Hand-held Welding Tool Capacitor Module Inductance Discharge

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Solution Overview

Problem

Existing manual welding devices are hindered by the weight and length of supply lines, limiting flexibility and resulting in short discharge times due to the direct connection of power sources, which affects the welding process.

Innovation Solution

A hand-held welding device with a capacitor module and rechargeable Li-ion batteries, buffered by capacitors, and an adjustable inductance in the current path to manage high currents efficiently, along with a compact design and integrated sensors for optimal contact pressure control, allowing for adjustable inductance to extend discharge times and improve welding results.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If supply lines are used to connect power source to welding gun, then power can be delivered, but flexibility is reduced due to weight and length of lines

Engineering Contradiction:
ImproveflexibilityVSAvoidweight of supply lines
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The power delivery system is segmented into two parts: a compact power source unit with capacitor module that can be moved freely, and a stationary charging unit. This segmentation eliminates the need for long supply lines while maintaining power delivery capability, directly resolving the contradiction between flexibility and weight.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A capacitor module is introduced as an intermediary energy storage component between the power source and welding electrode. The capacitor stores energy locally and releases it during welding, eliminating the need for continuous power delivery through heavy supply lines, thus improving flexibility without sacrificing power delivery.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If capacitor module is directly connected to welding electrode, then high current can be delivered, but discharge time becomes too short

Engineering Contradiction:
Improvehigh current deliveryVSAvoiddischarge time
Core Design Contradiction:
PowerVSDuration of action of moving object

Solution Approach 1:

An inductor is introduced as an intermediary component in the current path between the capacitor module and welding electrode. The inductor's inherent property of opposing rapid changes in current flow naturally extends the discharge time constant of the RC circuit, allowing high current delivery to be maintained over a longer duration without sacrificing peak power capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Duration of action of moving object

If inductance is increased to extend discharge time, then welding process is improved, but device complexity increases

Engineering Contradiction:
Improvedischarge timeVSAvoiddevice complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The inductor required for extending discharge time is merged with the existing capacitor module housing, forming an integrated LC circuit assembly. This combination eliminates the need for separate inductor components and reduces overall device complexity while achieving the desired discharge time extension.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The inductor serves multiple functions: it extends discharge time, provides magnetic shielding, and can be integrated into the housing structure. This multi-functionality reduces the need for additional components, thereby minimizing device complexity while achieving the primary goal of extended discharge time.

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

The solution enables efficient, flexible, and optimized welding with adjustable discharge times between 0.2 ms to 5 ms, enhancing the welding process by managing current flow and contact pressure, thus improving the portability and effectiveness of the welding device.

Implementation Method 1

a capacitor module (21) within the housing (11), a first current path (23) that electrically connects the capacitor module (21) to the mount (16)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

an inductor is connected into the first current path. The additional inductance in the range of 0.5 to 5 microHenry according to the invention in the first current path lengthens the discharge time in the desired manner

Methodology Applied
Scientific EffectInductance: Inductor

Implementation Method 3

The accumulator module made of batteries, e.g. rechargeable Li-ion batteries, is buffered by capacitors. After welding, the capacitor module is recharged by the accumulator module.

Methodology Applied
Scientific EffectElectrochemical energy conversion: Battery (electricity)

Data Source

PatentEP2470323B1Hand-held welding tool comprising a housing, a receptacle, a capacitor module and interfac
Publication Date: 2014.09.24 HILTI AG
  • EP2470323B1 patent drawingFigure 1

AI summary

The invention relates to a hand-held welding tool (10) comprising a housing (11), a receptacle (16) for a welding stud or a welding electrode, a capacitor module (21) inside the housing (11), a first current path electrically connecting the capacitor module (21) to the receptacle, an electro-mechanical interface (15) on the housing (11) for fastening an accumulator module (13) to the housing (11) and a second current path electrically connecting the electro-mechanical interface (15) to the capacitor module (21).