Plasma Torch Head Secured by Trapezoidal Thread Ring

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Solution Overview

Problem

The existing plasma torches with removable heads face issues due to thread deterioration from abrasion during frequent assembly and disassembly, leading to difficulties in mounting and sealing, especially when materials like stainless steel and copper or brass are used, resulting in improper contact and sealing between the torch head and body.

Innovation Solution

The use of isosceles trapezoidal threads on both the torch head and body, made of different materials such as stainless steel and brass, with a nickel-coated brass ring, minimizes abrasion and seizing, ensuring secure and precise mounting while maintaining a good seal and contact, and features a robust design resistant to corrosion and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a threaded ring is used to secure the torch head to the base, then the torch head can be mounted and dismounted, but the thread deteriorates due to abrasion during intensive use

Engineering Contradiction:
Improvemounting and dismounting operationVSAvoidthread integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention applies composite materials by combining stainless steel (for the base thread) with copper or brass (for the ring thread). This material combination reduces abrasion and seizing during repeated mounting and dismounting operations, thereby preserving thread integrity while maintaining ease of operation.

Inventive Principle:
Principle #40Composite materials

2Strength

If the base is made of stainless steel and the clamping ring is made of copper or brass, then the ring provides good clamping, but seizing occurs between the different materials

Engineering Contradiction:
Improveclamping strengthVSAvoidscrewing and unscrewing operation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The invention deliberately uses composite materials (stainless steel base with copper or brass ring) to achieve good clamping strength. The material combination reduces seizing during screwing and unscrewing operations compared to using the same material for both components, thus maintaining ease of operation while preserving clamping strength.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the thread is tightened to ensure proper seal and contact, then sealing is improved, but the thread deteriorates faster due to increased friction

Engineering Contradiction:
Improvesealing qualityVSAvoidthread service life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention uses composite materials (stainless steel base thread with copper or brass ring thread) to reduce friction and abrasion during tightening operations. This allows the thread to be tightened sufficiently for proper sealing while minimizing thread deterioration, thereby extending thread service life while maintaining sealing quality.

Inventive Principle:
Principle #40Composite materials

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 allows for easy and precise manual or automatic assembly and disassembly of the torch head, maintaining a secure seal and contact, reducing thread wear and ensuring reliable operation in corrosive and dusty environments.

Implementation Method 1

The ring is made of brass with an external nickel coating

Methodology Applied
Scientific EffectCoatings: Coatings

Data Source

PatentEP2292366B1Plasma torch with a removable head secured by means of a ring having a trapezoidal thread
Publication Date: 2020.06.03 LINCOLN GLOBAL INC
  • EP2292366B1 patent drawingFigure 1
  • EP2292366B1 patent drawingFigure 2

AI summary

The plasma cutting torch head comprises an upstream end and a downstream end, and a fixing ring (3) horizontally rotating at the upstream end of the head. The ring comprises a thread fixed on its inner wall to secure the torch head with torch body (2), where a screw thread of the threading (5) is a symmetrical trapezoidal section. The threading comprises 3-6 threads per 2.54 cm. Two sides (7) of each thread of the trapezoidal section form an angle of 29[deg] . The distance between the surface of the thread forming a small base of the trapezoid and the axis (4) of the torch head is 60.2 mm. The plasma cutting torch head comprises an upstream end and a downstream end, and a fixing ring (3) horizontally rotating at the upstream end of the head. The ring comprises a thread fixed on its inner wall to secure the torch head with torch body (2), where a screw thread of the threading (5) is a symmetrical trapezoidal section. The threading comprises 3-6 threads per 2.54 cm. Two sides (7) of each thread of the trapezoidal section form an angle of 29[deg] . The distance between the surface of the thread forming a small base of the trapezoid and the axis (4) of the torch head is 60.2 mm. The thread is placed in the inner wall of the ring made of copper or brass partially covered with a nickel coating. Independent claims are included for: (1) an assembly formed of a plasma cutting torch head; and (2) a process for plasma arc cutting.