Elevator Safety Gear with Dynamic Braking Force Control
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Solution Overview
Problem
Elevator safety gear systems in high-rise buildings face challenges in maintaining a consistent deceleration range due to varying loads from compensation ropes and cables, leading to risks of excessive deceleration or failure to stop, which can result in passenger injuries or system failure.
Innovation Solution
A safety gear system with a main static mass, an auxiliary static mass, and a dynamically changing mass, where the second safety gear applies an adjustable brake force based on the changing mass, allowing for deceleration adjustments to maintain a safe range of 0.2 g to 1.0 g across elevator travel, reducing risks of injury and system failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant braking force is applied by safety gears, then the safety gear structure is simple and easy to manufacture, but the deceleration varies with changing load mass leading to inconsistent stopping performance
Solution Approach 1:
The patent applies the dynamics principle by making the braking force adjustable rather than constant. The braking force is dynamically adjusted based on the current load mass through a sensor that detects the mass of the elevator car and cable system, and a control unit that modifies the braking force accordingly. This resolves the contradiction by enabling consistent deceleration performance across varying loads while accepting increased system complexity.
Solution Approach 2:
The patent implements parameter changes by varying the braking force parameter in response to changes in load mass. The control unit receives mass information from the sensor and adjusts the braking force parameter to maintain optimal deceleration within the specified range (0.2g to 1.0g) regardless of whether the elevator is lightly or heavily loaded.
2Reliability
If braking force is increased to ensure sufficient deceleration at top position, then deceleration at top is adequate, but deceleration at bottom exceeds safe limits causing passenger injury risk
Solution Approach 1:
The patent uses parameter changes to adjust the braking force based on the elevator's position and load conditions. When the elevator is at the top with heavy cable mass, a higher braking force is applied. When at the bottom with lighter cable mass, the braking force is reduced. This dynamic parameter adjustment ensures deceleration remains within the safe range (0.2g to 1.0g) at all positions, preventing both inadequate and excessive deceleration.
Solution Approach 2:
The patent implements feedback by using a sensor to continuously monitor the mass of the elevator car and cable system, transmitting this information to a control unit that adjusts the braking force accordingly. This closed-loop feedback mechanism ensures that the braking force is always appropriate for the current load conditions, preventing excessive deceleration that could injure passengers while ensuring sufficient deceleration when needed.
3Reliability
If safety gear is adjusted for minimum deceleration (0.2g) at top position, then stopping is guaranteed, but the system cannot accommodate high-rise buildings where cable mass variation is significant
Solution Approach 1:
The patent applies parameter changes by making the braking force adjustable based on the actual load mass. In high-rise buildings where cable mass varies significantly, the sensor detects the actual mass, and the control unit adjusts the braking force parameter to maintain optimal deceleration. This enables the safety gear system to be universally applicable to both low-rise and high-rise buildings, maintaining stopping guarantee while adapting to different building heights and cable mass variations.
Solution Approach 2:
The patent uses dynamics by transitioning from a static, fixed braking force system to a dynamic system that continuously adapts to changing load conditions. The sensor and control unit enable real-time detection and adjustment of braking force, making the system versatile enough to handle the significant cable mass variations in high-rise buildings while maintaining reliable stopping performance.
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 system ensures consistent deceleration within safe limits, preventing passenger injuries and system failures by dynamically adjusting brake force with travel position, maintaining deceleration below 1 g when necessary and above 0.2 g when required, thus enhancing safety and reliability in high-rise elevators.
Implementation Method 1
The safety gear system comprises at least a first safety gear which is configured to brake the auxiliary static mass by a constant braking force, and at least a second safety gear which is configured to brake the main static mass and the dynamically changing mass by an adjustable brake force
Data Source
AI summary
A safety gear system for an elevator has a main static mass, an auxiliary static mass and a dynamically changing mass, wherein the dynamically changing mass changes in accordance with the travel of the main static mass. The safety gear system includes at least one first safety gear which is configured to brake the auxiliary static mass by a constant braking force, and at least one second safety gear which is configured to brake the main static mass and the dynamically changing mass by an adjustable brake force which is adjustable in accordance with the change of the dynamically changing mass.