Telescopic Ladder Stabiliser Bar Mechanical Interlock

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Solution Overview

Problem

Users often fail to deploy retractable stabiliser bars on collapsible ladders due to laziness or forgetfulness, which compromises the ladder's stability during use.

Innovation Solution

A collapsible ladder design where an inextensible member connected to the uppermost section is secured to the foot via a catch mechanism, allowing extension only when the stabiliser bars are deployed, and a resiliently biased detent prevents retraction until the ladder is fully collapsed, ensuring the stabiliser bars are always deployed for use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the stabiliser bars are made retractable for storage convenience, then the ease of operation is improved, but the reliability of stabiliser deployment is worsened because users may forget or neglect to deploy them

Engineering Contradiction:

Improvestorage convenienceVSAvoidstabiliser deployment reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system automatically ensures proper stabilizer deployment through mechanical interlocking. The catch mechanism on the inextensible member automatically engages with the stabilizer bar in its deployed position, making the safety function self-enforcing without relying on user memory or attention. The system serves itself by design rather than requiring user service.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The stabilizer bar must be deployed before the ladder can be extended for use. The catch mechanism is designed so that the inextensible member can only be released after the stabilizer bar is in its deployed position, performing the safety action preliminarily before the main function of ladder extension.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the ladder allows free extension regardless of stabiliser position, then the ease of operation is improved, but the stability of the ladder is worsened due to potential sideways toppling

Engineering Contradiction:

Improveladder extension freedomVSAvoidladder lateral stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The catch mechanism prevents the harmful action of extending the ladder without stabilizers by requiring the stabilizer bar to be in the deployed position first. The mechanical interlock creates a preliminary barrier that blocks the unsafe configuration before it can occur.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The catch mechanism acts as an intermediary between the stabilizer bar position and the ladder extension capability. It mediates the interaction by allowing extension only when the stabilizer is properly deployed, translating the stabilizer's position into permission for ladder extension.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a catch mechanism is added to control stabiliser deployment, then the reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvestabiliser deployment reliabilityVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The catch mechanism is merged with the existing inextensible member that is already part of the telescopic ladder structure. The inextensible member serves dual purposes: maintaining ladder section spacing and controlling stabilizer deployment through its catch mechanism, combining multiple functions into a single component.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The inextensible member is given multiple functions: it maintains proper spacing between telescopic ladder sections and simultaneously controls stabilizer bar deployment through its catch mechanism. This multi-functionality reduces the need for separate dedicated components for each function.

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

Ensures the ladder can only be extended with correctly deployed stabiliser bars, enhancing safety by maintaining lateral stability and preventing accidental retraction during use.

Implementation Method 1

a resiliently biased detent is provided to prevent movement of the stabiliser bar away from the deployed position

Methodology Applied

Scientific EffectResilient bias: Elasticity

Data Source

PatentUS10808460B2Telescopic ladder with retractable stabiliser bars

Publication Date: 2020.10.20 WERNER UK SALES & DISTRIBUTION LTD

AI summary

A collapsible ladder (10) is disclosed having rungs secured to telescopically collapsible stile sections and at least one stabiliser bar secured to the foot of the ladder, the (or each) stabiliser bar (12a, 12b) being displaceable between a storage position in which the bar lies, at least predominantly, between the two stiles and a deployed position in which the bar widens the footprint of the ladder to improve the lateral stability of the ladder. A rod (20) is connected to extend downwardly from the uppermost stile section of the ladder and a catch mechanism (30) is provided at the foot of the ladder to engage the lower end of the rod to prevent the ladder from being extended. The catch mechanism (30) is operable by the (or a) stabiliser bar to release the rod and permit the ladder to be extended only when the stabiliser bar is in the deployed position.