Patent Description:
The mechanical tolerances involved in terminating single mode optical fiber are much tighter than those for multimode optical fiber. Therefore, while it is quite common for multimode optical fiber to be terminated at the point of use, for example, at a user's premises or at an outside junction box, in most product applications, single mode optical fiber is not terminated in the field. When single mode fiber must be terminated in the field, then it can take a skilled technician between about <NUM> to <NUM> minutes to splice fibers together either by using a V-groove clamp or expensive fusion welding equipment.

Single mode fiber is therefore often provided in a range of different lengths, pre-terminated at both ends with a connector that is configured to be connected with an outer housing after the pre-terminated end is deployed to its desired location. The pre-terminated end and housing is then ready to plug into a matching receptacle.

One example of such a connector is an LC connector. The LC connector and adapters were originally developed by Lucent Technologies. The LC connector is a miniaturized version of the fiber optic SC (Subscriber Connector) connector, thus being also known as a small form factor connector. The LC connector looks somewhat similar to the SC connector but is about half the size with a <NUM> ferrule instead of a <NUM> ferrule. LC connectors are typically composed of a plastic housing with an RJ45 push-pull style clip.

Conventional optical fiber LC connectors comprise a rigid pushable structure to allow for limited movement of the connector parts while being pushed down stretches of a duct. However, some conventional fiber optic cables include more than one fiber. For example, some fiber optic cables include two, four, or more fibers.

Conventional optical fiber LC connectors and LC connector sub-assemblies are not necessarily designed to minimize a cross-sectional footprint and, therefore, it is difficult to push multiple preterminated fibers of a multi-fiber cable through a duct simultaneously.

A further example of cable assembly with a removable installation device routing a preterminated optical fiber drop cable from an outdoor terminal to an indoor wall outlet, is disclosed in <CIT>. Such assembly includes an optical fiber drop cable with a connector body at its end and a removable device attached to the cable's jacket, which allows for tool-less removal through tear tabs.

Therefore, it may be desirable to provide a deployment assembly for preterminated multi-fiber drop cables having a minimal cross-sectional footprint so that the multiple fibers can be easily and smoothly pushed, pulled, or blown through a duct. It may be desirable to provide an LC connector that is field installable on a fiber optic cable preterminated with an LC sub-assembly after the preterminated fiber optic cable is pushed, pulled, or blown through the duct.

It may be desirable to provide a deployment assembly configured to be coupled with a plurality of preterminated fiber optic cables and to provide a cross-sectional footprint that is smaller than a cross-sectional footprint of a fiber optic connector that is configured to be assembled with the preterminated fiber optic cable such that the plurality of fiber optic cables can be easily and smoothly pushed, pulled, or blown together through a duct having an inner diameter than is less than a footprint the fiber optic connector. It may be desirable to provide a fiber optic connector configured to be field assembled with the plurality of preterminated fiber optic cables after the plurality of fiber optic cables are pushed, pulled, or blown together through a duct and the deployment assembly is removed from the plurality of preterminated fiber optic cables.

A deployment assembly is disclosed in any one of claims <NUM>-<NUM>.

Embodiments of the invention will now be further described, by way of example only, and with reference to the accompanying drawings, in which:.

<FIG> illustrate an exemplary deployment assembly <NUM> for pushing, pulling, and/or blowing multiple preterminated fiber optic cables of a multi fiber cable <NUM> through a duct. In the illustrated embodiment, the multi fiber cable <NUM> includes four fiber optic cables <NUM>. Of course, in various embodiments, the multi fiber cable <NUM> may include more or less than four fiber optic cables. Each of the four fiber optic cables <NUM> is terminated with a ferrule assembly <NUM>, for example, an LC ferrule assembly. Thus, in such an embodiment, the preterminated multi fiber cable <NUM> may be referred to as an LC quattro.

As best shown in <FIG>, <FIG>, and <FIG>, the ferrule assembly <NUM> includes a ferrule holder <NUM> having an outer sleeve portion <NUM> and an inner sleeve portion <NUM>. Referring to <FIG>, the inner sleeve portion <NUM> is configured to be received in the outer sleeve portion <NUM>. The inner sleeve portion <NUM> includes a flanged portion <NUM>' at its forward end, and the outer sleeve portion <NUM> includes a stepped portion <NUM>' configured to define a shoulder having a forward facing surface <NUM>". The inner sleeve portion <NUM> is configured to be received in a forward end of the outer sleeve portion <NUM> and can be slid axially through the outer sleeve portion <NUM> to a position where the flanged portion <NUM>' engages the stepped portion <NUM>'.

