Abstract:
Devices and methods by which fiber optic connectors, and the adapters associated with them can be installed upon mounting surfaces. A termination block is described that retains a number of adapters to receive fiber optic cable connectors for interconnection and/or cross-connection with other connectors or switching equipment. The termination block has a mounting footprint that is substantially identical to the mounting footprint of an electrical punch-down block, thus permitting ease of retrofitting. Slider panels are retained within bays in a base unit to secure adapters within the base unit. The slider panels are individually moveable so that each can be slidingly withdrawn from its bay for better access to the adapter secured therewithin. In preferred embodiments, removable markers are affixed to individual slider panels and a removable cover is provided for the termination block. Methods for mounting and retrofitting termination blocks are also described.

Description:
BACKGROUND 
     The present invention is directed to devices that receive optical fiber cable connectors and permit them to be interconnected and cross-connected with other optical fiber connectors. 
     When office buildings and other structures receive incoming telecommunication lines, an interface is needed to receive the incoming lines and interconnect them with switching equipment associated with the building. Heretofore, incoming telecommunication lines have consisted of cables formed of copper wires that connect electrically with the switching equipment in the building. A typical interface consists of mounted “punch-down blocks” that receive the copper wires of the cables within V-shaped grooves to establish an electrical connection. Standard punch-down block designs are commonly referred to as type 66 and type 110 punch-down blocks. These devices have distinctive “footprints” that permit them to be readily installed into standard panels or spaces for installation of these racks. 
     As fiber optic-based communications have developed, it has become apparent that there is a need to be able to retrofit office buildings and other structures so that they can receive and make use of telecommunication lines made up of fiber optic cables. Up until now, those who have dealt with the problem of installing fiber optic-based cables in office buildings for telecommunications have had to install the connectors and associated adapters in fixed or sliding panels that were most often enclosed in sheet metal housings. 
     Recently, an optical distribution frame was developed that permits adapters for optical connection to be affixed within drawers in a storage rack. While this arrangement provides clear advantages over the use of metal housings, it is not ideal in every instance. First, shelves are used to mount these adapters, and these shelves must be individually withdrawn from the utility rack in order to access the adapters. Additionally, the utility rack is large—around seven feet tall—and requires room adjacent the rack so that the drawers can be withdrawn from the rack. 
     It would be an improvement to have a termination block that is compact and can be easily installed in a small area. It would also be an improvement to have a termination block that can be readily and easily substituted for standard copper electrical conduit punch-down blocks, for example, by providing the same or substantially the same footprints as the punch-down blocks. 
     SUMMARY OF THE INVENTION 
     The present invention provides devices and methods by which fiber optic connectors, and the adapters associated with them can be easily installed upon panels, walls, or other mounting surfaces. A termination block is described that retains a number of adapters to receive fiber optic cable connectors for interconnection and/or cross-connection with other connectors or switching equipment. The termination block has a mounting footprint that is substantially identical to the mounting footprint of an electrical punch-down block, thus permitting ease of retrofitting. The modular termination block also has a low production cost in comparison to prior art devices and arrangements. 
     In an exemplary described termination block, slider panels are retained within bays in a base unit to secure adapters within the base unit. The slider panels are individually moveable so that each can be slidingly withdrawn from its bay for better access to the adapter secured therewithin. In preferred embodiments, removable markers are affixed to individual slider panels and a removable cover is provided for the termination block. Methods for mounting and retrofitting termination blocks are also described. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a base unit used in the termination block of the present invention. 
     FIG. 2 is a plan view of the base unit depicted in FIG.  1 . 
     FIGS. 3 and 4 are isometric views illustrating insertion of a slider panel into the base unit of FIGS. 1 and 2. 
     FIGS. 5 and 6 are isometric views showing insertion of an adapter into a slider panel. 
     FIGS. 7 and 8 are isometric views depicting attachment of a removable marker to the slider panel, 
     FIG. 9 is an isometric view of an exemplary base unit having a plurality of slider panels and adapters installed. 
     FIGS. 10 and 11 are isometric views of the assembly depicted in FIG. 9 having a plurality of fiber optic connectors installed therein. 
     FIG. 12 shows use of an exemplary cover with the assembly shown in FIGS. 10 and 11. 
     FIG. 13 depicts an exemplary mounting arrangement for a plurality of connection blocks. 
