Elevator Safety Chain Bypass for Single-Technician Shaft Access
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Solution Overview
Problem
Existing elevator systems face challenges in providing safe and easy access for service technicians to electrical safety devices within the shaft, particularly when operational anomalies occur, requiring multiple technicians and posing safety risks during maintenance and inspection operations.
Innovation Solution
An elevator system with a controller that bypasses a portion of the safety chain, allowing manual drive to a position accessible from the car roof, enabling a single technician to repair electrical safety devices safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the limit switch is positioned in the shaft to control elevator safety, then elevator safety is improved, but access for service technicians becomes difficult and requires multiple personnel
Solution Approach 1:
The safety chain is segmented into multiple independent safety devices, allowing selective bypass of specific devices during maintenance while maintaining other safety functions. This enables technicians to access and repair individual limit switches without compromising overall system safety.
Solution Approach 2:
A controller acts as an intermediary to manage the bypass function. The controller receives maintenance requests, selectively excludes specific safety devices from operation, and coordinates the manual drive mode, enabling safe single-technician access to electrical safety devices.
2Ease of repair
If the safety chain is bypassed to enable access to the limit switch, then ease of repair is improved, but safety risks for service technicians increase
Solution Approach 1:
The bypass function is segmented to affect only the specific safety device requiring maintenance rather than the entire safety chain. This localized bypass minimizes safety risks by maintaining other safety functions active during the repair operation.
Solution Approach 2:
The safety chain configuration is dynamically adjusted during maintenance operations. The controller temporarily excludes only the necessary safety device from operation while maintaining other safety functions, creating a dynamic safety profile adapted to maintenance needs.
3Reliability
If multiple service technicians are required for maintenance operations, then safety during repair is improved, but device complexity and operational requirements increase
Solution Approach 1:
The elevator system provides self-service capabilities for maintenance by automatically managing the bypass of safety devices and coordinating manual drive mode through the controller. This eliminates the need for one technician to manually operate the rescue drive switch while another performs repairs.
Solution Approach 2:
The controller accelerates the maintenance process by automatically managing the complex coordination tasks that previously required multiple technicians. The system rapidly and safely handles the bypass configuration and manual drive coordination, reducing personnel requirements.
Data Source
Figure 1~2
Figure 3~4
AI summary
An elevator (100), comprising: an elevator car (10) inside an elevator shaft (1), adapted to transfer passengers and/or cargo between landings (30); an electric drive (4) for operating the elevator car; a manual operating panel (2) disposed inside the elevator shaft for manual drive of the elevator car; an elevator safety chain (50) comprising a controller (110) in connection with plurality of safety devices for monitoring elevator safety; wherein the safety chain comprises an electrical safety device (20; 21) configured to provide information about the elevator car approaching a temporary refuge space (1a; 1b) inside the shaft; and wherein the controller (110) is configured to obtain information from the electrical safety device, and to generate a stopping command (4.1) to stop movement of the elevator car before entering the refuge space. The controller (110) is configured to: in response to a maintenance request of the electrical safety device (20; 21), to exclude the electrical safety device (20; 21) from operation of the elevator safety chain (50), to enable manual drive of the elevator car with the manual operating panel (2). A method for providing access to an electrical safety device (20; 21) of an elevator (100).