Patent Description:
Fiber optical communication systems typically use a network of fiber optic cables to transmit large volumes of data. Typical fiber optical connectors include a ferrule that supports an end portion of an optical fiber. When two fiber optical connectors are interconnected, end faces of the ferrules, on each connector, directly oppose one another. Thus, the optical fibers, which are supported by each ferrule, are also directly opposed to each other. Furthermore, springs in each connector bias the optical fibers towards each other when the connectors are in this interconnected state. An optical signal can then be transmitted from one optical fiber to the other optical fiber.

Traditionally, the ferrule may be disposed in a ferrule holder carrier, which is then secured to an outer barrel. Conventional outer barrels include a clamp shell arrangement in order to easily fit the barrel around and over the ferrule holder carrier and the cable. Thus, the clamp shell may open in order to move the barrel over and around these components. An outer housing may then be disposed over the clamp shell in order to provide a secure and stable connector assembly. <INSERT PAGE 1A>.

Document <CIT> discloses an optical fiber connector comprising an inner housing, an outer housing and a ferrule assembly.

Document <CIT> discloses an optical fiber connector comprising an inner housing, an outer housing, a ferrule assembly and a sleeve.

It may be desirable to provide a hardened optical fiber connector that overcomes one or more problems of conventional prior art connectors that are recognized by persons having ordinary skill in the art.

A fiber optic connector according to the invention is disclosed in any one of the claims <NUM>-<NUM>.

Features and advantages of the present disclosure are described in, and will be apparent from, the following Brief Description of the Drawings and Detailed Description.

Throughout the description, like reference numerals will refer to like parts in the various drawing figures. As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents, unless the context clearly dictates otherwise.

<FIG> illustrate an exemplary fiber optical connector <NUM>, for example, a hardened fiber optic connector, for terminating an optical fiber cable <NUM>. The optical fiber cable <NUM> may include one or more fibers; however, the connector <NUM> is configured to terminate a single fiber <NUM>. The fiber optical connector <NUM> includes a forward end <NUM> configured to be coupled with a fiber optic receptacle and a rearward end <NUM> into which the optical fiber cable <NUM> extends. The fiber optical connector <NUM> extends in a longitudinal axial direction from the forward end <NUM> to the rearward end <NUM>. It should be appreciated that the mating between the fiber optical connector <NUM> and the receptacle may be secured using a threaded engagement, a quarter-turn lock, a quick release, a push-pull latch, or a bayonet configuration.

The connector <NUM> includes an inner housing <NUM>, a connector sub-assembly <NUM>, an outer housing <NUM>, and a crimp sleeve <NUM>. The outer housing <NUM> surrounds at least a portion of the inner housing <NUM> and the connector sub-assembly <NUM>, and the inner housing <NUM> is a single piece of unitary construction (i.e., a monolithic structure). Outer housing <NUM> may include a rigid material that is sufficient to withstand environmental conditions.

The fiber optical connector <NUM> uses a connector subassembly <NUM> of the SC type, but other types of connector assemblies such as LC, FC, ST, MT, and MT-RJ are contemplated by the present invention by using a suitable crimp housing. As illustrated, the connector sub-assembly <NUM> may be an industry standard SC type connector assembly having a connector body <NUM>, a ferrule <NUM> in a ferrule basket <NUM>, a spring <NUM>, and a mandrel <NUM>. As would be understood by persons skilled in the art, the ferrule <NUM> is held by the ferrule basket <NUM>, which is axially slidable relative to the connector body <NUM> against a force of the spring <NUM> as limited by the connector body <NUM> and the mandrel <NUM>.

As shown in <FIG>, the inner housing <NUM> includes a first end <NUM> toward the forward end <NUM> of the connector <NUM> and a second end <NUM> toward the rearward end <NUM> of the connector <NUM>. The inner housing <NUM> includes a forward flange portion <NUM> having flattened outer peripheral portions <NUM> at opposed top and bottom regions of the forward flange portion <NUM>. The flattened peripheral portions <NUM> of the forward flange portion <NUM> are configured to engage complementary portions of the outer housing <NUM> to prevent rotation of the inner housing <NUM> relative to the outer housing <NUM>.

