Patent Publication Number: US-2023145020-A1

Title: Fiber Optic Connector Push-Pull Boot with Self-Locking Boot Latch

Description:
REFERENCE TO RELATED CASE 
     This application claims priority under 35 U.S.C. § 119 (e) to U.S. provisional application No. 63/276,826 filed on Nov. 8, 2021, and under 35 U.S.C. § 120 to U.S. Design Patent Application 29/814,639, filed on Nov. 8, 2021, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Many optical connectors have connector latches that attach the optical connector to an adapter. The connector latch mechanism may be actuated by a conventional release member. Typically, this release member is depressed to release the latching mechanism, and hence the optical connector, from the adapter. The release member may be depressed using the user&#39;s thumb or fingers, and/or using a push-pull stick attached to the release member. Examples of such conventional release members and legacy push-pull tab/stick techniques are shown in U.S. Pat. Nos. 9,958,621 and 10,712,512. However, push-pull sticks consume space and are not preferred in high density connector environments for various reasons. 
     To move away from the push-pull sticks, the optical connector industry is adopting various push-pull boots that allow the optical connector to be attached to or removed from the adapter. One such example push-pull boot (without the aforementioned release member) is disclosed in Applicant&#39;s U.S. Pat. No. 11,112,567. These push-pull boots are bendable and flexible in any direction away from the longitudinal axis. 
     Yet another type of push-pull boot that does away with the push-pull stick or tab is shown in Applicant&#39;s US Patent Publication No. 2021/0191053. However, this push-pull boot is detachable from the MPO connector and is intentionally designed to be so. 
     In some technical applications, there is a need to have push-pull boots that can be attached to the aforementioned release member. However, in those applications it is desirable to have the push-pull boot stay attached to the release member and not be detachable. In such cases, the push-pull boot needs to be able to withstand pulling forces by the user in order to release the optical connector from the adapter, but not completely detach from the optical connector. However, the flexible material of the push-pull boot may prevent the push-pull boot from staying attached to the release member. Accordingly, there is a need for a push-pull boot that provides for the benefits of a rigid push-pull stick without occupying as much space, but is also not detachable and does not increase the assembly part count like the push-pull stick. 
     SUMMARY OF THE INVENTION 
     According to one aspect, the present invention is directed to a fiber optic connector that includes a ferrule configured to support at least one optical fiber, a plug at least partially surrounding the ferrule, a connector latch attached to the plug to engage the fiber-optic connector with an adapter or with a receptacle, a connector body attached to the plug, a release member attached to the connector body and to the connector latch and having a boot latch opening at a rear end, a push-pull boot attached to the release member, and a boot latch attached to the push-pull boot and extending forward and away from the push-pull boot, the boot latch having a first side extension and a second side extension and a central head member connected to and at least partially disposed between the first side extension and the second side extension by at least one flexure member, wherein the boot latch is permanently disposed within the release member after the boot latch is inserted into the boot latch opening as the central head member engages each of the first side extension and the second side extension preventing removal of the boot latch from the release member when a push force or a pull force is applied to the push-pull boot. 
     In some embodiments, the fiber optic connector includes a connector body, a release member attached to the connector body and having a boot latch opening at a rear end, a push-pull boot attached to the release member, and a boot latch attached to the push-pull boot and extending forward and away from the push-pull boot, the boot latch having a first side extension and a second side extension and a central head member connected to and at least partially disposed between the first side extension and the second side extension by at least one flexure member, wherein the boot latch is permanently disposed within the release member after the boot latch is inserted into the boot latch opening as the central head member engages each of the first side extension and the second side extension preventing removal of the boot latch from the release member when push or pull forces are applied to the push-pull boot. 
     In some embodiments, the central head member is in a first position relative to the first side extension and the second side extension before the boot latch is inserted into the release member and the central head member is in a second position relative to the first side extension and the second side extension after the boot latch is inserted into the boot latch opening, the boot latch being retained in the release member as the central head member engages each of the first side extension and the second side extension preventing the boot latch from passing through the boot latch opening in the release member when push or pull forces are applied to the push-pull boot after the boot latch is inserted into the boot latch opening 
     In some embodiments, the release member has at least one rearward facing surface to engage the central head member when the boot latch is inserted into the release member a predetermined distance. 
     In some embodiments, the boot latch opening has a chamfered surface on each side thereof and the first side extension and the second side extension have a side ramp that engages a respective chamfered surface on the boot latch opening, causing the first side extension and the second side extension to move toward one another as the boot latch is inserted into the opening. 
