Patent Publication Number: US-2021181433-A1

Title: Cover for a fiber optic ferrule and ferrule push

Description:
REFERENCE TO RELATED CASE 
     This application claims priority under 35 U.S.C. § 119 (e) to U.S. provisional application No. 62/947,966 filed on Dec. 13, 2019, and is a continuation-in-part of U.S. patent Ser. No. 17/251,076, filed on Dec. 10, 2020, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     In a data center environment, the routing of optical fibers between data centers usually requires the connection of thousands of optical fibers to connect one data center building to another. Such connections involve manually fusion splicing several thousands of optical fibers. The splicing is usually the last job before the connection of the data centers is complete. However, manually splicing optical fibers is time consuming and expensive due to the labor costs and equipment needed for the job. Thus, this job becomes the bottleneck for bring the new data centers on-line. 
     A solution to avoiding the fusion-splicing includes using pre-terminated MT ferrules in a pulling grip (or “pulling sock”) attached to a jacketed cable between the two datacenter buildings. Such a pulling grip is known in the art. Depending on how many fibers per fiber optic ferrule are present, the number of fiber optic ferrules inside the pulling grip will vary. For example, one pulling grip may accommodate a total of 3456 fibers in 288 fiber optic ferrules (i.e., each ferrule having 12 fibers). These fiber optic ferrules are then pulled out of the pulling grip at a designated spot inside the second data center building. Subsequently, an MT-MPO adapter, such as the one shown in U.S. Pat. No. 7,296,935 owned by the Applicant, may be used to connect an MT ferrule directly to an MPO style connector. One concern with this approach is that a technician/user at the data center will need to handle a bare, terminated fiber optic ferrule. This increases the chances of damage to the ferrule, especially since there are hundreds of such fiber optic ferrules that need to be inserted into MT-MPO adapters. 
     While the pulling grip is fairly clean, the pre-terminated fiber optic ferrule inside the pulling grip may still be prone to debris or dust as many such parts coexist in a limited space. Debris or dust may then scratch the fibers on the end face and/or cause optical signal attenuation. Further, the pin clamp, the ferrule push and the ferrule may come apart during handling inside the pulling grip. This separation may damage the fiber optic ferrule, the ferrule push, or the optical fibers. 
     Thus, there is a need for a cover that keeps the faces of the pre-terminated fiber optic ferrule protected and covered within the pulling grip. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a cover for a fiber optic ferrule and ferrule push that includes a sleeve extending lengthwise between opposed front and rear ends, said sleeve defining a lengthwise-extending opening that opens through the rear end for receiving at least a portion of the fiber optic fiber optic ferrule and the ferrule push, the sleeve having a top side and an opposing bottom side, and two side walls extending between the top side and the bottom side and along at least a portion of the sleeve, a cutout in each of the two side walls, the cutout extending from the rear end towards the front end, and a receiver in the top side engaged with the ferrule push. 
     In some embodiments, the receiver is engaged with a key of the ferrule push. 
     In some embodiments, the receiver is a depression in a top surface within the lengthwise-extending opening. 
     In some embodiments, the receiver is a window extending through the top side. 
     In other embodiments, the receiver has a forward facing surface to engage a rearward facing surface on the key. 
     In some embodiments, the fiber optic ferrule and the ferrule push maintain a spatial relationship within the lengthwise-extending opening of the sleeve. 
     In yet another aspect, there is a fiber optic assembly that includes a ferrule push, a fiber optic ferrule positioned forward of the ferrule push within a pulling sock having a plurality of optical fibers supported by the ferrule, and a cover coupled to the fiber optic ferrule and the ferrule push and including a sleeve extending lengthwise between opposed front and rear ends, the sleeve defining a lengthwise-extending opening that opens through the rear end for receiving at least a portion of the fiber optic fiber optic ferrule and the ferrule push, the sleeve having a top side and an opposing bottom side, and two side walls extending between the top side and the bottom side and along at least a portion of the sleeve, wherein the fiber optic ferrule and the ferrule push are held together inside the pulling sock by the cover. 
     And in yet another aspect, there is a cover for a fiber optic ferrule and ferrule push that includes a sleeve extending lengthwise between opposed front and rear ends, said sleeve defining a lengthwise-extending opening that opens through the rear end for receiving at least a portion of the fiber optic fiber optic ferrule and the ferrule push, the sleeve having a top side and an opposing bottom side, and two side walls extending between the top side and the bottom side and along at least a portion of the sleeve, and a receiver in the top side to receive a projection associated with the ferrule push. 
