| 摘要 |
A pushpull cable conduit is made by continuously moving a tubular mandrel through a crosshead extruding die, forming a tape of micro-porous polytetrafluoroethylene resin into cylindrical form covering the mandrel as it enters the extruding die, extruding an outer layer of fluid polymeric material over the cylindrical covering in the presence of heat, helically wrapping contiguous wires over said outer layer to form a wire layer, extruding an outer covering of thermoplastic material over the wire layer, and removing the tubular mandrel. The porosity of the polytetrafluoroethylene covering insures a good heat bond with the outer layer of fluid polymeric material and also provides a lubricant reservoir in its inner surface, thereby minimizing friction with the cable core and greatly reducing sound transmission.
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