BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective and exploded perspective view of a conventional connector.
FIG. 2 is a perspective view of one embodiment of the connector assembly of the present invention.
FIG. 3 is a cut-away perspective view of the connector assembly of FIG. 2, highlighting the use of a glue body that is configured to retain both a drop cable having one or more strength members and a connector sub-assembly.
FIG. 4 is another cut-away perspective view of the connector assembly of FIG. 2, highlighting the use of a glue body that is configured to retain both a drop cable having one or more strength members and a connector sub-assembly.
FIG. 5 is an isolated perspective view of the assembled glue body and connector sub-assembly of FIGS. 3 and 4.
FIG. 6 is an isolated perspective view of the glue body of FIGS. 3-5.
FIG. 7 is another isolated perspective view of the glue body of FIGS. 3-5, highlighting the joining of a substantially flat drop cable incorporating an optical fiber and a pair of GRP strength members with the glue body.
FIG. 8 is an isolated perspective view of an end cap used in conjunction with the connector assembly of FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, like reference numbers will be used to refer to like components or parts.
Referring to FIG. 2, the connector assembly 40, also referred to herein as a “plug”, of the present invention includes a plug housing 42 that contains a connector sub-assembly 44 (i.e., a pre-assembled ferrule holder module), the connector sub-assembly 44 holding a ferrule 46. The connector sub-assembly 44 and ferrule 46 are accessible through one open end of the plug housing 42, such that the ferrule can be optically connected to the ferrule of a receptacle or another connector assembly, or plug. The shrouding fingers 48 of the connector assembly 40 are reduced in length as compared to the conventional connector 10 (FIG. 1) in order to allow two connector assemblies to better mate with one another, among other things. Any reduced protection that results is compensated for by increased flexibility in situations requiring a more protruding ferrule 46. The more protruding ferrule 46 also allows for more efficient pre-assembly and termination, including polishing, etc. The keyed configurations of the inner assembly and plug housing 42 of the connector assembly 40 require that the connector assembly 40 be assembled in one specific orientation, as described in greater detail below. This addresses the unresolved need for an alternative retention method that does not allow multiple ways (i.e., two 180-degree opposing ways) to assemble the connector components, thereby eliminating the requirement for fixturing and verification by an operator in order to make sure that the connector sub-assembly 44 is oriented properly. The other end of the plug housing 42 is more open as compared to the conventional connector 10. This fact, and the configuration of the end cap 50 used, described in greater detail below, allow for relatively free flexural movement of the plug housing 42 relative to a substantially flat drop cable 52 that incorporates one or more GRP strength members 54 (FIGS. 3, 4, and 7) or the like, for example. The one or more silicone O-rings 28 (FIG. 1) of the conventional Optitap connector 10 may be replaced with a single integrally formed and overmolded O-ring 56 that is disposed within a recessed channel 58 that is manufactured into the exterior surface of the plug housing 42. Optionally, the exterior surface of the plug housing 42 includes a number of convenient gripping surfaces.
