Abstract:
An re-enterable enclosure for protecting a cable splice includes a first cover member, a second cover member, and a splice fixation member. The first and second cover members are configured to releasably engage each other and form a cavity for enclosing the cable splice. The cavity is filled with a sealant material for electrically insulating the cable splice and protecting the cable splice from the environment. The cable splice is attached to the fixation member and the cover members are closed around the fixation member and attached splice.

Description:
FIELD OF THE INVENTION 
     The present invention relates to enclosures for cable splices. More specifically, the invention relates to an enclosure for a longitudinally extended cable splice, where the splice includes at least one connector for connecting at least two cables. At least a portion of the enclosure is filled with a sealant to provide electrical insulation and environmental protection to the cable splice. 
     BACKGROUND OF THE INVENTION 
     Longitudinally extended cable splices for low voltage power applications are well known. Such cable splices may be of the butt or inline type, and typically require protection against mechanical impact, electrical shock and the ingress of water or humidity. Typically, between two and four cables are spliced together using a connector, such as a screw connector, a crimp connector or any other suitable connector known in the art. The cross section of the cables are typically in the range of 1.5 to 150 mm 2 , corresponding to diameters in the range of 5 to 30 mm. Accordingly, the dimensions of the enclosures are on the order of several centimeters, at least. 
     The most effective and safest way to achieve a splice enclosure which provides the necessary protection against mechanical impact, electrical shock and ingress of water or humidity is to arrange the cable splice into an splice enclosure or mold into which a hardenable resin is injected. The hardened resin itself then forms the splice body. Unfortunately, this type of splice body does not allow a nondestructive reopening of the splice if required. However, it is often necessary to reopen a splice body for a variety of reasons. 
     Thus, in a large variety of applications it is desirable to have a splice body that allows reentry without destroying the splice body or using undue force. Further, it would be extremely desirable to maintain the possibility of re-closing the protective splice body after the completion of the work on the spliced cables. 
     Several splice enclosures and methods of using such enclosures have been developed which allow reentry into the protective enclosure without destroying the enclosure and/or the splice. Typically, the cable splice is surrounded by material having a viscosity which is low enough that the material can easily penetrate into all interstices of the cable connection. Typically, the material does not harden completely, so that the splice can be relatively easily reopened. However, the viscosity of the material must also be high enough so that it remains in position over a long period of time and does not easily flow out of the splice enclosure. The relatively low viscosity of the material, however, causes another problem. Namely, the cable connection is insufficiently mechanically fixed within the splice body, allowing the spliced cables to move within the splice enclosure in an undesired manner. It thus becomes necessary to provide means for mechanically fixing the cables and the connectors within the splice body, to ensure that uncontrolled movement of the spliced cables does not occur. 
     European Patent No. EP 0328386 describes a splice enclosure which provides the desired electrical and environmental protection to cable splices. The splice enclosure consists of a molded or extruded part where two portions are connected to each other through a hinge. The two portions of the splice body are filled with a sealant material. This configuration is particularly useful for the connection of relatively small cables with a closed system which provides enough pressure onto the cables to keep them in place. 
     PCT Publication WO 97/16869 describes a system in which a molded body consists of two parts which are connected to each other through a hinge, both parts being filled with a gel-type material. Both parts of the body are provided with internal protrusions or alignment buttons which prevent the connector of the spliced cable from freely moving within the splice body. This particular system can work satisfactorily only if the size of the cable connector approximately corresponds to the positioning of the internal protrusions which prevent the cable connector from freely moving within the splice body. Larger connectors cannot be placed into the system at all, and smaller connectors would have an unacceptable freedom of movement. 
     U.S. Pat. No. 5,397,859 describes an enclosure with two parts connected to each other through a hinge, and also provided with a lateral flap. The flap prevents the sealant from moving out of the system in an uncontrolled manner when the enclosure is closed over the splice. The enclosure is designed for use with coaxial cables joined using a special connector. When the spliced cables are pressed between specially designed strain relief means in the enclosure, the splice is provided with the necessary mechanical fixation within the enclosure. The enclosure has limited versatility with respect to the use of different cable types and connectors. 
