Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of the earlier filing date of U.S. Provisional Patent Application No. 62/186,605 filed on Jun. 30, 2015, the disclosure of which is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of this invention relate generally to methods and apparatus for sealably joining cables to other devices for use in harsh environments such as seawater. 
       BACKGROUND OF THE INVENTION 
       [0003]    There are a great many harsh environment applications in which cables carrying electrical and/or fiber-optical conductors are used to network submersible devices such as pumps, motors, and environmental sensors. In these applications, the cables are usually either terminated directly to the devices, or are terminated to connectors which then connect to the devices. 
         [0004]    The term “cable termination” as used herein consists of the union between a cable&#39;s conductive elements and the respective conductive elements of a connector or other appliance to which the cable is attached. For convenience the part to which the cable is joined will hereinafter simply be called a “connector” with the understanding that it could be any sort of device. In harsh environments such as that found in sewers, ponds, or in seawater, for example, cable terminations are used to attach waterproof cables to submersible connectors. 
         [0005]    The most widely used type of harsh-environment electrical cable termination consists of a cable-connector junction over-molded with a resilient material such as neoprene, polyurethane, or polyethylene. The over-mold renders the union impermeable to the exterior environment and protects it from mechanical damage. Over-molded terminations have the disadvantages that they must be made in a clean, controlled laboratory environment and require specialized chemicals, molds and other equipment. Under some conditions molded terminations also suffer from de-lamination of the bonds that bind and seal them to the other components. Representative examples of such terminations can be found in the open literature of major underwater connector manufacturers such as Seacon, Teledyne Impulse, Kemlon, and several others. Over-molded terminations generally represent old art. 
         [0006]    A second sort of harsh environment electrical termination is completely mechanical, relying on layered elastomeric seals to protect the conductor junctions. Representative examples of this sort of termination are found in U.S. Pat. Nos. 7,182,617, and 7,690,936. This type of termination is field installable and repairable without specialized equipment; however, its use is restricted to very light-duty operations because there are no provisions to keep cable torque, bending, compression, or tension from working directly on the conductor junctions. 
         [0007]    Another, more robust, type of harsh-environment cable termination houses the joined conductive elements of the cable and connector in a pressure-compensated chamber that is filled with a mobile substance. These terminations are installable and repairable in the field without the need of chemicals, molds or other specialized appliances. Pressure compensating the terminations relieves much of the stress on the conductor junctions, and reduces the possibility of environmental fluid intruding into the termination. Historically the mobile substance used in these terminations has been a dielectric grease, gel, or oil. More recently, lubricious powders have been proposed as the mobile substance, as in U.S. Pat. Nos. 9,116,323 and 8,899,841. For convenience in this document the mobile substance will simply be called fluid or oil, with the understanding that it could be any suitable material that remains mobile over the termination&#39;s entire operating ranges of lifetime, temperature and pressure. Typical examples of prior art fluid-filled terminations are disclosed in U.S. Pat. Nos. 3,877,775, 4,039,242, 4,673,231, 4,940,416, 6,796,821, 7,182,617, 7,429,193 and 7,614,894, and in foreign patent EP2252442. A cursory review of fluid-filled termination prior art reveals its ubiquitous complexity. 
         [0008]    Components commonly used in oil-filled cable terminations include a flexible portion of the compensation chamber&#39;s wall that allows the chamber to adjust for volume and pressure changes. In terminations wherein the bitter ends of cables enter the oil-filled compensation chamber, breakout boot seals are often used to seal the interfaces where individual conductors issue from the cable&#39;s end. In addition to providing an isolative layer around otherwise exposed portions of electrical conductors, boot seals are intended to keep the chamber oil from escaping into the cable&#39;s interstices. Such oil loss can quickly lead to chamber collapse and catastrophic termination failure. As discussed in U.S. Pat. No. 6,796,821, prior art elastomeric breakout boot seals are easily displaced from their sealing positions, particularly in applications wherein there is rough handling or an overpressure of mobile material within the cable itself that might extrude into the boot seal and push it out of sealing engagement or even completely off of the cable&#39;s end. 
         [0009]    There remains a need for a fluid-filled termination whose breakout boot seals remain in sealing position on the cable end to which they are installed, even in the case where there is an unseating overpressure within the cable itself. 
