Self-adjusting Welding Torch Liner Assembly

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Solution Overview

Problem

Conventional welding torch liners often become unseated due to expansion, leading to improper electrode wire feeding and increased wear of the contact tip, resulting in premature replacement.

Innovation Solution

A self-adjusting liner assembly with a spring-loaded mechanism that constantly pushes the liner forward into a retaining head, ensuring proper wire feeding and reducing contact tip wear, while allowing passage of welding gas through the assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the liner is secured to the retainer in a conventional welding torch, then the liner can be installed and electrode wire can be fed through, but the liner becomes unseated due to expansion of the welding torch

Engineering Contradiction:
Improveliner position stabilityVSAvoidwire feeding reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The liner assembly incorporates a movable piston that can slide within the retainer, allowing the system to dynamically adjust to thermal expansion. The piston moves forward when the torch expands, maintaining continuous contact between the liner and retainer, thereby preventing liner disengagement and ensuring reliable wire feeding throughout operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring mechanism changes the positional parameter of the piston dynamically. As the torch heats up and expands, the spring compresses, allowing the piston to move forward and maintain proper liner positioning. This parameter change compensates for dimensional changes in the torch body due to thermal expansion.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the liner becomes unseated from the retainer, then the welding torch structure remains simple, but improper feeding of electrode wire into contact tip occurs

Engineering Contradiction:
Improveliner assembly complexityVSAvoidwire feeding quality
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The spring-loaded piston mechanism is self-actuating and requires no external control. It automatically responds to thermal expansion by moving forward, maintaining liner positioning without requiring operator intervention or complex control systems, thus achieving reliable wire feeding with minimal added complexity.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the liner becomes unseated, then the assembly structure remains simple, but increased wear of contact tip occurs leading to premature replacement

Engineering Contradiction:
Improveassembly structure complexityVSAvoidcontact tip service life
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

The spring mechanism performs preliminary action by continuously pushing the piston and liner forward into proper engagement with the retainer before any disengagement can occur. This preventive action ensures the liner remains seated throughout thermal cycles, preventing premature contact tip wear and extending component service life.

Inventive Principle:
Principle #10Preliminary action

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 self-adjusting liner assembly maintains proper liner position, ensures consistent electrode wire feeding, and reduces contact tip wear by utilizing a resilient member to urge the piston forward, maintaining efficient operation even as the torch expands or the liner is consumed.

Implementation Method 1

Another spring is disposed in the main body aperture and envelops a portion of the retainer and the piston. The resilient member engages the piston shoulder and the retainer shoulder, and urges the piston toward the forward end of the main body.

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2117759B1Self-adjusting liner assembly for welding torch
Publication Date: 2016.08.17 ILLINOIS TOOL WORKS INC
  • EP2117759B1 patent drawingFigure 1
  • EP2117759B1 patent drawingFigure 2
  • EP2117759B1 patent drawingFigure 3

AI summary

A self-adjusting liner assembly for a welding torch includes an elongated tubular main body having forward and rearward ends. An elongated tubular retainer including a shoulder is mountable in the main body. An elongated tubular piston including a shoulder cooperates with the retainer in a telescoping relationship in the main body. A resilient member is disposed in the main body and envelops a portion of the retainer and the piston. The resilient member urges the shoulders away from each other and the tubular piston toward the forward end of the main body.