     U.S. Pat. No. 4,610,738 shows an enclosure for the splice of bundles of telecommunication cables. As in the previous references, two portions of the enclosure are linked together through a hinge. The two cable bundles are fixed together in the middle of the enclosure using a screw which is provided with a slot into which the cable bundles are inserted, and where the bundles are fixed together using an additional nut. The ends of the bundles are then bent in a perpendicular direction and the cables inserted into the gel of the enclosure while the ends of the bundles are sorted. The individual cables of the bundles are connected to each other with a special holding device capable of allowing the fixation of the individual connectors to each individual cable. Such a system would not be useful to protect common low voltage cable splices as described herein, as the connector of the spliced cables would have to be positioned in the location where the holding screw of the reference is positioned. 
     The above-mentioned references describe a variety of enclosures for cable splices. However the references are only useful with specific configurations of either the cables or the entire cable splice. For relatively small cable and connector dimensions, the sealant compressed within the enclosure provides the necessary mechanical stabilization. In other configurations, alignment protrusions are arranged within the enclosure to provide mechanical stability. However, the alignment protrusions limit the use of the enclosure to splices having a narrowly defined geometry. The strain relief means which are provided in the enclosure are restricted to cables which fall within a small range of sizes. Finally, the use of fixation screws in the middle of the enclosure preclude the use of the enclosure with typical low voltage splice connectors. 
     It would therefore be desirable to provide a re-enterable splice enclosure which is usable with cables of widely varying diameters and which provides the necessary electrical and environmental protection, as well as a means for fixing the cables securely within the enclosure. 
     SUMMARY OF THE INVENTION 
     The present invention provides an easily re-enterable splice enclosure which securely holds a wide variety of connectors and splice configurations. The inventive enclosure comprises a first cover member and a second cover member, each having two longitudinal sides and two end walls. The cover members are configured to releasably engage each other and form a cavity for enclosing a cable splice. The cavity is filled with a sealant material for electrically insulating the cable splice and protecting the cable splice from the environment. The cables of the cable splice project from at least one of the end walls of the cover members. A cable fixation member is provided for attachment to the cable splice. The fixation member and an attached cable splice are inserted into the cavity formed by the first and second cover members. The fixation member is configured such that a wide variety of cable splices may be attached to the fixation member. 
     The advantage of having a separate fixation member is that the cable splice can be fixed to the fixation member without interfering in any way with the cover members filled with the sealant (i.e., the cable splice is securely fixed to the fixation member prior to being inserted into the sealant filled cavity). Furthermore, a separate fixation member allows a large variety of cable splices to be used with the enclosure. The only restriction is that the splice must fit within the enclosure cavity formed by the cover members. 
     For effectively securing the cable splice within the completed enclosure, it is advantageous to have the attachment points on the fixation member positioned such that when the fixation member and attached splice are inserted into the cavity the attachment points are adjacent the end walls of the cavity. This ensures that the cable splice is longitudinally aligned with the enclosure when the fixation member and attached splice are inserted into the cavity. 
     For a particularly versatile fixation member, it is advantageous to provide the fixation member with multiple attachment points and multiple manners of attaching a splice to the fixation member. For example, the fixation member may be provided with bars which extend laterally across the cavity and which may provide multiple attachment points. Attachment of the splice to the fixation member can be accomplished with strings, wires, threaded fasteners, and more preferably commonly used cable ties. Another preferred attachment method would be the use of clamps which can secure the cable to the fixation member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention described herein will be best understood from the accompanying drawings which illustrate the preferred embodiments of the invention. The invention, however, is not intended to be limited to the embodiments illustrated, and should be construed as defined by the claims presented below. 
     FIGS.  1   a  and  1   b  are perspective views of the top and bottom sides of a first embodiment of the inventive enclosure. 
     FIG. 2 is a perspective view of a second embodiment of the enclosure. 
     FIG. 3 is a perspective view of the invention as shown in FIG.  1   b , showing the cavities of the first and second cover member filled with a sealant. 
     FIG. 4 corresponds to FIG. 3, with optionally used components removed from the fixation member of enclosure. 
     FIGS.  5   a ,  5   b  and  5   c  are cross-sectional views of the embodiment of FIGS.  1   a  and  1   b , showing the method for preparing the enclosure for shipment and assembly. 
     FIG. 6 is a perspective view of the enclosure of FIG.  5   c.    
     FIG. 7 is a perspective view showing the fixation of a first configuration of a cable splice onto the fixation member of the enclosure. 
