Fiber closure sealing apparatus

Apparatus for enclosing a plurality of fiber optic cables in a sealed environment includes a housing, a lid, a hollow body projecting from the housing, at least one grommet disposed in the hollow body for securing one or more fiber optic cables in an orifice accessed by a slit provided therein and a cap disposed in front of the hollow body to compress the grommet and seal components passing through the grommet into the housing. The grommet is a single body with a plurality of orifices for receiving a plurality of fiber optic cables or a plurality of individually formed grommets each having one orifice.

FIELD OF INVENTION

The present invention generally relates to optical fiber enclosures and, more particularly, to an optical fiber enclosure having improved sealing capabilities for use in moisture or water prone outdoor environments.

BACKGROUND OF INVENTION

Fiber closures are used in outdoor applications (e.g., in flood zones, manholes for underground utility access and shipboard applications) to protect the terminals and interconnections of fiber optic cables contained within the closure. The fiber closure must be very well sealed to prevent damage to the fiber connections, splices and supporting framework. Prior designs have not been able to suitably seal around multiple fiber cables entering a closure simultaneously. That is, as the number of fiber cables that access a fiber closure increases, so does the number of openings in the fiber closure for water or moisture to enter; thereby possibly leading to fiber damage. One possible solution to the problem of multiple fiber cable sealing is to use heat shrink tubing around each of the cables as they enter an enclosure. Unfortunately, heat shrink tubing is not reusable (thus leading to additional cost and time for accessing a closure or cable each time a cable must be handled) and does not allow for adequate mounting of a plurality of cables within the moisture or water prone environment.

SUMMARY OF THE INVENTION

These and other deficiencies of the prior art are addressed by the present invention of an apparatus for enclosing a plurality of fiber optic cables in a sealed environment including, in one embodiment, a housing, a lid, a hollow body projecting from the housing, at least one grommet disposed in the hollow body for securing one or more fiber optic cables in an orifice accessed by a slit provided therein and a cap disposed in front of the hollow body to compress the grommet and seal components passing through the grommet into the housing. The housing is substantially rectangular in shape and has a front face having an opening where the hollow body projects from. In one embodiment of the invention, the grommet is a single body with a plurality of orifices for receiving a plurality of fiber optic cables. In such embodiment, the grommet has a plurality of slits corresponding to the plurality of orifices for gaining access to the plurality of orifices. In an alternate embodiment of the invention, the grommet is a plurality of individually formed grommets; each grommet comprising one orifice. Each of the plurality of individual grommets has a slit on a side of the grommet for accessing the orifice. In such embodiment, the plurality of individual grommets are grouped in a matrix that is sized to fit in the hollow body. The grommet slit is either a wavy line design cut along one face of the gromment or a straight line design cut along two or more faces of the grommet.

In one embodiment of the invention, the cap has a tray-like shape with a plurality of flanges that correspond to a plurality of flanges provided on the hollow body. In an alternate embodiment, the cap is a flat plate construction. In either embodiment, the cap has a plurality of openings, each cap opening corresponding to a grommet orifice.

The lid is secured to the housing using a plurality of stud and nut combinations or via a hinge assembly and one or more screws passing through the lid into the housing.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1depicts an isometric view of a first embodiment of the fiber closure sealing apparatus of the subject invention. Specifically, a fiber closure sealing apparatus100is shown that is capable of receiving a plurality of fiber optic cables (not shown), fanning out said plurality of fiber optic cables into a plurality of individual optical fibers, terminating such individual optical fibers with connectors to facilitate connections of said optical fibers with a second plurality of individual optical fibers in a weather tight (or otherwise waterproof) environment.

The fiber closure sealing apparatus100comprises a housing102with a lid104disposed over the housing to form an enclosure. The lid104is secured to the housing102via a plurality of stud and nut combinations106provided at strategically placed intervals about the housing102with accommodating holes provided in the lid104. The housing102or lid104may have a gasket or other type of sealing member, (not shown) provided therebetween to provide a substantially watertight seal between the housing102and the lid104.

The housing102has a front face118that has an opening110. The opening110is a plurality of housing orifices132formed in the front face118(see FIG.4). The opening110communicates with a pass-through body108that extends perpendicularly away from the front face118. Specifically, the pass-through body108is an interface for receiving a plurality of fiber optic cables from an outside environment and providing them to the interior of the fiber closure sealing apparatus100to make the appropriate connections therein. In one embodiment, the pass-through body108is a substantially rectangular body to facilitate design, fabrication and construction of the apparatus100. The pass-through body108is terminated by an end cap112. Specifically, the end cap112is secured to the pass-through body108by a second plurality of stud and nut combinations114. Additionally, the end cap112is provided with a plurality of openings116for accommodating fiber optic cables passing between an outside environment and the apparatus100.