     FIG. 14 is a closer view of a portion of a column of connection blocks. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Some of the devices constructed in accordance with the present invention are referred to herein as “termination blocks” because they are useful for receiving the terminal ends of external fiber optic communication and/or data conduits. Referring first to FIGS. 1 and 2, an exemplary base unit  10  is shown that is used in forming a termination block. The base unit  10  is also visible in FIGS. 3-12. The base unit  10  has a flat, substantially rectangular lower platform  12  that is elongated to provide longitudinal sides  14  and ends  16 . Currently preferred dimensions for the platform  12  are approximately 25 cm in length and approximately 5 cm in width to substantially match the size of a standard mounting block for electric cables such as the S66M1-50 block (or “66-block”) available from The Siemon Company. It is noted that the platform  12  might also be constructed to have the same dimensions as the S110M1-50 punch-down block (or “110-block”). 
     The longitudinal sides  14  present a rectangular tabs  18  and connector brackets  20 , 22  that extend outwardly from the sides  14 . The tabs  18  and the connector brackets  20 , 22  are used to secure the base unit  10  to a mounting surface such as a wall or panel. The dimensions of the platform  12  and the presence of the tabs  18  and connector brackets  20 , 22  define a mounting footprint for the base unit  10 . 
     The two tabs  18  are identical. The connector brackets  20  and  22 , however, are dissimilar in construction. The first connector bracket  20  has an aperture  24  disposed within it in a longitudinal direction while the connector bracket  22  has an aperture  26  disposed within it in a lateral direction. A slot  28  is cut along the majority of the length of the platform  12 . 
     Each end  16  of the platform  12  has an end panel  30  that lies flush with the end  16  and extends vertically upwardly from the platform  12 . The end panels  30  have vertically oriented retaining grooves  32  disposed within them. The upper end of each end panel  30  also has a pair of outwardly extending ears  34 . 
     Between the end panels  30 , a plurality of brackets  36  are positioned in a spaced relation from one another. The brackets  36  extend upwardly from the platform  12 , thereby defining a series of bays  38  therebetween. Bays  38  are also formed between the brackets  36  and the end panels  30 . The brackets  36  are formed by a pair of legs  40 ,  42  that are affixed to the platform  12  on either side of the slot  28  and joined to one another at their highest point  43 . A vertically oriented slot  44  is defined between the legs  40 ,  42  of each of the brackets  36  below the point of joining  43 . The vertical slots  44  are aligned with the slot  28  within the platform  12 . As will be described shortly, the brackets  36  retain a plurality of slider panels  50 . 
     Referring now to FIGS. 3 and 4, the insertion of an exemplary slider panel  50  into a bay  38  of the base unit  10  is shown. The slider panel  50  is formed from a vertically oriented plate  52  and a horizontally oriented top plate  54 . The upper surface of the top plate  54  provides a convenient surface for writing or the placement of markings or other indicia, such as labels for identification of particular cable connections. The vertical plate  52  is essentially a flat rectangular member that contains a large aperture  56  and a smaller aperture  58  that is best seen in FIG.  7 . The top plate  54  provides a finger lift for the slider panel  50  so that the panel  50  may be lifted and slidingly withdrawn from its bay  38 . 
     The lateral sides of the vertical plate  52  have slider portions  60  that are sized and shaped to fit within the vertical slot  44  of a bracket  36  or the groove  32  in an end panel  30 . A shoulder  62  is provided at the upper end of each slider portion  60 . It is pointed out that the slider panels  50  are shaped and sized to fit within the bays  38  of the base unit  10 . 
     As can be seen by reference to FIGS. 3-5, the slider panels  50  are disposed below the platform  12  and slidingly inserted from the lower side of the base unit  10  through the slot  28  and into the individual bays  38 . This method of insertion is particularly advantageous since it will be difficult to inadvertently remove a slider panel  50  from its bay  38  once the base unit  10  has been secured to a mounting surface. 
     Referring now to FIGS. 5,  6  and  7 , an adapter  64  is shown being disposed within the large aperture  56  of the slider panel  50 . The adapter  64  has an outer, block-like housing  66  having an enlarged portion  68  at one end and a smaller portion  70  at the other end. An enlarged receptacle  72  (as illustrated in FIGS. 5-7) is disposed in the enlarged portion  68  (see FIGS.  5  and  6 ), and a smaller receptacle  74  is disposed in the smaller portion  70  (see FIGS. 7,  8  and  9 ). It is noted that the adapter  64  may be configured, if desired, to receive MT-RJ connectors or another type of connector on both or either of its ends. Although not shown, it should be understood that the adapter  64  defines a passage therein between the two receptacles  72 ,  74  so that transmitted light may pass entirely through the adapter  64 . 
