Electric Hand Tool Cable Kink Protection

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Solution Overview

Problem

Existing electric hand-held power tools face issues with cable kink protection due to a clip connection between the joint and sleeve parts, which can lead to slippage and failure to prevent buckling.

Innovation Solution

The sleeve part is injection molded onto the joint part with an undercut, creating a form fit that securely connects the two components, allowing for a flexible grommet and enhanced force absorption, and the joint part is designed with a rounded shell for limited movement within the device housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a clip connection is used to connect the joint part and sleeve part, then the cable kink protection can be assembled, but the connection is unreliable and the grommet part can slip

Engineering Contradiction:
Improveconnection reliabilityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The joint part and sleeve part are merged into a single integrated component through injection molding. The sleeve part is molded directly onto the joint part, creating a unified structure that eliminates the separate clip connection and prevents slippage between components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sleeve part is nested onto the joint part through injection molding, with the sleeve part forming an undercut that interlocks with the joint part geometry. This nested structure ensures the sleeve part cannot slip off while maintaining a compact design.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If a rigid connection is used between joint part and sleeve part, then connection stability is improved, but cable flexibility is reduced

Engineering Contradiction:
Improveconnection stabilityVSAvoidcable routing flexibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The integrated structure features local flexibility through the undercut geometry and material selection. The sleeve part can deform locally to accommodate cable movement while the overall connection remains stable. The rounded shell design also provides localized flexibility for pivotable movement.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sleeve part is designed as a flexible component that can deform to accommodate cable routing changes. The material and geometry allow the sleeve to bend and flex while maintaining its protective function and connection stability.

Inventive Principle:
Principle #30Flexible shells and thin films

3Object-affected harmful factors

If the joint part has a rounded shell for limited movement, then cable twisting is reduced, but the structure becomes more complex

Engineering Contradiction:
Improvecable damage from twistingVSAvoidjoint part geometry complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The joint part features a rounded shell with spherical or dome-shaped internal cavities. This curved geometry allows the joint part to pivot and rotate smoothly within the device housing, reducing cable twisting while maintaining a simple overall structure that integrates well with the housing.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This solution provides reliable cable protection against kinking and buckling by ensuring a secure connection and flexible routing, while also preventing damage from sharp edges and allowing for pivotable movement within the device housing.

Implementation Method 1

the second plastic component of the grommet part is injection molded onto the first plastic component of the articulation part

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 2

the injection molded grommet part and the articulation part form an undercut, so that there is also a form fit between the grommet part and articulation part in the direction of the cable

Methodology Applied
Scientific EffectForm fit:

Implementation Method 3

the articulated part can be moved to a limited extent in the device housing by means of the rounded shell on the outside, without tilting there

Methodology Applied
Scientific EffectPivoting movement:

Implementation Method 4

the inside of the shell of the joint part, which is rounded on the outside, is also rounded at least in certain areas. In particular, it follows a spherical or dome shape. It is particularly advantageous that the rounded inside of the shell of the articulated part means that there are no sharp edges, so that the articulated part is prevented from cutting into the grommet part

Methodology Applied
Scientific EffectRounded geometry:

Implementation Method 5

guide means are arranged between the cable kink protection and the device housing, so that the cable kink protection is held in the device housing so that it can move to a limited extent, in particular pivot to a limited extent

Methodology Applied
Scientific EffectGuided movement:

Data Source

PatentEP2020277B1Electric hand tool
Publication Date: 2010.02.24 METABOWERKE
  • EP2020277B1 patent drawingFigure 1~4

AI summary

The cable has a cable break protection (2) leading through a cable from housing, movably held relative to the housing in a limited manner, and including a hinge (4) made of plastic component and a protective sleeve part (6) made of another plastic component. The plastic component of the sleeve part is extruded by the plastic component of the hinge. The plastic component of the hinge includes hard component i.e. Polyamide 6, and the plastic component of the sleeve part includes soft component e.g. PVC or triphenyl methane (TPM). The extruded sleeve part and the hinge forms an under cut.