Resistance Welding Pinch Point Safety Sensor
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Solution Overview
Problem
Resistance welding machines pose a risk of serious injury due to high force concentrations at pinch points, with existing safety systems relying on operator adjustments and being prone to mechanical errors, which can compromise safety if not properly set or maintained.
Innovation Solution
A passive sensing system that measures continuity between welding electrodes, preventing high force application unless continuity is detected, ensuring the electrodes clamp only on low-resistance materials and not on operators' fingers or body parts, and allowing for internal sensing independent of electrode position changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a limit switch with adjustable finger is used to detect electrode proximity, then the safety system can prevent high force application when electrodes are too close, but the system requires operator adjustment and is prone to mechanical errors that compromise safety
Solution Approach 1:
The patent replaces the mechanical limit switch system with an electrical continuity sensing system. Voltage is applied across the electrode gap and continuity is detected electrically rather than mechanically. This eliminates the need for operator-adjusted mechanical fingers and switches, providing more reliable and consistent detection of electrode proximity and material presence.
Solution Approach 2:
The continuity sensing system automatically detects electrode proximity and material presence without requiring operator intervention for adjustment or calibration. The system self-regulates by monitoring electrical continuity conditions, eliminating the need for operators to manually adjust mechanical components and reducing human error in safety detection.
2Reliability
If mechanical limit switches are used for safety detection, then the system can restrict force before electrode contact, but the mechanical components are subject to wear, misalignment, and operator adjustment errors
Solution Approach 1:
The patent eliminates mechanical limit switches, adjustment fingers, and associated mechanical components by implementing an electrical continuity sensing system. Voltage is applied across the electrode gap and continuity is detected through electrical measurement, removing all mechanical detection components that are subject to wear, misalignment, and adjustment errors.
Solution Approach 2:
The patent introduces an electrical field as an intermediary between the electrodes and the detection system. Instead of direct mechanical contact or proximity sensing, the electrical field mediates the detection process by allowing continuity measurement through the electrode gap, providing accurate detection without mechanical complexity.
3Productivity
If electrode force is applied before continuity detection, then the welding process can proceed efficiently, but high force can cause serious pinch-point injury to operators
Solution Approach 1:
The patent performs continuity detection before applying high electrode force. The system first applies voltage to detect continuity across the electrode gap, confirming proper electrode proximity and material presence. Only after successful continuity detection does the system proceed to apply high welding force, ensuring safety before the harmful action occurs.
Solution Approach 2:
The patent implements a feedback control system where continuity detection results directly control the application of electrode force. The sensing system continuously monitors electrical continuity conditions and provides feedback to the force application system, enabling or disabling high force based on detected conditions. This feedback mechanism prevents harmful force application when continuity conditions are not met.
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 system effectively prevents pinch-point injuries by ensuring high electrode force is only applied after continuity is detected, reducing the risk of injury and maintaining safety even if electrode spacing changes, without requiring operator adjustments.
Implementation Method 1
A passive sensing system that measures continuity between welding electrodes, preventing high force application unless continuity is detected
Data Source
AI summary
There is described a continuity sensing system that operates with a resistance-welding machine. This sensing system measures continuity between the welding electrodes after the welding machine has been initiated and prevents application of high electrode force between the electrodes if the continuity measured is below a reference level. The result is a fully passive system that prevents serious high electrode force that would cause serious pinch-point injury to the operator of the welder. The present invention also includes methods of controlling pneumatic systems on resistance-welding machines to apply low force between welding electrodes until continuity between the welding electrodes has been detected.