Abstract:
A fiber optic connector fiber stub remover and method for automated fiber stub removal. The device has a top plate with a platen opening, and a platen with a well that carries a polishing film over the well. An air pocket is formed between the polishing film and the well. The platen is positioned with a top surface of the polishing film accessible via the platen opening. A fixture holds connector ends of fiber optic cables with fiber stubs extending therefrom, and a weight biases the fiber stubs into contact with the polishing film. A motor is controlled by a motor control unit to control a ramp up time and final speed of movement of the platen over a timespan. Each connector ends moves independently relative to the polishing film. The air pocket provides shock absorption of the polishing film so that an ideal pressure is exerted on each fiber stub during stub removal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application No. 61/665,782 filed Jun. 28, 2012. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates generally to the field of manufacturing and processing fiber optic cables, and more particularly to a fiber optic connector fiber stub remover and method. 
     The process of manufacturing the fiber optic light and signal transmitting element that carries the light and goes into fiber optic cable is well known and is largely automated. Extremely low attenuation rates allow optical cables to carry a high density of information with negligible error rates or the need for repeaters. For convenience of handling and ease of use, such as for connection to other devices and components, releasable connectors are positioned at the terminal ends of the optical fibers cables. The optical fibers pass through the connectors and are permanently affixed in place, e.g., by epoxy or other materials that pot the optical fibers in a plastic, composite, or Zirconia ferrule connector. In the final assembly, the terminal ends of the optical fibers will be finished to be flat, conical, or angled, but in all cases, free from imperfections so that when the fiber optic cables are connected to devices or other cables, the transmission of the optical signal will not be impeded. 
     During the manufacture of optical fiber connections, after the fiber is glued into the fiber optic connection, the fiber stub must be cleaved near the epoxy bead. This leaves fiber stubs that must then be removed before the optical fiber connections can be mounted to a polishing machine. Failure to do these two steps correctly can result in chips and cracks in the fiber, rendering them useless and in need of replacement. The position of the cut must be very precise and the cuts are never perfect and free from imperfections. Anything less near perfection is not good enough and therefore during the manufacturing process, after the optical fibers are cut, they must be further trimmed to be shorter and close to the bead of epoxy potted in the connector. If the optical fibers are too long when the polishing process begins, the optical fibers can easily bend and distort, preventing the ends from being processed as needed. 
     These steps noted above are very delicate, and there remains a substantially amount of handwork. Indeed, the process of manufacturing fiber optic cables involves numerous steps and remains labor intensive. The current industry practice in the manufacturer of fiber optic cables is to cut the optical fiber at a point relatively close to the point at which it protrudes from the connector and bead of epoxy potted in the plastic connector. This is typically done using a sharp knife, such as with a sapphire tip knife. Thereafter, a technician will take a small section of abrasive film, such as polishing or lapping film, bow it out towards the optical fiber, and gentle sand the optical fiber in a circular manner until the tip is very close to the bead of epoxy. In the industry, they refer to this process as fiber optic connector fiber stub removal. 
     At this point, the optical fiber cable is ready for polishing, and the technician will mount the optical fiber cable via its connector to a polishing machine. After polishing, then the ends of the optical fiber are inspected for quality control, and only those that pass the inspection are placed in use. 
     While there is automated equipment for polishing the ends of the fiber optic cable, to the inventor&#39;s knowledge, there are no automated devices or methods for fiber optic connector fiber stub removal. 
     BRIEF DESCRIPTION OF THE INVENTION 
     One objective of the present invention is to provide an automated device for removing fiber optic connector fiber stubs. 
     Another objective of the invention is to provide a method for removing fiber optic connector fiber stubs. 
     A further objective of the invention is to integrate this procedure into a polishing machine. 
     Other features and advantages of the embodiments of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of at least one of the possible embodiments of the invention. 
     The basic design of the fiber optic connector fiber stub remover device and method includes a platen with a countersunk well cutout section and a raised perimeter rim. Grinding paper is affixed, e.g., with contact adhesive, to the rim, thereby forming an air pocket between the grinding paper and a lower surface. This air pocket will provide some “give” as the fiber optic connector fiber stub is being ground off, with the air pocket helping to provide greater resistance the more the grinding paper is pushed down. If desired, in addition to the perimeter raised areas of the platen, a central raised area can be provided to support a central area of the grinding paper. 
     Initially, a very slow movement of the platen is used to start to remove the fiber stub. This speed can be increased over time by a ramp signal sent to the drive motor that moves the platen. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a side view of an exemplary fiber optic cable FC connector. 
         FIG. 1B  is a side view of the ferrule portion of the exemplary fiber optic cable FC connector of  FIG. 1A . 
         FIG. 2  is a side view of an exemplary embodiment of an automated device for removing fiber optic connector fiber stubs of the invention. 