A ferrule <NUM> is configured to be seated in an outer sleeve portion of the outer sleeve portion <NUM> of the ferrule holder <NUM> forward of the flanged portion <NUM>' of the inner sleeve portion. A spring <NUM> is configured to be seated in an annular channel <NUM> at rear portion of the outer sleeve portion <NUM> between an inner wall <NUM> of the outer sleeve portion <NUM> of the ferrule holder <NUM> and an outer wall of the inner sleeve portion, as best shown in <FIG>. An outer surface of the ferrule holder <NUM> includes two flatted regions <NUM> on opposite sides of the ferrule holder <NUM>. The ferrule <NUM> may be a cylindrical ceramic ferrule. The ferrule assembly <NUM> preterminates an end <NUM> of a fiber optic cable <NUM>, which includes a buffer tube <NUM> that surrounds and protects a fiber <NUM>. A dust cap <NUM> is configured to be received over and cover the ferrule <NUM> to protect the ferrule <NUM> and the fiber <NUM> in the ferrule <NUM>. The dust cap <NUM> includes an attachment structure <NUM>, which is described in more detail below.

Referring again to <FIG> and <FIG>, the deployment assembly <NUM> includes a sleeve <NUM>, for example, a crimp sleeve, having a through bore <NUM>. The sleeve <NUM> is sized such that the ferrule assemblies <NUM> of the preterminated fiber optic cables <NUM> and the multi fiber cable <NUM> can be received in the sleeve <NUM> and the sleeve <NUM> can be crimped onto an end of the multi fiber cable <NUM>. For example, the preterminated fiber optic cables <NUM> can be inserted, one at a time, from a rear end of the sleeve <NUM> and out of a forward end of the sleeve <NUM> until the multi fiber cable <NUM> is at a position in the sleeve <NUM> such that the sleeve <NUM> can be crimped thereon.

The deployment assembly <NUM> also includes a rod <NUM> such as, for example, a glass reinforced plastic (GRP) rod. The rod <NUM> may be coupled with a forward end of the sleeve <NUM>, for example, the rod <NUM> may be potted inside of the sleeve <NUM>. In some aspects, the rod <NUM> may include a pulling hook <NUM> at a first end <NUM> of the rod <NUM>. The pulling hook <NUM> may include a through hole <NUM> extending in a transverse direction relative to a longitudinal dimension of the rod <NUM>.

With the dust caps <NUM> on the ferrules <NUM>, the attachment structures <NUM> are configured to couple the dust caps <NUM> and thus the preterminated ends <NUM> of the fiber optic cables <NUM> to the rod <NUM>. For example, the attachment structure <NUM> may include a C-shaped projection <NUM> configured to snap onto the rod <NUM>. As would be understood by persons skilled in the art, the C-shaped projection <NUM> has an opening <NUM> slightly smaller than an outside diameter of the rod <NUM> and is sufficiently flexible to expand to receive the rod <NUM> and then return toward its non-expanded configuration after it is snapped onto the rod <NUM>.

In some aspects, the deployment assembly <NUM> may include a protective sleeve <NUM> that is configured to surround the sleeve <NUM>, the buffer tubes <NUM>, the ferrule assemblies <NUM> of the preterminated fiber optic cables <NUM>, and/or the dust caps <NUM>. As shown in <FIG>, the sleeve <NUM> may surround at least a portion of the sleeve <NUM> and may extend from the sleeve <NUM> to a location beyond the forwardmost dust cap <NUM> and attachment structure <NUM> such that the protective sleeve is configured to protect the buffer tubes <NUM>, the ferrule assemblies <NUM> of the preterminated fiber optic cables <NUM>, the dust caps <NUM>, and the attachment structure <NUM> as the deployment assembly <NUM> is pulled, pushed, or blown through a duct. In some aspects, the protective sleeve <NUM> may comprise, for example, a Polytetrafluoroethylene (PTFE) protective sleeve, which may be configured to reduce friction between the duct and the deployment assembly <NUM> during the pulling, pushing, or blowing.

The preterminated ends <NUM> of the fiber optic cables <NUM> of the multi fiber cable <NUM> are configured to be fed through the sleeve <NUM>. The sleeve <NUM> is configured to be the slid over an end <NUM> of the multi fiber cable <NUM>, and an inner sleeve portion <NUM> of the sleeve <NUM> is configured to be crimped onto the end <NUM> of the multi fiber cable <NUM>. A second end <NUM> of the rod <NUM> is configured to be inserted into an outer sleeve portion <NUM> of the sleeve <NUM>, and the fiber optic cables <NUM> and the rod <NUM> may be potted in the outer sleeve portion <NUM> of the sleeve <NUM>.

