Abstract:
A system comprises a plug locking assembly and a key. The plug locking assembly comprises a cover for receiving and holding a plug comprising a latch and a latch support surface positionable under the latch. A rotatable cam comprising a stop surface and a slot may carry the latch support surface and may interact with a cam latch comprising an arm. The arm is alternately positionable to abut the stop surface and to lie within the slot. The key may comprise a shaft, a key tab and a limit tab. The key mates with a key receiving member associated with the cover. The limit tab is positioned on a top surface of the shaft and helps prevent over-rotation of the latch support member.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/147,599, filed Jun. 27, 2008, which claims the benefit of U.S. Provisional Application Ser. No. 60/947,831, filed Jul. 3, 2007, the subject matter of which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a plug locking assembly and, more particularly, to a plug locking assembly comprising a cover and a securement feature for locking a plug into position within a jack. The invention also relates to a system comprising a plug locking assembly and a key for manipulating the plug locking assembly. 
     BACKGROUND 
     Modular connections often rely on the use of plugs secured within jacks. The plugs typically comprise a latch that secures the plug within the jack. The latch may be depressed to disengage the plug for easy removal from the jack, allowing disconnection of a device from a network without using tools. In some cases, the latch may be accidentally depressed or unauthorized users may tamper with the latch, resulting in unwanted removal of the plug from the jack. 
     There is a need, therefore, to protect plugs and prevent their unintended disconnection from associated jacks. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an improved plug locking assembly and a system for securing a plug comprising a latch into position, the system comprising a plug locking assembly and a key. 
     In one aspect, a plug locking assembly comprises a cover and a latch support surface associated with the cover. The cover comprises an opening for receiving and holding a plug comprising a latch. The latch support surface is positionable to underlie the latch of the plug when the plug is positioned within the opening of the cover, thereby resisting depression of the latch. 
     In one embodiment, the plug locking assembly may comprise a cover comprising an opening for receiving and holding a plug comprising a latch and a rotatable cam associated with the cover. The rotatable cam of this embodiment comprises a latch support surface positionable to underlie the latch of the plug when the plug is positioned within the opening of the cover and the latch support surface resists depression of the latch when the latch support surface underlies the latch. 
     In another embodiment, the plug locking assembly may comprise a cover comprising an opening for receiving and holding a plug comprising a latch, a cam associated with the cover and a cam latch. The cam may comprise a latch support surface, a stop surface and a slot. The latch support surface resists depression of the latch when the latch support surface underlies the latch. The cam latch comprises an arm alternatively positionable in a first position abutting the stop surface of the cam to prevent movement of the cam and a second position lying within the slot of the cam to allow movement of the cam. 
     The plug locking assembly may comprise various other features. The cover may comprise a key receiving member for receiving a key to change the position of the latch support surface. This key receiving member may comprise a stop surface for preventing over-rotation of the key. Likewise, the cover may comprise a stop surface to prevent movement of the latch support surface in a predetermined direction. The latch support surface may be substantially planar and positioned on a rotatable cam comprising a curvilinear surface. The latch support surface may be alternatively disposed in a first position spaced apart from the latch and a second position underlying a bottom surface of the latch and in contact therewith. The rotatable cam may further comprise a slot for receiving an arm of the cam latch to allow movement of the cam. Additionally, at least one of the rotatable cam and the cam latch may further comprise a retention tab to engage a slot positioned within the cover. 
     In another aspect of the invention, a system for securing a plug comprising a latch in position comprises a cover comprising an opening for receiving and holding the plug, a latch support member associated with the cover and a key comprising a shaft, a key tab and a limit tab. The cover also comprises a key receiving member for receiving a key. The latch support member prevents substantial movement of the latch with the plug positioned within the cover. The key tab of the key is designed for mating with the key receiving member and the limit tab is positioned on a top surface of the shaft to prevent over-rotation of the latch support member. 
