Stepladder Automatic Leg Deployment Mechanism

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Solution Overview

Problem

Existing stepladders require human intervention to deploy and adjust stabilizing legs for improved stability, which can be inconsistent and unsafe, especially when working at heights between 2.5 and 4 meters, and do not meet modern safety regulations for operator safety.

Innovation Solution

A stepladder with automatically separating and adjusting support legs, utilizing spreader arms and tie rods that deform to move legs apart and compensate for uneven surfaces, eliminating the need for manual deployment and ensuring increased stability without human intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If manual deployment of stabilizing legs is used, then stability can be improved when deployed, but reliability deteriorates due to inconsistent human intervention and failure to deploy

Engineering Contradiction:
ImprovestabilityVSAvoidreliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The stabilizing legs are equipped with automatic deployment mechanisms that activate when the stepladder is set up, eliminating the need for manual intervention. The legs automatically extend and lock into position, ensuring consistent deployment every time the stepladder is assembled, thus maintaining reliability while achieving stability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The stabilizing legs are pre-positioned in a retracted state during manufacturing, and the deployment mechanism is pre-configured to automatically activate when the stepladder is assembled. This preliminary preparation ensures that the legs are ready to deploy immediately when needed, without requiring human judgment or action.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If stabilizing legs are added to improve stability, then stability improves, but device complexity increases due to additional components and manual deployment requirements

Engineering Contradiction:
ImprovestabilityVSAvoiddevice complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The deployment mechanism for the stabilizing legs is integrated into the existing stepladder assembly structure. The same locking and connecting mechanisms used for the main ladder structure are also utilized for the stabilizing legs, combining multiple functions into unified components rather than adding separate independent systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stabilizing legs serve multiple functions: they provide lateral stability, prevent the stepladder from tipping sideways, and also act as additional support points for the user. This multi-functionality reduces the need for separate stabilization components, simplifying the overall device structure.

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

3Device complexity

If support polygon is reduced to traditional stepladder footprint, then device complexity is minimized, but stability deteriorates making falls more likely

Engineering Contradiction:
Improvedevice complexityVSAvoidstability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The support base is segmented into multiple independent elements: the main stepladder footprint and the extendable stabilizing legs. This segmentation allows the support polygon to dynamically expand from a compact configuration to an extended stable configuration, providing both compact storage and enhanced stability when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stabilizing legs extend the support polygon in the lateral dimension, perpendicular to the main climbing plane. This adds a new dimensional aspect to the support base, creating a wider, more stable footprint that prevents sideways tipping while maintaining the original compact structure when legs are retracted.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2078819B1Stepladder with folding platform and separable support legs
Publication Date: 2010.09.29 AUDINNOV
  • EP2078819B1 patent drawingFigure 1~2
  • EP2078819B1 patent drawingFigure 3
  • EP2078819B1 patent drawingFigure 4~6

AI summary

The ladder has an automatic shifting unit for shifting support legs (6). The unit has a spacer arm (22) placed below a foldable platform (4). The arm has an end articulated on a pivot (23), and another end articulated on a collar (8) that is assembled on the corresponding leg. A lateral tie rod (10) has an end connected to the collar by a hinge (9), and another end connected to posts (2) by a hinge (12). The arm and the rod form two sides of a triangle. Third side of the triangle is formed between the pivot and the hinge (12) and modifies the position of the collar on the leg.