Referring to <FIG> and <FIG>, the inner housing <NUM> includes a body portion <NUM> extending from the forward flange portion <NUM> to a rearward flange portion <NUM> in the longitudinal direction and a boot portion <NUM> that extends rearward from the rearward flange portion <NUM> in the longitudinal direction. The boot portion <NUM> may be made from any conventional bendable material to provide strain relief for the cable <NUM>. The boot portion <NUM> may include one or more notched portions <NUM> to enhance bendability of the boot portion <NUM>. The boot portion <NUM> of the inner housing <NUM> may be a flexible member that provides an interface between the connector <NUM> and the optical fiber cable <NUM> and permits the optical fiber cable <NUM> to bend and/or and rotate relative to the connector <NUM>.

The forward flange portion <NUM> includes a pair of opposed outer side walls <NUM> between the flattened peripheral portions <NUM> at the top and bottom regions. The body portion <NUM> has opposed outer side walls <NUM> aligned with the side walls <NUM> in the longitudinal direction. A side wall <NUM> to side wall <NUM> dimension in a transverse direction perpendicular to the longitudinal direction is less than a side wall <NUM> to side wall <NUM> dimension in the transverse direction. Thus, the inner housing <NUM> defines radially-extending surfaces <NUM> at the interface between the side walls <NUM> and the side walls <NUM> that face rearward in the longitudinal direction. Similarly, the rearward flange portion <NUM> includes a pair of opposed side walls <NUM> aligned with the side walls <NUM> and the side walls <NUM> in the longitudinal direction. A side wall <NUM> to side wall <NUM> dimension in a transverse direction perpendicular to the longitudinal direction is less than a side wall <NUM> to side wall <NUM> dimension in the transverse direction. Thus, the inner housing <NUM> defines radially-extending surfaces <NUM> at the interface between the side walls <NUM> and the side walls <NUM> that face forward in the longitudinal direction. As discussed in more detail below, the rearward facing surfaces <NUM> and the forward facing surfaces <NUM> are configured to secure the outer housing <NUM> to the inner housing <NUM>.

As shown in <FIG>, the inner housing <NUM> has an inner wall <NUM> that extends in the longitudinal direction and a projection extending inward from the inner wall <NUM>. The projection may be an annular projection or one or more axial projections that are spaced apart from one another about the periphery of the inner wall <NUM>. The projection thus defines a radially-extending surface <NUM> that faces forward in the longitudinal direction and a radially-extending surface <NUM> that faces rearward in the longitudinal direction.

The outer housing <NUM> has a generally cylindrical shape with a first end <NUM> and a second end <NUM>. The outer housing <NUM> generally protects the connector sub-assembly <NUM> and in some embodiments may also key the fiber optical connector <NUM> with the respective mating receptacle. Moreover, the outer housing <NUM> includes a through passageway between the first end <NUM> and the second end <NUM>. As mentioned above, the passageway of the outer housing <NUM> is keyed so that inner housing <NUM> is inhibited from rotating when the fiber optical connector <NUM> is assembled. For example, an inner surface <NUM> of the outer housing includes flattened regions <NUM> that are configured to receive the complementary flattened peripheral portions <NUM> of the forward flange portion <NUM> to prevent rotation of the inner housing <NUM> relative to the outer housing <NUM>. Additionally, the inner surface <NUM> of the outer housing <NUM> forming the passageway has one or more internal shoulders 178a, 178b configured to inhibit the inner housing <NUM> from being inserted into the outer housing <NUM> beyond a predetermined position.

The outer housing <NUM> includes at least one opening <NUM> extending from a medial portion of the outer housing <NUM> to the first end <NUM>. In this case, the outer housing <NUM> includes a pair of opposed openings <NUM> at the first end <NUM>, thereby defining alignment portions or fingers 149a, 149b. In addition to aligning the outer housing <NUM> with the receptacle during mating, alignment fingers 149a, 149b may protect the connector subassembly <NUM>.

As shown in <FIG>, the alignment fingers 149a, 149b may have different shapes and/or sizes so that the connector <NUM> can only mate with the receptacle in one orientation. It should be appreciated that the alignment fingers 149a, 149b may include alignment indicia so that a technician can quickly and easily mate the connector <NUM> with the receptacle. After the alignment fingers 149a, 149b are seated into the receptacle, the technician can engage the external threads of a coupling nut (not shown) with complementary internal threads of the receptacle to provide a secure optical connection.

As best illustrated in <FIG> and <FIG>, the inner housing <NUM> has a generally flat outer wall <NUM> at top and bottom regions between the side walls <NUM>. The inner housing <NUM> further includes one or more projections <NUM> extending outward from the outer wall <NUM>. The one or more projections <NUM> are configured to substantially match the inner surface <NUM> of the outer housing <NUM> to seal the passageway. The portions of the flat outer wall <NUM> without the one or more projections facilitate sealing by the one or more projections <NUM> and reduce the overall material thickness to assist with the molding process, as would be understood by persons skilled in the art.