         [0010]    The invention disclosed herein is a field-installable, removable, and repairable cable termination of the fluid-filled type. It integrates a breakout boot seal and a flexible-walled fluid chamber enclosure into a unified component, thereby yielding an assembly which is much simpler than prior art terminations. The assembly includes a pressure relief feature which vents any mobile material extruded from the cable&#39;s end into the outside environment, and not into the compensation oil chamber. It also includes two unique methods for managing optical fibers within the termination. The disclosed embodiments are for a simple unarmored marine cable-to-connector termination, but it will be obvious to those familiar with the art that it can equally well be adapted for more complex applications such as for armored cables. The invention should find use in a wide variety of applications wherein the high reliability of fluid-filled, field-installable and repairable terminations is required. 
       SUMMARY OF THE INVENTION 
       [0011]    A harsh environment cable termination is provided which can be installed, tested, and if necessary, repaired in the field prior to submersion. The invention is described as a simple assembly that sealably joins one cable to one underwater connector. Although the invention is disclosed in that simple arrangement, it will be clear that it can be configured for joining a wide variety, size, and number of diverse components. 
         [0012]    In the invented termination the cable is mechanically attached to the connector by way of a grip in the rear portion of an elongated shell, which shell, in turn, is mechanically attached on its forward end to a connector body. The shell forms a protective barrier for the more vulnerable portions of the termination contained within it. A flexible-walled fluid-filled chamber encloses the union between a cable&#39;s electrical and/or optical fiber conductive elements and the respective conductive elements of the connector. The chamber&#39;s flexible walled enclosure is exposed to the in-situ environment, allowing the fluid pressure within the chamber to change with changing outside pressure, and to volumetrically expand or contract due to temperature and pressure changes. A cable-end breakout boot seal is integrally formed as part of the flexible-walled chamber enclosure, thereby greatly simplifying the architecture of the termination. The breakout boot seal is kept in place by a positive mechanism that retains it on the cable&#39;s end. The unified chamber enclosure and breakout boot seal structure includes a pressure relief feature that vents cable internal overpressure to the outside environment. The device is quickly and easily installable, and if necessary, removable and reparable in the field with no special training or tools. At the same time, the integrated chamber enclosure and breakout boot seal eliminate some of the potential leak paths and other failure modes inherent in more complex prior-art terminations. The economy and ease of installation, without need of laboratory conditions, should favor the use of the invention over traditional over-molded terminations in a wide variety of applications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The details of the invention, both as to its structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
           [0014]      FIG. 1  illustrates a prior art breakout boot seal. 
           [0015]      FIG. 2  is an oblique view of the invented termination joining an underwater connector  2  on one end, and a simple unarmored cable on the other end. 
           [0016]      FIG. 3  is a partially sectioned axial view of the termination assembly of  FIG. 1 . 
           [0017]      FIG. 4  is an exploded view of the termination assembly of  FIG. 1 . 
           [0018]      FIG. 5  illustrates a retaining device. 
           [0019]      FIG. 6  illustrates a cable grip. 
           [0020]      FIG. 7  depicts a boot seal removal tool. 
           [0021]      FIG. 8  shows the construction of a typical subsea cable. 
           [0022]      FIG. 9  is a partially sectioned axial view of an alternative embodiment of the termination assembly shown in  FIG. 3 . 
           [0023]      FIG. 10  is a standoff device. 
           [0024]      FIG. 11  is a view of isolated components showing an optical fiber managed in a flat coil. 
           [0025]      FIG. 12  illustrates a clip for managing optical fibers within the termination. 
           [0026]      FIG. 13  is an external view of the unified chamber housing showing ventilation ribs. 
           [0027]      FIG. 14  is a view of isolated components showing an optical fiber managed in a curved coil. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    Co-pending U.S. Patent Application 62/156,371 entitled “Boot Seal,” is incorporated herein by reference. A typical prior-art cable-end, elastomeric, breakout boot seal is shown in  FIG. 1 . It consists of a sleeve portion  200  which is constrictively stretched over the end of cable  3 . The environmental fluid pressure P f  has the effect of unseating the rear portion of sleeve  200 ; however, there is a pressure P f +P s , where P s  is the “stretch” pressure of the constrictive elastomer upon cable  3 . The stretch pressure works in cooperation with the environmental pressure to keep the sleeve seated. Since (P f +P s )≧P f  in all cases, the rearward portion of sleeve  200  will not be unseated by environmental fluid pressure P f , and the seal will not fail in that mode no matter how great the environmental fluid pressure. The same reasoning is true for all elastomeric boot seals wherein there is adequate stretch to conformably seat the sealing sleeve to the object over which it is stretched. 
