Eddy Current Braking for Lock Security
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Solution Overview
Problem
Existing lock devices are vulnerable to unauthorized unlocking through bumping techniques, which require the same mechanical force as authorized unlocking, leading to high energy consumption and potential security breaches, especially in energy harvesting lock devices.
Innovation Solution
A bumping preventing arrangement that incorporates a transfer member with a magnet, electric conductors, and switches to induce eddy currents and create a magnetic force that acts as a brake against unauthorized movements, allowing for a lower authorized force hill and higher unauthorized force hill, thereby enhancing security and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring pushes the transfer member towards the locked position, then security against unauthorized bumping is improved, but the energy required for authorized unlocking increases substantially
Solution Approach 1:
The patent replaces the purely mechanical spring-based force hill with an electromagnetic system. A magnet on the transfer member interacts with electric conductors and switches to create a controllable magnetic force hill through eddy currents. This substitution allows the force hill to be activated only when needed for security, while authorized unlocking can occur with minimal energy by controlling the switch state.
2Reliability
If the same mechanical force hill is used for both authorized and unauthorized unlocking, then security is maintained, but energy consumption for authorized unlocking becomes excessively high
Solution Approach 1:
The patent makes the force hill dynamic by using controllable switches that can change the electrical circuit state. When the switches are closed, eddy currents are induced in the electric conductors as the magnet moves, creating a high magnetic force hill that resists unauthorized bumping. When the switches are open, no eddy currents are induced, allowing authorized unlocking with minimal energy. This dynamic control allows the system to adapt its resistance level based on the operation type.
3Reliability
If eddy currents are induced to create magnetic braking force against bumping, then resistance against unauthorized unlocking is improved, but the complexity of the electrical control system increases
Solution Approach 1:
The patent extracts the control function into separate, simple switches that can be integrated into the existing lock device control circuitry. The electric conductors are arranged as simple loops around the actuation axis, and the switches are positioned to be actuated by the transfer member's movement. This modular approach adds minimal complexity while achieving the desired magnetic braking effect against bumping.
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 solution effectively prevents unauthorized unlocking by increasing the force required for bumping while reducing the energy needed for authorized unlocking, thus providing high protection against bumping with low energy consumption.
Implementation Method 1
each switch being arranged to selectively close an electric circuit comprising the associated electric conductor such that eddy currents are induced in the electric conductors when the magnet moves along the actuation axis from the locked position towards the unlocked position
Implementation Method 2
eddy currents are induced in the electric conductors when the magnet moves along the actuation axis
Implementation Method 3
The eddy currents generate a magnetic force on the magnet acting against the movement of the magnet
Data Source
AI summary
A bumping preventing arrangement (10) for a lock device (38, 52, 68), the bumping preventing arrangement (10) comprising transfer member (12, 46, 64, 74) having a magnet (14), the transfer member (12, 46, 64, 74) being movable along an actuation axis (18) between a locked position (16) and an unlocked position (36); a plurality of electric conductors (20), each electric conductor (20) enclosing the actuation axis (18); and a plurality of switches (22), each switch (22) being associated with a respective electric conductor (20), and being arranged to selectively close an electric circuit comprising the associated electric conductor (20) such that eddy currents are induced in the electric conductors (20) when the magnet (14) moves along the actuation axis (18) from the locked position (16) towards the unlocked position (36). A lock device (38, 52, 68) and a method of controlling a lock device (38, 52, 68) are also provided.