Referring to <FIG> and <FIG>, the connector <NUM> includes a crimp ferrule <NUM> configured to be inserted into the fiber optic cable <NUM> between the one or more fibers <NUM> and an outer jacket <NUM> of the cable <NUM>. The crimp ferrule <NUM> protects the one or more fibers <NUM> during termination of the cable <NUM> with the connector <NUM>. The fiber optic cable <NUM> may includes one or more strengthening members <NUM>, for example, Kevlar strands that run through the length of the fiber optic cable <NUM> along side the one or more fibers <NUM>.

As shown in <FIG>, the crimp sleeve <NUM> extends over a rear portion of the mandrel <NUM> to a shoulder portion <NUM> of the mandrel <NUM> and over a forward portion of the fiber optic cable <NUM>. The crimp sleeve <NUM> includes an annular barb <NUM> or one or more circumferential barb portions at its rearward end that are configured to secure the inner housing <NUM> relative to the crimp sleeve <NUM>. In particular, the projection that extends inward from the inner wall <NUM> is retained between a tapered region <NUM> of the crimp sleeve <NUM>, which results from crimping onto the mandrel <NUM>, and the annular barb <NUM>.

With one of the strengthening members <NUM> disposed on a radially outer surface of the mandrel <NUM>, the crimp sleeve <NUM> is crimped onto the mandrel <NUM> and the fiber optic cable <NUM> to secure the connector sub-assembly <NUM> to the fiber optic cable <NUM>.

When terminating the fiber optic cable <NUM> with the connector <NUM>, which typically occurs at a manufacturing facility, the coupling nut and the outer housing <NUM> are slid over the fiber optic cable <NUM>, followed by the inner housing <NUM> and then the mandrel <NUM>. The crimp ferrule <NUM> is then inserted into the end of the fiber optic cable <NUM>. A fiber <NUM> of the cable <NUM> is terminated with the ferrule <NUM>, and the connector sub-assembly <NUM> is placed adjacent the fiber optic cable <NUM>. A strengthening member <NUM> may be placed onto an outer surface of the rear portion of the mandrel <NUM>. The crimp sleeve <NUM> is then moved forward over the rearward portion of the mandrel <NUM> until reaching the shoulder <NUM>, while the rear portion of the mandrel <NUM> surrounds the fiber optic cable <NUM>. The crimp sleeve <NUM> is crimped onto the mandrel <NUM> and the fiber optic cable <NUM> to secure the cable <NUM> to the connector sub-assembly <NUM>.

Next, the inner housing <NUM> is slid forward until the projection that extends inward from the inner wall <NUM> is retained between the tapered region <NUM> of the crimp sleeve <NUM> and the annular barb <NUM> at the rearward end of the crimp sleeve <NUM>. The elastic nature of the inner housing <NUM>, which is made, for example, from rubber or any known elastomer, enables the inner housing <NUM> to defect over the annular barb <NUM> and onto the outer surface of the inner housing <NUM>. The outer housing <NUM> is the slide forward over the inner housing <NUM> until a shoulder <NUM> of the outer housing <NUM> reaches the rearward facing surfaces <NUM> of the inner housing <NUM> and the rear end <NUM> of the outer housing <NUM> is positioned forward of the forward facing surfaces <NUM> of the rearward flange portion <NUM>. The coupling nut can then be slid forward to a position limited by projections from the outer surface of the outer housing so as to be configured to couple the connector <NUM> to the receptacle.

<FIG> and <FIG> illustrate another exemplary fiber optical connector <NUM>', for example, a hardened fiber optic connector, for attachment of an optical fiber cable with a ferrule. Connector <NUM>' includes the inner housing <NUM>, the connector sub-assembly <NUM>, and the crimp sleeve <NUM> as described above in connection with the embodiment of <FIG>. The outer housing <NUM>' is similar to the outer housing <NUM> described above, but the first end <NUM>' of the outer housing <NUM>' includes only a single projection <NUM>' disposed radially outward of ferrule housing sub-assembly <NUM>. Also, as shown in <FIG>, the single projection <NUM>' has a length configured such that a forward end <NUM> of the projection <NUM>' does not extend beyond a forward end <NUM> of the ferrule <NUM> of the ferrule housing sub-assembly <NUM>.

