Elevator Safety System Staged Signal Delay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing elevator security systems often result in unnecessary emergency braking when there are temporary issues with position detection, leading to prolonged disruptions and the need for technician intervention.
Innovation Solution
A security system for elevators that includes a safety device capable of transmitting a safety signal to both the safety circuit and the braking device. The safety device delays the transmission of the safety signal to the braking device by a period, allowing for continued operation if the condition causing the safety case is resolved within that time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety signal is transmitted simultaneously to the safety circuit and the braking device, then the response time is minimized and safety is maximized, but unnecessary emergency braking occurs due to temporary position detection issues
Solution Approach 1:
The safety device transmits the safety signal to the safety circuit first (preliminary action), and only after a delay period if the safety condition persists, transmits the signal to the braking device. This staged approach allows temporary position detection errors to resolve without triggering emergency braking, while maintaining safety through the safety circuit's immediate response.
2Reliability
If emergency braking is triggered immediately upon safety event detection, then passenger safety is ensured, but the elevator requires technician intervention and experiences prolonged disruption
Solution Approach 1:
The system dynamically adjusts the response strategy based on the persistence of the safety condition. A delay period is introduced during which the system continues monitoring, allowing transient errors to self-correct. Only if the condition persists beyond the delay period does emergency braking activate, thereby reducing unnecessary downtime while maintaining safety.
3Measurement precision
If the safety device monitors position determination continuously and triggers braking on any error, then measurement precision is maximized, but false alarms occur due to temporary reading errors
Solution Approach 1:
Instead of reacting to every position detection error immediately, the system employs periodic monitoring during a delay period. The safety signal to the braking device is only transmitted if the position determination error persists throughout the entire delay period, thereby filtering out transient reading errors and reducing false alarms.
Data Source
Figure 1
Figure 2
AI summary
The safety system according to the invention is a safety system for an elevator with a cabin which is moved by a drive along a travel path, comprising a safety circuit for switching off the drive in the event of a safety fault, a brake safety device which is designed to brake and hold the cabin in the event of a safety fault, and a safety device which is designed to monitor at least one system of the elevator to be monitored and, in the event of a safety fault in a system to be monitored, to transmit a safety signal to the safety circuit and the brake safety device, wherein the safety device is designed to transmit the safety signal to the safety circuit in a first step and to the brake safety device in a second step, which is delayed by a certain period of time after transmission to the safety circuit.