Cable seal for submerged enclosures

A cable sealing arrangement is provided for limiting the ingress of fluid into a location about a cable, such as a telephone wire enclosure, which generally includes a fitting, two sealing members, and two nuts. The sealing arrangement provides multiple redundant seals defined by the interfaces of tapered surfaces on the sealing members and the fitting, as well as, the interfaces of tapered surfaces on the sealing members and the nuts. By tightening the nuts onto the fitting, the nuts cause compression of the sealing members resulting in tight engagement of a cable.

FIELD OF THE INVENTION
 This invention relates to sealing arrangements and, more particularly, to
 sealing arrangements for preventing the ingress of fluid into a location
 about a cable, such as into a telephone wire enclosure.
 BACKGROUND OF INVENTION
 Extensive numbers of telephone wire enclosures are located in harsh
 environmental settings, including sub-grade locations that are under water
 or susceptible to flooding. Fluid is prevalent in these settings, and
 there is great concern in preventing the ingress of fluid into the
 enclosures, which may denigrate, or altogether destroy, the telephone wire
 connections within the enclosure. The concern is even greater where fiber
 optic cables are used.
 One of the most susceptible locations for fluid ingress is about a cable at
 the point of entry of the cable into the enclosure. To restrict the
 ingress of fluid into an enclosure at a cable's point of entry, seals have
 been used in the prior art. The various prior art seals provide different
 degrees of sealing over extended periods of time, depending upon such
 factors as the extent of plastic deformation caused by changes in
 temperature, excessive and/or uneven stresses, etc.
 SUMMARY OF THE INVENTION
 To overcome shortcomings in the prior art, a sealing arrangement is
 provided for use with a cable at a location where the ingress of fluid
 about the cable is a concern, such as at the point of entry into a
 telephone wire enclosure. The sealing arrangement preferably has multiple
 sealing interfaces which define multiple redundant seals. The multiple
 sealing interfaces restrict the ingress of fluid into the location about
 the cable at the point of entry of the cable into the location. As used
 herein, a "cable" can be any of standard copper cables, fiber optic cables
 or cables of other construction and/or materials.
 The sealing arrangement generally comprises a fitting, two sealing members,
 and two nuts. The sealing members are formed to be at least partially
 disposed in the fitting, with the nuts being used to tighten against the
 sealing members and enhance the sealing ability of the arrangement.
 The fitting has a passageway extending therethrough, which is preferably
 generally venturi-shaped, with two tapered converging portions being
 disposed end-to-end. Also, the sealing members are each formed with a
 channel, dimensioned to allow the passage therethrough of the cable, and,
 preferably, a tapered fitting engaging portion. With the sealing members
 being seated in the passageway, the channels of the sealing members are
 generally coaxially aligned, and the tapered fitting engaging portions of
 the sealing members respectively contact the tapered converging portions
 of the passageway to define two sealing interfaces. With at least two
 sealing interfaces, and a cable passing through the channels of the
 sealing members, the ingress of fluid into an enclosure about the cable
 can be reduced.
 Additionally, the sealing members can respectively be formed with tapered
 nut engaging portions. The nuts are preferably each formed with a ramped
 smooth compression surface for pressing against the tapered nut engaging
 surface of one of the sealing members to cause compression thereof upon
 being tightened onto the fitting. The interfaces of the respective
 compression surfaces and the nut engaging surfaces provide additional
 seals in the arrangement which limit the amount of fluid that can migrate
 about a cable.
 The compression of the sealing members by the nuts causes distortion of the
 sealing members. With the sealing members being in abutting contact and/or
 due to the angled interfaces of the fitting engaging portions and the
 converging portions of the passageway of the fitting, the sealing members
 have limited ability to expand axially and, thus, are restricted to
 expanding radially. Through radial expansion, the sealing members more
 tightly press against the cable and the fitting, and cause better sealing
 about the cable.
