Multi-car elevator failure management
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Solution Overview
Problem
Conventional multi-car elevators with circulating type and omnidirectional designs face challenges in degraded operation, where a failed cage prevents other cages from moving between shafts, limiting passenger transport to all floors, especially when a failure occurs at the highest or lowest floor, and requires stopping all cages except at maintenance and standby floors.
Innovation Solution
A control device with failure detection and mode switching capabilities assigns stop floors to remaining operational cages, allowing them to operate between the highest and lowest floors, enabling efficient passenger transport by determining optimal transfer floors and using additional elevators or shuttle elevators to facilitate transfers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional degraded operation is applied to a circulating type multi-car elevator, then a failed cage is withdrawn to upper or lower floor, but other normally operating cages cannot move to one shaft from another at upper or lower regions
Solution Approach 1:
The patent dynamically reconfigures the circulation path of cages based on failure detection. When a cage fails, the system switches from a fixed circulation pattern to a flexible assignment mode where remaining cages are dynamically assigned to serve different floor ranges and shaft configurations, enabling continued operation despite structural changes in the system
Solution Approach 2:
The control device changes operational parameters by detecting cage failure positions and adjusting the circulation control accordingly. The system modifies which shafts and floors are active for remaining cages, transforming the operational state from normal multi-shaft circulation to a degraded single-shaft or limited-shaft configuration
2Reliability
If a failure cage is present in a shaft, then other cages in the same shaft cannot stop at floors near the failure location, but this limits passenger transport to all floors
Solution Approach 1:
The patent segments the service area into multiple zones based on failure location. Remaining cages are assigned to serve specific floor ranges (e.g., one cage serves floors 1-10, another serves floors 5-20), allowing comprehensive floor coverage while maintaining safe distances from failure zones. This segmentation enables continuous passenger transport across all floors despite local restrictions
Solution Approach 2:
The control device acts as an intermediary that coordinates cage assignments and transfer floor selections. It mediates between the constraint of failure zones and the need for comprehensive service by optimizing which cages stop at which floors and managing transfers between cages to ensure all floors remain accessible
3Reliability
If all cages must stop when a cage fails at non-maintenance floors, then safety is maintained but operation efficiency is reduced
Solution Approach 1:
The system performs preliminary failure detection and automatic mode switching before complete operation shutdown is required. By detecting cage failures early and automatically reconfiguring cage assignments, the system maintains continuous operation of remaining cages without requiring full stops or manual intervention, minimizing operation interruption while ensuring safety
Data Source
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AI summary
A multi-car elevator composed of two or more shafts (2L, 2R) and having a plurality of cages (3a, 3c) moving in the same shaft vertically is provided. The multi-car elevator includes: a failure detecting unit (6) that detects failure in the cages (3a, 3b, 3c) and a position in which failure is caused; an operating mode switching unit (7) for switchover to degrade operation for service of those cages (3a, 3b, 3c) in which failure is not detected, in the case where failure is detected; and a cage stop floor assigning unit (11) that assigns a stop floor to each cage (3a, 3b, 3c) between a highest floor or a lowest floor and that position in which the failure is caused. In the case where switchover to the degraded operation is made and a hall call is generated, a cage is assigned to service, the cage having been assigned as the stop floor to a floor called by the hall call.