Elevator Brake Plunger Layout to Prevent Hard Stops
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Solution Overview
Problem
Elevator brakes with two brake discs and two plungers can cause hard stops when both plungers malfunction, compromising safety and passenger comfort.
Innovation Solution
An elevator brake system with three movable plungers and two brake discs, utilizing a serial configuration of springs and solenoids to ensure redundancy and independent engagement with brake discs, preventing hard stops even in the event of a plunger malfunction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two brake discs and two plungers are used to enhance safety redundancy, then reliability is improved, but hard stops occur when both plungers malfunction simultaneously
Solution Approach 1:
The brake system is segmented into two independent braking circuits, each with its own plunger and spring assembly. This segmentation ensures that a malfunction in one circuit does not necessarily cause both plungers to engage simultaneously, preventing hard stops while maintaining safety redundancy.
Solution Approach 2:
The system incorporates a plunger stop mechanism that limits the maximum engagement distance of plungers. This beforehand cushioning prevents excessive braking force even when plungers malfunction, avoiding hard stops while maintaining adequate braking capability for safety.
2Reliability
If two plungers are moved into frictional engagement with brake discs for reliable braking, then braking reliability is improved, but brake linings suffer from increased wear
Solution Approach 1:
The braking system divides the braking function across two independent plunger-brake disc contact points. Each plunger engages with its respective brake disc separately, distributing the wear across multiple contact surfaces and extending the overall system lifetime while maintaining reliable braking.
Solution Approach 2:
The system allows for selective replacement of individual brake linings and plungers based on wear patterns. By monitoring and maintaining each component independently, the system can recover and extend the overall brake assembly lifetime without replacing the entire system.
3Force
If two springs are arranged in series to apply braking force, then braking force distribution is improved, but the system complexity increases
Solution Approach 1:
The spring assembly is segmented into two independent spring units, each associated with its own plunger. This segmentation simplifies the overall system architecture compared to a complex multi-spring arrangement, while still providing distributed braking force application across both brake discs.
Solution Approach 2:
Each spring-plunger assembly serves multiple functions: it provides braking force, acts as a safety redundancy element, and includes inherent stop mechanisms. This multi-functionality reduces the need for additional separate components, thereby reducing overall system complexity despite the series arrangement.
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
Ensures reliable braking and extended brake disc lifetime by allowing independent plunger engagement, preventing hard stops and protecting brake linings from wear, enhancing safety and reliability.
Implementation Method 1
Each of the at least two springs is configured for applying a spring force to at least two of the at least three movable plungers for urging the at least one movable plunger towards at least one of the brake discs for engaging the elevator brake
Implementation Method 2
Each of the at least two springs is configured for applying a spring force to at least two of the at least three movable plungers for urging the at least one movable plunger towards at least one of the brake discs for engaging the elevator brake
Implementation Method 3
Each of the at least two solenoids is associated with a respective one of the at least two springs and configured for producing a counterforce directed against the respective spring force applied by the respectively associated spring such as to urge the respective at least one movable plunger in the axial direction away from the respective brake disc
Implementation Method 4
Each of the at least two solenoids is associated with a respective one of the at least two springs and configured for producing a counterforce directed against the respective spring force applied by the respectively associated spring such as to urge the respective at least one movable plunger in the axial direction away from the respective brake disc
Implementation Method 5
The at least three movable plungers include a first plunger, a second plunger and a third plunger. The at least three movable plungers are movable along the axial direction for selectively engaging or releasing the elevator brake
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
An elevator brake (20) for braking rotation of a shaft (12) in an elevator drive system (5) comprises at least two brake discs (24a, 24b) mounted to the shaft (12) such as to rotate concurrently with the shaft (12); at least three movable plungers (28a, 28b, 30), which are movable along the axial direction (A) for selectively engaging or releasing the elevator brake (20); and an actuator. The actuator comprises at least two springs (36a, 36b) configured for applying a spring force to at least one of the at least three movable plungers (28a, 28b, 30) for urging the at least one movable plunger (28a, 28b, 30) towards at least one of the brake discs (24a, 24b) for engaging the elevator brake (20); and at least two solenoids (38a, 38b) for producing a counterforce directed against the respective spring force applied by a respectively associated spring (36a, 36b) such as to urge the respective at least one movable plunger (28a, 28b, 30) in the axial direction (A) away from the respective brake disc (24a, 24b). The at least two springs (36a, 36b) are arranged in series to each other along the axial direction (A).