In some aspects, the preterminated ends <NUM> of the fiber optic cables <NUM> of the multi fiber cable <NUM> may be fed through the sleeve <NUM> with the dust caps <NUM> on the ferrules <NUM>. In some aspects, the preterminated ends <NUM> of the fiber optic cables <NUM> of the multi fiber cable <NUM> may be fed through the sleeve <NUM> without the dust caps <NUM>, and the dust caps <NUM> are slid on the ferrules <NUM> after the fiber optic cables <NUM> are fed through the sleeve <NUM>.

As illustrated, the rod <NUM> has a length that is greater than a length of the longest buffer tube <NUM> that extends from the multi fiber cable <NUM>. Lengths of the buffer tubes <NUM> of the fiber optic cables <NUM> that extend from the multi fiber cable <NUM> are different so that the attachment structures <NUM> can be spaced along a length of the rod <NUM> without bending or buckling the fiber optic cables <NUM> beyond a minimum bend radius. It should be appreciated that the rod <NUM> is configured to be sufficiently rigid to be pushed, pulled, or blown through a duct and sufficiently flexible to navigate turns in the duct.

In a case where the deployment assembly <NUM> is to be pulled through a duct, an installer can insert a hook or any other coupling arrangement (not shown) through the through hole <NUM> of the pulling hook <NUM> at the first end <NUM> of the rod <NUM>. The hook or other coupling arrangement is coupled with a pulling mechanism, which can be used to pull the deployment assembly <NUM>, and thus the fiber optic cables <NUM> through the duct. Alternatively, the deployment assembly <NUM> may be pushed or blow through the duct, as would be understood by persons skilled in the art.

After the fiber optic cables <NUM> are deployed to a desired location, the rod <NUM> can be removed from the sleeve <NUM>. In some embodiments, the sleeve <NUM> may also be removed from the multi fiber cable <NUM> and slid over the preterminated ends <NUM> of the fiber optic cables <NUM> with or without the dust caps <NUM> on the ferrules <NUM>.

Referring now to <FIG>, an exemplary field assembled fiber optic connector <NUM> is illustrated and described. Once the fiber optic cables <NUM> are deployed to a desired location, each of the preterminated ends <NUM> of the fiber optic cables <NUM> can be coupled with a body <NUM>, a housing <NUM>, and a boot <NUM> to form the connector <NUM>, for example, an LC connector.

As shown in <FIG> and <FIG>, the body <NUM> includes a substantially cylindrical forward end portion <NUM>, a rearward end portion <NUM>, a substantially square middle portion <NUM> between the forward end portion <NUM> and the rearward end portion <NUM>, and a radial slot <NUM> that extends from a top <NUM> of the body <NUM> to a center <NUM> of the body along the full length of the body <NUM> from the forward end portion <NUM> to the rearward end portion <NUM>. The radial slot <NUM> is sized to receive the buffer tube <NUM> and permit the buffer tube <NUM> to be disposed at the center <NUM> of the body <NUM>. The forward end portion <NUM> includes a bore <NUM> having a circular cross section with a diameter that is greater than a dimension of the radial slot <NUM> in a direction perpendicular to the radial direction from the top <NUM> to the center <NUM> of the body <NUM> and perpendicular to the longitudinal dimension of the body <NUM>. The bore <NUM> includes a first portion <NUM>' sized to slidingly receive the spring <NUM> and the rear stem portion <NUM> surrounded by the spring <NUM> and a second portion <NUM>" having a smaller inside diameter than the first portion <NUM>' so as to define a forward facing shoulder 176a. A rear end of the spring <NUM> is configured to engage the shoulder 176a, as shown in <FIG>. The bore <NUM> may include a third portion <NUM>'" having a larger inside diameter than the first portion <NUM>' and being configured to guide the spring <NUM> into the first portion <NUM>' of the bore <NUM>. As shown in <FIG>, an outer surface of the forward end portion <NUM> includes two notches <NUM> on opposite lateral sides of the forward end portion <NUM>. The rearward end portion <NUM> includes a barbed outer surface <NUM> configured to receive the boot <NUM> thereon. The boot <NUM> is configured to provide strain relief for the cable fiber optic cable <NUM> and a weather resistant seal at the rearward end of the connector <NUM>.

