The present invention relates to cable enclosures, and in particular to end caps or seals that provide a sealing relationship between cables and the enclosure. The invention particularly concerns end seals used with cable assemblies having non-circular transverse cross-sections.
Cables, such as telecommunication cables, carry hundreds and sometimes thousands of insulated wires or optical fibers. Such cables are often used aerially and extend between supports above the ground. Aerial cables may be extended between supports such as poles by stringing a support wire (i.e., a “messenger”) in a catenary between two poles and then lashing a multi-conductor cable or fiber optic cable (single or ribbon fiber) to the messenger. When two or more cable ends are joined together, as when tapping into an extended length of cable, a splice is created. Generally, the splice is enclosed for protection from the environment, including protection against weather elements, animals, insects and so forth.
Structures adapted for enclosing portions of cables are frequently referred to as splice closures or, more generally, cable closures. Such closures are typically adapted to enclose therein at least two and sometimes more cable ends. As used herein, the term “cable end” and variants thereof refer to a portion of a cable having exposed telecommunication lines (i.e. connective wires or optical fibers) and any additional connecting devices involved. Cable closures generally comprise a re-enterable compartment or casing having first and second opposite ends. The casing may be elongate to enclose a length of the cable, and may have a cross-sectional shape that is cylindrical or any other suitable shape. Cables to be joined are directed into the casing through the end walls of the casing. At each of the casing end walls, sealing means are generally required to ensure an environmental seal around the cables (i.e., between the cables and the cable closure).
Generally, a plurality of features are desirable in a sealing system used in association with cable closure end walls. Generally, the seal system should be configured such that it can be readily mounted around, or removed from association with, a continuous cable. Due to its extended length, a cable often cannot be easily threaded through an aperture, and the seal system is therefore desirably adapted for mounting about a mid-portion of an already positioned cable. In addition, the seal system should be capable of accommodating a variety of sizes of cables to reduce the number and type of seals which must be kept in inventory.
Existing end seals have been developed for use with cables having substantially round or circular transverse cross-sectional shapes, which are relatively easy to seal. However, cables having non-circular transverse cross-sectional shapes are increasingly being used. In particular, there is a trend toward the use of self-supporting aerial cables. Self-supporting cables are reinforced with internal strength members to support their own weight, such that the cable can be installed in an aerial environment without the use of a messenger. One type of self-supporting cable is a so-called Figure-8 cables. Figure-8 cables are cables in which a messenger is run parallel with and adjacent to a cable core within a common plastic jacket which encloses both the core and the messenger wire. The transverse cross-sectional shape of the cable generally resembles a figure-8 shape, with the messenger portion of the cable forming one lobe, and the core portion of the cable forming another lobe. Figure-8 cables can be attached to supports by splitting the messenger from the cable and attaching the messenger with clamps and dead ends as with a normal steel messenger.
Sealing around a self-supporting cable such as a Figure-8 cable is difficult due to the transverse cross-sectional shape of the cable. In addition, cables having various combinations of cable core portion diameters and messenger portion diameters are available, making it difficult to provide a single solution meeting the requirements of many different cable sizes. Current solutions for sealing Figure-8 cables generally involve wrapping tape around the cable. Tape may be wrapped around the cable until a generally circular cross-section is achieved, such that sealing members intended for round cables may be used. Mastic tapes may be wrapped around the cable to fill gaps between the cable and the closure. However, use of tapes and the like is not convenient for field installation, and greatly increases the time required to complete the installation. In addition, every time the closure is re-entered, the old tape must be removed and new tape installed, thereby increasing the cost of reentry operations.
One aspect of the invention described herein provides an end cap for sealing an end of a closure about a cable member directed therein. In one embodiment according to the invention, the end cap comprises a wall member having a first surface, a second surface and an outer circumferential edge. A longitudinal port extends through the wall member from the first surface to the second surface. The port has a transverse cross-sectional shape defined by first and second lobed portions joined at a waist, the cross-sectional shape configured for receiving a cable assembly having a corresponding transverse cross-section therethrough.
