Abstract: A cable closure (20) which is suitable for aerial, pedestal, wall-mounted or buried use and which is suitable for enclosing connections between metallic or optical fiber transmission media includes a base (30) and a cover (32). The base and/or the cover include a plurality of openings through which extend cables. Connections (50) between transmission media of the cables are disposed between portions (51,52) of a superabsorbent compliant foam material. The portions of the foam material and the base and the cover are sized so that when the cover is assembled to the base, the foam material is compressed. Upon contact with water which may enter the closure, the superabsorbent foam material swells, molding about the connections to protect them from the water and expanding outwardly to seal any unintended openings in the housing and prevent the ingress of additional water.

Abstract: An animal-resistant optical fiber cable (20) includes a core (22) which comprises a transmission medium and a sheath system. The sheath system includes an outer jacket (65) and a dielectric armor (40) in the form of a shell. The shell comprises a plurality of longitudinally extending preformed segments (42--42) each being a composite comprising a substrate portion (50) and a layer (52) of a coating material which has a relatively high hardness disposed on an outer surface of the substrate portion. Each of the segments covers less than half of the periphery of the core and, in a preferred embodiment, eight segments are used. Further, the shell segments are stranded helically about the core with at least portions of longitudinal edge surfaces of adjacent segments being in engagement with each other. The shell segments not only provide rodent protection for the cable, but also they provide suitable tensile and compressive strength as well as suitable flexibility and cable bending performance.

Abstract: An animal-resistant optical fiber cable (20) includes a core (22) which comprises a transmission medium and a sheath system. The sheath system includes an outer jacket (65) and a dielectric armor (40) in the form of a shell. The shell comprises a plurality of longitudinally extending preformed segments (42--42) each having a cross section transverse to a longitudinal axis of the cable each of which covers less than half of the periphery of the core. Further, the shell segments are stranded helically about the core with at least portions of longitudinal edge surfaces of adjacent segments being in engagement with each other. The shell segments not only provide rodent protecting for the cable, but also they provide suitable tensile and compressive strength. Further, because the cable in the preferred embodiment has an all-dielectric sheath system, it is inherently lightning, corrosion and EMP resistant.

Abstract: A communications cable (20) comprising a core (22) of at least one transmission media and a plastic jacket (34) includes provisions for preventing the movement of water within the cable. The cable includes a strength system (32) including longitudinally extending fibrous strength members (32-33) having a relatively high modulus and having water blocking provisions. In one embodiment, each fibrous strength member is treated with a superabsorbent liquid material which when dry fills interstices and covers portions of the exterior thereof. In another embodiment, a filamentary strand material comprising a water swellable fibrous material is wrapped about each fibrous strength member.

Abstract: A communications cable comprising a core of transmission media such as optical fibers, for example, disposed in a core tube and a sheath system (32) includes provisions for preventing the movement of water within the cable core. Water blocking provisions (26) are disposed in the core tube and may comprise a tape or a yarn, for example, or both. The tape may comprise substrate tapes between which is disposed a superabsorbent material in powder form which upon contact with water swells and inhibits the further movement of the water. In another embodiment, a water swellable yarn may extend longitudinally linearly with the optical fibers in the core.

Abstract: An animal-resistant optical fiber cable (20) includes a core (22) which comprises a transmission medium and a sheath system. The sheath system includes an outer jacket (65) and a dielectric armor (40) in the form of a shell. The shell comprises a plurality of longitudinally extending preformed segments (42--42) each having an arcuately shaped cross section transverse to a longitudinal axis of the cable and each comprising glass fibers embedded in a matrix material. Each of the segments covers less than half of the periphery of the core and, in a preferred embodiment, eight segments are used. Further, the shell segments are stranded helically about the core with longitudinal edge surfaces of adjacent segments being in engagement with each other. The shell segments not only provide rodent protection for the cable, but also they provide suitable tensile and compressive strength. Further, because the cable has an all-dielectric sheath system, it is inherently lightning, corrosion and EMP resistant.

Abstract: A communications cable comprising a core of at least one transmission medium and a plastic jacket includes provisions for preventing the movement of water within the cable. An impregnated tape (35) is interposed between the core and the jacket and is wrapped about the core to form a longitudinal overlapped seam. The tape comprises a substrate tape (37) which is impregnated with a superabsorbent material which upon contact with water swells and inhibits the further movement of the water. The tape and its thickness are controlled so that the thickness is minimal while the tensile strength of the tape and its porosity prior to impregnation are optimized.

Abstract: A flame and smoke resistant optical fiber cable (20) having a relatively small diameter includes a core comprising a ribbon array or a plurality of individual fibers and a sheath system. The sheath system includes an impregnated fiber glass tape (35) which has been wrapped about the core. The tape is impregnated with a solution system which comprises a micaceous constituent, a fluoropolymer constituent and a lubricant such as silicone. The impregnated system provides the tape and hence the cable with unexpectedly superior fire retardant and smoke resistance properties so that the cable is suitable for plenum and riser use. Advantageously, the thickness of the tape impregnated with such a system is relatively thin which is helpful in maintaining a relatively small diameter for the cable. An all dielectric strength member system is disposed between the tape and a plastic jacket (37).

Abstract: A communications cable comprising a core of at least one transmission media and a plastic jacket includes provisions for preventing the movement of water within the cable. A water blockable yarn (33) or strip (35) is interposed between the core and the jacket (32) and extends either linearly along the cable or is wrapped helically about a portion of the sheath system. In any plane along the cable which is transverse to the longitudinal axis of the cable, the yarn or the strip extends about an insubstantial portion of an inner periphery of the cable. As a result, any desired bond between the jacket and an underlying element of the cable sheath system is discontinuous for only an insignificant portion of the peripheral surface of contact. The yarn may be one which has been treated with a superabsorbent material whereas the strip may comprise a substrate strip which has been impregnated with a superabsorbent material which upon contact with water swells and inhibits the movement of water within the cable.

