Patent Publication Number: US-6209163-B1

Title: Cleaner for fiber optic connectors

Description:
FIELD OF THE INVENTION 
     This invention generally relates to the art of fiber optic connectors and, particularly, to a cleaner for cleaning a fiber optic connector such as cleaning the end of the ferrule of the connector. 
     BACKGROUND OF THE INVENTION 
     Fiber optic connectors of a wide variety of designs have been employed to terminate optical fiber cables and to facilitate connection of the cables to other cables or other optical fiber transmission devices. A typical fiber optic connector includes a ferrule which mounts and positions an optical fiber or fibers within the connector. The ferrule may be fabricated of such material as ceramic or glass filled resin. A ferrule holder or other housing component of the connector embraces the ferrule and may be fabricated of such material as molded plastic. A spring may be disposed within the housing or ferrule holder such that the ferrule is yieldably biased forwardly for engaging another fiber-mounting ferrule of a mating connecting device. 
     Such fiber optic connectors typically are connected end-to-end. In other words, two opposite end surfaces of opposing ferrules are mated to directly connect opposing end surfaces of the optical fibers to each other. The connectors should provide excellent connection characteristics. However, major problems are encountered if the ferrule end surfaces become contaminated by dust, oil or other contaminants which will cause the connection characteristics to become markedly deteriorated. 
     In order to solve the contamination problems, cleaners have been provided to clean the ferrule end surfaces of fiber optic connectors. The cleaners typically include some form of soft cloth or paper which is moved over the ferrule end surfaces. The cloth or paper may be dampened with a cleaning solution such as ethanol. Fluorocarbon gas may also be used to remove excessive ethanol and any cloth or paper dust. 
     While cleaners of the character described above have proven effective for their intended purposes, they have limitations in that the fiber optic connectors typically are “brought to” the cleaner or there is easy access of the cleaner to the connectors. In other words, the connectors are easily moved to positions in engagement with the cleaner. Such cleaners may be awkward and difficult to use and, often, are not effective where there is limited access to the connectors, such as where the connectors are located in a remote or confined area. Still further, it is difficult, if not impossible, to use most existing cleaners on the ferrule end surfaces of connectors which are mounted in adapter assemblies. The connectors must be removed from the adapters in order to be cleaned. While there are some Q-Tip type of cleaning devices to clean ferrules of connectors located in an adapter, such cleaning is very dependent on the skill of the worker. This problem equally exists when a ferrule end surface is located inwardly or recessed within a mating end face of a connector. The present invention is directed to solving this myriad of interrelated problems. 
     SUMMARY OF THE INVENTION 
     An object, therefore, of the invention, is to provide a new and improved cleaner for fiber optic connectors, particularly a cleaner for cleaning the end of a ferrule of a fiber optic connector. 
     In the exemplary embodiment of the invention, the cleaner includes a housing having a mating portion for mating the cleaner with the fiber optic connector. A supply of a cleaning medium is mounted in the housing. An advancing mechanism is mounted on the housing for advancing the cleaning medium past the ferrule end of the fiber optic connector when the cleaner is mated with the connector. 
     As disclosed herein, the mating portion of the housing is formed by a nose for insertion into a mating receptacle of the connector. The nose includes an opening in a distal end thereof and past which the cleaning medium is advanced. A backing block is mounted in registry with the opening in the nose and over which the cleaning medium is advanced past the opening. Pivot means are provided for pivotally mounting the backing block whereby the backing block can pivot to accommodate varying angles of the end of the ferrule. 
     The cleaning medium is provided herein as a cleaning tape, such as a tape fabricated of a woven fabric. A supply reel is mounted on the housing for supplying the cleaning tape. A take-up reel is mounted on the housing for taking-up the cleaning tape from the supply reel. Gear means may interconnect the supply reel and the take-up reel for conjoint rotation. A ratchet mechanism is provided for rotating one of the reels to incrementally advance the cleaning tape. A pawl is provided for preventing reverse rotation of at least one of the reels. 
     Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: 
     FIG. 1 is a perspective view of a cleaner for a fiber optic connector, according to the invention; 
     FIG. 2 is a perspective view similar to that of FIG. 1, with the cover of the cleaner removed and without a cleaning tape in the cleaner; 
     FIG. 3 is a perspective view looking at the opposite end of the cleaner from that shown in FIG. 2; 
     FIG. 4 is a vertical section taken generally along line  4 — 4  of FIG. 1; 
     FIG. 5 is a top plan view of the cleaner, with the cleaning tape shown in phantom; 
     FIG. 6 is a fragmented section through the mating nose of the cleaner inserted into a fiber optic connector assembly; 
     FIG. 7 is a fragmented perspective view of a backplane chassis system within which the cleaner has considerable utility; 
     FIG. 8 is a side elevational view of the cleaner mounted on a dummy circuit board, with the mating nose of the cleaner inserted into a connector assembly on the backplane of the chassis of FIG. 7; 
     FIG. 9 is a top plan view of the cleaner and dummy circuit board shown in FIG. 8; 
     FIG. 10 is a front elevational view of the cleaner and dummy circuit board of FIG. 8; and 
     FIGS. 11-13 are views similar to that of FIG. 8, showing the cleaner mounted at different positions on the dummy circuit board for cleaning various fiber optic connector assemblies mounted at different locations on the backplane. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in greater detail, and first to FIGS. 1-4, a cleaner, generally designated  14 , is provided for cleaning the end of a ferrule of a fiber optic connector as will described hereinafter in relation to FIG.  6 . The cleaner includes a housing  16  and a cover  18  defining an interior cavity  20  therebetween. The cover has five holes  22  (FIG. 1) for receiving appropriate screws or other fasteners insertable into five internally threaded holes  24  (FIG. 2) to hold the cover on the housing and to gain access to interior cavity  20 . The housing has four additional internally threaded mounting holes  26 , for purposes described hereinafter. Cover  18  has two holes  27  aligned with two of the holes  26  in housing  16 . Housing  16  and cover  18  may be fabricated of molded plastic, die-cast metal or other appropriate material. 
     A unique feature of cleaner  14  is the provision of a mating portion for mating the cleaner with a fiber optic connector, as will be seen hereinafter. The mating portion herein is formed by an elongated mating nose  28  which has a through passage  28   a  (FIGS. 5 and 6) and which communicates with interior cavity  20 , as at  28   b  (FIGS.  2  and  3 ). Mating nose  28  can be formed integrally with housing  16 , or the mating nose can be a separate member (as shown) having a rear end slidably mounted within a channel  30  of housing  16 . The nose is spring loaded by spring  31  located between a portion  33  of the nose and the housing  16 . The nose  28  includes a projection  35  which extends from the rear end of the nose located in channel  30 . The projection  35  engages a portion of housing  16  to retain the rear end of the nose within the channel  30 . Mating nose  28  has an opening  28   c  (FIG. 5) in the distal end of the nose. A backing block  32  is pivotally mounted by pivot trunions  32   a  press-fit within notches  34  in the end of the nose. Therefore, the backing block can pivot to accommodate varying angles of the ends of the ferrules of fiber optic connectors, as will be understood hereinafter. 
     A supply reel  36  and a take-up reel  38  are mounted within interior cavity  20  of housing  16  by a pair of bolts  40  and  42 , respectively, which are threaded into the base of housing  16 , as at  44  in FIG.  4 . The bolts are shanked, as at  46  (FIG.  4 ), to form shaft portions  40   a  and  42   a  about which the reels are free to rotate. Actually, as best seen in FIG. 4, supply reel  36  is fixed by a lock washer  48  to a gear  50 , and take-up reel  38  is fixed by a pair of pins  52  to a second gear  54 . The gears are in mesh, as at  56 . Therefore, the supply reel and the take-up reel are coupled by the gears for conjoint rotation and for free rotation about shaft portions  40   a  and  42   a  of bolts  40  and  42 , respectively. 
