Touch-Retract TIG Torch With Fixed Electrode Retraction
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Solution Overview
Problem
Existing touch retract TIG welding systems face challenges in accurately locating the electrode due to concealment by the contact tube and require complex and expensive positional servo systems to maintain consistent weld quality as the electrode wears, leading to increased arc gap and varying weld characteristics.
Innovation Solution
A mechanical retraction mechanism in the TIG welding torch featuring a piston with gripper arms that pivot to engage and clamp the electrode, a swing arm for activating the retraction, and a return spring to maintain consistent electrode retraction distance, utilizing a solenoid or actuator for controlled retraction and engagement, ensuring consistent weld quality despite electrode wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a touch retract system is used to overcome electrical disadvantages of high voltage arc start, then the electrode can be retracted to prevent arcing to current return nozzle, but the electrode becomes difficult to locate on the weld site due to concealment by contact tube
Solution Approach 1:
The electrode is pre-positioned to protrude from the contact tube before welding begins, allowing the operator to visually locate and position it on the weld site. The retract mechanism is activated only after proper positioning is achieved, maintaining the electrode in a visible state during setup while preventing arcing during operation.
2Power
If the electrode is retracted in touch retract systems, then a high current arc is drawn between electrode tip and workpiece, but the gap created increases as the electrode wears leading to changed weld characteristics
Solution Approach 1:
A feedback mechanism continuously monitors the electrode length and automatically adjusts the retraction distance to maintain a constant arc gap. As the electrode wears and shortens, the system compensates by retracting less, ensuring consistent weld characteristics throughout the electrode's service life.
Solution Approach 2:
The retraction mechanism transitions from a fixed static position to a dynamic adjustable position. The system adapts the retraction distance in real-time based on electrode wear, allowing the electrode to maintain optimal positioning despite changes in length, thereby preserving weld quality consistency.
3Manufacturing precision
If complex positional servo systems are used to maintain consistent electrode position, then weld quality can be maintained despite electrode wear, but the system becomes expensive and complex
Solution Approach 1:
The invention replaces expensive, complex servo systems with a simpler, more economical mechanism. While the electrode itself is a consumable that requires replacement, the positioning system uses affordable components that maintain precision without the complexity and cost of industrial servo mechanisms.
Solution Approach 2:
The system uses the electrode's own physical characteristics and wear pattern as feedback, eliminating the need for external sensors and complex control systems. The mechanism self-adjusts based on the electrode's position and wear, providing consistent weld quality through a simple, inherent feedback loop rather than expensive electronic control.
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 provides a simple, cost-effective method to maintain consistent weld quality by ensuring a fixed retraction distance of the electrode, independent of wear, resulting in reliable and precise welds without the need for complex positional servo systems.
Implementation Method 1
The welding torch may further comprise a solenoid arranged to activate and deactivate the retract mechanism
Implementation Method 2
The activating means may be a solenoid, a linear motion actuator, a pneumatic or hydraulic cylinder actuator
Implementation Method 3
The welding torch may further comprise a return spring arranged to return the swing arm to the unengaged position
Implementation Method 4
the piston lock remains stationery as the gripper arms pivot and retract the piston together with the gripper arms, thus increasing the frictional force between the gripper arms and the electrode
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
This invention relates to an apparatus for use in welding, in particular in Tungsten Inert Gas (TIG) welding. The invention provides a touch retract welding torch (10) comprising: an electrode (27); a nozzle (28) surrounding the electrode (27); a mechanical retraction mechanism (21) comprising a gripper (13) for clamping the electrode and arranged in operation to engage the gripper and retract the electrode (27) away from a weld site by a predetermined distance; activating means (24) arranged in operation to trigger said retraction mechanism while providing the basis by which an arc maybe drawn from an initial contact point and maintained consistently over a significant number of operational cycles.