MXPA99004147A - Wrap type cable closure end seal - Google Patents

Abstract

An end seal (15) for splice closures or for terminals comprising a core portion (20) of a flexible resilient material. The core portion (20) has an outer periphery and openings (24) extending through the core (20). The openings (24) communicate with the outer periphery. A tail portion (22) is integral with and extends from the core periphery to be wrapped about the core (20) and the cables to be placed in the openings (24). A sealant strip extends around the cables and between the abutting peripheral surface of the core (20) and the wrapped tail portion (22). The strip is responsive to electrical or electromagnetic stimulation for heating the sealant strip and causing the strip to bond with adjacent contact surfaces of the cable and the body.

Description

ENVELOPE CABLE CLOSURE END SEAL BACKGROUND OF THE INVENTION This invention is concerned generally with a cable closure end seal and more particularly with a surround end seal for use in sealing the end area of a closure or terminal by means of which the cables are positioned and seal the area around the cables to prevent moisture or other contamination from entering the closure. There are several methods for joining or splicing together the ends of telecommunication cables. When doing this, there are many important considerations such as the use of compatible materials, how many cables are spliced, whether the spliced cable will be buried in the ground, submerged in water or suspended in the air, what heat source is required to make the joint , for example, flammable gases, if the joint will need to be reopened and re-done without interruption of the work circuits, if the joint will have sufficient mechanical strength and if the cost is feasible. The communication cables are usually constructed from a bundle of conductors surrounded by a metal housing of resistance and interference and an external protective coating, usually made of polyethylene. When such cables are spliced _ and reassembled - the strength and integrity of the reassembled cable are critical. One REF .: 30057 Envelope or a closure body is used to sealingly surround the splice. A "persistent problem in the use of splice closures involves the need for a complete seal around the splice or closure body.Many prior art splice closures perform the seal by providing a complex internal arrangement of nuts, clamps, thermal shrinkage joints and tubes, also as encapsulation gels and resins in various combinations In addition to the fact that these closure methods require a significant type of assembly, closures will still frequently leak or rupture, particularly along their seals This problem is even more acute in sealing the closure to the cable liner, where even the slightest defect can result in migration and moisture along the liner or the inner surface of the closure.A lack of a complete seal _ (hermetic) can also be particularly detrimental to pressurized closures, although these seals can be reinforced by When using adhesives, the adhesive bonds formed are normally weak due to the low surface energy of the closure material and cables, usually polyethylene. An alternative technique for sealing thermoplastic polymers such as polyethylene is that of fusion (or bonding). This technique generally involves heating the material until it melts on its sealing surface, to cause it to flow at the interfaces and can be used for splice solders, coupling joints and repair sleeves. Two specific methods of fusion bonding: (i) direct heating and (ii) induction heating, can also be used to activate thermosetting and thermoplastic adhesives (thermal fusion), as well as thermoelastic (thermal shrinkage) tubes. Induction heating is sometimes referred to as bonding. { electromagnetic (EMB). In direct heating (also known as resistance heating), the heat is applied to the thermoplastic article to be bonded by directly joining the heating elements to the article. The current flows through the elements to heat them. The current is fed by a power supply connected directly to the elements, but the heating is not always efficient. An advantage of such a system is that it does not involve radiation emission, but there are disadvantages, such as non-uniform heating of the material. Induction heating has been widely used to seal and bond polymeric materials. A composite binding material (CMB) is formed by supplying magnetically reactive susceptors in a thermoplastic carrier that is compatible (miscible) with the bodies thermoplastics to be soldiers. When this material is placed in an alternating electromagnetic field, the H field induces the heating in the magnetic material. The heating can be caused by one of two effects: loss of hysteresis or resistive loss of eddy currents induced. Field E does not interact with magnetic particles. The techniques of direct heating and induction can be combined. The end seals can be used with thermal fusions as an alternative bonding material. The thermal melt is placed between the resistance wires and the wires are heated to form a junction between the cables and the end sealing surfaces. The fusion by thermal fusion can be used with different end sealing materials such as foams, elastomers and thermoplastics, but the bond strength is weaker than the fusion bond seal. Prior art concerning end seals for splice closures or terminations is replete with systems to fit a variety of closure ends. One of these seals comprises a core portion of a flexible, resilient self-adhesive material. The portion of the core or central portion has an outer periphery and openings extending therethrough. The openings communicate with the outer periphery. A later portion or elongate flexible tail portion, is integral with and extends from the periphery of the core to be wrapped around the core portion and the wires placed in the openings. However, this material may not be appropriate for some applications. Unfortunately, an appropriate solution to the problems associated with ease of installation, seal integrity and strength has not been satisfactorily met by the prior art. Therefore, what is needed is an end seal for use of sealing the area at the end of a closure or terminal, whereby the cables are positioned and seal the area around the cables to prevent moisture or other contamination enter at closing. It is also highly desirable to provide a device that is easy to install that is capable of maintaining the integrity of the seal and strength and can accommodate various numbers of cables and wire sizes.