<FIG> illustrate another exemplary fiber optical connector <NUM>, for example, a hardened fiber optic connector, for attachment of an optical fiber cable with a ferrule. The connector <NUM> includes a connector sub-assembly <NUM>, an outer housing <NUM>, and a crimp sleeve <NUM>, which are similar to the same parts described above in connection with the embodiment of <FIG>. The connector <NUM> further includes a first inner housing 220a and a second inner housing 220b. The outer housing <NUM> surrounds the first inner housing 220a and at least a portion of the second inner housing 220a and the connector sub-assembly <NUM>. The first inner housing 220a is constructed of a relatively rigid plastic that is more rigid that the second inner housing 220b, which is constructed of rubber or an elastomer. Outer housing <NUM> may include a rigid material that is sufficient to withstand environmental conditions.

As shown in <FIG>, the first inner housing 220a is disposed toward the forward end <NUM> of the connector <NUM> relative to the second inner housing 220b. The first inner housing 220a has a first forward end <NUM> configured to engage a shoulder <NUM> defined by an inner surface <NUM> of the outer housing <NUM> to limit the distance that the first inner housing 220a can move in the forward direction relative to the outer housing <NUM>. A second rearward end <NUM> of the first inner housing 220a includes a radially outward extending barb <NUM> toward the rearward end <NUM> of the connector <NUM>. The first forward end <NUM> of the first inner housing 220a includes flattened outer peripheral portions <NUM> at opposed top and bottom regions of the first inner housing 220a. The flattened peripheral portions <NUM> are configured to engage complementary portions of the outer housing <NUM> to prevent rotation of the first inner housing 220a relative to the outer housing <NUM>.

Referring to <FIG> and <FIG>, the second inner housing 220b includes a body portion <NUM> extending from the first inner housing 220a to a rearward boot portion <NUM> that extends rearward in the longitudinal direction. The boot portion <NUM> may be made from any conventional bendable material to provide strain relief for the cable <NUM>. The boot portion <NUM> may include one or more notched portions <NUM> to enhance bendability of the boot portion <NUM>. The boot portion <NUM> of the second inner housing 220b may be a flexible member that provides an interface between the connector <NUM> and the optical fiber cable <NUM> and permits the optical fiber cable <NUM> to bend and/or and rotate relative to the connector <NUM>.

As shown in <FIG>, the second inner housing 220b has an inner wall <NUM> that extends in the longitudinal direction and a projection <NUM> extending inward from the inner wall <NUM>. The projection <NUM> may be an annular projection or one or more axial projections that are spaced apart from one another about the periphery of the inner wall <NUM>. The projection <NUM> thus defines a radially-extending surface <NUM> that faces forward in the longitudinal direction and a radially-extending surface <NUM> that faces rearward in the longitudinal direction.

The outer housing <NUM> has a generally cylindrical shape with a first end <NUM> and a second end <NUM>. The outer housing <NUM> generally protects the connector sub-assembly <NUM> and in some embodiments may also key the fiber optical connector <NUM> with the respective mating receptacle. Moreover, the outer housing <NUM> includes a through passageway between the first end <NUM> and the second end <NUM>. As mentioned above, the passageway of the outer housing <NUM> is keyed so that the first inner housing 220a is inhibited from rotating when the fiber optical connector <NUM> is assembled. For example, an inner surface <NUM> of the outer housing includes flattened regions <NUM> that are configured to receive the complementary flattened peripheral portions <NUM> of the forward flange portion <NUM> to prevent rotation of the first inner housing 220a relative to the outer housing <NUM>. Additionally, the inner surface <NUM> of the outer housing <NUM> forming the passageway has the shoulder <NUM> configured to inhibit the first inner housing 220a from being inserted into the outer housing <NUM> beyond a predetermined position.

The outer housing <NUM> includes at least one opening <NUM> extending from a medial portion of the outer housing <NUM> to the first end <NUM>. In this case, the outer housing <NUM> includes a pair of opposed openings <NUM> at the first end <NUM>, thereby defining alignment portions or fingers 249a, 249b. In addition to aligning the outer housing <NUM> with the receptacle during mating, alignment fingers 249a, 249b may protect the connector sub-assembly <NUM>.