Another aspect of the invention described herein provides an enclosure for a telecommunication cable having a plurality of telecommunication lines. In one embodiment according to the invention, the enclosure comprises a re-enterable compartment for retaining telecommunication line connection devices, the re-enterable compartment including an opening for receiving a telecommunication cable assembly. A sealing member is configured for forming a seal between the telecommunication cable assembly and the compartment opening. The sealing member comprises a wall member having a first surface, a second surface, and an outer circumferential edge configured to sealingly engage the compartment opening. A longitudinal port extends through the wall member from the first surface to the second surface. The port has a transverse cross-sectional shape defined by first and second lobed portions joined at a waist, the cross-sectional shape configured for receiving the cable assembly therethrough.
The present invention will be further described with reference to the accompanying drawings wherein like reference numerals refer to like parts in the several views, and wherein:
In the following Detailed Description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
Referring now to
Still referring to
Alternatively, the end cap 30 can be used in conjunction with a figure-8 conduit. An exemplary figure-8 shaped conduit is commercially available (Silicore™ Figure-8 Self-Support Duct,Agents Private International Ltd., Ontario Canada or STRAND-GUARD® Flexcor Flexible Corrugated Aerial Figure-8 Conduit, ARNCO® Corporation, Elyria, Ohio). For example,
One exemplary embodiment of end cap 30 is illustrated in greater detail in
End caps 30 according to the invention are not integrally formed with casing 12. That is, end caps 30 are generally removable from casing 12 and replaceable therein. An advantage to this is that an end cap 30 configuration appropriate for the particular installation (e.g., a configuration accommodating the desired number, shapes and/or sizes of cables passing therethrough) may be selected. Generally, end caps 30 according to the present invention can be formed in a single or two piece construction from a relatively soft rubber material, or a highly rubberized material. The materials forming end caps 30 are preferably capable of flexing and deforming under stress during use, such as to accommodate variations in size of the cables, or to accommodate movement of the cables relative to one another without substantial loss of seal. In one embodiment, the material forming end caps 30 is a thermoplastic rubber having a durometer not less than 40 Shore A hardness. One suitable thermoplastic rubber material is available from Advanced Elastomer Systems (AES) an affiliate of Exxon Mobil Corporation and sold under the trade designation Santoprene.
Referring to
In the illustrated embodiment, end cap 30 further includes second, third and fourth longitudinal ports 50, 52, 54, extending through wall member 32. As best seen in
In use, ports 40, 50, 52, 54 extend completely through end cap 30 for passage of cables 26, 28 therethrough. When end cap 30 is constructed, however, ports 40, 50, 52, 54 may be blocked or occluded by relatively thin pieces of material which are easily cut out to open the port. Additionally, the cut away region can be configured such that it is possible to select the size of the port created based on the size of cable which is to be inserted therethrough. Alternatively, the ports can be configured to accommodate a single cable construction. It will be understood that various numbers of ports may extend through end cap 30 according to the present invention, and that alternate arrangements of ports may be utilized in various applications.
In one embodiment, end caps 30 of the present invention are configured for mounting in casing 12 in such a manner that end caps 30 are properly positioned within casing 12 (e.g., first lobed portion 42 of port 40 is oriented toward the top of casing 12, such that splice closure 10 hangs from messenger portion 26a of cable 26 extending therethrough). In one embodiment, end caps 30 are retained in position within casing 12 even when casing 12 is opened along seam 14. Referring to
As best seen in
Interior wall section 60 includes outer face 66 and inner face 67, while exterior wall section 62 includes outer face 68 and inner face 69. Outer face 66 of interior wall section 60 defines first surface 34 of wall member 32, and outer face 68 of exterior wall section 62 defines second surface 36 of wall member 32. Inner face 67 of interior wall section 60 and inner face 69 of exterior wall section 62 are positioned adjacent each other along interface 64. Interior wall section 60 and exterior wall section 62 include corresponding interior and exterior portions of ports 40, 50, 52, 54. Specifically, interior wall section 60 includes interior port portions 40a, 50a, 52a, 54a; while exterior wall section 62 includes exterior port portions 40b, 50b, 52b, 54b. The terms “inner” and “outer” when used with respect to faces of interior and exterior wall sections 60, 62 generally refer to whether the face is directed toward a mating section 60, 62 or away from a mating section 60, 62 during use. The terms “inner” and “outer” as used herein are meant only to refer to relative positions and/or orientations for convenience, and are not to be understood to be in any manner otherwise limiting.
