Patent Abstract:
A locking device suitable for NID housing security. The device includes a slotted cylinder, a key and key tool. The slotted cylinder has a resistance component contained in the cylinder. The key is mateable with the slotted cylinder and is held in place by the force of the resistance component. The key head has a cavity therein of a complimentary shape to the key tool so that the tool may be used to turn the key for locking or unlocking. A cylindrical sleeve is used for additional security. The sleeve fits over the mated key and slotted cylinder to protect against release of the parts and may further provide a barrier to removal from a structure being locked. By use of different key head cavity shapes each subscriber may only access their own line in a NID.

Full Description:
CROSS REFERENCE TO PRIOR APPLICATIONS 
     This application is a continuation-in-part of U.S. Ser. No. 09/363,522 filed Jul. 29, 1999, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to locking devices, and more particularly to locking devices for use with network interface devices (NIDs). 
     BACKGROUND OF THE INVENTION 
     Network interface devices (NIDs) or Network Interface Units (NIUs) house telephone line junctions and terminals. As used herein, the terms NID and NIU are interchangeable. The NID may provide either residential or commercial line access to one or more subscribers. The NID is typically placed between the subscriber&#39;s wiring and the service provider&#39;s subscriber loop. 
     Typically, the NID is sectioned for separate subscriber and service provider access. Each subscriber line terminal is typically covered by a hinged plate. Subscribers or service providers can usually access their individual lines in the compartment by lifting the plate, thereby exposing the subscriber line terminal. In many configurations, the compartment for a loop junction is limited to service provider access. 
     In most NID configurations, the individual subscriber line access cover plate is designed to be readily accessed. The line access covers are typically one inch wide and two inches in length, although there are known variations to these designs. Many configurations of these covers comprise a slot through which an apertured flange fixed to the NID housing may pass. A subscriber may place a small padlock through the aperture in the flange to prevent the cover from being lifted. 
     Unfortunately, present NID designs which enable easy access by subscribers and service providers, also permit access by unauthorized persons. The relatively small sized padlocks used for this application are known to have poor tamper-resistant characteristics. Additionally, due to the size of the cover, small padlocks must be used which are often difficult to use given dexterity limitations of individuals and/or the environmental conditions (i.e. poor lighting) at the NID. Even expensive small locks having improved tamper-resistant features also present similar problems. Additional problems result when a subscriber breaks a key in the lock or is unable to use the key provided with the lock due to the poor quality of the lock and key assembly. Further, larger locks, such as those having a combination or traditionally-sized keys, are typically not an option due to the size and physical limitations of the NID enclosure. 
     Consequently, line access in NIDs remains relatively poorly secured thereby exposing the subscriber to potential costs related to repair, theft and damage, particularly for NIDs accommodating numerous subscriber junctions. 
     Accordingly, there exists a need to economically and simply secure line access in NID configurations, and the like. There exists a need to provide a tamper-resistant solution that may be used in a relatively small area. There further exists a need for a device which is easily secured and removed by an authorized user of an existing NID cover configuration without affecting the operation of neighboring subscriber covers and/or accesses. Additionally, there exists a need to provide a device that locks a subscriber&#39;s line access cover uniquely from other accesses on the same NID, thereby preventing one subscriber from accessing another&#39;s line on the same NID. 
     SUMMARY OF THE INVENTION 
     Embodiments of the invention provide a locking device that may be used to prevent a subscriber from accessing another subscriber&#39;s line on the same NID. 
     The locking device includes a slotted cylinder having a first end, a second end and a first slot. The first slot has a distal end and a proximate end. The slot&#39;s proximate end coincides with the cylinder&#39;s first end and extends from the first cylinder end longitudinally and partially toward the second cylinder end. The cylinder has a second slot extending from, and opened to, the first slot distal end at an angle to the first slot. The cylinder has a resistance component contained in the cylinder at its second end. A key, mateable with the slotted cylinder, has a shaft with a key head at the first end of the shaft. A flange extends from and at an angle to a second end of the shaft. The key head has a cavity therein. The device also includes a key tool which is mateable with the key head cavity. The key may be inserted into the slotted cylinder and turned to lock it therein. The key tool is used to release the key from the slotted cylinder. 
     A cylindrical sleeve may be utilized for additional security. The sleeve has a first end, second end, first inner diameter, second inner diameter, and a third inner diameter. The first inner diameter is larger than the outer diameter of the slotted cylinder so that the slotted cylinder may fit in the sleeve. The first inner diameter extends from the first sleeve and to a length corresponding at least to the length of the slotted portion and the slotted cylinder. The sleeve&#39;s second diameter is larger than the key head so that the key head may fit at least partially within the sleeve. The second inner diameter extends from the second sleeve end to a length of at least about the key head length. The third inner diameter is positioned between the first inner diameter and the second inner diameter. The third inner diameter is larger than the key shaft diameter and smaller than the key head so that the sleeve cannot pass over the key head. A slot extending the length of the third inner diameter section and partially into the cylinder wall accommodates the key flange when the key is placed in the sleeve. 
