Abstract:
A lock assembly including a first lock portion having an open end which receives a key. The assembly further includes a second lock portion operatively connected to the first lock portion and a biasing means operatively attached to the first and second lock portions. Wherein one of the first and second lock portions is capable of biased rotational movement independent of the other of the first and second lock portions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Application No. 60/864,074, filed on Nov. 2, 2006, entitled “PRE-LOADED LOCK ASSEMBLY,” which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to a pre-loaded barrel lock and more particularly to a pre-loaded rotatable barrel lock for use in the utility industry that eliminates the need for an installation key. 
       BACKGROUND OF THE INVENTION 
       [0003]    Utility boxes, such as electric meter boxes, are typically secured to prevent unauthorized access to the meter. Many of such boxes are secured through the use of split ring that is placed directly around the meter and locked through the use of a barrel lock. Other utility boxes, referred to as “ringless” boxes, do not include a lockable meter ring. Ringless boxes are secured by placing a lock assembly containing a barrel lock on either a side wall or a bottom wall of the box. 
         [0004]    In either case, utility personal and contractors hired to install barrel locks are given security keys to do so. Each utility, however, has only one key combination so a single key can gain access to every lock in the entire system. Moreover, these keys are at times lost or stolen which creates a security problem for the utility company. 
         [0005]    Furthermore, installation with a key is slower and therefore more costly than installing a pre-loaded lock. Installation of a split ring and barrel lock with the use of a barrel lock key involves multiple steps including, inserting the key into lock, activating the key and removing the lock, installing the ring onto the meter, inserting the lock into the meter ring and reactivating and removing the key. 
         [0006]    In view of the above, known barrel locks are often preloaded into meter rings. Known preloaded locks, however, are limited to “plunger” style barrel locks. Plunger style barrel locks generally have a hollow barrel with a plunger that reciprocates axially within a bore of the barrel to lock or unlock the barrel lock. While plunger style barrel locks can offer security and variety of different lock mechanisms, design impediments exist which limit the number of possible configurations. Moreover, it may be possible to defeat plunger locks to gain unauthorized access to a meter box. 
         [0007]    Certain rotatable disk style barrel locks present a solution to the inherent limitations of a plunger style barrel lock. An example of such a lock is described in U.S. Pat. No. 5,086,631, which is hereby incorporated by reference in its entirety. Known rotatable disk barrel locks are not, however, preloadable. 
         [0008]    With the forgoing concerns in mind, it is the general object of the present invention to provide a preloaded rotatable disk barrel lock that eliminates the need for an installation key thereby providing a level of security unavailable with known locks. Moreover, it is a general object to provide a preloaded rotatable disk barrel lock which simplifies and expedites the installation process by eliminating the need for a key. 
       SUMMARY OF THE INVENTION 
       [0009]    It is an object of the present invention to provide a preloaded barrel lock. 
         [0010]    It is an object of the present invention to provide a preloaded rotatable barrel lock and other locking devices. 
         [0011]    It is another object of the present invention to provide a preloaded rotatable disk style barrel lock that eliminates the need for an installation key thereby providing an increased level of security. 
         [0012]    It is another object of the present invention to provide a preloaded rotatable disk style barrel lock that simplifies and expedites the installation process by eliminating the need for an installation key. 
         [0013]    It is an object of the present invention to provide a preloaded lock rotatable disk style barrel lock for use with utility meter boxes. 
         [0014]    It is another object of the present invention to provide a preloaded rotatable disk style barrel lock is preloaded into a split ring for installation on a utility meter box. 
         [0015]    These and other objectives of the present invention, and their preferred embodiments, shall become clear by consideration of the specification, claims and drawings taken as a whole. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view of a preloaded barrel lock in accordance with an embodiment of the present invention. 
           [0017]      FIGS. 2A-2C  are views of a split meter ring in which the preloaded barrel lock of  FIG. 1  may be employed. 
           [0018]      FIG. 3  is a cutaway perspective view of the preloaded barrel lock of  FIG. 1  illustrating a cylinder, stem and biasing means. 
           [0019]      FIG. 4  is an additional perspective view of the cylinder, stem and biasing means of the preloaded barrel lock of  FIG. 1 . 
           [0020]      FIG. 5  is an enlarged perspective view of the cylinder and stem of the preloaded barrel lock of  FIG. 3 . 
           [0021]      FIGS. 6A-6C  are various enlarged exploded views of the cylinder and stem of the preloaded barrel lock of  FIG. 3 . 
