Abstract: The invention concerns a method for producing a coaxial cable intended for the transmission of very high frequency signals. This coaxial cable comprises a dielectric insulating layer composed of foamed polytetrafluoroethylene or a composition comprising at least 80% of this product named hereinafter COMPOUND. The layer of insulating material is directly obtained by cold extrusion of a COMPOUND powder, the intimate mixing of a pore-forming agent and a foaming agent and a lubricating oil. The mixing of the COMPOUND powder, the pore-forming and foaming agents is effected dry or in aqueous dispersion. Principal application: Fields of use of ultra-high frequencies such as radars and transmissions.

Abstract: An article comprising a generally axially extending outer, tubular member, a plurality of generally axially extending cylindrical members, and a heat expandable foam sealing member. The outer tubular member has at least one opening and occupies a predetermined volume. Each of the cylindrical members is received by outer tubular member in an axially extending, parallel fashion such that the cylindrical members occupy a volume that is less than the volume of the outer tubular member. The sealing member, capable of sealing the opening of outer tubular member, occupies a volume that is generally equal to the difference between the volume of the outer tubular member and the volume of the cylindrical members.

Abstract: High strength, flexible compositions with improved mechanical properties at elevated temperatures for wire insulation coatings and other shaped articles used in hostile environments are disclosed, consisting of a high temperature fluorocarbon polymer, such as an ethylene-tetrafluoroethylene copolymer or the like, and from about 1% wt. to about 50% wt. of a polyvinylidene fluoride compound.

Abstract: A low attenuation high frequency coaxial cable is provided for carrying microwave energy in the gigaHertz range. A center conductor is wrapped with a plurality of layers of low density PTFE dielectric material. At least one layer of high density unsintered PTFE dielectric material is tightly wrapped around the low density tape with overlapping edges and then is sintered for forming an envelope strong enough to hold the low density material in position during the remainder of the cable preparation and during an attaching of terminating connectors. An outer conductor of longitudinally extending, parallel, adjacent electrically conductive wire strands is applied with a slight helical lay around the dielectric of the cable along its axis thereof surrounding the high density tape. A serving may be applied over the longitudinal wire strands and a jacket applied around the cable over the serving. The cable so formed provides an improvement in performance.

Abstract: Insulated electrical conductor for telecommunications cable in which two layers of insulation are provided. The inner of the two layers is a solid non-cellular construction and the outer layer is cellular. The nominal mutual capacitance between the conductor and an identical conductor is at a desired nominal value of 83 nanofarads/mile value between conductors above a desired minimum value while having an outside diameter across the insulation which is less than for a conductor of the same gauge which provides the same mutual capacitance and has a solid insulation of the same material as the inner layer.

Abstract: A method of making an electrical cable in which an inner electrical conductor is loosely carried within the interior of an outer sheath. The inner conductor has a length in excess of the length of the sheath such that the cable is better able to withstand stretching and bending without damage to the inner electrical conductor.

Abstract: Foamed polymers having low loss at microwave frequencies are prepared through use of perfluorinated alkane foaming agents. The invention is particularly valuable for polymers which are melt-processed at high temperatures, especially fluoropolymers such as tetrafluoroethylene copolymers. The polymeric foams are particularly useful as electrical insulation, especially for coaxial cables suitable for use at microwave frequencies.

Abstract: Foamable hot-melt adhesives comprised of a per se known hot-melt adhesive having a foaming additive therein, for example an organic azo compound. These adhesives can function in a purely physical foaming manner but can also function as crosslinking material, i.e. as solidifying and bonding materials. The foamable hot-melt adhesives of the invention can be used, for example, in sealing cable ends, for filling any desired aperture in the construction field, for sealing windows, doors, etc. or for sealing articles of manufacture.

Abstract: A process for producing a highly expanded polyolefin insulated cable comprising the steps of feeding a compound of polyolefin, nucleating agent and volatile liquid to an extruder, heat extruding said compound through said extruder onto an inner conductor passing through said extruder to cover the outer periphery of said inner conductor thereby forming an insulation layer of highly expanded polyolefin foam having a foaming ratio in excess of 2.5 times (60% expansion degree) tightly adhered to said inner conductor.

Abstract: An insulated transmission medium for propagating ultrasonic vibrational waves and conducting electromagnetic energy in a multiplex type communication system, whereby said medium is a metallic strip that interconnects an ultrasonic wave transmitting transducer, a D.C. power source, an ultrasonic wave receiving transducer and the controlled loads.

Abstract: An improved multiconductor ribbon cable the conductors having at least two layers of polytetrafluoroethylene (PTFE) insulation, a porous unsintered inner layer, that is, the one closest to the conductors, and an impermeable sintered outer layer. Webs of impermeable sintered PTFE connect the insulated conductors. The process for manufacturing the cable includes embedding the conductors between inner sheets of expanded unsintered PTFE and outer sheets of extruded unsintered PTFE, then compressing the sheets only in the web region to high density, and sintering the webs plus the outer insulation layer.