 With the structural arrangement of the subject invention, not only is a
 tight seal obtained about a cable, but also tight, redundant seals are
 defined at interfaces about the cable at a location, such as the point of
 entry into an enclosure. The arrangement advantageously may be fluid tight
 to limit the ingress of fluid about the cable into the location.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring to FIGS. 1-3, a cable sealing arrangement 10 is shown for forming
 a seal about a cable C. The sealing arrangement 10 generally includes a
 fitting 20, scaling members 40, and nuts 60.
 The fitting 10 includes a flange 22 from which preferably extend two
 protrusions 24 in generally opposite directions. Each protrusion 24
 defines a free protrusion end 26 spaced from the flange 22. A passageway
 28, which is preferably generally venturi-shaped, extends between and
 through the protrusion ends 26 to define a chamber 25 within each of the
 protrusions 24. The chambers 25 are in fluid communication. The preferred
 venturi-shape provides the passageway 28 with tapered converging portions
 30 that are end-to-end and that flare outwardly towards the protrusion
 ends 26. It is also preferred that the passageway 28 define a straight,
 generally constant cross-sectional portion 32 between the converging
 portions 30 so as to define clearance therebetween. Alternatively,
 although not shown, the converging portions 30 can be arranged in
 contiguous fashion such that there is no clearance between the converging
 portions 30.
 The flange 22 facilitates mounting the fitting 20 to a desired location. To
 further enhance the ability to mount the flange 22, and thus the fitting
 20, mounting holes 34 are formed therein. Further, to enable mounting of
 the nuts 60 onto the protrusions 24, it is preferred that the protrusions
 24 each have a threaded outer surface 36 extending from its respective
 protrusion end 26. It is also preferred that the threads of the two outer
 surfaces 36 be reversed so that reverse torques are required to mount the
 nuts 60 onto the fitting 20.
 The sealing members 40 are each unitarily formed from any resilient
 material known to those skilled in the art that may be used to form a seal
 in a fairly harsh and wet environment. Two of the sealing members 40 are
 used, whereby the number of sealing members corresponds to the number of
 protrusions 24.
 Each of the sealing members 40 is formed with two axial ends 42 and a
 channel 44 that extends between and through the ends 42. The channel 44 is
 sized to allow the passage therethrough of the cable C and can be formed
 to define varying degrees of clearance about the cable C, or interference.
 It should be noted that the sealing members 40 must be threaded onto the
 ends (not shown) of the cable C and slid the length thereof into position
 in the fitting 20; thus, an excessively tight fit between the sealing
 members 40 and the cable C will result in a strenuous effort in mounting
 the sealing members 40 in the sealing arrangement 10.
 Preferably, each of the sealing members 40 is formed with a tapered fitting
 engaging portion 46 and a tapered nut engaging, portion 48 respectively
 defined in proximity to the ends 42. It is preferred that the taper of the
 nut engaging portions 48 be greater than the taper of the fitting engaging
 portions 46. The difference in taper can be used to define a flat face,
 such as the annular face 50. The degree of taper of the fitting engaging
 portions 46 is preferably equal to the degree of taper of the converging
 portions 30. A constant cross-section portion 52 may be formed on each of
 the sealing members 40 on external portions thereof, disposed between the
 fitting engaging portion 46 and the nut engaging portion 48. Finally, an
 edge 54 of both of the sealing members 40 can be rounded, chamfered, or
 broken in other manners known to those skilled in the art, so as to avoid
 having a sharp right corner.
 The nuts 60 each have a first end 62, with a large opening 64 being defined
 therein, and a second end 66, with a small opening 68 being defined
 therein. A passage 70 extends between the first and second ends 62, 66 to
 communicate the large opening 64 with the small opening 68. The passage 70
 is partially threaded to define an inner threaded portion 72 formed to
 threadedly engage the threaded outer surface 36 of one of the protrusions
 24. Disposed between the second end 66 and the inner threaded portion 72
 is a smooth ramped compression surface 74 that has generally the same
 diameter as the inner threaded portion 72 and converges toward the small
 opening 68. The degree of taper of the compression surface 74 is
 preferably equal to the degree of taper of the nut engaging surfaces 48 of
 the sealing members 40.
 To reduce the possibility of the cable C fraying, it is preferred that
 straight portions 76 extend into the nuts 60 from the small openings 68,
 rather than sharp, thin edges be used to define the small openings 68.