         [0029]    Individual sleeves  290 , which are integrally molded onto heavy end-wall  295  of sleeve  200 , stretch over individual cable jacketed conductors  300 . The same mechanism that worked to keep the interface between sleeve  200  and cable  3  sealed, keeps the interfaces between sleeves  290  and conductor jackets  300  sealed; that is, (P f +P s1 )≧P f , where P s1  is the stretch pressure that constrictive sleeves  290  exert on respective conductors  300 . It is therefore clear that no matter how great fluid pressure P f  is, the various interfaces will remain sealed against it. 
         [0030]    As discussed in U.S. Pat. No. 6,796,821, prior art elastomeric breakout boot seals like that shown in  FIG. 1  can be easily displaced and unseated, particularly if there is an overpressure within cable  3  to which they are attached. Looking still at  FIG. 1 , it is clear that if appreciable pressure developed within cable  3 , as might occur from out-gassing of material within cable  3 , for instance, the  FIG. 1  boot seal would simply be pushed off of the end of cable  3 . Such cases are more likely when the opposing environmental fluid pressure P f  is small. In the case of subsea cables, that means either when the cable is not yet submerged, or when it is in shallow water. There are process-type breakout boot seals, such as those manufactured by Tyco-Raychem, which sealably adhere to the cable, and are not as easily displaced. But using process-type boot seals is not always practical; for instance, when the cable jacket cannot be adhered to, or when the seal must be installed in conditions detrimental to the sealing process. 
         [0031]    The invented termination is disclosed herein in two embodiments, both of which utilize breakout boot seals that are retained in place on the ends of the cables onto which they are installed. The first embodiment incorporates a breakout boot seal construction as disclosed in co-pending U.S. Patent Application 62/156,371. In the &#39;371 construction the breakout boot seal includes a mechanism that grips directly onto the cable being terminated. The second embodiment does not grip directly onto the cable; instead, it is retained by standoff-rods that cooperate with one retainer washer external to the breakout boot seal, and another washer internal to the breakout boot seal. 
       First Embodiment 
       [0032]      FIG. 2  is an overall oblique view of invented termination  2  used to join connector  1  to cable  3 , and  FIG. 3  is a partially sectioned view of the assembly shown in  FIG. 2 .  FIG. 4  is a partially sectioned exploded view of the assembly shown in  FIG. 2 . 
         [0033]    Looking now at  FIGS. 3 and 4 , underwater connector  1  is mechanically joined to the forward end of termination shell  4  by spring pins  5   a  and  5   b . Pins  5   a  and  5   b  seat in respective through holes  6   a  and  6   b  in termination shell  4 , and in respective slots  7   a  and  7   b  in connector back shell  8 , thereby both rotationally and axially locking termination shell  4  to connector  1 . Cable  3  passes into the rearward portion of termination shell  4  through cable grip assembly  9 . Connector  1 , shell  4 , and grip assembly  9  altogether form the termination&#39;s protective housing. Shell  4  may be made of any substantially rigid material such as hard plastic or metal that is suitably rugged for the intended application. 
         [0034]    Cable grip assembly  9  comprises retainer nut  10 , washer  11  and cable grip  12 . Cable grip  12  may be made of a hard but somewhat flexible material such as Ryton® PPS (polyphenylene sulfide). Threads  13  on retainer nut  10  cooperate with threads  14  in the rearward end of termination shell  4  to contain cable grip assembly  9  within conical bore  15   a  of termination shell  4 . Retainer nut  10  has an oversized through bore  10   a  which is slightly larger than the outer diameter of cable  3 , and therefore does not seal to cable  3 . Tightening retainer nut  10  tightly presses the elements comprising cable grip assembly  9  into conical bore  15   a  of inner diameter  15  of termination shell  4 , forcing the exterior conical surface of cable grip  12  axially into conical bore  15   a.  A roughened exterior surface  16  of cable grip  12  ( FIG. 6 ) is forced against roughened surface (not shown) of conical bore portion  15   a  of termination shell  4  to rotationally lock cable grip assembly  9  to termination shell  4 . Cable grip  12  is split through axially by slot  17 , causing it to compress radially when forced axially inward against conical bore  15   a.  Cable grip  12  is also partially segmented into individual tines  18  separated by slots  19  which facilitate its radially inward compression, and which cause radial ridges  20  to bite into the exterior of cable  3  thereby gripping cable  3 . No element of cable grip assembly  9  seals against cable  3 ; instead, in-situ environmental fluid is free to flow through it into and out of the interior of termination shell  4 . 