     The smaller portion  70  of the housing  66  is shaped and sized to be slidingly inserted into the large aperture  56  of the slider panel  50 . The upper side of the smaller portion  70  presents an outwardly protruding tab  76  having a slanted, forward-facing cam surface  78  and a vertically-oriented, rearward-facing stop face  80 . The lower side of the housing  66  is also provided with a hinged or cantilevered latch (not shown) of a type known in the art that can be depressed to facilitate sliding insertion of the smaller portion  70  of the housing  66  into the large aperture  56 . FIGS. 5-7 illustrate this sliding insertion. When inserted, the upper edge of the large aperture  56  slips over the cam face  78  of the tab  76  so that the adapter  64  is retained within the large aperture  56 . Contact by the stop face  80  with the edge of the large aperture  56  prevents the adapter  64  from being easily removed from the aperture  56 . 
     The enlarged receptacle  72 , as shown in FIGS. 5 and 6, is shaped and sized to receive and retain a FirstLink™ connector. As FIGS. 5 and 6 show, the enlarged receptacle  72  has a main entrance portion  82  and a pair of key ways  84  located on either lateral side of the main entrance portion  82 , these being formed to receive portions of a FirstLink connector when that connector is seated therein. 
     The smaller receptacle  74  is shaped and sized to receive and retain a standard MT-RJ connector of the type commonly used on the end of an optical fiber cable. The receptacle  74  also has a main entrance portion  86  for reception of the body of an MT-RJ connector and a single key way  88  located on the upper side of the main entrance portion  86  that receives the key and latch of an MT-RJ connector. The construction and operation of MT-RJ and FirstLink-style connectors and receptacles for receiving them are well understood and, therefore, will not be described in any detail here. 
     FIGS. 7 and 8 depict the attachment of a removably affixable marker  90  to a slider panel  50 . The marker  90  is used to affix a particular symbol, word, numeral, icon or other indicia to the slider panel  50 . For example, a marker might carry the symbol for a telephone (see FIG. 9) indicating that optical fiber cables connected through that particular slider panel are used for transmitting telephone communications. The exemplary marker  90  shown in FIGS. 8 and 9 has a panel  92  with a pair of attachment prongs  94  (visible in FIG. 7) affixed thereto. The panel  92  provides a surface  96  for the placement of a desired indicia. The indicia might be placed upon the surface  96  by stamping, engraving, writing, labeling or by other techniques. 
     The marker  90  is affixed to a slider panel  50  by disposing the prongs  94  within the smaller aperture  58  to provide an interference fit between the components. If it is desired to remove the marker  90 , the marker  90  is pulled outwardly to remove the prongs  94  from the aperture  50 . Because the marker  90  can be removed and replaced with another marker, remarking of the slider panels  50  is a simple matter. 
     The above-described operations can be repeated in order to install other slider panels  50 , adapters  64  and markers  90  in each or some of the bays  38  of the base unit  10 . FIG. 9 shows a slider panel  50  and an adapter  64  present in each of the bays  38  of the base unit  10 . Those of skill in the art will understand that it the adapters  64  may be inserted within the slider panels  50  either before or after the base unit  10  has been affixed to a support surface as will be described shortly. 
     Referring now to FIGS. 10 and 11, a plurality of standard MT-RJ connectors  98  are shown disposed within the smaller receptacles  74  of the smaller portion  70  of the adapters  64 . Although not shown, it will be understood that each of the connectors  98  is affixed to the end of an optical fiber cable. A plurality of connectors  100 , the illustrated connectors being FirstLink connectors, are disposed within the larger receptacles  72  of the larger portion  68  of the adapters  64 . 
     As depicted in FIGS. 10 and 11, the slider panels  50  can be pulled upwardly and slidingly withdrawn from the bays  38  to provide better access to the adapter  64  and the connectors inserted within it. Upward movement of the slider panel  50  is halted when the shoulders  62  of the slider portions  60  contact the joined portion  43  of the brackets  36 . 
     FIG. 12 illustrates the placement of a removable cover  102  onto the base unit  10 . The cover  102  is provided with a pair of notches  104  at either longitudinal end which are sized and shaped to retain the ears  34  of the end panels  30 , such retention removably securing the cover  102  to the base unit  10 . The cover  102  serves the function of protecting the adapters  64 , connectors  98  and associated components from dust and other contaminants. The cover  102  is also useful to provide a clean and neat appearance by concealing the connectors and other components from view as well providing a convenient surface for marking or labeling. 
     Termination blocks of the type described above may be installed in an equipment rack, in a frame, or directly to a wall or other mounting surface. Referring now to FIGS. 13 and 14, features of an exemplary mounting and/or retrofitting process are described. It is a feature of the invention that the termination block apparatus is capable of easily replacing a standard punch-down block, such as the S66M1-50 block. Since the exemplary termination block has substantially the same mounting dimensions as the standard 66-type copper punch-down block, it may be used in most any mounting configuration, using the same mounting accessories, as the punch-down block. 
