Elevator Door Monitoring Circuit With Optical Sensor Fault Isolation
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Solution Overview
Problem
Conventional elevator safety apparatuses require frequent maintenance due to susceptibility to high voltage contacts and difficulty in identifying faulty sensors in series circuits, leading to increased maintenance time and costs.
Innovation Solution
A safety apparatus with a first safety circuit and additional sensors that can switch between states, using a decoupled switching unit to control the drive, and optical sensors that operate contactlessly, allowing for improved maintenance and fault detection without interrupting the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrical or electromechanical contacts and switches are used to monitor door closing state, then the safety function is achieved, but the susceptibility to maintenance increases due to high voltage contacts
Solution Approach 1:
The patent divides the safety monitoring system into two separate circuits: a first safety circuit with normally closed switches for emergency stop functions, and a second safety circuit with optical sensors for door monitoring. This segmentation isolates the high-voltage emergency stop circuit from the door monitoring circuit, reducing maintenance complexity and susceptibility.
Solution Approach 2:
The patent replaces electromechanical contacts and switches with optical sensors in the door monitoring circuit. The optical sensors detect door closing state without mechanical contact, eliminating wear and maintenance issues associated with mechanical components while maintaining safety functionality.
2Reliability
If sensors are connected in series to monitor multiple doors, then the safety monitoring is achieved, but the difficulty in identifying faulty sensors increases
Solution Approach 1:
The patent implements a feedback mechanism where the control unit receives signals from all optical sensors and can identify which specific sensor is faulty. The system provides feedback about the status of each individual sensor, enabling easy fault identification and maintenance even when multiple sensors are used in series configuration.
3Ease of repair
If a second safety circuit with optical sensors is introduced, then the maintenance susceptibility is reduced, but the device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it processes signals from the first safety circuit with normally closed switches, processes signals from the second safety circuit with optical sensors, and coordinates the drive control based on both circuits. This multi-functionality consolidates complexity into a single control unit rather than requiring separate control systems.
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 enhances maintenance efficiency by reducing the need for high-voltage contact and enabling easy identification of faulty sensors, thus improving safety and reducing maintenance costs and time.
Implementation Method 1
at least one of the sensors has the following construction: a sensor for safety apparatuses for elevator apparatuses which can move a cab by means of a drive, the sensor being in the form of an optical sensor which comprises a transmitter for transmitting an optical signal and a receiver for receiving the optical signal
Data Source
AI summary
A safety apparatus for elevator apparatuses which can move a cab by way of a drive, including: a first safety circuit, which has a closed conduction state and an open conduction state, with an interrupting apparatus for interrupting the drive depending on the conduction state of the first safety circuit, a safety device, which includes at least two sensors, which can be switched between at least two switching states depending on the closing state of the elevator door. In order to be able to improve the susceptibility to maintenance, a switching unit is provided which can be switched between at least two switching states by connection to the safety device and is designed to effect the closed and/or open conduction state of the first safety circuit.