         [0035]    One advantage of the invention is that all of the elastic portions enclosing fluid chamber  21  are integrated into a single unified part: chamber enclosure  22  ( FIG. 13 ). Depending on the particular application, chamber enclosure  22  may be made of an elastomer which is chemical compatible with the other elements of the termination with which it is in contact. In some cases neoprene would be acceptable, for instance, or natural rubber. Fluid chamber  21  is defined by chamber enclosure  22 , connector  1  and cable  3  as follows: The forward end of fluid chamber  21  is closed by the (hidden) rear wall of connector  1 . Inward facing shoulder  23  of chamber enclosure  22  seals into seat  24  of connector  1 . Shoulder  23  is held sealable into seat  24  by inner wall  25  of termination shell  4 . Generally tubular wall  26  of chamber enclosure  22  housing fluid  27  extends backward from inward facing shoulder  23  into heavy walled portion  28   a  of integrally molded breakout boot seal portion  28 . Breakout boot seal sleeves  29  sealably stretch over jacketed conductors  30 . Other boot seals  31  sealably stretch over the terminal ends of jacketed conductors  30  and over boot seal nipples  32  of connector  1 . Sleeves  33  and  34  extend back along cable  3  from end wall  35  of boot seal portion  28  thereby completely enclosing fluid chamber  21 . Fluid chamber  21  is thus defined and sealed. 
         [0036]    Note that cable  3  does not enter fluid chamber  21 ; only the individual jacketed conductors  30  enter fluid  27  within fluid chamber  21 . Space  36  surrounding the outside of chamber enclosure  22  and inside of termination shell  4  is open to the in situ environment, for instance seawater, which is free to pass through cable grip assembly  9  and thence through the space between inner diameter  15  of shell  4  and the outer diameter of sleeve  34 . Ventilation through cable grip assembly  9  takes place by way of axial slots  17  and  19  of cable grip  12  and the oversized central bore  10   a  of retainer nut  10 . Means other than the ventilation through cable grip assembly  9  can be provided if needed; for example, one or more vent holes  37  could be added. Tubular wall  26  of chamber enclosure  22  allows changes of the in-situ environmental pressure outside of chamber enclosure  22  to be transmitted to fluid  27  as the in-situ pressure increases and decreases. 
         [0037]    Although more than one way can be envisioned for retaining breakout boot seal portion  28  of chamber enclosure  22  in place on the end of cable  3 , in the first described embodiment it is accomplished by a retainer  38  in the form of a push-nut type fastener, shown also in  FIG. 5 , which is integrally molded or inserted into thick-walled portion  28   a  of boot seal portion  28  of chamber enclosure  22 . Post-mold insertion of retainer  38  is possible due to the elasticity of boot seal portion  28 . Retainer  38  can be made from rigid flexible material such as thin metal or hard plastic which keeps boot seal portion  28  in place on cable  3 . Retainer  38  does not rely on bonding or any other chemical processes. Push-nut fasteners such as retainer  38  are widely available commercially, for instance from ARaymond Tinnerman. 
         [0038]    Referring to  FIG. 5 , retainer  38  includes a circular peripheral body  39 . Extending axially through body  39  is a central opening  40 . Opening  40  has a generally circular configuration and has an inner marginal periphery that is defined by a plurality of individual tab-like extensions or tines  41 . The tines  41  are inclined radially inwardly from body  39  and cooperate to define a conical shape about the margin of opening  40 . Tines  41  are separated from one another by recesses  42 . Note that recesses  42  represent openings that keep retainer  38  from sealing to the outside surface of cable  3 . Referring now to  FIG. 3 , the distal ends of tines  41  of retainer  38  forming opening  40  are disposed at a diameter which is less than the inner diameter  43  of heavy walled portion  28   a  of boot seal portion  28 , and somewhat less than the outer diameter of cable  3 . Inner diameter  43 , in turn, is greater than the outer diameter of cable  3  thereby allowing distal tines  41  to project inward from inner diameter  43  to effectively grip cable  3 . 
