Foamed Cable for Hand Tool Wiring

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Solution Overview

Problem

Existing hand tools with vibration-reducing mechanisms in the connection area between the handle and main housings often suffer from damaged cabling due to loose strands rubbing against each other or the housing, especially when drilling dust is present, leading to tool failure.

Innovation Solution

Embedding the strands in a foamed protective sheath to prevent friction and damage, allowing for parallel arrangement and stretchable design to accommodate movement and provide protection for both wires and electronic components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If strands are arranged loosely in the connection area, then assembly is simpler, but strands rub against each other and housing causing damage

Engineering Contradiction:
Improveassembly simplicityVSAvoidcabling durability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Multiple loose strands are merged into a single integrated cable assembly with a common protective sheath. This combines previously separate components into one unit that is easier to handle and assemble while preventing internal friction between strands through the enclosing sheath structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

A protective sheath is introduced as an intermediary element between the strands and the external environment. This sheath mediates the interaction by providing a friction-reducing interface that prevents strands from rubbing against each other and against the housing during relative movements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If strands are fixed together in a protective sheath, then friction damage is prevented, but flexibility to accommodate movement is reduced

Engineering Contradiction:
Improvecabling protectionVSAvoidmovement accommodation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The protective sheath is designed as a flexible structure that can deform and stretch to accommodate the relative movements between handle housing and main housing. This flexible shell maintains strand protection while adapting to dynamic operational conditions without causing damage.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The cable assembly incorporates dynamic characteristics through its flexible sheath design that allows for movement and deformation during operation. The structure transitions from a static fixed arrangement to a dynamic system that can adapt its configuration based on operational demands while maintaining protective functions.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If multiple strands are handled separately, then routing is more flexible, but assembly complexity increases

Engineering Contradiction:
Improverouting flexibilityVSAvoidassembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple strands that would otherwise require separate routing and assembly operations are merged into a single pre-assembled cable unit. This merging reduces the number of assembly steps and complexity while the flexible sheath design maintains the ability to accommodate various routing requirements.

Inventive Principle:
Principle #5Merging (Combining)

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 foamed protective sheath effectively prevents strand damage from friction and jamming, simplifies assembly, and provides flexibility to accommodate relative movements, reducing the risk of electrical connection failure during operation.

Implementation Method 1

the strands are embedded in a foamed protective sheath in such a way that they are largely fixed to one another. This prevents the two strands from rubbing against each other and causing damage

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

Such a protective jacket made of foamed material can effectively prevent damage to the strands caused by friction, and the protective jacket can also be made sufficiently stiff to prevent the cabling from jamming

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP1787760B1Hand tool with foamed cable
Publication Date: 2010.02.24 HILTI AG
  • EP1787760B1 patent drawingFigure 1
  • EP1787760B1 patent drawingFigure 2
  • EP1787760B1 patent drawingFigure 3

AI summary

The device has a main housing (10), in which an electric motor (12) is placed. A handle housing (6) is movably held against the main housing in a spatial direction. A motor switch (16) is provided in the handle housing and is electrically connected with the drive motor using a wiring (14). The wiring has a foam filled protective cladding and strands that are fixed in the cladding. The strands are arranged at a distance from each other. The protective cladding is formed from a thermosetting polyurethane-foam.