Abstract:
This invention is directed to a cleaning insert and cleaning assembly to remove debris or contaminants from optical fiber connectors including connectors attached to system backplanes. The cleaning insert is treated with a cleaning agent such as an adhesive. The cleaning insert is secured in a cleaning assembly that is coupled to the connector to be cleaned. The treated cleaning insert contacts the ferrule of the optical fiber connector to remove the contaminants.

Description:
BACKGROUND 
     This invention relates to a cleaning apparatus for fiber optic connectors. 
     Optical fibers are quickly replacing wires for the transmission of data in the electronics industry. Not only are the fibers small, but light data transmission rates are very high in comparison to those of wire connections. Fiber optic cables may contain one or more of these optical fibers. Connectors are used to mate several optical fibers or cables as well as connect such cables to backplanes and system cards of computer and telecommunication systems. 
     Such optical fiber connectors are shown in PCT publication WO/98/00741 and in FIG. 1 on the present application. Within this connector  100 , a ferrule  112  precisely positions a plurality of optical fibers  108  for mating with fibers in a similar ferrule of a mating connector. The ferrule end faces are finely polished to minimize distance between the fibers on each ferrule  112 . A spring in each mating connector  100  biases the ferrules  112  together. Optionally, one of the two mating connectors  100  may contain alignment pins  106  on opposite sides the ferrule  112 . 
     A problem exists with these connectors in that dust and debris deposited between mating ferrules can contaminate the connectors and reduce or prohibit the transmission of light therebetween. Accordingly, there is a need to clean optical fiber connectors, but cleaning the connectors may be difficult especially when a cable needs to be removed from the system to perform the cleaning procedure. 
     For example, in large telecommunication systems an entire backplane supports attachment of numerous optical fiber cables. System cards are slid on rails and then plugged into the backplane assembly. Many of these cards contain one or more system card optical connector housings to connect the optical fiber cables mounted on the backplane to the system card. Not only are many of these cables in the backplane difficult to access, but removal of a cable is time consuming and therefore may prove financially prohibitive. 
     Therefore, there is a need for a cleaning tool that can remove dust and debris from a fiber optic cable connector particularly where removal of the cable is difficult. Further, there is a need to clean multiple optical fiber optic connectors mounted on a backplane simultaneously. There is also a need to clean similar fiber optic connectors on system cards. 
     SUMMARY 
     It is therefore an object of this invention to provide a cleaning tool for removing debris and dust from a connector. 
     It is further object of the invention to remove small pieces of debris and dust from an optical connector using a cleaning assembly which is a matable to a contaminated optical connector. 
     Another object of the invention is to provide a cleaning kit to clean optical fiber cables attached to a system backplane. 
     These and other objects have been achieved by providing a cleaning insert for use in a cleaning assembly. The cleaning insert has a main body with a cleaning pad secured on one end and a latching mechanism on the opposite end. A cleaning agent is applied to the cleaning pad and the cleaning insert is secured in a housing to form a cleaning assembly. The cleaning assembly is matable with an optical connector to be cleaned. 
     Other objects and advantages of the cleaning assembly and method will become apparent to those skilled in the art upon reading the detailed description. 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention will now be described by way of example with reference to the accompanying drawings of which: 
     FIG. 1 is a three-dimensional view of a prior art optical connector. 
     FIG. 2 is a three-dimensional view of the cleaning assembly and cleaning insert of the present invention. 
     FIG. 3 is a cross-sectional view taken along the line  3 — 3  of FIG. 2 showing the cleaning apparatus of the present invention. 
     FIG. 4 is a three-dimensional view of an alternative embodiment of the cleaning insert. 
     FIG. 5 is a three-dimensional view of a daughter card cleaning kit. 
     FIG. 6 is a three-dimensional view of an alternate daughter card cleaning kit. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present invention will be described with reference to the drawing figures where like numerals represent like elements throughout. Although the embodiment illustrates cleaning a particular type of optical fiber connector, the present invention is applicable to other connectors by minor modifications. 