           [0022]      FIGS. 7A and 7B  are cross-sectioned, enlarged front views of the preloaded barrel lock of  FIG. 3  illustrating a rotational movement of the stem relative to the cylinder. 
           [0023]      FIG. 8  is an enlarged perspective view of the stem of the preloaded barrel lock of  FIG. 3 . 
           [0024]      FIG. 9  is an enlarged perspective view of the biasing means of the preloaded barrel lock of  FIG. 3 . 
           [0025]      FIG. 10  is a perspective view of the cylinder, biasing means and stem of the preloaded barrel lock of  FIG. 3 . 
           [0026]      FIG. 11  is a rear perspective view of the cylinder, stem and biasing means of the preloaded barrel lock of  FIG. 3 . 
           [0027]      FIG. 12  is a perspective view of a cylinder, stem and biasing means according to an alternative embodiment of the present invention. 
           [0028]      FIGS. 13A and 13B  are perspective views of the cylinder, stem and biasing means of  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Referring to  FIG. 1 , the preloaded rotatable disk style barrel lock  10  present invention includes a head portion  15  and cylindrical barrel body  20  extending therefrom. The barrel body  20  includes a cylindrical internal passageway  25 . The head portion  15  includes a series of protrusions  22  which engage a key (not shown) to prevent rotation of the entire lock  10  upon removal. As shown, the barrel body  20  further includes locking balls  30  which are situated in and protrude from radial openings  35  in the barrel body  20 . As will be appreciated, the locking balls  30  are configured to engage corresponding recesses in a locking device. 
         [0030]    More specifically, the locking balls  30  are configured to engage recesses, in, for example, known preloadable split retaining rings. As shown in  FIGS. 2A-2C , known rings  40  have a curved side wall  45  which extends from a male end  50  to a female end  55 . The female end includes an open-ended collar  60  into which a plunger-style barrel lock  65  is placed. An interior  70  of the collar  60  includes relatively shallow recesses  75  that engage locking balls to hold a lock assembly in a preloaded condition. As will be appreciated, there are other means for preloading the inventive lock, such as a collar with a straight bore as opposed to recessed  75 . 
         [0031]    The male end  50  includes a bushing  80  which can be brought into axial alignment with the collar  60 . The bushing  80  includes a second, deeper set of recesses  85  which accept the balls when the lock is pushed through the collar  60  of the female end  55  and into the bushing  80  of the male end  50  to secure the ring. 
         [0032]    As stated previously, however, the only known barrel locks that may be preloaded into such split retaining rings are plunger type locks which have potential drawbacks. In particular, plunger locks may be easier to defeat and have fewer locking combinations than rotating disk barrel locks. The present invention overcomes the potential drawbacks through the use of a preloadable, rotating disk barrel lock. It is important to note, however, that the present invention may be used with other rotating barrel locks that do not utilize disks such as a pin and tumbler type lock. 
         [0033]      FIGS. 3-4  illustrate generally the internal components of the barrel lock  10  which are housed within the head portion  15  and barrel body  20  ( FIG. 1 ). In particular, the cylindrical internal passageway  25  of the head  15  and body  20  has a series of reduced diameter sections which terminate in a narrowed blind bore  85 . Within the passageway  25  are a cylinder  90  and a stem portion  95  extending axially from the cylinder  90 . The cylinder  90  contains combination disks  100  spaced apart by washers  103 . The disks and washers, which operate to lock and unlock the inventive lock, are described more fully in U.S. Pat. No. 5,086,631, which is incorporated by reference in its entirety. 
         [0034]    The cylinder  90  also includes a hardened steel ball  105 . The ball  105  is located in a bore of the cylinder to prevent attempts to drill out the lock. As shown, the stem  95  extends from the cylinder  90  into the blind bore  85 . Importantly, the stem  95  is a separate component from the cylinder  90  and is rotatably attached to the cylinder  90  along with a means for rotationally biasing the stem  95  relative to the cylinder  90 , preferably a spring  110 . As discussed in greater detail below, the two-piece, biased cylinder  90  and stem  95  allow for relative rotational movement that, in turn, enables the lock to be preloaded. 
         [0035]    The stem  95  further includes a first or terminal end portion  112  with opposing flats  115 . When the stem  95  is rotated so that the flats  115  are beneath the balls  30 , the balls  30  are retracted into the radial openings  35 . Conversely, when the cylindrical portions  120  are beneath the balls  30 , they are biased outward from the openings  35  so that they may engage recesses in a collar  60  or bushing  80  of a split meter ring  40  ( FIGS. 2A-2C ). As will be readily appreciated, it is the rotational movement of the stem  95  that urges the balls  30  outward. 