     Generally, an advancing mechanism is provided for advancing a cleaning medium, such as a cleaning tape, from supply reel  36  over backing block  32  in nose  28  and back onto take-up reel  38 . Specifically, the advancing mechanism is a ratchet mechanism, generally designated  58  (FIGS.  2 - 4 ). The ratchet mechanism includes a ratcheting handle  60  having an interior end  60   a  (FIG. 4) journalled for free rotation about a circular boss portion  50   a  of gear  50 . Inner end  60   a  of ratcheting handle  60  is sandwiched between gear  50  and a toothed ratchet wheel  62 . A pin  63  interlocks the gear and the ratchet wheel for conjoint rotation. A moving pawl  64  is fixed to the underside of ratcheting handle  60  by a fastener  66 . A stop pawl  68  is fixed to housing  16  in the bottom of the cavity of the housing by a fastener  70 . As seen in FIG. 5, moving pawl  64  and stop pawl  68  are angled to engage teeth  62   a  about the periphery of ratched wheel  62  to effect movement of the ratchet wheel in the direction of arrow “A” (FIG.  5 ). Specifically, when ratcheting handle  60  is moved from the full-line position to the phantom position shown in FIG. 5, moving pawl  64  will incrementally rotate ratchet wheel  62  in the direction of arrow “A” and stop pawl  68  will prevent reverse rotation of the ratchet wheel. 
     From the foregoing, it can be understood that incremental movement of ratcheting handle  60  will effect incremental rotation of both supply reel  36  and take-up reel  38 . Once the force initiating the movement of the handle is removed, the handle will be returned to its original position by a spring  51 . Specifically, ratcheting handle  60  will incrementally rotate ratchet wheel  62  through moving pawl  64 . With the ratchet wheel fixed to gear  50  by pin  63  and with gear  50  being fixed to supply reel  36  by lock washer  48 , incremental movement of ratcheting handle  60  incrementally rotates the supply reel. Continuing further, with gear  50  in mesh with gear  54  at  56 , and with gear  54  fixed to take-up reel  38  by pins  52 , incremental movement of ratcheting wheel  62  is effective to incrementally rotate take-up reel  38  in the direction of arrow “C” (FIG.  5 ). 
     With the above understanding of the advancing or ratcheting mechanism  58  of cleaner  14 , reference is made to FIG. 5 wherein a cleaning tape  70  is shown being fed off of supply reel  36  around a guide roller  72  and into through passage  28   b  of mating nose  28 . The cleaning tape is moved in a path around the front face of backing block  32  so that the cleaning tape is exposed at opening  28   c  of the mating nose. The cleaning tape then moves back through passage  28   b  into interior chamber  20  in the direction of arrow “E”, around a second guide roller  74  and onto take-up reel  38 . Therefore, a section of the cleaning tape will move past opening  28   c  of mating nose  28 , around backing block  32 , in response to each ratcheting action of handle  60 . The cleaning tape can be fabricated of woven cloth, paper or other fabric or fibrous material appropriate for cleaning the end of a ferrule of a fiber optic connector. 
     FIG. 6 shows how mating nose  28  of cleaner  14  can be mated in a receptacle  72  of an appropriate fiber optic connector assembly, generally designated  74 . Actually, the assembly includes a fiber optic connector, generally designated  76 , inserted into an adapter, generally designated  78 . Connector  76  mounts a ferrule  80  which terminates one or more optical fibers  82 . The ferrule has an end face  80   a  which can be readily cleaned by cleaner  14  of the invention. Mating nose  28  of the cleaner is inserted past a shutter  84  of adapter  78  so that opening  28   c  and backing block  32  at the distal end of mating nose  28  are juxtaposed in registry with end face  80   a  of ferrule  80 . 
     It should be understood that connector assembly  74  is but one example of the applicability or utility of cleaner  14 . It specifically can be seen that mating nose  28  of the cleaner can access ferrules which are recessed within a fiber optic connector assembly. It also can be understood that by providing mating nose  28  as a separate component from housing  16 , the nose can be interchanged with other mating noses of different configurations for different connector assemblies. FIG. 6 also shows the significance of pivotally mounting backing block  32 . In many fiber optic connectors, the end face  80   a  of ferrule  80  is maintained at an angle to the axis of optical fiber(s)  82  for mating with a similarly angled ferrule of a complementary mating connector. Pivotally mounted backing block  32  can accommodate varying angles of the ends of the ferrule. 