     The invention will first be described generally with reference to FIG. 2. A cleaning assembly  10  being matable with and having features similar to the connector  100  of FIG. 1 contains an insert holder  20  in place of the ferrule  112 . The insert holder  20  is biased toward the mating end  12 . An opening  22  is formed in the insert holder  20 . A cleaning insert  30  fits within the opening  22 . 
     Each of the major components will now be described in greater detail with reference to FIGS. 2 and 3. Beginning with the cleaning assembly  10  and referring first to FIG. 3, the major components include an outer housing  40 , and inner housing  50 , an insert holder  20 , a spring  60 , and a rear plug  70 . Referring to FIG. 2, the outer housing  40  features a grip portion  42  extending from a rear end  44  toward the mating end  12 . A plurality of cams  46  are positioned around a window  48 . The inner housing  50  is slidingly positioned within the outer housing  40  and projects from the window  48  and the mating end  12 . The inner housing  50  features a first latching shoulder  52  positioned near the mating end  12  and a second latching shoulder  54  positioned within the window  48 . A latch  56  also extends from the inner housing  50  at the mating end  12 . Returning to FIG. 3, an insert stop  58  extends inward near the mating end  12  and a pair of openings  59  are disposed near the rear end  44 . 
     The insert holder  20  has an opening  22  which extends rearward from the mating end  12 . As best shown in FIG. 3, a pair of projections  24  extend inward from side walls  26  and are positioned within the opening  22 . Each projection  24  has a rear shoulder  28 . A wide portion  29  is disposed at the rear end  27  of the insert holder  20 . A spring  60  is positioned against the rear end  27  of the insert holder  20 . It should be understood by those reasonably skilled in the art that while a coil spring is shown here, other shaped springs or biasing devices which are well-known in the art could be substituted. The rear plug  70  features a narrow portion  72  and a wide portion  74 . An opening  76  extends through both the narrow and wide portions  72 , 74 . A pair of latching projections  78  extend outward from the narrow portion  72 . A shoulder  79  is positioned on an outer surface at the transition between the wide and narrow portions  74 , 72 . 
     The cleaning insert  30  will now be described in greater detail with reference to FIGS. 2 and 3. Projecting rearward from a main body  31  are a pair of resilient legs  32 . Each resilient leg  32  has a projection  34  extending outward near a free end  37 . A taper  38  extends from the free end  37  to the projection  34 . The cleaning pad  36  is positioned on the main body  31  opposite the resilient legs  32 . The cleaning pad  36  is formed of a resilient/compliant material to conform to the mating surface of a ferrule  112  to be cleaned. The material selected should not apply undue pressure on that mating surface. A suitable material for the cleaning pad  36  is acrylic foam. Depending upon the cleaning agent  37  used, another suitable material for the cleaning pad  36  is a low residue felt. A cleaning agent  37  is applied to the cleaning pad  36  opposite the main body  31  and a protective cover  39  is positioned over the cleaning agent  37 . The cleaning agent  37  is preferably a slightly tacky adhesive material such as White PET 550 Adhesive. The material selected should have the ability to lift debris from the surface to be cleaned yet not leave any residue. Alternate materials such as isopropyl alcohol with a felt cleaning pad  36  could be utilized as a cleaning agent as long as the material is capable of capturing debris without leaving a residue. 
     Assembly of the major components will now be described in greater detail again with reference to FIG.  3 . First, the inner housing  50  is inserted into the outer housing  40 . Next, the insert holder  20  is inserted into the inner housing  50  until the wide portion  29  engages the insert stop  58 . The spring  60  is inserted against the rear end  27  of the insert holder  20 . The rear plug  70  is inserted such that the latching projections  78  reside within openings  59  and the shoulder  79  is positioned adjacent to rear end of the inner housing  50 . 
