Magnet in Bolt for Tamper-Resistant Lock Detection

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Solution Overview

Problem

Existing electronic lock systems can be tampered with by inserting a loose locking bolt or material into the striking plate aperture, leading to false interpretations of the lock's secured state.

Innovation Solution

A lock assembly that includes a striking plate with a magnetometer and a bolt with a magnet, where the magnetometer is powered only when an object is detected, and the lock considers the bolt secured only when a valid magnetic field is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sensor continuously monitors the bolt position, then the lock status can be detected, but the system becomes vulnerable to tampering with loose bolts or materials

Engineering Contradiction:

Improvelock status detection accuracyVSAvoidtampering risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical sensor detection system with a magnetic field-based detection system. A magnetometer detects the magnetic field signature of the bolt, and a magnet embedded in the bolt creates a unique magnetic signature that cannot be replicated by loose materials. This substitution of mechanical detection with magnetic field detection eliminates tampering vulnerabilities while maintaining reliable lock status monitoring.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnet as an intermediary element embedded in the bolt, which mediates the interaction between the bolt and the magnetometer. This magnet creates a distinctive magnetic field that serves as a verification mechanism, allowing the system to distinguish between a genuine bolt and tampering materials without direct mechanical contact or exposure of the sensor.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a magnetometer is continuously powered to detect magnetic fields, then tampering can be detected, but energy consumption increases

Engineering Contradiction:

Improvetampering detection capabilityVSAvoidmagnetometer power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by powering the magnetometer only during specific events: when an object is detected by the sensor device or when the lock status needs verification. The magnetometer is not continuously powered but operates periodically based on system needs, significantly reducing energy consumption while maintaining tampering detection capability when required.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the magnetometer's operational state variable rather than static. The magnetometer dynamically transitions between powered and unpowered states based on system conditions, allowing the system to adapt power consumption to actual operational requirements while maintaining security functionality when needed.

Inventive Principle:

Principle #15Dynamics

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 significantly reduces the risk of attackers tampering with the lock system, ensuring that the lock is only considered secured when a valid bolt is present, thus maintaining the integrity of the locking mechanism.

Implementation Method 1

a magnetometer arranged in proximity of the aperture; and a sensor device for detecting proximate presence of an object, wherein the sensor device is configured to power up the magnetometer when the sensor device detects proximate presence of an object; wherein the lock assembly is configured to detect, using the magnetometer and magnet when the bolt is in a protruded position through the aperture

Methodology Applied

Scientific EffectMagnetic field detection: Magnetism

Data Source

PatentUS12297661B2Magnet in bolt

Publication Date: 2025.05.13 ASSA ABLOY AB

AI summary

It is provided a lock assembly comprising: a striking plate assembly comprising an aperture and a magnetometer arranged in proximity of the aperture; a bolt being displaceable to enable movement through the aperture of the striking plate assembly, the bolt comprising a magnet; and a sensor device for detecting proximate presence of an object, wherein the sensor device is configured to power up the magnetometer when the sensor device detects proximate presence of an object; wherein the lock assembly is configured to detect, using the magnetometer and magnet when the bolt is in a protruded position through the aperture.