Safety Control Device for People Conveyors
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Solution Overview
Problem
The existing safety systems in people conveyors, such as elevators, are costly and power-inefficient due to the need for multiple independent safety control channels to ensure redundancy, which can lead to increased malfunctions and system unavailability when one channel fails, potentially causing harm to users or damage to the conveyor.
Innovation Solution
A safety control device comprising a first and second safety control channel, along with an override control channel that monitors the health of both and overrides faulty signals to prevent unnecessary activation of safety systems, reducing the complexity and cost of the system while maintaining redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple independent safety control channels are used to ensure redundancy, then system reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple safety control channels into a single integrated safety control device that processes safety signals from multiple sources. Instead of having completely separate control channels, the invention merges them into one device with multiple input interfaces, reducing overall system complexity while maintaining the redundancy needed for safety-critical operations.
Solution Approach 2:
The safety control device is designed to handle multiple types of safety signals and control functions within a single device. It can process signals from various sensors, encoders, and safety systems, providing universal safety control across different functions rather than requiring dedicated control channels for each function.
2Reliability
If multiple independent safety control channels are used to ensure redundancy, then system reliability is improved, but power consumption increases
Solution Approach 1:
The patent combines multiple safety control channels into a single integrated safety control device that processes safety signals from multiple sources. Instead of having completely separate control channels, the invention merges them into one device with multiple input interfaces, reducing overall system complexity while maintaining the redundancy needed for safety-critical operations.
3Reliability
If multiple independent safety control channels are used to ensure redundancy, then system reliability is improved, but component cost increases
Solution Approach 1:
The patent combines multiple safety control channels into a single integrated safety control device that processes safety signals from multiple sources. Instead of having completely separate control channels, the invention merges them into one device with multiple input interfaces, reducing overall system complexity while maintaining the redundancy needed for safety-critical operations.
Solution Approach 2:
The safety control device is designed to handle multiple types of safety signals and control functions within a single device. It can process signals from various sensors, encoders, and safety systems, providing universal safety control across different functions rather than requiring dedicated control channels for each function.
4Reliability
If multiple independent safety control channels are used to ensure redundancy, then system availability is improved, but the probability of channel malfunction increases
Solution Approach 1:
The patent introduces a signal processing unit that acts as an intermediary between multiple safety signal sources and the final safety control output. This intermediary unit consolidates and validates signals from multiple sources, reducing the probability of malfunction by centralizing the control logic and eliminating the need for multiple independent control channels.
Data Source
Figure 1
Figure 2
AI summary
A safety control device (1) for a people conveyor (101). The safety control device (1) comprises a first safety control channel (2) configured to output a first safety control signal in response to one or more input signals (10, 12, 14), a second safety control channel (4) configured to output a second safety control signal in response to one or more input signals (10, 12, 14), and an override control channel (6) configured to: monitor the health of the first and second safety control channels (2, 4), determine whether a fault has occurred in either of the first or second safety control channels (2, 4), and override the first or second safety control signal in response to a determination that a fault has occurred in the corresponding safety control channel (2, 4).