As shown in <FIG>, the alignment fingers 249a, 249b may have different shapes and/or sizes so that the connector <NUM> can only mate with the receptacle in one orientation. It should be appreciated that the alignment fingers 249a, 249b may include alignment indicia so that a technician can quickly and easily mate the connector <NUM> with the receptacle. After the alignment fingers 249a, 249b are seated into the receptacle, the technician can engage the external threads of a coupling nut (not shown) with complementary internal threads of the receptacle to provide a secure optical connection.

As best illustrated in <FIG>, the second inner housing 220b has a generally flat outer wall <NUM> at top and bottom regions between the side walls <NUM>. The second inner housing 220b further includes one or more projections <NUM> extending outward from the outer wall <NUM>. The one or more projections <NUM> are configured to substantially match the inner surface <NUM> of the outer housing <NUM> to seal the passageway. The portions of the flat outer wall <NUM> without the one or more projections facilitate sealing by the one or more projections <NUM> and reduce the overall material thickness to assist with the molding process, as would be understood by persons skilled in the art.

Referring to <FIG>, the connector <NUM> includes a crimp ferrule <NUM> configured to be inserted into the fiber optic cable <NUM> between the one or more fibers <NUM> and an outer jacket <NUM> of the cable <NUM>. The crimp ferrule <NUM> protects the one or more fibers <NUM> during termination of the cable <NUM> with the connector <NUM>. The fiber optic cable <NUM> may includes one or more strengthening members <NUM>, for example, Kevlar strands that run through the length of the fiber optic cable <NUM> along side the one or more fibers <NUM>.

As shown in <FIG> and <FIG>, the crimp sleeve <NUM> extends over a rear portion of the mandrel <NUM> to a shoulder portion <NUM> of the mandrel <NUM> and over a forward portion of the fiber optic cable <NUM>. The crimp sleeve <NUM> includes an annular barb <NUM> or one or more circumferential barb portions at its rearward end that are configured to secure the second inner housing 220b relative to the crimp sleeve <NUM>. With one of the strengthening members <NUM> disposed on a radially outer surface of the mandrel <NUM>, the crimp sleeve <NUM> is crimped onto the mandrel <NUM> and the fiber optic cable <NUM> to secure the connector sub-assembly <NUM> to the fiber optic cable <NUM>.

The foregoing description of exemplary embodiments provides illustration and description, but is not intended to be exhaustive or to limit the embodiments described herein to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the embodiments.

Although the invention has been described in detail above, it is expressly understood that it will be apparent to persons skilled in the relevant art that the invention may scope be modified without departing from the of the invention. Various changes of form, design, or arrangement may be made to the invention without departing from the scope of the invention. Therefore, the above mentioned description is to be considered exemplary, rather than limiting, and the scope of the invention is that defined in the following claims.

Claim 1:
A fiber optic connector for terminating a fiber optic cable, the connector comprising:
an inner housing (<NUM>; 220a, 220b);
an outer housing (<NUM>; <NUM>'; <NUM>) disposed radially outward of the inner housing (<NUM>; 220a, 220b);
a connector sub-assembly (<NUM>; <NUM>) that includes a ferrule basket (<NUM>; <NUM>) configured to receive a ferrule (<NUM>; <NUM>) that terminates a fiber of the fiber optic cable (<NUM>); and
a crimp sleeve (<NUM>; <NUM>) that is configured to surround and to be crimped onto a rearward portion of the connector sub-assembly (<NUM>; <NUM>) and configured to surround and to be crimped onto an end portion of the fiber optic cable (<NUM>),
wherein the inner housing (<NUM>; 220a, 220b) is configured to be securely disposed about the crimp sleeve (<NUM>; <NUM>), and
wherein the outer housing (<NUM>; <NUM>'; <NUM>) is configured to be securely disposed about the inner housing (<NUM>; 220a, 220b),
wherein the crimp sleeve (<NUM>; <NUM>) is configured to be crimped onto a mandrel (<NUM>; <NUM>) at a rear end of the connector sub-assembly (<NUM>; <NUM>); and
wherein the crimp sleeve (<NUM>) extends over a rear portion of the mandrel (<NUM>; <NUM>) to a shoulder portion (<NUM>; <NUM>) of the mandrel (<NUM>; <NUM>) and is configured to extend over a forward portion of the fiber optic cable (<NUM>);
characterized in that the crimp sleeve (<NUM>; <NUM>) includes an annular barb (<NUM>; <NUM>) or one or more circumferential barb portions at its rearward end that are configured to secure the inner housing (<NUM>; 220b) relative to the crimp sleeve (<NUM>; <NUM>).