     By use of different key head cavity shapes each subscriber may only access their own line in a NID. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The invention is best understood from the following detailed description when read with the accompanying drawings. 
     FIG. 1A depicts a slotted cylinder according to an illustrative embodiment of the invention. 
     FIG. 1B depicts a key according to an illustrative embodiment of the invention. 
     FIG. 1C depicts a key tool according to an illustrative embodiment of the invention. 
     FIG. 2A depicts a sleeve according to an illustrative embodiment of the invention. 
     FIG. 2B depicts a cross-sectional view of a middle section of a sleeve according to an illustrative embodiment of the invention. 
     FIG. 3 depicts a slotted cylinder being engaged with a key in a sleeve according to an illustrative embodiment of the invention. 
     FIG. 4 depicts a slotted cylinder being engaged with a key in a sleeve in an aperture according to an illustrative embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the invention provide a locking device that may be used in conjunction with NIDs and may be manufactured using relatively inexpensive materials. 
     FIGS. 1A-C depict an embodiment of the invention comprising a slotted cylinder  100  and a key  102 . FIG. 1A depicts a slotted cylinder  100 . The slotted cylinder  100  has a first end  104 , a second end  106  and a first slot  108 . The first slot  108  has a distal end  110  and a proximate end  112 . The slot&#39;s proximate end  112  coincides with the cylinder&#39;s first end  104 . The slot  108  extends from the first cylinder end  104  longitudinally and partially toward the second cylinder end  106 . The cylinder  100  has a second slot  114  extending from the first slot distal end  110  at an angle  140  to the first slot  108 . The second slot  114  may be straight or arced. The cylinder  100  may be provided with a resistance component  116  which is contained in the cylinder  100  at its second end  106 . Preferably the resistance component  116  is affixed to the inside of the slotted cylinder second end  106 . 
     FIG. 1B depicts the key  102 . The key  102  has a shaft  118  with a head  120  at a first end  122  of the shaft  118 , and a flange  124  extending from, and at an angle  142  to, a second end  126  of the shaft  118 . The key head  120  has a cavity  128  operably mateable with a key tool  130 . For example, the cavity may have a star or plus shape, into which a complementaly-shaped tool may be inserted. Additional examples of cavity shapes include triangle, square, “H”, pentagon, and “T”. 
     The key tool  130  may have any overall shape that enables a user to grasp and rotate it when engaged with the key. FIG. 1C depicts an illustrative embodiment of the key tool  130  with a key tool head  136  complementary in shape to the cavity  128  shown in FIG.  1 B. They key tool  130  has a handle  132  used to turn the tool. A screwdriver-type handle in line with the key tool shaft  134  is a further example of a functional design. 
     The key flange end is inserted into the first slot  108  of the cylinder at the cylinder&#39;s proximate end  112  until it contacts the resistance component  116 . The key  102  is then moved an additional amount toward the slot distal end  110  until it encounters and compresses the resistance component  116 . Once compressed the resistance component  116  provides a force on the key  102  in a direction longitudinally along the key shaft  118  toward the slot proximate end  112 . 
     The key tool  130  is then inserted into the key head cavity  128 . Using the key tool  130 , the key  102  is rotated around an axis defined by the length of the shaft  118  so that the key flange  124  moves into the second slot  114 , thereby locking the key  102  into the slotted cylinder  100 . 
     The resistance component  116  may be any structure that would provide sufficient pressure on the key  102  so that the key  102  is not free to slide out of the second slot  114 . The resistance component  116  may be, for example, a metal coil such as a spring, rubber stop, elastomeric polymer, pliable plastic or other elastic material. 
     A further embodiment of the invention is depicted in FIGS. 2A-B and FIG.  3 . This embodiment includes a cylindrical sleeve  200  which may provide additional security. FIG. 2A depicts an embodiment of the sleeve  200 . The sleeve  200  has a first end  202  and a second end  204  and is divided into at least three sections  206 ,  208  and  210 . The first section  206  has an inner diameter L 1  which is larger than the outer diameter of the slotted cylinder  100  so that the slotted cylinder  100  may fit into the sleeve  200 . The first section  206  extends from the first sleeve end  202  to a length corresponding at least to the length of the slotted portion of the slotted cylinder  100 . The second sleeve section  208  may have a diameter L 2  which is larger than the key head  120  so that the key head  120  may fit in the sleeve  200 . Preferably the second section  208  extends from the second sleeve end  204  to a length sufficient to cover key  102  to the extent necessary to require the key tool  130  to disengage the key  102  from the slotted cylinder  100 . The key tool  130  will generally be necessary for disengagement if the key head  120  is not protruding enough from the sleeve  200  to grasp it firmly enough to turn the key  102 . The third sleeve section  210  is between the first and second sleeve sections  206 ,  208 . The inner diameter L 3  of the third section is larger than the key shaft diameter and smaller than the key head diameter. The third section  210  need only be as long as is necessary for the section to have the structural integrity necessary to provide the desired security. Too thin a third section  210  may weaken the device and not satisfactorily protect against tampering. As depicted in FIG. 2B, the third section  210  may have a slot  212  extending along the length of the section and cut partially into the cylinder wall to accommodate the key flange  124  when the key is positioned into the cylinder  100  through the sleeve  200 . The slot  212  is only necessary if the length of the flange  124  is greater or equal to the radius of the key head  120  or if additional security is desired. The reason for this will become apparent when the operation of the sleeve is described below. 
