Ladder Bracket Play-Free Connection Eliminates Rattling

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Solution Overview

Problem

Users of existing stepladders may perceive the ladders as not solid due to rattling noises caused by the movement of the bracket relative to the tube or bolt of the support part, leading to confusion between latching and rattling sounds, which affects the user's feeling of safety and solidity.

Innovation Solution

The bracket is designed to surround the pipe or bolt without play under pretension, eliminating rattling noises by ensuring a play-free connection, and the platform locks into place with a distinct snapping sound when unfolded, distinguishing it from rattling noises.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the bracket is allowed to move relative to the tube or bolt of the support part, then the connection mechanism provides flexibility and latching function, but rattling noises occur when the platform is alternately loaded and unloaded

Engineering Contradiction:
Improvelatching functionVSAvoidrattling noises
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by introducing a pretension force that modifies the physical state of the bracket-tube connection. The bracket is designed with a geometry that creates inherent pretension, causing the bracket to press against the tube without play. This changes the connection from a loose, noisy state to a tight, silent state while preserving the latching functionality through the same geometric design.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the bracket is designed with play-free connection under pretension, then rattling noises are eliminated, but the complexity of the bracket design increases

Engineering Contradiction:
Improverattling noisesVSAvoidbracket design
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The bracket design uses parameter changes by incorporating a specific geometric configuration that generates pretension forces. The non-symmetric shape of the bracket, with its specific arm lengths and attachment point positions, creates a mechanical lever effect that produces the necessary pretension to eliminate play and rattling noises without requiring additional components or complex mechanisms.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the bracket is made with a wire bent into shape or as a plastic injection molded part, then manufacturing ease is improved, but ensuring play-free connection under pretension requires precise manufacturing tolerances

Engineering Contradiction:
Improvebracket productionVSAvoidconnection tolerance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent addresses the manufacturing precision challenge by designing the bracket with built-in compensation mechanisms. The geometric design includes features such as the specific arrangement of attachment points and the non-symmetric shape that create pretension through mechanical leverage rather than relying solely on tight tolerances. This allows standard manufacturing processes to produce the bracket while still achieving the play-free connection required to eliminate rattling noises.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2360345B1Ladder, in particular step ladder or folding step ladder, with a platform, an ascending part, a support part and a frame
Publication Date: 2018.01.10 HAILO WERK RUDOLF LOH
  • EP2360345B1 patent drawingFigure 1
  • EP2360345B1 patent drawingFigure 2
  • EP2360345B1 patent drawingFigure 3

AI summary

The ladder has a climbing part (10) with two bars that are connected with each other by stages and/or attachment parts. A support part (20) includes two bars that are connected with each other and with a frame (40). The climbing part and the support part are pivotally connected with each other. A platform (30) is pivotally attached at the climbing part, and the frame is pivotally attached at the support part. The frame surrounds a pipe (23) or a bolt of the support part in a play-free manner. The frame is articulately connected with the platform.