Referring to FIG. 3, internally, the connector assembly 40 includes a retention body 60, or glue body, having a pair of snap hooks 62 configured to engage a pair of snap hook recesses 64 manufactured into opposing sides of the connector sub-assembly 44, the snap hooks 62 retaining the connector sub-assembly 44 against the glue body 60 once it is “snapped” into place. These snap hooks 62 each comprise a protruding “finger” member having a “hooked” end. Because the finger members have a degree of flexibility, they are deflected out of place or bent as the connector sub assembly 44 is pressed between them and “snap” back into place when the hooked ends of the finger members engage the snap hook recesses 64. Once the plug housing 42 is secured over the retention body and snap hooks, an interior surface of the plug housing 42 may contact the exterior surface of the snap hooks 62, maintaining the snap hooks 62 within the snap hook recesses 64. Advantageously, the snap hooks 62 or another sub-assembly retention feature allow the connector sub-assembly 44 to rotate slightly (± about 5 degrees maximum) about the axis of the glue body 60 and connector assembly 40, as the snap hook recesses 64 are somewhat oversized with respect to the snap hooks 62. The connector parts will self-align below about 45 degrees if the proper chamfer and lead-in detail exists, thus the sub-assembly retention feature allows the connector sub-assembly 44 to rotate less than about 45 degrees. This inherent radial float reduces the stringency of the manufacturing tolerances involved. This is especially important in an in-line application, where two connector assemblies are relatively rigidly aligned with respect to one another in order to meet mechanical performance requirements. In such applications, an alignment sleeve disposed between the connector assemblies is often not capable of adequately adjusting to both connector assemblies, which can have contrary orientations. The shaft 25 (FIG. 1) of the connector sub-assembly 44 is preferably disposed and held within a bore 66 (FIG. 6) manufactured into the end of the glue body 60 having the snap hooks 62. This end also includes a pair of alignment blocks 68 that are designed to ensure the proper positioning of the connector sub-assembly 44 on the face of the glue body 60.
Referring to FIGS. 4 and 5, the glue body 60 engages the plug housing 42 (FIG. 4) by means of one or more recesses 70 manufactured into the exterior surface of the glue body 60 and one or more corresponding protrusions 72 (FIG. 4) manufactured into the interior surface of the plug housing 42. Accordingly, the glue body 60 is “snapped” into place within the interior of the plug housing 42. Again, the materials chosen facilitate this and either or both of the recesses 70 or protrusions 72 can have complimentary angled surfaces. Advantageously, this mechanical retention of the glue body 60 within the interior of the plug housing 42 alleviates the problem of endface position variance due to heat shrink pistoning. Importantly, the exterior surface of the glue body 60 and the interior surface of the plug housing 42 also include corresponding flattened and raised surfaces. Thus, the keyed configurations of the glue body 60 and plug housing 42 of the connector assembly 40 (FIG. 4) require that the connector assembly 40 be assembled in one specific orientation. Again, this addresses the unresolved need for an alternative retention method that does not allow multiple ways (i.e., two 180-degree opposing ways) to assemble the connector components, thereby eliminating the requirement for fixturing and verification by an operator in order to make sure that the connector sub-assembly 44 is oriented properly. The geometries involved rely on material flexibility and utilize minor localized interferences between the semi-rigid bodies involved to determine molding tolerances, while maintaining mechanical integrity.
Referring to FIG. 6, the glue body 60 includes a relatively larger diameter portion 74 and a relatively smaller diameter portion 76, the larger diameter portion 74 located proximal to the end of the glue body 60 having the snap hooks 62 and the smaller diameter portion 76 located distal to the end of the glue body 60 having the snap hooks 62. When the glue body 60 is inserted into the plug housing 42, this larger diameter portion 74 acts as a natural stop as it contacts a shelf 78 manufactured into the interior surface of the plug housing 42 (see FIG. 4). As described above, the shaft 25 (FIG. 1) of the connector sub-assembly 44 (FIGS. 2-5) is preferably disposed and held within the bore 66 manufactured into the end of the glue body 60 having the snap hooks 62. This end also includes the pair of alignment blocks 68 that are designed to ensure the proper positioning of the connector sub-assembly 44 on the face of the glue body 60 in conjunction with the snap hooks 62.
In an alternative embodiment, the shaft 25 of the connector sub-assembly 44 is disposed and held between the two halves 14a,14b (FIG. 1) of the former crimp body 14 (FIG. 1), which is now eliminated. These are, in turn, disposed within the bore 66 manufactured into the end of the glue body 60 having the snap hooks 62. As above, this keeps the connector sub-assembly 44 centered with respect to the glue body 60 and the plug housing 42. In another alternative embodiment, the two halves 14a,14b of the former crimp body 14 are combined into a single crimp retainer (not shown) which is disposed within the bore 66 manufactured into the end of the glue body 60 having the snap hooks 62. Again, this keeps the connector sub-assembly 44 centered with respect to the glue body 60 and the plug housing 42.