     In some embodiments, the at least one rearward facing surface engages a shoulder on the central head member. 
     In some embodiments, the central head member has a recessed portion on opposing sides to receive an inward projection from the first side extension and the second side extension, respectively. 
     In some embodiments, the inward projection on each of the first side extension and the second side extension are disposed within the recessed portions thereby preventing the first side extension and the second side extension from moving toward each other when force is applied to the boot latch. 
     In yet another aspect, there is a push-pull boot for use with a fiber optic connector having at least one fiber optic ferrule to support at least one optical fiber, the push-pull boot that includes a main body having a front end and a back end and defining a longitudinal axis between the front end and the back end, and a boot latch attached to the main body adjacent the front end of the main body and extending substantially parallel to the longitudinal axis and away from the back end of the main body of the push-pull boot, wherein the boot latch includes a first side extension and a second side extension and a central head member positioned between the first side extension and the second side extension, and wherein the first side extension and the second side extension and the central head member are engaged with each other in a locked state, and wherein upon an application of a rearward force to the push-pull boot to detach the fiber-optic connector from an adapter or a receptacle, the push-pull boot remains in an attached state with the fiber-optic connector. 
     In some embodiments, the push-pull boot has more rigidity in a direction substantially parallel to the longitudinal axis but has lesser rigidity and is bendable in a direction away from the longitudinal axis. 
     In yet another aspect, there is a combination of a release member and a push-pull boot for a fiber-optic connector that includes a release member removably attachable to a connector body and to a connector latch of the fiber-optic connector, the release member having a boot latch opening, and a push pull boot attached to the release member and configured to support a fiber optic cable containing at least one optical fiber, the push-pull boot having a boot latch attached to a front portion of the push-pull boot and extending forwardly substantially parallel to a longitudinal axis of the push-pull boot, wherein the boot latch is remains engaged with the release member inside the boot latch opening of the release member when pull forces are applied to the push-pull boot to detach the fiber optic connector from an adapter or a receptacle. 
     And in yet another aspect, there is a duplex fiber optic connector that includes a pair of ferrules each configured to support an optical fiber, a pair of plugs at least partially surrounding each of respective ones of the pair of ferrules, a connector latch attached to each plug in the pair of plugs to engage the fiber-optic connector with an adapter, a connector body attached to the pair of plugs, a release member attached to the connector body and to the connector latch and having a boot latch opening at a rear end, a push-pull boot attached to the release member, and a boot latch attached to the push-pull boot and extending forward and away from the push-pull boot, the boot latch having a first side extension and a second side extension and a central head member connected to and at least partially disposed between the first side extension and the second side extension by at least one flexure member, wherein the central head member is in a first position relative to the first side extension and the second side extension before the boot latch is inserted into the release member and the central head member is in a second position relative to the first side extension and the second side extension after the boot latch is inserted into the boot latch opening, the boot latch being retained in the release member as the central head member engages each of the first side extension and the second side extension preventing the boot latch from passing through the boot latch opening in the release member when push or pull forces are applied to the push-pull boot after the boot latch is inserted into the boot latch opening substantially along a longitudinal axis. 
     And there is also a combination of a release member and a push-pull boot for a fiber-optic connector, that includes a release member removably attachable to a connector body and to a connector latch of the fiber-optic connector, the release member having a boot latch opening, and a push pull boot attached to the release member and configured to support a fiber optic cable containing at least one optical fiber, the push-pull boot having a boot latch attached to a front portion of the push-pull boot and extending forwardly substantially parallel to a longitudinal axis of the push-pull boot, wherein the boot latch is remains engaged with the release member inside the boot latch opening of the release member when pull forces are applied to the push-pull boot to detach the fiber optic connector from an adapter or a receptacle. 