         FIG. 3  is a bottom perspective view of the automated device for removing fiber optic connector fiber stubs of  FIG. 2 . 
         FIG. 4  is a top perspective view of the automated device for removing fiber optic connector fiber stubs of  FIG. 2 . 
         FIG. 5  is a top plane view of the automated device for removing fiber optic connector fiber stubs of  FIG. 2  without the weight in place. 
         FIG. 6  is a top plane view of the automated device for removing fiber optic connector fiber stubs of  FIG. 2  with the weight in place. 
         FIG. 7  is a top perspective view of an exemplary embodiment of a platen for use with a polishing machine which allows it to be used as a device for removing fiber optic connector fiber stubs. 
         FIG. 8  is a cutaway side view showing a polishing film attached to the platen of  FIG. 7  and mounted to a cam portion. 
         FIG. 9  is a top perspective view of an exemplary embodiment of a holding fixture for use with a polishing machine adapted for use with the platen of  FIG. 7 . 
         FIG. 10  is a side view showing the platen with polishing film and cam portion of  FIG. 8  with the holding fixture of  FIG. 9  holding fiber optic cables connected, all mounted to a conventional polishing machine. 
         FIG. 11  is a cross-sectional side view showing a weight used to hold fiber optic cables in place on the holding fixture to push them into contact with the polishing film on the platen. 
         FIG. 12  is a screen print showing a display of the automated device for removing fiber optic connector fiber stubs of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1A  is a side view of an exemplary prior art fiber optic cable FC connector  10 , and  FIG. 1B  is a side view of the ferrule portion  12  of the exemplary fiber optic cable FC connector of  FIG. 1A . The fiber optic cable  10  has a connector end  12 , a fiber optic ferrule  14 , an epoxy bead  16  that extends up from the end of the ferrule  14 , and the fiber stub  18 . It is this fiber stub  18  that must be shortened and brought down to the same level as the epoxy bead  16  before the manufacture of the fiber optic cable  10  can be completed by finely polishing the terminal end of the optical fiber. As noted above, in the past, the process of removing the fiber optic stub was done by hand, such as by a worker taking a section of bowed sandpaper and lightly sanding the fiber stub until it is brought down to the level of the epoxy bead  16 . 
       FIGS. 2-6 , and  11  illustrate an exemplary embodiment of an automated device for removing fiber optic connector fiber stubs of the invention and, which are further detailed in the following description. 
       FIG. 2  is a side view,  FIG. 3  is a bottom perspective view, and  FIG. 4  is a top perspective view of an exemplary embodiment of an automated device for removing fiber optic connector fiber stubs  100  of the invention.  FIG. 5  is a top plane view of the automated device for removing fiber optic connector fiber stubs of  FIG. 2  without the weight in place, and  FIG. 6  is a top plane view of the automated device for removing fiber optic connector fiber stubs of the invention with the weight in place. The device has a top plate  102  with a platen opening  104  formed therethrough. A motor  106  is connected to the underside of the top plate  102  by motor mount  108 . A cam  110  is mounted to a shaft (not shown) of the motor  106  by a shaft mount  112  and is rotated by the motor. The cam  110  has an outer perimeter  114 , and has a non-constant radius between the point at which the cam  110  it is mounted to the shaft mount  112  and to points on the outer perimeter  114  of the cam  110 . The motor  106  can be operated electrically, pneumatically, hydraulically, or by other modes of operation. 
     A generally circular platen  120  rides on top of the cam  110  and is rotated by the turning cam  110 . The platen  120  extends through the platen opening  104  in the top plate  102 . A fixture  122  for holding a plurality of the connector ends  12  of the fiber optic cable  10  being processed (see  FIGS. 2 ,  4 , and  6 ) floats on top of the platen  120  and a weight  124  sits on top of the fixture  122 . The weight  124  applies pressure to the connector end  12  on the fiber optic cable to force is lightly downwards into contact with a polishing film  140  positioned on the platen  120 , as shown in  FIGS. 8 ,  10  and  11  as will be discussed below. Although a weight  124  is shown as applying the biasing force, other devices can be used to create the biasing force, including springs that would bias the connector ends and their fiber stubs downwardly into contact with the polishing film. Although the term “polishing film” is used herein, this film can be lapping film. 
     Turning to  FIG. 7 , there is shown a top perspective view of an exemplary embodiment of a platen  220  for use with a polishing machine which allows the polishing machine to be used as a device for removing fiber optic connector fiber stubs. This generally rectangular platen  220  is similar to the generally circular platen  120  disclosed above, other than having a generally rectangular shape. However, other features are the same and the same reference numerals are used to describe both the generally circular platen  120  and the generally rectangular platen  220 . 