FIG. 2depicts a second isometric view, partially exploded, of the apparatus100of FIG.1. The lid104is shown removed from the housing102by disassembling the stud and nut combinations106so as to gain access to the interior of housing102for the purposes of connecting individual fiber optic cables (described in greater detail below). The pass-through body108and end cap112are shown in greater detail as follows. Specifically, and in one embodiment of the invention, the end cap112is a substantially rectangular, tray-shaped component that has a plurality of flanges120extending therefrom. The end cap112is dimensioned such that it fits inside of pass-through body108at a front opening128. The pass-through body108also includes a plurality of flanges122provided at the front opening128. The pass-through body flanges122coincide with the end cap flanges120thereby providing the necessary mounting and sealing surfaces to join these two components.

A plurality of cable grommets124are disposed within the pass-through body108from the pass-through body front opening128extending to a pass-through body rear opening130(not seenFIGS. 1or2, but seen in FIG.4). In one embodiment of the subject invention, six cable grommets124are provided in the pass-through body108. One skilled in the art will realize that any number of cable grommets may be designed and placed in the pass-through body108as necessary for holding the desired number of cables. Each of the cable grommets124includes a cable grommet orifice126which extends longitudinally through the cable grommet124for retaining a fiber optic cable in the pass-through body108from the pass-through body front opening128to the pass-through body rear opening130. Each cable grommet orifice126is axially aligned with a corresponding housing orifice132and end cap opening116.

One skilled in the art will realize that there can be various alternate embodiments that are within the spirit and scope of the invention. For example, the fiber closure sealing apparatus100need not have a lid104, but can be formed of a housing102made of two housing halves or a plurality of housing sides that are held together by some type of fastening means or permanently attached to one another. The opening110can be one or more openings placed on any of the halves or housing sides for optimization of a particular design. The shape of the apparatus100need not be a rectangular one, but any desired shape (irregular, asymmetric, round, oval, square and the like) to optimize the design for a particular application.

Details of the cable grommet124are depicted inFIGS. 5-7. Specifically,FIG. 5Ashows a side view of one embodiment of the cable grommet124for receiving a fiber optic cable. The cable grommet124has a cable threading side502which includes a slit504. The slit504facilitates separating the cable threading side502temporarily so as to thread the fiber optic cable into the cable grommet orifice126.FIG. 5Bdepicts a front view of the cable grommet124as viewed along lines5B—5B of FIG.5A. Specifically, as one pulls apart the cable threading side502along the slit504a fiber optic cable is snugly provided in the cable grommet orifice. Accordingly, a single cable grommet124serves as a building block for securing a single fiber optic cable in the fiber closure sealing apparatus100. In one particular example of the cable grommet124, the slit504has the form of a straight slit extending longitudinally along the threading side502, then making a right angle turn towards the edge of the cable grommet124to an adjacent face130(this particular embodiment seen more distinctly in FIG.2). In an alternate embodiment of the cable grommet124, the slit504is formed as a wavy line cutout along the threading side502. The wavy line form may take the shape of a substantially sinusoidal type curve, but one skilled in the art will realize that any form of the slit is possible so long as its provides access to the cable grommet orifice126and provides for a substantially tightly sealed structure as explained below.

FIGS. 6A and 6Bdepict respectively side views and front views of a plurality of cable grommets124used in a specific embodiment of the invention. Specifically, six cable grommets124are shown provided in an array of three columns by two rows so as to secure six individual fiber optic cables. The grommets are arranged in pairs such that their respective cable threading sides502are opposite one another so as to facilitate threading of the fiber optic cable through their respective slits504. In instances where there are less than six fiber cables accessing the apparatus100, a “blank” grommet (having no grommet orifice) replaces one or more cable grommets124. Once the threading operation is completed, the plurality of grommets124is placed into the pass-through body108(with the cables secured therein) and is threaded into the housing102. Each of the plurality of cable openings116in the end cap112coincide with a cable grommet orifice126. Accordingly, as end cap112is placed in pass-through body front opening128and secured to the pass-through body108, a compressive force is applied by the end cap112to the plurality of cable grommets124(backed up against front face118) thereby creating a weather tight (water tight, moisture-proof and the like) seal between the cables, grommets124, and pass-through body108.