BRIEF DESCRIPTION OF THE INVENTION Thus, the present invention provides an apparatus for sealing the ends of the cable closure body used for sealingly covering and protecting the cable splices to prevent moisture or other contamination from entering the closure. For this purpose, a cable end seal comprises a body that includes a portion of core or central portion connected to a rear portion or extended tail portion. The core portion has an outer peripheral surface and spaced ends. The peripheral surface includes a plurality of cylindrical openings through which the core portion extends between the ends. One edge of each opening communicates with the outer peripheral surface of the core portion to define an entry slot for each opening. The back portion or tail portion is flexible and has opposite ends. A first end is integral with and extends tangentially from the outer peripheral portion of the core. The tail is of sufficient length to wrap around the peripheral surface of the spliced core with it to cover the inlet slot of each opening and a cable to be placed therein. A second free end of the tail is tapered to a reduced thickness. Elements (or means) are provided to extend adjacent the glue and core portions and along an annular surface of each cylindrical opening, the elements are sensitive to electrical stimulation for heating the adjacent material for bonding each cable and the body to a sealed unit. A main advantage of the present invention is that a one-piece end seal can capture a plurality of wires that extend through openings in the openings. the end stamp. An electrical stimulus can be used to heat and splice the surfaces of the cable sealing element together in a sealed unit. This could be. improved by using a continuous sealing strip having conductors embedded therein to heat and seal the cables in the holes and to seal the coupled surfaces of the body portions when they are joined together.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view illustrating an embodiment of the end seal according to the present invention. Figure 2 is an end view illustrating another embodiment according to the present invention with the tail portion partially in section by illustration. Figure 3 is an end view illustrating a further embodiment according to the present invention with the tail portion partially in section by illustration. Figure 4 is an end view illustrating a further embodiment according to the present invention with the tail portion partially cut-off by illustration. Figure 5 is an end view illustrating the seal of the end of Figure 4 with the tail portion wrapped around the core portion and a cable that extends through each cable hole. Figure 6 is a bottom view illustrating an embodiment of the end seal according to the present invention. Fig. 7 is a cross-sectional view taken along line 7-7 of Fig. 1, illustrating one embodiment of the glue profile according to the present invention. Fig. 8 is a partial view illustrating an embodiment of the tail section according to the present invention. Fig. 9 is a cross-sectional view illustrating another embodiment of the glue profile according to the present invention. Figure 10 is an end view illustrating yet another embodiment of the end seal according to the present invention. Figure 11 is an end view illustrating the seal of the end of Figure 10 with the glue portion wrapped around the core portion and cables extending through two holes for the cable. Figure 12 is a perspective view illustrating the end seal of Figure 5 assembled with a splice closure box.