       FIG. 8  is a cutaway side view showing a polishing film  140  attached to the platen  120  of  FIGS. 3-6  and mounted to a cam portion  110 . However, other than the shape of the platen  120  being generally circular versus rectangular as the platen  220  of  FIG. 7 , the arrangements can be the same. The platen  120  have a perimeter rim  126  with a top edge  128 . An optional central standoff  130  is shown, and has a top surface  132 . The level of the top edges and top surface  128  and  132 , respectively, are preferably co-planar, and form a well  134  with a bottom  136 . The optional central standoff  130  extends from the bottom of the well  134 . The top edge and top surface  128  and  136 , respectively, provide a flat surface for connection with a polishing film  140 , which, for example, can be detachably attached to the top edge and top surface  128  and  132 , for example, by contact adhesive on the back of the polishing film  140 . However, other methods can be used to hold the polishing film  140  in place on the platen  120 . This same arrangement is provided with a rectangular platen  220 . When the polishing film  140  is adhered to the top edges  128  and  132  of the platen  120  and  220 , an air pocket  138  is created in the well  134 , with the polishing film  140  being suspended above the bottom  136  of the well  134 . This air pocket  138  will act as a shock absorber and allow slight flexing of the polishing film  140  as the fiber optic cable  10  being processed for pushed down into contact with the polishing film  140 , with the resistance to further flexing being controlled by the air pressure in the air pocket  138 , as will be discussed further below. As best shown in  FIG. 3 , the generally circular platen  120  is detachably mounted to the cam  110 . As shown in  FIGS. 3 and 8 , the shaft mount  112  provides for connection of the cam  110  to the motor  108 . The cam  110  has an outer perimeter  114 , and has a non-constant radius between the point at which the cam  110  it is mounted to the shaft mount  112  and to points on the outer perimeter  114 . 
     Turning back to  FIGS. 2-6 , a cam follower  150  with a follower arm  152  with a rider end  154  at a distal end  156  of follower arm  152 . The rider end  154  rides on the perimeter  114  of the cam  110 . A drive pin  158  extends upwardly from a proximal end  160  of the follower arm  152 , and the drive pin  158  extends upwardly through an elongate slot  162  formed in the top plate  102 . A keeper  164  guides the follower arm  152  and can comprise a member extending from a bottom of the top plate  102  with a through hole formed therein. An elastic member  166 , such as a spring, is used to ensure that the rider end  154  of the follower arm  152  rides on the outer perimeter  114  of the cam  110 . As the cam  110  turns, the follower arm  152  and its drive pin  158  will thus move longitudinally along the direction of the elongate slot  162 . The fixture  122  will preferably (see  FIG. 5 ) or the weight  124  sitting on the fixture (see  FIG. 6 ) will be connected to the drive pin  158  and will be moved relative to the rotating platen  120 . However, it is possible to connect the weight  124  sitting on the fixture to the drive pin  158  (not shown). Referring to  FIGS. 4-6 , which show the drive pin  158  connected to the fixture  122 . The fixture  122  has narrower extension  172 A with a first elongate slots  174 A, and an opposite wider extension that has two slots  174 B and  174 C formed therein, adjacent to sides  172 B and  172 C. Stationary guide pins  176 A-C extend upwardly from the top plate  102  and pass through elongate slots  174 A-C, respectively, and ensure that the fixture  122  moves laterally back and forth relative to the turning cam  110 . The weight  124  has connector apertures  180  formed therein, for holding the connector ends  12  of the fiber optic cable  10 . In  FIGS. 2 ,  4 , and  6  some of the aperture  180  are shown empty, and some are shown occupies with the connector ends  12  (without the rest of the optical fiber cable shown.) However, in operation of the automated device for removing fiber optic connector fiber stubs  100 , normally all of the apertures  180  would be holding connectors of the fiber optic cable  10  being assembled. 
       FIG. 9  is a top perspective view of an exemplary embodiment of a holding fixture  250  for use with the generally rectangular platen  220  of  FIG. 7 . The holding fixture  250  has a plurality of connector apertures  252  formed therethrough which are designed to snugly receive connectors  12  for the fiber optic cable  10  (e.g., such as being well-shaped) such that the epoxy bead  16  that extends up from the top of the ferrule  14  and the fiber stub  18  (see  FIG. 1B ) is positioned below a bottom surface of the holding fixture  250 , where the epoxy bead and fiber stubs will be brought into contact with a polishing film that will be placed on the platen  220 , as shown in  FIG. 10 . 
