Elevator Safety Brake Actuator Cover for Clearance Gap Protection

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Solution Overview

Problem

Safety brake actuators in elevator systems face reliability issues due to foreign objects entering the clearance gap between the actuator and the guide rail, which can impede their operation, especially when these objects are ferromagnetic and get stuck to magnets, disrupting friction or actuation mechanisms.

Innovation Solution

Incorporating an object-diverting arrangement, such as a magnet or structural barrier, positioned relative to the clearance gap to prevent or capture foreign objects, which can include a permanent or electromagnet to attract ferromagnetic objects or a cover that adapts to maintain a reduced width of the gap, ensuring foreign objects are diverted or deflected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the clearance gap between the safety brake actuator and guide rail is maintained for proper operation, then the actuator can function correctly, but foreign objects can enter the gap and cause reliability issues

Engineering Contradiction:

Improvereliability of safety brake actuatorVSAvoidforeign object entry into clearance gap

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A cover is introduced as an intermediary element between the clearance gap and the external environment. The cover includes a slot that accommodates the guide rail while preventing foreign objects from entering the clearance gap, thus protecting the actuator mechanism without interfering with its operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cover acts as a protective shell that encloses the clearance gap area. It is designed with flexibility to accommodate the guide rail movement while maintaining protection against foreign object intrusion, effectively isolating the critical clearance gap from harmful external factors

Inventive Principle:

Principle #30Flexible shells and thin films

2Force

If magnets are used in the actuation mechanism to engage the safety brake, then braking force is generated, but ferromagnetic foreign objects get stuck to the magnets and disrupt operation

Engineering Contradiction:

Improvebraking forceVSAvoidoperation reliability disrupted by ferromagnetic objects

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The cover serves as a mediator that blocks ferromagnetic foreign objects from reaching the magnets inside the actuation mechanism. By positioning the cover between the external environment and the magnets, it prevents objects from getting stuck on the magnets while allowing the magnetic braking force to function normally

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful effect of ferromagnetic object attraction is extracted and isolated from the main actuation mechanism by introducing the cover as a separate protective element. This removes the vulnerability of the magnets to foreign object interference while preserving their braking function

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If the clearance gap is reduced to prevent foreign object entry, then object entry is impeded, but the actuator may not accommodate guide rail variations

Engineering Contradiction:

Improveforeign object entry preventionVSAvoidaccommodation of guide rail variations

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The cover is segmented with a slot that specifically accommodates the guide rail, separating the function of guiding the rail from the function of preventing foreign object entry. This segmentation allows the clearance gap to be minimized for protection while the slot provides the necessary adaptability for guide rail variations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover exhibits local quality by having different functional zones: the slot area provides adaptability and guide rail accommodation, while the surrounding cover structure provides foreign object protection. This localized differentiation resolves the contradiction between protection and adaptability

Inventive Principle:

Principle #3Local quality

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 object-diverting arrangement enhances the reliability of safety brake actuators by preventing foreign objects from interfering with their operation, maintaining proper functioning and ensuring timely engagement of the safety brake, even in emergency situations.

Implementation Method 1

Some other ESA's use a different mechanism other than a friction interaction between a magnet and the guide rail to actuate the safety brake. For example, in some frictionless electronic safety actuators, a spring force is controlled to pull on a linkage that engages a safety brake.

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentUS11970367B2Safety brake actuator

Publication Date: 2024.04.30 OTIS ELEVATOR CO

AI summary

An elevator system includes a guide rail, an elevator car, a safety brake actuator and a safety brake. The safety brake actuator and the safety brake are mounted to the elevator car to move along the guide rail with the elevator car in use. The safety brake actuator includes an actuation mechanism configured in use to actuate the engagement of the safety brake against the guide rail. The safety brake actuator also includes a proximal surface, the safety brake actuator is mounted adjacent to the guide rail with the proximal surface facing the guide rail and spaced from the guide rail to define a clearance gap between the guide rail and the proximal surface of the safety brake actuator.