Elevator Brake Sequencing for Smooth Emergency Stops
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Clutch-type elevator brakes lack control over braking force, leading to abrupt stops during emergency situations, causing discomfort to passengers, and fail to differentiate between normal and emergency stops, resulting in inconsistent braking experiences.
Innovation Solution
An elevator system with a brake control device that selectively delays the engagement of magnetic brakes using residual current from the brake coils, allowing for controlled deceleration and sequencing of brake application to minimize the initial retarding force, thereby smoothing the stop process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If clutch-type brakes are used to stop the elevator, then the braking torque is sufficient to stop the elevator car, but the stop is abrupt and causes jerk to passengers
Solution Approach 1:
The braking system is divided into two separate brakes: a first brake (electromagnetic brake) and a second brake (clutch-type brake). The first brake applies a controlled, lower braking torque initially, while the second brake provides the full stopping torque. This segmentation allows the system to achieve both smooth deceleration and effective stopping without transmitting abrupt forces to the elevator car and passengers.
2Ease of operation
If the same braking torque is applied for both normal and emergency stops, then the braking system is simple to control, but the elevator car and passengers experience jerk every time the braking system is engaged
Solution Approach 1:
The system dynamically adjusts the braking torque by selectively engaging different brakes based on the stopping conditions. For normal stops, only the first electromagnetic brake is engaged providing smooth, controlled deceleration. For emergency stops, both brakes are engaged to provide maximum braking torque. This dynamic adjustment eliminates jerk while maintaining simple control through the brake control device.
3Device complexity
If clutch-type brakes are used, then the braking system is mechanically simple, but it cannot selectively apply different amounts of force for different types of stops
Solution Approach 1:
The braking system achieves multi-functionality by combining two different brake types: the first electromagnetic brake provides smooth, controlled braking for normal operations, while the second clutch-type brake provides high-torque stopping for emergency situations. The brake control device universally controls both brakes, enabling the system to adapt to different stopping requirements (normal stop, emergency stop, door operation) without increasing overall system complexity.
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 a smoother and more comfortable stop for passengers by delaying the engagement of brakes during emergency stops or power loss events, reducing the deceleration rate and minimizing jerk, thus enhancing passenger comfort and safety.
Implementation Method 1
When the brake coil is activated, a magnetic attraction between the armature plates and an electromagnetic core causes the friction pads to disengage from the surface of the brake disk
Implementation Method 2
The first residual current may delay the movement of the first brake to the engaged position by slowing the rate of decay of stored energy within the first brake coil
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An elevator system (20) including a braking system (58), and a method of retrofitting an elevator (20) for such braking system (58) is disclosed. The braking system (58) may comprise a first brake (62) having a first magnetic brake coil (64), the first brake (62) movable between a disengaged and an engaged position, a second brake (66) having a second magnetic brake coil (68), the second brake (66) movable between a disengaged and an engaged position, and a brake control device (60) having a brake power source (94). The brake control device (60) may be electrically connected to the first and second brakes (62, 66) and may be configured to selectively delay or sequence the movement of the first brake (62) and the second brake (66) to the engaged position with residual current from the brake coils (64, 68).