Bi-stable Solenoid Elevator Door Lock for Power Outage Safety
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Solution Overview
Problem
Existing elevator door locking systems are prone to malfunction during power outages and require frequent maintenance due to wear and tear, especially in dirty environments, and struggle to accurately determine proper alignment with floor openings without continuous power and clear line of sight.
Innovation Solution
An elevator door safety lock system utilizing a radio frequency identification (RFID) vertical position sensor and a bi-stable solenoid door lock that remains in a stable state until input is received, ensuring doors remain locked during misalignment and unlock when properly aligned, independent of power interruptions, with a control unit coordinating the system's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional safety latches are configured to be either closed or open when energized and move to an opposite state when de-energized, then the locking mechanism can respond to power changes, but the door lock will automatically revert to the de-energized state (unlocking) during power outages, causing safety failures
Solution Approach 1:
The patent inverts the traditional latch behavior by using a bi-stable solenoid that maintains its locked state without continuous power and only changes state when positively triggered. This reverses the conventional approach where the latch defaults to unlocked upon power loss, ensuring safety during power outages by maintaining the locked state unless deliberately changed.
Solution Approach 2:
The system incorporates a bi-stable solenoid with inherent stability in both locked and unlocked states, providing a cushion against power fluctuations. The solenoid's bi-stable nature ensures that temporary power interruptions do not cause unintended state changes, cushioning the system against the harmful effects of power outages before they can cause safety failures.
2Measurement precision
If contact type systems are used to determine proper alignment, then the system can detect alignment status, but the contacts are subject to significant wear over time due to friction, dirt, and corrosion in the elevator shaft environment
Solution Approach 1:
The patent replaces the mechanical contact-type alignment detection system with a magnetic field-based sensing system. Instead of using physical contacts that wear and corrode in the dirty elevator shaft environment, the system uses magnetic fields to detect alignment status, eliminating mechanical wear while maintaining detection accuracy.
Solution Approach 2:
The system introduces a magnetic field as an intermediary between the alignment detection function and the physical environment. The magnetic field penetrates through the dirty and corrosive elevator shaft environment without degradation, serving as a mediator that transmits alignment information without suffering from the harmful effects of the operating environment.
3Ease of operation
If visual indicators such as LEDs or electric eyes are used to indicate elevator positioning, then the system can provide visual feedback, but these indicators are susceptible to power outages and occlusion by dirt and grime in the elevator shaft
Solution Approach 1:
The patent replaces optical visual indicators (LEDs, electric eyes) with magnetic field-based indicators. The magnetic field-based system is not susceptible to occlusion by dirt and grime, and can operate during power outages through the bi-stable solenoid's inherent magnetic field, providing reliable visual feedback without the vulnerabilities of optical systems.
Solution Approach 2:
The system creates an inert magnetic field environment that is immune to the harmful effects of the elevator shaft environment (dirt, grime, moisture). The magnetic field penetrates through these contaminants without degradation, providing a stable and reliable indicator system that maintains functionality regardless of the surrounding environmental conditions.
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 door safety and security during power failures and reduces maintenance needs by avoiding continuous power usage and wear-related issues, while accurately determining alignment without requiring a clear line of sight or continuous power, ensuring safe operation and reduced malfunctions.
Implementation Method 1
bi-stable solenoid door lock that remains in a stable state until input is received
Implementation Method 2
radio frequency identification (RFID) vertical position sensor
Data Source
AI summary
An elevator door safety lock system ensures that an elevator door remains securely closed when it is not aligned with one of a plurality of floor openings. The safety lock system includes a vertical position sensor which includes an RFID reader disposed on the elevator and a plurality of RFID tags each disposed in the shaft at a different floor opening. The reader identifies when it is aligned or non-aligned with any tag indicating when the elevator is aligned and non-aligned with a floor opening. A control unit communicates with the safety lock system and an elevator controller. A door monitor indicates if the elevator door is open or closed and an engagement sensor detects whether the door lock is engaged.