Abstract: An insulated transmission medium for propagating ultrasonic vibrational waves and conducting electromagnetic energy in a multiplex type communication system, whereby said medium is a metallic strip that interconnects an ultrasonic wave transmitting transducer, a D.C. power source, an ultrasonic wave receiving transducer and the controlled loads.

Abstract: A cable of this invention includes a number of pulp-insulated conductor pairs per unit of cable cross-sectional area which is substantially greater than in prior art cables. Each pulp-insulated conductor includes a metallic conductor enclosed in a composite insulation cover which has a controlled dielectric constant and a controlled adhesion of the cover to the conductor. The composite cover comprises a pulpous material and a layer of adhesive material which is interposed between the conductor and the pulpous material. The layer of the adhesive material bonds the pulpous material to the conductor and allows a reduced thickness of pulpous material without degrading the transmission characteristics of the cable. Also, the mechanical integrity of the insulation cover permits the moisture content of the pulpous material to be reduced and the density increased over that achieved in prior art pulp-insulated conductors without causing bare spots in the insulation.

Abstract: An improved flat cable in which parallel, spaced conductors are embedded in an expanded, porous polytetrafluoroethylene insulation and then placed between layers of polytetrafluoroethylene having a higher dielectric constant than the porous insulation. The dielectric constant between conductors can be varied.

Abstract: A cable which is suitable for use as a riser cable in buildings comprises a plurality of conductors each of which is covered with a composite insulation. The composite insulation comprises an inner layer of an expanded polyethylene material and an outer layer of a polyvinyl chloride material with the percent expansion of the inner layer and the thickness of the outer layer being such as to optimize several cable parameters. The resultant cable is one which has excellent fire-retardant properties such as, for example, an unusually low fuel content. Advantageously, this same cable lends itself to color coding for inside wiring and is capable of having a relatively high pair count density. All these parameters are optimized within the framework of specific transmission requirements.

Abstract: A low loss buoyant coaxial cable has its buoyant material placed between conductors to allow for maximum cable cross section for electrical transmission. In addition the strength members are placed radially inward of the center conductor to reduce wearing of the strength members and keeping the electrical performance independent of the electrical properties of the strength members. An alternate embodiment has buoyant material centrally located and the strength members placed with buoyant material between the coaxial conductors.

Abstract: An improved foamable dielectric composition comprising a melt extrudable perfluorocarbon resin containing therein (i) a polytetrafluoroethylene (PTFE) nucleating agent and (ii) a volatile blowing agent, preferably a lower fluorocarbon blowing agent having only one or two carbon atoms; a process for forming such a composition; and, products produced therewith. More specifically, a foamed melt extudable fluorinated ethylene-propylene (FEP) polymer containing therein a PTFE nucleating agent and blown to a foamed structure by means of a volatile fluid--e.g., a lower fluorocarbon such as fluoromethane or, preferably, fluoroethane, a process for forming such a foamed composition; and, products produced therewith such as jacketed electrical conductors and/or coaxial cables wherein at least one conductor is bonded to such a foamed melt extrudable resin.

Abstract: A process for producing a highly expanded polyolefin insulated cable comprising the steps of feeding a compound of polyolefin, nucleating agent and volatile liquid to an extruder, heat extruding said compound through said extruder onto an inner conductor passing through said extruder to cover the outer periphery of said inner conductor thereby forming an insulation layer of highly expanded polyolefin foam having a foaming ratio in excess of 2.5 times (60% expansion degree) tightly adhered to said inner conductor.

Abstract: A dielectric system for coaxial electrical conductors is provided. The dielectric system separates an inner and an outer conductor and is composed of a first layer of cellular polyparabanic acid. This layer directly contacts and provides a continuous skin circumferentially surrounding the inner conductor along its length. A second layer, consisting of a crosslinkable polymeric lacquer which provides a continuous skin enclosing the first layer is also provided. The dielectric system is used in coax cables.

Abstract: An insulated wire having a controlled specific gravity is provided. The wire is manufactured by surrounding an electrical conductor with a layer or a closed cell foam and a sheath. The density and outer diameter of the layer of closed cell foam are controlled to provide the desired overall specific gravity of the insulated wire so that the insulated wire will float on the interface between two immiscible fluids which have different specific gravities.

Abstract: A multipair telephone cable (50) has been specifically developed for voice frequency and T1 carrier frequency transmission between cities. The copper wire gauge, dielectric diameter, and insulation expansion are uniquely designed so that this single cable design can be used for either air core or waterproof versions of the cable. Advantageously, both cable versions are compatible with existing carrier and voice frequency electronics. Also, the load coil spacing for voice frequency transmission and the regenerative repeater spacing for carrier transmission coincide in both versions.

Abstract: There is provided an improved electrical signal transmission cable having at least one signal-carrying center conductor and respective flanking ground conductors. The center conductor is surrounded by a thin layer of polymeric foam insulation. The foam insulated center conductor and the ground conductors are embedded in a solid polymeric insulation. This construction provides for an increased signal propagation velocity as well as for the maintenance of center-to-center distances for the conductors both during the manufacture of and normal use of the cable.

