Shell-Shaped Locking Convex Part for Storage Case Hinge
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Solution Overview
Problem
Conventional storage case hinge structures experience dimensional instability and noise due to sink marks in the locking projections, leading to ineffective engagement and reduced durability from abrasion, as the locking projections and engagement members are prone to wear from repeated use.
Innovation Solution
A shell-shaped locking convex part recessed from the rear side of the front cover, with a slope surface for gradual stress increase and a locking surface for self-weight retention, engages with an engagement part to maintain the front cover in an open state, preventing sink marks and wear, and reducing noise during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the locking projection is formed with increased thickness to ensure engagement, then the engagement reliability is improved, but sink marks occur during injection molding causing dimensional instability
Solution Approach 1:
The locking projection is divided into two separate components: the projection on the front cover and the engagement member on the upper cover. This segmentation allows each part to be optimized independently, eliminating sink marks while ensuring reliable engagement.
Solution Approach 2:
The engagement member is extracted from the front cover and placed on the upper cover instead. This extraction removes the problematic thick projection from the injection molding process, preventing sink marks while maintaining the locking function.
2Ease of manufacture
If the locking projection and engagement member have small widths to reduce material, then the manufacturing cost is reduced, but internal stress is released at once causing loud noise
Solution Approach 1:
The engagement member is designed with a curved engagement surface that provides gradual stress release, while the locking projection maintains appropriate width for structural integrity. This local quality optimization reduces noise without excessive material use.
3Ease of manufacture
If the locking projection and engagement member have small widths to reduce material, then the manufacturing cost is reduced, but the engagement members wear away quickly reducing durability
Solution Approach 1:
The engagement member features a curved engagement surface that distributes contact stress over a larger area, reducing wear on both the projection and engagement member while maintaining compact dimensions.
Solution Approach 2:
The engagement surface of the engagement member is designed as a curved surface rather than a flat surface. This curvature allows for gradual engagement and distributes wear more evenly, significantly improving durability while keeping the component compact.
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
The shell-shaped locking convex part enhances dimensional stability and durability by preventing sink marks and wear, ensuring reliable engagement and reduced noise, allowing the front cover to be securely held in the open state without user intervention.
Implementation Method 1
the locking convex part engages with the engagement part so that the front cover is locked in the second opened state
Implementation Method 2
a slope surface for gradual stress increase
Implementation Method 3
a locking surface for self-weight retention
Data Source
AI summary
A storage case includes a front cover. An upper side of the front cover is rotatably connected to a top plate via a hinge structure. An outwardly protruding locking convex part is formed on the upper side of the front cover. In a first opened state where the front cover is turned upward about the upper side of the front cover as an axis, the locking convex part comes into contact with an engagement part on the top plate. When the front cover is turned upward from the first opened state and becomes in a second opened state in which the engagement part passes over the locking convex part, the locking convex part engages with the engagement part so that the front cover is locked in the second opened state. The locking convex part is recessed from a rear side of the front cover to be in a shell-shaped form.