Fastening Tool Home Position Sensing With Hall Effect Feedback
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Solution Overview
Problem
Mechanical switches in fastening tools, such as micro-limit switches, are unreliable due to mechanical robustness issues, leading to failed position detection mechanisms, overtravel, physical deformation, cycle fatigue, and electrical overload, resulting in inaccurate or faulty signals for the control module.
Innovation Solution
A fastening tool equipped with a Hall effect sensor system that uses a magnet attached to the drive shaft to detect changes in position, sending a signal to the controller for initiating the next drive cycle, providing a contactless and reliable home position sensing mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical switches (micro-limit switches) are used for home position detection, then the position detection mechanism can be implemented, but the reliability deteriorates due to mechanical robustness issues, overtravel, physical deformation, cycle fatigue, and electrical overload
Solution Approach 1:
The patent replaces mechanical switches with a Hall effect sensor system that uses a magnet attached to the drive shaft and a Hall effect sensor to detect the home position. This substitution eliminates mechanical contact, preventing wear, deformation, and electrical overload issues while maintaining position detection functionality. The magnet-sensor system provides contactless detection that is more reliable under cyclic operation.
Solution Approach 2:
The patent introduces a magnet as an intermediary element between the drive shaft and the detection system. The magnet attached to the drive shaft interacts with the Hall effect sensor to indicate position without requiring direct mechanical contact between the drive shaft and the sensor, thereby eliminating mechanical wear and improving reliability.
2Measurement precision
If mechanical switches are used for position detection, then the system can detect home position, but the measurement precision deteriorates due to faulty signals and inaccurate position detection
Solution Approach 1:
The Hall effect sensor system provides precise detection of the drive shaft's home position by detecting changes in magnetic field position. This contactless sensing method eliminates the signal faults and inaccuracies associated with mechanical switches, providing both high measurement precision and reliable signal transmission to the control module.
Solution Approach 2:
The Hall effect sensor continuously monitors the position of the magnet on the drive shaft and provides feedback signals to the control module. This feedback mechanism ensures accurate detection of the home position and enables the control module to initiate the next drive cycle at the correct moment, improving both measurement precision and signal reliability.
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
Ensures repeatable and accurate transmission of electrical signals to the control module when the drive shaft is in its home position, enhancing the tool's performance and reliability by eliminating mechanical switch failures.
Implementation Method 1
A sensor is configured to sense the characteristic of the sensor target and send a signal to the controller in response to the characteristic. the sensor is one of a Hall effect sensor and an omnipolar switch Hall effect sensor.
Data Source
AI summary
A fastening tool using Hall sensor technology as a contactless solution to home position sensing of a drive shaft. In this manner, an omnipolar switch Hall effect sensor PCB assembly can be placed in a fastening tool housing or on a driving mechanism of the tool to detect a magnet that is attached to a drive shaft. The drive shaft is attached to an eccentric member that can control the height or position of a compression piston. On the piston return cycle, the piston must stop within a predetermined range from bottom dead center in order to be in the home position. Through the connection with the eccentric member, the drive shaft carrying the magnet also returns to its home position. In the drive shaft home position, the magnet is within the Hall effect sensor sensing zone. As a result, the Hall effect sensor can detect the magnetic flux and send a corresponding signal to the controller.