Figure 13 is a perspective view illustrating one embodiment of a sealing strip according to the present invention. Figure 14 is a perspective view illustrating another embodiment of a sealing strip according to the present invention. Fig. 15 is a partial perspective view illustrating an embodiment of a grooved tail according to the present invention. Figure 16 is a partial perspective view illustrating one embodiment of a sealing strip according to the present invention. Figures 17-21 are partial plan views illustrating embodiments of wire configurations according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to Figure 1, an end seal designated generally as 15, formed of an elastomeric polyolefin material and comprising a body 18 including the portion of the core 20 and a portion is illustrated in isometric view. 50. The core portion 200 is formed of a circular configuration and has a plurality of openings 24 defined by arcuate walls 25 extending between a pair of opposite ends 26, only one such ends 26 is shown in Figure 1. The walls 25 begin at the end on an outer peripheral surface 30 of the portion of the core 20 to form slot-like openings communicating with the openings 24 to allow the core portion. 20 receive cables or endless wires. An inner surface 32 of the tail portion 22 extends from one of the openings 24 generally tangential to the wall 25 and from a position in the slotted opening. The tail portion 22 has a thickness and cross section in general uniform along its length until near a free end 36 where its thickness begins to decrease or taper to a free edge to form a smooth transition to an external surface 34 of itself after it is wrapped around the peripheral surface 30 of the portion of the core 20 and the exposed portion, if any, of a wire or wire disposed in each of the openings 24. Figure 2 illustrates an end seal 15 according to the present invention, wherein the portion of the core 20 is formed with a pair of openings 24. Figure 3 illustrates an end seal 15 wherein the portion of the core 20 has openings 24 of different diameters positioned around the outer peripheral surface.30. Figure 4 illustrates a core portion 20 with a plurality of openings 24 which are not symmetrical. The tail portion 22 can also have a variety of configurations. Without However, it is important that the tail portion 22 be of sufficient length to wrap around the outer peripheral surface 30 of the core portion 20 at least once, approximately 360 ° around the center. The tail portion 22 may have any given length greater than the circumference of the outer periphery of the core portion 20, however. Figure 5 illustrates the tail portion 22 wrapped around a core portion 20 with the tail portion 22 that "makes more than one wrap around the core portion 20 and three wires 28 disposed at the end of the seal. Figure 6 illustrates that the tail portion 22 can also be tapered in the longitudinal direction to change the width of the tail portion such that it becomes narrower near the free end 36. Figure 7 illustrates that the portion of tail 22, either of a uniform width or of a decreasing width, can also be tapered in the transverse direction to cause the inner end of the seal to have an outer diameter different from that at the outer end, to result in a cone shaped or tapered end seal In this embodiment, the opposite edges of the tail portion 22 have different thicknesses along the length of the tail portion. is can decrease towards the free end The tail portion is adapted to make a plurality of turns around the core portion.

Figure 8 illustrates a tail portion 22 that is provided with pre-formed grooves or slots 31 that allow the tail portion 22 to be easily braided to a different length by separating the end portion beyond a slit 31. As is illustrated in the cross-sectional view in Figure 9, the tail portion 22 can also be formed with engaging ridges or ribs 33 and slits 35, formed on opposite surfaces of the tail portion 22. In this embodiment, the shoulder 33 is trapezoidal in shape and extends along the outer surface 34 of the tail portion when wrapped and on subsequent turns, the slit 35 covers the shoulder 33 to increase the path along the seal between the wraps and the coefficient of friction, such that the axial force along the axis of the end seal is greater and the envelopes of the tail portion 22 can not slide one relative to the other. Figure 10 illustrates an end seal 15 with a portion of the core 20 that is rectangular or oblong as opposed to being generally circular. The portion of the core 20 is of a shape having generally convex surfaces such that the tail portion 22 can be wrapped tightly around the outer surface to form a seal to moisture for closure. The core portion 20 is formed with a plurality of cable receiving openings 24. In Figure 11, the end seal ~ 15 is shown with a pair of cables 28., with one or more conductors placed in two of the openings 24 and a plug 40 is illustrated in the third opening to show that the end seals of the present invention are versatile and if a cable is not required the seal will still work. The cap 40 being a solid cylindrical element, can be placed in the additional opening 24 with the glue portion wrapped around it. The opening 24 can be formed with slots on its inner surface, which extends around its axis and the plug 40 can be formed with ribs surrounding the outer cylindrical surface which engage with the slits, such that the plug , is not easily expelled from the opening 24. The selection of material for the end seal of the present invention requires good bonding capabilities to provide an appropriate seal, also as to provide resistance to contamination, moisture and pressure. The union of joints to be sealed involves the union of the selected material to itself, cable linings and sealing elements that can be used. Since the sealing is carried out by heating, the selected material must also be appropriately sensitive to the union by fusion. As such, the polyolefin elastomers are suitable