     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 connector according to one embodiment of the present invention and an adapter into which the fiber optic connector can be inserted; 
         FIG.  2    is a perspective view the fiber optic connector inserted into the adapter illustrated in  FIG.  1   ; 
         FIG.  3    is an exploded, perspective view of the fiber optic connector and adapter in  FIG.  2   ; 
         FIG.  4    is front perspective view of the fiber optic connector in  FIG.  2   ; 
         FIG.  5    is a rear perspective view of a release member used on the fiber optic connector in  FIG.  2   ; 
         FIG.  6    is a perspective view of the release member and a push-pull boot of the fiber optic connector in  FIG.  2   ; 
         FIG.  7 A  is a top view of the front end of push-pull boot showing the boot latch and with the central head member of the boot latch in a first position relative to the side extensions of the boot latch; 
         FIG.  7 B  is a side perspective view of the boot latch on the front of the push-pull boot; 
         FIG.  7 C  is a perspective view from under the boot latch that is on the front end of the push-pull boot; 
         FIG.  7 D  is top view of the boot latch at the front end of the push-pull boot; 
         FIG.  7 E  is a top view of the boot latch inserted into the release member; 
         FIG.  8    is a cross sectional view of the release member along a horizontal showing the inside features of the release member; 
         FIG.  9    is top perspective view of a cross section with the top of the release member removed; 
         FIG.  10    is a perspective view of the boot latch inserted partially into the release member with the top of the release member removed to show the central head member of the boot latch in a first position relative to the side extensions; 
         FIG.  11    is a perspective view of the boot latch fully inserted into the release member with the top of the release member removed to show the central head member of the boot latch in a second position relative to the side extensions; 
         FIG.  12    is a perspective view of the boot latch inserted into the release member with the top of the release member removed to show the central head member of the boot latch in a second position relative to the side extensions and being permanently disposed within the release member; 
         FIG.  13    illustrates a second embodiment of a push-pull boot with a boot latch according to the present invention and the central head member is in a first position relative to the side extensions; 
         FIG.  14    illustrates the second embodiment of the boot latch in  FIG.  13    with the central head member in the second position; and 
         FIG.  15    illustrates a third embodiment of a push-pull boot with a boot latch according to the present invention and the central head member is in a first position relative to the side extensions. 
     
    
    
     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. 
     Illustrated in  FIGS.  1 - 3    is one embodiment of a fiber optic connector  100  according to the present invention, along with a representative adapter  102  into which the fiber optic connector  100  can be inserted. The adapter  102  may be inserted into a panel or other structure and still fall within the scope of the invention, or the adapter  102  may be another type of receptacle to receive the fiber optic connector  100  (e.g., a transceiver receptacle attached to a circuit board). The adapter  102  should also have at least the same number of openings as there are fiber optic connectors  100  to be inserted into the adapter/receptacle  102 . 
     Applicant notes that in this disclosure the term “front” or “forward” means that direction where the fiber optic connector and/or the ferrule(s) therein would meet with another fiber optic connector or device (e.g., adapter), while the term “rear” or “rearward” is used to mean the direction from which the optical fibers enter into the fiber-optic connector or the ferrule. Each of the components will therefore have a front and rear, and the two respective fronts or forward portions of the fiber optic ferrules would engage one another. Thus, in  FIG.  4   , the “front” of the fiber optic connector and the push-pull boot is on the left side and “forward” is to the left and out of the page. “Rearward” or “rear” is that part of the fiber optic connector or push-pull boot that is on the right side of the page and “rearward” and “backward” is toward the right and into the page. 
     The fiber optic connector  100  includes a number of components. Referring to  FIGS.  3  and  4    in particular, some of these components include at least one ferrule  104  configured to support at least one optical fiber  106  and at least one plug  108  at least partially surrounding the ferrule  104 . The illustrated fiber optic connector  100  has two of the ferrules  104  and plugs  108 , making it a duplex connector. However, the present invention may have more or fewer ferrules  104 /plugs  108  and still fall within the scope of the invention. For example there may be only one ferrule  104 /plug  108  or there may be four ferrules  104 /plugs  108 . It therefore follows that the adapter  102  would have a corresponding structure to receive the appropriate number of ferrules  104 /plugs  108 . Further, in an alternative embodiment, the ferrules  104  may not each have a separate respective plug  108 . Rather, the ferrules may be in a common housing surrounding the ferrules  104  with the end faces of the ferrules  104  exposed at the front. 
     The fiber optic connector  100  also includes a connector latch  110  attached to the plug  108  to engage the fiber optic connector  100  with the adapter or the receptacle  102  to retain the fiber optic connector  100  in the adapter  102  and keep the fiber optic connector  100  from falling out, while also allowing for mating with other fiber optic connectors  100 . There is also a connector body  112  attached to the plug  108 . The fiber optic connector  100  also includes a release member  114  that is attached to the connector body  112 . The release member  114  engages with the connector latch  110 . The release member  114  has a boot latch opening  118  at a rear end  120  thereto. The release member  114  attaches to a push-pull boot  122  as described herein below, the push-pull boot  122  has a boot latch  124  that is inserted into the boot latch opening  118  of the release member  114 . The boot latch  124  extending forward (toward the ferrules  104 ) and away from the push-pull boot  122 . As seen in  FIGS.  6  and  7 A -E, the boot latch  124  has a first side extension  126  and a second side extension  128  and a central head member  130  connected to and at least partially disposed between the first side extension  126  and the second side extension  128  by at least one flexure member  132 . As noted in more detail below, the flexure member  132  is a flexible member that is deformable and pliable so as to allow the central head member  130  to move relative to the first side extension  126  and the second side extension  128 . The first side extension  126  and the second side extension  128  are spaced apart from each other along a transverse direction, which is the same direction as the space between the exposed end-faces of the ferrules  104 . 