In some installations, end seals 30 may be positioned close to a cut cable end, such that end cap 30 may be installed on the cable by threading the cut end of the cable through a selected one of ports 40, 50, 52, 54. In other installations, end seals 30 may not be positioned close enough to a cut cable end to permit threading the cable end through a port. For installations away from a cut cable end, selectively openable entrance slits 70 are provided to allow installation of cables into ports 40, 50, 52, 54. Selectively openable entrance slits 70 may initially be held closed by a relatively thin web of material, such that slits 70 define cut lines that may be selectively cut open by a knife, scissors or the like. Opened entrance slits 70 may be spread open or twisted to fit around a cable as the cable is introduced into a corresponding port.
Referring now to
Referring to
Other means may be provided to facilitate mating and alignment of interior and exterior wall sections 60, 62. For example, a pin and aperture arrangement may be formed along interface 64. In one embodiment, one or more pins 72 are formed on inner face 67 of interior wall section 60, and corresponding recesses 74 are formed on inner face 69 of exterior wall section 62.
Referring now to
In one embodiment, and as best seen if
In one embodiment, transverse skirts 86a, 86b and flexible sealing lips 82a, 82b, respectively, are circumferentially aligned with each other. To provide improved dimensional range and flexibility of both sealing lips 82 and skirts 86 sealing lips 82 and skirts 86 may be longitudinally offset, relative to the plane of wall 32. In one embodiment, flexible sealing lips 82 and skirts 86 are both angularly inclined relative to the plane of wall 32. Sealing lips 82 and skirts 86 may be inclined in the same or opposite directions.
As best seen in
In the illustrated embodiment, port portion 40a extending from exterior wall section 62 includes elongate member 84′ (
Referring now to
In use, end cap 30 is installed on self-supporting cable 26 by first opening entrance slits 70a, 70b of interior and exterior wall sections 60, 62, respectively, that extend into port 40. If port 40 is configured to accept different sizes of self-supporting cables 26, material may be removed from port 40 to obtain the desired port size. Self-supporting cable 26 is then passed through opened slits 70a, 70b into port 40. A cable tie or the like is optionally installed over elongate member 84 adjacent second surface 36 to aid in sealing against the surface of cable 26 as well as providing strain relief for cable 26. If one or more distribution cables 28 are to be installed, ports 50, 52, 54 are opened as needed by cutting appropriate entrance slits 70a, 70b and/or removing material to obtain the desired port diameter(s). Distribution cables 28 are then installed in one or more opened ports 50, 52, 54. Interior wall section 60 and exterior wall section 62 are mated and the assembled end cap 30 is installed in recess 59 of casing 12, using mounting tabs 56a, 56b as described above. These operations are completed for each end 22, 24 of closure 10, after which the installation is finished.
To re-enter closure 10, such as to install an additional distribution cable 28, it is only necessary to open closure 10 along seam 14, pull the end seals 30 with cables 26, 28 therethrough from casing 12. Interior and exterior wall sections 60, 62 are removed from the cables 26, 28, new cuts into ports 50, 52, 54 are opened as needed, and the end seals 30 are re-installed as described above. The end seals 30 are re-used, and the only additional material that may be required are one or two cable ties.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
Number | Date | Country | Kind |
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200610095928.8 | Jun 2006 | CN | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2006/026289 | 7/7/2006 | WO | 00 | 11/26/2008 |