and from that group, the flexible dielectric alpha olefin copolymer sold under the name ENGAGE by the Dow Chemical Company of Midland, Michigan, is preferred. The selection of material for the sealant of the present invention requires an affinity to produce a satisfactory fusion bond. Thus, where a sealant "is used in the present invention there are several alternatives." First, however, it should be understood that an appropriate joint can in some instances be carried out by resistance heating of the spliced surfaces by placing of the nichrome wire on or near the splicing surfaces Electrical stimulation of the wire will heat the surrounding material sufficiently to bond all heated splicing surfaces and applied compression by means of the curing process, proper welding can be produced. Nichrome can be in the form of typical round wire or a flat strip and can be coated, embedded or laminated into a strip of appropriate sealant material, such as polyethylene.The electrical stimulation of the wire will heat the surrounding sealant material and the spliced surfaces. be sealed, all splicing surfaces can be sealed from sta way Improved by the additional or excess sealant material, which will help to provide appropriate seals with applied pressure through the melting process. In addition to using a wire coated by, embedded in, or laminated to a strip of sealing material such as polyethylene, a susceptor-containing material can be added to the sealant, which absorbs RF (radio frequency) energy and transfers it to thermal energy. In this case, the wire is preferably copper and functions as an antenna. The heat produced causes the susceptor containing material that includes a polyethylene binder and the splicing surfaces to be sealed. Here, once again, the seal is enhanced by the additional material by the excess that will help to provide proper seals with applied pressure through the melting process. While it is not necessary to discuss every possible iteration of combination sealant material, susceptor material and wire types, it is clear that the seal is improved in view of the foregoing. In accordance with the present invention, a seal is provided by fusion along the splice 50, FIG. 5 between the peripheral surface 30 of the core and the inner surface 32 of the glue 22. The seal bonded by fusion is also provided along the annular wall 25, for example figure 2, of each opening Cylindrical 24. The seal is made by providing a resistance wire illustrated by dashed line 52, Figures 2 and 10, applied to, or embedded in, the appropriate surfaces as discussed above. The resistance wire 52 forms a closed circuit in which alternating current (AC) or direct current (DC) is applied for energization. In addition, the resistance wire 52 can also be applied to the outer surface 34, FIG. 1, of the tail 22. In this way, when the tail 22 is wrapped around the core 20, the outer peripheral glue surface 34 can be attached to a splice closure box 54, FIG. 12, in which the end seal 15 is provided to be placed. Also, the cables 28 can be joined in the openings 24. The resistance wire 52 can be a rounded cross section or may be in the form of a braided wire or flat ribbon, Figures 13 and 14. The wire 52 may be molded into a sealing strip 56 of polyethylene material or placed between strips of laminated polyethylene sheets to form a laminated sealing strip 58. Thus, the strips 56 or 58 can be placed along the appropriate surfaces as mentioned above. A slit 60, FIG. 15, can be provided on the inner surface 32 of the tail 22 that includes a prominent tongue 62. Each of the straps 56 and 58 can be positioned in the slit 60. and retained in the same by providing an opening 64, figure 16 and the strip for a retaining coupling with the tongue 62. Various configurations and geometric shapes, figures 17-21, of the resistance wire 52 can be applied to the core 15. It has been noted that it is advantageous to consider such configurations to increase the density of the resistance wire in the cylindrical openings 24 to ensure proper heating around the outer annular surfaces 66 of the cables 28, figures 11 and 12 and the proper sealing of the cables 28 in the openings 24. In service, the cables are - placed in the appropriate openings of the end seal and the tail portion is wrapped around the core portion. The resistance wires extend along the splice surface between the glue and the core and extend between the annular walls of the openings and the cable surfaces therein provide sufficient heat, when energy is applied, to cause the surrounding sealing material to stick or stick to all contact surfaces. Similarly, when the end seal is to be placed in a splice closure body, the wires around the outer periphery of the wrapped tail can provide the joint required to seal the end seal within the closure body. To improve the sealing, additional sealant material, in the form of a sealing strip that has the wires buried in it. In this way, the aggregate sealer improves the fusion bonding and seal integrity process. As can be seen, the main advantage of the present invention is that it provides a one-piece device, when it is attached around cables that extend through the holes, which form seals between the peripheral surfaces of the cable and the holes that also they form seals between the movable body portions and the end seal when those portions are joined together. The seal of the joined end by fusion has advantages over the previous procedures for the integrity of the end seal. In accordance with the present invention, the end seal is flexible to accommodate a multiple range of cable diameters. The bonding strength by fusion between the cables and the seal is greater than with a conventional thermal fusion system. The end seal is a one piece design that does not require cutouts for multiple cable diameters. The end seal material can be reinserted and removed from the cables when cutting the material. The end seal of the present invention does not require. the use of a torch for heating.

