Welder Electrode Indirect Fastener Position Sensing
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Solution Overview
Problem
Existing weld gun systems face challenges in accurately detecting the proper orientation of fasteners during resistance welding, leading to inefficiencies and potential damage due to improper loading or orientation.
Innovation Solution
The introduction of a position sensor with a linear variable displacement transducer (LVDT) and a movable pin system within the electrode assembly, which allows for precise detection of fastener orientation by tracking the pin's position through multiple axial movements, enabling better control over the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear variable displacement transducer (LVDT) is connected to an electrode arm to measure arm movement for detecting fastener presence and orientation, then fastener presence can be detected, but accurate detection of proper fastener orientation becomes difficult
Solution Approach 1:
The electrode arm is segmented into multiple measurement points: the main electrode arm movement is measured by the LVDT, and additional pins are positioned at different locations (including inside the electrode bore) to independently measure orientation. Each pin provides segmented measurement data that, when combined, enables accurate determination of both presence and orientation of the fastener.
Solution Approach 2:
Multiple pins are introduced as intermediary elements between the electrode arm and the measurement system. These pins make contact with specific features of the fastener (such as the head or projections) and transmit positional information to the LVDT, enabling indirect but precise measurement of fastener orientation without directly measuring the fastener itself.
2Loss of information
If the electrode arm moves a greater amount to detect no fastener presence, then presence detection is achieved, but the system cannot distinguish between absent fastener and improperly oriented fastener
Solution Approach 1:
The detection system transitions from one-dimensional measurement (single arm displacement) to multi-dimensional measurement by positioning pins at different locations and orientations within the electrode assembly. This creates multiple measurement dimensions that allow the system to distinguish between different fastener states (absent, present but misoriented, properly oriented) by analyzing the pattern of displacements across all pins.
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 provides accurate detection of fastener orientation, preventing welding errors and ensuring proper fastener engagement, thereby enhancing the control and reliability of the welding operation.
Implementation Method 1
The position sensor has a linear variable displacement transducer (LVDT).
Data Source
AI summary
An upper electrode assembly for welding fasteners includes a body that supports an electrode that has an aperture. The aperture is configured to receive a movable pin of a lower electrode assembly arranged opposite the upper electrode assembly. The lower electrode assembly supports a fastener in a welding position. The upper electrode assembly includes a position sensor which includes a position sensor member that is arranged in the body and is configured to cooperate with the pin to detect a fastener welding characteristic.