Elevator Car Door Backup Braking for Smooth Power-Failure Closing
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Solution Overview
Problem
Existing elevator door closing mechanisms during power failures result in sharp acceleration and noise due to the lack of power-assisted braking, and existing solutions like friction brakes or motor generators are costly or require motor redesign.
Innovation Solution
A method and device that utilize an electrical buffer storage to provide controlled backup energy to the door drive, allowing it to function as a dynamic brake during power failures, using a capacitor or battery to store energy during normal operation and release it to control the door's closing movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical energy storage device (spring or tensioning weight) is used to close the door during power failure, then the door can close without power, but the door accelerates sharply and hits the door stop causing high noise development
Solution Approach 1:
The patent introduces an intermediary braking mechanism between the mechanical energy storage device and the door. This brake acts as a mediator that controls the energy release, preventing sharp acceleration and noise while still enabling door closure during power failure. The brake is integrated into the existing door drive mechanism, allowing controlled dissipation of mechanical energy.
Solution Approach 2:
The patent converts the potentially harmful sharp acceleration and impact into a controlled braking process. By using the door drive motor as a dynamic brake during power failure, the mechanical energy that would cause noise is instead converted into controlled rotational deceleration, transforming a harmful effect into a beneficial controlled closure.
2Object-generated harmful factors
If a friction brake is equipped on the door to avoid noise development, then noise is reduced, but additional costs are incurred
Solution Approach 1:
The patent makes the door drive motor multi-functional by enabling it to operate as a dynamic brake during power failures. This eliminates the need for a separate friction brake component, as the motor itself performs both its normal driving function and the braking function, reducing overall system cost while maintaining noise reduction benefits.
Solution Approach 2:
The door drive motor serves itself by using its own electromagnetic structure to provide braking action during power failures. The motor's field windings and armature interact to create electromagnetic braking without requiring external brake components, making the system self-sufficient and cost-effective.
3Object-generated harmful factors
If the drive motor is permanently connected as a generator during power failure to use as a dynamic brake, then noise is reduced, but a special design of the drive motor is required
Solution Approach 1:
The patent implements a dynamic switching mechanism that changes the motor's operational mode based on power availability. During normal operation, the motor functions as a standard actuator. During power failure, the control system dynamically reconfigures the motor connections to enable regenerative braking, allowing the same motor to adapt its function without special design modifications.
Solution Approach 2:
The patent changes the electrical parameters and connection configuration of the drive motor depending on the power supply status. By altering the motor's operational parameters (from motor mode to generator/brake mode) through control electronics, the system achieves dynamic braking functionality without requiring a specially designed motor, maintaining compatibility with standard motors.
4Device complexity
If no braking mechanism is used during power failure, then the system remains simple, but the door hits the door stop causing high noise and wear
Solution Approach 1:
The patent replaces a purely mechanical braking approach with an electromagnetic braking mechanism using the door drive motor. This substitution allows for more controlled and adjustable braking action compared to mechanical friction brakes, achieving better noise and wear reduction while maintaining system simplicity through the reuse of existing electromagnetic components.
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 provides a cost-effective and easy-to-retrofit mechanism that gently controls the door's closing movement, reducing noise and wear by alternating power supply to the door drive, ensuring smooth operation during power outages.
Implementation Method 1
A device (122) having a control electronics (124) and an electrical energy store (126) is looped into an energy line (120) between the energy supply (112) and the control device (110). The energy store (126) is charged as long as the supply voltage (114) is present. If the supply voltage (114) fails, the stored energy is released in a controlled manner by the control electronics (124) to the control device (110).
Implementation Method 2
using a capacitor or battery to store energy during normal operation and release it to control the door's closing movement
Implementation Method 3
the door drive (106) can function as a dynamic brake during power failures
Data Source
AI summary
A method for controlling a closing movement of a door of an elevator car in the event of a power failure uses the door drive and an electrical energy store. During normal operation of the door by the door drive, electrical energy is buffered in the energy store. In response to a power failure when the door is open, a closing mechanism begins to close the door and the stored electrical energy is provided as backup energy to the door drive by a control device to decelerate the closing movement.