Elevator Safety Device Holding Force Adjustment
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Solution Overview
Problem
Elevator safety devices consume excessive energy due to the need for continuous energization of electromagnets to prevent unintentional activation, especially in infrequently used systems, leading to increased operating costs and maintenance requirements.
Innovation Solution
A safety device with a holding element that adjusts its holding force based on operating modes, allowing a reduced tolerance amount during rest modes to minimize energy consumption while maintaining safety during travel modes by varying the magnetic force provided by electromagnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electromagnet is permanently energized to prevent unintentional activation of the safety device, then the safety and reliability of the elevator system is improved, but the energy consumption increases significantly
Solution Approach 1:
The holding force of the electromagnet is made dynamically adjustable based on the operational state of the elevator system. During travel modes, a first holding force (first tolerance amount) is applied to ensure safety during movement. During rest modes, a second holding force (second tolerance amount) is applied to reduce energy consumption. This dynamic adjustment resolves the contradiction between maintaining constant safety and reducing continuous energy usage.
Solution Approach 2:
The magnetic holding force parameter is changed based on operational conditions. The system switches between different holding force levels (first tolerance amount during travel, second tolerance amount during rest) to optimize the balance between safety requirements and energy consumption, allowing the electromagnet to operate at reduced power when full holding force is not needed.
2Reliability
If the holding force is increased to avoid unintentional activation during operation, then the reliability is improved, but the energy consumption increases due to the need for higher magnetic force
Solution Approach 1:
The holding force is dynamically adjusted based on whether the system is in travel mode or rest mode. During travel modes, the higher first holding force ensures reliability by preventing unintentional activation despite vibrations and movements. During rest modes, the lower second holding force suffices since the system is stationary, thereby reducing energy consumption while maintaining adequate reliability for the operational context.
Solution Approach 2:
The magnetic holding force parameter is varied according to operational state. The control device switches between a first holding force level during travel (when higher reliability is needed to counteract vibrations and movements) and a second holding force level during rest (when lower force is sufficient), optimizing the balance between reliability and energy consumption.
3Loss of energy
If the electromagnet is switched off to reduce energy consumption, then the energy efficiency is improved, but the safety device may be unintentionally activated
Solution Approach 1:
The electromagnet operates in periodic cycles rather than continuously. During travel modes, it maintains the first holding force to ensure safety. During rest modes, it reduces to the second holding force to improve energy efficiency. This periodic adjustment of the holding force level allows the system to alternate between safety-critical operation and energy-efficient operation, resolving the contradiction between continuous energization and energy savings.
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
This approach reduces energy consumption and extends the service life of the holding element by adapting the holding force to the operational needs of the elevator system, ensuring safe operation while minimizing unnecessary energy usage.
Implementation Method 1
An electromagnet is frequently used to provide the holding force, the magnetic force of which electromagnet is greater than the driving force and is at least partially opposed to the driving force
Implementation Method 2
An electromagnet with a power consumption of between 50 W and 500 W can be suitable for use within the scope of a holding element
Data Source
AI summary
A safety device for an elevator system may include a safety element that in a release position holds a safety system in a deactivated state and in a blocking position activates the safety system. The safety element may exert a driving force configured to transfer the safety element from the release position into the blocking position. A holding element may exert a holding force on the safety element that counteracts the driving force to hold the safety element in the release position. In the release position of the safety element, the holding force exceeds the driving force by a tolerance amount that is adjustable depending on different operating modes that are possible in the release position of the safety element. The safety device may be configured to transfer the safety element into the blocking position, to reduce the holding force such that the driving force exceeds the holding force.