Abstract: An optical fiber cable includes a fluted strength member core (22) which comprises a plurality of ribs (26--26) extending radially from a center portion and a plurality of grooves (28--28), each groove being disposed between two adjacent ribs. The fluted core is such that the ratio of the diameter of a circle (41) which passes through an outermost surface of each rib to the diameter of a circle (44) through the inverts of the grooves does not exceed a predetermined value and cooperates with a reference width of each rib to allow a plurality of optical fibers to be disposed in each groove. Further, the geometry of the fluted core is such that the optical fibers are capable of longitudinal and lateral movement in the grooves. A core wrap (50) which may be made of a flame retardant material encloses the fluted core and a jacket (60) which is made of a plastic material encloses the core wrap.

Abstract: An optical fiber cable particularly suited for use in building distribution systems includes a core which comprises a plurality of coated optical fibers (22--22) with each being enclosed in a plastic buffer (26). The optical fibers are individually or collectively enclosed in a fibrous strength member. Over the strength member in each of several embodiments is provided an outer jacket comprising a plastic material having excellent resistance to flame spread and smoke evolution. The plastic material comprising the jacket is disposed about the strength member and decoupled sufficiently therefrom to avoid the introduction of microbending stresses in the optical fiber. This may be accomplished by vacuum sizing the plastic material which has been tubed over an advancing optical fiber core as the plastic material is being drawn down onto the strength member.

Abstract: An optical fiber cable includes a core (22) comprising at least one optical fiber, a plastic tubular member (28) which encloses the core, a jacket (54) which encloses the tubular member and a prefabricated strength system which is interposed between the jacket and the tubular member. The strength system includes a carrier tape (82) which may be comprised of woven glass or impregnated woven glass, for example, and which is wrapped longitudinally about the tubular member. The carrier tape has an adhesive material disposed on one surface thereof for causing a plurality of longitudinally extending strength members (86--86) to remain attached to the tape while the jacket is being extruded over the strength system. In one embodiment, a metallic shield system (52) is disposed about the tubular member and the prefabricated strength system is disposed in engagement with an outer surface of the shield system.

Abstract: A relatively small pair size cable (20) comprising at least one conductor (22) which is insulated with polyvinyl chloride plastic material is provided with a flame retardant, smoke suppressive sheath system (30). The sheath system has a relatively low thermal conductivity and provides a predetermined delay prior to the thermal decomposition of the conductor insulation. It includes a layer (31) of an impregnated woven glass material which has an air permeability that is sufficiently low to minimize gaseous flow through the layer of woven glass material and to delay heat transfer to the core for a predetermined time. The woven glass layer is wrapped about the core to have a longitudinal overlapped seam and is enclosed by an outer jacket (40) of a fluoropolymer plastic material which is extruded about the woven layer.

Abstract: A relatively small pair size cable (20) comprising at least one conductor (22) which is insulated with polyvinyl chloride plastic material is provided with a flame retardant, smoke suppressive non-metallic sheath system (30). The sheath system has a relatively low thermal conductivity and provides a predetermined delay prior to the thermal decomposition of the conductor insulation. It includes an inner layer (31) of an aramid fibrous material which has a relatively high compressibility, a relatively low heat absorptivity, and a relatively low air permeability. The inner layer is enclosed by an outer jacket (40) of a fluoropolymer plastic material which is extruded about the inner layer.

Abstract: A relatively small pair size cable (20) comprising at least one insulated conductor (22) is provided with a flame retardant, smoke suppressive non-metallic sheath system (30). The sheath system has a relatively low thermal conductivity and provides a predetermined delay prior to the thermal decomposition of the conductor insulation. It includes an inner layer (31) of an inorganic cellular material which has a relatively low air permeability and two tapes (41, 42) which are wrapped helically about the inner layer with overlapped sealed seams. Each tape comprises a flame retardant thermosetting material. In an alternative embodiment, the heat absorptivity of the sheath system is increased substantially to facilitate the sealing of the seams as the cable is moved along a manufacturing line. This may be accomplished by using an inorganic cellular material which has a relatively high absorptivity or by facing the inner layer or one of the tapes with a material which is heat absorptive.

Abstract: A method of making a cable (20) specially suited for use in building plenums because of its low flame spread and smoke evolution includes enclosing a multiconductor core (22) in a sheath comprising an inorganic, cellular core wrap (31), a corrugated metallic barrier (40) and dual layers (51) and (52) of a polyimide tape. The tapes are wrapped helically about the barrier in a manner that avoids a compression of the core wrap. The sheath is effective to resist heat transfer inwardly toward the core by conduction while the metallic barrier reflects radiant heat. Advantageously, the sheath containerizes the core without unduly compressing it and thereby allows the intumescence of conductor insulation during a fire to form char which is effective to suppress the evolution of smoke and the propagation of flame.

Abstract: A cable (20) specially suited for use in building plenums because of its low flame spread and smoke evolution includes a multiconductor core (22) which is enclosed in a sheath comprising an inorganic, cellular core wrap (31), a corrugated metallic barrier (40) and dual layers (51) and (52) of a polyimide tape which are wrapped helically about the barrier in a manner that avoids a compression of the core wrap. The sheath is effective to resist heat transfer inwardly toward the core by conduction while the metallic barrier reflects radiant heat. Advantageously, the sheath containerizes the core without unduly compressing it and thereby allows the intumescence of conductor insulation during a fire to form char which is effective to suppress the evolution of smoke and the propagation of flame.