       FIG. 10  is a cross-sectional side view of selective portions of a convention polishing machine with the platen of  FIG. 7  and holding fixture  250  of  FIG. 7  connected thereto to allow the convention polishing machine to be used as automated device for removing fiber optic connector fiber stubs.  FIG. 10  shows the connector ends  12  of fiber optic cables connected to the holding fixture  250 . The ferrule  14  can be see extending through the bottom of the holding fixture  250 . Stationary guide pins  376 A and  376 C ensure that the holding fixture  250  moved longitudinally in response to the motion created by a rider end  354  of a follower arm  352  riding along the perimeter rim  114  of the cam  110 , which elastic member  366  biases into contact with the perimeter rim  114  of the cam  110 . A motor  306  and its motor mount  308  are shown mounted below the top plate  302 . A drive pin  358  transfers the motion of the moving follower arm  352  to the fixture  250 . The motion set up between the connector ends  12  and the platen  250  can preferably be and orbital motion or a generally figure eight motion. 
       FIG. 11  is a detail view of part of the automated device for removing fiber optic connector fiber stubs  100  showing the weight  124  used to hold connector ends  12  of fiber optic cables in place on the holding fixture  120  to push them so that their fiber stub  18  and epoxy bead  16  come into contact with the polishing film  140  positioned on the platen  120 . During operation of the device  100 , the platen  120  will spin and the fixture  120  will moved from side to side carrying the fiber optic cables&#39; connector ends  12  to lightly sand away at the fiber stub  18  and epoxy bead  16  so that the hand labor required to trim the fiber stub  18  can be eliminated. 
     In prior processing machinery, such as fiber optic cable end polishing machines, each individual fiber optic cable  10  is mounted by their connector ends  12  to independently movable carriages, so that each fiber optic cable  10  will move independently relative to polishing film, which is typically mounted to a flat plate or with a thin layer of resilient foam material. Such prior art designs are more complex, and have more moving parts that are subject to malfunction, compared to the current device, which relies of the airspace between the platen and the polishing film  140  mounted to the top edge  128  and upper surface  132  of the perimeter rim  126  and optional central standoff  130  thereof to provide for flexing of the polishing film to provide cushioning during the process of trimming the fiber stub  18  to thereby avoid damage yet result in efficient trimming of the fiber stub  18 . 
     In a method of the invention, one or more fiber optic cables having connector ends with ferrules, from which extend fiber stub, are engaged with a fixture such that the fiber stubs extend below a lower surface of the fixture. The fixture is located over a platen with a polishing film defining an air pocket, as described above. A bias, such as a weight, is placed around the connector ends of the fiber optic cables so that the connectors in the fixture and will be pushed down so that the fiber stubs contact the polishing film. The platen is moved relative to the fixture and the connectors of the fiber optic cables so that the fiber stubs will be trimmed off by a polishing contact with the moving platen with polishing film. The platen is preferably mounted to a shaft having a cam and the shaft is rotated by a motor to rotate the platen. A follower arm riding on the cam is connected to the fixture to establish simultaneous lateral movement of the fixture relative to the platen as it is rotated. The method includes ramping up a speed of movement of the platen over a ramp up time from no movement or a slow speed, to a final higher speed in order to gradually begin to remove the fiber stubs without causing damage, and then maintaining the final higher speed for a desired amount of time to complete the fiber stub removal. The movement of the fiber optic cables relative to the platen will preferably be an orbital motion or a figure eight motion. 
       FIG. 12  is an exemplary screen print  300  showing an electronic screen display of the automated device for removing fiber optic connector fiber stubs of the invention. ASR  302  stands for “Automatic Stub Removal”. Time remaining  304  is the total time remaining to complete the process, and is displayed in seconds  306 . Clicking on “Start”  308  initiates or continues the processing, and Run time  310  is the total run time of the process. A “Stop” button  312  can be selected to discontinue to processing. Ramp time  214  is the time it takes the platen rotation speed to get up to a desired speed, and is measured in seconds. The Exit button  316  will stop the process entirely and reset everything. The Max speed=RPM (revolutions per second), is the maximum speed at which the platen will rotate. The automated device for removing fiber optic connector fiber stubs  100  will start out at a slow speed wherein the platen is rotated slowly and the fixture is likewise moved slowly across the polishing film so that the delicate fiber stub  18  is not damaged. As the fiber stub  18  is gently abraded by the polishing film, the speed will ramp up to more quickly complete the process. 
     The exemplary screen print  300  is just one example of the information and manner in which it is displayed. Other possibilities can be followed. 
     After the fiber stubs  18  of the fiber optic cables  10  are sufficiently trimmed, the fixture  122  holding the exemplary fiber optic cables  10  by their connector ends  12  can be moved over to a polishing machine without need to remove the fiber optic cables  10  from the fixture  122 , further saving time and labor. 
     Those having ordinary skill in the art may be able to make alterations and modifications in the present invention without departing from its spirit and scope. Therefore, it must be understood that the illustrated embodiments have been set forth only for the purposes of example and they should not be taken as limiting the invention as defined in the following. 
     The invention in its various embodiments can involve a service provided by various service providers using various methods including the software and hardware infrastructure necessary to support the various embodiments.