     FIG. 13 depicts an exemplary wall type mounting arrangement wherein several columns  110  of optical fiber retainer assemblies  112  are affixed to a wall or other flat surface  114 . Six exemplary columns  110  of retainer assemblies  112  are illustrated. In each column  110 , four retainer assemblies  112  are aligned in an end-to-end relation along the wall  114 . At the lower end of each column  110  of retainer assemblies  112 , an optical fiber “D-ring” bracket  116  and a slack storage hub  118  are mounted. It is noted that the D-ring bracket  116  has upper and lower connecting portions (see FIG. 14) that present arcuate inner surfaces  120  shaped to have a sufficiently large radius to ensure that an optical fiber following the contour of the surface  120  is not bent beyond its critical bend radius. Above each of the columns  110 , a strain-relief bracket  122  is mounted for securely holding a bundled optical fiber cable. 
     Although not shown, it should be understood that, prior to affixing the retainer assemblies  112  in the pattern shown, copper cable punch-down blocks and associated equipment were removed from the surface  114 . The punch-down blocks provided the same mounting footprint as the retainer assemblies  112  and were arranged in the column pattern shown in FIG.  13 . Also, standard copper cable D-rings (not shown) were removed and replaced with the optical fiber D-rings  116  described above. Standard D-rings used with copper cable are generally unsuitable for use with optical fibers because they provide small, narrow engagement portions, and an optical fiber contacting those portions will be easily bent beyond its critical bend radius, thereby impairing or destroying the ability of the optical fiber to transmit light. Once the punch-down blocks have been removed and the copper cable D-rings replaced with optical fiber D-rings  116 , the columns  110  of connector retainer assemblies  112  are installed in the arrangement shown. 
     FIG. 14 is a closer view of the upper portions of two of the columns  110 . As shown there, a bundled optical fiber cable  124  extends downward along the wall  114 . The bundled cable  124  has an outer sheath  126  that covers a plurality of two-fiber cables  128 . The optical fiber connector retainer assemblies  112  each include a termination block  130  of the type described earlier having base unit  10 . In the illustrated embodiment, the retainer assemblies  112  also include a stand-off frame  132  of a type known in the art. 
     The stand-off frame  132  provides an upper mounting surface  134  and apertured sides  136  that define a space  138  beneath the mounting surface  134 . The apertured sides  136  of the frame  132  permit cables  128  to pass beneath the mounting surface  134 . The stand-off frames  132  are affixed to the wall  114  by screws  139  that pass through flanges  140  that extend outwardly from the sides of the stand-off frame  132 . 
     In the arrangement depicted in FIG. 14, the termination blocks  130  are mounted atop each of the stand-off frames  132 . The blocks  130  are secured to the frames  132  by means of snap tabs  142  that secure the sides  14  of the platform  12  of the termination block  130  by engaging the rectangular tabs  18  along the sides  14 . The snap tabs  142  are provided with a tapered camming surface  142   a  and a stop face  142   b  that is directed in an opposite direction. As the platform  12  is pushed downwardly onto the mounting surface  134  of the frame  132 , the rectangular tabs  18  engage the camming surface  142   a  and urge the snap tabs  142  outwardly permitting the tabs  18  to slip past the camming surface  142   a . At this point, the tab  18  will be prevented from a reverse movement by engagement of the tab  18  with the stop face  142   b.    
     It is pointed out that, if desired, the stand-off frame  132  may alternatively be omitted and the termination block  130  mounted directly to the wall  114 . When this mounting arrangement is used, it is preferred that screws or other connectors be disposed through the slots  24 , 26  in the connector brackets  20 ,  22  as such mounting may take advantage of using pre-drilled screw holes used for previously attaching a copper cable punch-down block to the wall  114 . 
     As illustrated in FIG. 14, a portion of the outer sheath  126  is removed from the bundled fiber  124  proximate the securing bracket  122 , and the individual fibers  128  are disposed through the apertured sides  136  of the stand-off frames  132 . The fibers  128  are run beneath the upper end of the top stand-off frame  132  and then routed to where they are needed. One fiber  128  is shown in FIG. 14 run through one side  136  and then looped upwardly where the affixed connector  144  is inserted into an adapter  146  in the termination block  130 . Fibers  128  may also be run down through the column  110  and through the D-ring bracket  116  to an adjacent location (not shown). Excess lengths of optical fiber may be wound around the slack hubs  118 . 
     While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes within departing from the scope of the invention.