     The system may also comprise additional features. The key tab may be positioned at one end of the key and extend from a first end to a second end with a curvilinear surface connecting the first and second ends. The shaft of the key may be hollow and comprise an internal projection for engaging the key. The limit tab may comprise an angled surface. The key receiving member may comprise a key retention lip for securing the key in the key receiving member. The key receiving member may also comprise one or more limit stops and a key tab slot for receiving the key tab. In addition, all of the elements of the plug locking assembly, including a rotatable cam and a cam latch may be incorporated into the system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of the plug locking assembly of the present invention; 
         FIG. 2  is an exploded view of  FIG. 1  shown with a key used in connection therewith; 
         FIG. 3  is a perspective rear view of the cover of  FIG. 1 ; 
         FIG. 4A  is a perspective view of one embodiment of the cam component of  FIG. 1 ; 
         FIG. 4B  is a side elevated view of  FIG. 4A ; 
         FIG. 4C  is a side elevated view of an alternate embodiment of  FIG. 4A ; 
         FIG. 5  is a perspective view of the cam latch component of  FIG. 1 ; 
         FIG. 6  is a perspective view of the cam and cam latch components of  FIGS. 4C and 5  in an assembled state; 
         FIG. 7A  is a perspective view of  FIG. 1  with a plug installed within the plug locking assembly; 
         FIG. 7B  is a cross section of  FIG. 7A  through the axis of rotation of the cam; 
         FIG. 8  is a perspective view of the key of  FIG. 2 ; 
         FIG. 9  is a perspective view of the key of  FIG. 2  engaged within the cam assembly of  FIG. 6 ; 
         FIG. 10  is a front perspective view of  FIG. 1 , shown with the tool of  FIG. 2  and the cam component of  FIG. 4A  disposed in a first position; 
         FIG. 11  is front perspective view of  FIG. 10 , with the cam component disposed in a second position; 
         FIG. 12  is a front perspective view of  FIG. 1 , shown with a plug in a locked position; and 
         FIG. 13  is a bottom perspective view of  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1-6 , plug locking assembly  8  of the present invention comprises cover  10 , cam  30  and cam latch  50 . Locking assembly  8  may be used in connection with key  70  for rotating cam  30 . The foregoing components may be made of a variety of materials, including metal and plastic, and may be constructed by methods known to those skilled in the art, including machining and injection molding. 
     Referring now to  FIGS. 3 and 7A , cover  10  comprises opening  12 , sized and shaped for receipt of a plug, opposing sidewalls  14 , internal bottom surface  15 , key receiving member  16  for receiving key  70 , cam retention slot  26  (shown in  FIG. 7A ) and side stop surface  28  (also shown in  FIG. 7A ). Internal bottom surface  15  may comprise retaining latch  23 , defined by inclined surface  24  and front stop surface  25 . Retaining latch  23  secures the plug within cover  10 . Key receiving member  16  may further comprise key retention lip  17 , limit stops  18  and key tab slot  19 . Key retention lip  17  helps secure key  70  in key receiving member  16  during rotation of key  70 . Limit stops  18  prevent movement of latch support surface  33  in a predetermined direction (including e.g., over-rotation), and key tab slot  19  receives key tab  72  of key  70 , as shown in  FIGS. 3 and 8 . As best seen in  FIGS. 3 and 7A , respectively, cover  10  may further comprise cam retention slot  26  for receiving and holding cam  30 . Side stop surface  28  of cover  10  prevents rotation of cam  30  in a clockwise direction. As best seen in  FIG. 1 , cover  10  may also comprise notched portion  27  to provide clearance for certain features used in VOIP phones. 
       FIGS. 4A-C  illustrate details of rotatable cam  30 , designed to assist in preventing depression of the latch of a plug positioned within cover  10 . Cam  30  may comprise different lengths. Short cam  30   a , shown in  FIG. 4B , comprises a relatively short plug latch support  32   a , designed for receptacles that are recessed behind a panel or frame that obstructs the area into which the cam would reach. The dimensions of short cam  30   a  may be about 0.45 inches in length. Long cam  30   b , shown in  FIG. 4C , has a relatively thick plug latch support  32   b , designed for use with receptacles that are flush or very near the face of the panel in which they are mounted. The longer plug latch support  32   b  provides extra support, which is desirable given the longer space between the center of gravity of plug locking assembly  8  and the face of the receptacle. The dimensions of long cam  30   b  may be about 0.58 inches in length. 
