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
Engineering 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
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.
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
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.
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
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.
Data Source
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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.