Hydraulic Elevator Open-Door Safety Device with Two-Stage Threshold Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic elevators are prone to excessive speed due to vibrations, leading to erroneous braking operations and increased deceleration, which can result in passenger injury, as existing open-door running prevention units lack tolerance for car shaking caused by passengers.
Innovation Solution
A safety device for hydraulic elevators that includes an open-door running prevention unit and a pressure sensor to detect car speed and pressure changes, calculating a differential value between maximum and minimum pressure values to determine abnormality and initiate braking only when the speed exceeds a preset threshold, thereby reducing deceleration and stopping distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the abnormality detection speed is set with a tolerance for car shaking, then the open-door running prevention unit is prevented from being erroneously operated, but the deceleration of the car is undesirably increased
Solution Approach 1:
The patent segments the speed threshold into two distinct levels: a first threshold value for initial detection and a second threshold value (higher than the first) for confirming abnormality. This segmentation allows the system to tolerate normal shaking speeds while detecting true abnormalities, preventing erroneous operations without requiring excessive tolerance that would increase deceleration.
Solution Approach 2:
The system dynamically adjusts its detection criteria based on the relationship between car speed and pressure differential. By using a two-stage threshold system where the second threshold is higher than the first, the system adapts its sensitivity to distinguish between normal shaking and true abnormalities, maintaining reliability while minimizing unnecessary braking and associated deceleration.
2Reliability
If the abnormality detection speed is set with a tolerance, then false braking is prevented, but the maximum speed of the car increases until braking starts
Solution Approach 1:
The patent divides the detection process into two stages with different threshold values. The first threshold detects potential issues at lower speeds, while the second (higher) threshold confirms true abnormalities. This prevents false braking during normal shaking while enabling timely detection of real problems, avoiding the need to set the threshold so high that maximum car speed increases excessively.
Solution Approach 2:
The system uses feedback from both speed sensors and pressure differential measurements to continuously monitor car behavior. By comparing real-time data against the two-threshold system, the system can distinguish between normal shaking and true abnormalities, preventing false braking operations while maintaining appropriate maximum speed limits through continuous monitoring and adjustment.
3Reliability
If the abnormality detection speed is set with a tolerance, then the open-door running prevention unit avoids erroneous operation, but the stopping distance increases
Solution Approach 1:
The patent implements a two-stage threshold system where the first threshold is lower and the second threshold is higher. This segmentation enables the system to detect potential issues early while confirming true abnormalities before triggering braking. The result is reliable operation without excessive tolerance that would extend stopping distance, as the system responds appropriately to confirmed abnormalities without unnecessary delays.
Solution Approach 2:
The system continuously monitors both speed and pressure differential with feedback control. By using the two-threshold system with feedback from sensors, the system can distinguish between normal shaking and true abnormalities, initiating braking only when necessary. This maintains reliability while minimizing stopping distance by avoiding unnecessary braking delays associated with excessive tolerance settings.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively detects abnormal downward movement states at lower speeds, reducing car deceleration and stopping distance while preventing passenger injury by distinguishing between car shaking and actual abnormalities, thus providing a safer and more controlled braking process.
Implementation Method 1
a pressure sensor, which is configured to detect a pressure value on a side of a check valve provided in a hydraulic pipe
Data Source
AI summary
A safety device for a hydraulic elevator includes an open-door running prevention unit and a pressure sensor. The open-door running prevention unit includes a memory configured to sequentially store values of the pressure sensor during a period in which the hydraulic elevator is in the open-door state as time-series data. When it is determined that the car speed, detected when the hydraulic elevator is in the open-door state, is equal to or larger than a preset first threshold value, the open-door running prevention unit calculates a differential value between a maximum value and a minimum value of the time-series data stored in the memory in a period of a preset determination time. When the differential value is out of a preset allowable range, the open-door running prevention unit determines that the open-door running abnormality is present, and executes the car braking processing.