 Additionally, in a preferred embodiment, the nuts 60 are externally each
 formed with a polygonal cross-section portion 78, such as a hexagonal
 cross-section, shaped to be engaged by a standard tool for tightening the
 respective nut, such as a wrench, and with a frustoconical portion 80
 about the small opening 68. Although not shown, as an alternative, the
 frustoconical portion 80 may be formed hemispherically. The frustoconical
 portion 80 beneficially eliminates the formation of an outwardly facing
 right angle that may damage the cable C.
 Referring to FIG. 4, the sealing arrangement 10 is used in a location where
 the ingress of fluid is a concern, such as an enclosure E. The sealing
 arrangement 10 limits the ingress of fluid from the open atmosphere A,
 external of the enclosure E, to the interior I of the enclosure E, about
 the cable C. In use, the fitting 20 is mounted to the enclosure E using
 the flange 22. Thereafter, it is preferred that the cable C be fed through
 the passageway 28, and, the sealing members 40 be slid down the length of
 the cable C with the cable C being seated within the channels 44. The
 sealing members 40 are slid into contact with the converging portions 30
 of the fitting 20 such that the sealing members 40 are at least partially
 disposed within the protrusions 24. Additionally, the channels 44 are in
 fluid communication and, preferably, generally coaxially aligned in the
 arrangement.
 The nuts 60 are also threaded over the cable C and caused to come into
 threaded engagement with the protrusions 24 as shown in FIG. 4. With the
 nuts 60 mounted onto the fitting 20, the compression surfaces 74
 preferably come into contact with the nut engaging portions 48. Since the
 compression surfaces 74 are in bearing contact with the nut engaging
 portions 48, the chambers 25 are constricted upon tightening the nuts 60
 onto the fitting 20 (thereby causing translation of the nuts 60 towards
 the flange 22), and the sealing members 40 are caused to be compressed.
 With the sealing members 40 being disposed end-to-end, the sealing members
 40 may be in abutting contact. Due to the abutting contact and/or since
 the sealing members 40 define angled interfaces with the converging
 portions 30, axial elongation of the sealing members 40 due to compression
 is limited. Accordingly, the applied compressive forces cause radial
 distortion of the sealing members 40. To illustrate this point, dashed
 lines in FIG. 4 represent an uncompressed state of the sealing members 40,
 wherein the sealing members 40 are longer in length and smaller in
 cross-sectional thickness. Upon being compressed, the sealing members 40
 are foreshortened and caused to have larger cross-sections.
 Advantageously, the increase in cross-section translates to a reduction in
 size in at least portions of the channels 44. In other words, diameter D
 of the channels is reduced under compression, thus causing the sealing
 members 40 to more tightly press against the cable C and define a better
 seal. Also, the sealing members 40 press more tightly against the fitting
 20. The tight pressing may define fluid tight seals about the cable C.
 In addition, preferably the fitting engaging portions 46 define sealing
 interfaces with the converging portions 30, whereas, the nut engaging
 portions 48 define sealing interfaces with the compression surfaces 74.
 All told, at least four redundant sealing interfaces are formed about the
 cable C in addition to the tight engagement of the cable C by the sealing
 members 40. Depending also on the extent of compression, the annular faces
 50 may define sealing interfaces with the protrusion ends 26.
 FIG. 5 depicts a second embodiment of the invention, wherein the sealing
 members 40 are not formed with tapered nut engaging portions 48, and the
 nuts 60 are not formed with compression surfaces 74. Rather, the first
 ends 66 of the nuts 60 directly engage ends 42 of the sealing members 40
 in causing compression thereof. Here, the first ends 66 and the ends 42
 define sealing interfaces.
 Thus, while there have been shown and described and pointed out fundamental
 novel features of the invention as applied to preferred embodiments
 thereof, it will be understood that various omissions and substitutions
 and changes in the form and details of the disclosed invention may be made
 by those skilled in the art without departing from the spirit of the
 invention. It is the intention, therefore, to be limited only as indicated
 by the scope of the claims appended hereto.