Cable Harness Safety Cable Design to Prevent Electrical Line Tear-Out

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Solution Overview

Problem

Electrical signal lines in working devices like blowers and brush cutters are prone to damage from mechanical forces, such as being caught by foreign objects, leading to potential tears at connection points due to their limited mechanical strength.

Innovation Solution

A safety cable is routed parallel to the electrical lines between the operating handle and the drive unit, with one end fixed to the handle and the other to the drive unit, forming a breakaway protection that absorbs lateral forces and prevents the electrical lines from tearing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical lines are routed together with a cable harness on the outside of the blower tube, then the electrical lines are protected from damage, but foreign objects can get caught in the line bundle and impede the operation of the blower tube

Engineering Contradiction:
Improveprotection of electrical linesVSAvoidforeign objects caught in line bundle
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The solution separates the electrical lines from the cable harness by routing them independently along the blower tube. This segmentation prevents foreign objects from catching both components together, while still providing protection for the electrical lines through their own dedicated routing path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrical lines are extracted from the cable harness bundle and routed separately along the blower tube. This extraction eliminates the harmful interaction where foreign objects could snag the bundled lines, while maintaining the protective routing away from the work area.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If electrical lines are routed close to the work area, then they are easier to connect, but high lateral force and tensile force can cause the electrical line to tear at connection points

Engineering Contradiction:
Improveease of connectionVSAvoidresistance to mechanical stress
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

A safety cable is installed in advance alongside the electrical lines, mechanically fixed at both ends. This safety cable acts as a protective element that absorbs lateral and tensile forces before they can reach the electrical lines, preventing tears at connection points while allowing the lines to remain accessible for connection.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The safety cable serves as an intermediary protective element between external forces and the electrical lines. It absorbs and dissipates mechanical stresses through its own strength, protecting the vulnerable electrical lines from direct exposure to high lateral and tensile forces.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If signal lines are used for control functions, then precise control is achieved, but they can only withstand a small amount of mechanical stress

Engineering Contradiction:
Improvecontrol precisionVSAvoidmechanical stress resistance
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The safety cable acts as an intermediary protective structure that bears mechanical stresses, allowing the signal lines to maintain their precise control function without being directly exposed to mechanical stress. The safety cable absorbs forces that would otherwise damage the fragile signal lines.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The safety cable is pre-installed and mechanically fixed to provide cushioning protection before any mechanical stress occurs. This beforehand protection allows the signal lines to operate with high precision while being shielded from mechanical damage by the safety cable's strength.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP4011197B1Working tool with a cable harness between a drive unit and an operating handle
Publication Date: 2023.08.30 ANDREAS STIHL AG & CO KG
  • EP4011197B1 patent drawingFigure 1
  • EP4011197B1 patent drawingFigure 2
  • EP4011197B1 patent drawingFigure 3~4

AI summary

The invention relates to a work device comprising a drive unit (2) and an operating handle (3), wherein the operating handle (3) is connected to the drive unit (2) via several electrical cables (L1, L2, L3, L4). An electrical cable (L1, L2, L3, L4) is connected to the operating handle (3) at a first electrical connection point and to the drive unit (2) at a second electrical connection point. At least some of the electrical cables are bundled together in a cable bundle (L). To prevent the electrical cables from being pulled out, a safety cable (20) is provided, running parallel to the electrical cable (L1, L2, L3, L4) between the operating handle (3) and the drive unit (2). The safety cable (20) is mechanically secured at one end section (21) to the operating handle (3) and at the other end section (22) to the drive unit (2).The electrical conductor (L1, L2, L3, L4) is guided together with the safety cable (20) in such a way that the safety cable (20) forms a breakaway protection for the electrical conductor (L1, L2, L3, L4).