     FIG.  8   a  is a perspective view showing the fixation of a second configuration of a cable splice onto the fixation member of the enclosure. 
     FIG.  8   b  shows the enclosure and splice of FIG.  8   a  with the cables removed. 
     FIG.  9   a  and  9   b  are cross-sectional views of the fixation member illustrating two different methods for fixing a cable to the fixation member of the enclosure. 
     FIGS.  10   a - 10   g  are cross-sectional views of the embodiment of the enclosure shown in FIGS.  1   a  and  1   b , showing the progression of steps for inserting the cable splice into the enclosure. 
     FIG. 11 is a perspective view of the completed assembly of a cable splice protected by the inventive enclosure described herein. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS.  1   a  and  1   b  illustrate a first embodiment of the inventive enclosure for longitudinally extended cable splices. The enclosure  10  is preferably formed through a molding process and comprises a first cover member  12 , a second cover member  14 , and a cable fixation member  16 . The first cover member  12  and second cover member  14  include cavities  18 ,  20 , respectively, which are designed to hold a sealant material  50 ,  52 , respectively (shown in FIG.  3 ). Fixation member  16  includes a flat plate  22 . The plate  22  is designed to be broken off from fixation member  16  prior to use of the enclosure and can be either discarded or used as a separation means for the spliced cables in a manner described below. 
     First cover member  12  and second cover member  14  have longitudinal side walls  17 . A hinge  24  extends between the side walls  17  of first and second cover members  12 ,  14 , thereby linking cover members  12 ,  14 . The fixation member  16  is hinged to the side wall  17  of second cover member  14  opposite first cover member  12  through hinges  26 ,  28 ,  30  and  32 . Of course, the number and precise location of the hinges may be altered without affecting the scope of the invention. Hinges  24 ,  26 ,  28 ,  30  and  32  are preferably integrally molded with cover members  12 ,  14  and fixation member  16 , and have an area of reduced thickness  33  which defines the bending axis of the hinge. This type of hinge is often referred to as a “living” hinge. Of course, other well known types of hinges could also be used, including films or tapes. In addition, if the hinges are not integrally molded with the cover members  12 ,  14  and fixation member  16 , separate hinge members could be inset molded into the cover members  12 ,  14  and fixation member  16 , or could be attached after the molding process, such as by an adhesive. 
     The first cover member  12  is provided with latching tabs  34 ,  36  which are positioned to engage the openings  38 ,  40  of second cover member  14  when the first cover member  12  and second cover member  14  are folded together. First cover member  12  also includes a latching tab  41  for engaging the outer edge of second cover member  14 . As noted above with respect to hinges  24 ,  26 ,  28 , and  30 , the number and position of the latching tabs may be altered without affecting the scope of the invention. 
     Cavities  18  and  20  within cover members  12  and  14  extend between intermediate walls  42  which are arranged at a distance from the end walls  44  of the cover members  12  and  14 . In this manner, an additional reservoir  46  is created at either end of cover members  12 ,  14  between intermediate walls  42  and end walls  44  of the cover members  12  and  14 . The intermediate walls  42  and end walls  44  are provided with frangible grooves  45 . Grooves  45  create a variation in the thickness of walls  42 ,  44  such that thin and thick wall portions are created. The thickness variation is such that the thin portions allow the walls to fracture when, for example, pressing a cable against them. The thickness variation will depend upon the total thickness of the material, but may, for example, be between 0.15 mm and 1.5 mm in a typical application. It can also be seen in the Figures that the bottom surface of cavities  18  and  20  are provided with ridges  48 . Ridges  48  improve the adhesion between the enclosure and the sealant  50 ,  52  provided in the cavities  18  and  20 . 
     It should be noted that although the embodiments of the invention described herein illustrate both cover members  12 ,  14  having cavities  18 ,  20 , respectively, it is equally possible that only one of cover members  12 ,  14  have a cavity, while the other mating cover member functions substantially as a lid. In such an embodiment, sealant material would only be provided in the one cover member having a cavity. Although such an embodiment is not illustrated, it is contemplated to be within the scope of the invention described herein. 