     It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of a fiber optic assembly that includes a cover for a fiber optic ferrule and ferrule push according to the present invention; 
         FIG. 2  is an exploded view of the fiber optic assembly in  FIG. 1  with a representative fiber optic ferrule, ferrule push, guide pins and optical fibers; 
         FIG. 3  is an exploded, perspective view of the fiber optic ferrule and ferrule push in  FIG. 2 ; 
         FIG. 4  is a cross section of the fiber optic assembly in  FIG. 1 ; 
         FIG. 5  is a front left perspective view of the cover in  FIG. 1 ; 
         FIG. 6  is a rear left perspective view of the cover in  FIG. 1 ; 
         FIG. 7  is a top plan view of the fiber optic ferrule and ferrule push in  FIG. 2  in a spatial relationship as occurs in the cover; 
         FIG. 8  is a top plan view of the fiber optic assembly in  FIG. 1 ; 
         FIG. 9  is bottom left perspective view of the fiber optic assembly in  FIG. 1 ; 
         FIG. 10  is a cross section view of a second embodiment of fiber optic assembly according to the present invention; 
         FIG. 11  is a perspective view of another embodiment of a cover for a fiber optic ferrule and ferrule push according to the present invention; 
         FIG. 12  is a perspective view of yet another embodiment of a cover for a fiber optic ferrule and ferrule push according to the present invention 
         FIG. 13  is a top perspective view of the cover in  FIG. 12 ; 
         FIG. 14  is a perspective view of another embodiment of a cover for a fiber optic ferrule and ferrule push according to the present invention; 
         FIG. 15  is a side elevation view of the cover in  FIG. 14 ; and 
         FIG. 16  is a bottom view of the cover in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the present preferred embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
     Applicant notes that the term “front” or “forward” means that direction where the fiber optic connector and/or the ferrule would meet with another fiber optic connector or device, while the term “rear” or “rearward” is used to mean the direction from which the optical fibers enter into the fiber-optic ferrule, the fiber optic connector, or the ferrule push. Each of the components will therefore have a front and rear, and the two fronts or forward portions of the fiber optic ferrules would engage one another. Thus, in  FIG. 1 , the “front” of the fiber optic assembly is on the left side of  FIG. 1  and “forward” is to the left and out of the page. “Rearward” or “rear” is that part of the fiber optic connector or cover that is on the right side of the page and “rearward” and “backward” is toward the right and into the page. 
     One embodiment of a fiber optic assembly that includes a cover  10  for a fiber optic ferrule and ferrule push is illustrated in  FIGS. 1-2, 4-6, and 8-9 . The cover  10  has a sleeve  12  that extends lengthwise between a front end  14  and a rear end  16 . The sleeve  12  has a lengthwise-extending opening  18  that opens through the rear end  16  of the sleeve  12  for receiving at least a portion of a fiber optic ferrule and the ferrule push, described below. The combination of the cover  10  and the fiber optic ferrule and the ferrule push may be known as a fiber optic assembly  20 . The sleeve  12  has a top side  24  and an opposing bottom side  26 . Extending between the top side  24  and the opposing bottom side  26  are two side walls  28 , 30 . The side walls  28 , 30  extend along at least a portion of the sleeve  12 . While the side walls  28 ,  30  are illustrated as being the same length, they could have different lengths, may not reach all of the way to the front end  14  or the rear end  16 . As illustrated there may be a cutout  32  in each of the two side walls  28 ,  30 , the cutouts  32  preferably extending from the rear end  16  towards the front end  14 . 
     The lengthwise-extending opening  18  is formed and defined by the top side  24 , the opposing bottom side  26 , the two side walls  28 , 30 , and by internal surfaces  36  thereof. See  FIG. 6 . The top side  24  has a receiver  40  to engage a portion of a ferrule push  102 . As illustrated in  FIGS. 1-2, 4-6, and 8 , the receiver  40  is an opening through the top side  24 . However, in another embodiment, the receiver  40 ′ may be a depression in the top side  24 ′ from the lengthwise-extending opening  118 ′. See  FIG. 10 . The receiver  40  (and  40 ′) has a forward facing surface  42  at a rearward end of the receiver. The forward facing surface  42  partially defines the receiver  40  (window). Likewise, the receiver  40 ′ shown in  FIG. 10  has a passageway, instead of a window, that is shaped to accommodate a portion of the ferrule push  102 . 