     FIGS. 7-13 show a system for cleaning the end of a ferrule of a fiber optic connector mounted on a backplane  86  of a card frame or backplane chassis, generally designated  88 , adapted for receiving a plurality of printed circuit boards  90 . Card frame or backplane chassis  88  includes a plurality of guide rails  92  for receiving the top and bottom edges of printed circuit boards  90 . A plurality of edge-card connectors  94  are mounted on backplane  86  in alignment with guide rails  92 . Header connectors  96  are mounted at the leading edges of printed circuit boards  90  for connection within edge card connectors  94 . Alternatively, the edge card connectors could be configured to directly engage circuit traces along the leading edges of the printed circuit boards. A plurality of fiber optic connector assemblies  74  (FIG. 6) are mounted at different locations on backplane  86  generally in alignment with guide rails  92  and edge card connectors  94  (i.e., in alignment with the leading edges of printed circuit boards  90 ). Printed circuit boards  90  have connectors mounted thereon for mating with fiber optic connector assemblies  74 . The printed circuit boards are inserted into chassis  88  in the direction of arrow “F”. 
     It should be understood that the card frame or backplane chassis described above in relation to FIG. 7 is but one application within which the cleaning system of the invention is applicable. In other words, backplane  86  is a “motherboard” and printed circuit boards  90  are “daughter boards” in the card frame or chassis of FIG.  7 . However, the cleaning system of the invention is equally applicable wherein printed circuit boards are used with connectors simply mounted on panels or frame components other than a motherboard. Therefore, the use of the term “backplane” herein and in the claims hereof is not limited to the backplane being a printed circuit board. 
     With that understanding, reference is made to FIGS. 8-10 wherein it can be seen that cleaner  14  (FIGS. 1-6) is mounted on an dummy circuit board  98  having a cut-out portion or opening  100 . Referring back to FIG. 1, housing  16  of cleaner  14  has a section  102  of reduced dimensions sized for sliding in cut-out  100  in dummy circuit board  98 . A frame piece  104  is mounted to the front of dummy circuit board  98 , and the frame piece has an elongated opening  106  through which ratcheting handle  60  of the cleaner projects. FIG. 8 shows one of the fiber optic connector assemblies  74  (FIG. 6) mounted on backplane  86  (FIG. 7) of the card frame or chassis  88 . Dummy circuit board  98  has a second cut-out  108  for accommodating connector assembly  74 . Mating nose  28  of cleaner  14  projects into cut-out  108  for insertion into connector assembly  74  to clean the ferrule thereof as described above in relation to FIG.  6 . 
     Two rows  110  of mounting holes  112  are formed in dummy circuit board  98  to mount cleaner  14  on the dummy board at different positions to accommodate fiber optic connector assemblies  74  being mounted at different locations on backplane  86 . Mounting holes  112  are located for alignment with mounting holes  26  (FIG. 2) in housing  16  of cleaner  14 . Therefore, FIG. 8 shows one position for mounting the cleaner on the dummy board to accommodate the location of connector assembly  74  in FIG.  8 . FIG. 11 shows cleaner  14  moved upwardly relative to the position of FIG. 8 by using differently positioned mounting holes  112 . FIG. 12 shows cleaner  14  moved downwardly from the position of FIG. 8 for accommodating still a differently located fiber optic connector assembly  74 . FIG. 13 shows still another position of cleaner  14  on the dummy board at the extreme top range of mounting holes  112  to accommodate a fiber optic connector assembly at still a different location on the backplane. Readily removable fasteners can be used to position in the aligned holes and easily adjust the position of the cleaner on the backplane. 
     With the system of FIGS. 7-13, it can be understood that an actual printed circuit board  90  can be removed from backplane chassis or card frame  88  (FIG. 7) to expose fiber optic connectors  74  on backplane  86 . An operator simply recognizes the location of the fiber optic connector assembly which is to be cleaned and positions cleaner  14  on dummy circuit board  98  accordingly. The dummy circuit board and the cleaner then are inserted into the position where the actual printed circuit board has been removed, and mating nose  28  of the cleaner will be inserted into the receptacle of the fiber optic connector assembly on the backplane. By ratcheting handle  60 , cleaning tape  70  will be moved over the ferrule end face of the fiber optic connector assembly to clean the ferrule as described above. After cleaning, the dummy circuit board and the cleaner are pulled out of card frame  88 , and the actual printed circuit board can be reinserted and mated with the cleaned connector assembly. 
     It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.