Bistable Magnetic Locking Device with Rotating Permanent Magnet

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Solution Overview

Problem

Existing locking devices fail to provide two stable end-positions, a locking and a released position, without the application of holding voltage, and often have complex constructions that lead to inefficient operation and high energy consumption.

Innovation Solution

An electromechanically actuated, bistable magnetic locking device is designed with a permanent magnet mounted on a rotating crank-shaft, where the magnetic forces between the electromagnetic solenoid and the permanent magnet allow for two stable positions without holding voltage, utilizing repulsive and attraction forces to switch between locking and released states efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electromagnetic solenoid with steel spring is used, then locking action is achieved, but two stable end-positions without holding voltage are not provided

Engineering Contradiction:
Improvestable end-positionsVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the conventional steel spring mechanical system with a permanent magnet-based magnetic field system. The permanent magnet interacts with the electromagnetic solenoid to provide two stable end-positions (locking and released) without requiring holding voltage, thereby achieving bistability through magnetic field interaction rather than mechanical spring force.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention combines electromagnetic solenoid with permanent magnet in a composite structure. The electromagnetic solenoid generates a magnetic field that interacts with the permanent magnet's field, creating two stable equilibrium positions. This composite system integrates both electromagnetic and permanent magnetic properties to achieve the desired bistable behavior.

Inventive Principle:
Principle #40Composite materials

2Reliability

If electromagnetic solenoid and permanent magnet are used for locking, then locking action is achieved, but two stable end-positions without holding voltage are not provided

Engineering Contradiction:
Improvestable end-positionsVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The permanent magnet serves itself by maintaining a persistent magnetic field without requiring external energy input. The interaction between the permanent magnet's field and the electromagnetic solenoid's field creates two stable end-positions that are maintained passively without holding voltage, making the system energy-efficient for maintaining locked or released states.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses periodic pulsing of the electromagnetic solenoid to switch between the two stable states. Instead of continuous holding voltage, brief pulsing actions are sufficient to transition the permanent magnet between its two stable positions, reducing overall energy consumption while maintaining reliable state changes.

Inventive Principle:
Principle #19Periodic action

3Reliability

If electromotor and spindle drive gear are used, then two stable end-positions are provided, but construction becomes complicated and space demand increases

Engineering Contradiction:
Improvestable end-positionsVSAvoidmechanical construction
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent eliminates the electromotor and spindle drive gear mechanical transmission system by directly using the interaction between electromagnetic solenoid and permanent magnet to achieve the two stable end-positions. This substitution removes complex mechanical components, reduces space requirements, and simplifies the overall device construction while maintaining reliable bistable operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If permanent magnet turns away 90 degrees with complicated mechanical interconnection, then locking position is achieved, but magnetic force acts with loss and energy consumption increases

Engineering Contradiction:
Improvelocking positionVSAvoidenergy loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Instead of having the permanent magnet rotate 90 degrees with complicated mechanical interconnection, the invention inverts the approach by having the electromagnetic solenoid's magnetic field directly interact with the permanent magnet in a linear arrangement. This inversion eliminates the need for 90-degree rotation and complex mechanical linkages, allowing the magnetic force to act directly without loss and reducing energy consumption while achieving reliable locking position.

Inventive Principle:
Principle #13The other way round (Inversion)

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 device achieves two stable end-positions without holding voltage, ensuring simple, efficient, and reliable operation, replacing complex locking devices with reduced energy consumption and easier industrial application.

Implementation Method 1

an electromagnet (13) having a magnetic core (14), wherein under a voltage-free condition there is a magnetic attraction force between the magnetic core (14) of the electromagnetic solenoid (13) and the permanent magnet (12)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a permanent magnet (12) accommodated in a magnet casing (20) mounted to the crank-shaft (15)

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP3119966B1Bistable electromechanical magnetic locking device
Publication Date: 2019.10.09 SUMEGI ISTVAN ANDOR
  • EP3119966B1 patent drawingFigure 1
  • EP3119966B1 patent drawingFigure 2
  • EP3119966B1 patent drawingFigure 3

AI summary

An electromagnetically actuated, bistable locking device is disclosed. The locking device comprises a lock pin (11) that is moveable substantially along a longitudinal axis between an extended position and a retracted position; at least one permanent magnet (12) with two pole ends, said at least one permanent magnet mounted for rotation between a first magnetic orientation associated with an extended position of the lock pin (11) and a second magnetic orientation associated with a retracted position of the lock pin (11); at least one electromagnet (13) having first and second ends and electromagnetically actuated in one of said extended and retracted positions of the lock pin (11) to provide a first orientation of magnetic field, and in the other of said extended and retracted positions of the lock pin (11) to provide a second orientation of magnetic field, said second orientation of magnetic field being substantially the reverse of the first orientation of the magnetic field; a mechanical interconnection between the pin lock (11) and the at least one permanent magnet (12) for moving said pin lock (11) between the extended and the retracted positions of the lock pin (11) at the actuation of the electromagnet (13); wherein each of the at least one permanent magnet (12) is arranged adjacent to the first end of the respective one of the at least one electromagnet (13). The mechanical interconnection comprises a rotatable crank-shaft (15) extending perpendicularly to said longitudinal axis of the lock pin (11), and to which the at least one permanent magnet (12) is rigidly mounted, said crank-shaft (15) having at least one eccentric section to which the lock pin (11) is pivotably coupled; and guiding means for guiding the lock pin (11) substantially along said longitudinal axis.