Stepladder Bracket Design for Stability and Play Reduction

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Solution Overview

Problem

Existing climbing devices, such as folding steps or ladders, suffer from instability and lack of a firm holding mechanism due to non-parallel bars and absence of stabilizing elements in the upper connection area, leading to play in the guide and inadequate support for users.

Innovation Solution

A second bracket is introduced to connect the upper ends of the bars, providing additional stability through a cross brace and an enhanced holding option, with a work tray optionally integrated into this bracket, and the first bracket is designed with U-shaped legs that can be slidably mounted with minimal play within the bars.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the first bracket is guided on the outside of the two bars, then the bracket can be attached to the folding step, but the guide has play due to non-parallel bars, resulting in insufficient firm hold for the user

Engineering Contradiction:
Improvefirm hold for userVSAvoidstability of bracket guide
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The legs of the first bracket are received within the bars of the folding step, forming a nested structure. This nesting eliminates the external guide configuration and provides a firm hold for the user while maintaining stability.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If the pairs of bars are connected only by steps or struts without stabilizing elements, then the structure remains simple, but the folding step lacks stability particularly in the upper area

Engineering Contradiction:
Improvesimplicity of structureVSAvoidstability of folding step
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The second bracket merges the two bars of at least one pair of bars at their upper ends, creating a combined structural element. This merging provides additional stability to the folding step, particularly in the upper area, while maintaining relatively simple construction.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If a second bracket is added to connect the upper ends of the bars, then stability and holding option are improved, but the device complexity increases

Engineering Contradiction:
Improvestability of climbing deviceVSAvoidnumber of brackets
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The second bracket serves multiple functions: it connects the two bars to provide structural stability, acts as a stabilizing element to dissipate torques and forces, and provides an additional holding point for the user. This multi-functionality justifies the addition despite increased complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP1956182B1Ladder with a height-adjustable holder
Publication Date: 2013.02.20 HAILO WERK RUDOLF LOH
  • EP1956182B1 patent drawingFigure 1
  • EP1956182B1 patent drawingFigure 2
  • EP1956182B1 patent drawingFigure 3

AI summary

A stepladder (1) has a main frame (2) that terminates ins a cross-member (5). The side-frame has height-adjustable sliding retractable metal rods (7) linked by a plastic cross-member (8).