     The cleaning insert  30  is preferably molded such that the main body  31  and resilient legs  32  are integral. Next, the cleaning pad  36  is fixed to the main body  31  preferably utilizing an adhesive. The cleaning pad  36  could be applied utilizing other methods known to those skilled in the art such as a tongue and grove joint. Next, the cleaning agent  37  is applied to the end of the cleaning pad  36 . The cleaning agent  37  is preferably another adhesive which is less tacky than the adhesive utilized to fix the cleaning pad  36  to the main body  31 . Alternate cleaning agents include fluids such as alcohol or distilled water. Those skilled in the art will appreciate that the cleaning agent  37  should be selected to be compatible with the material selected for the cleaning pad  36 .The completed cleaning insert  30  is then inserted into the opening  22  of the insert holder  20  from the mating end  12 . The tapers  38  first engage the projections  24  of the insert holder  20  to urge the resilient legs  32  of the cleaning insert  30  toward each other during insertion. The cleaning insert  30  is further urged into opening  22  until projections  34  pass over projections  24  and lock behind rear shoulders  28 . 
     An alternate cleaning insert  130  is shown in FIG.  4 . This cleaning insert  130  is similar to the embodiment of FIG. 2 except that pin receiving passageways  132  extend through the main body  131  and slits  134  are formed in the cleaning pad  136 . The slits  134  are aligned with the pin receiving passageways  132 . Each of the pin receiving passageways  132  is preferably tapered to be larger adjacent cleaning pad  136  and smaller adjacent the resilient legs. 
     In use, either a cleaning insert  30  or an alternate cleaning insert  130  is inserted into the insert holder  20  of a cleaning assembly  10 . The protective cover  39  is then removed from the cleaning pad  36 . Next, the cleaning assembly  10  is mated with an optical connector  100  such as the one shown in FIG.  1 . In this particular case, an alternate cleaning insert  130  should be utilized to receive alignment pins  106 . It should be understood however that the alternate cleaning insert  130  could be utilized to clean either a connector with alignment pins  106  or a connector without alignment pins  130 . The cleaning pad  36  contacts the end face of the ferrule  112 . Upon unmating, any debris present on the ferrule  112  will stick to the cleaning pad  36  and removed with the cleaning assembly  10 . It should be understood by those reasonably skilled in the art that while the cleaning insert  30  and cleaning assembly  10  are shown as being generally rectangular, this concept is equally adaptable to other optical connectors. For example, a cleaning insert utilizing the concepts of this invention could be adapted for use in other commercially available optical connectors such as those having round or other shaped cross sections. 
     The cleaning assembly  10  is adaptable for use in cleaning optical connectors mounted within a backplane assembly. Daughter cards are typically insertable into a backplane assembly along guide rails. Each daughter card may be configured to mate with several optical connectors mounted within the backplane assembly. One example of the daughter card cleaning kit  600  is shown in FIG.  5 . Here, a coupling housing  604  is mounted along an edge of a daughter card  602 . The cleaning assembly  10  is secured within the coupling housing  604 . The cleaning insert  30  is inserted into the mating end of the cleaning assembly  10  as described above. A plurality of spare cleaning inserts  606  are mounted to the daughter card  602 . The cleaning insert  30  may be removed and replaced by one of the spare cleaning inserts  606 . 
     Another example of the daughter card cleaning kit  700  is shown in FIG.  6 . This daughter card cleaning kit  700  is similar to the one shown in FIG. 5 except that several coupling housings  704 ,  706 , and  708  are strategically mounted along the edge of the daughter card  702  to mate with optical connectors within a backplane assembly. Cleaning inserts  30  are similarly mounted to cleaning assemblies  10  which are secured within respective coupling housings  704 , 706 , 708 . Similar spare cleaning inserts  710  are provided. In operation, either of these daughter cards  602 , 702  are slid into a backplane assembly along guide rails until the cleaning assemblies  10  are mated with complimentary optical connectors within the backplane. The daughter cards  602 , 702  are then removed and debris is removed from the complimentary optical connectors as described above.