Bi-Stable Latching Solenoid Door Lock Power Management

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Solution Overview

Problem

Conventional electromagnetic door locks lose their holding force during power outages and consume significant power and generate heat when powered on, making them inefficient and unreliable for maintaining a secured state.

Innovation Solution

A bi-stable electromagnetic lock system with a solenoid component and holder components that use magnetic forces to hold the lock pin in desired positions without continuous power, including a sensor to detect power loss and automatically transition the lock pin to a secure position before power is lost, and an auxiliary power supply for maintaining the lock state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electromagnetic locks are used to maintain locked position, then the door can be secured, but significant power is consumed and heat is generated

Engineering Contradiction:
Improvedoor securityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The lock system uses periodic pulsed power application instead of continuous power supply. The controller applies power in short pulses to the solenoid coil only when needed to change lock state, then uses the bi-stable mechanism to maintain the state without continuous power, dramatically reducing energy consumption while maintaining security

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The bi-stable latching solenoid mechanism is designed to maintain its locked or unlocked state automatically without continuous external power input. Once the solenoid plunger is moved to a desired position by a power pulse, the magnetic latching mechanism self-maintains that position, making the system self-sustaining and eliminating the need for continuous power consumption

Inventive Principle:
Principle #25Self-service

2Reliability

If conventional electromagnetic locks are used to maintain locked position, then the door can be secured, but heat is generated during operation

Engineering Contradiction:
Improvedoor securityVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

By using periodic pulsed power instead of continuous power supply, the solenoid coil is energized only briefly to change state, then remains de-energized while maintaining the lock position. This dramatically reduces the duration of heat generation while preserving the security function

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The bi-stable mechanism maintains the locked position through its inherent magnetic latching properties without requiring continuous power, thereby eliminating continuous heat generation from the solenoid coil while maintaining door security

Inventive Principle:
Principle #25Self-service

3Ease of operation

If conventional electromagnetic locks are used, then the lock can be controlled when powered, but the lock loses holding force during power outages

Engineering Contradiction:
Improvelock controlVSAvoidholding force during power loss
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The sensor detects power loss conditions in advance and triggers the controller to apply a power pulse to the solenoid, moving the plunger to the predetermined safe locked position before complete power failure occurs. This preliminary action ensures the lock maintains its holding force and secured state even during power outages

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses a small auxiliary power supply (such as a battery or capacitor) that provides brief power pulses only when needed for state changes or power loss recovery, rather than requiring continuous expensive main power. This short-living power source is depleted and recharged or replaced as needed, maintaining reliability during power outages

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Use of energy by moving object

If bi-stable latching solenoid is used to reduce power consumption, then energy efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidlock mechanism complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the solenoid actuator and the latching mechanism into a single integrated bi-stable latching solenoid assembly. The solenoid plunger directly interacts with the latching elements, merging the actuation and latching functions into one compact unit, which reduces overall device complexity despite the advanced functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bi-stable latching solenoid mechanism serves multiple functions: it acts as both the actuator and the latching mechanism, provides normal operation mode and power-loss safe mode, and can be controlled by various input methods. This multi-functionality reduces the need for separate components, thereby managing complexity while achieving energy efficiency

Inventive Principle:
Principle #6Universality (Multi-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

The system maintains the door lock in a secure state during power outages and reduces power consumption and heat generation, ensuring efficient and reliable operation across various power conditions.

Implementation Method 1

The solenoid component can comprise at least a first holder component and a second holder component, wherein the first holder component can apply a desired amount of force (e.g., magnetic force) on the solenoid plunger

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 2

The lock component can comprise a sensor component that can sense when power to the lock component is about to be lost

Methodology Applied
Scientific EffectPower detection:

Data Source

PatentEP2390444B1Efficient and safe door locking control in power-off and power-on conditions
Publication Date: 2019.10.23 ROCKWELL AUTOMATION TECH INC
  • EP2390444B1 patent drawingFigure 1
  • EP2390444B1 patent drawingFigure 2
  • EP2390444B1 patent drawingFigure 3

AI summary

Systems, methods, and devices that efficiently control the operating state of an electromagnetic lock under power on and power off conditions are presented. A lock component includes a solenoid component (e.g., bi-stable latching solenoid) that holds a lock pin in a locked or unlocked position without using power to hold the lock pin in the desired position, and using power to transition from one position to another position. A sensor component senses when power to the lock component will be lost, and if the lock pin is not in the desired position for the power off condition, the lock pin can be transitioned to the desired position, and if the lock pin is in the desired position for power off condition, the lock component can maintain the lock pin in the desired position, while the lock component is in the power off condition.