     A second embodiment of the enclosure  10  is shown in FIG.  2 . The embodiment of FIG. 2 is substantially similar to the embodiment of FIGS.  1   a  and  1   b  described above, and like components are similarly numbered. The primary difference between the second embodiment of FIG.  2  and the embodiments of FIGS.  1   a  and  1   b  is that the embodiment of FIG. 2 does not include hinges to link cover members  12  and  14  and fixation member  16 . Instead, cover members  12 ,  14  are provided with latches  34 ,  36  on both sides of the cover members. As can be seen from FIG. 2, the cover members  12 ,  14  are identical so that they may be produced from the same mold. In all other respects, the assembly in the use of the enclosure  10  shown in FIG. 2 is like that described for the embodiment of FIGS.  1   a  and  1   b.    
     FIG. 3 is essentially identical to FIG.  1   b  and shows the enclosure  10  having sealant  50  in cavity  18  and sealant  52  in cavity  20 . Sealants  50 ,  52  will typically have a viscosity which is low enough to allow the sealant to flow into any voids surrounding the spliced cables and the associated connectors, but yet high enough to prevent the sealant from flowing out of the enclosure  10 . 
     The configuration of the enclosure  10  as shown in FIG. 3 is nearly ready for use. To use the enclosure of FIG. 3, it is first necessary to remove the flat plate  22  from the fixation member  16 , resulting in an enclosure as shown in FIG.  4 . After removing the flat plate  22 , the fixation member  16  consists of two longitudinal side bars  54 ,  56  which are connected by lateral bars  58  and  60 . The longitudinal bar  54  is connected to hinges  26 ,  28 ,  30  and  32 . The longitudinal bars  54 ,  56  are designed in a manner such that when folding the fixation member  16  into the second cover member  14 , the bars  54 ,  56  penetrate into the sealant  52  and form a barrier which prevents the sealant  52  from leaking out the longitudinal sides of the enclosure  10 . The lateral bars  58 ,  60  are each provided with several openings or slots  62 . In the example shown, each bar  58 ,  60  contains  4  rectangular openings  62 . In addition, the lateral bars  58 ,  60  are provided with teeth  66  to allow better gripping of the spliced cables (not shown). 
     FIGS.  5   a ,  5   b  and  5   c  illustrate a manner in which the enclosure  10  can be prepared for shipment and assembly. FIG.  5   a  corresponds to the cross-sectional view of the enclosure  10  as viewed along line  5 — 5  in FIG.  4 . FIG. 5b illustrates first cover member  12  bent about hinge  24 , with an optional release liner  70  placed over the sealant  52  in the second cover member  14 . The release liner  70  preferably consists of a siliconized paper or polyethylene foil, Teflon foil, plastic sheet of polyester, or a similarly suited material which will not readily adhere to the sealants  50 ,  52 . The first cover member  12  is further rotated on hinge  24  until tabs  34 ,  36  engage and latch into holes  38 ,  40 . This configuration of the enclosure is particularly suitable for shipment of the enclosure  10  prior to assembly of the splice. In this manner, the sealant materials  50 ,  52  are well protected in the enclosure  10 , while the connection of the cable splice onto the fixation member  16  can be completed independently from and without damage to the sealant material  50 ,  52 . A perspective view of the configuration of FIG.  5   c  is shown in FIG.  6 . 
     To use the enclosure  10 , the splice cables are attached to fixation member  16 , as shown in FIG.  7 . Although FIG. 7 shows cover members  12 ,  14  in a separated or unlatched configuration, the cover members  12 ,  14  can also be left in a latched or closed position during the process of assembling the cable splice to fixation member  16 . In the example shown in FIG. 7, a cable splice consists of a single cable  72  on one side and two cables  74 ,  76  on the opposite side which are connected to each other through a crimp connector  78 . Of course, the connector can be of any type well known in the art, such as a screw connector. The cables  72 ,  74 ,  76  are fixed onto the bars  58 ,  60  which, as described above, are provided with openings  62 , as well as teeth  66 . The cables  72 ,  74 ,  76  are connected to bars  58 ,  60  using cable ties  80  which pass through two of the openings  62  in each of the bars  58 ,  60 . 