     The fiber optic ferrule  104  may be an MT ferrule, which is generally known in the art. It may also take a number of other configurations, such as illustrated in  FIGS. 2 and 3 . However, the fiber optic ferrule  104  preferably has a main body  110  that includes a plurality of optical fiber support structures  112  (see also  FIG. 4 ), which may be a plurality of micro-holes, v-grooves, or the like. The optical fiber support structures  112  support and hold the optical fibers  114  inserted into the fiber optic ferrule  104 . The main body  110  extends between a front end  120  and a rear end  122 , the optical fibers  114  extending from a front face  124  of the front end  120  through a central opening in the main body  110  and exiting out the rear end  122 . The rear end  122  of the main body  110  also has a rear face  128 . The fiber optic ferrule  104  may also have guide pins  130  (see  FIG. 2 ) and/or a guide pin clamp or spacer  132  disposed at the rear end  122 . There may also be more than one central opening through the fiber optic ferrule  104 . For example, there may be two or more rows of optical fibers  114 , optical fiber support structures  112  in the fiber optic ferrule  104 . See  FIGS. 2 and 3 . 
     The fiber optic ferrule push  102  also has a main body  150  that extends between a front end  152  and a rear end  154 . The main body includes a central opening  156  that extends between the front end  152  and the rear end  154 . The central opening  156  also receives the optical fibers  114  that are disposed in the fiber optic ferrule  104 . The front end  152  of the main body  150  preferably has the same dimensions of the rear end  122  of the fiber optic ferrule  104 . However, those dimensions of the main body  150  may be different from the fiber optic ferrule  104  as well. Since the optical fibers  114  are already in a ribbonized form, a height of the central opening  156  through which the ribbonized optical fibers  114  pass is preferably less than a width of the ribbon (in a transverse direction), at least at the front end  152 , and possibly all throughout a length of the fiber optic ferrule push  114 . Such a height prevents the fiber optic ferrule push  102  from being rotated relative to the ribbonized optical fibers  114  and fiber optic ferrule  104 , for example, when inside a pulling grip, and even afterwards when the fiber optic ferrule  104  engages the fiber optic ferrule push  104 . Preferably, the fiber optic ferrule push  102  is generally longer than the fiber optic ferrule  104  (i.e., in a longitudinal direction parallel to the optical fibers  114 ). Alternatively, the fiber optic ferrule push  102  may be of similar length as the fiber optic ferrule  104 . Regardless of the length thereof, the fiber optic ferrule push  102  has substantially the same footprint as the fiber optic ferrule  104 . The term “footprint” as used in this disclosure refers to only height, only width, or both height and width of the component in question (e.g., fiber optic ferrule  104  and/or the fiber optic ferrule push  102 ) when viewed in a cross-sectional plane that is perpendicular to a longitudinal/lengthwise axis of the component. In some embodiments, the fiber optic ferrule push  102  (including a key  160 , projection(s)  180 , and a rear boss/flange on a side of the fiber optic ferrule push  102 ) may protrude no further than or only slightly further than the footprint defined by the fiber optic ferrule  104  (specifically a flange/shoulder thereof). The footprint may, for example, be less than  10 % larger than that defined by the fiber optic ferrule  104 . 
     The fiber optic ferrule push  102  includes a first alignment structure or projection  160  on a top surface  162  of the main body  150 . It may also be referred to as a “key” to one of ordinary skill in the art. The first alignment structure  160  is illustrated as a raised portion in the figures, but also take on other configurations. The key  160  may take any shape or location on the fiber optic ferrule push  102 . For example, the key  160  may also be on one of the side surfaces  166 , which are on opposing sides of the top surface  162 . 
     There may also be a window  168  extending through the top surface  162  and is in communication with the central opening  156  that forms a passageway for the optical fibers  114 . This window  168  allows for access and/or visual inspection by a user to the optical fibers  114 . 
     The fiber optic ferrule push  102  has at least one projection  180  or latch that extends from the main body  150  to engage a corresponding structure  182  in a housing  106  for the fiber optic ferrule  104  and the ferrule push  102 . Preferably, there are two such projections  180 , but only one may be necessary to retain the fiber optic ferrule push  102  within the housing. As illustrated in figures and perhaps best in  FIG. 7 , the projections  180  take the form of cantilevered arms, that include a front chamfered surface  184  and a rear facing flat surface  186  to engage the housing. 
     As illustrated in  FIGS. 2 and 7 , the ferrule push  102  has an alignment structure or key  160 . The key  160  has a rearward facing surface  170 . The cover  10  is made of a material that is somewhat flexible or bendable, at least at the rear end  116 . Accordingly, as the ferrule push  102  and the fiber optic ferrule  104  are inserted into the sleeve  12 , the key pushes against and bends the top side  24  and its internal surface  36 . Once the ferrule push  102  and the fiber optic ferrule  104  are disposed within the lengthwise-extending opening  18 , the key  160  will pop up and into the window  40 . The engagement of the rearward facing surface  170  with the forward facing surface  42  prevents the ferrule push  102  and the fiber optic ferrule  102  from exiting the cover  10 . If the ferrule push  102  is pulled on, those two surfaces will prevent the removal of the ferrule push  102 . The cover  10  is also configured so as to keep the ferrule push  102  and the fiber optic ferrule  104  in a constant spatial relationship as illustrated in  FIG. 7 . That is, the ferrule push  102  will engage the rear end of the fiber optic ferrule  104 . As such, when the fiber optic assembly  20  is disposed within the pulling grip, the ferrule push  102  and the fiber optic ferrule  102  will stay connected with one another. Accordingly, the fiber optic ferrule  102  and the ferrule push  104  are held together inside the pulling grip by the cover  10 . See, e.g.,  FIG. 4 . While the key  160  plays double duty as a key and as a projection that engages the receiver  40 , the key and the projection maybe two different elements and/or structures. 