The housing <NUM>, for example, an LC housing, is configured in a substantially square shape with a release lever <NUM> projecting outward from a top wall <NUM> of the housing <NUM>, as is typical with conventional LC connectors. As shown in <FIG> and <FIG>, the housing <NUM> includes a through bore <NUM> configured to receive the ferrule assembly <NUM> and the body <NUM> such that the ferrule <NUM> can be exposed at a front end <NUM> of the housing <NUM>. An inner surface of the top wall <NUM> of the housing <NUM> includes an alignment rib <NUM>. The alignment rib <NUM> is configured to be received by the radial slot <NUM> in the top wall of the body <NUM> and extending the length of the body <NUM>. The substantially square shape of the inner walls of the housing <NUM> and the substantially square middle portion <NUM> of the body also facilitate alignment of the housing <NUM> with the body <NUM>. These alignment features also prevent relative rotation between the body <NUM> and the housing <NUM>. Meanwhile, the two flattened regions <NUM> on the outer surface of the ferrule holder <NUM> cooperate with complementary interior surfaces <NUM>' of the housing <NUM> to facilitate alignment of the housing <NUM> with the ferrule assembly <NUM> and prevent relative rotation between the ferrule assembly <NUM> and the housing <NUM>.

The housing <NUM> further includes side walls <NUM> having resilient fingers <NUM> extending inward into the through bore <NUM>. Each of the resilient fingers <NUM> is cantilevered at its rear end <NUM>, and the free forward end <NUM> of each finger <NUM> is configured to engage one of the notches <NUM> in the outer surface on opposite lateral sides of the forward end portion <NUM> when the body <NUM> is inserted into the housing <NUM> to couple the housing <NUM> with the ferrule assembly <NUM>.

To field assemble the connector <NUM>, the boot <NUM> is configured to be slid over one of the deployed ferrule assemblies <NUM> and the fiber optic cable <NUM> preterminated by the ferrule assembly <NUM>. The fiber optic cable <NUM> is configured to be inserted into the radial slot <NUM> of the body <NUM>. In some aspects, the ferrule assembly <NUM> is configured to be inserted into the housing <NUM> using the two flattened regions <NUM> on the outer surface of the ferrule holder <NUM> and complementary interior surfaces <NUM>' of the housing <NUM> to facilitate alignment of the housing <NUM> with the ferrule assembly <NUM>. The body <NUM> configured to be slid axially in a direction toward the ferrule <NUM>. The forward facing shoulder 176a of the body <NUM> is configured to engage and compress the spring <NUM>. The body <NUM> is configured to be slid further in the axial direction using the alignment rib <NUM> and the radial slot <NUM> for alignment until the free forward ends <NUM> of the resilient fingers <NUM> of the housing <NUM> engage the notches <NUM> in the outer surface of the forward end portion <NUM> of the body <NUM> to secure the body <NUM> and ferrule assembly <NUM> to the housing <NUM>. The dust cap <NUM> needs to be removed from the ferrule <NUM> before the ferrule assembly <NUM> is inserted into the housing <NUM> and should be placed back on the ferrule <NUM> after the body <NUM> and ferrule assembly <NUM> are secured to the housing <NUM>.

In another aspect, after the fiber optic cable <NUM> is inserted into the radial slot <NUM> of the body <NUM>, the body <NUM> can be slid in a direction toward the ferrule <NUM> until a forward facing shoulder of the body <NUM> engages and compresses the spring <NUM>. The body <NUM> and the ferrule assembly <NUM> are configured to be slid further in the axial direction using the alignment rib <NUM> and the radial slot <NUM> for alignment until the free forward ends <NUM> of the resilient fingers <NUM> of the housing <NUM> engage the notches <NUM> in the outer surface of the forward end portion <NUM> of the body <NUM> to secure the body <NUM> and ferrule assembly <NUM> to the housing <NUM>.

Thus, the deployment assembly <NUM> is configured to be coupled with a plurality of preterminated fiber optic cables and to provide a cross-sectional footprint that is smaller than a cross-sectional footprint of a fiber optic connector that is configured to be assembled with the preterminated fiber optic cable such that the plurality of fiber optic cables can be easily and smoothly pushed, pulled, or blown together through a duct having an inner diameter than is less than a footprint the fiber optic connector. The fiber optic connector is configured to be field assembled with the plurality of preterminated fiber optic cables after the plurality of fiber optic cables are pushed, pulled, or blown together through a duct and the deployment assembly is removed from the plurality of preterminated fiber optic cables.

It should be appreciated that in some embodiments, the rod <NUM> can include an attachment structure similar to the attachment structure <NUM> described above, and the dust cap <NUM> can be replaced with a cylindrical dust cap with no attachment structure. In such embodiments, the attachment structure of the rod can clip onto the cylindrical dust cap.

