Multipurpose Ladder Thinner Rails Bracket Reinforcement
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Solution Overview
Problem
Existing multipurpose ladders struggle to achieve a balance between being lightweight and maintaining structural integrity, often failing to support loads safely due to excessive weight reduction, which is a concern for ANSI duty ratings.
Innovation Solution
The design incorporates thinner rails with strategically positioned brackets to enhance bending strength, optimized hinge plates and rungs, and a weight-saving approach that maintains structural integrity while meeting ANSI standards, including a weight-to-length ratio of less than 2.41 lbs/ft for IAA-rated ladders and 1.90 lbs/ft for IA-rated ladders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the ladder is made with thinner rails to reduce weight, then the weight is reduced, but the bending strength and structural integrity deteriorate
Solution Approach 1:
The patent applies local quality by positioning brackets at specific locations along the rails where bending moments are highest. These brackets provide localized reinforcement exactly where needed, allowing the rails to be thinner overall while maintaining strength at critical points. The brackets are strategically placed at higher bending force locations to buttress the rails precisely where the structural demands are greatest.
Solution Approach 2:
The patent employs composite construction by combining the rail material with bracket reinforcements. The brackets act as composite elements that work together with the thinner rails to achieve the required bending strength. This composite approach allows the overall structure to be lighter than a solid thick-rail design while meeting ANSI duty rating requirements.
2Weight of moving object
If the rails are made thinner to achieve lower weight-to-length ratio, then the weight-to-length ratio is reduced, but the ability to support loads safely deteriorates
Solution Approach 1:
The brackets are positioned at specific locations where bending forces are highest, providing localized reinforcement that ensures safe load support. This targeted approach allows the rails to be thinner overall while maintaining reliability at critical stress points, achieving both lower weight-to-length ratio and safe load support capability.
Solution Approach 2:
The brackets are pre-positioned at locations determined to experience higher bending forces during normal ladder use. This preliminary placement of reinforcement elements ensures that the structure is prepared in advance to handle expected loads safely, allowing thinner rails while maintaining reliability.
3Weight of moving object
If weight reduction measures are taken to achieve lighter ladder, then portability is improved, but structural integrity and ANSI compliance deteriorate
Solution Approach 1:
By applying brackets only at specific locations where reinforcement is needed rather than uniformly throughout the rails, the patent achieves weight reduction while maintaining structural integrity. The localized reinforcement strategy ensures ANSI compliance at critical points without the penalty of uniform thickening that would compromise portability.
Solution Approach 2:
The composite construction of thinner rails with bracket reinforcements enables the ladder to be lighter for improved portability while the bracket-rail composite structure maintains the structural integrity required for ANSI compliance.
Data Source
AI summary
In some embodiments, a multipurpose ladder has a first inner section. The ladder has a first articulated hinge and a second articulated hinge. The ladder has a second inner section. The ladder has a first outer section. The ladder has a first locking bar. The ladder has a second outer section. The multipurpose ladder may have a plurality of brackets disposed about outer rails of the outer sections. The brackets provide support to each of the outer rails and strengthens them against bending forces so the rails can be thinner and of lighter weight. The ladder may have an ANSI duty rating of 1 A or an ANSI duty rating of 1 AA.