also includes a protrusion  42 . The protrusion  42 , to be discussed in detail below, selectively limits the movement of the latch member  30  with respect to the latch housing  32  and the shackle  14 .  
         [0023]      FIGS. 1 and 2  show the lock  10  in a locked state. As shown, the latch member  30  secures the short leg  18  within the body  12  such that movement of the shackle  14  with respect to the body  12  is resisted. The short leg  18  defines a recess  44  that serves as a catch for the latching portion  40  of the latch member  30 . As best seen in  FIG. 2A , the latching portion  40  is positioned in the recess  44  such that a generally flat surface  45  of the latching portion  40  engages a surface  46  of the recess  44 . This engagement is such that the shackle  14  cannot be moved upward without displacing the latch member  30 . Since the latch member  30  is positioned within the latch housing  32 , which is pivotally coupled to the body  12 , the latch member  30  can be displaced by counterclockwise rotation of the latch housing  32 .  
         [0024]     Referring again to  FIGS. 1 and 2 , when the lock  10  is in the locked state, counterclockwise rotation of the latch housing  32  is resisted by the arrangement of components within the lock  10 . As shown, the housing  32  includes a tail portion  47 . The tail portion  47  is positioned proximate to a combination cam  48 , which includes a groove  50 . Any combination cam known in the art can be used in the practice of this invention. When the lock  10  is in a locked state, the groove  50  is positioned to be out of alignment with the tail  47 . When the shackle  14  or body  12  is manually pulled and the shackle  14  attempts to displace the latch member  30 , the tail  47  of the housing  32  comes into contact with the cam  48  and counterclockwise rotation of the housing  32  is resisted. Thus, the short leg  18  remains secured within the body  12 .  
         [0025]      FIGS. 3 and 4  illustrate the lock  10  in an unlocked state after an operator has properly rotated a combination dial mechanically attached to the cam  48 . In  FIG. 3 , the lock  10  is unlocked and the short leg  18  remains within the lock body  12 . In  FIG. 4 , the shackle  14  is in the process of moving upward to move the short leg  18  out of the body  12  and open the lock. As shown in  FIG. 3 , when the lock  10  is in the unlocked state the groove  50  in the cam  48  is aligned with the tail  47  of the latch housing  32 . As shown in  FIG. 4 , as the shackle  14  moves upward, the engagement of the recess  44  and the latching portion  40  causes the latch member  30  to be displaced and the latch housing  32  rotates counterclockwise. Because the groove  50  is aligned with the tail  47 , the tail  47  can enter the groove  50  to accommodate this counterclockwise rotation. Thus, the short leg  18  displaces the latch member  30  and can exit the body  12 , effectively opening the lock  10 . Once the short leg  18  exits the body and is no longer in contact with the latch member  30 , the spring or other biasing member coupled to the housing  32  urges the housing  32  to rotate in the clockwise direction and return to approximately the position shown in  FIG. 3 .  
         [0026]     When the full length of the short leg  18  is outside the lock body  12 , the lock  10  can be locked by moving the short leg  18  back into the body  12 . As shown in  FIG. 5 , the combination cam  48  is positioned so that the groove  50  is not aligned with the tail portion  47  of the latch housing  32 . As the shackle  14  is moves downward and back into the body  12 , an angled surface  52  of the short leg  18  contacts a matching angled surface  54  of the latching portion  40 . The contact of the angled surfaces  52  and  54  causes the latch member  30  to retract into the chamber  36 . As the latch member  30  retracts into the chamber  36 , the latch spring  34  compresses. The movement of the latch member  30  allows for the short leg  18  to pass by the latch member  30  and be located in a position to be secured. Once the short leg  18  passes the latch member  30 , the compression of the latch spring  34  biases the latch member  30  towards the short leg  18  and the latch portion  40  moves into engagement with the recess  44 . This engagement secures the short leg  18  within the body  12  and locks the lock  10 .  
