Spout Thread Geometry for Easier Demolding in Packaging Boxes
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Solution Overview
Problem
The difficulty in demolding the mouth portion casting of beverage packaging boxes due to the deep internal thread, which requires significant thrust and can cause deformation during manufacturing, is a challenge in existing designs.
Innovation Solution
The spout packaging structure incorporates a first internal thread with inclined surfaces on the protruding tooth structures, featuring angles between 110° and 145°, to reduce demolding resistance and wear, and a thread depth of at least 55% of the wall thickness, ensuring a stable fit with the cutting element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal thread of the mouth portion is made deep to ensure stable fit with the cutting element, then the fitting stability is improved, but the demolding resistance increases and demolding becomes difficult
Solution Approach 1:
The patent changes the geometric parameters of the thread structure by setting specific angle ranges (α≥110°, β≥90°) for the inclined surfaces, and controlling the thread depth relative to wall thickness (≥55%), thereby optimizing both fitting stability and demolding ease simultaneously
Solution Approach 2:
The patent introduces curved transition surfaces at the root of the thread (with radius R1≥0.15mm) and optimizes the inclination angles of the thread flanks, creating a more rounded and smooth thread geometry that reduces stress concentration and facilitates demolding while maintaining fitting stability
2Reliability
If the internal thread depth is increased to prevent cutting element slippage, then the anti-slip performance is improved, but the wear and undercut of the thread increase
Solution Approach 1:
The patent optimizes the thread geometry by controlling the inclination angles (α and β) and the depth-to-thickness ratio (≥55%), which distributes the load more evenly across the thread engagement length, reducing localized wear and undercut while preventing cutting element slippage
Solution Approach 2:
The patent introduces fillet radii (R1≥0.15mm) at the thread root and optimizes the curvature of the thread flanks, which reduces stress concentration and prevents thread degradation from wear and undercut, thereby maintaining anti-slip performance without compromising thread integrity
Data Source
AI summary
A spout packaging structure includes a spout structure, a cutting element, and a cap. The spout structure includes a fixing part and a mouth part connected to the fixing part. The mouth part has a cylindrical structure and first internal threads. Each protruding tooth structure of the first internal threads is provided with first and second inclined surfaces located on two sides of the protruding tooth structure with a recessed structure between two adjacent protruding ones. The first inclined surface faces the fixing part. Within a same cross section through the mouth part's axis, the bottom of the recessed structure has a tangent parallel to the mouth part's axis, angle α between the first inclined surface and the tangent is 110°-145°, and angle β between the second inclined surface and the tangent is at least 90°. The cutting element is sleeved in the mouth part with first external threads.