Steering Wheel Foam Conductor Insertion Tool

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Solution Overview

Problem

Existing methods for introducing electrical conductors, such as heating wires, into the foam covering of a steering wheel skeleton are time-consuming and labor-intensive, requiring additional steps for insertion and securing the wires, which affects the uniformity and efficiency of heating.

Innovation Solution

A method and tool combination that simultaneously cuts into the foam and inserts the electrical conductor, using a cutting tool with an integrated insertion tool, allowing for a single work step and secure fixation through elastic closure of the cut edges or thermoplastic adhesive activation, ensuring quick and even placement of the conductor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electrical conductor is inserted using previously known methods, then the conductor can be reliably held in the foam, but the introduction process is very time-consuming and labor-intensive

Engineering Contradiction:
Improveconductor holding reliabilityVSAvoidconductor introduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines the cutting operation and conductor insertion operation into a single integrated tool and process step. The cutting tool creates an incision in the foam while simultaneously guiding the conductor into the incision, eliminating the need for separate insertion and securing steps. This merging of operations directly resolves the contradiction by maintaining reliable conductor holding through the foam's elastic closure while dramatically improving introduction efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cutting tool creates the incision and begins the insertion process simultaneously, preparing the path for conductor placement before the conductor fully enters the foam. The cut edges are elastically pushed apart in advance by the cutting action, creating an open pathway that guides the conductor into position before the edges return to close and secure it.

Inventive Principle:
Principle #10Preliminary action

2Power

If the heating wires are arranged at the smallest possible depth in the foam covering, then good and efficient heat output is achieved, but the wires must be reliably held to prevent slipping

Engineering Contradiction:
Improveheat output efficiencyVSAvoidwire position stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The foam material's elastic properties enable it to self-close the incision after the conductor is inserted, automatically securing the conductor in place without requiring additional fastening mechanisms. The foam's natural elasticity provides the holding force that prevents wire slipping while allowing the wire to be positioned at the optimal shallow depth for heat output efficiency.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If the heating wires are arranged at a constant depth in the foam covering, then uniform heating is ensured, but the introduction process becomes more complex

Engineering Contradiction:
Improveconductor depth uniformityVSAvoidintroduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cutting tool is designed to perform multiple functions simultaneously: cutting the foam, guiding the conductor, and controlling the insertion depth. This multi-functional tool design achieves constant conductor depth (ensuring uniform heating) without significantly increasing process complexity, as the same tool that creates the incision also controls the conductor placement depth through its structural design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach significantly reduces the time and effort required for conductor placement, ensures secure and uniform heating, and allows for precise control of the conductor's depth and orientation, enhancing the efficiency and reliability of the heating process.

Implementation Method 1

the cut edges, which have been pressed apart, rest against one another again. The edges of the cut are elastically pushed apart when the incision is made by the cutting tool and, after the cutting tool is advanced or removed, they return elastically to their starting position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the conductor/wire has a thin thermoplastic adhesive coating. This can be activated by energizing / heating, which additionally fixes the wire

Methodology Applied
Scientific EffectThermoplastic adhesive activation: Adhesive

Implementation Method 3

the conductor is bonded to the encapsulation in another way, for example by a Smartbond process. According to a further preferred embodiment it is provided that the conductor is fixed in the encapsulation by brief heating and subsequent cooling. In this method, the heating is preferably carried out to a temperature in the range of the melting temperature of the surrounding foam

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3057745B1Method, tool, and tool assembly for introducing an electrical conductor into a foam cladding of a steering wheel frame, and vehicle steering wheel
Publication Date: 2020.12.23 ZF AUTOMOTIVE SAFETY GERMANY GMBH
  • EP3057745B1 patent drawingFigure 1
  • EP3057745B1 patent drawingFigure 2a~2b
  • EP3057745B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a method for introducing an electrical conductor (22), in particular a heating wire, into a foam cladding (20) of a steering wheel frame (18), comprising the following steps: making at least one cut (26) into the foam cladding (20) by means of a cutting tool (34), and simultaneously introducing the conductor into the produced cut (26). The invention further relates to a tool and a tool assembly for performing said method and to a vehicle steering wheel.