Triangular Reed Sensor With Opposing Magnet Shielding
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Solution Overview
Problem
Existing position sensors are not effectively activated by a magnetic exciter part while being protected from external magnetic fields, requiring a simple and reliable design.
Innovation Solution
A position sensor with three reed contacts arranged in a triangular configuration, where the first two contacts are activated by a pair of bar magnets with aligned poles, and the third contact is designed to remain inactive due to an oppositely polarized magnet, ensuring that external magnetic fields activate all contacts, generating an error signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a position sensor is designed to be activated by a magnetic exciter part, then it can detect position changes, but it becomes vulnerable to activation by external magnetic fields
Solution Approach 1:
The patent applies local quality by creating different magnetic field characteristics at different locations. The exciter part generates a specific magnetic field pattern that is locally unique to its position relative to the reed contacts. External magnetic fields cannot replicate this specific local field distribution, allowing the sensor to distinguish between intentional activation by the exciter part and interference from external sources.
Solution Approach 2:
The patent employs asymmetry in the magnetic field configuration. The exciter part creates an asymmetric magnetic field pattern relative to the triangular arrangement of reed contacts. This asymmetric pattern is characteristic of the exciter part's position and cannot be replicated by external magnetic fields, enabling reliable discrimination between valid sensor activation and external interference.
2Reliability
If three reed contacts are arranged in a triangular configuration with corresponding magnets, then the sensor can be activated by the exciter part, but external magnetic fields may also activate the contacts
Solution Approach 1:
The patent implements feedback through the evaluation unit that monitors the activation pattern of the three reed contacts. When all three contacts are activated simultaneously, the evaluation unit generates an error signal indicating external magnetic field interference. This feedback mechanism allows the system to detect and respond to invalid activation patterns, maintaining information integrity by distinguishing between valid exciter part activation and external interference.
3Object-affected harmful factors
If the third magnet is positioned to protect the third reed contact, then external field activation is prevented, but the magnetic field influence from the first two magnets is reduced
Solution Approach 1:
The patent applies the counterweight principle by positioning the third magnet with opposite polarity between the first two magnets and the third reed contact. This third magnet acts as a magnetic shield, counteracting the magnetic field lines from the first two magnets that would otherwise reach the third reed contact. The third magnet absorbs or redirects these field lines, preventing external magnetic fields from activating the third contact while maintaining the overall sensor functionality.
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 configuration allows the sensor to be activated only by the intended magnetic exciter part, preventing activation by external fields and providing a tamper-proof proximity sensing mechanism.
Implementation Method 1
The exciter part (13) has three bar magnets (17, 18, 19) arranged in a corresponding triangular arrangement
Implementation Method 2
two first magnets (17, 18) have the same polarity and are arranged at a first distance from one another. The third magnet (19) is poled in the opposite direction to the first two
Implementation Method 3
The position sensor (11) has three reed contacts (27, 28, 29) aligned parallel to one another in a triangular arrangement next to one another
Data Source
Figure 1~5
Figure 6a~6d
AI summary
The set has a position sensor (11) with three parallel reed contacts (27,28,29), aligned next to each other, in a triangular arrangement, and an exciter part (13). The exciter part has three permanent magnets (17,18,19) arranged in a triangular arrangement corresponding the reed contacts. The pole-axes are aligned parallel to each other, from which two magnets are evenly arranged at a distance, to be aligned in an activating position with two reed contacts, and by which the third magnet (19) is polarized in the direction opposite to the two magnets.