         [0027]     Referring again to  FIG. 5 , if the latch member  30  were not able to move into the chamber  36 , the short leg  18  could not pass by the latch member  30  and the lock  10  could not be closed and locked. The latch member  30  and the chamber  36  are sized such that the latch member  30 , including the protrusion  42 , can be accommodated within the chamber  36 . However, while the lock  10  is in a locked state with the short leg  18  secured within the body  12 , if the latch member  30  is allowed to substantially move into the chamber  36 , the lock  10  could be opened without placing the lock  10  in an unlocked state. Referring to  FIG. 6 , the recess  44  of the short leg  18  is located within the lock body  12  at a position where the leg  18  is normally secured. However, the latch member  30 , including the protrusion  42 , is retracted an increased distance into the chamber  36 . In this arrangement, the shackle  14  can be moved upward and the lock  10  opened, even though the lock  10  is in a locked state. As described above, when compressed the latch spring  34  biases the latch member  30  towards the short leg  18 ; however, under certain conditions, the latching portion  40  may still not engage with the recess  44  even though the leg  18  is in position to be secured. One method of at least temporarily creating such a condition is to apply an impact on the outside of the body  12 . If an impact is properly directed to the side of the body  12 , the inertia of the latch member  30  or other components could cause the latch spring  34  to compress and the latch member  30  to retract into the chamber. This could allow unauthorized opening of the lock  10 .  
         [0028]     Such conditions are normally prevented by the protrusion  42  on the latch member  30 . As best shown in  FIG. 2 , the protrusion  42  is designed to engage the latch housing  32 , with a surface  56  of the housing  32  acting as a mechanical stop. When the protrusion  42  is positioned proximate to the housing surface  56 , the engagement of the protrusion  42  and the housing surface  56  prevents the latch member  30  from substantially retracting into the chamber  36  and the latching portion  40  from disengaging from the recess  44 . Thus, even a properly directed impact on the side of the body  12  would not cause the spring  34  to compress and the latch member  30  to retract into the chamber  36 , preventing the security of the lock  10  from being jeopardized. However, as shown in  FIG. 7 , the latch member  30  can be positioned such that the protrusion  42  is not positioned proximate to the housing surface  56  and will not engage with the housing surface  56  when the latch member  30  is urged to move further into the chamber  36 . As previously described, the latch member  30  and chamber  36  are sized such that the latch member  30 , including the protrusion  42 , can be accommodated in the chamber  36 . When the protrusion  42  is outside of the chamber  36 , this sizing ensures that there will be a gap  58  between the latch member  30  and the chamber  36 . As shown in  FIG. 2 , the gap  58  can be below the latch member  30  or, as shown in  FIG. 7 , the gap  58  can be above the latch member  30 , during operation of the lock  10 .  
         [0029]     This gap  58  is necessary for the lock  10  to perform properly. The gap  58  allows for some clearance room between the latch member  30  and the chamber  36 . This clearance room is needed so that the protrusion  42  can be selectively positioned proximate to the housing surface  56  to engage with the housing surface  56  or selectively positioned such that the latch member  30 , along with the protrusion  42 , can be accommodated in the chamber  36 . As described above and shown in  FIG. 2 , when the lock  10  is secured, positioning the protrusion  42  proximate to the housing surface  56  to engage with the housing surface  56  can restrict unauthorized opening of the lock  10 . Also as described above and shown in  FIG. 5 , when the short leg  18  moves into the lock body  12 , the latch member  30  and the protrusion  42  retract into the chamber  30  to allow the short leg  18  to pass by the latch member  30  and be secured within the body  12 .  
         [0030]     As shown in  FIGS. 6 and 7 , when the short leg  18  located in the lock body  12  and the gap  58  is above the latch member  30 , the lock  10  is susceptible to unauthorized opening. Thus, maintaining the gap  58  below the latch member  30  can reduce the possibility of unauthorized opening of the lock  10 . One method of encouraging the latch member  30  to be positioned so that the gap  58  is located below the latch member  30  is through the inclusion of the shackle spring  26 . As discussed above and shown in  FIGS. 1 and 2 , a shackle spring  26  is placed in contact with the bottom surface  28  of the long leg  16  of the shackle  14 . The spring  26  is arranged to apply a force to the shackle  14  in the locked state that biases the shackle  14  upwards, with respect to  FIGS. 1 and 2 , until the shackle  14  cannot move upwards with respect to the body  12 . This force is transferred from the recess  44  in the short leg  18  to the latching portion  40  of the latch member  30 . The transferred force encourages the latch member  30  upward, leaving the gap  58  below the latch member  30  (as best seen in  FIG. 2 ). In this arrangement, the protrusion  42  is positioned proximate to the housing surface  56  such that the protrusion  42  will engage the housing surface  56  to inhibit the movement of the latch member  30  if the latch member  30  attempts to retract into the chamber  36 . The spring force of the shackle spring  26  can be designed such that the latch member  30  is pressed against an inner surface of the chamber  36 . In this arrangement, in addition to the protrusion  42  inhibiting movement of the latch member  30 , frictional forces between the latch member  30  and the inner surface of the chamber  36  inhibit movement of the latch member  30  with respect to the chamber  36  and the shackle  14 .  