Abstract: A plastic pipe of a thermoplastic material, such as polyvinylchloride provided on its outside with a resilient sealing body of a polyurethane foam plastic, which has been foamed onto said outside and a layer of thermosetting resin with electrically conducting particles being between said body and the plastic pipe in order to ensure a proper conduction, the foam plastic body having a closed surface being integral with the foam plastic body.

Abstract: Capacitance unbalance-to-ground between conductors of a twisted pair, each of which may be insulated with at least a layer of cellular plastic insulation, is maintained within acceptable limits by controlling the extrusion of the insulation to maintain the measured coaxial capacitance and associated outside diameter of the insulated conductors within a range of values which correspond to acceptable capacitance unbalance-to-ground values.

Abstract: This cable for high-voltage, alternating current power transmission cables not only reduces the access of moisture into the cable but reduces access of moisture to the inner face of the insulation to such an extent as to make the cable highly resistant to the formation of electrochemical trees in the solid extruded insulation of the cable. A compressible layer of closed cell, foamed plastic is extruded over the outside surface of the insulation; and a metallic shield fits tightly around the compressible layer, the metallic shield being a longitudinally folded tape with a lap seam which is preferably bonded to prevent ingress of air or other fluid into the cable. If the conductor is stranded, sealant is used to prevent ingress of moisture, or of air, and the humidity it contains into the cable at cable ends.

Abstract: Disclosed is a coaxial cable having greatly improved mechanical and electrical properties derived from a foamed dielectric having a dielectric constant in the range of 1.32 to 1.1, a density between 0.1 and 0.29 grams per cubic centimeter, said foamed dielectric having dispersed throughout it undecomposed particles of a nucleating agent such cable being provided by a novel method of coating a center conductor of the cable with a dielectric with an extruded cellular polyolefin base composition which has been rendered cellular by the direct injection of a blowing agent in a liquid form into the polymer during an extrusion process.

Abstract: A multipair telephone cable especially designed to carry interoffice traffic consists of copper conductors insulated with expanded plastic with or without a solid plastic skin. The copper gauge size, insulation expansion factor and dielectric diameter are uniquely designed to consume a minimum of cable cross-section area while permitting use of the cable to provide voice frequency circuits in a manner comparable to normal; 24-gauge cable as well as to provide carrier frequency circuits operating in the range of from about 100 kHz to 8.0 MHz comparably to normal 22-gauge cable. The cable includes pairs twisted according to a constant twist frequency spacing concept.

Abstract: Disclosure is made of a universally fitting electrical insulator for mounting between the armature shaft and the windings and laminations of an armature. The disclosure is also of a method for mounting the insulator in the armature. The insulator and method are particularly useful in the production of double insulated electrical hand tools.

Abstract: Disclosure is made of a novel sheath and the method of its use for protecting electrical conductors and connections. The sheath comprises a tubular body which defines an interior space. The space contains an expandable, synthetic, polymeric resin foam forming composition. The method of the invention comprises inserting an electrical conductor or connection into the sheath of the invention and activating the foam forming composition to foam and encapsulate the conductor or connection. The installed sheaths protect the conductors and/or connections from degradation by environmental conditions, are resilient and improve the insulative quality of the electrical connection.

Abstract: A coaxial cable having improved mechanical and electrical properties comprising an inner conductor; an outer inert gas blown cellular ethylene or propylene polymer dielectric layer having in unexpanded form a density of about 0.86 to 0.96 grams per cubic centimeter, a melt index of about 0.05 to 10 decigrams per minute and an expanded density up to 0.6 grams per cubic centimeter, said core member having a dissipation factor value of .ltoreq. 250 microradians at an electrical transmission frequency range of from 50 to 300 mega Hertz; and an outer coaxial conductor.

Abstract: A cable splice for joining together two or more sections of high voltage cable employs for its primary insulation a rigid, closed-cell foam having a thick integral skin bordering all the external surfaces of the foam and located in regions of the splice where electrical stresses are the highest. The skin has an average density greater than 40 pounds per cubic foot in its outer one-sixteenth inch.

Abstract: A conductor wire is composed of an aluminium alloy consisting of between 98.0 and 99.5 weight percent aluminium; between 0.3 and 1.0, preferably 0.4 to 0.6, weight percent iron; between 0.16 and 1.2, preferably 0.3 to 1.0, weight percent silicon; and trace quantities of conventional impurities. The conductor wire has a higher tensile strength than wires of known aluminium alloys which contain similar quantities of iron and is especially suitable for use in telecommunication cables, wiring cables and overhead conductors. The conductor wire may have a cladding of copper or copper alloy.

Abstract: Nonmetallic-sheathed cable is insulated and jacketed with expanded polyvinyl chloride comprising 8-24%, by volume, of gas.