Rotating Knife with Sensing Surface for Cable Sheath Removal

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Solution Overview

Problem

Conventional methods for removing inner sheathing from electrical conductors, particularly multi-core cables with irregularly shaped cross-sections, lack reliability and process safety, and are not suitable for a wide variety of cable types, especially when dealing with twisted strands and positive-locking cutting devices.

Innovation Solution

A device with a knife having a contact surface and a cutting edge, where the blade arm is movably and detachably attached to a magnetized blade wheel, allowing precise guidance along the cable's contour, and a separate trigger mechanism for removing incised foil pieces, combined with an adhesive tape system for pulling off the film and a scraping arrangement for residual removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional cutting devices are used for removing inner sheathing from cables with irregular cross-sections, then the cutting process can be performed, but the reliability and process safety are insufficient and the device cannot handle a wide variety of cable types

Engineering Contradiction:
Improvesuitability for various cable typesVSAvoidreliability and process safety
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The knife arm is designed to be movable relative to the cable axis, allowing dynamic adjustment of the cutting position. The knife can be moved radially inward and outward, and the knife arm itself can rotate independently of the cable, enabling adaptation to irregular cable cross-sections while maintaining reliable cutting contact

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cutting device is segmented into independent components: the rotating blade wheel, the movable knife arm, and the individually controllable knife. This segmentation allows each component to perform its specific function optimally while adapting to different cable geometries, improving both versatility and reliability

Inventive Principle:
Principle #1Segmentation

2Force

If twisted strands with positive-locking cutting devices are used, then the cutting force can be applied, but it is unclear where the strands are and where the spaces between them are

Engineering Contradiction:
Improvecutting force applicationVSAvoidposition identification of strands
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The positive-locking mechanical cutting device is replaced with a rotating blade that applies continuous cutting force. The blade rotates around the cable while the knife arm moves radially, eliminating the need for precise mechanical positioning and making the process independent of strand position identification

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cutting system is self-regulating through the interaction of the rotating blade and movable knife arm. The knife automatically follows the cable's contour and applies cutting force where needed, without requiring external guidance or position identification of the strands

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If a blade arm movably attached to a blade wheel is used, then precise guidance along the cable contour is achieved, but the device complexity increases

Engineering Contradiction:
Improveguidance precision along cable contourVSAvoidstructural complexity of blade assembly
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The blade arm is designed with movable attachment to the blade wheel, allowing it to dynamically adapt to the cable's irregular contour. The knife arm can rotate and move radially, providing precise guidance along complex cable shapes while maintaining a relatively simple mechanical structure through natural motion rather than complex constraints

Inventive Principle:
Principle #15Dynamics

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 solution enhances the reliability and automation of the stripping process, enabling efficient removal of foil from cables with irregular shapes, ensuring the strands are not damaged and all film residues are cleanly removed, while allowing for easy adjustment and adaptation to different cable types.

Implementation Method 1

the blade arm is movably and detachably attached to a magnetized blade wheel

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP3322054B1Apparatus and method for removing an internal envelope from an electrical conductor
Publication Date: 2020.06.03 SCHLEUNIGER AG
  • EP3322054B1 patent drawingFigure 1
  • EP3322054B1 patent drawingFigure 2~4

AI summary

A device for removing the inner sheath of electrical conductors of a preferably multi-core cable comprises at least one holding/clamping device for axially and rotationally clamping the cable and a knife arrangement (1, 21) rotatable about the longitudinal axis of the cable, the knives of which can be subjected to a force towards the cable axis. The at least one knife (24, 26) has a sensing surface (26) provided for bearing on the surface of the inner sheath and directly adjoining a cutting edge (24) projecting beyond this sensing surface (26).