Bell Telephone Laboratories

At&t Technologies, Inc.

At&t Bell Laboratories

Western Electric Company, Inc.

American Telephone & Telegraph Co., At&t Bell Laboratories

Nicholas J Cogelia

Candido J Arroyo

Ralph J Darsey

William C Reed

Palmer D Thomas

Carla G Wilson

Brian D Johnson

An aerial service wire (20) includes a jacket (40) having a generally rectangularly shaped cross section and comprising a polyvinyl chloride plastic material. Enclosed by the jacket are two strength members (36--36) each of which includes a plurality of filaments and each of which is impregnated with a material which is compatable with that of the jacket. The strength members are disposed along an axis (42) of the cross section which passes through a geometric center through which a longitudinal axis (50) of the jacket passes. Conductors (30--30) which are individually insulated are disposed adjacent to the longitudinal axis with each strength member being disposed between the conductors and the outer surface of the jacket.

Communications transmission media

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.

Flame-resistant plenum cable and methods of making

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.

Non-shielded, fire-resistant plenum cable

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.

Methods of making cable having superior resistance to flame spread and

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.

Cable having superior resistance to flame spread and smoke evolution

A self-locking cable guard for mechanically protecting an aerial cable from damage by squirrels and other animals comprises a longitudinally elongated body having an inverted-V cross section with the legs of the V bent inwardly toward each other to form bent leg sections so as to define a substantially enclosed cavity for receiving and locking onto the aerial cable. The bent leg sections are specifically configured and spaced apart by a predetermined distance to define an expandable resilient spaced gap which facilitates snap-on installation of the guard and at the same time prevents access to the enclosed cable by a squirrel's jaws.

Growing community of inventors

Duluth, GA, United States of America

Nicholas J Cogelia