     Cam  30  typically comprises plug latch support  32 , slot  34 , cam latch stop  36 , keyway  38 , retention tab  40  and rotation stop  42 . Plug latch support  32  may comprise latch support surface  33  connected to curvilinear surface  35 , which extends to rotation stop  42 . Although plug latch support  32  is shown with a curvilinear surface, it may exhibit other shapes, such as rectangular. Latch support surface  33  is typically substantially planar. Cam latch stop  36  and rotation stop  42  prevent unwanted rotation of cam  30 . As best seen in  FIG. 6 , cam latch stop  36  prevents rotation of cam  30  when key  70  is not inserted into keyway  38 , through its interaction with cam latch  50 . Cam  30  may rotate freely with key  70  inserted into keyway  38 , because key  70  causes a portion of cam latch  50  to slide into slot  34 . As shown in  FIGS. 7A  and B, rotation stop  42  abuts side stop surface  28  of cover  10 , preventing rotation of cam  30  in a clockwise direction. To engage cam  30  within cover  10 , retention tab  40  engages cam retention slot  26  of cover  10 , as shown in  FIG. 7A . Under these circumstances, cam  30  is secured within cover  10  in alignment with key receiving member  16 . 
       FIG. 5  illustrates a detail of cam latch  50 , which includes sidewall  52 , retention tab  54 , front surface  56 , and latch arm  58 . Cam latch  50  is secured to cover  10  through engagement of retention tab  54  within a slot (not shown) defined within cover  10 . With cam latch  50  secured within cover  10 , front surface  56  precludes access to retention tab  54 . As previously mentioned, latch arm  58  engages stop  36  of cam  30  when key  70  is not engaged within key receiving member  16  and keyway  38 , thereby preventing rotation of cam  30  and holding plug latch support  32  in place.  FIG. 6  illustrates the relationship between cam  30  and cam latch  50 , when both are positioned within cover  10 . 
       FIG. 8  illustrates key  70 , designed to rotate cam  30  and lock/unlock plug locking assembly  8 . Key  70  includes shaft  71 , key tab  72  and limit tab  74 . Shaft  71  may be hollow and comprise internal projection  73  for mating with keyway  38 . Key tab  72  is dimensioned and shaped to mate with key tab slot  19  of key receiving member  16  of cover  10 . Key tab  72  may extend from first end  77  to second end  79  through curvilinear surface  81 . Key  70  also prevents cam  30  from over-rotation through limit tab  74 , which prevents rotation of key  70  when it strikes limit stops  18  of cover  10 . Limit tab  74  may be positioned on a top surface of shaft  71  and comprise angled surface  75 . Key  70  may further comprise core outs  85  for ease of manufacture and key break  87  to provide a break point for key  70  when severe over-rotation of key occurs. 
       FIGS. 10-12  illustrate stepwise operation of plug locking assembly  8 . 
     Securement of plug  100  within a jack (not shown) through plug locking assembly  8  is relatively straightforward. Key  70  is inserted into key receiving member  16  of cover  10 , followed by rotation in a counterclockwise direction by about 90 degrees. When key  70  is inserted into key receiving member  16  of cover  10 , it also engages keyway  38  of cam  30 , which causes key tab  72  to push latch arm  58  out of contact with stop surface  36  and into slot  34 , as shown in  FIG. 9-11 . Thus, as key  70  rotates in a counterclockwise direction, cam  30  also rotates in a counterclockwise direction, clearing opening  12  for receipt of plug  100  and positioning latch support surface  33  transverse to internal bottom surface  15  of cover  10 , as shown in  FIG. 10 . 
     Plug  100  may then be secured within opening  12 . When plug  100  is inserted into opening  12 , plug rides over inclined surface  24  and retaining latch  23  comes to rest in slot  102  of plug  100 . 
     Insertion of plug  100  into a jack may occur next. With plug  100  engaged within jack, key  70  may be rotated in a clockwise direction, such that plug latch support surface  33  underlies and contacts latch  104  to secure latch  104  into position and help prevent accidental or unauthorized depression of latch  104  as shown in  FIGS. 11 and 12 . Key  70  may then be removed from key receiving member  16 , leaving plug latch  104  engaged with plug latch support  32  and allowing latch arm  58  of cam latch  50  to once again abut cam latch stop  36  of cam  30 . In this way, locking assembly  8  secures plug  100  within jack. 
     Removal of plug  100  from jack is also possible. With plug  100  engaged within jack, key  70  is once again inserted into key receiving member  16  of cover  10  and keyway  38  of cam  30 . Rotation of cam  30  in a counterclockwise direction frees plug latch support member  32  from its position beneath latch  104  of plug  100 . Plug latch  104  may then be depressed, followed by removal of plug  100  from jack. Plug locking assembly  8  may then be removed from plug  100  by manually removing retaining latch  23  from slot  102  and pressing plug  100  out by hand. 
     While certain embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims.