Retractable Lifeline Brake Assembly With Sequential Brake Tabs

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Solution Overview

Problem

Friction-based braking mechanisms in retractable lifelines are prone to erosion, compromising control over fall arrest forces and potentially leading to insufficient limitation of forces applied to the lifeline and the user.

Innovation Solution

A brake assembly with a brake plate and extension member that successively engage radially extending brake tabs, allowing for controlled forces during a braking event, where the extension member is movable relative to the brake plate and configured to engage the tabs upon rotational forces, providing a mechanical advantage and energy absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If friction-based braking mechanisms are used, then braking force is provided, but the mechanism is prone to erosion over time compromising control

Engineering Contradiction:

Improvebraking forceVSAvoidcontrol reliability

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent replaces friction-based braking with a mechanical engagement system consisting of brake tabs and an extension member. The brake tabs radially extend from the brake plate and engage with the extension member through sequential mechanical contact, eliminating reliance on friction surfaces that erode over time. This mechanical engagement provides reliable force transmission without the wear problems inherent in friction-based systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Force

If friction-based braking mechanisms are used, then braking function is achieved, but fall arrest forces are not sufficiently limited

Engineering Contradiction:

Improvebraking functionVSAvoidexcessive fall arrest forces

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The brake plate is segmented into multiple radially extending brake tabs spaced circumferentially around the plate. During braking, these tabs engage the extension member in sequence, distributing the braking action across multiple contact points and time intervals. This segmentation allows for progressive force application and dissipation, preventing sudden excessive force spikes that could harm the user during fall arrest.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sequential engagement of multiple brake tabs creates a periodic braking action as each tab successively contacts the extension member during rotation. This periodic engagement pattern modulates the braking force over time, allowing energy dissipation through repeated cycles of engagement and disengagement rather than continuous friction, thereby limiting peak forces.

Inventive Principle:

Principle #19Periodic action

3Ease of operation

If friction-based braking mechanisms are used, then braking control is provided, but the mechanism erodes potentially compromising safety

Engineering Contradiction:

Improvebraking controlVSAvoidsafety reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent substitutes friction-based braking control with a positive mechanical engagement system. The brake tabs and extension member form interlocking elements that provide deterministic control through geometric constraints rather than friction coefficients. This mechanical linkage maintains consistent braking characteristics without degradation from wear, ensuring long-term safety reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively manages and controls forces during a braking event, ensuring adequate limitation of fall arrest forces and maintaining the integrity of the braking mechanism over time, thereby enhancing user safety.

Implementation Method 1

The extension member is movable relative to the brake plate such that the extension member is configured to successively engage the brake tabs... providing a mechanical advantage and energy absorption

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentUS11117002B2Brake assembly for use with retractable lifeline assembly

Publication Date: 2021.09.14 PURE SAFETY GROUP INC

AI summary

A brake assembly comprises a brake plate including a plurality of radially-extending brake tabs, and an extension member extending at least partially through the brake plate. The extension member is movable relative to the brake plate such that the extension member is configured to successively engage the brake tabs. The brake assembly enables one or more forces to be managed or controlled throughout a braking event, such as a fall arrest event.