Cable Sheath Lubricant Integration for Friction Reduction
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Solution Overview
Problem
Electrical cables have a high coefficient of friction, making them difficult to install in internal sections of walls and conduits, and existing solutions require additional equipment and materials that alter manufacturing processes and increase costs.
Innovation Solution
Incorporating a lubricant material into the sheath of the cable during the extrusion process, allowing it to be mixed with the sheath material before or after heating, to reduce the cable's coefficient of friction without altering its geometrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If alternative materials such as vaselines are used to coat the cable exterior surface, then the coefficient of friction is reduced, but additional materials and processing steps are required
Solution Approach 1:
The lubricant is incorporated into the sheath material itself, merging the lubrication function with the sheath material. This eliminates the need for separate lubricant application equipment and steps, while still achieving reduced friction during cable installation
Solution Approach 2:
The sheath material contains embedded lubricant that automatically provides lubrication during cable installation without requiring external application. The lubricant is released as the cable is pulled through conduits, providing self-service lubrication
2Ease of operation
If guides of small diameter are used to facilitate cable insertion, then the coefficient of friction is reduced, but additional equipment and installation time are required
Solution Approach 1:
The lubrication function is extracted from separate guide equipment and integrated directly into the cable sheath material. This eliminates the need for separate guide devices and reduces installation time, as the lubricant is already present on the cable surface
3Ease of operation
If additional equipment is interposed between the extruder and cooling vessel to apply lubricant, then the coefficient of friction is reduced, but the manufacturing line is significantly altered and space is occupied
Solution Approach 1:
The lubricant application function is merged with the existing sheath extrusion process. The lubricant is mixed with the sheath material in the extruder, eliminating the need for separate lubricant application equipment between the extruder and cooling vessel
Solution Approach 2:
The sheath extruder is given multiple functions: it both forms the sheath structure and incorporates lubricant into the material. This multi-functionality eliminates the need for dedicated lubricant application equipment in the manufacturing line
4Ease of operation
If additional equipment is used to deposit lubricant on the sheath, then the coefficient of friction is reduced, but control over sheath dimensions is compromised
Solution Approach 1:
The lubricant incorporation is merged with the sheath extrusion process itself. Since the lubricant is mixed with the sheath material before extrusion, the same equipment that controls sheath dimensions also controls lubricant distribution, maintaining precision without compromising friction reduction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The lubricated cable exhibits a significantly reduced coefficient of friction, simplifying installation, reducing the risk of 'burn-through' during pulling, and minimizing jacket damage, while maintaining control over the cable's dimensions and manufacturing efficiency.
Implementation Method 1
the lubricant material is mixed with the sheath material prior to either material being heated
Implementation Method 2
which lubricating material blooms, migrates toward the exterior, or permeates the cable sheath
Data Source
AI summary
Disclosed is a method of manufacturing a finished cable by a process directed to reduce the amount of force required to install the cable. The process involves the extrusion of the cable's outer sheath and the incorporation of a pulling lubricant in connection with, and prior to the completion of, the extrusion to reduce the sheath's surface coefficient of friction as well as reduce the required force to pull the cable for installation. The conductor core is coated with an extruded plastic material with which an appropriate (in amount and type) pulling lubricant is initially combined with the plastic material prior to the formation of the sheath and in which the sheathed conductor core is thereafter cooled, the lubricant either migrating to and/or permeating the sheath to be available at the surface of the sheath at the time of the cable's installation. The preselected lubricant is disclosed as either combined with the plastic material during initial pelletization, or mixed with the plastic pellets prior to introduction of the mixture into the extruding head, or introduced into the extruding head at a separate location downstream from where the plastic material is introduced into the extruding head.