     As discussed in more detail below, when the boot latch  124  is inserted into the release member  114  through the boot latch opening  118 . The central head member  130  engages a surface within the release member  114 , the central head member  130  will be permanently disposed between the first side extension  126  and the second side extension  128 . By “permanently,” it is meant that the boot latch  124  will not be removable from the fiber optic connector  100 , and the release member  114  in particular, once in a fully assembled state with normal activities around the fiber optic connector  100 . Applying more pressure/force than is standard (e.g., more than 80N) may be able to break the boot latch  124  free. So too will excessively deforming the fiber optic connector  100  or any of its components. “Permanent” means that the boot latch  124 , and thus the push-pull boot  122 , is not intended removable once inserted unless components are broken, destroyed, or manipulated in a manner that is inconsistent with the typical handling of similar parts. Since the central head member  130  engages and locks with each of the first side extension  126  and the second side extension  128 , the first side extension  126  and the second side extension  128  are prevented from moving inward towards each other, and the boot latch  124  cannot be removed from the release member  114  when a push force or a pull force is applied to the push-pull boot  122 . 
     The release member  114  will be described in view of  FIGS.  5 - 6  and  8 - 9   . The release member  114  has a top member  140  and two sides  142 ,  144 . The two sides  142 ,  144  engage the connector body  112 . The top member  140  has openings  146  that accommodate a portion of the connector latch  110 . When the push-pull boot  122  is pulled backward and away from the fiber optic connector  100 , the release member  114  also moves backward thereby depressing the connector latches  110  and allowing the fiber optic connector  100  to be removed from the adapter  102 . The engagement of the release member  114  with the connector body  112  may be different from the way that is illustrated in the figures. However, the boot latch opening  118  and the release member  114  have features that work with the boot latch  124  to keep the boot latch  124  within the release member  114  after installation. In particular, there are rearward facing surfaces/walls  150 , a chamfered surface  152  at the boot latch opening  118 , and a forward facing surface  154  adjacent to the chamfered surface  152 . See  FIGS.  8  and  9   . The release member  114  has a base or floor  160  and a ceiling  162  on the underside of the top member  140  that partially define the boot latch opening  118  and keep the boot latch  124  within the release member  114 . Illustrated in  FIGS.  8  and  9   , the rearward facing surfaces/walls  150  function to engage the central head member  130 . As the boot latch  124  is inserted into the boot latch opening  118 , the central head member  130  passes between the two rearward facing surfaces/walls  150 , but shoulders  184  on the central head member  130  engage the two rearward facing surfaces/walls  150  and the central head member  130  moves rearwardly relative to the first side extension  126  and the second side extension  128 . See again  FIGS.  7 A- 7 E . 
     Focusing now on the push-pull boot  122 , the push-pull boot  122  has a main body  170  that has a front end  172  and a back end  174  and defines a longitudinal axis A between the front end  172  and the back end  174 . See, e.g.,  FIGS.  1 - 2 ,  4  and  6   . The push-pull boot  122  is attached to the release member  114 . The push-pull boot  122  also has the boot latch  124  attached to the main body  170  adjacent the front end  172  of the main body  170  and extending substantially parallel to the longitudinal axis A and away from the back end  174  of the main body  170  of the push-pull boot  122 . As illustrated, the front end  172  of the push-pull boot  122  has a solid tubular portion  176  and then a spine  178  with flexible members  180  extending toward the back end  174 . The push-pull boot  122  provides protection for the fiber optic cable  190  that further protects the optical fibers  106  that are terminated in the ferrules  104 . The push-pull boot  122  may have other configurations such as a smaller or non-existent solid tubular portion  176  or, alternatively a larger section thereof. The push-pull boot  122  provides more resistance (that is it is more rigid and stiff) in a direction parallel to the longitudinal axis A and is more pliable and flexible in any direction away that takes the back end  174  away from the longitudinal axis A. In fact, in one embodiment of the push-pull boot  122 , the pulling on the push-pull boot  122  (away from the front end  172 ) with a 3.6N force resulted in an elongation of 0.05 mm. Pushing down on the push-pull boot  122  with a 0.5N force resulted in a movement of 5.2 mm. Thus, the stiffness or rigidity along the longitudinal axis A is 72 N/mm while the stiffness away from the longitudinal axis 0.1 N/mm. The means that the stiffness along the longitudinal axis is  720  times more than away from the longitudinal axis. This feature of the push-pull boot  122  allows for the insertion into and removal of the fiber optic connector  100  from the adapter  102  without buckling or pinching the fiber optic cable  190 , while still protecting the rear ends of the fiber optic connectors  100  while inserted in the adapters  102 . 