     FIGS.  8   a  and  8   b  correspond to FIG.  7 . FIG.  8   a  shows a slightly different configuration of cable splice fixed onto the fixation member  16 . In FIG.  8   a , the cables  86 ,  88  and  90  each comprise three individual wires. For each of the wires a connection is established using a connector  92 . Each of the wires of the cables  86 ,  88  and  90  are similarly connected. The previously removed flat plates  22  are inserted between the spliced cable wires to form a solid insulative barrier between the wires. In the example of FIG.  8   a , the provision of a solid insulating barrier between the individual spliced wires is important when connectors  92  are not insulated connectors, as the sealant  50 , 52  alone may not provide a sufficient insulating distance between the wires. FIG.  8   b  more clearly shows how the previously removed flat plates  22  are interlocked to form the separation means for the individual wire connections of the cables  86 ,  88  and  90 . In this manner, inadvertent short circuits may be prevented between the spliced wires of the cables  86 ,  88  and  90 . The advantage of this approach is that no additional components are necessary, as the flat plate  22  simultaneously serves as a runner during the molding process and as a separation means when necessary. 
     In addition to the examples shown in FIGS.  7  and  8   a , other configurations of cable connections can be thought of, with the restriction of the number of cables essentially limited only by the size of the enclosure  10 . Further, it is possible to house, for example, two completely separate splices in one enclosure provided that the connections would fit into the enclosure due to their geometry. 
     FIGS.  9   a  and  9   b  illustrate more closely the manner in which the cables are attached to the fixation member  16  and specifically to the bars  58 ,  60  of fixation member  16 . In FIG. 9A, it can be seen that bar  58  is provided with four rectangular openings  62   a ,  62   b ,  62   c  and  62   d . The cable tie  80  passes through two of the openings  62   a  and  62   b  and affixes cable  72  using a well-known latching means  100 . It will be readily recognized that any suitable cable tie could be used. Preferably, the cable ties are selected of a suitable material to ensure proper fit in openings  62   a - 62   d.    
     FIG.  9   b  shows an alternate manner of securing cable  72  to bar  58 . In FIG.  9   b , cable  72  is fixed onto bar  58  using a clamp  102  which is provided with multiple teeth  104 ,  106 . The teeth  104 ,  106  of clamp  102  are pushed into the openings  62   a  and  62   b  as far as necessary until teeth  104 ,  106  engage the walls of holes  62   a  and  62   b  and provide the necessary holding force. In addition to the cable ties  80  and clamp  102  shown in the Figures, it will be recognized that other methods may be used to secure the cables to fixation member  16 . For example, the cables may be secured by the use of wires, strings, threaded fasteners (such as screws), or any other suitable method. 
     FIGS.  10   a  through  10   g  show the completion of the assembly procedure after having fixed the cables onto the fixation member  16 . FIG. 10 shows a splice configuration corresponding to those of FIGS. 7 and 8 with the cover members  12  and  14  in a closed position. As described above, the advantage of this configuration is that during the fixation of the cables to the fixation member  16 , the sealants  50 ,  52  are well protected. After fixing the cables onto fixation member  16 , the enclosure is opened by releasing the tabs  34 ,  36  and rotating first cover member  12  away from second cover member  14  about hinge  24  (FIG.  10   b ). At this time, any release liner  70  which has been inserted to keep sealants  50 ,  52  from adhering to each other may be removed. FIG.  10   c  shows the subsequent step where the cover members  12 ,  14  are completely opened. FIGS.  10   d  and  10   e  show the rotation of the fixation member  16  about hinges  26 ,  28 ,  30  and  32 . Fixation member  16  is rotated until the cables  74 ,  76  penetrate into sealant  52 . At this point, the sealant  52  is displaced by cables  74 ,  76  and may also penetrate onto the longitudinal sides  17  of the enclosure  10 . In this case, the longitudinal bars  54 ,  56  of fixation member  16  ensure that the sealant can not move over the longitudinal sides  17 , but rather are pushed in a direction around cables  74 ,  76 . 
     After cables  74 ,  76  are embedded in sealant  52 , cover member  12  is closed about fixation member  16  and cables  72 ,  74  until latches  34 ,  36  engage openings  38  and  40  of cover number  14 . Cables  74  and  76  are then completely sealed by sealants  50 ,  52 . 
     FIG. 11 shows a perspective view of the configuration after the assembly is completed. It shows the end walls  44  of cover members  12 ,  14  fractured along grooves  45  to allow the cables  74 ,  76  to exit the enclosure  10 . A similar fracturing of intermediate walls  42  also occurs within the enclosure. Any sealant which escapes past intermediate walls  42  is trapped in reservoir  46  and is prevented from exiting the enclosure  10 .