     Operation of the sleeve  200  is depicted in FIG.  3 . The key  102  is placed, flange end first, into the sleeve  200  at the sleeve second end  204 . The slotted cylinder  100  is placed, first end  104  first, into the sleeve  200  at the sleeve first end  202 . They key flange  124  is aligned with the slot  212  (not shown) in the sleeve wall of the third section  210 , if such a slot exists, as it is put through the sleeve  200 . The key flange  124  is also aligned with the first slot  108  in the slotted cylinder  100  as the key  102  enters the slotted cylinder  100 . The key  102  is pushed into the sleeve  200  and the cylinder  100  until it meets the resistance component  116 . At that point the key  102  is pushed farther until the key flange  124  reaches the second slot  114  and can be rotated so that the flange  124  is engaged with the second slot  114 . This leaves the key  102  engaged with the slotted cylinder  100  with the sleeve  200  surrounding the engaged key and cylinder. In the embodiment depicted in FIG. 3, the diameter L 3  of the third sleeve section  210  is smaller than the key head  120  or the slotted cylinder collar  220 , or both so that the sleeve  200  cannot be slid over the engaged key and cylinder. The key  102  is locked into the slotted cylinder  100  and may have the sleeve  200  over the key head  120  so that the key  102  cannot be turned without the key tool  130 . 
     FIG. 4 depicts the key  102  and the slotted cylinder  100  being slid into the sleeve  200 . In a preferred embodiment, when the key  102  is engaged with the cylinder  100 , the uncollared end of the sleeve  200  abuts the collar  220  of the slotted cylinder  100 , and the outer face of the key head  102  is nearly flush with the outer face of the collar  218 . 
     As depicted in FIG. 4, the sleeve-covered lock  410  is particularly useful in conjunction with a latch. Latch may comprise two apertured parts, a tab  402  and a lid  404 , having apertures  418  and  416 , respectively. The apertured tab  402  fits through the lid aperture  416  so that the tab aperture  418  may accommodate the sleeve-covered lock  410 . When used with such a latch, the sleeve second end  204  and the slotted cylinder second end  106  may be fashioned with collars  218  and  220 , respectively, so that the sleeve-covered lock  410  cannot be pulled through the tab aperture  418 . A comparable configuration may be used on ND cover. 
     Although suitable for communication systems having NIDs, the locking device is also usable in other devices, such as lockers, utility boxes, tool boxes, protecting units, security systems and the like. 
     The sleeve  200  may have a collar  218  on at least one end. The sleeve collar  218  provides a barrier so that the sleeve-covered lock  410  cannot be slid through an aperture. As pictured in FIG. 3, the sleeve collar  218  is not necessary at the slotted cylinder end of the sleeve if a collar  220  exists on the slotted cylinder  100 . In the embodiment depicted in FIG. 3, the slotted cylinder  100  fits into the sleeve  200  only as far as the collar  220 . Therefore, when the sleeve  200  is over the engaged key  102  and slotted cylinder  100 , there is a collar at each end of the sleeve-covered lock to keep the device from sliding through the aperture  418 . 
     In a further illustrative embodiment, such as depicted in FIG. 2A, the sleeve  200  contains two collars  218  to keep the device from sliding through the aperture. In this embodiment, the slotted cylinder  100  can be placed entirely in the sleeve  200 , providing additional security. The inner diameter L 3  of sleeve section  210  will keep the engaged key and slotted cylinder from sliding out of the sleeve  200 . 
     The sleeve  200  may function without any collar if, in addition to the slotted cylinder  100  having a collar  220 , the key head  120  is larger than the sleeve second end  204  so that the sleeve  200  cannot slide over the key  102  when the key  102  is locked into the slotted cylinder  100 . The key head  120  would have to be larger than the aperture  418  through which the sleeve-covered lock is placed. Preferably the key head  120  is very thin so it could not be easily grasped and turned without a key tool  130 . A thicker key head  120  could be used in this fashion if for example, it was convex. 
     Advantageously, one or more parts of the locking device may comprise plastic or other economical material. The locking device, however, may be made of any material that can be formed into the desired parts and that exhibits the structural integrity necessary to provide the desired security. A further illustrative example of a locking device material is metal. 
     While the invention has been described by illustrative embodiments, additional advantages and modifications will occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to specific details shown and described herein. Modifications, for example, to the shapes of the key, key tool, slotted cylinder and sleeve, and to the materials used to fabricate the device, may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention not be limited to the specific illustrative embodiments but be interpreted within the full spirit and scope of the appended claims and their equivalents.

Technology Classification (CPC): 8