Roller-Based Elevator Braking Mechanism

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Solution Overview

Problem

Existing elevator braking systems face issues with variability in braking efficiency due to factors like lubricants, moisture, and debris affecting the coefficient of friction on guiderails, leading to inconsistent stopping performance.

Innovation Solution

The braking device employs rollers that are biased to engage the guiderail without sliding, utilizing internal friction between the roller periphery and a braking surface to apply a consistent braking force, eliminating the need for components that contact the guiderail surface directly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If brake pads are forced against the guiderail surface, then a braking force is applied to decelerate the car, but braking efficiency varies due to lubricants, moisture, and debris affecting the coefficient of friction

Engineering Contradiction:

Improvebraking forceVSAvoidbraking efficiency consistency

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent introduces rollers as intermediary elements between the brake pads and the guiderail. The brake pads apply braking force to the rollers, which then roll along the guiderail surface without sliding. This intermediary mechanism eliminates direct sliding friction between brake pads and guiderail, making the braking system immune to variations in the coefficient of friction caused by lubricants, moisture, and debris on the guiderail surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional sliding friction-based braking mechanism with a rolling friction-based mechanism. Instead of brake pads sliding against the guiderail surface, the system uses rollers that rotate along the guiderail. This substitution of mechanical principle (from sliding friction to rolling friction) ensures consistent braking performance regardless of surface conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If brake pads contact the guiderail surface directly, then braking is achieved, but the braking force is affected by external factors like lubricants and moisture

Engineering Contradiction:

Improvebraking mechanism simplicityVSAvoidexternal factors affecting braking

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The rollers serve as protective intermediary elements that shield the braking system from harmful external factors. By transferring the braking action from direct pad-to-rail contact to pad-to-roller contact with rolling motion, the system isolates the braking mechanism from the influence of lubricants, moisture, and debris on the guiderail surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If rollers are used to engage the guiderail, then internal friction provides consistent braking, but the device complexity increases

Engineering Contradiction:

Improvebraking consistencyVSAvoidbraking device structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The rollers perform multiple functions simultaneously: they serve as the contact surface for brake pad application, act as rolling elements to eliminate sliding friction, and function as the component that rolls along the guiderail. This multi-functionality achieves reliable and consistent braking without requiring complex additional mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 provides a robust and consistent braking mechanism that is less affected by external factors, ensuring reliable deceleration of elevator cars by leveraging internal friction within the braking device.

Implementation Method 1

A biasing member pushes the roller against a surface of the guiderail

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

Friction between the periphery of the associated roller and the braking surface provides a stopping force

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS9821983B2Elevator braking device

Publication Date: 2017.11.21 OTIS ELEVATOR CO

AI summary

An exemplary elevator braking device comprises a brake housing. A plurality of rollers are supported by the brake housing. The rollers are arranged to be positioned on opposite sides of a guiderail. The rollers are selectively moveable between a first position in which the rollers are spaced apart a first distance and a second position in which the rollers are spaced apart a second, smaller distance so that the rollers engage and roll along opposite sides of the guiderail. At least one biasing member is supported by the brake housing. The biasing member is associated with at least one of the rollers and biases the associated roller toward the other roller in the second position. A plurality of braking surfaces are supported by the brake housing. At least one braking surface is associated with each of the rollers. Each braking surface engages a periphery of the associated roller that faces the side of the guiderail. Friction between the periphery of the associated roller and the braking surface provides a stopping force.