FIG. 3depicts a front elevation view of a second embodiment of the fiber sealing closure apparatus100in accordance with the subject invention. Specifically, this second embodiment includes a housing102and a lid104as described earlier; however, the lid104is not secured to the housing102by a plurality of stud and nut combinations, but by a hinge assembly302attached to one side of the lid104and housing102. The hinged lid104is secured to the housing102by one or more fasteners304(e.g., screw, nut and bolt combination and the like) provided in a recess306in the hinged lid104. An appropriate gasket or sealing member (now shown) is also provided either on housing102or lid104in the manner prescribed earlier to seal the outside environment from the interior of the apparatus100. Additionally, in this embodiment, the end cap112is of a slightly different configuration than the one described in the first embodiment. Specifically, the end cap112is a flat plate type component that is secured to the pass-through body108by two second stud and nut combinations114disposed at either end of the plate.

Additional features of the pass-through body108and cable grommets are seen in FIG.4. More specifically, the pass-through body108is depicted as a rectangular body having a pass-though body rear opening130communicating with the front face opening110of front face118of the housing102. The partially exploded view ofFIG. 4shows a grommet assembly402replacing the plurality of individual cable grommets124seen in the first embodiment. More specifically, grommet assembly402is a substantially solid block of material provided with the appropriate plurality of slits502provided on opposite faces of the grommet assembly402for accommodating any desired number of fiber optical cables. In the specific depicted embodiment ofFIG. 4, three slits502are shown on a first face412on the top side of grommet assembly402. It will be understood by those skilled in the art that there could be additional slits on a side face or bottom face of the grommet assembly402for accommodating additional optical fiber cables. Additionally, the flat face plate type end cap112is more readily seen in FIG.4.

When a fiber optic cable4001, is threaded into a slit502of one of the cable grommet orifices126, it is then passed into the housing102for appropriate termination and connection to a second fiber optic cable4002. Namely, the first fiber optic cable4001is threaded through a plurality of clips404so as to secure the fiber to prevent unnecessary physical bending of the optical cable to prevent damage thereto. The first fiber optic cable4001, then fans out into a plurality of individual optical fibers4061, and in one particular embodiment depicted shows twelve individual optical fibers fanning out from a typical ribbon cable. Each of the individual optical fibers4061, is terminated with an optical connector4081which is then attached to a frame410disposed within the housing102.

A corresponding number of second fiber optic connectors4082are connected to the frame410. Each of the corresponding second fiber optic connectors4082are attached to a second plurality of individual optical fibers4062which are then fanned-in to the second fiber optic cable4002. In this particular embodiment, the second fiber optic cable4002is a ribbon cable having twelve individual optical fibers contained therein. The second fiber optic cable4002is then threaded through a plurality of clips404along the frame so as to physically limit movement bending or damage thereto. The second fiber optic cable4002is then routed outside the enclosure102through the pass-through body108via one of the slits502in the grommet assembly402. As discussed in the first embodiment, the end cap112in the second embodiment is so dimensioned so as to place a compressive forces against the grommet assembly402when it is secured to the pass-through body108by the plurality of stud and nut combinations114. It will be understood that the interior of the housing102in the first embodiment is substantially similar to that of the second embodiment described and depicted in FIG.4. That is, the necessary frame hardware and connectors are provided so that any one of a plurality of incoming optical fiber cables can be fanned out, connected to the frame and have a corresponding number of return optical fibers connected to the frame and bundled together to form an output optical fiber cable.

FIGS. 7A and 7Bdepict a more detailed view of the second embodiment of the invention including the grommet block assembly402. Specifically, grommet block assembly402is a unitary component having a plurality of grommet portions702arranged within the block.FIG. 7Ashows a side view of the grommet block assembly402depicting three grommet areas each having its own slit502provided therein. One skilled in the art will realize that any number of grommet areas702can be provided and in this specific embodiment there are six such locations, three on opposing sides of the grommet block.FIG. 7Bis a view of the grommet block assembly402looking along lines7B—7B of FIG.7A. Specifically, the six grommet areas702are more readily seen by viewing the corresponding cable grommet orifice126provided in the block assembly402. Grommet mounting holes704are provided on either end of the grommet block402so as to provide room for accommodating the second stud and nut assemblies passing through the pass-through body108when such grommet block assembly402is used to secure the plurality of fiber optic cables. One skilled in the art will realize that any number of areas702and corresponding cable grommet orifices126may be provided in the grommet block assembly402. In one embodiment of the invention, rubber is used as the material of which the grommets124or grommet assembly402is formed. Preferably, the material is selected from the group consisting of silicone rubber, neoprene rubber and neoprene foam rubber. However, one skilled in the art will realize that other materials are suitable for the purposes of holding cables and sealing them in the apparatus100.