Referring to FIG. 7, the glue body 60 also includes a central channel 80 positioned to receive at least one optical fiber 82 of the drop cable 52 and a pair of edge channels 84 positioned to receive GRP strength members 54 or other strength members of the drop cable 52. The optical fiber 82 (which typically has a diameter of about 250 μm) and the pair of GRP strength members 54 are encased within a drop cable sheath 86, as is well known to those of ordinary skill in the art. Although GRP strength members 54 are illustrated and described herein, the drop cable 52 can include other kinds of strength members as well, or as an alternative. Any such strength members can be accommodated by one or more channels manufactured into the glue body 60. Preferably, the pair of GRP strength members 54 protrude between about 10 mm and about 20 mm (and more preferably, about 17 mm) into the pair of edge channels 84 and the edge channels 84 are filled with an adhesive that serves to bond the drop cable 52 to the glue body 60. The adhesive can be a visible light curable epoxy, or an ultraviolet (UV) light or heat curable glue. All material choices depend upon the pull strength, temperature exposure range, and chemical resistance desired. In the case that a visible light curable epoxy is used, the glue body 60 is preferably substantially transparent such that visible light can reach and cure the epoxy. For example, a natural poly ether imide can be used, also providing a relatively high temperature resistance. This substantially transparent material allows for visual feedback during the adhesive filling and optical fiber routing processes. Advantageously, the pair of edge channels 84 separate the adhesive from the central channel 80 and the optical fiber 82. Because the edge channels 84 are sealed, material is prevented from flowing into the connector assembly 40 (FIGS. 2-4) internals during assembly. The connector assembly 40 of the present invention readily meets about the 100 lbf pull strength requirement desired, due to the use of the glue body 60 and the adhesive. During assembly, preferably, the drop cable 52 is secured to the glue body 60 first, and then the connector sub-assembly 44 (FIGS. 2-5) is attached to the glue body 60.
In an alternative embodiment, the pair of edge channels 84 are configured to accept a pair of wedge-type clamps which are held in place by a pair of uncrimped bands. These wedge-type clamps and uncrimped bands are subsequently fixed onto the GRP strength members 54 by crimping, thereby securing the drop cable 52 to the glue body 60. This represents a non-adhesive solution.
Referring to FIG. 8, the end cap 50 described above includes an insertion end 88 that is configured to be inserted snugly into the “back” end of the plug housing 42 (FIGS. 2 and 3). The end cap 50 also includes a tapering end 90 that is manufactured with a slot opening 92 that is configured to receive the substantially flat drop cable 52 (FIG. 7), which passes through the end cap 50 and into the plug housing 42.
As described above, the retention body 60 of the present invention is coupled to the connector sub-assembly 44 by one or more coupling features, such as the retention snap hooks 62. In conventional connector assemblies, optical fibers and/or strength member movement over time may cause the connector assembly, including the ferrule, to protrude or push forward relative to the connector outer housing or plug shroud, thus resulting in a defective drop cable incapable of proper interconnection. Stops positioned about protrusion 72 may prevent the retention body 60, once snapped into place, from being removed through the front, or connective, end of the plug assembly. Thus, as the fibers or strength members push forward into the retention body 60, the retention body may be stopped from moving internally within the plug housing 42 beyond a predetermined point. By coupling the connector sub-assembly 44 to the retention body 60, the connector sub-assembly is then also prevented from protruding beyond a predetermined point, providing a drop cable capable of proper interconnection over time. In one embodiment, the plug housing 42, retention body 60 and their contact points are capable of withstanding forces up to about 50 lbs.
Although the present invention has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples can perform similar functions and/or achieve like results. For example, the mating of two connector assemblies could be achieved by providing a “female” version of the connector assembly (i.e., an outlet). The mating order would be plug-outlet-plug. All such equivalent embodiments and examples are within the spirit and scope of the present invention and are intended to be covered by the following claims.
Patent Application
20080044137