         [0031]     The embodiment illustrated in  FIGS. 1-5  shows the shackle spring  26  as a lever spring. It should be understood that a variety of spring and other mechanisms could be used to bias the shackle  14  in the upward direction, with respect to  FIG. 1 . These mechanisms include, but are not limited to, coil springs arranged in either compression or extension, torsion springs, leaf springs, or any other mechanism that applies a force to the shackle such that the latch member  30  is positioned to inhibit the latch member  30  from retracting into the chamber  36  when the lock  10  is in a locked state and the short leg  18  is secured. Additionally, the shackle spring  26  is shown in direct contact with the long leg  16  of the shackle  14 . It should be understood that a spring could be in contact with the short leg  18 , any other part of a shackle, or in contact with the latch member. Further, the contact between a spring and the shackle could be indirect as well as direct.  
         [0032]     Further, the shackle spring  26  has a bent end  60  at the point of contact with the long leg  16 . This bent end  60  reduces the likelihood that the spring  26  will dig into the bottom surface  28  of the leg  18  and damage the long leg  16  of the shackle  14 .  
         [0033]     In one embodiment the range of motion of a shackle is approximately ⅝ inches. In this embodiment, a shackle spring remains in contact with the shackle for approximately ⅜ inches of this range of motion. In this arrangement, once the lock is placed in an unlocked state, the shackle has a tendency to spring or pop open due to the biasing force of the shackle spring. In other embodiments, a shackle spring may remain in contact with a shackle during the entire range of motion or may remain in contact for only a short distance of the range of motion.  
         [0034]     Typically, gravitational forces are relied upon to pull the lock body  12  downward, with respect to the lock  10  shown in  FIG. 7 . Gravitational forces are typically large enough to cause the recess  44  to force the latch member  30  into a position where the gap  58  is below the latch member  30 , as shown in  FIG. 2 . However, an arrangement where the gap  58  is above the latch member  30  when the short leg is secured, as shown in  FIG. 7 , can occur in a number of ways when a shackle spring  26  is not used.  
         [0035]     One example of an arrangement that can cause the gap  58  to be situated above the latch member  30  is when the tolerances between the diameter of the short leg aperture  24  and the diameter of the short leg  16  are very small. One technique of opening a lock without the proper authorization is to insert an object between the short leg and the short leg aperture and pry the short leg such that the recess moves away from the latch member. As the short leg is pried, the recess may disengage with the latching portion, which would leave the short leg unsecured and allow the lock to be opened. To combat this situation, the tolerances between the diameter of the short leg  18  and the diameter of the short leg aperture  24  can be tightened. This arrangement makes it more difficult to insert an object between the short leg  18  and aperture  24  by which to pry the short leg  18  and open the lock  10 . The tolerances can be tight enough to cause a slight friction fit or interference fit between the short leg  18  and the aperture  24 . Interference between the short leg  18  and the aperture  24  can also be caused if the leg  18  is slightly bent. This friction fit can resist the gravitational forces that normally urge the lock body  12  downward and, thus, the body  12  can remain positioned higher than normal and cause the latch member  30  to be positioned such that the protrusion  42  will not engage the housing surface  56  to stop the latch member  30  from retracting into the chamber  36 .  
         [0036]     The force that the shackle spring  26  placed on the long leg  16  of the shackle  14  may be designed large enough to overcome any forces generated by a friction or interference fit between the short leg  18  and the short leg aperture  24 . Other examples of arrangements that can lead to the gap  58  being located above the latch member  30  are build-ups of corrosion or other substances around the short leg or long leg apertures  22  and  24 , bending or other deformations of the shackle  14 , and ice or moisture gathering on lock components. The force of the shackle spring  26  is designed to account for these and other examples to maintain the gap  58  below the latch member  30  when the lock  10  is in a locked state and the short leg  16  is secured in the lock body  12 .  
         [0037]     While various aspects of the invention are described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects may be realized in many alternative embodiments not shown, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present invention. Still further, while various alternative embodiments as to the various aspects and features of the invention, such as alternative materials, structures, configurations, methods, devices, and so on may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the aspects, concepts or features of the invention into additional embodiments within the scope of the present invention even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the invention may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present invention however; such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated.

Summary:
This invention and disclosure are directed to apparatus and methods for securing a lock from being unlocked by an unauthorized method or mechanism. Apparatus and methods are disclosed herein regarding positioning of shackles and latch members of locking mechanisms. In one embodiment of the invention apparatus and methods incorporate a spring to bias a shackle within a lock. The biasing of the shackle positions a latch member in such a manner to offer greater security against unauthorized opening of a lock.