         [0039]    There&#39;s another advantage to having inner diameter  43  of boot seal portion  28  slightly larger than the outer diameter of cable  3 . It is that sleeve portion  33  does not constrictively seal to cable  3  along inner diameter  43 . As an added measure to ensure that sleeve  33  does not seal to cable  3  along inner diameter  43  of boot seal portion  28 , axial ribs (not shown) along inner diameter  43  can be provided. Ventilation between inner diameter  43  of boot seal portion  28  and the outer surface of cable  3  is important, because, as will soon be discussed, it provides that any material issuing from the end of cable  3  due to an overpressure within the cable can be made to migrate to sleeve  34  of boot seal portion  28  where it will subsequently be discharged. 
         [0040]    The main function of retainer  38  is to keep chamber enclosure  22  in place on the end of cable  3 . Retainer  38  forms a one-way axial grip onto cable  3 , allowing cable  3  to be pressed through retainer  38  from the rearward end, but not to be subsequently withdrawn from it. Tines  41  on retainer  38  are angled forward, and can be deflected radially outward by the rearward entering cable. During assembly, retainer  38  permits chamber enclosure  22  to be pushed onto the end of cable  3 , with conductors  30  being fed through sleeves  29 . Once pushed into place on the end of cable  3 , retainer  38  keeps chamber enclosure  22  from subsequently being forced off of the end of cable  3 . 
         [0041]    If for some reason chamber enclosure  22  needs to be removed from cable  3 , a thin, split, flexible tube  50  such as shown in  FIG. 7  can be slid from the rear under both sleeve  34  and retainer  38  to displace tines  41  outwardly, freeing cable  3 . Tube  50  can be cut and rolled from suitable thin sheet material. 
         [0042]    Chamber enclosure  22  is formed with a relatively thin walled, tubular portion  26  which extends radially outward from thicker walled portion  28   a , and then extends forward in a generally tubular shape that terminates on its forward end in inward protruding shoulder  23 . Sleeve  33  extends forward of thicker-walled portion  28   a,  and terminates in a relatively thick end wall  35 . Sleeves  29  extend forward from end wall  35 , with the bores of sleeves  29  continuing rearward through wall  35 . Sleeve  34  of chamber  22  extends rearward constrictively over cable  3  from a point rearward of retainer  38 . 
         [0043]    Retainer  38  keeps breakout boot seal portion  28  of chamber enclosure  22  in place against modest pressure internal to cable  3 . Both the jacket of cable  3  and thicker walled portion  28   a  of boot seal portion  28  of chamber enclosure  22 , being of resilient material, have some limitations regarding the retaining ability of retainer  38 . The retaining ability can be enhanced by having multiple retainers  38  spaced axially along cable  3 , but it still will be limited. The retention of boot seal portion  28  of chamber enclosure  22  onto the end of cable  3  can also be enhanced by relieving any cable  3  internal overpressure at a low level. 
         [0044]    To better understand internal cable pressure, consider  FIG. 8  which shows one typical sort of underwater cable construction. It consists of outer cable jacket  60  and inner jacketed conductors  30 . The space  61  between jacketed conductors  30  and outer cable jacket  60  contains a filler  62  which may or may not be porous. In any case, pressure can build up along the interfaces between jacketed conductors  30  and filler  62 , and/or within the interface between outer cable jacket  60  and the filler  62 , and in the case of a porous filler, within filler  62  itself. Said more succinctly, pressure can possibly build up anywhere within space  61  between jacketed conductors  30  and outer cable jacket  60 . The internal pressure within cable  3  may increase due to a variety of mechanisms. For example, the plastic jackets of jacketed conductors  30  within cable  3  can continue to outgas as they age, thus creating an internal pressure inside cable  3 ; or mobile substances such as gel fillers or intruded water can migrate within cable  3  due to handling, also potentially increasing pressure in cable  3  within space  61 . When the internal cable pressure exceeds a desired level, it is advisable to provide a release path to relieve the pressure without damaging or unseating boot seal portion  28  from cable  3 . 
         [0045]    In general, when the overpressure internal to a boot seal sleeve reaches a certain level it causes the boot seal sleeve to expand radially, allowing gas or fluid inside of it to leak outward along the interface between it and the object over which it is stretched; however, environmental fluid will still not leak in. Boot seal sleeves make effective one-way pressure relief valves, for which they are frequently used. 