     The lengthwise-extending opening  18  may be configured to match the structure of the ferrule push  102  and the fiber optic ferrule  104 . The front end  120  of the fiber optic ferrule may engage a corresponding structure in the lengthwise-extending opening  18  to provide a stop point for the ferrule push  102  and the fiber optic ferrule  104 . See again,  FIG. 4 . The cover  10  may also have openings at the front end  14  to receive the guide pins  130 . These structures will be positioned within the sleeve so that the key  160  will be disposed within the receiver  40  (or  40 ′) and its rearward facing surface  170  engages the forward facing surface  42 . To remove the ferrule push  102  and the fiber optic ferrule  104 , a lever or finger can pull up on the top side  24  to allow clearance of the sleeve  12  by the key  160 . The cover  10  may then be pulled forward and away from the ferrule push  104  and the fiber optic ferrule  102  outside the pulling sock. Subsequently, the cover  10  may be disposed or reused. 
     The cutouts  32  each receive one of the projections or latches  180  on the ferrule push  102 . The projections  180  extend outward of the sides of the ferrule push  102 . The cutouts  32  therefore allow for the sleeve  10  to be as narrow as possible and still not have to worry about the projections  180  engaging the sleeve  10 , thereby optimizing the space available inside the pulling sock for several such fiber optic assemblies  20 . 
       FIG. 11  illustrates another embodiment of a cover  210  for a fiber optic ferrule and ferrule push according to the present invention. The cover  210  is similar to the cover  10  and has the same general configuration and elements. One of the differences in cover  210  is that there are two receivers  40  and  240  to engage a portion of a ferrule push  102 , rather than just the one receiver  40  in the top side  224 . As illustrated in  FIG. 11 , there is a receiver  40  in the top side  224  and a second receiver  240  in the opposing bottom side  226 . As explained above, the two receivers  40  and  240  may be a depression in the top side from the lengthwise-extending opening. 
     Each of the receivers  40 ,  240  has a forward facing surface, elements  42  and  242 , respectively, at a rearward end of the receiver. The forward facing surfaces  42 , 242  partially define the receivers  40 , 240 . 
       FIGS. 12 and 13  illustrate yet another embodiment of a cover  310  for a fiber optic ferrule  104  and ferrule push  102  according to the present invention. In this embodiment, the cover  310  has a top side  324  and an opposing bottom side  326 . In this embodiment, the top side  324  and the bottom side  326  do not extend as far rearwardly as they do in the previous embodiments. Indeed, the top side  324  and the bottom side  326  stop prior to where the receivers were in those prior embodiments. In fact, there are no receivers in this embodiment, but rather cutouts as discussed below. The two side walls  328 , 330  extend between the top side  324  and the opposing bottom side  326  and rearwardly along at least a portion of the sleeve  312  and farther rearwardly than the top side  324  and the bottom side  326 . As illustrated, there is a cutout  332  in each of the two side walls  328 ,  330 , the cutouts  332  preferably take the form of a hole or opening that has a rearward portion  338  to enclose the cutouts  332 . The cutouts are to receive the projection  180  or latch that extends from the main body  150  of the ferrule push  102 . In this case, it is the projection  180  engaging the cutout  332  that retains the fiber optic ferrule push  102  and the fiber optic ferrule  104  in the cover  310 . 
       FIGS. 14-16  illustrate another embodiment of a cover  410  for a fiber optic ferrule  104  and ferrule push  102  according to the present invention. In this embodiment, the cover  410  has a top side  424  and a shortened opposing bottom side  426 . In this embodiment, the bottom side  426  does not extend as far rearwardly as does the top side  424  or as it does in the previous embodiments (except for cover  310 ). The bottom side  426  does extend far enough to prevent the end face of the fiber optic ferrule  104  from becoming contaminated, however. The two side walls  428 , 430  extend between the top side  424  and a least a portion of the bottom side  426 , but then the height of the side walls decreases the farther to rear of the cover  410 . The top side  424  does have a receiver  440 , which is illustrated as an opening through the top side  424 , or alternatively it may also be a depression such as receiver  40 ′. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.