The utility of the invention allows the end seal to be a main sealing element for cable closure bodies, since it is sealed to the cable surfaces and is also sealed to the attached cable seal body. This forms a hermetic seal to the air, to the pressure and humidity to the eternal elements. The basic features of the end seal provide integrity in tension relief, acceptance of different cable diameters and total seal integrity between the relatively movable end seal body portions, the cables extending therethrough and the closing body in which it is mounted. In addition, the use of a continuous sealing strip to seal the cables in the orifices and to seal the coupled surfaces of the body portions when coupled together, provides a facilitated installation. Although illustrative embodiments of the invention have been shown and described, a wide range of modifications, changes and substitutions are contemplated in the foregoing description and in some instances some features of the present invention may be employed without corresponding use of other features. Thus, it is appropriate that the appended claims be interpreted broadly and in a manner consistent with the scope of the invention.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers.

Claims (21)

1. Claims Having described the invention as above, the content of the following claims is claimed as property. A cable end seal, characterized in that it comprises: a body portion including a core portion or central portion attached to a rear portion or tail portion, extended; the core portion has an outer peripheral surface and spaced ends, the peripheral surface includes a plurality of cylindrical openings through which the core portion extends between the ends, an edge of each opening communicates with the outer peripheral surface of the core. the core portion to define an entry slot for each opening; the tail portion is flexible and has opposite ends, a first of the opposite ends of the tail is integral with and extends tangentially from the outer peripheral surface of the core portion and has a length sufficient to wrap around the peripheral surface of the core portion. the core portion spliced therewith to cover the entrance slot of each opening and a cable to be placed therein, a second free end of the tail being tapered to a reduced thickness; Y means or elements extending adjacent between the splice and the glue and core portions and along an annular surface of each cylindrical opening, the means or elements are sensitive to an electrical stimulation to heat the adjacent material, for bonding or gluing the body and each wire to be "placed therein in a sealed unit 2. The end seal according to claim 1, characterized in that each cylindrical opening has a different diameter from the other cylindrical opening. of the end according to claim 1, characterized in that the tail portion is provided with oblique slits in spaced relation along the length thereof to selectively split the tail into a slit to shorten the length of the tail. 4. The end seal according to claim 1, characterized in that the portion of the core is generally circular. 5. The end seal according to claim 1, characterized in that the portion of the core is generally oblong. 6. The end seal according to claim 1, characterized in that the tail portion is formed with a shoulder or rib on a surface and a slit on an opposite surface. 7. A cable end seal, characterized in that it comprises: a body including a portion of the core or central portion attached to a rear portion or tail portion, extended; the core portion has an outer peripheral surface and spaced ends, "the peripheral surface includes a plurality of cylindrical openings through the core portion extending between the ends, an edge of each opening communicating with the outer peripheral surface of the core portion to define an entrance slot to each opening, the rear portion or tail portion is flexible and has opposite ends, a first of the opposite ends of the tail is integral with and extends tangentially from the outer peripheral surface of the portion of core and has a sufficient length to wrap around the peripheral surface of the core portion in connection therewith to cover the inlet slot of each opening and a cable to be placed therein, a second free end of the tail is tapered to a reduced thickness; a sealing strip extending along the junction between the glue and the core portions and an annular surface of each cylindrical opening; and elements in the strip sensitive to electrical stimulation to heat the sealing strip to join the body and each cable to be placed therein in a sealed unit. 8. The end seal according to claim 7, characterized in that each cylindrical opening has a different diameter from another cylindrical opening. 