Elevator Shaft Door Locking Signal Sequence Verification
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Solution Overview
Problem
There is a need for a safety measure to ensure that personnel have left the elevator shaft after maintenance work before the elevator system resumes normal operation, as existing systems lack a reliable method to verify the absence of personnel before switching back to regular driving mode.
Innovation Solution
A control device with a controller and memory that receives signals from the shaft door locking device, comparing a temporal sequence of locking and unlocking signals with a stored reference sequence to determine when maintenance mode can be ended, ensuring personnel have exited the shaft before resuming normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the elevator system switches back to regular driving operation immediately after maintenance mode, then operational efficiency is improved, but safety is compromised because personnel presence in the shaft cannot be verified
Solution Approach 1:
The system performs preliminary verification of personnel absence by monitoring the locking device signal sequence before allowing the elevator to resume operation. The controller checks whether the shaft door was locked and unlocked in a specific pattern indicating personnel exit, and only after this verification does it permit transition from maintenance mode to regular operation, thus ensuring safety before productivity improvement
Solution Approach 2:
The system uses feedback from the locking device signal sequence to determine whether personnel have left the shaft. The controller continuously monitors the locking/unlocking signals and compares them against the reference sequence stored in memory. When the signal sequence matches the reference pattern, the controller receives feedback that personnel have exited, and automatically transitions the system from maintenance mode to regular operation
2Reliability
If a safety verification system is implemented to check personnel absence, then safety is improved, but device complexity increases due to additional control logic and signal monitoring
Solution Approach 1:
The system uses the existing locking device and its signal output to verify personnel absence. The locking device itself provides the verification function by generating signals that the controller monitors. No separate detection device is needed - the existing component serves the dual purpose of door locking and personnel presence verification, thus improving safety without significantly increasing device complexity
Solution Approach 2:
The locking device serves multiple functions: it locks the shaft door for safety during maintenance, generates signals for control system monitoring, and provides the verification basis for determining personnel absence. The controller also performs multiple functions by both monitoring the signal sequence and controlling the drive operation. This multi-functionality reduces the need for additional dedicated components
3Reliability
If the locking device signal sequence is monitored to verify personnel exit, then safety is improved, but time is lost due to the verification process before resuming operation
Solution Approach 1:
The controller monitors the locking device signals in periodic intervals during maintenance mode. Rather than requiring a lengthy continuous verification process, the system checks the signal sequence at periodic moments. When the reference pattern is detected, the transition to regular operation is triggered immediately, minimizing the time loss while maintaining safety verification
Data Source
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AI summary
The invention relates to a control unit (10) and to an elevator-monitoring apparatus (50) and to a method for monitoring a maintenance mode of an elevator installation (100). The control unit (10) has a controller (12) and a memory device (14), wherein the controller (12) is designed to receive a first signal when a locking device (18) of shaft door (16) is locked and to receive a second signal when the locking device (18) is unlocked. The controller (12) is also designed to compare a chronological signal sequence of first signals and second signals with a reference sequence stored in the memory device (14) for actuation of the locking device (18) and, if the signal sequence of the first signals and second signals matches the reference sequence, to end the maintenance mode and to release a car (52) of the elevator installation (100) for a traveling operation.