         [0046]    Referring now to  FIG. 3 , in fluid-filled cable terminations any cable  3  internal overpressure should be relieved rearwardly along the external surface of cable  3  through the interface  70  between cable  3  and sleeve  34 , and not forwardly into fluid chamber  21 . That can be accomplished by designing the stretch pressure of boot seal sleeve  34  on cable  3  to be much less than that which any of boot seal sleeves  29  exert on the jacketed conductors  30  over which they are constrictively stretched. In that case, any material forced outward from the cable  3  interior will pass out under sleeve  34  via path  70  and thence into the external environment, and not into fluid chamber  21 . 
         [0047]    One simple way to control the stretch pressure on any elastomeric sleeve is by increasing or decreasing its wall thickness and/or inner diameter. Thicker walls and/or smaller inner diameter sleeves exert more stretch pressure on the objects over which they are stretched, and thinner wall thicknesses and/or larger internal sleeve diameters exert less stretch pressure. 
         [0048]    In pressure-balanced fluid-filled terminations it is typically assumed that the fluid pressure within the chamber is approximately equal to the pressure outside of the chamber due to the easy transmission of the outside pressure to the fill fluid. The discussion is always couched in terms of the pressure within the fluid chamber adjusting to the external in-situ pressure. It is not discussed in terms of the outside environmental pressure adjusting to the pressure in the fluid chamber, because that cannot happen; the outside environment is of infinite volume for all practical purposes. 
         [0049]    However, there are some non-trivial cases in which the pressure within the chamber can exceed the outside environmental pressure. For instance, there is nearly always some air left in the fluid chamber during assembly. Subsequently the entrapped air can expand in the case where the in-situ pressure is relatively low, such as when a fluid-filled termination is transported at high altitude, or when it&#39;s exposed to high temperatures. In a termination having no means to contain expansion of its compensation chamber, the pressurized entrapped air could displace the compensation chamber enclosure out of sealing position; or worse, it could rupture the chamber enclosure out through the vent passages found in most prior art terminations. 
         [0050]    The invented termination is designed to prevent those potential failures. Over-pressure within chamber enclosure  22  will cause chamber enclosure  22  to expand to fill the large diameter, rear, bell shaped portion  71  of termination shell  4 , which keeps chamber enclosure  22  from expanding further. There are no vent holes in shell  4  that are positioned in such a way that the walls of chamber enclosure  22  could extrude and rupture through them. Pressure from the expanding air will force heavy-walled portion  28   a  of chamber enclosure  22  against end wall  52  of termination shell  2 . Note that the outer diameter of retainer  38  is greater than the rearward inner diameter  15  of termination shell  4 . Rearward expansion of chamber enclosure  22  is thus arrested by the interference of retainer  38  and end wall  52 . The expansion of chamber  21  is therefore limited in every direction rendering it undamaged and in place in the presence of over-pressure within fluid chamber  21 . 
         [0051]    Ribs  72  seen in  FIG. 13  on the rearward bell-shaped wall  73  of chamber enclosure  22  guarantee that rear exterior wall  73  of chamber enclosure  22  will not seal to rear wall  52  of termination shell  4  when pressed against it. Ventilation between space  36  exterior to tubular portion  26  of chamber enclosure  22  and the external environment takes place along the ribbed portion of exterior wall  73 , thence through the space between the outside diameter of sleeve  34  and inner diameter  15  of shell  4 , and onward through slots  17 ,  19  of cable grip  12  and finally through the oversized bore  10   a  of retainer nut  10 . 
