Fail-Safe Safety Brake Actuation for Simplified Hoisted Structures

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Solution Overview

Problem

Existing braking systems for hoisted structures, such as elevators and cranes, are complex and require multiple components like governors, tension devices, and safety actuation modules, which complicate the actuation of braking mechanisms, necessitating a simpler and more reliable solution.

Innovation Solution

A safety brake actuation mechanism featuring a housing with cam and brake members that move between braking and non-braking positions, utilizing an electric actuator and biasing member to overcome spring force, allowing for efficient engagement with a guide rail, and a retaining assembly that moves between positions to engage or disengage the brake members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional braking systems with governors, governor ropes, tension devices and safety actuation modules are used, then reliable braking can be achieved, but the system complexity increases significantly

Engineering Contradiction:
Improvebraking reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the governor, governor rope, and tension device from the traditional braking system. The safety actuation module is redesigned to directly actuate the brake shoe through a linkage mechanism, removing unnecessary intermediate components while maintaining braking reliability through the direct mechanical connection between the actuator and brake application point.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the safety actuation function and brake application function into a single integrated mechanism. The safety actuation module with its linkage system merges multiple functions (actuation, force transmission, brake application) into one compact assembly, reducing the overall number of separate components needed in the system.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple components like governors and tension devices are used, then braking function can be ensured, but the ease of manufacture decreases

Engineering Contradiction:
Improvebraking functionVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By removing the governor and tension device components, the patent reduces the number of parts that need to be manufactured, assembled, and tested. This extraction of unnecessary components directly improves ease of manufacture while the retained components (actuator, linkage, brake shoe) are designed to perform multiple functions efficiently.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If a simplified mechanism with fewer components is used, then ease of manufacture improves, but the reliability of braking may be compromised

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidbraking reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent maintains reliability by designing an integrated safety actuation module where the actuator, linkage, and brake shoe work together as a unified system. This merging of functions into fewer components reduces potential failure points from component interfaces while maintaining the essential braking function through robust mechanical design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The linkage mechanism is designed to automatically translate actuator motion into brake shoe application without requiring external control systems or additional components. The mechanical linkage self-regulates the force transmission and brake application, providing inherent reliability through passive mechanical design rather than active control.

Inventive Principle:
Principle #25Self-service

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

This solution simplifies the braking system by reducing components while ensuring reliable and stable braking of hoisted structures, effectively engaging and disengaging brake members with the guide rail to control the movement of hoisted structures.

Implementation Method 1

a biasing member biasing the first brake member toward the braking position, the electric actuator exerting a force on the retaining assembly in the powered state that overcomes a biasing force exerted by the biasing member on the first brake member

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a first brake member coupled to the housing and having a first brake surface for frictionally engaging a first surface of a guide rail

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3381855B1Safety brake actuation mechanism for a hoisted structure
Publication Date: 2021.01.27 OTIS ELEVATOR CO
  • EP3381855B1 patent drawingFigure 1
  • EP3381855B1 patent drawingFigure 2
  • EP3381855B1 patent drawingFigure 3

AI summary

A safety brake actuation mechanism for a hoisted structure includes a housing operatively coupled to the hoisted structure. Also included is a first brake member coupled to the housing, the first brake member moveable between a braking position and a non-braking position. Further included is a retaining assembly moveable between a first position and a second position and engageable with the first brake member, the retaining assembly retaining the first brake member in the non-braking position in the first position and permitting the first brake member to move to the braking position in the second position. Yet further included is an electric actuator operatively coupled to the retaining assembly and biasing the retaining assembly to the first position in a powered state of the electric actuator, the retaining assembly movable to the second position in a non-powered state of the electric actuator.