         [0036]    Referring now to  FIG. 5 , the cylinder  90  has opposing ends. An open end  121 , which contains the combination disks and washers utilized to lock and unlock the inventive lock, and a stem end  123  which includes a machined recess  122  in which resides a bore  125 . The bore  125  serves as a means for rotatably securing the stem  95  to the cylinder  90 . As such, the bore  125  is shaped to receive a reduced diameter attachment end  124  of the stem  95 , which is opposite the terminal end portion containing the flats  115 . The bore  125  is configured to allow rotational movement of the attachment end  124 . The attachment end  124  is illustrated as being partially cylindrical with cut-away or chamfered sides, however, as will be appreciated, the attachment end  124  may be completely cylindrical as long as rotation is enabled. 
         [0037]    The attachment end  124  also terminates in a shoulder  130 . A front surface  130 A of the shoulder  130  engages an abutment surface  126  that surrounds the bore  125  ( FIGS. 6A and 8 ). The insertion of and relationship between the stem  95  and the cylinder  90  is illustrated in  FIGS. 6A-6C . 
         [0038]    Referring now to  FIGS. 5 ,  7 A and  7 B, the rotational movement of the stem  95  relative to the bore  125  is limited by two stops  135  located within the recess  122 . The stops  135  limit rotational movement of the stem  95  by contacting front  130 B and back  130 C surfaces of the shoulder  130 . The stops  135  permit the stem  95  to rotate approximately 90-degrees relative to the cylinder  90 . As such, the stem can rotate so that the flats  115  are in contact with the balls  30  to facilitate removal of the inventive lock from a split ring. 
         [0039]    As depicted in  FIG. 8 , rotation of the stem  95  relative to the cylinder is also guided by a second stem shoulder  140 , which slidably engages an outer surface on the stem end  123  of the cylinder  90  that surrounds the recess  122 . The shoulder  140  marks the beginning of a slightly wider, D-shaped stem portion  150 . The D-shaped portion  150  terminates in a flange  155 . After the flange  155 , the diameter of the stem  95  decreases and remains substantially uniform up to the flats  115  of the terminal end portion  112 . The D-shaped stem portion  150  of the stem is significant in that the biasing means  110 , again preferably a spring, that connects the stem  95  and cylinder  90  has a corresponding D-shaped end  160  ( FIG. 9 ). The D-shaped end  160  of the spring fits over the D-shaped portion  150  of the stem  95  and prevents it from moving freely within the spring  110  thereby allowing the spring  110  to exert a rotational force on the stem  95 . The D-shaped end  160  of the spring  110  abuts the flange  155  of the stem  95 . 
         [0040]    The spring  110  is more clearly illustrated in  FIG. 9 . In addition to the D-shaped end  160 , the spring  110  includes a depending leg  165 . The depending leg  165  engages a channel  170  on an exterior surface of the stem end  123  of the cylinder  90  ( FIG. 10 ). The relationship between the spring  110  and the stem  95  and cylinder  90  is depicted in  FIGS. 10-11 . More specifically, in  FIG. 10  the depending leg  165  is shown in the channel  170  of the cylinder  90 . The D-shaped end  160  of the spring  110  is shown engaging the D-shaped stem portion  150 . The spring  110  functions both as a torsion spring biasing the stem, and as a compression spring urging the combination disks toward the open end  121  of the cylinder and the stem toward the balls  30 . 
         [0041]    This biased configuration is an important aspect of the present invention as the depending leg  160  of the spring  110  in channel  170  creates resistance as the D-shaped end  160  of the spring  110  attempts to rotate the stem  95  counterclockwise to lock the inventive lock. As will be appreciated, however, the channel  170  may have various shapes and configurations as long as it can fix an end of the spring or other biasing means to the cylinder creating rotational resistance between the cylinder and stem. 
         [0042]    Moreover, as will be appreciated, the biasing means need not necessarily be a spring. For example, the stem and cylinder may be interconnected simply by a flexible or pliable material that allows for the relative rotational movement between the two components. Accordingly, depending on the configuration, it may be possible for the stem and cylinder to be unitary as long as relative rotational movement is possible. 
         [0043]    In use, the barrel lock  10  is inserted into a collar  60  of a split ring  40  and, with the use of a key, the disks are rotated counterclockwise thereby rotating the cylinder to a locked position ( FIGS. 2A-2C ). This causes the stem  95  to rotate, biasing the balls  30  outward to engage the relatively shallow recesses  75  or groove in the interior  70  the collar  60  thereby preloading the lock. In this preloaded state, the stem is not fully rotated so that the cylindrical portions  120  are directly below the balls  30 . As such, the balls  30  are not fully extended as their travel is limited by the relatively shallows recesses  75  in the collar  60 . The stem  95  is rotationally biased by the spring  110 , however, so that the balls  30  are also biased outward. 
