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AssigneeSouthwire Company
InventorsTerry Chambers, Randy D. Kummer, John W Armstrong, Philip Sasse, David Reece, Hai Lam
Estimating the term…
Disclosed is type THHN cable having a reduced surface coefficient of friction, and the method of manufacture thereof, in which the central conductor core and insulating layer are surrounded by a nylon sheath. A high viscosity, high molecular weight silicone based pulling lubricant for THHN cable, or alternatively, erucamide or stearyl erucamide for small THHN gauge wire, is incorporated, by alternate methods, with the nylon material from which the outer sheath is extruded, and is effective to reduce the required pulling force on the cable during installation.
In a power cable of the type comprising a conductor and sheath surrounding said conductor, in which the sheath has at least its exterior portion formed of nylon material, an improvement in which a erucamide pulling lubricant is introduced in said material during the manufacture of the cable, and either permeates throughout, or migrates through, at least said exterior portion of the sheath to be available at the exterior surface of said sheath as said power cable is pulled along an installation surface through building passageways in rafters or joists or conduit bends, and in a concentration sufficient to reduce the required installation pulling force for installation of the cable through building passageways in rafters or joists or conduit bends.
In a method for manufacturing a power cable of the type comprising a conductor and an extruded sheath surrounding at least said conductor, in which the sheath has at least its exterior portion formed of nylon material, the improvement in which a silicone based pulling lubricant is introduced in said material in connection with a process of extrusion of the sheath as one of the steps for the overall manufacture of the cable, which lubricant after such introduction permeates throughout at least said exterior portion of the sheath, thereby to become available at the exterior surface of said sheath to facilitate the installation of said cable to be pulled along an installation surface through building passageways in rafters or joists or conduit bends, the lubricant being in a concentration sufficient to reduce the required installation pulling force for installation of said cable through said building passageways.
An improved process of manufacturing a finished power cable assembly of the type comprising a central conductor and a surrounding sheath of at least one outer layer of nylon material defining the exterior surface of the finished cable, said process comprising:
In a method for manufacturing a lubricated power cable of the type comprising a conductor and an extruded sheath surrounding at least said conductor, in which the sheath has at least its exterior portion formed of nylon material, the improvement in which a pulling lubricant is introduced in said material in connection with a process for extrusion of the sheath, which pulling lubricant after such introduction becomes available at at least the exterior surface of said sheath to facilitate such lubricated cable to be pulled along an installation surface through building passageways in rafters or joists or conduit bends, the lubricant being in a concentration sufficient to reduce the required installation pulling force, for installation of the lubricated cable through said building passageways, from an installation pulling force required to install, through said passageways, cable of the same type and size, but having essentially no lubrication at said exterior portion, wherein the required installation pulling forces correspond to those which would be measured by pulling the said cable through test apparatus incorporating an arrangement of PVC conduit that is sized to accommodate the cable having an initial 10 foot straight section of conduit, followed by a 90° bend having a left-orientation, followed by a first 90° bend having a right-orientation, followed by a 30 foot straight section of conduit, followed by a second 90° bend having a right-orientation, followed by a 5 foot straight section of conduit, followed by a third 90° bend having a right-orientation, followed by a 10 foot straight section of conduit.
In a method for manufacturing a lubricated power cable of the type comprising a conductor and an extruded sheath surrounding at least said conductor, in which the sheath has at least its exterior portion formed of nylon material, the improvement in which a pulling lubricant is introduced in said nylon material in connection with a process for extrusion of the sheath, which pulling lubricant after such introduction becomes available at at least the exterior surface of said sheath to facilitate such lubricated cable to be pulled along an installation surface through building passageways in rafters or joists or conduit bends, the lubricant being in a concentration sufficient to reduce the required installation pulling force, for installation of the lubricated cable through said building passageways, of a quantifiable reduction of at least about 50% of the required installation pulling force to install, through said passageways, cable of the same type and size as said lubricated cable, but having essentially no lubrication at said exterior portion, wherein the respective required installation pulling forces correspond to those which would be measured by pulling the said cable through test apparatus incorporating an arrangement of conduit (i) constructed of a PVC conduit that is sized to accommodate said power cable, and (ii) comprising a first conduit segment of about 10 feet separated from a second conduit segment of about 30 feet by two 90° bends, the second conduit segment separated from a third conduit segment of about 5 feet by a 90° bend, and the third conduit segment separated from a fourth conduit segment of about 10 feet by another 90° bend.
In a method for manufacturing a lubricated power cable of the type comprising a conductor and an extruded sheath surrounding at least said conductor, in which the sheath has at least its exterior portion formed of nylon material, the improvement in which a pulling lubricant is introduced in said material in connection with a process for extrusion of the sheath, which lubricant after such introduction becomes available at at least the exterior surface of said sheath to facilitate such cable to be pulled along an installation surface through building passageways in rafters or joists or conduit bends, the lubricant being in a concentration sufficient to reduce the required installation pulling force, for installation of said lubricated cable through said building passageways, a quantifiable reduction of up to about 75% of the required installation pulling force to install, through said passageways, cable of the same type and size as said lubricated cable, but having essentially no lubrication at said exterior portion, the respective required installation pulling forces corresponding to those which would be measured by pulling the said cable through test apparatus incorporating an arrangement of conduit (i) constructed of a PVC conduit that is sized to accommodate said cable, and (ii) comprising a first conduit segment of about 10 feet separated from a second conduit segment of about 30 feet by two 90° bends, the second conduit segment separated from a third conduit segment of about 5 feet by a 90° bend, and the third conduit segment separated from a fourth conduit segment of about 10 feet by another 90° bend.
Dependencies are inferred from the claim text.