       FIGS.  7 A- 7 E  illustrate one embodiment of the boot latch  124 . Since the boot latch  124  is attached at the front end  172  of the push-pull boot  122 , only a portion of the push-pull boot  122  is illustrated in these figures. Specifically, the boot latch  124  connects to the push-pull boot  122  at the solid tubular portion  176 . Again, the boot latch  124  has a first side extension  126  and a second side extension  128  and a central head member  130 . The central head member  130  has a flat front surface  182 , although it could take on any number of shapes. Other either side of the central head member  130  are shoulders  184 , which have a forward facing surface and preferably engage the rearward facing surfaces/walls  150  when the boot latch  124  is inserted into the release member  114 . Directly behind the shoulders  184  are recesses  186  that receive a complementary structure (inward projections  194 ) on each of the first side extension  126  and the second side extension  128 . The central head member  130  is attached to the first side extension  126  and the second side extension  128  by the flexure members  132 . As illustrated in an alternative embodiment of a boot latch  324  in the  FIG.  15   , the flexure members  332  may be attached to the first side extension  326  and the second side extension  328  in a different location from that shown in  FIGS.  7 A- 7 E . 
     Each of the first side extension  126  and the second side extension  128  have at the ends thereof a side ramped surface  188  on an outside portion. The ramped surfaces  188  are to engage the chamfered surface  152  at the boot latch opening  118 . As the boot latch  124  is inserted into the boot latch opening  118 , the ramped surfaces  188  engage the chamfered surfaces  152  and cause the first side extension  126  and the second side extension  128  to move toward each other to pass into the boot latch opening  118 . Since the central head member  130  is not between the first side extension  126  and the second side extension  128 , they can move toward one another to provide space for the boot latch  124  to pass easily. See  FIG.  7 E . The forward facing surface  154  adjacent to the chamfered surface  152  within the boot latch opening  118  gathers the rearward facing surface  192  that is on the outside of the first side extension  126  and the second side extension  128  rearwardly from the ramped surfaces  188 . Thus, as illustrated in  FIG.  7 E , the central head member  130 , which is positioned so that the shoulders  184  are ready to engage the rearward facing surfaces/walls  150 , is still in the first position and not between the first side extension  126  and the second side extension  128 . See also  FIG.  10   . 
     As best illustrated in  FIG.  7 A , the first side extension  126  and the second side extension  128  have an inward projection  194  that is disposed within the recesses  186  when the central head member  130  is in the second position (shown in  FIG.  12   ). As such,  FIGS.  7 A- 7 E  show the central head member  130  in a first position relative to the first side extension  126  and the second side extension  128 . As illustrated in  FIG.  11   , the boot latch  124  has been advanced within the boot latch opening  118 , and with the central head member  130  being held in place by the rearward facing surfaces/walls  150 , the inward projections  192  are disposed within the recesses  186 , preventing the first side extension  126  and the second side extension  128  from being able to move relative to one another. However, it should be noted that in  FIG.  10   , the rearward facing surface  192  is not contacting the forward facing surface  154  adjacent to the chamfered surface  152  within the boot latch opening  118 . However, they do make contact when the push-pull boot  122  is pulled rearwardly relative to the releasing member  114 . See  FIG.  12   . 
     Another embodiment of a boot latch  424  is illustrated in  FIGS.  13  and  14   . The only difference between boot latch  424  and boot latch  124  is the central head member  430  and flexure members  432  have a different shape. The central head member  430  is connected to the flexure members  432  through a common attachment member  434 , rather than directly. The central head member  430  is in the first position in  FIG.  13    and in the second position in  FIG.  14   . As seen in the figures, the boot latch  424  has a first side extension  426  and a second side extension  428  to which the flexure members  432  are connected. The central head member  430  is still positioned with the shoulders  484  against the rearward facing surfaces/walls  150  of the releasing member  114 , when in the first position of the central head member  430 . 
     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.