         [0052]    The procedure for installing the termination is easily understood from  FIG. 4 . Nut  10 , washer  11 , cable grip  12  and termination shell  4  are slid backward onto cable  3  in the order shown. The end of cable  3  is prepared by cutting back the outer jacket and filler material to expose lengths of jacketed conductors  30 . If not already molded in place, retainer  38  is inserted into chamber enclosure  22 . Slight lubrication of the various parts facilitates installation. Next, jacketed conductors  30  are fed through sleeves  29  of chamber enclosure  22 , and cable  3  is pushed into chamber enclosure  22  until it butts against end wall  35 . Thin walled portion  26  of chamber enclosure  22  is rolled back upon itself rearwardly to allow easier access to jacketed conductors  30 . Boot seals  31  are slid rearwardly onto jacketed conductors  20  as far as possible. Jacketed conductors  30  are cut to proper length, and the electrical conductor jackets are cut back to expose conductor ends  56 , which are then joined to the electrically conductive elements  57  of connector  1 . The joining of conductors  56  to conductive elements  57  can take place in a variety of well known ways, such as soldering or crimping in the case of electrical conductors, or passage through penetrators in the case of optical fibers. Some clear examples of these ways can be found in U.S. patent application Ser. No. 13/296,406. Boot seals  31  are then slid forwardly into engagement with boot seal nipples  32 . Cable  3  and connector  1  are held horizontally aligned at an axial separation distance that leaves space for a service bend in jacketed conductors  30  and/or the management of optical fibers. Next thin-walled, tubular portion  26  of chamber enclosure  22  is rolled forward. Inward facing shoulder  23  is then seated into seat  24  of connector  1 . Still in a horizontal position, chamber enclosure  22  is now filled with fluid  27 , such as oil, by pinching up the top portion of shoulder  23  from seat  24  and inserting a small tube under shoulder  23  through which a measured amount of fluid  27  is injected into chamber  21 . Excess air is forced out as much as practical. Shoulder  23  is allowed to snap back into sealing position in seat  24 . Termination shell  4  is then slid forward onto the rear of connector  1 , and spring pins  5   a,    5   b  are inserted. Cable grip  12 , washer  11 , and nut  10  are slid forward into the end of shell  4 ; nut  10  is tightened, and the termination is complete. 
       Second Embodiment 
       [0053]    There are alternate ways that would be useful in some circumstances to retain chamber enclosure  22  including boot seal portion  28  in position relative to cable  3  within the termination assembly. As an example of such circumstances, the cable to be terminated might have an outer jacket that&#39;s too soft to be adequately held in place by a push-nut type fastener such as that just described. An alternate termination construction is shown in  FIGS. 9-12 and 14 . In this alternate embodiment plain washer  80  replaces retainer  38  of the earlier embodiment. Washer  80  is sized with an inner diameter slightly larger than the outer diameter of cable  3 , and an outer diameter somewhat larger than inner diameter  15  of shell  4 . Standoff  83  ( FIG. 10 ) has a disc-shaped end  84  with through-hole  85  and standoff rods  86 . Through-hole  85  is sized just slightly larger than the outer diameter of sleeve  33  of chamber enclosure  22 . Standoff rods  86  are inserted into sockets (not shown) in the rear wall of connector  1 . The heavy-walled portion  28   a  of chamber enclosure  22 , including washer  80 , is axially trapped loosely between disc-shaped end  84  of standoff  83  and end wall  52  of termination shell  4 . It cannot move forward because of standoff  83 ; it cannot move backward because of end wall  52 . Sleeve  33  is heavy so as to be robust and not easily stretched forward. Over-pressure within cable  3  is relieved, as before, backward under sleeve  34  via path  70  and further through grip assembly  9  and into the exterior environment. As in the earlier embodiment, ribs  72  on the rearward bell-shaped portion of chamber enclosure  22  guarantee that rear exterior wall  73  of chamber enclosure  22  will not seal to end wall  52  of termination shell  4  when pressed against it. Ventilation is thereby assured between space  36  exterior to tubular wall  26  of chamber enclosure  22  and the external environment. 
         [0054]    Note that in the second embodiment, chamber enclosure  22  is not fastened directly to cable  3 . That is the principal functional difference between the first and second embodiments. Cable  3  is mechanically held in place by cable grip  12 , and chamber enclosure  22  is held in place axially by the entrapment of its heavy walled portion  28   a  including plain washer  80  against end wall  52  of termination shell  4  and disc-shaped end  84  of standoff  83 . Assembly of this alternate embodiment is the same as in the first described embodiment except that one additional part, standoff  83 , has been added to the assembly and retainer  38  has been replaced by plain washer  80 . Apart from the modifications just described the second termination embodiment functions the same as the first one employing retainer  38 . 
         [0055]    In both of the embodiments just described the jacketed conductors  30  within the termination could be either optical fibers or electrical wires. In the case of optical conductors, the jackets could be protective tubes of material such as steel hypodermic tubing which, although rigid, is flexible enough to be embedded in a flexible subsea cable. Looking now at  FIG. 9 , optical fiber protective tube  90  passes out of cable  3 , through the end wall  35  of boot seal portion  28  and thence through constrictive breakout boot seal sleeve  29  into fluid chamber  21 . Within fluid chamber  21 , optical fiber  92  is sealably passed out of tube  90  through a device such as fiber penetrator  91 . Optical fiber protective tubes such as  90  are most often either gel filled or simply empty. The pressure within them is nominally one atmosphere. Fiber penetrator  91  permits optical fiber  92  contained therein to pass undamaged from the one atmosphere pressure interior of protective tube  90  into the possibly high pressure of fluid chamber  21  with no exchange of material between fluid chamber  21  and the interior of protective tube  90 . Examples of fiber penetrators such as  91  can be found in U.S. Pat. Nos. 6,067,395 and 6,608,960. 