9. The end seal "according to claim 7, characterized in that the tail portion is provided with oblique slits in spaced relation along the length thereof, to selectively split the tail into a slit to shorten the length The end seal according to claim 7, characterized in that the core portion is generally circular 11. The end seal according to claim 7, characterized in that the core portion is in general oblong or rectangular 12. The end seal according to claim 7, characterized in that the tail portion is formed with a rib on a surface and a slit on an opposite surface. 13. The end seal according to claim 7, characterized in that the tail portion is formed with a slit on a surface thereof. 14. The end seal according to claim 13, characterized in that the sealing strip is positioned in the slit. 15. The end seal according to claim 14, characterized in that the slit includes a protruding tongue and the sealing strip has an opening "therein for receiving the tongue to retain the strip in the slit. according to claim 7, characterized in that the means responsive to electrical stimulation consist of a conductive wire 17. The end seal according to claim 7, characterized in that the means sensitive to electrical stimulation consist of a conductive strip. 18. The end seal according to claim 1, characterized in that it further comprises that the tail is wrapped around the core and an outer peripheral surface of the tail around the core includes additional means extending around it, sensitive to electrical stimulation to heat the external peripheral tail surface, in such a way that the external peripheral tail surface can be attached to a splice closure box to which the end seal is provided. The end seal according to claim 7, characterized in that it further comprises that the glue is wrapped around the core and an outer peripheral surface of the glue around the core that includes an additional sealing strip having means or elements sensitive to the electrical stimulation thereon, to heat the strip, such that the outer peripheral glue surface is attached to a splice closure box to which the seal of the end to be placed is provided. 20. A cable end seal, characterized in that it comprises: a body including a core portion "or central portion attached to a rear portion or tail portion, extended, the core portion having an outer peripheral surface and spaced ends, the peripheral surface includes a plurality of cylindrical openings through which the core portion extends between the ends, an edge of each opening communicates with the outer peripheral surface of the core portion to define an entry slot for each opening a cable extending through at least one of the openings; the tail portion is flexible "and has opposite ends, a first of the opposite ends of the tail is integral with and extends tangentially from the outer peripheral surface of the core portion and has a 5 sufficient length to wrap around the peripheral surface of the core portion in connection therewith to cover the entrance slot of each opening and a cable therein, a second free end of the tail is tapered to a reduced thickness; and 10 means or elements extending along the splice between the tail and core portions and along an annular surface of each cylindrical opening, the means I | or elements are sensitive to electrical stimulation to heat the adjacent material for the body connection and each cable thereon in a sealed unit. 21. A cable end seal, characterized in that it comprises: a body including a portion of the core or central portion attached to a rear portion or portion of tail, extended; the core portion has an outer peripheral surface and spaced ends, the peripheral surface includes a plurality of cylindrical openings through the portion of the core extending between the 25 ends, one edge of each opening communicates with the external peripheral surface of the core portion to define an entry slot for each opening; a cable extending through at least one of the openings; a sealing plug in at least one of the openings; the tail portion is flexible and has opposite ends, a first of the opposite ends of the tail is integral with and extends tangentially from the outer peripheral surface of the core portion and is of sufficient length to wrap around the peripheral surface of the core portion. the core portion spliced therewith to cover the entry slot of each opening and each cable therein, a second free end of the tail being tapered to a reduced thickness; a sealing strip extending along the splice between the tail and core portions and between an annular surface of each cylindrical opening and each cable therein; and means or elements in the strip sensitive to electrical stimulation to heat the sealing strip for the connection of each cable and the body in a sealed unit.