Lid Positioning Rib Structure to Prevent Freezing Fixation
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Solution Overview
Problem
Existing lid opening/closing devices are prone to freezing due to large contact areas between engagement recess and projection portions, causing the base member and lid to become fixed in winter.
Innovation Solution
A lid opening/closing device with a positioning portion that includes an engagement recess and projection, where one of these features has a rib extending in the up-down direction, reducing contact area and preventing freezing fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the engagement recess portion and engagement projection portion are configured to oppose each other with large contact area, then the positioning accuracy is improved, but the base member and lid are likely to be fixed together due to freezing
Solution Approach 1:
The engagement surfaces are segmented into multiple small contact points through the rib structure, rather than having a large continuous contact area. This segmentation reduces the total area where water can accumulate and freeze, while still maintaining adequate positioning through the distributed contact points.
Solution Approach 2:
The rib structure creates local quality differences in the engagement interface, with specific localized contact areas rather than uniform contact across the entire surface. This allows positioning functionality to be concentrated in specific regions while minimizing the overall contact area that could lead to freezing.
2Stability of the object's composition
If the contact area between engagement portions is large, then the positioning stability is improved, but the force required to open the lid increases due to freezing
Solution Approach 1:
The engagement interface is divided into multiple discrete contact points via ribs, providing sufficient positioning stability through distributed contacts while minimizing the continuous surface area that would otherwise freeze and increase opening force.
3Manufacturing precision
If the engagement surfaces are configured with large overlapping area, then the positioning precision is improved, but water accumulation and freezing risk increase
Solution Approach 1:
The rib structure segments the engagement surfaces into discrete contact regions, reducing the continuous overlapping area where water can accumulate. This maintains positioning precision through accurate rib-to-surface engagement while minimizing the volume available for water accumulation and subsequent freezing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents the base member and lid from freezing together by minimizing contact area and limiting frozen water accumulation, allowing easy separation even in cold conditions.
Implementation Method 1
a region where the water accumulating between the engagement recess portion and the engagement projection portion in the engagement state is frozen spans over a wide range, so that the base member and the lid are likely to be fixed to each other due to freezing
Data Source
AI summary
A lid opening/closing device includes: a base member provided with an opening; a lid configured to open/close the opening; and a positioning portion configured to position at least a vertical position of the lid relative to the base member at a closed position of the lid. The positioning portion includes an engagement recess portion provided to the base member in a recess shape, and an engagement projection portion provided to the lid in a projection shape and configured to be engaged with the engagement recess portion at least in an up-down direction at the closed position of the lid. The engagement recess portion includes a rib extending in the up-down direction at the closed position of the lid. The rib is engaged at a distal end thereof with the engagement projection portion at the closed position of the lid.