         [0044]    In view of the above, when the bushing  80  of the male portion  50  of the split ring is axially aligned with the interior  70  of the collar  60  the preloaded lock may then be pushed into the bushing causing the already biased stem to complete its rotation until the balls  30  are completely biased outward and protrude into the deeper bushing recesses  85  or groove securing the split ring  40 . 
         [0045]    The biased rotational movement of the stem relative to the cylinder makes this possible. In particular, as stated, when the balls are in the relatively shallow collar recesses they are not completely biased outward. While they are being forced outward by the stem and action of the spring, they cannot fully extend as their travel is limited by a bottom surface of the collar recesses. This partial extension of the balls allows them to pass out of the relatively shallow collar recess and into the deeper bushing recess when a user desires to lock the split ring. Once the balls have the clearance to extend fully outward into the deeper bushing recess, the biased stem rotates and the cylindrical portions of the stem are directly below the balls biasing them completely outward and placing the split ring in a locked position. 
         [0046]    Referring back to  FIGS. 2A-2C , preloading is facilitated by the relatively shallow recesses  75  in the interior  70  of the collar  60 . The shallow recesses  75  also have a steely inclined back wall  72  and a ramp like front wall  74  that facilitates the passage of the balls  30  beyond the recesses  75  and into the bushing  80  and bushing recesses  85 . 
         [0047]    This functionality is not possible with known disk style barrel locks as they include stem portions that are rotationally fixed relative to a cylinder portion. Movement of the cylinder in these locks correspondingly moves, in a direct drive fashion, the stem so that there can be no “intermediate position” in which the balls are biased outward to partially extend into a relatively shallow collar recess where the key can be removed from the lock. 
         [0048]    To remove the inventive lock, the key is inserted and rotated. In the unlocking cycle, the cylinder and stem operate preferably, though not necessarily, in a direct drive fashion and rotation of the cylinder rotates the stem correspondingly so that the flat are directly underneath the balls and the lock may be extracted from a split ring. 
         [0049]    As will be appreciated, the barrel lock of the present invention may be partially installed within the collar of a split ring at the factory, so as to enable complete locking of the split ring in the field merely by pushing the barrel lock completely into the collar. Thus, installation time is reduced, while increasing the ease of installation. Moreover, installers of these pre-loaded barrel locks need not have access to a key to facilitate locking of the barrel lock in the field. 
         [0050]    Referring now to  FIGS. 12 ,  13 A and  13 B, illustrating an alternative embodiment of the present invention, the biasing means need not be a spring and the stem and cylinder need not be separate components for biased relative rotational movement between the components. For example, as depicted, the stem  200  and cylinder  210  may be unitary. In this case, the stem  200  is capable of rotational movement relative to the cylinder  210  due to its relative thinness and flexibility of the material of the stem  200 . Moreover, biasing is accomplished by the material of the stem  200  and the fact that the stem  200  and cylinder  210  are one-piece. Accordingly, depending on the configuration, it may be possible for the stem and cylinder to be unitary while retaining the relative rotational functionality critical to the present invention. 
         [0051]      FIGS. 13A and 13B  graphically depict how a unitary stem  200  cylinder  210  design would operate. As shown, in  FIG. 13A  the stem  200  is in a first position in which the balls (not shown) would be biased outward.  FIG. 13B  depicts the stem  200  rotated 90-degrees so that flats  215  would be beneath the balls (not shown). In this position, however, the stem  200  would be rotationally biased urging the balls outward toward a locked position while at the same time allowing the balls to be held in an intermediate biased position to facilitate preloading. 
         [0052]    In sum, the present invention provides a secure disk-style barrel lock that may be preloaded into a split ring eliminating the need for an installation key. This increases security for utilities employing such locks and provides an ease of installation. As stated, while there are known locks that may be preloaded into a split ring, all are plunger style, which can have significant limitations and drawbacks. While these drawbacks can be addressed with disk style barrel locks, no known disk style barrel lock is preloadable. Known disk locks are not preloadable, as they do not include a stem and cylinder that provide for biased relative rotational movement. 
         [0053]    While the invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various obvious changes may be made, and equivalents may be substituted for elements thereof, without departing from the essential scope of the present invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention includes all embodiments falling within the scope of the appended claims.