Elevator Safety Wedge Asymmetric Elastic Force Distribution
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Solution Overview
Problem
Existing elevator safety devices, particularly asymmetric arrester devices using disc springs, suffer from poor force repeatability, limited braking capacity, and sensitivity to wedge wear, which can lead to inadequate braking performance and safety hazards, especially in high-speed applications.
Innovation Solution
A safety device for elevators featuring asymmetric active and counter wedges with a U-shaped elastic element and a blocking piece, where the U-shaped elastic element transfers its elastic force to the counter wedge through the blocking piece during braking, enhancing the stability and magnitude of the frictional force for effective braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If multiple disc springs are used to generate elastic force on the counter wedge, then the braking force can be increased, but the force value repeatability deteriorates and working stability is affected
Solution Approach 1:
The elastic element is divided into multiple independent elastic segments (first elastic segment, second elastic segment, etc.), each capable of independently deforming and generating elastic force. This segmentation allows the system to achieve greater total braking force while maintaining better force repeatability through the distributed deformation characteristics of multiple segments.
Solution Approach 2:
The elastic segments are designed to dynamically deform during the braking process, with each segment's deformation amount adjusting based on the braking conditions. This dynamic deformation capability allows the system to adapt to varying friction coefficients and wear conditions, maintaining stable and repeatable braking force generation.
2Device complexity
If the number of disc springs is limited by space restrictions, then the device complexity is reduced, but the braking effect on high-speed elevators becomes inadequate
Solution Approach 1:
The invention changes the parameters of the elastic element by using multiple elastic segments with different deformation capacities. Each segment can be designed with specific elastic coefficients and deformation ranges, allowing the system to generate sufficient braking force for high-speed elevators without requiring an excessive number of components, thus maintaining reasonable device complexity.
3Force
If disc springs with excessively high stiffness and small deformation amount are used, then the elastic force generation is improved, but the sensitivity to wedge wear increases significantly
Solution Approach 1:
The elastic segments are designed with appropriate stiffness and deformation characteristics that allow them to dynamically adapt to wedge wear. As the wedge wears and its position changes, the elastic segments can adjust their deformation amounts accordingly, maintaining stable elastic force generation without being overly sensitive to wear-induced position variations.
Solution Approach 2:
The invention optimizes the elastic parameters of each segment, using segments with different stiffness values and deformation capacities. This parameter diversification allows the system to generate sufficient elastic force while reducing sensitivity to wedge wear, as the distributed elastic segments can compensate for position variations caused by wear.
4Force
If the elastic force generated by disc springs decreases significantly due to wedge wear, then the desired frictional force becomes hard to achieve, but maintaining high elastic force requires excessive stiffness
Solution Approach 1:
The elastic element is segmented into multiple independent units that can deform differently based on wear conditions. When wear occurs, the segments can redistribute their deformation, ensuring that the total elastic force remains relatively stable and continues to generate the desired frictional force without requiring excessively high individual segment stiffness.
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 stable and repeatable braking force, improving the safety and reliability of elevator operations by reducing sensitivity to wedge wear and enabling effective braking even at high speeds, while maintaining a self-adjustable frictional force to accommodate varying friction coefficients.
Implementation Method 1
a U-shaped elastic element elastically acts on an upper end surface of the blocking piece, and transfers, through the blocking piece during the at least part of the braking process, at least part of an elastic force of the U-shaped elastic element to the counter wedge
Implementation Method 2
the arrestment similar to braking is caused by a frictional force between the wedge and the guide rail of the elevator, where the magnitude of the frictional force reflects the magnitude of an arresting force exerted on the guide rail
Data Source
AI summary
The present invention provides a safety device for elevators, which belongs to the field of elevator safety technologies. The safety device for elevators includes a housing; a safety piece having a guide rail groove, the safety piece being disposed in the housing; and asymmetric active and counter wedges that are slidably disposed on the safety piece at both sides of the guide rail groove, respectively. Moreover, the device further includes a U-shaped elastic element and a blocking piece that are disposed on the safety piece. The safety device for elevators can provide a relatively stable arresting force, is reliable in repetitive work, achieves high safety, is relatively easy as well as fast and efficient in restoration, and is especially suitable for high-speed elevators.