         [0056]    Once into fluid chamber  21 , excess amounts of optical fiber  92  can be managed in the well known way of winding flexible elongated elements into a figure-8 pattern as described in U.S. Pat. Nos. 2,634,923 and 2,082,489. The figure-8 pattern keeps long, thin, flexible elements whose ends are fixed from being twisted when coiled. U.S. Pat. Nos. 7,769,265 and 8,731,363 each describe winding tracks which facilitate winding optical fibers into the figure-8 pattern and which also serve as the mounting devices for the wound fiber coils. The &#39;265 optical fiber management invention is for a winding spool and a method of employing the spool, whereas the &#39;363 invention is for a winding apparatus upon which optical fibers are wound and stored. 
         [0057]    A close study of the aforementioned patent-winding techniques, particularly as described in the &#39;265 patent, makes it clear that the winding could equally well be done by hand without the need of any reels or spools. Optical fiber can be hand-wound into a simple coil in the case where the optical fiber has at least one free end, or into a flat figure-8 coil like that just described in the case where both fiber ends are fixed. 
         [0058]    The method of fiber management described in the invention is much simpler. Optical fibers are simply hand wound into a flat coil without the use of any apparatus at all. The resulting fiber coil can then be clipped or otherwise retained in position within chamber enclosure  22 . No reel, track or spool is required.  FIG. 11  is a perspective view of isolated termination elements to clarify the fiber management technique. Diagonally opposed standoff rods  86  protrude forward from disc-shaped end  84  of standoff  83 . Retainer clips  94 , shown in  FIG. 12 , comprise a first through bore  95  sized to tightly fit onto standoff rod  86 , and a second through bore  96  sized to accommodate one or more coils of optical fiber. Slot  98  in retainer clip  94  allows bore  95  to spring slightly outward during installation, thereby firmly gripping standoff rod  86  once installed. Installation of retainer clips  94  can take place by inserting them onto the ends of standoff rods  86  and sliding them into axial position. Slot  97  in clip  94  allows the fiber coil to be inserted into bore  96 . Retainer clips  94  are installed so that slots  97  are oriented generally radially inward towards the longitudinal axis of termination shell  4 . Optical fibers are very springy, and fibers in a circular loop will tend to spring radially outward from the loop&#39;s center. In the invention, that means they will spring radially outward and away from slots  97 , and therefore will not escape from retainer clips  94  through slots  97 . Clips  94  could be made in many different configurations that would work just as well as those shown. 
         [0059]    As discussed in U.S. Pat. No. 8,731,363, in applications where space within the termination is very limited, it is advantageous to manage the optical fibers into a curved figure-8 arrangement. The &#39;363 management apparatus arranges fiber loops on two curved tracks that are either side-by-side axially or opposed radially within the termination chamber. But, there is a much simpler and more compact method of managing the fiber coils into a curved arrangement. Once again, it relies on the spring characteristics of optical fiber. The hand-wound coil shown in  FIG. 11  can be pinched radially into a curved coil as illustrated in  FIG. 14 . Diametrically opposed portions of the coil are inserted into retainer clips  94  and allowed to spring outwards towards their relaxed flat condition, but are constrained by the clips to remain curved. Note that the result is a more compact, single fiber coil, not the two coils required in the &#39;363 patent. 
         [0060]    The invention embodiments herein disclosed are seen to be much simpler than prior art fluid-filled and pressure-balanced cable terminations, and yet they have not sacrificed utility. The simplification enhances reliability by eliminating some of the prior art failure modes. For example, prior art terminations generally have many more sealed interfaces each of which is a potential leak path, and each potential leak path presents the possibility of failure. Assembly errors are diminished in the invented termination by the uncomplicated installation, which in part is due to its having many fewer components than prior art devices. The economical construction of the invention should enable the use of fluid-filled and pressure balanced terminations in a much wider range of electrical, fiber-optical, and hybrid applications than have heretofore been practical. 
         [0061]    The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent presently preferred embodiments of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present invention is accordingly limited by nothing other than the appended claims.

Technology Category: h