Elevator Safety System Direct Bus Architecture
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Solution Overview
Problem
Current elevator systems require numerous wires to connect safety devices to a central controller for monitoring and bypassing, leading to complex wiring and potential delays in safety signal processing, which can compromise the efficiency and reliability of safety responses.
Innovation Solution
The elevator safety system employs direct communication buses between safety nodes at the hoistway and car locations to the controller, allowing for immediate signal transmission without intermediaries, and a power disconnect mechanism that can bypass the controller to deactivate the propulsion system in case of safety events, reducing the need for extensive wiring and minimizing signal processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discreet conductors are extended from each safety device to the controller for monitoring and bypassing, then safety monitoring capability is improved, but wiring complexity and weight increase significantly
Solution Approach 1:
The patent combines multiple safety device signals into a single safety chain conductor sequence, where each safety device contacts are connected in series along a single conductor path that returns to the controller. This merging approach maintains the ability to monitor all safety devices while eliminating the need for separate discreet conductors from each device, thereby reducing wiring complexity while preserving safety monitoring capability.
2Reliability
If discreet conductors are extended from each safety device to the controller, then safety monitoring capability is improved, but the weight of the traveling cable and hoistway wiring increases
Solution Approach 1:
The patent merges multiple safety signal conductors into a single safety chain conductor that travels with the elevator car. By connecting safety device contacts in series along this single conductor rather than using multiple separate conductors, the overall weight of the traveling cable is significantly reduced while maintaining complete safety monitoring capability across all devices.
3Adaptability or versatility
If multiple intervening nodes are used in the signal path from safety devices to controller, then system modularity is improved, but safety signal processing time increases
Solution Approach 1:
The patent extracts the safety signal path from the general multi-node communication bus architecture and creates a dedicated direct return path for safety signals. The safety chain conductor provides a direct electrical connection from all safety devices back to the controller, bypassing intervening communication nodes and processors, thereby minimizing signal processing time while maintaining system modularity through the separate safety chain infrastructure.
4Reliability
If a traditional safety chain with series-connected contacts is used, then safety reliability is improved, but the number of wires and wiring complexity increase
Solution Approach 1:
The patent merges multiple safety device contacts into a single safety chain conductor sequence where all contacts are connected in series along one continuous conductor path. This approach maintains the high reliability of series-connected safety contacts while reducing the quantity of wires from multiple separate conductors to a single integrated safety chain conductor, thereby solving the contradiction between safety reliability and wire quantity.
Data Source
Figure 1
AI summary
An elevator safety system including a controller, and a hoistway safety node arranged at a pit portion of an elevator hoistway. The hoistway node is operatively connected to one of a pit safety device and a lower hoistway device arranged at the elevator pit. A first bus links the hoistway node and the controller. The first bus passes communication signals directly from the hoistway node to the controller. A car node is arranged in an elevator car. The car node is operatively connected to a car safety device arranged at the elevator car. A second bus links the car node and the controller. The second bus passes communication signals directly from the car node to the controller.