Traction Sheave Brake Block Layout for Adaptive Emergency Stopping
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Solution Overview
Problem
Existing safety devices for stopping the traction sheave in elevator systems are large, require high installation accuracy, and have complex installation procedures, with inadequate adjustment of frictional braking force according to rotating speed, leading to potential accidents during abnormal elevator operations.
Innovation Solution
A traction sheave safety device comprising a pair of brake block components with adjustable frictional braking force, triggered by an actuation component that cuts off the safety circuit when abnormal operation is detected, allowing for automatic regulation of braking force based on rotating speed and simple installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic drum brake is used to stop the traction sheave, then the emergency braking function is achieved, but the device size becomes large and installation accuracy requirements increase
Solution Approach 1:
The brake shoe is divided into two separate brake blocks, each independently clamping onto the traction sheave. This segmentation allows for a more compact overall structure while maintaining the necessary braking force, directly addressing the device size and complexity issue while preserving emergency braking reliability
Solution Approach 2:
The patent combines the electromagnetic actuation mechanism with the brake block assembly into an integrated unit. The electromagnetic iron core directly actuates the brake blocks without requiring separate mechanical linkages, reducing the overall device size and simplifying installation while maintaining effective emergency braking capability
2Ease of operation
If fixed frictional braking force is applied, then the braking action is simple, but the braking force cannot be adjusted according to rotating speed causing potential accidents
Solution Approach 1:
The brake spring is designed with variable elasticity characteristics, providing different braking forces at different stages of compression. During normal operation, the spring maintains light contact pressure for smooth operation, while during emergency braking, the spring's progressive compression generates increasingly strong braking force to match the high rotating speed conditions, eliminating the need for complex adjustment mechanisms
Solution Approach 2:
The patent changes the elastic parameter of the brake spring to achieve variable braking force. The spring's force-displacement characteristics are specifically designed so that the braking force automatically increases with the compression distance, which correlates with the rotating speed of the traction sheave. This provides adaptive braking force adjustment without additional complexity
3Force
If brake blocks are positioned close to the traction sheave, then strong electromagnetic force can be generated, but the side clearances must be very small requiring high installation accuracy
Solution Approach 1:
The brake blocks are positioned asymmetrically relative to the traction sheave, with the electromagnetic iron core aligned to generate force primarily on one side. This asymmetric arrangement allows for larger clearance on the non-critical side while maintaining sufficient electromagnetic force on the critical side, reducing the overall installation accuracy requirements
Solution Approach 2:
The brake blocks are pre-positioned with initial clearance from the traction sheave surface. During normal operation, this clearance prevents contact and wear. During emergency braking, the electromagnetic force overcomes this initial clearance and generates the necessary braking force. This preliminary positioning allows for larger tolerances while maintaining effective braking capability
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 device effectively stops the traction sheave with adjustable braking force, ensuring safety during abnormal operations while being compact, cost-effective, and easy to install, reducing the risk of accidents and improving overall performance.
Implementation Method 1
the frictional braking force generated between the brake rubber of the device and the traction sheave
Implementation Method 2
an electromagnetic drum brake that is actuated electromagnetically
Data Source
AI summary
A method includes a first brake block of a first brake rubber, a second brake block mounted with a second brake rubber and a mounting base for mounting the first and second brake blocks. The second brake rubber is movable along a direction slanted with respect to an axis of rotation of the traction sheave. A brake block actuation member is triggered by the brake blocks to enable the first and the second brake rubbers to hold the traction sheave. A switching member is also triggered by the action of the second brake rubber, cutting off a safety circuit of the elevator. The external power is cut off, and the brake block actuation member enables contact between the second brake rubber and the traction sheave. The traction sheave further drives the second brake rubber triggering the brake block members to generate frictional braking force to stop the traction sheave.