Magnetic Elevator Brake Assembly for Car Sag and Bounce
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Solution Overview
Problem
Elevator car sag and bounce due to stretched belts or ropes cause undesirable conditions and trip hazards, and existing safety brakes do not effectively address these issues.
Innovation Solution
An elevator brake assembly with a permanent magnet assembly and an electromagnet assembly that engage one another, controlled by a controller to apply and release a brake pad against the guide rail, reducing sag and bounce through controlled magnetic interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic safety triggers are used for safety brakes, then safety function is improved, but device complexity increases
Solution Approach 1:
The patent combines electromagnetic safety triggers with a permanent magnet assembly into a single integrated brake unit. The electromagnetic trigger and permanent magnet are positioned to work together, where the permanent magnet provides continuous braking force while the electromagnetic trigger provides controlled activation and deactivation, eliminating the need for separate safety brake components.
Solution Approach 2:
The brake assembly serves multiple functions: it acts as both a safety brake and a guide rail brake. The permanent magnet assembly provides continuous braking capability while the electromagnetic trigger provides controlled activation, allowing the same device to handle both safety emergencies and normal operational braking requirements.
2Reliability
If safety brakes are added to prevent sag and bounce, then passenger safety is improved, but device complexity increases
Solution Approach 1:
The patent integrates the safety brake function directly into the guide rail brake assembly. The permanent magnet assembly provides the braking force needed to prevent sag and bounce, while the electromagnetic trigger provides controlled activation. This merged design eliminates the need for separate safety brake mechanisms.
Solution Approach 2:
The permanent magnet assembly provides continuous braking force without requiring external power or control systems. The magnet inherently maintains the braking capability, and the electromagnetic trigger only needs to provide brief activation signals, allowing the system to maintain safety function with minimal external control.
3Force
If existing safety brakes are used, then braking function is provided, but they do not effectively address sag and bounce issues
Solution Approach 1:
The patent changes the fundamental operating parameter from intermittent electromagnetic braking to continuous permanent magnet braking with electromagnetic control. The permanent magnet provides constant magnetic field and braking force, while the electromagnetic trigger modulates the braking intensity by adjusting the magnetic interaction between the trigger and the permanent magnet assembly.
Solution Approach 2:
The brake assembly uses a composite magnetic system combining electromagnetic materials (electromagnetic trigger with coil) and permanent magnetic materials (permanent magnet assembly). This composite approach allows the system to leverage both the controlled activation capability of electromagnets and the continuous force provision of permanent magnets, effectively addressing sag and bounce issues.
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 brake assembly effectively prevents elevator car sag and bounce, providing a cost-effective solution by distributing braking forces through the car frame, ensuring passenger safety and preventing trip hazards.
Implementation Method 1
a permanent magnet assembly and an electromagnet assembly that engage one another
Implementation Method 2
the second magnet is an electromagnet assembly
Implementation Method 3
a coil spring extends between the housing aft end and the bolt head, thereby biasing the second magnet in the aft direction
Data Source
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AI summary
Disclosed is a brake assembly (200) for an elevator system, having: a housing (210) defining a housing cavity (2145), a housing forward end with a forward end opening (2150) into the housing cavity, and a housing aft end; a first magnet (2210) disposed in the housing cavity, near the forward end opening; a second magnet (2230) disposed in the housing cavity, between the first magnet and the housing aft end, and wherein the second magnet is configured to: reduce attraction between itself and the first magnet, whereby the first magnet moves at least partially through the forward end opening to engage a guide rail (109) that is metallic, thereby preventing vertical movement of the first magnet of the brake assembly, when magnetically connected to the rail, relative to the housing; and attract the first magnet to draw the first magnet into the housing cavity.