Electropermanent Magnet Actuator for Low-Power Lock Holding
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Solution Overview
Problem
Existing actuators for lock devices face challenges in achieving low power consumption, small size, reliable operation, simple design, protection against tampering, and high magnetic holding force relative to size.
Innovation Solution
An actuator utilizing a soft magnet and a permanent magnet combination, where a current pulse flips the soft magnet's polarity, generating a magnetic field to move a movable member between positions, with the permanent magnet maintaining the position without power, and optionally using elastic elements for movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a motor or solenoid is used as a powered actuator, then the actuator can lock and unlock the lock device, but the power consumption is high and the device size is large
Solution Approach 1:
The patent replaces traditional motor or solenoid actuators with an electropermanent magnet system that uses electrical fields to magnetize/demagnetize permanent magnets, thereby substituting a high-power mechanical actuation system with a low-power magnetic field-based system. The electropermanent magnet generates magnetic fields to move the movable member without requiring continuous power supply, achieving both low power consumption and reliable locking.
Solution Approach 2:
The patent changes the magnetic state (magnetized/demagnetized) of the permanent magnet by applying electrical pulses to the electropermanent magnet. By switching the magnetic parameter of the permanent magnet between two states, the system achieves bistable operation with minimal energy consumption, resolving the contradiction between low power usage and reliable locking/unlocking functionality.
2Ease of operation
If a spring is added to return the plunger to original position, then the actuator can reset without power, but the device complexity increases
Solution Approach 1:
The patent employs elastic elements (springs) that automatically return the movable member to its initial position when the magnetic holding force is released. The elastic element stores mechanical energy during actuation and releases it to reset the system, enabling automatic reset without additional power supply or complex control mechanisms.
3Volume of moving object
If the actuator size is reduced, then the device is more compact, but the magnetic holding force decreases
Solution Approach 1:
The patent uses a composite magnetic system combining electropermanent magnet material with permanent magnet material. This composite approach allows the generation of strong magnetic fields in a compact configuration, as the electropermanent magnet can be magnetized to high flux density states, providing sufficient holding force in a reduced volume compared to traditional electromagnetic actuators.
4Power
If a coil is used to generate magnetic flux, then the actuator can move the shaft, but the power consumption increases
Solution Approach 1:
The patent uses periodic electrical pulses applied to the coil of the electropermanent magnet to switch the magnetic state of the permanent magnet between magnetized and demagnetized conditions. Instead of continuous power supply, brief periodic pulses are sufficient to change the magnetic state, and the system maintains its state without power, dramatically reducing energy consumption while retaining full actuation capability.
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 actuator achieves low power consumption, small size, reliable operation, and high magnetic holding force, while providing protection against tampering, and can be used in lock devices and handle devices for doors and windows.
Implementation Method 1
The coil is energized by connection to a source of electrical current and thereby generates magnetic flux
Implementation Method 2
the permanent magnet and the soft magnet combine to generate a magnetic field acting on the magnetic target section
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
Actuator (10) comprising a base section (14,14a,14b); a permanent magnet (18,18a,18b); an electro permanent magnet (20, 20a, 20b); a coil (22, 22a, 22b) located around the electro permanent magnet (20, 20a, 20b); a power controller (24, 24a, 24b); and a movable member (28) comprising at least one magnetic target section (36), the movable member (28) being arranged to move to a first position (12) relative to the base section (14,14a,14b), when the electro permanent magnet (20, 20a, 20b) adopts a first polarity, and arranged to move to a second position (46) relative to the base section (14,14a,14b) due to a magnetic field generated by the permanent magnet (18,18a,18b) and the electro permanent magnet (20, 20a, 20b) in combination and acting on the magnetic target section (36), when the electro permanent magnet (20, 20a, 20b) adopts a second polarity. A lock device (50), a handle device (86) and a method are also provided.