Referring now to <FIG>, an alternative deployment assembly <NUM> for pushing, pulling, and/or blowing multiple preterminated fiber optic cables of a multi fiber cable through a duct. The deployment assembly <NUM> includes a sleeve <NUM>, for example, a crimp sleeve, having a through bore <NUM>. The sleeve <NUM> is sized such that the ferrule assemblies <NUM> of the preterminated fiber optic cables <NUM> and the multi fiber cable <NUM> can be received in the sleeve <NUM> and the sleeve <NUM> can be crimped onto an end of the multi fiber cable <NUM>. For example, the preterminated fiber optic cables <NUM> can be inserted, one at a time, from a rear end of the sleeve <NUM> and out of a forward end of the sleeve <NUM> until the multi fiber cable <NUM> is at a position in the sleeve <NUM> such that the sleeve <NUM> can be crimped thereon.

The deployment assembly <NUM> also includes a rod <NUM> such as, for example, a glass reinforced plastic (GRP) rod. The rod <NUM> extends from a forward end of the sleeve <NUM> to an end portion <NUM>. The rod <NUM> may include a first portion <NUM> configured to extend from the sleeve <NUM> and a second portion <NUM> configured to extend from the first portion <NUM> to the end portion <NUM>. The fiber optic cables <NUM> may be potted inside of the sleeve <NUM>. In some aspects, the rod <NUM> may include a pulling hook at the end portion <NUM> similar to the pulling hook <NUM> described above.

The second portion <NUM> of the rod <NUM> includes a plurality of cutouts <NUM>, each configured to receive a ferrule assembly <NUM> of one of the preterminated fiber optic cables <NUM>. The second portion <NUM> and the end portion <NUM> of the rod <NUM> comprise an outer diameter configured to be pulled, pushed, or blown through a duct. The cutouts <NUM> are configured to receive the ferrule assemblies <NUM> such that that ferrule assemblies <NUM> do not extend radially beyond the outer diameter of the second portion <NUM> of the rod <NUM>.

As best shown in <FIG> and <FIG>, the second portion <NUM> may include a circumferential notch <NUM> at a rearward end of each cutout <NUM>. The notches <NUM> are configured to permit the respective fiber optic cable <NUM> to be inserted into the respective notch <NUM> and routed to a longitudinal channel <NUM> configured to extend to the sleeve <NUM> such that the fiber optic cables <NUM> do not extend radially beyond the outer diameter of the second portion <NUM> of the rod <NUM>.

Additional embodiments include any one of the embodiments described above, where one or more of its components, functionalities or structures is interchanged with, replaced by or augmented by one or more of the components, functionalities, or structures of a different embodiment described above.

It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the scope of the present disclosure and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

Claim 1:
A deployment assembly for pulling, pushing, or blowing a plurality of preterminated fiber optic cables (<NUM>) of a multi fiber cable (<NUM>) through a duct having a cross sectional footprint smaller than a cross-sectional footprint of a fiber optic connector configured to be connected to the plurality of preterminated fiber optic cables (<NUM>), comprising:
a sleeve (<NUM>);
a rod (<NUM>) configured to be coupled with the sleeve (<NUM>);
a plurality of dust caps (<NUM>);
wherein the sleeve (<NUM>) is configured to receive a multi fiber cable (<NUM>) and to permit a plurality of preterminated fiber optic cables (<NUM>) of the multi fiber cable (<NUM>) to pass through the sleeve (<NUM>);
wherein the rod (<NUM>) includes a first end (<NUM>) configured to be coupled with the sleeve (<NUM>);
wherein each of the plurality of dust caps (<NUM>) is configured to be coupled with a ferrule (<NUM>) of one of the preterminated fiber optic cables (<NUM>);
wherein each of the plurality of dust caps (<NUM>) is configured to be coupled with the rod (<NUM>), thereby coupling the preterminated fiber optic cables (<NUM>) with the rod (<NUM>);
wherein the preterminated fiber optic cables (<NUM>) are configured to be assembled with a fiber optic connector (<NUM>);
wherein the deployment assembly (<NUM>) has a cross-sectional footprint that is smaller than a cross-sectional footprint of a fiber optic connector (<NUM>) that is configured to be assembled with the preterminated fiber optic cable (<NUM>);
wherein the plurality of preterminated fiber optic cables (<NUM>) are configured to be pushed, pulled, or blown together through a duct having an inner diameter that is less than a cross-sectional footprint of a fiber optic connector (<NUM>) that is configured to be assembled with the preterminated fiber optic cable (<NUM>).