Convertible Ladder Joint Heads for Half-Step Alignment

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing convertible ladder joints fail to ensure user safety by not adequately compensating for uneven surfaces and maintaining proper vertical positioning during double laddering, as they lack precise adjustment mechanisms and may not prevent disengagement during extension.

Innovation Solution

The introduction of joint heads with specific shapes and studs that allow for offset adjustments at half-step intervals, ensuring precise alignment and preventing plane spacing unless opposite rungs or studs are aligned, along with hooks that engage rungs for stability and limit deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional joint heads are used, then the ladder can be deployed in double position, but the offset adjustment is limited to full step intervals, reducing positioning precision on uneven surfaces

Engineering Contradiction:
Improveoffset adjustment precisionVSAvoidjoint head structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The joint head structure is segmented into multiple functional elements: external shapes for rung engagement, studs for half-step positioning, and lips for guidance. This segmentation allows each element to perform a specific function, achieving half-step adjustment precision without overwhelming complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Studs are introduced as intermediary elements between the rungs and the joint head body. These studs protrude from the inner face and can be housed in the shape provided on the plan, enabling half-step offset adjustments by providing intermediate positioning points between full rung intervals

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the ladder allows free sliding between planes, then ease of operation is improved, but safety is compromised due to potential disengagement

Engineering Contradiction:
Improveplane sliding easeVSAvoidengagement stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Hooks with folded locks are provided as preliminary protective measures against disengagement. The folded lock prevents disengagement by mechanically blocking the separation path, while the hook engages the rung to maintain connection. This preliminary anti-action ensures safety while allowing controlled sliding motion

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The joint head structure incorporates dynamic elements that allow controlled movement: lips guide the sliding motion between planes, while hooks provide conditional engagement that transitions from locked to unlocked states. This dynamic design enables ease of operation during intended use while maintaining reliability through controlled engagement mechanisms

Inventive Principle:
Principle #15Dynamics

3Reliability

If hooks are added to prevent disengagement, then safety is improved, but the device complexity increases

Engineering Contradiction:
Improveengagement stabilityVSAvoidjoint head structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hook and folded lock are merged into a single integrated component rather than separate parts. The hook engages the rung while the folded lock provides the prevention mechanism, combining multiple safety functions into one element. This merging reduces overall complexity while maintaining the reliability benefits of disengagement prevention

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP1832709B1Joint heads for combination ladders
Publication Date: 2013.11.27 MACC
  • EP1832709B1 patent drawingFigure 1
  • EP1832709B1 patent drawingFigure 2
  • EP1832709B1 patent drawingFigure 3

AI summary

The head has outer shapes (15, 16) carried by flanges (7, 8) permitting engagement of one of ladder rungs (4) or one of posts (5, 5`) between cutting edges (13, 13`) of the head for spacing of planes (1, 2). The post is situated in a middle of the rung on an inner surface of columns (17, 18) of the plane (1). Return supports on the columns of the plane (2) in a manner to rigidify the transformable ladder into painter`s ladder.